Index in position 2 exceeds array bounds (must not exceed 1).

%% am encountering difficulty with my codes below and I will be pasting the

%the function file and the input parameters to run them with.

%%

function [gamma,a]=ACTIVITY_WILSON(MW,rhoL,BIP,T,x)

%This program calculates the activity coefficients (gamma) and the

%activities (a) of each component of a mixture of c components using the

%Wilson model.

%INPUT PARAMETERS: MW: vector (1xc) reporting the molecular weights of the

%c components; rhoL, vector (1xc) reporting the liquid density of the c

%pure components at temperature T; BIP is a matrix cxc reporting the energy

%interaction parameters (BIP(i,j)=lambda_ij-lambda_ii, J/mol). The energy

%interaction parameters are temperature independent; T: temperature of the

%system; x vector (1xc) reporting the mole fractions of the components of

%the mixture.

%OUTPUT PARAMETERS: gamma: vector 1xc reporting the activity

%coefficients of the components of the mixture; a: vector 1xc reporting the

%activities of the components of the mixture.

%Unless otherwise stated, all input/output parameters are expressed

%according to MKS.

R=8.314;

c=length(x);

%Molar volumes of the pure liquid components composing the mixture

Vl=1./((rhoL*1000)./MW);

%Lambda terms (dimensionless) of the Wilson formula

for i=1:c

for j=1:c

Lambda(i,j)=(Vl(j)/Vl(i))*exp(-BIP(i,j)/(R*T));

end

end

for i=1:c

for j=1:c

A=sum(x.*Lambda(j,:));

C(j)=x(j)*Lambda(j,i)/A;

end

lngamma(i)=1-log(sum(x.*Lambda(i,:)))-sum(C);

gamma(i)=exp(lngamma(i));

a(i)=gamma(i)*x(i);

end

end

%%

x= Varying from 0 to 1;

MW=[46.0684 18.0153];

rhoL=[785 997];

BIP=[1972.2 ; 3700.1];

%%

Please help me find what am doing wrong . thank you but please comment if there is something am doing wrong with the way i ask because I never got replies before now.

[KALYAN ACHARJYA]

How to format the question, read here? Well formatting question get answer quickly.

Answer 1

[KALYAN ACHARJYA]

Save the following function file>Save as : ACTIVITY_WILSON.m file name

function [gamma,a]=ACTIVITY_WILSON(MW,rhoL,BIP,T,x)
R=8.314;
c=length(x);
%Molar volumes of the pure liquid components composing the mixture
Vl=1./((rhoL*1000)./MW);
%Lambda terms (dimensionless) of the Wilson formula
for i=1:c
    for j=1:c
        Lambda(i,j)=(Vl(j)/Vl(i))*exp(-BIP(i,j)/(R*T));
    end
end
for i=1:c
    for j=1:c
        A=sum(x.*Lambda(j,:));
        C(j)=x(j)*Lambda(j,i)/A;
    end
    lngamma(i)=1-log(sum(x.*Lambda(i,:)))-sum(C);
    gamma(i)=exp(lngamma(i));
    a(i)=gamma(i)*x(i);
end
end

Now call the above function from different Matlab scripts file:

%%
x=0.2; % Any value 0 to 1
MW=[46.0684 18.0153];
rhoL=[785 997];
BIP=[1972.2; 3700.1];
T=30; % Hopefully this is tempature, set accordingly
[gamma,a]=ACTIVITY_WILSON(MW,rhoL,BIP,T,x)

Result

 gamma =
     1.358311135425136e+04
a =
     2.716622270850272e+03

Suggested: To undestand function call, read here

[Chinaemerem Valentine Nwobi]

Thank you so much Kalyan.