Initial Step ODE45 not working
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I am using an ode45 with options but my time vector still doesn't have the 1st step as I defined. I should have t=[0 5 15 25 35...] But I have t=[0 10 20 30...]
tspan=[1 10000]
options = odeset('NormControl','on','RelTol',simul.RelTol,'AbsTol',simul.AbsTol,'InitialStep',5,'Refine',1,'stats','off','MaxStep',MaxStp,'OutputFcn',@IntegrationFcn);
[ t , y ] = ode45( @dy , tspan , y_0 , options );
2 个评论
madhan ravi
2018-10-21
编辑：madhan ravi
2018-10-21
Upload your code for dy
Francesco Fortunato
2018-10-21
采纳的回答
Walter Roberson
2018-10-21
1 个投票
When you pass in a tspan that has two elements then ode45 will automatically pick times to evaluate at as needed to maintain accuracy.
You can pass a vector of times instead. ode45 will output for those times. It will continue to evaluate at whichever points it wants to maintain accuracy, but it will calculate for the times given and report only for those.
2 个评论
Francesco Fortunato
2018-10-21
Walter Roberson
2018-10-21
Right. But you would want tspan starting from zero in most conditions, as the first element of tspan tells it the time at which the boundary conditions apply. So for example,
tspan = [0 5 10:10:10000];
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