I need to sort a double precision array and keep track of the indices, e.g. I need to know where an element in the sorted array was in the unsorted array (or basically I want to replicate the sort command in Matlab). I would like to use the mkl library and for the sole purpose of sorting I found the "dlasrt" subroutine, but I couldn't find anything to keep track of the indices. Is there any subroutine in mkl that will allow me to keep track of the indices? My array might be big, so I would like to avoid having to write a sorting subroutine. I am using fortran.