There is no API for Ax - r, you can do MatMult(A,x,b) VecAXPY(b,-1.0,r)
On Aug 15, 2011, at 3:14 AM, "Gong Ding" <gdiso at ustc.edu> wrote: > Hi, > I have a linear system f(x)=Ax-b=r > For solving it, I must build rhs vector b=Ax-r. > However, I can't find some direct API to do this. > MatMultAdd only support b=Ax+r. > > At preset, I am using > VecSet(L, -1.0); > VecPointwiseMult(r, r, L); // r <- -r > MatMultAdd(A, x, r, b); > > Any better method? > > Gong Ding > > > > > > >
