Code unable to reconcile vector assignment - matlab

Question

I am interested in modifying the code below to find the parameters I_1, I_2, I_3 and I_4, to be used in another code. Every time I run the code, it throws up
In an assignment A(:) = B, the number of elements in A and B must be the same
on this line " mult(mult == 0) = B;".
I have spent eternity figuring out what the problem could be. Here is the code:
%%% Some Parameters %%
delta = 0.6; % Blanked subframe ratio
B = [0 0.2 0.4 0.6 0.8 1]; %Power splitting factor
k = 2.3; %Macro BS density
f = k*5; %Small cell density
j = 300; %users density
P_m = 46; %Macro BS transmission power
P_s = 23; %SC transmit power
Zm = -15;
Zs = -15;
iter = 30; %Iteration run
h = 500; %Simulation area
hu = 0.8*h; %users simulation area
Vm = round(k*h); %Macro BS average no in h
Vs = round(f*h); %SC average no in h
Vu = round(j*hu); %%users average no in hu
Pm = 10^(P_m/10)/1000*10^(Zm/10);
Ps = 10^(P_s/10)/1000*10^(Zs/10);
for i = iter;
%% XY coodinates for Macrocell, small cells and users.
Xm = sqrt(h)*(rand(Vm,1)-0.5);
Ym = sqrt(h)*(rand(Vm,1)-0.5);
Xs = sqrt(h)*(rand(Vs,1)-0.5);
Ys = sqrt(h)*(rand(Vs,1)-0.5);
Xu = sqrt(hu)*(rand(Vu,1)-0.5);
Yu = sqrt(hu)*(rand(Vu,1)-0.5);
%Total coordinates for MBS and small cells
Total_Coord = [Xs Ys ones(size(Xs)) Xm Ym 2*ones(size(Xm))];
%Distance between BSs and users
[Xsm_mat, Xu_mat] = meshgrid(Total_Coord(:,1),Xu);
[Ysm_mat, Yu_mat] = meshgrid(Total_Coord(:,2),Yu);
Distance = sqrt((Xsm_mat-Xu_mat).^2 + (Ysm_mat-Yu_mat).^2);
%% To determine serving BS for each user
[D_m,idx_m] = min(Distance(:,(length(Xs)+1):end),[],2);
idx_m = idx_m + length(Xs);
[D_s,idx_s] = min(Distance(:,1:length(Xs)),[],2);
%% Power received by users from each BS
Psm_mat = [Ps*ones(length(Xu),length(Xs))
Pm*ones(length(Xu),length(Xm))]; % Transmit power of MBS and small cells
Pr_n = Psm_mat.*exprnd(1,size(Psm_mat))./(Distance*1e3).^4;
mult = binornd(1,delta,1,length(Xm)); % Full transmission power of each
interfering MBS for delta
mult(mult == 0) = B; % Reduced transmission power for (1-delta)
Pr = Pr_n.*[ones(length(Xu),length(Xs)) repmat(mult,length(Xu),1)];%
Interference from each BS
%% Power received by each user from serving BSs
Prm = Pr(sub2ind(size(Pr),(1:length(idx_m))',idx_m));
Prs = Pr(sub2ind(size(Pr),(1:length(idx_s))',idx_s));
P_m_n = Pr_n(sub2ind(size(Pr_n),(1:length(idx_m))',idx_m));
%% Total interference for each UE
I_T = sum(Pr,2) - Prm - Prs;
I_1 = P_m_n./(Prs + I_T);
I_2 = Prs./(P_m_n + I_T);
I_3 = B*I_1;
I_4 = Prs./(B*P_m_n + I_T);
end
The error appeared on this line "mult(mult == 0) = B;".
I know it to be assignment problem which requires equality in both the left and right dimensions. Suggestions for correction will be appreciated.

Answer 1

Your vector mult has length Vm (number of macro BS?). Assigning to mult(mult==0) will assign to a subset of this vector (those that have a value equal to zero). What you are assigning is your variable B which you define as B = [0 0.2 0.4 0.6 0.8 1], i.e., it is a length-6 vector. The assignment fails unless mult has exactly 6 zeros.
I highly doubt that this is what you want. It looks like you are trying to assign the same value ("Reduced transmission power"). Then your B should be scalar though.
Since we have no idea what you are trying to do (and your code is not exactly an MCVE), we can only guess.