Hi All, I need some help with the package 'isotone'? I have a big matrix (long) and I want to apply 'lsSolver' possibly with 'activeSet' to each row of the matrix. The plan is to use function 'apply', I tried several ways, but didn't work. Not sure if the FUN is activeSet or lsSolver. If I use the loop, then it works, but very slow. for (i in 1:N) { x.iso[i,] <- activeSet(A,lsSolver,weights=rep(1,n),y=x[i,])$x } Can someone help me with this? Thanks, Annie [[alternative HTML version deleted]]