From 300d785201e33646eced205d35b1c6bbac4932cd Mon Sep 17 00:00:00 2001
From: Elmar Ritsch <Elmar.Ritsch@cern.ch>
Date: Fri, 22 Apr 2016 14:52:01 +0200
Subject: [PATCH] Improve performance of heavily used BFieldCache::getB method
by moving short->float type conversions out of tight for-loop. New
BFieldCache::getB method is about 1.4 times faster. Bit-wise identical output
is guaranteed (MagFieldServices-00-01-36)
* Improve performance of heavily used BFieldCache::getB method by moving
short->float type conversions out of tight for-loop. New BFieldCache::getB
method is about 1.4 times faster.
* Bit-wise identical output is guaranteed
* Tagging as MagFieldServices-00-01-36
---
.../MagFieldServices/MagFieldServices/AtlasFieldSvc.h | 4 ++--
.../MagFieldServices/MagFieldServices/BFieldCache.h | 6 +++---
2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/MagneticField/MagFieldServices/MagFieldServices/AtlasFieldSvc.h b/MagneticField/MagFieldServices/MagFieldServices/AtlasFieldSvc.h
index 34fe1162b061..e191ea7179b5 100644
--- a/MagneticField/MagFieldServices/MagFieldServices/AtlasFieldSvc.h
+++ b/MagneticField/MagFieldServices/MagFieldServices/AtlasFieldSvc.h
@@ -67,8 +67,8 @@ namespace MagField {
/** get B field value at given position */
/** xyz[3] is in mm, bxyz[3] is in kT */
/** if deriv[9] is given, field derivatives are returned in kT/mm */
- virtual void getField(const double *xyz, double *bxyz, double *deriv = 0);
- virtual void getFieldZR(const double *xyz, double *bxyz, double *deriv = 0);
+ virtual void getField(const double *xyz, double *bxyz, double *deriv = 0) override final;
+ virtual void getFieldZR(const double *xyz, double *bxyz, double *deriv = 0) override final;
private:
/* // Methods called to get field
diff --git a/MagneticField/MagFieldServices/MagFieldServices/BFieldCache.h b/MagneticField/MagFieldServices/MagFieldServices/BFieldCache.h
index 31d3d3418dce..f97aeaa6a6b0 100644
--- a/MagneticField/MagFieldServices/MagFieldServices/BFieldCache.h
+++ b/MagneticField/MagFieldServices/MagFieldServices/BFieldCache.h
@@ -43,7 +43,7 @@ private:
double m_rmin, m_rmax; // bin range in r
double m_phimin, m_phimax; // bin range in phi
float m_invz, m_invr, m_invphi; // 1/(bin size) in z, r, phi
- short m_field[3][8]; // (Bz,Br,Bphi) at 8 corners of the bin
+ float m_field[3][8]; // (Bz,Br,Bphi) at 8 corners of the bin
float m_scale; // unit of m_field in kT
};
@@ -67,7 +67,7 @@ BFieldCache::getB( const double *xyz, double r, double phi, double *B, double *d
// interpolate field values in z, r, phi
float Bzrphi[3];
for ( int i = 0; i < 3; i++ ) { // z, r, phi components
- const short *field = m_field[i];
+ const float *field = m_field[i];
Bzrphi[i] = m_scale*( gz*( gr*( gphi*field[0] + fphi*field[1] ) +
fr*( gphi*field[2] + fphi*field[3] ) ) +
fz*( gr*( gphi*field[4] + fphi*field[5] ) +
@@ -95,7 +95,7 @@ BFieldCache::getB( const double *xyz, double r, double phi, double *B, double *d
float sphi = m_scale*m_invphi;
float dBdz[3], dBdr[3], dBdphi[3];
for ( int j = 0; j < 3; j++ ) { // Bz, Br, Bphi components
- const short *field = m_field[j];
+ const float *field = m_field[j];
dBdz[j] = sz*( gr*( gphi*(field[4]-field[0]) + fphi*(field[5]-field[1]) ) +
fr*( gphi*(field[6]-field[2]) + fphi*(field[7]-field[3]) ) );
dBdr[j] = sr*( gz*( gphi*(field[2]-field[0]) + fphi*(field[3]-field[1]) ) +
--
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