1: *> \brief \b DLASWP 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
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: *> (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 doubleOTHERauxiliary
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 DLASWP( 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: DOUBLE PRECISION A( LDA, * )
129: * ..
130: *
131: * =====================================================================
132: *
133: * .. Local Scalars ..
134: INTEGER I, I1, I2, INC, IP, IX, IX0, J, K, N32
135: DOUBLE PRECISION 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 DLASWP
192: *
193: END
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