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|
package main
import (
"bufio"
"flag"
"fmt"
"io"
"os"
"sort"
"strconv"
"strings"
"sync"
"time"
"github.com/fxtlabs/primes"
"github.com/pkg/profile"
"golang.org/x/text/language"
"golang.org/x/text/message"
)
func main() {
n := flag.Int("n", 100_000, "n")
k := flag.Int("k", 5, "k")
path := flag.String("path", "-", "path")
prof := flag.Bool("prof", true, "profile")
dbg := flag.Bool("debug", false, "debug")
vrb := flag.Bool("verbose", true, "verbose")
mt := flag.Bool("mt", false, "parallel")
cache := flag.Int("cache", -1, "cache")
flag.Parse()
debug = *dbg
verbose = *vrb
var dst io.Writer = os.Stdout
if p := strings.TrimSpace(*path); p != "-" && p != "" {
f, err := os.Create(p)
if err != nil {
panic(err)
}
dst = f
defer f.Close()
}
if *cache > -1 {
primes_cache = load_primes(*cache)
} else {
k := 1
for i := len(strconv.Itoa(*n/10)) * 2; i > 0; i-- {
k *= 10
}
primes_cache = load_primes(k)
}
st := time.Now()
defer func() {
fmt.Fprintln(os.Stderr, time.Since(st))
}()
if *prof {
defer profile.Start(profile.CPUProfile, profile.ProfilePath(".")).Stop()
}
out := dst
fn := combin_primes
if *mt {
fn = combin_primes_mt
}
print_res := func(res []int) {
fmt.Fprint(out, " => ")
s := 0
for _, r := range res[:len(res)-1] {
fmt.Fprintf(out, "%v,", r)
s += r
}
fmt.Fprintf(out, "%v", res[len(res)-1])
s += res[len(res)-1]
fmt.Fprintf(out, " => %v %v\n", check_primes(res), s)
}
allres := [][]int{}
fn(*n, *k, func(res []int) {
print_res(res)
t := make([]int, len(res))
copy(t, res)
allres = append(allres, t)
})
if p := strings.TrimSpace(*path); p != "-" && p != "" {
fmt.Println()
fmt.Println()
}
for _, res := range allres {
print_res(res)
}
}
var verbose = !true
var debug = !true
func combin_primes(n, k int, cb func([]int)) {
ps := load_primes(n)
u := len(ps)
if debug {
fmt.Fprintln(os.Stderr, "n", n)
fmt.Fprintln(os.Stderr, "k", k)
fmt.Fprintln(os.Stderr, "u", u)
}
res := make([]int, k)
idx := make([]int, k)
for i := range idx {
idx[i] = i
}
idx[0]++
l := k - 1
c := 1
var best_sum int
var best_sumk1 int
for idx[0] <= u-k && (best_sumk1 < 1 || ps[idx[0]] <= best_sumk1) {
ok := valid_primes_pairs(ps, idx[:c], idx[c])
if debug {
if ok {
fmt.Fprintf(os.Stderr, "c=%v ", c)
fmt.Fprintf(os.Stderr, "idx=%-20v ", fmt.Sprint(idx[:c+1]))
fmt.Fprintf(os.Stderr, "primes=%v ", print_primes(ps, idx[:c+1]))
fmt.Fprintln(os.Stderr)
<-time.After(time.Second / (2 * 5))
}
}
if ok {
if c == l {
s := 0
for i, v := range idx {
res[i] = ps[v]
s += res[i]
}
if s >= n && (best_sum < 1 || best_sum >= s) {
best_sum = s
best_sumk1 = s / k
cb(res)
c--
}
} else {
c++
if c == l {
s := 0
for _, v := range idx[:c] {
s += ps[v]
}
n := sort.SearchInts(ps[idx[c]:], (n-s)/(k-c)) - 1
if n > idx[c-1] {
idx[c] = n
} else {
idx[c] = idx[c-1]
}
} else {
idx[c] = idx[c-1]
}
}
}
if !ok && c == l && best_sum > 0 {
s1 := 0
for _, v := range idx {
s1 += ps[v]
}
if s1 > best_sum {
c--
}
}
idx[c]++
// if c > 0 && res[c] > 0 && ps[idx[c]] >= res[c] {
// c--
// idx[c]++
// }
for c > 0 && idx[c] >= u-(k-c) {
c--
idx[c]++
}
if c == 0 {
c = 1
idx[c] = idx[c-1] + 1
if verbose {
fmt.Fprintln(os.Stderr, "....", ps[idx[0]])
}
}
}
}
var mutex sync.Mutex
var gbest_sum int
var gbest_sumk1 int
func combin_primes_mt(n, k int, cb func([]int)) {
ps := load_primes(n)
lmt := make(chan struct{}, 8)
c := make(chan []int, 10)
var wg sync.WaitGroup
wg.Add(1)
go func() {
defer wg.Done()
for i := 0; i < len(ps)-k; i++ {
wg.Add(1)
i := i
lmt <- struct{}{}
go func() {
defer wg.Done()
combin_primes_start(ps, i, n, k, func(r []int) {
t := make([]int, k)
copy(t, r)
c <- t
})
<-lmt
}()
}
}()
go func() {
wg.Wait()
close(c)
}()
for o := range c {
cb(o)
}
}
func combin_primes_start(ps []int, st, n, k int, cb func([]int)) {
u := len(ps)
if st > u-k {
return
}
if debug {
fmt.Fprintln(os.Stderr, "n", n)
fmt.Fprintln(os.Stderr, "k", k)
fmt.Fprintln(os.Stderr, "u", u)
}
res := make([]int, k)
idx := make([]int, k)
for i := range idx {
idx[i] = st + i
}
if st == 0 {
idx[0]++
}
l := k - 1
c := 1
mutex.Lock()
best_sum := gbest_sum
best_sumk1 := gbest_sumk1
mutex.Unlock()
for idx[0] <= u-k && (best_sumk1 < 1 || ps[idx[0]] <= best_sumk1) {
ok := valid_primes_pairs(ps, idx[:c], idx[c])
if debug {
if ok {
fmt.Fprintf(os.Stderr, "c=%v ", c)
fmt.Fprintf(os.Stderr, "idx=%-20v ", fmt.Sprint(idx[:c+1]))
fmt.Fprintf(os.Stderr, "primes=%v ", print_primes(ps, idx[:c+1]))
fmt.Fprintln(os.Stderr)
<-time.After(time.Second / (2 * 5))
}
}
if ok {
if c == l {
s := 0
for i, v := range idx {
res[i] = ps[v]
s += res[i]
}
if s >= n && (best_sum < 1 || best_sum >= s) {
best_sum = s
best_sumk1 = s / k
mutex.Lock()
if gbest_sum < 1 || best_sum < gbest_sum {
gbest_sum = best_sum
gbest_sumk1 = best_sumk1
}
mutex.Unlock()
cb(res)
c--
}
} else {
c++
if c == l {
s := 0
for _, v := range idx[:c] {
s += ps[v]
}
n := sort.SearchInts(ps[idx[c]:], (n-s)/(k-c)) - 1
if n > idx[c-1] {
idx[c] = n
} else {
idx[c] = idx[c-1]
}
} else {
idx[c] = idx[c-1]
}
}
}
if !ok && c == l && best_sum > 0 {
s1 := 0
for _, v := range idx {
s1 += ps[v]
}
if s1 > best_sum {
c--
}
}
idx[c]++
// if c > 0 && res[c] > 0 && ps[idx[c]] >= res[c] {
// c--
// idx[c]++
// }
for c > 0 && idx[c] >= u-(k-c) {
c--
idx[c]++
}
if c == 0 {
// c = 1
// idx[c] = idx[c-1] + 1
if verbose {
fmt.Fprintln(os.Stderr, "....", ps[idx[0]])
}
return
}
}
}
func check_primes(f []int) bool {
for i := 0; i < len(f)-1; i++ {
if k := concat(f[0], f[1]); !IsPrime(k) {
return false
}
if k := concat(f[1], f[0]); !IsPrime(k) {
return false
}
}
return true
}
func print_primes(ps []int, f []int) (s string) {
for i, j := range f {
if i+1 < len(f) {
s += fmt.Sprint(ps[j], ",")
} else {
s += fmt.Sprint(ps[j])
}
}
return
}
func valid_primes_pairs(ps []int, h []int, g int) bool {
for _, v := range h {
if k := concat(ps[v], ps[g]); !IsPrime(k) {
return false
}
if k := concat(ps[g], ps[v]); !IsPrime(k) {
return false
}
}
return true
}
func concat(left, right int) int {
i := 1
for i <= right {
i *= 10
}
left *= i
return left + right
}
func load_primes(n int) []int {
nn := message.NewPrinter(language.English).Sprintf("%d", n)
nn = strings.Replace(nn, ",", "_", -1)
name := fmt.Sprintf("primes_%v.txt", nn)
j := len(strconv.Itoa(n / 10))
st, err := os.Stat(name)
if os.IsNotExist(err) {
f, err := os.Create(name)
if err != nil {
panic(err)
}
defer f.Close()
dst := bufio.NewWriter(f)
defer dst.Flush()
z := fmt.Sprintf("%%%vv\n", j)
ps := primes.Sieve(n)
for _, p := range ps {
fmt.Fprintf(dst, z, p)
}
return ps
}
r, err := os.Open(name)
if err != nil {
panic(err)
}
k := st.Size() / int64(1+j)
sc := bufio.NewScanner(bufio.NewReader(r))
ps := make([]int, k)
var i int
for sc.Scan() {
t := strings.TrimSpace(sc.Text())
n, err := strconv.Atoi(t)
if err != nil {
panic(err)
}
ps[i] = n
i++
}
return ps
}
// primes is a cache of the first few prime numbers
var primes_cache []int
func IsPrime(n int) bool {
pMax := primes_cache[len(primes_cache)-1]
if n <= pMax {
// If n is prime, it must be in the cache
i := sort.SearchInts(primes_cache, n)
return n == primes_cache[i]
}
return primes.IsPrime(n)
} |
Recherche de nombres premiers satisfaisant certains critères
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