update sno_charge.c

This commit adds lots of comments to sno_charge.c and makes a couple of other
changes:

- use interp1d() instead of the GSL interpolation routines
- increase MAX_PE to 100

I increased MAX_PE because I determined that it had a rather large impact on
the likelihood function for 500 MeV electrons. This unfortunately slows down
the initialization by a lot. I think I could speed this up by convolving the
single PE charge distribution with a gaussian *before* convolving the charge
distributions to compute the charge distributions for multiple PE.

1 files changed, 1 insertions, 3 deletions

diff --git a/src/test.c b/src/test.c
index a3f98a9..8bd0688 100644
--- a/src/test.c
+++ b/src/test.c
@@ -404,7 +404,7 @@ int test_solid_angle(char *err)
 static double sno_charge(double q, void *params)
 {
     int n = ((int *) params)[0];
-    return pq(q,n);
+    return get_pq(q,n);
 }
 
 int test_sno_charge_integral(char *err)
@@ -431,8 +431,6 @@ int test_sno_charge_integral(char *err)
         goto err;
     }
 
-    free_charge();
-
     gsl_integration_cquad_workspace_free(w);
 
     return 0;