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Random Check (Posted on 2005-02-11) Difficulty: 3 of 5
In doing computer simulations, such as the one I wrote for simulating the results of part 2 of Rumor Mill, one often uses a random number generator that's built into the computer language. These generators are based on a seed (some arbitrary number) and are mixed up at each step that calls for a random number. There are only a finite number of seeds, and each one is based mechanically on the previous, so they necessarily repeat after a while.

The seed is kept internally, away from the programmer's view, so the programmer can't ask for, say, the next random number after .753372.

If one suspects that the repetition cycle is actually occuring within the length of the run that he needs, what algorithm can you put into the program to find the period with which your results are repeating (and are therefore no longer random, or rather no longer independent trials)? Assume you do not have room to store all the numbers as they arrive, nor can you afford the time it would take to compare each new number to all the preceding numbers.

Then also, how do you determine where the repetition cycle begins (after what iteration of the loop of trials).

See The Solution Submitted by Charlie    
Rating: 3.0000 (3 votes)

Comments: ( You must be logged in to post comments.)
  Subject Author Date
There is no solution, only statistically relevant testsFrankM2008-01-19 21:21:25
SolutionNo SubjectKen Haley2005-02-20 05:33:58
VB Program (coded algorithm)Penny2005-02-14 03:16:19
SolutionNo SubjectKen Haley2005-02-12 18:14:27
re: Probable SolutionCharlie2005-02-12 17:56:03
Some ThoughtsPossible solutionTristan2005-02-12 17:48:58
another tryLarry2005-02-12 16:12:12
Probable SolutionEric2005-02-12 15:53:50
re: Am I oversimplifying?Charlie2005-02-11 18:08:54
Maybe this would workLarry2005-02-11 17:30:43
QuestionAm I oversimplifying?SteveH2005-02-11 17:25:14
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