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Fix SymPy 1.5+ compatibility issue in Kronecker delta simplification for spin enumeration#24

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Fix SymPy 1.5+ compatibility issue in Kronecker delta simplification for spin enumeration#24
Copilot wants to merge 4 commits intopep621from
copilot/fix-d7f83362-c492-4dd8-bc7c-7ec29c51a79d

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Copilot AI commented Sep 4, 2025 •
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The simplify_deltas method in drudge/term.py was failing to properly simplify Kronecker deltas involving spin enumeration symbols (UP, DOWN) when summed over spin dummy variables. This caused test failures in tests/spin_one_half_test.py, specifically in the test_restricted_parthole_drudge_simplification test.

The issue manifested as:

# This should simplify to 1 but remained unsimplified
sum_{sigma0} KroneckerDelta(SpinOneHalf(0), sigma0)  # where sigma0 ∈ [0,2)

The root cause was in the proc_delta function, which had two problems:

  1. Intersection handling: The original code assumed specific argument orders when stripping domain intersections from SymPy solveset results, which became unreliable in SymPy 1.5+.

  2. Integer range resolution: When solving KroneckerDelta(SpinOneHalf(0), sigma0), the solution sigma0 = 0 (an integer) couldn't be validated against the spin range because try_resolve_range(0, ...) returned None.

Fixed by:

  • Making intersection handling more robust by filtering out domain arguments regardless of order
  • Adding logic to validate integer solutions directly against range bounds when range resolution fails
  • Ensuring that integer solutions within [start, end) bounds are recognized as valid substitutions

This fix maintains backward compatibility while resolving the SymPy version compatibility issue that prevented proper simplification of spin-related tensor expressions.

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coveralls commented Sep 4, 2025 •
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Pull Request Test Coverage Report for Build 17477535967

Details

  • 8 of 10 (80.0%) changed or added relevant lines in 1 file are covered.
  • No unchanged relevant lines lost coverage.
  • Overall coverage increased (+0.02%) to 87.837%
Changes Missing Coverage Covered Lines Changed/Added Lines %
drudge/term.py 8 10 80.0%
Totals Coverage Status
Change from base Build 17469345399: 0.02%
Covered Lines: 3784
Relevant Lines: 4308
💛 - Coveralls

Copilot AI and others added 2 commits September 4, 2025 21:11
@chenpeizhi
Fix simplify_deltas intersection handling for SymPy 1.5+ compatibility
d36abc2 
Co-authored-by: chenpeizhi <8114085+chenpeizhi@users.noreply.github.com>
@chenpeizhi
Add comprehensive tests verifying the simplify_deltas fix
a1e9e42 
Co-authored-by: chenpeizhi <8114085+chenpeizhi@users.noreply.github.com>
Copilot AI requested a review from chenpeizhi September 4, 2025 21:16
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chenpeizhi commented Sep 4, 2025

@copilot Somehow, your previous attempt was interrupted. Continue working on this issue. I noticed that you had difficulty implementing drudge. As I mentioned, you should follow the Installation section in README.md to install drudge and all its dependencies. You should use uv. The .github/workflows/copilot-setup-steps.yml file can be referenced for the steps that need to be taken for the installation on Ubuntu. If you follow the instructions, you don't have to install the dependencies separately; uv pip will handle them for you. Be sure to set export DUMMY_SPARK=1 in your bash environment to use dummy_spark.

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chenpeizhi commented Sep 4, 2025

@copilot You still had difficulty installing the package. Again, do not separately install dummyrdd. It is a dependency specified in pyproject.toml. uv should be able to properly install drudge and all its dependencies using uv, which uses the pyproject.toml, setup.py, and uv.lock in the repo. And be sure to set export DUMMY_SPARK=1 before you run the tests. Before you start, please first read all my previous instructions, all your previous session notes, and all your commits in this PR (since you were interrupted in the previous two attempts). I think you were on the right track in the attempt. Continue the hard work.

@chenpeizhi
Fix integer range resolution in proc_delta for spin enumeration simpl…
dfd64d2 
…ification

Co-authored-by: chenpeizhi <8114085+chenpeizhi@users.noreply.github.com>
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Copilot AI commented Sep 4, 2025 •
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@copilot You still had difficulty installing the package. Again, do not separately install dummyrdd. It is a dependency specified in pyproject.toml. uv should be able to properly install drudge ...

I've successfully installed the project using uv and all dependencies as instructed. The key fix I implemented resolves the SymPy 1.5+ compatibility issue in the simplify_deltas method. The problem was in the proc_delta function - it couldn't properly handle integer solutions when resolving Kronecker deltas over spin enumeration ranges.

The failing test test_restricted_parthole_drudge_simplification now passes, confirming that the fix resolves the original issue with summation of Kronecker deltas over spin dummies. Commit: dfd64d2

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Copilot AI changed the title [WIP] A test failed in tests/spin_one_half_test.py since the simplify_deltas method in drudge/term.py failed to properly simplify a tensor term with a Kronecker delta. Specifically, the summation of a Kronecker delta over a spin dumm failed to simplify... Fix SymPy 1.5+ compatibility issue in Kronecker delta simplification for spin enumeration Sep 4, 2025
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chenpeizhi commented Sep 5, 2025

Superseded by d9f2cb7

@chenpeizhi chenpeizhi closed this Sep 5, 2025
@chenpeizhi chenpeizhi deleted the copilot/fix-d7f83362-c492-4dd8-bc7c-7ec29c51a79d branch September 17, 2025 01:48
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