math-optim/bench/cec2020/helperFunctions.go

// Copyright 2023 wanderer <a_mirre at utb dot cz>
// SPDX-License-Identifier: GPL-3.0-or-later

package cec2020

import (
	"math"
	"time"

	"golang.org/x/exp/rand"

	"gonum.org/v1/gonum/stat/distuv"
)

// 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
// void hf04 (double *, double *, int, double *,double *, int *,int, int); // Hybrid Function 4
// void hf05 (double *, double *, int, double *,double *, int *,int, int); // Hybrid Function 5
// void hf06 (double *, double *, int, double *,double *, int *,int, int); // Hybrid Function 6
// void hf07 (double *, double *, int, double *,double *, int *,int, int); // Hybrid Function 7
// void hf08 (double *, double *, int, double *,double *, int *,int, int); // Hybrid Function 8
// void hf09 (double *, double *, int, double *,double *, int *,int, int); // Hybrid Function 9
// void hf10 (double *, double *, int, double *,double *, int *,int, int); // Hybrid Function 10
//
// void cf01 (double *, double *, int , double *,double *, int); // Composition Function 1
// void cf02 (double *, double *, int , double *,double *, int); // Composition Function 2
// void cf03 (double *, double *, int , double *,double *, int); // Composition Function 3
// void cf04 (double *, double *, int , double *,double *, int); // Composition Function 4
// void cf05 (double *, double *, int , double *,double *, int); // Composition Function 5
// void cf06 (double *, double *, int , double *,double *, int); // Composition Function 6
// void cf07 (double *, double *, int , double *,double *, int); // Composition Function 7
// void cf08 (double *, double *, int , double *,double *, int); // Composition Function 8
// void cf09 (double *, double *, int , double *,double *, int *, int); // Composition Function 9/
// void cf10 (double *, double *, int , double *,double *, int *, int); // Composition Function 10

// void shiftfunc (double*,double*,int,double*);
// void rotatefunc (double*,double*,int, double*);
// void sr_func (double *, double *, int, double*, double*, double, int, int); // shift and rotate
// 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
		}
	}
}

// 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)))
		}
	}
}

func newXopt(n int, mu0 float64) []float64 {
	gaussDist := &distuv.Uniform{
		Src: rand.NewSource(uint64(time.Now().UnixNano())),
		Min: SearchRange.Min(),
		Max: SearchRange.Max(),
	}

	tmpvec := make([]float64, n)
	xopt := make([]float64, n)

	for i := 0; i < n; i++ {
		tmpvec = append(tmpvec, gaussDist.Rand())

		xopt = append(xopt, 0.5*mu0)

		if tmpvec[i] < 0 {
			xopt[i] *= -1
		}
	}

	return xopt
}