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* Contents: Native middle-level C interface to LAPACK function dorbdb
* Author: Intel Corporation
*****************************************************************************/

#include "lapacke_utils.h"

lapack_int LAPACKE_dorbdb_work( int matrix_layout, char trans, char signs,
                                lapack_int m, lapack_int p, lapack_int q,
                                double* x11, lapack_int ldx11, double* x12,
                                lapack_int ldx12, double* x21, lapack_int ldx21,
                                double* x22, lapack_int ldx22, double* theta,
                                double* phi, double* taup1, double* taup2,
                                double* tauq1, double* tauq2, double* work,
                                lapack_int lwork )
{
    lapack_int info = 0;
    /* LAPACK function works with matrices in both layouts. It is supported
     * through TRANS parameter. So all conversion between layouts can be
     * completed in LAPACK function. See the table below which describes how
     * every LAPACKE call is forwarded to corresponding LAPACK call.
     *
     *   matrix_layout    | trans_LAPACKE | -> trans_LAPACK
     *                    |   (trans)     |       (ltrans)
     *   -----------------+---------------+----------------
     *   LAPACK_COL_MAJOR |     'N'       | ->     'N'
     *   LAPACK_COL_MAJOR |     'T'       | ->     'T'
     *   LAPACK_ROW_MAJOR |     'N'       | ->     'T'
     *   LAPACK_ROW_MAJOR |     'T'       | ->     'T'
     *       (note that for row major layout trans parameter is ignored)
     */
    if( matrix_layout == LAPACK_COL_MAJOR ||
        matrix_layout == LAPACK_ROW_MAJOR ) {
        char ltrans;
        if( !LAPACKE_lsame( trans, 't' ) && matrix_layout == LAPACK_COL_MAJOR ) {
            ltrans = 'n';
        } else {
            ltrans = 't';
        }
        /* Call LAPACK function and adjust info */
        LAPACK_dorbdb( &ltrans, &signs, &m, &p, &q, x11, &ldx11, x12, &ldx12,
                       x21, &ldx21, x22, &ldx22, theta, phi, taup1, taup2,
                       tauq1, tauq2, work, &lwork, &info );
        if( info < 0 ) {
            info = info - 1;
        }
    } else {
        info = -1;
        LAPACKE_xerbla( "LAPACKE_dorbdb_work", info );
    }
    return info;
}
