Enhance ZX simplification algorithms for multi-control gate validation #1429
Description
Background
As discussed in PR #1380 (#1380 (comment)), the current tests for multi-control gates (MCX, MCZ, MCRZ, CCZ, CRZ) serve as placeholders until the ZX simplification algorithms are properly updated.
Current State
The existing tests verify that multi-control gates transform to ZX diagrams and that concatenating a gate with its inverse yields identity. However, they don't fully validate the correctness of the ZX construction against known decompositions.
Objectives
- Enhance ZX simplification algorithms to properly handle multi-control gate decompositions
- Update corresponding tests to validate multi-control gates against known decompositions (e.g., H-MCZ-H for MCX)
- Ensure the ZX functionality construction is correctly implemented for all multi-control variants
Related Work
- PR Add multi-control functionality #1380 introduced initial multi-control functionality
- Tests affected: MultiControlX, MultiControlZ, CCZ, CRZ, MultiCZ, MultiControlRZ, and related variants
Requested by: @keefehuang