update path_init() to check for a divide by zero

This commit updates path_init() to check that beta > 0 before dividing by it to
compute the time. Previously when fitting electrons it would occasionally
divide by zero which would cause the inf to propagate all the way through the
likelihood function.

1 files changed, 4 insertions, 1 deletions

diff --git a/src/path.c b/src/path.c
index 340f8c7..85233d6 100644
--- a/src/path.c
+++ b/src/path.c
@@ -84,7 +84,10 @@ path *path_init(double *pos, double *dir, double T0, double range, double theta0
             dz[i] = (s[i]-s[i-1])*cos(theta);
 
             /* Calculate total energy */
-            t[i] = t[i-1] + (s[i]-s[i-1])/(beta[i]*SPEED_OF_LIGHT);
+            if (beta[i] > 0)
+                t[i] = t[i-1] + (s[i]-s[i-1])/(beta[i]*SPEED_OF_LIGHT);
+            else
+                t[i] = t[i-1];
 
             x[i] = x[i-1] + dx[i];
             y[i] = y[i-1] + dy[i];