dlantb man page on Scientific

```DLANTB(1)	    LAPACK auxiliary routine (version 3.2)	     DLANTB(1)

NAME
DLANTB  -  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 triangular band matrix A, with ( k + 1 ) diagonals

SYNOPSIS
DOUBLE PRECISION FUNCTION  DLANTB(  NORM,  UPLO,	 DIAG, N, K, AB, LDAB,
WORK )

CHARACTER	DIAG, NORM, UPLO

INTEGER	K, LDAB, N

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

PURPOSE
DLANTB  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 triangular band matrix A,  with ( k + 1 ) diagonals.

DESCRIPTION
DLANTB returns the value
DLANTB = ( 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 DLANTB as described
above.

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

DIAG    (input) CHARACTER*1
Specifies  whether  or  not the matrix A is unit triangular.  =
'N':  Non-unit triangular
= 'U':  Unit triangular

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

K       (input) INTEGER
The number of super-diagonals of the matrix A if UPLO = 'U', or
the number of sub-diagonals of the matrix A if UPLO =  'L'.   K
>= 0.

AB      (input) DOUBLE PRECISION array, dimension (LDAB,N)
The  upper  or  lower  triangular  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).	Note that when DIAG = 'U', the
elements of the array AB corresponding to the diagonal elements
of the matrix A are not referenced, but are assumed to be one.

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

WORK    (workspace) DOUBLE PRECISION array, dimension (MAX(1,LWORK)),
where LWORK >= N when NORM = 'I'; otherwise, WORK is not refer‐
enced.

LAPACK auxiliary routine (versioNovember 2008			     DLANTB(1)
```
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