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

NAME

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

SYNOPSIS

Functions/Subroutines


subroutine DSPCON (uplo, n, ap, ipiv, anorm, rcond, work, iwork, info)
DSPCON

Function/Subroutine Documentation

subroutine DSPCON (character uplo, integer n, double precision, dimension( * ) ap, integer, dimension( * ) ipiv, double precision anorm, double precision rcond, double precision, dimension( * ) work, integer, dimension( * ) iwork, integer info)

DSPCON

Purpose:

!>
!> DSPCON estimates the reciprocal of the condition number (in the
!> 1-norm) of a real symmetric packed matrix A using the factorization
!> A = U*D*U**T or A = L*D*L**T computed by DSPTRF.
!>
!> An estimate is obtained for norm(inv(A)), and the reciprocal of the
!> condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))).
!> 

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.
!> 

AP

!>          AP is DOUBLE PRECISION array, dimension (N*(N+1)/2)
!>          The block diagonal matrix D and the multipliers used to
!>          obtain the factor U or L as computed by DSPTRF, stored as a
!>          packed triangular matrix.
!> 

IPIV

!>          IPIV is INTEGER array, dimension (N)
!>          Details of the interchanges and the block structure of D
!>          as determined by DSPTRF.
!> 

ANORM

!>          ANORM is DOUBLE PRECISION
!>          The 1-norm of the original matrix A.
!> 

RCOND

!>          RCOND is DOUBLE PRECISION
!>          The reciprocal of the condition number of the matrix A,
!>          computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is an
!>          estimate of the 1-norm of inv(A) computed in this routine.
!> 

WORK

!>          WORK is DOUBLE PRECISION array, dimension (2*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 123 of file dspcon.f.

Author

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Version 3.12.0 LAPACK