Re: [Numpy-discussion] Any idea to run the dot-product on many arrays

On 01/13/2011 05:04 PM, EMMEL Thomas wrote:

Hi,

I need to rotate many vectors (x,y,z) with a given rotation matrix (3x3). I can always do

for v in vectors: tv += np.dot(mat, v)

where mat is my fixed matrix (or array of arrays) and v is a single array. Is there any efficient way to use an array of vectors to do the transfomation for all of these vectors at once?

numpy.dot(rotationmatrix , coordinates.T).T Where coordinates is a n*3 matrix of n stacked vectors in rows. It works with vectors stacked in column without the the two transpose. It's even possible to apply a symmetry operation to a bunch of second rank tensors in one go. Pascal