Unknown parameters in ode

I am trying to solve an ode with an unknown parameter. I am not sure If I am doing it in the right way. 'Not enough input arguments'
tol = 10^-3; % Treshold
MAX = 100;
H = 0;
interval = [0.01 0.2]; % alpha interval
a = interval(1);
b = interval(2);
alpha = (a+b)/2;
v0=[1 0.01 1];
[z,v]=ode45(@rhs,interval,v0,alpha);
iter = 1;
while(abs((v(end, 2)) - H) > tol)
alpha= (a + b)/2;
[z,v]=ode45(@rhs,zspan,v0,alpha);
end
if(v(end, 2) - H > 0)
b = alpha;
else
a = alpha;
end
iter = iter + 1;
if(iter > MAX)
return;
end
function parameters=rhs(z,v,alpha)
da= 2*alpha-(v(1).*v(3))./(2*v(2).^2);
db= (v(3)./v(2))-(2*alpha*v(2)./v(1));
dc= -(2*alpha*v(3)./v(1));
parameters=[da;db;dc];
end

 采纳的回答

Walter Roberson
Walter Roberson 2018-4-7

0 个投票

4 个评论

Hi Walter, The document in the link has no helpful info for the purpose of my case.
That page describes how you can pass the variable alpha defined in your script into the rhs function whose function handle you pass into ode45.
[z,v]=ode45(@(z,v)rhs(z,v,alpha),zspan,v0);
Notice that @(z,v)rhs(z,v,alpha) is an example of parameterizing a function just like is described in the link.
I see it now. The code works as well as intended. Thanks a lot!!

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