[Numpy-discussion] Objected-oriented SIMD API for Numpy

[Francesc Alted]

A Wednesday 21 October 2009 07:44:39 Mathieu Blondel escrigué:
> Hello,
>
> About one year ago, a high-level, objected-oriented SIMD API was added
> to Mono. For example, there is a class Vector4f for vectors of 4
> floats and this class implements methods such as basic operators,
> bitwise operators, comparison operators, min, max, sqrt, shuffle
> directly using SIMD operations.
[clip]

It is important to stress out that all the above operations, except probably 
sqrt, are all memory-bound operations, and that implementing them for numpy 
would not represent a significant improvement at all.

This is because numpy is a package that works mainly with arrays in an 
element-wise way, and in this scenario, the time to transmit data to CPU 
dominates, by and large, over the time to perform operations.

Among other places, you can find a detailed explication of this fact in my 
presentation at latest EuroSciPy:

http://www.pytables.org/docs/StarvingCPUs.pdf

Cheers,

-- 
Francesc Alted