word.alignment (version 1.1)

prepare.data: Initial Preparations of Bitext before the Word Alignment and the Evaluation of Word Alignment Quality

Description

For a given Sentence-Aligned Parallel Corpus, it prepars sentence pairs as an input for align.ibm1 and evaluation functions in this package.

Usage

prepare.data(file.sorc, file.trgt, n = -1L, 
             encode.sorc = 'unknown' , encode.trgt = 'unknown', 
             min.len = 5, max.len = 40, remove.pt = TRUE, word.align = TRUE)

Arguments

file.sorc

the name of source language file.

file.trgt

the name of target language file.

n

the number of sentences to be read.If -1, it considers all sentences.

encode.sorc

encoding to be assumed for the source language. If the value is "latin1" or "UTF-8" it is used to mark character strings as known to be in Latin-1 or UTF-8. For more details please see scan function.

encode.trgt

encoding to be assumed for the target language. If the value is "latin1" or "UTF-8" it is used to mark character strings as known to be in Latin-1 or UTF-8. For more details please see scan function.

min.len

a minimum length of sentences.

max.len

a maximum length of sentences.

remove.pt

logical. If TRUE, it removes all punctuation marks.

word.align

logical. If FALSE, it divides each sentence into its words. Results can be used in align.symmet, cross.table, align.test and evaluation functions.

Value

A list.

if word_align = TRUE

len1

An integer.

aa

A matrix (n*2), where n is the number of remained sentence pairs after preprocessing.

otherwise,

initial

An integer.

used

An integer.

source.tok

A list of words for each the source sentence.

target.tok

A list of words for each the target sentence.

Details

It balances between source and target language as much as possible. For example, it removes extra blank sentences and equalization sentence pairs. Also, using nfirst2lower function, it converts the first letter of each sentence into lowercase. Moreover, it removes short and long sentences.

References

Koehn P. (2010), "Statistical Machine Translation.", Cambridge University, New York.

See Also

evaluation, nfirst2lower, align.ibm1, scan

Examples

# NOT RUN {
# Since the extraction of  bg-en.tgz in Europarl corpus is time consuming, 
# so the aforementioned unzip files have been temporarily exported to 
# http://www.um.ac.ir/~sarmad/... .
# }
# NOT RUN {
aa1 = prepare.data ('http://www.um.ac.ir/~sarmad/word.a/euro.bg',
                   'http://www.um.ac.ir/~sarmad/word.a/euro.en', 
                    n = 20, encode.sorc = 'UTF-8')
 
aa2 = prepare.data ('http://www.um.ac.ir/~sarmad/word.a/euro.bg',
                   'http://www.um.ac.ir/~sarmad/word.a/euro.en', 
                    n = 20, encode.sorc = 'UTF-8', word.align = FALSE)
                   
aa3 = prepare.data ('http://www.um.ac.ir/~sarmad/word.a/euro.bg',
                   'http://www.um.ac.ir/~sarmad/word.a/euro.en', 
                    n = 20, encode.sorc = 'UTF-8', remove.pt = FALSE)
# }