Correctly define the Ewald factor also when reading the table from a file.

examples/plot_gravity_checks.py

@@ -81,7 +81,10 @@ plt.figure()
 count = 0
 
 # Get the Gadget-2 data if existing
-gadget2_file_list = glob.glob("forcetest_gadget2.txt")
+if periodic:
+    gadget2_file_list = glob.glob("forcetest_gadget2_periodic.txt")
+else:
+    gadget2_file_list = glob.glob("forcetest_gadget2.txt")
 if len(gadget2_file_list) != 0:
 
     gadget2_data = np.loadtxt(gadget2_file_list[0])

src/gravity.c

@@ -145,9 +145,6 @@ void gravity_exact_force_ewald_init(double boxSize) {
     const float factor_cos = 2.f * M_PI;
     const float factor_pot = M_PI / alpha2;
 
-    /* Ewald factor to access the table */
-    ewald_fac = (double)(2 * Newald) / boxSize;
-
     /* Zero everything */
     bzero(fewald_x, (Newald + 1) * (Newald + 1) * (Newald + 1) * sizeof(float));
     bzero(fewald_y, (Newald + 1) * (Newald + 1) * (Newald + 1) * sizeof(float));
@@ -295,6 +292,9 @@ void gravity_exact_force_ewald_init(double boxSize) {
             clocks_from_ticks(getticks() - tic), clocks_getunit());
   }
 
+  /* Ewald factor to access the table */
+  ewald_fac = (double)(2 * Newald) / boxSize;
+
   /* Apply the box-size correction */
   for (int i = 0; i <= Newald; ++i) {
     for (int j = 0; j <= Newald; ++j) {
@@ -508,7 +508,7 @@ void gravity_exact_force_compute_mapper(void *map_data, int nr_gparts,
       /* Interact it with all other particles in the space.*/
       for (int j = 0; j < (int)s->nr_gparts; ++j) {
 
-        struct gpart *gpj = &s->gparts[j];
+        const struct gpart *gpj = &s->gparts[j];
 
         /* No self interaction */
         if (gpi == gpj) continue;