Hi, I am trying to permute a vector for 1000 times for which I am using for loop.Within the for loop, I am doing some matrix operations which is taking a lot of time. I am looking for a way to permute the vector 1000 times and do the operations of the matrix without using for loop. This a snippet of my code: for (i in 2:1000){ y.permute = permute(y.permute) ### permute the vector F.stats = calPseudoStat(y.permute,table.Gij) ## call the function which does some matrix calculation and calculates a pseudo statistics F.stats.vec = append(F.stats.vec, F.stats) ## add the Pseudo Statistics in a vector. } Thanks. -- Regards, Ayush Raman [[alternative HTML version deleted]]