2008/7/9 Charles R Harris <[EMAIL PROTECTED]>: > > On Wed, Jul 9, 2008 at 2:34 PM, Marlin Rowley <[EMAIL PROTECTED]> > wrote: >> >> Thanks Chuck, but I wasn't quit clear with my question. >> >> You answered exactly according to what I asked, but I failed to mention >> needing the dot product instead of just the product. >> >> So, >> >> v dot A = v' >> >> v'[0] = v[0]*A[0] + v[1]*A[1] + v[2]*A[2] >> v'[1] = v[0]*A[3] + v[1]*A[4] + v[2]*A[5] >> v'[2] = v[0]*A[6] + v[1]*A[7] + v[2]*A[8] >> > > There is no built in method for this specific problem (stacks of vectors and > matrices), but you can make things work: > > sum(A.reshape((-1,3))*v, axis=1) > > You can do lots of interesting things using such manipulations and newaxis. > For instance, multiplying stacks of matrices by stacks of matrices etc. I > put up a post of such things once if you are interested.
This particular instance can be viewed as a matrix multiplication (np.dot(A.reshape((-1,3)),v) I think). Anne _______________________________________________ Numpy-discussion mailing list Numpy-discussion@scipy.org http://projects.scipy.org/mailman/listinfo/numpy-discussion
