summaryrefslogtreecommitdiff
path: root/libm/ldouble/ldrand.c
diff options
context:
space:
mode:
authorEric Andersen <andersen@codepoet.org>2001-11-22 14:04:29 +0000
committerEric Andersen <andersen@codepoet.org>2001-11-22 14:04:29 +0000
commit7ce331c01ce6eb7b3f5c715a38a24359da9c6ee2 (patch)
tree3a7e8476e868ae15f4da1b7ce26b2db6f434468c /libm/ldouble/ldrand.c
parentc117dd5fb183afb1a4790a6f6110d88704be6bf8 (diff)
Totally rework the math library, this time based on the MacOs X
math library (which is itself based on the math lib from FreeBSD). -Erik
Diffstat (limited to 'libm/ldouble/ldrand.c')
-rw-r--r--libm/ldouble/ldrand.c175
1 files changed, 0 insertions, 175 deletions
diff --git a/libm/ldouble/ldrand.c b/libm/ldouble/ldrand.c
deleted file mode 100644
index 892b465df..000000000
--- a/libm/ldouble/ldrand.c
+++ /dev/null
@@ -1,175 +0,0 @@
-/* ldrand.c
- *
- * Pseudorandom number generator
- *
- *
- *
- * SYNOPSIS:
- *
- * double y;
- * int ldrand();
- *
- * ldrand( &y );
- *
- *
- *
- * DESCRIPTION:
- *
- * Yields a random number 1.0 <= y < 2.0.
- *
- * The three-generator congruential algorithm by Brian
- * Wichmann and David Hill (BYTE magazine, March, 1987,
- * pp 127-8) is used.
- *
- * Versions invoked by the different arithmetic compile
- * time options IBMPC, and MIEEE, produce the same sequences.
- *
- */
-
-
-
-#include <math.h>
-#ifdef ANSIPROT
-int ranwh ( void );
-#else
-int ranwh();
-#endif
-#ifdef UNK
-#undef UNK
-#if BIGENDIAN
-#define MIEEE
-#else
-#define IBMPC
-#endif
-#endif
-
-/* Three-generator random number algorithm
- * of Brian Wichmann and David Hill
- * BYTE magazine, March, 1987 pp 127-8
- *
- * The period, given by them, is (p-1)(q-1)(r-1)/4 = 6.95e12.
- */
-
-static int sx = 1;
-static int sy = 10000;
-static int sz = 3000;
-
-static union {
- long double d;
- unsigned short s[8];
-} unkans;
-
-/* This function implements the three
- * congruential generators.
- */
-
-int ranwh()
-{
-int r, s;
-
-/* sx = sx * 171 mod 30269 */
-r = sx/177;
-s = sx - 177 * r;
-sx = 171 * s - 2 * r;
-if( sx < 0 )
- sx += 30269;
-
-
-/* sy = sy * 172 mod 30307 */
-r = sy/176;
-s = sy - 176 * r;
-sy = 172 * s - 35 * r;
-if( sy < 0 )
- sy += 30307;
-
-/* sz = 170 * sz mod 30323 */
-r = sz/178;
-s = sz - 178 * r;
-sz = 170 * s - 63 * r;
-if( sz < 0 )
- sz += 30323;
-/* The results are in static sx, sy, sz. */
-return 0;
-}
-
-/* ldrand.c
- *
- * Random double precision floating point number between 1 and 2.
- *
- * C callable:
- * drand( &x );
- */
-
-int ldrand( a )
-long double *a;
-{
-unsigned short r;
-
-/* This algorithm of Wichmann and Hill computes a floating point
- * result:
- */
-ranwh();
-unkans.d = sx/30269.0L + sy/30307.0L + sz/30323.0L;
-r = unkans.d;
-unkans.d -= r;
-unkans.d += 1.0L;
-
-if( sizeof(long double) == 16 )
- {
-#ifdef MIEEE
- ranwh();
- r = sx * sy + sz;
- unkans.s[7] = r;
- ranwh();
- r = sx * sy + sz;
- unkans.s[6] = r;
- ranwh();
- r = sx * sy + sz;
- unkans.s[5] = r;
- ranwh();
- r = sx * sy + sz;
- unkans.s[4] = r;
- ranwh();
- r = sx * sy + sz;
- unkans.s[3] = r;
-#endif
-#ifdef IBMPC
- ranwh();
- r = sx * sy + sz;
- unkans.s[0] = r;
- ranwh();
- r = sx * sy + sz;
- unkans.s[1] = r;
- ranwh();
- r = sx * sy + sz;
- unkans.s[2] = r;
- ranwh();
- r = sx * sy + sz;
- unkans.s[3] = r;
- ranwh();
- r = sx * sy + sz;
- unkans.s[4] = r;
-#endif
- }
-else
- {
-#ifdef MIEEE
- ranwh();
- r = sx * sy + sz;
- unkans.s[5] = r;
- ranwh();
- r = sx * sy + sz;
- unkans.s[4] = r;
-#endif
-#ifdef IBMPC
- ranwh();
- r = sx * sy + sz;
- unkans.s[0] = r;
- ranwh();
- r = sx * sy + sz;
- unkans.s[1] = r;
-#endif
- }
-*a = unkans.d;
-return 0;
-}