[Fem] Elmer: update tolerances

- update tolerances also for existing analyses to fix the bug that users see e.g. "0.001" and not the actual used tolerance
- also a fix for new stress analyses
- also a formatting fix

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

@@ -235,7 +235,9 @@ class Proxy(linear.Proxy, equationbase.ElasticityProxy):
         obj.EigenSystemSelect = "Smallest Magnitude"
         # according to Elmer manual default is 100 times the Linear Tolerance
         # since this is a small value we must set an expression, see linear.py for background
-        obj.setExpression("EigenSystemTolerance", str(100 * obj.LinearTolerance))
+        for (prop, expr) in obj.ExpressionEngine:
+            if (prop == "LinearTolerance"):
+                obj.setExpression("EigenSystemTolerance", str(100 * obj.evalExpression(expr)))
         obj.Variable = "Displacement"
 
 

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

@@ -110,7 +110,7 @@ class Proxy(equation.Proxy):
         # view and edit the tolerance via the property editor and this does not
         # yet allow to view and edit small numbers in scientific notation
         # forum thread: https://forum.freecadweb.org/viewtopic.php?p=613897#p613897
-        obj.setExpression('LinearTolerance', "1e-8")
+        obj.setExpression("LinearTolerance", "1e-8")
         obj.addProperty(
             "App::PropertyInteger",
             "LinearIterations",
@@ -125,7 +125,7 @@ class Proxy(equation.Proxy):
             ""
         )
         # same as with LinearTolerance
-        obj.setExpression('SteadyStateTolerance', "1e-5")
+        obj.setExpression("SteadyStateTolerance", "1e-5")
 
         obj.addProperty(
             "App::PropertyBool",

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

@@ -76,9 +76,9 @@ class Proxy(linear.Proxy):
         # the user has to view and edit the tolerance via the property editor and
         # this does not yet allow to view and edit small numbers in scientific notation
         # forum thread: https://forum.freecadweb.org/viewtopic.php?p=613897#p613897
-        obj.setExpression('NonlinearTolerance', "1e-8")
-        obj.setExpression('NonlinearNewtonAfterTolerance', "1e-3")
-        obj.setExpression('RelaxationFactor', "1.0")  # must often be < 1 down to 0.01
+        obj.setExpression("NonlinearTolerance", "1e-8")
+        obj.setExpression("NonlinearNewtonAfterTolerance", "1e-3")
+        obj.setExpression("RelaxationFactor", "1.0")  # must often be < 1 down to 0.01
 
 
 class ViewProxy(linear.ViewProxy):

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

@@ -1223,7 +1223,24 @@ class Writer(object):
         s = sifio.createSection(sifio.SOLVER)
         return s
 
+    def _hasExpression(self, equation):
+        obj = None
+        exp = None
+        for (obj, exp) in equation.ExpressionEngine:
+            if obj == equation:
+                return exp
+        return None
+
+    def _updateLinearSolver(self, equation):
+        if self._hasExpression(equation) != equation.LinearTolerance:
+            equation.setExpression("LinearTolerance", str(equation.LinearTolerance))
+        if self._hasExpression(equation) != equation.SteadyStateTolerance:
+            equation.setExpression("SteadyStateTolerance", str(equation.SteadyStateTolerance))
+
     def _createLinearSolver(self, equation):
+        # first check if we have to update
+        self._updateLinearSolver(equation)
+        # write the solver
         s = sifio.createSection(sifio.SOLVER)
         s.priority = equation.Priority
         s["Linear System Solver"] = equation.LinearSolverType
@@ -1249,8 +1266,19 @@ class Writer(object):
         s["Linear System Precondition Recompute"] = 1
         return s
 
+    def _updateNonlinearSolver(self, equation):
+        if self._hasExpression(equation) != equation.NonlinearTolerance:
+            equation.setExpression("NonlinearTolerance", str(equation.NonlinearTolerance))
+        if self._hasExpression(equation) != equation.NonlinearNewtonAfterTolerance:
+            equation.setExpression("NonlinearNewtonAfterTolerance",\
+                str(equation.NonlinearNewtonAfterTolerance))
+
     def _createNonlinearSolver(self, equation):
+        # first check if we have to update
+        self._updateNonlinearSolver(equation)
+        # write the linear solver
         s = self._createLinearSolver(equation)
+        # write the nonlinear solver
         s["Nonlinear System Max Iterations"] = \
             equation.NonlinearIterations
         s["Nonlinear System Convergence Tolerance"] = \