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: *> \ingroup complex16HEauxiliary
99: *
100: * =====================================================================
101: SUBROUTINE ZHESWAPR( UPLO, N, A, LDA, I1, I2)
102: *
103: * -- LAPACK auxiliary routine --
104: * -- LAPACK is a software package provided by Univ. of Tennessee, --
105: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
106: *
107: * .. Scalar Arguments ..
108: CHARACTER UPLO
109: INTEGER I1, I2, LDA, N
110: * ..
111: * .. Array Arguments ..
112: COMPLEX*16 A( LDA, N )
113: *
114: * =====================================================================
115: *
116: * ..
117: * .. Local Scalars ..
118: LOGICAL UPPER
119: INTEGER I
120: COMPLEX*16 TMP
121: *
122: * .. External Functions ..
123: LOGICAL LSAME
124: EXTERNAL LSAME
125: * ..
126: * .. External Subroutines ..
127: EXTERNAL ZSWAP
128: * ..
129: * .. Executable Statements ..
130: *
131: UPPER = LSAME( UPLO, 'U' )
132: IF (UPPER) THEN
133: *
134: * UPPER
135: * first swap
136: * - swap column I1 and I2 from I1 to I1-1
137: CALL ZSWAP( I1-1, A(1,I1), 1, A(1,I2), 1 )
138: *
139: * second swap :
140: * - swap A(I1,I1) and A(I2,I2)
141: * - swap row I1 from I1+1 to I2-1 with col I2 from I1+1 to I2-1
142: * - swap A(I2,I1) and A(I1,I2)
143:
144: TMP=A(I1,I1)
145: A(I1,I1)=A(I2,I2)
146: A(I2,I2)=TMP
147: *
148: DO I=1,I2-I1-1
149: TMP=A(I1,I1+I)
150: A(I1,I1+I)=DCONJG(A(I1+I,I2))
151: A(I1+I,I2)=DCONJG(TMP)
152: END DO
153: *
154: A(I1,I2)=DCONJG(A(I1,I2))
155:
156: *
157: * third swap
158: * - swap row I1 and I2 from I2+1 to N
159: DO I=I2+1,N
160: TMP=A(I1,I)
161: A(I1,I)=A(I2,I)
162: A(I2,I)=TMP
163: END DO
164: *
165: ELSE
166: *
167: * LOWER
168: * first swap
169: * - swap row I1 and I2 from 1 to I1-1
170: CALL ZSWAP ( I1-1, A(I1,1), LDA, A(I2,1), LDA )
171: *
172: * second swap :
173: * - swap A(I1,I1) and A(I2,I2)
174: * - swap col I1 from I1+1 to I2-1 with row I2 from I1+1 to I2-1
175: * - swap A(I2,I1) and A(I1,I2)
176:
177: TMP=A(I1,I1)
178: A(I1,I1)=A(I2,I2)
179: A(I2,I2)=TMP
180: *
181: DO I=1,I2-I1-1
182: TMP=A(I1+I,I1)
183: A(I1+I,I1)=DCONJG(A(I2,I1+I))
184: A(I2,I1+I)=DCONJG(TMP)
185: END DO
186: *
187: A(I2,I1)=DCONJG(A(I2,I1))
188: *
189: * third swap
190: * - swap col I1 and I2 from I2+1 to N
191: DO I=I2+1,N
192: TMP=A(I,I1)
193: A(I,I1)=A(I,I2)
194: A(I,I2)=TMP
195: END DO
196: *
197: ENDIF
198:
199: END SUBROUTINE ZHESWAPR
200:
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