Dne 8.11.2010 14:01, Jed Brown napsal(a): > On Mon, Nov 8, 2010 at 13:47, Daniel Langr <daniel.langr at gmail.com > <mailto:daniel.langr at gmail.com>> wrote: > > Great, helps much, that is something I was hoping for :). As for > now, we can generate matrix in-order. In the future it seems we will > need to generate matrix in "transposed" order, e.g. row-by-row order > for the lower triangular part. But then I suppose we will need to > use MatMultTranspose() or MatCreateTranspose() if the performance > won't suffer much (I have not tried it yet, so I have no idea about > it for now.) > > > Well, the distinguishing property of symmetric matrices is that they are > equal to their transpose. :-) > > For non-symmetric matrices, MatMultTranspose (perhaps accessed as > MatMult via MatCreateTranspose) is about the same speed as MatMult. > > Jed
I meant something else but wrote it wrong, shame on me :). I thought that when I use MatCreateTranspose() for a symmetric matrix, I will be able to preallocate and set values for lower part (instead of upper part) in row-by-row order, as I generate them. But I am not sure about it. Daniel
