How can I avoid infinite while loop?
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N = 1; while (N<11) n = ((N*2)+(N+1))/N; N = n end
I wish to assign the value of 'n' to 'N' and compare if it's less than '11' and again enter the loop until 'N' is equal to 11. Please help.
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Accepted Answer
  dpb
      
      
 on 11 Jul 2014
        Well, since
 ((N*2)+(N+1))/N = (2*N+N+1)/N = (3*N+1)/N
n=3+1/N
and the expression approaches 3+ as a limit, never approaching anything near 11, the answer to the question posed is "you can't".
Need a different problem statement; perhaps you're looking for the point at which the change is less than some epsilon or something of that nature?
I'll wait for clarification of the actual problem nature before guessing further...
More Answers (2)
  Daniel
      
 on 11 Jul 2014
        Set a number equal to the number of times you want to loop (this case I chose 11), subtract each time you're in the loop, and add an and condition
LOOP_LIMIT = 11;
N = 1;
while (N < 11 && LOOP_LIMIT > 0)
    n = ((N*2)+(N+1))/N;
    N = n;
    LOOP_LIMIT = LOOP_LIMIT-1;
end
  C.J. Harris
      
 on 11 Jul 2014
        
      Edited: C.J. Harris
      
 on 11 Jul 2014
  
      You have an infinity loop because your seed (N) is starting at one. Note that your equation ((N*2)+(N+1))/N is in fact equal to 3+(1/N), thereby meaning you'll only get 11 (or greater) for values less than 0.125.
Not sure why you even need a loop, can't you just rearrange, therefore getting n = 1/(11-3) = 0.125.
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