zla_gbrpvgrw.f - Man Page
Synopsis
Functions/Subroutines
double precision function zla_gbrpvgrw (N, KL, KU, NCOLS, AB, LDAB, AFB, LDAFB)
ZLA_GBRPVGRW computes the reciprocal pivot growth factor norm(A)/norm(U) for a general banded matrix.
Function/Subroutine Documentation
double precision function zla_gbrpvgrw (integer N, integer KL, integer KU, integer NCOLS, complex*16, dimension( ldab, * ) AB, integer LDAB, complex*16, dimension( ldafb, * ) AFB, integer LDAFB)
ZLA_GBRPVGRW computes the reciprocal pivot growth factor norm(A)/norm(U) for a general banded matrix.
Purpose:
ZLA_GBRPVGRW 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:
N
N is INTEGER The number of linear equations, i.e., the order of the matrix A. N >= 0.
KL
KL is INTEGER The number of subdiagonals within the band of A. KL >= 0.
KU
KU is INTEGER The number of superdiagonals within the band of A. KU >= 0.
NCOLS
NCOLS is INTEGER The number of columns of the matrix A. NCOLS >= 0.
AB
AB is COMPLEX*16 array, dimension (LDAB,N) On entry, the matrix A in band storage, in rows 1 to KL+KU+1. The j-th column of A is stored in the j-th column of the array AB as follows: AB(KU+1+i-j,j) = A(i,j) for max(1,j-KU)<=i<=min(N,j+kl)
LDAB
LDAB is INTEGER The leading dimension of the array AB. LDAB >= KL+KU+1.
AFB
AFB is COMPLEX*16 array, dimension (LDAFB,N) Details of the LU factorization of the band matrix A, as computed by ZGBTRF. U is stored as an upper triangular band matrix with KL+KU superdiagonals in rows 1 to KL+KU+1, and the multipliers used during the factorization are stored in rows KL+KU+2 to 2*KL+KU+1.
LDAFB
LDAFB is INTEGER The leading dimension of the array AFB. LDAFB >= 2*KL+KU+1.
- Author:
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
- Date:
December 2016
Definition at line 119 of file zla_gbrpvgrw.f.
Author
Generated automatically by Doxygen for LAPACK from the source code.
Referenced By
The man page zla_gbrpvgrw(3) is an alias of zla_gbrpvgrw.f(3).
Tue Nov 14 2017 Version 3.8.0 LAPACK