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This commit is contained in:
Gabriele Cosmo
2021-12-10 14:46:44 +01:00
committed by Ben Morgan
parent 6399a014b6
commit 80e2389dd8
3932 changed files with 202519 additions and 246221 deletions
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source/processes/electromagnetic/utils/src/G4EmElementSelector.cc
+25 -20
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@@ -117,7 +117,6 @@ void G4EmElementSelector::Initialise(const G4ParticleDefinition* part,
xSections[i]->PutValue(j, cross);
}
}
// xSections start from null, so use probabilities from the next bin
if(0.0 == (*xSections[nElmMinusOne])[0]) {
for (G4int i=0; i<=nElmMinusOne; ++i) {
@@ -141,39 +140,45 @@ void G4EmElementSelector::Initialise(const G4ParticleDefinition* part,
}
}
}
//G4cout << "======== G4EmElementSelector for the " << model->GetName()
// << G4endl;
/*
G4cout << "======== G4EmElementSelector for the " << model->GetName()
<< G4endl;
for (G4int i=0; i<=nElmMinusOne; ++i) {
G4cout << "#### i=" << i << G4endl;
G4cout << (*xSections[i]) << G4endl;
}
*/
}
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.....
const G4Element*
G4EmElementSelector::SelectRandomAtom(const G4double e, const G4double loge) const
const G4Element*
G4EmElementSelector::SelectRandomAtom(const G4double e,
const G4double loge) const
{
const G4Element* element = (*theElementVector)[nElmMinusOne];
if (nElmMinusOne > 0) {
// 1. Determine energy index (only once)
const size_t nBins = (xSections[0])->GetVectorLength();
// handle cases below/above the enrgy grid (by ekin, idx that gives a=0/1)
// ekin = x[0] if e<=x[0] and idx will be 0 ^ a=0 => so y=y0
// ekin = x[N-1] if e>=x[N-1] and idx will be N-2 ^ a=1 => so y=y_{N-1}
const G4double ekin = std::max((xSections[0])->Energy(0),
std::min((xSections[0])->Energy(nBins-1),e));
// compute the lower index of the bin (idx \in [0,N-2] will be guaranted)
const size_t idx = (xSections[0])->ComputeLogVectorBin(loge);
// 2. Do the linear interp.(robust for corner cases through ekin, idx and a)
const G4double x1 = (xSections[0])->Energy(idx);
const G4double x2 = (xSections[0])->Energy(idx+1);
// note: all corner cases of the previous methods are covered and eventually
// gives a=0/1 that results in y=y0\y_{N-1} if e<=x[0]/e>=x[N-1] or
// y=y_i/y_{i+1} if e<x[i]/e>=x[i+1] due to small numerical errors
const G4double a = std::max(0., std::min(1., (ekin - x1)/(x2 - x1)));
G4double ekin = e;
std::size_t idx = 0;
if(e <= (xSections[0])->Energy(0)) {
ekin = (xSections[0])->Energy(0);
} else if(e < (xSections[0])->GetMaxEnergy()) {
idx = (xSections[0])->ComputeLogVectorBin(loge);
} else {
ekin = (xSections[0])->GetMaxEnergy();
idx = (xSections[0])->GetVectorLength() - 2;
}
// 2. Do the linear interp.(corner cases are already excluded)
const G4double x1 = (xSections[0])->Energy(idx);
const G4double a = (ekin - x1)/((xSections[0])->Energy(idx+1) - x1);
const G4double urnd = G4UniformRand();
for (G4int i = 0; i < nElmMinusOne; ++i) {
const G4double y1 = (*xSections[i])[idx];
const G4double y2 = (*xSections[i])[idx+1];
if (urnd <= y1 + a*(y2-y1)) {
if (urnd <= y1 + a*((*xSections[i])[idx+1] - y1)) {
element = (*theElementVector)[i];
break;
}