Annotation of rpl/lapack/lapack/zheswapr.f, revision 1.2
1.2 ! bertrand 1: *> \brief \b ZHESWAPR
! 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 November 2011
! 99: *
! 100: *> \ingroup complex16HEauxiliary
! 101: *
! 102: * =====================================================================
1.1 bertrand 103: SUBROUTINE ZHESWAPR( UPLO, N, A, LDA, I1, I2)
104: *
1.2 ! bertrand 105: * -- LAPACK auxiliary routine (version 3.4.0) --
1.1 bertrand 106: * -- LAPACK is a software package provided by Univ. of Tennessee, --
107: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
1.2 ! bertrand 108: * November 2011
1.1 bertrand 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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