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Multi cores support in Theano
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Parallel element wise op with openmp
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Beacuse element wise ops work on every tensor entry indipedently they can be
easly parallelized using openmp.

To use openmp you must set the openmp flag in Theano configuration.

Yuo can use the flag openmp_elemwise_minsize to set the minimum tensor size
for which the operation is parallelized because for short tensor using opemp
can slow down the operation.

If it is no specified the default value (200000) is used.

For simple(fast) operation you can obtain a speed up for very long tensor
while for more complex operation you ca obtain a good speed up also for not
too long tensor. 
There is a script (elemwise_openmp_speedup.py in theano/misc/) which you can
use to choose that value for your machine.
The script run two elemwise operation (a fast and a slow one) for a vector of
size openmp_elemwise_minsize with and without openmp and show the time
difference between the two cases.





