SRC/cla_gbrpvgrw.f(3)      Library Functions Manual      SRC/cla_gbrpvgrw.f(3)

NAME
       SRC/cla_gbrpvgrw.f

SYNOPSIS
   Functions/Subroutines
       real function cla_gbrpvgrw (n, kl, ku, ncols, ab, ldab, afb, ldafb)
           CLA_GBRPVGRW computes the reciprocal pivot growth factor
           norm(A)/norm(U) for a general banded matrix.

Function/Subroutine Documentation
   real function cla_gbrpvgrw (integer n, integer kl, integer ku, integer
       ncols, complex, dimension( ldab, * ) ab, integer ldab, complex,
       dimension( ldafb, * ) afb, integer ldafb)
       CLA_GBRPVGRW computes the reciprocal pivot growth factor
       norm(A)/norm(U) for a general banded matrix.

       Purpose:


           !>
           !> CLA_GBRPVGRW computes the reciprocal pivot growth factor
           !> norm(A)/norm(U). The  norm is used. If this is
           !> much less than 1, the stability of the LU factorization of the
           !> (equilibrated) matrix A could be poor. This also means that the
           !> solution X, estimated condition numbers, and error bounds could be
           !> unreliable.
           !>

       Parameters
           N

           !>          N is INTEGER
           !>     The number of linear equations, i.e., the order 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.
           !>

           NCOLS

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

           AB

           !>          AB is COMPLEX array, dimension (LDAB,N)
           !>     On entry, the matrix A in band storage, in rows 1 to KL+KU+1.
           !>     The j-th column of A is stored in the j-th column of the
           !>     array AB as follows:
           !>     AB(KU+1+i-j,j) = A(i,j) for max(1,j-KU)<=i<=min(N,j+kl)
           !>

           LDAB

           !>          LDAB is INTEGER
           !>     The leading dimension of the array AB.  LDAB >= KL+KU+1.
           !>

           AFB

           !>          AFB is COMPLEX array, dimension (LDAFB,N)
           !>     Details of the LU factorization of the band matrix A, as
           !>     computed by CGBTRF.  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.
           !>

           LDAFB

           !>          LDAFB is INTEGER
           !>     The leading dimension of the array AFB.  LDAFB >= 2*KL+KU+1.
           !>

       Author
           Univ. of Tennessee


           Univ. of California Berkeley


           Univ. of Colorado Denver


           NAG Ltd.

       Definition at line 115 of file cla_gbrpvgrw.f.

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

LAPACK                          Version 3.12.0           SRC/cla_gbrpvgrw.f(3)