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Diffstat (limited to 'report/pyp_clustering/acl09-short/code/cokus.c')
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diff --git a/report/pyp_clustering/acl09-short/code/cokus.c b/report/pyp_clustering/acl09-short/code/cokus.c deleted file mode 100644 index 3a959c0f..00000000 --- a/report/pyp_clustering/acl09-short/code/cokus.c +++ /dev/null @@ -1,167 +0,0 @@ -// This is the ``Mersenne Twister'' random number generator MT19937, which -// generates pseudorandom integers uniformly distributed in 0..(2^32 - 1) -// starting from any odd seed in 0..(2^32 - 1). This version is a recode -// by Shawn Cokus (Cokus@math.washington.edu) on March 8, 1998 of a version by -// Takuji Nishimura (who had suggestions from Topher Cooper and Marc Rieffel in -// July-August 1997). -// -// Effectiveness of the recoding (on Goedel2.math.washington.edu, a DEC Alpha -// running OSF/1) using GCC -O3 as a compiler: before recoding: 51.6 sec. to -// generate 300 million random numbers; after recoding: 24.0 sec. for the same -// (i.e., 46.5% of original time), so speed is now about 12.5 million random -// number generations per second on this machine. -// -// According to the URL <http://www.math.keio.ac.jp/~matumoto/emt.html> -// (and paraphrasing a bit in places), the Mersenne Twister is ``designed -// with consideration of the flaws of various existing generators,'' has -// a period of 2^19937 - 1, gives a sequence that is 623-dimensionally -// equidistributed, and ``has passed many stringent tests, including the -// die-hard test of G. Marsaglia and the load test of P. Hellekalek and -// S. Wegenkittl.'' It is efficient in memory usage (typically using 2506 -// to 5012 bytes of static data, depending on data type sizes, and the code -// is quite short as well). It generates random numbers in batches of 624 -// at a time, so the caching and pipelining of modern systems is exploited. -// It is also divide- and mod-free. -// -// This library is free software; you can redistribute it and/or modify it -// under the terms of the GNU Library General Public License as published by -// the Free Software Foundation (either version 2 of the License or, at your -// option, any later version). This library is distributed in the hope that -// it will be useful, but WITHOUT ANY WARRANTY, without even the implied -// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See -// the GNU Library General Public License for more details. You should have -// received a copy of the GNU Library General Public License along with this -// library; if not, write to the Free Software Foundation, Inc., 59 Temple -// Place, Suite 330, Boston, MA 02111-1307, USA. -// -// The code as Shawn received it included the following notice: -// -// Copyright (C) 1997 Makoto Matsumoto and Takuji Nishimura. When -// you use this, send an e-mail to <matumoto@math.keio.ac.jp> with -// an appropriate reference to your work. -// -// It would be nice to CC: <Cokus@math.washington.edu> when you write. -// - -#include <stdio.h> -#include <stdlib.h> - -// -// uint32 must be an unsigned integer type capable of holding at least 32 -// bits; exactly 32 should be fastest, but 64 is better on an Alpha with -// GCC at -O3 optimization so try your options and see what's best for you -// - -typedef unsigned long uint32; - -#define N (624) // length of state vector -#define M (397) // a period parameter -#define K (0x9908B0DFU) // a magic constant -#define hiBit(u) ((u) & 0x80000000U) // mask all but highest bit of u -#define loBit(u) ((u) & 0x00000001U) // mask all but lowest bit of u -#define loBits(u) ((u) & 0x7FFFFFFFU) // mask the highest bit of u -#define mixBits(u, v) (hiBit(u)|loBits(v)) // move hi bit of u to hi bit of v - -static uint32 state[N+1]; // state vector + 1 extra to not violate ANSI C -static uint32 *next; // next random value is computed from here -static int left = -1; // can *next++ this many times before reloading - - -void seedMT(uint32 seed) - { - // - // We initialize state[0..(N-1)] via the generator - // - // x_new = (69069 * x_old) mod 2^32 - // - // from Line 15 of Table 1, p. 106, Sec. 3.3.4 of Knuth's - // _The Art of Computer Programming_, Volume 2, 3rd ed. - // - // Notes (SJC): I do not know what the initial state requirements - // of the Mersenne Twister are, but it seems this seeding generator - // could be better. It achieves the maximum period for its modulus - // (2^30) iff x_initial is odd (p. 20-21, Sec. 3.2.1.2, Knuth); if - // x_initial can be even, you have sequences like 0, 0, 0, ...; - // 2^31, 2^31, 2^31, ...; 2^30, 2^30, 2^30, ...; 2^29, 2^29 + 2^31, - // 2^29, 2^29 + 2^31, ..., etc. so I force seed to be odd below. - // - // Even if x_initial is odd, if x_initial is 1 mod 4 then - // - // the lowest bit of x is always 1, - // the next-to-lowest bit of x is always 0, - // the 2nd-from-lowest bit of x alternates ... 0 1 0 1 0 1 0 1 ... , - // the 3rd-from-lowest bit of x 4-cycles ... 0 1 1 0 0 1 1 0 ... , - // the 4th-from-lowest bit of x has the 8-cycle ... 0 0 0 1 1 1 1 0 ... , - // ... - // - // and if x_initial is 3 mod 4 then - // - // the lowest bit of x is always 1, - // the next-to-lowest bit of x is always 1, - // the 2nd-from-lowest bit of x alternates ... 0 1 0 1 0 1 0 1 ... , - // the 3rd-from-lowest bit of x 4-cycles ... 0 0 1 1 0 0 1 1 ... , - // the 4th-from-lowest bit of x has the 8-cycle ... 0 0 1 1 1 1 0 0 ... , - // ... - // - // The generator's potency (min. s>=0 with (69069-1)^s = 0 mod 2^32) is - // 16, which seems to be alright by p. 25, Sec. 3.2.1.3 of Knuth. It - // also does well in the dimension 2..5 spectral tests, but it could be - // better in dimension 6 (Line 15, Table 1, p. 106, Sec. 3.3.4, Knuth). - // - // Note that the random number user does not see the values generated - // here directly since reloadMT() will always munge them first, so maybe - // none of all of this matters. In fact, the seed values made here could - // even be extra-special desirable if the Mersenne Twister theory says - // so-- that's why the only change I made is to restrict to odd seeds. - // - - register uint32 x = (seed | 1U) & 0xFFFFFFFFU, *s = state; - register int j; - - for(left=0, *s++=x, j=N; --j; - *s++ = (x*=69069U) & 0xFFFFFFFFU); - } - - -uint32 reloadMT(void) - { - register uint32 *p0=state, *p2=state+2, *pM=state+M, s0, s1; - register int j; - - if(left < -1) - seedMT(4357U); - - left=N-1, next=state+1; - - for(s0=state[0], s1=state[1], j=N-M+1; --j; s0=s1, s1=*p2++) - *p0++ = *pM++ ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U); - - for(pM=state, j=M; --j; s0=s1, s1=*p2++) - *p0++ = *pM++ ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U); - - s1=state[0], *p0 = *pM ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U); - s1 ^= (s1 >> 11); - s1 ^= (s1 << 7) & 0x9D2C5680U; - s1 ^= (s1 << 15) & 0xEFC60000U; - return(s1 ^ (s1 >> 18)); - } - - -inline uint32 randomMT(void) - { - uint32 y; - - if(--left < 0) - return(reloadMT()); - - y = *next++; - y ^= (y >> 11); - y ^= (y << 7) & 0x9D2C5680U; - y ^= (y << 15) & 0xEFC60000U; - y ^= (y >> 18); - return(y); - } - - - - |