TESTING/LIN/dgtt01.f(3) | Library Functions Manual | TESTING/LIN/dgtt01.f(3) |
NAME
TESTING/LIN/dgtt01.f
SYNOPSIS
Functions/Subroutines
subroutine dgtt01 (n, dl, d, du, dlf, df, duf, du2, ipiv,
work, ldwork, rwork, resid)
DGTT01
Function/Subroutine Documentation
subroutine dgtt01 (integer n, double precision, dimension( * ) dl, double precision, dimension( * ) d, double precision, dimension( * ) du, double precision, dimension( * ) dlf, double precision, dimension( * ) df, double precision, dimension( * ) duf, double precision, dimension( * ) du2, integer, dimension( * ) ipiv, double precision, dimension( ldwork, * ) work, integer ldwork, double precision, dimension( * ) rwork, double precision resid)
DGTT01
Purpose:
DGTT01 reconstructs a tridiagonal matrix A from its LU factorization and computes the residual norm(L*U - A) / ( norm(A) * EPS ), where EPS is the machine epsilon.
Parameters
N
N is INTEGER The order of the matrix A. N >= 0.
DL
DL is DOUBLE PRECISION array, dimension (N-1) The (n-1) sub-diagonal elements of A.
D
D is DOUBLE PRECISION array, dimension (N) The diagonal elements of A.
DU
DU is DOUBLE PRECISION array, dimension (N-1) The (n-1) super-diagonal elements of A.
DLF
DLF is DOUBLE PRECISION array, dimension (N-1) The (n-1) multipliers that define the matrix L from the LU factorization of A.
DF
DF is DOUBLE PRECISION array, dimension (N) The n diagonal elements of the upper triangular matrix U from the LU factorization of A.
DUF
DUF is DOUBLE PRECISION array, dimension (N-1) The (n-1) elements of the first super-diagonal of U.
DU2
DU2 is DOUBLE PRECISION array, dimension (N-2) The (n-2) elements of the second super-diagonal of U.
IPIV
IPIV is INTEGER array, dimension (N) The pivot indices; for 1 <= i <= n, row i of the matrix was interchanged with row IPIV(i). IPIV(i) will always be either i or i+1; IPIV(i) = i indicates a row interchange was not required.
WORK
WORK is DOUBLE PRECISION array, dimension (LDWORK,N)
LDWORK
LDWORK is INTEGER The leading dimension of the array WORK. LDWORK >= max(1,N).
RWORK
RWORK is DOUBLE PRECISION array, dimension (N)
RESID
RESID is DOUBLE PRECISION The scaled residual: norm(L*U - A) / (norm(A) * EPS)
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 132 of file dgtt01.f.
Author
Generated automatically by Doxygen for LAPACK from the source code.
Version 3.12.0 | LAPACK |