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

NAME
       SRC/stbcon.f

SYNOPSIS
   Functions/Subroutines
       subroutine stbcon (norm, uplo, diag, n, kd, ab, ldab, rcond, work,
           iwork, info)
           STBCON

Function/Subroutine Documentation
   subroutine stbcon (character norm, character uplo, character diag, integer
       n, integer kd, real, dimension( ldab, * ) ab, integer ldab, real rcond,
       real, dimension( * ) work, integer, dimension( * ) iwork, integer info)
       STBCON

       Purpose:


            STBCON estimates the reciprocal of the condition number of a
            triangular band matrix A, in either the 1-norm or the infinity-norm.

            The norm of A is computed and an estimate is obtained for
            norm(inv(A)), then the reciprocal of the condition number is
            computed as
               RCOND = 1 / ( norm(A) * norm(inv(A)) ).

       Parameters
           NORM

                     NORM is CHARACTER*1
                     Specifies whether the 1-norm condition number or the
                     infinity-norm condition number is required:
                     = '1' or 'O':  1-norm;
                     = 'I':         Infinity-norm.

           UPLO

                     UPLO is CHARACTER*1
                     = 'U':  A is upper triangular;
                     = 'L':  A is lower triangular.

           DIAG

                     DIAG is CHARACTER*1
                     = 'N':  A is non-unit triangular;
                     = 'U':  A is unit triangular.

           N

                     N is INTEGER
                     The order of the matrix A.  N >= 0.

           KD

                     KD is INTEGER
                     The number of superdiagonals or subdiagonals of the
                     triangular band matrix A.  KD >= 0.

           AB

                     AB is REAL array, dimension (LDAB,N)
                     The upper or lower triangular band matrix A, stored in the
                     first kd+1 rows of the array. The j-th column of A is stored
                     in the j-th column of the array AB as follows:
                     if UPLO = 'U', AB(kd+1+i-j,j) = A(i,j) for max(1,j-kd)<=i<=j;
                     if UPLO = 'L', AB(1+i-j,j)    = A(i,j) for j<=i<=min(n,j+kd).
                     If DIAG = 'U', the diagonal elements of A are not referenced
                     and are assumed to be 1.

           LDAB

                     LDAB is INTEGER
                     The leading dimension of the array AB.  LDAB >= KD+1.

           RCOND

                     RCOND is REAL
                     The reciprocal of the condition number of the matrix A,
                     computed as RCOND = 1/(norm(A) * norm(inv(A))).

           WORK

                     WORK is REAL array, dimension (3*N)

           IWORK

                     IWORK is INTEGER array, dimension (N)

           INFO

                     INFO is INTEGER
                     = 0:  successful exit
                     < 0:  if INFO = -i, the i-th argument had an illegal value

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Definition at line 141 of file stbcon.f.

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

LAPACK                          Version 3.12.0                 SRC/stbcon.f(3)