how to select values of alpha beta and gamma values in firefly algorithm

hi

i hope everyone is fit and fine. i am writing a matlab program in which i have to bring three variable on to particular target. for that i use firefly algorithm. here three variables (p1,p2,p3) are taken and there values are (10,15,20) and at the end of iteration all will be (50,50,50), but unfortunately the response which is desired is not obtain. i think the issues is of the proper selection of alpha beta and gamma. can any body help me in this regard i will be highly thankful

Regards Mudasir

clc
clear

p1=10;
p2=15;
p3=20;
t=50;

b0=1;

gamab=1;     %initial
gamae=1.1;     %final

alphab=0.5
alphae=0.3

for i=1:1000

    d1=t-p1;
    r1=sqrt((d1)^2);

    d2=t-p2;
    r2=sqrt((d2)^2);

    d3=t-p3;
    r3=sqrt((d3)^2);

    gama=gamab+((gamae-gamab)*i)/50;
    alpha=alphab+((alphae-alphab)*i)/50;

    c=gama^r1;
    b1=b0*exp(-c)

    d=gama^r2;
    b2=b0*exp(-d)

    e=gama^r3;
    b3=b0*exp(-e)

    A=[b1 b2 b3];
    B=[p1 p2 p3];
    J=max(A)

    [m1 n1]=size(B);
    for y=1:n1
        if A(1,y)== J;
            gbestx=B(1,y)
        else
        end
    end

    p1=p1+(b1*(gbestx-p1))+alpha*(rand-0.5)

    p2=p2+(b2*(gbestx-p2))+alpha*(rand-0.5)

    p3=p3+(b3*(gbestx-p3))+alpha*(rand-0.5)

end