for loop not working in fixed point iteration while loop

I donot know how to solve this problem

after 1st of iteration I got this error in to for loop.

the code attached with its variables

clc
clear all
load('results.mat')
N_pr = 99;
P_sat = Pb;
P_abandon = 1700;
delh_pr = (P_sat-P_abandon)/N_pr;
for pr=1:N_pr+1
    Pavg_pr(pr)=P_abandon+(pr-1)*delh_pr;
end
Pavg_pr = sort(Pavg_pr,'descend');
Pavg_pr=Pavg_pr';
%--------------------------------------------------
Vpi = (W*Bwi + N*Boi)*(cf*(p0-P_sat));
%--------------------------------------------------
%Interpolate PVT data @ P_sat & Pavg_pr
%--------PVT @ P_sat-----------
Boi = pchip(P_o,Bo,5200);
Bo_Pb = pchip(P_o,Bo,P_sat);
Bg_Pb = pchip(P_g,Bg,P_sat);
muo_Pb=pchip(P_o,mu_o,P_sat);
mug_Pb=pchip(P_g,mu_g,P_sat);
Rs_Pb = pchip(P_o,Rs,P_sat);
Rv_Pb=pchip(P_g,Rv,P_sat);
%---------- PVT @ Pavg_pr-------
Bo_pr = pchip(P_o,Bo,Pavg_pr);
Bg_pr = pchip(P_g,Bg,Pavg_pr);
muo_pr=pchip(P_o,mu_o,Pavg_pr);
mug_pr=pchip(P_g,mu_g,Pavg_pr);
Rs_pr = pchip(P_o,Rs,Pavg_pr);
Rv_pr=pchip(P_g,Rv,Pavg_pr);
%--------------------------------------------------------------------
%calculate Np @ P_sat %Ignored Vpi
Np_sat = ((N*(Bo_Pb-Boi))+Vpi)/Bo_Pb;
%--------------------------------------------------------------------
%calculate Bto , Xn , Xg , Fn &	Fg    %Ignored Vpi in Fn & Fg
Bto_pr = (Bo_pr.*(1-Rv_pr.*Rs_Pb)+Bg_pr.*(Rs_Pb-Rs_pr))./(1-Rs_pr.*Rv_pr);
Xn = (Bo_pr-(Bg_pr.*Rs_pr))./(1-(Rv_pr.*Rs_pr));
Xg = (Bg_pr-(Bo_pr.*Rv_pr))./(1-(Rv_pr.*Rs_pr));
Fn = Xn./(Bto_pr-Bo_Pb);
Fg = Xg./(Bto_pr-Bo_Pb);
%-----------------------------------------------------------------------
dNp=zeros(length(Pavg_pr),1);
dGp =zeros(length(Pavg_pr),1);
Np_cum=zeros(length(Pavg_pr),1);
Gp_cum = zeros(length(Pavg_pr),1);
Rp_guess = 10;
dNp(1)=Np_sat;
dGp(1)=Np_sat*Rp_guess;
Np_cum(1)=dNp(1);
Gp_cum(1) =dGp(1);
Error = 100;
iterationss=0;
while Error > 0.5E-3
%--------------------------------------
%Calculate dNp , dGp , cum Np , cum Gp
   for y =2:length(Pavg_pr)
     dNp(y)=((N-Np_cum(y-1)*Fn(y))-(Gp_cum(y-1)*Fg(y)))/...
            (Fn(y)+(Rp_guess*Fg(y)));
     dGp(y)=dNp(y)*Rp_guess;
     Np_cum(y) =dNp(y)+ Np_cum(y-1);
     Gp_cum(y) = dGp(y)+Gp_cum(y-1);
   end
       %Np_cum =cumsum(dNp);
       %Gp_cum = cumsum(dGp);
%--------------------------------------
%Calculate Saturations and Relative Permeabilities
%Sg_pr , Krg_pr , So_pr , Kro_pr
    Wps=W;
    Bw_pr=Bwi;
    Sg_pr = Bg_pr.*((G-Gp_cum)-(N-Np_cum).*Rs_pr)./((W-Wps).*Bw_pr.*(1-Rs_pr.*Rv_pr)+(G-Gp_cum).*(Bg_pr-Rv_pr.*Bo_pr)+(N-Np_cum).*(Bo_pr-Rs_pr.*Bg_pr));
    So_pr = Bo_pr.*((N-Np_cum)-(G-Gp_cum).*Rv_pr)./((W-Wps).*Bw_pr.*(1-Rs_pr.*Rv_pr)+(G-Gp_cum).*(Bg_pr-Rv_pr.*Bo_pr)+(N-Np_cum).*(Bo_pr-Rs_pr.*Bg_pr));
    Krg_pr = pchip(SoT,KrgT,So_pr);
    Kro_pr = pchip(SoT,KroT,So_pr);
%-------------------------------------
%Calculate Rp_new
           Rp_new = ((Krg_pr./(mug_pr.*Bg_pr))+((Kro_pr.*Rs_pr)/(muo_pr.*Bo_pr)))./...
                    ((Kro_pr./(muo_pr.*Bo_pr))+((Krg_pr.*Rv_pr)/(mug_pr.*Bg_pr)));
 Error = abs(Rp_guess-Rp_new);
 Rp_guess = Rp_new;
 iterationss=iterationss+1;
 clc
 Error;

end

[KSSV]

Variable Rp_guess is matrix of size 100x100. This is the reason for error.

Replace this line:

dNp(y)=((N-Np_cum(y-1)*Fn(y))-(Gp_cum(y-1)*Fg(y)))/(Fn(y)+(Rp_guess*Fg(y)));

with:

dNp(:,:,y)=((N-Np_cum(y-1)*Fn(y))-(Gp_cum(y-1)*Fg(y)))./(Fn(y)+(Rp_guess*Fg(y)));

[Hazem Mohamed]

why Rp_guess matrix of size 100x100?

[Hazem Mohamed]

after replaced this line of code, it gave another error message

Unable to perform assignment because

the size of the left side is 100-by-1

and the size of the right side is

100-by-100.

Error in Prediction (line 60)

dNp(:,:,y)=((N-Np_cum(y-1)*Fn(y))-(Gp_cum(y-1)*Fg(y)))./(Fn(y)+(Rp_guess*Fg(

[KSSV]

dNP will be of size 100x100 becuase Rp_guess is 100x100. You need to initialize dNP before loop.

[Hazem Mohamed]

I already initialize dNP before loop

dNp=zeros(length(Pavg_pr),1);

dGp =zeros(length(Pavg_pr),1);

Np_cum=zeros(length(Pavg_pr),1);

Gp_cum = zeros(length(Pavg_pr),1);

[KALYAN ACHARJYA]

Based on the information you provided, there is an error that is directly visible. The variable Rp_guess is initially defined as a scalar value, but later in the code, it is replaced by Rp_new, which is a 100x100 matrix.

To address this issue, you can modify the code as follows:

1. Declare dNp as a cell array to accommodate the 100x100 data:

dNp = cell(100, 100); 

Alternatively, ensure that only scalar values are returned by the following statements (after exiting the loop).

((N-Np_cum(y-1)*Fn(y))-(Gp_cum(y-1)*Fg(y)))/...
            (Fn(y)+(Rp_guess*Fg(y)));

2. Replace the calculation statement with an appropriate loop to generate the 100x100 data and store it in the dNp cell array:

dNp(y)=((N-Np_cum(y-1)*Fn(y))-(Gp_cum(y-1)*Fg(y)))/...
            (Fn(y)+(Rp_guess*Fg(y)));

By making these modifications, you can generate the 100x100 data using element-wise division (./) and store it in the dNp cell array.

Please note that I assumed you wanted to replace Rp_guess with Rp_new. If there are additional details or specific requirements, please provide them, and I'll be happy to assist you further.