TFluka/magfld.cxx

   1 #include "AliRun.h"
   2 #include "AliMagF.h"
   3 #include "Fdblprc.h"  //(DBLPRC) fluka common
   4 //
   5 // #include "TCallf77.h"
   6
   7 #ifndef WIN32
   8 #define magfld magfld_
   9 #define type_of_call
  10 #else
  11 #define magfld MAGFLD
  12 #define type_of_call  _stdcall
  13 #endif
  14
  15 extern "C" void type_of_call magfld(double& x,   double& y,   double& z,
  16                                     double& btx, double& bty, double& btz, double& b,
  17                                     int&    nreg,int& idisc)
  18 {
  19
  20 /*
  21 *----------------------------------------------------------------------*
  22 *                                                                      *
  23 *                                                                      *
  24 *     Input variables:                                                 *
  25 *            x,y,z = current position                                  *
  26 *            nreg  = current region                                    *
  27 *     Output variables:                                                *
  28 *            btx,bty,btz = cosines of the magn. field vector           *
  29 *            B = magnetic field intensity (Tesla)                      *
  30 *            idisc = set to 1 if the particle has to be discarded      *
  31 *                                                                      *
  32 *----------------------------------------------------------------------*
  33 */
  34
  35     printf("\n ========> magfld\n");
  36
  37
  38     idisc = 0;
  39
  40     Float_t bc[3];
  41     Float_t xc[3];
  42
  43     xc[1] = x;
  44     xc[0] = y;
  45     xc[2] = z;
  46
  47
  48
  49     gAlice->Field()->Field(xc, bc);
  50
  51     b = sqrt(bc[0] * bc[0] + bc[1] * bc[1] + bc[2] * bc[2]);
  52     if (b) {
  53         btx = bc[1]/b;
  54         bty = bc[0]/b;
  55         Double_t btt = btx * btx + bty * bty;
  56         if (btt >= (Double_t) 1.) {
  57             btx /= TMath::Sqrt(btt);
  58             bty /= TMath::Sqrt(btt);
  59             b   /= TMath::Sqrt(btt);
  60             btz =  (Double_t) 0.;
  61         } else {
  62             btz = TMath::Sqrt((Double_t) 1. -  btt);
  63         }
  64     } else {
  65         btx = 0.;
  66         bty = 0.;
  67         btz = 1.;
  68     }
  69
  70     // from kG to T
  71     b /= (Double_t) 10.;
  72     printf("\n #magfld: x, y, z, btx, bty, btz, b %f %f %f %f %f %f %f \n",
  73            x, y, z, btx, bty, btz, b);
  74 }