1! 2! CalculiX - A 3-dimensional finite element program 3! Copyright (C) 1998 Guido Dhondt 4! 5! This program is free software; you can redistribute it and/or 6! modify it under the terms of the GNU General Public License as 7! published by the Free Software Foundation(version 2); 8! 9! 10! This program is distributed in the hope that it will be useful, 11! but WITHOUT ANY WARRANTY; without even the implied warranty of 12! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13! GNU General Public License for more details. 14! 15! You should have received a copy of the GNU General Public License 16! along with this program; if not, write to the Free Software 17! Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 18! 19 subroutine calcsurf(n1,n2,n3,cotet,surf) 20! 21! calculates the surface of a tetrahedral face consisting 22! of nodes n1,n2 and n3 23! 24 implicit none 25! 26 integer n1,n2,n3 27! 28 real*8 cotet(3,*),s(3),surf 29! 30 s(1)=(cotet(2,n2)-cotet(2,n1))*(cotet(3,n3)-cotet(3,n1))- 31 & (cotet(3,n2)-cotet(3,n1))*(cotet(2,n3)-cotet(2,n1)) 32 s(2)=(cotet(3,n2)-cotet(3,n1))*(cotet(1,n3)-cotet(1,n1))- 33 & (cotet(1,n2)-cotet(1,n1))*(cotet(3,n3)-cotet(3,n1)) 34 s(3)=(cotet(1,n2)-cotet(1,n1))*(cotet(2,n3)-cotet(2,n1))- 35 & (cotet(2,n2)-cotet(2,n1))*(cotet(1,n3)-cotet(1,n1)) 36 surf=dsqrt(s(1)*s(1)+s(2)*s(2)+s(3)*s(3))/2.d0 37! 38 return 39 end 40