I had a question regarding the use of temporary in IDL. I wanted to re-order a 3D array. Suppose the array is vol = IntArr( 512, 512, 287 ) I sorted the Z dimension and got the indices. The command I then used was vol = temporary( vol[ *, *, sorted_z] ) Despite this, the memory used is still the same if I don’t use temporary (almost 5 times the size of the array)Is this the correct way to use temporary? If I am using it correctly, is it just the IDL way of reading columns and rows? Is there another way of 3 D sorting an array that is faster than this method? Thanks, Rohit