subroutine char SEGMENTS char GROUP
! set dial 1 init
delete atom sele segm name #* end
image erase
key image sele .not all end
set col 
sele segm name SEGMENTS end = 1
sele segm name SEGMENTS end anal aver  color 64 160 6 range auto
!sele segm name SEGMENTS .a by resi weigh 0.1 1.1 end \
!    anal aver color 64 160 6
exit

set vari RMIN real = RESULT_0
set vari RMAX real = RESULT_1
set vari R1 real = RMAX - RMIN 
set vari R1 real = R1 / 32.0

! show vari GROUP
if ( GROUP .eq. "RESIDUE" ) then
ima sele segm name SEGMENTS .a atom name N CA C  end set bond
ima sele segm name SEGMENTS .a atom name P O3' C3' C4' C5' O5' end set bond
ima sele segm name SEGMENTS .a atom name O* .a resi name H2O end set atom cros
set vari IRES inte resi sele anal aver RMAX - R1  RMAX end
image cent calc sele resi numb IRES end
else
ima sele segm name SEGMENTS end set bond
ima sele segm name SEGMENTS .a .not atom name H* .a \
     .not by bond all end set atom cross
set vari IATOM inte atom sele anal aver RMAX - R1  RMAX end
show vari IATOM
image cent atom IATOM

end_if

! image cent calc sele segm name SEGMENTS .a col 160 end

return