1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
|
*> \brief \b SSYSWAPR applies an elementary permutation on the rows and columns of a symmetric matrix.
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
*> Download SSYSWAPR + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/ssyswapr.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/ssyswapr.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/ssyswapr.f">
*> [TXT]</a>
*> \endhtmlonly
*
* Definition:
* ===========
*
* SUBROUTINE SSYSWAPR( UPLO, N, A, LDA, I1, I2)
*
* .. Scalar Arguments ..
* CHARACTER UPLO
* INTEGER I1, I2, LDA, N
* ..
* .. Array Arguments ..
* REAL A( LDA, N )
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> SSYSWAPR applies an elementary permutation on the rows and the columns of
*> a symmetric matrix.
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] UPLO
*> \verbatim
*> UPLO is CHARACTER*1
*> Specifies whether the details of the factorization are stored
*> as an upper or lower triangular matrix.
*> = 'U': Upper triangular, form is A = U*D*U**T;
*> = 'L': Lower triangular, form is A = L*D*L**T.
*> \endverbatim
*>
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> The order of the matrix A. N >= 0.
*> \endverbatim
*>
*> \param[in,out] A
*> \verbatim
*> A is REAL array, dimension (LDA,N)
*> On entry, the NB diagonal matrix D and the multipliers
*> used to obtain the factor U or L as computed by SSYTRF.
*>
*> On exit, if INFO = 0, the (symmetric) inverse of the original
*> matrix. If UPLO = 'U', the upper triangular part of the
*> inverse is formed and the part of A below the diagonal is not
*> referenced; if UPLO = 'L' the lower triangular part of the
*> inverse is formed and the part of A above the diagonal is
*> not referenced.
*> \endverbatim
*>
*> \param[in] LDA
*> \verbatim
*> LDA is INTEGER
*> The leading dimension of the array A. LDA >= max(1,N).
*> \endverbatim
*>
*> \param[in] I1
*> \verbatim
*> I1 is INTEGER
*> Index of the first row to swap
*> \endverbatim
*>
*> \param[in] I2
*> \verbatim
*> I2 is INTEGER
*> Index of the second row to swap
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date December 2016
*
*> \ingroup realSYauxiliary
*
* =====================================================================
SUBROUTINE SSYSWAPR( UPLO, N, A, LDA, I1, I2)
*
* -- LAPACK auxiliary routine (version 3.7.0) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* December 2016
*
* .. Scalar Arguments ..
CHARACTER UPLO
INTEGER I1, I2, LDA, N
* ..
* .. Array Arguments ..
REAL A( LDA, N )
*
* =====================================================================
*
* ..
* .. Local Scalars ..
LOGICAL UPPER
INTEGER I
REAL TMP
*
* .. External Functions ..
LOGICAL LSAME
EXTERNAL LSAME
* ..
* .. External Subroutines ..
EXTERNAL SSWAP
* ..
* .. Executable Statements ..
*
UPPER = LSAME( UPLO, 'U' )
IF (UPPER) THEN
*
* UPPER
* first swap
* - swap column I1 and I2 from I1 to I1-1
CALL SSWAP( I1-1, A(1,I1), 1, A(1,I2), 1 )
*
* second swap :
* - swap A(I1,I1) and A(I2,I2)
* - swap row I1 from I1+1 to I2-1 with col I2 from I1+1 to I2-1
TMP=A(I1,I1)
A(I1,I1)=A(I2,I2)
A(I2,I2)=TMP
*
DO I=1,I2-I1-1
TMP=A(I1,I1+I)
A(I1,I1+I)=A(I1+I,I2)
A(I1+I,I2)=TMP
END DO
*
* third swap
* - swap row I1 and I2 from I2+1 to N
DO I=I2+1,N
TMP=A(I1,I)
A(I1,I)=A(I2,I)
A(I2,I)=TMP
END DO
*
ELSE
*
* LOWER
* first swap
* - swap row I1 and I2 from I1 to I1-1
CALL SSWAP( I1-1, A(I1,1), LDA, A(I2,1), LDA )
*
* second swap :
* - swap A(I1,I1) and A(I2,I2)
* - swap col I1 from I1+1 to I2-1 with row I2 from I1+1 to I2-1
TMP=A(I1,I1)
A(I1,I1)=A(I2,I2)
A(I2,I2)=TMP
*
DO I=1,I2-I1-1
TMP=A(I1+I,I1)
A(I1+I,I1)=A(I2,I1+I)
A(I2,I1+I)=TMP
END DO
*
* third swap
* - swap col I1 and I2 from I2+1 to N
DO I=I2+1,N
TMP=A(I,I1)
A(I,I1)=A(I,I2)
A(I,I2)=TMP
END DO
*
ENDIF
END SUBROUTINE SSYSWAPR
|
