org.apache.sysds.runtime.instructions.gpu.context

## Class CSRPointer

- java.lang.Object
- - org.apache.sysds.runtime.instructions.gpu.context.CSRPointer

-     public class CSRPointer
      extends Object

  Compressed Sparse Row (CSR) format for CUDA Generalized matrix multiply is implemented for CSR format in the cuSparse library among other operations Since we assume that the matrix is stored with zero-based indexing (i.e. CUSPARSE_INDEX_BASE_ZERO), the matrix 1.0 4.0 0.0 0.0 0.0 0.0 2.0 3.0 0.0 0.0 5.0 0.0 0.0 7.0 8.0 0.0 0.0 9.0 0.0 6.0 is stored as val = 1.0 4.0 2.0 3.0 5.0 7.0 8.0 9.0 6.0 rowPtr = 0.0 2.0 4.0 7.0 9.0 colInd = 0.0 1.0 1.0 2.0 0.0 3.0 4.0 2.0 4.0

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `jcuda.Pointer` | `colInd` integer array of nnz values' column indices
    `jcuda.jcusparse.cusparseMatDescr` | `descr` descriptor of matrix, only CUSPARSE_MATRIX_TYPE_GENERAL supported
    `static jcuda.jcusparse.cusparseMatDescr` | `matrixDescriptor`
    `long` | `nnz` Number of non zeroes
    `jcuda.Pointer` | `rowPtr` integer array of start of all rows and end of last row + 1
    `jcuda.Pointer` | `val` double array of non zero values

  - ### Method Summary

    All Methods Static Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `static CSRPointer` | `allocateEmpty(GPUContext gCtx, long nnz2, long rows)` Factory method to allocate an empty CSR Sparse matrix on the GPU
    `static CSRPointer` | `allocateForDgeam(GPUContext gCtx, jcuda.jcusparse.cusparseHandle handle, CSRPointer A, CSRPointer B, int m, int n)` Estimates the number of non zero elements from the results of a sparse cusparseDgeam operation C = a op(A) + b op(B)
    `static CSRPointer` | `allocateForMatrixMultiply(GPUContext gCtx, jcuda.jcusparse.cusparseHandle handle, CSRPointer A, int transA, CSRPointer B, int transB, int m, int n, int k)` Estimates the number of non-zero elements from the result of a sparse matrix multiplication C = A * B and returns the `CSRPointer` to C with the appropriate GPU memory.
    `CSRPointer` | `clone(int rows)`
    `static void` | `copyPtrToHost(CSRPointer src, int rows, long nnz, int[] rowPtr, int[] colInd)` Static method to copy a CSR sparse matrix from Device to host
    `static void` | `copyToDevice(GPUContext gCtx, CSRPointer dest, int rows, long nnz, int[] rowPtr, int[] colInd, double[] values)` Static method to copy a CSR sparse matrix from Host to Device
    `void` | `deallocate()` Calls cudaFree lazily on the allocated `Pointer` instances
    `void` | `deallocate(boolean eager)` Calls cudaFree lazily or eagerly on the allocated `Pointer` instances
    `static long` | `estimateSize(long nnz2, long rows)` Estimate the size of a CSR matrix in GPU memory Size of pointers is not needed and is not added in
    `static jcuda.jcusparse.cusparseMatDescr` | `getDefaultCuSparseMatrixDescriptor()`
    `boolean` | `isUltraSparse(int rows, int cols)` Check for ultra sparsity
    `jcuda.Pointer` | `toColumnMajorDenseMatrix(jcuda.jcusparse.cusparseHandle cusparseHandle, jcuda.jcublas.cublasHandle cublasHandle, int rows, int cols, String instName)` Copies this CSR matrix on the GPU to a dense column-major matrix on the GPU.
    `static int` | `toIntExact(long l)`
    `String` | `toString()`

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

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

- - ### Field Detail

    - #### matrixDescriptor

          public static jcuda.jcusparse.cusparseMatDescr matrixDescriptor

    - #### nnz

          public long nnz

      Number of non zeroes

    - #### val

          public jcuda.Pointer val

      double array of non zero values

    - #### rowPtr

          public jcuda.Pointer rowPtr

      integer array of start of all rows and end of last row + 1

    - #### colInd

          public jcuda.Pointer colInd

      integer array of nnz values' column indices

    - #### descr

          public jcuda.jcusparse.cusparseMatDescr descr

      descriptor of matrix, only CUSPARSE_MATRIX_TYPE_GENERAL supported

  - ### Method Detail

    - #### toIntExact

          public static int toIntExact(long l)

    - #### getDefaultCuSparseMatrixDescriptor

          public static jcuda.jcusparse.cusparseMatDescr getDefaultCuSparseMatrixDescriptor()

      Returns:
        Singleton default matrix descriptor object (set with CUSPARSE_MATRIX_TYPE_GENERAL, CUSPARSE_INDEX_BASE_ZERO)

    - #### estimateSize

          public static long estimateSize(long nnz2,
                                          long rows)

      Estimate the size of a CSR matrix in GPU memory Size of pointers is not needed and is not added in
      Parameters:
        `nnz2` - number of non zeroes
        `rows` - number of rows
      Returns:
        size estimate

    - #### copyToDevice

          public static void copyToDevice(GPUContext gCtx,
                                          CSRPointer dest,
                                          int rows,
                                          long nnz,
                                          int[] rowPtr,
                                          int[] colInd,
                                          double[] values)

      Static method to copy a CSR sparse matrix from Host to Device
      Parameters:
        `gCtx` - GPUContext
        `dest` - [input] destination location (on GPU)
        `rows` - number of rows
        `nnz` - number of non-zeroes
        `rowPtr` - integer array of row pointers
        `colInd` - integer array of column indices
        `values` - double array of non zero values

    - #### copyPtrToHost

          public static void copyPtrToHost(CSRPointer src,
                                           int rows,
                                           long nnz,
                                           int[] rowPtr,
                                           int[] colInd)

      Static method to copy a CSR sparse matrix from Device to host
      Parameters:
        `src` - [input] source location (on GPU)
        `rows` - [input] number of rows
        `nnz` - [input] number of non-zeroes
        `rowPtr` - [output] pre-allocated integer array of row pointers of size (rows+1)
        `colInd` - [output] pre-allocated integer array of column indices of size nnz

    - #### allocateForDgeam

          public static CSRPointer allocateForDgeam(GPUContext gCtx,
                                                    jcuda.jcusparse.cusparseHandle handle,
                                                    CSRPointer A,
                                                    CSRPointer B,
                                                    int m,
                                                    int n)

      Estimates the number of non zero elements from the results of a sparse cusparseDgeam operation C = a op(A) + b op(B)
      Parameters:
        `gCtx` - a valid `GPUContext`
        `handle` - a valid `cusparseHandle`
        `A` - Sparse Matrix A on GPU
        `B` - Sparse Matrix B on GPU
        `m` - Rows in A
        `n` - Columns in Bs
      Returns:
        CSR (compressed sparse row) pointer

    - #### allocateForMatrixMultiply

          public static CSRPointer allocateForMatrixMultiply(GPUContext gCtx,
                                                             jcuda.jcusparse.cusparseHandle handle,
                                                             CSRPointer A,
                                                             int transA,
                                                             CSRPointer B,
                                                             int transB,
                                                             int m,
                                                             int n,
                                                             int k)

      Estimates the number of non-zero elements from the result of a sparse matrix multiplication C = A * B and returns the `CSRPointer` to C with the appropriate GPU memory.
      Parameters:
        `gCtx` - a valid `GPUContext`
        `handle` - a valid `cusparseHandle`
        `A` - Sparse Matrix A on GPU
        `transA` - 'T' if A is to be transposed, 'N' otherwise
        `B` - Sparse Matrix B on GPU
        `transB` - 'T' if B is to be transposed, 'N' otherwise
        `m` - Rows in A
        `n` - Columns in B
        `k` - Columns in A / Rows in B
      Returns:
        a `CSRPointer` instance that encapsulates the CSR matrix on GPU

    - #### allocateEmpty

          public static CSRPointer allocateEmpty(GPUContext gCtx,
                                                 long nnz2,
                                                 long rows)

      Factory method to allocate an empty CSR Sparse matrix on the GPU
      Parameters:
        `gCtx` - a valid `GPUContext`
        `nnz2` - number of non-zeroes
        `rows` - number of rows
      Returns:
        a `CSRPointer` instance that encapsulates the CSR matrix on GPU

    - #### clone

          public CSRPointer clone(int rows)

    - #### isUltraSparse

          public boolean isUltraSparse(int rows,
                                       int cols)

      Check for ultra sparsity
      Parameters:
        `rows` - number of rows
        `cols` - number of columns
      Returns:
        true if ultra sparse

    - #### toColumnMajorDenseMatrix

          public jcuda.Pointer toColumnMajorDenseMatrix(jcuda.jcusparse.cusparseHandle cusparseHandle,
                                                        jcuda.jcublas.cublasHandle cublasHandle,
                                                        int rows,
                                                        int cols,
                                                        String instName)

      Copies this CSR matrix on the GPU to a dense column-major matrix on the GPU. This is a temporary matrix for operations such as cusparseDcsrmv. Since the allocated matrix is temporary, bookkeeping is not updated. The caller is responsible for calling "free" on the returned Pointer object
      Parameters:
        `cusparseHandle` - a valid `cusparseHandle`
        `cublasHandle` - a valid `cublasHandle`
        `rows` - number of rows in this CSR matrix
        `cols` - number of columns in this CSR matrix
        `instName` - name of the invoking instruction to record`Statistics`.
      Returns:
        A `Pointer` to the allocated dense matrix (in column-major format)

    - #### deallocate

          public void deallocate()

      Calls cudaFree lazily on the allocated `Pointer` instances

    - #### deallocate

          public void deallocate(boolean eager)

      Calls cudaFree lazily or eagerly on the allocated `Pointer` instances
      Parameters:
        `eager` - whether to do eager or lazy cudaFrees

    - #### toString

          public String toString()

      Overrides:
        `toString` in class `Object`

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