[Numpy-discussion] ANN: Numexpr 1.4 released

Francesc Alted faltet@pytables....
Sun Aug 1 06:33:52 CDT 2010


After the Theano talk in last EuroSciPy I suddenly realized that it would not 
be too difficult to implement a multi-threaded version of Numexpr.  Well, as 
usual I was terribly wrong and it took me a *long* week to do the job :-/

Anyway the thing is done now, so... enjoy!

Note for PyTables users:  Numexpr does not include changes in the API/ABI, so 
the upgrade from 1.3.1 is recommended.

 Announcing Numexpr 1.4

Numexpr is a fast numerical expression evaluator for NumPy.  With it,
expressions that operate on arrays (like "3*a+4*b") are accelerated
and use less memory than doing the same calculation in Python.

What's new

The main improvement in this version is the support for
multi-threading in pure C.  Threading in C provides the best
performance in nowadays multi-core machines.  In addition, this avoids
the GIL that hampers performance in many Python apps.

Just to wet your appetite, look into this page where the
implementation is briefly described and where some benchmarks are


In case you want to know more in detail what has changed in this
version, see:


or have a look at RELEASE_NOTES.txt in the tarball.

Where I can find Numexpr?

The project is hosted at Google code in:


And you can get the packages from PyPI as well:


Share your experience

Let us know of any bugs, suggestions, gripes, kudos, etc. you may


Francesc Alted

More information about the NumPy-Discussion mailing list