Class Statistics

java.lang.Object
org.apache.commons.statistics.descriptive.Statistics
final class Statistics extends Object
Utility methods for statistics.
Since:
1.1

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    (package private) static final DoubleConsumer
    DOUBLE_NOOP
    A no-operation double consumer.
    private static final String
    INCOMPATIBLE_STATISTICS
    Error message for an incompatible statistics.
    (package private) static final IntConsumer
    INT_NOOP
    A no-operation int consumer.
    (package private) static final LongConsumer
    LONG_NOOP
    A no-operation long consumer.

  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
    private
    Statistics()
    No instances.

  • Method Summary

    Modifier and Type
    Method
    Description
    (package private) static <T extends DoubleConsumer>
    T
    add(T statistic, double[] values)
    Add all the values to the statistic.
    (package private) static <T extends DoubleConsumer>
    T
    add(T statistic, double[] values, int from, int to)
    Add the specified range of values to the statistic.
    (package private) static <T extends DoubleConsumer>
    T
    add(T statistic, int[] values)
    Add all the values to the statistic.
    (package private) static <T extends IntConsumer>
    T
    add(T statistic, int[] values)
    Add all the values to the statistic.
    (package private) static <T extends DoubleConsumer>
    T
    add(T statistic, int[] values, int from, int to)
    Add the specified range of values to the statistic.
    (package private) static <T extends IntConsumer>
    T
    add(T statistic, int[] values, int from, int to)
    Add the specified range of values to the statistic.
    (package private) static <T extends DoubleConsumer>
    T
    add(T statistic, long[] values)
    Add all the values to the statistic.
    (package private) static <T extends LongConsumer>
    T
    add(T statistic, long[] values)
    Add all the values to the statistic.
    (package private) static <T extends DoubleConsumer>
    T
    add(T statistic, long[] values, int from, int to)
    Add the specified range of values to the statistic.
    (package private) static <T extends LongConsumer>
    T
    add(T statistic, long[] values, int from, int to)
    Add the specified range of values to the statistic.
    (package private) static void
    checkCombineAssignable(FirstMoment a, FirstMoment b)
    Check left-hand side argument a is null or else the right-hand side argument b must be run-time assignable to the same class as a so the statistics can be combined.
    (package private) static <T extends StatisticResult & StatisticAccumulator<T>>
    void
    checkCombineCompatible(T a, T b)
    Check left-hand side argument a is null or else the right-hand side argument b must also be non-null so the statistics can be combined.
    (package private) static void
    checkFromToIndex(int fromIndex, int toIndex, int length)
    Checks if the sub-range from fromIndex (inclusive) to toIndex (exclusive) is within the bounds of range from 0 (inclusive) to length (exclusive).
    (package private) static <T extends StatisticResult & StatisticAccumulator<T>>
    void
    combine(T a, T b)
    If the left-hand side argument a is non-null, combine it with the right-hand side argument b.
    (package private) static void
    combineMoment(FirstMoment a, FirstMoment b)
    If the left-hand side argument a is non-null, combine it with the right-hand side argument b.
    (package private) static DoubleConsumer
    composeDoubleConsumers(DoubleConsumer... consumers)
    Chain the consumers into a single composite consumer.
    (package private) static IntConsumer
    composeIntConsumers(IntConsumer... consumers)
    Chain the consumers into a single composite consumer.
    (package private) static LongConsumer
    composeLongConsumers(LongConsumer... consumers)
    Chain the consumers into a single composite consumer.
    (package private) static int[]
    copy(int[] data, int from, int to)
    Copy the specified range of data.
    (package private) static StatisticResult
    getResultAsBigIntegerOrNull(StatisticResult s)
    Gets the statistic result using the BigInteger value.
    (package private) static StatisticResult
    getResultAsDoubleOrNull(StatisticResult s)
    Gets the statistic result using the double value.
    (package private) static StatisticResult
    getResultAsIntOrNull(StatisticResult s)
    Gets the statistic result using the int value.
    (package private) static StatisticResult
    getResultAsLongOrNull(StatisticResult s)
    Gets the statistic result using the long value.
    private static String
    msgRangeOutOfBounds(int fromIndex, int toIndex, int length)
    Format a message when range [from, to) is not entirely within the length.
    (package private) static org.apache.commons.numbers.core.Sum
    sum(double[] values, int from, int to)
    Sum the specified range of values.
    (package private) static boolean
    zeroVariance(double m1, double m2)
    Returns true if the second central moment m2 is effectively zero given the magnitude of the first raw moment m1.

    Methods inherited from class Object

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

  • Field Details

    • DOUBLE_NOOP

      static final DoubleConsumer DOUBLE_NOOP
      A no-operation double consumer. This is exposed for testing.

    • INT_NOOP

      static final IntConsumer INT_NOOP
      A no-operation int consumer. This is exposed for testing.

    • LONG_NOOP

      static final LongConsumer LONG_NOOP
      A no-operation long consumer. This is exposed for testing.

    • INCOMPATIBLE_STATISTICS

      private static final String INCOMPATIBLE_STATISTICS
      Error message for an incompatible statistics.
      See Also:

  • Constructor Details

    • Statistics

      private Statistics()
      No instances.

  • Method Details

    • add

      static <T extends DoubleConsumer> T add(T statistic, double[] values)
      Add all the values to the statistic.
      Type Parameters:
      T - Type of the statistic
      Parameters:
      statistic - Statistic.
      values - Values.
      Returns:
      the statistic

    • add

      static <T extends DoubleConsumer> T add(T statistic, double[] values, int from, int to)
      Add the specified range of values to the statistic.

      Warning: No range checks are performed.

      Type Parameters:
      T - Type of the statistic
      Parameters:
      statistic - Statistic.
      values - Values.
      from - Inclusive start of the range.
      to - Exclusive end of the range.
      Returns:
      the statistic

    • add

      static <T extends DoubleConsumer> T add(T statistic, int[] values)
      Add all the values to the statistic.
      Type Parameters:
      T - Type of the statistic
      Parameters:
      statistic - Statistic.
      values - Values.
      Returns:
      the statistic

    • add

      static <T extends DoubleConsumer> T add(T statistic, int[] values, int from, int to)
      Add the specified range of values to the statistic.

      Warning: No range checks are performed.

      Type Parameters:
      T - Type of the statistic
      Parameters:
      statistic - Statistic.
      values - Values.
      from - Inclusive start of the range.
      to - Exclusive end of the range.
      Returns:
      the statistic

    • add

      static <T extends DoubleConsumer> T add(T statistic, long[] values)
      Add all the values to the statistic.
      Type Parameters:
      T - Type of the statistic
      Parameters:
      statistic - Statistic.
      values - Values.
      Returns:
      the statistic

    • add

      static <T extends DoubleConsumer> T add(T statistic, long[] values, int from, int to)
      Add the specified range of values to the statistic.

      Warning: No range checks are performed.

      Type Parameters:
      T - Type of the statistic
      Parameters:
      statistic - Statistic.
      values - Values.
      from - Inclusive start of the range.
      to - Exclusive end of the range.
      Returns:
      the statistic

    • add

      static <T extends IntConsumer> T add(T statistic, int[] values)
      Add all the values to the statistic.
      Type Parameters:
      T - Type of the statistic
      Parameters:
      statistic - Statistic.
      values - Values.
      Returns:
      the statistic

    • add

      static <T extends IntConsumer> T add(T statistic, int[] values, int from, int to)
      Add the specified range of values to the statistic.

      Warning: No range checks are performed.

      Type Parameters:
      T - Type of the statistic
      Parameters:
      statistic - Statistic.
      values - Values.
      from - Inclusive start of the range.
      to - Exclusive end of the range.
      Returns:
      the statistic

    • add

      static <T extends LongConsumer> T add(T statistic, long[] values)
      Add all the values to the statistic.
      Type Parameters:
      T - Type of the statistic
      Parameters:
      statistic - Statistic.
      values - Values.
      Returns:
      the statistic

    • add

      static <T extends LongConsumer> T add(T statistic, long[] values, int from, int to)
      Add the specified range of values to the statistic.

      Warning: No range checks are performed.

      Type Parameters:
      T - Type of the statistic
      Parameters:
      statistic - Statistic.
      values - Values.
      from - Inclusive start of the range.
      to - Exclusive end of the range.
      Returns:
      the statistic

    • zeroVariance

      static boolean zeroVariance(double m1, double m2)
      Returns true if the second central moment m2 is effectively zero given the magnitude of the first raw moment m1.

      This method shares the logic for detecting a zero variance among implementations that divide by the variance (e.g. skewness, kurtosis).

      Parameters:
      m1 - First raw moment (mean).
      m2 - Second central moment (biased variance).
      Returns:
      true if the variance is zero

    • composeDoubleConsumers

      static DoubleConsumer composeDoubleConsumers(DoubleConsumer... consumers)
      Chain the consumers into a single composite consumer. Ignore any null consumer. Returns null if all arguments are null.
      Parameters:
      consumers - Consumers.
      Returns:
      a composed consumer (or null)

    • composeIntConsumers

      static IntConsumer composeIntConsumers(IntConsumer... consumers)
      Chain the consumers into a single composite consumer. Ignore any null consumer. Returns null if all arguments are null.
      Parameters:
      consumers - Consumers.
      Returns:
      a composed consumer (or null)

    • composeLongConsumers

      static LongConsumer composeLongConsumers(LongConsumer... consumers)
      Chain the consumers into a single composite consumer. Ignore any null consumer. Returns null if all arguments are null.
      Parameters:
      consumers - Consumers.
      Returns:
      a composed consumer (or null)

    • getResultAsIntOrNull

      static StatisticResult getResultAsIntOrNull(StatisticResult s)
      Gets the statistic result using the int value. Return null is the statistic is null.
      Parameters:
      s - Statistic.
      Returns:
      the result or null

    • getResultAsLongOrNull

      static StatisticResult getResultAsLongOrNull(StatisticResult s)
      Gets the statistic result using the long value. Return null is the statistic is null.
      Parameters:
      s - Statistic.
      Returns:
      the result or null

    • getResultAsDoubleOrNull

      static StatisticResult getResultAsDoubleOrNull(StatisticResult s)
      Gets the statistic result using the double value. Return null is the statistic is null.
      Parameters:
      s - Statistic.
      Returns:
      the result or null

    • getResultAsBigIntegerOrNull

      static StatisticResult getResultAsBigIntegerOrNull(StatisticResult s)
      Gets the statistic result using the BigInteger value. Return null is the statistic is null.
      Parameters:
      s - Statistic.
      Returns:
      the result or null

    • checkCombineCompatible

      static <T extends StatisticResult & StatisticAccumulator<T>> void checkCombineCompatible(T a, T b)
      Check left-hand side argument a is null or else the right-hand side argument b must also be non-null so the statistics can be combined.
      Type Parameters:
      T - StatisticResult being accumulated.
      Parameters:
      a - LHS.
      b - RHS.
      Throws:
      IllegalArgumentException - if the objects cannot be combined

    • checkCombineAssignable

      static void checkCombineAssignable(FirstMoment a, FirstMoment b)
      Check left-hand side argument a is null or else the right-hand side argument b must be run-time assignable to the same class as a so the statistics can be combined.
      Parameters:
      a - LHS.
      b - RHS.
      Throws:
      IllegalArgumentException - if the objects cannot be combined

    • combine

      static <T extends StatisticResult & StatisticAccumulator<T>> void combine(T a, T b)
      If the left-hand side argument a is non-null, combine it with the right-hand side argument b.
      Type Parameters:
      T - StatisticResult being accumulated.
      Parameters:
      a - LHS.
      b - RHS.

    • combineMoment

      static void combineMoment(FirstMoment a, FirstMoment b)
      If the left-hand side argument a is non-null, combine it with the right-hand side argument b. Assumes that the RHS is run-time assignable to the same class as LHS.
      Parameters:
      a - LHS.
      b - RHS.
      See Also:

    • checkFromToIndex

      static void checkFromToIndex(int fromIndex, int toIndex, int length)
      Checks if the sub-range from fromIndex (inclusive) to toIndex (exclusive) is within the bounds of range from 0 (inclusive) to length (exclusive).

      This function provides the functionality of java.utils.Objects.checkFromToIndex introduced in JDK 9. The Objects javadoc has been reproduced for reference. The return value has been changed to void.

      The sub-range is defined to be out of bounds if any of the following inequalities is true:

      • fromIndex < 0
      • fromIndex > toIndex
      • toIndex > length
      • length < 0, which is implied from the former inequalities
      Parameters:
      fromIndex - Lower-bound (inclusive) of the sub-range.
      toIndex - Upper-bound (exclusive) of the sub-range.
      length - Upper-bound (exclusive) of the range.
      Throws:
      IndexOutOfBoundsException - if the sub-range is out of bounds

    • msgRangeOutOfBounds

      private static String msgRangeOutOfBounds(int fromIndex, int toIndex, int length)
      Format a message when range [from, to) is not entirely within the length.
      Parameters:
      fromIndex - Lower-bound (inclusive) of the sub-range.
      toIndex - Upper-bound (exclusive) of the sub-range.
      length - Upper-bound (exclusive) of the range.
      Returns:
      the message

    • sum

      static org.apache.commons.numbers.core.Sum sum(double[] values, int from, int to)
      Sum the specified range of values.

      Warning: No range checks are performed.

      Parameters:
      values - Values.
      from - Inclusive start of the range.
      to - Exclusive end of the range.
      Returns:
      the sum

    • copy

      static int[] copy(int[] data, int from, int to)
      Copy the specified range of data.

      This is a simplification of

      invalid reference 
      Arrays#copyOfRange(double[], int, int)
      and does not support range checks or padding of the original input to a longer output.
      Parameters:
      data - Values.
      from - Inclusive start of the range.
      to - Exclusive end of the range.
      Returns:
      the copy