Dann said:
To use the code from the book, try this (you will also need to link in
the object from cockus.c which contains the prng):
[lots of code, big snips]
I can't get COCKUS.C to compile, Dann:
$ gcc -D_GNU_SOURCE -Wall -Wextra -c COCKUS.C -o ****.o
gcc: error trying to exec 'cc1plus': execvp: Permission denied
$ ls -l | grep ****
-rw-r--r-- 1 dan dan 7789 2010-03-09 01:06 COCKUS.C
-rw-r--r-- 1 dan dan 7731 2000-02-24 15:23 COCKUS.C~
$ gcc -D_GNU_SOURCE -Wall -Wextra a1.c -o out
$ ./out
BAR.C
COCKUS.C
COCKUS.C~
CPPCOMP.H
DCOMP.H
DCSRLIC.TXT
DISTRIBS.C
DOUBLE.C
KEYXFRM.C
SICOMP.H
SINT.C
STRCOMP.H
STRINGS.C
TEST.C
status is 0
So this is all happening in the same directory, which is a good thing
when you're talking standard C. I get gcc to compile a1.c, which is a
linux utility written in C to show files that match \\.C in this case.
BTW, the poor guy's name is Cokus, so this is the worst of mistyping
when you're dealing with this name. The extra c turns the long O into a
short o, and you've made this fellow's name a fallic nightmare.
$ cat COCKUS.C
/*
** This is the home page of the Mersenne Twister PRNG:
**
http://www.math.keio.ac.jp/~matumoto/emt.html
**
** 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 (
[email protected]) 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 <
[email protected]> with
** an appropriate reference to your work.
**
** It would be nice to CC: <
[email protected]> when you write.
**
*/
#include <stdio.h>
#include <stdlib.h>
#include "mtrand.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;
/* length of state vector */
#define N (624)
/* a period parameter */
#define M (397)
/* a magic constant */
#define K (0x9908B0DFU)
/* mask all but highest bit of u */
#define hiBit(u) ((u) & 0x80000000U)
/* mask all but lowest bit of u */
#define loBit(u) ((u) & 0x00000001U)
/* mask the highest bit of u */
#define loBits(u) ((u) & 0x7FFFFFFFU)
/* move hi bit of u to hi bit of v */
#define mixBits(u, v) (hiBit(u)|loBits(v))
/* state vector + 1 extra to not violate ANSI C */
static uint32 state[N + 1];
/* next random value is computed from here */
static uint32 *next;
/* can *next++ this many times before reloading */
static int left = -1;
/*
**
** 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.
*/
void mtsrand(uint32 seed)
{
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)
mtsrand(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));
}
uint32 mtrand(void)
{
uint32 y;
if (--left < 0)
return (reloadMT());
y = *next++;
y ^= (y >> 11);
y ^= (y << 7) & 0x9D2C5680U;
y ^= (y << 15) & 0xEFC60000U;
return (y ^ (y >> 18));
}
#ifdef UNIT_TEST
int main(void)
{
int j;
/* you can seed with any uint32, but the best are odds in 0..(2^32
- 1) */
mtsrand(4357U);
/* print the first 2,002 random numbers seven to a line as an
example */
for (j = 0; j < 2002; j++)
printf(" %10lu%s", (unsigned long) mtrand(), (j % 7) == 6 ?
"\n" : "");
return (EXIT_SUCCESS);
}
#endif
// gcc -D_GNU_SOURCE -Wall -Wextra -c COCKUS.C -o ****.o
$
BTW, if Peter Seebach would look through this thread, he would see
evidence of me reading C reference on a night in which his crystal ball
erred on the side of sounding like my mormon ex-wife.
{