TESTING/LIN/sgbt01.f(3)    Library Functions Manual    TESTING/LIN/sgbt01.f(3)

NAME
       TESTING/LIN/sgbt01.f

SYNOPSIS
   Functions/Subroutines
       subroutine sgbt01 (m, n, kl, ku, a, lda, afac, ldafac, ipiv, work,
           resid)
           SGBT01

Function/Subroutine Documentation
   subroutine sgbt01 (integer m, integer n, integer kl, integer ku, real,
       dimension( lda, * ) a, integer lda, real, dimension( ldafac, * ) afac,
       integer ldafac, integer, dimension( * ) ipiv, real, dimension( * )
       work, real resid)
       SGBT01

       Purpose:


           !>
           !> SGBT01 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 REAL 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 REAL 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
           !>          SGBTRF.  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 SGBTRF 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 SGBTRF.
           !>

           WORK

           !>          WORK is REAL array, dimension (2*KL+KU+1)
           !>

           RESID

           !>          RESID is REAL
           !>          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 sgbt01.f.

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

LAPACK                          Version 3.12.0         TESTING/LIN/sgbt01.f(3)