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RE: How do I replace this for-loop?
From: |
de Almeida, Valmor F. |
Subject: |
RE: How do I replace this for-loop? |
Date: |
Sat, 05 Jul 2008 14:24:30 -0400 |
Does this give you any speed up?
output(n(:,1),n(:,2)) = 1;
--
Valmor
> -----Original Message-----
> From: Robert Macy [mailto:address@hidden
> Sent: Friday, July 04, 2008 5:49 PM
> To: address@hidden
> Subject: How do I replace this for-loop?
>
> What's the best way to replace this for-loop?
>
> Given an array, n, of datapoints, such that:
>
> >> size(n)
> rows = 27000
> columns = 2
>
> where n(:,1) are all the integer x values, and
> n(:,2) are all the integer y values,
> both integer values are in the range of 1 to 101
>
> I slowly did it this way:
>
> output=zeros(101,101);
> for i=1:27000
> output( n(i,1),n(i,2) ) = output( n(i,1),n(i,2) ) + 1;
> endfor
>
> as you all know this is fairly slow.
> What's a simple way to replace this for-loop?
>
> Robert
>
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