Package org.onebusaway.utility

Class InterpolationLibrary

java.lang.Object

org.onebusaway.utility.InterpolationLibrary

public class InterpolationLibrary
extends Object

Generic methods to support interpolation of values against a sorted key-value map given a new target key. Note that these interpolation methods do not conform to the GTFS-rt spec. For GTFS-rt compliant interpolation/extrapolation, see TransitInterpolationLibrary.

Author:

bdferris

Constructor Summary

Constructors

Constructor	Description
InterpolationLibrary()

Method Summary

Modifier and Type	Method	Description
static double	interpolate(double[] keys, double[] values, double target, EOutOfRangeStrategy outOfRangeStrategy)
static double	interpolate(double[] keys, double[] values, double target, EOutOfRangeStrategy outOfRangeStrategy, EInRangeStrategy inRangeStrategy)
static <K extends Number,V extends Number> double	interpolate(SortedMap<K,V> values, K target)	Same behavior as interpolate(SortedMap, Number, EOutOfRangeStrategy) but with a default EOutOfRangeStrategy of EOutOfRangeStrategy.INTERPOLATE.
static <K extends Number,V extends Number> double	interpolate(SortedMap<K,V> values, K target, EOutOfRangeStrategy outOfRangeStrategy)	Given a SortedMap with key-values that all extend from Number, interpolate using linear interpolation a value for a target key within the key-range of the map.
static <KEY extends Number,VALUE,ANY_KEY extends KEY,ANY_VALUE extends VALUE> VALUE	interpolate(InterpolationStrategy<KEY,VALUE> interpolationStrategy, EOutOfRangeStrategy outOfRangeStrategy, SortedMap<ANY_KEY,ANY_VALUE> values, ANY_KEY target)	Given a SortedMap with key-values that of arbitrary type and a InterpolationStrategy to define interpolation over those types, interpolate a value for a target key within the key-range of the map.
static double	interpolatePair(double fromValue, double toValue, double ratio)	Simple numeric interpolation between two double values using the equation ratio * (toValue - fromValue) + fromValue
static double	interpolatePair(double keyA, double valueA, double keyB, double valueB, double targetKey)	Simple numeric interpolation between two pairs of key-values and a third key.
static <K extends Number,V> V	nearestNeighbor(SortedMap<K,V> values, K target)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

InterpolationLibrary

public InterpolationLibrary()

Method Detail

interpolate

public static <K extends Number,V extends Number> double interpolate(SortedMap<K,V> values,
                                                                           K target)

Same behavior as interpolate(SortedMap, Number, EOutOfRangeStrategy) but with a default EOutOfRangeStrategy of EOutOfRangeStrategy.INTERPOLATE.

Parameters:

values - a sorted-map of key-value number pairs

target - the target key used to interpolate a value

outOfRangeStrategy - the strategy to use for a target key that outside the key-range of the value map

Returns:

an interpolated value for the target key

interpolate

public static <K extends Number,V extends Number> double interpolate(SortedMap<K,V> values,
                                                                           K target,
                                                                           EOutOfRangeStrategy outOfRangeStrategy)

Given a SortedMap with key-values that all extend from Number, interpolate using linear interpolation a value for a target key within the key-range of the map. For a key outside the range of the keys of the map, the outOfRange EOutOfRangeStrategy strategy will determine the interpolation behavior.

Parameters:

values - a sorted-map of key-value number pairs

target - the target key used to interpolate a value

outOfRangeStrategy - the strategy to use for a target key that outside the key-range of the value map

Returns:

an interpolated value for the target key

nearestNeighbor

public static <K extends Number,V> V nearestNeighbor(SortedMap<K,V> values,
                                                           K target)

interpolate

public static double interpolate(double[] keys,
                                 double[] values,
                                 double target,
                                 EOutOfRangeStrategy outOfRangeStrategy)

interpolate

public static double interpolate(double[] keys,
                                 double[] values,
                                 double target,
                                 EOutOfRangeStrategy outOfRangeStrategy,
                                 EInRangeStrategy inRangeStrategy)

interpolatePair

public static double interpolatePair(double fromValue,
                                     double toValue,
                                     double ratio)

Simple numeric interpolation between two double values using the equation ratio * (toValue - fromValue) + fromValue

Parameters:

fromValue -

toValue -

ratio -

Returns:

ratio * (toValue - fromValue) + fromValue

interpolatePair

public static double interpolatePair(double keyA,
                                     double valueA,
                                     double keyB,
                                     double valueB,
                                     double targetKey)

Simple numeric interpolation between two pairs of key-values and a third key. Here, ratio = (targetKey - keyA) / (keyB - keyA) and the result is ratio * (valueB - valueA) + valueA.

Parameters:

fromValue -

toValue -

ratio -

Returns:

ratio * (toValue - fromValue) + fromValue

interpolate

public static <KEY extends Number,VALUE,ANY_KEY extends KEY,ANY_VALUE extends VALUE> VALUE interpolate(InterpolationStrategy<KEY,VALUE> interpolationStrategy,
                                                                                                                         EOutOfRangeStrategy outOfRangeStrategy,
                                                                                                                         SortedMap<ANY_KEY,ANY_VALUE> values,
                                                                                                                         ANY_KEY target)

Given a SortedMap with key-values that of arbitrary type and a InterpolationStrategy to define interpolation over those types, interpolate a value for a target key within the key-range of the map. For a key outside the range of the keys of the map, the outOfRange EOutOfRangeStrategy strategy will determine the interpolation behavior.

Parameters:

interpolationStrategy - the interpolation strategy used to perform interpolation between key-value pairs of arbitrary type

outOfRangeStrategy - the strategy to use for a target key that outside the key-range of the value map

values - a sorted-map of key-value pairs

target - the target key used to interpolate a value

Returns:

an interpolated value for the target key