LAPACK 3.11.0
LAPACK: Linear Algebra PACKage
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◆ zheswapr()

subroutine zheswapr ( character  UPLO,
integer  N,
complex*16, dimension( lda, n )  A,
integer  LDA,
integer  I1,
integer  I2 
)

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

Download ZHESWAPR + dependencies [TGZ] [ZIP] [TXT]

Purpose:
 ZHESWAPR 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*16 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
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.

Definition at line 101 of file zheswapr.f.

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
logical function lsame(CA, CB)
LSAME
Definition: lsame.f:53
subroutine zswap(N, ZX, INCX, ZY, INCY)
ZSWAP
Definition: zswap.f:81
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