dla_gbrpvgrw.f(3)

NAME
dla_gbrpvgrw.f -

SYNOPSIS

  Functions/Subroutines
DOUBLE PRECISION function DLA_GBRPVGRW (N, KL, KU, NCOLS, AB, LDAB, AFB, LDAFB)
DLA_GBRPVGRW

Function/Subroutine Documentation

  DOUBLE PRECISION function DLA_GBRPVGRW (INTEGERN, INTEGERKL, INTEGERKU, INTEGERNCOLS, DOUBLE PRECISION, dimension( ldab, * )AB, INTEGERLDAB, DOUBLE PRECISION, dimension( ldafb, * )AFB, INTEGERLDAFB)

DLA_GBRPVGRW

Purpose:

     DLA_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 DOUBLE PRECISION 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 DOUBLE PRECISION array, dimension (LDAFB,N)
         Details of the LU factorization of the band matrix A, 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.

    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'.

Date:
    November 2011

Definition at line 117 of file dla_gbrpvgrw.f'.

Author

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