Package org.apache.sysds.runtime.matrix.data

Interface LibMatrixCountDistinct

public interface LibMatrixCountDistinct

This class contains various methods for counting the number of distinct values inside a MatrixBlock

Field Summary

Fields

Modifier and Type	Field	Description
static org.apache.commons.logging.Log	LOG
static int	minimumSize	The minimum number NonZero of cells in the input before using approximate techniques for counting number of distinct values.

Method Summary

Static Methods

Modifier and Type	Method	Description
static MatrixBlock	countDistinctValuesFromSketch(CorrMatrixBlock arg0, CountDistinctOperator op)
static CorrMatrixBlock	createSketch(MatrixBlock blkIn, CountDistinctOperator op)
static int	estimateDistinctValues(MatrixBlock in, CountDistinctOperator op)	Public method to count the number of distinct values inside a matrix.
static CorrMatrixBlock	unionSketch(CorrMatrixBlock arg0, CorrMatrixBlock arg1, CountDistinctOperator op)

Field Detail

LOG

static final org.apache.commons.logging.Log LOG

minimumSize

static final int minimumSize

The minimum number NonZero of cells in the input before using approximate techniques for counting number of distinct values.

See Also:

Constant Field Values

Method Detail

estimateDistinctValues

static int estimateDistinctValues(MatrixBlock in,
                                  CountDistinctOperator op)

Public method to count the number of distinct values inside a matrix. Depending on which CountDistinctOperator selected it either gets the absolute number or a estimated value. TODO: Support counting num distinct in rows, or columns axis. TODO: Add support for distributed spark operations TODO: If the MatrixBlock type is CompressedMatrix, simply read the values from the ColGroups.

Parameters:

in - the input matrix to count number distinct values in

op - the selected operator to use

Returns:

the distinct count

countDistinctValuesFromSketch

static MatrixBlock countDistinctValuesFromSketch(CorrMatrixBlock arg0,
                                                 CountDistinctOperator op)

createSketch

static CorrMatrixBlock createSketch(MatrixBlock blkIn,
                                    CountDistinctOperator op)

unionSketch

static CorrMatrixBlock unionSketch(CorrMatrixBlock arg0,
                                   CorrMatrixBlock arg1,
                                   CountDistinctOperator op)