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Re: "infinite" nested for [message #86643 is a reply to message #86642]

Mon, 25 November 2013 08:37

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

Chrisss writes:

Another way you can improve this code is to only calculate unchanging
variable once, and outside the loops. For example, you have this, in
which you calculate the number of elements of X, which never changes,
six times!

for i=0, dx-1 do begin
for j=0,dy-1 do begin
y=reform (Im[i,j,*],N_ELEMENTS(x)))
fitErrors=FLTARR(N_ELEMENTS(x))
T1values=FLTARR(N_ELEMENTS(x))
S0values=FLTARR(N_ELEMENTS(x))
fvalues=FLTARR(N_ELEMENTS(x))
for t=0,N_ELEMENTS(x)-1 do begin

This can be changed to this:

num_x = N_Elements(x)
fitErrors=FLTARR(num_x)
T1values=FLTARR(num_x)
S0values=FLTARR(num_x)
fvalues=FLTARR(num_x)
for i=0, dx-1 do begin
for j=0,dy-1 do begin
y=reform (Im[i,j,*],num_x)
for t=0,num_x-1 do begin

If you need to reinitialize your arrays inside the loop, then do this,
rather than re-allocating more memory. I think this is probably why your
program crashed after 12 hours. You ran out of dynamic memory on your
machine:

fitErrors=Temporary(fitErrors)*0.0
T1values=Temporary(T1values)*0.0
S0values=Temporary(S0values)*0.0
fvalues=Temporary(fvalues)*0.0

Cheers,

David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.idlcoyote.com/
Sepore ma de ni thue. ("Perhaps thou speakest truth.")

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[Message index]

		"infinite" nested for By: Chrisss on Mon, 25 November 2013 00:13
		Re: "infinite" nested for By: Kai Muehlbauer on Mon, 25 November 2013 00:27
		Re: "infinite" nested for By: Chrisss on Mon, 25 November 2013 02:24
		Re: "infinite" nested for By: Kai Muehlbauer on Mon, 25 November 2013 03:22
		Re: "infinite" nested for By: Chrisss on Mon, 25 November 2013 03:53
		Re: "infinite" nested for By: Kai Muehlbauer on Mon, 25 November 2013 04:12
		Re: "infinite" nested for By: Chrisss on Mon, 25 November 2013 06:56
		Re: "infinite" nested for By: Mats Löfdahl on Mon, 25 November 2013 07:38
		Re: "infinite" nested for By: Chrisss on Mon, 25 November 2013 08:18
		Re: "infinite" nested for By: David Fanning on Mon, 25 November 2013 08:37
		Re: "infinite" nested for By: Chrisss on Mon, 25 November 2013 10:00
		Re: "infinite" nested for By: Mats Löfdahl on Mon, 25 November 2013 10:25
		Re: "infinite" nested for By: Chrisss on Mon, 25 November 2013 11:24
		Re: "infinite" nested for By: Craig Markwardt on Tue, 26 November 2013 08:04
		Re: "infinite" nested for By: Chrisss on Tue, 26 November 2013 09:05

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