text: #!/usr/bin/env python
  
  from builtins import range
  from forcebalance.molecule import Molecule
  import os, sys
  
  # Load in the Gromacs .gro file to be converted to TINKER format.
  M = Molecule(sys.argv[1])
  
  # Build the line suffix for the TINKER format.
  tinkersuf = []
  for i in range(M.na):
      if i%3==0:
          tinkersuf.append("%5i %5i %5i" % (1, i+2, i+3))
      else:
          tinkersuf.append("%5i %5i" % (2, i-i%3+1))
  M.tinkersuf = tinkersuf
  
  # Delete the periodic box.
  del M.Data['boxes']
  
  # Write the TINKER output format.
  M.write(os.path.splitext(sys.argv[1])[0]+'.xyz', ftype='tinker')
  