dspcon.f

Section: LAPACK (3)
Updated: Tue Nov 14 2017
Page Index
 

NAME

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.

Date:

December 2016

Definition at line 127 of file dspcon.f.  

Author

Generated automatically by Doxygen for LAPACK from the source code.


 

Index

NAME
SYNOPSIS
Functions/Subroutines
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)
Author
LinuxReviews : manual page archive : man3