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• physics.quantum

  • Added a precedence attribute to CG to fix latex rendering (#21769 by @redeboer)

  • Fixed argument order of the math in the CG documentation (#21769 by @redeboer)

This will be added to https://github.com/sympy/sympy/wiki/Release-Notes-for-1.9.

#### References to other Issues or PRs

- Fixes #18781
- Fixes #21001


#### Brief description of what is fixed or changed

- Fixed the order of the formula in the docstring (#18781)
- Added a link to the Particle Data Group for comparing the doctests
- Improved the LaTeX rendering so that it also renders if a `CG` is squared, for instance (#21001)


#### Release Notes

<!-- BEGIN RELEASE NOTES -->
* physics.quantum
  * Added a precedence attribute to `CG` to fix latex rendering
  * Fixed argument order of the math in the `CG` documentation
<!-- END RELEASE NOTES -->

Update

The release notes on the wiki have been updated.

The LaTeX thing should be fixed by fixing the precedence in the printer. If you look at precedence.py, it looks like it needs to define a precedence attribute (this stuff really needs to be documented).

The LaTeX thing should be fixed by fixing the precedence in the printer. If you look at precedence.py, it looks like it needs to define a precedence attribute (this stuff really needs to be documented).

Ah ok, yeah that sounds like a better solution. Perhaps it's also a solution to #19661 and #20959?

As for #18781, I want to look into this a bit further, because it seems c3a1a40 is not the correct solution.

The LaTeX thing should be fixed by fixing the precedence in the printer. If you look at precedence.py, it looks like it needs to define a precedence attribute (this stuff really needs to be documented).

@asmeurer is this the idea? c07fc47

Benchmark results from GitHub Actions

Lower numbers are good, higher numbers are bad. A ratio less than 1
means a speed up and greater than 1 means a slowdown. Green lines
beginning with + are slowdowns (the PR is slower then master or
master is slower than the previous release). Red lines beginning
with - are speedups.

Significantly changed benchmark results (PR vs master)

Significantly changed benchmark results (master vs previous release)

       before           after         ratio
     [ed9a550f]       [12b7787c]
     <sympy-1.8^0>                 
-      9.83±0.01s       5.04±0.02s     0.51  integrate.TimeIntegrationRisch02.time_doit(100)
-      9.92±0.02s       4.96±0.07s     0.50  integrate.TimeIntegrationRisch02.time_doit_risch(100)
+        83.2±2μs       3.28±0.2ms    39.35  matrices.TimeDiagonalEigenvals.time_eigenvals
-      5.65±0.2ms       3.38±0.2ms     0.60  solve.TimeRationalSystem.time_linsolve(10)
-     3.77±0.07ms      2.43±0.03ms     0.65  solve.TimeSparseSystem.time_linsolve_eqs(30)

Full benchmark results can be found as artifacts in GitHub Actions
(click on checks at the top of the PR).

I would put the precedence on the class itself, rather than in precedence.py, since the latex printer is also defined there. I believe you can define precedence = PRECEDENCE["Pow"] - 1 on the class, although you may have to read the source code in the printer to verify that this is correct. I don't know enough about the object itself to confirm if this is the correct precedence for it.

Ah yes that makes more sense --> 2f5dd66

Hadn't noticed precedence() also checks class attributes:

Looks good. Can you add release notes entries for the changes?

Looks good. Can you add release notes entries for the changes?

Done 👌

Looks good, thanks!