Limiting "y" output of ODE solvers

Question

David H 2016-4-29

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/281688-limiting-y-output-of-ode-solvers

编辑： David H 2016-4-29

I am currently running an ODE solver in the form

   dy = @(t,y) M*y;
    [tout,y_out] = ode45(dy, trange,yinit);
% y_out is a length(trange) by length(yinit) matrix
  range_needed = [1:10,100:105]; %for example
    y_needed = y_out(:,range_needed);

Essentially I only actually "want" a section of y_out but doing it this way fills lots of the memory with values I don't actually need. Edit: To clarify I want all the time values in trange not some limited value, what I want to limit in the output is the size in the other direction, let us call it the "spatial" direction.

I could use an output function to process the ODE output and only select this bit but the one I have written isn't very good. Is there any way to do what I can do this the ode45 options? Failing that is there a function anyone knows that does this on the FEX?