Matrix assignment inequality problem

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

[Bruno Luong]

Just shooting in the dark, try replace the problematic instruction with

mult(mult == 0) = B(mult == 0);

[Saint Dee]

Thanks Bruno. On replacing with the suggestion, it threw in "Index exceeds matrix dimension" on the same line.

[Bruno Luong]

Type in command line

>> dbstop if error

Run the code, when error occurs, get the size of mult

>> size(mult)
>> size(B)

Then report the results

[Saint Dee]

When I pressed run, it opened a 'meshgrid.m' window and the following error..

Error using repmat Out of memory. Type HELP MEMORY for your options.

Error in meshgrid (line 59)

        yy = repmat(ycol,size(xrow));

Error in Untitled5 (line 38)

       [Xsm_mat, Xu_mat] = meshgrid(Total_Coord(:,1),Xu);

Further running size(mult) and size(B), the following error popped up for both..

Undefined function or variable 'mult'.

Undefined function or variable 'B'.

59 yy = repmat(ycol,size(xrow));

I have never encountered this error since I've been running the code. My recurrent error had been on the 'mult' line until @madhan identified another error in the dimensions of Xs and Xm. I'm totally derailed.

[Bruno Luong]

Then it becomes too messy for me to guide you, sorry.

[Bruno Luong]

Actually I reeread the code and this statement

mult(mult == 0) = B

doesn't look at all right. mult is a Poisson RV (like # of photons) of length Vm = round(k*h) number of detectors? and B is array of powers (splited by BS?) of length 6.

Not sure why this statement is used to connect two things that are not related, even by the length.

I think this code is very buggy.

[Saint Dee]

Thanks @Bruno.Yes. For the initial 'Index exceeds matrix dimension' error, I have size(mult) = 1 x 460 and size(B) = 1 x 3, as instructed after changing some parameters and setting B = [0 0.5 1]. Actually, parameters h, hu, Vm, Vs and Vu are for placement of BSs and users within a simulation area as shown in the comment opposite each parameter. B is power reduction factor for the BS of length 3 in the new value. As I said, I'm just trying to find outputs I_1 through I_4, irrespective of individual parameter's dimensions. I will then take it up from there. Thanks

[Bruno Luong]

Please accept the answer if it helps you. Thanks

Answer 2

[madhan ravi]

Are you sure you have error there ? I faced a problem even before .

Total_Coord = [Xs Ys ones(size(Xs)) Xm Ym 2*ones(size(Xm))];

size(Xs) is 5750 and size(Xm) is 1150 how can you contain them in a matrix?

[Saint Dee]

@madhan, thanks. What could be done to correct this error? Seems they are building up more!