[Numpy-discussion] 3D interpolation of large array

David Warde-Farley dwf@cs.toronto....
Sun Sep 13 22:55:43 CDT 2009


On 13-Sep-09, at 8:51 PM, brechmos wrote:

>
> I have a large dataset (e.g., 70 x 500 x 500) and want to  
> interpolate points
> (for example to double the size).  What it seems I want is:
>
> []: newx,newy,newz=mgrid[1:70:0.5,1:500:0.5,1:500:0.5]
> []: coords = array([newz, newy, newx])
> []: dout = np.map_coordinates(d, coords)

That's going to incur over 3 gigabytes of RAM (about a gig each for  
newx, newy, and newz), and you're running 32-bit Python. Not only do  
you likely not have enough physical memory (which can be solved  
somewhat by swapping), Python doesn't have enough memory address  
space. So in other words, no.

Compiling a 64-bit version of Python and NumPy would solve the problem.

David


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