/*
ComputeContinu Given an attribute A and the target attribute T which contain
N classes in C, compute the information gain of A.
The result of Gini partitions value, Gini Index, and Gini Gain is saved in
ContinuPart, Index, and Gain.
*/
func (gini *Gini) ComputeContinu(A *[]float64, T *[]string, C *[]string) {
gini.IsContinu = true
// make a copy of attribute and target.
A2 := make([]float64, len(*A))
copy(A2, *A)
T2 := make([]string, len(*T))
copy(T2, *T)
gini.SortedIndex = numerus.Floats64IndirectSort(A2, true)
if DEBUG >= 1 {
fmt.Println("[gini] attr sorted :", A2)
}
// sort the target attribute using sorted index.
tekstus.StringsSortByIndex(&T2, gini.SortedIndex)
// create partition
gini.createContinuPartition(&A2)
// create holder for gini index and gini gain
gini.Index = make([]float64, len(gini.ContinuPart))
gini.Gain = make([]float64, len(gini.ContinuPart))
gini.MinIndexValue = 1.0
// compute gini index for all samples
gini.Value = gini.compute(&T2, C)
gini.computeContinuGain(&A2, &T2, C)
}
//
// ComputeContinuFloat Given an attribute A and the target attribute T which contain
// N classes in C, compute the information gain of A.
//
// The result of Gini partitions value, Gini Index, and Gini Gain is saved in
// ContinuPart, Index, and Gain.
//
// Algorithm,
// (0) Sort the attribute.
// (1) Sort the target attribute using sorted index.
// (2) Create continu partition.
// (3) Create temporary space for gini index and gini gain.
// (4) Compute gini index for all target.
//
func (gini *Gini) ComputeContinuFloat(A, T, C *[]float64) {
gini.IsContinu = true
gini.SortedIndex = numerus.Floats64IndirectSort(*A, true)
if DEBUG >= 1 {
fmt.Println("[gini] attr sorted :", A)
}
// (1)
numerus.Floats64SortByIndex(T, gini.SortedIndex)
// (2)
gini.createContinuPartition(A)
// (3)
gini.Index = make([]float64, len(gini.ContinuPart))
gini.Gain = make([]float64, len(gini.ContinuPart))
gini.MinIndexValue = 1.0
// (4)
gini.Value = gini.computeFloat(T, C)
gini.computeContinuGainFloat(A, T, C)
}
