Test comoving distance functions in testCosmology

tests/testCosmology.c

@@ -56,7 +56,7 @@ int main(int argc, char *argv[]) {
   struct cosmology cosmo;
   cosmology_init(&params, &us, &phys_const, &cosmo);
 
-  message("Start checking computation...");
+  message("Start checking time since big bang computation...");
 
   for (int i = 0; i < N_CHECK; i++) {
     double a = 0.1 + 0.9 * i / (N_CHECK - 1.);
@@ -70,6 +70,20 @@ int main(int argc, char *argv[]) {
     assert(fabs(tmp) < TOLERANCE);
   }
 
+  message("Start checking comoving distance computation...");
+
+  for (int i = 0; i < N_CHECK; i++) {
+    double a = 0.1 + 0.9 * i / (N_CHECK - 1.);
+    /* Compute a(comoving_distance(a)) and check if same results */
+    double tmp = cosmology_get_comoving_distance(&cosmo, a);
+    tmp = cosmology_scale_factor_at_comoving_distance(&cosmo, tmp);
+
+    /* check accuracy */
+    tmp = (tmp - a) / a;
+    message("Accuracy of %g at a=%g", tmp, a);
+    assert(fabs(tmp) < TOLERANCE);
+  }
+
   message("Everything seems fine with cosmology.");
 
   cosmology_clean(&cosmo);