org.apache.sysds.runtime.compress.readers

## Class ReaderColumnSelectionSparse

- java.lang.Object
- - org.apache.sysds.runtime.compress.readers.ReaderColumnSelection
  - - org.apache.sysds.runtime.compress.readers.ReaderColumnSelectionSparse

-     public class ReaderColumnSelectionSparse
      extends ReaderColumnSelection

  Used to extract the values at certain indexes from each row in a sparse matrix Keeps returning all-zeros arrays until reaching the last possible index. The current compression algorithm treats the zero-value in a sparse matrix like any other value.

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `ReaderColumnSelectionSparse(MatrixBlock data, int[] colIndexes)` Reader of sparse matrix blocks for compression.

  - ### Method Summary

    - ### Methods inherited from class org.apache.sysds.runtime.compress.readers.ReaderColumnSelection

      `createCompressedReader, createReader, getCurrentRowIndex, nextRow`

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

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

- - ### Constructor Detail

    - #### ReaderColumnSelectionSparse

          public ReaderColumnSelectionSparse(MatrixBlock data,
                                             int[] colIndexes)

      Reader of sparse matrix blocks for compression. This reader should not be used if the input data is not sparse
      Parameters:
        `data` - The transposed and sparse matrix
        `colIndexes` - The column indexes to combine

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