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

NAME
       SRC/zla_gbrpvgrw.f

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

Function/Subroutine Documentation
   double precision function zla_gbrpvgrw (integer n, integer kl, integer ku,
       integer ncols, complex*16, dimension( ldab, * ) ab, integer ldab,
       complex*16, dimension( ldafb, * ) afb, integer ldafb)
       ZLA_GBRPVGRW computes the reciprocal pivot growth factor
       norm(A)/norm(U) for a general banded matrix.

       Purpose:


            ZLA_GBRPVGRW computes the reciprocal pivot growth factor
            norm(A)/norm(U). The 'max absolute element' 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*16 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*16 array, dimension (LDAFB,N)
                Details of the LU factorization of the band matrix A, as
                computed by ZGBTRF.  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 zla_gbrpvgrw.f.

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

LAPACK                          Version 3.12.0           SRC/zla_gbrpvgrw.f(3)