How do I use anonymous functions to pass information between derivate functions for ODE23 ODE45 ODE15s and outputFcn?

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Ken 2013-11-29

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评论： Jan 2013-11-29

I've mastered simple anonymous functions, but I think I'm stretching it too far here. I am trying to record intermediate variables into a data structure SD and save them on every successful step of an ODE routine.

I could, and have in the past, used global variables, but this syntax should be more elegant. Should it work?

function testODE

SD=SteppingData;

SD.iy=0;

SD.Flow=0;

SD.FlowArray=zeros(11,1);

options=odeset('OutputFcn', @(t,y,flag) Stepoutput(t,y,flag,SD));

[t,y]=ode23(@(t,y) equns(t,y,SD),[0 10], 10, options);

SD.FlowArray

end

function dydt=equns(t,y,SD)

SD.Flow=y+2;

dydt=-0.01*y; % first order reaction giving exponential decay

end

function status=Stepoutput(t,y,flag,SD)

% record some intermediate results each step

if ~strcmp(flag,'done')

    SD.iy=SD.iy+1;
    SD.FlowArray(SD.iy)=SD.Flow;
    status=0;

end

And SteppingData.m is:

classdef SteppingData

    properties
    % data to record on each step.  Normally algebraic variables.
        iy;                  % record number
        FlowArray;           % record of flow
        Flow;
    end