package chromem

import "math"

func cosine_similarities(a, b [][]float32) [][]float32 {
	result := make([][]float32, len(a))
	for iX, x := range a {
		result[iX] = make([]float32, len(b))
		for iY, y := range b {
			result[iX][iY] = cosine_similarity(x, y)
		}
	}
	return result
}

func cosine_similarity(x, y []float32) float32 {
	var sum, s1, s2 float64
	for i := 0; i < len(x); i++ {
		sum += float64(x[i] * y[i])
		s1 += math.Pow(float64(x[i]), 2)
		s2 += math.Pow(float64(y[i]), 2)
	}
	if s1 == 0 || s2 == 0 {
		return 0.0
	}
	return float32(sum / (math.Sqrt(s1) * math.Sqrt(s2)))
}