| mpfr_libmpfr_grandom Method |
Namespace: Math.Mpfr.Native
Assembly: Math.Mpfr.Native (in Math.Mpfr.Native.dll) Version: 1.0.0.0 (1.0.0.0)
Syntaxpublic static int mpfr_grandom( mpfr_t rop1, mpfr_t rop2, gmp_randstate_t state, mpfr_rnd_t rnd )
Parameters
- rop1
- Type: Math.Mpfr.Nativempfr_t
The first result operand floating-point number. - rop2
- Type: Math.Mpfr.Nativempfr_t
The second result operand floating-point number. - state
- Type: Math.Gmp.Nativegmp_randstate_t
The state of the random number generator. - rnd
- Type: Math.Mpfr.Nativempfr_rnd_t
The rounding direction.
Return Value
Type: Int32The combination of the ternary values is returned like with mpfr_sin_cos. If rop2 is a null pointer, the second ternary value is assumed to be 0 (note that the encoding of the only ternary value is not the same as the usual encoding for functions that return only one result). Otherwise the ternary value of a random number is always non-zero.
RemarksIf rop2 is a null pointer, then only one value is generated and stored in rop1.
The floating-point number rop1 (and rop2) can be seen as if a random real number were generated according to the standard normal Gaussian distribution and then rounded in the direction rnd.
The gmp_randstate_t argument should be created using the GMP gmp_randinit function (see the GMP manual).
Note: the note for mpfr_urandomb holds too. In addition, the exponent range and the rounding mode might have a side effect on the next random state.
Note: mpfr_nrandom(mpfr_t, gmp_randstate_t, mpfr_rnd_t) is much more efficient than mpfr_grandom(mpfr_t, mpfr_t, gmp_randstate_t, mpfr_rnd_t), especially for large precision. Thus mpfr_grandom(mpfr_t, mpfr_t, gmp_randstate_t, mpfr_rnd_t) is marked as deprecated and will be removed in a future release.
Examples// Create, initialize, and seed a new random number generator. gmp_randstate_t state = new gmp_randstate_t(); gmp_lib.gmp_randinit_mt(state); gmp_lib.gmp_randseed_ui(state, 100000U); // Create and initialize a new floating-point number rop1. mpfr_t rop1 = new mpfr_t(); mpfr_lib.mpfr_init2(rop1, 64U); // Create and initialize a new floating-point number rop2. mpfr_t rop2 = new mpfr_t(); mpfr_lib.mpfr_init2(rop2, 64U); // Generate two Gaussian random floating-point numbers. Assert.IsTrue(mpfr_lib.mpfr_grandom(rop1, rop2, state, mpfr_rnd_t.MPFR_RNDN) == 10); // Generate one Gaussian random floating-point number. Assert.IsTrue(mpfr_lib.mpfr_grandom(rop1, null, state, mpfr_rnd_t.MPFR_RNDN) == 1); // Free all memory occupied by state, rop1, and rop2. gmp_lib.gmp_randclear(state); mpfr_lib.mpfr_clears(rop1, rop2, null);
See Also