de.javagl.common.collections

Class DoubleMaps

java.lang.Object

de.javagl.common.collections.DoubleMaps

public class DoubleMaps
extends Object

Utility methods related to maps containing Double keys and/or values

Method Summary

Modifier and Type	Method and Description
static <K> Map<K,Double>	create(Collection<? extends K> keys, DoubleUnaryOperator operator) Create a map with the given keys, which are mapped to values that are computed by applying the given operator to the range [0,1], linearly interpolated for the given keys.
static <K> List<Map<K,Double>>	create(Collection<? extends K> keys, List<? extends DoubleUnaryOperator> operators) Create maps with the given keys, which are mapped to values that are computed by applying the given operators to the range [0,1], linearly interpolated for the given keys.
static <K> Map<K,Double>	create(Iterable<? extends K> keys, double min, double max, Random random) Create a map with the given keys, which are mapped to random values in the specified range
static double	getInterpolated(NavigableMap<Double,? extends Number> map, double key) Returns a linearly interpolated value from the given map.
static <K> Map<K,Double>	scaleValuesToRange(Map<K,? extends Number> map, double targetMin, double targetMax) Scale the values in the given map to be in the specified range.
static <K> Map<K,Double>	scaleValuesToRange(Map<K,? extends Number> map, double targetMin, double targetMax, double epsilon, double defaultValue) Scale the values in the given map to be in the specified range.
static <K> Map<K,Double>	transformValues(Map<K,? extends Number> map, DoubleUnaryOperator op) Returns a new map that contains the same keys as the given one, but has its values transformed with the given operator.

Methods inherited from class java.lang.Object

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

Method Detail

create

public static <K> Map<K,Double> create(Iterable<? extends K> keys,
                                       double min,
                                       double max,
                                       Random random)

Create a map with the given keys, which are mapped to random values in the specified range

Type Parameters:

K - The key type

Parameters:

keys - The keys

min - The minimum value

max - The maximum value

random - The random number generator

Returns:

The resulting map

create

public static <K> List<Map<K,Double>> create(Collection<? extends K> keys,
                                             List<? extends DoubleUnaryOperator> operators)

Create maps with the given keys, which are mapped to values that are computed by applying the given operators to the range [0,1], linearly interpolated for the given keys.

Type Parameters:

K - The key type

Parameters:

keys - The keys

operators - The operators

Returns:

The resulting maps

create

public static <K> Map<K,Double> create(Collection<? extends K> keys,
                                       DoubleUnaryOperator operator)

Create a map with the given keys, which are mapped to values that are computed by applying the given operator to the range [0,1], linearly interpolated for the given keys.

Type Parameters:

K - The key type

Parameters:

keys - The keys

operator - The operator

Returns:

The resulting map

scaleValuesToRange

public static <K> Map<K,Double> scaleValuesToRange(Map<K,? extends Number> map,
                                                   double targetMin,
                                                   double targetMax)

Scale the values in the given map to be in the specified range. The minimum value of the given map will be mapped to the given target minimum, and the maximum value to the target maximum. If the range of the values in the given map is not greater than a small epsilon, then the minimum target value will be used.

Type Parameters:

K - The key type

Parameters:

map - The map

targetMin - The target minimum

targetMax - The target maximum

Returns:

The resulting map

scaleValuesToRange

public static <K> Map<K,Double> scaleValuesToRange(Map<K,? extends Number> map,
                                                   double targetMin,
                                                   double targetMax,
                                                   double epsilon,
                                                   double defaultValue)

Scale the values in the given map to be in the specified range. The minimum value of the given map will be mapped to the given target minimum, and the maximum value to the target maximum. If the range of the values in the given map is not greater than the given epsilon, then the given default value will be used.

Type Parameters:

K - The key type

Parameters:

map - The map

targetMin - The target minimum

targetMax - The target maximum

epsilon - The epsilon

defaultValue - The default value

Returns:

The resulting map

transformValues

public static <K> Map<K,Double> transformValues(Map<K,? extends Number> map,
                                                DoubleUnaryOperator op)

Returns a new map that contains the same keys as the given one, but has its values transformed with the given operator. If any value of the input is null, then the value in the result will also be null.

Type Parameters:

K - The key type

Parameters:

map - The map

op - The operator

Returns:

The result

getInterpolated

public static double getInterpolated(NavigableMap<Double,? extends Number> map,
                                     double key)

Returns a linearly interpolated value from the given map.

For the given key, the next larger and next smaller key will be determined. The values associated with these keys will be interpolated, based on the location of the given key between the next larger and smaller key.

If the given key is larger than the largest key in the given map, then the value of the largest key will be returned.

If the given key is smaller than the smallest key in the given map, then the value of the smallest key will be returned.

Parameters:

map - The map

key - The key

Returns:

The interpolated value

Throws:

IllegalArgumentException - If the given map is empty