Implements Grid.compute_skewness(..., method="equiangle")

[Sevans711]

Closes #1686

Overview

Creates Grid.compute_skewness and implements Grid.compute_skewness(..., method="equiangle"). This computes the skewness of all faces based on the equiangle method. See #1686 for more detailed description.

Similarly to Grid.compute_face_node_angles, the result is an xarray.DataArray by default, but can be returned as a UxDataArray if desired, by setting as_uxarray=True.

Tiny expansion of scope: clarifies in _compute_face_node_angles_convex docstring that the angles there are returned in radians.

Expected Usage

import uxarray as ux

grid_path = "/path/to/grid.nc"
data_path = "/path/to/data.nc"

uxds = ux.open_dataset(grid_path, data_path)
grid = uxds.uxgrid   # or use: ux.open_grid(grid_path)

# result is an xarray.DataArray by default
skewness = grid.compute_skewness()

# Easier to visualize when getting result as UxDataArray instead:
skewness_as_uxarray = grid.compute_skewness(as_uxarray=True)
skewness_as_uxarray.plot()

PR Checklist

General

• An issue is created and linked
• Added appropriate labels (if your uxarray repo permissions allow it)
• Filled out Overview and Expected Usage (if applicable) sections

Testing & Benchmarking

• Adequate tests are created if there is new functionality
• Tests are not too basic (such as simply calling a function and nothing else)
• Tests cover all major paths in your new functions
• [N/A] If this PR could affect performance, ran ASV benchmarks and confirmed they show expected behavior (add a new benchmark if necessary)

Documentation

• Docstrings have been added to all new functions
• [N/A] Docstrings have been updated with any function changes
• User (public) functions have been added to docs/api.rst
• Internal (private) function names start with an underscore (_)

AI Disclosure

AI Usage: GitHub Copilot's inline code suggestions, plus chats with Claude, ChatGPT, Gemini for learning about skewness.

• I take responsibility for all AI-generated content in my PR.
• I have tested all AI-generated content in my PR.