NumericSummaryAggregator (Flink : Java 1.19.2-cp2 API)

java.lang.Object
- org.apache.flink.api.java.summarize.aggregation.NumericSummaryAggregator<T>

Type Parameters:

T - numeric type to aggregrate and create a summary, e.g. Integer, DoubleValue

All Implemented Interfaces:

Serializable, Aggregator<T,NumericColumnSummary<T>>

Direct Known Subclasses:

DoubleSummaryAggregator, FloatSummaryAggregator, IntegerSummaryAggregator, LongSummaryAggregator, ShortSummaryAggregator
```
@Internal
public abstract class NumericSummaryAggregator<T extends Number>
extends Object
implements Aggregator<T,NumericColumnSummary<T>>
```
Generic aggregator for all numeric types creates a summary of a column of numbers.
Uses the Kahan summation algorithm to avoid numeric instability when computing variance. The algorithm is described in: "Scalable and Numerically Stable Descriptive Statistics in SystemML", Tian et al, International Conference on Data Engineering 2012
Implementation that couldn't be generic for all numbers was pushed to subclasses. For example, there isn't a generic way to calculate min, max, sum, isNan, isInfinite for all numeric types so subclasses must implement these.

See Also:

Serialized Form

Constructor Summary

Constructors
Constructor Description

NumericSummaryAggregator()

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`aggregate(T value)`	Add a value to the current aggregation.
`void`	`combine(Aggregator<T,NumericColumnSummary<T>> otherSameType)`	combine two aggregations.
`protected abstract Aggregator<T,T>`	`initMax()`
`protected abstract Aggregator<T,T>`	`initMin()`
`protected abstract Aggregator<T,T>`	`initSum()`
`protected abstract boolean`	`isInfinite(T number)`
`protected abstract boolean`	`isNan(T number)`
`NumericColumnSummary<T>`	`result()`	Provide the final result of the aggregation.

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

- Constructor Detail
  - NumericSummaryAggregator
```
public NumericSummaryAggregator()
```
- Method Detail
  - aggregate
```
public void aggregate(T value)
```
    Add a value to the current aggregation.
    
    Specified by:
    
    aggregate in interface Aggregator<T extends Number,NumericColumnSummary<T extends Number>>
  - combine
```
public void combine(Aggregator<T,NumericColumnSummary<T>> otherSameType)
```
    combine two aggregations.
    
    Specified by:
    
    combine in interface Aggregator<T extends Number,NumericColumnSummary<T extends Number>>
  - result
```
public NumericColumnSummary<T> result()
```
    Description copied from interface: Aggregator
    
    Provide the final result of the aggregation.
    
    Specified by:
    
    result in interface Aggregator<T extends Number,NumericColumnSummary<T extends Number>>
  - initMin
```
protected abstract Aggregator<T,T> initMin()
```
  - initMax
```
protected abstract Aggregator<T,T> initMax()
```
  - initSum
```
protected abstract Aggregator<T,T> initSum()
```
  - isNan
```
protected abstract boolean isNan(T number)
```
  - isInfinite
```
protected abstract boolean isInfinite(T number)
```