func (s LScores) score(l Label) float32 {
vsc, ok := s[string(l)]
if !ok {
return 0
}
sc, _ := data.AsFloat(vsc)
return float32(sc)
}
func mapToValues(v data.Map) ([]float64, error) {
values := make([]float64, 0, len(v))
for _, x := range v {
val, err := data.AsFloat(x)
if err != nil {
return nil, err
}
values = append(values, val)
}
return values, nil
}
// maxLabelScore returns the max score and its label in a data.Map.
// This function are same as LScores.Max() except error checking.
func maxLabelScore(scores data.Map) (label string, score float64, err error) {
if len(scores) == 0 {
err = errors.New("attempt to find a max score from an empty map")
return "", 0, err
}
score = minusInf
for l, s := range scores {
sc, err := data.AsFloat(s)
if err != nil {
err = fmt.Errorf("score for %s is not a float: %v", l, err)
return "", 0, err
}
if sc > score {
label = l
score = sc
}
}
return label, score, nil
}
// Softmax calculates softmax.
func Softmax(v data.Map) (data.Map, error) {
ret := make(data.Map)
if len(v) == 0 {
return ret, nil
}
// copy values to an array to sort in logSumExp().
values, err := mapToValues(v)
if err != nil {
return nil, err
}
lse := logSumExp(values)
for k, x := range v {
val, err := data.AsFloat(x)
if err != nil {
return nil, err
}
ret[k] = data.Float(math.Exp(val - lse))
}
return ret, nil
}
func toFloat(d data.Value) float64 {
ret, _ := data.AsFloat(d)
return ret
}
