Annotation of rpl/lapack/lapack/dlaswp.f, revision 1.12
1.11 bertrand 1: *> \brief \b DLASWP performs a series of row interchanges on a general rectangular matrix.
1.8 bertrand 2: *
3: * =========== DOCUMENTATION ===========
4: *
5: * Online html documentation available at
6: * http://www.netlib.org/lapack/explore-html/
7: *
8: *> \htmlonly
9: *> Download DLASWP + dependencies
10: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlaswp.f">
11: *> [TGZ]</a>
12: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlaswp.f">
13: *> [ZIP]</a>
14: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlaswp.f">
15: *> [TXT]</a>
16: *> \endhtmlonly
17: *
18: * Definition:
19: * ===========
20: *
21: * SUBROUTINE DLASWP( 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: * DOUBLE PRECISION A( LDA, * )
29: * ..
30: *
31: *
32: *> \par Purpose:
33: * =============
34: *>
35: *> \verbatim
36: *>
37: *> DLASWP 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 DOUBLE PRECISION 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: *> The last element of IPIV for which a row interchange will
75: *> be done.
76: *> \endverbatim
77: *>
78: *> \param[in] IPIV
79: *> \verbatim
80: *> IPIV is INTEGER array, dimension (K2*abs(INCX))
81: *> The vector of pivot indices. Only the elements in positions
82: *> K1 through K2 of IPIV are accessed.
83: *> IPIV(K) = L implies rows K and L are to be interchanged.
84: *> \endverbatim
85: *>
86: *> \param[in] INCX
87: *> \verbatim
88: *> INCX is INTEGER
89: *> The increment between successive values of IPIV. If IPIV
90: *> is negative, the pivots are applied in reverse order.
91: *> \endverbatim
92: *
93: * Authors:
94: * ========
95: *
96: *> \author Univ. of Tennessee
97: *> \author Univ. of California Berkeley
98: *> \author Univ. of Colorado Denver
99: *> \author NAG Ltd.
100: *
1.11 bertrand 101: *> \date September 2012
1.8 bertrand 102: *
103: *> \ingroup doubleOTHERauxiliary
104: *
105: *> \par Further Details:
106: * =====================
107: *>
108: *> \verbatim
109: *>
110: *> Modified by
111: *> R. C. Whaley, Computer Science Dept., Univ. of Tenn., Knoxville, USA
112: *> \endverbatim
113: *>
114: * =====================================================================
1.1 bertrand 115: SUBROUTINE DLASWP( N, A, LDA, K1, K2, IPIV, INCX )
116: *
1.11 bertrand 117: * -- LAPACK auxiliary routine (version 3.4.2) --
1.1 bertrand 118: * -- LAPACK is a software package provided by Univ. of Tennessee, --
119: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
1.11 bertrand 120: * September 2012
1.1 bertrand 121: *
122: * .. Scalar Arguments ..
123: INTEGER INCX, K1, K2, LDA, N
124: * ..
125: * .. Array Arguments ..
126: INTEGER IPIV( * )
127: DOUBLE PRECISION A( LDA, * )
128: * ..
129: *
130: * =====================================================================
131: *
132: * .. Local Scalars ..
133: INTEGER I, I1, I2, INC, IP, IX, IX0, J, K, N32
134: DOUBLE PRECISION 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 DLASWP
190: *
191: END
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