#!/usr/bin/perl -wuse strict;my $stem = $ARGV[0];if (!defined $stem) {  print STDERR "usage: multi-bleu.pl reference.filestem < hypothesis\n";  print STDERR "Reads the references from reference.filestem.0, reference.filestem.1, ...\n";  exit(1);}my @REF;my $ref=0;while(-e "$stem$ref") {    &add_to_ref("$stem$ref",\@REF);    $ref++;}&add_to_ref($stem,\@REF) if -e $stem;sub add_to_ref {    my ($file,$REF) = @_;    my $s=0;    open(REF,$file) or die "Can't read $file";    while(<REF>) {	chop;	push @{$$REF[$s++]}, $_;    }    close(REF);}my(@CORRECT,@TOTAL,$length_translation,$length_reference);my $s=0;while(<STDIN>) {    chop;    my @WORD = split;    my %REF_NGRAM = ();    my $length_translation_this_sentence = scalar(@WORD);    my ($closest_diff,$closest_length) = (9999,9999);    foreach my $reference (@{$REF[$s]}) {#      print "$s $_ <=> $reference\n";	my @WORD = split(/ /,$reference);	my $length = scalar(@WORD);        my $diff = abs($length_translation_this_sentence-$length);	if ($diff < $closest_diff) {	    $closest_diff = $diff;	    $closest_length = $length;	    # print STDERR "$s: closest diff ".abs($length_translation_this_sentence-$length)." = abs($length_translation_this_sentence-$length), setting len: $closest_length\n";	} elsif ($diff == $closest_diff) {            $closest_length = $length if $length < $closest_length;            # from two references with the same closeness to me            # take the *shorter* into account, not the "first" one.        }	for(my $n=1;$n<=4;$n++) {	    my %REF_NGRAM_N = ();	    for(my $start=0;$start<=$#WORD-($n-1);$start++) {		my $ngram = "$n";		for(my $w=0;$w<$n;$w++) {		    $ngram .= " ".$WORD[$start+$w];		}		$REF_NGRAM_N{$ngram}++;	    }	    foreach my $ngram (keys %REF_NGRAM_N) {		if (!defined($REF_NGRAM{$ngram}) || 		    $REF_NGRAM{$ngram} < $REF_NGRAM_N{$ngram}) {		    $REF_NGRAM{$ngram} = $REF_NGRAM_N{$ngram};#	    print "$i: REF_NGRAM{$ngram} = $REF_NGRAM{$ngram}<BR>\n";		}	    }	}    }    $length_translation += $length_translation_this_sentence;    $length_reference += $closest_length;    for(my $n=1;$n<=4;$n++) {	my %T_NGRAM = ();	for(my $start=0;$start<=$#WORD-($n-1);$start++) {	    my $ngram = "$n";	    for(my $w=0;$w<$n;$w++) {		$ngram .= " ".$WORD[$start+$w];	    }	    $T_NGRAM{$ngram}++;	}	foreach my $ngram (keys %T_NGRAM) {	    $ngram =~ /^(\d+) /;	    my $n = $1;            # my $corr = 0;#	print "$i e $ngram $T_NGRAM{$ngram}<BR>\n";	    $TOTAL[$n] += $T_NGRAM{$ngram};	    if (defined($REF_NGRAM{$ngram})) {		if ($REF_NGRAM{$ngram} >= $T_NGRAM{$ngram}) {		    $CORRECT[$n] += $T_NGRAM{$ngram};                    # $corr =  $T_NGRAM{$ngram};#	    print "$i e correct1 $T_NGRAM{$ngram}<BR>\n";		}		else {		    $CORRECT[$n] += $REF_NGRAM{$ngram};                    # $corr =  $REF_NGRAM{$ngram};#	    print "$i e correct2 $REF_NGRAM{$ngram}<BR>\n";		}	    }            # $REF_NGRAM{$ngram} = 0 if !defined $REF_NGRAM{$ngram};            # print STDERR "$ngram: {$s, $REF_NGRAM{$ngram}, $T_NGRAM{$ngram}, $corr}\n"	}    }    $s++;}my $brevity_penalty = 1;my $bleu = 0;my @bleu=();for(my $n=1;$n<=4;$n++) {  if (defined ($TOTAL[$n])){    $bleu[$n]=($TOTAL[$n])?$CORRECT[$n]/$TOTAL[$n]:0;    # print STDERR "CORRECT[$n]:$CORRECT[$n] TOTAL[$n]:$TOTAL[$n]\n";  }else{    $bleu[$n]=0;  }}if ($length_reference==0){  printf "BLEU = 0, 0/0/0/0 (BP=0, ration=0, hyp_len=0, ref_len=0)\n";  exit(1);}if ($length_translation<$length_reference) {  $brevity_penalty = exp(1-$length_reference/$length_translation);}$bleu = $brevity_penalty * exp((my_log( $bleu[1] ) +				my_log( $bleu[2] ) +				my_log( $bleu[3] ) +				my_log( $bleu[4] ) ) / 4) ;printf "BLEU = %.2f, %.1f/%.1f/%.1f/%.1f (BP=%.3f, ration=%.3f, hyp_len=%d, ref_len=%d)\n",    100*$bleu,    100*$bleu[1],    100*$bleu[2],    100*$bleu[3],    100*$bleu[4],    $brevity_penalty,    $length_translation / $length_reference,    $length_translation,    $length_reference;sub my_log {  return -9999999999 unless $_[0];  return log($_[0]);}