add : Parallel Odd-Even Merge Sort

Author: kdgyun

README.md

@@ -201,6 +201,7 @@ Algorithms covered so far:
 | [Cycle Sort](#cycle-sort) | CycleSort |
 | [Odd-Even Sort](#odd-even-sort) | OddEvenSort |
 | [Odd-Even Merge Sort](#odd-even-merge-sort) | OddEvenMergeSort |
+| [Odd-Even Merge Sort (parallel)](#odd-even-merge-sort) | ParallelOddEvenMergeSort |
 
 
 <br />
@@ -579,7 +580,7 @@ and depth
 <span> ![O((log_n)^2)](https://latex.codecogs.com/svg.image?O((\log&space;n)^2)) </span> 
 where n is the number of items to be sorted.    
 
-\[todo] add parallel-ver.
+
 
 
 <br />

glob_bench_test/sort_bench_test.go

@@ -364,3 +364,16 @@ func BenchmarkOddEvenMergeSort(b *testing.B) {
 		b.StopTimer()
 	}
 }
+
+func BenchmarkParallelOddEvenMergeSort(b *testing.B) {
+	b.StopTimer()
+	unsorted := sliceBuilder(lengthforbench)
+	test := make([]int, len(unsorted))
+
+	for i := 0; i < b.N; i++ {
+		copy(test, unsorted)
+		b.StartTimer()
+		sorts.ParallelOddEvenMergeSort(test)
+		b.StopTimer()
+	}
+}

glob_bench_test/sort_test.go

@@ -220,6 +220,14 @@ func TestSort(t *testing.T) {
 		if !reflect.DeepEqual(test, verify) {
 			t.Error("Wrong result [odd-even sort]")
 		}
+
+		test = make([]int, len(origin))
+		copy(test, origin)
+		t.Run("parallel odd-even merge sort", func(t *testing.T) { sorts.ParallelOddEvenMergeSort(test) })
+
+		if !reflect.DeepEqual(test, verify) {
+			t.Error("Wrong result [parallel odd-even sort]")
+		}
 		size <<= 2
 	}
 }

simplytest/base_sort_list.go

@@ -368,7 +368,7 @@ func CallOddEvenSort(origin []int, verify []int, callName string) OutputForm {
 func CallOddEvenMergeSort(origin []int, verify []int, callName string) OutputForm {
 	size := len(origin)
 	if (size & (size - 1)) != 0 {
-		fmt.Println(aurora.Bold(aurora.BrightRed("[Skip] ")), aurora.BrightRed("top-down odd-even sort can't run"))
+		fmt.Println(aurora.Bold(aurora.BrightRed("[Skip] ")), aurora.BrightRed("odd-even sort can't run"))
 		fmt.Println(aurora.BrightYellow("\tIf you want to use this sort algorithm,\n\tlength of the array must be a power of 2."))
 		return OutputForm{false, callName, -1, false, ""}
 	}
@@ -384,3 +384,23 @@ func CallOddEvenMergeSort(origin []int, verify []int, callName string) OutputFor
 	}
 	return OutputForm{false, callName, -1, false, ""}
 }
+
+func CallParallelOddEvenMergeSort(origin []int, verify []int, callName string) OutputForm {
+	size := len(origin)
+	if (size & (size - 1)) != 0 {
+		fmt.Println(aurora.Bold(aurora.BrightRed("[Skip] ")), aurora.BrightRed("parallel odd-even sort can't run"))
+		fmt.Println(aurora.BrightYellow("\tIf you want to use this sort algorithm,\n\tlength of the array must be a power of 2."))
+		return OutputForm{false, callName, -1, false, ""}
+	}
+	if PARALLEL_ODDEVEN_MERGE_SORT {
+		test := make([]int, len(origin))
+		copy(test, origin)
+		fmt.Printf("runing %s...\n", callName)
+		start := time.Now()
+		sorts.ParallelOddEvenMergeSort(test)
+		end := time.Since(start)
+		eq, err := Equal(verify, test)
+		return OutputForm{true, callName, end.Nanoseconds(), eq, err}
+	}
+	return OutputForm{false, callName, -1, false, ""}
+}

simplytest/option.go

@@ -38,6 +38,7 @@ const (
 	CYCLE_SORT                       Activate = true
 	ODDEVEN_SORT                     Activate = true
 	ODDEVEN_MERGE_SORT               Activate = true // The length n of the array must be a power of 2
+	PARALLEL_ODDEVEN_MERGE_SORT      Activate = true // The length n of the array must be a power of 2
 )
 
 // Section 2.

simplytest/test_run.go

@@ -53,6 +53,7 @@ func callSortTest(origin, verify []int) {
 	q = append(q, CallCycleSort(origin, verify, "cycle sort"))
 	q = append(q, CallOddEvenSort(origin, verify, "odd-even sort"))
 	q = append(q, CallOddEvenMergeSort(origin, verify, "odd-even merge sort"))
+	q = append(q, CallParallelOddEvenMergeSort(origin, verify, "parallel odd-even merge sort"))
 	var pf string = ""
 
 	pf += fmt.Sprintf("\n+%s+\n", strings.Repeat("-", 97))

sorts/bitonic_sort.go

@@ -43,18 +43,3 @@ func greatestPowerOfTwoLessThan(n int) int {
 	}
 	return k >> 1
 }
-func BottomUpBitonicSort(a []int) {
-
-}
-
-func bottomUpBitonicSort(a []int, len int) {
-
-	for blockSize := 2; blockSize <= len; blockSize <<= 1 {
-		for subPart := blockSize / 2; subPart > 0; subPart >>= 1 {
-
-			for i := 0; i < len; i++ {
-
-			}
-		}
-	}
-}

sorts/parallel_odd_even_merge_sort.go

@@ -0,0 +1,100 @@
+/*
+  author : kdgyun
+
+  link : https://st-lab.tistory.com
+  link : https://github.com/kdgyun
+*/
+
+package sorts
+
+import (
+	"runtime"
+	"sync"
+)
+
+func ParallelOddEvenMergeSort(a []int) {
+	runtime.GOMAXPROCS(runtime.NumCPU())
+	parallelOddEvenMergeSort(a, 0, len(a))
+}
+
+func parallelOddEvenMergeSort(a []int, lo, hi int) {
+	if hi-lo > 1 {
+		mid := (hi + lo) >> 1
+		// 2048 is threshold
+		if hi-lo > 2048 {
+
+			var wg sync.WaitGroup
+			wg.Add(1)
+
+			go func() {
+				defer wg.Done()
+				parallelOddEvenMergeSort(a, lo, mid)
+			}()
+			parallelOddEvenMergeSort(a, mid, hi)
+			wg.Wait()
+			parallelOddEvenMerge(a, lo, hi, 1)
+		} else {
+			basicOddEvenMergeSort(a, lo, mid)
+			basicOddEvenMergeSort(a, mid, hi)
+			basicOddEvenMerge(a, lo, hi, 1)
+		}
+	}
+}
+
+func parallelOddEvenMerge(a []int, lo, hi, dist int) {
+	subDist := dist << 1
+	if subDist < (hi - lo) {
+
+		if subDist < 32 {
+			var wg sync.WaitGroup
+			wg.Add(1)
+
+			go func() {
+				defer wg.Done()
+				parallelOddEvenMerge(a, lo, hi, subDist)
+			}()
+			parallelOddEvenMerge(a, lo+dist, hi, subDist)
+			wg.Wait()
+		} else {
+			basicOddEvenMerge(a, lo, hi, subDist)
+			basicOddEvenMerge(a, lo+dist, hi, subDist)
+		}
+		for i := lo + dist; i+dist < hi; i += subDist {
+
+			if a[i] > a[i+dist] {
+				a[i], a[i+dist] = a[i+dist], a[i]
+			}
+		}
+	} else {
+		if a[lo] > a[lo+dist] {
+			a[lo], a[lo+dist] = a[lo+dist], a[lo]
+		}
+	}
+}
+
+func basicOddEvenMergeSort(a []int, lo, hi int) {
+	if hi-lo > 1 {
+		mid := (hi + lo) >> 1
+		basicOddEvenMergeSort(a, lo, mid)
+		basicOddEvenMergeSort(a, mid, hi)
+		basicOddEvenMerge(a, lo, hi, 1)
+	}
+}
+
+func basicOddEvenMerge(a []int, lo, hi, dist int) {
+	subDist := dist << 1
+	if subDist < (hi - lo) {
+		basicOddEvenMerge(a, lo, hi, subDist)
+		basicOddEvenMerge(a, lo+dist, hi, subDist)
+		for i := lo + dist; i+dist < hi; i += subDist {
+
+			if a[i] > a[i+dist] {
+				a[i], a[i+dist] = a[i+dist], a[i]
+			}
+		}
+	} else {
+		if a[lo] > a[lo+dist] {
+			a[lo], a[lo+dist] = a[lo+dist], a[lo]
+		}
+	}
+}