From 38a63ec3ea6f757536ce30fd442a967f3ef90537 Mon Sep 17 00:00:00 2001
From: Stewart Martin-Haugh <stewart.martin-haugh@cern.ch>
Date: Fri, 29 Sep 2023 18:08:23 +0200
Subject: [PATCH] Use identity to reduce number of calls to log functions in
tracking calculations
Use identity to reduce number of calls to log functions in tracking calculations
---
Tools/PROCTools/data/q449_AOD_digest.ref | 2 +-
Tools/WorkflowTestRunner/python/References.py | 8 ++---
.../TrkExUtils/src/MaterialInteraction.cxx | 30 +++++++++++--------
3 files changed, 22 insertions(+), 18 deletions(-)
diff --git a/Tools/PROCTools/data/q449_AOD_digest.ref b/Tools/PROCTools/data/q449_AOD_digest.ref
index 9d48865b79f..a4cf64b380a 100644
--- a/Tools/PROCTools/data/q449_AOD_digest.ref
+++ b/Tools/PROCTools/data/q449_AOD_digest.ref
@@ -19,7 +19,7 @@
431493 1096123504 258 340 52 5 0 8 0 8 11 0 11
431493 1096125003 349 449 84 7 0 10 0 10 17 0 17
431493 1096125237 355 495 76 6 1 8 0 8 15 0 15
- 431493 1096125348 295 346 63 6 2 8 0 8 8 0 8
+ 431493 1096125348 295 346 63 6 1 8 0 8 8 0 8
431493 1096125522 251 303 64 9 1 7 0 7 16 0 16
431493 1096127413 396 579 105 7 1 11 0 11 22 0 22
431493 1096127722 221 418 74 9 1 7 0 7 7 0 7
diff --git a/Tools/WorkflowTestRunner/python/References.py b/Tools/WorkflowTestRunner/python/References.py
index ad7c13f9f3c..d6a9ab82d8a 100644
--- a/Tools/WorkflowTestRunner/python/References.py
+++ b/Tools/WorkflowTestRunner/python/References.py
@@ -22,10 +22,10 @@ references_map = {
"d1726": "v1",
"d1759": "v3",
# Reco
- "q442": "v22",
- "q443": "v18",
- "q445": "v26",
- "q449": "v30",
+ "q442": "v23",
+ "q443": "v19",
+ "q445": "v27",
+ "q449": "v31",
# Derivations
"data_PHYS_Run2": "v11",
"data_PHYS_Run3": "v10",
diff --git a/Tracking/TrkExtrapolation/TrkExUtils/src/MaterialInteraction.cxx b/Tracking/TrkExtrapolation/TrkExUtils/src/MaterialInteraction.cxx
index fc6323a73d8..59123ab10c8 100644
--- a/Tracking/TrkExtrapolation/TrkExUtils/src/MaterialInteraction.cxx
+++ b/Tracking/TrkExtrapolation/TrkExUtils/src/MaterialInteraction.cxx
@@ -68,7 +68,7 @@ MeanExcitationEnergy(const Trk::Material& mat) {
[[gnu::always_inline]]
#endif
inline double
-DensityEffect(const double zOverAtimesRho, const double eta2,
+DensityEffect(const double zOverAtimesRho, const double eta,
const double gamma, const double I) {
// density effect. Done for gamma > 10 ( p > 1GeV for muons)
@@ -78,7 +78,10 @@ DensityEffect(const double zOverAtimesRho, const double eta2,
// PDG 2022 Table 34.1
double eplasma = 28.816e-6 * std::sqrt(1000. * zOverAtimesRho);
// PDG 2022 Eq. 34.6
- return 2. * std::log(eplasma / I) + std::log(eta2) - 1.;
+ //2. * std::log(eplasma / I) + std::log(eta2) - 1.
+ //applying logarithmic identities becomes
+ // 2*(log(eplasma/I) + log(eta)) = 2*log(eplasma*eta/I)
+ return 2. * std::log(eplasma*eta / I) - 1.;
}
return 0;
}
@@ -99,7 +102,9 @@ inline double
LandauMPV(const double kazL, const double eta2, const double I,
const double beta, const double delta) {
// PDG 2022 Eq 34.12
- return -kazL * (std::log(2. * s_me * eta2 / I) + std::log(kazL / I) + 0.2 -
+ // then apply logarithmic identity
+ // log(2. * s_me * eta2 / I) + log(kazL / I) = log(2. * s_me* eta2 * kazL/(I*I))
+ return -kazL * (std::log(2. * s_me * eta2*kazL/(I*I)) + 0.2 -
(beta * beta) - delta);
}
@@ -138,9 +143,9 @@ double Trk::MaterialInteraction::dEdl_ionization(
// sigmaL --> FWHM of Landau
sigma = 4 * kaz;
} else {
- double eta2 = beta * gamma;
- eta2 *= eta2;
- const double delta = DensityEffect(zOverAtimesRho, eta2, gamma, I);
+ const double eta = beta * gamma;
+ const double eta2 = eta*eta;
+ const double delta = DensityEffect(zOverAtimesRho, eta, gamma, I);
// tmax - cut off energy
const double tMax =
2. * eta2 * s_me / (1. + 2. * gamma * mfrac + mfrac * mfrac);
@@ -175,9 +180,9 @@ double Trk::MaterialInteraction::dEdXBetheBloch(
double kaz = KAZ(mat.zOverAtimesRho());
if (particle != Trk::electron) {
- double eta2 = beta * gamma;
- eta2 *= eta2;
- double delta = DensityEffect(zOverAtimesRho, eta2, gamma, iPot);
+ const double eta = beta * gamma;
+ const double eta2 = eta*eta;
+ double delta = DensityEffect(zOverAtimesRho, eta, gamma, iPot);
// mass fraction
double mfrac = s_me / m;
// tmax - cut off energy
@@ -210,10 +215,9 @@ double Trk::MaterialInteraction::dE_MPV_ionization(
const double I = MeanExcitationEnergy(mat);
const double zOverAtimesRho = mat.zOverAtimesRho();
double kaz = KAZ(zOverAtimesRho);
- double eta2 = beta * gamma;
-
- eta2 *= eta2;
- const double delta = DensityEffect(zOverAtimesRho, eta2, gamma, I);
+ const double eta = beta * gamma;
+ const double eta2 = eta*eta;
+ const double delta = DensityEffect(zOverAtimesRho, eta, gamma, I);
// divide by beta^2 for non-electrons
kaz /= beta * beta;
kazL = kaz * path;
--
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