could anyone help me how to overcome the following error

 G=rand(50,100)
C=rand(50,100)

 N_G=15;%No of group
              R = cell(N_G,1)
              sumR = cell(N_G,1)

             for d=1:1:N_G
    %------------------------------------------
    %   select No of UE randomly
    %------------------------------------------
                  if d==N_G
                      sz=length(C(:,1))
                      e=sz
                  else
                      if d==1
                          e=randi([1 9])% select No of UE randomly
                      else
                          sz=length(C(:,1))
                          sz=ceil(sz/2)
                          e=randi([1 sz])% select No of UE randomly

                      end
                  end
    %------------------------------------------
                  idx=randsample(1:size(C,1),e);
    %------------------------------------------
    %   Getting arry G and C from random index 
    %------------------------------------------  
                  for s=1:length(idx)
                  X(s,:) = C(idx(s),:)
                  Y(s,:) = G(idx(s),:)
                  Xi(s)=find(X(s,:))    
                  end
                  X=[X(1:s,:)]
                  Y=[Y(1:s,:)]                
    %------------------------------------------
    %   Replacing  
    %------------------------------------------           
                 non_0=sum(X)
                 non_0=repmat(non_0,s,1)
                 S=X
                 S(non_0 & X==0)=Y(non_0 & X==0);
                 Z{d}=S
    %-----------------------------------------------------
    %   deleting the first output from the main array  
    %-----------------------------------------------------
                  G(idx,:) = []
                  C(idx,:) = [] 

             end

           W=[Z{1};Z{2};Z{3};Z{4};Z{5};Z{6};Z{7};Z{8};Z{9};Z{10};Z{11};Z{12};Z{13};Z{14};Z{15}]

If i run the following code i am getting Error (line 36) Xi(s)=find(X(s,:)) In an assignment A(I) = B, the number of elements in B and I must be the same.

Could anyone help me to solve the following issue.

Answer 1

[Walter Roberson]

You have

                  for s=1:length(idx)
                  X(s,:) = C(idx(s),:)
                  Y(s,:) = G(idx(s),:)
                  Xi(s)=find(X(s,:))    
                  end

C has been assigned a 50 x 100 array. s is a scalar. idx(s) is a scalar. So C(idx(s),:) is going to be exactly one row out of C, so X(s,:) is going to be 1 x 100.

Now at the start, C is all non-zero because rand() never generates 0. So X(s,:) is going to start out all non-zero, so find(X(s,:)) is going to return all 100 indices because they are all non-zero locations. You try to assign those 100 indices to Xi(s) but Xi(s) only has room for a scalar.

You never use Xi again, so there is no obvious reason why you are computing Xi.