TESTING/LIN/cgtt02.f(3) | Library Functions Manual | TESTING/LIN/cgtt02.f(3) |
NAME
TESTING/LIN/cgtt02.f
SYNOPSIS
Functions/Subroutines
subroutine cgtt02 (trans, n, nrhs, dl, d, du, x, ldx, b,
ldb, resid)
CGTT02
Function/Subroutine Documentation
subroutine cgtt02 (character trans, integer n, integer nrhs, complex, dimension( * ) dl, complex, dimension( * ) d, complex, dimension( * ) du, complex, dimension( ldx, * ) x, integer ldx, complex, dimension( ldb, * ) b, integer ldb, real resid)
CGTT02
Purpose:
CGTT02 computes the residual for the solution to a tridiagonal system of equations: RESID = norm(B - op(A)*X) / (norm(op(A)) * norm(X) * EPS), where EPS is the machine epsilon.
Parameters
TRANS
TRANS is CHARACTER Specifies the form of the residual. = 'N': B - A * X (No transpose) = 'T': B - A**T * X (Transpose) = 'C': B - A**H * X (Conjugate transpose)
N
N is INTEGER The order of the matrix A. N >= 0.
NRHS
NRHS is INTEGER The number of right hand sides, i.e., the number of columns of the matrices B and X. NRHS >= 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.
X
X is COMPLEX array, dimension (LDX,NRHS) The computed solution vectors X.
LDX
LDX is INTEGER The leading dimension of the array X. LDX >= max(1,N).
B
B is COMPLEX array, dimension (LDB,NRHS) On entry, the right hand side vectors for the system of linear equations. On exit, B is overwritten with the difference B - op(A)*X.
LDB
LDB is INTEGER The leading dimension of the array B. LDB >= max(1,N).
RESID
RESID is REAL norm(B - op(A)*X) / (norm(op(A)) * norm(X) * EPS)
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 122 of file cgtt02.f.
Author
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