go-chart/util.go
Will Charczuk d888440415 tests.
2016-07-15 09:17:51 -07:00

164 lines
3.3 KiB
Go

package chart
import (
"fmt"
"math"
"math/rand"
"time"
)
// Float is an alias for float64 that provides a better .String() method.
type Float float64
// String returns the string representation of a float.
func (f Float) String() string {
return fmt.Sprintf("%.2f", f)
}
// TimeToFloat64 returns a float64 representation of a time.
func TimeToFloat64(t time.Time) float64 {
return float64(t.Unix())
}
// MinAndMax returns both the min and max in one pass.
func MinAndMax(values ...float64) (min float64, max float64) {
if len(values) == 0 {
return
}
min = values[0]
max = values[0]
for _, v := range values {
if max < v {
max = v
}
if min > v {
min = v
}
}
return
}
// MinAndMaxOfTime returns the min and max of a given set of times
// in one pass.
func MinAndMaxOfTime(values ...time.Time) (min time.Time, max time.Time) {
if len(values) == 0 {
return
}
min = values[0]
max = values[0]
for _, v := range values {
if max.Before(v) {
max = v
}
if min.After(v) {
min = v
}
}
return
}
// Slices generates N slices that span the total.
// The resulting array will be intermediate indexes until total.
func Slices(count int, total float64) []float64 {
var values []float64
sliceWidth := float64(total) / float64(count)
for cursor := 0.0; cursor < total; cursor += sliceWidth {
values = append(values, cursor)
}
return values
}
// GetRoundToForDelta returns a `roundTo` value for a given delta.
func GetRoundToForDelta(delta float64) float64 {
startingDeltaBound := math.Pow(10.0, 10.0)
for cursor := startingDeltaBound; cursor > 0; cursor /= 10.0 {
if delta > cursor {
return cursor / 10.0
}
}
return 0.0
}
// RoundUp rounds up to a given roundTo value.
func RoundUp(value, roundTo float64) float64 {
d1 := math.Ceil(value / roundTo)
return d1 * roundTo
}
// RoundDown rounds down to a given roundTo value.
func RoundDown(value, roundTo float64) float64 {
d1 := math.Floor(value / roundTo)
return d1 * roundTo
}
// MinInt returns the minimum of a set of integers.
func MinInt(values ...int) int {
min := math.MaxInt32
for _, v := range values {
if v < min {
min = v
}
}
return min
}
// MaxInt returns the maximum of a set of integers.
func MaxInt(values ...int) int {
max := math.MinInt32
for _, v := range values {
if v > max {
max = v
}
}
return max
}
// AbsInt returns the absolute value of an integer.
func AbsInt(value int) int {
if value < 0 {
return -value
}
return value
}
// Seq produces an array of floats from [start,end] by optional steps.
func Seq(start, end float64, steps ...float64) []float64 {
var values []float64
step := 1.0
if len(steps) > 0 {
step = steps[0]
}
if start < end {
for x := start; x <= end; x += step {
values = append(values, x)
}
} else {
for x := start; x >= end; x = x - step {
values = append(values, x)
}
}
return values
}
// SeqRand generates a random sequence.
func SeqRand(samples int, scale float64) []float64 {
rnd := rand.New(rand.NewSource(time.Now().Unix()))
values := make([]float64, samples)
for x := 0; x < samples; x++ {
values[x] = rnd.Float64() * scale
}
return values
}
// PercentDifference computes the percentage difference between two values.
// The formula is (v2-v1)/v1.
func PercentDifference(v1, v2 float64) float64 {
return (v2 - v1) / v1
}