How to access the current iteration number in the program where we supply the non-linear equations,F =0 and the Jacobian for FSOLVE?
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Rahul Gulati
el 15 de Sept. de 2020
Comentada: Ameer Hamza
el 15 de Sept. de 2020
For example, in the sample code for fsolve:
fun = @root2d;
x0 = [0,0];
x = fsolve(fun,x0)
where :
function F = root2d(x)
current_iteration= ?
F(1) = exp(-exp(-(x(1)+x(2)))) - x(2)*(1+x(1)^2);
F(2) = x(1)*cos(x(2)) + x(2)*sin(x(1)) - 0.5;
In the code root2d, if my non linear problem formulation depends on the current iteration, how can i access the present iteration number?
I understand that once all the iterations have been completed, we can get the total number of iterations for convergence using 'output paramter' but this is not what i want.
2 comentarios
Ameer Hamza
el 15 de Sept. de 2020
Can you show an example of where this might be relevant? The problem definition is usually independent of the algorithm. Different algorithms will take a different number of iterations to reach the same optimal solution. How can you use the iteration number in the equations in any useful way?
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Ameer Hamza
el 15 de Sept. de 2020
Editada: Ameer Hamza
el 15 de Sept. de 2020
Something like this will work
global iter_number % global variable for a quick example, i recommend creating a handle class object
iter_number = 0;
fun = @root2d;
x0 = [0,0];
opts = optimoptions('fsolve', 'OutputFcn', @outputFcn);
x = fsolve(fun,x0, opts);
root2d(x)
function F = root2d(x)
global iter_number
current_iteration = iter_number
F(1) = exp(-exp(-(x(1)+x(2)))) - x(2)*(1+x(1)^2);
F(2) = x(1)*cos(x(2)) + x(2)*sin(x(1)) - 0.5;
end
function stop = outputFcn(x, optimValues, state)
global iter_number
iter_number = optimValues.iteration;
stop = 0;
end
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