TESTING/LIN/cgtt01.f(3) | Library Functions Manual | TESTING/LIN/cgtt01.f(3) |
NAME
TESTING/LIN/cgtt01.f
SYNOPSIS
Functions/Subroutines
subroutine cgtt01 (n, dl, d, du, dlf, df, duf, du2, ipiv,
work, ldwork, rwork, resid)
CGTT01
Function/Subroutine Documentation
subroutine cgtt01 (integer n, complex, dimension( * ) dl, complex, dimension( * ) d, complex, dimension( * ) du, complex, dimension( * ) dlf, complex, dimension( * ) df, complex, dimension( * ) duf, complex, dimension( * ) du2, integer, dimension( * ) ipiv, complex, dimension( ldwork, * ) work, integer ldwork, real, dimension( * ) rwork, real resid)
CGTT01
Purpose:
CGTT01 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 COMPLEX array, dimension (N-1) The (n-1) sub-diagonal elements of A.
D
D is COMPLEX array, dimension (N) The diagonal elements of A.
DU
DU is COMPLEX array, dimension (N-1) The (n-1) super-diagonal elements of A.
DLF
DLF is COMPLEX array, dimension (N-1) The (n-1) multipliers that define the matrix L from the LU factorization of A.
DF
DF is COMPLEX array, dimension (N) The n diagonal elements of the upper triangular matrix U from the LU factorization of A.
DUF
DUF is COMPLEX array, dimension (N-1) The (n-1) elements of the first super-diagonal of U.
DU2
DU2 is COMPLEX 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 COMPLEX array, dimension (LDWORK,N)
LDWORK
LDWORK is INTEGER The leading dimension of the array WORK. LDWORK >= max(1,N).
RWORK
RWORK is REAL array, dimension (N)
RESID
RESID is REAL 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 cgtt01.f.
Author
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