Writing For loop for summation of B in Matlab

Question

the summation to be written in a for loop is here

 TCPC = csvread ( 'tcpc.csv' ) ; 
 TCPC ( : , 3) = TCPC ( : , 3 ) * (100000); %unit conversion 
 TCPC ( : , 5) = TCPC ( : , 5 ) * (1e-6); %unit conversion 
 %------------------------------------------------------------------------ 
 % Within the outer loop we calculate Bii's Psat for all components 
 for i = 1 : n 
 
W(i,i)  = TCPC (SP(i),1) ; 
TC(i,i) = TCPC (SP(i),2); 
PC(i,i) = TCPC (SP(i),3);
ZC(i,i) = TCPC (SP(i),4);
VC(i,i) = TCPC (SP(i),5);
TR(i,i) = T/TC(i,i);
Bi(i,i)  = (R*TC(i,i)/PC(i,i))*((.083-(.422/(TR(i,i)^(1.6))))+(W(i,i)*(.139- 
((.0172/(TR(i,i)^4.2)))))); 


    phisat(i) = exp((Bi(i,i)*P)/(R*T)) ;  
 
    for j = i+1 : n % Within the inner loop we calculate Bij's (mixed coefficients) 

    W(i,j) = (TCPC (SP(i),1) + TCPC (SP(j),1)) / 2 ; 
    TC(i,j) = sqrt((TCPC (SP(i),2) * (TCPC (SP(j),2)))) ; 
    ZC(i,j) = ((TCPC (SP(i),4) * (TCPC (SP(j),4))))/2 ;
    VC(i,j) = (((TCPC (SP(i),5)^(1/3) * (TCPC (SP(j),5)^(1/3))))/2)^(3) ;
    PC(i,j) = ((ZC(i,j) * R * (TC(i,j)))/VC(i,j)) ;
    Bi(i,j) = ((R*TC(i,j))/PC(i,j))*((.083-(.422/(TR(i,i)^(1.6))))+(W(i,j)*(.139- 
    ((.0172/(TR(i,i)^4.2))))));

    Bi(j,i)=Bi(i,j); % as Bij=Bji we write the inner loop for j = i+1 : n and assigned 
the values to rest 

end 
end 

for i = 1 : n
B(i,i) = ((X(i))^2)*Bi(i,i);
a = sum(B(i,i));
for j = i+1 : n
    B(i,j) = X(i)*X(j)*Bi(i,j);
    B(j,i) = B(i,j);
    b = sum(B(i,j)); c = sum(B(j,I));
  end

end
Bfinal = a+b+c

%------------------------------------------------------------------------ % Having calculated all the second virial coefficients,
% we calculate the fugacity coefficients for all the components of the mixture % use phi bar 1-3 and phi 1-3 for i = 1:n for j = i+1 : n phi(i,j) = exp((((-Bfinal+2*X(i)Bi(i) + 2X(j)))P)/(RT)); end end