update output for petsc_complex/solver_real_01/02

diff --git a/tests/petsc_complex/solver_real_01.output b/tests/petsc_complex/solver_real_01.output
index 94aba8fe1f76d1169bb8822fd5b4b4bdcd4c4981..79c6bb04096d45e2c56a338858c7d5573a96d666 100644 (file)
--- a/tests/petsc_complex/solver_real_01.output
+++ b/tests/petsc_complex/solver_real_01.output
@@ -6,13 +6,17 @@ DEAL::Failure step 100 value 4.004
 DEAL::
 --------------------------------------------------------
 An error occurred in file <petsc_solver.cc> in function
-    void dealii::PETScWrappers::SolverBase::solve(const dealii::PETScWrappers::MatrixBase&, dealii::PETScWrappers::VectorBase&, const dealii::PETScWrappers::VectorBase&, const dealii::PETScWrappers::PreconditionerBase&)
+    void dealii::PETScWrappers::SolverBase::solve(const dealii::PETScWrappers::MatrixBase &, dealii::PETScWrappers::VectorBase &, const dealii::PETScWrappers::VectorBase &, const dealii::PETScWrappers::PreconditionerBase &)
 The violated condition was: 
     false
 The name and call sequence of the exception was:
     SolverControl::NoConvergence (solver_control.last_step(), solver_control.last_value())
 Additional Information: 
-Iterative method reported convergence failure in step 100 with residual 4.00437
+Iterative method reported convergence failure in step 100. The residual in the last step was 4.00437.
+
+This error message can indicate that you have simply not allowed a sufficiently large number of iterations for your iterative solver to converge. This often happens when you increase the size of your problem. In such cases, the last residual will likely still be very small, and you can make the error go away by increasing the allowed number of iterations when setting up the SolverControl object that determines the maximal number of iterations you allow.
+
+The other situation where this error may occur is when your matrix is not invertible (e.g., your matrix has a null-space), or if you try to apply the wrong solver to a matrix (e.g., using CG for a matrix that is not symmetric or not positive definite). In these cases, the residual in the last iteration is likely going to be large.
 --------------------------------------------------------
 
 DEAL::Solver stopped after 100 iterations

diff --git a/tests/petsc_complex/solver_real_02.output b/tests/petsc_complex/solver_real_02.output
index de02386e0c8fb19de8a983e91e9c657a140a5256..0dc47c2a6c846f65618392ea523eb409ae73efcb 100644 (file)
--- a/tests/petsc_complex/solver_real_02.output
+++ b/tests/petsc_complex/solver_real_02.output
@@ -2,17 +2,21 @@
 DEAL::Size 32 Unknowns 961
 DEAL::Solver type: N6dealii13PETScWrappers15SolverChebychevE
 DEAL::Starting value 7.551
-DEAL::Failure step 100 value 2.942
+DEAL::Failure step 100 value 2.937
 DEAL::
 --------------------------------------------------------
 An error occurred in file <petsc_solver.cc> in function
-    void dealii::PETScWrappers::SolverBase::solve(const dealii::PETScWrappers::MatrixBase&, dealii::PETScWrappers::VectorBase&, const dealii::PETScWrappers::VectorBase&, const dealii::PETScWrappers::PreconditionerBase&)
+    void dealii::PETScWrappers::SolverBase::solve(const dealii::PETScWrappers::MatrixBase &, dealii::PETScWrappers::VectorBase &, const dealii::PETScWrappers::VectorBase &, const dealii::PETScWrappers::PreconditionerBase &)
 The violated condition was: 
     false
 The name and call sequence of the exception was:
     SolverControl::NoConvergence (solver_control.last_step(), solver_control.last_value())
 Additional Information: 
-Iterative method reported convergence failure in step 100 with residual 2.94179
+Iterative method reported convergence failure in step 100. The residual in the last step was 2.9372.
+
+This error message can indicate that you have simply not allowed a sufficiently large number of iterations for your iterative solver to converge. This often happens when you increase the size of your problem. In such cases, the last residual will likely still be very small, and you can make the error go away by increasing the allowed number of iterations when setting up the SolverControl object that determines the maximal number of iterations you allow.
+
+The other situation where this error may occur is when your matrix is not invertible (e.g., your matrix has a null-space), or if you try to apply the wrong solver to a matrix (e.g., using CG for a matrix that is not symmetric or not positive definite). In these cases, the residual in the last iteration is likely going to be large.
 --------------------------------------------------------
 
 DEAL::Solver stopped after 100 iterations