mashiike / comb

combination library

comb

This library provides the ability to split Slice elements into multiple groups.
The approach is to solve combinatorial optimization problems by minimizing the energy function.

Usage

The interface is similar to sort.Slice. It can be used as the following example.

target := []float64{1.0, 2.0, 3.0, 3.5, 4.0, 3.8}
score := func(ind []int) float64 {
	total := 0.0
	for _, i := range ind {
		total += target[i]
	}
	return total
}
energy := func(inds [][]int) float64 {
	var min, max float64
	for _, ind := range inds {
		s := score(ind)
		if min > s {
			min = s
		}
		if max < s {
			max = s
		}
	}
	return (max - min) * (max - min)
}
groups := comb.Slice(target, 4, energy)

for _, group := range groups {
	fmt.Printf("[")
	for _, i := range group {
		fmt.Printf(" %f ", target[i])
	}
	fmt.Printf("] => %f\n", score(group))
}
//Output:
//[ 1.000000  3.800000 ] => 4.800000
//[ 2.000000  3.000000 ] => 5.000000
//[ 3.500000 ] => 3.500000
//[ 4.000000 ] => 4.000000