[Numpy-discussion] Make array uncopyable

Dag Sverre Seljebotn d.s.seljebotn@astro.uio...
Wed Mar 23 14:54:12 CDT 2011


On 03/23/2011 08:05 PM, Daniel Lepage wrote:
> Hi all,
>     Is there a way to mark an array as uncopyable? If you have very
> large data arrays some numpy functions will cause MemoryErrors because
> behind the scenes they e.g. transpose the arrays into Fortran order to
> feed them into Fortran libraries (numpy.linalg.svd is an example of
> this). It would be great if there were a way to mark an array as "too
> big to copy" so that an attempt to call transpose() or astype() would
> raise an exception immediately instead of clobbering the machine's
> memory first, but I don't know of any flag that does this.
>
> I suppose I could always subclass ndarray and redefine transpose(),
> astype(), etc., but it'd be nice if there were an easier way.

This is a bit OT, but if your problem is simply wanting to fail hard 
when using too much memory instead of swapping to disk, then on Unix 
systems you can use "ulimit -v" to limit how much memory your 
application can use. When I do this the MemoryError is quick and painless.

Dag Sverre


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