math

func Abs ¶

func Abs(x float64) float64

Abs returns the absolute value of x.

Special cases are:

Abs(±Inf) = +Inf Abs(NaN) = NaN 

 package main import (	"fmt"	"math" ) func main() {	x := math.Abs(-2)	fmt.Printf("%.1f\n", x)	y := math.Abs(2)	fmt.Printf("%.1f\n", y) } 

Output: 2.0 2.0 

func Acos ¶

func Acos(x float64) float64

Acos returns the arccosine, in radians, of x.

Special case is:

Acos(x) = NaN if x < -1 or x > 1 

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.2f", math.Acos(1)) } 

Output: 0.00 

func Acosh ¶

func Acosh(x float64) float64

Acosh returns the inverse hyperbolic cosine of x.

Special cases are:

Acosh(+Inf) = +Inf Acosh(x) = NaN if x < 1 Acosh(NaN) = NaN 

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.2f", math.Acosh(1)) } 

Output: 0.00 

func Asin ¶

func Asin(x float64) float64

Asin returns the arcsine, in radians, of x.

Special cases are:

Asin(±0) = ±0 Asin(x) = NaN if x < -1 or x > 1 

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.2f", math.Asin(0)) } 

Output: 0.00 

func Asinh ¶

func Asinh(x float64) float64

Asinh returns the inverse hyperbolic sine of x.

Special cases are:

Asinh(±0) = ±0 Asinh(±Inf) = ±Inf Asinh(NaN) = NaN 

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.2f", math.Asinh(0)) } 

Output: 0.00 

func Atan ¶

func Atan(x float64) float64

Atan returns the arctangent, in radians, of x.

Special cases are:

Atan(±0) = ±0 Atan(±Inf) = ±Pi/2 

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.2f", math.Atan(0)) } 

Output: 0.00 

func Atan2 ¶

func Atan2(y, x float64) float64

Atan2 returns the arc tangent of y/x, using the signs of the two to determine the quadrant of the return value.

Special cases are (in order):

Atan2(y, NaN) = NaN Atan2(NaN, x) = NaN Atan2(+0, x>=0) = +0 Atan2(-0, x>=0) = -0 Atan2(+0, x<=-0) = +Pi Atan2(-0, x<=-0) = -Pi Atan2(y>0, 0) = +Pi/2 Atan2(y<0, 0) = -Pi/2 Atan2(+Inf, +Inf) = +Pi/4 Atan2(-Inf, +Inf) = -Pi/4 Atan2(+Inf, -Inf) = 3Pi/4 Atan2(-Inf, -Inf) = -3Pi/4 Atan2(y, +Inf) = 0 Atan2(y>0, -Inf) = +Pi Atan2(y<0, -Inf) = -Pi Atan2(+Inf, x) = +Pi/2 Atan2(-Inf, x) = -Pi/2 

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.2f", math.Atan2(0, 0)) } 

Output: 0.00 

func Atanh ¶

func Atanh(x float64) float64

Atanh returns the inverse hyperbolic tangent of x.

Special cases are:

Atanh(1) = +Inf Atanh(±0) = ±0 Atanh(-1) = -Inf Atanh(x) = NaN if x < -1 or x > 1 Atanh(NaN) = NaN 

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.2f", math.Atanh(0)) } 

Output: 0.00 

func Cbrt ¶

func Cbrt(x float64) float64

Cbrt returns the cube root of x.

Special cases are:

Cbrt(±0) = ±0 Cbrt(±Inf) = ±Inf Cbrt(NaN) = NaN 

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.2f\n", math.Cbrt(8))	fmt.Printf("%.2f\n", math.Cbrt(27)) } 

Output: 2.00 3.00 

func Ceil ¶

func Ceil(x float64) float64

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

Special cases are:

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

 package main import (	"fmt"	"math" ) func main() {	c := math.Ceil(1.49)	fmt.Printf("%.1f", c) } 

Output: 2.0 

func Copysign ¶

func Copysign(f, sign float64) float64

Copysign returns a value with the magnitude of f and the sign of sign.

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.2f", math.Copysign(3.2, -1)) } 

Output: -3.20 

func Cos ¶

func Cos(x float64) float64

Cos returns the cosine of the radian argument x.

Special cases are:

Cos(±Inf) = NaN Cos(NaN) = NaN 

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.2f", math.Cos(math.Pi/2)) } 

Output: 0.00 

func Cosh ¶

func Cosh(x float64) float64

Cosh returns the hyperbolic cosine of x.

Special cases are:

Cosh(±0) = 1 Cosh(±Inf) = +Inf Cosh(NaN) = NaN 

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.2f", math.Cosh(0)) } 

Output: 1.00 

func Dim ¶

func Dim(x, y float64) float64

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 

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.2f\n", math.Dim(4, -2))	fmt.Printf("%.2f\n", math.Dim(-4, 2)) } 

Output: 6.00 0.00 

func Erf ¶

func Erf(x float64) float64

Erf returns the error function of x.

Special cases are:

Erf(+Inf) = 1 Erf(-Inf) = -1 Erf(NaN) = NaN 

func Erfc ¶

func Erfc(x float64) float64

Erfc returns the complementary error function of x.

Special cases are:

Erfc(+Inf) = 0 Erfc(-Inf) = 2 Erfc(NaN) = NaN 

func Erfcinv ¶ added in go1.10

func Erfcinv(x float64) float64

Erfcinv returns the inverse of Erfc(x).

Special cases are:

Erfcinv(0) = +Inf Erfcinv(2) = -Inf Erfcinv(x) = NaN if x < 0 or x > 2 Erfcinv(NaN) = NaN 

func Erfinv ¶ added in go1.10

func Erfinv(x float64) float64

Erfinv returns the inverse error function of x.

Special cases are:

Erfinv(1) = +Inf Erfinv(-1) = -Inf Erfinv(x) = NaN if x < -1 or x > 1 Erfinv(NaN) = NaN 

func Exp ¶

func Exp(x float64) float64

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

Special cases are:

Exp(+Inf) = +Inf Exp(NaN) = NaN 

Very large values overflow to 0 or +Inf. Very small values underflow to 1.

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.2f\n", math.Exp(1))	fmt.Printf("%.2f\n", math.Exp(2))	fmt.Printf("%.2f\n", math.Exp(-1)) } 

Output: 2.72 7.39 0.37 

func Exp2 ¶

func Exp2(x float64) float64

Exp2 returns 2**x, the base-2 exponential of x.

Special cases are the same as Exp.

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.2f\n", math.Exp2(1))	fmt.Printf("%.2f\n", math.Exp2(-3)) } 

Output: 2.00 0.12 

func Expm1 ¶

func Expm1(x float64) float64

Expm1 returns e**x - 1, the base-e exponential of x minus 1. It is more accurate than Exp(x) - 1 when x is near zero.

Special cases are:

Expm1(+Inf) = +Inf Expm1(-Inf) = -1 Expm1(NaN) = NaN 

Very large values overflow to -1 or +Inf.

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.6f\n", math.Expm1(0.01))	fmt.Printf("%.6f\n", math.Expm1(-1)) } 

Output: 0.010050 -0.632121 

func FMA ¶ added in go1.14

func FMA(x, y, z float64) float64

FMA returns x * y + z, computed with only one rounding. (That is, FMA returns the fused multiply-add of x, y, and z.)

func Float32bits ¶

func Float32bits(f float32) uint32

Float32bits returns the IEEE 754 binary representation of f, with the sign bit of f and the result in the same bit position. Float32bits(Float32frombits(x)) == x.

func Float32frombits ¶

func Float32frombits(b uint32) float32

Float32frombits returns the floating-point number corresponding to the IEEE 754 binary representation b, with the sign bit of b and the result in the same bit position. Float32frombits(Float32bits(x)) == x.

func Float64bits ¶

func Float64bits(f float64) uint64

Float64bits returns the IEEE 754 binary representation of f, with the sign bit of f and the result in the same bit position, and Float64bits(Float64frombits(x)) == x.

func Float64frombits ¶

func Float64frombits(b uint64) float64

Float64frombits returns the floating-point number corresponding to the IEEE 754 binary representation b, with the sign bit of b and the result in the same bit position. Float64frombits(Float64bits(x)) == x.

func Floor ¶

func Floor(x float64) float64

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

Special cases are:

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

 package main import (	"fmt"	"math" ) func main() {	c := math.Floor(1.51)	fmt.Printf("%.1f", c) } 

Output: 1.0 

func Frexp ¶

func Frexp(f float64) (frac float64, 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 Gamma ¶

func Gamma(x float64) float64

Gamma returns the Gamma function of x.

Special cases are:

Gamma(+Inf) = +Inf Gamma(+0) = +Inf Gamma(-0) = -Inf Gamma(x) = NaN for integer x < 0 Gamma(-Inf) = NaN Gamma(NaN) = NaN 

func Hypot ¶

func Hypot(p, q float64) float64

Hypot returns Sqrt(p*p + q*q), taking care to avoid unnecessary overflow and underflow.

Special cases are:

Hypot(±Inf, q) = +Inf Hypot(p, ±Inf) = +Inf Hypot(NaN, q) = NaN Hypot(p, NaN) = NaN 

func Ilogb ¶

func Ilogb(x float64) int

Ilogb returns the binary exponent of x as an integer.

Special cases are:

Ilogb(±Inf) = MaxInt32 Ilogb(0) = MinInt32 Ilogb(NaN) = MaxInt32 

func Inf ¶

func Inf(sign int) float64

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

func IsInf ¶

func IsInf(f float64, 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 float64) (is bool)

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

func J0 ¶

func J0(x float64) float64

J0 returns the order-zero Bessel function of the first kind.

Special cases are:

J0(±Inf) = 0 J0(0) = 1 J0(NaN) = NaN 

func J1 ¶

func J1(x float64) float64

J1 returns the order-one Bessel function of the first kind.

Special cases are:

J1(±Inf) = 0 J1(NaN) = NaN 

func Jn ¶

func Jn(n int, x float64) float64

Jn returns the order-n Bessel function of the first kind.

Special cases are:

Jn(n, ±Inf) = 0 Jn(n, NaN) = NaN 

func Ldexp ¶

func Ldexp(frac float64, exp int) float64

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 Lgamma ¶

func Lgamma(x float64) (lgamma float64, sign int)

Lgamma returns the natural logarithm and sign (-1 or +1) of Gamma(x).

Special cases are:

Lgamma(+Inf) = +Inf Lgamma(0) = +Inf Lgamma(-integer) = +Inf Lgamma(-Inf) = -Inf Lgamma(NaN) = NaN 

func Log ¶

func Log(x float64) float64

Log returns the natural logarithm of x.

Special cases are:

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

 package main import (	"fmt"	"math" ) func main() {	x := math.Log(1)	fmt.Printf("%.1f\n", x)	y := math.Log(2.7183)	fmt.Printf("%.1f\n", y) } 

Output: 0.0 1.0 

func Log10 ¶

func Log10(x float64) float64

Log10 returns the decimal logarithm of x. The special cases are the same as for Log.

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.1f", math.Log10(100)) } 

Output: 2.0 

func Log1p ¶

func Log1p(x float64) float64

Log1p returns the natural logarithm of 1 plus its argument x. It is more accurate than Log(1 + x) when x is near zero.

Special cases are:

Log1p(+Inf) = +Inf Log1p(±0) = ±0 Log1p(-1) = -Inf Log1p(x < -1) = NaN Log1p(NaN) = NaN 

func Log2 ¶

func Log2(x float64) float64

Log2 returns the binary logarithm of x. The special cases are the same as for Log.

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.1f", math.Log2(256)) } 

Output: 8.0 

func Logb ¶

func Logb(x float64) float64

Logb returns the binary exponent of x.

Special cases are:

Logb(±Inf) = +Inf Logb(0) = -Inf Logb(NaN) = NaN 

func Max ¶

func Max(x, y float64) float64

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 

Note that this differs from the built-in function max when called with NaN and +Inf.

func Min ¶

func Min(x, y float64) float64

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 

Note that this differs from the built-in function min when called with NaN and -Inf.

func Mod ¶

func Mod(x, y float64) float64

Mod returns the floating-point remainder of x/y. The magnitude of the result is less than y and its sign agrees with that of x.

Special cases are:

Mod(±Inf, y) = NaN Mod(NaN, y) = NaN Mod(x, 0) = NaN Mod(x, ±Inf) = x Mod(x, NaN) = NaN 

 package main import (	"fmt"	"math" ) func main() {	c := math.Mod(7, 4)	fmt.Printf("%.1f", c) } 

Output: 3.0 

func Modf ¶

func Modf(f float64) (int float64, frac float64)

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 

 package main import (	"fmt"	"math" ) func main() {	int, frac := math.Modf(3.14)	fmt.Printf("%.2f, %.2f\n", int, frac)	int, frac = math.Modf(-2.71)	fmt.Printf("%.2f, %.2f\n", int, frac) } 

Output: 3.00, 0.14 -2.00, -0.71 

func NaN ¶

func NaN() float64

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

func Nextafter ¶

func Nextafter(x, y float64) (r float64)

Nextafter returns the next representable float64 value after x towards y.

Special cases are:

Nextafter(x, x) = x Nextafter(NaN, y) = NaN Nextafter(x, NaN) = NaN 

func Nextafter32 ¶ added in go1.4

func Nextafter32(x, y float32) (r float32)

Nextafter32 returns the next representable float32 value after x towards y.

Special cases are:

Nextafter32(x, x) = x Nextafter32(NaN, y) = NaN Nextafter32(x, NaN) = NaN 

func Pow ¶

func Pow(x, y float64) float64

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 

 package main import (	"fmt"	"math" ) func main() {	c := math.Pow(2, 3)	fmt.Printf("%.1f", c) } 

Output: 8.0 

func Pow10 ¶

func Pow10(n int) float64

Pow10 returns 10**n, the base-10 exponential of n.

Special cases are:

Pow10(n) = 0 for n < -323 Pow10(n) = +Inf for n > 308 

 package main import (	"fmt"	"math" ) func main() {	c := math.Pow10(2)	fmt.Printf("%.1f", c) } 

Output: 100.0 

func Remainder ¶

func Remainder(x, y float64) float64

Remainder returns the IEEE 754 floating-point remainder of x/y.

Special cases are:

Remainder(±Inf, y) = NaN Remainder(NaN, y) = NaN Remainder(x, 0) = NaN Remainder(x, ±Inf) = x Remainder(x, NaN) = NaN 

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.1f", math.Remainder(100, 30)) } 

Output: 10.0 

func Round ¶ added in go1.10

func Round(x float64) float64

Round returns the nearest integer, rounding half away from zero.

Special cases are:

Round(±0) = ±0 Round(±Inf) = ±Inf Round(NaN) = NaN 

 package main import (	"fmt"	"math" ) func main() {	p := math.Round(10.5)	fmt.Printf("%.1f\n", p)	n := math.Round(-10.5)	fmt.Printf("%.1f\n", n) } 

Output: 11.0 -11.0 

func RoundToEven ¶ added in go1.10

func RoundToEven(x float64) float64

RoundToEven returns the nearest integer, rounding ties to even.

Special cases are:

RoundToEven(±0) = ±0 RoundToEven(±Inf) = ±Inf RoundToEven(NaN) = NaN 

 package main import (	"fmt"	"math" ) func main() {	u := math.RoundToEven(11.5)	fmt.Printf("%.1f\n", u)	d := math.RoundToEven(12.5)	fmt.Printf("%.1f\n", d) } 

Output: 12.0 12.0 

func Signbit ¶

func Signbit(x float64) bool

Signbit reports whether x is negative or negative zero.

func Sin ¶

func Sin(x float64) float64

Sin returns the sine of the radian argument x.

Special cases are:

Sin(±0) = ±0 Sin(±Inf) = NaN Sin(NaN) = NaN 

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.2f", math.Sin(math.Pi)) } 

Output: 0.00 

func Sincos ¶

func Sincos(x float64) (sin, cos float64)

Sincos returns Sin(x), Cos(x).

Special cases are:

Sincos(±0) = ±0, 1 Sincos(±Inf) = NaN, NaN Sincos(NaN) = NaN, NaN 

 package main import (	"fmt"	"math" ) func main() {	sin, cos := math.Sincos(0)	fmt.Printf("%.2f, %.2f", sin, cos) } 

Output: 0.00, 1.00 

func Sinh ¶

func Sinh(x float64) float64

Sinh returns the hyperbolic sine of x.

Special cases are:

Sinh(±0) = ±0 Sinh(±Inf) = ±Inf Sinh(NaN) = NaN 

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.2f", math.Sinh(0)) } 

Output: 0.00 

func Sqrt ¶

func Sqrt(x float64) float64

Sqrt returns the square root of x.

Special cases are:

Sqrt(+Inf) = +Inf Sqrt(±0) = ±0 Sqrt(x < 0) = NaN Sqrt(NaN) = NaN 

 package main import (	"fmt"	"math" ) func main() {	const (	a = 3	b = 4	)	c := math.Sqrt(a*a + b*b)	fmt.Printf("%.1f", c) } 

Output: 5.0 

func Tan ¶

func Tan(x float64) float64

Tan returns the tangent of the radian argument x.

Special cases are:

Tan(±0) = ±0 Tan(±Inf) = NaN Tan(NaN) = NaN 

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.2f", math.Tan(0)) } 

Output: 0.00 

func Tanh ¶

func Tanh(x float64) float64

Tanh returns the hyperbolic tangent of x.

Special cases are:

Tanh(±0) = ±0 Tanh(±Inf) = ±1 Tanh(NaN) = NaN 

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.2f", math.Tanh(0)) } 

Output: 0.00 

func Trunc ¶

func Trunc(x float64) float64

Trunc returns the integer value of x.

Special cases are:

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

 package main import (	"fmt"	"math" ) func main() {	fmt.Printf("%.2f\n", math.Trunc(math.Pi))	fmt.Printf("%.2f\n", math.Trunc(-1.2345)) } 

Output: 3.00 -1.00 

func Y0 ¶

func Y0(x float64) float64

Y0 returns the order-zero Bessel function of the second kind.

Special cases are:

Y0(+Inf) = 0 Y0(0) = -Inf Y0(x < 0) = NaN Y0(NaN) = NaN 

func Y1 ¶

func Y1(x float64) float64

Y1 returns the order-one Bessel function of the second kind.

Special cases are:

Y1(+Inf) = 0 Y1(0) = -Inf Y1(x < 0) = NaN Y1(NaN) = NaN 

func Yn ¶

func Yn(n int, x float64) float64

Yn returns the order-n Bessel function of the second kind.

Special cases are:

Yn(n, +Inf) = 0 Yn(n ≥ 0, 0) = -Inf Yn(n < 0, 0) = +Inf if n is odd, -Inf if n is even Yn(n, x < 0) = NaN Yn(n, NaN) = NaN