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

NAME

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

SYNOPSIS

Functions/Subroutines


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

Function/Subroutine Documentation

subroutine SPPCON (character uplo, integer n, real, dimension( * ) ap, real anorm, real rcond, real, dimension( * ) work, integer, dimension( * ) iwork, integer info)

SPPCON

Purpose:

!>
!> SPPCON estimates the reciprocal of the condition number (in the
!> 1-norm) of a real symmetric positive definite packed matrix using
!> the Cholesky factorization A = U**T*U or A = L*L**T computed by
!> SPPTRF.
!>
!> 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
!>          = 'U':  Upper triangle of A is stored;
!>          = 'L':  Lower triangle of A is stored.
!> 

N

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

AP

!>          AP is REAL array, dimension (N*(N+1)/2)
!>          The triangular factor U or L from the Cholesky factorization
!>          A = U**T*U or A = L*L**T, packed columnwise in a linear
!>          array.  The j-th column of U or L is stored in the array AP
!>          as follows:
!>          if UPLO = 'U', AP(i + (j-1)*j/2) = U(i,j) for 1<=i<=j;
!>          if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = L(i,j) for j<=i<=n.
!> 

ANORM

!>          ANORM is REAL
!>          The 1-norm (or infinity-norm) of the symmetric matrix A.
!> 

RCOND

!>          RCOND is REAL
!>          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 REAL 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 117 of file sppcon.f.

Author

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Version 3.12.0 LAPACK