go: add bench funcs

* Schwefel
* 1st De Jong
* 2nd De Jong

bench/bench.go

@@ -0,0 +1,59 @@
+// Copyright 2022 wanderer <a_mirre at utb dot cz>
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package bench
+
+import "math"
+
+type funcParams struct {
+	min float64
+	max float64
+}
+
+const (
+	Neighbourhood = 10
+	// MaxFES is the maximum number of allowed function evaluations.
+	MaxFES = 10000
+)
+
+var (
+	// Dimensions to compute for (spatial complexity..?).
+	Dimensions = []int{5, 10, 20}
+
+	SchwefelParams = funcParams{min: -500.0, max: 500.0}
+	DeJong1Params  = funcParams{min: -5.0, max: 5.0}
+	DeJong2Params  = funcParams{min: -5.0, max: 5.0}
+)
+
+// Schwefel computes a value of the Schwefel function for x.
+func Schwefel(x []float64) float64 {
+	var res float64
+
+	for _, val := range x {
+		res += val * math.Sin(math.Sqrt(math.Abs(val)))
+	}
+
+	return 418.9829*float64(len(x)) - res
+}
+
+// DeJong1st computes the value of the 1st De Jong function for x.
+func DeJong1st(x []float64) float64 {
+	var res float64
+
+	for _, val := range x {
+		res += math.Floor(val)
+	}
+
+	return res
+}
+
+// DeJong2nd computes the value of the 2nd De Jong function for x.
+func DeJong2nd(x []float64) float64 {
+	var res float64
+
+	for _, val := range x {
+		res += math.Pow(val, 2)
+	}
+
+	return res
+}