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Merged
merged 2 commits into from
May 3, 2022
Merged

Improve handling of inert primes #23450

merged 2 commits into from
May 3, 2022

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skieffer
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@skieffer skieffer commented May 1, 2022

References to other Issues or PRs

Fixes #23402

Brief description of what is fixed or changed

  • Ensure the second generator alpha of a prime ideal is identically 0 whenever p is inert, fixing PrimeIdeal generator should be reduced #23402.

  • While we're on the subject, we also provide an is_inert property in the PrimeIdeal class, and use this to govern printing.

Other comments

Release Notes

  • polys
    • Repair representation of prime ideals for inert primes

skieffer added 2 commits May 1, 2022 10:11
@skieffer
Provide PrimeIdeal.is_inert property, and use in printing
206c668
@skieffer
Ensure inert primes have 0 second generator.
4b537d2 
We only need to fix this in the "easy case," since it is already correctly
implemented in the "hard case."

In the easy case, `T` stays irreducible over `FF(p)`, so if we lift back to `ZZ`, and
reduce mod `T` (as we were doing), we can get a non-zero poly, hence the bug.

In the hard case, the `_prime_decomp_maximal_ideal()` function passes an empty
list of generators to `_two_elt_rep()`, which ensures `alpha` is `0`.
@skieffer skieffer added the polys label May 1, 2022
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sympy-bot commented May 1, 2022 •
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Hi, I am the SymPy bot (v163). 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:

  • polys
    • Repair representation of prime ideals for inert primes (#23450 by @skieffer)

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

Click here to see the pull request description that was parsed. 
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#### References to other Issues or PRs
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Fixes #23402


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

* Ensure the second generator `alpha` of a prime ideal is identically `0` whenever `p` is inert, fixing #23402.

* While we're on the subject, we also provide an `is_inert` property in the `PrimeIdeal` class, and use this to govern printing.


#### Other comments


#### Release Notes

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  * Added a new solver for logarithmic equations.

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<!-- BEGIN RELEASE NOTES -->
* polys
  * Repair representation of prime ideals for inert primes
<!-- END RELEASE NOTES -->

Update

The release notes on the wiki have been updated.

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github-actions bot commented May 1, 2022

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]       [352b1826]
     <sympy-1.10.1^0>                 
+      99.1±0.5ms          181±1ms     1.83  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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I don't know so much about this topic but the changes here look okay to me.

      		
    

  





        


            

            
            

              
            

        

      


      

            
  
  

    
  
    
    

  

  

  


    












      

  
      



  

  @jksuom





  



    

      

  

    

        
    
    

  


      
          
  
      
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        May 3, 2022


      
    


  





      


        



  
    

      
          
Looks fine to me too.

      		
    

  





        


            

            
            

              
            

        

      


      

            
  
  

    
  
    
    

  

  

  


    












      

  
          
 
  

    
  

  



        @jksuom
  jksuom



        merged commit ed4e06e
      into

      
  
    sympy:master
  


    May 3, 2022

  
















  
  

    

      

  




      


    


    

      

        
      

  
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Successfully merging this pull request may close these issues.



  
          
      PrimeIdeal generator should be reduced



  
  



      
    

  




      

    

  
      

  

    

      4 participants
    

    

        
          @skieffer 
        
          @sympy-bot 
        
          @oscarbenjamin 
        
          @jksuom