diff --git a/Generators/BeamHaloGenerator/src/BeamHaloGeneratorSettings.cxx b/Generators/BeamHaloGenerator/src/BeamHaloGeneratorSettings.cxx
index 913723d6bede23a66f04e5014f089b9b916f6d98..f3d9825e12fe8be884f97476eefb19941f971795 100644
--- a/Generators/BeamHaloGenerator/src/BeamHaloGeneratorSettings.cxx
+++ b/Generators/BeamHaloGenerator/src/BeamHaloGeneratorSettings.cxx
@@ -156,20 +156,20 @@ bool BeamHaloGeneratorSettings::checkParticle(BeamHaloParticle *beamHaloParticle
 
   // First implement the cuts which are not related to the particle
   // trajectory.
-  if(!checkSetting(W_LIMIT, fabs(beamHaloParticle->weight()))) return false;
-  if(!checkSetting(PX_LIMIT, fabs(beamHaloParticle->fourVector().px()))) return false;
-  if(!checkSetting(PY_LIMIT, fabs(beamHaloParticle->fourVector().py()))) return false;
-  if(!checkSetting(PZ_LIMIT, fabs(beamHaloParticle->fourVector().pz()))) return false;
-  if(!checkSetting(E_LIMIT, fabs(beamHaloParticle->fourVector().e()))) return false;
+  if(!checkSetting(W_LIMIT, std::abs(beamHaloParticle->weight()))) return false;
+  if(!checkSetting(PX_LIMIT, std::abs(beamHaloParticle->fourVector().px()))) return false;
+  if(!checkSetting(PY_LIMIT, std::abs(beamHaloParticle->fourVector().py()))) return false;
+  if(!checkSetting(PZ_LIMIT, std::abs(beamHaloParticle->fourVector().pz()))) return false;
+  if(!checkSetting(E_LIMIT, std::abs(beamHaloParticle->fourVector().e()))) return false;
   if(!checkSetting(PT_LIMIT, beamHaloParticle->fourVector().perp())) return false;
-  if(!checkSetting(ETA_LIMIT, fabs(beamHaloParticle->fourVector().pseudoRapidity()))) return false;
-  if(!checkSetting(PHI_LIMIT, fabs(beamHaloParticle->fourVector().phi()))) return false;
+  if(!checkSetting(ETA_LIMIT, std::abs(beamHaloParticle->fourVector().pseudoRapidity()))) return false;
+  if(!checkSetting(PHI_LIMIT, std::abs(beamHaloParticle->fourVector().phi()))) return false;
 
 
   // Require the selection at the scoring plane.
   if(m_shapeRequirement == NONE) {
-    if(!checkSetting(X_LIMIT, fabs(beamHaloParticle->positionAtScoringPlane().x()))) return false;
-    if(!checkSetting(Y_LIMIT, fabs(beamHaloParticle->positionAtScoringPlane().y()))) return false;
+    if(!checkSetting(X_LIMIT, std::abs(beamHaloParticle->positionAtScoringPlane().x()))) return false;
+    if(!checkSetting(Y_LIMIT, std::abs(beamHaloParticle->positionAtScoringPlane().y()))) return false;
     if(!checkSetting(R_LIMIT, beamHaloParticle->positionAtScoringPlane().perp())) return false;
   }
   else if(m_shapeRequirement == CYLINDER) {
diff --git a/Generators/BeamHaloGenerator/src/BeamHaloParticle.cxx b/Generators/BeamHaloGenerator/src/BeamHaloParticle.cxx
index 604c4c6ecb2f5b4e9cb9c28500a93eeb90766575..d2fd480d942bde87da3e4f5ac43f066ab92c8b19 100644
--- a/Generators/BeamHaloGenerator/src/BeamHaloParticle.cxx
+++ b/Generators/BeamHaloGenerator/src/BeamHaloParticle.cxx
@@ -155,7 +155,7 @@ int BeamHaloParticle::fill(const HepPDT::ParticleDataTable *particleDataTable,
   m_fourVector.setY(flukaParticle->directionalCosines().y() * mod_p);
 
   // If the z component of the directional cosine has not been set recalculate it.
-  if(fabs(flukaParticle->directionalCosines().z()) < 0.0001) {
+  if(std::abs(flukaParticle->directionalCosines().z()) < 0.0001) {
     // Calculate pz from sqrt(p^2 - p_T^2)
     pz = std::sqrt(p_sq - m_fourVector.perp2());
     m_fourVector.setZ(pz);  // This is always +ve.  Corrected during conversion to HepParticle
diff --git a/Generators/CavernBkgGenerator/src/MuonBackgroundConverter.cxx b/Generators/CavernBkgGenerator/src/MuonBackgroundConverter.cxx
index 1c1070e4d81a8e96331a93e2a508667e1de597c1..fe68fc75494b530b84fcc79f9cc692e188b1c307 100644
--- a/Generators/CavernBkgGenerator/src/MuonBackgroundConverter.cxx
+++ b/Generators/CavernBkgGenerator/src/MuonBackgroundConverter.cxx
@@ -195,7 +195,7 @@ StatusCode MuonBackgroundConverter::callGenerator()
          int id = abs (m_evt.at(i).getPdgID() );
          
          bool select = ( (!m_firstHitOnly) || 
-                         (m_firstHitOnly && fabs(p_curr-p_prev)>tolerance) ) && ( id != 13 ); 
+                         (m_firstHitOnly && std::abs(p_curr-p_prev)>tolerance) ) && ( id != 13 ); 
          if ( select )
          {
              //std::cout  <<  evt  <<  std::endl;
diff --git a/Generators/CavernBkgGenerator/src/MuonBackgroundEventParser.cxx b/Generators/CavernBkgGenerator/src/MuonBackgroundEventParser.cxx
index c1403c9d3596b09e1334e3ea1a33b0bfd9f1a302..bdca3ae2fb940829280a67acac000f8dc8772cdb 100644
--- a/Generators/CavernBkgGenerator/src/MuonBackgroundEventParser.cxx
+++ b/Generators/CavernBkgGenerator/src/MuonBackgroundEventParser.cxx
@@ -102,7 +102,7 @@ std::istream& MuonBackgroundEventParser::read( std::istream& is )
     m_momentum.setPz( p * pz1 * CLHEP::GeV );
   
     CLHEP::Hep3Vector mom = m_momentum.vect();
-    m_momentum.setE( sqrt( mass*mass + mom.mag2() ) );
+    m_momentum.setE( std::sqrt( mass*mass + mom.mag2() ) );
   }
   
   return is;
diff --git a/Generators/CosmicGenerator/src/CosmicGenerator.cxx b/Generators/CosmicGenerator/src/CosmicGenerator.cxx
index a8cd573dbe8fe264ace04008fc23f13bacee1dc8..b4ba40d23038e143992c38b22481477d4608dbdc 100644
--- a/Generators/CosmicGenerator/src/CosmicGenerator.cxx
+++ b/Generators/CosmicGenerator/src/CosmicGenerator.cxx
@@ -380,7 +380,7 @@ StatusCode CosmicGenerator::callGenerator() {
           double beta=direction.angle(center_dir);
           double alpha=asin(m_radius/center_dir.r());
 
-          if(fabs(beta)<alpha) {
+          if(std::abs(beta)<alpha) {
 
             if(m_exzCut) {
               // Old optimization code - is it still useful?
@@ -782,7 +782,7 @@ double CosmicGenerator::pathLengthInRock(double xgen, double ygen, double zgen,
 
   // does trajectory intersect p14 cylinder?
   double z_mid14 = (x0-p14_x)*sinphi-(z0-p14_z)*cosphi;
-  double min_dist14 = fabs(z_mid14);  //minimum distance of line from center
+  double min_dist14 = std::abs(z_mid14);  //minimum distance of line from center
   double shaft_distance14 = 0.;
   if (min_dist14<p14_radius) {
 
@@ -806,7 +806,7 @@ double CosmicGenerator::pathLengthInRock(double xgen, double ygen, double zgen,
 
   // does trajectory intersect p16 cylinder?
   double z_mid16 = (x0-p16_x)*sinphi-(z0-p16_z)*cosphi;
-  double min_dist16 = fabs(z_mid16);
+  double min_dist16 = std::abs(z_mid16);
   double shaft_distance16 = 0.;
   if (min_dist16<p16_radius) {
 
@@ -850,7 +850,7 @@ bool CosmicGenerator::pointsAtPixels(double xgen, double ygen, double zgen, doub
 
   ATH_MSG_VERBOSE("x_pos = " << x_pos << ", z_pos = " << z_pos);
 
-  if((fabs(x_pos)<m_pixelplanemaxx)&&(fabs(z_pos)<m_pixelplanemaxz)){
+  if((std::abs(x_pos)<m_pixelplanemaxx)&&(std::abs(z_pos)<m_pixelplanemaxz)){
     does=true;
   }
 
diff --git a/Generators/EvgenProdTools/src/SimTimeEstimate.cxx b/Generators/EvgenProdTools/src/SimTimeEstimate.cxx
index 1a3d6f223b6e57bb23369f5aaca45797d5f0e085..f3392250e46448fe35feb9a6f47976275f7757da 100644
--- a/Generators/EvgenProdTools/src/SimTimeEstimate.cxx
+++ b/Generators/EvgenProdTools/src/SimTimeEstimate.cxx
@@ -37,10 +37,10 @@ StatusCode SimTimeEstimate::execute()
             // Grab the momentum
             const HepMC::FourVector pmom = part->momentum();
             // Only count particles with finite eta
-            if (pmom.perp()==0 || fabs(pmom.eta())>m_etaMax) continue;
+            if (pmom.perp()==0 || std::abs(pmom.eta())>m_etaMax) continue;
             m_particleEtas.push_back(pmom.eta());
             // add  ID of particle to list 
-            m_particleIDs.push_back(abs(part->pdg_id()));
+            m_particleIDs.push_back(std::abs(part->pdg_id()));
             // add energy per particle to get the distribution:
             m_particleEnergies.push_back(pmom.e());
 
diff --git a/Generators/EvgenProdTools/src/TestHepMC.cxx b/Generators/EvgenProdTools/src/TestHepMC.cxx
index d1498cec589053c11e7bfc56d8597245d25462cb..c8dd06ff725ec59192741a43a6ded449beaa4b4b 100644
--- a/Generators/EvgenProdTools/src/TestHepMC.cxx
+++ b/Generators/EvgenProdTools/src/TestHepMC.cxx
@@ -300,7 +300,7 @@ StatusCode TestHepMC::execute() {
       const double sumP = beams.first->momentum().pz() + beams.second->momentum().pz();
       cmenergy = std::sqrt(sumE*sumE - sumP*sumP);
 
-      if (m_cm_energy > 0 && fabs(cmenergy - m_cm_energy) > m_cme_diff) {
+      if (m_cm_energy > 0 && std::abs(cmenergy - m_cm_energy) > m_cme_diff) {
         ATH_MSG_FATAL("Beam particles have incorrect energy: " << m_cm_energy/1000. << " GeV expected, vs. " << cmenergy/1000. << " GeV found");
         setFilterPassed(false);
         if (m_doHist){
@@ -526,7 +526,7 @@ StatusCode TestHepMC::execute() {
           negEnPart.push_back(pbarcode);
           ++m_negativeEnergyTachyonicCheckRate;
         }
-        const double aener = fabs(pmom.e());
+        const double aener = std::abs(pmom.e());
         if ( aener+m_accur_margin < std::abs(pmom.px()) || aener+m_accur_margin < std::abs(pmom.py()) || aener+m_accur_margin < std::abs(pmom.pz()) ) {
           tachyons.push_back(pbarcode);
           ++m_negativeEnergyTachyonicCheckRate;
@@ -601,7 +601,7 @@ StatusCode TestHepMC::execute() {
       /// @todo Persuade generator authors to set proper generated masses in HepMC, then *really* require mass = 0
       if (ppdgid == 22 && pstatus == 1) {
         const double mass = pitr->generated_mass();
-        if (fabs(mass) > 1.0) { // in MeV
+        if (std::abs(mass) > 1.0) { // in MeV
           ATH_MSG_WARNING("Photon with non-zero mass found! Mass: " << mass << " MeV, BARCODE=" << pbarcode);
           ++m_nonZeroPhotonMassCheckRate;
         }
@@ -619,7 +619,7 @@ StatusCode TestHepMC::execute() {
     } // End of check for interacting particles not known by G4
 
     // Energy balance
-    double lostE = fabs(totalE - cmenergy);
+    double lostE = std::abs(totalE - cmenergy);
     if (lostE > m_energy_diff) {
       ATH_MSG_WARNING("ENERGY BALANCE FAILED : E-difference = " << lostE << " MeV");
 
@@ -636,12 +636,12 @@ StatusCode TestHepMC::execute() {
     } // End of energy balance check
 
     // Momentum balance
-    if ( fabs(totalPx) > m_energy_diff || fabs(totalPy) > m_energy_diff || fabs(totalPz) > m_energy_diff ) {
+    if ( std::abs(totalPx) > m_energy_diff || std::abs(totalPy) > m_energy_diff || std::abs(totalPz) > m_energy_diff ) {
       ATH_MSG_WARNING("MOMENTUM BALANCE FAILED : SumPx = " << totalPx << " SumPy = " <<  totalPy << " SumPz = " <<  totalPz << " MeV");
       if (m_doHist){
-        m_h_momentumImbalance_px->Fill(fabs(totalPx)*1.E-03);
-        m_h_momentumImbalance_py->Fill(fabs(totalPy)*1.E-03);
-        m_h_momentumImbalance_pz->Fill(fabs(totalPz)*1.E-03);
+        m_h_momentumImbalance_px->Fill(std::abs(totalPx)*1.E-03);
+        m_h_momentumImbalance_py->Fill(std::abs(totalPy)*1.E-03);
+        m_h_momentumImbalance_pz->Fill(std::abs(totalPz)*1.E-03);
       }
       if (m_dumpEvent) HepMC::Print::line(std::cout,**itr);
       if (m_momImbalanceTest) {
diff --git a/Generators/EvtGen_i/src/EvtDecay.cxx b/Generators/EvtGen_i/src/EvtDecay.cxx
index 5d40740f8b5c534763c7d9acbe66b8f97b4c03f4..efd24a3e0962437e57353ec54760387c8a1f2d9a 100644
--- a/Generators/EvtGen_i/src/EvtDecay.cxx
+++ b/Generators/EvtGen_i/src/EvtDecay.cxx
@@ -183,7 +183,7 @@ StatusCode EvtDecay::callEvtGen( HepMC::GenEvent* hepMCevt ) {
 
 			EvtParticle* part=EvtParticleFactory::particleFactory(eid,p_init);
 
-			if(fabs(id)==5122 && m_PolarizedLambdab) setLambdabSpinDensityMatrix(part,m_LambdabPol);
+			if(std::abs(id)==5122 && m_PolarizedLambdab) setLambdabSpinDensityMatrix(part,m_LambdabPol);
 
 			m_myGen->generateDecay(part);
 			if ( log.level() <= MSG::DEBUG ) part->printTree();
diff --git a/Generators/EvtGen_i/src/EvtInclusiveDecay.cxx b/Generators/EvtGen_i/src/EvtInclusiveDecay.cxx
index 1cef870bcb653db1d4f766f6ba8c6eeb5c56b1fc..ed66103f0d02653681dc89864a2efb82c4a8157e 100644
--- a/Generators/EvtGen_i/src/EvtInclusiveDecay.cxx
+++ b/Generators/EvtGen_i/src/EvtInclusiveDecay.cxx
@@ -648,10 +648,10 @@ bool EvtInclusiveDecay::passesUserSelection(HepMC::GenEvent* hepMC) {
     for (auto muItr2 = muItr1+1; muItr2 != muons->end(); ++muItr2) {
       if( m_userSelRequireOppositeSignedMu && (*muItr1)->pdg_id() * (*muItr2)->pdg_id() > 0)
         continue;
-      if( !( (*muItr1)->momentum().perp() > m_userSelMu1MinPt && fabs((*muItr1)->momentum().pseudoRapidity()) < m_userSelMu1MaxEta && 
-             (*muItr2)->momentum().perp() > m_userSelMu2MinPt && fabs((*muItr2)->momentum().pseudoRapidity()) < m_userSelMu2MaxEta ) &&
-          !( (*muItr2)->momentum().perp() > m_userSelMu1MinPt && fabs((*muItr2)->momentum().pseudoRapidity()) < m_userSelMu1MaxEta && 
-             (*muItr1)->momentum().perp() > m_userSelMu2MinPt && fabs((*muItr1)->momentum().pseudoRapidity()) < m_userSelMu2MaxEta ) )
+      if( !( (*muItr1)->momentum().perp() > m_userSelMu1MinPt && std::abs((*muItr1)->momentum().pseudoRapidity()) < m_userSelMu1MaxEta && 
+             (*muItr2)->momentum().perp() > m_userSelMu2MinPt && std::abs((*muItr2)->momentum().pseudoRapidity()) < m_userSelMu2MaxEta ) &&
+          !( (*muItr2)->momentum().perp() > m_userSelMu1MinPt && std::abs((*muItr2)->momentum().pseudoRapidity()) < m_userSelMu1MaxEta && 
+             (*muItr1)->momentum().perp() > m_userSelMu2MinPt && std::abs((*muItr1)->momentum().pseudoRapidity()) < m_userSelMu2MaxEta ) )
         continue;
       double dimuMass = invMass((*muItr1),(*muItr2));
       if( !( dimuMass > m_userSelMinDimuMass && (dimuMass < m_userSelMaxDimuMass || m_userSelMaxDimuMass < 0.) ) )
diff --git a/Generators/EvtGen_i/src/EvtPhotosEngine.cxx b/Generators/EvtGen_i/src/EvtPhotosEngine.cxx
index 92818f2c28843b18e81c7aaed356ff738cb046b4..ceb15390b021802fbdfd38d9cb260d0b3936addb 100644
--- a/Generators/EvtGen_i/src/EvtPhotosEngine.cxx
+++ b/Generators/EvtGen_i/src/EvtPhotosEngine.cxx
@@ -179,7 +179,7 @@ bool EvtPhotosEngine::doDecay(EvtParticle* theMother) {
 	  // according to what Photos has modified. However, this will 
 	  // violate energy conservation (from what Photos has provided).
 	  double mass = daugParticle->mass();
-	  double energy = sqrt(mass*mass + px*px + py*py + pz*pz);
+	  double energy = std::sqrt(mass*mass + px*px + py*py + pz*pz);
 	  newP4.set(energy, px, py, pz);
 	  // Set the new four-momentum (FSR applied)
 	  daugParticle->setP4WithFSR(newP4);
@@ -189,7 +189,7 @@ bool EvtPhotosEngine::doDecay(EvtParticle* theMother) {
       } else {
 
 	// Extra photon particle. Setup the four-momentum object.
-	double energy = sqrt(_mPhoton*_mPhoton + px*px + py*py + pz*pz);
+	double energy = std::sqrt(_mPhoton*_mPhoton + px*px + py*py + pz*pz);
 	newP4.set(energy, px, py, pz);
 
 	// Create a new photon particle and add it to the list of daughters
diff --git a/Generators/FlowAfterburner/share/Plotting_Macros/DrawPlots.C b/Generators/FlowAfterburner/share/Plotting_Macros/DrawPlots.C
index a759cfce6a00832747ecdd13f5d89d1d73261d0d..7bfde86160b1aa1ed5d6e1c7e804f93f445da4f9 100644
--- a/Generators/FlowAfterburner/share/Plotting_Macros/DrawPlots.C
+++ b/Generators/FlowAfterburner/share/Plotting_Macros/DrawPlots.C
@@ -252,12 +252,12 @@ Double_t get_vn(Double_t *x, Double_t *par)
   if(ihar==2) return v2;
 
   if(ihar==3) {
-    float fb=0.97 +1.06*exp(-0.5*b*b/3.2/3.2);
-    return pow(fb*sqrt(v2),3);
+    float fb=0.97 +1.06*std::exp(-0.5*b*b/3.2/3.2);
+    return std::pow(fb*std::sqrt(v2),3);
   }
-  float gb= 1.096 +1.36 *exp(-0.5*b*b/3.0/3.0);
-  gb=gb*sqrt(v2);
-  return pow(gb,ihar);
+  float gb= 1.096 +1.36 *std::exp(-0.5*b*b/3.0/3.0);
+  gb=gb*std::sqrt(v2);
+  return std::pow(gb,ihar);
 }
 
 
@@ -281,8 +281,8 @@ profile_resolution->Write();
   
   for(int ihar=0;ihar<6;ihar++){
     double reso=profile_resolution->GetBinContent(ihar+1);
-    if (reso >=0) reso= sqrt( reso);
-    else          reso=-sqrt(-reso);
+    if (reso >=0) reso= std::sqrt( reso);
+    else          reso=-std::sqrt(-reso);
     for(int ieta=0;ieta<n_etabin;ieta++){
       sprintf(name,"profile_pt_dep_reco_%d_eta%d",ihar+1,ieta);
       prof=(TProfile*)Infile->Get(name);
diff --git a/Generators/FlowAfterburner/share/Plotting_Macros/DrawPlots_MB.C b/Generators/FlowAfterburner/share/Plotting_Macros/DrawPlots_MB.C
index ddfd15076349bb03be3564b156b3b1c0ed1f7fe7..77b71106f1f70adc921ea068ab4afa1be1acbb33 100644
--- a/Generators/FlowAfterburner/share/Plotting_Macros/DrawPlots_MB.C
+++ b/Generators/FlowAfterburner/share/Plotting_Macros/DrawPlots_MB.C
@@ -394,8 +394,8 @@ for(int ihar=0;ihar<6;ihar++){
 for(int ihar=0;ihar<6;ihar++){
   for(int ib_imp=0;ib_imp<n_b_bins;ib_imp++){
     double reso=profile_resolution[ihar]->GetBinContent(ib_imp+1);
-    if (reso >=0) reso= sqrt( reso);
-    else          reso=-sqrt(-reso);
+    if (reso >=0) reso= std::sqrt( reso);
+    else          reso=-std::sqrt(-reso);
 
     for(int ieta=0;ieta<n_etabin;ieta++){
       profile_pt_dep_reco [ihar][ib_imp][ieta]->Scale(1.0/reso);
diff --git a/Generators/FlowAfterburner/src/AddFlowByShifting.cxx b/Generators/FlowAfterburner/src/AddFlowByShifting.cxx
index 8deece141497b6f3c52f0b1fa70fab96110dfa04..b13cd775e762efd262bf3e66c9eb22e4320cc243 100644
--- a/Generators/FlowAfterburner/src/AddFlowByShifting.cxx
+++ b/Generators/FlowAfterburner/src/AddFlowByShifting.cxx
@@ -264,7 +264,7 @@ StatusCode AddFlowByShifting::execute() {
 
       //skip particle if eta is outside implementation range
       if(m_floweta_sw){
-        float eta=fabs(momentum.pseudoRapidity());
+        float eta=std::abs(momentum.pseudoRapidity());
         if (eta<m_flow_mineta || eta> m_flow_maxeta) continue;
       }
 
@@ -358,7 +358,7 @@ void AddFlowByShifting::MoveDescendantsToParent
       ATH_MSG_DEBUG("Processing vertex " << HepMC::barcode(descvtx));
 
       // rotate vertex
-      if(fabs(phishift) > 1e-7) {
+      if(std::abs(phishift) > 1e-7) {
 	CLHEP::HepLorentzVector position(descvtx->position().x(),
 				  descvtx->position().y(),
 				  descvtx->position().z(),
@@ -381,7 +381,7 @@ void AddFlowByShifting::MoveDescendantsToParent
 
 	m_particles_processed++;
 	// rotate particle
-	if(fabs(phishift) > 1e-7) {
+	if(std::abs(phishift) > 1e-7) {
 	  momentum.rotateZ(phishift*Gaudi::Units::rad);
 	  descpart->set_momentum( HepMC::FourVector(momentum.px(),momentum.py(),momentum.pz(),momentum.e()) );
    	  ATH_MSG_DEBUG(" Phi shift =   " << phishift<<
@@ -488,7 +488,7 @@ double AddFlowByShifting::AddFlowToParent (HepMC::GenParticlePtr parent, const H
     phishift = phi-phi_0;
   }
 
-  if(fabs(phishift) > 1e-7) {
+  if(std::abs(phishift) > 1e-7) {
     momentum.rotateZ(phishift*Gaudi::Units::rad);
     parent->set_momentum( HepMC::FourVector(momentum.px(),momentum.py(),momentum.pz(),momentum.e()) );
   }
diff --git a/Generators/FlowAfterburner/src/CheckFlow.cxx b/Generators/FlowAfterburner/src/CheckFlow.cxx
index 29c6db3e1c6b5278906a9d2761a1225552ccf058..cc3af1f4af077bd0d4555e3bddcaab833232fb20 100644
--- a/Generators/FlowAfterburner/src/CheckFlow.cxx
+++ b/Generators/FlowAfterburner/src/CheckFlow.cxx
@@ -221,8 +221,8 @@ StatusCode CheckFlow::execute() {
 	   << " Eta = " << rapid << "  Phi = " << phi 
 	   << " PhiR = " << phiR << endmsg;
     
-    if( (fabs(rapid) >= m_rapcut_min) && (fabs(rapid) <= m_rapcut_max) &&
-	(fabs(pt) >= m_ptcut_min) && (fabs(pt) <= m_ptcut_max) ) {
+    if( (std::abs(rapid) >= m_rapcut_min) && (std::abs(rapid) <= m_rapcut_max) &&
+	(std::abs(pt) >= m_ptcut_min) && (std::abs(pt) <= m_ptcut_max) ) {
       ngenerated++;
       m_phi->Fill(phi, 1.);
       double phi_corr = phi - phiR;
diff --git a/Generators/FlowAfterburner/src/CheckFlow_New.cxx b/Generators/FlowAfterburner/src/CheckFlow_New.cxx
index 9ea7fd0326a412231ffadf6a6340d074dbb629cd..087b4188d005b54de324977a45d93bfcb7857b71 100644
--- a/Generators/FlowAfterburner/src/CheckFlow_New.cxx
+++ b/Generators/FlowAfterburner/src/CheckFlow_New.cxx
@@ -295,13 +295,13 @@ StatusCode CheckFlow_New::execute() {
 	   << " PID = " << pid << " Status = " << p_stat
 	   << " Eta = " << rapid << "  Phi = " << phi<< endmsg;
 
-    if( (fabs(rapid) >= m_rapcut_min) && (fabs(rapid) <= m_rapcut_max) &&
-	(fabs(pt) >= m_ptcut_min) && (fabs(pt) <= m_ptcut_max) ) {
+    if( (std::abs(rapid) >= m_rapcut_min) && (std::abs(rapid) <= m_rapcut_max) &&
+	(std::abs(pt) >= m_ptcut_min) && (std::abs(pt) <= m_ptcut_max) ) {
 
       for(int ihar=0;ihar<6;ihar++){
         float temp=(ihar+1)*(phi-Psi_n[ihar]);
 
-        int ieta= (int)(fabs(rapid)*n_etabin/eta_bin_max);
+        int ieta= (int)(std::abs(rapid)*n_etabin/eta_bin_max);
         if(ieta>=0 && ieta<n_etabin) m_profile_pt_dep [ihar][ieta]->Fill(pt/1000,cos(temp));
 
 
diff --git a/Generators/FlowAfterburner/src/CheckFlow_New_Minbias.cxx b/Generators/FlowAfterburner/src/CheckFlow_New_Minbias.cxx
index 83e3266694a96e9a427533c8357a1db57d3ebe9b..daeb30c2f5390ab6abb4d4dc3c379c05792ed5d9 100644
--- a/Generators/FlowAfterburner/src/CheckFlow_New_Minbias.cxx
+++ b/Generators/FlowAfterburner/src/CheckFlow_New_Minbias.cxx
@@ -271,15 +271,15 @@ StatusCode CheckFlow_New_Minbias::execute() {
     ATH_MSG_DEBUG(" PID = " << pid   << " Status = " << p_stat \
 	       << " Eta = " << rapid << " Phi = "    << phi);
     
-    if( (fabs(rapid) >= m_rapcut_min) && 
-        (fabs(rapid) <= m_rapcut_max) &&
-	(fabs(pt)    >= m_ptcut_min ) &&
-        (fabs(pt)    <= m_ptcut_max)) {
+    if( (std::abs(rapid) >= m_rapcut_min) && 
+        (std::abs(rapid) <= m_rapcut_max) &&
+	(std::abs(pt)    >= m_ptcut_min ) &&
+        (std::abs(pt)    <= m_ptcut_max)) {
       
       for(int ihar=0;ihar<6;ihar++){
         float temp=(ihar+1)*(phi-Psi_n[ihar]);
 
-        int ieta= (int)(fabs(rapid)*n_etabin/eta_bin_max);
+        int ieta= (int)(std::abs(rapid)*n_etabin/eta_bin_max);
         if(ieta>=0 && ieta<n_etabin) m_profile_pt_dep [ihar][ib_imp][ieta]->Fill(pt/1000,cos(temp));
         
 
@@ -321,7 +321,7 @@ StatusCode CheckFlow_New_Minbias::execute() {
         sin_ID1[ihar]+=sin((ihar+1)*phi);
       } 
     }
-    if(fabs(pt)>=0){
+    if(std::abs(pt)>=0){
       tot_ID2++;
       for(int ihar=0;ihar<6;ihar++){
         cos_ID2[ihar]+=cos((ihar+1)*phi);
@@ -397,15 +397,15 @@ StatusCode CheckFlow_New_Minbias::execute() {
     double pt     = pitr->momentum().perp();
     double rapid  = pitr->momentum().pseudoRapidity();
     double phi    = pitr->momentum().phi();
-    if( (fabs(rapid) >= m_rapcut_min) && (fabs(rapid) <= m_rapcut_max) &&
-	(fabs(pt) >= m_ptcut_min) && (fabs(pt) <= m_ptcut_max) ) {
+    if( (std::abs(rapid) >= m_rapcut_min) && (std::abs(rapid) <= m_rapcut_max) &&
+	(std::abs(pt) >= m_ptcut_min) && (std::abs(pt) <= m_ptcut_max) ) {
       
       for(int ihar=0;ihar<6;ihar++){
         float       temp=(ihar+1)*(phi-Psi_n_reco_pos[ihar]);
         if(rapid>0) temp=(ihar+1)*(phi-Psi_n_reco_neg[ihar]);
 
 
-        int ieta= (int)(fabs(rapid)*n_etabin/eta_bin_max);
+        int ieta= (int)(std::abs(rapid)*n_etabin/eta_bin_max);
         if(ieta>=0 && ieta<n_etabin) m_profile_pt_dep_reco [ihar][ib_imp][ieta]->Fill(pt/1000,cos(temp));
 
         float temp_pt=pt/1000;
diff --git a/Generators/GenAnalysisTools/ReweightTools/src/PDFReweightTool.cxx b/Generators/GenAnalysisTools/ReweightTools/src/PDFReweightTool.cxx
index da5c680795dab48d7cc94d2548dd738ce2e47424..58a6b8b7bb6330faefeb8165d29282fbfbf24bb2 100644
--- a/Generators/GenAnalysisTools/ReweightTools/src/PDFReweightTool.cxx
+++ b/Generators/GenAnalysisTools/ReweightTools/src/PDFReweightTool.cxx
@@ -436,8 +436,8 @@ StatusCode PDFReweightTool::Reweight(HepMC::GenEvent* evt) {
 			//which is equal to
 			//	 (cvPDF_new(p1) * cvPDF_new(p2)) / (cvPDF_original(p1) * cvPDF_original(p2))  
 			else {
-				if (fabs(m_used_pdf1)>0.) m_weightFactor *= f1[fl1+6]/m_used_pdf1;
-				if (fabs(m_used_pdf2)>0.) m_weightFactor *= f2[fl2+6]/m_used_pdf2;
+				if (std::abs(m_used_pdf1)>0.) m_weightFactor *= f1[fl1+6]/m_used_pdf1;
+				if (std::abs(m_used_pdf2)>0.) m_weightFactor *= f2[fl2+6]/m_used_pdf2;
 
 				//and replace original PDF values
 				this->SetEventPDF1( f1[fl1+6] );
@@ -448,8 +448,8 @@ StatusCode PDFReweightTool::Reweight(HepMC::GenEvent* evt) {
 		
 		//calculate event weight at 'this' error PDF
 		double weight = m_weightFactor;
-		if (fabs(m_used_pdf1)>0.) weight *= f1[fl1+6]/m_used_pdf1;
-		if (fabs(m_used_pdf2)>0.) weight *= f2[fl2+6]/m_used_pdf2;
+		if (std::abs(m_used_pdf1)>0.) weight *= f1[fl1+6]/m_used_pdf1;
+		if (std::abs(m_used_pdf2)>0.) weight *= f2[fl2+6]/m_used_pdf2;
 
 		msg(MSG::DEBUG)  <<" weight = "
 				<< weight
diff --git a/Generators/GeneratorFilters/doc/GeneratorFilters.tex b/Generators/GeneratorFilters/doc/GeneratorFilters.tex
index 831579594cd143c1ca5598c174946b65769d390c..18622cee3aa337c11a38779cfdb23124c234f705 100644
--- a/Generators/GeneratorFilters/doc/GeneratorFilters.tex
+++ b/Generators/GeneratorFilters/doc/GeneratorFilters.tex
@@ -75,7 +75,7 @@ and rapidity are available.
         pitr!=genEvt->particles_end(); ++pitr ){
       if( ((*pitr)->pdg_id() == 11) || ((*pitr)->pdg_id() == -11) ){
         if( ((*pitr)->momentum().perp() >=m_Ptmin) && 
-            fabs((*pitr)->momentum().pseudoRapidity()) <=m_EtaRange){
+            std::abs((*pitr)->momentum().pseudoRapidity()) <=m_EtaRange){
           return StatusCode::SUCCESS;
         }
 \end{verbatim}
diff --git a/Generators/GeneratorFilters/src/ATauFilter.cxx b/Generators/GeneratorFilters/src/ATauFilter.cxx
index 8abfcf6c5c0ff28746e0d38a9fecf725f3b5020c..bc5e815579c2a4deb297fafc49f44ab9e745876d 100644
--- a/Generators/GeneratorFilters/src/ATauFilter.cxx
+++ b/Generators/GeneratorFilters/src/ATauFilter.cxx
@@ -169,7 +169,7 @@ StatusCode ATauFilter::filterEvent() {
          && ( std::abs( ataulep->momentum().pseudoRapidity() ) <= m_EtaRange ) ) {
       CLHEP::HepLorentzVector mom_taulep(taulep->momentum().px(), taulep->momentum().py(), taulep->momentum().pz(), taulep->momentum().e());
       CLHEP::HepLorentzVector mom_ataulep(ataulep->momentum().px(), ataulep->momentum().py(), ataulep->momentum().pz(), ataulep->momentum().e());
-      if ( fabs(mom_taulep.vect().deltaPhi(mom_ataulep.vect())) < m_maxdphi ) {
+      if ( std::abs(mom_taulep.vect().deltaPhi(mom_ataulep.vect())) < m_maxdphi ) {
         m_eventsllacc++;
         return StatusCode::SUCCESS;
       }
@@ -183,10 +183,10 @@ StatusCode ATauFilter::filterEvent() {
     if ( ( ( ( taulep->momentum().perp() >= m_lhPtmine ) && ( taulep->pdg_id() == 11 ) )
            || ( ( taulep->momentum().perp() >= m_lhPtminmu ) && ( taulep->pdg_id() == 13 ) ) )
          && ( mom_atauprod.perp() >= m_lhPtminh )
-         && ( fabs( taulep->momentum().pseudoRapidity() ) <= m_EtaRange )
-         && ( fabs( mom_atauprod.pseudoRapidity() ) <= m_EtaRange ) ) {
+         && ( std::abs( taulep->momentum().pseudoRapidity() ) <= m_EtaRange )
+         && ( std::abs( mom_atauprod.pseudoRapidity() ) <= m_EtaRange ) ) {
       CLHEP::HepLorentzVector mom_taulep(taulep->momentum().px(), taulep->momentum().py(), taulep->momentum().pz(), taulep->momentum().e());
-      if ( fabs(mom_taulep.vect().deltaPhi(mom_atauprod.vect())) < m_maxdphi ) {
+      if ( std::abs(mom_taulep.vect().deltaPhi(mom_atauprod.vect())) < m_maxdphi ) {
         m_eventslhacc++;
         return StatusCode::SUCCESS;
       }
@@ -220,7 +220,7 @@ StatusCode ATauFilter::filterEvent() {
          && ( mom_atauprod.perp() >= m_hhPtmin )
          && ( std::abs( mom_tauprod.pseudoRapidity() ) <= m_EtaRange )            // check eta-range
          && ( std::abs( mom_atauprod.pseudoRapidity() ) <= m_EtaRange ) ) {
-      if ( fabs(mom_atauprod.vect().deltaPhi(mom_tauprod.vect())) < m_maxdphi ) {
+      if ( std::abs(mom_atauprod.vect().deltaPhi(mom_tauprod.vect())) < m_maxdphi ) {
         m_eventshhacc++;
         m_nPass++;
         return StatusCode::SUCCESS;
diff --git a/Generators/GeneratorFilters/src/AsymJetFilter.cxx b/Generators/GeneratorFilters/src/AsymJetFilter.cxx
index 2a55f558044016940d1e55c13ad2a7a408348322..c1558ab2a4e4624da0cd08991733d71bae8438e8 100644
--- a/Generators/GeneratorFilters/src/AsymJetFilter.cxx
+++ b/Generators/GeneratorFilters/src/AsymJetFilter.cxx
@@ -227,7 +227,7 @@ StatusCode AsymJetFilter::filterEvent() {
       FoundJet.setPy(jetpy);
       FoundJet.setPz(jetpz);
       FoundJet.setE(jete);
-      if (fabs(FoundJet.pseudoRapidity()) < m_UserEta) {
+      if (std::abs(FoundJet.pseudoRapidity()) < m_UserEta) {
         m_Jets.push_back(FoundJet);   //OK we found one. add it to the list  if its inside the eta region
       }
     }
diff --git a/Generators/GeneratorFilters/src/BSignalFilter.cxx b/Generators/GeneratorFilters/src/BSignalFilter.cxx
index 0b02b70cf50475551028b469016907612b5af1f5..01def0f4ab2cd27936870b8f019c3b9ae2ebf15b 100644
--- a/Generators/GeneratorFilters/src/BSignalFilter.cxx
+++ b/Generators/GeneratorFilters/src/BSignalFilter.cxx
@@ -360,7 +360,7 @@ StatusCode BSignalFilter::filterEvent()
 bool BSignalFilter::test_cuts(const double myPT, const double testPT,
 			      const double myEta, const double testEta) const
 {
-  return ( (myPT >= testPT) && (fabs(myEta) <= testEta) );
+  return ( (myPT >= testPT) && (std::abs(myEta) <= testEta) );
 }
 
 
diff --git a/Generators/GeneratorFilters/src/BSubstruct.cxx b/Generators/GeneratorFilters/src/BSubstruct.cxx
index c9be0a7f0e957fe3c8b413de39842dbce32b3ff3..13cd4b835007efa329222b7f2cbf42ed62c990da 100644
--- a/Generators/GeneratorFilters/src/BSubstruct.cxx
+++ b/Generators/GeneratorFilters/src/BSubstruct.cxx
@@ -49,7 +49,7 @@ inline bool BSubstruct::hasCBQuark(int pdgID) const {
 
 
 inline double BSubstruct::deltaPhi(double phi1, double phi2) const {
-  double dPhi = fabs(fmod(phi1 - phi2, 2*M_PI));
+  double dPhi = std::abs(fmod(phi1 - phi2, 2*M_PI));
   if (dPhi > M_PI) {
     dPhi = 2*M_PI - dPhi;
   }
diff --git a/Generators/GeneratorFilters/src/Boosted2DijetFilter.cxx b/Generators/GeneratorFilters/src/Boosted2DijetFilter.cxx
index 1b6717e636e42c5b2ca74972e12aba51e885068f..33fd57cb59a8d35edef7d4b07a0f3ff1434bf63a 100644
--- a/Generators/GeneratorFilters/src/Boosted2DijetFilter.cxx
+++ b/Generators/GeneratorFilters/src/Boosted2DijetFilter.cxx
@@ -108,14 +108,14 @@ StatusCode Boosted2DijetFilter::filterEvent() {
   //getting a collection of truth jets which pass some cuts 
   for (jitr = (*truthjetTES).begin(); jitr !=(*truthjetTES).end(); ++jitr) { 
     if( (*jitr)->pt() < m_jetPtMin ) continue;
-    if( fabs( (*jitr)->eta() ) > m_jetEtaMax ) continue;
+    if( std::abs( (*jitr)->eta() ) > m_jetEtaMax ) continue;
     jets.push_back(jitr);
   }
 
   //getting the akt8 truth jets 
   for (jitr_akt8 = (*truthjetTES_akt8).begin(); jitr_akt8 !=(*truthjetTES_akt8).end(); ++jitr_akt8) { 
     if( (*jitr_akt8)->pt() < m_akt8PtMin ) continue;
-    if( fabs( (*jitr_akt8)->eta() ) > m_jetEtaMax ) continue;
+    if( std::abs( (*jitr_akt8)->eta() ) > m_jetEtaMax ) continue;
     jets_akt8.push_back(jitr_akt8);
   }
   
diff --git a/Generators/GeneratorFilters/src/BoostedHadTopAndTopPair.cxx b/Generators/GeneratorFilters/src/BoostedHadTopAndTopPair.cxx
index 14ceaf9977d38c3e2425f8c9b917866d3de755b4..27d4df28ce55d1c710f0d465953ef9d83f734e28 100644
--- a/Generators/GeneratorFilters/src/BoostedHadTopAndTopPair.cxx
+++ b/Generators/GeneratorFilters/src/BoostedHadTopAndTopPair.cxx
@@ -78,8 +78,8 @@ StatusCode BoostedHadTopAndTopPair::filterEvent() {
     } // particle loop
   } // event loop
 
-  double pTPairList = sqrt( pow( topListMomentum.px() + topbListMomentum.px() , 2 ) + pow( topListMomentum.py() + topbListMomentum.py() , 2 )); 
-  double pTPairChildren = sqrt( pow( topChildrenMomentum.px() + topbChildrenMomentum.px() , 2 ) + pow( topChildrenMomentum.py() + topbChildrenMomentum.py() , 2 )); 
+  double pTPairList = std::sqrt( std::pow( topListMomentum.px() + topbListMomentum.px() , 2 ) + std::pow( topListMomentum.py() + topbListMomentum.py() , 2 )); 
+  double pTPairChildren = std::sqrt( std::pow( topChildrenMomentum.px() + topbChildrenMomentum.px() , 2 ) + std::pow( topChildrenMomentum.py() + topbChildrenMomentum.py() , 2 )); 
 
   if (m_cutPtOf == 0){ // cut on the pT of top on the truth list
     if (pTHadTopList   >= m_tHadPtMin    &&   pTHadTopList   < m_tHadPtMax  )  passTopHad  = true;
diff --git a/Generators/GeneratorFilters/src/ChargedTracksFilter.cxx b/Generators/GeneratorFilters/src/ChargedTracksFilter.cxx
index 703ebf8eb836365e2e1de6ea46441df30294e453..47d5a02953c990cac9492bf107a6857d6bd4d1f6 100644
--- a/Generators/GeneratorFilters/src/ChargedTracksFilter.cxx
+++ b/Generators/GeneratorFilters/src/ChargedTracksFilter.cxx
@@ -34,7 +34,7 @@ StatusCode ChargedTracksFilter::filterEvent() {
       // Count tracks in specified acceptance
       const double pT = part->momentum().perp();
       const double eta = part->momentum().pseudoRapidity();
-      if (pT >= m_Ptmin && fabs(eta) <= m_EtaRange && pCharge != 0) {
+      if (pT >= m_Ptmin && std::abs(eta) <= m_EtaRange && pCharge != 0) {
         ATH_MSG_DEBUG("Found particle, " <<
                       " pT = " << pT <<
                       " eta = " << eta <<
diff --git a/Generators/GeneratorFilters/src/DecayLengthFilter.cxx b/Generators/GeneratorFilters/src/DecayLengthFilter.cxx
index 292fe5f50a2607d75c6a06e1658168855ec9ad84..c6effd523b671982beff0c1947bc931d4d0ec25e 100644
--- a/Generators/GeneratorFilters/src/DecayLengthFilter.cxx
+++ b/Generators/GeneratorFilters/src/DecayLengthFilter.cxx
@@ -106,6 +106,6 @@ StatusCode DecayLengthFilter::filterEvent() {
 
 
 bool DecayLengthFilter::isAccepted(float distR, float distZ) {
-  return ( (fabs(distZ)>m_Zmin && fabs(distZ)<m_Zmax && distR<m_Rmax) ||  // endcaps
-           (distR>m_Rmin && distR<m_Rmax && fabs(distZ)<m_Zmax) );  // barrel
+  return ( (std::abs(distZ)>m_Zmin && std::abs(distZ)<m_Zmax && distR<m_Rmax) ||  // endcaps
+           (distR>m_Rmin && distR<m_Rmax && std::abs(distZ)<m_Zmax) );  // barrel
 }
diff --git a/Generators/GeneratorFilters/src/DiBjetFilter.cxx b/Generators/GeneratorFilters/src/DiBjetFilter.cxx
index 1d4790fac8ea111e8f308dd26cb09b452dcf452f..65929f92ab50be299912a3895e0dd3c0aa3eccf9 100644
--- a/Generators/GeneratorFilters/src/DiBjetFilter.cxx
+++ b/Generators/GeneratorFilters/src/DiBjetFilter.cxx
@@ -114,7 +114,7 @@ StatusCode DiBjetFilter::filterEvent() {
        lead_jet_pt = (*jitr)->pt();
     }
     if( (*jitr)->pt() < m_jetPtMin ) continue;
-    if( fabs( (*jitr)->eta() ) > m_jetEtaMax ) continue;
+    if( std::abs( (*jitr)->eta() ) > m_jetEtaMax ) continue;
     jets.push_back(jitr);
   }
 
diff --git a/Generators/GeneratorFilters/src/DiLeptonMassFilter.cxx b/Generators/GeneratorFilters/src/DiLeptonMassFilter.cxx
index 86b09733151760fc2a38d0fbb658fba02b654192..392a484681b135381eae90bf5fe151aa25e735b4 100644
--- a/Generators/GeneratorFilters/src/DiLeptonMassFilter.cxx
+++ b/Generators/GeneratorFilters/src/DiLeptonMassFilter.cxx
@@ -41,7 +41,7 @@ StatusCode DiLeptonMassFilter::filterEvent() {
 
       // Pick electrons or muons with Pt > m_inPt and |eta| < m_maxEta
       if (abs(pdgId1) == 11 || abs(pdgId1) == 13) {
-        if ((*pitr1)->momentum().perp() >= m_minPt && fabs((*pitr1)->momentum().pseudoRapidity()) <= m_maxEta){
+        if ((*pitr1)->momentum().perp() >= m_minPt && std::abs((*pitr1)->momentum().pseudoRapidity()) <= m_maxEta){
 
           // Loop over all remaining particles in the event
           auto pitr2 = pitr1;
@@ -57,7 +57,7 @@ StatusCode DiLeptonMassFilter::filterEvent() {
             // If m_allowElecMu is true allow also Z -> emu compinations (with charge requirements as above)
             if ((m_allowSameCharge  && (abs(pdgId2) == abs(pdgId1) || (m_allowElecMu && (abs(pdgId2) == 11 || abs(pdgId2) == 13) ) ) ) ||
                 (!m_allowSameCharge && (pdgId2 == -1*pdgId1 || (m_allowElecMu && (pdgId2 == (pdgId1 < 0 ? 1 : -1) * 11 || (pdgId1 < 0 ? 1 : -1) * pdgId2 == 13) ) ) ) ) {
-              if ((*pitr2)->momentum().perp() >= m_minPt && fabs((*pitr2)->momentum().pseudoRapidity()) <= m_maxEta){
+              if ((*pitr2)->momentum().perp() >= m_minPt && std::abs((*pitr2)->momentum().pseudoRapidity()) <= m_maxEta){
 
                 // Calculate invariant mass and apply cut
                 HepMC::FourVector vec((*pitr1)->momentum().px() + (*pitr2)->momentum().px(),
diff --git a/Generators/GeneratorFilters/src/DiPhotonFilter.cxx b/Generators/GeneratorFilters/src/DiPhotonFilter.cxx
index 2c3d5b1812306b86760b1e3c549f7223bb7cc1ac..b3a3d55b36abc7e82bbca13919d1efb1e973e939 100644
--- a/Generators/GeneratorFilters/src/DiPhotonFilter.cxx
+++ b/Generators/GeneratorFilters/src/DiPhotonFilter.cxx
@@ -93,7 +93,7 @@ StatusCode DiPhotonFilter::filterEvent() {
         etamax = m_EtaRange_2nd;
       }
       if (MCTruthPhotonList[i]->momentum().perp() >= ptmin &&
-          fabs(MCTruthPhotonList[i]->momentum().pseudoRapidity()) <= etamax) {
+          std::abs(MCTruthPhotonList[i]->momentum().pseudoRapidity()) <= etamax) {
         MCTruthPhotonList2.push_back(MCTruthPhotonList[i]);
       }
     }
diff --git a/Generators/GeneratorFilters/src/DirectPhotonFilter.cxx b/Generators/GeneratorFilters/src/DirectPhotonFilter.cxx
index 6854950ad8b0969c03493660487d86281b5d5b23..da1d530584a3bc1e19fccc98a475622775776e36 100644
--- a/Generators/GeneratorFilters/src/DirectPhotonFilter.cxx
+++ b/Generators/GeneratorFilters/src/DirectPhotonFilter.cxx
@@ -93,7 +93,7 @@ StatusCode DirectPhotonFilter::filterEvent() {
     for (HepMC::GenEvent::particle_const_iterator pitr=genEvt->particles_begin(); pitr!=genEvt->particles_end(); ++pitr) {
       if (((*pitr)->pdg_id() == 22)) {
 	if( ((*pitr)->momentum().perp() >= m_Ptmin) && ((*pitr)->momentum().perp() <= m_Ptmax) &&
-	    fabs((*pitr)->momentum().pseudoRapidity()) <= m_EtaRange){
+	    std::abs((*pitr)->momentum().pseudoRapidity()) <= m_EtaRange){
 	  ATH_MSG_DEBUG("Generic photon found with status = " << (*pitr)->status() << " " << (*pitr)->barcode());
 
           HepMC::GenVertex* CandProdVertex = (*pitr)->production_vertex();
@@ -120,7 +120,7 @@ StatusCode DirectPhotonFilter::filterEvent() {
       if ( ((*pitr)->pdg_id() == 22) ){ 
 	if( (*pitr)->status() == 1 &&
 	    ((*pitr)->momentum().perp() >= m_Ptmin) && ((*pitr)->momentum().perp() <= m_Ptmax) &&
-	    fabs((*pitr)->momentum().pseudoRapidity()) <= m_EtaRange){
+	    std::abs((*pitr)->momentum().pseudoRapidity()) <= m_EtaRange){
 
           // The following lines are for cross checking purpose when using different generators
           HepMC::GenVertex* CandProdVertex = (*pitr)->production_vertex();
diff --git a/Generators/GeneratorFilters/src/DstD0K3piFilter.cxx b/Generators/GeneratorFilters/src/DstD0K3piFilter.cxx
index 9e97570368993de111f71bbb30ea3d7f9eaf0995..4c086ac70e359e27a4ff1b55327367772db5cf7f 100644
--- a/Generators/GeneratorFilters/src/DstD0K3piFilter.cxx
+++ b/Generators/GeneratorFilters/src/DstD0K3piFilter.cxx
@@ -96,7 +96,7 @@ StatusCode DstD0K3piFilter::filterEvent() {
       // Work only with D*
       if (std::abs((*pitr)->pdg_id()) != 413) continue; // D*+
       if ((*pitr)->momentum().perp() < m_Ptmin) continue;
-      if (fabs((*pitr)->momentum().pseudoRapidity()) > m_EtaRange) continue;
+      if (std::abs((*pitr)->momentum().pseudoRapidity()) > m_EtaRange) continue;
 
       int nDstChild = 0;
       HepMC::GenParticle* mcpartDst = *pitr;
diff --git a/Generators/GeneratorFilters/src/ElectronFilter.cxx b/Generators/GeneratorFilters/src/ElectronFilter.cxx
index 5f8f65f194a7482f7102cd4ed5479cbeb4401579..208248253216ae5d154ab7e3a0c5751d09a4f9f8 100644
--- a/Generators/GeneratorFilters/src/ElectronFilter.cxx
+++ b/Generators/GeneratorFilters/src/ElectronFilter.cxx
@@ -18,7 +18,7 @@ StatusCode ElectronFilter::filterEvent() {
     const HepMC::GenEvent* genEvt = *itr;
     for (auto part: *genEvt) {
       if (part->status() == 1 && abs(part->pdg_id()) == 11) { // electron
-        if (part->momentum().perp() >= m_Ptmin && fabs(part->momentum().pseudoRapidity()) <= m_EtaRange) {
+        if (part->momentum().perp() >= m_Ptmin && std::abs(part->momentum().pseudoRapidity()) <= m_EtaRange) {
           return StatusCode::SUCCESS;
         }
       }
diff --git a/Generators/GeneratorFilters/src/FourLeptonInvMassFilter.cxx b/Generators/GeneratorFilters/src/FourLeptonInvMassFilter.cxx
index f70572cd14c4b0b0245364d05cab354a13852a2e..829e9cb0a5302f1cd3056ae92f5c5b2d5b736097 100644
--- a/Generators/GeneratorFilters/src/FourLeptonInvMassFilter.cxx
+++ b/Generators/GeneratorFilters/src/FourLeptonInvMassFilter.cxx
@@ -45,7 +45,7 @@ StatusCode FourLeptonInvMassFilter::filterEvent() {
       // Pick electrons or muons with Pt > m_inPt and |eta| < m_maxEta
       int pdgId1((*pitr1)->pdg_id());
       if (!(abs(pdgId1) == 11 || abs(pdgId1) == 13)) continue;	  
-      if (!((*pitr1)->momentum().perp() >= m_minPt && fabs((*pitr1)->momentum().pseudoRapidity()) <= m_maxEta)) continue;
+      if (!((*pitr1)->momentum().perp() >= m_minPt && std::abs((*pitr1)->momentum().pseudoRapidity()) <= m_maxEta)) continue;
       
       // Loop over all remaining particles in the event
       auto pitr2 = pitr1;
@@ -57,7 +57,7 @@ StatusCode FourLeptonInvMassFilter::filterEvent() {
 	// Pick electrons or muons with Pt > m_inPt and |eta| < m_maxEta	  
 	int pdgId2((*pitr2)->pdg_id());
 	if (!(abs(pdgId2) == 11 || abs(pdgId2) == 13)) continue;	     
-	if (!((*pitr2)->momentum().perp() >= m_minPt && fabs((*pitr2)->momentum().pseudoRapidity()) <= m_maxEta)) continue;
+	if (!((*pitr2)->momentum().perp() >= m_minPt && std::abs((*pitr2)->momentum().pseudoRapidity()) <= m_maxEta)) continue;
 	
 	// Loop over all remaining particles in the event
 	auto pitr3 = pitr2;
@@ -69,7 +69,7 @@ StatusCode FourLeptonInvMassFilter::filterEvent() {
 	  // Pick electrons or muons with Pt > m_inPt and |eta| < m_maxEta	  	      
 	  int pdgId3((*pitr3)->pdg_id());
 	  if (!(abs(pdgId3) == 11 || abs(pdgId3) == 13)) continue;	    
-	  if (!((*pitr3)->momentum().perp() >= m_minPt && fabs((*pitr3)->momentum().pseudoRapidity()) <= m_maxEta)) continue;
+	  if (!((*pitr3)->momentum().perp() >= m_minPt && std::abs((*pitr3)->momentum().pseudoRapidity()) <= m_maxEta)) continue;
 	  
 	  // Loop over all remaining particles in the event
 	  auto pitr4 = pitr3;
@@ -81,7 +81,7 @@ StatusCode FourLeptonInvMassFilter::filterEvent() {
 	    // Pick electrons or muons with Pt > m_inPt and |eta| < m_maxEta	  	      
 	    int pdgId4((*pitr4)->pdg_id());
 	    if (!(abs(pdgId4) == 11 || abs(pdgId4) == 13)) continue;	    
-	    if (!((*pitr4)->momentum().perp() >= m_minPt && fabs((*pitr4)->momentum().pseudoRapidity()) <= m_maxEta)) continue;
+	    if (!((*pitr4)->momentum().perp() >= m_minPt && std::abs((*pitr4)->momentum().pseudoRapidity()) <= m_maxEta)) continue;
 	    
 	    // 4lepton vector
 	    HepMC::FourVector vec((*pitr1)->momentum().px() + (*pitr2)->momentum().px() + (*pitr3)->momentum().px() + (*pitr4)->momentum().px(),
diff --git a/Generators/GeneratorFilters/src/FourLeptonMassFilter.cxx b/Generators/GeneratorFilters/src/FourLeptonMassFilter.cxx
index 39e8afba9d6b6c5cdc92deb63d71b03eae603beb..e7cf205ca5bb97f9a5b63555b10e1a7459e2de6f 100644
--- a/Generators/GeneratorFilters/src/FourLeptonMassFilter.cxx
+++ b/Generators/GeneratorFilters/src/FourLeptonMassFilter.cxx
@@ -44,7 +44,7 @@ StatusCode FourLeptonMassFilter::filterEvent() {
 	  // Pick electrons or muons with Pt > m_inPt and |eta| < m_maxEta
 	  int pdgId1((*pitr1)->pdg_id());
 	  if (!(abs(pdgId1) == 11 || abs(pdgId1) == 13)) continue;
-	  if (!((*pitr1)->momentum().perp() >= m_minPt && fabs((*pitr1)->momentum().pseudoRapidity()) <= m_maxEta)) continue;
+	  if (!((*pitr1)->momentum().perp() >= m_minPt && std::abs((*pitr1)->momentum().pseudoRapidity()) <= m_maxEta)) continue;
 
 	  // Loop over all remaining particles in the event
 	  auto pitr2 = pitr1;
@@ -55,7 +55,7 @@ StatusCode FourLeptonMassFilter::filterEvent() {
         // Pick electrons or muons with Pt > m_inPt and |eta| < m_maxEta
         int pdgId2((*pitr2)->pdg_id());
         if (!(abs(pdgId2) == 11 || abs(pdgId2) == 13)) continue;
-        if (!((*pitr2)->momentum().perp() >= m_minPt && fabs((*pitr2)->momentum().pseudoRapidity()) <= m_maxEta)) continue;
+        if (!((*pitr2)->momentum().perp() >= m_minPt && std::abs((*pitr2)->momentum().pseudoRapidity()) <= m_maxEta)) continue;
 
         // Loop over all remaining particles in the event
         auto pitr3 = pitr2;
@@ -66,8 +66,8 @@ StatusCode FourLeptonMassFilter::filterEvent() {
 
 		  // Pick electrons or muons with Pt > m_inPt and |eta| < m_maxEta
 		  int pdgId3((*pitr3)->pdg_id());
-		  if (!(abs(pdgId3) == 11 || abs(pdgId3) == 13)) continue;
-		  if (!((*pitr3)->momentum().perp() >= m_minPt && fabs((*pitr3)->momentum().pseudoRapidity()) <= m_maxEta)) continue;
+		  if (!(std::abs(pdgId3) == 11 || std::abs(pdgId3) == 13)) continue;
+		  if (!((*pitr3)->momentum().perp() >= m_minPt && std::abs((*pitr3)->momentum().pseudoRapidity()) <= m_maxEta)) continue;
 
           // Loop over all remaining particles in the event
 		  auto pitr4 = pitr3;
@@ -79,7 +79,7 @@ StatusCode FourLeptonMassFilter::filterEvent() {
             // Pick electrons or muons with Pt > m_inPt and |eta| < m_maxEta
             int pdgId4((*pitr4)->pdg_id());
             if (!(abs(pdgId4) == 11 || abs(pdgId4) == 13)) continue;
-            if (!((*pitr4)->momentum().perp() >= m_minPt && fabs((*pitr4)->momentum().pseudoRapidity()) <= m_maxEta)) continue;
+            if (!((*pitr4)->momentum().perp() >= m_minPt && std::abs((*pitr4)->momentum().pseudoRapidity()) <= m_maxEta)) continue;
 
             decltype(pitr1) apitr[4] = {pitr1,pitr2,pitr3,pitr4};
             int pdgIds[4]={pdgId1,pdgId2,pdgId3,pdgId4};
diff --git a/Generators/GeneratorFilters/src/GapJetFilter.cxx b/Generators/GeneratorFilters/src/GapJetFilter.cxx
index 76d0ccb601dbf9b2699f2a6c08231a0dcde02237..53eb86942f1e19a9b95d4ba403df7aeeb99e5fbd 100644
--- a/Generators/GeneratorFilters/src/GapJetFilter.cxx
+++ b/Generators/GeneratorFilters/src/GapJetFilter.cxx
@@ -261,11 +261,11 @@ GapJetFilter::filterEvent()
     }
   
           float rapgap_cl=-100.; 
-       if (fabs(cl_maxeta)<fabs(cl_mineta) && Clustag==1) {
+       if (std::abs(cl_maxeta)<std::abs(cl_mineta) && Clustag==1) {
          rapgap_cl = 4.9 - cl_maxeta;
        }
 
-       else if (fabs(cl_maxeta)>fabs(cl_mineta) && Clustag==1) {
+       else if (std::abs(cl_maxeta)>std::abs(cl_mineta) && Clustag==1) {
          rapgap_cl = 4.9 + cl_mineta;
        }
 
diff --git a/Generators/GeneratorFilters/src/HTFilter.cxx b/Generators/GeneratorFilters/src/HTFilter.cxx
index 8f161fd3db6ae97e409cdc807241ee464c4e698c..c5a168e0af91422b97c2044e7b7b67127013138a 100644
--- a/Generators/GeneratorFilters/src/HTFilter.cxx
+++ b/Generators/GeneratorFilters/src/HTFilter.cxx
@@ -89,7 +89,7 @@ StatusCode HTFilter::filterEvent() {
   double HT = -1;
   for (xAOD::JetContainer::const_iterator it_truth = (*truthjetTES).begin(); it_truth != (*truthjetTES).end() ; ++it_truth) {
     if (!(*it_truth)) continue;
-    if ( (*it_truth)->pt()>m_MinJetPt*CLHEP::GeV && fabs((*it_truth)->eta())<m_MaxJetEta ) {
+    if ( (*it_truth)->pt()>m_MinJetPt*CLHEP::GeV && std::abs((*it_truth)->eta())<m_MaxJetEta ) {
       ATH_MSG_VERBOSE("Adding truth jet with pt " << (*it_truth)->pt()
 		      << ", eta " << (*it_truth)->eta()
 		      << ", phi " << (*it_truth)->phi()
diff --git a/Generators/GeneratorFilters/src/HeavyFlavorHadronFilter.cxx b/Generators/GeneratorFilters/src/HeavyFlavorHadronFilter.cxx
index a258095fa6308f0e932eeabc871bcff4c49db766..48d368aafa2cd38901117ba91f29b99edcd7fa77 100644
--- a/Generators/GeneratorFilters/src/HeavyFlavorHadronFilter.cxx
+++ b/Generators/GeneratorFilters/src/HeavyFlavorHadronFilter.cxx
@@ -78,7 +78,7 @@ StatusCode HeavyFlavorHadronFilter::filterEvent() {
     const xAOD::JetContainer* truthjetTES;
     CHECK(evtStore()->retrieve( truthjetTES, m_TruthJetContainerName));
     for (xAOD::JetContainer::const_iterator j = truthjetTES->begin(); j != truthjetTES->end() ; ++j) {
-      if ((*j)->pt() > m_jetPtMin && fabs((*j)->eta()) < m_jetEtaMax) {
+      if ((*j)->pt() > m_jetPtMin && std::abs((*j)->eta()) < m_jetEtaMax) {
         jets.push_back(j);
       }
     }
@@ -99,7 +99,7 @@ StatusCode HeavyFlavorHadronFilter::filterEvent() {
       // of heavy flavor quarks!
       if (m_Request_bQuark && std::abs(part->pdg_id())==5 &&
           part->momentum().perp()>m_bPtMin &&
-          fabs(part->momentum().pseudoRapidity())<m_bEtaMax) {
+          std::abs(part->momentum().pseudoRapidity())<m_bEtaMax) {
         if (m_RequireTruthJet) {
           HepMC::FourVector tmp = part->momentum();
           TLorentzVector genpart(tmp.x(), tmp.y(), tmp.z(), tmp.t());
@@ -121,7 +121,7 @@ StatusCode HeavyFlavorHadronFilter::filterEvent() {
       if (m_Request_cQuark &&
           std::abs(part->pdg_id())==4 &&
           part->momentum().perp()>m_cPtMin &&
-          fabs(part->momentum().pseudoRapidity())<m_cEtaMax) {
+          std::abs(part->momentum().pseudoRapidity())<m_cEtaMax) {
         if (m_RequireTruthJet) {
           HepMC::FourVector tmp = part->momentum();
           TLorentzVector genpart(tmp.x(), tmp.y(), tmp.z(), tmp.t());
@@ -139,7 +139,7 @@ StatusCode HeavyFlavorHadronFilter::filterEvent() {
       if (m_RequestBottom &&
           isBwithWeakDK(part->pdg_id()) &&
           part->momentum().perp()>m_bottomPtMin &&
-          fabs(part->momentum().pseudoRapidity())<m_bottomEtaMax) {
+          std::abs(part->momentum().pseudoRapidity())<m_bottomEtaMax) {
         if (m_RequireTruthJet) {
           HepMC::FourVector tmp = part->momentum();
           TLorentzVector genpart(tmp.x(), tmp.y(), tmp.z(), tmp.t());
@@ -157,7 +157,7 @@ StatusCode HeavyFlavorHadronFilter::filterEvent() {
       if (m_RequestCharm &&
           isDwithWeakDK(part->pdg_id()) &&
           part->momentum().perp()>m_charmPtMin &&
-          fabs(part->momentum().pseudoRapidity())<m_charmEtaMax) {
+          std::abs(part->momentum().pseudoRapidity())<m_charmEtaMax) {
         if (m_RequireTruthJet) {
           HepMC::FourVector tmp = part->momentum();
           TLorentzVector genpart(tmp.x(), tmp.y(), tmp.z(), tmp.t());
@@ -176,7 +176,7 @@ StatusCode HeavyFlavorHadronFilter::filterEvent() {
         (part->pdg_id() == m_PDGID ||
          (m_PDGAntiParticleToo && std::abs(part->pdg_id()) == m_PDGID));
       if (pdgok && part->momentum().perp() > m_PDGPtMin &&
-          fabs(part->momentum().pseudoRapidity()) < m_PDGEtaMax) {
+          std::abs(part->momentum().pseudoRapidity()) < m_PDGEtaMax) {
         if (m_RequireTruthJet) {
           HepMC::FourVector tmp = part->momentum();
           TLorentzVector genpart(tmp.x(), tmp.y(), tmp.z(), tmp.t());
diff --git a/Generators/GeneratorFilters/src/JetFilter.cxx b/Generators/GeneratorFilters/src/JetFilter.cxx
index 3951a7a25b46a3d185952a1614b4b2b0e756bf34..b6be98a4cef3e910980975da21a6818c2f450e87 100644
--- a/Generators/GeneratorFilters/src/JetFilter.cxx
+++ b/Generators/GeneratorFilters/src/JetFilter.cxx
@@ -86,7 +86,7 @@ StatusCode JetFilter::filterEvent() {
            (part->pdg_id() != 12 ) && (part->pdg_id() != -12 ) &&
            (part->pdg_id() != 14 ) && (part->pdg_id() != -14 ) &&
            (part->pdg_id() != 16 ) && (part->pdg_id() != -16 ) &&
-           (fabs(part->momentum().pseudoRapidity()) <= m_emaxeta) ) { // no neutrinos or muons and particles must be in active range
+           (std::abs(part->momentum().pseudoRapidity()) <= m_emaxeta) ) { // no neutrinos or muons and particles must be in active range
         int ip, ie;
         ip = (int) ((m_twopi/2.+ part->momentum().phi())/m_edphi); //phi is in range -CLHEP::pi to CLHEP::pi
         ie = (int) ((part->momentum().pseudoRapidity()+m_emaxeta)/m_edeta);
@@ -201,7 +201,7 @@ StatusCode JetFilter::filterEvent() {
       FoundJet.setPy(jetpy);
       FoundJet.setPz(jetpz);
       FoundJet.setE(jete);
-      if (fabs(FoundJet.pseudoRapidity()) < m_UserEta) {
+      if (std::abs(FoundJet.pseudoRapidity()) < m_UserEta) {
         m_Jets.push_back(FoundJet);   //OK we found one. add it to the list  if its inside the eta region
       }
     }
diff --git a/Generators/GeneratorFilters/src/JetFilterWithTruthPhoton.cxx b/Generators/GeneratorFilters/src/JetFilterWithTruthPhoton.cxx
index 10ca6430a269386b74dd06ac4a1d3da75cc19033..e2a79e9bd4d82d6e8ef6516fcf70a34aa9cf8938 100644
--- a/Generators/GeneratorFilters/src/JetFilterWithTruthPhoton.cxx
+++ b/Generators/GeneratorFilters/src/JetFilterWithTruthPhoton.cxx
@@ -140,7 +140,7 @@ StatusCode JetFilterWithTruthPhoton::filterEvent() {
 	    &&(part->pdg_id() != 12 ) && (part->pdg_id() != -12 ) 
 	    &&(part->pdg_id() != 14 ) && (part->pdg_id() != -14 ) 
 	    &&(part->pdg_id() != 16 ) && (part->pdg_id() != -16 ) 
-	    && (fabs(part->momentum().pseudoRapidity()) <= m_emaxeta) 
+	    && (std::abs(part->momentum().pseudoRapidity()) <= m_emaxeta) 
 	     ){	// no neutrinos or muons and particles must be in active range
 	  int ip,ie;
 	  ip=(int) ((m_twopi/2.+ part->momentum().phi())/m_edphi); //phi is in range -pi to pi
@@ -158,7 +158,7 @@ StatusCode JetFilterWithTruthPhoton::filterEvent() {
 	  etgrid[ip][ie]=etgrid[ip][ie]+part->momentum().perp(); // fortran had pt here
 	  if (part->pdg_id() == 22 && 
 	      part->momentum().perp() > m_photonPt && 
-	      fabs(part->momentum().pseudoRapidity()) < m_photonEta) {
+	      std::abs(part->momentum().pseudoRapidity()) < m_photonEta) {
 	    MCTruthPhotonList.push_back(part);
 	  }
 #if 0
@@ -276,7 +276,7 @@ StatusCode JetFilterWithTruthPhoton::filterEvent() {
       FoundJet.setPy(jetpy);  
       FoundJet.setPz(jetpz);  
       FoundJet.setE(jete); 
-      if(fabs(FoundJet.pseudoRapidity())< m_UserEta && 
+      if(std::abs(FoundJet.pseudoRapidity())< m_UserEta && 
 	 FoundJet.vect().perp() > m_UserThresh){
 	int foundPhotons = 0;
 	//std::cout << "# of photons = " << MCTruthPhotonList.size() << std::endl;
@@ -284,8 +284,8 @@ StatusCode JetFilterWithTruthPhoton::filterEvent() {
 	if (m_photonSumPt >= 0. && MCTruthPhotonList.size() > 0) {
 	  double sumPt = 0.;
 	  for (unsigned int ig=0;ig<MCTruthPhotonList.size();++ig) {
-	    double deta = fabs(MCTruthPhotonList[ig]->momentum().pseudoRapidity()-FoundJet.pseudoRapidity());
-	    double dphi = fabs(MCTruthPhotonList[ig]->momentum().phi()-FoundJet.phi());
+	    double deta = std::abs(MCTruthPhotonList[ig]->momentum().pseudoRapidity()-FoundJet.pseudoRapidity());
+	    double dphi = std::abs(MCTruthPhotonList[ig]->momentum().phi()-FoundJet.phi());
 	    if (dphi > M_PI) dphi = 2.*M_PI - dphi;
 	    double dR = sqrt(deta*deta+dphi*dphi);
 	    if (dR < m_dRphotonjet) {
diff --git a/Generators/GeneratorFilters/src/LeadingPhotonFilter.cxx b/Generators/GeneratorFilters/src/LeadingPhotonFilter.cxx
index c9f83aa9fd26d2496046e2438ffeb477545d1196..f8a013c6a2fd6f75a1af85055f0a36d9f7fbf927 100644
--- a/Generators/GeneratorFilters/src/LeadingPhotonFilter.cxx
+++ b/Generators/GeneratorFilters/src/LeadingPhotonFilter.cxx
@@ -18,7 +18,7 @@ StatusCode LeadingPhotonFilter::filterEvent() {
   double ptmax = 0;
   for (auto p: *genEvt) {
     if (p->pdg_id() != 22 || p->status() != 1) continue;
-    if (fabs(p->momentum().pseudoRapidity()) > m_EtaRange) continue;
+    if (std::abs(p->momentum().pseudoRapidity()) > m_EtaRange) continue;
     ptmax = std::max(p->momentum().perp(), ptmax);
   }
   setFilterPassed(ptmax >= m_Ptmin && ptmax < m_Ptmax);
diff --git a/Generators/GeneratorFilters/src/LeptonFilter.cxx b/Generators/GeneratorFilters/src/LeptonFilter.cxx
index 561a35df411312e50842913b3c8345ee1ffa3559..e2762f641beebede5d468d20e30da9172617fdf1 100644
--- a/Generators/GeneratorFilters/src/LeptonFilter.cxx
+++ b/Generators/GeneratorFilters/src/LeptonFilter.cxx
@@ -50,7 +50,7 @@ StatusCode LeptonFilter::filterEvent() {
 		       << ": pT, eta = " << pT << ", " << eta );
         
         // If we've found a stable electron or muon, check eta and pt
-        if (pT > leading_lepton_pt && fabs(eta) <= m_EtaRange) {
+        if (pT > leading_lepton_pt && std::abs(eta) <= m_EtaRange) {
 	  leading_lepton_pt = pT;
         }
       }
diff --git a/Generators/GeneratorFilters/src/LeptonPairFilter.cxx b/Generators/GeneratorFilters/src/LeptonPairFilter.cxx
index 066e842e310d84eb7bd28d287a7a937a4ef579d8..e10105b1f66cbe3dc5763932b8e4961c8477312d 100644
--- a/Generators/GeneratorFilters/src/LeptonPairFilter.cxx
+++ b/Generators/GeneratorFilters/src/LeptonPairFilter.cxx
@@ -163,7 +163,7 @@ StatusCode LeptonPairFilter::filterEvent() {
 	      ((*pitr)->pdg_id() ==  13)  || 
 	      ((*pitr)->pdg_id() == -13) ){
 	      	//only consider leptons which satisfy  pt and eta requirements
-	        if( ((*pitr)->momentum().perp() >= m_Ptmin) && fabs((*pitr)->momentum().pseudoRapidity()) <=m_EtaRange){
+	        if( ((*pitr)->momentum().perp() >= m_Ptmin) && std::abs((*pitr)->momentum().pseudoRapidity()) <=m_EtaRange){
 			  if(m_onlyMassiveParents)
 			  {
 				  auto p = *pitr;
diff --git a/Generators/GeneratorFilters/src/MassRangeFilter.cxx b/Generators/GeneratorFilters/src/MassRangeFilter.cxx
index f4e383ec1861950247e6a45ff13000cba61c44cc..2f5e92caa28d8c867430e0677e2ce5207e9e9c16 100644
--- a/Generators/GeneratorFilters/src/MassRangeFilter.cxx
+++ b/Generators/GeneratorFilters/src/MassRangeFilter.cxx
@@ -46,7 +46,7 @@ StatusCode MassRangeFilter::filterEvent() {
       if ((*pitr1)->status() != m_PartStatus ) continue; //status of the particle
       if (std::abs((*pitr1)->pdg_id()) != std::abs(m_PartId) ) continue; //PDG ID selection
       if ((*pitr1)->momentum().perp() < m_Ptmin ) continue; // pT cut
-      if (fabs((*pitr1)->momentum().pseudoRapidity()) > m_EtaRange) continue; //eta cut
+      if (std::abs((*pitr1)->momentum().pseudoRapidity()) > m_EtaRange) continue; //eta cut
       auto pitr2 = genEvt_particles_begin;
       if (samePDGID) {
         pitr2 = pitr1;
@@ -57,7 +57,7 @@ StatusCode MassRangeFilter::filterEvent() {
         if ((*pitr2)->status() != m_PartStatus) continue;  //status of the particle
         if (std::abs((*pitr2)->pdg_id()) != std::abs(m_PartId2)) continue; //PDG ID selection
         if ((*pitr2)->momentum().perp() < m_Ptmin2) continue; // pT cut
-        if (fabs((*pitr2)->momentum().pseudoRapidity()) > m_EtaRange2) continue;//eta cut
+        if (std::abs((*pitr2)->momentum().pseudoRapidity()) > m_EtaRange2) continue;//eta cut
 
         HepMC::FourVector vec((*pitr1)->momentum().px() + (*pitr2)->momentum().px(),
                               (*pitr1)->momentum().py() + (*pitr2)->momentum().py(),
diff --git a/Generators/GeneratorFilters/src/MultiElectronFilter.cxx b/Generators/GeneratorFilters/src/MultiElectronFilter.cxx
index a733526843827528a954c975c9ea759484454336..5bcb3ff0b18e2c1ea72f2c76b4cd9f44f7d392f8 100644
--- a/Generators/GeneratorFilters/src/MultiElectronFilter.cxx
+++ b/Generators/GeneratorFilters/src/MultiElectronFilter.cxx
@@ -22,7 +22,7 @@ StatusCode MultiElectronFilter::filterEvent() {
     for (auto part: *genEvt) {
       if ( part->status() != 1) continue;
       if ( abs(part->pdg_id()) != 11) continue;
-	  if ( (part->momentum().perp() >= m_Ptmin) && fabs(part->momentum().pseudoRapidity()) <= m_EtaRange) {
+	  if ( (part->momentum().perp() >= m_Ptmin) && std::abs(part->momentum().pseudoRapidity()) <= m_EtaRange) {
 	    numElectrons++;
 	  }
 	}
diff --git a/Generators/GeneratorFilters/src/MultiLeptonFilter.cxx b/Generators/GeneratorFilters/src/MultiLeptonFilter.cxx
index 0e62fc746465bde42b52962ff95b83bdae8a10e2..ceace48f607a8e66dfc1394971713c0d66d18dc5 100644
--- a/Generators/GeneratorFilters/src/MultiLeptonFilter.cxx
+++ b/Generators/GeneratorFilters/src/MultiLeptonFilter.cxx
@@ -22,7 +22,7 @@ StatusCode MultiLeptonFilter::filterEvent() {
     for (auto part: *genEvt) {
       if ( part->status() != 1) continue;
 	  if ( abs(part->pdg_id()) == 11 || abs(part->pdg_id()) == 13 ) {
-	    if (part->momentum().perp() >= m_Ptmin && fabs(part->momentum().pseudoRapidity()) <= m_EtaRange) {
+	    if (part->momentum().perp() >= m_Ptmin && std::abs(part->momentum().pseudoRapidity()) <= m_EtaRange) {
 	      numLeptons += 1;
 	    }
 	  }
diff --git a/Generators/GeneratorFilters/src/MultiObjectsFilter.cxx b/Generators/GeneratorFilters/src/MultiObjectsFilter.cxx
index 9b2d1fb64c4b36dc98b88fa0186b2fa11ec5dde9..9588999fbc5536d801b9db4f2a8accae7b260705 100644
--- a/Generators/GeneratorFilters/src/MultiObjectsFilter.cxx
+++ b/Generators/GeneratorFilters/src/MultiObjectsFilter.cxx
@@ -62,7 +62,7 @@ StatusCode MultiObjectsFilter::filterEvent() {
   for (itr = events()->begin(); itr!=events()->end(); ++itr) {
     const HepMC::GenEvent* genEvt = (*itr);
     for (auto part: *genEvt) {
-      if (part->status()==1 && part->momentum().perp() > m_PtCut && fabs(part->momentum().pseudoRapidity()) < m_EtaCut) {
+      if (part->status()==1 && part->momentum().perp() > m_PtCut && std::abs(part->momentum().pseudoRapidity()) < m_EtaCut) {
         //electrons
         if (m_useEle && abs(part->pdg_id()) == 11) {
           ATH_MSG_DEBUG("Found electron: PT,ETA,PHI " << part->momentum().perp()/Gaudi::Units::GeV << "GeV, " << part->momentum().pseudoRapidity() << " " << part->momentum().phi());
@@ -86,7 +86,7 @@ StatusCode MultiObjectsFilter::filterEvent() {
     ATH_MSG_DEBUG("xAOD::JetContainer Size = " << truthjetTES->size());
 
     for (xAOD::JetContainer::const_iterator jitr = truthjetTES->begin(); jitr != truthjetTES->end(); ++jitr) {
-      if ((*jitr)->pt() > m_jetPtCut && fabs((*jitr)->eta()) < m_jetEtaCut) {
+      if ((*jitr)->pt() > m_jetPtCut && std::abs((*jitr)->eta()) < m_jetEtaCut) {
         ATH_MSG_DEBUG("Found jet: pT, eta, phi = " << (*jitr)->pt()/Gaudi::Units::GeV << "GeV, " << (*jitr)->eta() << " " << (*jitr)->phi());
         pt.push_back((*jitr)->pt());
       }
diff --git a/Generators/GeneratorFilters/src/PtmissAndOrLeptonFilter.cxx b/Generators/GeneratorFilters/src/PtmissAndOrLeptonFilter.cxx
index 3d65fe6c32215ac038d6616dbd860daf83f47a53..83a21e5872399d6a081fce6711430ed920471aa5 100644
--- a/Generators/GeneratorFilters/src/PtmissAndOrLeptonFilter.cxx
+++ b/Generators/GeneratorFilters/src/PtmissAndOrLeptonFilter.cxx
@@ -90,7 +90,7 @@ StatusCode PtmissAndOrLeptonFilter::filterEvent() {
     for (auto part: *genEvt){
       if (part->status() != 1) continue;
       const int abspid = abs(part->pdg_id());
-      const double abseta = fabs(part->momentum().pseudoRapidity());
+      const double abseta = std::abs(part->momentum().pseudoRapidity());
       if (abspid == 11 && part->momentum().perp() > m_PtminElectron && abseta <= m_MaxEtaElectron) nelec++;
       if (abspid == 13 && part->momentum().perp() > m_PtminMuon     && abseta <= m_MaxEtaMuon) nmuon++;
 
diff --git a/Generators/GeneratorFilters/src/QCDTruthJetFilter.cxx b/Generators/GeneratorFilters/src/QCDTruthJetFilter.cxx
index 2cd7130cb80fbde6aac660e048f64ef37ead5045..a44825b5b5c2a195becb4cf9e3ddc15fa93943d2 100644
--- a/Generators/GeneratorFilters/src/QCDTruthJetFilter.cxx
+++ b/Generators/GeneratorFilters/src/QCDTruthJetFilter.cxx
@@ -87,8 +87,6 @@ StatusCode QCDTruthJetFilter::filterEvent() {
   double pt_lead = -1;
   for (xAOD::JetContainer::const_iterator it_truth = (*truthjetTES).begin(); it_truth != (*truthjetTES).end() ; ++it_truth) {
     if (!(*it_truth)) continue;
-//    if (fabs( (*it_truth)->eta() ) > m_MaxEta) continue;
-//    if ((*it_truth)->eta()  > m_MaxEta || (*it_truth)->eta()  <= m_MinEta) continue;
     if ((*it_truth)->eta()>m_MaxEta || ( (*it_truth)->eta()<=m_MinEta && !m_SymEta) || ((*it_truth)->eta()<=m_MinEta && (*it_truth)->eta()>=-m_MinEta && m_SymEta)) continue;
     if (pt_lead < (*it_truth)->pt()) pt_lead = (*it_truth)->pt();
   }
diff --git a/Generators/GeneratorFilters/src/QCDTruthMultiJetFilter.cxx b/Generators/GeneratorFilters/src/QCDTruthMultiJetFilter.cxx
index 0ef767942286fd9de68de161c7f8839a2b45c7d2..7e6c059af85fcc204421f49ad93f60d5d6e4fed3 100644
--- a/Generators/GeneratorFilters/src/QCDTruthMultiJetFilter.cxx
+++ b/Generators/GeneratorFilters/src/QCDTruthMultiJetFilter.cxx
@@ -83,7 +83,7 @@ StatusCode QCDTruthMultiJetFilter::filterEvent() {
   double pt_lead = -1;
   for (xAOD::JetContainer::const_iterator it_truth = (*truthjetTES).begin(); it_truth != (*truthjetTES).end() ; ++it_truth) {
     if (!(*it_truth)) continue;
-    if (fabs( (*it_truth)->eta() ) > m_MaxEta) continue;
+    if (std::abs( (*it_truth)->eta() ) > m_MaxEta) continue;
     if ((*it_truth)->pt() > m_NjetMinPt*Gaudi::Units::GeV) Njet++;
     if (pt_lead < (*it_truth)->pt()) pt_lead = (*it_truth)->pt();
   }
diff --git a/Generators/GeneratorFilters/src/SoftLeptonFilter.cxx b/Generators/GeneratorFilters/src/SoftLeptonFilter.cxx
index afcca0b9690054a1b21f2eb3f1b0d9d28a891828..cab8b4df65e66a76eac92a1e634323707d334f58 100644
--- a/Generators/GeneratorFilters/src/SoftLeptonFilter.cxx
+++ b/Generators/GeneratorFilters/src/SoftLeptonFilter.cxx
@@ -18,7 +18,7 @@ StatusCode SoftLeptonFilter::filterEvent() {
     for (auto pitr: genEvt->particles()) {
       if (pitr->status() != 1) continue;
  	  if ( ( 2 != m_LeptonType && 11 == std::abs(pitr->pdg_id()) ) || ( 1 != m_LeptonType && 13 == std::abs(pitr->pdg_id())  )) {
-        if ((pitr->momentum().perp() >= m_Ptmin) && fabs(pitr->momentum().pseudoRapidity()) <= m_EtaRange) {
+        if ((pitr->momentum().perp() >= m_Ptmin) && std::abs(pitr->momentum().pseudoRapidity()) <= m_EtaRange) {
  		  // select e's from hadrons and from taus that come from hadrons,
  		  // and electrons from gammas that come from hadrons... (dalitz decay)
  		  auto decayVtx = pitr->production_vertex();
@@ -55,7 +55,7 @@ StatusCode SoftLeptonFilter::filterEvent() {
     for (HepMC::GenEvent::particle_const_iterator pitr = genEvt->particles_begin(); pitr != genEvt->particles_end(); ++pitr) {
       if ((*pitr)->status() != 1) continue;
  	  if ( ( 2 != m_LeptonType && 11 == abs((*pitr)->pdg_id()) ) || ( 1 != m_LeptonType && 13 == abs((*pitr)->pdg_id()) ) ) {
-        if ( ((*pitr)->momentum().perp() >= m_Ptmin) && fabs((*pitr)->momentum().pseudoRapidity()) <= m_EtaRange) {
+        if ( ((*pitr)->momentum().perp() >= m_Ptmin) && std::abs((*pitr)->momentum().pseudoRapidity()) <= m_EtaRange) {
  		  // select e's from hadrons and from taus that come from hadrons,
  		  // and electrons from gammas that come from hadrons... (dalitz decay)
  		  HepMC::GenVertex::particle_iterator firstParent;
diff --git a/Generators/GeneratorFilters/src/SoftLeptonInJetFilter.cxx b/Generators/GeneratorFilters/src/SoftLeptonInJetFilter.cxx
index 484f0ad4d47ca8460ae3b6d6f1f70f363bcdbdff..cc60593300de6dcb2cfd57f483263935e5ec9d67 100644
--- a/Generators/GeneratorFilters/src/SoftLeptonInJetFilter.cxx
+++ b/Generators/GeneratorFilters/src/SoftLeptonInJetFilter.cxx
@@ -84,8 +84,8 @@ StatusCode SoftLeptonInJetFilter::filterEvent() {
 
       for (int ie=0; ie < NLeptons; ie++ ) {
         double deltaEta = eta_b[ib]-eta_e[ie];
-        double deltaPhi = fabs(phi_b[ib]-phi_e[ie]);
-        if (deltaPhi  > M_PI ) deltaPhi = fabs(deltaPhi-2*M_PI);
+        double deltaPhi = std::abs(phi_b[ib]-phi_e[ie]);
+        if (deltaPhi  > M_PI ) deltaPhi = std::abs(deltaPhi-2*M_PI);
         dR = sqrt(deltaEta*deltaEta + deltaPhi*deltaPhi);
 
         if (dR < m_jet_cone) {
diff --git a/Generators/GeneratorFilters/src/TTbarPlusHeavyFlavorFilter.cxx b/Generators/GeneratorFilters/src/TTbarPlusHeavyFlavorFilter.cxx
index 681ab365ae0d418373a5504db8cd6e19cf955b0f..5092d2403ce78c454e302ca62946097e09d472a6 100644
--- a/Generators/GeneratorFilters/src/TTbarPlusHeavyFlavorFilter.cxx
+++ b/Generators/GeneratorFilters/src/TTbarPlusHeavyFlavorFilter.cxx
@@ -160,7 +160,7 @@ bool TTbarPlusHeavyFlavorFilter::passBSelection(HepMC::ConstGenParticlePtr part)
 
   const HepMC::FourVector& p4 = part->momentum();
   double pt = p4.perp();
-  double eta = fabs(p4.eta());
+  double eta = std::abs(p4.eta());
 
   if(pt<m_bPtMinCut) return false;
   if(eta>m_bEtaMaxCut) return false;
@@ -173,7 +173,7 @@ bool TTbarPlusHeavyFlavorFilter::passCSelection(HepMC::ConstGenParticlePtr part)
 
   const HepMC::FourVector& p4 = part->momentum();
   double pt = p4.perp();
-  double eta = fabs(p4.eta());
+  double eta = std::abs(p4.eta());
 
   if(pt<m_cPtMinCut) return false;
   if(eta>m_cEtaMaxCut) return false;
diff --git a/Generators/GeneratorFilters/src/TTbarPlusJetsFilter.cxx b/Generators/GeneratorFilters/src/TTbarPlusJetsFilter.cxx
index 017a6f3172ce1d72a3f2a6815ed2001241520ed1..4da199387439459dcdb1011583255bc603272e1f 100644
--- a/Generators/GeneratorFilters/src/TTbarPlusJetsFilter.cxx
+++ b/Generators/GeneratorFilters/src/TTbarPlusJetsFilter.cxx
@@ -122,14 +122,14 @@ StatusCode TTbarPlusJetsFilter::filterEvent() {
     const TLorentzVector jet_tlv = (*jiter)->p4();
     const CLHEP::HepLorentzVector jet_hlv(jet_tlv.Px(), jet_tlv.Py(), jet_tlv.Pz(), jet_tlv.E());
 
-    if (jet_tlv.Et() >= m_ptMinJet && fabs(aJet->eta())<= m_etaMaxJet) {
+    if (jet_tlv.Et() >= m_ptMinJet && std::abs(aJet->eta())<= m_etaMaxJet) {
       ijet++;
       ATH_MSG_VERBOSE("-> jet : eta = " << aJet->eta() << " phi = " << aJet->phi() << " pt = "  << jet_tlv.Et());
-      if (aJet->pt() >= m_ptMinJetB && fabs(aJet->eta()) <= m_etaMaxJetB) {
+      if (aJet->pt() >= m_ptMinJetB && std::abs(aJet->eta()) <= m_etaMaxJetB) {
         bool isjet = true;
         for (unsigned int iele = 0; iele < electronFakingJetCandidates.size(); iele++) {
           double deltaR  = jet_hlv.deltaR( electronFakingJetCandidates[iele] );
-          double deltaPt = fabs(jet_tlv.Et() - electronFakingJetCandidates[iele].perp());
+          double deltaPt = std::abs(jet_tlv.Et() - electronFakingJetCandidates[iele].perp());
           ATH_MSG_VERBOSE("--> matching to electron " << iele << " dR = " << deltaR << " dPt = " << deltaPt << " dPt/Pt = " << deltaPt/jet_tlv.Et());
           if (deltaR < 0.4 && deltaPt/jet_tlv.Et() < 0.1) isjet = false;
         }
diff --git a/Generators/GeneratorFilters/src/TauFilter.cxx b/Generators/GeneratorFilters/src/TauFilter.cxx
index 774c86810171886dc4d2edc255435cbb273287f7..66a77781272b8f5cbc453b9a47d28f612cd9f710 100644
--- a/Generators/GeneratorFilters/src/TauFilter.cxx
+++ b/Generators/GeneratorFilters/src/TauFilter.cxx
@@ -108,19 +108,19 @@ StatusCode TauFilter::filterEvent() {
         if ( leptonic == 1 ) {
           m_eventse++;
           if ( tauvis.perp() < m_pTmine ) continue;
-          if ( fabs( tauvis.eta() ) > m_etaMaxe ) continue;
+          if ( std::abs( tauvis.eta() ) > m_etaMaxe ) continue;
           ntau++;
           m_eventseacc++;
         } else if ( leptonic == 2 ) {
           m_eventsmu++;
           if ( tauvis.perp() < m_pTminmu ) continue;
-          if ( fabs( tauvis.eta() ) > m_etaMaxmu ) continue;
+          if ( std::abs( tauvis.eta() ) > m_etaMaxmu ) continue;
           ntau++;
           m_eventsmuacc++;
         } else if ( leptonic == 0 ) {
           m_eventshad++;
           if ( tauvis.perp() < m_pTminhad ) continue;
-          if ( fabs( tauvis.eta() ) > m_etaMaxhad ) continue;
+          if ( std::abs( tauvis.eta() ) > m_etaMaxhad ) continue;
           ntau++;
           m_eventshadacc++;
         }
diff --git a/Generators/GeneratorFilters/src/TopCKMFilter.cxx b/Generators/GeneratorFilters/src/TopCKMFilter.cxx
index 0c8eba4416a5d7b88d75349f9740684b757e8186..8b749b18453a2e306cd80cfdb94d4259c27eb384 100644
--- a/Generators/GeneratorFilters/src/TopCKMFilter.cxx
+++ b/Generators/GeneratorFilters/src/TopCKMFilter.cxx
@@ -71,9 +71,9 @@ StatusCode TopCKMFilter::filterEvent() {
         HepMC::GenParticle * wBoson2 = 0;
 
         for (firstChildItr = firstChild1; firstChildItr != firstChildE; ++firstChildItr) {
-          if ((abs((*firstChildItr)->pdg_id()) == m_PDGChild[0] || abs((*firstChildItr)->pdg_id()) == m_PDGChild[1])
+          if ((std::abs((*firstChildItr)->pdg_id()) == m_PDGChild[0] || std::abs((*firstChildItr)->pdg_id()) == m_PDGChild[1])
               && (*firstChildItr)->momentum().perp() > m_PtMinChild
-              && fabs((*firstChildItr)->momentum().eta()) < m_EtaRangeChild) {
+              && std::abs((*firstChildItr)->momentum().eta()) < m_EtaRangeChild) {
             isOK1 = 1;
             quark1 = (*firstChildItr);
           }
@@ -83,7 +83,7 @@ StatusCode TopCKMFilter::filterEvent() {
         for (secondChildItr = secondChild1; secondChildItr != secondChildE; ++secondChildItr) {
           if ((abs((*secondChildItr)->pdg_id()) == m_PDGChild[0] || abs((*secondChildItr)->pdg_id()) == m_PDGChild[1])
               && (*secondChildItr)->momentum().perp() > m_PtMinChild
-              && fabs((*secondChildItr)->momentum().eta()) < m_EtaRangeChild){
+              && std::abs((*secondChildItr)->momentum().eta()) < m_EtaRangeChild){
             isOK2 = 1;
             quark2 = (*secondChildItr);
           }
diff --git a/Generators/GeneratorFilters/src/TopCKMKinFilter.cxx b/Generators/GeneratorFilters/src/TopCKMKinFilter.cxx
index 13dc2976d4bb423f9c9a494ef041950b0a2c2009..f91f010f2755d939b685a615e4975779dc9c629b 100644
--- a/Generators/GeneratorFilters/src/TopCKMKinFilter.cxx
+++ b/Generators/GeneratorFilters/src/TopCKMKinFilter.cxx
@@ -79,7 +79,7 @@ StatusCode TopCKMKinFilter::filterEvent() {
         for (firstChildItr = firstChild1; firstChildItr != firstChildE; ++firstChildItr){
           if ((std::abs((*firstChildItr)->pdg_id()) == m_PDGChild[0] || std::abs((*firstChildItr)->pdg_id()) == m_PDGChild[1])
               && (*firstChildItr)->momentum().perp() > m_PtMinChild
-              && fabs((*firstChildItr)->momentum().eta()) < m_EtaRangeChild){
+              && std::abs((*firstChildItr)->momentum().eta()) < m_EtaRangeChild){
             isOK1 = 1;
             quark1 = (*firstChildItr);
           }
@@ -89,7 +89,7 @@ StatusCode TopCKMKinFilter::filterEvent() {
         for (secondChildItr = secondChild1; secondChildItr != secondChildE; ++secondChildItr){
           if ((std::abs((*secondChildItr)->pdg_id()) == m_PDGChild[0] || std::abs((*secondChildItr)->pdg_id()) == m_PDGChild[1])
               && (*secondChildItr)->momentum().perp() > m_PtMinChild
-              && fabs((*secondChildItr)->momentum().eta()) < m_EtaRangeChild){
+              && std::abs((*secondChildItr)->momentum().eta()) < m_EtaRangeChild){
             isOK2 = 1;
             quark2 = (*secondChildItr);
           }
@@ -116,14 +116,14 @@ StatusCode TopCKMKinFilter::filterEvent() {
         for (w1SonItr = w1Son1; w1SonItr != w1SonE; ++w1SonItr){
           if (std::abs((*w1SonItr)->pdg_id()) == 15) isTau1 = 1;
           if (std::abs((*w1SonItr)->pdg_id()) == 11 || std::abs((*w1SonItr)->pdg_id()) == 13){
-            if ((*w1SonItr)->momentum().perp() > m_PtMinChild && fabs((*w1SonItr)->momentum().eta()) < m_EtaRangeChild) isKinLep1 = 1;
+            if ((*w1SonItr)->momentum().perp() > m_PtMinChild && std::abs((*w1SonItr)->momentum().eta()) < m_EtaRangeChild) isKinLep1 = 1;
           }
         }
 
         for (w2SonItr = w2Son1; w2SonItr != w2SonE; ++w2SonItr){
           if (std::abs((*w2SonItr)->pdg_id()) == 15) isTau2 = 1;
           if (std::abs((*w2SonItr)->pdg_id()) == 11 || std::abs((*w2SonItr)->pdg_id()) == 13){
-            if ((*w2SonItr)->momentum().perp() > m_PtMinChild && fabs((*w2SonItr)->momentum().eta()) < m_EtaRangeChild) isKinLep2 = 1;
+            if ((*w2SonItr)->momentum().perp() > m_PtMinChild && std::abs((*w2SonItr)->momentum().eta()) < m_EtaRangeChild) isKinLep2 = 1;
           }
         }
 
diff --git a/Generators/GeneratorFilters/src/TrimuMassRangeFilter.cxx b/Generators/GeneratorFilters/src/TrimuMassRangeFilter.cxx
index 4a04215961cca72cdcb5216af05620bfe847773a..081e1cfd16540a1c3b8358ba813a5011e56591c2 100644
--- a/Generators/GeneratorFilters/src/TrimuMassRangeFilter.cxx
+++ b/Generators/GeneratorFilters/src/TrimuMassRangeFilter.cxx
@@ -107,7 +107,7 @@ StatusCode TrimuMassRangeFilter::filterEvent() {
       if( ( std::abs((*pitr1)->pdg_id()) != std::abs(m_PartId1)  && 99999 != std::abs(m_PartId1) ) || //PDG ID selection
           (*pitr1)->status() != m_PartStatus  ||    //status of the particle 
           (*pitr1)->momentum().perp() < m_Ptmin1  || // pT cut
-          fabs((*pitr1)->momentum().pseudoRapidity()) > m_EtaRange1
+          std::abs((*pitr1)->momentum().pseudoRapidity()) > m_EtaRange1
         ) continue;//eta cut
           
       ATH_MSG_INFO( "   type1 " << (*pitr1)->pdg_id() << " pT1 " << (*pitr1)->momentum().perp()
@@ -127,7 +127,7 @@ StatusCode TrimuMassRangeFilter::filterEvent() {
         if( ( std::abs((*pitr2)->pdg_id()) != std::abs(m_PartId2) && 99999 != std::abs(m_PartId2) ) || //PDG ID selection
             (*pitr2)->status() != m_PartStatus  ||    //status of the particle 
             (*pitr2)->momentum().perp() < m_Ptmin2  || // pT cut
-            fabs((*pitr2)->momentum().pseudoRapidity()) > m_EtaRange2
+            std::abs((*pitr2)->momentum().pseudoRapidity()) > m_EtaRange2
           ) continue;//eta cut
         if( samePDGID12 && !samePDGID123 && (*pitr1)->pdg_id()==(*pitr2)->pdg_id()) continue;
           
@@ -148,7 +148,7 @@ StatusCode TrimuMassRangeFilter::filterEvent() {
           if( ( std::abs((*pitr3)->pdg_id()) != std::abs(m_PartId3) && 99999 != std::abs(m_PartId3) ) || //PDG ID selection
               (*pitr3)->status() != m_PartStatus  ||    //status of the particle 
               (*pitr3)->momentum().perp() < m_Ptmin3  || // pT cut
-              fabs((*pitr3)->momentum().pseudoRapidity()) > m_EtaRange3
+              std::abs((*pitr3)->momentum().pseudoRapidity()) > m_EtaRange3
             ) continue;//eta cut
           
           ATH_MSG_INFO( "   type3 " << (*pitr3)->pdg_id() << " pT3 " << (*pitr3)->momentum().perp()
diff --git a/Generators/GeneratorFilters/src/TruthJetFilter.cxx b/Generators/GeneratorFilters/src/TruthJetFilter.cxx
index afad534b6ee22a9f8b365a17c718d9b62e009fd0..ba54ce084553f1d6601605a521fa6b5701fa5870 100644
--- a/Generators/GeneratorFilters/src/TruthJetFilter.cxx
+++ b/Generators/GeneratorFilters/src/TruthJetFilter.cxx
@@ -45,12 +45,12 @@ StatusCode TruthJetFilter::filterEvent() {
   std::vector<const xAOD::Jet*> listOfSelectedJets;
   const xAOD::Jet* leadingJet = 0;
   for (xAOD::JetContainer::const_iterator it_truth = (*truthjetTES).begin(); it_truth != (*truthjetTES).end() ; ++it_truth) {
-    if ( (*it_truth)->pt() > m_NjetMinPt && fabs( (*it_truth)->eta() ) < m_NjetMaxEta ) {
+    if ( (*it_truth)->pt() > m_NjetMinPt && std::abs( (*it_truth)->eta() ) < m_NjetMaxEta ) {
       Njet++;
       ATH_MSG_INFO("Jet pt " << (*it_truth)->pt()/Gaudi::Units::GeV);
       if (m_applyDeltaPhiCut) listOfSelectedJets.push_back(*it_truth);
     }
-    if ( (*it_truth)->pt() > m_jet_pt1 && fabs( (*it_truth)->eta() ) < m_NjetMaxEta ) {
+    if ( (*it_truth)->pt() > m_jet_pt1 && std::abs( (*it_truth)->eta() ) < m_NjetMaxEta ) {
       Njet_pt1++;
       ATH_MSG_INFO("High jet pt " << (*it_truth)->pt()/Gaudi::Units::GeV);
       if (m_applyDeltaPhiCut && (!leadingJet || (*it_truth)->pt() > leadingJet->pt())) {
@@ -66,7 +66,7 @@ StatusCode TruthJetFilter::filterEvent() {
       for (unsigned int iJet = 0; iJet < m_Njet; iJet++) {
         if (listOfSelectedJets[iJet] == leadingJet) continue;
         double deltaPhi = leadingJet->p4().DeltaPhi((listOfSelectedJets[iJet])->p4());
-        double dPi = TMath::Pi() - fabs(deltaPhi);
+        double dPi = TMath::Pi() - std::abs(deltaPhi);
         ATH_MSG_DEBUG("deltaPhi = " << deltaPhi << ", dPi = " << dPi <<
                       " between leading jet(pt=" << leadingJet->pt() << ",eta=" << leadingJet->eta() <<
                       ") and jet(pt=" << (listOfSelectedJets[iJet])->pt() <<
diff --git a/Generators/GeneratorFilters/src/VBFForwardJetsFilter.cxx b/Generators/GeneratorFilters/src/VBFForwardJetsFilter.cxx
index 786b3a2385c9696378e35899ed20ab1286bea647..0c4f88eeeee4b9f0620b4104e8522437a7dd1343 100644
--- a/Generators/GeneratorFilters/src/VBFForwardJetsFilter.cxx
+++ b/Generators/GeneratorFilters/src/VBFForwardJetsFilter.cxx
@@ -140,13 +140,13 @@ StatusCode VBFForwardJetsFilter::filterEvent() {
     for (HepMC::GenEvent::particle_const_iterator pitr = genEvt->particles_begin(); pitr != genEvt->particles_end(); ++pitr) {
       // photon
       if ( (*pitr)->pdg_id() == 22 && (*pitr)->status() == 1 &&
-           (*pitr)->momentum().perp() >= m_LGMinPt && fabs((*pitr)->momentum().pseudoRapidity()) <= m_LGMaxEta) {
+           (*pitr)->momentum().perp() >= m_LGMinPt && std::abs((*pitr)->momentum().pseudoRapidity()) <= m_LGMaxEta) {
         MCTruthPhotonList.push_back((*pitr));
         ATH_MSG_INFO("photon pt(Gaudi::Units::GeV) = " << (*pitr)->momentum().perp()/Gaudi::Units::GeV << " eta = " << (*pitr)->momentum().pseudoRapidity());
       }
       // electon
       if ( abs((*pitr)->pdg_id()) == 11 && (*pitr)->status() == 1 &&
-           (*pitr)->momentum().perp() >= m_LGMinPt && fabs((*pitr)->momentum().pseudoRapidity()) <= m_LGMaxEta) {
+           (*pitr)->momentum().perp() >= m_LGMinPt && std::abs((*pitr)->momentum().pseudoRapidity()) <= m_LGMaxEta) {
         MCTruthElectronList.push_back((*pitr));
         ATH_MSG_INFO("electron pt(Gaudi::Units::GeV) = " << (*pitr)->momentum().perp()/Gaudi::Units::GeV << " eta = " << (*pitr)->momentum().pseudoRapidity());
       }
@@ -182,7 +182,7 @@ StatusCode VBFForwardJetsFilter::filterEvent() {
   // Select TruthJets
   std::vector<const xAOD::Jet*> jetList;
   for (xAOD::JetContainer::const_iterator it_truth = truthjetTES->begin(); it_truth != truthjetTES->end(); ++it_truth) {
-    if ( (*it_truth)->pt() > m_JetMinPt && fabs( (*it_truth)->eta() ) < m_JetMaxEta ) {
+    if ( (*it_truth)->pt() > m_JetMinPt && std::abs( (*it_truth)->eta() ) < m_JetMaxEta ) {
       jetList.push_back(*it_truth);
       ATH_MSG_INFO("jet pt(Gaudi::Units::GeV) = " << (*it_truth)->pt()/Gaudi::Units::GeV << " eta = " << (*it_truth)->eta());
     }
@@ -203,7 +203,7 @@ StatusCode VBFForwardJetsFilter::filterEvent() {
     flag1stJet = 0;
     if (jetList.size() >= 1) {
       const xAOD::Jet *j1 = jetList[0];
-      if (j1->pt() > m_Jet1MinPt && fabs(j1->eta()) < m_Jet1MaxEta) {
+      if (j1->pt() > m_Jet1MinPt && std::abs(j1->eta()) < m_Jet1MaxEta) {
         flag1stJet = 1;
       }
     }
@@ -215,7 +215,7 @@ StatusCode VBFForwardJetsFilter::filterEvent() {
     flag2ndJet = 0;
     if (jetList.size() >= 2) {
       const xAOD::Jet *j2 = jetList[1];
-      if (j2->pt() > m_Jet2MinPt && fabs(j2->eta()) < m_Jet2MaxEta) {
+      if (j2->pt() > m_Jet2MinPt && std::abs(j2->eta()) < m_Jet2MaxEta) {
         flag2ndJet = 1;
       }
     }
@@ -241,7 +241,7 @@ StatusCode VBFForwardJetsFilter::filterEvent() {
       int okMassJJ = m_MassJJ >= 0. ? 0 : 1;
       for (unsigned i=0;i<jetList.size()-1;++i) {
         for (unsigned j=i+1;j<jetList.size();++j) {
-          double dEta = fabs(jetList[i]->eta()-jetList[j]->eta());
+          double dEta = std::abs(jetList[i]->eta()-jetList[j]->eta());
           double Mjj = (jetList[i]->p4()+jetList[j]->p4()).M();
           ATH_MSG_INFO("DeltaEtaJJ = " << dEta << " MassJJ(CLHEP::GeV) = " << Mjj/CLHEP::GeV << " (" << i << ", " << j << ")");
           if (okDeltaEtaJJ == 0 && dEta > m_DeltaEtaJJ) okDeltaEtaJJ = 1;
@@ -296,7 +296,7 @@ double VBFForwardJetsFilter::getMinDeltaR(const xAOD::Jet *jet, std::vector<HepM
       if (dphi >  M_PI) { dphi -= 2.*M_PI; }
       if (dphi < -M_PI) { dphi += 2.*M_PI; }
       double dr = sqrt(deta*deta+dphi*dphi);
-      double ratio_pt= fabs((jet->pt()-list[i]->momentum().perp())/list[i]->momentum().perp());
+      double ratio_pt= std::abs((jet->pt()-list[i]->momentum().perp())/list[i]->momentum().perp());
       if (ratio_pt < m_RatioPtJLG && dr < minDR) minDR = dr;
     }
   }
@@ -313,7 +313,7 @@ double VBFForwardJetsFilter::getMinDeltaR(const xAOD::Jet *jet, std::vector<CLHE
       if (dphi >  M_PI) { dphi -= 2.*M_PI; }
       if (dphi < -M_PI) { dphi += 2.*M_PI; }
       double dr = std::sqrt(deta*deta+dphi*dphi);
-      double ratio_pt= fabs((jet->pt()-list[i].vect().perp())/list[i].vect().perp());
+      double ratio_pt= std::abs((jet->pt()-list[i].vect().perp())/list[i].vect().perp());
       if (ratio_pt < m_RatioPtJLG && dr < minDR) minDR = dr;
     }
   }
diff --git a/Generators/GeneratorFilters/src/VBFMjjIntervalFilter.cxx b/Generators/GeneratorFilters/src/VBFMjjIntervalFilter.cxx
index 77c431e8ac42c88015a3e14944944bc9da5ffa0f..0d1ccfb52ff066b61e7a2591b1ebdb72efd67ae5 100644
--- a/Generators/GeneratorFilters/src/VBFMjjIntervalFilter.cxx
+++ b/Generators/GeneratorFilters/src/VBFMjjIntervalFilter.cxx
@@ -90,7 +90,7 @@ StatusCode VBFMjjIntervalFilter::filterEvent() {
 	// photon - copied from VBFForwardJetsFilter.cxx
 	if ( (*pitr)->pdg_id() == 22 && (*pitr)->status() == 1 &&
 	     (*pitr)->momentum().perp() >= m_olapPt && 
-	     fabs((*pitr)->momentum().pseudoRapidity()) <= m_yMax) {
+	     std::abs((*pitr)->momentum().pseudoRapidity()) <= m_yMax) {
 	  MCTruthPhotonList.push_back((*pitr));
 	}
       }
@@ -98,7 +98,7 @@ StatusCode VBFMjjIntervalFilter::filterEvent() {
 	// electron
 	if (abs((*pitr)->pdg_id()) == 11 && (*pitr)->status() == 1 &&
 	    (*pitr)->momentum().perp() >= m_olapPt &&
-	    fabs((*pitr)->momentum().pseudoRapidity()) <= m_yMax) {
+	    std::abs((*pitr)->momentum().pseudoRapidity()) <= m_yMax) {
 	  MCTruthElectronList.push_back((*pitr));
 	}
       }
@@ -122,7 +122,7 @@ StatusCode VBFMjjIntervalFilter::filterEvent() {
 									  tau->momentum().py()-nutau.py(),
 									  tau->momentum().pz()-nutau.pz(),
 									  tau->momentum().e()-nutau.e());
-	    if (tauvis->vect().perp() >= m_olapPt && fabs(tauvis->vect().pseudoRapidity()) <= m_yMax) {
+	    if (tauvis->vect().perp() >= m_olapPt && std::abs(tauvis->vect().pseudoRapidity()) <= m_yMax) {
 	      MCTruthTauList.push_back(tauvis);
 	    } else {
 	      delete tauvis;
@@ -136,7 +136,7 @@ StatusCode VBFMjjIntervalFilter::filterEvent() {
   // Filter based on rapidity acceptance and sort
   xAOD::JetContainer filteredJets(SG::VIEW_ELEMENTS);
   for (xAOD::JetContainer::const_iterator jitr = truthJetCollection->begin(); jitr != truthJetCollection->end(); ++jitr) {
-    if (fabs( (*jitr)->rapidity() ) < m_yMax && (*jitr)->pt() >= m_olapPt) {
+    if (std::abs( (*jitr)->rapidity() ) < m_yMax && (*jitr)->pt() >= m_olapPt) {
       bool JetOverlapsWithPhoton   = false;
       bool JetOverlapsWithElectron = false;
       bool JetOverlapsWithTau      = false;
diff --git a/Generators/GeneratorFilters/src/WZtoLeptonFilter.cxx b/Generators/GeneratorFilters/src/WZtoLeptonFilter.cxx
index 0b705e77c3723c6b112f3201eff12b66eab385ae..c91f1f2002fd2175abe2caf3974cbf41a1df31e4 100644
--- a/Generators/GeneratorFilters/src/WZtoLeptonFilter.cxx
+++ b/Generators/GeneratorFilters/src/WZtoLeptonFilter.cxx
@@ -252,7 +252,7 @@ StatusCode WZtoLeptonFilter::filterEvent() {
 
       if ((abslepid == 11 || abslepid == 13) && (*pitr)->status() == 1) {
         double leppt = (*pitr)->momentum().perp();
-        double lepeta = fabs( (*pitr)->momentum().pseudoRapidity() );
+        double lepeta = std::abs( (*pitr)->momentum().pseudoRapidity() );
 
         LePrdVrt = (*pitr)->production_vertex();
         int anceWZ = 0;
diff --git a/Generators/GeneratorUtils/test/StringParse_test.cxx b/Generators/GeneratorUtils/test/StringParse_test.cxx
index d31a8d589c6f7c4ba216dbbca85c737522555333..2ecd38919754f40dded64e61798b0f4d81f378ae 100644
--- a/Generators/GeneratorUtils/test/StringParse_test.cxx
+++ b/Generators/GeneratorUtils/test/StringParse_test.cxx
@@ -34,12 +34,12 @@ int main() {
   assert(s.piece<string>(2) == "foo");
 
   assert(s.piece(3) == "5.678");
-  assert(fabs(s.piece<double>(3) - 5.678) < 1e-6);
-  assert(fabs(s.numpiece(3) - 5.678) < 1e-6);
+  assert(std::abs(s.piece<double>(3) - 5.678) < 1e-6);
+  assert(std::abs(s.numpiece(3) - 5.678) < 1e-6);
 
   assert(s.piece<int>(4) != 1234);
   assert(s.intpiece(4) == -1);
 
-  assert(fabs(s.piece<double>(5) + 1) < 1e-6);
-  assert(fabs(s.numpiece(5) + 1) < 1e-6);
+  assert(std::abs(s.piece<double>(5) + 1) < 1e-6);
+  assert(std::abs(s.numpiece(5) + 1) < 1e-6);
 }
diff --git a/Generators/Hijing_i/src/Hijing.cxx b/Generators/Hijing_i/src/Hijing.cxx
index 346f0e2097af1a79245e921a4a6f3bfb6cc14cea..c81769b3136f6804bbd2072d92720e7e2e43bd42 100644
--- a/Generators/Hijing_i/src/Hijing.cxx
+++ b/Generators/Hijing_i/src/Hijing.cxx
@@ -815,16 +815,16 @@ Hijing::randomizeVertex()
   double ranx, rany, xmax, ymax;
   double ranz = CLHEP::RandFlat::shoot(engine, -Zmax, Zmax);
   if( m_wide ){ // Allow the whole pipe
-    if( fabs(ranz) < Start1 ) {
+    if( std::abs(ranz) < Start1 ) {
       xmax = Xmin + Delta1;
       ymax = xmax;
-    } else if( fabs(ranz) < Start2 ) {
+    } else if( std::abs(ranz) < Start2 ) {
       xmax = Xmin + Delta2;
       ymax = xmax;
-    } else if( fabs(ranz) < Start3 ) {
+    } else if( std::abs(ranz) < Start3 ) {
       xmax = Xmin + Delta3;
       ymax = xmax;
-    } else if ( fabs(ranz) <= Envelope ){
+    } else if ( std::abs(ranz) <= Envelope ){
       xmax = Xmin;
       ymax = xmax;
     } else {    
diff --git a/Generators/MCTester_i/src/MCTesterAlg.cxx b/Generators/MCTester_i/src/MCTesterAlg.cxx
index 9186b82f305a31e4c6c20be29fb7d967964f2bf9..6da18ea11be51284cf3de913e61831a282bcbaae 100644
--- a/Generators/MCTester_i/src/MCTesterAlg.cxx
+++ b/Generators/MCTester_i/src/MCTesterAlg.cxx
@@ -231,10 +231,10 @@ StatusCode MCTesterAlg::MC_Validate_check4MomentumSum(HepMCEvent * e)
 {
   std::vector<double> * sum = e->Sum4Momentum();
 
-  if(fabs(sum->at(0)-m_collision_px)>m_collision_check_sum_margin || 
-     fabs(sum->at(1)-m_collision_py)>m_collision_check_sum_margin ||
-     fabs(sum->at(2)-m_collision_pz)>m_collision_check_sum_margin ||
-     fabs(sum->at(3)-m_collision_E)>m_collision_check_sum_margin) {
+  if(std::abs(sum->at(0)-m_collision_px)>m_collision_check_sum_margin || 
+     std::abs(sum->at(1)-m_collision_py)>m_collision_check_sum_margin ||
+     std::abs(sum->at(2)-m_collision_pz)>m_collision_check_sum_margin ||
+     std::abs(sum->at(3)-m_collision_E)>m_collision_check_sum_margin) {
 
     m_deviation_from_centre_of_mass++;
     ATH_MSG_WARNING("Event " << e->GetEventNumber() << 
diff --git a/Generators/ParticleDecayer/src/ParticleDecayer.cxx b/Generators/ParticleDecayer/src/ParticleDecayer.cxx
index 1ee6fd0b6c6b9bc2c7299d69e59da7e2becccaf4..cc1eab0707e67c19198c36a1ba6867a88c4d0409 100644
--- a/Generators/ParticleDecayer/src/ParticleDecayer.cxx
+++ b/Generators/ParticleDecayer/src/ParticleDecayer.cxx
@@ -157,7 +157,7 @@ StatusCode ParticleDecayer::setDecayPosition( HepMC::GenParticlePtr genpart, Hep
                double distanceToEdge = -999.;
                if ( theta < m_thetaEndCapBarrel || theta > ( CLHEP::pi - m_thetaEndCapBarrel) ) // Particle escapes through endcap
                   {
-                     distanceToEdge = fabs(m_endCapDistance/cos(theta));
+                     distanceToEdge = std::abs(m_endCapDistance/cos(theta));
                   }
                else // Particle escapes through barrel
                   {
@@ -189,12 +189,12 @@ StatusCode ParticleDecayer::setDecayPosition( HepMC::GenParticlePtr genpart, Hep
          double decayRadius = -999.;
          if ( theta < m_thetaEndCapBarrel || theta > ( CLHEP::pi - m_thetaEndCapBarrel) ) // Particle escapes through endcap
             {
-               double outerLength = fabs(m_endCapDistance/cos(theta));
+               double outerLength = std::abs(m_endCapDistance/cos(theta));
                double outerRadius = outerLength*sin(theta);
-               decayRadius        = rnd_DoubleRange(0., std::min(outerRadius, fabs(m_barrelRadius)) );
+               decayRadius        = rnd_DoubleRange(0., std::min(outerRadius, std::abs(m_barrelRadius)) );
             }else // Particle escapes through barrel
             {
-               decayRadius = rnd_DoubleRange(0., fabs(m_barrelRadius));
+               decayRadius = rnd_DoubleRange(0., std::abs(m_barrelRadius));
             }
 
          double decayLength = decayRadius/sin(theta);
diff --git a/Generators/Prophecy4fControl/bin/DRM.C b/Generators/Prophecy4fControl/bin/DRM.C
index 655c361d365df7784383ca2fa62e18f556b6c9cb..aa92e060de6e805e2567820fa67b599379dcffa9 100644
--- a/Generators/Prophecy4fControl/bin/DRM.C
+++ b/Generators/Prophecy4fControl/bin/DRM.C
@@ -199,8 +199,8 @@ void DRM::Merge(){
 	}
 	
 	double mass1, mass2;
-	P4_Z[4][0] = sqrt(P4_Z[3][0] * P4_Z[3][0] - P4_Z[0][0] * P4_Z[0][0] - P4_Z[1][0] * P4_Z[1][0] - P4_Z[2][0] * P4_Z[2][0]);
-	P4_Z[4][1] = sqrt(P4_Z[3][1] * P4_Z[3][1] - P4_Z[0][1] * P4_Z[0][1] - P4_Z[1][1] * P4_Z[1][1] - P4_Z[2][1] * P4_Z[2][1]);
+	P4_Z[4][0] = std::sqrt(P4_Z[3][0] * P4_Z[3][0] - P4_Z[0][0] * P4_Z[0][0] - P4_Z[1][0] * P4_Z[1][0] - P4_Z[2][0] * P4_Z[2][0]);
+	P4_Z[4][1] = std::sqrt(P4_Z[3][1] * P4_Z[3][1] - P4_Z[0][1] * P4_Z[0][1] - P4_Z[1][1] * P4_Z[1][1] - P4_Z[2][1] * P4_Z[2][1]);
 	mass1=SetParticleMass(ID_l).first;
 	mass2=SetParticleMass(ID_l).second;
 	
diff --git a/Generators/Prophecy4fControl/bin/DRM_Transf.cxx b/Generators/Prophecy4fControl/bin/DRM_Transf.cxx
index 5fe60e00b146777cfff68473ba477a44f0c50d41..581de46b787199b8e526be887d67e0d362b3c706 100644
--- a/Generators/Prophecy4fControl/bin/DRM_Transf.cxx
+++ b/Generators/Prophecy4fControl/bin/DRM_Transf.cxx
@@ -88,7 +88,7 @@ double DRM::alupcm(double em0, double em1, double em2){
     ret_val = 0.f;
   }
   else{
-    ret_val = sqrt((em0 + emd) * (em0 - emd) * (em0 + ems) * (em0 - ems)) * .5f / em0;
+    ret_val = std::sqrt((em0 + emd) * (em0 - emd) * (em0 + ems) * (em0 - ems)) * .5f / em0;
   }
   return ret_val;
   
@@ -123,8 +123,8 @@ int DRM::rescms(double *p, double *p1, double *p2, double m1, double m2){
     po2[il] = pcm / pcmo * po2[il];
   }
   
-  po1[3] = sqrt(pcm*pcm + m1*m1);
-  po2[3] = sqrt(pcm*pcm + m2*m2);
+  po1[3] = std::sqrt(pcm*pcm + m1*m1);
+  po2[3] = std::sqrt(pcm*pcm + m2*m2);
   po1[4] = m1;
   po2[4] = m2;
   
diff --git a/Generators/Pythia8B_i/Pythia8B_i/UserSelections.h b/Generators/Pythia8B_i/Pythia8B_i/UserSelections.h
index 0774ae030af9aeb2cb4a8c939f6bdc1a103fd0b8..7bc39f5ed693ab02489243a110c5c42e1b8f5518 100644
--- a/Generators/Pythia8B_i/Pythia8B_i/UserSelections.h
+++ b/Generators/Pythia8B_i/Pythia8B_i/UserSelections.h
@@ -117,7 +117,7 @@ double BsJpsiPhi_PDF(double *params, double *x, bool useHelicity) {
 
 
   // Tagged analysis
-  if( fabs(tagprob - 0.5) > 1e-6 ){   
+  if( std::abs(tagprob - 0.5) > 1e-6 ){   
 
 
     ExpGSSinMT = exp(-time * GammaS) * sin(DeltaM * time);
@@ -380,7 +380,7 @@ bool Pythia8B_i::userSelection(Pythia8::Event &event, std::string userString,
 		for (int i = 0; i < eventSize; i++) {
 
 			int pID = event[i].id();
-			if (abs(pID) == 531) { //NOTE THIS WILL FIND BS AND ANTIBS
+			if (std::abs(pID) == 531) { //NOTE THIS WILL FIND BS AND ANTIBS
 				i_Bs = i;
 				std::vector<int> daughterlist = event.daughterList(i);
 
@@ -564,7 +564,7 @@ bool Pythia8B_i::userSelection(Pythia8::Event &event, std::string userString,
 		for (int i = 0; i < eventSize; i++) {
 
 			const int pID = event[i].id();
-			if (abs(pID) == 511) { //NOTE THIS FIND BD and Anti-Bd
+			if (std::abs(pID) == 511) { //NOTE THIS FIND BD and Anti-Bd
 				i_Bd = i;
 				std::vector<int> daughterlist = event.daughterList(i);
 
@@ -580,11 +580,11 @@ bool Pythia8B_i::userSelection(Pythia8::Event &event, std::string userString,
 					isjpsi = true;
 					i_Jpsi = daughterlist[1];
 				}
-				if (abs(event[daughterlist[0]].id()) == 313) { //This will find kstar or KstarBar
+				if (std::abs(event[daughterlist[0]].id()) == 313) { //This will find kstar or KstarBar
 					iskstar = true;
 					i_Kstar = daughterlist[0];
 				}
-				if (abs(event[daughterlist[1]].id()) == 313) { //This will find kstar or KstarBar
+				if (std::abs(event[daughterlist[1]].id()) == 313) { //This will find kstar or KstarBar
 					iskstar = true;
 					i_Kstar = daughterlist[1];
 				}
@@ -610,9 +610,9 @@ bool Pythia8B_i::userSelection(Pythia8::Event &event, std::string userString,
 				else
 					i_Muplus = 0;
 
-				if (abs(event[daughterlistKstar[0]].id()) == 321)
+				if (std::abs(event[daughterlistKstar[0]].id()) == 321)
 					i_Kplus = daughterlistKstar[0];
-				else if (abs(event[daughterlistKstar[1]].id()) == 321)
+				else if (std::abs(event[daughterlistKstar[1]].id()) == 321)
 					i_Kplus = daughterlistKstar[1];
 				else
 					i_Kplus = 0;
diff --git a/Generators/Pythia8B_i/src/Pythia8B_i.cxx b/Generators/Pythia8B_i/src/Pythia8B_i.cxx
index ccaf8ea9d37c3aef287e82a3132f270afd0787cc..f980808d7b046953f8fdf8fc336eefd9dc54b49e 100644
--- a/Generators/Pythia8B_i/src/Pythia8B_i.cxx
+++ b/Generators/Pythia8B_i/src/Pythia8B_i.cxx
@@ -193,7 +193,7 @@ StatusCode Pythia8B_i::callGenerator(){
             if ( (isBQuark && m_selectBQuarks) || ((isCQuark && m_selectCQuarks)) ) {
                 bool passesPtCut(false); bool passesEtaCut(false);
                 std::string accString = " : REJECTED";
-                double qpt = event[i].pT(); double qeta = fabs(event[i].eta());
+                double qpt = event[i].pT(); double qeta = std::abs(event[i].eta());
                 if (qpt>m_qPtCut) passesPtCut=true;
                 if (qeta<m_qEtaCut) passesEtaCut=true;
                 if (passesPtCut && passesEtaCut) {
@@ -210,7 +210,7 @@ StatusCode Pythia8B_i::callGenerator(){
             if ( (isAntiBQuark && m_selectBQuarks) || ((isAntiCQuark && m_selectCQuarks)) ) {
                 bool passesPtCut(false); bool passesEtaCut(false);
                 std::string accString = " : REJECTED";
-                double aqpt = event[i].pT(); double aqeta = fabs(event[i].eta());
+                double aqpt = event[i].pT(); double aqeta = std::abs(event[i].eta());
                 if (aqpt>m_aqPtCut) passesPtCut=true;
                 if (aqeta<m_aqEtaCut) passesEtaCut=true;
                 if (passesPtCut && passesEtaCut) {
@@ -489,7 +489,7 @@ bool Pythia8B_i::leptonSelect(Pythia8::Event &theEvent, std::vector<double> ptCu
             double eta = theParticle.eta();
             ATH_MSG_DEBUG("Lepton of type " << id << " with pt/eta " << pt << "/" << eta);
             for (int cutCntr=0; cutCntr<nCuts; ++cutCntr) {
-                if ( (pt>ptCut[cutCntr]) && (fabs(eta)<etaCut) ) {
+                if ( (pt>ptCut[cutCntr]) && (std::abs(eta)<etaCut) ) {
                     countGood[cutCntr] += 1;
                     leptonIDs.push_back(i); // remember leptons
                 }
@@ -555,17 +555,17 @@ bool Pythia8B_i::pairProperties(Pythia8::Event &theEvent, std::vector<int> lepto
             double py1=theEvent[*iit].py();
             double pz1=theEvent[*iit].pz();
             double mass1=theEvent[*iit].mSel();
-            double e1=sqrt(px1*px1+py1*py1+pz1*pz1+mass1*mass1);
+            double e1=std::sqrt(px1*px1+py1*py1+pz1*pz1+mass1*mass1);
             double px2=theEvent[*iit2].px();
             double py2=theEvent[*iit2].py();
             double pz2=theEvent[*iit2].pz();
             double mass2=theEvent[*iit2].mSel();
-            double e2=sqrt(px2*px2+py2*py2+pz2*pz2+mass2*mass2);
+            double e2=std::sqrt(px2*px2+py2*py2+pz2*pz2+mass2*mass2);
             double eSum=e1+e2;
             double pxSum=px1+px2;
             double pySum=py1+py2;
             double pzSum=pz1+pz2;
-            double M=sqrt(eSum*eSum-pxSum*pxSum-pySum*pySum-pzSum*pzSum);
+            double M=std::sqrt(eSum*eSum-pxSum*pxSum-pySum*pySum-pzSum*pzSum);
             if (M>massCut) {
                 passesCuts=true;
                 ATH_MSG_DEBUG("Acceptable lepton pair with invariant mass : " << M);
@@ -635,7 +635,7 @@ bool Pythia8B_i::passesCuts(std::vector<Pythia8::Particle> theParticles, std::ve
     unsigned int i(0);
     for (pItr=theParticles.begin(); pItr!=theParticles.end(); ++pItr,++i) {
         if (cutType=="PT") {if ((*pItr).pT() < cuts[i]) pass = false;}
-        if (cutType=="ETA") {if (fabs((*pItr).eta()) > cuts[i]) pass = false;}
+        if (cutType=="ETA") {if (std::abs((*pItr).eta()) > cuts[i]) pass = false;}
         if (!pass) break;
     }
     
diff --git a/Generators/Pythia8_i/src/Pythia8_i.cxx b/Generators/Pythia8_i/src/Pythia8_i.cxx
index 0d9ccc5ca737dacf2a0fe2e090edcadc28f52429..c7ddc100abb67a589430fec655a2d49093c8fb9f 100644
--- a/Generators/Pythia8_i/src/Pythia8_i.cxx
+++ b/Generators/Pythia8_i/src/Pythia8_i.cxx
@@ -406,7 +406,7 @@ StatusCode Pythia8_i::callGenerator(){
   double eventWeight = m_pythia->info.mergingWeight()*m_pythia->info.weight();
   
   if(returnCode != StatusCode::FAILURE &&
-     (fabs(eventWeight) < 1.e-18 ||
+     (std::abs(eventWeight) < 1.e-18 ||
       m_pythia->event.size() < 2)){
        
        returnCode = this->callGenerator();
diff --git a/Generators/Pythia8_i/src/UserHooks/GravFlat.cxx b/Generators/Pythia8_i/src/UserHooks/GravFlat.cxx
index c7acad93b99a67f304a2dc473468c511e8d141ce..ce332a3ecb40a2053357b213eaf229f659e614ab 100644
--- a/Generators/Pythia8_i/src/UserHooks/GravFlat.cxx
+++ b/Generators/Pythia8_i/src/UserHooks/GravFlat.cxx
@@ -50,7 +50,7 @@ namespace Pythia8 {
       double weightBW = pow2(sHat - m2Res) + pow2(sHat * GamMRat);
       
       double weightPL = 1;
-      double rH = sqrt(sHat);
+      double rH = std::sqrt(sHat);
       
       double weight=1;
       switch(m_energyMode(settingsPtr)){
diff --git a/Generators/Pythia8_i/src/UserHooks/SingleTopWideEta.cxx b/Generators/Pythia8_i/src/UserHooks/SingleTopWideEta.cxx
index 16ba8e6cc0351ce5404954d472dd9ba6ac453772..02727fff264d45b558751e97d5566cbb9c86b868 100644
--- a/Generators/Pythia8_i/src/UserHooks/SingleTopWideEta.cxx
+++ b/Generators/Pythia8_i/src/UserHooks/SingleTopWideEta.cxx
@@ -37,7 +37,7 @@ namespace Pythia8 {
       
       double sHat = phaseSpacePtr->sHat();
       double flatEta= 1.;
-      double rH = sqrt(sHat);
+      double rH = std::sqrt(sHat);
 
       if(rH <= 160.){
         double c = -5.55578e+01;
diff --git a/Generators/Pythia8_i/src/UserHooks/WprimeFlat.cxx b/Generators/Pythia8_i/src/UserHooks/WprimeFlat.cxx
index 472f7a1bfc4aacd5341ee8f3b8a050991a347ed3..5cd9eb68b497c03764e451b6024be3bd5a6f74f0 100644
--- a/Generators/Pythia8_i/src/UserHooks/WprimeFlat.cxx
+++ b/Generators/Pythia8_i/src/UserHooks/WprimeFlat.cxx
@@ -47,7 +47,7 @@ namespace Pythia8 {
       double GamMRat = wRes/mRes;
       double sHat = phaseSpacePtr->sHat();
       double weightBW = pow2(sHat - m2Res) + pow2(sHat * GamMRat);      
-      double m = sqrt(sHat)/((double)m_energyMode(settingsPtr)*1000.0);
+      double m = std::sqrt(sHat)/((double)m_energyMode(settingsPtr)*1000.0);
 
       switch(m_energyMode(settingsPtr)){
       case 8:
diff --git a/Generators/Pythia8_i/src/UserHooks/WprimeWZFlat.cxx b/Generators/Pythia8_i/src/UserHooks/WprimeWZFlat.cxx
index c27743d2839012872a7dbc620a04c17307a33ab4..1c61b8296b3beaf36d3b4a8b1598b68566f2ac84 100644
--- a/Generators/Pythia8_i/src/UserHooks/WprimeWZFlat.cxx
+++ b/Generators/Pythia8_i/src/UserHooks/WprimeWZFlat.cxx
@@ -45,7 +45,7 @@ namespace Pythia8 {
       double sHat = phaseSpacePtr->sHat();
       double weightBW = m2Res*m2Res + sHat*sHat*(1 + gamMRat*gamMRat) - 2.*sHat*m2Res;      
       
-      return weightBW * breitWignerDenom(sqrt(sHat)/8000.0);
+      return weightBW * breitWignerDenom(std::sqrt(sHat)/8000.0);
     }
     
   private:
diff --git a/Generators/TrackRecordGenerator/src/TrackRecordGenerator.cxx b/Generators/TrackRecordGenerator/src/TrackRecordGenerator.cxx
index 7cff32d53711289f15e0431672da6f4136b0fc73..3d940788ef0468b46b279a1206da32b4a10e219a 100644
--- a/Generators/TrackRecordGenerator/src/TrackRecordGenerator.cxx
+++ b/Generators/TrackRecordGenerator/src/TrackRecordGenerator.cxx
@@ -82,10 +82,10 @@ StatusCode TrackRecordGenerator::callGenerator() {
         particle4Position.setY( particle4Position.y() + CLHEP::RandFlat::shoot(&randomEngine(), -m_smearTR, m_smearTR) );
       } else {
         particle4Position.setZ( particle4Position.z() + CLHEP::RandFlat::shoot(&randomEngine(), -m_smearTR, m_smearTR) );
-        double R = sqrt( pow( particle4Position.x(),2 ) + pow(particle4Position.y(),2 ) );
-        double dPhi = atan2( m_smearTR, R );
+        double R = std::sqrt( std::pow( particle4Position.x(),2 ) + std::pow(particle4Position.y(),2 ) );
+        double dPhi = std::atan2( m_smearTR, R );
         dPhi = CLHEP::RandFlat::shoot( &randomEngine(), -dPhi, dPhi );
-        double theta = atan2( particle4Position.x() , particle4Position.y() );
+        double theta = std::atan2( particle4Position.x() , particle4Position.y() );
         particle4Position.setX( R*sin( theta + dPhi ) );
         particle4Position.setY( R*cos( theta + dPhi ) );
       }