error in minimize function

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Mohammad 2015-6-16

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评论： Matt J 2015-6-17

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Hi I want to calculate minimum of this function but when I using nonlinear constrain, i have this error

x=fmincon(fx,[1,1],[],[],[],[],[1 0.99],[1 1.1],@confun)

No feasible solution found.

fmincon stopped because the size of the current step is less than the default value of the step size tolerance but constraints are not satisfied to within the default value of the constraint tolerance.

 x =
   1.000000000000000   1.099999986802130

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Mohammad 2015-6-17

编辑：Mohammad 2015-6-17

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yes I want the first element be 1. my function is :

 f=@(G,r)abs((G*r)/4 + ((G^2*r^2)/16 + (G*r)/4 - 1/4)^(1/2) + 1/2) + abs((2004*G + 200*G*r + 1001*G^2*r + 200)/(6006*G + 600) - ((1003*G + 200*G*r + G^2*r)/(6006*G + 600) - (2004*G + 200*G*r + 1001*G^2*r + 200)^2/(9*(2002*G + 200)^2))/(((G/(4004*G + 400) + (2004*G + 200*G*r + 1001*G^2*r + 200)^3/(27*(2002*G + 200)^3) - ((1003*G + 200*G*r + G^2*r)*(2004*G + 200*G*r + 1001*G^2*r + 200))/(6*(2002*G + 200)^2))^2 + ((1003*G + 200*G*r + G^2*r)/(6006*G + 600) - (2004*G + 200*G*r + 1001*G^2*r + 200)^2/(9*(2002*G + 200)^2))^3)^(1/2) + G/(4004*G + 400) + (2004*G + 200*G*r + 1001*G^2*r + 200)^3/(27*(2002*G + 200)^3) - ((1003*G + 200*G*r + G^2*r)*(2004*G + 200*G*r + 1001*G^2*r + 200))/(6*(2002*G + 200)^2))^(1/3) + (((G/(4004*G + 400) + (2004*G + 200*G*r + 1001*G^2*r + 200)^3/(27*(2002*G + 200)^3) - ((1003*G + 200*G*r + G^2*r)*(2004*G + 200*G*r + 1001*G^2*r + 200))/(6*(2002*G + 200)^2))^2 + ((1003*G + 200*G*r + G^2*r)/(6006*G + 600) - (2004*G + 200*G*r + 1001*G^2*r + 200)^2/(9*(2002*G + 200)^2))^3)^(1/2) + G/(4004*G + 400) + (2004*G + 200*G*r + 1001*G^2*r + 200)^3/(27*(2002*G + 200)^3) - ((1003*G + 200*G*r + G^2*r)*(2004*G + 200*G*r + 1001*G^2*r + 200))/(6*(2002*G + 200)^2))^(1/3));
>> fx=@(x)f(x(1),x(2));

Also my Confun, which saves as mfile is:

 function [c, ceq] = confun(x)
% Nonlinear inequality constraints
c = [(x(1)*x(2))-1];
% Nonlinear equality constraints
ceq = [];

this constrain says that G<(1/r) but when I say the answer which give me matlab, these constrain have been ignored.

Mohammad 2015-6-17

for simplification the problem i said this actually G and r is not constant

Matt J 2015-6-17

But what happens when you do it?

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