File indexing completed on 2024-04-06 12:23:25
0001 #include "PhysicsTools/HepMCCandAlgos/interface/PDFWeightsHelper.h"
0002 #include "FWCore/MessageLogger/interface/MessageLogger.h"
0003 #include <fstream>
0004
0005 PDFWeightsHelper::PDFWeightsHelper() {}
0006
0007 void PDFWeightsHelper::Init(unsigned int nreplicas, unsigned int neigenvectors, const edm::FileInPath &incsv) {
0008 transformation_.resize(nreplicas, neigenvectors);
0009
0010 std::ifstream instream(incsv.fullPath());
0011 if (!instream.is_open()) {
0012 throw cms::Exception("PDFWeightsHelper") << "Could not open csv file" << incsv.relativePath();
0013 }
0014
0015 for (unsigned int ireplica = 0; ireplica < nreplicas; ++ireplica) {
0016 std::string linestr;
0017 getline(instream, linestr);
0018 std::istringstream line(linestr);
0019 for (unsigned int ieigen = 0; ieigen < neigenvectors; ++ieigen) {
0020 std::string valstr;
0021 getline(line, valstr, ',');
0022 std::istringstream val(valstr);
0023 val >> transformation_(ireplica, ieigen);
0024 }
0025 }
0026 }
0027
0028 void PDFWeightsHelper::DoMC2Hessian(double nomweight, const double *inweights, double *outweights) const {
0029 const unsigned int nreplicas = transformation_.rows();
0030 const unsigned int neigenvectors = transformation_.cols();
0031
0032 Eigen::VectorXd inweightv(nreplicas);
0033 for (unsigned int irep = 0; irep < nreplicas; ++irep) {
0034 inweightv[irep] = inweights[irep] - nomweight;
0035 }
0036
0037 Eigen::VectorXd outweightv = transformation_.transpose() * inweightv;
0038
0039 for (unsigned int ieig = 0; ieig < neigenvectors; ++ieig) {
0040 outweights[ieig] = outweightv[ieig] + nomweight;
0041 }
0042 }
