
ZSPCON(l) ) ZSPCON(l)
NAME
ZSPCON  estimate the reciprocal of the condition number (in the 1norm) of a complex sym
metric packed matrix A using the factorization A = U*D*U**T or A = L*D*L**T computed by
ZSPTRF
SYNOPSIS
SUBROUTINE ZSPCON( UPLO, N, AP, IPIV, ANORM, RCOND, WORK, INFO )
CHARACTER UPLO
INTEGER INFO, N
DOUBLE PRECISION ANORM, RCOND
INTEGER IPIV( * )
COMPLEX*16 AP( * ), WORK( * )
PURPOSE
ZSPCON estimates the reciprocal of the condition number (in the 1norm) of a complex sym
metric packed matrix A using the factorization A = U*D*U**T or A = L*D*L**T computed by
ZSPTRF. An estimate is obtained for norm(inv(A)), and the reciprocal of the condition
number is computed as RCOND = 1 / (ANORM * norm(inv(A))).
ARGUMENTS
UPLO (input) 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 (input) INTEGER
The order of the matrix A. N >= 0.
AP (input) COMPLEX*16 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 ZSPTRF, stored as a packed triangular matrix.
IPIV (input) INTEGER array, dimension (N)
Details of the interchanges and the block structure of D as determined by ZSPTRF.
ANORM (input) DOUBLE PRECISION
The 1norm of the original matrix A.
RCOND (output) 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 1norm of inv(A) computed
in this routine.
WORK (workspace) COMPLEX*16 array, dimension (2*N)
INFO (output) INTEGER
= 0: successful exit
< 0: if INFO = i, the ith argument had an illegal value
LAPACK version 3.0 15 June 2000 ZSPCON(l) 
