From 848a1818ff7042f58023611309ac5c8bae1b5c8f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20Simonis?= <simonisfrederic@gmail.com>
Date: Mon, 29 Jan 2024 15:41:20 +0100
Subject: [PATCH] Fix tolerance check for subcycling

---
 Adapter.C | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/Adapter.C b/Adapter.C
index 74b63783..38c061ab 100644
--- a/Adapter.C
+++ b/Adapter.C
@@ -652,7 +652,13 @@ void preciceAdapter::Adapter::adjustSolverTimeStepAndReadData()
        the same timestep as the one determined by preCICE.
     */
     double tolerance = 1e-14;
-    if (timestepPrecice_ - timestepSolverDetermined > tolerance)
+    if (abs(timestepPrecice_ - timestepSolverDetermined) < tolerance)
+    {
+        DEBUG(adapterInfo("The solver's timestep is the same as the "
+                          "coupling timestep."));
+        timestepSolver_ = timestepPrecice_;
+    }
+    else if (timestepPrecice_ - timestepSolverDetermined > tolerance)
     {
         // Add a bool 'subCycling = true' which is checked in the storeMeshPoints() function.
         adapterInfo(
@@ -668,7 +674,7 @@ void preciceAdapter::Adapter::adjustSolverTimeStepAndReadData()
                 "warning");
         }
     }
-    else if (timestepSolverDetermined - timestepPrecice_ > tolerance)
+    else 
     {
         // In the last time-step, we adjust to dt = 0, but we don't need to trigger the warning here
         if (precice_->isCouplingOngoing())
@@ -681,12 +687,6 @@ void preciceAdapter::Adapter::adjustSolverTimeStepAndReadData()
         }
         timestepSolver_ = timestepPrecice_;
     }
-    else
-    {
-        DEBUG(adapterInfo("The solver's timestep is the same as the "
-                          "coupling timestep."));
-        timestepSolver_ = timestepPrecice_;
-    }
 
     // Update the solver's timestep (but don't trigger the adjustDeltaT(),
     // which also triggers the functionObject's adjustTimeStep())