If you don't mind losing the original permutation (it's overwritten), you can use Base.permute!! (unexported). However, in most cases, this is still actually slower than A[p]. Not sure how that would be for sorting rows/columns.
Kevin On Wed, Mar 11, 2015 at 7:49 AM, Davide Lasagna <[email protected]> wrote: > Well, thanks Tim for pointing this out. > > Cheers, > > Davide > > > On Wednesday, March 11, 2015 at 2:42:38 PM UTC, Tim Holy wrote: >> >> Good that you clarified that, but are you aware that permute! makes a >> copy of >> the permutation? So there's no memory savings, and it's about 4x slower >> than >> an out-of-place copy. >> >> --Tim >> >> On Wednesday, March 11, 2015 07:09:38 AM Davide Lasagna wrote: >> > But A[p, :] makes copies, and I want it to be in place. >> > >> > Davide >> > >> > On Wednesday, March 11, 2015 at 2:02:31 PM UTC, Tim Holy wrote: >> > > A[p, :] >> > > >> > > --Tim >> > > >> > > On Wednesday, March 11, 2015 05:49:47 AM Davide Lasagna wrote: >> > > > Hi, >> > > > >> > > > >> > > > permute!(v, p) permutes the elements of v according to the >> permutation >> > > > vector p. >> > > > >> > > > Is there any equivalent built in function for permuting rows of a >> > > >> > > matrix? >> > > >> > > > Given the memory layout of julia matrices it should not be too >> difficult >> > > >> > > to >> > > >> > > > have a similar function for matrices as well. >> > > > >> > > > Thanks, >> > > > >> > > > Davide >> >>
