TESTING/LIN/zpbt01.f(3) | Library Functions Manual | TESTING/LIN/zpbt01.f(3) |
NAME
TESTING/LIN/zpbt01.f
SYNOPSIS
Functions/Subroutines
subroutine zpbt01 (uplo, n, kd, a, lda, afac, ldafac,
rwork, resid)
ZPBT01
Function/Subroutine Documentation
subroutine zpbt01 (character uplo, integer n, integer kd, complex*16, dimension( lda, * ) a, integer lda, complex*16, dimension( ldafac, * ) afac, integer ldafac, double precision, dimension( * ) rwork, double precision resid)
ZPBT01
Purpose:
ZPBT01 reconstructs a Hermitian positive definite band matrix A from its L*L' or U'*U factorization and computes the residual norm( L*L' - A ) / ( N * norm(A) * EPS ) or norm( U'*U - A ) / ( N * norm(A) * EPS ), where EPS is the machine epsilon, L' is the conjugate transpose of L, and U' is the conjugate transpose of U.
Parameters
UPLO
UPLO is CHARACTER*1 Specifies whether the upper or lower triangular part of the Hermitian matrix A is stored: = 'U': Upper triangular = 'L': Lower triangular
N
N is INTEGER The number of rows and columns of the matrix A. N >= 0.
KD
KD is INTEGER The number of super-diagonals of the matrix A if UPLO = 'U', or the number of sub-diagonals if UPLO = 'L'. KD >= 0.
A
A is COMPLEX*16 array, dimension (LDA,N) The original Hermitian band matrix A. If UPLO = 'U', the upper triangular part of A is stored as a band matrix; if UPLO = 'L', the lower triangular part of A is stored. The columns of the appropriate triangle are stored in the columns of A and the diagonals of the triangle are stored in the rows of A. See ZPBTRF for further details.
LDA
LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,KD+1).
AFAC
AFAC is COMPLEX*16 array, dimension (LDAFAC,N) The factored form of the matrix A. AFAC contains the factor L or U from the L*L' or U'*U factorization in band storage format, as computed by ZPBTRF.
LDAFAC
LDAFAC is INTEGER The leading dimension of the array AFAC. LDAFAC >= max(1,KD+1).
RWORK
RWORK is DOUBLE PRECISION array, dimension (N)
RESID
RESID is DOUBLE PRECISION If UPLO = 'L', norm(L*L' - A) / ( N * norm(A) * EPS ) If UPLO = 'U', norm(U'*U - A) / ( N * norm(A) * EPS )
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 118 of file zpbt01.f.
Author
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