ranrotb.cpp

random number generator,随机数产生器

/************************* RANROTB.CPP ****************** AgF 1999-03-03 *
*  Random Number generator 'RANROT' type B                               *
*                                                                        *
*  This is a lagged-Fibonacci type of random number generator with       *
*  rotation of bits.  The algorithm is:                                  *
*  X[n] = ((X[n-j] rotl r1) + (X[n-k] rotl r2)) modulo 2^b               *
*                                                                        *
*  The last k values of X are stored in a circular buffer named          *
*  randbuffer.                                                           *
*  The code includes a self-test facility which will detect any          *
*  repetition of previous states.                                        *
*                                                                        *
*  The theory of the RANROT type of generators and the reason for the    *
*  self-test are described at www.agner.org/random                       *
*                                                                        *
*