Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
Hi all, I am trying to smooth an image using SMOOTH function in IDL. However i want to see how the SMOOTH routine is written because when I tried to write the routine myself, it takes a bit longer time than SMOOTH function. I tried to search for it in IDL lib but i couldn't locate it. Same is true for convolution (CONVOL) and FFT. Can anyone tell where these functions are located in IDL libraries ? Vaibhav Pant
They don't use direct convolution They do something like this code temp = total(x, /CUMULATIVE) result = shift(temp,n)- temp The example is 1d, but it is possible to do the same thing in 2d and 3d
On Wednesday, December 3, 2014 3:08:02 PM UTC+5:30, Sergey Anfinogentov wrote: > They don't use direct convolution > They do something like this code > > temp = total(x, /CUMULATIVE) > result = shift(temp,n)- temp > > The example is 1d, but it is possible to do the same thing in 2d and 3d Thanks for the reply. It is a nice trick. Still would like to know where these routines are present in IDL library. If anyone has any idea please do let me know?
On 03.12.2014 11:35, Vaibhav Pant wrote: > Still would like to know where these routines are present in IDL library. They are likely written in C, and they are probably shipped compiled and protected, to avoid that people look into it... Cheers, Fabien
On Wednesday, December 3, 2014 2:45:48 AM UTC-6, Vaibhav Pant wrote: > Hi all, > I am trying to smooth an image using SMOOTH function in IDL. However i want to see how the SMOOTH routine is written because when I tried to write the routine myself, it takes a bit longer time than SMOOTH function. I tried to search for it in IDL lib but i couldn't locate it. Same is true for convolution (CONVOL) and FFT. Can anyone tell where these functions are located in IDL libraries ? > > Vaibhav Pant Seems to me this provides what Smooth does: http://exelisvis.com/docs/SMOOTH.html