NAME
    mattrace - trace of a square matrix

SYNOPSIS
    mattrace(m)

TYPES
    m		square matrix with summable diagonal elements

    return	determined by addition of elements

DESCRIPTION
    For a two-dimensional square matrix, mattrace(m) returns the sum of
    the elements on the principal diagonal.  In particular, if m
    has been created by mat m[N,N] where N > 0, mattrace(m) returns

		m[0,0] + m{1,1] + ... + m[N-1,N-1]

EXAMPLE
    ; mat m[2,2] = {1,2,3,4}
    ; print mattrace(m), mattrace(m^2)
    5 29

LIMITS
    none

LINK LIBRARY
    none

SEE ALSO
    mat, mattrans

## Copyright (C) 1999  Landon Curt Noll
##
## Calc is open software; you can redistribute it and/or modify it under
## the terms of the version 2.1 of the GNU Lesser General Public License
## as published by the Free Software Foundation.
##
## Calc is distributed in the hope that it will be useful, but WITHOUT
## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
## or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU Lesser General
## Public License for more details.
##
## A copy of version 2.1 of the GNU Lesser General Public License is
## distributed with calc under the filename COPYING-LGPL.  You should have
## received a copy with calc; if not, write to Free Software Foundation, Inc.
## 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
##
## @(#) $Revision: 30.1 $
## @(#) $Id: mattrace,v 30.1 2007/03/16 11:10:42 chongo Exp $
## @(#) $Source: /usr/local/src/cmd/calc/help/RCS/mattrace,v $
##
## Under source code control:	1997/09/06 20:03:35
## File existed as early as:	1997
##
## chongo <was here> /\oo/\	http://www.isthe.com/chongo/
## Share and enjoy!  :-)	http://www.isthe.com/chongo/tech/comp/calc/