How to save ode45 outputs in a loop?

I am trying to save my T and Y values in a loop, but it gives me the error "Subscripted assignment dimension mismatch."

I originally had [T,Y] = ode45(dydt, t, [y0, dy0], options); but it would only save when j = 7.

Help please?

for j = 1:7

[T(j),Y(j)] = ode45(dydt, t, [y0, dy0]);

end

Answer 1

[Star Strider]

The easiest way would be to save them as cella rrays, then sort those out later:

for j = 1:7
    [T{j},Y{j}] = ode45(dydt, t, [y0, dy0]);
end

Note the curly brackets {} indicating cell array indexing.

It will be easier to work with them if you define ‘tspan’ as a vector with more than two elements:

t = linspace(0, 5, 50);    % time span

This will result in all the arrays having equal numbers of rows.

Answer 2

[James Tursa]

Don't use a loop. Just call ode45 once and it will give you the entire results in T and Y.

[T,Y] = ode45(dydt, t, [y0, dy0]);

If you want outputs at specific times, set t accordingly. E.g.,

t = linspace(0,5,100);