binary-trees Go #2 program

/* The Computer Language Benchmarks Game
 * https://salsa.debian.org/benchmarksgame-team/benchmarksgame/
 *
 * contributed by The Go Authors.
 * based on C program by Kevin Carson
 * flag.Arg hack by Isaac Gouy
 * 
 * 2013-04
 * modified by Jamil Djadala to use goroutines
 * *reset*
 */

package main

import (
   "flag"
   "fmt"
   "strconv"
   "runtime"
   "sync"
)

var n = 0

type Node struct {
     left, right   *Node
}

func  bottomUpTree(depth int) *Node {
   if depth <= 0 {
      return &Node{}
   }
   return &Node{ bottomUpTree(depth-1), bottomUpTree(depth-1) }
}

func (n *Node) itemCheck() int {
   if n.left == nil {
      return 1
   }
   return 1 + n.left.itemCheck() + n.right.itemCheck()
}

const minDepth = 4

func main() {  
   runtime.GOMAXPROCS( runtime.NumCPU() + 2)
 
   flag.Parse()
   if flag.NArg() > 0 { n,_ = strconv.Atoi( flag.Arg(0) ) }

   maxDepth := n
   if minDepth + 2 > n {
      maxDepth = minDepth + 2
   }
   stretchDepth := maxDepth + 1

   check_l := bottomUpTree(stretchDepth).itemCheck()
   fmt.Printf("stretch tree of depth %d\t check: %d\n", stretchDepth, check_l)

   longLivedTree := bottomUpTree(maxDepth)
   
   var wg sync.WaitGroup
   result := make( []string, maxDepth+1)

   for depth_l := minDepth; depth_l <= maxDepth; depth_l+=2 {
          wg.Add(1)
          go func( depth int, check int, r *string) {
          defer wg.Done()    
          iterations := 1 << uint(maxDepth - depth + minDepth)
          check = 0

          for i := 1; i <= iterations; i++ {
             check += bottomUpTree(depth).itemCheck()
          }
          *r = fmt.Sprintf("%d\t trees of depth %d\t check: %d", iterations, depth, check)
       }( depth_l, check_l, &result[depth_l])
   }
   wg.Wait()
   for depth := minDepth; depth <= maxDepth; depth+=2 {
       fmt.Println( result[depth])
   }
   fmt.Printf("long lived tree of depth %d\t check: %d\n", maxDepth, longLivedTree.itemCheck())
   
}

    

NOTES:
64-bit Ubuntu quad core
go version go1.14 linux/amd64


Wed, 06 May 2020 00:29:33 GMT

MAKE:
/opt/src/go1.14.linux-amd64/go/bin/go build -o binarytrees.go-2.go_run

5.67s to complete and log all make actions

COMMAND LINE:
./binarytrees.go-2.go_run 21

PROGRAM OUTPUT:
stretch tree of depth 22	 check: 8388607
2097152	 trees of depth 4	 check: 65011712
524288	 trees of depth 6	 check: 66584576
131072	 trees of depth 8	 check: 66977792
32768	 trees of depth 10	 check: 67076096
8192	 trees of depth 12	 check: 67100672
2048	 trees of depth 14	 check: 67106816
512	 trees of depth 16	 check: 67108352
128	 trees of depth 18	 check: 67108736
32	 trees of depth 20	 check: 67108832
long lived tree of depth 21	 check: 4194303