diff options
Diffstat (limited to 'core')
3 files changed, 45 insertions, 28 deletions
diff --git a/core/source/core/scala/org/hashtree/stringmetric/StringMetric.scala b/core/source/core/scala/org/hashtree/stringmetric/StringMetric.scala index 9cabb82..078361b 100755 --- a/core/source/core/scala/org/hashtree/stringmetric/StringMetric.scala +++ b/core/source/core/scala/org/hashtree/stringmetric/StringMetric.scala @@ -10,11 +10,11 @@ trait StringMetric extends Metric[String] { /** Convenience object for those extending [[org.hashtree.stringmetric.StringMetric]]. */ object StringMetric { - def compareDiceSorensen(charArray1: Array[Char], charArray2: Array[Char])(implicit stringFilter: StringFilter): Option[Double] = - DiceSorensenMetric.compare(charArray1, charArray2)(stringFilter) + def compareDiceSorensen(charArray1: Array[Char], charArray2: Array[Char])(n: Int)(implicit stringFilter: StringFilter): Option[Double] = + DiceSorensenMetric.compare(charArray1, charArray2)(n)(stringFilter) - def compareDiceSorensen(string1: String, string2: String)(implicit stringFilter: StringFilter): Option[Double] = - DiceSorensenMetric.compare(string1, string2)(stringFilter) + def compareDiceSorensen(string1: String, string2: String)(n: Int)(implicit stringFilter: StringFilter): Option[Double] = + DiceSorensenMetric.compare(string1, string2)(n)(stringFilter) def compareHamming(charArray1: Array[Char], charArray2: Array[Char])(implicit stringFilter: StringFilter): Option[Int] = HammingMetric.compare(charArray1, charArray2)(stringFilter) diff --git a/core/source/core/scala/org/hashtree/stringmetric/similarity/DiceSorensenMetric.scala b/core/source/core/scala/org/hashtree/stringmetric/similarity/DiceSorensenMetric.scala index cc13fa3..d77c8e7 100755 --- a/core/source/core/scala/org/hashtree/stringmetric/similarity/DiceSorensenMetric.scala +++ b/core/source/core/scala/org/hashtree/stringmetric/similarity/DiceSorensenMetric.scala @@ -1,30 +1,33 @@ package org.hashtree.stringmetric.similarity -import org.hashtree.stringmetric.{ FilterableStringMetric, MatchTuple, StringFilter, StringMetric, StringFilterDelegate } +import org.hashtree.stringmetric.{ FilterableConfigurableStringMetric, MatchTuple, StringFilter, StringMetric, StringFilterDelegate } -/** An implementation of the Dice, and Sorensen, [[org.hashtree.stringmetric.StringMetric]]. */ -object DiceSorensenMetric extends StringMetric with FilterableStringMetric { - override def compare(charArray1: Array[Char], charArray2: Array[Char])(implicit stringFilter: StringFilter): Option[Double] = { +/** + * An implementation of the Dice, and lesser known Sorensen, [[org.hashtree.stringmetric.StringMetric]]. This + * implementation differs in that n-gram size is required. Traditionally, the algorithm uses bigrams. + */ +object DiceSorensenMetric extends StringMetric with FilterableConfigurableStringMetric[Int] { + override def compare(charArray1: Array[Char], charArray2: Array[Char])(n: Int)(implicit stringFilter: StringFilter): Option[Double] = { val ca1 = stringFilter.filter(charArray1) val ca2 = stringFilter.filter(charArray2) if (ca1.length == 0 || ca2.length == 0) None - else if (ca1.length < 2 || ca2.length < 2) Some(0d) // Because length is less than that of bigram, it will always be 0. + else if (ca1.length < n || ca2.length < n) Some(0d) // Because length is less than n, it will always be 0. else if (ca1.sameElements(ca2)) Some(1d) else { - val ca1bg = NGramAlgorithm.compute(ca1)(2).get - val ca2bg = NGramAlgorithm.compute(ca2)(2).get + val ca1bg = NGramAlgorithm.compute(ca1)(n).get + val ca2bg = NGramAlgorithm.compute(ca2)(n).get val ms = scoreMatches((ca1bg.map(_.mkString), ca2bg.map(_.mkString))) Some((2d * ms) / (ca1bg.length + ca2bg.length)) } } - override def compare(string1: String, string2: String)(implicit stringFilter: StringFilter): Option[Double] = + override def compare(string1: String, string2: String)(n: Int)(implicit stringFilter: StringFilter): Option[Double] = compare( stringFilter.filter(string1.toCharArray), stringFilter.filter(string2.toCharArray) - )(new StringFilterDelegate) + )(n: Int)(new StringFilterDelegate) private[this] def scoreMatches(mt: MatchTuple[String]) = mt._1.intersect(mt._2).length }
\ No newline at end of file diff --git a/core/source/test/scala/org/hashtree/stringmetric/similarity/DiceSorensenMetricSpec.scala b/core/source/test/scala/org/hashtree/stringmetric/similarity/DiceSorensenMetricSpec.scala index 0e8b3a7..163bab5 100755 --- a/core/source/test/scala/org/hashtree/stringmetric/similarity/DiceSorensenMetricSpec.scala +++ b/core/source/test/scala/org/hashtree/stringmetric/similarity/DiceSorensenMetricSpec.scala @@ -10,37 +10,51 @@ final class DiceSorensenMetricSpec extends ScalaTest { "compare method" when passed { "empty arguments" should returns { "None" in { - DiceSorensenMetric.compare("", "").isDefined should be (false) - DiceSorensenMetric.compare("abc", "").isDefined should be (false) - DiceSorensenMetric.compare("", "xyz").isDefined should be (false) + DiceSorensenMetric.compare("", "")(1).isDefined should be (false) + DiceSorensenMetric.compare("abc", "")(1).isDefined should be (false) + DiceSorensenMetric.compare("", "xyz")(1).isDefined should be (false) } } "equal arguments" should returns { "1" in { - DiceSorensenMetric.compare("abc", "abc").get should be (1) + DiceSorensenMetric.compare("abc", "abc")(1).get should be (1) + DiceSorensenMetric.compare("abc", "abc")(2).get should be (1) + DiceSorensenMetric.compare("abc", "abc")(3).get should be (1) } } "unequal arguments" should returns { "0" in { - DiceSorensenMetric.compare("abc", "xyz").get should be (0) + DiceSorensenMetric.compare("abc", "xyz")(1).get should be (0) + DiceSorensenMetric.compare("abc", "xyz")(2).get should be (0) + DiceSorensenMetric.compare("abc", "xyz")(3).get should be (0) } } "invalid arguments" should returns { "Double indicating distance" in { - DiceSorensenMetric.compare("n", "naght").get should be (0) - DiceSorensenMetric.compare("night", "n").get should be (0) + DiceSorensenMetric.compare("n", "naght")(2).get should be (0) + DiceSorensenMetric.compare("night", "n")(2).get should be (0) + DiceSorensenMetric.compare("ni", "naght")(3).get should be (0) + DiceSorensenMetric.compare("night", "na")(3).get should be (0) } } "valid arguments" should returns { "Double indicating distance" in { - DiceSorensenMetric.compare("night", "nacht").get should be (0.25) - DiceSorensenMetric.compare("night", "naght").get should be (0.5) - DiceSorensenMetric.compare("context", "contact").get should be (0.5) - DiceSorensenMetric.compare("contextcontext", "contact").get should be (0.3157894736842105) - DiceSorensenMetric.compare("context", "contactcontact").get should be (0.3157894736842105) - DiceSorensenMetric.compare("ht", "nacht").get should be (0.4) - DiceSorensenMetric.compare("xp", "nacht").get should be (0) - DiceSorensenMetric.compare("ht", "hththt").get should be (0.3333333333333333) + DiceSorensenMetric.compare("night", "nacht")(1).get should be (0.6) + DiceSorensenMetric.compare("night", "naght")(1).get should be (0.8) + DiceSorensenMetric.compare("context", "contact")(1).get should be (0.7142857142857143) + + DiceSorensenMetric.compare("night", "nacht")(2).get should be (0.25) + DiceSorensenMetric.compare("night", "naght")(2).get should be (0.5) + DiceSorensenMetric.compare("context", "contact")(2).get should be (0.5) + DiceSorensenMetric.compare("contextcontext", "contact")(2).get should be (0.3157894736842105) + DiceSorensenMetric.compare("context", "contactcontact")(2).get should be (0.3157894736842105) + DiceSorensenMetric.compare("ht", "nacht")(2).get should be (0.4) + DiceSorensenMetric.compare("xp", "nacht")(2).get should be (0) + DiceSorensenMetric.compare("ht", "hththt")(2).get should be (0.3333333333333333) + + DiceSorensenMetric.compare("night", "nacht")(3).get should be (0) + DiceSorensenMetric.compare("night", "naght")(3).get should be (0.3333333333333333) + DiceSorensenMetric.compare("context", "contact")(3).get should be (0.4) } } } |