java.lang.Object
- org.apache.datasketches.quantiles.ItemsSketch<T>

Type Parameters:

T - The sketch data type

All Implemented Interfaces:

QuantilesAPI, QuantilesGenericAPI<T>
```
public final class ItemsSketch<T>
extends Object
implements QuantilesGenericAPI<T>
```
This is an implementation of the Low Discrepancy Mergeable Quantiles Sketch, using generic items, described in section 3.2 of the journal version of the paper "Mergeable Summaries" by Agarwal, Cormode, Huang, Phillips, Wei, and Yi:
Reference:

A k of 128 produces a normalized, rank error of about 1.7%. For example, the median returned from getQuantile(0.5) will be between the actual quantiles from the hypothetically sorted array of input quantiles at normalized ranks of 0.483 and 0.517, with a confidence of about 99%.

The size of an ItemsSketch is very dependent on the size of the generic Items input into the sketch, so there is no comparable size table as there is for the DoublesSketch.

See Also:

QuantilesAPI

Nested Class Summary
- Nested classes/interfaces inherited from interface org.apache.datasketches.quantilescommon.QuantilesGenericAPI
  QuantilesGenericAPI.GenericPartitionBoundaries<T>

Field Summary

Fields
Modifier and Type Field Description

static Random rand
Setting the seed makes the results of the sketch deterministic if the input items are received in exactly the same order.
- Fields inherited from interface org.apache.datasketches.quantilescommon.QuantilesAPI
  EMPTY_MSG, MEM_REQ_SVR_NULL_MSG, NOT_SINGLE_ITEM_MSG, TGT_IS_READ_ONLY_MSG, UNSUPPORTED_MSG

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`ItemsSketch<T>`	`downSample(int newK)`	From an existing sketch, this creates a new sketch that can have a smaller K.
`double[]`	`getCDF(T[] splitPoints)`	This is equivalent to `getCDF(splitPoints, INCLUSIVE)`
`double[]`	`getCDF(T[] splitPoints, QuantileSearchCriteria searchCrit)`	Returns an approximation to the Cumulative Distribution Function (CDF) of the input stream as a monotonically increasing array of double ranks (or cumulative probabilities) on the interval [0.0, 1.0], given a set of splitPoints.
`static <T> ItemsSketch<T>`	`getInstance(Class<T> clazz, int k, Comparator<? super T> comparator)`	Obtains a new instance of an ItemsSketch.
`static <T> ItemsSketch<T>`	`getInstance(Class<T> clazz, Comparator<? super T> comparator)`	Obtains a new instance of an ItemsSketch using the DEFAULT_K.
`static <T> ItemsSketch<T>`	`getInstance(Class<T> clazz, org.apache.datasketches.memory.Memory srcMem, Comparator<? super T> comparator, ArrayOfItemsSerDe<T> serDe)`	Heapifies the given srcMem, which must be a Memory image of a ItemsSketch
`int`	`getK()`	Gets the user configured parameter k, which controls the accuracy of the sketch and its memory space usage.
`static int`	`getKFromEpsilon(double epsilon, boolean pmf)`	Gets the approximate k to use given epsilon, the normalized rank error.
`T`	`getMaxItem()`	Returns the maximum item of the stream.
`T`	`getMinItem()`	Returns the minimum item of the stream.
`long`	`getN()`	Gets the length of the input stream.
`double`	`getNormalizedRankError(boolean pmf)`	Gets the approximate rank error of this sketch normalized as a fraction between zero and one.
`static double`	`getNormalizedRankError(int k, boolean pmf)`	Gets the normalized rank error given k and pmf.
`int`	`getNumRetained()`	Gets the number of quantiles retained by the sketch.
`QuantilesGenericAPI.GenericPartitionBoundaries<T>`	`getPartitionBoundaries(int numEquallyWeighted, QuantileSearchCriteria searchCrit)`	This method returns an instance of `GenericPartitionBoundaries` which provides sufficient information for the user to create the given number of equally weighted partitions.
`double[]`	`getPMF(T[] splitPoints)`	This is equivalent to `getPMF(splitPoints, INCLUSIVE)`
`double[]`	`getPMF(T[] splitPoints, QuantileSearchCriteria searchCrit)`	Returns an approximation to the Probability Mass Function (PMF) of the input stream as an array of probability masses as doubles on the interval [0.0, 1.0], given a set of splitPoints.
`T`	`getQuantile(double rank)`	This is equivalent to `getQuantile(rank, INCLUSIVE)`
`T`	`getQuantile(double rank, QuantileSearchCriteria searchCrit)`	Gets the approximate quantile of the given normalized rank and the given search criterion.
`T`	`getQuantileLowerBound(double rank)`	Gets the lower bound of the quantile confidence interval in which the quantile of the given rank exists.
`T[]`	`getQuantiles(double[] ranks)`	This is equivalent to `getQuantiles(ranks, INCLUSIVE)`
`T[]`	`getQuantiles(double[] ranks, QuantileSearchCriteria searchCrit)`	Gets an array of quantiles from the given array of normalized ranks.
`T`	`getQuantileUpperBound(double rank)`	Gets the upper bound of the quantile confidence interval in which the true quantile of the given rank exists.
`double`	`getRank(T quantile)`	This is equivalent to `getRank(T quantile, INCLUSIVE)`
`double`	`getRank(T quantile, QuantileSearchCriteria searchCrit)`	Gets the normalized rank corresponding to the given a quantile.
`double`	`getRankLowerBound(double rank)`	Gets the lower bound of the rank confidence interval in which the true rank of the given rank exists.
`double[]`	`getRanks(T[] quantiles)`	This is equivalent to `getRanks(quantiles, INCLUSIVE)`
`double[]`	`getRanks(T[] quantiles, QuantileSearchCriteria searchCrit)`	Gets an array of normalized ranks corresponding to the given array of quantiles and the given search criterion.
`double`	`getRankUpperBound(double rank)`	Gets the upper bound of the rank confidence interval in which the true rank of the given rank exists.
`Class<T>`	`getSketchType()`
`GenericSortedView<T>`	`getSortedView()`	Gets the sorted view of this sketch
`boolean`	`hasMemory()`	Returns true if this sketch's data structure is backed by Memory or WritableMemory.
`boolean`	`isDirect()`	Returns true if this sketch's data structure is off-heap (a.k.a., Direct or Native memory).
`boolean`	`isEmpty()`	Returns true if this sketch is empty.
`boolean`	`isEstimationMode()`	Returns true if this sketch is in estimation mode.
`boolean`	`isReadOnly()`	Returns true if this sketch is read only.
`QuantilesGenericSketchIterator<T>`	`iterator()`	Gets the iterator for this sketch, which is not sorted.
`void`	`putMemory(org.apache.datasketches.memory.WritableMemory dstMem, ArrayOfItemsSerDe<T> serDe)`	Puts the current sketch into the given Memory if there is sufficient space.
`void`	`reset()`	Resets this sketch to the empty state.
`byte[]`	`toByteArray(boolean ordered, ArrayOfItemsSerDe<T> serDe)`	Serialize this sketch to a byte array form.
`byte[]`	`toByteArray(ArrayOfItemsSerDe<T> serDe)`	Serialize this sketch to a byte array form.
`String`	`toString()`	Returns a summary of the key parameters of the sketch.
`String`	`toString(boolean sketchSummary, boolean dataDetail)`	Returns summary information about this sketch.
`static String`	`toString(byte[] byteArr)`	Returns a human readable string of the preamble of a byte array image of an ItemsSketch.
`static String`	`toString(org.apache.datasketches.memory.Memory mem)`	Returns a human readable string of the preamble of a Memory image of an ItemsSketch.
`void`	`update(T item)`	Updates this sketch with the given item.

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

Methods inherited from interface org.apache.datasketches.quantilescommon.QuantilesGenericAPI
getPartitionBoundaries

- Field Detail
  - rand
```
public static final Random rand
```
    Setting the seed makes the results of the sketch deterministic if the input items are received in exactly the same order. This is only useful when performing test comparisons, otherwise is not recommended.
- Method Detail
  - getInstance
```
public static <T> ItemsSketch<T> getInstance(Class<T> clazz,
                                             Comparator<? super T> comparator)
```
    Obtains a new instance of an ItemsSketch using the DEFAULT_K.
    
    Type Parameters:
    
    T - The sketch data type
    
    Parameters:
    
    clazz - the given class of T
    
    comparator - to compare items
    
    Returns:
    
    an ItemSketch<T>.
  - getInstance
```
public static <T> ItemsSketch<T> getInstance(Class<T> clazz,
                                             int k,
                                             Comparator<? super T> comparator)
```
    Obtains a new instance of an ItemsSketch.
    
    Type Parameters:
    
    T - The sketch data type
    
    Parameters:
    
    clazz - the given class of T
    
    k - Parameter that controls space usage of sketch and accuracy of estimates. Must be greater than 2 and less than 65536 and a power of 2.
    
    comparator - to compare items
    
    Returns:
    
    an ItemSketch<T>.
  - getInstance
```
public static <T> ItemsSketch<T> getInstance(Class<T> clazz,
                                             org.apache.datasketches.memory.Memory srcMem,
                                             Comparator<? super T> comparator,
                                             ArrayOfItemsSerDe<T> serDe)
```
    Heapifies the given srcMem, which must be a Memory image of a ItemsSketch
    
    Type Parameters:
    
    T - The sketch data type
    
    Parameters:
    
    clazz - the given class of T
    
    srcMem - a Memory image of a sketch. See Memory
    
    comparator - to compare items
    
    serDe - an instance of ArrayOfItemsSerDe
    
    Returns:
    
    a ItemSketch<T> on the Java heap.
  - getCDF
```
public double[] getCDF(T[] splitPoints)
```
    Description copied from interface: QuantilesGenericAPI
    
    This is equivalent to getCDF(splitPoints, INCLUSIVE)
    
    Specified by:
    
    getCDF in interface QuantilesGenericAPI<T>
    
    Parameters:
    
    splitPoints - an array of m unique, monotonically increasing items.
    
    Returns:
    
    a discrete CDF array of m+1 double ranks (or cumulative probabilities) on the interval [0.0, 1.0].
  - getCDF
```
public double[] getCDF(T[] splitPoints,
                       QuantileSearchCriteria searchCrit)
```
    Description copied from interface: QuantilesGenericAPI
    
    Returns an approximation to the Cumulative Distribution Function (CDF) of the input stream as a monotonically increasing array of double ranks (or cumulative probabilities) on the interval [0.0, 1.0], given a set of splitPoints.
    The resulting approximations have a probabilistic guarantee that can be obtained from the getNormalizedRankError(false) function.
    Specified by:
    
    getCDF in interface QuantilesGenericAPI<T>
    
    Parameters:
    
    splitPoints - an array of m unique, monotonically increasing items (of the same type as the input items) that divide the item input domain into m+1 overlapping intervals.
    The start of each interval is below the lowest item retained by the sketch corresponding to a zero rank or zero probability, and the end of the interval is the rank or cumulative probability corresponding to the split point.
    
    The (m+1)th interval represents 100% of the distribution represented by the sketch and consistent with the definition of a cumulative probability distribution, thus the (m+1)th rank or probability in the returned array is always 1.0.
    
    If a split point exactly equals a retained item of the sketch and the search criterion is:
    
    INCLUSIVE, the resulting cumulative probability will include that item.
    
    EXCLUSIVE, the resulting cumulative probability will not include the weight of that split point.
    
    It is not recommended to include either the minimum or maximum items of the input stream.
    
    searchCrit - the desired search criteria.
    
    Returns:
    
    a discrete CDF array of m+1 double ranks (or cumulative probabilities) on the interval [0.0, 1.0].
  - getSketchType
```
public Class<T> getSketchType()
```
    Returns:
    
    the sketch item type
  - getMaxItem
```
public T getMaxItem()
```
    Description copied from interface: QuantilesGenericAPI
    
    Returns the maximum item of the stream. This may be distinct from the largest item retained by the sketch algorithm.
    
    Specified by:
    
    getMaxItem in interface QuantilesGenericAPI<T>
    
    Returns:
    
    the maximum item of the stream
  - getMinItem
```
public T getMinItem()
```
    Description copied from interface: QuantilesGenericAPI
    
    Returns the minimum item of the stream. This may be distinct from the smallest item retained by the sketch algorithm.
    
    Specified by:
    
    getMinItem in interface QuantilesGenericAPI<T>
    
    Returns:
    
    the minimum item of the stream
  - getPartitionBoundaries
```
public QuantilesGenericAPI.GenericPartitionBoundaries<T> getPartitionBoundaries(int numEquallyWeighted,
                                                                                QuantileSearchCriteria searchCrit)
```
    Description copied from interface: QuantilesGenericAPI
    
    This method returns an instance of GenericPartitionBoundaries which provides sufficient information for the user to create the given number of equally weighted partitions.
    Specified by:
    
    getPartitionBoundaries in interface QuantilesGenericAPI<T>
    
    Parameters:
    
    numEquallyWeighted - an integer that specifies the number of equally weighted partitions between getMinItem() and getMaxItem(). This must be a positive integer greater than zero.
    
    A 1 will return: minItem, maxItem.
    
    A 2 will return: minItem, median quantile, maxItem.
    
    Etc.
    
    searchCrit - If INCLUSIVE, all the returned quantiles are the upper boundaries of the equally weighted partitions with the exception of the lowest returned quantile, which is the lowest boundary of the lowest ranked partition. If EXCLUSIVE, all the returned quantiles are the lower boundaries of the equally weighted partitions with the exception of the highest returned quantile, which is the upper boundary of the highest ranked partition.
    
    Returns:
    
    an instance of GenericPartitionBoundaries.
  - getPMF
```
public double[] getPMF(T[] splitPoints)
```
    Description copied from interface: QuantilesGenericAPI
    
    This is equivalent to getPMF(splitPoints, INCLUSIVE)
    
    Specified by:
    
    getPMF in interface QuantilesGenericAPI<T>
    
    Parameters:
    
    splitPoints - an array of m unique, monotonically increasing items.
    
    Returns:
    
    a PMF array of m+1 probability masses as doubles on the interval [0.0, 1.0].
  - getPMF
```
public double[] getPMF(T[] splitPoints,
                       QuantileSearchCriteria searchCrit)
```
    Description copied from interface: QuantilesGenericAPI
    
    Returns an approximation to the Probability Mass Function (PMF) of the input stream as an array of probability masses as doubles on the interval [0.0, 1.0], given a set of splitPoints.
    The resulting approximations have a probabilistic guarantee that can be obtained from the getNormalizedRankError(true) function.
    Specified by:
    
    getPMF in interface QuantilesGenericAPI<T>
    
    Parameters:
    
    splitPoints - an array of m unique, monotonically increasing items (of the same type as the input items) that divide the item input domain into m+1 consecutive, non-overlapping intervals.
    Each interval except for the end intervals starts with a split point and ends with the next split point in sequence.
    
    The first interval starts below the lowest item retained by the sketch corresponding to a zero rank or zero probability, and ends with the first split point
    
    The last (m+1)th interval starts with the last split point and ends after the last item retained by the sketch corresponding to a rank or probability of 1.0.
    
    The sum of the probability masses of all (m+1) intervals is 1.0.
    
    If the search criterion is:
    
    INCLUSIVE, and the upper split point of an interval equals an item retained by the sketch, the interval will include that item. If the lower split point equals an item retained by the sketch, the interval will exclude that item.
    
    EXCLUSIVE, and the upper split point of an interval equals an item retained by the sketch, the interval will exclude that item. If the lower split point equals an item retained by the sketch, the interval will include that item.
    
    It is not recommended to include either the minimum or maximum items of the input stream.
    
    searchCrit - the desired search criteria.
    
    Returns:
    
    a PMF array of m+1 probability masses as doubles on the interval [0.0, 1.0].
  - getQuantile
```
public T getQuantile(double rank)
```
    Description copied from interface: QuantilesGenericAPI
    
    This is equivalent to getQuantile(rank, INCLUSIVE)
    
    Specified by:
    
    getQuantile in interface QuantilesGenericAPI<T>
    
    Parameters:
    
    rank - the given normalized rank, a double in the range [0.0, 1.0].
    
    Returns:
    
    the approximate quantile given the normalized rank.
  - getQuantile
```
public T getQuantile(double rank,
                     QuantileSearchCriteria searchCrit)
```
    Description copied from interface: QuantilesGenericAPI
    
    Gets the approximate quantile of the given normalized rank and the given search criterion.
    
    Specified by:
    
    getQuantile in interface QuantilesGenericAPI<T>
    
    Parameters:
    
    rank - the given normalized rank, a double in the range [0.0, 1.0].
    
    searchCrit - If INCLUSIVE, the given rank includes all quantiles ≤ the quantile directly corresponding to the given rank. If EXCLUSIVE, he given rank includes all quantiles < the quantile directly corresponding to the given rank.
    
    Returns:
    
    the approximate quantile given the normalized rank.
    
    See Also:
    
    QuantileSearchCriteria
  - getQuantileLowerBound
```
public T getQuantileLowerBound(double rank)
```
    Description copied from interface: QuantilesGenericAPI
    
    Gets the lower bound of the quantile confidence interval in which the quantile of the given rank exists.
    Although it is possible to estimate the probability that the true quantile exists within the quantile confidence interval specified by the upper and lower quantile bounds, it is not possible to guarantee the width of the quantile confidence interval as an additive or multiplicative percent of the true quantile.
    
    Specified by:
    
    getQuantileLowerBound in interface QuantilesGenericAPI<T>
    
    Parameters:
    
    rank - the given normalized rank
    
    Returns:
    
    the lower bound of the quantile confidence interval in which the quantile of the given rank exists.
  - getQuantileUpperBound
```
public T getQuantileUpperBound(double rank)
```
    Description copied from interface: QuantilesGenericAPI
    
    Gets the upper bound of the quantile confidence interval in which the true quantile of the given rank exists.
    Although it is possible to estimate the probability that the true quantile exists within the quantile confidence interval specified by the upper and lower quantile bounds, it is not possible to guarantee the width of the quantile interval as an additive or multiplicative percent of the true quantile.
    
    Specified by:
    
    getQuantileUpperBound in interface QuantilesGenericAPI<T>
    
    Parameters:
    
    rank - the given normalized rank
    
    Returns:
    
    the upper bound of the quantile confidence interval in which the true quantile of the given rank exists.
  - getQuantiles
```
public T[] getQuantiles(double[] ranks)
```
    Description copied from interface: QuantilesGenericAPI
    
    This is equivalent to getQuantiles(ranks, INCLUSIVE)
    
    Specified by:
    
    getQuantiles in interface QuantilesGenericAPI<T>
    
    Parameters:
    
    ranks - the given array of normalized ranks, each of which must be in the interval [0.0,1.0].
    
    Returns:
    
    an array of quantiles corresponding to the given array of normalized ranks.
  - getQuantiles
```
public T[] getQuantiles(double[] ranks,
                        QuantileSearchCriteria searchCrit)
```
    Description copied from interface: QuantilesGenericAPI
    
    Gets an array of quantiles from the given array of normalized ranks.
    
    Specified by:
    
    getQuantiles in interface QuantilesGenericAPI<T>
    
    Parameters:
    
    ranks - the given array of normalized ranks, each of which must be in the interval [0.0,1.0].
    
    searchCrit - if INCLUSIVE, the given ranks include all quantiles ≤ the quantile directly corresponding to each rank.
    
    Returns:
    
    an array of quantiles corresponding to the given array of normalized ranks.
    
    See Also:
    
    QuantileSearchCriteria
  - getRank
```
public double getRank(T quantile)
```
    Description copied from interface: QuantilesGenericAPI
    
    This is equivalent to getRank(T quantile, INCLUSIVE)
    
    Specified by:
    
    getRank in interface QuantilesGenericAPI<T>
    
    Parameters:
    
    quantile - the given quantile
    
    Returns:
    
    the normalized rank corresponding to the given quantile.
  - getRank
```
public double getRank(T quantile,
                      QuantileSearchCriteria searchCrit)
```
    Description copied from interface: QuantilesGenericAPI
    
    Gets the normalized rank corresponding to the given a quantile.
    
    Specified by:
    
    getRank in interface QuantilesGenericAPI<T>
    
    Parameters:
    
    quantile - the given quantile
    
    searchCrit - if INCLUSIVE the given quantile is included into the rank.
    
    Returns:
    
    the normalized rank corresponding to the given quantile.
    
    See Also:
    
    QuantileSearchCriteria
  - getRankLowerBound
```
public double getRankLowerBound(double rank)
```
    Description copied from interface: QuantilesAPI
    
    Gets the lower bound of the rank confidence interval in which the true rank of the given rank exists.
    
    Specified by:
    
    getRankLowerBound in interface QuantilesAPI
    
    Parameters:
    
    rank - the given normalized rank.
    
    Returns:
    
    the lower bound of the rank confidence interval in which the true rank of the given rank exists.
  - getRankUpperBound
```
public double getRankUpperBound(double rank)
```
    Description copied from interface: QuantilesAPI
    
    Gets the upper bound of the rank confidence interval in which the true rank of the given rank exists.
    
    Specified by:
    
    getRankUpperBound in interface QuantilesAPI
    
    Parameters:
    
    rank - the given normalized rank.
    
    Returns:
    
    the upper bound of the rank confidence interval in which the true rank of the given rank exists.
  - getRanks
```
public double[] getRanks(T[] quantiles)
```
    Description copied from interface: QuantilesGenericAPI
    
    This is equivalent to getRanks(quantiles, INCLUSIVE)
    
    Specified by:
    
    getRanks in interface QuantilesGenericAPI<T>
    
    Parameters:
    
    quantiles - the given array of quantiles
    
    Returns:
    
    an array of normalized ranks corresponding to the given array of quantiles.
  - getRanks
```
public double[] getRanks(T[] quantiles,
                         QuantileSearchCriteria searchCrit)
```
    Description copied from interface: QuantilesGenericAPI
    
    Gets an array of normalized ranks corresponding to the given array of quantiles and the given search criterion.
    
    Specified by:
    
    getRanks in interface QuantilesGenericAPI<T>
    
    Parameters:
    
    quantiles - the given array of quantiles
    
    searchCrit - if INCLUSIVE, the given quantiles include the rank directly corresponding to each quantile.
    
    Returns:
    
    an array of normalized ranks corresponding to the given array of quantiles.
    
    See Also:
    
    QuantileSearchCriteria
  - iterator
```
public QuantilesGenericSketchIterator<T> iterator()
```
    Description copied from interface: QuantilesGenericAPI
    
    Gets the iterator for this sketch, which is not sorted.
    
    Specified by:
    
    iterator in interface QuantilesGenericAPI<T>
    
    Returns:
    
    the iterator for this sketch
  - getK
```
public int getK()
```
    Description copied from interface: QuantilesAPI
    
    Gets the user configured parameter k, which controls the accuracy of the sketch and its memory space usage.
    
    Specified by:
    
    getK in interface QuantilesAPI
    
    Returns:
    
    the user configured parameter k, which controls the accuracy of the sketch and its memory space usage.
  - getN
```
public long getN()
```
    Description copied from interface: QuantilesAPI
    
    Gets the length of the input stream.
    
    Specified by:
    
    getN in interface QuantilesAPI
    
    Returns:
    
    the length of the input stream.
  - getNormalizedRankError
```
public double getNormalizedRankError(boolean pmf)
```
    Gets the approximate rank error of this sketch normalized as a fraction between zero and one.
    
    Parameters:
    
    pmf - if true, returns the "double-sided" normalized rank error for the getPMF() function. Otherwise, it is the "single-sided" normalized rank error for all the other queries.
    
    Returns:
    
    if pmf is true, returns the normalized rank error for the getPMF() function. Otherwise, it is the "single-sided" normalized rank error for all the other queries.
  - getNormalizedRankError
```
public static double getNormalizedRankError(int k,
                                            boolean pmf)
```
    Gets the normalized rank error given k and pmf. Static method version of the getNormalizedRankError(boolean).
    
    Parameters:
    
    k - the configuration parameter
    
    pmf - if true, returns the "double-sided" normalized rank error for the getPMF() function. Otherwise, it is the "single-sided" normalized rank error for all the other queries.
    
    Returns:
    
    if pmf is true, the normalized rank error for the getPMF() function. Otherwise, it is the "single-sided" normalized rank error for all the other queries.
  - getKFromEpsilon
```
public static int getKFromEpsilon(double epsilon,
                                  boolean pmf)
```
    Gets the approximate k to use given epsilon, the normalized rank error.
    
    Parameters:
    
    epsilon - the normalized rank error between zero and one.
    
    pmf - if true, this function returns k assuming the input epsilon is the desired "double-sided" epsilon for the getPMF() function. Otherwise, this function returns k assuming the input epsilon is the desired "single-sided" epsilon for all the other queries.
    
    Returns:
    
    k given epsilon.
  - hasMemory
```
public boolean hasMemory()
```
    Description copied from interface: QuantilesAPI
    
    Returns true if this sketch's data structure is backed by Memory or WritableMemory.
    
    Specified by:
    
    hasMemory in interface QuantilesAPI
    
    Returns:
    
    true if this sketch's data structure is backed by Memory or WritableMemory.
  - isEmpty
```
public boolean isEmpty()
```
    Description copied from interface: QuantilesAPI
    
    Returns true if this sketch is empty.
    
    Specified by:
    
    isEmpty in interface QuantilesAPI
    
    Returns:
    
    true if this sketch is empty.
  - isDirect
```
public boolean isDirect()
```
    Description copied from interface: QuantilesAPI
    
    Returns true if this sketch's data structure is off-heap (a.k.a., Direct or Native memory).
    
    Specified by:
    
    isDirect in interface QuantilesAPI
    
    Returns:
    
    true if this sketch's data structure is off-heap (a.k.a., Direct or Native memory).
  - isEstimationMode
```
public boolean isEstimationMode()
```
    Description copied from interface: QuantilesAPI
    
    Returns true if this sketch is in estimation mode.
    
    Specified by:
    
    isEstimationMode in interface QuantilesAPI
    
    Returns:
    
    true if this sketch is in estimation mode.
  - isReadOnly
```
public boolean isReadOnly()
```
    Description copied from interface: QuantilesAPI
    
    Returns true if this sketch is read only.
    
    Specified by:
    
    isReadOnly in interface QuantilesAPI
    
    Returns:
    
    true if this sketch is read only.
  - reset
```
public void reset()
```
    Description copied from interface: QuantilesAPI
    
    Resets this sketch to the empty state. If the sketch is read only this does nothing.
    The parameter k will not change.
    
    Specified by:
    
    reset in interface QuantilesAPI
  - toByteArray
```
public byte[] toByteArray(ArrayOfItemsSerDe<T> serDe)
```
    Serialize this sketch to a byte array form.
    
    Parameters:
    
    serDe - an instance of ArrayOfItemsSerDe
    
    Returns:
    
    byte array of this sketch
  - toByteArray
```
public byte[] toByteArray(boolean ordered,
                          ArrayOfItemsSerDe<T> serDe)
```
    Serialize this sketch to a byte array form.
    
    Parameters:
    
    ordered - if true the base buffer will be ordered (default == false).
    
    serDe - an instance of ArrayOfItemsSerDe
    
    Returns:
    
    this sketch in a byte array form.
  - toString
```
public String toString()
```
    Description copied from interface: QuantilesAPI
    
    Returns a summary of the key parameters of the sketch.
    
    Specified by:
    
    toString in interface QuantilesAPI
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    a summary of the key parameters of the sketch.
  - toString
```
public String toString(boolean sketchSummary,
                       boolean dataDetail)
```
    Returns summary information about this sketch. Used for debugging.
    
    Parameters:
    
    sketchSummary - if true includes sketch summary
    
    dataDetail - if true includes data detail
    
    Returns:
    
    summary information about the sketch.
  - toString
```
public static String toString(byte[] byteArr)
```
    Returns a human readable string of the preamble of a byte array image of an ItemsSketch.
    
    Parameters:
    
    byteArr - the given byte array
    
    Returns:
    
    a human readable string of the preamble of a byte array image of an ItemsSketch.
  - toString
```
public static String toString(org.apache.datasketches.memory.Memory mem)
```
    Returns a human readable string of the preamble of a Memory image of an ItemsSketch.
    
    Parameters:
    
    mem - the given Memory
    
    Returns:
    
    a human readable string of the preamble of a Memory image of an ItemsSketch.
  - downSample
```
public ItemsSketch<T> downSample(int newK)
```
    From an existing sketch, this creates a new sketch that can have a smaller K. The original sketch is not modified.
    
    Parameters:
    
    newK - the new K that must be smaller than current K. It is required that this.getK() = newK * 2^(nonnegative integer).
    
    Returns:
    
    the new sketch.
  - getNumRetained
```
public int getNumRetained()
```
    Description copied from interface: QuantilesAPI
    
    Gets the number of quantiles retained by the sketch.
    
    Specified by:
    
    getNumRetained in interface QuantilesAPI
    
    Returns:
    
    the number of quantiles retained by the sketch
  - putMemory
```
public void putMemory(org.apache.datasketches.memory.WritableMemory dstMem,
                      ArrayOfItemsSerDe<T> serDe)
```
    Puts the current sketch into the given Memory if there is sufficient space. Otherwise, throws an error.
    
    Parameters:
    
    dstMem - the given memory.
    
    serDe - an instance of ArrayOfItemsSerDe
  - getSortedView
```
public GenericSortedView<T> getSortedView()
```
    Description copied from interface: QuantilesGenericAPI
    
    Gets the sorted view of this sketch
    
    Specified by:
    
    getSortedView in interface QuantilesGenericAPI<T>
    
    Returns:
    
    the sorted view of this sketch
  - update
```
public void update(T item)
```
    Description copied from interface: QuantilesGenericAPI
    
    Updates this sketch with the given item.
    
    Specified by:
    
    update in interface QuantilesGenericAPI<T>
    
    Parameters:
    
    item - from a stream of items. Nulls are ignored.

Class ItemsSketch<T>

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.datasketches.quantilescommon.QuantilesGenericAPI

Field Summary

Fields inherited from interface org.apache.datasketches.quantilescommon.QuantilesAPI

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface org.apache.datasketches.quantilescommon.QuantilesGenericAPI

Field Detail

rand

Method Detail

getInstance

getInstance

getInstance

getCDF

getCDF

getSketchType

getMaxItem

getMinItem

getPartitionBoundaries

getPMF

getPMF

getQuantile

getQuantile

getQuantileLowerBound

getQuantileUpperBound

getQuantiles

getQuantiles

getRank

getRank

getRankLowerBound

getRankUpperBound

getRanks

getRanks

iterator

getK

getN

getNormalizedRankError

getNormalizedRankError

getKFromEpsilon

hasMemory

isEmpty

isDirect

isEstimationMode

isReadOnly

reset

toByteArray

toByteArray

toString

toString

toString

toString

downSample

getNumRetained

putMemory

getSortedView

update