"Could not find a feasible initial point" error in GA.

Hi everyone

I try to optimize a problem that is visible below:

a1=3.51e9; a2=750.9;
a3=1.93e8; a4=8.10e8;
a5=min(a3,a2); a6=a4-a1;
a7=a1-a5; a8=min(a1,a7);
answer=ga(@(x) 1e-8*((x(1)+x(2)+x(3)+x(4)+x(5))^2)-100*(x(1)+x(2)+x(3)+x(4)+x(5)),5,...
    [-1 0 0 0 0;0 -1 0 0 0;0 0 -1 0 0;0 0 0 -1 0;0 0 0 0 -1;1 0 0 0 0;0 1 0 0 0;...
    0 0 1 0 0;0 0 0 1 0;0 0 0 0 1;-1 -1 -1 -1 -1;1 1 1 1 1],[0 0 0 0 0 1e6 1e7 3e7 5e7 7e7 a6 a8])

but I get this result:

Could not find a feasible initial point.

answer =

     []

what is this error for?

what should I do to solve this issue?

I really appreciate any help.

[Torsten]

We have to know what "a" is.

[Matt J]

Avoid using linear constraints to express simple bounds:

A=[-1 -1 -1 -1 -1;
    1 1 1 1 1];
b=[a6;a8];

lb=zeros(5,1);
ub=[1e6 1e7 3e7 5e7 7e7];

fun=@(x) 1e-8*((x(1)+x(2)+x(3)+x(4)+x(5))^2)-100*(x(1)+x(2)+x(3)+x(4)+x(5));

answer=ga(fun,5,A,b,[],[],lb,ub)

Also consider using quadprog instead. It is better tailored to this type of problem than ga().

[shirin mhd]

dear Torsten

sorry I edited the problem.

dear Matt J

I did changes that you mentioned above but I still get the same error

Answer 1

[Torsten]

The sum of the upper bounds you prescribe for your variables x(1),...,x(5) is smaller than -a6.

But you want to have x(1) + x(2) + x(3) + x(4) + x(5) >= -a6.

Thus it follows from your inequality constraints that the problem has no feasible point.