Commit c838b2a0 authored by Sebastian Wilhelmi's avatar Sebastian Wilhelmi Committed by Sebastian Wilhelmi

Improved the seeding algorithm. Old behaviour can be achived by setting


2002-11-26  Sebastian Wilhelmi  <wilhelmi@ira.uka.de>

	* glib/grand.c, gthread/gthread-impl.c, tests/rand-test.c:
	Improved the seeding algorithm. Old behaviour can be achived by
	setting envvar G_RANDOM_VERSION to "2.0". (#99262)

	* docs/reference/glib/glib-docs.sgml,
	docs/reference/glib/Makefile.am: Renamed
	docs/reference/glib/changes-2.0.sgml to
	docs/reference/glib/changes.sgml and added section for changes
	from 2.0 to 2.2 (Also corrected 1.0 to 1.2).

	* README.in, docs/reference/glib/running.sgml,
	docs/reference/glib/tmpl/random_numbers.sgml,
	docs/reference/glib/changes.sgml: Added notes about the new
	seeding algorithm.
parent 17344bb1
2002-11-26 Sebastian Wilhelmi <wilhelmi@ira.uka.de>
* glib/grand.c, gthread/gthread-impl.c, tests/rand-test.c:
Changed the seeding algorithm. Old behaviour can be achived by
setting envvar G_RANDOM_VERSION to "2.0". (#99262)
* docs/reference/glib/glib-docs.sgml,
docs/reference/glib/Makefile.am: Renamed
docs/reference/glib/changes-2.0.sgml to
docs/reference/glib/changes.sgml and added section for changes
from 2.0 to 2.2 (Also corrected 1.0 to 1.2).
* README.in, docs/reference/glib/running.sgml,
docs/reference/glib/tmpl/random_numbers.sgml,
docs/reference/glib/changes.sgml: Added notes about the new
seeding algorithm.
* configure.in: Make CPPFLAGS, not CFLAGS, include
G_THREAD_CFLAGS. CFLAGS is used while linking too and thus GLib
programs would link to the threads library on some platforms. Also
fixed a bug manifesting through this change.
fixed a bug manifesting through this change. (#77981)
2002-11-26 Matthias Clasen <maclas@gmx.de>
......
2002-11-26 Sebastian Wilhelmi <wilhelmi@ira.uka.de>
* glib/grand.c, gthread/gthread-impl.c, tests/rand-test.c:
Changed the seeding algorithm. Old behaviour can be achived by
setting envvar G_RANDOM_VERSION to "2.0". (#99262)
* docs/reference/glib/glib-docs.sgml,
docs/reference/glib/Makefile.am: Renamed
docs/reference/glib/changes-2.0.sgml to
docs/reference/glib/changes.sgml and added section for changes
from 2.0 to 2.2 (Also corrected 1.0 to 1.2).
* README.in, docs/reference/glib/running.sgml,
docs/reference/glib/tmpl/random_numbers.sgml,
docs/reference/glib/changes.sgml: Added notes about the new
seeding algorithm.
* configure.in: Make CPPFLAGS, not CFLAGS, include
G_THREAD_CFLAGS. CFLAGS is used while linking too and thus GLib
programs would link to the threads library on some platforms. Also
fixed a bug manifesting through this change.
fixed a bug manifesting through this change. (#77981)
2002-11-26 Matthias Clasen <maclas@gmx.de>
......
2002-11-26 Sebastian Wilhelmi <wilhelmi@ira.uka.de>
* glib/grand.c, gthread/gthread-impl.c, tests/rand-test.c:
Changed the seeding algorithm. Old behaviour can be achived by
setting envvar G_RANDOM_VERSION to "2.0". (#99262)
* docs/reference/glib/glib-docs.sgml,
docs/reference/glib/Makefile.am: Renamed
docs/reference/glib/changes-2.0.sgml to
docs/reference/glib/changes.sgml and added section for changes
from 2.0 to 2.2 (Also corrected 1.0 to 1.2).
* README.in, docs/reference/glib/running.sgml,
docs/reference/glib/tmpl/random_numbers.sgml,
docs/reference/glib/changes.sgml: Added notes about the new
seeding algorithm.
* configure.in: Make CPPFLAGS, not CFLAGS, include
G_THREAD_CFLAGS. CFLAGS is used while linking too and thus GLib
programs would link to the threads library on some platforms. Also
fixed a bug manifesting through this change.
fixed a bug manifesting through this change. (#77981)
2002-11-26 Matthias Clasen <maclas@gmx.de>
......
2002-11-26 Sebastian Wilhelmi <wilhelmi@ira.uka.de>
* glib/grand.c, gthread/gthread-impl.c, tests/rand-test.c:
Changed the seeding algorithm. Old behaviour can be achived by
setting envvar G_RANDOM_VERSION to "2.0". (#99262)
* docs/reference/glib/glib-docs.sgml,
docs/reference/glib/Makefile.am: Renamed
docs/reference/glib/changes-2.0.sgml to
docs/reference/glib/changes.sgml and added section for changes
from 2.0 to 2.2 (Also corrected 1.0 to 1.2).
* README.in, docs/reference/glib/running.sgml,
docs/reference/glib/tmpl/random_numbers.sgml,
docs/reference/glib/changes.sgml: Added notes about the new
seeding algorithm.
* configure.in: Make CPPFLAGS, not CFLAGS, include
G_THREAD_CFLAGS. CFLAGS is used while linking too and thus GLib
programs would link to the threads library on some platforms. Also
fixed a bug manifesting through this change.
fixed a bug manifesting through this change. (#77981)
2002-11-26 Matthias Clasen <maclas@gmx.de>
......
2002-11-26 Sebastian Wilhelmi <wilhelmi@ira.uka.de>
* glib/grand.c, gthread/gthread-impl.c, tests/rand-test.c:
Changed the seeding algorithm. Old behaviour can be achived by
setting envvar G_RANDOM_VERSION to "2.0". (#99262)
* docs/reference/glib/glib-docs.sgml,
docs/reference/glib/Makefile.am: Renamed
docs/reference/glib/changes-2.0.sgml to
docs/reference/glib/changes.sgml and added section for changes
from 2.0 to 2.2 (Also corrected 1.0 to 1.2).
* README.in, docs/reference/glib/running.sgml,
docs/reference/glib/tmpl/random_numbers.sgml,
docs/reference/glib/changes.sgml: Added notes about the new
seeding algorithm.
* configure.in: Make CPPFLAGS, not CFLAGS, include
G_THREAD_CFLAGS. CFLAGS is used while linking too and thus GLib
programs would link to the threads library on some platforms. Also
fixed a bug manifesting through this change.
fixed a bug manifesting through this change. (#77981)
2002-11-26 Matthias Clasen <maclas@gmx.de>
......
2002-11-26 Sebastian Wilhelmi <wilhelmi@ira.uka.de>
* glib/grand.c, gthread/gthread-impl.c, tests/rand-test.c:
Changed the seeding algorithm. Old behaviour can be achived by
setting envvar G_RANDOM_VERSION to "2.0". (#99262)
* docs/reference/glib/glib-docs.sgml,
docs/reference/glib/Makefile.am: Renamed
docs/reference/glib/changes-2.0.sgml to
docs/reference/glib/changes.sgml and added section for changes
from 2.0 to 2.2 (Also corrected 1.0 to 1.2).
* README.in, docs/reference/glib/running.sgml,
docs/reference/glib/tmpl/random_numbers.sgml,
docs/reference/glib/changes.sgml: Added notes about the new
seeding algorithm.
* configure.in: Make CPPFLAGS, not CFLAGS, include
G_THREAD_CFLAGS. CFLAGS is used while linking too and thus GLib
programs would link to the threads library on some platforms. Also
fixed a bug manifesting through this change.
fixed a bug manifesting through this change. (#77981)
2002-11-26 Matthias Clasen <maclas@gmx.de>
......
2002-11-26 Sebastian Wilhelmi <wilhelmi@ira.uka.de>
* glib/grand.c, gthread/gthread-impl.c, tests/rand-test.c:
Changed the seeding algorithm. Old behaviour can be achived by
setting envvar G_RANDOM_VERSION to "2.0". (#99262)
* docs/reference/glib/glib-docs.sgml,
docs/reference/glib/Makefile.am: Renamed
docs/reference/glib/changes-2.0.sgml to
docs/reference/glib/changes.sgml and added section for changes
from 2.0 to 2.2 (Also corrected 1.0 to 1.2).
* README.in, docs/reference/glib/running.sgml,
docs/reference/glib/tmpl/random_numbers.sgml,
docs/reference/glib/changes.sgml: Added notes about the new
seeding algorithm.
* configure.in: Make CPPFLAGS, not CFLAGS, include
G_THREAD_CFLAGS. CFLAGS is used while linking too and thus GLib
programs would link to the threads library on some platforms. Also
fixed a bug manifesting through this change.
fixed a bug manifesting through this change. (#77981)
2002-11-26 Matthias Clasen <maclas@gmx.de>
......
......@@ -24,6 +24,22 @@ Installation
See the file 'INSTALL'
Notes about GLib-2.2.0
======================
* GLib changed the seeding algorithm for the pseudo-random number
generator Mersenne Twister, as used by GRand and GRandom. This was
necessary, because some seeds would yield very bad pseudo-random
streams. Further information can be found at:
http://www.math.keio.ac.jp/~matumoto/emt.html
The original seeding algorithm, as found in GLib-2.0.x, can be used
instead of the new one by setting the environment variable
G_RANDOM_VERSION to the value of "2.0". Use the GLib-2.0 algorithm
only if you have sequences of numbers generated with Glib-2.0 that
you need to reproduce exactly.
How to report bugs
==================
......
......@@ -48,7 +48,7 @@ HTML_IMAGES = \
content_files = \
running.sgml \
building.sgml \
changes-2.0.sgml \
changes.sgml \
compiling.sgml \
resources.sgml \
version.xml
......
<refentry id="glib-changes-2-0" revision="17 Jan 2002">
<refentry id="glib-changes" revision="17 Jan 2002">
<refmeta>
<refentrytitle>Changes from 1.0 to 2.0</refentrytitle>
<refentrytitle>Changes to GLib</refentrytitle>
<manvolnum>3</manvolnum>
<refmiscinfo>Changes from 1.0 to 2.0</refmiscinfo>
<refmiscinfo>Changes to GLib</refmiscinfo>
</refmeta>
<refnamediv>
<refname>Changes from 1.0 to 2.0</refname>
<refname>Changes to GLib</refname>
<refpurpose>
Incompatible changes made between version 1.0 and version 2.0
Incompatible changes made between successing versions of GLib
</refpurpose>
</refnamediv>
<refsect1>
<title>Incompatible changes from 1.0 to 2.0</title>
<title>Incompatible changes from 2.0 to 2.2</title>
<itemizedlist>
<listitem>
<para>
GLib changed the seeding algorithm for the pseudo-random number
generator Mersenne Twister, as used by <structname>GRand</structname>
and <structname>GRandom</structname>. This was necessary, because some
seeds would yield very bad pseudo-random streams.
</para>
<para>
Further information can be found at the website of the Mersenne
Twister random number generator at <ulink
url="http://www.math.keio.ac.jp/~matumoto/emt.html">http://www.math.keio.ac.jp/~matumoto/emt.html</ulink>.
</para>
<para>
The original seeding algorithm, as found in GLib 2.0.x, can be used
instead of the new one by setting the environment variable
<envar>G_RANDOM_VERSION</envar> to the value of '2.0'. Use the
GLib-2.0 algorithm only if you have sequences of numbers generated
with Glib-2.0 that you need to reproduce exactly.
</para>
</listitem>
</itemizedlist>
</refsect1>
<refsect1>
<title>Incompatible changes from 1.2 to 2.0</title>
<para>
The <ulink url="http://developer.gnome.org/dotplan/porting/">GNOME 2.0
porting guide</ulink> on <ulink
url="http://developer.gnome.org">http://developer.gnome.org</ulink>
has some more detailed discussion of porting from 1.0 to 2.0.
has some more detailed discussion of porting from 1.2 to 2.0.
See the section on GLib.
</para>
......
......@@ -58,7 +58,7 @@
<!ENTITY glib-Building SYSTEM "building.sgml">
<!ENTITY glib-Running SYSTEM "running.sgml">
<!ENTITY glib-Resources SYSTEM "resources.sgml">
<!ENTITY glib-Changes-2-0 SYSTEM "changes-2.0.sgml">
<!ENTITY glib-Changes SYSTEM "changes.sgml">
<!ENTITY version SYSTEM "version.xml">
]>
......@@ -107,7 +107,7 @@ implementations, e.g. POSIX threads, DCE threads or Solaris threads.
&glib-Building;
&glib-Compiling;
&glib-Running;
&glib-Changes-2-0;
&glib-Changes;
&glib-Resources;
</chapter>
......
......@@ -62,6 +62,17 @@ variables like <envar>LANG</envar>, <envar>PATH</envar> or <envar>HOME</envar>.
</para>
</formalpara>
<formalpara>
<title><envar>G_RANDOM_VERSION</envar></title>
<para>
If this environment variable is set to '2.0', the outdated
pseudo-random number seeding algorithm from GLib-2.0 is used
instead of the new better one. Use the GLib-2.0 algorithm only if
you have sequences of numbers generated with Glib-2.0 that you
need to reproduce exactly.
</para>
</formalpara>
</refsect2>
<refsect2>
......
......@@ -2,12 +2,12 @@
Random Numbers
<!-- ##### SECTION Short_Description ##### -->
pseudo random number generator.
pseudo-random number generator.
<!-- ##### SECTION Long_Description ##### -->
<para>
The following functions allow you to use a portable, fast and good
pseudo random number generator (PRNG). It uses the Mersenne Twister
pseudo-random number generator (PRNG). It uses the Mersenne Twister
PRNG, which was originally developed by Makoto Matsumoto and Takuji
Nishimura. Further information can be found at <ulink
url="http://www.math.keio.ac.jp/~matumoto/emt.html"
......@@ -32,6 +32,18 @@ equally distributed random numbers, whereas for example the
yield equally distributed numbers.
</para>
<para>
GLib changed the seeding algorithm for the pseudo-random number
generator Mersenne Twister, as used by <structname>GRand</structname>
and <structname>GRandom</structname>. This was necessary, because some
seeds would yield very bad pseudo-random streams. The original seeding
algorithm, as found in GLib 2.0.x, can be used instead of the new one
by setting the environment variable <envar>G_RANDOM_VERSION</envar> to
the value of '2.0'. Use the GLib-2.0 algorithm only if you have
sequences of numbers generated with Glib-2.0 that you need to
reproduce exactly.
</para>
<!-- ##### SECTION See_Also ##### -->
<para>
......
......@@ -58,6 +58,41 @@ static GRand* global_random = NULL;
#define TEMPERING_SHIFT_T(y) (y << 15)
#define TEMPERING_SHIFT_L(y) (y >> 18)
static guint
get_random_version (void)
{
static gboolean initialized = FALSE;
static guint random_version;
if (!initialized)
{
const gchar *version_string = g_getenv ("G_RANDOM_VERSION");
if (!version_string || version_string[0] == '\000' ||
strcmp (version_string, "2.2") == 0)
random_version = 22;
else if (strcmp (version_string, "2.0") == 0)
random_version = 20;
else
{
g_warning ("Unknown G_RANDOM_VERSION \"%s\". Using version 2.2.",
version_string);
random_version = 22;
}
initialized = TRUE;
}
return random_version;
}
/* This is called from g_thread_init(). It's used to
* initialize some static data in a threadsafe way.
*/
void
g_rand_init (void)
{
(void)get_random_version ();
}
struct _GRand
{
guint32 mt[N]; /* the array for the state vector */
......@@ -148,17 +183,35 @@ g_rand_set_seed (GRand* rand, guint32 seed)
{
g_return_if_fail (rand != NULL);
/* setting initial seeds to mt[N] using */
/* the generator Line 25 of Table 1 in */
/* [KNUTH 1981, The Art of Computer Programming */
/* Vol. 2 (2nd Ed.), pp102] */
if (seed == 0) /* This would make the PRNG procude only zeros */
seed = 0x6b842128; /* Just set it to another number */
rand->mt[0]= seed & 0xffffffff;
for (rand->mti=1; rand->mti<N; rand->mti++)
rand->mt[rand->mti] = (69069 * rand->mt[rand->mti-1]) & 0xffffffff;
switch (get_random_version ())
{
case 20:
/* setting initial seeds to mt[N] using */
/* the generator Line 25 of Table 1 in */
/* [KNUTH 1981, The Art of Computer Programming */
/* Vol. 2 (2nd Ed.), pp102] */
if (seed == 0) /* This would make the PRNG procude only zeros */
seed = 0x6b842128; /* Just set it to another number */
rand->mt[0]= seed;
for (rand->mti=1; rand->mti<N; rand->mti++)
rand->mt[rand->mti] = (69069 * rand->mt[rand->mti-1]);
break;
case 22:
/* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
/* In the previous version (see above), MSBs of the */
/* seed affect only MSBs of the array mt[]. */
rand->mt[0]= seed;
for (rand->mti=1; rand->mti<N; rand->mti++)
rand->mt[rand->mti] = 1812433253UL *
(rand->mt[rand->mti-1] ^ (rand->mt[rand->mti-1] >> 30)) + rand->mti;
break;
default:
g_assert_not_reached ();
}
}
/**
......
......@@ -66,6 +66,7 @@ void g_mutex_init (void);
void g_mem_init (void);
void g_messages_init (void);
void g_convert_init (void);
void g_rand_init (void);
void g_main_thread_init (void);
#define G_MUTEX_DEBUG_INFO(mutex) (*((gpointer*)(((char*)mutex)+G_MUTEX_SIZE)))
......@@ -382,6 +383,7 @@ g_thread_init (GThreadFunctions* init)
g_mem_init ();
g_messages_init ();
g_convert_init ();
g_rand_init ();
g_main_thread_init ();
/* now we can set g_threads_got_initialized and thus enable
......
......@@ -6,26 +6,26 @@
const gint32 first_numbers[] =
{
0x7a7a7a7a,
0x20aea82a,
0xcab337ab,
0xdcf770ea,
0xdf552b2f,
0x32d1ef7f,
0x6bed6dd9,
0x7222df44,
0x6b842128,
0x07f8579a,
0x9dad1004,
0x2df264f2,
0x13b48989,
0xf2929475,
0x30f30c97,
0x3f9a1ea7,
0x3bf04710,
0xb85bd69e,
0x790a48b0,
0xfa06b85f,
0xa64cc9e3
0xfdcc2d54,
0x3a279ceb,
0xc4d39c33,
0xf31895cd,
0x46ca0afc,
0x3f5484ff,
0x54bc9557,
0xed2c24b1,
0x84062503,
0x8f6404b3,
0x599a94b3,
0xe46d03d5,
0x310beb78,
0x7bee5d08,
0x760d09be,
0x59b6e163,
0xbf6d16ec,
0xcca5fb54,
0x5de7259b,
0x1696330c,
};
const gint length = sizeof (first_numbers) / sizeof (first_numbers[0]);
......
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