>No! matrix objects use matrix multiplication for *. You seem to need >elementwise >multiplication.
No! when you mult a vector with itself transposed, the diagonal of the resulting matrix is the squares of each error (albeit you do a lot of extra calc), then sum the squares, ie trace(). Its a nifty trick, if you don't have too much data 25000x25000 matrix in mem and youre using matricies ie. batch learning. The actual equation includes multiply by 1/2*(sum of the squares), but mean squared error can be more telling about error and cross entropy is even better, becuase it tells you how well youre predicting the posterior probabilies... -- http://mail.python.org/mailman/listinfo/python-list
