Package elki.distance
Class CosineDistance
- java.lang.Object
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- elki.distance.CosineDistance
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- All Implemented Interfaces:
Distance<NumberVector>
,NumberVectorDistance<NumberVector>
,PrimitiveDistance<NumberVector>
,SpatialPrimitiveDistance<NumberVector>
- Direct Known Subclasses:
SqrtCosineDistance
@Priority(100) @Alias("cosine") public class CosineDistance extends java.lang.Object implements SpatialPrimitiveDistance<NumberVector>, NumberVectorDistance<NumberVector>
Cosine distance function for feature vectors.The cosine distance is computed from the cosine similarity by
1-(cosine similarity)
.Cosine similarity is defined as \[ \tfrac{\vec{x}\cdot\vec{y}}{||a||\cdot||b||} \] Cosine distance then is defined as \[ 1 - \tfrac{\vec{x}\cdot\vec{y}}{||a||\cdot||b||} \in [0;2] \]
ArcCosineDistance
orSqrtCosineDistance
can be used if you need a metric, but are more expensive to computate.- Since:
- 0.1
- Author:
- Arthur Zimek
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
CosineDistance.Par
Parameterization class.
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Field Summary
Fields Modifier and Type Field Description static CosineDistance
STATIC
Static instance
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Constructor Summary
Constructors Constructor Description CosineDistance()
Deprecated.Use static instance
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description double
distance(NumberVector v1, NumberVector v2)
Computes the distance between two given DatabaseObjects according to this distance function.boolean
equals(java.lang.Object obj)
SimpleTypeInformation<? super NumberVector>
getInputTypeRestriction()
Get the input data type of the function.int
hashCode()
boolean
isSquared()
Squared distances, that would become metric after square root.double
minDist(SpatialComparable mbr1, SpatialComparable mbr2)
Computes the distance between the two given MBRs according to this distance function.java.lang.String
toString()
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Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
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Methods inherited from interface elki.distance.Distance
isMetric, isSymmetric
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Methods inherited from interface elki.distance.SpatialPrimitiveDistance
instantiate
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Field Detail
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STATIC
public static final CosineDistance STATIC
Static instance
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Constructor Detail
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CosineDistance
@Deprecated public CosineDistance()
Deprecated.Use static instanceConstructor - useSTATIC
instead.
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Method Detail
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distance
public double distance(NumberVector v1, NumberVector v2)
Description copied from interface:PrimitiveDistance
Computes the distance between two given DatabaseObjects according to this distance function.- Specified by:
distance
in interfaceNumberVectorDistance<NumberVector>
- Specified by:
distance
in interfacePrimitiveDistance<NumberVector>
- Parameters:
v1
- first DatabaseObjectv2
- second DatabaseObject- Returns:
- the distance between two given DatabaseObjects according to this distance function
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minDist
public double minDist(SpatialComparable mbr1, SpatialComparable mbr2)
Description copied from interface:SpatialPrimitiveDistance
Computes the distance between the two given MBRs according to this distance function.- Specified by:
minDist
in interfaceSpatialPrimitiveDistance<NumberVector>
- Parameters:
mbr1
- the first MBR objectmbr2
- the second MBR object- Returns:
- the distance between the two given MBRs according to this distance function
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isSquared
public boolean isSquared()
Description copied from interface:Distance
Squared distances, that would become metric after square root.E.g. squared Euclidean.
- Specified by:
isSquared
in interfaceDistance<NumberVector>
- Returns:
true
when squared.
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toString
public java.lang.String toString()
- Overrides:
toString
in classjava.lang.Object
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equals
public boolean equals(java.lang.Object obj)
- Overrides:
equals
in classjava.lang.Object
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hashCode
public int hashCode()
- Overrides:
hashCode
in classjava.lang.Object
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getInputTypeRestriction
public SimpleTypeInformation<? super NumberVector> getInputTypeRestriction()
Description copied from interface:Distance
Get the input data type of the function.- Specified by:
getInputTypeRestriction
in interfaceDistance<NumberVector>
- Specified by:
getInputTypeRestriction
in interfacePrimitiveDistance<NumberVector>
- Returns:
- Type restriction
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