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gonum/unit/constant/generate_constants.go
Dan Kortschak ccc0da248a all: run make builds pass with go master
Run gofmt go1.17 adds the new //go:build comments
2021-04-19 15:00:56 +09:30

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// Copyright ©2014 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.
//go:build ignore
// +build ignore
package main
import (
"bytes"
"go/format"
"log"
"math"
"os"
"strings"
"text/template"
"gonum.org/v1/gonum/unit"
)
const (
elementaryCharge = 1.602176634e-19
fineStructure = 7.2973525693e-3
lightSpeed = 2.99792458e8
planck = 6.62607015e-34
)
var constants = []Constant{
{
Name: "AtomicMass", Value: 1.66053906660e-27,
Dimensions: []Dimension{{massName, 1}},
Comment: "AtomicMass is the atomic mass constant (mᵤ), one twelfth of the mass of an unbound atom of carbon-12 at rest and in its ground state.",
Uncertainty: 0.00000000050e-27,
},
{
Name: "Avogadro", Value: 6.02214076e23,
Dimensions: []Dimension{{moleName, -1}},
Comment: "Avogadro is the Avogadro constant (A), the number of constituent particles contained in one mole of a substance.",
},
{
Name: "Boltzmann", Value: 1.380649e-23,
Dimensions: []Dimension{{massName, 1}, {lengthName, 2}, {timeName, -2}, {temperatureName, -1}},
Comment: "Boltzmann is the Boltzmann constant (k), it relates the average relative kinetic energy of particles in a gas with the temperature of the gas.",
},
{
Name: "ElectricConstant", Value: 1 / (4 * math.Pi * 1e-7 * lightSpeed * lightSpeed),
Dimensions: []Dimension{{currentName, 2}, {timeName, 4}, {massName, -1}, {lengthName, -3}},
Comment: "ElectricConstant is the electric constant (ε₀), the value of the absolute dielectric permittivity of classical vacuum.",
Uncertainty: 0.0000000013e-12,
},
{
Name: "ElementaryCharge", Value: elementaryCharge,
Dimensions: []Dimension{{currentName, 1}, {timeName, 1}},
Comment: "ElementaryCharge, is the elementary charge constant (e), the magnitude of electric charge carried by a single proton or electron.",
},
{
Name: "Faraday", Value: 96485.33212,
Dimensions: []Dimension{{currentName, 1}, {timeName, 1}, {moleName, -1}},
Comment: "Faraday is the Faraday constant, the magnitude of electric charge per mole of electrons.",
},
{
Name: "FineStructure", Value: fineStructure,
Comment: "FineStructure is the fine structure constant (α), it describes the strength of the electromagnetic interaction between elementary charged particles.",
Uncertainty: 0.0000000011e-3,
},
{
Name: "Gravitational", Value: 6.67430e-11,
Dimensions: []Dimension{{massName, -1}, {lengthName, 3}, {timeName, -2}},
Comment: "Gravitational is the universal gravitational constant (G), the proportionality constant connecting the gravitational force between two bodies.",
Uncertainty: 0.00015e-11,
},
{
Name: "LightSpeedInVacuum", Value: lightSpeed,
Dimensions: []Dimension{{lengthName, 1}, {timeName, -1}},
Comment: "LightSpeedInVacuum is the c constant, the speed of light in a vacuum.",
},
{
Name: "MagneticConstant", Value: 2 * fineStructure * planck / (elementaryCharge * elementaryCharge * lightSpeed),
Dimensions: []Dimension{{currentName, 2}, {timeName, 4}, {massName, -1}, {lengthName, -3}},
Comment: "MagneticConstant is the magnetic constant (μ₀), the magnetic permeability in a classical vacuum.",
Uncertainty: 0.00000000019e-6,
},
{
Name: "Planck", Value: planck,
Dimensions: []Dimension{{massName, 1}, {lengthName, 2}, {timeName, -1}},
Comment: "Planck is the Planck constant (h), it relates the energy carried by a photon to its frequency.",
},
{
Name: "StandardGravity", Value: 9.80665,
Dimensions: []Dimension{{lengthName, 1}, {timeName, -2}},
Comment: "StandardGravity is the standard gravity constant (g₀), the nominal gravitational acceleration of an object in a vacuum near the surface of the Earth",
},
}
const (
angleName = "AngleDim"
currentName = "CurrentDim"
lengthName = "LengthDim"
luminousIntensityName = "LuminousIntensityDim"
massName = "MassDim"
moleName = "MoleDim"
temperatureName = "TemperatureDim"
timeName = "TimeDim"
)
var dimOf = map[string]unit.Dimension{
"AngleDim": unit.AngleDim,
"CurrentDim": unit.CurrentDim,
"LengthDim": unit.LengthDim,
"LuminousIntensityDim": unit.LuminousIntensityDim,
"MassDim": unit.MassDim,
"MoleDim": unit.MoleDim,
"TemperatureDim": unit.TemperatureDim,
"TimeDim": unit.TimeDim,
}
type Constant struct {
Name string
Value float64
Dimensions []Dimension
Comment string
Uncertainty float64
}
type Dimension struct {
Name string
Power int
}
func (c Constant) IsDefined() bool {
return definedEquivalentOf(unit.New(1, c.dimensions())) != ""
}
func (c Constant) Type() string {
typ := definedEquivalentOf(unit.New(1, c.dimensions()))
if typ == "" {
return strings.ToLower(c.Name[:1]) + c.Name[1:] + "Units"
}
return typ
}
func (c Constant) Units() string {
return c.dimensions().String()
}
func (c Constant) dimensions() unit.Dimensions {
dims := make(unit.Dimensions)
for _, d := range c.Dimensions {
dims[dimOf[d.Name]] = d.Power
}
return dims
}
// Generate a file for each of the constants.
func main() {
for _, c := range constants {
generate(c)
generateTest(c)
}
}
const baseUnitTemplate = `// Code generated by "go generate gonum.org/v1/gonum/unit/constant”; DO NOT EDIT.
// Copyright ©2019 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 constant
import "gonum.org/v1/gonum/unit"
// {{.Comment}}{{if .Dimensions}}
// {{$n := len .Dimensions}}The dimension{{if gt $n 1}}s{{end}} of {{.Name}} {{if eq $n 1}}is{{else}}are{{end}} {{.Units}}.{{end}} {{if not .Uncertainty}}The constant is exact.{{else}}The standard uncertainty of the constant is {{.Uncertainty}} {{.Units}}.{{end}}
const {{.Name}} = {{.Type}}({{.Value}})
`
var baseUnit = template.Must(template.New("base").Parse(baseUnitTemplate))
const methodTemplate = `// Code generated by "go generate gonum.org/v1/gonum/unit/constant”; DO NOT EDIT.
// Copyright ©2019 The Gonum Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package constant
import (
"fmt"
"gonum.org/v1/gonum/unit"
)
// {{.Comment}}
// {{$n := len .Dimensions}}The dimension{{if gt $n 1}}s{{end}} of {{.Name}} {{if eq $n 1}}is{{else}}are{{end}} {{.Units}}. {{if not .Uncertainty}}The constant is exact.{{else}}The standard uncertainty of the constant is {{.Uncertainty}} {{.Units}}.{{end}}
const {{.Name}} = {{.Type}}({{.Value}})
type {{.Type}} float64
// Unit converts the {{.Type}} to a *unit.Unit
func (cnst {{.Type}}) Unit() *unit.Unit {
return unit.New(float64(cnst), unit.Dimensions{
{{range .Dimensions}} unit.{{.Name}}: {{.Power}},
{{end}}
})
}
func (cnst {{.Type}}) Format(fs fmt.State, c rune) {
switch c {
case 'v':
if fs.Flag('#') {
fmt.Fprintf(fs, "%T(%v)", cnst, float64(cnst))
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, cnst.Unit())
case pOk:
fmt.Fprintf(fs, "%.*"+string(c), p, cnst.Unit())
case wOk:
fmt.Fprintf(fs, "%*"+string(c), w, cnst.Unit())
default:
fmt.Fprintf(fs, "%"+string(c), cnst.Unit())
}
default:
fmt.Fprintf(fs, "%%!"+string(c)+"(constant.{{.Type}}=%v {{.Units}})", float64(cnst))
}
}
`
var methods = template.Must(template.New("methods").Parse(methodTemplate))
func generate(c Constant) {
lowerName := strings.ToLower(c.Name)
filename := lowerName + ".go"
f, err := os.Create(filename)
if err != nil {
log.Fatal(err)
}
defer f.Close()
var buf bytes.Buffer
if c.IsDefined() {
err = baseUnit.Execute(&buf, c)
if err != nil {
log.Fatal(err)
}
} else {
err = methods.Execute(&buf, c)
if err != nil {
log.Fatal(err)
}
}
b, err := format.Source(buf.Bytes())
if err != nil {
f.Write(buf.Bytes()) // This is here to debug bad format.
log.Fatalf("error formatting %q: %s", c.Name, err)
}
f.Write(b)
}
const testTemplate = `// Code generated by "go generate gonum.org/v1/gonum/unit/constant”; DO NOT EDIT.
// Copyright ©2019 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 constant
import (
"fmt"
"testing"
)
func Test{{.Name}}Format(t *testing.T) {
t.Parallel()
for _, test := range []struct{
format string
want string
}{
{"%v", "{{.Value}} {{.Units}}"},
{"%.1v", "{{printf "%.1v" .Value}} {{.Units}}"},
{"%50.1v", "{{$s := printf "%.1v %s" .Value .Units}}{{printf "%50s" $s}}"},
{"%50v", "{{$s := printf "%v %s" .Value .Units}}{{printf "%50s" $s}}"},
{"%1v", "{{.Value}} {{.Units}}"},
{"%#v", "constant.{{.Type}}({{.Value}})"},
{"%s", "%!s(constant.{{.Type}}={{.Value}} {{.Units}})"},
} {
got := fmt.Sprintf(test.format, {{.Name}})
if got != test.want {
t.Errorf("Format %q: got: %q want: %q", test.format, got, test.want)
}
}
}
`
var tests = template.Must(template.New("test").Parse(testTemplate))
func generateTest(c Constant) {
if c.IsDefined() {
return
}
lowerName := strings.ToLower(c.Name)
filename := lowerName + "_test.go"
f, err := os.Create(filename)
if err != nil {
log.Fatal(err)
}
defer f.Close()
var buf bytes.Buffer
err = tests.Execute(&buf, c)
if err != nil {
log.Fatal(err)
}
b, err := format.Source(buf.Bytes())
if err != nil {
f.Write(buf.Bytes()) // This is here to debug bad format.
log.Fatalf("error formatting test for %q: %s", c.Name, err)
}
f.Write(b)
}