DLANSB  -  return the value of the one norm, or the Frobe­
       nius norm, or the infinity norm, or the element of largest
       absolute  value of an n by n symmetric band matrix A, with
       k super-diagonals


SYNOPSIS

       DOUBLE PRECISION FUNCTION DLANSB( NORM, UPLO,  N,  K,  AB,
                        LDAB, WORK )

           CHARACTER    NORM, UPLO

           INTEGER      K, LDAB, N

           DOUBLE       PRECISION AB( LDAB, * ), WORK( * )


PURPOSE

       DLANSB returns the value of the one norm, or the Frobenius
       norm, or the infinity norm,  or  the  element  of  largest
       absolute  value of an n by n symmetric band matrix A, with
       k super-diagonals.


DESCRIPTION

       DLANSB returns the value

          DLANSB = ( max(abs(A(i,j))), NORM = 'M' or 'm'
                   (
                   ( norm1(A),         NORM = '1', 'O' or 'o'
                   (
                   ( normI(A),         NORM = 'I' or 'i'
                   (
                   ( normF(A),         NORM = 'F',  'f',  'E'  or
       'e'

       where   norm1   denotes the  one norm of a matrix (maximum
       column sum), normI   denotes  the   infinity  norm   of  a
       matrix   (maximum  row sum) and normF  denotes the  Frobe­
       nius norm of a matrix (square root  of  sum  of  squares).
       Note that  max(abs(A(i,j)))  is not a  matrix norm.


ARGUMENTS

       NORM    (input) CHARACTER*1
               Specifies  the  value  to be returned in DLANSB as
               described above.

       UPLO    (input) CHARACTER*1
               Specifies whether the upper  or  lower  triangular
               part  of  the  band  matrix A is supplied.  = 'U':
               Upper triangular part is supplied
               = 'L':  Lower triangular part is supplied

       N       (input) INTEGER
               The order of the matrix A.  N >= 0.  When N  =  0,


       K       (input) INTEGER
               The  number of super-diagonals or sub-diagonals of
               the band matrix A.  K >= 0.

       AB      (input) DOUBLE PRECISION array, dimension (LDAB,N)
               The  upper or lower triangle of the symmetric band
               matrix A, stored in the first K+1 rows of AB.  The
               j-th  column  of A is stored in the j-th column of
               the array AB as follows: if UPLO = 'U',  AB(k+1+i-
               j,j) = A(i,j) for max(1,j-k)<=i<=j; if UPLO = 'L',
               AB(1+i-j,j)   = A(i,j) for j<=i<=min(n,j+k).

       LDAB    (input) INTEGER
               The leading dimension of the array  AB.   LDAB  >=
               K+1.

       WORK    (workspace) DOUBLE PRECISION array, dimension
               (LWORK),
               where LWORK >= N when NORM = 'I' or  '1'  or  'O';
               otherwise, WORK is not referenced.


Man(1) output converted with man2html