
From:  jdonner 
Subject:  Re: matrix of variables? < thanks 
Date:  Fri, 30 May 2003 18:53:39 0500 
Useragent:  Mozilla/5.0 (X11; U; Linux i686; enUS; rv:1.4b) Gecko/20030513 
Jeff wrote:
I'm trying to solve a nonlinear equation with 25 vars, and it works when I number them from x(1) .. x(25) but,they naturally are a 2D array of variables, is there some way I can I use matrix notation for convenience?When I try to say this: function y = f (x) g = 0.9; # center parts y(2,2) = 1 * x(2,2) + (1/4)*g*(x(1,2) + x(2,1) + x(2,3) + x(3,2)); y(2,3) = 1 * x(2,3) + (1/4)*g*(x(1,3) + x(2,2) + x(2,4) + x(3,3)); ... more I get: error: invalid column index = 2 error: evaluating binary operator `*' near line 4, column 13 error: evaluating binary operator `+' near line 4, column 22 error: evaluating assignment expression near line 4, column 8 error: called from `f' error: fsolve: evaluation of usersupplied function failed Is there a way to do this?
Heber Farnsworth wrote:
Define x as a vector and then reshape it into a matrix within the function. x = reshape(x,5,5);
Thanks for that. Also, zeros(5,5) works as far as declaring x and y as 2D. I have to reshape at the end (I think) but at least octave is not complaining. Thanks again,
Jeff  Octave is freely available under the terms of the GNU GPL. Octave's home on the web: http://www.octave.org How to fund new projects: http://www.octave.org/funding.html Subscription information: http://www.octave.org/archive.html 
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