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* Contents: Native C interface to LAPACK utility function
* Author: Intel Corporation
* Created in February, 2010
*****************************************************************************/

#include "lapacke_utils.h"

/* Converts input RFP matrix from row-major(C) to column-major(Fortran)
 * layout or vice versa.
 * This functions does copy diagonal for both unit and non-unit cases.
 */

void LAPACKE_dtf_trans( int matrix_order, char transr, char uplo, char diag,
                        lapack_int n, const double *in,
                        double *out )
{
    lapack_int row, col;
    lapack_logical rowmaj, ntr, lower, unit;

    if( in == NULL || out == NULL ) return ;

    rowmaj = (matrix_order == LAPACK_ROW_MAJOR);
    ntr    = LAPACKE_lsame( transr, 'n' );
    lower  = LAPACKE_lsame( uplo,   'l' );
    unit   = LAPACKE_lsame( diag,   'u' );

    if( ( !rowmaj && ( matrix_order != LAPACK_COL_MAJOR ) ) ||
        ( !ntr    && !LAPACKE_lsame( transr, 't' ) &&
                     !LAPACKE_lsame( transr, 'c' ) ) ||
        ( !lower  && !LAPACKE_lsame( uplo,   'u' ) ) ||
        ( !unit   && !LAPACKE_lsame( diag,   'n' ) ) ) {
        /* Just exit if input parameters are wrong */
        return;
    }

    /* Determine parameters of array representing RFP */
    if( ntr ) {
        if( n%2 == 0 ) {
            row = n + 1;
            col = n / 2;
        } else {
            row = n;
            col = (n + 1) / 2;
        }
    } else {
        if( n%2 == 0 ) {
            row = n / 2;
            col = n + 1;
        } else {
            row = (n + 1) / 2;
            col = n;
        }
    }

    /* Perform conversion: */
    if( rowmaj ) {
        LAPACKE_dge_trans( LAPACK_ROW_MAJOR, row, col, in, col, out, row );
    } else {
        LAPACKE_dge_trans( LAPACK_COL_MAJOR, row, col, in, row, out, col );
    }
}
