Chimie Théorique » Opt'n Path

SUBROUTINE  add2indzmat(na,izm,n1,n2,n3,n4,ind_zmat,x,y,z)

  ! This subroutine adds the description of atom n1

  ! into ind_zmat at position izm

  ! it checks that atoms n1 n2 n3 are not aligned

  ! and if so, it describes n1 as n1 n2 n4 n3 instead of n1 n2 n3 n4.

  ! As n2 n3 n4 are not aligned, this is sufficient to ensure that the description

  ! of n1 is ok.

  IMPLICIT NONE

  INTEGER, PARAMETER :: KINT=KIND(1)

  INTEGER, PARAMETER :: KREAL=KIND(1.0D0)

  INTEGER(KINT), INTENT(IN) :: na,izm,n1,n2

  INTEGER(KINT), INTENT(INOUT) :: n3,n4

  INTEGER(KINT) :: ind_zmat(na,5),n0

  REAL(KREAL) :: x(na), y(na), z(na)

  real(KREAL) :: vx1,vy1,vz1,norm1

  real(KREAL) :: vx2,vy2,vz2,norm2

  real(KREAL) :: vx3,vy3,vz3,norm3

  REAL(KREAL) :: pi

  LOGICAL :: debug

  REAL(KREAL) :: Ang123,Ang234,sangle

  INTERFACE

     function valid(string) result (isValid)

       CHARACTER(*), intent(in) :: string

       logical                  :: isValid

     END function VALID

     FUNCTION angle(v1x,v1y,v1z,norm1,v2x,v2y,v2z,norm2)

       use Path_module, only :  Pi,KINT, KREAL

       real(KREAL) ::  v1x,v1y,v1z,norm1

       real(KREAL) ::  v2x,v2y,v2z,norm2

       real(KREAL) ::  angle

     END FUNCTION ANGLE

  END INTERFACE

  debug=valid("add2indzmat")

  pi=acos(-1.d0)

  if (debug) WRITE(*,*) "Entering Add2IndZmat with izm,n1,n2,n3,n4",izm,n1,n2,n3,n4

  Call vecteur(n2,n1,x,y,z,vx1,vy1,vz1,norm1)

  Call vecteur(n2,n3,x,y,z,vx2,vy2,vz2,norm2)

  Call vecteur(n3,n4,x,y,z,vx3,vy3,vz3,norm3)

  Ang123=angle(vx1,vy1,vz1,norm1,vx2,vy2,vz2,norm2)/180.*pi

  Ang234=angle(vx2,vy2,vz2,norm2,vx3,vy3,vz3,norm3)/180.*pi

  sangle=sin(ang123)

  if (sangle.LE.0.09d0) THEN

     sangle=sin(ang234)

     if (sangle.LE.0.09d0) THEN

        WRITE(*,*) "ERROR in Add2IndZmat : all four atoms aligned"

        WRITE(*,*) n1,n2,n3,n4

        STOP

     END IF

     n0=n3

     n3=n4

     n4=n0

  END IF

  ind_zmat(izm,1)=n1

  ind_zmat(izm,2)=n2

  ind_zmat(izm,3)=n3

  ind_zmat(izm,4)=n4

  RETURN

END SUBROUTINE add2indzmat