pmgbergen/porepy: PorePy version 1.4.0

This release contains several updates to the code. The most important changes are:

• Substantial improvements to the meshing of fractured domains.
• Introduction of a new abstraction level for the automatic differentiation framework.
• The Biot class for poro-elasticity has clearly been defined as a backend class. To solve poro-elastic problems, use ContactMechanicsBiotModel instead.
• Support for Python 3.9 is introduced, support for 3.6 has been dropped.
• The stable branch has changed name from master to main.

Details:

• Meshing should be faster and more stable, in particular for geometries with many fractures. PorePy now uses the Gmsh python API directly. This can be used to modify mesh size parameters etc., although this has not been explored.
• The new Ad functionality is currently immature, and prone to sudden changes in the API. The hope is that this will become the new framework for defining equations (thus extending the Assembler, which is mainly targeted towards linear problems). The Ad functionality will be expanded over the coming months.

The following people have contributed to this release:

• Runar Lie Berge
• Jakub Both
• Alessio Fumagalli
• Eirik Keilegavlen
• Jhabriel Varela