DOUBLE PRECISION function zla_syrpvgrw (UPLO, N, INFO, A, LDA, AF, LDAF, IPIV, WORK)
DOUBLE PRECISION function zla_syrpvgrw (character*1UPLO, integerN, integerINFO, complex*16, dimension( lda, * )A, integerLDA, complex*16, dimension( ldaf, * )AF, integerLDAF, integer, dimension( * )IPIV, double precision, dimension( * )WORK)ZLA_SYRPVGRW computes the reciprocal pivot growth factor norm(A)/norm(U) for a symmetric indefinite matrix. Purpose:
ZLA_SYRPVGRW 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.
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 ZSYTRF, .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 ZSYTRF.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 ZSYTRF.WORK
WORK is COMPLEX*16 array, dimension (2*N)
Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd.Date:
September 2012Definition at line 123 of file zla_syrpvgrw.f.