1: *> \brief \b ZHESWAPR applies an elementary permutation on the rows and columns of a Hermitian matrix.
2: *
3: * =========== DOCUMENTATION ===========
4: *
5: * Online html documentation available at
6: * http://www.netlib.org/lapack/explore-html/
7: *
8: *> \htmlonly
9: *> Download ZHESWAPR + dependencies
10: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/zheswapr.f">
11: *> [TGZ]</a>
12: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/zheswapr.f">
13: *> [ZIP]</a>
14: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/zheswapr.f">
15: *> [TXT]</a>
16: *> \endhtmlonly
17: *
18: * Definition:
19: * ===========
20: *
21: * SUBROUTINE ZHESWAPR( UPLO, N, A, LDA, I1, I2)
22: *
23: * .. Scalar Arguments ..
24: * CHARACTER UPLO
25: * INTEGER I1, I2, LDA, N
26: * ..
27: * .. Array Arguments ..
28: * COMPLEX*16 A( LDA, N )
29: *
30: *
31: *> \par Purpose:
32: * =============
33: *>
34: *> \verbatim
35: *>
36: *> ZHESWAPR applies an elementary permutation on the rows and the columns of
37: *> a hermitian matrix.
38: *> \endverbatim
39: *
40: * Arguments:
41: * ==========
42: *
43: *> \param[in] UPLO
44: *> \verbatim
45: *> UPLO is CHARACTER*1
46: *> Specifies whether the details of the factorization are stored
47: *> as an upper or lower triangular matrix.
48: *> = 'U': Upper triangular, form is A = U*D*U**T;
49: *> = 'L': Lower triangular, form is A = L*D*L**T.
50: *> \endverbatim
51: *>
52: *> \param[in] N
53: *> \verbatim
54: *> N is INTEGER
55: *> The order of the matrix A. N >= 0.
56: *> \endverbatim
57: *>
58: *> \param[in,out] A
59: *> \verbatim
60: *> A is COMPLEX*16 array, dimension (LDA,N)
61: *> On entry, the NB diagonal matrix D and the multipliers
62: *> used to obtain the factor U or L as computed by CSYTRF.
63: *>
64: *> On exit, if INFO = 0, the (symmetric) inverse of the original
65: *> matrix. If UPLO = 'U', the upper triangular part of the
66: *> inverse is formed and the part of A below the diagonal is not
67: *> referenced; if UPLO = 'L' the lower triangular part of the
68: *> inverse is formed and the part of A above the diagonal is
69: *> not referenced.
70: *> \endverbatim
71: *>
72: *> \param[in] LDA
73: *> \verbatim
74: *> LDA is INTEGER
75: *> The leading dimension of the array A. LDA >= max(1,N).
76: *> \endverbatim
77: *>
78: *> \param[in] I1
79: *> \verbatim
80: *> I1 is INTEGER
81: *> Index of the first row to swap
82: *> \endverbatim
83: *>
84: *> \param[in] I2
85: *> \verbatim
86: *> I2 is INTEGER
87: *> Index of the second row to swap
88: *> \endverbatim
89: *
90: * Authors:
91: * ========
92: *
93: *> \author Univ. of Tennessee
94: *> \author Univ. of California Berkeley
95: *> \author Univ. of Colorado Denver
96: *> \author NAG Ltd.
97: *
98: *> \date December 2016
99: *
100: *> \ingroup complex16HEauxiliary
101: *
102: * =====================================================================
103: SUBROUTINE ZHESWAPR( UPLO, N, A, LDA, I1, I2)
104: *
105: * -- LAPACK auxiliary routine (version 3.7.0) --
106: * -- LAPACK is a software package provided by Univ. of Tennessee, --
107: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
108: * December 2016
109: *
110: * .. Scalar Arguments ..
111: CHARACTER UPLO
112: INTEGER I1, I2, LDA, N
113: * ..
114: * .. Array Arguments ..
115: COMPLEX*16 A( LDA, N )
116: *
117: * =====================================================================
118: *
119: * ..
120: * .. Local Scalars ..
121: LOGICAL UPPER
122: INTEGER I
123: COMPLEX*16 TMP
124: *
125: * .. External Functions ..
126: LOGICAL LSAME
127: EXTERNAL LSAME
128: * ..
129: * .. External Subroutines ..
130: EXTERNAL ZSWAP
131: * ..
132: * .. Executable Statements ..
133: *
134: UPPER = LSAME( UPLO, 'U' )
135: IF (UPPER) THEN
136: *
137: * UPPER
138: * first swap
139: * - swap column I1 and I2 from I1 to I1-1
140: CALL ZSWAP( I1-1, A(1,I1), 1, A(1,I2), 1 )
141: *
142: * second swap :
143: * - swap A(I1,I1) and A(I2,I2)
144: * - swap row I1 from I1+1 to I2-1 with col I2 from I1+1 to I2-1
145: * - swap A(I2,I1) and A(I1,I2)
146:
147: TMP=A(I1,I1)
148: A(I1,I1)=A(I2,I2)
149: A(I2,I2)=TMP
150: *
151: DO I=1,I2-I1-1
152: TMP=A(I1,I1+I)
153: A(I1,I1+I)=DCONJG(A(I1+I,I2))
154: A(I1+I,I2)=DCONJG(TMP)
155: END DO
156: *
157: A(I1,I2)=DCONJG(A(I1,I2))
158:
159: *
160: * third swap
161: * - swap row I1 and I2 from I2+1 to N
162: DO I=I2+1,N
163: TMP=A(I1,I)
164: A(I1,I)=A(I2,I)
165: A(I2,I)=TMP
166: END DO
167: *
168: ELSE
169: *
170: * LOWER
171: * first swap
172: * - swap row I1 and I2 from 1 to I1-1
173: CALL ZSWAP ( I1-1, A(I1,1), LDA, A(I2,1), LDA )
174: *
175: * second swap :
176: * - swap A(I1,I1) and A(I2,I2)
177: * - swap col I1 from I1+1 to I2-1 with row I2 from I1+1 to I2-1
178: * - swap A(I2,I1) and A(I1,I2)
179:
180: TMP=A(I1,I1)
181: A(I1,I1)=A(I2,I2)
182: A(I2,I2)=TMP
183: *
184: DO I=1,I2-I1-1
185: TMP=A(I1+I,I1)
186: A(I1+I,I1)=DCONJG(A(I2,I1+I))
187: A(I2,I1+I)=DCONJG(TMP)
188: END DO
189: *
190: A(I2,I1)=DCONJG(A(I2,I1))
191: *
192: * third swap
193: * - swap col I1 and I2 from I2+1 to N
194: DO I=I2+1,N
195: TMP=A(I,I1)
196: A(I,I1)=A(I,I2)
197: A(I,I2)=TMP
198: END DO
199: *
200: ENDIF
201:
202: END SUBROUTINE ZHESWAPR
203:
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