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

NAME
       SRC/dla_gbrcond.f

SYNOPSIS
   Functions/Subroutines
       double precision function dla_gbrcond (trans, n, kl, ku, ab, ldab, afb,
           ldafb, ipiv, cmode, c, info, work, iwork)
           DLA_GBRCOND estimates the Skeel condition number for a general
           banded matrix.

Function/Subroutine Documentation
   double precision function dla_gbrcond (character trans, integer n, integer
       kl, integer ku, double precision, dimension( ldab, * ) ab, integer
       ldab, double precision, dimension( ldafb, * ) afb, integer ldafb,
       integer, dimension( * ) ipiv, integer cmode, double precision,
       dimension( * ) c, integer info, double precision, dimension( * ) work,
       integer, dimension( * ) iwork)
       DLA_GBRCOND estimates the Skeel condition number for a general banded
       matrix.

       Purpose:


           !>
           !>    DLA_GBRCOND Estimates the Skeel condition number of  op(A) * op2(C)
           !>    where op2 is determined by CMODE as follows
           !>    CMODE =  1    op2(C) = C
           !>    CMODE =  0    op2(C) = I
           !>    CMODE = -1    op2(C) = inv(C)
           !>    The Skeel condition number  cond(A) = norminf( |inv(A)||A| )
           !>    is computed by computing scaling factors R such that
           !>    diag(R)*A*op2(C) is row equilibrated and computing the standard
           !>    infinity-norm condition number.
           !>

       Parameters
           TRANS

           !>          TRANS is CHARACTER*1
           !>     Specifies the form of the system of equations:
           !>       = 'N':  A * X = B     (No transpose)
           !>       = 'T':  A**T * X = B  (Transpose)
           !>       = 'C':  A**H * X = B  (Conjugate Transpose = Transpose)
           !>

           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.
           !>

           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.
           !>

           IPIV

           !>          IPIV is INTEGER array, dimension (N)
           !>     The pivot indices from the factorization A = P*L*U
           !>     as computed by DGBTRF; row i of the matrix was interchanged
           !>     with row IPIV(i).
           !>

           CMODE

           !>          CMODE is INTEGER
           !>     Determines op2(C) in the formula op(A) * op2(C) as follows:
           !>     CMODE =  1    op2(C) = C
           !>     CMODE =  0    op2(C) = I
           !>     CMODE = -1    op2(C) = inv(C)
           !>

           C

           !>          C is DOUBLE PRECISION array, dimension (N)
           !>     The vector C in the formula op(A) * op2(C).
           !>

           INFO

           !>          INFO is INTEGER
           !>       = 0:  Successful exit.
           !>     i > 0:  The ith argument is invalid.
           !>

           WORK

           !>          WORK is DOUBLE PRECISION array, dimension (5*N).
           !>     Workspace.
           !>

           IWORK

           !>          IWORK is INTEGER array, dimension (N).
           !>     Workspace.
           !>

       Author
           Univ. of Tennessee


           Univ. of California Berkeley


           Univ. of Colorado Denver


           NAG Ltd.

       Definition at line 167 of file dla_gbrcond.f.

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

LAPACK                          Version 3.12.0            SRC/dla_gbrcond.f(3)