matrix manipulation for Ps(i)

%%

%please am trying to run this script with the fuction file and input data

%but it keeps giving errors about undefined function and so I need help in

%how I can arrange my C to get Psi in the code file for two components i.e

%z input

%%

function [xeq,yeq,alphaV,fL,fV] = PTFLASH_VLE_NRTL(C, BIP, alpha, P, T, z)

%The funtion PTFLASH_VLE_WILSON calculates VAPOR and LIQUID COMPOSITION,

%VAPOR FRACTION AND LIQUID AND VAPOR FUGACITIES.

%considering deviation from the ideal behavior using WILSON model

%All input/output data are expressed in SI.

%T[K], C[according to equation]

%length of the vector

m=length(z);

%vapor pressure calculation

for i=1:m

Ps(i)=exp(C(i,1)+C(i,2)/T+C(i,3)*log(T)+C(i,4)*T^(C(i,5)));

end

%calling PB and PD equations

[PB, ~] = PB_VLE_NRTL(C, BIP, alpha, T, z);

[PD, x] = PD_VLE_NRTL(C, BIP, alpha, T, z);

if P<=PD

xeq=0;

yeq=z;

alphaV=1;

fL=0;

fV=P*z;

elseif P>=PB

xeq=z;

yeq=0;

alphaV=0;

[gamma,~]=ACTIVITY_NRTL(BIP,alpha,T,xeq);

fL=Ps.*xeq.*gamma;

fV=0;

else

xeq=(x+z)/2; %First guess on x

[gamma,~]=ACTIVITY_NRTL(BIP,alpha,T,xeq); %First guess on gamma

K=(Ps.*gamma)/P; %First guess on K

psi_0=sum(z.*(K-1));

psi_1=sum(z.*(K-1)./K);

if psi_0*psi_1>=0 %Bad initial guess

disp('bad initial guess-BIG PROBLEM')

else %Good initial guess

fL=zeros(1,m);

fV=fL+1;

iter=0;

while max( abs((fV-fL)./fV))>0.00001 && iter<10000 && psi_0*psi_1<0

[ alphaV ] = RACHFORDRICE_BISECT( K,z );

xeq=z./((1-alphaV)+alphaV*K);

yeq=K.*xeq;

[gamma,~]=ACTIVITY_NRTL(BIP,alpha,T,xeq); %Gamma new guess

K=(Ps.*gamma)/P;

psi_0=sum(z.*(K-1));

psi_1=sum(z.*(K-1)./K);

fV=P*yeq;

fL=Ps.*xeq.*gamma;

iter=iter+1;

end

end

end

end

%% Input data

z=[0.1 0.9];

C1=[88.134 153.23];

C2=[-8498.6 -10055];

C3=[-9.0766 -19.488];

C4=[8.330e18 1.6426e5];

C5=[6 2];

RhoL=[803 802];

MW=[60.09 100.16]

MW =

60.0900 100.1600

P=0.5e6;

T=373.15;

BIP=[64.59 538.538];