[SciPy-user] ANN: Numexpr 1.2 released

Francesc Alted faltet@pytables....
Wed Feb 11 07:20:49 CST 2009

 Announcing Numexpr 1.2

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.

The main feature added in this version is the support of the Intel VML 
library (many thanks to Gregor Thalhammer for his nice work on this!).  
In addition, when the VML support is on, several processors can be used 
in parallel (see the new `set_vml_num_threads()` function).

When the VML support is on, the computation of transcendental functions 
(like trigonometrical, exponential, logarithmic, hyperbolic, power...) 
can be accelerated quite a few.  Typical speed-ups when using one 
single core for contiguous arrays are around 3x, with peaks of 7.5x 
(for the pow() function).  When using 2 cores the speed-ups are around 
4x and 14x respectively.

In case you want to know more in detail what has changed in this
version, have a look at the release notes:


Where I can find Numexpr?

The project is hosted at Google code in:


And you can get the packages from PyPI as well:


How it works?



for a detailed description of the package.

Share your experience

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


Francesc Alted

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