I'm trying to solve a system of non linear odes in Matlab as follows.

editparams %parameters
Tend = 50;
Nt = 100;
% Define RHS functions
RHS = @(t,x) ModelRHS(t,x,param); %anonymous function defining the set of equations
%Execution-----------------------------------------------------------------
x0 =[0.04;0.75;0.85]; %Initial condition
t = linspace(0,Tend,Nt); %TSPAN
[t x] = ode45(RHS, t, x0);

Now, I need to find the steady state of the system and I'm trying to create a function for this. I thought I'd calculate the steady state using the Jacobian. My equations are in an anonymous function which is defined as f in the code below. However, I realised that jacobian does not work for anonymous functions (or may be there is a way to do with anonymous functions) . so I thought I would convert the anonymous function to a symbolic function and try it. But i still have a difficulty in getting that done. So any help is really appreciated!

function SS = SteadyState(param, E)
f = @(t,x)ModelRHS(t,x,param,E); %set of odes
SymbolicSystem = sym(f); %trying to make the anonymous function symbolic
SymbolicJacobian = jacobian(SymbolicSystem',x); %jacobian
Jacob = matlabFunction(SymbolicJacobian,x);
end

Also if there is any other way apart from finding the Jacobian, kindly let me know about that too. I tried using 'fsolve' to calculate the steady-state as follows:

f = @(t,x)ModelRHS(t,x,param);
x0 =[0.04;0.75;0.85]';
options = optimoptions('fsolve','Display','iter'); % Option to display output
SS = fsolve(f,x0,options); % Call solver

but it returned an error

 Not enough input arguments.
Error in @(t,x)ModelRHS(t,x,param)
Error in fsolve (line 242) fuser = feval(funfcn{3},x,varargin{:});
Caused by: Failure in initial objective function evaluation. FSOLVE cannot continue.

2 Sorted by: Reset to default

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