fmincon contraints range issue

Hello everyone,

In case i need the surface ares as written in the constraint(c=area_surf(x)-10). In case i want to be between 10 and 5, I have tried to add & conditio but there was an error.

how should i write it?

Thanks in advance

Ayman

unction y = fcn(x)
% L_G=1;
% W_G=1;
% H_G=1;
% X0=[ L_G  W_G H_G 5 6 ]
  X0=[x];
xopt=fmincon(@objective,X0,[],[],[],[],[],[],@contraints)
v=calcvolume(xopt)
a=area_surf(xopt)
function volume= calcvolume(x)
 L=x(1);
 W=x(2);
 H=x(3);
 
 volume= L*W*H
end 
function surface= area_surf(x)
 L=x(1);
 W=x(2);
 H=x(3);
surface = 2*L*H + 2*L*W + 2*W*H;
end
function obj =objective(x)
obj=-calcvolume(x)
end
function [c, ceq]= contraints(x)
c=area_surf(x)-10
ceq=[];
end

Answer 1

[Alan Weiss]

You simply need two constraints, area_surf < 10 and area_surf > 5.

function [c, ceq]= contraints(x)
c(2) = area_surf(x) - 10;
c(1) = 5 - area_surf(x);
ceq = [];
end

Alan Weiss

MATLAB mathematical toolbox documentation