--- _SB/Libc/gen/FreeBSD/rand48.3 2004-11-25 11:38:01.000000000 -0800 +++ _SB/Libc/gen/FreeBSD/rand48.3.edit 2006-06-28 16:55:51.000000000 -0700 @@ -18,51 +18,68 @@ .Sh NAME .Nm drand48 , .Nm erand48 , +.Nm jrand48 , +.Nm lcong48 , .Nm lrand48 , -.Nm nrand48 , .Nm mrand48 , -.Nm jrand48 , -.Nm srand48 , +.Nm nrand48 , .Nm seed48 , -.Nm lcong48 +.Nm srand48 .Nd pseudo random number generators and initialization routines .Sh LIBRARY .Lb libc .Sh SYNOPSIS .In stdlib.h .Ft double -.Fn drand48 void +.Fo drand48 +.Fa void +.Fc .Ft double -.Fn erand48 "unsigned short xseed[3]" +.Fo erand48 +.Fa "unsigned short xsubi[3]" +.Fc .Ft long -.Fn lrand48 void +.Fo jrand48 +.Fa "unsigned short xsubi[3]" +.Fc +.Ft void +.Fo lcong48 +.Fa "unsigned short param[7]" +.Fc .Ft long -.Fn nrand48 "unsigned short xseed[3]" +.Fo lrand48 +.Fa void +.Fc .Ft long -.Fn mrand48 void +.Fo mrand48 +.Fa void +.Fc .Ft long -.Fn jrand48 "unsigned short xseed[3]" -.Ft void -.Fn srand48 "long seed" +.Fo nrand48 +.Fa "unsigned short xsubi[3]" +.Fc .Ft "unsigned short *" -.Fn seed48 "unsigned short xseed[3]" +.Fo seed48 +.Fa "unsigned short seed16v[3]" +.Fc .Ft void -.Fn lcong48 "unsigned short p[7]" +.Fo srand48 +.Fa "long seedval" +.Fc .Sh DESCRIPTION The .Fn rand48 -family of functions generates pseudo-random numbers using a linear +family of functions generates pseudo-random numbers, using a linear congruential algorithm working on integers 48 bits in size. The particular formula employed is -r(n+1) = (a * r(n) + c) mod m -where the default values are -for the multiplicand a = 0xfdeece66d = 25214903917 and -the addend c = 0xb = 11. +r(n+1) = (a * r(n) + c) mod m. +The default value for the multiplicand `a' is 0xfdeece66d (25214903917). +The default value for the the addend `c' is 0xb (11). The modulo is always fixed at m = 2 ** 48. r(n) is called the seed of the random number generator. .Pp -For all the six generator routines described next, the first +For the six generator routines described next, the first computational step is to perform a single iteration of the algorithm. .Pp The @@ -124,7 +141,7 @@ .Fn drand48 , .Fn lrand48 , and -.Fn mrand48 +.Fn mrand48 , such that the 32 bits of the seed value are copied into the upper 32 bits of r(n), with the lower 16 bits of r(n) arbitrarily being set to 0x330e. Additionally, the constant multiplicand and addend of the algorithm are @@ -147,7 +164,7 @@ .Fn seed48 function returns a pointer to an array of 3 shorts which contains the old seed. -This array is statically allocated, thus its contents are lost after +This array is statically allocated; thus, its contents are lost after each new call to .Fn seed48 . .Pp