[WIP] loosen nse constraint only after max subcycle is reached

Source/driver/Castro_advance_ctu.cpp

@@ -265,6 +265,13 @@ Castro::subcycle_advance_ctu(const Real time, const Real dt, int amr_iteration,
 
     Real last_dt_subcycle = 1.e200;
 
+#ifdef NSE_NET
+    bool do_loosen = true;
+    bool old_nse_dx_independent = nse_dx_independent;
+    bool old_nse_molar_independent = nse_molar_independent;
+    bool old_nse_skip_molar = nse_skip_molar;
+#endif
+
     while (subcycle_time < (1.0 - eps) * (time + dt)) {
 
         // Save the dt_subcycle before modifying it, we will use it later.
@@ -305,10 +312,31 @@ Castro::subcycle_advance_ctu(const Real time, const Real dt, int amr_iteration,
         int num_subcycles_remaining = int(round(((time + dt) - subcycle_time) / dt_subcycle));
 
         if (num_subcycles_remaining > max_subcycles) {
+#ifdef NSE_NET
+	  if (loosen_nse_bailout && do_loosen) {
+
+	    // find the smallest allowed dt_subcycle and then loosen nse_net bailout condition
+
+	    dt_subcycle = ((time + dt) - subcycle_time) / (max_subcycles);
+	    num_subcycles_remaining = max_subcycles;
+
+	    nse_dx_independent = true;
+	    nse_molar_independent = true;
+	    nse_skip_molar = true;
+	    do_loosen = false;
+
+	    amrex::Print() << std::endl
+			   << "  The subcycle mechanism requested " << num_subcycles_remaining << " subcycled timesteps, which is larger than the maximum of " << max_subcycles << "." << std::endl
+			   << "  Reperforming subcycle with smallest possible dt_subcycle and loosen nse bailout conditions." << std::endl;
+	  } else {
+#endif
             amrex::Print() << std::endl
                            << "  The subcycle mechanism requested " << num_subcycles_remaining << " subcycled timesteps, which is larger than the maximum of " << max_subcycles << "." << std::endl
                            << "  If you would like to override this, increase the parameter castro.max_subcycles." << std::endl;
             amrex::Abort("Error: too many subcycles.");
+#ifdef NSE_NET
+	  }
+#endif
         }
 
         // If we get to this point, we survived the sanity checks. Print out the current subcycle iteration.
@@ -492,6 +520,14 @@ Castro::subcycle_advance_ctu(const Real time, const Real dt, int amr_iteration,
 
     }
 
+#ifdef NSE_NET
+    // Restore the original nse configuration
+
+    nse_dx_independent = old_nse_dx_independent;
+    nse_molar_independent = old_nse_molar_independent;
+    nse_skip_molar = old_nse_skip_molar;
+#endif
+
     // We want to return the subcycled timestep as a suggestion.
     // Let's be sure to return the subcycled timestep that was
     // unmodified by anything we had to do in the last subcycle

Source/driver/_cpp_parameters

@@ -371,6 +371,9 @@ stopping_criterion_field     string        ""
 # Threshold value for determining whether to stop.
 stopping_criterion_value     Real          1.e200
 
+# whether to loosen nse bailout condition when max_subcycles is reached
+loosen_nse_bailout               int           0
+
 #-----------------------------------------------------------------------------
 # category: reactions
 #-----------------------------------------------------------------------------