dlangt(l) [redhat man page]

DLANGT(l)								 )								 DLANGT(l)

NAME

       DLANGT  - return the value of the one norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a real
       tridiagonal matrix A

SYNOPSIS

       DOUBLE PRECISION FUNCTION DLANGT( NORM, N, DL, D, DU )

	   CHARACTER	NORM

	   INTEGER	N

	   DOUBLE	PRECISION D( * ), DL( * ), DU( * )

PURPOSE

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

DESCRIPTION

       DLANGT returns the value

	  DLANGT = ( 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 DLANGT as described above.

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

       DL      (input) DOUBLE PRECISION array, dimension (N-1)
	       The (n-1) sub-diagonal elements of A.

       D       (input) DOUBLE PRECISION array, dimension (N)
	       The diagonal elements of A.

       DU      (input) DOUBLE PRECISION array, dimension (N-1)
	       The (n-1) super-diagonal elements of A.

LAPACK version 3.0						   15 June 2000 							 DLANGT(l)

dlangt.f(3)							      LAPACK							       dlangt.f(3)

NAME

       dlangt.f -

SYNOPSIS

   Functions/Subroutines
       DOUBLE PRECISION function dlangt (NORM, N, DL, D, DU)
	   DLANGT 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
   DOUBLE PRECISION function dlangt (characterNORM, integerN, double precision, dimension( * )DL, double precision, dimension( * )D, double
       precision, dimension( * )DU)
       DLANGT 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:

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

       Returns:
	   DLANGT

	       DLANGT = ( 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 DLANGT as described
		     above.

	   N

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

	   DL

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

	   D

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

	   DU

		     DU is DOUBLE PRECISION 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 dlangt.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.2							  Tue Sep 25 2012						       dlangt.f(3)