checkfour.f90

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!
!   CARACAL - Ring polymer molecular dynamics and rate constant calculations
!             on black-box generated potential energy surfaces
!
!   Copyright (c) 2023 by Julien Steffen (mail@j-steffen.org)
!                         Stefan Grimme (grimme@thch.uni-bonn.de) (QMDFF code)
!
!   Permission is hereby granted, free of charge, to any person obtaining a
!   copy of this software and associated documentation files (the "Software"),
!   to deal in the Software without restriction, including without limitation
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!   and/or sell copies of the Software, and to permit persons to whom the
!   Software is furnished to do so, subject to the following conditions:
!
!   The above copyright notice and this permission notice shall be included in
!   all copies or substantial portions of the Software.
!
!   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
!   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
!   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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!   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!
!     function checkfour: four different bond partners availiable?
!
!     part of QMDFF
! 
logical function checkfour(i,j,k,l)

checkfour=.false.
if(i.eq.j) return
if(i.eq.k) return
if(i.eq.l) return
if(j.eq.k) return
if(j.eq.l) return
if(k.eq.l) return
checkfour=.true.

return
end function checkfour