Access to AliRoot magnetic field map.
[u/mrichter/AliRoot.git] / 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