cgtt023
Part of cgtt02.f(3).
Usage
Functions/Subroutines
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.