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Re: correlation matrix [message #35462 is a reply to message #35323]

Wed, 11 June 2003 18:18

Craig Markwardt
Messages: 1869
Registered: November 1996

Senior Member

kevinlausten@hotmail.com (Kevin M. Lausten) writes:
> I have written code to create the correlation matix of a data cube,
> however, it seems to run slower than I would expect. I am I doing
> anything inefficiently?
>
> for r = 0, (nrows-1) do begin
> for c = 0, (ncols-1) do begin
> ;sum = 0
> for bb = 0, (nbands-1) do begin
> ref(bb) = in_cube(bb, c, r)
> ; 'ref' equals 'back_cube' for all values of 'bb' at location
> ; (c, r)
> endfor

Whatever the IN_CUBE() is, it will be the limiting factor in your
snippet, since it is in the innermost loop. If you can vectorize
IN_CUBE over BB then your routine should be faster.

Good luck,
Craig

--
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Craig B. Markwardt, Ph.D. EMAIL: craigmnet@cow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
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		correlation matrix By: kevinlausten on Wed, 11 June 2003 12:04
		Re: correlation matrix By: Craig Markwardt on Wed, 11 June 2003 18:18

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