How to change the stop criteria of fsolve?

I have a set of nonlinear equations and I am solving them by fsolve. x(1) to x(6) are my unknowns to be determined and X, Y, Z are definite constants. I wrote the following function:

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function z=equ_set(x)

global X Y Z

z(1)=x(4)-x(5)*x(6)/x(1)-X(1);

z(2)=x(2)-x(6)^2/x(1)-X(2);

z(3)=x(3)-x(5)^2/x(1)-X(3);

z(4)=x(1)-x(6)^2/x(2)-Y(1);

z(5)=x(5)-x(4)*x(6)/x(2)-Y(2);

z(6)=x(3)-x(4)^2/x(2)-Y(3);

z(7)=x(1)-x(5)^2/x(3)-Z(1);

z(8)=x(2)-x(4)^2/x(3)-Z(2);

z(9)=x(6)-x(4)*x(5)/x(3)-Z(3);

end

====== and wrote the followings in command line to solve the eqs. set:

global X Y Z

X=[2/3, 5/3, 2/3];

Y=[5/2, 1/2, 1/2];

Z=[2, 1, 0];

x0=[1,1,1,1,1,1];

fsolve(@equ_set,x0)

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Since fsolve is a numeric solver I used it. How can I change the stop criteria of fsolve? (for example error<1e-3) I have seen "relative norm(grad r)" but I am not sure whether this is the case and how to change it. Thanks

Answer 1

[Matt J]

There is some reading to be done

http://www.mathworks.com/help/optim/ug/tolerances-and-stopping-criteria.html

You can also implement your own stopping criteria using the OutputFcn option

http://www.mathworks.com/help/optim/ug/optimization-options-reference.html#f11022

Answer 2

[Star Strider]

If you want to change the default behaviour of fsolve, use the optimoptions function. See the fsolve Options sections for details on what you can change, the 'MaxFunEvals', 'MaxIter', 'TolFun', and 'TolX' possibly being the most relevant for your purposes.