mpfr_lib.mpfr_frexp Method (mpfr_exp_t, mpfr_t, mpfr_t, mpfr_rnd

mpfr_libmpfr_frexp Method (mpfr_exp_t, mpfr_t, mpfr_t, mpfr_rnd_t)

Set exp and y such that 0.5 ≤ abs(y) < 1 and y * 2^exp = x rounded to the precision of y, using the given rounding mode.

Namespace: Math.Mpfr.Native
Assembly: Math.Mpfr.Native (in Math.Mpfr.Native.dll) Version: 1.0.0.0 (1.0.0.0)

Syntax

C++

Copy

public static int mpfr_frexp(
	ref mpfr_exp_t exp,
	mpfr_t y,
	mpfr_t x,
	mpfr_rnd_t rnd
)

Public Shared Function mpfr_frexp ( 
	ByRef exp As mpfr_exp_t,
	y As mpfr_t,
	x As mpfr_t,
	rnd As mpfr_rnd_t
) As Integer

public:
static int mpfr_frexp(
	mpfr_exp_t% exp, 
	mpfr_t^ y, 
	mpfr_t^ x, 
	mpfr_rnd_t rnd
)

static member mpfr_frexp : 
        exp : mpfr_exp_t byref * 
        y : mpfr_t * 
        x : mpfr_t * 
        rnd : mpfr_rnd_t -> int

Parameters

exp: Type: Math.Mpfr.Nativempfr_exp_t
The returned exponent.
y: Type: Math.Mpfr.Nativempfr_t
The returned significand.
x: Type: Math.Mpfr.Nativempfr_t
The operand floating-point number.
rnd: Type: Math.Mpfr.Nativempfr_rnd_t
The rounding direction.

Return Value

Type: Int32
Return zero, a positive, or a negative value if y is respectively equal to, greater than, or lower than the exact result. See GNU MPFR - Rounding Modes for details.

Remarks

If x is zero, then y is set to a zero of the same sign and exp is set to 0. If x is NaN or an infinity, then y is set to the same value and exp is undefined.

Examples

C++

Copy

// Create, initialize, and set a new floating-point number x to 100.
mpfr_t x = new mpfr_t();
mpfr_lib.mpfr_init2(x, 64U);
Assert.IsTrue(mpfr_lib.mpfr_set_si(x, 100, mpfr_rnd_t.MPFR_RNDN) == 0);

// Create, initialize, and set a new floating-point number y.
mpfr_t y = new mpfr_t();
mpfr_lib.mpfr_init2(y, 64U);

// Initialize exponent.
mpfr_exp_t exp = 0;

// Find y and exp such that x = y * 2^exp where y in [0.5, 1).
Assert.IsTrue(mpfr_lib.mpfr_frexp(ref exp, y, x, mpfr_rnd_t.MPFR_RNDN) == 0);

// Assert the value of exp and y.
Assert.IsTrue(y.ToString() == "0.781250000000000000000e0" && exp == 7);

// Release unmanaged memory allocated for x, and y.
mpfr_lib.mpfr_clears(x, y, null);

' Create, initialize, and set a new floating-point number x to 100.
Dim x As mpfr_t = New mpfr_t()
mpfr_lib.mpfr_init2(x, 64U)
Assert.IsTrue(mpfr_lib.mpfr_set_si(x, 100, mpfr_rnd_t.MPFR_RNDN) = 0)

' Create, initialize, and set a new floating-point number y.
Dim y As mpfr_t = New mpfr_t()
mpfr_lib.mpfr_init2(y, 64U)

' Initialize exponent.
Dim exp As mpfr_exp_t = 0 

' Find y and exp such that x = y * 2^exp where y in [0.5, 1).
Assert.IsTrue(mpfr_lib.mpfr_frexp( exp,y,x,mpfr_rnd_t.MPFR_RNDN)  =  0)

' Assert the value of exp and y.
Assert.IsTrue(y.ToString() = "0.781250000000000000000e0" AndAlso exp = 7)

' Release unmanaged memory allocated for x, and y.
mpfr_lib.mpfr_clears(x, y, Nothing)

Parameters

Return Value

Reference