mktrajectory

#! /usr/bin/perl

# vasptrajectory
# Extracts the atoms positions from a VASP OUTCAR

open OUTCAR, "OUTCAR" or die "OUTCAR not found:";
open CONTCAR, "CONTCAR" or die "CONTCAR not found:";

my @outcar = <OUTCAR>;
my @contcar = <CONTCAR>;

@names = split /\s+/,@contcar[5];
@numbers = split /\s+/,@contcar[6];
@atoms = ();

while (@numbers) {
   $this_number = shift(@numbers);
   $this_label = shift(@names);
   for ( $i=0; $i < $this_number; $i++ ) {
       # print "$this_label\n";
       push (@atoms, $this_label);
   }
}

$nframes = 0;

while (@outcar) {
   my @thisline = split /\s+/,shift(@outcar);
   if ($thisline[1] =~ /POSITION/){
       shift(@outcar);
       @thisline = split /\s+/,shift(@outcar);
       $frame_out = "";
       $natoms = 0;
       until ($thisline[1] =~ m/--/) {
           $frame_out = "$frame_out$atoms[$natoms]  $thisline[1]  $thisline[2]  $thisline[3]\n";
           @thisline = split /\s+/,shift(@outcar);
           $natoms++;
       }
       print "$natoms\n";
       print "$nframes\n";
       print "$frame_out";
       $nframes++;
   }
}