[FEM] fix broken Z88 part 1: don't hardcode solver

- especially don't hardcode the choly solver that fails quickly for finer meshes
- setting sorcg as default since it shows the best performance with the cantilever tests

src/Mod/Fem/femsolver/z88/tasks.py

@@ -42,6 +42,7 @@ from femmesh import meshsetsgetter
 from femtools import femutils
 from femtools import membertools
 
+SOLVER_TYPES = ["sorcg", "siccg", "choly"]
 
 class Check(run.Check):
 
@@ -102,6 +103,12 @@ class Solve(run.Solve):
         binary = settings.get_binary("Z88")
         if binary is None:
             self.fail()  # a print has been made in settings module
+        
+        prefs = FreeCAD.ParamGet("User parameter:BaseApp/Preferences/Mod/Fem/Z88")
+        solver = SOLVER_TYPES
+        solver = prefs.GetInt("Solver", 0)
+        solver = SOLVER_TYPES[solver]
+        self.pushStatus("used solver: " + solver + "\n")
 
         # run solver test mode
         # AFAIK: z88r needs to be run twice
@@ -111,7 +118,7 @@ class Solve(run.Solve):
         # may be compare with the used ones
         self.pushStatus("Executing solver in test mode...\n")
         self._process = subprocess.Popen(
-            [binary, "-t", "-choly"],
+            [binary, "-t", "-" + solver],
             cwd=self.directory,
             stdout=subprocess.PIPE,
             stderr=subprocess.PIPE)
@@ -123,7 +130,7 @@ class Solve(run.Solve):
         self.pushStatus("Executing solver in real mode...\n")
         binary = settings.get_binary("Z88")
         self._process = subprocess.Popen(
-            [binary, "-c", "-choly"],
+            [binary, "-c", "-" + solver],
             cwd=self.directory,
             stdout=subprocess.PIPE,
             stderr=subprocess.PIPE)