FisherValues

java.lang.Object
- net.talvi.puffinplot.data.FisherValues

All Implemented Interfaces:

FisherParams
```
public class FisherValues
extends java.lang.Object
implements FisherParams
```
This class calculates Fisher (1953) spherical statistics on sets of vectors.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static FisherValues`	`calculate(java.util.Collection<Vec3> vectors)` Returns a set of Fisherian statistics, calculated using the Fisher (1953) method, for a collection of vectors.
`double`	`getA95()` Returns the alpha-95 value denoting the 95% confidence interval.
`java.util.List<Vec3>`	`getDirections()` Returns a list of unit vectors representing the directions of the vectors on which these statistics were calculated.
`static java.util.List<java.lang.String>`	`getEmptyFields()` Returns a list of empty strings equal in length to the number of parameters.
`static java.util.List<java.lang.String>`	`getHeaders()` Returns the headers describing the parameters as a list of strings.
`double`	`getK()` Returns the k-value, an estimate of the precision parameter κ.
`Vec3`	`getMeanDirection()` Returns the mean direction.
`int`	`getN()` Returns N, the number of directions analysed.
`double`	`getR()` Returns R, the total unit vector path length.
`java.lang.String`	`toString()` Returns a string representation of the parameters.
`java.util.List<java.lang.String>`	`toStrings()` Returns the statistical parameters as a list of strings.
`static java.util.List<java.lang.String>`	`toStrings(FisherValues fisherValues)` Returns the statistical parameters as a list of strings.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface net.talvi.puffinplot.data.FisherParams
isA95Valid

- Method Detail
  - calculate
```
public static FisherValues calculate(java.util.Collection<Vec3> vectors)
```
    Returns a set of Fisherian statistics, calculated using the Fisher (1953) method, for a collection of vectors. The vectors do not need to be normalized; since Fisherian statistics are purely directional, their magnitudes will not influence the result. Passing an empty collection of vectors will return a null FisherValues object. Passing a singleton collection will return a FisherValues object with the direction of the single vector as the mean, but the a95 and k values are entirely undefined; they may be NaN or infinity.
    The a95 value is not guaranteed to represent a real number: some sets of directions may produce an undefined (NaN or infinite) a95. This is a consequence of the definition, rather than of the implementation here; see equation 6.21 in Butler (1992) and note that R may be arbitrarily small, putting the RHS out of the domain of the cosine function. (Theoretically R may even be zero, but this is extremely unlikely for any real data set.)
    
    Parameters:
    
    vectors - the points on which to calculate statistics
    
    Returns:
    
    the Fisherian statistics for the supplied vectors
  - getA95
```
public double getA95()
```
    Description copied from interface: FisherParams
    
    Returns the alpha-95 value denoting the 95% confidence interval. The returned value is in degrees.
    
    Specified by:
    
    getA95 in interface FisherParams
    
    Returns:
    
    the alpha-95 value denoting the 95% confidence interval
  - getK
```
public double getK()
```
    Description copied from interface: FisherParams
    
    Returns the k-value, an estimate of the precision parameter κ.
    
    Specified by:
    
    getK in interface FisherParams
    
    Returns:
    
    the k-value, an estimate of the precision parameter κ
  - getN
```
public int getN()
```
    Description copied from interface: FisherParams
    
    Returns N, the number of directions analysed. In the case of the McFadden & McElhinny (1988), this corresponds to the number of great circles, and does not include any endpoints (direct observations) used in the calculation. (See the paper for details.)
    
    Specified by:
    
    getN in interface FisherParams
    
    Returns:
    
    N, the number of directions analysed
  - getR
```
public double getR()
```
    Description copied from interface: FisherParams
    
    Returns R, the total unit vector path length. For standard Fisher (1953) statistics, R is the length of the sum of the unit vectors corresponding to the directions being analysed. For McFadden & McElhinny (1988) statistics, R has a similar interpretation; see the paper for details.
    
    Specified by:
    
    getR in interface FisherParams
    
    Returns:
    
    R, the total unit vector path length.
  - getMeanDirection
```
public Vec3 getMeanDirection()
```
    Description copied from interface: FisherParams
    
    Returns the mean direction.
    
    Specified by:
    
    getMeanDirection in interface FisherParams
    
    Returns:
    
    the mean direction
  - getDirections
```
public java.util.List<Vec3> getDirections()
```
    Returns a list of unit vectors representing the directions of the vectors on which these statistics were calculated.
    
    Returns:
    
    the directions of the vectors on which these statistics were calculated
  - toStrings
```
public java.util.List<java.lang.String> toStrings()
```
    Returns the statistical parameters as a list of strings. The order of the parameters is the same as the order of the headers provided by getHeaders().
    
    Returns:
    
    the statistical parameters as a list of strings
    
    See Also:
    
    toStrings(net.talvi.puffinplot.data.FisherValues)
  - toStrings
```
public static java.util.List<java.lang.String> toStrings(FisherValues fisherValues)
```
    Returns the statistical parameters as a list of strings. The order of the parameters is the same as the order of the headers provided by getHeaders(). It returns the same result as the corresponding instance method for any non-null input, but (unlike the instance method) also works for a null FisherValues.
    
    Parameters:
    
    fisherValues - the Fisher parameters to return as strings
    
    Returns:
    
    the statistical parameters as a list of strings, or a list of empty strings if fisherValues was null
    
    See Also:
    
    toStrings()
  - toString
```
public java.lang.String toString()
```
    Returns a string representation of the parameters.
    
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    
    a string representation of the parameters
  - getHeaders
```
public static java.util.List<java.lang.String> getHeaders()
```
    Returns the headers describing the parameters as a list of strings.
    
    Returns:
    
    the headers describing the parameters
  - getEmptyFields
```
public static java.util.List<java.lang.String> getEmptyFields()
```
    Returns a list of empty strings equal in length to the number of parameters.
    
    Returns:
    
    a list of empty strings equal in length to the number of parameters

Class FisherValues

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface net.talvi.puffinplot.data.FisherParams

Method Detail

calculate

getA95

getK

getN

getR

getMeanDirection

getDirections

toStrings

toStrings

toString

getHeaders

getEmptyFields