Announcement: New faster Common Subexpression Elimination (CSE) implementation

[Cristóvão Sousa]

Hi all,

I just want to announce that a new implementation of Common Subexpression Elimination (CSE) routine has been merged into master (PR: https://github.com/sympy/sympy/pull/2355).

This new implementation is really faster, especially when no external optimizations are performed (the default now).

And there is a new option for even faster results: order='none'.

Here is a comparison example: http://nbviewer.ipython.org/5986996

As it can be seen, for the no optimizations case, there is a reduction from _1 minute and half_  to  _580 ms_,

from the previous to the new implementation.

With the order='none' option, the new implementation drops to _91 ms_!

For all of you who wasn't using CSE because of it being a bottleneck, CSE must be reconsidered again.

Thanks,

Happy code,

Cristóvão D. Sousa

[Cristóvão Sousa]

On Sunday, September 8, 2013 1:55:12 AM UTC+1, Cristóvão Sousa wrote:

Hi all,

I just want to announce that a new implementation of Common Subexpression Elimination (CSE) routine has been merged into master (PR: https://github.com/sympy/sympy/pull/2355).

This new implementation is really faster, especially when no external optimizations are performed (the default now).

And there is a new option for even faster results: order='none'.

Here is a comparison example: http://nbviewer.ipython.org/5986996

As it can be seen, for the no optimizations case, there is a reduction from _1 minute and half_  to  _580 ms_,

from the previous to the new implementation.

150x faster.

 

With the order='none' option, the new implementation drops to _91 ms_!

1000x faster.

[Matthew Rocklin]

That's awesome.  Can I suggest that you blog about this and push it to planet.sympy.org?

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[Ondřej Čertík]

On Sat, Sep 7, 2013 at 7:06 PM, Cristóvão Sousa <cri...@gmail.com> wrote:
> On Sunday, September 8, 2013 1:55:12 AM UTC+1, Cristóvão Sousa wrote:
>>
>> Hi all,
>>
>> I just want to announce that a new implementation of Common Subexpression
>> Elimination (CSE) routine has been merged into master (PR:
>> https://github.com/sympy/sympy/pull/2355).
>>
>> This new implementation is really faster, especially when no external
>> optimizations are performed (the default now).
>> And there is a new option for even faster results: order='none'.
>>
>> Here is a comparison example: http://nbviewer.ipython.org/5986996
>> As it can be seen, for the no optimizations case, there is a reduction
>> from _1 minute and half_ to _580 ms_,
>> from the previous to the new implementation.
>
>
> 150x faster.
>
>>
>> With the order='none' option, the new implementation drops to _91 ms_!
>
>
> 1000x faster.

This is amazing. Thanks Cristóvão for your hard work. This will be
very very useful to a lot of people.

Ondrej

>
>>
>>
>> For all of you who wasn't using CSE because of it being a bottleneck, CSE
>> must be reconsidered again.
>>
>> Thanks,
>> Happy code,
>> Cristóvão D. Sousa
>>

[Cristóvão Sousa]

Done: https://csousahome.wordpress.com/2013/09/09/faster-common-subexpression-elimination-cse-in-sympy/.

How can I push it to the planet?

[Matthew Rocklin]

I think we need to add you to something in the planet.sympy repo.  Aaron, Ondrej, what file is appropriate here?

[Aaron Meurer]

planet.ini

Aaron Meurer

[Ondřej Čertík]

Just send a PR against this repo:

https://github.com/sympy/planet.sympy.org

once we merge it, the planet should automatically pick it up. This
assumes you don't make a syntax error. If you do, then I might need to
debug by hand on the server.

[Cristóvão Sousa]

I think adding this is enough:

[http://csousahome.wordpress.com/tag/sympy/feed/]


name = Cristóvão Sousa

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[Cristóvão Sousa]

Ok, PR done (https://github.com/sympy/planet.sympy.org/pull/19).