Docs and bench

README.md

@@ -138,14 +138,21 @@ Here NSet finishes in `0.1ms` but Map takes almost a second with `813ms`.
 ![Benchmarking IsEq with 10,000,000 elements](./.res/bench-is-equal-10-million.png)
 
 Next we have `GetAllElements`, which simply returns an array of all the elements of NSet/Map (note this is dangerous in NSet. See [Memory characteristics](#memory-characteristics)).
-![Benchmarking GetAllElements with 1,000,000 elements](.res/bench-getAllElements-1-million.png)
+![Benchmarking GetAllElements with 10,000,000 elements](.res/bench-getAllElements-10-million.png)
 
-With `GetAllElements` NSet is faster when its elements are closer together (or you have many numbers), but gets a lot slower when
+With `GetAllElements` NSet is faster when its elements are closer together value wise (or if you have many numbers), but gets a lot slower when
-dealing with a few random numbers. This is because you might get two numbers like `1` and `1_000_000` which NSet
+dealing with a few random numbers with a big difference between them. This is because you might get two numbers like `1` and `1_000_000` which NSet
 will store in two far away places with a lot of nothing in between. In a map these will be stored close together.
 
-With 1M ordered elements NSet takes `~2ms` and map `~9ms`, but with a random 1M elements NSet takes `~129ms`
+With 10M ordered elements NSet takes `~31ms` and map `~97ms`, but with a random 10M elements NSet takes `~525ms`
-while map takes `~9ms`. Map scales with the amount of elements, while NSet is affected by number distribution as well.
+while map takes `~95ms`. Map scales with the amount of elements, while NSet is affected by number distribution as well.
+
+Similar to getting elements is intersection:
+
+![Benchmarking GetIntersection with 10,000,000 elements](.res/bench-getIntersection-10-million.png)
+
+Here NSet is always many times faster, but the effect of number distribution on NSet's performance is clear, while map's performance
+only scales with number of elements.
 
 ## How NSet works
 

nset_test.go

@@ -447,6 +447,8 @@ func BenchmarkMapIsEq(b *testing.B) {
 	}
 }
 
+var getIntersectionNset *nset.NSet[uint32]
+
 func BenchmarkNSetGetIntersection(b *testing.B) {
 
 	b.StopTimer()
@@ -459,7 +461,93 @@ func BenchmarkNSetGetIntersection(b *testing.B) {
 	b.StartTimer()
 
 	for i := 0; i < b.N; i++ {
-		s1.GetIntersection(s2)
+		getIntersectionNset = s1.GetIntersection(s2)
+	}
+}
+
+var getIntersectionTempMap map[uint32]struct{}
+
+func BenchmarkMapGetIntersection(b *testing.B) {
+
+	b.StopTimer()
+	m1 := map[uint32]struct{}{}
+	m2 := map[uint32]struct{}{}
+	for i := uint32(0); i < maxBenchSize; i++ {
+		m1[i] = struct{}{}
+		m2[i] = struct{}{}
+	}
+	b.StartTimer()
+
+	getIntersection := func(m1, m2 map[uint32]struct{}) map[uint32]struct{} {
+
+		outMap := map[uint32]struct{}{}
+
+		for k := range m1 {
+			if _, ok := m2[k]; ok {
+				outMap[k] = struct{}{}
+			}
+		}
+
+		return outMap
+	}
+
+	for i := 0; i < b.N; i++ {
+		getIntersectionTempMap = getIntersection(m1, m2)
+	}
+}
+
+func BenchmarkNSetGetIntersectionRand(b *testing.B) {
+
+	b.StopTimer()
+
+	rand.Seed(RandSeed)
+
+	s1 := nset.NewNSet[uint32]()
+	s2 := nset.NewNSet[uint32]()
+	for i := uint32(0); i < maxBenchSize; i++ {
+
+		r := rand.Uint32()
+		s1.Add(r)
+		s2.Add(r)
+	}
+	b.StartTimer()
+
+	for i := 0; i < b.N; i++ {
+		getIntersectionNset = s1.GetIntersection(s2)
+	}
+}
+
+func BenchmarkMapGetIntersectionRand(b *testing.B) {
+
+	b.StopTimer()
+
+	rand.Seed(RandSeed)
+
+	m1 := map[uint32]struct{}{}
+	m2 := map[uint32]struct{}{}
+	for i := uint32(0); i < maxBenchSize; i++ {
+
+		r := rand.Uint32()
+		m1[r] = struct{}{}
+		m2[r] = struct{}{}
+	}
+	b.StartTimer()
+
+	getIntersection := func(m1, m2 map[uint32]struct{}) map[uint32]struct{} {
+
+		outMap := map[uint32]struct{}{}
+
+		for k := range m1 {
+			if _, ok := m2[k]; ok {
+				outMap[k] = struct{}{}
+			}
+		}
+
+		return outMap
+	}
+
+	for i := 0; i < b.N; i++ {
+		getIntersectionTempMap = getIntersection(m1, m2)
 	}
 }
 
@@ -470,7 +558,7 @@ func BenchmarkNSetGetAllElements(b *testing.B) {
 	b.StopTimer()
 
 	s1 := nset.NewNSet[uint32]()
-	for i := uint32(0); i < 1000_000; i++ {
+	for i := uint32(0); i < 10_000_000; i++ {
 		s1.Add(i)
 	}
 	b.StartTimer()
@@ -488,7 +576,7 @@ func BenchmarkMapGetAllElements(b *testing.B) {
 	b.StopTimer()
 
 	m1 := map[uint32]struct{}{}
-	for i := uint32(0); i < 1000_000; i++ {
+	for i := uint32(0); i < 10_000_000; i++ {
 		m1[i] = struct{}{}
 	}
 	b.StartTimer()
@@ -517,7 +605,7 @@ func BenchmarkNSetGetAllElementsRand(b *testing.B) {
 
 	rand.Seed(RandSeed)
 	s1 := nset.NewNSet[uint32]()
-	for i := uint32(0); i < 1000_000; i++ {
+	for i := uint32(0); i < 10_000_000; i++ {
 		s1.Add(rand.Uint32())
 	}
 	b.StartTimer()
@@ -537,7 +625,7 @@ func BenchmarkMapGetAllElementsRand(b *testing.B) {
 	rand.Seed(RandSeed)
 
 	m1 := map[uint32]struct{}{}
-	for i := uint32(0); i < 1000_000; i++ {
+	for i := uint32(0); i < 10_000_000; i++ {
 		m1[rand.Uint32()] = struct{}{}
 	}