TheRock/rocm-libraries/projects/hipsparse/library/include/internal/conversion/hipsparse_csr2coo.h

/*! \file */
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#ifndef HIPSPARSE_CSR2COO_H
#define HIPSPARSE_CSR2COO_H

#ifdef __cplusplus
extern "C" {
#endif

/*! \ingroup conv_module
*  \brief Convert a sparse CSR matrix into a sparse COO matrix.
*
*  \details
*  \p hipsparseXcsr2coo converts the CSR array containing the row offsets that point
*  to the start of every row into a COO array of row indices. All arrays are assumed
*  to be allocated by the user prior to calling \p hipsparseXcsr2coo.
*
*  For example, given the CSR row pointer array (assuming zero index base):
*  \f[
*    \begin{align}
*    \text{csrRowPtr} &= \begin{bmatrix} 0 & 1 & 3 & 4 \end{bmatrix}
*    \end{align}
*  \f]
*
*  Calling \p hipsparseXcsr2coo results in the COO row indices array:
*  \f[
*    \begin{align}
*    \text{cooRowInd} &= \begin{bmatrix} 0 & 1 & 1 & 2 \end{bmatrix}
*    \end{align}
*  \f]
*
*  \note
*  This function can also be used to convert a CSC array containing the column offsets into a COO
*  array of column indices.
*
*  \note
*  This function is non-blocking and executed asynchronously with respect to the host.
*  It can return before the actual computation has finished.
*
*  @param[in]
*  handle      handle to the hipSPARSE library context queue.
*  @param[in]
*  csrRowPtr   array of \p m+1 elements that point to the start of every row
*              of the sparse CSR matrix.
*  @param[in]
*  nnz         number of non-zero entries of the sparse CSR matrix. Must be non-negative.
*  @param[in]
*  m           number of rows of the sparse CSR matrix. Must be non-negative.
*  @param[out]
*  cooRowInd   array of \p nnz elements containing the row indices of the sparse COO
*              matrix.
*  @param[in]
*  idxBase     index base. \ref HIPSPARSE_INDEX_BASE_ZERO for zero-based indexing or
*              \ref HIPSPARSE_INDEX_BASE_ONE for one-based indexing.
*
*  \retval HIPSPARSE_STATUS_SUCCESS the operation completed successfully.
*  \retval HIPSPARSE_STATUS_NOT_INITIALIZED \p handle is not initialized.
*  \retval HIPSPARSE_STATUS_INVALID_VALUE \p handle is nullptr, \p m or, \p nnz is negative,
*          \p csrRowPtr or \p cooRowInd is nullptr when \p nnz is greater than zero, or
*          \p idxBase is neither \ref HIPSPARSE_INDEX_BASE_ZERO nor \ref HIPSPARSE_INDEX_BASE_ONE.
*  \retval HIPSPARSE_STATUS_ARCH_MISMATCH the device is not supported.
*/
HIPSPARSE_EXPORT
hipsparseStatus_t hipsparseXcsr2coo(hipsparseHandle_t    handle,
                                    const int*           csrRowPtr,
                                    int                  nnz,
                                    int                  m,
                                    int*                 cooRowInd,
                                    hipsparseIndexBase_t idxBase);

#ifdef __cplusplus
}
#endif

#endif /* HIPSPARSE_CSR2COO_H */