cec2020: add asymptotic func

bench/cec2020/helperFunctions.go

@@ -98,3 +98,17 @@ func ShiftRotate(x []float64, os []float64, mr []float64, shiftRate float64, shi
 		}
 	}
 }
+
+// Asy is the asymptotic function.
+func Asy(x []float64, beta float64) {
+	nx := len(x)
+
+	for i := range x {
+		if x[i] > 0 {
+			fi := float64(i)
+			fnx := float64(nx)
+
+			x[i] = math.Pow(x[i], 1+((beta*fi)/(fnx-1)*math.Pow(x[i], 0.5)))
+		}
+	}
+}