diff --git a/GUI/Model/ToCore/SimulationToCore.cpp b/GUI/Model/ToCore/SimulationToCore.cpp
index 854a878d71ba806fa264870a839f7ecb33a2c72e..0342514c85f48c90e78724fe06b16346c9660383 100644
--- a/GUI/Model/ToCore/SimulationToCore.cpp
+++ b/GUI/Model/ToCore/SimulationToCore.cpp
@@ -22,9 +22,7 @@
 #include "Sample/Multilayer/MultiLayer.h"
 #include "Sim/Simulation/ISimulation.h"
 
-namespace {
-
-void setSimulationOptions(ISimulation* simulation, const SimulationOptionsItem& item)
+void GUI::ToCore::setSimulationOptions(ISimulation* simulation, const SimulationOptionsItem& item)
 {
     simulation->options().setNumberOfThreads(item.numberOfThreads());
     if (item.useMonteCarloIntegration())
@@ -33,9 +31,6 @@ void setSimulationOptions(ISimulation* simulation, const SimulationOptionsItem&
     simulation->options().setIncludeSpecular(item.includeSpecularPeak());
 }
 
-} // namespace
-
-
 std::unique_ptr<ISimulation>
 GUI::ToCore::itemsToSimulation(const SampleItem& sampleItem, const InstrumentItem& instrumentItem,
                                const SimulationOptionsItem& optionsItem)
diff --git a/GUI/Model/ToCore/SimulationToCore.h b/GUI/Model/ToCore/SimulationToCore.h
index 1d188ba007fbac8311e5bbc551d6a1532413527a..3fc54621dc67681990da17d241b1c97a72265811 100644
--- a/GUI/Model/ToCore/SimulationToCore.h
+++ b/GUI/Model/ToCore/SimulationToCore.h
@@ -27,11 +27,12 @@ class SimulationOptionsItem;
 namespace GUI::ToCore {
 
 //! Creates domain simulation from sample and instrument items.
-
 std::unique_ptr<ISimulation> itemsToSimulation(const SampleItem& sampleItem,
                                                const InstrumentItem& instrumentItem,
                                                const SimulationOptionsItem& optionsItem);
 
+void setSimulationOptions(ISimulation* simulation, const SimulationOptionsItem& item);
+
 } // namespace GUI::ToCore
 
 #endif // BORNAGAIN_GUI_MODEL_TOCORE_SIMULATIONTOCORE_H