claswp.f

          SUBROUTINE CLASWP( N, A, LDA, K1, K2, IPIV, INCX )
    *
    *  -- LAPACK auxiliary routine (version 3.1) --
    *     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
    *     November 2006
    *
    *     .. Scalar Arguments ..
          INTEGER            INCX, K1, K2, LDA, N
    *     ..
    *     .. Array Arguments ..
          INTEGER            IPIV( * )
          COMPLEX            A( LDA, * )
    *     ..
    *
    *  Purpose
    *  =======
    *
    *  CLASWP performs a series of row interchanges on the matrix A.
    *  One row interchange is initiated for each of rows K1 through K2 of A.
    *
    *  Arguments
    *  =========
    *
    *  N       (input) INTEGER
    *          The number of columns of the matrix A.
    *
    *  A       (input/output) COMPLEX 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.
    *
    *  LDA     (input) INTEGER
    *          The leading dimension of the array A.
    *
    *  K1      (input) INTEGER
    *          The first element of IPIV for which a row interchange will
    *          be done.
    *
    *  K2      (input) INTEGER
    *          The last element of IPIV for which a row interchange will
    *          be done.
    *
    *  IPIV    (input) 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.
    *
    *  INCX    (input) INTEGER
    *          The increment between successive values of IPIV.  If IPIV
    *          is negative, the pivots are applied in reverse order.
    *
    *  Further Details
    *  ===============
    *
    *  Modified by
    *   R. C. Whaley, Computer Science Dept., Univ. of Tenn., Knoxville, USA
    *
    * =====================================================================
    *
    *     .. Local Scalars ..
          INTEGER            I, I1, I2, INC, IP, IX, IX0, J, K, N32
          COMPLEX            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 CLASWP
    *
          END