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

Class AOffset

  • All Implemented Interfaces:
    Serializable
    Direct Known Subclasses:
    AOffsetByte, OffsetChar, OffsetEmpty, OffsetSingle, OffsetTwo
    public abstract class AOffset
extends Object
implements Serializable
    Offset list encoder abstract class.

    It is assumed that the input is in sorted order, all values are positive and there are no duplicates.

    The no duplicate is important since 0 values are exploited to encode an offset of max representable value + 1. This gives the ability to encode data, where the offsets are greater than the available highest value that can be represented size.

    See Also:
    Serialized Form

    • Constructor Detail

      • AOffset

        public AOffset()

    • Method Detail

      • getIterator

        public abstract AIterator getIterator()
        Get an iterator of the offsets while also maintaining the data index pointer.
        Returns:
        AIterator that iterate through index and dictionary offset values.

      • getOffsetIterator

        public abstract AOffsetIterator getOffsetIterator()
        Get an OffsetIterator of current offsets not maintaining the data index.
        Returns:
        AIterator that iterator through the delta offsets.

      • getIterator

        public AIterator getIterator​(int row)
        Get an iterator that is pointing at a specific offset.
        Parameters:
        row - The row requested.
        Returns:
        AIterator that iterate through index and dictionary offset values.

      • constructSkipList

        public void constructSkipList()

      • clearSkipList

        public void clearSkipList()

      • cacheIterator

        public void cacheIterator​(AIterator it,
                          int row)
        Cache a iterator in use, note that there is no check for if the iterator is correctly positioned at the given row
        Parameters:
        it - The Iterator to cache
        row - The row index to cache the iterator as.

      • write

        public abstract void write​(DataOutput out)
                    throws IOException
        Write the offsets to disk. If you implement another remember to write the ordinal of the new type to disk as well and add it to the OffsetFactory.
        Parameters:
        out - The output to write to
        Throws:
        IOException - Exception that happens if the IO fails to write.

      • getOffsetToFirst

        public abstract int getOffsetToFirst()
        Get the offset to the first index
        Returns:
        The first index offset

      • getOffsetToLast

        public abstract int getOffsetToLast()
        Get the offset to the last value
        Returns:
        The last values offset

      • getInMemorySize

        public abstract long getInMemorySize()
        Get the in memory size of the Offset object
        Returns:
        In memory size as a long.

      • getExactSizeOnDisk

        public abstract long getExactSizeOnDisk()
        Remember to include the ordinal of the type of offset list.
        Returns:
        the size on disk as a long.

      • getSize

        public abstract int getSize()
        Get the number of contained elements, This method iterate the entire offset list, so it is not constant lookup.
        Returns:
        The number of indexes.

      • preAggregateDenseMap

        public final void preAggregateDenseMap​(DenseBlock db,
                                       double[] preAV,
                                       int rl,
                                       int ru,
                                       int cl,
                                       int cu,
                                       int nVal,
                                       AMapToData data)
        Pre aggregate the specified row and block range from a dense MatrixBlock to prepare for compressed multiplication.
        Parameters:
        db - The DenseBlock to extract values from.
        preAV - The pre aggregate row linearized double array to put the values into.
        rl - The row lower to start from (this is referring to the left matrix of the multiplication)
        ru - The row upper to end at (not inclusive) (this is referring to the left matrix of the multiplication)
        cl - The column lower to start at (this is referring to the right matrix of the multiplication)
        cu - The column upper to end at (not inclusive) (this is referring to the right matrix of the multiplication)
        nVal - The number of distinct values in the PreAV indicating number of columns in the Pre aggregate
        data - The mapping to column positions in the preAV

      • preAggSparseMap

        public final void preAggSparseMap​(SparseBlock sb,
                                  double[] preAV,
                                  int rl,
                                  int ru,
                                  int nVal,
                                  AMapToData data)

      • equals

        public boolean equals​(AOffset b)

      • moveIndex

        public abstract AOffset moveIndex​(int m)
        Move the index start x cells
        Parameters:
        m - The amount to move
        Returns:
        The moved index.

      • getLength

        public abstract int getLength()
        Get the length of the underlying array. This does not reflect the number of contained elements, since some of the elements can be skips.
        Returns:
        The length of the underlying arrays

      • slice

        public AOffset.OffsetSliceInfo slice​(int l,
                                     int u)
        Slice the offsets based on the specified range
        Parameters:
        l - inclusive lower bound
        u - exclusive upper bound
        Returns:
        The slice info containing the new slice.

      • append

        public AOffset append​(AOffset t,
                      int s)
        Append the offsets from that other offset to the offsets in this.
        Parameters:
        t - That offset/
        s - The total length encoded in this offset.
        Returns:
        this offsets followed by thats offsets.

      • appendN

        public AOffset appendN​(AOffsetsGroup[] g,
                       int s)
        Append a list of offsets together in order.
        Parameters:
        g - The offsets to append together (note fist entry is equal to this)
        s - The standard size of each g (except last, but that does not matter)
        Returns:
        The combined offsets.

      • verify

        public void verify​(int size)
        Verify that the contained AOffset is a certain size, and not bigger when iterating though it.
        Parameters:
        size - The max correct size.

      • reverse

        public AOffset reverse​(int numRows)
        Reverse the locations of the offsets such that the inverse offsets are returned. This means that for instance if the current offsets were 1, 3 and 5 in a 5 long list, we return 0, 2 and 4.
        Parameters:
        numRows - The total number of rows to be contained, This should be greater or equal to last.
        Returns:
        The reverse offsets.