Attempted to access Pe(7); index must be a positive integer or logical.

I wrote this function but I get an error:

??? Attempted to access Pe(7); index must be a positive integer or logical.

Error in ==> prob3 at 56
        Pe(m)=(Pe(m)+error(j))/10000;
What should I do for it?

Pe=zeros(1,11);
x=zeros(1,10000);
y=zeros(1,10000);
z=zeros(1,10000);
error=zeros(1,10000);

for q=0:0.1:1
    for k=1:10000
        error(k)=0;
    end

      for i=1:10000
          if rand(1)<1/2
              x(i)=0;
              if rand(1)<q
                  y(i)=1;
                  if q<1/2
                      z(i)=1;
                  else
                      z(i)=0;
                  end
              else
                  y(i)=0;
                  if q>1/2
                      z(i)=1;
                  else
                      z(i)=0;
                  end
              end
          else 
              x(i)=1;
              if rand(1)<q
                  y(i)=1;
                  if q<1/2
                      z(i)=1;
                  else 
                      z(i)=0;
                  end
              else
                  y(i)=0;
                  if q>1/2
                      z(i)=1;
                  else 
                      z(i)=0;
                  end
              end
          end
          if x(i)==z(i)
              error(i)=error(i)+0;
          else
              error(i)=error(i)+1;
          end
      end
      m=(q./0.1)+1;
      for j=1:10000
          Pe(m)=(Pe(m)+error(j))/10000;
      end
  end
  plot(Pe,q);

Answer 1

[Richard Brown]

Your problem is that q and hence m are floating point numbers, not integers. in this case the problem is that

m = 0.6 / 0.1 + 1

differs from 7 in the sixteenth decimal place, and hence can't be used to index. Either use

m = round(q / 0.1 + 1)

or, better, use integer indices in your loop, and compute q from them