dlanst.f man page

dlanst.f —

Synopsis

Functions/Subroutines

DOUBLE PRECISION function dlanst (NORM, N, D, E)
DLANST returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a real symmetric tridiagonal matrix.

Function/Subroutine Documentation

DOUBLE PRECISION function dlanst (characterNORM, integerN, double precision, dimension( * )D, double precision, dimension( * )E)

DLANST returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a real symmetric tridiagonal matrix.

Purpose:

DLANST  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 symmetric tridiagonal matrix A.

Returns:

DLANST

   DLANST = ( 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 DLANST as described
above.

N

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

D

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

E

E is DOUBLE PRECISION array, dimension (N-1)
The (n-1) sub-diagonal or 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 101 of file dlanst.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

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

Sat Nov 16 2013 Version 3.4.2 LAPACK