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 (character NORM, integer N, 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:

December 2016

Definition at line 108 of file clangt.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

The man page clangt(3) is an alias of clangt.f(3).

Tue Nov 14 2017 Version 3.8.0 LAPACK