elliotchance/gedcom

package gedcom

import "fmt"

// SurroundingSimilarity describes different aspects of the similarity of an
// individual by its immediate relationships; parents, spouses and children.
type SurroundingSimilarity struct {
    // ParentsSimilarity is the similarity of the fathers and mothers of the
    // individual. Each missing parent will be given 0.5. If both parents are
    // missing the parent similarity will also be 0.5.
    //
    // An individual can have zero or more pairs of parents, but only a single
    // ParentsSimilarity is provided. The ParentsSimilarity is the highest value
    // when each of the parents are compared with the other parents of the other
    // individual.
    ParentsSimilarity float64

    // IndividualSimilarity is the same as Individual.Similarity().
    IndividualSimilarity float64

    // SpousesSimilarity is the similarity of the spouses is compared with
    // IndividualNodes.Similarity() which is designed to compare several
    // individuals at once. It also handles comparing a different number of
    // individuals on either side.
    SpousesSimilarity float64

    // ChildrenSimilarity also uses IndividualNodes.Similarity() but without
    // respect to their parents (which in this case would be the current
    // individual and likely one of their spouses).
    //
    // It is done this way as to not skew the results if any particular parent
    // is unknown or the child is connected to a different spouse.
    ChildrenSimilarity float64

    // Options affects the weights and other aspects of the normalised
    // similarity metrics.
    Options SimilarityOptions
}

// NewSurroundingSimilarity creates a surrounding similarity using default
// similarity options. You can modify or replace the Options after
// instantiation.
func NewSurroundingSimilarity(parentsSimilarity, individualSimilarity, spousesSimilarity, childrenSimilarity float64) *SurroundingSimilarity {
    return &SurroundingSimilarity{
        ParentsSimilarity:    parentsSimilarity,
        IndividualSimilarity: individualSimilarity,
        SpousesSimilarity:    spousesSimilarity,
        ChildrenSimilarity:   childrenSimilarity,
        Options:              NewSimilarityOptions(),
    }
}

// WeightedSimilarity calculates a single similarity from all of the similarity
// metrics with following weights:
//
//   IndividualSimilarity: 80%
//   ParentsSimilarity: ~6.7%
//   SpousesSimilarity: ~6.7%
//   ChildrenSimilarity: ~6.7%
//
func (s SurroundingSimilarity) WeightedSimilarity() float64 {
    individual := s.IndividualSimilarity * s.Options.IndividualWeight
    parents := s.ParentsSimilarity * s.Options.ParentsWeight
    spouses := s.SpousesSimilarity * s.Options.SpousesWeight
    children := s.ChildrenSimilarity * s.Options.ChildrenWeight

    return individual + parents + spouses + children
}

// String returns the WeightedSimilarity -- a number between 0.0 and 1.0.
//
// The WeightedSimilarity is affected by Options.
func (s SurroundingSimilarity) String() string {
    return fmt.Sprintf("%f", s.WeightedSimilarity())
}