[Numpy-discussion] Fwd: GPU Numpy

Sturla Molden sturla@molden...
Thu Sep 10 04:11:22 CDT 2009


Citi, Luca skrev:
> That is exactly why numexpr is faster in these cases.
> I hope one day numpy will be able to perform such
> optimizations.
>   
I think it is going to require lazy evaluation. Whenever possible, an 
operator would just return a symbolic representation of the operation. 
This would gradually build up a tree of operators and buffers. When 
someone tries to read the data from an array, the buffer is created 
on-demand by flushing procratinated expressions. One must be sure that 
the buffers referenced in an incomplete expression never change. This 
would be easiest to ensure with immutable buffers.  Numexpr is the kind 
of  back-end a system like this would require.  But a lot of the code in 
numexpr can be omitted because Python creates the parse tree; we would 
not need the expression parser in numexpr as frontend. Well... this plan 
is gradually getting closer to a specialized SciPy JIT-compiler. I would 
be fun to make if I could find time for it.

Sturla Molden




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