GroupByAggregation (cudfjni 24.12.0 API)

java.lang.Object
- ai.rapids.cudf.GroupByAggregation

public final class GroupByAggregation
extends Object

An aggregation that can be used for a reduce.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static GroupByAggregation`	`argMax()` Index of max element.
`static GroupByAggregation`	`argMin()` Index of min element.
`static GroupByAggregation`	`collectList()` Collect the values into a list.
`static GroupByAggregation`	`collectList(NullPolicy nullPolicy)` Collect the values into a list.
`static GroupByAggregation`	`collectSet()` Collect the values into a set.
`static GroupByAggregation`	`collectSet(NullPolicy nullPolicy, NullEquality nullEquality, NaNEquality nanEquality)` Collect the values into a set.
`static GroupByAggregation`	`count()` Count number of valid, a.k.a.
`static GroupByAggregation`	`count(NullPolicy nullPolicy)` Count number of elements.
`static GroupByAggregation`	`createTDigest(int delta)` Compute a t-digest from on a fixed-width numeric input column.
`boolean`	`equals(Object other)`
`int`	`hashCode()`
`static GroupByAggregation`	`histogram()` Histogram aggregation, computing the frequencies for each unique row.
`static GroupByAggregation`	`M2()` Sum of square of differences from mean.
`static GroupByAggregation`	`max()` Max Aggregation
`static GroupByAggregation`	`mean()` Arithmetic mean reduction.
`static GroupByAggregation`	`median()` Median reduction.
`static GroupByAggregation`	`mergeHistogram()` MergeHistogram aggregation, to merge multiple histograms.
`static GroupByAggregation`	`mergeLists()` Merge the partial lists produced by multiple CollectListAggregations.
`static GroupByAggregation`	`mergeM2()` Merge the partial M2 values produced by multiple instances of M2Aggregation.
`static GroupByAggregation`	`mergeSets()` Merge the partial sets produced by multiple CollectSetAggregations.
`static GroupByAggregation`	`mergeSets(NullEquality nullEquality, NaNEquality nanEquality)` Merge the partial sets produced by multiple CollectSetAggregations.
`static GroupByAggregation`	`mergeTDigest(int delta)` Merge t-digests.
`static GroupByAggregation`	`min()` Min Aggregation
`static GroupByAggregation`	`nth(int offset)` Get the nth, non-null, element in a group.
`static GroupByAggregation`	`nth(int offset, NullPolicy nullPolicy)` Get the nth element in a group.
`static GroupByAggregation`	`nunique()` Number of unique, non-null, elements.
`static GroupByAggregation`	`nunique(NullPolicy nullPolicy)` Number of unique elements.
`GroupByAggregationOnColumn`	`onColumn(int columnIndex)` Add a column to the Aggregation so it can be used on a specific column of data.
`static GroupByAggregation`	`product()` Product Aggregation.
`static GroupByAggregation`	`quantile(double... quantiles)` Aggregate to compute the specified quantiles.
`static GroupByAggregation`	`quantile(QuantileMethod method, double... quantiles)` Aggregate to compute various quantiles.
`static GroupByAggregation`	`standardDeviation()` Standard deviation aggregation with 1 as the delta degrees of freedom.
`static GroupByAggregation`	`standardDeviation(int ddof)` Standard deviation aggregation.
`static GroupByAggregation`	`sum()` Sum Aggregation
`static GroupByAggregation`	`variance()` Variance aggregation with 1 as the delta degrees of freedom.
`static GroupByAggregation`	`variance(int ddof)` Variance aggregation.

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

- Method Detail
  - onColumn
```
public GroupByAggregationOnColumn onColumn(int columnIndex)
```
    Add a column to the Aggregation so it can be used on a specific column of data.
    
    Parameters:
    
    columnIndex - the index of the column to operate on.
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - equals
```
public boolean equals(Object other)
```
    Overrides:
    
    equals in class Object
  - count
```
public static GroupByAggregation count()
```
    Count number of valid, a.k.a. non-null, elements.
  - count
```
public static GroupByAggregation count(NullPolicy nullPolicy)
```
    Count number of elements.
    
    Parameters:
    
    nullPolicy - INCLUDE if nulls should be counted. EXCLUDE if only non-null values should be counted.
  - sum
```
public static GroupByAggregation sum()
```
    Sum Aggregation
  - product
```
public static GroupByAggregation product()
```
    Product Aggregation.
  - argMax
```
public static GroupByAggregation argMax()
```
    Index of max element. Please note that when using this aggregation if the data is not already sorted by the grouping keys it may be automatically sorted prior to doing the aggregation. This would result in an index into the sorted data being returned.
  - argMin
```
public static GroupByAggregation argMin()
```
    Index of min element. Please note that when using this aggregation if the data is not already sorted by the grouping keys it may be automatically sorted prior to doing the aggregation. This would result in an index into the sorted data being returned.
  - min
```
public static GroupByAggregation min()
```
    Min Aggregation
  - max
```
public static GroupByAggregation max()
```
    Max Aggregation
  - mean
```
public static GroupByAggregation mean()
```
    Arithmetic mean reduction.
  - M2
```
public static GroupByAggregation M2()
```
    Sum of square of differences from mean.
  - variance
```
public static GroupByAggregation variance()
```
    Variance aggregation with 1 as the delta degrees of freedom.
  - variance
```
public static GroupByAggregation variance(int ddof)
```
    Variance aggregation.
    
    Parameters:
    
    ddof - delta degrees of freedom. The divisor used in calculation of variance is N - ddof, where N is the population size.
  - standardDeviation
```
public static GroupByAggregation standardDeviation()
```
    Standard deviation aggregation with 1 as the delta degrees of freedom.
  - standardDeviation
```
public static GroupByAggregation standardDeviation(int ddof)
```
    Standard deviation aggregation.
    
    Parameters:
    
    ddof - delta degrees of freedom. The divisor used in calculation of std is N - ddof, where N is the population size.
  - quantile
```
public static GroupByAggregation quantile(double... quantiles)
```
    Aggregate to compute the specified quantiles. Uses linear interpolation by default.
  - quantile
```
public static GroupByAggregation quantile(QuantileMethod method,
                                          double... quantiles)
```
    Aggregate to compute various quantiles.
  - median
```
public static GroupByAggregation median()
```
    Median reduction.
  - nunique
```
public static GroupByAggregation nunique()
```
    Number of unique, non-null, elements.
  - nunique
```
public static GroupByAggregation nunique(NullPolicy nullPolicy)
```
    Number of unique elements.
    
    Parameters:
    
    nullPolicy - INCLUDE if nulls should be counted else EXCLUDE. If nulls are counted they compare as equal so multiple null values in a range would all only increase the count by 1.
  - nth
```
public static GroupByAggregation nth(int offset)
```
    Get the nth, non-null, element in a group.
    
    Parameters:
    
    offset - the offset to look at. Negative numbers go from the end of the group. Any value outside of the group range results in a null.
  - nth
```
public static GroupByAggregation nth(int offset,
                                     NullPolicy nullPolicy)
```
    Get the nth element in a group.
    
    Parameters:
    
    offset - the offset to look at. Negative numbers go from the end of the group. Any value outside of the group range results in a null.
    
    nullPolicy - INCLUDE if nulls should be included in the aggregation or EXCLUDE if they should be skipped.
  - collectList
```
public static GroupByAggregation collectList()
```
    Collect the values into a list. Nulls will be skipped.
  - collectList
```
public static GroupByAggregation collectList(NullPolicy nullPolicy)
```
    Collect the values into a list.
    
    Parameters:
    
    nullPolicy - Indicates whether to include/exclude nulls during collection.
  - collectSet
```
public static GroupByAggregation collectSet()
```
    Collect the values into a set. All null values will be excluded, and all NaN values are regarded as unique instances.
  - collectSet
```
public static GroupByAggregation collectSet(NullPolicy nullPolicy,
                                            NullEquality nullEquality,
                                            NaNEquality nanEquality)
```
    Collect the values into a set.
    
    Parameters:
    
    nullPolicy - Indicates whether to include/exclude nulls during collection.
    
    nullEquality - Flag to specify whether null entries within each list should be considered equal.
    
    nanEquality - Flag to specify whether NaN values in floating point column should be considered equal.
  - mergeLists
```
public static GroupByAggregation mergeLists()
```
    Merge the partial lists produced by multiple CollectListAggregations. NOTICE: The partial lists to be merged should NOT include any null list element (but can include null list entries).
  - mergeSets
```
public static GroupByAggregation mergeSets()
```
    Merge the partial sets produced by multiple CollectSetAggregations. Each null/NaN value will be regarded as a unique instance.
  - mergeSets
```
public static GroupByAggregation mergeSets(NullEquality nullEquality,
                                           NaNEquality nanEquality)
```
    Merge the partial sets produced by multiple CollectSetAggregations.
    
    Parameters:
    
    nullEquality - Flag to specify whether null entries within each list should be considered equal.
    
    nanEquality - Flag to specify whether NaN values in floating point column should be considered equal.
  - mergeM2
```
public static GroupByAggregation mergeM2()
```
    Merge the partial M2 values produced by multiple instances of M2Aggregation.
  - createTDigest
```
public static GroupByAggregation createTDigest(int delta)
```
    Compute a t-digest from on a fixed-width numeric input column.
    
    Parameters:
    
    delta - Required accuracy (number of buckets).
    
    Returns:
    
    A list of centroids per grouping, where each centroid has a mean value and a weight. The number of centroids will be <= delta.
  - mergeTDigest
```
public static GroupByAggregation mergeTDigest(int delta)
```
    Merge t-digests.
    
    Parameters:
    
    delta - Required accuracy (number of buckets).
    
    Returns:
    
    A list of centroids per grouping, where each centroid has a mean value and a weight. The number of centroids will be <= delta.
  - histogram
```
public static GroupByAggregation histogram()
```
    Histogram aggregation, computing the frequencies for each unique row. A histogram is given as a lists column, in which the first child stores unique rows from the input values and the second child stores their corresponding frequencies.
    
    Returns:
    
    A lists of structs column in which each list contains a histogram corresponding to an input key.
  - mergeHistogram
```
public static GroupByAggregation mergeHistogram()
```
    MergeHistogram aggregation, to merge multiple histograms.
    
    Returns:
    
    A new histogram in which the frequencies of the unique rows are sum up.

Class GroupByAggregation

Method Summary

Methods inherited from class java.lang.Object

Method Detail

onColumn

hashCode

equals

count

count

sum

product

argMax

argMin

min

max

mean

M2

variance

variance

standardDeviation

standardDeviation

quantile

quantile

median

nunique

nunique

nth

nth

collectList

collectList

collectSet

collectSet

mergeLists

mergeSets

mergeSets

mergeM2

createTDigest

mergeTDigest

histogram

mergeHistogram