Gmg preconditioner

[tjhei]

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[tjhei]

This only exists in solver.cc and won't be visible to GMG unless you move it to the header...

[tjhei]

maybe a first PR would only make this change and introduce the template arguments.

[tjhei]

also needs to be in the header

[tjhei]

the name StokesMatrixType is misleading. Shouldn't it be ABlockType, VelocityBlockType or AMatrixType or something?

[tjhei]

you will need to fix these comments

[tjhei]

Missing include:
�[K/home/runner/work/aspect/aspect/include/aspect/simulator/solver/block_stokes_preconditioner.h:118:19:�[m�[K �[Kerror: �[m�[K‘�[KSolverBicgstab�[m�[K’ was not declared in this scope

[tjhei]

you need to update test output:

diff --git a/tests/stokes_solver_fail/screen-output b/tests/stokes_solver_fail/screen-output
index 8a89c33..d672755 100644
--- a/tests/stokes_solver_fail/screen-output
+++ b/tests/stokes_solver_fail/screen-output
@@ -30,7 +30,9 @@ Additional information:
     void dealii::SolverFGMRES<VectorType>::solve(const MatrixType&,
     VectorType&, const VectorType&, const PreconditionerType&) [with
     MatrixType = aspect::internal::StokesBlock; PreconditionerType =
-    aspect::internal::BlockSchurPreconditioner<aspect::internal::InverseVelocityBlock<dealii::TrilinosWrappers::PreconditionAMG>,
+    aspect::internal::BlockSchurPreconditioner<aspect::internal::InverseVelocityBlock<dealii::TrilinosWrappers::PreconditionAMG,
+    dealii::TrilinosWrappers::MPI::Vector,
+    dealii::TrilinosWrappers::SparseMatrix>,
     aspect::internal::SchurComplementOperator,
     dealii::TrilinosWrappers::SparseMatrix,
     dealii::TrilinosWrappers::MPI::BlockVector>; VectorType =