MaltBlender is an tool for merging the output of several dependency parsers, using the Chu-Liu/Edmonds directed MST algorithm (Sagae and Lavie 2006). This software was used by the wining team of the CoNLL-XI Shared Task (Hall et al. 2007).
MaltBlender requires Java JRE 1.5 or later, Perl v5.8.1 or later, and the evaluation script eval07.pl from CoNLL-XI Shared Task 2007.
Run MaltBlender: java -DPERL=<perl_path> -DEVALUATOR=<eval07.pl_path> -jar MaltBlender.jar -w 4 -o out.conll -l 4 -h <held-out_gold_file> -H <held-out_parsed_files> -F <parsed file>
-DPREL = path to perl
-DEVALUATOR = path to eval07.pl
-h = the gold-standard file for the held-out data, which is used for estimating the weights together with the parsed files after -H
-H = the parsed file for the held-out data; separate the files wth a white space
-F = parsed file to be combined (make sure that the number of files after -H and -F is the same. Note that the ith file after -H is used for estimating the weight of the ith file after -F)
Note that the two first arguments, -DPREL and -DEVALUATOR, have to be located before "-jar", since they are arguments to the java interpreter, not MaltBlender.