math.scalbn Method (Double, Int32)

mathscalbn Method (Double, Int32)

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 scalbn(
	double number,
	int exponent
)

Public Shared Function scalbn ( 
	number As Double,
	exponent As Integer
) As Double

public:
static double scalbn(
	double number, 
	int exponent
)

static member scalbn : 
        number : float * 
        exponent : int -> float

Parameters

number: Type: SystemDouble
A floating-point number.
exponent: Type: SystemInt32
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 scalbn(Double, Int32) is equivalent to ldexp(Double, Int32).

See scalbn in the C standard documentation.

Examples

C++

Copy

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

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

Assert.IsTrue(math.scalbn(1D, System.Int32.MaxValue) == System.Double.PositiveInfinity);
Assert.IsTrue(math.scalbn(1D, System.Int32.MinValue) == 0D);
Assert.IsTrue(math.scalbn(-1D, System.Int32.MaxValue) == System.Double.NegativeInfinity);
Assert.IsTrue(math.scalbn(-1D, System.Int32.MinValue) == -0D);

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

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

Assert.IsTrue(math.scalbn(1D, System.Int32.MaxValue) = System.Double.PositiveInfinity);
Assert.IsTrue(math.scalbn(1D, System.Int32.MinValue) = 0D);
Assert.IsTrue(math.scalbn(-1D, System.Int32.MaxValue) = System.Double.NegativeInfinity);
Assert.IsTrue(math.scalbn(-1D, System.Int32.MinValue) = -0D);

Reference

math Class

scalbn Overload

C Namespace