*> \brief \b SLASWP performs a series of row interchanges on a general rectangular matrix.
*
*  =========== DOCUMENTATION ===========
*
* Online html documentation available at
*            http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/slaswp.f">
*> [TXT]</a>
*> \endhtmlonly
*
*  Definition:
*  ===========
*
*       SUBROUTINE SLASWP( N, A, LDA, K1, K2, IPIV, INCX )
*
*       .. Scalar Arguments ..
*       INTEGER            INCX, K1, K2, LDA, N
*       ..
*       .. Array Arguments ..
*       INTEGER            IPIV( * )
*       REAL               A( LDA, * )
*       ..
*
*
*> \par Purpose:
*  =============
*>
*> \verbatim
*>
*> SLASWP performs a series of row interchanges on the matrix A.
*> One row interchange is initiated for each of rows K1 through K2 of A.
*> \endverbatim
*
*  Arguments:
*  ==========
*
*> \param[in] N
*> \verbatim
*>          N is INTEGER
*>          The number of columns of the matrix A.
*> \endverbatim
*>
*> \param[in,out] A
*> \verbatim
*>          A is REAL array, dimension (LDA,N)
*>          On entry, the matrix of column dimension N to which the row
*>          interchanges will be applied.
*>          On exit, the permuted matrix.
*> \endverbatim
*>
*> \param[in] LDA
*> \verbatim
*>          LDA is INTEGER
*>          The leading dimension of the array A.
*> \endverbatim
*>
*> \param[in] K1
*> \verbatim
*>          K1 is INTEGER
*>          The first element of IPIV for which a row interchange will
*>          be done.
*> \endverbatim
*>
*> \param[in] K2
*> \verbatim
*>          K2 is INTEGER
*>          (K2-K1+1) is the number of elements of IPIV for which a row
*>          interchange will be done.
*> \endverbatim
*>
*> \param[in] IPIV
*> \verbatim
*>          IPIV is INTEGER array, dimension (K1+(K2-K1)*abs(INCX))
*>          The vector of pivot indices. Only the elements in positions
*>          K1 through K1+(K2-K1)*abs(INCX) of IPIV are accessed.
*>          IPIV(K1+(K-K1)*abs(INCX)) = L implies rows K and L are to be
*>          interchanged.
*> \endverbatim
*>
*> \param[in] INCX
*> \verbatim
*>          INCX is INTEGER
*>          The increment between successive values of IPIV. If INCX
*>          is negative, the pivots are applied in reverse order.
*> \endverbatim
*
*  Authors:
*  ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \ingroup laswp
*
*> \par Further Details:
*  =====================
*>
*> \verbatim
*>
*>  Modified by
*>   R. C. Whaley, Computer Science Dept., Univ. of Tenn., Knoxville, USA
*> \endverbatim
*>
*  =====================================================================
      SUBROUTINE SLASWP( N, A, LDA, K1, K2, IPIV, INCX )
*
*  -- LAPACK auxiliary routine --
*  -- LAPACK is a software package provided by Univ. of Tennessee,    --
*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
*
*     .. Scalar Arguments ..
      INTEGER            INCX, K1, K2, LDA, N
*     ..
*     .. Array Arguments ..
      INTEGER            IPIV( * )
      REAL               A( LDA, * )
*     ..
*
* =====================================================================
*
*     .. Local Scalars ..
      INTEGER            I, I1, I2, INC, IP, IX, IX0, J, K, N32
      REAL               TEMP
*     ..
*     .. Executable Statements ..
*
*     Interchange row I with row IPIV(K1+(I-K1)*abs(INCX)) for each of rows
*     K1 through K2.
*
      IF( INCX.GT.0 ) THEN
         IX0 = K1
         I1 = K1
         I2 = K2
         INC = 1
      ELSE IF( INCX.LT.0 ) THEN
         IX0 = K1 + ( K1-K2 )*INCX
         I1 = K2
         I2 = K1
         INC = -1
      ELSE
         RETURN
      END IF
*
      N32 = ( N / 32 )*32
      IF( N32.NE.0 ) THEN
         DO 30 J = 1, N32, 32
            IX = IX0
            DO 20 I = I1, I2, INC
               IP = IPIV( IX )
               IF( IP.NE.I ) THEN
                  DO 10 K = J, J + 31
                     TEMP = A( I, K )
                     A( I, K ) = A( IP, K )
                     A( IP, K ) = TEMP
   10             CONTINUE
               END IF
               IX = IX + INCX
   20       CONTINUE
   30    CONTINUE
      END IF
      IF( N32.NE.N ) THEN
         N32 = N32 + 1
         IX = IX0
         DO 50 I = I1, I2, INC
            IP = IPIV( IX )
            IF( IP.NE.I ) THEN
               DO 40 K = N32, N
                  TEMP = A( I, K )
                  A( I, K ) = A( IP, K )
                  A( IP, K ) = TEMP
   40          CONTINUE
            END IF
            IX = IX + INCX
   50    CONTINUE
      END IF
*
      RETURN
*
*     End of SLASWP
*
      END
