Only read the gravity mesh related quantites if we are running with periodic BCs.

examples/main.c

@@ -681,6 +681,28 @@ int main(int argc, char *argv[]) {
       phys_const_print(&prog_const);
     }
 
+    /* Read particles and space information from ICs */
+    char ICfileName[200] = "";
+    parser_get_param_string(params, "InitialConditions:file_name", ICfileName);
+    const int periodic =
+        parser_get_param_int(params, "InitialConditions:periodic");
+    const int replicate =
+        parser_get_opt_param_int(params, "InitialConditions:replicate", 1);
+    clean_smoothing_length_values = parser_get_opt_param_int(
+        params, "InitialConditions:cleanup_smoothing_lengths", 0);
+    const int cleanup_h = parser_get_opt_param_int(
+        params, "InitialConditions:cleanup_h_factors", 0);
+    const int cleanup_sqrt_a = parser_get_opt_param_int(
+        params, "InitialConditions:cleanup_velocity_factors", 0);
+    const int generate_gas_in_ics = parser_get_opt_param_int(
+        params, "InitialConditions:generate_gas_in_ics", 0);
+
+    /* Some checks that we are not doing something stupid */
+    if (generate_gas_in_ics && flag_entropy_ICs)
+      error("Can't generate gas if the entropy flag is set in the ICs.");
+    if (generate_gas_in_ics && !with_cosmology)
+      error("Can't generate gas if the run is not cosmological.");
+
     /* Initialise the cosmology */
     if (with_cosmology)
       cosmology_init(params, &us, &prog_const, &cosmo);
@@ -709,32 +731,11 @@ int main(int argc, char *argv[]) {
 
     /* Initialise the gravity properties */
     if (with_self_gravity)
-      gravity_props_init(&gravity_properties, params, &cosmo, with_cosmology);
+      gravity_props_init(&gravity_properties, params, &cosmo, with_cosmology,
+                         periodic);
     else
       bzero(&gravity_properties, sizeof(struct gravity_props));
 
-    /* Read particles and space information from ICs */
-    char ICfileName[200] = "";
-    parser_get_param_string(params, "InitialConditions:file_name", ICfileName);
-    const int periodic =
-        parser_get_param_int(params, "InitialConditions:periodic");
-    const int replicate =
-        parser_get_opt_param_int(params, "InitialConditions:replicate", 1);
-    clean_smoothing_length_values = parser_get_opt_param_int(
-        params, "InitialConditions:cleanup_smoothing_lengths", 0);
-    const int cleanup_h = parser_get_opt_param_int(
-        params, "InitialConditions:cleanup_h_factors", 0);
-    const int cleanup_sqrt_a = parser_get_opt_param_int(
-        params, "InitialConditions:cleanup_velocity_factors", 0);
-    const int generate_gas_in_ics = parser_get_opt_param_int(
-        params, "InitialConditions:generate_gas_in_ics", 0);
-
-    /* Some checks that we are not doing something stupid */
-    if (generate_gas_in_ics && flag_entropy_ICs)
-      error("Can't generate gas if the entropy flag is set in the ICs.");
-    if (generate_gas_in_ics && !with_cosmology)
-      error("Can't generate gas if the run is not cosmological.");
-
     /* Be verbose about what happens next */
     if (myrank == 0) message("Reading ICs from file '%s'", ICfileName);
     if (myrank == 0 && cleanup_h)

src/gravity_properties.c

@@ -39,7 +39,8 @@
 #define gravity_props_default_rebuild_frequency 0.01f
 
 void gravity_props_init(struct gravity_props *p, struct swift_params *params,
-                        const struct cosmology *cosmo, int with_cosmology) {
+                        const struct cosmology *cosmo, int with_cosmology,
+                        int periodic) {
 
   /* Tree updates */
   p->rebuild_frequency =
@@ -50,24 +51,31 @@ void gravity_props_init(struct gravity_props *p, struct swift_params *params,
     error("Invalid tree rebuild frequency. Must be in [0., 1.]");
 
   /* Tree-PM parameters */
-  p->mesh_size = parser_get_param_int(params, "Gravity:mesh_side_length");
-  p->a_smooth = parser_get_opt_param_float(params, "Gravity:a_smooth",
-                                           gravity_props_default_a_smooth);
-  p->r_cut_max_ratio = parser_get_opt_param_float(
-      params, "Gravity:r_cut_max", gravity_props_default_r_cut_max);
-  p->r_cut_min_ratio = parser_get_opt_param_float(
-      params, "Gravity:r_cut_min", gravity_props_default_r_cut_min);
-
-  /* Some basic checks */
-  if (p->mesh_size % 2 != 0)
-    error("The mesh side-length must be an even number.");
-
-  if (p->a_smooth <= 0.)
-    error("The mesh smoothing scale 'a_smooth' must be > 0.");
-
-  if (2. * p->a_smooth * p->r_cut_max_ratio > p->mesh_size)
-    error("Mesh too small given r_cut_max. Should be at least %d cells wide.",
-          (int)(2. * p->a_smooth * p->r_cut_max_ratio) + 1);
+  if (periodic) {
+    p->mesh_size = parser_get_param_int(params, "Gravity:mesh_side_length");
+    p->a_smooth = parser_get_opt_param_float(params, "Gravity:a_smooth",
+                                             gravity_props_default_a_smooth);
+    p->r_cut_max_ratio = parser_get_opt_param_float(
+        params, "Gravity:r_cut_max", gravity_props_default_r_cut_max);
+    p->r_cut_min_ratio = parser_get_opt_param_float(
+        params, "Gravity:r_cut_min", gravity_props_default_r_cut_min);
+
+    /* Some basic checks of what we read */
+    if (p->mesh_size % 2 != 0)
+      error("The mesh side-length must be an even number.");
+
+    if (p->a_smooth <= 0.)
+      error("The mesh smoothing scale 'a_smooth' must be > 0.");
+
+    if (2. * p->a_smooth * p->r_cut_max_ratio > p->mesh_size)
+      error("Mesh too small given r_cut_max. Should be at least %d cells wide.",
+            (int)(2. * p->a_smooth * p->r_cut_max_ratio) + 1);
+  } else {
+    p->mesh_size = 0;
+    p->a_smooth = 0.f;
+    p->r_cut_min_ratio = 0.f;
+    p->r_cut_max_ratio = 0.f;
+  }
 
   /* Time integration */
   p->eta = parser_get_param_float(params, "Gravity:eta");

src/gravity_properties.h

@@ -88,7 +88,8 @@ struct gravity_props {
 
 void gravity_props_print(const struct gravity_props *p);
 void gravity_props_init(struct gravity_props *p, struct swift_params *params,
-                        const struct cosmology *cosmo, int with_cosmology);
+                        const struct cosmology *cosmo, int with_cosmology,
+                        int periodic);
 void gravity_update(struct gravity_props *p, const struct cosmology *cosmo);
 
 #if defined(HAVE_HDF5)