Dimension mismatch for using Runge Kutta 4 order methods

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Walter Roberson
Walter Roberson on 16 Aug 2012
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Answers (1)

Kye Taylor
Kye Taylor on 15 Aug 2012
If dx/dt = [0,0,.4,0] for a vector x, then the exact solution is
x(t) = [x0, x1, 0.4*t+x2, x3]
where x0,x1,x2,x3 are initial conditions (position).
Is func really indepenent of t and x(i)?
The issue with your code is that func will return a row vector, but x(:,1) is intialized as a column vector. Then the right-hand-side defining x(:,2) is column vector plus row vector -- this produces an error.
It is because func seemingly returns a row vector, independent of its inputs size or value, that your code is actually working. Perhaps there is more to func?
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Kye Taylor
Kye Taylor on 15 Aug 2012
You mean U = A\B, not U = A\B'...
Try replacing the x(i) in the for loop with x(i,:)

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