On Wed, Apr 28, 2010 at 2:12 PM, Alan G Isaac <aisaac@american.edu> wrote:

On 4/28/2010 12:05 PM, Travis Oliphant wrote:

A proposal was made to allow "calling a NumPy array" to infer dot product:

a(b) is equivalent to dot(a,b)

a(b)(c) would be equivalent to dot(dot(a,b),c)

Here is a related ticket that proposes a more explicit alternative: adding a ``dot`` method to ndarray. http://projects.scipy.org/numpy/ticket/1456

FWIW, I have borrowed a convenience function chain_dot originally from pandas that works for me as a stop gap for more readable code. def chain_dot(*arrs): """ Returns the dot product of the given matrices. Parameters ---------- arrs: argument list of ndarrays Returns ------- Dot product of all arguments. Example ------- >>> import numpy as np >>> from scikits.statsmodels.tools import chain_dot >>> A = np.arange(1,13).reshape(3,4) >>> B = np.arange(3,15).reshape(4,3) >>> C = np.arange(5,8).reshape(3,1) >>> chain_dot(A,B,C) array([[1820], [4300], [6780]]) """ return reduce(lambda x, y: np.dot(y, x), arrs[::-1]) Skipper