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Merged
merged 3 commits into from
Jun 2, 2022
Merged

do not use solve in idiff #23560

merged 3 commits into from
Jun 2, 2022

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smichr
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@smichr smichr commented May 31, 2022 •
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References to other Issues or PRs

closes #23554

Brief description of what is fixed or changed

A more optimized internal solving process is used to calculate the derivatives. The existing tests already run faster. The expression below runs about 4X faster relative to master:

eq=x**3 + y**3 - (3*x*y**2 - x - 1)*(x**2 + x*y + y**2 - 10)
t=time()
y1=idiff(eq, y,x)
time()-t
t=time()
y2=idiff(eq, y,x,2)
time()-t

The equation given on the issue page runs about 200X faster.

Other comments

It seems like this should be faster than it is.... Would using cse help in any way?

Release Notes

  • geometry
    • idiff is more efficient at calculating derivatives

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sympy-bot commented May 31, 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:

  • geometry
    • idiff is more efficient at calculating derivatives (#23560 by @smichr)

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. 
<!-- Your title above should be a short description of what
was changed. Do not include the issue number in the title. -->

#### References to other Issues or PRs
<!-- If this pull request fixes an issue, write "Fixes #NNNN" in that exact
format, e.g. "Fixes #1234" (see
https://tinyurl.com/auto-closing for more information). Also, please
write a comment on that issue linking back to this pull request once it is
open. -->

closes #23554 

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

A more optimized internal solving process is used to calculate the derivatives. The existing tests already run faster. The expression below runs about 4X faster relative to master:

```python
eq=x**3 + y**3 - (3*x*y**2 - x - 1)*(x**2 + x*y + y**2 - 10)
t=time()
y1=idiff(eq, y,x)
time()-t
t=time()
y2=idiff(eq, y,x,2)
time()-t
```

The equation given on the issue page runs about 200X faster.

#### Other comments

It seems like this should be faster than it is.... Would using `cse` help in any way?

#### 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 -->
* geometry
  * idiff is more efficient at calculating derivatives
<!-- END RELEASE NOTES -->

Update

The release notes on the wiki have been updated.

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github-actions bot commented May 31, 2022 •
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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]       [b1cf21e1]
     <sympy-1.10.1^0>                 
+         133±1ms          232±2ms     1.74  sum.TimeSum.time_doit



Full benchmark results can be found as artifacts in GitHub Actions

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

      		
    

  





        


            

            
            

              
            

        

      


      

            
  
  

    
  
    
    

  

  

  


    












      

  
          
 
  

    
  

  



        @smichr
  smichr



        merged commit ff00553
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    sympy:master
  


    Jun 2, 2022

  












      

  
        

  

      

  asmeurer
  

  
          

            
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                  Jun 2, 2022
                
            
            
          


          



              
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                sympy/geometry/util.py

          
        


      
          
  

    
      
    
    

          


              

              

            
                      deq = eq.diff(x)

            
          

          


              

              

            
                      b = deq.xreplace({dydx: S.Zero})

            
          

          


              

              

            
                      a = (deq - b).xreplace({dydx: S.One})

            
          

          


              

              

            
                      yp = factor_terms(expand_mul(cancel((-b/a).subs(derivs)), deep=False))

            
          

    








  

    

        

        

  

    

        
    
    

  


      
          
  
      
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Do we even need full blown cancel here? That can be expensive if the expression is large.

    

  
  



    


        

      
  
  

    
  
    
    

  

  

  



          

      
    








    


  









  








  












  
  

    

      

  




      


    


    

      

        
      

  
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Successfully merging this pull request may close these issues.



  
          
      idiff should use solve_linear (or better)



  
  



      
    

  




      

    

  
      

  

    

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          @smichr 
        
          @sympy-bot 
        
          @asmeurer