comp.lang.idl-pvwave archive - RDF feed
type: channel
description: Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
items: a newbie question on code efficiency

a newbie question on code efficiency
type: item
description: Dear group members, i have a little challenge for you which i stumbled into.. i tried to write a program which takes a 3d array, sets a cutoff at a certain level and then creates a mask of all values above that level. the mask has to be 1 and 0. i came up with this code, but could never get rid of the loop. any suggestions on how to get rid of the loop? i would prefer array operators for speed :) ;----------------------------------------------------------- ------ PRO MAKE_MASK a = dialog_pickfile() b = READ_BINARY(a, DATA_TYPE=1, DATA_DIMS=[160,256,256]) b_dims = size(b) x_dim = b_dims[1] y_dim = b_dims[2] z_dim = b_dims[3] cutoff = 180 e = b for i = 0, (x_dim-1) do begin for j = 0, (y_dim-1) do begin for k = 0, (z_dim-1) do begin if e[i,j,k] lt cutoff then e[i,j,k]=0 if e[i,j,k] ge cutoff then e[i,j,k]=1 endfor endfor endfor ; and so on to use the mask further in the program END
creator: gogosgogos
date: 2001-08-18T02:54:19-00:00