From 0675b8471dd1611d4d50884a6fc02e127e61f3d1 Mon Sep 17 00:00:00 2001
From: Andreas <38031952+AnHeuermann@users.noreply.github.com>
Date: Wed, 22 Nov 2023 10:05:24 +0100
Subject: [PATCH] [C Runtime] Check DASSL step size (#11617)

- Compared step size to order of magnitude of simulation duration
---
 OMCompiler/SimulationRuntime/c/simulation/solver/dassl.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/OMCompiler/SimulationRuntime/c/simulation/solver/dassl.c b/OMCompiler/SimulationRuntime/c/simulation/solver/dassl.c
index 40edb077a94..103bb0fdf6f 100644
--- a/OMCompiler/SimulationRuntime/c/simulation/solver/dassl.c
+++ b/OMCompiler/SimulationRuntime/c/simulation/solver/dassl.c
@@ -600,10 +600,12 @@ int dassl_step(DATA* data, threadData_t *threadData, SOLVER_INFO* solverInfo)
   }
 
   /* Check that tout is not less than timeValue
-   * else will dassl get in trouble. If that is the case we skip the current step. */
-  if (solverInfo->currentStepSize < DASSL_STEP_EPS)
+   * else will dassl get in trouble. If that is the case we skip the current step.
+     Also check if step size is smaller than DASSL_STEP_EPS or DASSL_STEP_EPS times simulation interval */
+  if ((solverInfo->currentStepSize < DASSL_STEP_EPS) ||
+      (solverInfo->currentStepSize < DASSL_STEP_EPS*(data->simulationInfo->stopTime - data->simulationInfo->startTime)) )
   {
-    infoStreamPrint(LOG_DASSL, 0, "Desired step to small try next one");
+    infoStreamPrint(LOG_DASSL, 0, "Desired step size %e to small.", solverInfo->currentStepSize);
     infoStreamPrint(LOG_DASSL, 0, "Interpolate linear");
 
     /*euler step*/