# How to save ode45 outputs in a loop?

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EB 2019-10-9

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

### 采纳的回答

Star Strider 2019-10-9
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.

### 更多回答（1 个）

James Tursa 2019-10-9

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);

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