math.probe

Interface DoubleStatistics

All Known Implementing Classes:

DoubleStatisticsNoSync, DoubleStatisticsSync

public interface DoubleStatistics

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

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()
static DoubleStatistics	newInstance() Creates a new non-threadsafe DoubleStatistics instance.
static DoubleStatistics	newInstance(boolean threadsafe) Creates a new DoubleStatistics instance which, depending on the threadsafe argument, is either threadsafe or non-threadsafe.
String	toString() Returns a non-empty string representation of this object suitable for debugging.

Method Detail

newInstance

static DoubleStatistics newInstance()

Creates a new non-threadsafe DoubleStatistics instance.

Returns:

a new non-threadsafe DoubleStatistics instance

newInstance

static DoubleStatistics newInstance(boolean threadsafe)

Creates a new DoubleStatistics instance which, depending on the threadsafe argument, is either threadsafe or non-threadsafe.

Parameters:

threadsafe - if true a threadsafe DoubleStatistics gets created

Returns:

a new DoubleStatistics instance which is either threadsafe or non-threadsafe (depending on the value of the threadsafe argument)

accept

void accept(double value)

Records another value into the summary information.

Parameters:

value - the input value

getCount

long getCount()

Return the count of values recorded.

Returns:

the count of values

getSum

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.

Returns:

the sum of values, or zero if none

getMin

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.

Returns:

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

getMax

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.

Returns:

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

getAverage

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 getSum() for details.

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

Returns:

the arithmetic mean of values, or zero if none

getVariance

double getVariance()

getStandardDeviation

double getStandardDeviation()

toString

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.

Overrides:

toString in class Object

Returns:

a string representation of this object