Initialize state with a default algorithm. This will be a compromise
between speed and randomness, and is recommended for applications with no
special requirements. Currently this is
Initialize state for a Mersenne Twister algorithm. This algorithm is fast and has good randomness properties.
(gmp_randstate_t state, const mpz_t a, unsigned long c, mp_bitcnt_t m2exp)¶
Initialize state with a linear congruential algorithm X = (a*X + c) mod 2^m2exp.
The low bits of X in this algorithm are not very random. The least significant bit will have a period no more than 2, and the second bit no more than 4, etc. For this reason only the high half of each X is actually used.
When a random number of more than m2exp/2 bits is to be generated, multiple iterations of the recurrence are used and the results concatenated.
(gmp_randstate_t state, mp_bitcnt_t size)¶
Initialize state for a linear congruential algorithm as per
gmp_randinit_lc_2exp. a, c and m2exp are selected
from a table, chosen so that size bits (or more) of each X will
be used, i.e. m2exp/2 >= size.
If successful the return value is non-zero. If size is bigger than the table data provides then the return value is zero. The maximum size currently supported is 128.
(gmp_randstate_t rop, gmp_randstate_t op)¶
Initialize rop with a copy of the algorithm and state from op.
(gmp_randstate_t state, gmp_randalg_t alg, …)¶
This function is obsolete.
Initialize state with an algorithm selected by alg. The only
GMP_RAND_ALG_LC, which is
described above. A third parameter of type
unsigned long is required,
this is the size for that function.
GMP_RAND_ALG_DEFAULT and 0
are the same as
gmp_randinit sets bits in the global variable
indicate an error.
GMP_ERROR_UNSUPPORTED_ARGUMENT if alg is
GMP_ERROR_INVALID_ARGUMENT if the size parameter
is too big. It may be noted this error reporting is not thread safe (a good
reason to use
Free all memory occupied by state.