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

## Class ColGroupSDCSingle

- java.lang.Object
- - org.apache.sysds.runtime.compress.colgroup.AColGroup
  - - org.apache.sysds.runtime.compress.colgroup.AColGroupCompressed
    - - org.apache.sysds.runtime.compress.colgroup.AColGroupValue
      - - org.apache.sysds.runtime.compress.colgroup.AMorphingMMColGroup
        - - org.apache.sysds.runtime.compress.colgroup.ColGroupSDCSingle

- All Implemented Interfaces:
    `Serializable`, `Cloneable`

      public class ColGroupSDCSingle
      extends AMorphingMMColGroup

  Column group that sparsely encodes the dictionary values. The idea is that all values is encoded with indexes except the most common one. the most common one can be inferred by not being included in the indexes. If the values are very sparse then the most common one is zero. This column group is handy in cases where sparse unsafe operations is executed on very sparse columns. Then the zeros would be materialized in the group without any overhead.
  See Also:
    Serialized Form

- - ### Nested Class Summary

    - ### Nested classes/interfaces inherited from class org.apache.sysds.runtime.compress.colgroup.AColGroup

      `AColGroup.CompressionType`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `AColGroup` | `binaryRowOpLeft​(BinaryOperator op, double[] v, boolean isRowSafe)` | Perform a binary row operation.
    `AColGroup` | `binaryRowOpRight​(BinaryOperator op, double[] v, boolean isRowSafe)` | Perform a binary row operation.
    `CM_COV_Object` | `centralMoment​(CMOperator op, int nRows)` | Central Moment instruction executed on a column group.
    `void` | `computeColSums​(double[] c, int nRows)` | Compute the column sum
    `boolean` | `containsValue​(double pattern)` | Detect if the column group contains a specific value.
    `long` | `estimateInMemorySize()` | Get the upper bound estimate of in memory allocation for the column group.
    `AColGroup` | `extractCommon​(double[] constV)` |
    `org.apache.sysds.runtime.compress.colgroup.AColGroup.ColGroupType` | `getColGroupType()` |
    `AColGroup.CompressionType` | `getCompType()` | Obtain the compression type.
    `double` | `getCost​(ComputationCostEstimator e, int nRows)` | Get the computation cost associated with this column group.
    `int[]` | `getCounts​(int[] counts)` |
    `ADictionary` | `getDictionary()` |
    `long` | `getExactSizeOnDisk()` | Returns the exact serialized size of column group.
    `double` | `getIdx​(int r, int colIdx)` | Get the value at a colGroup specific row/column index position.
    `long` | `getNumberNonZeros​(int nRows)` | Get the number of nonZeros contained in this column group.
    `void` | `readFields​(DataInput in)` | Deserialize column group from data input.
    `AColGroup` | `replace​(double pattern, double replace)` | Make a copy of the column group values, and replace all values that match pattern with replacement value.
    `AColGroup` | `rexpandCols​(int max, boolean ignore, boolean cast, int nRows)` | Expand the column group to multiple columns.
    `AColGroup` | `scalarOperation​(ScalarOperator op)` | Perform the specified scalar operation directly on the compressed column group, without decompressing individual cells if possible.
    `String` | `toString()` |
    `AColGroup` | `unaryOperation​(UnaryOperator op)` |
    `void` | `write​(DataOutput out)` | Serializes column group to data output.

    - ### Methods inherited from class org.apache.sysds.runtime.compress.colgroup.AMorphingMMColGroup

      `leftMultByAColGroup, leftMultByMatrixNoPreAgg, tsmmAColGroup`

    - ### Methods inherited from class org.apache.sysds.runtime.compress.colgroup.AColGroupValue

      `copy, decompressToDenseBlock, decompressToSparseBlock, forceMatrixBlockDictionary, getCachedCounts, getCounts, getNumValues, rightMultByMatrix`

    - ### Methods inherited from class org.apache.sysds.runtime.compress.colgroup.AColGroupCompressed

      `getMax, getMin, preAggRows, tsmm, unaryAggregateOperations, unaryAggregateOperations`

    - ### Methods inherited from class org.apache.sysds.runtime.compress.colgroup.AColGroup

      `colSum, decompressToDenseBlock, decompressToSparseBlock, get, getColIndices, getNumCols, shiftColIndices, sliceColumn, sliceColumns`

    - ### Methods inherited from class java.lang.Object

      `equals, getClass, hashCode, notify, notifyAll, wait, wait, wait`

- - ### Method Detail

    - #### 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.

    - #### getColGroupType

          public org.apache.sysds.runtime.compress.colgroup.AColGroup.ColGroupType getColGroupType()

    - #### 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

    - #### getDictionary

          public ADictionary getDictionary()

      Overrides:
        `getDictionary` in class `AColGroupValue`

    - #### computeColSums

          public void computeColSums​(double[] c,
                                     int nRows)

      Description copied from class: `AColGroup`
      Compute the column sum
      Overrides:
        `computeColSums` in class `AColGroupValue`
      Parameters:
        `c` - The array to add the column sum to.
        `nRows` - The number of rows in the column group.

    - #### getCounts

          public int[] getCounts​(int[] counts)

      Specified by:
        `getCounts` in class `AColGroupValue`

    - #### 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.

    - #### 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)

      Specified by:
        `unaryOperation` in class `AColGroup`

    - #### 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, should be same length as dictionary length.
        `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, should be same length as dictionary length.
        `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.

    - #### write

          public void write​(DataOutput out)
                     throws IOException

      Description copied from class: `AColGroup`
      Serializes column group to data output.
      Overrides:
        `write` in class `AColGroupValue`
      Parameters:
        `out` - data output
      Throws:
        `IOException` - if IOException occurs

    - #### readFields

          public void readFields​(DataInput in)
                          throws IOException

      Description copied from class: `AColGroup`
      Deserialize column group from data input.
      Overrides:
        `readFields` in class `AColGroupValue`
      Parameters:
        `in` - data input
      Throws:
        `IOException` - if IOException occurs

    - #### 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 `AColGroupValue`
      Returns:
        exact serialized size for column group

    - #### replace

          public AColGroup replace​(double pattern,
                                   double replace)

      Description copied from class: `AColGroup`
      Make a copy of the column group values, and replace all values that match pattern with replacement value.
      Overrides:
        `replace` in class `AColGroupValue`
      Parameters:
        `pattern` - The value to look for
        `replace` - The value to replace the other value with
      Returns:
        A new Column Group, reusing the index structure but with new values.

    - #### extractCommon

          public AColGroup extractCommon​(double[] constV)

      Specified by:
        `extractCommon` in class `AMorphingMMColGroup`

    - #### getNumberNonZeros

          public long getNumberNonZeros​(int nRows)

      Description copied from class: `AColGroup`
      Get the number of nonZeros contained in this column group.
      Overrides:
        `getNumberNonZeros` in class `AColGroupValue`
      Parameters:
        `nRows` - The number of rows in the column group, this is used for groups that does not contain information about how many rows they have.
      Returns:
        The nnz.

    - #### centralMoment

          public CM_COV_Object centralMoment​(CMOperator op,
                                             int nRows)

      Description copied from class: `AColGroup`
      Central Moment instruction executed on a column group.
      Overrides:
        `centralMoment` in class `AColGroupValue`
      Parameters:
        `op` - The Operator to use.
        `nRows` - The number of rows contained in the ColumnGroup.
      Returns:
        A Central Moment object.

    - #### rexpandCols

          public AColGroup rexpandCols​(int max,
                                       boolean ignore,
                                       boolean cast,
                                       int nRows)

      Description copied from class: `AColGroup`
      Expand the column group to multiple columns. (one hot encode the column group)
      Overrides:
        `rexpandCols` in class `AColGroupValue`
      Parameters:
        `max` - The number of columns to expand to and cutoff values at.
        `ignore` - If zero and negative values should be ignored.
        `cast` - If the double values contained should be cast to whole numbers.
        `nRows` - The number of rows in the column group.
      Returns:
        A new column group containing max number of columns.

    - #### 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

    - #### containsValue

          public boolean containsValue​(double pattern)

      Description copied from class: `AColGroup`
      Detect if the column group contains a specific value.
      Overrides:
        `containsValue` in class `AColGroupValue`
      Parameters:
        `pattern` - The value to look for.
      Returns:
        boolean saying true if the value is contained.

    - #### toString

          public String toString()

      Overrides:
        `toString` in class `AColGroupValue`