moses' multi-bleu.perl

multi-bleu.perl

@@ -0,0 +1,174 @@
+#!/usr/bin/env perl
+#
+# This file is part of moses.  Its use is licensed under the GNU Lesser General
+# Public License version 2.1 or, at your option, any later version.
+
+# $Id$
+use warnings;
+use strict;
+
+my $lowercase = 0;
+if ($ARGV[0] eq "-lc") {
+  $lowercase = 1;
+  shift;
+}
+
+my $stem = $ARGV[0];
+if (!defined $stem) {
+  print STDERR "usage: multi-bleu.pl [-lc] reference < hypothesis\n";
+  print STDERR "Reads the references from reference or reference0, reference1, ...\n";
+  exit(1);
+}
+
+$stem .= ".ref" if !-e $stem && !-e $stem."0" && -e $stem.".ref0";
+
+my @REF;
+my $ref=0;
+while(-e "$stem$ref") {
+    &add_to_ref("$stem$ref",\@REF);
+    $ref++;
+}
+&add_to_ref($stem,\@REF) if -e $stem;
+die("ERROR: could not find reference file $stem") unless scalar @REF;
+
+# add additional references explicitly specified on the command line
+shift;
+foreach my $stem (@ARGV) {
+    &add_to_ref($stem,\@REF) if -e $stem;
+}
+
+
+
+sub add_to_ref {
+    my ($file,$REF) = @_;
+    my $s=0;
+    if ($file =~ /.gz$/) {
+	open(REF,"gzip -dc $file|") or die "Can't read $file";
+    } else { 
+	open(REF,$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;
+    $_ = lc if $lowercase;
+    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";
+  $reference = lc($reference) if $lowercase;
+	my @WORD = split(' ',$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 ($length_reference==0){
+  printf "BLEU = 0, 0/0/0/0 (BP=0, ratio=0, hyp_len=0, ref_len=0)\n";
+  exit(1);
+}
+
+if ($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( $bleu[4] ) ) / 4) ;
+printf "BLEU = %.2f, %.1f/%.1f/%.1f/%.1f (BP=%.3f, ratio=%.3f, hyp_len=%d, ref_len=%d)\n",
+    100*$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]);
+}