zpbcon.f (3)  Linux Manuals
NAME
zpbcon.f 
SYNOPSIS
Functions/Subroutines
subroutine zpbcon (UPLO, N, KD, AB, LDAB, ANORM, RCOND, WORK, RWORK, INFO)
ZPBCON
Function/Subroutine Documentation
subroutine zpbcon (characterUPLO, integerN, integerKD, complex*16, dimension( ldab, * )AB, integerLDAB, double precisionANORM, double precisionRCOND, complex*16, dimension( * )WORK, double precision, dimension( * )RWORK, integerINFO)
ZPBCON
Purpose:

ZPBCON estimates the reciprocal of the condition number (in the 1norm) of a complex Hermitian positive definite band matrix using the Cholesky factorization A = U**H*U or A = L*L**H computed by ZPBTRF. 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 triangular factor stored in AB; = 'L': Lower triangular factor stored in AB.
NN is INTEGER The order of the matrix A. N >= 0.
KDKD is INTEGER The number of superdiagonals of the matrix A if UPLO = 'U', or the number of subdiagonals if UPLO = 'L'. KD >= 0.
ABAB is COMPLEX*16 array, dimension (LDAB,N) The triangular factor U or L from the Cholesky factorization A = U**H*U or A = L*L**H of the band matrix A, stored in the first KD+1 rows of the array. The jth column of U or L is stored in the jth column of the array AB as follows: if UPLO ='U', AB(kd+1+ij,j) = U(i,j) for max(1,jkd)<=i<=j; if UPLO ='L', AB(1+ij,j) = L(i,j) for j<=i<=min(n,j+kd).
LDABLDAB is INTEGER The leading dimension of the array AB. LDAB >= KD+1.
ANORMANORM is DOUBLE PRECISION The 1norm (or infinitynorm) of the Hermitian band matrix A.
RCONDRCOND 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 1norm of inv(A) computed in this routine.
WORKWORK is COMPLEX*16 array, dimension (2*N)
RWORKRWORK is DOUBLE PRECISION array, dimension (N)
INFOINFO 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 133 of file zpbcon.f.
Author
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