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From: "Natalie Sin Hwee " <sin.ng09@imperial.ac.uk>
Newsgroups: comp.soft-sys.matlab
Subject: Re: finding distances that satisfy the equation ? (confused :'( , please help)
Date: Mon, 29 Mar 2010 10:01:07 +0000 (UTC)
Organization: Imperial College
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> a hint:
> - create a list [IR,IC] of those nodes only that satisfy your condition...
> - then, compute their distance in a simple loop...
> 
>      [ir,ic]=find(sect1);
>      lst=[ir,ic];
> % now, loop through your list LST...
> 
> just a thought...
> us

=====

thanks us!! i did that and it works!!!!! awesome!! ive added in:

sect1=((0<theta) & (theta<(0.25*pi)));

[g1,k1]=find(sect1>=1); first=[g1,k1];
first_sort=sort(first,2);

L1=length(k1); 
dist1=zeros(L1,1);
for n=1:L1
dist1(n,1)=sqrt((x(1,first_sort(n,2))-x(1,first_sort(n,1))).^2+...
    (y(1,first_sort(n,2))-y(1,first_sort(n,1))).^2);
end


and that returns me a the 'distance between nodes' corresponding to what i've found in 'first' - column1 wrt to column 2 'nodes'

any idea how i can separate them out into the different 'nodes' wrt to column 1. e.g.

node 1 + 2,7,8,9,(random whatever it has given me)

my aim is to find,

the nearest node to each node within that angle (0 to pi/4)...

(will be repeated as applied to the 8 sectors in the circle) 

*omg sorry this is getting more and more confusing !! ^^ 

thanks lots just for reading through it!
Natalie