!>
!> DGBT02 computes the residual for a solution of a banded system of
!> equations op(A)*X = B:
!>    RESID = norm(B - op(A)*X) / ( norm(op(A)) * norm(X) * EPS ),
!> where op(A) = A or A**T, depending on TRANS, and EPS is the
!> machine epsilon.
!> The norm used is the 1-norm.
!> 

TRANS

!>          TRANS is CHARACTER*1
!>          Specifies the form of the system of equations:
!>          = 'N':  A    * X = B  (No transpose)
!>          = 'T':  A**T * X = B  (Transpose)
!>          = 'C':  A**H * X = B  (Conjugate transpose = Transpose)
!> 

M

!>          M is INTEGER
!>          The number of rows of the matrix A.  M >= 0.
!> 

N

!>          N is INTEGER
!>          The number of columns of the matrix A.  N >= 0.
!> 

KL

!>          KL is INTEGER
!>          The number of subdiagonals within the band of A.  KL >= 0.
!> 

KU

!>          KU is INTEGER
!>          The number of superdiagonals within the band of A.  KU >= 0.
!> 

NRHS

!>          NRHS is INTEGER
!>          The number of columns of B.  NRHS >= 0.
!> 

A

!>          A is DOUBLE PRECISION array, dimension (LDA,N)
!>          The original matrix A in band storage, stored in rows 1 to
!>          KL+KU+1.
!> 

LDA

!>          LDA is INTEGER
!>          The leading dimension of the array A.  LDA >= max(1,KL+KU+1).
!> 

X

!>          X is DOUBLE PRECISION array, dimension (LDX,NRHS)
!>          The computed solution vectors for the system of linear
!>          equations.
!> 

LDX

!>          LDX is INTEGER
!>          The leading dimension of the array X.  If TRANS = 'N',
!>          LDX >= max(1,N); if TRANS = 'T' or 'C', LDX >= max(1,M).
!> 

B

!>          B is DOUBLE PRECISION 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 - A*X.
!> 

LDB

!>          LDB is INTEGER
!>          The leading dimension of the array B.  IF TRANS = 'N',
!>          LDB >= max(1,M); if TRANS = 'T' or 'C', LDB >= max(1,N).
!> 

RWORK

!>          RWORK is DOUBLE PRECISION array, dimension (MAX(1,LRWORK)),
!>          where LRWORK >= M when TRANS = 'T' or 'C'; otherwise, RWORK
!>          is not referenced.
!> 

RESID

!>          RESID is DOUBLE PRECISION
!>          The maximum over the number of right hand sides of
!>          norm(B - op(A)*X) / ( norm(op(A)) * norm(X) * EPS ).
!> 

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.