Ah, hah. In [3]: c = b.reshape((256,256,150), order='F')
Ok, I needed more coffee. If I do it this way (without the transpose), it should be as fast as c=b.reshape((150,256,256)), right? It is just changing the stride (or something like that)? Or is it going to be faster without changing the order? Thanks for the help. Ryan May-3 wrote: > > On Tue, May 12, 2009 at 2:51 PM, brechmos <cr...@brechmos.org> wrote: > >> So, in Numpy I have to reshape it so the "slices" are in the first >> dimension. Obviously, I can do a b.transpose( (1,2,0) ) to get it to >> look >> like Matlab, but... >> >> I don't understand why the index ordering is different between Matlab and >> Numpy. (It isn't a C/Fortran ordering thing, I don' think). > > > Actually, that's precisely the reason. > > >> Is the data access faster if I have b without the tranpose, or can I >> transpose it so it "looks" like Matlab without taking a hit when I do >> imshow( b[:,:,0] ). >> > > It's going to be faster to do it without the transpose. Besides, for > numpy, > that imshow becomes: > > imshow(b[0]) > > Which, IMHO, looks better than Matlab. > > Ryan > > -- > Ryan May > Graduate Research Assistant > School of Meteorology > University of Oklahoma > > _______________________________________________ > Numpy-discussion mailing list > Numpy-discussion@scipy.org > http://mail.scipy.org/mailman/listinfo/numpy-discussion > > -- View this message in context: http://www.nabble.com/Matlab-Numpy-index-order-tp23509178p23509345.html Sent from the Numpy-discussion mailing list archive at Nabble.com. _______________________________________________ Numpy-discussion mailing list Numpy-discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
