Developer Reference

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

?hptri

Computes the inverse of a complex Hermitian matrix using
U
*
D
*
U
H
or
L
*
D
*
L
H
Bunch-Kaufman factorization of matrix in packed storage.

Syntax

call chptri
(
uplo
,
n
,
ap
,
ipiv
,
work
,
info
)
call zhptri
(
uplo
,
n
,
ap
,
ipiv
,
work
,
info
)
call hptri
(
ap
,
ipiv
[
,
uplo
]
[
,
info
]
)
Include Files
  • mkl.fi
    ,
    lapack.f90
Description
The routine computes the inverse
inv(
A
)
of a complex Hermitian matrix
A
using packed storage. Before calling this routine, call
?hptrf
to factorize
A
.
Input Parameters
uplo
CHARACTER*1
.
Must be
'U'
or
'L'
.
Indicates how the input matrix
A
has been factored:
If
uplo
=
'U'
, the array
ap
stores the packed Bunch-Kaufman factorization
A
=
U*D*U
H
.
If
uplo
=
'L'
, the array
ap
stores the packed Bunch-Kaufman factorization
A
=
L*D*L
H
.
n
INTEGER
.
The order of the matrix
A
;
n
0
.
ap
,
work
COMPLEX
for
chptri
DOUBLE COMPLEX
for
zhptri
.
Arrays:
ap
(*)
contains the factorization of the matrix
A
, as returned by
?hptrf
.
The dimension of
ap
must be at least
max(1,
n
(
n
+1)/2)
.
work
(*)
is a workspace array.
The dimension of
work
must be at least
max(1,
n
)
.
ipiv
INTEGER
.
Array, size at least
max(1,
n
)
.
The
ipiv
array, as returned by
?hptrf
.
Output Parameters
ap
Overwritten by the matrix
inv(
A
)
.
info
INTEGER
.
If
info
= 0
, the execution is successful.
If
info
=
-i
, the
i
-th parameter had an illegal value.
If
info
=
i
, the
i
-th diagonal element of
D
is zero,
D
is singular, and the inversion could not be completed.
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
hptri
interface are as follows:
ap
Holds the array
A
of size (
n
*(
n
+1)/2
).
ipiv
Holds the vector of length
n
.
uplo
Must be
'U'
or
'L'
. The default value is
'U'
.
Application Notes