mirror of
https://github.com/golang/go
synced 2024-11-23 22:50:05 -07:00
e24977d231
The next CL will remove the -G flag, effectively hard-coding it to its current default (-G=3). Change-Id: Ib4743b529206928f9f1cca9fdb19989728327831 Reviewed-on: https://go-review.googlesource.com/c/go/+/388534 Reviewed-by: Keith Randall <khr@golang.org> Trust: Matthew Dempsky <mdempsky@google.com> Run-TryBot: Matthew Dempsky <mdempsky@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
99 lines
2.6 KiB
Go
99 lines
2.6 KiB
Go
// run
|
|
|
|
// Copyright 2022 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
// absdiff example using a function argument rather than attaching an
|
|
// Abs method to a structure containing base types.
|
|
|
|
package main
|
|
|
|
import (
|
|
"fmt"
|
|
"math"
|
|
)
|
|
|
|
type Numeric interface {
|
|
OrderedNumeric | Complex
|
|
}
|
|
|
|
// absDifference computes the absolute value of the difference of
|
|
// a and b, where the absolute value is determined by the abs function.
|
|
func absDifference[T Numeric](a, b T, abs func(a T) T) T {
|
|
return abs(a - b)
|
|
}
|
|
|
|
// OrderedNumeric matches numeric types that support the < operator.
|
|
type OrderedNumeric interface {
|
|
~int | ~int8 | ~int16 | ~int32 | ~int64 |
|
|
~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr |
|
|
~float32 | ~float64
|
|
}
|
|
|
|
func Abs[T OrderedNumeric](a T) T {
|
|
if a < 0 {
|
|
return -a
|
|
}
|
|
return a
|
|
}
|
|
|
|
// Complex matches the two complex types, which do not have a < operator.
|
|
type Complex interface {
|
|
~complex64 | ~complex128
|
|
}
|
|
|
|
func realimag(x any) (re, im float64) {
|
|
switch z := x.(type) {
|
|
case complex64:
|
|
re = float64(real(z))
|
|
im = float64(imag(z))
|
|
case complex128:
|
|
re = real(z)
|
|
im = imag(z)
|
|
default:
|
|
panic("unknown complex type")
|
|
}
|
|
return
|
|
}
|
|
|
|
func ComplexAbs[T Complex](a T) T {
|
|
// TODO use direct conversion instead of realimag once #50937 is fixed
|
|
r, i := realimag(a)
|
|
// r := float64(real(a))
|
|
// i := float64(imag(a))
|
|
d := math.Sqrt(r*r + i*i)
|
|
return T(complex(d, 0))
|
|
}
|
|
|
|
// OrderedAbsDifference returns the absolute value of the difference
|
|
// between a and b, where a and b are of an ordered type.
|
|
func OrderedAbsDifference[T OrderedNumeric](a, b T) T {
|
|
return absDifference(a, b, Abs[T])
|
|
}
|
|
|
|
// ComplexAbsDifference returns the absolute value of the difference
|
|
// between a and b, where a and b are of a complex type.
|
|
func ComplexAbsDifference[T Complex](a, b T) T {
|
|
return absDifference(a, b, ComplexAbs[T])
|
|
}
|
|
|
|
func main() {
|
|
if got, want := OrderedAbsDifference(1.0, -2.0), 3.0; got != want {
|
|
panic(fmt.Sprintf("got = %v, want = %v", got, want))
|
|
}
|
|
if got, want := OrderedAbsDifference(-1.0, 2.0), 3.0; got != want {
|
|
panic(fmt.Sprintf("got = %v, want = %v", got, want))
|
|
}
|
|
if got, want := OrderedAbsDifference(-20, 15), 35; got != want {
|
|
panic(fmt.Sprintf("got = %v, want = %v", got, want))
|
|
}
|
|
|
|
if got, want := ComplexAbsDifference(5.0+2.0i, 2.0-2.0i), 5+0i; got != want {
|
|
panic(fmt.Sprintf("got = %v, want = %v", got, want))
|
|
}
|
|
if got, want := ComplexAbsDifference(2.0-2.0i, 5.0+2.0i), 5+0i; got != want {
|
|
panic(fmt.Sprintf("got = %v, want = %v", got, want))
|
|
}
|
|
}
|