[SciPy-user] partially reading a file...
Wed Aug 6 14:06:42 CDT 2008
On Wed, Aug 6, 2008 at 8:14 PM, Travis E. Oliphant
> fred wrote:
>> Travis E. Oliphant a écrit :
>>> Absolutely memory mapping still applies --- it's a perfect application
>>> for it. But, you will probably need a 64-bit system.
>> No problem.
>>> Memory mapping is how the OS handles "virtual memory" which uses disk
>>> space to increase main memory. You are just using that idea directly
>>> with a memory mapped file.
>> Thanks for the hint.
> More directly:
> Use numpy.memmap --- look at the docstring for example use and help on
> all the arguments available. But, something like this (untested):
> a = numpy.memmap(<filename>, mode='r', dtype=float, shape=(nx,ny,nz))
> b = a[:nx/4,:ny/4,:nz/4]
We should already get used to using "//" instead "/" if we want the
result to be integer:
So that is:
> b = a[:nx//4,:ny//4,:nz//4]
... I'm just trying to advertise the 'future' (py3.0 or today: 'python
-Qnew' ) so-called "true division"-feature ....
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