On 2010-07-15, at 12:38 PM, Emmanuel Bengio <beng...@gmail.com> wrote:
> Hello, > > I have a list of 4x4 transformation matrices, that I want to "dot with" > another list of the same size (elementwise). > Making a for loop that calculates the dot product of each is extremely slow, > I thought that maybe it's due to the fact that I have thousands of matrices > and it's a python for loop and there's a high Python overhead. > > I do something like this: > >> for a,b in izip(Rot,Trans): > >> c.append(numpy.dot(a,b)) If you need/want more speed than the solution Chuck proposed, you should check out Cython and Tokyo. Cython lets you write loops that execute at C speed, whereas Tokyo provides a Cython level wrapper for BLAS (no need to go through Python code to call NumPy). Tokyo was designed for exactly your use case: lots of matrix multiplies with relatively small matrices, where you start noticing the Python overhead. David _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
