Lttoolbox

lttoolbox is a toolbox for lexical processing, morphological analysis and generation of words. Analysis is the process of splitting a word (e.g. cats) into its lemma 'cat' and the grammatical information <n><pl>. Generation is the opposite process.

The package is split into three programs, lt-comp, the compiler, lt-proc, the processor, and lt-expand, which generates all possible mappings between surface forms and lexical forms in the dictionary.

Creation

Main article: Monodix basics

Morphological analyser specification files, or morphological dictionaries may be found in all of our language pair packages, from the incubator, or you may elect to create your own (more instructions at the page Monodix basics). You can also check out our list of dictionaries, which has statistics on names, locations and number of entries of each of the dictionaries.

Usage

Compilation

See also: Compiling dictionaries

Compilation into the binary format is achieved by means of the lt-comp program. You can compile a given .dix from left to right (LR), or from right to left (RL). Compiling LR usually creates an analyser, compiling RL usually creates a generator.

Example

Compile the apertium-es-ca.ca.dix dictionary in a left-to-right manner into the binary ca.bin.

$ lt-comp lr apertium-es-ca.ca.dix ca.bin

Processing

There are two main modes of use for the processor (lt-proc), analysis (which is the default mode) and generation. Analysis converts surface forms into the set of possible lexical forms, while generation converts a lexical form into the corresponding surface form.

Analysis

After compiling the apertium-es-ca.ca.dix file left-to-right into ca.morf.bin, we can analyse Catalan:

Example

$ echo "prova" | lt-proc ca.morf.bin

^prova/prova<n><f><sg>/provar<vblex><pri><p3><sg>/provar<vblex><imp><p2><sg>$

Generation

And compiling it right-to-left, we can generate:

Example

$ echo "^prova<n><f><pl>$"  | lt-proc -g ca.gen.bin

proves

Expansion

Sometimes you want to be able to see the complete output of the dictionary — i.e., all of the mappings between lexical and surface forms. For this you can use the lt-expand tool. This output is often useful in finding bugs in the assignment of paradigms, etc.

Example

Here are the first ten lines that are produced as output from the command to expand the Catalan dictionary in the apertium-es-ca pair. (At last count, the total length of the output was over 2.3 million lines.)

$ lt-expand apertium-es-ca.ca.dix 

abdominals:abdominal<adj><mf><pl>
abdominal:abdominal<adj><mf><sg>
absents:absent<adj><mf><pl>
absent:absent<adj><mf><sg>
absolutes:absolut<adj><f><pl>
absoluta:absolut<adj><f><sg>
absoluts:absolut<adj><m><pl>
absolut:absolut<adj><m><sg>
abstractes:abstracte<adj><mf><pl>
abstracta:abstracte<adj><f><sg>

Printing

<dictionary>
  <alphabet>abcdefghijklmnopqrstuvwxyz</alphabet>
  <sdefs>
    <sdef n="n"/>
    <sdef n="sg"/>
    <sdef n="pl"/>
  </sdefs>

  <section id="main" type="standard">
    <e><p><l>beer</l><r>beer<s n="n"/><s n="sg"/></r></p></e>
    <e><p><l>beers</l><r>beer<s n="n"/><s n="pl"/></r></p></e>
  </section>
</dictionary>

$ lt-comp lr /tmp/test.dix /tmp/test.bin
main@standard 8 8

$ lt-print /tmp/test.bin 
0	1	b	b	
1	2	e	e	
2	3	e	e	
3	4	r	r	
4	5	ε	<n>	
4	6	s	<n>	
5	7	ε	<sg>	
6	7	ε	<pl>	
7

Troubleshooting

Empty left side

If you get a message like:

Error: Invalid dictionary (hint: the left side of an entry is empty)

Try searching for empty left sides in your dictionary by using lt-expand and grep. For example, in the Icelandic dictionary,

$ lt-expand apertium-fo-is.is.dix  | grep ^:
:kunna<vblex><imp><p2><sg>
:kunna<vblex><imp><p1><pl>
:kunna<vblex><imp><p2><pl>

The empty left side will look something like:

      <e>
        <p>
          <l></l>
          <r>kunna<s n="vblex"/><s n="imp"/><s n="p2"/><s n="pl"/></r>
        </p>
      </e>

It is not possible to have an empty left side in a paradigm if you have no invariant (<i>) section in the main section entry, e.g.

    <e lm="kunna"><i></i><par n="/kunna__vblex"/></e>

This means you should look for the "kunna" verb; where the left side is empty, you should either put something there or add something to the invariant section.

Speed

$ yes word | head -10000000 > /tmp/foo

$ head /tmp/foo
word
word
word
...

$ wc -l /tmp/foo
1000000 /tmp/foo

$ time cat /tmp/foo | lt-proc en-ca.automorf.bin >/dev/null

real	0m17.606s
user	0m17.281s
sys	0m0.036s

58,823 words / second

Using as a library

See Lttoolbox API for how to analyse and generate words with lttoolbox from C++ or Python.

Wishlist

• Being able to have multichar symbols/tags without '<' and '>'

See also

• Monodix basics
• Using an lttoolbox dictionary
• lttoolbox and lexc
• Lttoolbox-java
• Basic lttoolbox example