clangt.f man page

clangt.f —

Synopsis

Functions/Subroutines

REAL function clangt (NORM, N, DL, D, DU)
CLANGT returns the value of the 1-norm, Frobenius norm, infinity-norm, or the largest absolute value of any element of a general tridiagonal matrix.

Function/Subroutine Documentation

REAL function clangt (characterNORM, integerN, complex, dimension( * )DL, complex, dimension( * )D, complex, dimension( * )DU)

CLANGT returns the value of the 1-norm, Frobenius norm, infinity-norm, or the largest absolute value of any element of a general tridiagonal matrix.

Purpose:

CLANGT  returns the value of the one norm,  or the Frobenius norm, or
the  infinity norm,  or the  element of  largest absolute value  of a
complex tridiagonal matrix A.

Returns:

CLANGT

   CLANGT = ( 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.

Parameters:

NORM

NORM is CHARACTER*1
Specifies the value to be returned in CLANGT as described
above.

N

N is INTEGER
The order of the matrix A.  N >= 0.  When N = 0, CLANGT is
set to zero.

DL

DL is COMPLEX array, dimension (N-1)
The (n-1) sub-diagonal elements of A.

D

D is COMPLEX array, dimension (N)
The diagonal elements of A.

DU

DU is COMPLEX array, dimension (N-1)
The (n-1) super-diagonal elements of A.

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

September 2012

Definition at line 107 of file clangt.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

clangt(3) is an alias of clangt.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK