math.scalbln Method (Double, Int64)

mathscalbln Method (Double, Int64)

Scales the specified floating-point number by 2^exponent.

Namespace: C
Assembly: C.math (in C.math.dll) Version: 1.0.0.0 (1.0.0.0)

Syntax

public static double scalbln(
	double number,
	long exponent
)

Public Shared Function scalbln ( 
	number As Double,
	exponent As Long
) As Double

public:
static double scalbln(
	double number, 
	long long exponent
)

static member scalbln : 
        number : float * 
        exponent : int64 -> float

Parameters

number: Type: SystemDouble
A floating-point number.
exponent: Type: SystemInt64
The exponent of the power of two.

Return Value

Type: Double
The value number * 2^exponent.

Remarks

Special values are treated as follows.

If number is ±0, it is returned.
If number is infinite, it is returned.
If exponent is 0, number is returned.
If number is NaN, NaN is returned.

The function scalbln(Double, Int64) is equivalent to ldexp(Double, Int32).

See scalbln in the C standard documentation.

Examples

C++

Copy

Assert.IsTrue(math.scalbln(0.8D, 4L) == 12.8D);
Assert.IsTrue(math.scalbln(-0.854375D, 5L) == -27.34D);
Assert.IsTrue(math.scalbln(1D, 0L) == 1D);

Assert.IsTrue(math.scalbln(math.DBL_MIN / 2D, 0L) == math.DBL_MIN / 2D);
Assert.IsTrue(math.scalbln(math.DBL_MIN / 2D, 1L) == math.DBL_MIN);
Assert.IsTrue(math.scalbln(math.DBL_MIN * 1.5D, -math.DBL_MANT_BITS) == 2D * math.DBL_DENORM_MIN);
Assert.IsTrue(math.scalbln(math.DBL_MIN * 1.5D, -math.DBL_MANT_BITS - 1) == math.DBL_DENORM_MIN);
Assert.IsTrue(math.scalbln(math.DBL_MIN * 1.25D, -math.DBL_MANT_BITS) == math.DBL_DENORM_MIN);
Assert.IsTrue(math.scalbln(math.DBL_MIN * 1.25D, -math.DBL_MANT_BITS - 1) == math.DBL_DENORM_MIN);

Assert.IsTrue(math.scalbln(1D, System.Int64.MaxValue) == System.Double.PositiveInfinity);
Assert.IsTrue(math.scalbln(1D, System.Int64.MinValue) == 0D);
Assert.IsTrue(math.scalbln(-1D, System.Int64.MaxValue) == System.Double.NegativeInfinity);
Assert.IsTrue(math.scalbln(-1D, System.Int64.MinValue) == -0D);

Assert.IsTrue(math.scalbln(0.8D, 4L) = 12.8D);
Assert.IsTrue(math.scalbln(-0.854375D, 5L) = -27.34D);
Assert.IsTrue(math.scalbln(1D, 0L) = 1D);

Assert.IsTrue(math.scalbln(math.DBL_MIN / 2D, 0L) = math.DBL_MIN / 2D);
Assert.IsTrue(math.scalbln(math.DBL_MIN / 2D, 1L) = math.DBL_MIN);
Assert.IsTrue(math.scalbln(math.DBL_MIN * 1.5D, -math.DBL_MANT_BITS) = 2D * math.DBL_DENORM_MIN);
Assert.IsTrue(math.scalbln(math.DBL_MIN * 1.5D, -math.DBL_MANT_BITS - 1) = math.DBL_DENORM_MIN);
Assert.IsTrue(math.scalbln(math.DBL_MIN * 1.25D, -math.DBL_MANT_BITS) = math.DBL_DENORM_MIN);
Assert.IsTrue(math.scalbln(math.DBL_MIN * 1.25D, -math.DBL_MANT_BITS - 1) = math.DBL_DENORM_MIN);

Assert.IsTrue(math.scalbln(1D, System.Int64.MaxValue) = System.Double.PositiveInfinity);
Assert.IsTrue(math.scalbln(1D, System.Int64.MinValue) = 0D);
Assert.IsTrue(math.scalbln(-1D, System.Int64.MaxValue) = System.Double.NegativeInfinity);
Assert.IsTrue(math.scalbln(-1D, System.Int64.MinValue) = -0D);

Reference

math Class

scalbln Overload

C Namespace