util

Documentation

Overview

Package util provides miscellaneous maths functions.

Index

• func Assert(test bool)
• func Check(err error)
• func CheckNaN(v float64)
• func CheckNaNVec(v [3]float64)
• func Cos(x float64) float64
• func Dither(rng *rand.Rand, x float64) int
• func Frac(x float64) float64
• func IsBad(v float64) bool
• func IsBadVec(v [3]float64) bool
• func Max(x, y float64) float64
• func Max3(x, y, z float64) float64
• func Min(x, y float64) float64
• func Re(x float64) float64
• func Sin(x float64) float64
• func Sinc(x float64) float64
• func Sqr(x float64) float64

Examples

• Frac

Functions

func Assert

func Assert(test bool)

func Check

func Check(err error)

func CheckNaN

func CheckNaN(v float64)

func CheckNaNVec

func CheckNaNVec(v [3]float64)

func Cos

func Cos(x float64) float64

Cos is like math.Cos, but returns exactly 0 for arguments Pi/2, -Pi/2. this avoids annoying round-off errors for rotations of multiples of 90 degrees.

func Dither

func Dither(rng *rand.Rand, x float64) int

func Frac

func Frac(x float64) float64

Frac returns x % 1, using python-like modulus.

Example

for _, x := range []float64{-2.1, -2, -1.9, -1, -0.1, 0, 0.1, 0.9, 1, 1.1, 2, 2.1} {
	fmt.Printf("Frac(% .1f) = % .1f\n", x, Frac(x))
}

Output:

Frac(-2.1) =  0.9
Frac(-2.0) =  0.0
Frac(-1.9) =  0.1
Frac(-1.0) =  0.0
Frac(-0.1) =  0.9
Frac( 0.0) =  0.0
Frac( 0.1) =  0.1
Frac( 0.9) =  0.9
Frac( 1.0) =  0.0
Frac( 1.1) =  0.1
Frac( 2.0) =  0.0
Frac( 2.1) =  0.1

func IsBad

func IsBad(v float64) bool

func IsBadVec

func IsBadVec(v [3]float64) bool

func Max

func Max(x, y float64) float64

func Max3

func Max3(x, y, z float64) float64

func Min

func Min(x, y float64) float64

func Re

func Re(x float64) float64

func Sin

func Sin(x float64) float64

Sin is like math.Sin, but returns exactly 0 for arguments Pi, -Pi. this avoids annoying round-off errors for rotations of multiples of 90 degrees.

func Sinc

func Sinc(x float64) float64

Sinc returns sin(x)/x, handling x == 0 gracefully.

func Sqr

func Sqr(x float64) float64