Add dontcare argument to simplify_logic

[oscargus]

References to other Issues or PRs

Another part of #22753

Brief description of what is fixed or changed

simplify_logic now has a dontcare keyword argument, so that one can simplify the expression under the assumption that the dontcare-expression does not matter. Useful in general, but especially for Piecewise simplification where one then can set the previous conditions to don't care.

Other comments

Release Notes

• logic
  • simplify_logic now has a dontcare keyword argument for simplifying under don't care-conditions.

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• logic
  • simplify_logic now has a dontcare keyword argument for simplifying under don't care-conditions. (#23986 by @oscargus)

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Another part of #22753

#### Brief description of what is fixed or changed
`simplify_logic` now has a `dontcare` keyword argument, so that one can simplify the expression under the assumption that the `dontcare`-expression does not matter. Useful in general, but especially for Piecewise simplification where one then can set the previous conditions to don't care.

#### Other comments


#### Release Notes

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  * Added a new solver for logarithmic equations.

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<!-- BEGIN RELEASE NOTES -->
* logic
    * `simplify_logic` now has a `dontcare` keyword argument for simplifying under don't care-conditions.
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Update

The release notes on the wiki have been updated.

[github-actions]

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
     [41d90958]       [fb7c59c1]
     <sympy-1.11.1^0>                 
-         950±2μs          611±1μs     0.64  solve.TimeSparseSystem.time_linear_eq_to_matrix(10)
-        2.75±0ms         1.14±0ms     0.42  solve.TimeSparseSystem.time_linear_eq_to_matrix(20)
-     5.49±0.02ms         1.68±0ms     0.31  solve.TimeSparseSystem.time_linear_eq_to_matrix(30)

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

[oscarbenjamin]

Speaking as someone who only recently learned what "don't care" means in logic maybe it would be good to have a reference for this:
https://en.wikipedia.org/wiki/Don%27t-care_term

[oscarbenjamin]

Looks good to me

[oscargus]

Rebased, the link added in three relevant positions and some crosslinking between POSform and SOPform.

[oscarbenjamin]

I think a less trivial example would be better. Perhaps this:

In [6]: simplify_logic(x ^ y, dontcare=x & y)
Out[6]: x ∨ y

Here it is not as simple as just supposing that the dontcare is False.

[oscargus]

I can modify it as part of next PR. Agreed that it is probably better.

[oscarbenjamin]

Looks good to me. +1 to merge.