clanht.f File Reference

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Functions/Subroutines
REAL function	clanht (NORM, N, D, E)
	CLANHT returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a complex Hermitian tridiagonal matrix.

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Function/Subroutine Documentation

REAL function clanht	(	character	NORM,
		integer	N,
		real, dimension( * )	D,
		complex, dimension( * )	E
	)

CLANHT returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a complex Hermitian tridiagonal matrix.

Download CLANHT + dependencies [TGZ] [ZIP] [TXT]

Purpose:

 CLANHT  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 Hermitian tridiagonal matrix A.

Returns:

CLANHT

    CLANHT = ( 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:

[in]	NORM	NORM is CHARACTER*1 Specifies the value to be returned in CLANHT as described above.
[in]	N	N is INTEGER The order of the matrix A. N >= 0. When N = 0, CLANHT is set to zero.
[in]	D	D is REAL array, dimension (N) The diagonal elements of A.
[in]	E	E is COMPLEX 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 102 of file clanht.f.

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