Merge branch 'iterative_solver_cleanup' into 'master'

ref:core/dune-istl This MR removes duplicate code in iterative solvers by
moving

-   convergence check
-   invalid defect norm check (inf or NaN)
-   output

to a class Iteration. A instance of this class is created with
IterativeSolver::startIteration and is intended to be kept in the local scope
of the apply method. During iteration the method Iteration::step checks for
all the things mentioned above. The destructor fills all fields of
InverseOperatorResult and prints the final statistics if verbose is positive.

See merge request [!284]

  [!284]: gitlab.dune-project.org/core/dune-istl/merge_requests/284

Merge branch 'fix/ilu_documentation' into 'master'

ref:core/dune-istl The current documentation of SeqILU and SeqILUn claims,
that the parameter n is the number of iterations to perform. Actually the
parameter is passed into bilu_decomposition, which states that n is the order
of the ILU decomposition. This MR adjusts the docu on SeqILU and SeqILUn.

See merge request [!313]

  [!313]: gitlab.dune-project.org/core/dune-istl/merge_requests/313

# Conflicts:
#   dune/istl/solvers.hh

Merge branch 'add_constructors_that_take_shared_ptr_to_iterative_solvers' into 'master'

See merge request [!311]

  [!311]: Nonecore/dune-istl/merge_requests/311

Merge branch 'add_constructors_that_take_shared_ptr_to_iterative_solvers' into 'master'

ref:core/dune-istl This MR add constructors for IterativeSolvers that take
std::shared_ptr instead of references.

See merge request [!310]

  [!310]: gitlab.dune-project.org/core/dune-istl/merge_requests/310

Merge branch 'bugfix/colcomp-remove-warning' into 'master'

See merge request [!309]

  [!309]: Nonecore/dune-istl/merge_requests/309

Merge branch 'bug/document-scalarproduct-change' into 'master'

ref:core/dune-istl [!421] changed the signature of the methods dot() and
norm() in ScalarProduct, making them const. This breaks compilation of
existing user implementations, so let's document that change.

See merge request [!308]

  [!421]: gitlab.dune-project.org/NoneNone/merge_requests/421
  [!308]: gitlab.dune-project.org/core/dune-istl/merge_requests/308

!421 changed the signature of the methods `dot()` and `norm()` in
`ScalarProduct`, making them `const`. This breaks compilation of existing user
implementations, so let's document that change.

Merge branch 'unit-test-for-scalar-products' into 'master'

See merge request [!307]

  [!307]: Nonecore/dune-istl/merge_requests/307

Semantically they are const, and the current implementations
really are const too, so let's mark them in the interface
as such.

Merge branch 'issue/apply_forward' into 'master'

ref:core/dune-istl

### Summary

Implement apply<forward> for NonoverlappingBlockPreconditioner and replace
stored pointer with concrete type to allow the call to this non-virtual
function.

### Details

The method apply<forward>() is added for some preconditioners to allow to
distinguish between forward and backward application. This is not part of the
virtual interface in Preconditioner, so needs a concrete type to be called.
The function was missing in the NonoverlappingBlockPreconditioner that wraps
another preconditioner.

For both block preconditioners, the function apply<forward>() is called on the
abstract base class Preconditioner that does not have this method. So, instead
of storing a pointer to the base class, store the passed preconditioner type
directly that is available by template parameter.

### Backport

In dune 2.6 the base-class problem was not a problem, since there always the
template parameter type was stored. But the implementation in
NonoverlappingBlockPreconditioner is missing there as well. This simply breaks
generic code.

Note, the problem was introduced in [!274]. This MR is related to issue [#69].

See merge request [!302]

  [!274]: gitlab.dune-project.org/NoneNone/merge_requests/274
  [#69]: gitlab.dune-project.org/NoneNone/issues/69
  [!302]: gitlab.dune-project.org/core/dune-istl/merge_requests/302

Merge branch 'issue/missing_gs_construction_traits' into 'master'

ref:core/dune-istl

### Summary

This MR adds a missing specialization of the template ConstructionTraits for
the sequential preconditioner SeqGS.

See merge request [!303]

  [!303]: gitlab.dune-project.org/core/dune-istl/merge_requests/303

Merge branch 'feature/run-more-mpitests-in-parallel' into 'master'

See merge request [!296]

  [!296]: Nonecore/dune-istl/merge_requests/296

Merge branch 'feature/use-umfpack-dl-func-versions' into 'master'

See merge request [!301]

  [!301]: Nonecore/dune-istl/merge_requests/301

Kilian Weishaupt authored 5 years ago and Christoph Grüninger committed 5 years ago

With the *_dl_* versions instead of the *_di_* versions UMFPACK will
not have a memory limit of just 2GB.

Timo Koch authored 5 years ago and Christoph Grüninger committed 5 years ago

The index type was previously hard-coded to int. However, we might
want to change the index type for compatibility with legacy interfaces
of other libraries such as UMFPack.
This patch makes the index type customizable and defaults to int
for full backward-compatibility

Merge branch 'implement-bdmatrix-solve' into 'master'

ref:core/dune-istl This needs [!299].

See merge request [!300]

  [!299]: gitlab.dune-project.org/NoneNone/merge_requests/299
  [!300]: gitlab.dune-project.org/core/dune-istl/merge_requests/300

Merge branch 'bugfix/paamg-hierarchy-weak-ptr-may-be-nullptr' into 'master'

ref:core/dune-istl On the coarsest level, element_->coarser_ is empty and
constructing a shared_ptr from a weak_ptr fails. The lock() method returns an
empty shared_ptr instead.

This fails when iterating over the hierarchy as the end of the iteration
cannot be reached; the problem was previously described by @simon.praetorius
[1].

See merge request [!297]

  [1]: https://lists.dune-project.org/pipermail/dune-devel/2019-March/002441.html
  [!297]: gitlab.dune-project.org/core/dune-istl/merge_requests/297

Merge branch 'fix_checkIfDiagonalPresent_for_scalar_values_matrices' into 'master'

ref:core/dune-istl This MR fixes CheckIfDiagonalPresent for scalar matrices,
which is called by several preconditioners if dune-istl is compiled with
DUNE_ISTL_WITH_CHECKING.

See merge request [!298]

  [!298]: gitlab.dune-project.org/core/dune-istl/merge_requests/298

Merge branch 'fix/68-segfault-in-amg' into 'master'

ref:core/dune-istl Fixes [#68].

See merge request [!294]

  [#68]: gitlab.dune-project.org/NoneNone/issues/68
  [!294]: gitlab.dune-project.org/core/dune-istl/merge_requests/294


Closes #68

the vectors

On the coarsest level, `element_->coarser_` is empty and constructing
a `shared_ptr` from a `weak_ptr` fails.  The `lock()` method returns
an empty `shared_ptr` instead.

This fails when iterating over the hierarchy as the end of the
iteration cannot be reached; the problem was previously described by
@simon.praetorius [1].

  [1]: https://lists.dune-project.org/pipermail/dune-devel/2019-March/002441.html