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dlaswp.f
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*> \brief \b DLASWP 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
*> Download DLASWP + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlaswp.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlaswp.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlaswp.f">
*> [TXT]</a>
*> \endhtmlonly
*
* Definition:
* ===========
*
* SUBROUTINE DLASWP( N, A, LDA, K1, K2, IPIV, INCX )
*
* .. Scalar Arguments ..
* INTEGER INCX, K1, K2, LDA, N
* ..
* .. Array Arguments ..
* INTEGER IPIV( * )
* DOUBLE PRECISION A( LDA, * )
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> DLASWP 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 DOUBLE PRECISION 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
*> The last element of IPIV for which a row interchange will
*> be done.
*> \endverbatim
*>
*> \param[in] IPIV
*> \verbatim
*> IPIV is INTEGER array, dimension (K2*abs(INCX))
*> The vector of pivot indices. Only the elements in positions
*> K1 through K2 of IPIV are accessed.
*> IPIV(K) = 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 IPIV
*> 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.
*
*> \date September 2012
*
*> \ingroup doubleOTHERauxiliary
*
*> \par Further Details:
* =====================
*>
*> \verbatim
*>
*> Modified by
*> R. C. Whaley, Computer Science Dept., Univ. of Tenn., Knoxville, USA
*> \endverbatim
*>
* =====================================================================
SUBROUTINE DLASWP( N, A, LDA, K1, K2, IPIV, INCX )
*
* -- LAPACK auxiliary routine (version 3.4.2) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* September 2012
*
* .. Scalar Arguments ..
INTEGER INCX, K1, K2, LDA, N
* ..
* .. Array Arguments ..
INTEGER IPIV( * )
DOUBLE PRECISION A( LDA, * )
* ..
*
* =====================================================================
*
* .. Local Scalars ..
INTEGER I, I1, I2, INC, IP, IX, IX0, J, K, N32
DOUBLE PRECISION TEMP
* ..
* .. Executable Statements ..
*
* Interchange row I with row IPIV(I) 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 = 1 + ( 1-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 DLASWP
*
END

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