2010/1/23 Alan G Isaac <ais...@american.edu>: > Suppose x and y are conformable 2d arrays. > I now want x to become a duplicate of y. > I could create a new array: > x = y.copy() > or I could assign the values of y to x: > x[:,:] = y > > As expected the latter is faster (no array creation). > Are there better ways?
If both arrays are "C contiguous", or more generally contiguous blocks of memory with the same strided structure, you might get faster copying by flattening them first, so that it can go in a single memcpy(). For really large arrays that use complete pages, some low-level hackery involving memmap() might be able to make a shared copy-on-write copy at almost no cost until you start modifying one array or the other. But both of these tricks are intended for the regime where copying the data is the expensive part, not fabricating the array object; for that, I'm not sure you can accelerate things much. Anne _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
