Can't define functions in Matlab

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Pedro
Pedro on 4 Sep 2012
Hello everyone, I have version R2012a of matlab and I would like to define this function to create direccional fields on first order differential equations. I created a notepad file with this code on it and exchanged the extension from .txt to .m and placed it on MATLAB/R2012a but it doesnt work. What am I doing wrong? Is it the folder? I also tried to put the code directily on matlab and run it but it failed.
function dirfield(f,tval,yval)
[tm,ym]=meshgrid(tval,yval);
dt = tval(2) - tval(1);
dy = yval(2) - yval(1);
yp=feval(vectorize(f),tm,ym);
s = 1./max(1/dt,abs(yp)./dy)*0.35;
h = ishold;
quiver(tval,yval,s,s.*yp,0,'.r'); hold on;
quiver(tval,yval,-s,-s.*yp,0,'.r');
if h
hold on
else
hold off
end
axis([tval(1)-dt/2,tval(end)+dt/2,yval(1)-dy/2,yval(end)+dy/2])
I would apreciate your help!
  1 Comment
Jan
Jan on 4 Sep 2012
What does "placed it on MATLAB/R2012a" exactly mean?

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Accepted Answer

Matt Fig
Matt Fig on 4 Sep 2012
At the command prompt, type: edit
Now paste your code into the window that opens up. Then save it. From the commamd prompt use the same name as you saved the file.

More Answers (2)

Elizabeth
Elizabeth on 4 Sep 2012
Your function name must match the file name you save it under. Could this be the issue?

Pedro
Pedro on 4 Sep 2012
Edited: Pedro on 4 Sep 2012
Thanks, I did what you said and it saved it on MATLAB/R2012a/bin , it had to be there. By the way, do these programs work on mathematica too?

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