# zla_porcond_x (3) - Linux Manuals

## NAME

zla_porcond_x.f -

## SYNOPSIS

### Functions/Subroutines

DOUBLE PRECISION function zla_porcond_x (UPLO, N, A, LDA, AF, LDAF, X, INFO, WORK, RWORK)
ZLA_PORCOND_X computes the infinity norm condition number of op(A)*diag(x) for Hermitian positive-definite matrices.

## Function/Subroutine Documentation

### DOUBLE PRECISION function zla_porcond_x (characterUPLO, integerN, complex*16, dimension( lda, * )A, integerLDA, complex*16, dimension( ldaf, * )AF, integerLDAF, complex*16, dimension( * )X, integerINFO, complex*16, dimension( * )WORK, double precision, dimension( * )RWORK)

ZLA_PORCOND_X computes the infinity norm condition number of op(A)*diag(x) for Hermitian positive-definite matrices.

Purpose:

ZLA_PORCOND_X Computes the infinity norm condition number of
op(A) * diag(X) where X is a COMPLEX*16 vector.

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 number of linear equations, i.e., the order of the
matrix A.  N >= 0.

A

A is COMPLEX*16 array, dimension (LDA,N)
On entry, the N-by-N matrix A.

LDA

LDA is INTEGER
The leading dimension of the array A.  LDA >= max(1,N).

AF

AF is COMPLEX*16 array, dimension (LDAF,N)
The triangular factor U or L from the Cholesky factorization
A = U**H*U or A = L*L**H, as computed by ZPOTRF.

LDAF

LDAF is INTEGER
The leading dimension of the array AF.  LDAF >= max(1,N).

X

X is COMPLEX*16 array, dimension (N)
The vector X in the formula op(A) * diag(X).

INFO

INFO is INTEGER
= 0:  Successful exit.
i > 0:  The ith argument is invalid.

WORK

WORK is COMPLEX*16 array, dimension (2*N).
Workspace.

RWORK

RWORK is DOUBLE PRECISION array, dimension (N).
Workspace.

Author:

Univ. of Tennessee

Univ. of California Berkeley