! Molecular Orbital PACkage (MOPAC)
! Copyright (C) 2021, Virginia Polytechnic Institute and State University
!
! MOPAC is free software: you can redistribute it and/or modify it under
! the terms of the GNU Lesser General Public License as published by
! the Free Software Foundation, either version 3 of the License, or
! (at your option) any later version.
!
! MOPAC 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.
!
! You should have received a copy of the GNU Lesser General Public License
! along with this program.  If not, see <https://www.gnu.org/licenses/>.

! vector cross product
subroutine cross(in1, in2, out)
   implicit none
   double precision, dimension(3), intent(in) :: in1, in2
   double precision, dimension(3), intent(out) :: out

   out(1) = in1(2)*in2(3) - in1(3)*in2(2)
   out(2) = in1(3)*in2(1) - in1(1)*in2(3)
   out(3) = in1(1)*in2(2) - in1(2)*in2(1)
end subroutine cross
