Fix roundoff issue in SUNDIALS evolve() (#4148)

Fix a roundoff issue in the SUNDIALS evolve() function that caused the integrator to run a second time with a very tiny dt in a given time step.
AMReX-Codes · Sep 17, 2024 · 73716d9 · 73716d9
1 parent eecb9ea
commit 73716d9
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/Src/Base/AMReX_RKIntegrator.H b/Src/Base/AMReX_RKIntegrator.H
@@ -251,7 +251,8 @@ public:
         for (int step_number = 0; step_number < BaseT::max_steps && !stop; ++step_number)
         {
             // Adjust step size to reach output time
-            if (time_out - time_current < dt) {
+            // protect against roundoff
+            if ((time_out-time_current) < dt || almostEqual(time_out-time_current,dt,10)) {
                 dt = time_out - time_current;
                 stop = true;
             }