Developer Reference

  • 2020.2
  • 07/15/2020
  • Public Content
Contents

?syswapr

Applies an elementary permutation on the rows and columns of a symmetric matrix.

Syntax

call ssyswapr
(
uplo
,
n
,
a
,
lda
,
i1
,
i2
)
call dsyswapr
(
uplo
,
n
,
a
,
lda
,
i1
,
i2
)
call csyswapr
(
uplo
,
n
,
a
,
lda
,
i1
,
i2
)
call zsyswapr
(
uplo
,
n
,
a
,
lda
,
i1
,
i2
)
call syswapr
(
a
,
i1
,
i2
[
,
uplo
]
)
Include Files
  • mkl.fi
    ,
    lapack.f90
Description
The routine applies an elementary permutation on the rows and columns of a symmetric matrix.
Input Parameters
The data types are given for the Fortran interface.
uplo
CHARACTER*1
.
Must be
'U'
or
'L'
.
Indicates how the input matrix
A
has been factored:
If
uplo
=
'U'
, the array
a
stores the upper triangular factor
U
of the factorization
A
=
U*D*U
T
.
If
uplo
=
'L'
, the array
a
stores the lower triangular factor
L
of the factorization
A
=
L*D*L
T
.
n
INTEGER
.
The order of matrix
A
;
n
0.
nrhs
INTEGER
.
The number of right-hand sides;
nrhs
0.
a
REAL
for
ssyswapr
DOUBLE PRECISION
for
dsyswapr
COMPLEX
for
csyswapr
DOUBLE COMPLEX
for
zsyswapr
Array of size
(
lda
,
n
)
.
The array
a
contains the block diagonal matrix
D
and the multipliers used to obtain the factor
U
or
L
as computed by
?sytrf
.
lda
INTEGER
. The leading dimension of the array
a
.
lda
max
(1,
n
).
i1
INTEGER
.
Index of the first row to swap.
i2
INTEGER
.
Index of the second row to swap.
Output Parameters
a
If
info
= 0
, the symmetric inverse of the original matrix.
If
info
=
'U'
, the upper triangular part of the inverse is formed and the part of
A
below the diagonal is not referenced.
If
info
=
'L'
, the lower triangular part of the inverse is formed and the part of
A
above the diagonal is not referenced.
LAPACK 95 Interface Notes
Routines in Fortran 95 interface have fewer arguments in the calling sequence than their FORTRAN 77 counterparts. For general conventions applied to skip redundant or reconstructible arguments, see LAPACK 95 Interface Conventions.
Specific details for the routine
syswapr
interface are as follows:
a
Holds the matrix
A
of size (
n
,
n
).
i1
Holds the index for swap.
i2
Holds the index for swap.
uplo
Indicates how the matrix
A
has been factored. Must be
'U'
or
'L'
.