Provided by: liblapack-doc-man_3.5.0-2ubuntu1_all
NAME
dla_porpvgrw.f -
SYNOPSIS
Functions/Subroutines double precision function dla_porpvgrw (UPLO, NCOLS, A, LDA, AF, LDAF, WORK) DLA_PORPVGRW computes the reciprocal pivot growth factor norm(A)/norm(U) for a symmetric or Hermitian positive-definite matrix.
Function/Subroutine Documentation
double precision function dla_porpvgrw (character*1UPLO, integerNCOLS, double precision, dimension( lda, * )A, integerLDA, double precision, dimension( ldaf, * )AF, integerLDAF, double precision, dimension( * )WORK) DLA_PORPVGRW computes the reciprocal pivot growth factor norm(A)/norm(U) for a symmetric or Hermitian positive-definite matrix. Purpose: DLA_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 DOUBLE PRECISION 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 DOUBLE PRECISION 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 DPOTRF. LDAF LDAF is INTEGER The leading dimension of the array AF. LDAF >= max(1,N). WORK WORK is DOUBLE PRECISION array, dimension (2*N) Author: Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. Date: September 2012 Definition at line 106 of file dla_porpvgrw.f.
Author
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