Provided by: liblapack-doc_3.3.1-1_all NAME

LAPACK-3 - 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

SYNOPSIS

REAL FUNCTION CLANGB( NORM, N, KL, KU, AB, LDAB, WORK )

CHARACTER NORM

INTEGER   KL, KU, LDAB, N

REAL      WORK( * )

COMPLEX   AB( LDAB, * )

PURPOSE

CLANGB   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

CLANGB returns the value
CLANGB = ( 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 consistent matrix norm.

ARGUMENTS

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

N       (input) INTEGER
The order of the matrix A.  N >= 0.  When N = 0, CLANGB 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) COMPLEX 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) REAL array, dimension (MAX(1,LWORK)),
where LWORK >= N when NORM = 'I'; otherwise, WORK is not
referenced.

LAPACK auxiliary routine (version 3.2)     April 2011                            CLANGB(3lapack)