Merge pull request #91 from StatikTUM/fix/solution-info

Fix solution info for arc-length

nfem/model.py

@@ -631,7 +631,7 @@ def perform_arc_length_control_step(self,
                                         = False
                                         ) -> None:
         """Perform a solution step using arc-length control."""
-        solution = self.solve_arc_length_control(tolerance, max_iterations)
+        solution_info = self.solve_arc_length_control(tolerance, max_iterations)
 
         if solve_det_k or solve_attendant_eigenvalue:
             assembler = Assembler(self)
@@ -647,9 +647,8 @@ def perform_arc_length_control_step(self,
             self.solve_eigenvalues(assembler=assembler)
 
         if info:
-            print('Arc-Length-Control with length = ' +
-                  f'{solution.constraint.squared_l_hat**0.5}')
-            solution.show()
+            print(solution_info.message)
+            solution_info.show()
             print()
 
     def solve_det_k(self) -> None:

nfem/solve.py

@@ -452,7 +452,10 @@ def compute_squared_arc_length(model):
 
     model.status = ModelStatus.equilibrium
 
-    return SolutionInfo(True, rnorm_history, dnorm_history)
+    solution_info = SolutionInfo(True, rnorm_history, dnorm_history)
+    solution_info.message = f'Arc-Length-Control with length = {squared_l_hat**0.5}'
+
+    return solution_info
 
 
 def _element_linear_r(element: Element):
@@ -474,6 +477,8 @@ def _element_k(element: Element):
 class SolutionInfo:
     """Container for linear solution info."""
 
+    message: str
+
     def __init__(self, converged: bool, rnorm: List[float], dnorm: List[float]):
         """Create a new linear SolutionInfo."""
         self.converged = converged