Hi all, I'm sorry for what is probably a very simple question but despite looking I didn't manage to find anything. I have some code (solving linear differential equation) which is doing the following operation lots of times: S[:] = dot(A,S)+C here S is a (M,N) matrix, A is (M,M) and C is (M,1). M is usually smallish and N is largish. My question is, can this be turned into an inplace operation to save memory and time? As far as I can see, although some array functions allow you to specify the destination of the output, dot always generates a new array. So I would like to have something like this: dot(A,S, out=S) S+=C Ideally, I could do this in one line. I believe the BLAS DGEMM routine does what I want (if I converted C to a matrix rather than a vector). Is there any way to access this using Python and NumPy (e.g. something like numpy.blas.DGEMM) or would I need to use C code to do this? Many thanks in advance, Dan Goodman