Better 2D Curvilinear Operators (MATLAB)

[bewagner1]

What type of PR is this? (check all applicable)

• Refactor
• Feature
• Bug Fix
• Optimization
• Example
• Documentation

Description

The current curvilinear operators have some issues.

• They use MATLAB interpolators, which are only 2nd order.
• They cannot handle periodic domains
• Their implementation does not follow what is outlined in the documentation very closely (nodal Jacobian)
• Their implementation is hard to follow (DI2 and GI2 functions)
• Their accuracy doesn't really change with k and don't have _k_th order accuracy

This new implementation alleviates those issues, but still raises some of its own. These operators output to or act on the "extended" faces. These are the normal faces, plus the boundaries (see below).

Related Issues & Documents

• I have created an Issue that is paired with this PR

QA Instructions, Screenshots, Recordings

Run the file curvConvergenceTest.m in examples/matlab_octave.

Added/updated tests?

• Yes
• No, and this is why: please replace this line with details on why tests
  have not been included
• I need help with writing tests

Read Contributing Guide and Code of Conduct

• 📖 I have read the MOLE Contributing Guide: https://github.com/csrc-sdsu/mole/blob/main/CONTRIBUTING.md
• 📖 I have read the MOLE Code of Conduct: https://github.com/csrc-sdsu/mole/blob/main/CODE_OF_CONDUCT.md

[optional] Are there any post deployment tasks we need to perform?

Update documentation (re the "extended" faces)

[optional] What gif best describes this PR or how it makes you feel?