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fix corner case handling in log_to_real (used by ratint) #25900

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Merged
merged 1 commit into from
Nov 13, 2023
Merged

fix corner case handling in log_to_real (used by ratint) #25900

merged 1 commit into from
Nov 13, 2023

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@smichr smichr commented Nov 12, 2023 •
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References to other Issues or PRs

fix #25896 for case when C=0

Brief description of what is fixed or changed

Other comments

@oscarbenjamin comments here suggest that groebner rather than resultants may be a better way to handle rational polynomials. This PR is not changing the approach, just handling a corner case.

Release Notes

  • integrals
    • fixed bug in log_to_real which caused only the log part to be returned

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Hi, I am the SymPy bot. I'm here to help you write a release notes entry. Please read the guide on how to write release notes.

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Here is what the release notes will look like:

  • integrals
    • fixed bug in log_to_real which caused only the log part to be returned (#25900 by @smichr)

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fix #25896 for case when C=0

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


#### Other comments
@oscarbenjamin comments [here](https://github.com/sympy/sympy/issues/25896#issuecomment-1807191211) suggest that `groebner` rather than resultants may be a better way to handle rational polynomials. This PR is not changing the approach, just handling a corner case.

#### Release Notes

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  * Added a new solver for logarithmic equations.

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

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<!-- BEGIN RELEASE NOTES -->
* integrals
  * fixed bug in log_to_real which caused only the log part to be returned
<!-- END RELEASE NOTES -->

Update

The release notes on the wiki have been updated.

@smichr smichr changed the title fix corner case handling in ratint fix corner case handling in log_to_real (used by ratint) Nov 12, 2023
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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 [a00718ba]    | After [94be646c]    |   Ratio | Benchmark (Parameter)                                                |
|----------|----------------------|---------------------|---------|----------------------------------------------------------------------|
| -        | 68.1±0.6ms           | 44.4±0.3ms          |    0.65 | integrate.TimeIntegrationRisch02.time_doit(10)                       |
| -        | 66.6±0.8ms           | 44.0±0.3ms          |    0.66 | integrate.TimeIntegrationRisch02.time_doit_risch(10)                 |
| +        | 17.8±0.08μs          | 29.3±0.3μs          |    1.64 | integrate.TimeIntegrationRisch03.time_doit(1)                        |
| -        | 5.21±0.02ms          | 2.88±0.02ms         |    0.55 | logic.LogicSuite.time_load_file                                      |
| -        | 71.1±0.7ms           | 27.9±0.4ms          |    0.39 | polys.TimeGCD_GaussInt.time_op(1, 'dense')                           |
| -        | 25.7±0.3ms           | 17.1±0.2ms          |    0.67 | polys.TimeGCD_GaussInt.time_op(1, 'expr')                            |
| -        | 72.1±0.4ms           | 28.4±0.2ms          |    0.39 | polys.TimeGCD_GaussInt.time_op(1, 'sparse')                          |
| -        | 252±3ms              | 123±0.2ms           |    0.49 | polys.TimeGCD_GaussInt.time_op(2, 'dense')                           |
| -        | 255±1ms              | 123±0.6ms           |    0.48 | polys.TimeGCD_GaussInt.time_op(2, 'sparse')                          |
| -        | 655±3ms              | 367±2ms             |    0.56 | polys.TimeGCD_GaussInt.time_op(3, 'dense')                           |
| -        | 650±7ms              | 368±0.8ms           |    0.57 | polys.TimeGCD_GaussInt.time_op(3, 'sparse')                          |
| -        | 492±1μs              | 283±3μs             |    0.57 | polys.TimeGCD_LinearDenseQuadraticGCD.time_op(1, 'dense')            |
| -        | 1.77±0.01ms          | 1.04±0ms            |    0.59 | polys.TimeGCD_LinearDenseQuadraticGCD.time_op(2, 'dense')            |
| -        | 5.73±0.03ms          | 3.04±0.04ms         |    0.53 | polys.TimeGCD_LinearDenseQuadraticGCD.time_op(3, 'dense')            |
| -        | 446±3μs              | 227±1μs             |    0.51 | polys.TimeGCD_QuadraticNonMonicGCD.time_op(1, 'dense')               |
| -        | 1.46±0.01ms          | 661±2μs             |    0.45 | polys.TimeGCD_QuadraticNonMonicGCD.time_op(2, 'dense')               |
| -        | 4.79±0.01ms          | 1.63±0.01ms         |    0.34 | polys.TimeGCD_QuadraticNonMonicGCD.time_op(3, 'dense')               |
| -        | 368±3μs              | 206±1μs             |    0.56 | polys.TimeGCD_SparseGCDHighDegree.time_op(1, 'dense')                |
| -        | 2.44±0.01ms          | 1.20±0.02ms         |    0.49 | polys.TimeGCD_SparseGCDHighDegree.time_op(3, 'dense')                |
| -        | 9.78±0.06ms          | 4.23±0.01ms         |    0.43 | polys.TimeGCD_SparseGCDHighDegree.time_op(5, 'dense')                |
| -        | 355±4μs              | 167±2μs             |    0.47 | polys.TimeGCD_SparseNonMonicQuadratic.time_op(1, 'dense')            |
| -        | 2.41±0.02ms          | 884±8μs             |    0.37 | polys.TimeGCD_SparseNonMonicQuadratic.time_op(3, 'dense')            |
| -        | 9.55±0.05ms          | 2.69±0.03ms         |    0.28 | polys.TimeGCD_SparseNonMonicQuadratic.time_op(5, 'dense')            |
| -        | 993±8μs              | 416±1μs             |    0.42 | polys.TimePREM_LinearDenseQuadraticGCD.time_op(3, 'dense')           |
| -        | 1.70±0.01ms          | 501±2μs             |    0.29 | polys.TimePREM_LinearDenseQuadraticGCD.time_op(3, 'sparse')          |
| -        | 5.76±0.06ms          | 1.75±0.01ms         |    0.3  | polys.TimePREM_LinearDenseQuadraticGCD.time_op(5, 'dense')           |
| -        | 8.38±0.07ms          | 1.50±0.01ms         |    0.18 | polys.TimePREM_LinearDenseQuadraticGCD.time_op(5, 'sparse')          |
| -        | 287±1μs              | 62.7±0.2μs          |    0.22 | polys.TimePREM_QuadraticNonMonicGCD.time_op(1, 'sparse')             |
| -        | 3.30±0.02ms          | 386±3μs             |    0.12 | polys.TimePREM_QuadraticNonMonicGCD.time_op(3, 'dense')              |
| -        | 3.84±0.06ms          | 276±0.7μs           |    0.07 | polys.TimePREM_QuadraticNonMonicGCD.time_op(3, 'sparse')             |
| -        | 6.67±0.06ms          | 1.24±0.01ms         |    0.19 | polys.TimePREM_QuadraticNonMonicGCD.time_op(5, 'dense')              |
| -        | 8.50±0.1ms           | 840±2μs             |    0.1  | polys.TimePREM_QuadraticNonMonicGCD.time_op(5, 'sparse')             |
| -        | 5.02±0.04ms          | 2.98±0.02ms         |    0.59 | polys.TimeSUBRESULTANTS_LinearDenseQuadraticGCD.time_op(2, 'sparse') |
| -        | 11.7±0.05ms          | 6.31±0.02ms         |    0.54 | polys.TimeSUBRESULTANTS_LinearDenseQuadraticGCD.time_op(3, 'dense')  |
| -        | 22.2±0.2ms           | 9.13±0.06ms         |    0.41 | polys.TimeSUBRESULTANTS_LinearDenseQuadraticGCD.time_op(3, 'sparse') |
| -        | 5.36±0.1ms           | 866±7μs             |    0.16 | polys.TimeSUBRESULTANTS_QuadraticNonMonicGCD.time_op(1, 'sparse')    |
| -        | 12.8±0.2ms           | 7.06±0.04ms         |    0.55 | polys.TimeSUBRESULTANTS_QuadraticNonMonicGCD.time_op(2, 'sparse')    |
| -        | 99.0±0.8ms           | 25.4±0.09ms         |    0.26 | polys.TimeSUBRESULTANTS_QuadraticNonMonicGCD.time_op(3, 'dense')     |
| -        | 164±0.5ms            | 54.4±0.2ms          |    0.33 | polys.TimeSUBRESULTANTS_QuadraticNonMonicGCD.time_op(3, 'sparse')    |
| -        | 170±1μs              | 110±2μs             |    0.64 | polys.TimeSUBRESULTANTS_SparseGCDHighDegree.time_op(1, 'dense')      |
| -        | 362±2μs              | 214±1μs             |    0.59 | polys.TimeSUBRESULTANTS_SparseGCDHighDegree.time_op(1, 'sparse')     |
| -        | 4.16±0.02ms          | 822±10μs            |    0.2  | polys.TimeSUBRESULTANTS_SparseGCDHighDegree.time_op(3, 'dense')      |
| -        | 5.07±0.02ms          | 377±2μs             |    0.07 | polys.TimeSUBRESULTANTS_SparseGCDHighDegree.time_op(3, 'sparse')     |
| -        | 19.2±0.08ms          | 2.74±0ms            |    0.14 | polys.TimeSUBRESULTANTS_SparseGCDHighDegree.time_op(5, 'dense')      |
| -        | 22.0±0.2ms           | 622±8μs             |    0.03 | polys.TimeSUBRESULTANTS_SparseGCDHighDegree.time_op(5, 'sparse')     |
| -        | 487±2μs              | 135±1μs             |    0.28 | polys.TimeSUBRESULTANTS_SparseNonMonicQuadratic.time_op(1, 'sparse') |
| -        | 4.56±0.01ms          | 607±5μs             |    0.13 | polys.TimeSUBRESULTANTS_SparseNonMonicQuadratic.time_op(3, 'dense')  |
| -        | 5.18±0.03ms          | 137±1μs             |    0.03 | polys.TimeSUBRESULTANTS_SparseNonMonicQuadratic.time_op(3, 'sparse') |
| -        | 12.8±0.04ms          | 1.25±0ms            |    0.1  | polys.TimeSUBRESULTANTS_SparseNonMonicQuadratic.time_op(5, 'dense')  |
| -        | 13.4±0.3ms           | 140±2μs             |    0.01 | polys.TimeSUBRESULTANTS_SparseNonMonicQuadratic.time_op(5, 'sparse') |
| -        | 137±0.4μs            | 74.4±1μs            |    0.54 | solve.TimeMatrixOperations.time_rref(3, 0)                           |
| -        | 265±0.9μs            | 88.6±0.3μs          |    0.33 | solve.TimeMatrixOperations.time_rref(4, 0)                           |
| -        | 24.4±0.08ms          | 10.2±0.1ms          |    0.42 | 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).

      		
    

  





        


            

            
            

              
            

        

      


      

            
  
  

    
  
    
    

  

  

  


    












      

  
            







      

  
      



  

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        @oscarbenjamin
  oscarbenjamin



        merged commit 3dc7a42
      into

      
  
    sympy:master
  


    Nov 13, 2023

  







  

  
  

  
      @smichr
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    deleted the
    
      
        log_to_real
    
    branch

    November 13, 2023 12:53    
    













  
  

    

      

  




      


    


    

      

        
      

  
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      ratint(e,x).diff().equals(e) is not always True (terms lost)



  
  



      
    

  




      

    

  
      

  

    

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