Annotation of rpl/lapack/lapack/zsyswapr.f, revision 1.13
1.4 bertrand 1: *> \brief \b ZSYSWAPR
2: *
3: * =========== DOCUMENTATION ===========
4: *
1.10 bertrand 5: * Online html documentation available at
6: * http://www.netlib.org/lapack/explore-html/
1.4 bertrand 7: *
8: *> \htmlonly
1.10 bertrand 9: *> Download ZSYSWAPR + dependencies
10: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/zsyswapr.f">
11: *> [TGZ]</a>
12: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/zsyswapr.f">
13: *> [ZIP]</a>
14: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/zsyswapr.f">
1.4 bertrand 15: *> [TXT]</a>
1.10 bertrand 16: *> \endhtmlonly
1.4 bertrand 17: *
18: * Definition:
19: * ===========
20: *
21: * SUBROUTINE ZSYSWAPR( UPLO, N, A, LDA, I1, I2)
1.10 bertrand 22: *
1.4 bertrand 23: * .. Scalar Arguments ..
24: * CHARACTER UPLO
25: * INTEGER I1, I2, LDA, N
26: * ..
27: * .. Array Arguments ..
28: * COMPLEX*16 A( LDA, N )
1.10 bertrand 29: *
1.4 bertrand 30: *
31: *> \par Purpose:
32: * =============
33: *>
34: *> \verbatim
35: *>
36: *> ZSYSWAPR applies an elementary permutation on the rows and the columns of
37: *> a symmetric 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
1.13 ! bertrand 60: *> A is COMPLEX*16 array, dimension (LDA,*)
! 61: *> On entry, the N-by-N matrix A. On exit, the permuted matrix
! 62: *> where the rows I1 and I2 and columns I1 and I2 are interchanged.
! 63: *> If UPLO = 'U', the interchanges are applied to the upper
! 64: *> triangular part and the strictly lower triangular part of A is
! 65: *> not referenced; if UPLO = 'L', the interchanges are applied to
! 66: *> the lower triangular part and the part of A above the diagonal
! 67: *> is not referenced.
1.4 bertrand 68: *> \endverbatim
69: *>
70: *> \param[in] LDA
71: *> \verbatim
72: *> LDA is INTEGER
73: *> The leading dimension of the array A. LDA >= max(1,N).
74: *> \endverbatim
75: *>
76: *> \param[in] I1
77: *> \verbatim
78: *> I1 is INTEGER
79: *> Index of the first row to swap
80: *> \endverbatim
81: *>
82: *> \param[in] I2
83: *> \verbatim
84: *> I2 is INTEGER
85: *> Index of the second row to swap
86: *> \endverbatim
87: *
88: * Authors:
89: * ========
90: *
1.10 bertrand 91: *> \author Univ. of Tennessee
92: *> \author Univ. of California Berkeley
93: *> \author Univ. of Colorado Denver
94: *> \author NAG Ltd.
1.4 bertrand 95: *
96: *> \ingroup complex16SYauxiliary
97: *
98: * =====================================================================
1.3 bertrand 99: SUBROUTINE ZSYSWAPR( UPLO, N, A, LDA, I1, I2)
1.1 bertrand 100: *
1.13 ! bertrand 101: * -- LAPACK auxiliary routine --
1.1 bertrand 102: * -- LAPACK is a software package provided by Univ. of Tennessee, --
103: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
104: *
105: * .. Scalar Arguments ..
106: CHARACTER UPLO
1.3 bertrand 107: INTEGER I1, I2, LDA, N
1.1 bertrand 108: * ..
109: * .. Array Arguments ..
1.13 ! bertrand 110: COMPLEX*16 A( LDA, * )
1.1 bertrand 111: *
112: * =====================================================================
113: *
114: * ..
115: * .. Local Scalars ..
116: LOGICAL UPPER
1.4 bertrand 117: COMPLEX*16 TMP
1.1 bertrand 118: *
119: * .. External Functions ..
120: LOGICAL LSAME
121: EXTERNAL LSAME
122: * ..
123: * .. External Subroutines ..
124: EXTERNAL ZSWAP
125: * ..
126: * .. Executable Statements ..
127: *
128: UPPER = LSAME( UPLO, 'U' )
129: IF (UPPER) THEN
130: *
131: * UPPER
132: * first swap
1.10 bertrand 133: * - swap column I1 and I2 from I1 to I1-1
1.1 bertrand 134: CALL ZSWAP( I1-1, A(1,I1), 1, A(1,I2), 1 )
135: *
136: * second swap :
137: * - swap A(I1,I1) and A(I2,I2)
1.10 bertrand 138: * - swap row I1 from I1+1 to I2-1 with col I2 from I1+1 to I2-1
1.1 bertrand 139: TMP=A(I1,I1)
140: A(I1,I1)=A(I2,I2)
141: A(I2,I2)=TMP
142: *
1.13 ! bertrand 143: CALL ZSWAP( I2-I1-1, A(I1,I1+1), LDA, A(I1+1,I2), 1 )
1.1 bertrand 144: *
145: * third swap
146: * - swap row I1 and I2 from I2+1 to N
1.13 ! bertrand 147: IF ( I2.LT.N )
! 148: $ CALL ZSWAP( N-I2, A(I1,I2+1), LDA, A(I2,I2+1), LDA )
1.1 bertrand 149: *
150: ELSE
151: *
152: * LOWER
153: * first swap
1.10 bertrand 154: * - swap row I1 and I2 from I1 to I1-1
1.3 bertrand 155: CALL ZSWAP( I1-1, A(I1,1), LDA, A(I2,1), LDA )
1.1 bertrand 156: *
157: * second swap :
158: * - swap A(I1,I1) and A(I2,I2)
1.10 bertrand 159: * - swap col I1 from I1+1 to I2-1 with row I2 from I1+1 to I2-1
1.1 bertrand 160: TMP=A(I1,I1)
161: A(I1,I1)=A(I2,I2)
162: A(I2,I2)=TMP
163: *
1.13 ! bertrand 164: CALL ZSWAP( I2-I1-1, A(I1+1,I1), 1, A(I2,I1+1), LDA )
1.1 bertrand 165: *
166: * third swap
167: * - swap col I1 and I2 from I2+1 to N
1.13 ! bertrand 168: IF ( I2.LT.N )
! 169: $ CALL ZSWAP( N-I2, A(I2+1,I1), 1, A(I2+1,I2), 1 )
1.1 bertrand 170: *
171: ENDIF
172: END SUBROUTINE ZSYSWAPR
173:
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