redhat man page for dlangb

DLANGB(l)								 )								 DLANGB(l)

NAME
       DLANGB - return 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 band matrix A, with kl sub-diagonals and ku super-diagonals

SYNOPSIS
       DOUBLE PRECISION FUNCTION DLANGB( NORM, N, KL, KU, AB, LDAB, WORK )

	   CHARACTER	NORM

	   INTEGER	KL, KU, LDAB, N

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

PURPOSE
       DLANGB 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 band matrix A, with kl sub-diagonals and ku super-diagonals.

DESCRIPTION
       DLANGB returns the value

	  DLANGB = ( 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  Frobenius 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 DLANGB as described above.

       N       (input) INTEGER
	       The order of the matrix A.  N >= 0.  When N = 0, DLANGB is set to zero.

       KL      (input) INTEGER
	       The number of sub-diagonals of the matrix A.  KL >= 0.

       KU      (input) INTEGER
	       The number of super-diagonals of the matrix A.  KU >= 0.

       AB      (input) DOUBLE PRECISION array, dimension (LDAB,N)
	       The band matrix A, stored 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    (input) INTEGER
	       The leading dimension of the array AB.  LDAB >= KL+KU+1.

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

LAPACK version 3.0						   15 June 2000 							 DLANGB(l)