redesign-operator: MultiplyByElmtInvMass

Issue/feature addressed

The UnsteadyAdvection for DG requires a MultiplyByElmtInvMass operator. This branch implements a StdMat routine for the operator.

Proposed solution

This first attempt uses the legacy function calls creating a block matrix, that is saved in memory, and applying it to the input.

Implementation

This version handles vectorisation (including padding) by mapping from a Field container to a legacy-like array and applying the legacy routines for the BlockMatrix multiplication.

Tests

• The standard set of tests for all redesign operators.

Suggested reviewers

Notes

• The tricky part about this operator is that we would have to build and save the inverse mass matrix for each element. Is there a more efficient way of doing this operation?

Checklist

• Functions and classes, or changes to them, are documented.
• User guide/documentation is updated.
• Changelog is updated.
• Suitable tests added for new functionality.
• Contributed code is correctly formatted. (See the contributing guidelines).
• License added to any new files.
• No extraneous files have been added (e.g. compiler output or test data files).