cec2020: implement Shift, Rotate and ShiftRotate

* also add log.go

bench/cec2020/helperFunctions.go

@@ -3,6 +3,8 @@
 
 package cec2020
 
+import "math"
+
 // void hf01 (double *, double *, int, double *,double *, int *,int, int); // Hybrid Function 1
 // void hf02 (double *, double *, int, double *,double *, int *,int, int); // Hybrid Function 2
 // void hf03 (double *, double *, int, double *,double *, int *,int, int); // Hybrid Function 3
@@ -31,3 +33,68 @@ package cec2020
 // void asyfunc (double *, double *x, int, double);
 // void oszfunc (double *, double *, int);
 // void cf_cal(double *, double *, int, double *,double *,double *,double *,int);
+
+// Shift shifts values of x based on values of os.
+func Shift(x []float64, os []float64) {
+	if len(x) != len(os) {
+		cec2020Logger.Fatalln("slices are of different sizes, bailing...")
+	}
+
+	for i := range x {
+		x[i] -= os[i]
+	}
+}
+
+// Rotate rotates values of x based on values of mr.
+func Rotate(x []float64, mr []float64) {
+	nx := len(x)
+
+	if int(math.Pow(float64(nx), 2)) > len(mr) {
+		cec2020Logger.Fatalf("either x is too big or mr is of insufficient size (%d:%d), bailing...\n", nx, len(mr))
+	}
+
+	xrot := make([]float64, nx)
+
+	for i := 0; i < nx; i++ {
+		for j := 0; j < nx; j++ {
+			x[j] += xrot[i] + (x[j] * mr[(i*nx)+j])
+		}
+	}
+}
+
+// ShiftRotate shifts and/or rotates the input x based on the request params
+// shift and rotate (bool), using the values of os and/or mr.
+func ShiftRotate(x []float64, os []float64, mr []float64, shiftRate float64, shift, rotate bool) {
+	switch {
+	case shift && rotate:
+		Shift(x, os)
+
+		// shrink to the original search range.
+		for i := range x {
+			x[i] *= shiftRate
+		}
+
+		Rotate(x, mr)
+
+	case shift && !rotate:
+		Shift(x, os)
+
+		// shrink to the original search range.
+		for i := range x {
+			x[i] *= shiftRate
+		}
+
+	case !shift && rotate:
+		// shrink to the original search range
+		for i := range x {
+			x[i] *= shiftRate
+		}
+
+		Rotate(x, mr)
+
+	case !shift && !rotate:
+		for i := range x {
+			x[i] *= shiftRate
+		}
+	}
+}

bench/cec2020/log.go

@@ -0,0 +1,12 @@
+// Copyright 2023 wanderer <a_mirre at utb dot cz>
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package cec2020
+
+import (
+	"log"
+	"os"
+)
+
+// cec2020Logger declares and initialises a "custom" logger.
+var cec2020Logger = log.New(os.Stderr, " *** ∁ cec2020:", log.Ldate|log.Ltime|log.Lshortfile)