The following code works perfectly, when I omit while loop. However I get infinite loop when 'while' loop included. My goal is obtaining 4x1 matrix for GF1, whose values shall be within 5% of number 1

T=[0 20 30 15; 20 0 10 40; 30 10 0 35; 15 40 35 0]; 
G = [130 140 225 90]'; 

GF1= G./sum(T,2); 

while max([abs(GF1-1)]) > 0.05 % iteration process for growth factor to be within +/- 5% of 1

for a=1:4
        x(a,:)=T(a,:)*GF1; %denominator
        y(a,:)=T(a,:)*GF1(a)*Rowsum(a);

end
X1=repmat(x,1,4);
z=repmat(GF1',4,1);
y1=y.*z;
V=y1./X1; 

K=zeros(4); 
for m=1:4;
    for n= 1:4;
    K(m,n) = (V(m,n)+ V(n,m))*.5;
    end
    end
T = K; 
GF1= G./sum(T,2) 

end

[Walter Roberson]

Note: your section of code

K=zeros(4); 
for m=1:4;
    for n= 1:4;
    K(m,n) = (V(m,n)+ V(n,m))*.5;
    end
    end
T = K;

could be written as

T = (V + V')/2;