Include center

[mroethlin]

Technical Description

This PR introduces support for reductions including the center. Besides the matching and transpilation to SIR checks were added to ensure that the Offsets are consistent with the current iteration space also regarding the inclusion of the center

Resolves

Fixes #66

Example

Fill including the center

@stencil
def fill_with_center(
    sparse: Field[Origin + Edge > Cell > Edge],
    edge: Field[Edge],
):
    with levels_downward:
        with sparse[Origin + Edge > Cell > Edge]:
            sparse = edge[Origin + Edge > Cell > Edge]

Reduction including the center

@stencil
def reductions_with_center(
    a: Field[Edge], b: Field[Origin + Edge > Cell > Edge], c: Field[Edge]
):
    with levels_downward:
        a = sum_over(Origin + Edge > Cell > Edge, b*c[Origin + Edge > Cell > Edge])

Testing

Two tests representing the examples above were introduced

Dependencies

Depends on dawn PR 1081

[BenWeber42]

We'll do the PR feedback in a pair programming session.