CHOLMOD supports this, it just wasn't exposed in the interface.
It is needed for large problems.

See https://reuse.software/ for a description.

This is achieved by using the flat matrix and vector forEach implementations.
The unit test is extended by a multi type example.

We interpret Cholmod as an InverseOperator between BlockVectors. Therefore
we dump the BCRSMatrix template.

To clarify the usage of ignore nodes the apply() method now ignores the corresponding entries directly.
The information is stored in a mapping from all indices to the not ignored indices.

Also, the unit tests for cholmod are extended.

Patrick Jaap authored 6 years ago and Christoph Grüninger committed 6 years ago

A simple implementation for the SuiteSparse CHOLMOD solver for real valued
(double) linear systems.
Ignore dof's are supported.
The user has to take care of the correct size of
vectors in the "apply" method.