feat: add Log function

mathutil/mathutil.go

@@ -323,3 +323,9 @@ func Cos(radian float64, precision ...int) float64 {
 func Sin(radian float64, precision ...int) float64 {
 	return Cos((math.Pi / 2) - radian)
 }
+
+// Log retur the logarithm of base n.
+// Play: todo
+func Log(n, base float64) float64 {
+	return math.Log(n) / math.Log(base)
+}

mathutil/mathutil_exmaple_test.go

@@ -362,3 +362,18 @@ func ExampleSin() {
 	// 0
 	// 1
 }
+
+func ExampleLog() {
+	result1 := Log(8, 2)
+	result2 := TruncRound(Log(5, 2), 2)
+	result3 := TruncRound(Log(27, 3), 0)
+
+	fmt.Println(result1)
+	fmt.Println(result2)
+	fmt.Println(result3)
+
+	// Output:
+	// 3
+	// 2.32
+	// 3
+}

mathutil/mathutil_test.go

@@ -269,3 +269,11 @@ func TestSin(t *testing.T) {
 	assert.EqualValues(0, Sin(math.Pi))
 	assert.EqualValues(1, Sin(math.Pi/2))
 }
+
+func TestLog(t *testing.T) {
+	assert := internal.NewAssert(t, "TestLog")
+
+	assert.EqualValues(3, Log(8, 2))
+	assert.EqualValues(3, TruncRound(Log(27, 3), 0))
+	assert.EqualValues(2.32, TruncRound(Log(5, 2), 2))
+}