/
gperfect.go
94 lines (83 loc) · 2.39 KB
/
gperfect.go
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package main
import (
"flag"
"fmt"
"math/rand"
"time"
)
func main() {
defer trace("gperfect")()
perPtr := flag.Uint64("number", 0, "Perfect number to find")
coreCountPtr := flag.Uint("numCores", 8, "Number of cores to use when calculating random perfect numbers")
numRandPtr := flag.Uint("numRandom", 100, "Number of random perfect numbers to look for. Omit for continuous calculations")
flag.Parse()
if *perPtr > 0 {
calcPerfect(*perPtr, *coreCountPtr)
} else {
calcRandPerfects(coreCountPtr, numRandPtr)
}
}
func calcPerfect(uNumTest uint64, uNumCores uint) {
var uCalc uint64
var i uint64
uHalf := uNumTest / 2
// If the domain of possible numbers is > 100,000,000 then split it up on multiple threads
if uNumTest < 100000000 {
for i = 1; i <= uHalf; i++ {
if uNumTest%i == 0 {
uCalc += i
}
}
} else {
// chans := make(chan uint64, uNumCores)
var uChan uint
var uLeftOver = uHalf % uint64(uNumCores)
var uChunkStart uint64 = 1
var chans []chan uint64
uInterval := uHalf / uint64(uNumCores)
uChunkEnd := uLeftOver
for uChan = 0; uChan < uNumCores; uChan++ {
chans = append(chans, make(chan uint64))
uChunkEnd += uInterval
go calcProc(uChan, uNumTest, uChunkStart, uChunkEnd, chans[uChan])
uChunkStart = uChunkEnd + 1
}
for uChan = 0; uChan < uNumCores; uChan++ {
fmt.Printf("uChan=%d, uCalc=%d\n", uChan, uCalc)
uCalc += <-chans[uChan]
}
}
if uCalc == uNumTest {
fmt.Printf("%d,PERFECT\n", uNumTest)
} else {
fmt.Printf("%d,not perfect\n", uNumTest)
}
}
func calcProc(uTmpChan uint, uTmpNumTest uint64, uChunkStart uint64, uChunkEnd uint64, chans chan (uint64)) {
fmt.Printf("%d: PROC STARTED -start=%d, end=%d\n", uTmpChan, uChunkStart, uChunkEnd)
var uTmp uint64
for i := (uChunkStart + 1); i <= uChunkEnd; i++ {
//fmt.Printf("chan=%d, idx=%d\n", uTmpChan, i)
if uTmpNumTest%i == 0 {
uTmp += i
}
}
fmt.Printf("DONE - %d; val=%d\n", uTmpChan, uTmp)
chans <- uTmp
}
func calcRandPerfects(coureCountPtr *uint, numRandPtr *uint) {
var i uint
uMax := *numRandPtr
r := rand.New(rand.NewSource(time.Now().UnixNano()))
for i = 0; i < uMax; i++ {
calcPerfect(uint64(r.Int31()), *coureCountPtr)
}
}
func trace(msg string) func() {
start := time.Now()
fmt.Printf("%s started at: %s\n", msg, start.Local())
return func() {
end := time.Now()
fmt.Printf("%s finished at: %s; elapsed time: %s\n", msg, end.Local(), end.Sub(start))
}
}