how can i solve this 'Undefined function or variable '?'.

i get this error 'Undefined function or variable' however i defined it. how do i solve it? i think i should insect bounds, that will tell my code to stop is all nodes are in a cluster and continue when (remainder) there are still nodes remain that are not in a cluster, but i am failing to come up with a working code. please help me

here is my code

    N=50 % number of nodes
    Dreq=2, dij=distance matrix with rand no. from 1-10

%%%%%%%%%Cluster_9 %%%%%%%%%%

       kk = 0;
        k = 0;
       for v = 1:length(remainder_7)
          if dij(node_k,remainder_7(v))<= Dreq
              k = k+1;
              cluster_9(k)= remainder_7(v);
          else kk = kk+1;
              remainder_8(kk)= remainder_7(v);  % remaining nodes that are not visited
          end
      end

    for k =1:length(cluster_9)
         for k1=1:length(cluster_9)
        dij9(k,k1)=dij(cluster_9(k),cluster_9(k1)); % distances in cluster_9
         end
        end

        candidate_n8(1)=node_k;
        Lavg9(1)= Lavg(node_k);

        k=0;
        for n = 1:length(cluster_9)

        if cluster_9(n)~=node_k

        if max(dij9(n,:))<=Dreq && Lavg(cluster_9(n))<Lavg(node_k)
        k=k+1;
        candidate_n8(k)=cluster_9(n);
        Lavg8(k)=Lavg(cluster_9(n));
        end

        end

        end
        [~,index]=min(Lavg9);
        node_n = candidate_n8(index);

        Controller(9)=node_n;

        % finding the node in the remainder that is near the cluster_9
        k = 0;
        for k1 =1:length(cluster_9)
          for k2 =1:length(remainder_8)
              k = k+1;
              DIJ_8(k) = dij(cluster_9(k1),remainder_8(k2));
              TABLE(k,1) = k2;
          end
        end

        [~,index] = min(DIJ_8);
        node_k = remainder_8(TABLE(index,1));

        %%%%%%%%%%Clister_10%%%%%%%%%%
        kk = 0;
        k = 0;
        for v = 1:length(remainder_8)
            if dij(node_k,remainder_8(v))<= Dreq
                k = k+1;
                cluster_10(k)= remainder_8(v);
            else kk = kk+1;
                remainder_9(kk)= remainder_8(v);  % remaining nodes that are not visited
            end
        end

        for k =1:length(cluster_10)
         for k1=1:length(cluster_10)
        dij10(k,k1)=dij(cluster_10(k),cluster_10(k1));  % distances in cluster_10
         end
        end

        candidate_n9(1)=node_k;
        Lavg10(1)= Lavg(node_k);

        k=0;
        for n = 1:length(cluster_10)

        if cluster_10(n)~=node_k

        if max(dij10(n,:))<=Dreq && Lavg(cluster_10(n))<Lavg(node_k)
        k=k+1;
        candidate_n9(k)=cluster_10(n);
        Lavg9(k)=Lavg(cluster_10(n));
        end

        end

        end
        [~,index]=min(Lavg10);
        node_n = candidate_n9(index);

        Controller(10)=node_n;
        end

      Undefined function or variable 'remainder_8'.

      Error in my_code (line 518)
        for k2 =1:length(remainder_8)

[Stephen23]

@mathapelo mokgoatsane: please show us the complete error message. This means all of the red text.

[Torsten]

I can't see a variable named "remainder_8" in your code.

[mathapelo mokgoatsane]

the error line changes when you run the code

[Adam]

Please format your code! You can't seriously expect anyone to plough through all that?! Even formatted it is a lot of code to look through, but unformatted it is unreadable!

https://uk.mathworks.com/matlabcentral/answers/13205-tutorial-how-to-format-your-question-with-markup#answer_18099

[mathapelo mokgoatsane]

thank you @Adam

[Adam]

remainder_8 is only created in an else statement. Presumably in the case you are running your code never goes into the else and so the variable does not exist. If this is a valid scenario you should create an empty variable somewhere towards the top of your code e.g.

remainder_8 = [];

then

length( remainder_8 )

will return 0, though then the error will just move to this line:

node_k = remainder_8(TABLE(index,1));

where you again assume this variable exists.

Answer 1

[Walter Roberson]

   for v = 1:length(remainder_7)
     if dij(node_k,remainder_7(v))<= Dreq
       k = k+1;
       cluster_9(k)= remainder_7(v); 
     else
       kk = kk+1;
       remainder_8(kk)= remainder_7(v); % remaining nodes that are not visited
     end 
   end

In that code if the else is never true then remainder_8 will never be defined.

Answer 2

[Stephen23]

The problem is simple: remainder_8 does not exist, because your code never defines it. Think about what happens when all of the sampled dij values are <= Dreq:

    for ...
        if dij(node_k,remainder_7(v))<= Dreq
            ...
        else ...
            remainder_8(kk) = ...
        end
    end

then remainder_8 will simply never be defined. Solution: put this at the start of your code:

remainder_ = [];

[mathapelo mokgoatsane]

 thank you, now i am starting to see where i went wrong.