gradient_mpas
This page is auto-generated from the rule's JSON by
tools/render_doc_plots.py. The discrete operator below is pretty-printed directly from the rule's replacement AST using EarthSciSerialization (earthsci_toolkit). Rules with a hand-authored page carry richer prose plus stencil and convergence diagrams; see the curated entries linked from the rule index.Pattern
Matches the §4.2 operator grad on the pattern grad($phi), dim=edge for grid family unstructured.
Discrete operator
Pretty-printed from the rule’s replacement AST ($-prefixed names are pattern variables bound by applies_to; grid metrics such as dx/dz are resolved by the grid):
out = (index($phi, index(cells_on_edge, i, 2)) − index($phi, index(cells_on_edge, i, 1)))/index(dc_edge, i)