align divmod with Python behavior

[smichr]

References to other Issues or PRs

Brief description of what is fixed or changed

>>> divmod(S(4), S(-2.0))
(-3, -2.0) <----- should be (-2, -0.0)

Other comments

Release Notes

• core
  • divmod(a,b) now gives i, r with abs(r) < abs(b) when a*b is a negative float, e.g. divmod(S(4), S(-2.0)) -> (-2, 0.0)

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• core
  • divmod(a,b) now gives i, r with abs(r) < abs(b) when a*b is a negative float, e.g. divmod(S(4), S(-2.0)) -> (-2, 0.0) (#25648 by @smichr)

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#### References to other Issues or PRs
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#### Brief description of what is fixed or changed
```python
>>> divmod(S(4), S(-2.0))
(-3, -2.0) <----- should be (-2, -0.0)
```


#### Other comments


#### Release Notes

<!-- Write the release notes for this release below between the BEGIN and END
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* solvers
  * Added a new solver for logarithmic equations.

* functions
  * Fixed a bug with log of integers. Formerly, `log(-x)` incorrectly gave `-log(x)`.

* physics.units
  * Corrected a semantical error in the conversion between volt and statvolt which
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<!-- BEGIN RELEASE NOTES -->
* core
    * divmod(a,b) now gives i, r with abs(r) < abs(b) when a*b is a negative float, e.g. `divmod(S(4), S(-2.0)) -> (-2, 0.0)`
<!-- END RELEASE NOTES -->

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)

| Change   | Before [8059df73] <sympy-1.12^0>   | After [baae1d96]    |   Ratio | Benchmark (Parameter)                                                |
|----------|------------------------------------|---------------------|---------|----------------------------------------------------------------------|
| -        | 103±2ms                            | 67.2±0.6ms          |    0.65 | integrate.TimeIntegrationRisch02.time_doit(10)                       |
| -        | 101±2ms                            | 66.3±0.3ms          |    0.66 | integrate.TimeIntegrationRisch02.time_doit_risch(10)                 |
| +        | 25.6±0.05μs                        | 45.7±0.2μs          |    1.79 | integrate.TimeIntegrationRisch03.time_doit(1)                        |
| -        | 8.23±0.01ms                        | 4.47±0.02ms         |    0.54 | logic.LogicSuite.time_load_file                                      |
| -        | 2.45±0ms                           | 786±2μs             |    0.32 | polys.TimePREM_LinearDenseQuadraticGCD.time_op(3, 'sparse')          |
| -        | 12.0±0.02ms                        | 2.35±0ms            |    0.2  | polys.TimePREM_LinearDenseQuadraticGCD.time_op(5, 'sparse')          |
| -        | 438±0.5μs                          | 97.7±0.4μs          |    0.22 | polys.TimePREM_QuadraticNonMonicGCD.time_op(1, 'sparse')             |
| -        | 5.58±0.02ms                        | 434±0.8μs           |    0.08 | polys.TimePREM_QuadraticNonMonicGCD.time_op(3, 'sparse')             |
| -        | 12.2±0.03ms                        | 1.31±0ms            |    0.11 | polys.TimePREM_QuadraticNonMonicGCD.time_op(5, 'sparse')             |
| -        | 7.37±0.02ms                        | 4.73±0.02ms         |    0.64 | polys.TimeSUBRESULTANTS_LinearDenseQuadraticGCD.time_op(2, 'sparse') |
| -        | 32.0±0.06ms                        | 14.4±0.03ms         |    0.45 | polys.TimeSUBRESULTANTS_LinearDenseQuadraticGCD.time_op(3, 'sparse') |
| -        | 8.32±0.02ms                        | 1.40±0ms            |    0.17 | polys.TimeSUBRESULTANTS_QuadraticNonMonicGCD.time_op(1, 'sparse')    |
| -        | 19.2±0.04ms                        | 11.1±0.03ms         |    0.58 | polys.TimeSUBRESULTANTS_QuadraticNonMonicGCD.time_op(2, 'sparse')    |
| -        | 246±0.6ms                          | 84.4±0.05ms         |    0.34 | polys.TimeSUBRESULTANTS_QuadraticNonMonicGCD.time_op(3, 'sparse')    |
| -        | 7.36±0.02ms                        | 643±5μs             |    0.09 | polys.TimeSUBRESULTANTS_SparseGCDHighDegree.time_op(3, 'sparse')     |
| -        | 31.7±0.1ms                         | 1.02±0ms            |    0.03 | polys.TimeSUBRESULTANTS_SparseGCDHighDegree.time_op(5, 'sparse')     |
| -        | 726±1μs                            | 237±1μs             |    0.33 | polys.TimeSUBRESULTANTS_SparseNonMonicQuadratic.time_op(1, 'sparse') |
| -        | 7.49±0.01ms                        | 241±2μs             |    0.03 | polys.TimeSUBRESULTANTS_SparseNonMonicQuadratic.time_op(3, 'sparse') |
| -        | 19.6±0.07ms                        | 245±0.9μs           |    0.01 | polys.TimeSUBRESULTANTS_SparseNonMonicQuadratic.time_op(5, 'sparse') |
| -        | 191±0.3μs                          | 106±0.3μs           |    0.55 | solve.TimeMatrixOperations.time_rref(3, 0)                           |
| -        | 365±0.3μs                          | 129±0.9μs           |    0.35 | solve.TimeMatrixOperations.time_rref(4, 0)                           |
| -        | 37.5±0.1ms                         | 16.3±0.2ms          |    0.43 | solve.TimeSolveLinSys189x49.time_solve_lin_sys                       |

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

[oscarbenjamin]

Release Notes

• core

  • divmod(a,b) now gives i, r with abs(r) < abs(b) when a*b is a negative float, e.g. divmod(S(4), S(-2.0)) -> (2, 0.0)

Should this say (-2, 0.0)?

[oscarbenjamin]

Should this say (-2, 0.0)?

I just corrected the release note

[oscarbenjamin]

Looks good.