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compute convergents with channels

This commit is contained in:
filifa 2025-09-05 20:35:10 -04:00
parent e8ae7e3e3e
commit 0f98a371e8
2 changed files with 34 additions and 37 deletions
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52
cmd/convergents.go
View File

@ -23,45 +23,49 @@ import (
"github.com/spf13/cobra"
)
func gaussianBrackets(x, xprev, a *big.Int) {
tmp := new(big.Int)
tmp.Mul(a, x)
tmp.Add(tmp, xprev)
xprev.Set(x)
x.Set(tmp)
func cycle(seq []*big.Int, ch chan *big.Int) {
n := len(seq)
for i := 0; true; i = (i + 1) % n {
ch <- seq[i]
}
}
func gaussianBrackets(x, xprev *big.Int, seq []*big.Int, ch chan *big.Int) {
c := make(chan *big.Int)
go cycle(seq, c)
for a := range c {
tmp := new(big.Int)
tmp.Mul(a, x)
tmp.Add(tmp, xprev)
xprev.Set(x)
x.Set(tmp)
ch <- tmp
}
}
func convergents(cmd *cobra.Command, args []string) {
hprev := big.NewInt(0)
kprev := big.NewInt(1)
h := big.NewInt(1)
k := big.NewInt(0)
a0, ok := new(big.Int).SetString(args[0], 10)
if !ok {
cobra.CheckErr("invalid input " + args[0])
}
denoms := make([]big.Int, len(args[1:]))
denoms := make([]*big.Int, len(args[1:]))
for i, d := range args[1:] {
_, ok = denoms[i].SetString(d, 10)
denoms[i] = new(big.Int)
_, ok := denoms[i].SetString(d, 10)
if !ok {
cobra.CheckErr("invalid input " + d)
}
}
gaussianBrackets(h, hprev, a0)
gaussianBrackets(k, kprev, a0)
r := new(big.Rat).SetFrac(h, k)
fmt.Println(r)
for i := 0; true; i = (i + 1) % len(denoms) {
a := &denoms[i]
gaussianBrackets(h, hprev, a)
gaussianBrackets(k, kprev, a)
hch := make(chan *big.Int)
kch := make(chan *big.Int)
go gaussianBrackets(a0, big.NewInt(1), denoms, hch)
go gaussianBrackets(big.NewInt(1), big.NewInt(0), denoms, kch)
r := new(big.Rat)
for {
h, k := <-hch, <-kch
r.SetFrac(h, k)
fmt.Println(r)
}

19
cmd/pell.go
View File

@ -39,16 +39,13 @@ func pell(cmd *cobra.Command, args []string) {
cobra.CheckErr(pellCoeff + " is a perfect square")
}
hprev := big.NewInt(0)
kprev := big.NewInt(1)
hch := make(chan *big.Int)
kch := make(chan *big.Int)
go gaussianBrackets(a0, big.NewInt(1), repetend, hch)
go gaussianBrackets(big.NewInt(1), big.NewInt(0), repetend, kch)
h := big.NewInt(1)
k := big.NewInt(0)
gaussianBrackets(h, hprev, a0)
gaussianBrackets(k, kprev, a0)
for i := 0; true; i = (i + 1) % len(repetend) {
for {
h, k := <-hch, <-kch
foo := new(big.Int).Exp(k, big.NewInt(2), nil)
foo.Mul(d, foo)
@ -58,10 +55,6 @@ func pell(cmd *cobra.Command, args []string) {
if bar.Cmp(big.NewInt(1)) == 0 {
fmt.Println(h, k)
}
a := repetend[i]
gaussianBrackets(h, hprev, a)
gaussianBrackets(k, kprev, a)
}
}