Hi Misha
1.
define the function to solve with in for instance a separate file
function F=fun1(x,n)
F(1)=x(1)+x(3)-12.54;
F(2)=x(2)+x(4)-12.245;
F(3)= 2*x(1)+n(2)+n(3)-(1493/60);
F(4) =(x(3)*x(2))/(x(1)*x(4))-1000;
2.
if choosing a single lucky start point, then for instance
f1=@fun1
x0=[1 1 1 1];
n=[1 2 1 2];
options = optimoptions('fsolve','Display','none','PlotFcn',@optimplotfirstorderopt);
f2=@(x) f1(x,n)
Y=fsolve(f2,x0)
Y =
2.9951 4.5133 1.6388 0.0025
3.
Not all start points allow fsolve to start, for instance starting x0 all nulls fsolve returns error
x0=[0 0 0 0];
Y=fsolve(f2,x0)
Error using trustnleqn (line 28)
Objective function is returning undefined values at initial point. FSOLVE cannot continue.
Error in fsolve (line 388)
trustnleqn(funfcn,x,verbosity,gradflag,options,defaultopt,f,JAC,...
4.
A way to understand that there are multiple real roots is changing fsolve options to
.
problem.options = optimoptions('fsolve','Display','none','PlotFcn',@optimplotfirstorderopt);
problem.objective = f2;
problem.x0 = [1 1 1 1];
problem.solver = 'fsolve';
Y=fsolve(problem)
grid on
.
.
Misha, if you find this answer useful would you please consider marking my answer as Accepted Answer?
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thanks in advance
John BG
