lapacke_dgesvdx.c

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* Contents: Native high-level C interface to LAPACK function dgesvdx
* Author: Intel Corporation
*****************************************************************************/
 
#include "lapacke_utils.h"
 
lapack_int LAPACKE_dgesvdx( int matrix_layout, char jobu, char jobvt, char range,
                           lapack_int m, lapack_int n, double* a,
                           lapack_int lda, double vl, double vu,
                           lapack_int il, lapack_int iu, lapack_int* ns,
                           double* s, double* u, lapack_int ldu,
                           double* vt, lapack_int ldvt,
                           lapack_int* superb )
{
    lapack_int info = 0;
    lapack_int lwork = -1;
    double* work = NULL;
    double work_query;
    lapack_int* iwork = NULL;
    lapack_int i;
    if( matrix_layout != LAPACK_COL_MAJOR && matrix_layout != LAPACK_ROW_MAJOR ) {
        LAPACKE_xerbla( "LAPACKE_dgesvdx", -1 );
        return -1;
    }
#ifndef LAPACK_DISABLE_NAN_CHECK
    if( LAPACKE_get_nancheck() ) {
        /* Optionally check input matrices for NaNs */
        if( LAPACKE_dge_nancheck( matrix_layout, m, n, a, lda ) ) {
            return -6;
        }
    }
#endif
    /* Query optimal working array(s) size */
    info = LAPACKE_dgesvdx_work( matrix_layout, jobu, jobvt, range,
                                 m, n, a, lda, vl, vu, il, iu, ns, s, u,
                                 ldu, vt, ldvt, &work_query, lwork, iwork );
    if( info != 0 ) {
        goto exit_level_0;
    }
    lwork = (lapack_int)work_query;
    /* Allocate memory for work arrays */
    work = (double*)LAPACKE_malloc( sizeof(double) * lwork );
    if( work == NULL ) {
        info = LAPACK_WORK_MEMORY_ERROR;
        goto exit_level_0;
    }
    iwork = (lapack_int*)LAPACKE_malloc( sizeof(lapack_int) * MAX(1,(12*MIN(m,n))) );
    if( iwork == NULL ) {
        info = LAPACK_WORK_MEMORY_ERROR;
        goto exit_level_1;
    }
    /* Call middle-level interface */
    info = LAPACKE_dgesvdx_work( matrix_layout, jobu, jobvt,  range,
                                 m, n, a, lda, vl, vu, il, iu, ns, s, u,
                                 ldu, vt, ldvt, work, lwork, iwork );
    /* Backup significant data from working array(s) */
    for( i=0; i<12*MIN(m,n)-1; i++ ) {
        superb[i] = iwork[i+1];
    }
    /* Release memory and exit */
    LAPACKE_free( iwork );
exit_level_1:
    LAPACKE_free( work );
exit_level_0:
    if( info == LAPACK_WORK_MEMORY_ERROR ) {
        LAPACKE_xerbla( "LAPACKE_dgesvdx", info );
    }
    return info;
}