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Newsgroups: comp.soft-sys.matlab
Subject: Re: (yet unsolved) how to Solve coupled ODEs
Date: Tue, 12 Feb 2013 18:26:05 +0000 (UTC)
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Xref: news.mathworks.com comp.soft-sys.matlab:788864

hi, I tried the following

[T,sols] = ode45(@yprime, [1 20],0.000001*ones(1,40)');

function dyds = odeeqns(s,y)
global a b c d
dyds1 = 1./y(1) .*(y(2) .* (d + y(2)./ s) - a .* y(1) .* sqrt(y(1).^2 + (b + y(2)).^2));
dyds2 = - (y(2) .* (b + y(2)) .* sqrt(y(1).^2 + (b + y(2)).^2))./y(1) - y(2)./s - c;
dyds = [dyds1 dyds2];
size(dyds) % 1 x 40
plot(dyds);hold on
return

same error message... The funny thing is that the code plots the vectors... but then shows the error message...

the problem is a profile described over a distance from 1 to 20 kms in this case...What am I doing wrong?