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

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

Christian Engwer authored 5 years ago and Timo Koch committed 5 years ago

* update MatrixAdapter, OverlappingSchwarzOperator and NonoverlappingSchwarzOperator
* store matrix as `shared_ptr`
* update construction traits accordingly

Merge branch 'feature/deprecate-superlu-4' into 'master'

ref:core/dune-istl Removal of older SuperLU versions to reduce the number of
combinations to check. SuperLU 5.0 was released in July 2015. If we deprecate
SuperLU 4.x in Dune 2.7, it will be removed in 2020 with Dune 2.8.

See merge request [!285]

  [!285]: gitlab.dune-project.org/core/dune-istl/merge_requests/285

Merge branch 'feature/implement-scalarmatrixview' into 'master'

ref:core/dune-istl This is based on [dune-common!656] which introduces
Impl::asMatrix() using this we can avoid many Hybrid::ifElse constructions
which increase complexity of the implementation and error messages.
Furthermore we can drop toMatrix() which fixed [#63].

This is a clone of [!288]. Is was created in order to tell the CI to use the
corresponding branch in dune-common using a matching branch name.

See merge request [!289]

  [dune-common!656]: gitlab.dune-project.org/Nonedune-common/merge_requests/656
  [#63]: gitlab.dune-project.org/NoneNone/issues/63
  [!288]: gitlab.dune-project.org/NoneNone/merge_requests/288
  [!289]: gitlab.dune-project.org/core/dune-istl/merge_requests/289


Closes #63

Replace many `Hybrid::ifElse(IsNumber<...` constructions by
using `Impl::asMatrix()`. In some cases the (now only) implementation
of the matrix branch was additionally cleaned up using range-based
for.

Using `Impl::asMatrix()` we can replace many special case
implementations based on `Hybrid::ifElse(IsNumber...` which
simplifies code and error messages and avoids some code duplication.

This invokes undefined behaviour and was now replaced by asMatrix()
in dune-common.

The fundamental difference is, that `toMatrix()` leads to undefined
behaviour, because it dereference a pointer obtained from a
`reinterpret_cast` violating strict aliasing rules. In contrast
`asMatrix()` returns a wrapper modelling a proxy-matrix which
is safe to use.

Merge branch 'feature/simplify-scalar-entries' into 'master'

ref:core/dune-istl Using the new Impl::asVector() from dune-common we can get
rid of

-   several Hybrid::isElse() constructions used to implement special cases for
    isNumber,
-   undefined behaviour invoked by toVector() due to the latter violating
    strict aliasing rules.

This also removed the dangerous toVector() methods. This is only a partial
solution to [#63]. We also need to do the same for toMatrix() which requires
an analogue Impl::asMatrix() function and a ScalarMatrixView wrapper class.

See merge request [!287]

  [#63]: gitlab.dune-project.org/NoneNone/issues/63
  [!287]: gitlab.dune-project.org/core/dune-istl/merge_requests/287

Carsten Gräser authored 5 years ago and Oliver Sander committed 5 years ago

Using the wrapper generated by `asVector()` we can get rid of `toVector()`.
The important difference is, that `toVector()` invokes undefined behaviour
by dereferencing the result of an aliasing `reinterpret_cast`. However,
there's no noteable properties of the new implementation:
* You can't use `asVector()` directly in calls to `mv()` and friends,
  because the latter is not robust wrt. to proxy references.
* When creating copies of values, you can't replace
  `auto rhs = v[i];` by `auto rhs = Impl::asVector(v[i])`
  because proxy references don't use deep copy on purpose.
  Instead we have to use the two step
  `auto rhsValue = v[i]; auto&& rhs = Impl::asVector(rhsValue);`

Carsten Gräser authored 5 years ago and Oliver Sander committed 5 years ago

Using `Impl::asVector()` we can get rid of several `Hybrid::ifElse()`
constructions used to implement the special case of scalar entries
(i.e. `IsNumber==true`).

Merge branch 'fix_matrixredistribute_for_scalar_valued_matrices' into 'master'

ref:core/dune-istl This MR adapts matrixredistribute.hh for matrices with
scalar block_type like BCRSMatrix<double> and adapts the
matrixredistributetest.

See merge request [!278]

  [!278]: gitlab.dune-project.org/core/dune-istl/merge_requests/278

Merge branch 'improve-matrix-testing' into 'master'

See merge request [!282]

  [!282]: Nonecore/dune-istl/merge_requests/282

in order to get a `static constexpr` result, the method must be called via the type and not via `this`.