A very simple question for GA

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Nagh Meh
Nagh Meh 2012-6-27
Dear all, I have a very simple question as follows, I just want to clarify if I am doing right or not:
I have a function named: function [wRemAlo] = Resource allocation (x)
x: have three possible values which I am entering in command line before running the function e.g. I put "x = [90,20,0,10]" and
After receiving the input values of x, my function allocate resources to 16 variables v (v(1) to v(16)) and return the single variable of "wRemAlo".
I want ga to minimise the output of the function: "wRemAlo"
My function is working correct and return the correct value for "wRemAlo" whenever I run it.
I put constraints as follows to put restrictions on ga decisions and pass the handle for the function to ga solver as follows:
ObjectiveFunction = @ResourceAllocation;
nvars = 16; A=[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 ; 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ; 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0 ; 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0 ; 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1 ; 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0 ; 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0 ; 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0 ; 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1 ];
b=[105;90;20;0;10;0;0;45;60]; LB = [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0];
[v,fval] = ga(ObjectiveFunction,nvars,A,b,[],[],LB,[],[])
The fval value returns after running ga dose not make any sense! Should this value be as same as the value for the function output: "wRemAlo"
Please somebody tell me if I am doing correct or not??
regs, Melody

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采纳的回答

Seth DeLand
Seth DeLand 2012-6-27
It looks like there is an issue with the way your decision variables are defined. The input to the objective function (which is currently x), should be a vector of the decision variables. If the v's are your decision variables that you want to optimize, then the objective function should look like
[wRemAlo] = ResourceAllocation(v)
If you also need to use the values in x inside ResourceAllocation, there's an example here that shows how to pass additional arguments (in the minimizing using additional arguments section).

更多回答（1 个）

Nagh Meh
Nagh Meh 2012-6-27
Thanks a lot Seth,
I changed it to followings:
==================================== w1 = 0; w2 = 0; w3 = 45; w4 = 60;
x1 = 90; x2 = 20; x3 = 0; x4 = 10;
ObjectiveFunction = @(v) ResourceAllocation (v,x1,x2,x3,x4,w1,w2,w3,w4);
nvars = 16; A=[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 ;
1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ;
0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0 ;
0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0 ;
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1 ;
1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0 ;
0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0 ;
0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0 ;
0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1 ];
b=[w1+w2+w3+w4;x1;x2;x3;x4;w1;w2;w3;w4]; LB = [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0];
[v,fval] = ga(ObjectiveFunction,nvars,A,b,[],[],LB,[],[]) ====================================
I also need to clarify one thing:
In my fitness function:
[wRemAlo] = ResourceAllocation(v,x1,x2,x3,x4,w1,w2,w3,w4)
v(1), v(2), ..... v(16) are my decision variables that I want ga to find the best values for them with which "wRemAlo" would be minimised.
In my fitness function, I calculate the values for v through loops and fors and I assigned the calcuted value at the end of the function to v(1) to v(16) e.g. :
v(1) = H1_all_w1; v(2) = H1_all_w2; v(3) = H1_all_w3; . . . . .
With which I have mentioned how the values for all v() s will be calculated through the function.
and when I call the function from the CL:
[v] = ResourceAllocation(v,x1,x2,x3,x4,w1,w2,w3,w4)
the values for vs are:
Columns 1 through 9
0 0 15 20 0 0 15 5 0
Columns 10 through 16
0 0 0 0 0 10 0
I would like to know, am I doing correct or I do not need to assign the values for vs inside the pure function as it may give me the wrong answers?
regs, M.

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