
dtpcon.f(3) LAPACK dtpcon.f(3)
NAME
dtpcon.f 
SYNOPSIS
Functions/Subroutines
subroutine dtpcon (NORM, UPLO, DIAG, N, AP, RCOND, WORK, IWORK, INFO)
DTPCON
Function/Subroutine Documentation
subroutine dtpcon (characterNORM, characterUPLO, characterDIAG, integerN, double precision,
dimension( * )AP, double precisionRCOND, double precision, dimension( * )WORK, integer,
dimension( * )IWORK, integerINFO)
DTPCON
Purpose:
DTPCON estimates the reciprocal of the condition number of a packed
triangular matrix A, in either the 1norm or the infinitynorm.
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 1norm condition number or the
infinitynorm condition number is required:
= '1' or 'O': 1norm;
= 'I': Infinitynorm.
UPLO
UPLO is CHARACTER*1
= 'U': A is upper triangular;
= 'L': A is lower triangular.
DIAG
DIAG is CHARACTER*1
= 'N': A is nonunit triangular;
= 'U': A is unit triangular.
N
N is INTEGER
The order of the matrix A. N >= 0.
AP
AP is DOUBLE PRECISION array, dimension (N*(N+1)/2)
The upper or lower triangular matrix A, packed columnwise in
a linear array. The jth column of A is stored in the array
AP as follows:
if UPLO = 'U', AP(i + (j1)*j/2) = A(i,j) for 1<=i<=j;
if UPLO = 'L', AP(i + (j1)*(2nj)/2) = A(i,j) for j<=i<=n.
If DIAG = 'U', the diagonal elements of A are not referenced
and are assumed to be 1.
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 ith argument had an illegal value
Author:
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
November 2011
Definition at line 130 of file dtpcon.f.
Author
Generated automatically by Doxygen for LAPACK from the source code.
Version 3.4.2 Tue Sep 25 2012 dtpcon.f(3) 
