C by Ed Brothers. June 1998.
C234567890123456789012345678901234567890123345678901234567890123456789012<stop

       Subroutine zmake
       implicit double precision(a-h,o-z)
#include "divcon.dim"
#include "divcon.h"

C

C  Variable declaration.


C  Initialization block
      xyzspc=.false.
      r=0.d0
      angle=0.d0
      dih=0.d0
      K=1
      L=2
      M=3

C      The purpose of this subroutine is to return internal coordinates to
C the output file.  Conversion from cartesian to internal is not automatic,
C although various subprograms do it.  This is why there are so many calls in
C this subroutine.  Note that the routine checks to see if the values already
C present, and, if so simply returns.


C Initialize the z-matrix values if they have not been filled already.

      IF (zmat(1,2).ne.0) goto 100

      DO 5 J=1,natoms
         DO 5 I=1,3
            zmat(i,j)=0.d0
            izmat(i,j)=0
            iopt(i,j)=0
  5   CONTINUE

C Calculate distance from atom 1 to atom J.

      DO 10 J=2,natoms
         DO 20 I=1,3
            r=r+(xyz(i,j)-xyz(i,1))**2
 20      CONTINUE
         zmat(1,j)=sqrt(r)
         izmat(1,j)=K
         iopt(1,j)=1
         r=0.d0
 10   CONTINUE

C Calculate angle j-1-2  This is the angle used in the z-matrix.

      DO 30 J=3,natoms
         call bndang(xyz,L,K,J,angle)
         zmat(2,j)=angle
         izmat(2,j)=L
         iopt(2,j)=1
         angle=0.d0
 30   CONTINUE

C Calculate dihderal 1-2-3-j.

      DO 40 J=4,natoms
         call dihedr(xyz,J,K,L,M,DIH)
         zmat(3,j)=dih
         izmat(3,j)=M
         iopt(3,j)=1
         dih=0.d0
 40   CONTINUE

C-RDC       write(iout,*) ' '
C-RDC       write(iout,*) ' Z-MATRIX:'
C-RDC       write(iout,*) ' '

 100  Return
      END