I think that you could use sub(A,:,2:2:4) for BLAS, but not sub(A,:,[2,4]) because the indexing has to be with ranges for BLAS to be able to extract the right elements of the matrix.
2015-03-29 17:34 GMT-04:00 Dominique Orban <[email protected]>: > Sorry if this is another [:] kind of question, but I can't seem to find > the right syntax to call BLAS.gemm! on part of an array. The piece of code > > julia> n = 10; m = 5; idx = [2, 4]; > julia> C = rand(n, m); A = rand(n, m); B = rand(m, m); > julia> BLAS.gemm!('N', 'N', 1.0, A[:,idx], B[:,idx], 1.0, C[:,idx]); > > won't modify C. I'm simply trying to do > > C[:,idx] += A[:,idx] * B[:,idx]; > > What's the right syntax here? > > It seems ArrayViews.jl might be the way to go, but it doesn't let me do > view(A, :, idx). > > Thanks! >
