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SOME POPULAR PRN GENERATORS

  • Numbers uniformly distributed in [0,1]
  • Multiplicative Linear Congruential
  • (suggested by Lehmer 1951)
  • xi º mod [(a xi-1 + c), m]
  • x0= initial seed a,c,xi are integers in [0,m-1]
  • m = 2t ; t º # bits for integer representation
  • maximal period m
  • e. g.: m =24, a = 3, c = 1, x0= 2
  • 2, 7, 6, 3, 10, 15, 14, 11, 2, 7,¼ period =8
  • IBM generator RANDU in 60's and 70's: a = 65539, c = 0,
  • m =229 not recommended by today's standards