Add over relaxation parameter

examples/parameter_example.yml

@@ -189,6 +189,9 @@ GrackleCooling:
   ProvideSpecificHeatingRates: 0 # User provide specific heating rates
   SelfShieldingMethod: 0 # Grackle (<= 3) or Gear self shielding method
   OutputMode: 0 # Write in output corresponding primordial chemistry mode
+  MaxSteps: 10000 # (optional) Max number of step when computing the initial composition
+  ConvergenceLimit: 1e-2 # (optional) Convergence threshold (relative) for initial composition
+  Omega: 0.8 # (optional) Over relaxation coefficient for initial composition (< 1 avoid oscillation, > 1 speedup convergence)
 
 # Parameters related to chemistry models  -----------------------------------------------
 

src/cooling/grackle/cooling.h

@@ -202,7 +202,6 @@ __attribute__((always_inline)) INLINE static void cooling_compute_equilibrium_fr
   /* a few constants */
   const float limit = tmp_cooling.convergence_limit;
   const double dt = 0.01 * fabs(cooling_time(&tmp_cooling, p, xp));
-  const float omega = 0.8;
   
   /* disable energy updates */
   tmp_cooling.chemistry.with_radiative_cooling = 0;
@@ -216,7 +215,7 @@ __attribute__((always_inline)) INLINE static void cooling_compute_equilibrium_fr
     /* compute cooling rate */
     cooling_rate(NULL, NULL, &tmp_cooling, p, xp, dt);
 
-    cooling_over_relaxation(xp, &xp_1, omega);
+    cooling_over_relaxation(xp, &xp_1, cooling->omega);
 
   } while(!cooling_check_convergence(&xp_1, xp, limit) &&
 	  step < tmp_cooling.max_step);

src/cooling/grackle/cooling_io.h

@@ -154,6 +154,9 @@ __attribute__((always_inline)) INLINE static void cooling_parse_arguments(
 
   cooling->convergence_limit =
     parser_get_opt_param_double(parameter_file, "GrackleCooling:ConvergenceLimit", 1e-2);
+
+  cooling->convergence_limit =
+    parser_get_opt_param_double(parameter_file, "GrackleCooling:Omega", 0.8);
 }
 
 

src/cooling/grackle/cooling_struct.h

@@ -69,6 +69,9 @@ struct cooling_function_data {
 
   /* number of step max for first init */
   int max_step;
+
+  /* over relaxation parameter */
+  float omega;
 };
 
 /**