# sla_porpvgrw.f - Man Page

SRC/sla_porpvgrw.f

## Synopsis

### Functions/Subroutines

real function sla_porpvgrw (uplo, ncols, a, lda, af, ldaf, work)
SLA_PORPVGRW computes the reciprocal pivot growth factor norm(A)/norm(U) for a symmetric or Hermitian positive-definite matrix.

## Function/Subroutine Documentation

### real function sla_porpvgrw (character*1 uplo, integer ncols, real, dimension( lda, * ) a, integer lda, real, dimension( ldaf, * ) af, integer ldaf, real, dimension( * ) work)

SLA_PORPVGRW computes the reciprocal pivot growth factor norm(A)/norm(U) for a symmetric or Hermitian positive-definite matrix.

Purpose:

``` SLA_PORPVGRW 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.```

NCOLS

```          NCOLS is INTEGER
The number of columns of the matrix A. NCOLS >= 0.```

A

```          A is REAL 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 REAL array, dimension (LDAF,N)
The triangular factor U or L from the Cholesky factorization
A = U**T*U or A = L*L**T, as computed by SPOTRF.```

LDAF

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

WORK

`          WORK is REAL array, dimension (2*N)`
Author

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Definition at line 103 of file sla_porpvgrw.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

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

Tue Nov 28 2023 12:08:42 Version 3.12.0 LAPACK