Statistics (Geotools modules 27-SNAPSHOT API)

Object
- Statistics

All Implemented Interfaces:

Serializable, Cloneable

Direct Known Subclasses:

Statistics.Delta
```
public class Statistics
extends Object
implements Cloneable, Serializable
```
Holds some statistics about a series of sample values. Given a series of sample values s₀, s₁, s₂, s₃..., this class computes minimum, maximum, mean, root mean square and standard deviation. Statistics are computed on the fly; the sample values are never stored in memory.
An instance of Statistics is initially empty (i.e. all statistical values are set to NaN). The statistics are updated every time an add(double) method is invoked with a non-NaN value. A typical usage of this class is:
```
 double[] data = new double[1000];
 // (Compute some data values here...)

 Statistics stats = new Statistics();
 for (int i=0; i<data.length; i++) {
     stats.add(data[i]);
 }
 System.out.println(stats);
 
```
Since:

2.0

Author:

Martin Desruisseaux (IRD)

See Also:

Serialized Form

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class Statistics.Delta
Holds some statistics about a series of sample values and the difference between them.

Nested Classes
Modifier and Type	Class and Description
`static class`	`Statistics.Delta` Holds some statistics about a series of sample values and the difference between them.

Constructor Summary

Constructors
Constructor and Description

Statistics()
Constructs an initially empty set of statistics.

Constructors
Constructor and Description
`Statistics()` Constructs an initially empty set of statistics.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`add(double sample)` Updates statistics for the specified sample.
`void`	`add(long sample)` Updates statistics for the specified sample.
`void`	`add(Statistics stats)` Updates statistics with all samples from the specified `stats`.
`Statistics`	`clone()` Returns a clone of this statistics.
`int`	`count()` Returns the number of samples, excluding `NaN` values.
`int`	`countNaN()` Returns the number of `NaN` samples.
`boolean`	`equals(Object obj)` Tests this statistics with the specified object for equality.
`int`	`hashCode()` Returns a hash code value for this statistics.
`double`	`maximum()` Returns the maximum sample value, or `NaN` if none.
`double`	`mean()` Returns the mean value, or `NaN` if none.
`double`	`minimum()` Returns the minimum sample value, or `NaN` if none.
`double`	`range()` Returns the range of sample values.
`void`	`reset()` Resets the statistics to their initial `NaN` values.
`double`	`rms()` Returns the root mean square, or `NaN` if none.
`double`	`standardDeviation(boolean allPopulation)` Retourne l'écart type des échantillons par rapport à la moyenne.
`String`	`toString()` Returns a string representation of this statistics.
`String`	`toString(Locale locale, boolean tabulations)` Returns a localized string representation of this statistics.

Methods inherited from class Object
finalize, getClass, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - Statistics
```
public Statistics()
```
    Constructs an initially empty set of statistics. All statistical values are initialized to Double.NaN.
- Method Detail
  - reset
```
public void reset()
```
    Resets the statistics to their initial NaN values. This method reset this object state as if it was just created.
  - add
```
public void add(double sample)
```
    Updates statistics for the specified sample. This add method is usually invoked inside a for loop.
    
    Parameters:
    
    sample - The sample value. NaN values are ignored.
    
    See Also:
    
    add(long), add(Statistics)
  - add
```
public void add(long sample)
```
    Updates statistics for the specified sample. This add method is usually invoked inside a for loop.
    
    Parameters:
    
    sample - The sample value.
    
    See Also:
    
    add(double), add(Statistics)
  - add
```
public void add(Statistics stats)
```
    Updates statistics with all samples from the specified stats. Invoking this method is equivalent (except for rounding errors) to invoking add for all samples that were added to stats.
    
    Parameters:
    
    stats - The statistics to be added to this, or null if none.
  - countNaN
```
public int countNaN()
```
    Returns the number of NaN samples. NaN samples are ignored in all other statitical computation. This method count them for information purpose only.
  - count
```
public int count()
```
    Returns the number of samples, excluding NaN values.
  - minimum
```
public double minimum()
```
    Returns the minimum sample value, or NaN if none.
    
    See Also:
    
    maximum()
  - maximum
```
public double maximum()
```
    Returns the maximum sample value, or NaN if none.
    
    See Also:
    
    minimum()
  - range
```
public double range()
```
    Returns the range of sample values. This is equivalent to maximum - minimum, except for rounding error. If no samples were added, then returns NaN.
    
    See Also:
    
    minimum(), maximum()
  - mean
```
public double mean()
```
    Returns the mean value, or NaN if none.
  - rms
```
public double rms()
```
    Returns the root mean square, or NaN if none.
  - standardDeviation
```
public double standardDeviation(boolean allPopulation)
```
    Retourne l'écart type des échantillons par rapport à la moyenne. Si les données fournies aux différentes méthodes add(...) se distribuent selon une loi normale, alors l'écart type est la distance de part et d'autre de la moyenne dans lequel se trouveraient environ 84% des données. Le tableau ci-dessous donne le pourcentage approximatif des données que l'on trouve de part et d'autre de la moyenne à des distances telles que 2 ou 3 fois l'écart-type.
    
    0.5 69.1%
    
    1.0 84.2%
    
    1.5 93.3%
    
    2.0 97.7%
    
    3.0 99.9%
    
    Parameters:
    
    allPopulation - La valeur true indique que les données fournies aux différentes méthodes add(...) représentent l'ensemble de la polulation. La valeur false indique que ces données ne représentent qu'un échantillon de la population, ce qui est généralement le cas. Si le nombre de données est élevé, alors les valeurs true et false donneront sensiblement les mêmes résultats.
  - clone
```
public Statistics clone()
```
    Returns a clone of this statistics.
    
    Overrides:
    
    clone in class Object
    
    Returns:
    
    A copy of this object.
    
    See Also:
    
    Object.clone()
  - equals
```
public boolean equals(Object obj)
```
    Tests this statistics with the specified object for equality.
    
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Returns a hash code value for this statistics.
    
    Overrides:
    
    hashCode in class Object
  - toString
```
public final String toString()
```
    Returns a string representation of this statistics. This method invokes toString(Locale, boolean) using the default locale and spaces separator.
    
    Overrides:
    
    toString in class Object
  - toString
```
public String toString(Locale locale,
                       boolean tabulations)
```
    Returns a localized string representation of this statistics. This string will span multiple lines, one for each statistical value. For example:
    Compte: 8726 Minimum: 6.853 Maximum: 8.259 Moyenne: 7.421 RMS: 7.846 Écart-type: 6.489
    If tabulations is true, then labels (e.g. "Minimum") and values (e.g. "6.853") are separated by tabulations. Otherwise, they are separated by spaces.

0.5	69.1%
1.0	84.2%
1.5	93.3%
2.0	97.7%
3.0	99.9%

Class Statistics

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class Object

Constructor Detail

Statistics

Method Detail

reset

add

add

add

countNaN

count

minimum

maximum

range

mean

rms

standardDeviation

clone

equals

hashCode

toString

toString