LAPACK  3.6.1 LAPACK: Linear Algebra PACKage
 subroutine cheswapr ( character UPLO, integer N, complex, dimension( lda, n ) A, integer LDA, integer I1, integer I2 )

CHESWAPR applies an elementary permutation on the rows and columns of a Hermitian matrix.

Purpose:
``` CHESWAPR applies an elementary permutation on the rows and the columns of
a hermitian matrix.```
Parameters
 [in] UPLO ``` 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.``` [in] N ``` N is INTEGER The order of the matrix A. N >= 0.``` [in,out] A ``` A is COMPLEX 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 CSYTRF. 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.``` [in] LDA ``` LDA is INTEGER The leading dimension of the array A. LDA >= max(1,N).``` [in] I1 ``` I1 is INTEGER Index of the first row to swap``` [in] I2 ``` I2 is INTEGER Index of the second row to swap```
Date
September 2012

Definition at line 104 of file cheswapr.f.

104 *
105 * -- LAPACK auxiliary routine (version 3.4.2) --
106 * -- LAPACK is a software package provided by Univ. of Tennessee, --
107 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
108 * September 2012
109 *
110 * .. Scalar Arguments ..
111  CHARACTER uplo
112  INTEGER i1, i2, lda, n
113 * ..
114 * .. Array Arguments ..
115  COMPLEX a( lda, n )
116 *
117 * =====================================================================
118 *
119 * ..
120 * .. Local Scalars ..
121  LOGICAL upper
122  INTEGER i
123  COMPLEX tmp
124 *
125 * .. External Functions ..
126  LOGICAL lsame
127  EXTERNAL lsame
128 * ..
129 * .. External Subroutines ..
130  EXTERNAL cswap
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 cswap( 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)=conjg(a(i1+i,i2))
154  a(i1+i,i2)=conjg(tmp)
155  END DO
156 *
157  a(i1,i2)=conjg(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 cswap ( 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)=conjg(a(i2,i1+i))
187  a(i2,i1+i)=conjg(tmp)
188  END DO
189 *
190  a(i2,i1)=conjg(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
subroutine cswap(N, CX, INCX, CY, INCY)
CSWAP
Definition: cswap.f:52
logical function lsame(CA, CB)
LSAME
Definition: lsame.f:55

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