update muon kinetic energy calculation

This commit updates the calculation of the muon kinetic energy as a function of
distance along the track. Previously I was using an approximation from the PDG,
but it doesn't seem to be very accurate and won't generalize to the case of
electrons. The kinetic energy is now calculated using the tabulated values of
dE/dx as a function of energy.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/path.c b/src/path.c
index 478a609..2083dc1 100644
--- a/src/path.c
+++ b/src/path.c
@@ -31,7 +31,7 @@ double path_get_coefficient(unsigned int k, double *s, double *x, double theta0,
     return sum*pow(k-0.5,2)*pow(M_PI,2)/pow(theta0*range,2);
 }
 
-path *path_init(double *pos, double *dir, double T0, double range, double theta0, getKineticEnergyFunc *fun, double *z1, double *z2, size_t n, double m)
+path *path_init(double *pos, double *dir, double T0, double range, double theta0, getKineticEnergyFunc *fun, void *params, double *z1, double *z2, size_t n, double m)
 {
     size_t i, j;
     double E, mom, beta, theta, phi;
@@ -68,7 +68,7 @@ path *path_init(double *pos, double *dir, double T0, double range, double theta0
             theta1[i] += z1[j]*foo(s[i],range,theta0,j+1);
             theta2[i] += z2[j]*foo(s[i],range,theta0,j+1);
         }
-        T[i] = fun(s[i],T0);
+        T[i] = fun(s[i],params);
         if (i > 0) {
             theta = sqrt(theta1[i]*theta1[i] + theta2[i]*theta2[i]);
             phi = atan2(theta2[i],theta1[i]);