#!/usr/bin/perl -w

use System;

my $a=sqrt(3);
my $c=(5.21/3.21)*$a;
my $m=4.0359394e-26;

$cell=[
  $a*sqrt(3)/2,-$a/2,0,
  0,$a,0,
  0,0,$c,
];

my $atoms=[
  [ "A", $m ],
  [ "B", $m ],
];

my $sites=[
  [ 0,0,0,             0 ],
  [ $a/sqrt(3),0,$c/2, 1 ],
];

my $bonds=[
  [ 0,1, System::axial([ $a/sqrt(3),0, $c/2],           10.483,-0.309) ],
  [ 1,0, System::axial([-$a/sqrt(3),0,-$c/2],           10.483,-0.309) ],

  [ 0,0, System::axial([ 0, $a,0],                      10.099,-0.292) ],
  [ 1,1, System::axial([ 0, $a,0],                      10.099,-0.292) ],

  [ 0,1, System::axial([-2*$a/sqrt(3),0, $c/2],         -0.222,-0.246) ],
  [ 1,0, System::axial([ 2*$a/sqrt(3),0,-$c/2],         -0.222,-0.246) ],

  [ 0,0, System::axial([ 0,0,$c],                        0.305,-0.490) ],
  [ 1,1, System::axial([ 0,0,$c],                        0.305,-0.490) ],

  [ 0,1, System::axial([ 5*$a/(2*sqrt(3)), $a/2, $c/2],  0.748, 0.013) ],
  [ 1,0, System::axial([-5*$a/(2*sqrt(3)),-$a/2,-$c/2],  0.748, 0.013) ],

  [ 0,0, System::axial([ $a*sqrt(3),0,0],                0.529, 0.091) ],
  [ 1,1, System::axial([ $a*sqrt(3),0,0],                0.529, 0.091) ],
  [ 0,0, System::axial([-$a*sqrt(3),0,0],                0.529, 0.091) ],
  [ 1,1, System::axial([-$a*sqrt(3),0,0],                0.529, 0.091) ],

  [ 0,0, System::axial([0,$a,$c],                       -0.049, 0.157) ],
  [ 1,1, System::axial([0,$a,$c],                       -0.049, 0.157) ],

  [ 0,0, System::axial([0,2*$a,0],                      -0.401, 0.042) ],
  [ 1,1, System::axial([0,2*$a,0],                      -0.401, 0.042) ],
];

System::write($cell,$atoms,$sites,$bonds,"hcp");
