# zhetri2.f(3) [centos man page]

```zhetri2.f(3)							      LAPACK							      zhetri2.f(3)

NAME
zhetri2.f -

SYNOPSIS
Functions/Subroutines
subroutine zhetri2 (UPLO, N, A, LDA, IPIV, WORK, LWORK, INFO)
ZHETRI2

Function/Subroutine Documentation
subroutine zhetri2 (characterUPLO, integerN, complex*16, dimension( lda, * )A, integerLDA, integer, dimension( * )IPIV, complex*16, dimension(
* )WORK, integerLWORK, integerINFO)
ZHETRI2

Purpose:

ZHETRI2 computes the inverse of a COMPLEX*16 hermitian indefinite matrix
A using the factorization A = U*D*U**T or A = L*D*L**T computed by
ZHETRF. ZHETRI2 set the LEADING DIMENSION of the workspace
before calling ZHETRI2X that actually computes the inverse.

Parameters:
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.

N

N is INTEGER
The order of the matrix A.  N >= 0.

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 ZHETRF.

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.

LDA

LDA is INTEGER
The leading dimension of the array A.  LDA >= max(1,N).

IPIV

IPIV is INTEGER array, dimension (N)
Details of the interchanges and the NB structure of D
as determined by ZHETRF.

WORK

WORK is COMPLEX*16 array, dimension (N+NB+1)*(NB+3)

LWORK

LWORK is INTEGER
The dimension of the array WORK.
WORK is size >= (N+NB+1)*(NB+3)
If LDWORK = -1, then a workspace query is assumed; the routine
calculates:
- the optimal size of the WORK array, returns
this value as the first entry of the WORK array,
- and no error message related to LDWORK is issued by XERBLA.

INFO

INFO is INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
> 0: if INFO = i, D(i,i) = 0; the matrix is singular and its
inverse could not be computed.

Author:
Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Date:
November 2011

Definition at line 128 of file zhetri2.f.

Author
Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.2							  Tue Sep 25 2012						      zhetri2.f(3)```

## Check Out this Related Man Page

```zhetri2.f(3)							      LAPACK							      zhetri2.f(3)

NAME
zhetri2.f -

SYNOPSIS
Functions/Subroutines
subroutine zhetri2 (UPLO, N, A, LDA, IPIV, WORK, LWORK, INFO)
ZHETRI2

Function/Subroutine Documentation
subroutine zhetri2 (characterUPLO, integerN, complex*16, dimension( lda, * )A, integerLDA, integer, dimension( * )IPIV, complex*16, dimension(
* )WORK, integerLWORK, integerINFO)
ZHETRI2

Purpose:

ZHETRI2 computes the inverse of a COMPLEX*16 hermitian indefinite matrix
A using the factorization A = U*D*U**T or A = L*D*L**T computed by
ZHETRF. ZHETRI2 set the LEADING DIMENSION of the workspace
before calling ZHETRI2X that actually computes the inverse.

Parameters:
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.

N

N is INTEGER
The order of the matrix A.  N >= 0.

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 ZHETRF.

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.

LDA

LDA is INTEGER
The leading dimension of the array A.  LDA >= max(1,N).

IPIV

IPIV is INTEGER array, dimension (N)
Details of the interchanges and the NB structure of D
as determined by ZHETRF.

WORK

WORK is COMPLEX*16 array, dimension (N+NB+1)*(NB+3)

LWORK

LWORK is INTEGER
The dimension of the array WORK.
WORK is size >= (N+NB+1)*(NB+3)
If LDWORK = -1, then a workspace query is assumed; the routine
calculates:
- the optimal size of the WORK array, returns
this value as the first entry of the WORK array,
- and no error message related to LDWORK is issued by XERBLA.

INFO

INFO is INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
> 0: if INFO = i, D(i,i) = 0; the matrix is singular and its
inverse could not be computed.

Author:
Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Date:
November 2011

Definition at line 128 of file zhetri2.f.

Author
Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.1							  Sun May 26 2013						      zhetri2.f(3)```
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