LAPACK  3.6.1
LAPACK: Linear Algebra PACKage
subroutine slaswp ( integer  N,
real, dimension( lda, * )  A,
integer  LDA,
integer  K1,
integer  K2,
integer, dimension( * )  IPIV,
integer  INCX 
)

SLASWP performs a series of row interchanges on a general rectangular matrix.

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Purpose: 
 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.
Parameters
[in]N
          N is INTEGER
          The number of columns of the matrix A.
[in,out]A
          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.
[in]LDA
          LDA is INTEGER
          The leading dimension of the array A.
[in]K1
          K1 is INTEGER
          The first element of IPIV for which a row interchange will
          be done.
[in]K2
          K2 is INTEGER
          The last element of IPIV for which a row interchange will
          be done.
[in]IPIV
          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.
[in]INCX
          INCX is INTEGER
          The increment between successive values of IPIV.  If IPIV
          is negative, the pivots are applied in reverse order.
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date
September 2012
Further Details: 
  Modified by
   R. C. Whaley, Computer Science Dept., Univ. of Tenn., Knoxville, USA

Definition at line 116 of file slaswp.f.

116 *
117 * -- LAPACK auxiliary routine (version 3.4.2) --
118 * -- LAPACK is a software package provided by Univ. of Tennessee, --
119 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
120 * September 2012
121 *
122 * .. Scalar Arguments ..
123  INTEGER incx, k1, k2, lda, n
124 * ..
125 * .. Array Arguments ..
126  INTEGER ipiv( * )
127  REAL a( lda, * )
128 * ..
129 *
130 * =====================================================================
131 *
132 * .. Local Scalars ..
133  INTEGER i, i1, i2, inc, ip, ix, ix0, j, k, n32
134  REAL temp
135 * ..
136 * .. Executable Statements ..
137 *
138 * Interchange row I with row IPIV(I) for each of rows K1 through K2.
139 *
140  IF( incx.GT.0 ) THEN
141  ix0 = k1
142  i1 = k1
143  i2 = k2
144  inc = 1
145  ELSE IF( incx.LT.0 ) THEN
146  ix0 = 1 + ( 1-k2 )*incx
147  i1 = k2
148  i2 = k1
149  inc = -1
150  ELSE
151  RETURN
152  END IF
153 *
154  n32 = ( n / 32 )*32
155  IF( n32.NE.0 ) THEN
156  DO 30 j = 1, n32, 32
157  ix = ix0
158  DO 20 i = i1, i2, inc
159  ip = ipiv( ix )
160  IF( ip.NE.i ) THEN
161  DO 10 k = j, j + 31
162  temp = a( i, k )
163  a( i, k ) = a( ip, k )
164  a( ip, k ) = temp
165  10 CONTINUE
166  END IF
167  ix = ix + incx
168  20 CONTINUE
169  30 CONTINUE
170  END IF
171  IF( n32.NE.n ) THEN
172  n32 = n32 + 1
173  ix = ix0
174  DO 50 i = i1, i2, inc
175  ip = ipiv( ix )
176  IF( ip.NE.i ) THEN
177  DO 40 k = n32, n
178  temp = a( i, k )
179  a( i, k ) = a( ip, k )
180  a( ip, k ) = temp
181  40 CONTINUE
182  END IF
183  ix = ix + incx
184  50 CONTINUE
185  END IF
186 *
187  RETURN
188 *
189 * End of SLASWP
190 *

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