Why "Error using odearguments“ and ”Error in ode15s“ ?
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I am trying to solve ODE using ode15s first, when I set some parameters in the subfunction of ODE as constant, I can get the right solution. However, when I set the parameters as variable, and try to use Particle Swarm Optimization（PSO）to fit the parameters, that is to say, to optimize the parameters by fit the results of ODE to experiment datas using PSO, errors always exist like this:
if true
@(T,IN2)ZEROS(0,0) returns a vector of length 0, but the length of initial conditions vector is 30. The vector returned by @(T,IN2)ZEROS(0,0) and the initial conditions vector must have the
same number of elements.
Error in ode15s (line 150)
odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);
Error in PSO (line 43)
[t,N]=ode15s(odefun,[0:95],NN0);
end
The changes in subfunction is like this, first constant and then change to variable.
function A=getA(ii,j,t,R,D)
%UNTITLED9 Collision efficiency
% x1 x2 x3 are fitting parameters
global x1 x2 x3
A=x1*exp(-x2*(1-ii/j).^2)/(ii*j).^(x3);
% A=0.046*exp(-0.1*(1-ii/j).^2)/(ii*j).^(0.1);
end
3 个评论
Walter Roberson
2018-10-5
We need to see your odefun and we need to know more about NN0
Walter Roberson
2018-10-5
Avoid using global.
ZHUEN RUAN
2018-10-5
采纳的回答
Walter Roberson
2018-10-5
In function getA you use
global x1 x2 x3
However, you never assign values to x1, x2, or x3 anywhere in any of your code, so those default to being the empty array, leading getA to return the empty array, so the results of all of your F() calls are the empty array, so you end up trying to process the empty array as an ODE.
You would not have this problem if you were to rewrite your code so that you did not use global.
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