Problem With GA toolbox?

i have a problem.. i have a function to minimize..

say F(x)=x(1)^4.5+x(2)/x(3)+x(4)*100+x(5)

the values of the decision variables lie between 1 and 24. And they should only be from this set [1 2 4 8 16 18 22 24]..

Answer 1

[Alan Weiss]

If you have MATLAB R2011b or later, and Global Optimization Toolbox, you can solve this kind of problem using the GA function. See this section of the documentation for information on integer optimization, and this example to see how to convert integer constraints to constraints involving choosing from a particular set of values.

Good luck,

Alan Weiss

MATLAB mathematical toolbox documentation

[Mesanlibor]

greeting.. thank you for the answer. but i am using matlab R2008b.. can u giveme any other idea on how to proceed wit this

[Alan Weiss]

You can try using the ideas in this technical support answer.

Good luck,

Alan Weiss

MATLAB mathematical toolbox documentation

Answer 2

[Juan Camilo Medina]

You don't need to solve this numerically. The arguments that minimize the equation are the values that minimize each term in the equation, which are the lowers value in your set (except the second term):

argmin x(1)^4.5=1
argmin x(2)/x(3)=1/24 (since x(3) is divining then you want the largest value)
argmin x(4)*100=1
argmin x(5)=1

therefore:

x_optimum= [1 1 24 1 1], f_optimum=(1+1/24+1+1)=73/24.