mirror of
https://github.com/gonum/gonum.git
synced 2025-10-31 10:36:30 +08:00
67 lines
1.4 KiB
Go
67 lines
1.4 KiB
Go
// Copyright ©2013 The Gonum Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package unit
|
|
|
|
import (
|
|
"errors"
|
|
"fmt"
|
|
"math"
|
|
)
|
|
|
|
// Dimless represents a dimensionless constant
|
|
type Dimless float64
|
|
|
|
const (
|
|
One Dimless = 1.0
|
|
)
|
|
|
|
// Unit converts the Dimless to a unit
|
|
func (d Dimless) Unit() *Unit {
|
|
return New(float64(d), Dimensions{})
|
|
}
|
|
|
|
// Dimless allows Dimless to implement a Dimlesser interface
|
|
func (d Dimless) Dimless() Dimless {
|
|
return d
|
|
}
|
|
|
|
// From converts the unit to a dimless. Returns an error if there
|
|
// is a mismatch in dimension
|
|
func (d *Dimless) From(u *Unit) error {
|
|
if !DimensionsMatch(u, One) {
|
|
(*d) = Dimless(math.NaN())
|
|
return errors.New("Dimension mismatch")
|
|
}
|
|
(*d) = Dimless(u.Unit().Value())
|
|
return nil
|
|
}
|
|
|
|
func (d Dimless) Format(fs fmt.State, c rune) {
|
|
switch c {
|
|
case 'v':
|
|
if fs.Flag('#') {
|
|
fmt.Fprintf(fs, "%T(%v)", d, float64(d))
|
|
return
|
|
}
|
|
fallthrough
|
|
case 'e', 'E', 'f', 'F', 'g', 'G':
|
|
p, pOk := fs.Precision()
|
|
w, wOk := fs.Width()
|
|
switch {
|
|
case pOk && wOk:
|
|
fmt.Fprintf(fs, "%*.*"+string(c), w, p, float64(d))
|
|
case pOk:
|
|
fmt.Fprintf(fs, "%.*"+string(c), p, float64(d))
|
|
case wOk:
|
|
fmt.Fprintf(fs, "%*"+string(c), w, float64(d))
|
|
default:
|
|
fmt.Fprintf(fs, "%"+string(c), float64(d))
|
|
}
|
|
default:
|
|
fmt.Fprintf(fs, "%%!%c(%T=%g)", c, d, float64(d))
|
|
return
|
|
}
|
|
}
|