Am 30.10.2012 um 14:35 schrieb Dimitris K.: > For clarification, since I can't find anything in the docs, I want to ask. > > Say I want to compute the following: > > y = \alpha x op(A) + \beta y (where x,y are vectors and A is a matrix), >
So if op(A)=A your vectors are row-rectors. In this case the operation is equivalent to y = \alpha A^T x + \beta y where x and y are column-vectors. Other cases of op(A) can be treated analogously. As BLAS does not distinguish between col- and row-vectors you just can use gemv. If elements are complex valued there is a problem though. Officially gemv in BLAS does not support an operation like y = \alpha conj(A) x + \beta y which would be required in your case if op(A)=A^H. However, (I think) some BLAS implementation actually support it (TRANSA='R'). Cheers, Michael
