Re: [Numpy-discussion] broadcasting question

On Thursday, August 30, 2012, Neal Becker wrote:

I think this should be simple, but I'm drawing a blank

I have 2 2d matrixes

Matrix A has indexes (i, symbol) Matrix B has indexes (state, symbol)

I combined them into a 3d matrix:

C = A[:,newaxis,:] + B[newaxis,:,:] where C has indexes (i, state, symbol)

That works fine.

Now suppose I want to omit B (for debug), like:

C = A[:,newaxis,:]

In other words, all I want is to add a dimension into A and force it to broadcast along that axis. How do I do that?

np.tile would help you there, I think. Ben Root