Re: Philosophy of for loops

[Craig Markwardt <craigmnet(at)cow.physics.wisc.edu>]

landsman@my-deja.com writes:
> (1) for j=0,2047 do for i=0,2047 do outarr[i,j] = median(inarr[*,i,j])
> 
> (2) for j=0,2047 do begin
>     for i=0,2047 do begin
>         outarr[i,j] = median(inarr[*,i,j])
>     endfor
>     endfor
> 
> Form (1) is slightly faster, but the calculation cannot be interrupted
> with a Control-C.   Also, it is my impression that the speed difference
> is less than it used to be, and that form (2) is now better optimized.

I hadn't realized these were different!  My choice between the two
forms usually revolves around stylistic concerns, i.e., does the thing
fit on the line.  My guess is that form (2) is a little slower
*because* it is doing the keyboard checking.  I have some roundabout
evidence that this is true.

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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