net.volcanite.util

Class DoubleStatisticsNoSync

java.lang.Object

net.volcanite.util.DoubleStatisticsNoSync

All Implemented Interfaces:

DoubleStatistics

public class DoubleStatisticsNoSync
extends Object
implements DoubleStatistics

A state object for collecting statistics such as count, min, max, sum, average and variance (or standard deviation).

Constructor Summary

Constructors

Constructor and Description
DoubleStatisticsNoSync() Construct an empty instance with zero count, zero sum, Double.POSITIVE_INFINITY min, Double.NEGATIVE_INFINITY max and zero average.
DoubleStatisticsNoSync(DoubleStatisticsNoSync other) Constructs a non-empty instance with an initial state that corresponds to the current state of the specified other DoubleStatisticsNoSync instance.

Method Summary

Modifier and Type	Method and Description
void	accept(double value) Records another value into the summary information.
double	getAverage() Returns the arithmetic mean of values recorded, or zero if no values have been recorded.
long	getCount() Return the count of values recorded.
double	getMax() Returns the maximum recorded value, Double.NaN if any recorded value was NaN or Double.NEGATIVE_INFINITY if no values were recorded.
double	getMin() Returns the minimum recorded value, Double.NaN if any recorded value was NaN or Double.POSITIVE_INFINITY if no values were recorded.
double	getStandardDeviation()
double	getSum() Returns the sum of values recorded, or zero if no values have been recorded.
double	getVariance()
String	toString() Returns a non-empty string representation of this object suitable for debugging.

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.volcanite.util.DoubleStatistics

newInstance, newInstance

Constructor Detail

DoubleStatisticsNoSync

public DoubleStatisticsNoSync()

Construct an empty instance with zero count, zero sum, Double.POSITIVE_INFINITY min, Double.NEGATIVE_INFINITY max and zero average.

DoubleStatisticsNoSync

public DoubleStatisticsNoSync(DoubleStatisticsNoSync other)
                       throws IllegalArgumentException

Constructs a non-empty instance with an initial state that corresponds to the current state of the specified other DoubleStatisticsNoSync instance.

If other.count is zero then the remaining arguments are ignored and an empty instance is constructed.

If the state of other is inconsistent then an IllegalArgumentException is thrown. The necessary conditions for a consistent state are:

• other.count >= 0
• (other.min <= other.max && !isNaN(other.sum)) || (isNaN(other.min) && isNaN(other.max) && isNaN(other.sum))

API Note:
The enforcement of state correctness means that the retrieved set of recorded values obtained from a DoubleStatisticsNoSync source instance may not be a legal state for this constructor due to arithmetic overflow of the source's recorded count of values. The consistency conditions are not sufficient to prevent the creation of an internally inconsistent instance. An example of such a state would be an instance with: other.count = 2, other.min = 1, other.max = 2, and other.sum = 0.

Parameters:

other - the DoubleStatisticsNoSync instance whose state should be replicated

Throws:

NullPointerException - if other is null

IllegalArgumentException - if the internal state of the other object is inconsistent

Method Detail

accept

public void accept(double value)

Records another value into the summary information.

Specified by:

accept in interface DoubleStatistics

Parameters:

value - the input value

getCount

public final long getCount()

Return the count of values recorded.

Specified by:

getCount in interface DoubleStatistics

Returns:

the count of values

getSum

public final double getSum()

Returns the sum of values recorded, or zero if no values have been recorded.

The value of a floating-point sum is a function both of the input values as well as the order of addition operations. The order of addition operations of this method is intentionally not defined to allow for implementation flexibility to improve the speed and accuracy of the computed result. In particular, this method may be implemented using compensated summation or other technique to reduce the error bound in the numerical sum compared to a simple summation of double values. Because of the unspecified order of operations and the possibility of using differing summation schemes, the output of this method may vary on the same input values.

Various conditions can result in a non-finite sum being computed. This can occur even if the all the recorded values being summed are finite. If any recorded value is non-finite, the sum will be non-finite:

• If any recorded value is a NaN, then the final sum will be NaN.
• If the recorded values contain one or more infinities, the sum will be infinite or NaN.
  • If the recorded values contain infinities of opposite sign, the sum will be NaN.
  • If the recorded values contain infinities of one sign and an intermediate sum overflows to an infinity of the opposite sign, the sum may be NaN.

It is possible for intermediate sums of finite values to overflow into opposite-signed infinities; if that occurs, the final sum will be NaN even if the recorded values are all finite. If all the recorded values are zero, the sign of zero is not guaranteed to be preserved in the final sum.

API Note:
Values sorted by increasing absolute magnitude tend to yield more accurate results.

Specified by:

getSum in interface DoubleStatistics

Returns:

the sum of values, or zero if none

getMin

public final double getMin()

Returns the minimum recorded value, Double.NaN if any recorded value was NaN or Double.POSITIVE_INFINITY if no values were recorded. Unlike the numerical comparison operators, this method considers negative zero to be strictly smaller than positive zero.

Specified by:

getMin in interface DoubleStatistics

Returns:

the minimum recorded value, Double.NaN if any recorded value was NaN or Double.POSITIVE_INFINITY if no values were recorded

getMax

public final double getMax()

Returns the maximum recorded value, Double.NaN if any recorded value was NaN or Double.NEGATIVE_INFINITY if no values were recorded. Unlike the numerical comparison operators, this method considers negative zero to be strictly smaller than positive zero.

Specified by:

getMax in interface DoubleStatistics

Returns:

the maximum recorded value, Double.NaN if any recorded value was NaN or Double.NEGATIVE_INFINITY if no values were recorded

getAverage

public final double getAverage()

Returns the arithmetic mean of values recorded, or zero if no values have been recorded.

The computed average can vary numerically and have the special case behavior as computing the sum; see DoubleStatistics.getSum() for details.

API Note:
Values sorted by increasing absolute magnitude tend to yield more accurate results.

Specified by:

getAverage in interface DoubleStatistics

Returns:

the arithmetic mean of values, or zero if none

getVariance

public final double getVariance()

Specified by:

getVariance in interface DoubleStatistics

getStandardDeviation

public final double getStandardDeviation()

Specified by:

getStandardDeviation in interface DoubleStatistics

toString

public String toString()

Returns a non-empty string representation of this object suitable for debugging. The exact presentation format is unspecified and may vary between implementations and versions.

Specified by:

toString in interface DoubleStatistics

Overrides:

toString in class Object

Returns:

a string representation of this object