potri(3)

Library Functions Manual

potri(3)

NAME

potri - potri: triangular inverse

SYNOPSIS

Functions

subroutine cpotri (uplo, n, a, lda, info)
CPOTRI subroutine dpotri (uplo, n, a, lda, info)
DPOTRI subroutine spotri (uplo, n, a, lda, info)
SPOTRI subroutine zpotri (uplo, n, a, lda, info)
ZPOTRI

Detailed Description

Function Documentation

subroutine cpotri (character uplo, integer n, complex, dimension( lda, * ) a, integer lda, integer info)

CPOTRI

Purpose:

!>
!> CPOTRI computes the inverse of a complex Hermitian positive definite
!> matrix A using the Cholesky factorization A = U**H*U or A = L*L**H
!> computed by CPOTRF.
!>

Parameters

UPLO

!>          UPLO is CHARACTER*1
!>          = 'U':  Upper triangle of A is stored;
!>          = 'L':  Lower triangle of A is stored.
!>

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

!>          A is COMPLEX array, dimension (LDA,N)
!>          On entry, the triangular factor U or L from the Cholesky
!>          factorization A = U**H*U or A = L*L**H, as computed by
!>          CPOTRF.
!>          On exit, the upper or lower triangle of the (Hermitian)
!>          inverse of A, overwriting the input factor U or L.
!>

LDA

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

INFO

!>          INFO is INTEGER
!>          = 0:  successful exit
!>          < 0:  if INFO = -i, the i-th argument had an illegal value
!>          > 0:  if INFO = i, the (i,i) element of the factor U or L is
!>                zero, and the inverse could not be computed.
!>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 94 of file cpotri.f.

subroutine dpotri (character uplo, integer n, double precision, dimension( lda, * ) a, integer lda, integer info)

DPOTRI

Purpose:

!>
!> DPOTRI computes the inverse of a real symmetric positive definite
!> matrix A using the Cholesky factorization A = U**T*U or A = L*L**T
!> computed by DPOTRF.
!>

Parameters

UPLO

!>          UPLO is CHARACTER*1
!>          = 'U':  Upper triangle of A is stored;
!>          = 'L':  Lower triangle of A is stored.
!>

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

!>          A is DOUBLE PRECISION array, dimension (LDA,N)
!>          On entry, the triangular factor U or L from the Cholesky
!>          factorization A = U**T*U or A = L*L**T, as computed by
!>          DPOTRF.
!>          On exit, the upper or lower triangle of the (symmetric)
!>          inverse of A, overwriting the input factor U or L.
!>

LDA

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

INFO

!>          INFO is INTEGER
!>          = 0:  successful exit
!>          < 0:  if INFO = -i, the i-th argument had an illegal value
!>          > 0:  if INFO = i, the (i,i) element of the factor U or L is
!>                zero, and the inverse could not be computed.
!>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 94 of file dpotri.f.

subroutine spotri (character uplo, integer n, real, dimension( lda, * ) a, integer lda, integer info)

SPOTRI

Purpose:

!>
!> SPOTRI computes the inverse of a real symmetric positive definite
!> matrix A using the Cholesky factorization A = U**T*U or A = L*L**T
!> computed by SPOTRF.
!>

Parameters

UPLO

!>          UPLO is CHARACTER*1
!>          = 'U':  Upper triangle of A is stored;
!>          = 'L':  Lower triangle of A is stored.
!>

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

!>          A is REAL array, dimension (LDA,N)
!>          On entry, the triangular factor U or L from the Cholesky
!>          factorization A = U**T*U or A = L*L**T, as computed by
!>          SPOTRF.
!>          On exit, the upper or lower triangle of the (symmetric)
!>          inverse of A, overwriting the input factor U or L.
!>

LDA

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

INFO

!>          INFO is INTEGER
!>          = 0:  successful exit
!>          < 0:  if INFO = -i, the i-th argument had an illegal value
!>          > 0:  if INFO = i, the (i,i) element of the factor U or L is
!>                zero, and the inverse could not be computed.
!>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 94 of file spotri.f.

subroutine zpotri (character uplo, integer n, complex16, dimension( lda, ) a, integer lda, integer info)

ZPOTRI

Purpose:

!>
!> ZPOTRI computes the inverse of a complex Hermitian positive definite
!> matrix A using the Cholesky factorization A = U**H*U or A = L*L**H
!> computed by ZPOTRF.
!>

Parameters

UPLO

!>          UPLO is CHARACTER*1
!>          = 'U':  Upper triangle of A is stored;
!>          = 'L':  Lower triangle of A is stored.
!>

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

!>          A is COMPLEX*16 array, dimension (LDA,N)
!>          On entry, the triangular factor U or L from the Cholesky
!>          factorization A = U**H*U or A = L*L**H, as computed by
!>          ZPOTRF.
!>          On exit, the upper or lower triangle of the (Hermitian)
!>          inverse of A, overwriting the input factor U or L.
!>

LDA

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

INFO

!>          INFO is INTEGER
!>          = 0:  successful exit
!>          < 0:  if INFO = -i, the i-th argument had an illegal value
!>          > 0:  if INFO = i, the (i,i) element of the factor U or L is
!>                zero, and the inverse could not be computed.
!>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 94 of file zpotri.f.

Author

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