Add a function to set the cosmological factors to valid values when running a...

Add a function to set the cosmological factors to valid values when running a non-cosmological case.

examples/main.c

@@ -601,7 +601,10 @@ int main(int argc, char *argv[]) {
 
     /* Initialise the cosmology */
     struct cosmology cosmo;
-    if (with_cosmology) cosmology_init(params, &us, &prog_const, &cosmo);
+    if (with_cosmology)
+      cosmology_init(params, &us, &prog_const, &cosmo);
+    else
+      cosmology_init_no_cosmo(params, &us, &prog_const, &cosmo);
     if (with_cosmology) cosmology_print(&cosmo);
 
     /* Initialise the hydro properties */

src/cosmology.c

@@ -421,6 +421,51 @@ void cosmology_init(const struct swift_params *params,
   cosmology_init_tables(c);
 }
 
+/**
+ * @brief Initialise the #cosmology for non-cosmological time-integration
+ *
+ * Essentially sets all constants to 1.
+ *
+ * @param params The parsed values.
+ * @param us The current internal system of units.
+ * @param phys_const The physical constants in the current system of units.
+ * @param c The #cosmology to initialise.
+ */
+void cosmology_init_no_cosmo(const struct swift_params *params,
+                             const struct unit_system *us,
+                             const struct phys_const *phys_const,
+                             struct cosmology *c) {
+
+  c->Omega_m = 0.;
+  c->Omega_r = 0.;
+  c->Omega_k = 0.;
+  c->Omega_lambda = 0.;
+  c->Omega_b = 0.;
+  c->w_0 = 0.;
+  c->w_a = 0.;
+  c->h = 0.;
+  c->w = 0.;
+
+  c->a_begin = 1.;
+  c->a_end = 1.;
+  c->log_a_begin = 0.;
+  c->log_a_end = 0.;
+
+  c->H = 1.;
+  c->a = 1.;
+  c->a_inv = 1.;
+  c->a_dot = 0.;
+  c->time = 0.;
+  c->universe_age_at_present_day = 0.;
+
+  /* Initialise the interpolation tables */
+  c->drift_fac_interp_table = NULL;
+  c->grav_kick_fac_interp_table = NULL;
+  c->hydro_kick_fac_interp_table = NULL;
+  c->time_interp_table = NULL;
+  c->time_interp_table_offset = 0.;
+}
+
 /**
  * @brief Computes the cosmology factor that enters the drift operator.
  *

src/cosmology.h

@@ -146,6 +146,11 @@ void cosmology_init(const struct swift_params *params,
                     const struct unit_system *us,
                     const struct phys_const *phys_const, struct cosmology *c);
 
+void cosmology_init_no_cosmo(const struct swift_params *params,
+                             const struct unit_system *us,
+                             const struct phys_const *phys_const,
+                             struct cosmology *c);
+
 void cosmology_print(const struct cosmology *c);
 void cosmology_clean(struct cosmology *c);