Extract/Improve Polyhedron class

[joscao]

• extract polyhedron class from loki/transform/transform_loop.py into loki/analyse/util_polyhedron.py
• extract testing from tests/test_transform_loop.py into tests/test_util_polyhedron.py
• add __repr__ to Polyhedron class
• add utility function for construction from_nested_loops
• add is_empty functionality

[codecov]

Codecov Report

Merging #178 (cfc998c) into main (af8ec9f) will decrease coverage by 0.02%.
The diff coverage is 92.80%.

@@            Coverage Diff             @@
##             main     #178      +/-   ##
==========================================
- Coverage   92.14%   92.12%   -0.02%     
==========================================
  Files          90       91       +1     
  Lines       16690    16713      +23     
==========================================
+ Hits        15379    15397      +18     
- Misses       1311     1316       +5     

Flag	Coverage Δ
lint_rules	96.22% <ø> (ø)
loki	92.09% <92.80%> (-0.03%)	⬇️
transformations	91.40% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
loki/transform/transform_loop.py	96.12% <100.00%> (+0.03%)	⬆️
loki/analyse/util_polyhedron.py	92.68% <92.68%> (ø)

[joscao]

Code-checks is complaining about a cyclic import, but in the tests/test_build.py which I cant seem to reproduce (there linter is running fine) on my local machine. Could somebody help me out please?

Error: tests/test_build/test_build.py:1:0: R0401: Cyclic import (loki -> loki.lint -> loki.lint.linter -> loki.transform -> loki.transform.transform_loop -> loki.analyse.util_polyhedron) (cyclic-import)
Error: tests/test_build/test_build.py:1:0: R0401: Cyclic import (loki -> loki.transform -> loki.transform.transform_loop -> loki.analyse.util_polyhedron) (cyclic-import)

[reuterbal]

Thanks, this looks great. We need to take care of resolving the type hint problem with 3.8, and it would be wise to add another test for the construction from nested loops that ensures the resulting polyhedron looks fine.

[reuterbal]

Fantastic, many thanks. I think this is ready for merging.