URCW 3CW "05 January 2007" "mathcw-1.00"

Table of contents


NAME

urcwf, urcw, urcwl, urcww, urcwq, urcwll, urcwdf, urcwd, urcwdl, urcwdll - pseudorandom number in (0,1)

SYNOPSIS

cc [ flags ] -I/usr/local/include file(s) -L/usr/local/lib -lmcw [ ... ]

#include <mathcw.h>

extern float urcwf (void);

extern double urcw (void);

extern long double urcwl (void);

extern __float80 urcww (void);

extern __float128 urcwq (void);

extern long_long_double urcwll (void);

extern decimal_float urcwdf (void);

extern decimal_double urcwd (void);

extern decimal_long_double urcwdl (void);

extern decimal_long_long_double urcwdll (void);

NB: Functions with prototypes containing underscores in type names may be available only with certain extended compilers.


DESCRIPTION

Return a pseudorandom number uniformly distributed on (0,1) (that is, 0 < urcw() < 1).

This function is equivalent to urcw4(3CW).

The generator state is kept internally to simplify the user interface. However, this is not safe in multithreaded programs. For them, use the reentrant generator routines instead, identified by the suffix _r. The reentrant routines also make possible families of independent generators within the same program.

The generator is Marsaglia's KISS generator, which has a long period of about 2**123 (approximately 10**37), and has passed several difficult tests of randomness, including Marsaglia's Diehard Battery test suite, and the Marsaglia/Tsang tuftest suite.

The double functions sample the 32-bit integer generator twice, the long double functions sample it four times, and the long long double functions sample it eight times,

When precision permits, the decimal floating-point functions use the corresponding binary generator, and then convert that result to decimal. Otherwise, they convert several samples of the integer generator to decimal floating-point with suitable scaling.


RETURN VALUES

The pseudorandom number.

ERRORS

None.

SEE ALSO

ercw(3CW), ercw_r(3CW), gscw(3CW), incw_r(3CW), llrancw(3CW), llrancw_r(3CW), llrincw(3CW), llrincw_r(3CW), lrancw(3CW), lrancw_r(3CW), lrcw(3CW), lrcw_r(3CW), lrincw(3CW), lrincw_r(3CW), mscw(3CW), nrcw(3CW), nrcw_r(3CW), sccw(3CW), sscw(3CW), urcw1(3CW), urcw1_r(3CW), urcw2(3CW), urcw2_r(3CW), urcw3(3CW), urcw3_r(3CW), urcw4(3CW), urcw4_r(3CW), urcw_r(3CW), vercw(3CW), vercw_r(3CW), vllrancw(3CW), vllrancw_r(3CW), vllrincw(3CW), vllrincw_r(3CW), vlrancw(3CW), vlrancw_r(3CW), vlrcw(3CW), vlrcw_r(3CW), vlrincw(3CW), vlrincw_r(3CW), vnrcw(3CW), vnrcw_r(3CW), vurcw(3CW), vurcw1(3CW), vurcw1_r(3CW), vurcw2(3CW), vurcw2_r(3CW), vurcw3(3CW), vurcw3_r(3CW), vurcw4(3CW), vurcw4_r(3CW), vurcw_r(3CW).