The C++ class interface to the GMP random number functions uses
gmp_randclass to hold an algorithm selection and current state, as per
gmp_randstate_t.
(void (*randinit) (gmp_randstate_t, …), …) ¶Construct a gmp_randclass, using a call to the given randinit
function (see Random State Initialization). The arguments expected are
the same as randinit, but with mpz_class instead of mpz_t.
For example,
gmp_randclass r1 (gmp_randinit_default); gmp_randclass r2 (gmp_randinit_lc_2exp_size, 32); gmp_randclass r3 (gmp_randinit_lc_2exp, a, c, m2exp); gmp_randclass r4 (gmp_randinit_mt);
gmp_randinit_lc_2exp_size will fail if the size requested is too big,
an std::length_error exception is thrown in that case.
(gmp_randalg_t alg, …) ¶Construct a gmp_randclass using the same parameters as
gmp_randinit (see Random State Initialization). This function is
obsolete and the above randinit style should be preferred.
void gmp_randclass::seed (unsigned long int s) ¶void gmp_randclass::seed (mpz_class s) ¶Seed a random number generator. See see Random Number Functions, for how to choose a good seed.
mpz_class gmp_randclass::get_z_bits (mp_bitcnt_t bits) ¶mpz_class gmp_randclass::get_z_bits (mpz_class bits) ¶Generate a random integer with a specified number of bits.
mpz_class gmp_randclass::get_z_range (mpz_class n) ¶Generate a random integer in the range 0 to n-1 inclusive.
mpf_class gmp_randclass::get_f () ¶mpf_class gmp_randclass::get_f (mp_bitcnt_t prec) ¶Generate a random float f in the range 0 <= f < 1. f will be to prec bits precision, or if prec is not given then to the precision of the destination. For example,
gmp_randclass r; ... mpf_class f (0, 512); // 512 bits precision f = r.get_f(); // random number, 512 bits