[FEM] Elmer: fixes for the simulation parameters

- output equation-specific values only if this equation is used
- use Elmer's default for BDF order as default for FC too and allow to change it
- don't hardcode to Steady State. Transient must be possible too, this way add parameters to run a transient analysis

src/Mod/Fem/femsolver/elmer/equations/heat.py

@@ -53,9 +53,9 @@ class Proxy(nonlinear.Proxy, equationbase.HeatProxy):
             "Heat",
             ""
         )
+        
         obj.Bubbles = True
         obj.Stabilize = False
-
         obj.Priority = 20
 
 

src/Mod/Fem/femsolver/elmer/solver.py

@@ -47,6 +47,7 @@ from femtools import femutils
 if FreeCAD.GuiUp:
     import FemGui
 
+SIMULATION_TYPE = ["Scanning", "Steady State", "Transient"]
 
 def create(doc, name="ElmerSolver"):
     return femutils.createObject(
@@ -70,19 +71,60 @@ class Proxy(solverbase.Proxy):
     def __init__(self, obj):
         super(Proxy, self).__init__(obj)
 
+        obj.addProperty(
+            "App::PropertyIntegerConstraint",
+            "BDFOrder",
+            "Timestepping",
+            "Order of time stepping method 'BDF'"
+        )
+        # according to the Elmer manual recommended is order 2
+        # possible ranage is 1 - 5
+        obj.BDFOrder = (2, 1, 5, 1)
+
+        obj.addProperty(
+            "App::PropertyIntegerConstraint",
+            "TimestepIntervals",
+            "Timestepping",
+            "Maximum optimization rounds if 'Simulation Type'\nis either 'Scanning' or 'Transient'"
+        )
+        obj.addProperty(
+            "App::PropertyFloatConstraint",
+            "TimestepSizes",
+            "Timestepping",
+            "Time step of optimization if 'Simulation Type'\nis either 'Scanning' or 'Transient'"
+        )
+        # there is no universal default, it all depends on the analysis, however
+        # we have to set something and set 10 seconds in steps of 0.1s
+        # since the Emler manual lacks proper info, here a link to a forum thread:
+        # http://www.elmerfem.org/forum/viewtopic.php?p=18057&sid=73169c4ec544fd7f181f85178bbc8ffe#p18057
+        # -----
+        # Set maximum to 1e8 because on Win the max int is always 32bit (4.29e9)
+        # for TimestepSizes also 1e8 just to set something
+        obj.TimestepIntervals = (100, 1, int(1e8), 10)
+        obj.TimestepSizes = (0.1, 1e-8, 1e8, 0.1)
+
+        obj.addProperty(
+            "App::PropertyEnumeration",
+            "SimulationType",
+            "Type",
+            ""
+        )
+        obj.SimulationType = SIMULATION_TYPE
+        obj.SimulationType = "Steady State"
+
         obj.addProperty(
             "App::PropertyInteger",
             "SteadyStateMaxIterations",
-            "Steady State",
-            ""
+            "Type",
+            "Maximal steady state iterations"
         )
         obj.SteadyStateMaxIterations = 1
 
         obj.addProperty(
             "App::PropertyInteger",
             "SteadyStateMinIterations",
-            "Steady State",
-            ""
+            "Type",
+            "Minimal steady state iterations"
         )
         obj.SteadyStateMinIterations = 0
 

src/Mod/Fem/femsolver/elmer/writer.py

@@ -309,23 +309,72 @@ class Writer(object):
             )
 
     def _handleSimulation(self):
+        # check if we need to update the equation
+        self._updateSimulation(self.solver)
+        # output the equation parameters
+        # first check what equations we have
+        hasHeat = False
+        for equation in self.solver.Group:
+            if femutils.is_of_type(equation, "Fem::EquationElmerHeat"):
+                hasHeat = True
+        if hasHeat:
+           self._simulation("BDF Order", self.solver.BDFOrder)
         self._simulation("Coordinate System", "Cartesian 3D")
         self._simulation("Coordinate Mapping", (1, 2, 3))
         # Elmer uses SI base units, but our mesh is in mm, therefore we must tell
         # the solver that we have another scale
         self._simulation("Coordinate Scaling", 0.001)
-        self._simulation("Simulation Type", "Steady state")
-        self._simulation("Steady State Max Iterations", 1)
         self._simulation("Output Intervals", 1)
-        self._simulation("Timestepping Method", "BDF")
-        self._simulation("BDF Order", 1)
+        self._simulation("Simulation Type",
+            self.solver.SimulationType)
+        if self.solver.SimulationType == "Steady State":
+            self._simulation(
+                "Steady State Max Iterations", self.solver.SteadyStateMaxIterations)
+            self._simulation(
+                "Steady State Min Iterations", self.solver.SteadyStateMinIterations)
+        if (self.solver.SimulationType == "Scanning") \
+          or (self.solver.SimulationType == "Transient"):
+            self._simulation("Timestep Intervals", self.solver.TimestepIntervals)
+            self._simulation("Timestep Sizes", self.solver.TimestepSizes)
+        if hasHeat:
+            self._simulation("Timestepping Method", "BDF")
         self._simulation("Use Mesh Names", True)
-        self._simulation(
-            "Steady State Max Iterations",
-            self.solver.SteadyStateMaxIterations)
-        self._simulation(
-            "Steady State Min Iterations",
-            self.solver.SteadyStateMinIterations)
+    
+    def _updateSimulation(self, solver):
+        # updates older simulations
+        if not hasattr(self.solver, "BDFOrder"):
+            solver.addProperty(
+            "App::PropertyIntegerConstraint",
+            "BDFOrder",
+            "Timestepping",
+            "Order of time stepping method 'BDF'"
+            )
+            solver.BDFOrder = (2, 1, 5, 1)
+        if not hasattr(self.solver, "SimulationType"):
+            solver.addProperty(
+            "App::PropertyEnumeration",
+            "SimulationType",
+            "Type",
+            ""
+            )
+            solver.SimulationType = ["Scanning", "Steady State", "Transient"]
+            solver.SimulationType = "Steady State"
+        if not hasattr(self.solver, "TimestepIntervals"):
+            solver.addProperty(
+            "App::PropertyIntegerConstraint",
+            "TimestepIntervals",
+            "Timestepping",
+            "Maximum optimization rounds if 'Simulation Type'\nis either 'Scanning' or 'Transient'"
+            )
+            solver.TimestepIntervals = (100, 1, int(1e8), 10)
+        if not hasattr(self.solver, "TimestepSizes"):
+            solver.addProperty(
+            "App::PropertyFloatConstraint",
+            "TimestepSizes",
+            "Timestepping",
+            "Time step of optimization if 'Simulation Type'\nis either 'Scanning' or 'Transient'"
+            )
+            solver.TimestepSizes = (0.1, 1e-8, 1e8, 0.1)
 
     def _handleHeat(self):
         activeIn = []

src/Mod/Fem/femtest/data/elmer/box_static_0_mm.sif

@@ -24,15 +24,13 @@ Solver 1
 End
 
 Simulation 
-  BDF Order = Integer 1
   Coordinate Mapping(3) = Integer 1 2 3
   Coordinate Scaling = Real 0.001
   Coordinate System = String "Cartesian 3D"
   Output Intervals = Integer 1
-  Simulation Type = String "Steady state"
+  Simulation Type = String "Steady State"
   Steady State Max Iterations = Integer 1
   Steady State Min Iterations = Integer 0
-  Timestepping Method = String "BDF"
   Use Mesh Names = Logical True
 End
 

src/Mod/Fem/femtest/data/elmer/ccxcantilever_faceload_0_mm.sif

@@ -24,15 +24,13 @@ Solver 1
 End
 
 Simulation 
-  BDF Order = Integer 1
   Coordinate Mapping(3) = Integer 1 2 3
   Coordinate Scaling = Real 0.001
   Coordinate System = String "Cartesian 3D"
   Output Intervals = Integer 1
-  Simulation Type = String "Steady state"
+  Simulation Type = String "Steady State"
   Steady State Max Iterations = Integer 1
   Steady State Min Iterations = Integer 0
-  Timestepping Method = String "BDF"
   Use Mesh Names = Logical True
 End
 

src/Mod/Fem/femtest/data/elmer/ccxcantilever_faceload_1_si.sif

@@ -24,15 +24,13 @@ Solver 1
 End
 
 Simulation 
-  BDF Order = Integer 1
   Coordinate Mapping(3) = Integer 1 2 3
   Coordinate Scaling = Real 0.001
   Coordinate System = String "Cartesian 3D"
   Output Intervals = Integer 1
-  Simulation Type = String "Steady state"
+  Simulation Type = String "Steady State"
   Steady State Max Iterations = Integer 1
   Steady State Min Iterations = Integer 0
-  Timestepping Method = String "BDF"
   Use Mesh Names = Logical True
 End
 

src/Mod/Fem/femtest/data/elmer/ccxcantilever_nodeload_0_mm.sif

@@ -24,15 +24,13 @@ Solver 1
 End
 
 Simulation 
-  BDF Order = Integer 1
   Coordinate Mapping(3) = Integer 1 2 3
   Coordinate Scaling = Real 0.001
   Coordinate System = String "Cartesian 3D"
   Output Intervals = Integer 1
-  Simulation Type = String "Steady state"
+  Simulation Type = String "Steady State"
   Steady State Max Iterations = Integer 1
   Steady State Min Iterations = Integer 0
-  Timestepping Method = String "BDF"
   Use Mesh Names = Logical True
 End
 

src/Mod/Fem/femtest/data/elmer/ccxcantilever_prescribeddisplacement_0_mm.sif

@@ -24,15 +24,13 @@ Solver 1
 End
 
 Simulation 
-  BDF Order = Integer 1
   Coordinate Mapping(3) = Integer 1 2 3
   Coordinate Scaling = Real 0.001
   Coordinate System = String "Cartesian 3D"
   Output Intervals = Integer 1
-  Simulation Type = String "Steady state"
+  Simulation Type = String "Steady State"
   Steady State Max Iterations = Integer 1
   Steady State Min Iterations = Integer 0
-  Timestepping Method = String "BDF"
   Use Mesh Names = Logical True
 End