calcelem.h

OFELI is an object oriented library of C++ classes for development of finite element codes. Its main

/*==============================================================================

   Copyright (C) 1998 - 2002 Rachid Touzani

   This program is free software; you can redistribute it and/or modify it under
   the terms of the GNU General Public License as published by the Free 
   Software Foundation; Version 2 of the License.

   This program 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 General Public License for more 
   details.

   You should have received a copy of the GNU General Public License 
   along with this program; if not, write to the :

   Free Software Foundation
   Inc., 59 Temple Place - Suite 330
   Boston, MA  02111-1307, USA

  ==============================================================================*/

#ifndef __CALC_ELEM_H
#define __CALC_ELEM_H

#include "Element.h"
#include "Point.h"
#include "LocalVect.h"

using namespace OFELI;

inline double CalcElem(const Element &e, LocalVect<double,3> &dx, 
                                         LocalVect<double,3> &dy)
/*-----------------------------------------------------------------------------
    Calculate derivatives of shape functions and return jacobian of element

    dx[i]/det, dy[i]/det : x and y-derivatives of shape function for node i
  -----------------------------------------------------------------------------*/
{
   Point<> x1 = e.PtrNode(1)->Coord();
   Point<> x2 = e.PtrNode(2)->Coord();
   Point<> x3 = e.PtrNode(3)->Coord();
   dx[0] = x2.y-x3.y; dx[1] = x3.y-x1.y; dx[2] = x1.y-x2.y;
   dy[0] = x3.x-x2.x; dy[1] = x1.x-x3.x; dy[2] = x2.x-x1.x;
   return (dy[2]*dx[1] - dy[1]*dx[2]);
}

#endif