Professor George Marsaglia's high quality inline random number generators. The following code is adapted from his news posting to sci.stat.math on 1999/01/21. The author can be contacted at geo@stat.fsu.edu (I contacted him twice in the past and received a reply). Professor Marsaglia gave the following description of the generators used below:
Any one of KISS, MWC, FIB, LFIB4, SWB, SHR3, or CONG can be used in an expression to provide a random 32-bit integer.
The KISS generator, (Keep It Simple Stupid), is designed to combine the two multiply-with-carry generators in MWC with the 3-shift register SHR3 and the congruential generator CONG, using addition and exclusive-or. Period about 2^123. It is one of my favorite generators.
The MWC generator concatenates two 16-bit multiply- with-carry generators, x(n)=36969x(n-1)+carry, y(n)=18000y(n-1)+carry mod 2^16, has period about 2^60 and seems to pass all tests of randomness. A favorite stand-alone generator---faster than KISS, which contains it.
SHR3 is a 3-shift-register generator with period 2^32-1. It uses y(n)=y(n-1)(I+L^17)(I+R^13)(I+L^5), with the y's viewed as binary vectors, L the 32x32 binary matrix that shifts a vector left 1, and R its transpose. SHR3 seems to pass all except those related to the binary rank test, since 32 successive values, as binary vectors, must be linearly independent, while 32 successive truly random 32-bit integers, viewed as binary vectors, will be linearly independent only about 29% of the time.
CONG is a congruential generator with the widely used 69069 multiplier: x(n)=69069x(n-1)+1234567. It has period 2^32. The leading half of its 32 bits seem to pass tests, but bits in the last half are too regular.
//===========================================================================
// kissRandom() - return a random 32 bit unsigned int
//===========================================================================
unsigned int kissRandom(void)
{
//
// WMC
//
#define RAND_ZNEW (z=36969*(z&65535)+(z>>16))
#define RAND_WNEW (w=18000*(w&65535)+(w>>16))
#define RAND_MWC ((RAND_ZNEW<<16)+RAND_WNEW)
static unsigned long z=362436069, w=521288629;
//
// SHR3
//
#define RAND_SHR3 (jsr=jsr^(jsr<<17), \
jsr=jsr^(jsr>>13), \
jsr=jsr^(jsr<<5))
static unsigned long jsr=123456789;
//
// CONG
//
#define RAND_CONG (jcong=69069*jcong+1234567)
static unsigned long jcong=380116160;
//
// KISS
//
#define RAND_KISS ((RAND_MWC^RAND_CONG)+RAND_SHR3)
return RAND_KISS;
#undef RAND_ZNEW
#undef RAND_WNEW
#undef RAND_MWC
#undef RAND_SHR3
#undef RAND_CONG
#undef RAND_KISS
}