+Double_t AliKalmanTrack::
+MeanMaterialBudgetNew(Double_t *start, Double_t *end, Double_t *mparam) {
+ //
+ // Calculate mean material budget and material properties between
+ // the points "start" and "end".
+ //
+ // "mparam" - parameters used for the energy and multiple scattering
+ // corrections:
+ //
+ // mparam[0] - mean density: sum(x_i*rho_i)/sum(x_i) [g/cm3]
+ // mparam[1] - equivalent rad length fraction: sum(x_i/X0_i) [adimensional]
+ // mparam[2] - mean A: sum(x_i*A_i)/sum(x_i) [adimensional]
+ // mparam[3] - mean Z: sum(x_i*Z_i)/sum(x_i) [adimensional]
+ // mparam[4] - length: sum(x_i) [cm]
+ // mparam[5] - Z/A mean: sum(x_i*Z_i/A_i)/sum(x_i) [adimensional]
+ // mparam[6] - number of boundary crosses
+ //
+
+ mparam[0]=0; mparam[1]=1; mparam[2] =0; mparam[3] =0;
+ mparam[4]=0; mparam[5]=0; mparam[6]=0;
+ //
+ Double_t bparam[6]; // total parameters
+ Double_t lparam[6]; // local parameters
+
+ for (Int_t i=0;i<6;i++) bparam[i]=0;
+
+ if (!gGeoManager) {
+ printf("ERROR: no TGeo\n");
+ return 0.;
+ }
+ //
+ Double_t length;
+ Double_t dir[3];
+ length = TMath::Sqrt((end[0]-start[0])*(end[0]-start[0])+
+ (end[1]-start[1])*(end[1]-start[1])+
+ (end[2]-start[2])*(end[2]-start[2]));
+ mparam[4]=length;
+ if (length<TGeoShape::Tolerance()) return 0.0;
+ Double_t invlen = 1./length;
+ dir[0] = (end[0]-start[0])*invlen;
+ dir[1] = (end[1]-start[1])*invlen;
+ dir[2] = (end[2]-start[2])*invlen;
+
+ // Initialize start point and direction
+ TGeoNode *currentnode = 0;
+ TGeoNode *startnode = gGeoManager->InitTrack(start, dir);
+ //printf("%s length=%f\n",gGeoManager->GetPath(),length);
+ if (!startnode) {
+ printf("ERROR: start point out of geometry\n");
+ return 0.0;
+ }
+ TGeoMaterial *material = startnode->GetVolume()->GetMedium()->GetMaterial();
+ lparam[0] = material->GetDensity();
+ lparam[1] = material->GetRadLen();
+ lparam[2] = material->GetA();
+ lparam[3] = material->GetZ();
+ lparam[4] = length;
+ lparam[5] = lparam[3]/lparam[2];
+ if (material->IsMixture()) {
+ TGeoMixture * mixture = (TGeoMixture*)material;
+ lparam[5] =0;
+ Double_t sum =0;
+ for (Int_t iel=0;iel<mixture->GetNelements();iel++){
+ sum += mixture->GetWmixt()[iel];
+ lparam[5]+= mixture->GetZmixt()[iel]*mixture->GetWmixt()[iel]/mixture->GetAmixt()[iel];
+ }
+ lparam[5]/=sum;
+ }
+
+ // Locate next boundary within length without computing safety.
+ // Propagate either with length (if no boundary found) or just cross boundary
+ gGeoManager->FindNextBoundaryAndStep(length, kFALSE);
+ Double_t step = 0.0; // Step made
+ Double_t snext = gGeoManager->GetStep();
+ // If no boundary within proposed length, return current density
+ if (!gGeoManager->IsOnBoundary()) {
+ mparam[0] = lparam[0];
+ mparam[1] = lparam[4]/lparam[1];
+ mparam[2] = lparam[2];
+ mparam[3] = lparam[3];
+ mparam[4] = lparam[4];
+ return lparam[0];
+ }
+ // Try to cross the boundary and see what is next
+ Int_t nzero = 0;
+ while (length>TGeoShape::Tolerance()) {
+ currentnode = gGeoManager->GetCurrentNode();
+ if (snext<2.*TGeoShape::Tolerance()) nzero++;
+ else nzero = 0;
+ if (nzero>3) {
+ // This means navigation has problems on one boundary
+ // Try to cross by making a small step
+ printf("ERROR: cannot cross boundary\n");
+ mparam[0] = bparam[0]/step;
+ mparam[1] = bparam[1];
+ mparam[2] = bparam[2]/step;
+ mparam[3] = bparam[3]/step;
+ mparam[5] = bparam[5]/step;
+ mparam[4] = step;
+ mparam[0] = 0.; // if crash of navigation take mean density 0
+ mparam[1] = 1000000; // and infinite rad length
+ return bparam[0]/step;
+ }
+ mparam[6]+=1.;
+ step += snext;
+ bparam[1] += snext/lparam[1];
+ bparam[2] += snext*lparam[2];
+ bparam[3] += snext*lparam[3];
+ bparam[5] += snext*lparam[5];
+ bparam[0] += snext*lparam[0];
+
+ if (snext>=length) break;
+ if (!currentnode) break;
+ length -= snext;
+ //printf("%s snext=%f length=%f\n", currentnode->GetName(),snext,length);
+ material = currentnode->GetVolume()->GetMedium()->GetMaterial();
+ lparam[0] = material->GetDensity();
+ lparam[1] = material->GetRadLen();
+ lparam[2] = material->GetA();
+ lparam[3] = material->GetZ();
+ //printf(" %f %f %f %f\n",lparam[0],lparam[1],lparam[2],lparam[3]);
+ lparam[5] = lparam[3]/lparam[2];
+ if (material->IsMixture()) {
+ TGeoMixture * mixture = (TGeoMixture*)material;
+ lparam[5]=0;
+ Double_t sum =0;
+ for (Int_t iel=0;iel<mixture->GetNelements();iel++){
+ sum+= mixture->GetWmixt()[iel];
+ lparam[5]+= mixture->GetZmixt()[iel]*mixture->GetWmixt()[iel]/mixture->GetAmixt()[iel];
+ }
+ lparam[5]/=sum;
+ }
+ gGeoManager->FindNextBoundaryAndStep(length, kFALSE);
+ snext = gGeoManager->GetStep();
+ //printf("snext %f\n",snext);
+ }
+ mparam[0] = bparam[0]/step;
+ mparam[1] = bparam[1];
+ mparam[2] = bparam[2]/step;
+ mparam[3] = bparam[3]/step;
+ mparam[5] = bparam[5]/step;
+ return bparam[0]/step;
+}
+
+