math32

README

math32

A float32 version of Go's math package. The majority of code in this library is a thin float32 wrapper over the results of the math package that comes in the standard lib.

The original code is lifted from the Go standard library which is governed by a BSD-style licence which can be found here: https://golang.org/LICENSE.

Documentation

Index

• Constants
• func Abs(x float32) float32
• func Ceil(x float32) float32
• func Copysign(x, y float32) float32
• func Dim(x, y float32) float32
• func Exp(x float32) float32
• func Float32bits(f float32) uint32
• func Float32frombits(b uint32) float32
• func Floor(x float32) float32
• func Frexp(f float32) (frac float32, exp int)
• func Inf(sign int) float32
• func IsInf(f float32, sign int) bool
• func IsNaN(f float32) (is bool)
• func Ldexp(frac float32, exp int) float32
• func Log(x float32) float32
• func Max(x, y float32) float32
• func Min(x, y float32) float32
• func Modf(f float32) (int float32, frac float32)
• func NaN() float32
• func Pow(x, y float32) float32
• func Signbit(x float32) bool
• func Sqrt(x float32) float32
• func Tanh(x float32) float32
• func Trunc(x float32) float32

Constants

const (
	E   = float32(2.71828182845904523536028747135266249775724709369995957496696763) // http://oeis.org/A001113
	Pi  = float32(3.14159265358979323846264338327950288419716939937510582097494459) // http://oeis.org/A000796
	Phi = float32(1.61803398874989484820458683436563811772030917980576286213544862) // http://oeis.org/A001622

	Sqrt2   = float32(1.41421356237309504880168872420969807856967187537694807317667974) // http://oeis.org/A002193
	SqrtE   = float32(1.64872127070012814684865078781416357165377610071014801157507931) // http://oeis.org/A019774
	SqrtPi  = float32(1.77245385090551602729816748334114518279754945612238712821380779) // http://oeis.org/A002161
	SqrtPhi = float32(1.27201964951406896425242246173749149171560804184009624861664038) // http://oeis.org/A139339

	Ln2    = float32(0.693147180559945309417232121458176568075500134360255254120680009) // http://oeis.org/A002162
	Log2E  = float32(1 / Ln2)
	Ln10   = float32(2.30258509299404568401799145468436420760110148862877297603332790) // http://oeis.org/A002392
	Log10E = float32(1 / Ln10)
)

Mathematical constants.

const (
	MaxFloat32             = 3.40282346638528859811704183484516925440e+38  // 2**127 * (2**24 - 1) / 2**23
	SmallestNonzeroFloat32 = 1.401298464324817070923729583289916131280e-45 // 1 / 2**(127 - 1 + 23)
)

Floating-point limit values. Max is the largest finite value representable by the type. SmallestNonzero is the smallest positive, non-zero value representable by the type.

const (
	MaxInt8   = 1<<7 - 1
	MinInt8   = -1 << 7
	MaxInt16  = 1<<15 - 1
	MinInt16  = -1 << 15
	MaxInt32  = 1<<31 - 1
	MinInt32  = -1 << 31
	MaxInt64  = 1<<63 - 1
	MinInt64  = -1 << 63
	MaxUint8  = 1<<8 - 1
	MaxUint16 = 1<<16 - 1
	MaxUint32 = 1<<32 - 1
	MaxUint64 = 1<<64 - 1
)

Integer limit values.

Functions

func Abs

func Abs(x float32) float32

Abs returns the absolute value of x.

Special cases are:

Abs(±Inf) = +Inf
Abs(NaN) = NaN

func Ceil

func Ceil(x float32) float32

Ceil returns the least integer value greater than or equal to x.

Special cases are:

Ceil(±0) = ±0
Ceil(±Inf) = ±Inf
Ceil(NaN) = NaN

func Copysign

func Copysign(x, y float32) float32

Copysign returns a value with the magnitude of x and the sign of y.

func Dim

func Dim(x, y float32) float32

Dim returns the maximum of x-y or 0.

Special cases are:

Dim(+Inf, +Inf) = NaN
Dim(-Inf, -Inf) = NaN
Dim(x, NaN) = Dim(NaN, x) = NaN

func Exp

func Exp(x float32) float32

Exp returns e**x, the base-e exponential of x.

func Float32bits

func Float32bits(f float32) uint32

Float32bits returns the IEEE 754 binary representation of f.

func Float32frombits

func Float32frombits(b uint32) float32

Float32frombits returns the floating point number corresponding to the IEEE 754 binary representation b.

func Floor

func Floor(x float32) float32

Floor returns the greatest integer value less than or equal to x.

Special cases are:

Floor(±0) = ±0
Floor(±Inf) = ±Inf
Floor(NaN) = NaN

func Frexp

func Frexp(f float32) (frac float32, exp int)

Frexp breaks f into a normalized fraction and an integral power of two. It returns frac and exp satisfying f == frac × 2**exp, with the absolute value of frac in the interval [½, 1).

Special cases are:

Frexp(±0) = ±0, 0
Frexp(±Inf) = ±Inf, 0
Frexp(NaN) = NaN, 0

func Inf

func Inf(sign int) float32

Inf returns positive infinity if sign >= 0, negative infinity if sign < 0.

func IsInf

func IsInf(f float32, sign int) bool

IsInf reports whether f is an infinity, according to sign. If sign > 0, IsInf reports whether f is positive infinity. If sign < 0, IsInf reports whether f is negative infinity. If sign == 0, IsInf reports whether f is either infinity.

func IsNaN

func IsNaN(f float32) (is bool)

IsNaN reports whether f is an IEEE 754 “not-a-number” value.

func Ldexp

func Ldexp(frac float32, exp int) float32

Ldexp is the inverse of Frexp. It returns frac × 2**exp.

Special cases are:

Ldexp(±0, exp) = ±0
Ldexp(±Inf, exp) = ±Inf
Ldexp(NaN, exp) = NaN

func Log

func Log(x float32) float32

Log returns the natural logarithm of x.

Special cases are:

Log(+Inf) = +Inf
Log(0) = -Inf
Log(x < 0) = NaN
Log(NaN) = NaN

func Max

func Max(x, y float32) float32

Max returns the larger of x or y.

Special cases are:

Max(x, +Inf) = Max(+Inf, x) = +Inf
Max(x, NaN) = Max(NaN, x) = NaN
Max(+0, ±0) = Max(±0, +0) = +0
Max(-0, -0) = -0

func Min

func Min(x, y float32) float32

Min returns the smaller of x or y.

Special cases are:

Min(x, -Inf) = Min(-Inf, x) = -Inf
Min(x, NaN) = Min(NaN, x) = NaN
Min(-0, ±0) = Min(±0, -0) = -0

func Modf

func Modf(f float32) (int float32, frac float32)

Modf returns integer and fractional floating-point numbers that sum to f. Both values have the same sign as f.

Special cases are:

Modf(±Inf) = ±Inf, NaN
Modf(NaN) = NaN, NaN

func NaN

func NaN() float32

NaN returns an IEEE 754 “not-a-number” value.

func Pow

func Pow(x, y float32) float32

Pow returns x**y, the base-x exponential of y.

Special cases are (in order):

Pow(x, ±0) = 1 for any x
Pow(1, y) = 1 for any y
Pow(x, 1) = x for any x
Pow(NaN, y) = NaN
Pow(x, NaN) = NaN
Pow(±0, y) = ±Inf for y an odd integer < 0
Pow(±0, -Inf) = +Inf
Pow(±0, +Inf) = +0
Pow(±0, y) = +Inf for finite y < 0 and not an odd integer
Pow(±0, y) = ±0 for y an odd integer > 0
Pow(±0, y) = +0 for finite y > 0 and not an odd integer
Pow(-1, ±Inf) = 1
Pow(x, +Inf) = +Inf for |x| > 1
Pow(x, -Inf) = +0 for |x| > 1
Pow(x, +Inf) = +0 for |x| < 1
Pow(x, -Inf) = +Inf for |x| < 1
Pow(+Inf, y) = +Inf for y > 0
Pow(+Inf, y) = +0 for y < 0
Pow(-Inf, y) = Pow(-0, -y)
Pow(x, y) = NaN for finite x < 0 and finite non-integer y

func Signbit

func Signbit(x float32) bool

Signbit returns true if x is negative or negative zero.

func Sqrt

func Sqrt(x float32) float32

Sqrt returns the square root of x.

func Tanh

func Tanh(x float32) float32

Tanh returns the hyperbolic tangent of x.

func Trunc

func Trunc(x float32) float32

Trunc returns the integer value of x.

Special cases are:

Trunc(±0) = ±0
Trunc(±Inf) = ±Inf
Trunc(NaN) = NaN