[SciPy-user] In-place matrix reordering

Antonino Ingargiola tritemio@gmail....
Wed Feb 25 09:58:46 CST 2009


2009/2/25 Gael Varoquaux <gael.varoquaux@normalesup.org>:
> On Wed, Feb 25, 2009 at 02:45:07PM +0100, Antonino Ingargiola wrote:
>> I've never used the N.memmap function so maybe I do something wrong
>> here. Any hints?
>
> use::
>
> from numpy.lib import format
> format.open_memmap

Is the difference between numpy.memmap and format.open_memmap only
that the latter will guess the correct shape and dtype of the array? I
did not found much documentation about memmap and what is the best
format for storing an ndarray.

I opened co and cor as mmap using  format.open_memmap but the command
cor[:,:] = co[:,u] gives the same error as before. I suspect that the
command creates a temp variable in RAM with the size of co. I can copy
the data in blocks, but the operation becomes really slow (> 10 min).

Thanks for the suggestions so far.

   ~ Antonio


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