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Fix Accumbounds output for functions at negative infinity #23753

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Merged
merged 2 commits into from
Jul 12, 2022
Merged

Fix Accumbounds output for functions at negative infinity #23753

merged 2 commits into from
Jul 12, 2022

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faze-geek
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@faze-geek faze-geek commented Jul 10, 2022 •
edited by anutosh491
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References to other Issues or PRs

Fixes #23751

Brief description of what is fixed or changed

At S.NegativeInfinity, limits do not give expected accumbounds output. That has been fixed here basically by returning inverse of the ouput at S.Infinity.

Examples on this branch -

>>> limit((cos(x) + 1)**(1/x), x, -oo)
AccumBounds(1, oo)
>>> limit((sin(x)**2)**(1/x), x, -oo)
AccumBounds(1, oo)

Other comments

Relevant tests have been added, along with the tests for #18473 because of the similarity.

Release Notes

  • series
    • Fixes leading term for exponential functions involving AccumBounds based arguments for limits being calculated at NegativeInfinity.

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sympy-bot commented Jul 10, 2022 •
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Hi, I am the SymPy bot (v167). I'm here to help you write a release notes entry. Please read the guide on how to write release notes.

Your release notes are in good order.

Here is what the release notes will look like:

  • series
    • Fixes leading term for exponential functions involving AccumBounds based arguments for limits being calculated at NegativeInfinity. (#23753 by @faze-geek)

This will be added to https://github.com/sympy/sympy/wiki/Release-Notes-for-1.11.

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#### References to other Issues or PRs
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Fixes #23751

#### Brief description of what is fixed or changed
At `S.NegativeInfinity`, limits do not give expected accumbounds output. That has been fixed here basically by returning inverse of the ouput at `S.Infinity`.

Examples on this branch - 
```
>>> limit((cos(x) + 1)**(1/x), x, -oo)
AccumBounds(1, oo)
>>> limit((sin(x)**2)**(1/x), x, -oo)
AccumBounds(1, oo)
```

#### Other comments
Relevant tests have been added, along with the tests for #18473 because of the similarity.

#### Release Notes

<!-- Write the release notes for this release below between the BEGIN and END
statements. The basic format is a bulleted list with the name of the subpackage
and the release note for this PR. For example:

* solvers
  * Added a new solver for logarithmic equations.

* functions
  * Fixed a bug with log of integers.

or if no release note(s) should be included use:

NO ENTRY

See https://github.com/sympy/sympy/wiki/Writing-Release-Notes for more
information on how to write release notes. The bot will check your release
notes automatically to see if they are formatted correctly. -->

<!-- BEGIN RELEASE NOTES -->
* series
  * Fixes leading term for exponential functions involving AccumBounds based arguments for limits being calculated at NegativeInfinity.
<!-- END RELEASE NOTES -->

Update

The release notes on the wiki have been updated.

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github-actions bot commented Jul 10, 2022 •
edited
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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)


       before           after         ratio
     [77f1d79c]       [de249495]
     <sympy-1.10.1^0>                 
+        21.1±1μs         64.5±4μs     3.05  matrices.TimeMatrixExpression.time_MatAdd
+        95.0±6ms        158±0.8ms     1.66  sum.TimeSum.time_doit



Full benchmark results can be found as artifacts in GitHub Actions

(click on checks at the top of the PR).

      		
    

  





        


            

            
            

              
            

        

      


      

            
  
  

    
  
    
    

  

  

  


    












      

  
        

  

      

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Looks good enabling auto-merge. I have when made some changes in the release notes to make it more accurate. Thanks

      		
    

  





        


            

            
            

              
            

        

      


      

            
  
  

    
  
    
    

  

  

  


    












      

  
          

  
  

  
    
            @anutosh491
  anutosh491

enabled auto-merge

    July 12, 2022 09:41    
    




  
 
  

    
  

  



        @anutosh491
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        merged commit 06fc97a
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    Jul 12, 2022

  







  

  
  

  
      @faze-geek
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    deleted the
    
      
        fix_accumbounds
    
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    July 12, 2022 11:11    
    













  
  

    

      

  




      


    


    

      

        
      

  
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Successfully merging this pull request may close these issues.



  
          
      Fix AccumBounds based output for limit((sin(x)**2)**(1/x), x, -oo)



  
  



      
    

  




      

    

  
      

  

    

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