Difference between revisions of "Lttoolbox-java"

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sudo make install
sudo make install
You can also build and install using Maven 2 (http://maven.apache.org), by typing:
mvn install

Revision as of 03:45, 20 February 2010

What is lttoolbox

lttoolbox are 1) making binary files out of the .dix files (lt-comp), 2) analysing or generating text (lt-proc) and 3) expanding a .dix file (lt-expand).


  • Binary compatibility with lttoolbox. lttoolbox-java is able _read_ and _write_ the binary files lttoolbox and generates exactly the same output
  • There is a comprehensive test suite that tests both lttoolbox (C++) and lttoolbox-java.


Use Netbeans or Unix, whatever suits you best:

sh autogen.sh
sudo make install

You can also build and install using Maven 2 (http://maven.apache.org), by typing:

mvn install

See also the README file


$ java -jar dist/lttoolbox.jar
lttoolbox: is a toolbox for lexical processing, morphological analysis and generation of words
USAGE: java -jar dist/lttoolbox.jar [task]
 java -jar dist/lttoolbox.jar lt-expand dictionary.dix     expands a dictionary
 java -jar dist/lttoolbox.jar lt-comp lr dic.dix dic.bin   compiles a dictionary
 java -jar dist/lttoolbox.jar lt-proc dic.bin              morphological analysis

or, using the a shell scripts:

$ lt-comp-j 
 v3.2j: build a letter transducer from a dictionary
USAGE: LTComp lr | rl dictionary_file output_file [acx_file]
  lr:     left-to-right compilation
  rl:     right-to-left compilation

$ lt-proc-j
LTProc: process a stream with a letter transducer
USAGE: LTProc [-c] [-a|-g|-n|-d|-b|-p|-s|-t] fst_file [input_file [output_file]]
  -a:   morphological analysis (default behavior)
  -c:   use the literal case of the incoming characters
  -e:   morphological analysis, with compound analysis on unknown words
  -f:   match flags (experimental)
  -g:   morphological generation
  -n:   morph. generation without unknown word marks
  -d:   morph. generation with all the stuff
  -t:   morph. generation, but retaining part-of-speech
  -p:   post-generation
  -s:   SAO annotation system input processing
  -t:   apply transliteration dictionary
  -z:   flush output on the null character 
  -v:   version
  -D:   debug; print diagnostics to stderr
  -h:   show this help

$ lt-expand-j 
 v3.2j: expand the contents of a dictionary fileUSAGE: LTExpand dictionary_file [output_file]

$ lt-validate-j 
 v3.2j: validate an XML file according to a schema
USAGE : LTValidate -dix dictionary.xml
        LTValidate -acx dictionary.acx


Use the new compounding feature:

echo "lambakjöti" | java -jar dist/lttoolbox.jar lt-proc -e /home/j/esperanto/apertium/apertium-is-en/is.bin


Encoding problems

Try -Dfile.encoding=UTF-8, like

echo "lambakjöti" | java -Dfile.encoding=UTF-8 -jar dist/lttoolbox.jar lt-proc -e /home/j/esperanto/apertium/apertium-is-en/is.bin


Mac users

You need JDK1.6. Try

/System/Library/Frameworks/JavaVM.framework/Versions/1.6/Commands/java -jar dist/lttoolbox.jar

Reasons for a Java port

  • There are several devices (mobile phones, for example) which can run quite complicated software, but only if written in Java. lttoolbox is the first step to having Apertium run on these devices.
  • Windows port. It won't be as powerfull as Unix based system, but it will be there
  • Apertium will be the first MT system *ever* that can be demonstradet within a Java applets
  • Transfer in bytecode has a promise of speedup factor 4 - compared to what we use now (interpreted XML). And transfer CPU usage is dominating when processing large amounts of text

State of Java port

Compatibility and performance can be checked by invoking test_java_and_c.sh in testdata/regression.

C analysis is... 0.39sec
Java analysis is... 1.85sec
C generator -g is ... 0.32sec
Java generator -g is ... 2.01sec
C generator -d is ... 0.85sec
Java generator -d is ... 2.14sec
C generator -n is ... 0.92sec
Java generator -n is ... 1.77sec
C postgenerator -p is ... 0.04sec
Java postgenerator -p is ... 0.81sec
All tests passed

As you see Java version is currently (jan 2010) a factor 2-8 slower than the C version. There are ways to remedy this (i.a. using simple types collection classes), but it hasnt been implemented, as no-one has requested it.

It still gives great performance, however, and Apertium running on Java is very fast, compared to other MT systems. The overhead of using the Java version instead of the C version is negligible, as transfer is the big ressource hog anyway.

Known bugs

There are currently (jan 2010) problems compiling some very seldom strange constructs (testdata/strange.dix). You can use the C version to compile these, and the binary files will work fine when used from lttoolbox-java.

Other notes

<Drew_> jacobEo: I can't find a main class in the source code, am I looking in the wrong place? :S
<jacobEo> Drew_: LTComp.java, LTExpand.java, LTProc.java


  • Nic Cottrell contributed an initial version of a Java port of lttoolbox.
  • During GSOC2009 Raphaël and Sergio worked on it, but processing still didnt work (compilation and expansion worked)
  • November 2009 Jacob Nordfalk finished it up and optimized it