1This is a Mersenne Twister pseudorandom number generator 2with period 2^19937-1 with improved initialization scheme, 3modified on 2002/1/26 by Takuji Nishimura and Makoto Matsumoto. 4 5Contents of this tar ball: 6readme-mt.txt this file 7mt19937ar.c the C source (ar: initialize by ARray) 8mt19937ar.out Test outputs of six types generators. 1000 for each 9 101. Initialization 11 The initialization scheme for the previous versions of MT 12(e.g. 1999/10/28 version or earlier) has a tiny problem, that 13the most significant bits of the seed is not well reflected 14to the state vector of MT. 15 16This version (2002/1/26) has two initialization schemes: 17init_genrand(seed) and init_by_array(init_key, key_length). 18 19init_genrand(seed) initializes the state vector by using 20one unsigned 32-bit integer "seed", which may be zero. 21 22init_by_array(init_key, key_length) initializes the state vector 23by using an array init_key[] of unsigned 32-bit integers 24of length key_kength. If key_length is smaller than 624, 25then each array of 32-bit integers gives distinct initial 26state vector. This is useful if you want a larger seed space 27than 32-bit word. 28 292. Generation 30After initialization, the following type of pseudorandom numbers 31are available. 32 33genrand_int32() generates unsigned 32-bit integers. 34genrand_int31() generates unsigned 31-bit integers. 35genrand_real1() generates uniform real in [0,1] (32-bit resolution). 36genrand_real2() generates uniform real in [0,1) (32-bit resolution). 37genrand_real3() generates uniform real in (0,1) (32-bit resolution). 38genrand_res53() generates uniform real in [0,1) with 53-bit resolution. 39 40Note: the last five functions call the first one. 41if you need more speed for these five functions, you may 42suppress the function call by copying genrand_int32() and 43replacing the last return(), following to these five functions. 44 453. main() 46main() is an example to initialize with an array of length 4, 47then 1000 outputs of unsigned 32-bit integers, 48then 1000 outputs of real [0,1) numbers. 49 504. The outputs 51The output of the mt19937ar.c is in the file mt19937ar.out. 52If you revise or translate the code, check the output 53by using this file. 54 555. Cryptography 56This generator is not cryptoraphically secure. 57You need to use a one-way (or hash) function to obtain 58a secure random sequence. 59 606. Correspondence 61See: 62URL http://www.math.keio.ac.jp/matumoto/emt.html 63email matumoto@math.keio.ac.jp, nisimura@sci.kj.yamagata-u.ac.jp 64 657. Reference 66M. Matsumoto and T. Nishimura, 67"Mersenne Twister: A 623-Dimensionally Equidistributed Uniform 68Pseudo-Random Number Generator", 69ACM Transactions on Modeling and Computer Simulation, 70Vol. 8, No. 1, January 1998, pp 3--30. 71 72------- 73Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura, 74All rights reserved. 75