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SRC/zla_syrpvgrw.f(3) LAPACK SRC/zla_syrpvgrw.f(3)

SRC/zla_syrpvgrw.f


double precision function zla_syrpvgrw (uplo, n, info, a, lda, af, ldaf, ipiv, work)
ZLA_SYRPVGRW computes the reciprocal pivot growth factor norm(A)/norm(U) for a symmetric indefinite matrix.

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.

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 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 DOUBLE PRECISION array, dimension (2*N)

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 121 of file zla_syrpvgrw.f.

Generated automatically by Doxygen for LAPACK from the source code.

Sun Jan 12 2025 15:13:32 Version 3.12.1

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