cc [ flags ] -I/usr/local/include file(s) -L/usr/local/lib -lmcw [ ... ] #include <mathcw.h> extern float urcw2f_r (randcw_state_t state); extern double urcw2_r (randcw_state_t state); extern long double urcw2l_r (randcw_state_t state); extern __float80 urcw2w_r (randcw_state_t state); extern __float128 urcw2q_r (randcw_state_t state); extern long_long_double urcw2ll_r (randcw_state_t state); extern decimal_float urcw2df_r (randcw_state_t state); extern decimal_double urcw2d_r (randcw_state_t state); extern decimal_long_double urcw2dl_r (randcw_state_t state); extern decimal_long_long_double urcw2dll_r (randcw_state_t state);
NB: Functions with prototypes containing underscores in type names may be available only with certain extended compilers.
The generator state is keep externally in the state argument, a vector of four UINT_LEAST32_T values, most conveniently initialized with incw_r(). This makes the functions thread safe, and allows creation of a practically-unlimited number of independent families of generators, each with its own state.
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.