Fixed a bug in the LF calculations and parallelized the chi^2 calculations in single-histogram and asymmetry fits

src/classes/PRunAsymmetry.cpp

@@ -29,6 +29,14 @@
  *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
  ***************************************************************************/
 
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#ifdef HAVE_GOMP
+#include <omp.h>
+#endif
+
 #include <stdio.h>
 
 #include <iostream>
@@ -154,9 +162,20 @@ Double_t PRunAsymmetry::CalcChiSquare(const std::vector<Double_t>& par)
     fFuncValues[i] = fMsrInfo->EvalFunc(fMsrInfo->GetFuncNo(i), *fRunInfo->GetMap(), par);
   }
 
-  // calculate chisq
-  Double_t time;
-  for (UInt_t i=0; i<fData.GetValue()->size(); i++) {
+  // calculate chi square
+  Double_t time(1.0);
+  Int_t i, N(static_cast<Int_t>(fData.GetValue()->size()));
+
+  // Calculate the theory function once to ensure one function evaluation for the current set of parameters.
+  // This is needed for the LF and user functions where some non-thread-save calculations only need to be calculated once
+  // for a given set of parameters---which should be done outside of the parallelized loop.
+  // For all other functions it means a tiny and acceptable overhead.
+  asymFcnValue = fTheory->Func(time, par, fFuncValues);
+
+  #ifdef HAVE_GOMP
+  #pragma omp parallel for default(shared) private(i,time,diff,asymFcnValue) schedule(dynamic,N/(2*omp_get_num_procs())) reduction(+:chisq)
+  #endif
+  for (i=0; i < N; ++i) {
     time = fData.GetDataTimeStart() + (Double_t)i*fData.GetDataTimeStep();
     if ((time>=fFitStartTime) && (time<=fFitEndTime)) {
       switch (fAlphaBetaTag) {