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/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dtrcon.f(3) Library Functions Manual /home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dtrcon.f(3)

NAME

/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dtrcon.f

SYNOPSIS

Functions/Subroutines


subroutine DTRCON (norm, uplo, diag, n, a, lda, rcond, work, iwork, info)
DTRCON

Function/Subroutine Documentation

subroutine DTRCON (character norm, character uplo, character diag, integer n, double precision, dimension( lda, * ) a, integer lda, double precision rcond, double precision, dimension( * ) work, integer, dimension( * ) iwork, integer info)

DTRCON

Purpose:

!>
!> DTRCON estimates the reciprocal of the condition number of a
!> triangular matrix A, in either the 1-norm or the infinity-norm.
!>
!> The norm of A is computed and an estimate is obtained for
!> norm(inv(A)), then the reciprocal of the condition number is
!> computed as
!>    RCOND = 1 / ( norm(A) * norm(inv(A)) ).
!> 

Parameters

NORM

!>          NORM is CHARACTER*1
!>          Specifies whether the 1-norm condition number or the
!>          infinity-norm condition number is required:
!>          = '1' or 'O':  1-norm;
!>          = 'I':         Infinity-norm.
!> 

UPLO

!>          UPLO is CHARACTER*1
!>          = 'U':  A is upper triangular;
!>          = 'L':  A is lower triangular.
!> 

DIAG

!>          DIAG is CHARACTER*1
!>          = 'N':  A is non-unit triangular;
!>          = 'U':  A is unit triangular.
!> 

N

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

A

!>          A is DOUBLE PRECISION array, dimension (LDA,N)
!>          The triangular matrix A.  If UPLO = 'U', the leading N-by-N
!>          upper triangular part of the array A contains the upper
!>          triangular matrix, and the strictly lower triangular part of
!>          A is not referenced.  If UPLO = 'L', the leading N-by-N lower
!>          triangular part of the array A contains the lower triangular
!>          matrix, and the strictly upper triangular part of A is not
!>          referenced.  If DIAG = 'U', the diagonal elements of A are
!>          also not referenced and are assumed to be 1.
!> 

LDA

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

RCOND

!>          RCOND is DOUBLE PRECISION
!>          The reciprocal of the condition number of the matrix A,
!>          computed as RCOND = 1/(norm(A) * norm(inv(A))).
!> 

WORK

!>          WORK is DOUBLE PRECISION array, dimension (3*N)
!> 

IWORK

!>          IWORK is INTEGER array, dimension (N)
!> 

INFO

!>          INFO is INTEGER
!>          = 0:  successful exit
!>          < 0:  if INFO = -i, the i-th argument had an illegal value
!> 

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 135 of file dtrcon.f.

Author

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Version 3.12.0 LAPACK