@Beta @GwtIncompatible public final class PairedStats extends Object implements Serializable
|Modifier and Type||Method and Description|
Returns the number of pairs in the dataset.
Indicates whether some other object is "equal to" this one.
Returns a hash code value for the object.
Returns a linear transformation giving the best fit to the data according to Ordinary Least Squares linear regression of
Returns the Pearson's or product-moment correlation coefficient of the values.
Returns the population covariance of the values.
Returns the sample covariance of the values.
Gets a byte array representation of this instance.
Returns a string representation of the object.
Returns the statistics on the
Returns the statistics on the
public long count()
public double populationCovariance()
This is guaranteed to return zero if the dataset contains a single pair of finite values. It is not guaranteed to return zero when the dataset consists of the same pair of values multiple times, due to numerical errors.
IllegalStateException- if the dataset is empty
public double sampleCovariance()
This is not guaranteed to return zero when the dataset consists of the same pair of values multiple times, due to numerical errors.
IllegalStateException- if the dataset is empty or contains a single pair of values
public double pearsonsCorrelationCoefficient()
yvalues must both have non-zero population variance (i.e.
xStats().populationVariance() > 0.0 && yStats().populationVariance() > 0.0). The result is not guaranteed to be exactly +/-1 even when the data are perfectly (anti-)correlated, due to numerical errors. However, it is guaranteed to be in the inclusive range [-1, +1].
IllegalStateException- if the dataset is empty or contains a single pair of values, or either the
ydataset has zero population variance
public LinearTransformation leastSquaresFit()
yas a function of
x. The count must be greater than one, and either the
ydata must have a non-zero population variance (i.e.
xStats().populationVariance() > 0.0 || yStats().populationVariance() > 0.0). The result is guaranteed to be horizontal if there is variance in the
xdata but not the
ydata, and vertical if there is variance in the
ydata but not the
This fit minimizes the root-mean-square error in
y as a function of
error is defined as the square root of the mean of the squares of the differences between the
y values of the data and the values predicted by the fit for the
values (i.e. it is the square root of the mean of the squares of the vertical distances between
the data points and the best fit line). For this fit, this error is a fraction
R*R) of the population standard deviation of
R is the Pearson's
correlation coefficient (as given by
The corresponding root-mean-square error in
x as a function of
y is a
sqrt(1/(R*R) - 1) of the population standard deviation of
x. This fit
does not normally minimize that error: to do that, you should swap the roles of
IllegalStateException- if the dataset is empty or contains a single pair of values, or both the
ydataset must have zero population variance
equals method implements an equivalence relation
on non-null object references:
trueif and only if
y, multiple invocations of
trueor consistently return
false, provided no information used in
equalscomparisons on the objects is modified.
equals method for class
the most discriminating possible equivalence relation on objects;
that is, for any non-null reference values
y, this method returns
true if and only
y refer to the same object
x == y has the value
Note that it is generally necessary to override the
method whenever this method is overridden, so as to maintain the
general contract for the
hashCode method, which states
that equal objects must have equal hash codes.
Note: This tests exact equality of the calculated statistics, including the floating
point values. Two instances are guaranteed to be considered equal if one is copied from the
second = new PairedStatsAccumulator().addAll(first).snapshot(), if both
were obtained by calling
snapshot() on the same
adding any values in between the two calls, or if one is obtained from the other after
round-tripping through java serialization. However, floating point rounding errors mean that it
may be false for some instances where the statistics are mathematically equal, including
instances constructed from the same values in a different order... or (in the general case)
even in the same order. (It is guaranteed to return true for instances constructed from the
same values in the same order if
strictfp is in effect, or if the system architecture
public int hashCode()
The general contract of
hashCodemethod must consistently return the same integer, provided no information used in
equalscomparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
equals(Object)method, then calling the
hashCodemethod on each of the two objects must produce the same integer result.
Object.equals(java.lang.Object)method, then calling the
hashCodemethod on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.
As much as is reasonably practical, the hashCode method defined by
Object does return distinct integers for distinct
objects. (This is typically implemented by converting the internal
address of the object into an integer, but this implementation
technique is not required by the
Java™ programming language.)
Note: This hash code is consistent with exact equality of the calculated statistics,
including the floating point values. See the note on
equals(java.lang.Object) for details.
toStringmethod returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.
toString method for class
returns a string consisting of the name of the class of which the
object is an instance, the at-sign character `
the unsigned hexadecimal representation of the hash code of the
object. In other words, this method returns a string equal to the
getClass().getName() + '@' + Integer.toHexString(hashCode())
public byte toByteArray()
Note: No guarantees are made regarding stability of the representation between versions.
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