mpfr_lib.mpfr_lgamma Method (mpfr_t, ptr(Int32), mpfr_t, mpfr_rnd

mpfr_libmpfr_lgamma Method (mpfr_t, ptrInt32, mpfr_t, mpfr_rnd_t)

Set rop to the value of the logarithm of the absolute value of the Gamma function on op rounded in the direction rnd.

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

Syntax

public static int mpfr_lgamma(
	mpfr_t rop,
	ptr<int> signp,
	mpfr_t op,
	mpfr_rnd_t rnd
)

Public Shared Function mpfr_lgamma ( 
	rop As mpfr_t,
	signp As ptr(Of Integer),
	op As mpfr_t,
	rnd As mpfr_rnd_t
) As Integer

public:
static int mpfr_lgamma(
	mpfr_t^ rop, 
	ptr<int>^ signp, 
	mpfr_t^ op, 
	mpfr_rnd_t rnd
)

static member mpfr_lgamma : 
        rop : mpfr_t * 
        signp : ptr<int> * 
        op : mpfr_t * 
        rnd : mpfr_rnd_t -> int

Parameters

rop: Type: Math.Mpfr.Nativempfr_t
The result floating-point number.
signp: Type: Math.Gmp.NativeptrInt32
The returned sign.
op: 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 rop is respectively equal to, greater than, or lower than the exact result. See GNU MPFR - Rounding Modes for details.

Remarks

The sign (1 or -1) of Gamma(op) is returned in the object pointed to by signp. When op is 1 or 2, set rop to +0 (in all rounding modes). When op is an infinity or a nonpositive integer, set rop to +Inf. When op is NaN, -Inf or a negative integer, signp is undefined, and when op is ±0, signp is the sign of the zero.

Examples

C++

Copy

// Create, initialize, and set a new floating-point number op to 10.4.
mpfr_t op = new mpfr_t();
mpfr_lib.mpfr_init2(op, 64U);
Assert.IsTrue(mpfr_lib.mpfr_set_d(op, 10.4, mpfr_rnd_t.MPFR_RNDN) == 0);

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

// Set rop to log(|Gamma(op)|).
ptr<int> sign = new ptr<int>(0);
Assert.IsTrue(mpfr_lib.mpfr_lgamma(rop, sign, op, mpfr_rnd_t.MPFR_RNDN) == -1);

// Assert the value of rop and sign.
Assert.IsTrue(rop.ToString() == "0.137108263716202786516e2" && sign.Value == 1);

// Release unmanaged memory allocated for rop and op.
mpfr_lib.mpfr_clears(rop, op, null);

' Create, initialize, and set a new floating-point number op to 10.4.
Dim op As mpfr_t = New mpfr_t()
mpfr_lib.mpfr_init2(op, 64U)
Assert.IsTrue(mpfr_lib.mpfr_set_d(op, 10.4, mpfr_rnd_t.MPFR_RNDN) = 0)

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

' Set rop to log(|Gamma(op)|).
Dim sign As ptr(Of int) =  New ptr(Of int)(0)
Assert.IsTrue(mpfr_lib.mpfr_lgamma(rop, sign, op, mpfr_rnd_t.MPFR_RNDN) = -1)

' Assert the value of rop and sign.
Assert.IsTrue(rop.ToString() = "0.137108263716202786516e2" AndAlso sign.Value = 1)

' Release unmanaged memory allocated for rop and op.
mpfr_lib.mpfr_clears(rop, op, Nothing)

Parameters

Return Value

Reference