Package org.apache.sysds.runtime.compress.colgroup

Class ColGroupDDCLZW

java.lang.Object
org.apache.sysds.runtime.compress.colgroup.AColGroup
org.apache.sysds.runtime.compress.colgroup.AColGroupCompressed
org.apache.sysds.runtime.compress.colgroup.ADictBasedColGroup
org.apache.sysds.runtime.compress.colgroup.AColGroupValue
org.apache.sysds.runtime.compress.colgroup.APreAgg
org.apache.sysds.runtime.compress.colgroup.ColGroupDDCLZW
All Implemented Interfaces:
Serializable, IContainADictionary, IMapToDataGroup
public class ColGroupDDCLZW extends APreAgg implements IMapToDataGroup
Class to encapsulate information about a column group that is encoded with dense dictionary encoding (DDC) whose mapping vector is additionally lzw compressed. Idea: - DDCLZW stores the mapping vector exclusively in compressed form. - No persistent MapToData cache is maintained. - Sequential operations decode on-the-fly, while operations requiring random access explicitly materialize and fall back to DDC.
See Also:

  • Method Details

    • create

      public static AColGroup create(IColIndex colIndexes, IDictionary dict, AMapToData data, int[] cachedCounts)

    • convertToDDC

      public AColGroup convertToDDC()
      Converts the current ColGroupDDCLZW instance to a ColGroupDDC instance. The method decompresses the LZW-compressed data of this instance, reconstructs the mapping to the decompressed data, and creates a new ColGroupDDC instance with the decompressed mapping, dictionary, and column indexes of this instance.
      Returns:
      an AColGroup instance representing the decoded ColGroup in DDC format

    • read

      public static ColGroupDDCLZW read(DataInput in) throws IOException
      Throws:
      IOException

    • write

      public void write(DataOutput out) throws IOException
      Overrides:
      write in class ADictBasedColGroup
      Throws:
      IOException

    • getIdx

      public double getIdx(int r, int colIdx)
      Description copied from class: AColGroup
      Get the value at a colGroup specific row/column index position.
      Specified by:
      getIdx in class AColGroup
      Parameters:
      r - row
      colIdx - column index in the _colIndexes.
      Returns:
      value at the row/column index position

    • getCompType

      public AColGroup.CompressionType getCompType()
      Description copied from class: AColGroup
      Obtain the compression type.
      Specified by:
      getCompType in class AColGroup
      Returns:
      How the elements of the column group are compressed.

    • containsValue

      public boolean containsValue(double pattern)
      Description copied from class: AColGroup
      Detect if the column group contains a specific value.
      Specified by:
      containsValue in class AColGroup
      Parameters:
      pattern - The value to look for.
      Returns:
      boolean saying true if the value is contained.

    • getCost

      public double getCost(ComputationCostEstimator e, int nRows)
      Description copied from class: AColGroup
      Get the computation cost associated with this column group.
      Specified by:
      getCost in class AColGroup
      Parameters:
      e - The computation cost estimator
      nRows - the number of rows in the column group
      Returns:
      The cost of this column group

    • getCompressionScheme

      public ICLAScheme getCompressionScheme()
      Description copied from class: AColGroup
      Get the compression scheme for this column group to enable compression of other data.
      Specified by:
      getCompressionScheme in class AColGroup
      Returns:
      The compression scheme of this column group

    • estimateInMemorySize

      public long estimateInMemorySize()
      Description copied from class: AColGroup
      Get the upper bound estimate of in memory allocation for the column group.
      Overrides:
      estimateInMemorySize in class AColGroupValue
      Returns:
      an upper bound on the number of bytes used to store this ColGroup in memory.

    • getExactSizeOnDisk

      public long getExactSizeOnDisk()
      Description copied from class: AColGroup
      Returns the exact serialized size of column group. This can be used for example for buffer preallocation.
      Overrides:
      getExactSizeOnDisk in class ADictBasedColGroup
      Returns:
      exact serialized size for column group

    • getMapToData

      public AMapToData getMapToData()
      Specified by:
      getMapToData in interface IMapToDataGroup

    • sameIndexStructure

      public boolean sameIndexStructure(AColGroupCompressed that)
      Specified by:
      sameIndexStructure in class AColGroupCompressed

    • sliceRows

      public AColGroup sliceRows(int rl, int ru)
      Description copied from class: AColGroup
      Slice range of rows out of the column group and return a new column group only containing the row segment. Note that this slice should maintain pointers back to the original dictionaries and only modify index structures.
      Specified by:
      sliceRows in class AColGroup
      Parameters:
      rl - The row to start at
      ru - The row to end at (not included)
      Returns:
      A new column group containing the specified row range.

    • leftMultByMatrixNoPreAgg

      public void leftMultByMatrixNoPreAgg(MatrixBlock matrix, MatrixBlock result, int rl, int ru, int cl, int cu)
      Description copied from class: AColGroup
      Left multiply with this column group.
      Specified by:
      leftMultByMatrixNoPreAgg in class AColGroup
      Parameters:
      matrix - The matrix to multiply with on the left
      result - The result to output the values into, always dense for the purpose of the column groups parallelizing
      rl - The row to begin the multiplication from on the lhs matrix
      ru - The row to end the multiplication at on the lhs matrix
      cl - The column to begin the multiplication from on the lhs matrix
      cu - The column to end the multiplication at on the lhs matrix

    • scalarOperation

      public AColGroup scalarOperation(ScalarOperator op)
      Description copied from class: AColGroup
      Perform the specified scalar operation directly on the compressed column group, without decompressing individual cells if possible.
      Specified by:
      scalarOperation in class AColGroup
      Parameters:
      op - operation to perform
      Returns:
      version of this column group with the operation applied

    • unaryOperation

      public AColGroup unaryOperation(UnaryOperator op)
      Description copied from class: AColGroup
      Perform unary operation on the column group and return a new column group
      Specified by:
      unaryOperation in class AColGroup
      Parameters:
      op - The operation to perform
      Returns:
      The new column group

    • binaryRowOpLeft

      public AColGroup binaryRowOpLeft(BinaryOperator op, double[] v, boolean isRowSafe)
      Description copied from class: AColGroup
      Perform a binary row operation.
      Specified by:
      binaryRowOpLeft in class AColGroup
      Parameters:
      op - The operation to execute
      v - The vector of values to apply the values contained should be at least the length of the highest value in the column index
      isRowSafe - True if the binary op is applied to an entire zero row and all results are zero
      Returns:
      A updated column group with the new values.

    • binaryRowOpRight

      public AColGroup binaryRowOpRight(BinaryOperator op, double[] v, boolean isRowSafe)
      Description copied from class: AColGroup
      Perform a binary row operation.
      Specified by:
      binaryRowOpRight in class AColGroup
      Parameters:
      op - The operation to execute
      v - The vector of values to apply the values contained should be at least the length of the highest value in the column index
      isRowSafe - True if the binary op is applied to an entire zero row and all results are zero
      Returns:
      A updated column group with the new values.

    • append

      public AColGroup append(AColGroup g)
      Description copied from class: AColGroup
      Append the other column group to this column group. This method tries to combine them to return a new column group containing both. In some cases it is possible in reasonable time, in others it is not. The result is first this column group followed by the other column group in higher row values. If it is not possible or very inefficient null is returned.
      Specified by:
      append in class AColGroup
      Parameters:
      g - The other column group
      Returns:
      A combined column group or null

    • recompress

      public AColGroup recompress()
      Description copied from class: AColGroup
      Recompress this column group into a new column group.
      Specified by:
      recompress in class AColGroup
      Returns:
      A new or the same column group depending on optimization goal.

    • getCompressionInfo

      public CompressedSizeInfoColGroup getCompressionInfo(int nRow)
      Description copied from class: AColGroup
      Get the compression info for this column group.
      Specified by:
      getCompressionInfo in class AColGroup
      Parameters:
      nRow - The number of rows in this column group.
      Returns:
      The compression info for this group.

    • sparseSelection

      public void sparseSelection(MatrixBlock selection, ColGroupUtils.P[] points, MatrixBlock ret, int rl, int ru)

    • splitReshape

      public AColGroup[] splitReshape(int multiplier, int nRow, int nColOrg)
      Description copied from class: AColGroup
      This method returns a list of column groups that are naive splits of this column group as if it is reshaped. This means the column groups rows are split into x number of other column groups where x is the multiplier. The indexes are assigned round robbin to each of the output groups, meaning the first index is assigned. If for instance the 4. column group is split by a 2 multiplier and there was 5 columns in total originally. The output becomes 2 column groups at column index 4 and one at 9. If possible the split column groups should reuse pointers back to the original dictionaries!
      Specified by:
      splitReshape in class AColGroup
      Parameters:
      multiplier - The number of column groups to split into
      nRow - The number of rows in this column group in case the underlying column group does not know
      nColOrg - The number of overall columns in the host CompressedMatrixBlock.
      Returns:
      a list of split column groups

    • preAggregateDense

      public void preAggregateDense(MatrixBlock m, double[] preAgg, int rl, int ru, int cl, int cu)
      Description copied from class: APreAgg
      Pre aggregate a dense matrix block into a pre aggregate target (first step of left matrix multiplication)
      Specified by:
      preAggregateDense in class APreAgg
      Parameters:
      m - The matrix to preAggregate
      preAgg - The preAggregate target
      rl - Row lower on the left side matrix
      ru - Row upper on the left side matrix
      cl - Column lower on the left side matrix (or row lower in the column group)
      cu - Column upper on the left side matrix (or row upper in the column group)

    • preAggregateSparse

      public void preAggregateSparse(SparseBlock sb, double[] preAgg, int rl, int ru, int cl, int cu)
      Specified by:
      preAggregateSparse in class APreAgg

    • leftMMIdentityPreAggregateDense

      public void leftMMIdentityPreAggregateDense(MatrixBlock that, MatrixBlock ret, int rl, int ru, int cl, int cu)
      Specified by:
      leftMMIdentityPreAggregateDense in class APreAgg

    • removeEmptyRows

      public AColGroup removeEmptyRows(boolean[] selectV, int rOut)
      Description copied from class: AColGroup
      Return a new column group containing only the selected rows in the given boolean vector. Whenever possible only modify the index structure, not the dictionary of the column groups.
      Specified by:
      removeEmptyRows in class AColGroup
      Parameters:
      selectV - The selection vector
      rOut - The number of rows in the output
      Returns:
      The new column group

    • sort

      public AColGroup sort()
      Description copied from class: AColGroup
      Sort the values of the column group according to double comparison operations and return as another compressed group. This sorting assumes that the column group is sorted independently of everything else.
      Specified by:
      sort in class AColGroup
      Returns:
      The sorted group