TESTING/LIN/dgbt01.f(3)    Library Functions Manual    TESTING/LIN/dgbt01.f(3)

NAME
       TESTING/LIN/dgbt01.f

SYNOPSIS
   Functions/Subroutines
       subroutine dgbt01 (m, n, kl, ku, a, lda, afac, ldafac, ipiv, work,
           resid)
           DGBT01

Function/Subroutine Documentation
   subroutine dgbt01 (integer m, integer n, integer kl, integer ku, double
       precision, dimension( lda, * ) a, integer lda, double precision,
       dimension( ldafac, * ) afac, integer ldafac, integer, dimension( * )
       ipiv, double precision, dimension( * ) work, double precision resid)
       DGBT01

       Purpose:


            DGBT01 reconstructs a band matrix A from its L*U factorization and
            computes the residual:
               norm(L*U - A) / ( N * norm(A) * EPS ),
            where EPS is the machine epsilon.

            The expression L*U - A is computed one column at a time, so A and
            AFAC are not modified.

       Parameters
           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.

           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).

           AFAC

                     AFAC is DOUBLE PRECISION array, dimension (LDAFAC,N)
                     The factored form of the matrix A.  AFAC contains the banded
                     factors L and U from the L*U factorization, as computed by
                     DGBTRF.  U is stored as an upper triangular band matrix with
                     KL+KU superdiagonals in rows 1 to KL+KU+1, and the
                     multipliers used during the factorization are stored in rows
                     KL+KU+2 to 2*KL+KU+1.  See DGBTRF for further details.

           LDAFAC

                     LDAFAC is INTEGER
                     The leading dimension of the array AFAC.
                     LDAFAC >= max(1,2*KL*KU+1).

           IPIV

                     IPIV is INTEGER array, dimension (min(M,N))
                     The pivot indices from DGBTRF.

           WORK

                     WORK is DOUBLE PRECISION array, dimension (2*KL+KU+1)

           RESID

                     RESID is DOUBLE PRECISION
                     norm(L*U - A) / ( N * norm(A) * EPS )

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Definition at line 124 of file dgbt01.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0         TESTING/LIN/dgbt01.f(3)