[Numpy-discussion] Assignment from a list is slow in Numarray

Hello,

I am new to the list, sorry if you've been through this before.

I am trying to do some FEM computations using Petsc, to which I have written Python bindings using Swig. That involves passing arrays around, which I found delightfully simple with NA_{Input,Output,Io}Array. Numeric seems more difficult for output and bidirectional arrays.

My code for reading a triangulation from a file went roughly like this:

coord = zeros( (n_vertices, 2), Float) for v in n_vertices: coord[ v, :] = [float( s) for s in file.readline().split()]

This was taking quite a bit of time with ~50000 vertices and ~100000 elements, for which three integers per element are read in a similar manner. I found it was faster to loop explicitly:

coord = zeros( (n_vertices, 2), Float) for v in n_vertices: for j, c in enumerate( [float( s) for s in file.readline().split()]): coord[ v, j] = c

Morally this uglier code with an explicit loop should not be faster but it is with Numarray. With Numeric assignment from a list has reasonable performance. How can it be improved for Numarray?