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

#include "lapacke_utils.h"

lapack_int LAPACKE_sgesdd_work( int matrix_layout, char jobz, lapack_int m,
                                lapack_int n, float* a, lapack_int lda,
                                float* s, float* u, lapack_int ldu, float* vt,
                                lapack_int ldvt, float* work, lapack_int lwork,
                                lapack_int* iwork )
{
    lapack_int info = 0;
    if( matrix_layout == LAPACK_COL_MAJOR ) {
        /* Call LAPACK function and adjust info */
        LAPACK_sgesdd( &jobz, &m, &n, a, &lda, s, u, &ldu, vt, &ldvt, work,
                       &lwork, iwork, &info );
        if( info < 0 ) {
            info = info - 1;
        }
    } else if( matrix_layout == LAPACK_ROW_MAJOR ) {
        lapack_int nrows_u = ( LAPACKE_lsame( jobz, 'a' ) ||
                             LAPACKE_lsame( jobz, 's' ) ||
                             ( LAPACKE_lsame( jobz, 'o' ) && m<n) ) ? m : 1;
        lapack_int ncols_u = ( LAPACKE_lsame( jobz, 'a' ) ||
                             ( LAPACKE_lsame( jobz, 'o' ) && m<n) ) ? m :
                             ( LAPACKE_lsame( jobz, 's' ) ? MIN(m,n) : 1);
        lapack_int nrows_vt = ( LAPACKE_lsame( jobz, 'a' ) ||
                              ( LAPACKE_lsame( jobz, 'o' ) && m>=n) ) ? n :
                              ( LAPACKE_lsame( jobz, 's' ) ? MIN(m,n) : 1);
        lapack_int lda_t = MAX(1,m);
        lapack_int ldu_t = MAX(1,nrows_u);
        lapack_int ldvt_t = MAX(1,nrows_vt);
        float* a_t = NULL;
        float* u_t = NULL;
        float* vt_t = NULL;
        /* Check leading dimension(s) */
        if( lda < n ) {
            info = -6;
            LAPACKE_xerbla( "LAPACKE_sgesdd_work", info );
            return info;
        }
        if( ldu < ncols_u ) {
            info = -9;
            LAPACKE_xerbla( "LAPACKE_sgesdd_work", info );
            return info;
        }
        if( ldvt < n ) {
            info = -11;
            LAPACKE_xerbla( "LAPACKE_sgesdd_work", info );
            return info;
        }
        /* Query optimal working array(s) size if requested */
        if( lwork == -1 ) {
            LAPACK_sgesdd( &jobz, &m, &n, a, &lda_t, s, u, &ldu_t, vt, &ldvt_t,
                           work, &lwork, iwork, &info );
            return (info < 0) ? (info - 1) : info;
        }
        /* Allocate memory for temporary array(s) */
        a_t = (float*)LAPACKE_malloc( sizeof(float) * lda_t * MAX(1,n) );
        if( a_t == NULL ) {
            info = LAPACK_TRANSPOSE_MEMORY_ERROR;
            goto exit_level_0;
        }
        if( LAPACKE_lsame( jobz, 'a' ) || LAPACKE_lsame( jobz, 's' ) ||
            ( LAPACKE_lsame( jobz, 'o' ) && (m<n) ) ) {
            u_t = (float*)
                LAPACKE_malloc( sizeof(float) * ldu_t * MAX(1,ncols_u) );
            if( u_t == NULL ) {
                info = LAPACK_TRANSPOSE_MEMORY_ERROR;
                goto exit_level_1;
            }
        }
        if( LAPACKE_lsame( jobz, 'a' ) || LAPACKE_lsame( jobz, 's' ) ||
            ( LAPACKE_lsame( jobz, 'o' ) && (m>=n) ) ) {
            vt_t = (float*)LAPACKE_malloc( sizeof(float) * ldvt_t * MAX(1,n) );
            if( vt_t == NULL ) {
                info = LAPACK_TRANSPOSE_MEMORY_ERROR;
                goto exit_level_2;
            }
        }
        /* Transpose input matrices */
        LAPACKE_sge_trans( matrix_layout, m, n, a, lda, a_t, lda_t );
        /* Call LAPACK function and adjust info */
        LAPACK_sgesdd( &jobz, &m, &n, a_t, &lda_t, s, u_t, &ldu_t, vt_t,
                       &ldvt_t, work, &lwork, iwork, &info );
        if( info < 0 ) {
            info = info - 1;
        }
        /* Transpose output matrices */
        LAPACKE_sge_trans( LAPACK_COL_MAJOR, m, n, a_t, lda_t, a, lda );
        if( LAPACKE_lsame( jobz, 'a' ) || LAPACKE_lsame( jobz, 's' ) ||
            ( LAPACKE_lsame( jobz, 'o' ) && (m<n) ) ) {
            LAPACKE_sge_trans( LAPACK_COL_MAJOR, nrows_u, ncols_u, u_t, ldu_t,
                               u, ldu );
        }
        if( LAPACKE_lsame( jobz, 'a' ) || LAPACKE_lsame( jobz, 's' ) ||
            ( LAPACKE_lsame( jobz, 'o' ) && (m>=n) ) ) {
            LAPACKE_sge_trans( LAPACK_COL_MAJOR, nrows_vt, n, vt_t, ldvt_t, vt,
                               ldvt );
        }
        /* Release memory and exit */
        if( LAPACKE_lsame( jobz, 'a' ) || LAPACKE_lsame( jobz, 's' ) ||
            ( LAPACKE_lsame( jobz, 'o' ) && (m>=n) ) ) {
            LAPACKE_free( vt_t );
        }
exit_level_2:
        if( LAPACKE_lsame( jobz, 'a' ) || LAPACKE_lsame( jobz, 's' ) ||
            ( LAPACKE_lsame( jobz, 'o' ) && (m<n) ) ) {
            LAPACKE_free( u_t );
        }
exit_level_1:
        LAPACKE_free( a_t );
exit_level_0:
        if( info == LAPACK_TRANSPOSE_MEMORY_ERROR ) {
            LAPACKE_xerbla( "LAPACKE_sgesdd_work", info );
        }
    } else {
        info = -1;
        LAPACKE_xerbla( "LAPACKE_sgesdd_work", info );
    }
    return info;
}
