# zla_herpvgrw.f - Man Page

## Synopsis

### Functions/Subroutines

double precision function **zla_herpvgrw** (UPLO, **N**, INFO, A, **LDA**, AF, LDAF, IPIV, WORK)**ZLA_HERPVGRW**

## Function/Subroutine Documentation

### double precision function zla_herpvgrw (character*1 UPLO, integer N, integer INFO, complex*16, dimension( lda, * ) A, integer LDA, complex*16, dimension( ldaf, * ) AF, integer LDAF, integer, dimension( * ) IPIV, double precision, dimension( * ) WORK)

**ZLA_HERPVGRW**

**Purpose:**

ZLA_HERPVGRW computes the reciprocal pivot growth factor norm(A)/norm(U). The "max absolute element" norm is used. If this is much less than 1, the stability of the LU factorization of the (equilibrated) matrix A could be poor. This also means that the solution X, estimated condition numbers, and error bounds could be unreliable.

**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.

*INFO*INFO is INTEGER The value of INFO returned from ZHETRF, .i.e., the pivot in column INFO is exactly 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 block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by ZHETRF.

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

*IPIV*IPIV is INTEGER array, dimension (N) Details of the interchanges and the block structure of D as determined by ZHETRF.

*WORK*WORK is DOUBLE PRECISION array, dimension (2*N)

**Author:**Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

**Date:**June 2016

Definition at line 125 of file zla_herpvgrw.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page zla_herpvgrw(3) is an alias of zla_herpvgrw.f(3).

Tue Nov 14 2017 Version 3.8.0 LAPACK