LAPACK  3.8.0
LAPACK: Linear Algebra PACKage
zlaswp.f
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1 *> \brief \b ZLASWP performs a series of row interchanges on a general rectangular matrix.
2 *
3 * =========== DOCUMENTATION ===========
4 *
5 * Online html documentation available at
6 * http://www.netlib.org/lapack/explore-html/
7 *
8 *> \htmlonly
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15 *> [TXT]</a>
16 *> \endhtmlonly
17 *
18 * Definition:
19 * ===========
20 *
21 * SUBROUTINE ZLASWP( N, A, LDA, K1, K2, IPIV, INCX )
22 *
23 * .. Scalar Arguments ..
24 * INTEGER INCX, K1, K2, LDA, N
25 * ..
26 * .. Array Arguments ..
27 * INTEGER IPIV( * )
28 * COMPLEX*16 A( LDA, * )
29 * ..
30 *
31 *
32 *> \par Purpose:
33 * =============
34 *>
35 *> \verbatim
36 *>
37 *> ZLASWP performs a series of row interchanges on the matrix A.
38 *> One row interchange is initiated for each of rows K1 through K2 of A.
39 *> \endverbatim
40 *
41 * Arguments:
42 * ==========
43 *
44 *> \param[in] N
45 *> \verbatim
46 *> N is INTEGER
47 *> The number of columns of the matrix A.
48 *> \endverbatim
49 *>
50 *> \param[in,out] A
51 *> \verbatim
52 *> A is COMPLEX*16 array, dimension (LDA,N)
53 *> On entry, the matrix of column dimension N to which the row
54 *> interchanges will be applied.
55 *> On exit, the permuted matrix.
56 *> \endverbatim
57 *>
58 *> \param[in] LDA
59 *> \verbatim
60 *> LDA is INTEGER
61 *> The leading dimension of the array A.
62 *> \endverbatim
63 *>
64 *> \param[in] K1
65 *> \verbatim
66 *> K1 is INTEGER
67 *> The first element of IPIV for which a row interchange will
68 *> be done.
69 *> \endverbatim
70 *>
71 *> \param[in] K2
72 *> \verbatim
73 *> K2 is INTEGER
74 *> (K2-K1+1) is the number of elements of IPIV for which a row
75 *> interchange will be done.
76 *> \endverbatim
77 *>
78 *> \param[in] IPIV
79 *> \verbatim
80 *> IPIV is INTEGER array, dimension (K1+(K2-K1)*abs(INCX))
81 *> The vector of pivot indices. Only the elements in positions
82 *> K1 through K1+(K2-K1)*abs(INCX) of IPIV are accessed.
83 *> IPIV(K1+(K-K1)*abs(INCX)) = L implies rows K and L are to be
84 *> interchanged.
85 *> \endverbatim
86 *>
87 *> \param[in] INCX
88 *> \verbatim
89 *> INCX is INTEGER
90 *> The increment between successive values of IPIV. If INCX
91 *> is negative, the pivots are applied in reverse order.
92 *> \endverbatim
93 *
94 * Authors:
95 * ========
96 *
97 *> \author Univ. of Tennessee
98 *> \author Univ. of California Berkeley
99 *> \author Univ. of Colorado Denver
100 *> \author NAG Ltd.
101 *
102 *> \date June 2017
103 *
104 *> \ingroup complex16OTHERauxiliary
105 *
106 *> \par Further Details:
107 * =====================
108 *>
109 *> \verbatim
110 *>
111 *> Modified by
112 *> R. C. Whaley, Computer Science Dept., Univ. of Tenn., Knoxville, USA
113 *> \endverbatim
114 *>
115 * =====================================================================
116  SUBROUTINE zlaswp( N, A, LDA, K1, K2, IPIV, INCX )
117 *
118 * -- LAPACK auxiliary routine (version 3.7.1) --
119 * -- LAPACK is a software package provided by Univ. of Tennessee, --
120 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
121 * June 2017
122 *
123 * .. Scalar Arguments ..
124  INTEGER INCX, K1, K2, LDA, N
125 * ..
126 * .. Array Arguments ..
127  INTEGER IPIV( * )
128  COMPLEX*16 A( lda, * )
129 * ..
130 *
131 * =====================================================================
132 *
133 * .. Local Scalars ..
134  INTEGER I, I1, I2, INC, IP, IX, IX0, J, K, N32
135  COMPLEX*16 TEMP
136 * ..
137 * .. Executable Statements ..
138 *
139 * Interchange row I with row IPIV(K1+(I-K1)*abs(INCX)) for each of rows
140 * K1 through K2.
141 *
142  IF( incx.GT.0 ) THEN
143  ix0 = k1
144  i1 = k1
145  i2 = k2
146  inc = 1
147  ELSE IF( incx.LT.0 ) THEN
148  ix0 = k1 + ( k1-k2 )*incx
149  i1 = k2
150  i2 = k1
151  inc = -1
152  ELSE
153  RETURN
154  END IF
155 *
156  n32 = ( n / 32 )*32
157  IF( n32.NE.0 ) THEN
158  DO 30 j = 1, n32, 32
159  ix = ix0
160  DO 20 i = i1, i2, inc
161  ip = ipiv( ix )
162  IF( ip.NE.i ) THEN
163  DO 10 k = j, j + 31
164  temp = a( i, k )
165  a( i, k ) = a( ip, k )
166  a( ip, k ) = temp
167  10 CONTINUE
168  END IF
169  ix = ix + incx
170  20 CONTINUE
171  30 CONTINUE
172  END IF
173  IF( n32.NE.n ) THEN
174  n32 = n32 + 1
175  ix = ix0
176  DO 50 i = i1, i2, inc
177  ip = ipiv( ix )
178  IF( ip.NE.i ) THEN
179  DO 40 k = n32, n
180  temp = a( i, k )
181  a( i, k ) = a( ip, k )
182  a( ip, k ) = temp
183  40 CONTINUE
184  END IF
185  ix = ix + incx
186  50 CONTINUE
187  END IF
188 *
189  RETURN
190 *
191 * End of ZLASWP
192 *
193  END
subroutine zlaswp(N, A, LDA, K1, K2, IPIV, INCX)
ZLASWP performs a series of row interchanges on a general rectangular matrix.
Definition: zlaswp.f:117