RosettaCodeData/Task/Imaginary-base-numbers/Go/imaginary-base-numbers.go

148 lines
3.4 KiB
Go

package main
import (
"fmt"
"math"
"strconv"
"strings"
)
const (
twoI = 2.0i
invTwoI = 1.0 / twoI
)
type quaterImaginary struct {
b2i string
}
func reverse(s string) string {
r := []rune(s)
for i, j := 0, len(r)-1; i < len(r)/2; i, j = i+1, j-1 {
r[i], r[j] = r[j], r[i]
}
return string(r)
}
func newQuaterImaginary(b2i string) quaterImaginary {
b2i = strings.TrimSpace(b2i)
_, err := strconv.ParseFloat(b2i, 64)
if err != nil {
panic("invalid Base 2i number")
}
return quaterImaginary{b2i}
}
func toComplex(q quaterImaginary) complex128 {
pointPos := strings.Index(q.b2i, ".")
var posLen int
if pointPos != -1 {
posLen = pointPos
} else {
posLen = len(q.b2i)
}
sum := 0.0i
prod := complex(1.0, 0.0)
for j := 0; j < posLen; j++ {
k := float64(q.b2i[posLen-1-j] - '0')
if k > 0.0 {
sum += prod * complex(k, 0.0)
}
prod *= twoI
}
if pointPos != -1 {
prod = invTwoI
for j := posLen + 1; j < len(q.b2i); j++ {
k := float64(q.b2i[j] - '0')
if k > 0.0 {
sum += prod * complex(k, 0.0)
}
prod *= invTwoI
}
}
return sum
}
func (q quaterImaginary) String() string {
return q.b2i
}
// only works properly if 'real' and 'imag' are both integral
func toQuaterImaginary(c complex128) quaterImaginary {
if c == 0i {
return quaterImaginary{"0"}
}
re := int(real(c))
im := int(imag(c))
fi := -1
var sb strings.Builder
for re != 0 {
rem := re % -4
re /= -4
if rem < 0 {
rem += 4
re++
}
sb.WriteString(strconv.Itoa(rem))
sb.WriteString("0")
}
if im != 0 {
f := real(complex(0.0, imag(c)) / 2.0i)
im = int(math.Ceil(f))
f = -4.0 * (f - float64(im))
index := 1
for im != 0 {
rem := im % -4
im /= -4
if rem < 0 {
rem += 4
im++
}
if index < sb.Len() {
bs := []byte(sb.String())
bs[index] = byte(rem + 48)
sb.Reset()
sb.Write(bs)
} else {
sb.WriteString("0")
sb.WriteString(strconv.Itoa(rem))
}
index += 2
}
fi = int(f)
}
s := reverse(sb.String())
if fi != -1 {
s = fmt.Sprintf("%s.%d", s, fi)
}
s = strings.TrimLeft(s, "0")
if s[0] == '.' {
s = "0" + s
}
return newQuaterImaginary(s)
}
func main() {
for i := 1; i <= 16; i++ {
c1 := complex(float64(i), 0.0)
qi := toQuaterImaginary(c1)
c2 := toComplex(qi)
fmt.Printf("%4.0f -> %8s -> %4.0f ", real(c1), qi, real(c2))
c1 = -c1
qi = toQuaterImaginary(c1)
c2 = toComplex(qi)
fmt.Printf("%4.0f -> %8s -> %4.0f\n", real(c1), qi, real(c2))
}
fmt.Println()
for i := 1; i <= 16; i++ {
c1 := complex(0.0, float64(i))
qi := toQuaterImaginary(c1)
c2 := toComplex(qi)
fmt.Printf("%3.0fi -> %8s -> %3.0fi ", imag(c1), qi, imag(c2))
c1 = -c1
qi = toQuaterImaginary(c1)
c2 = toComplex(qi)
fmt.Printf("%3.0fi -> %8s -> %3.0fi\n", imag(c1), qi, imag(c2))
}
}