From a530ae218c7a76c44124e1f80abd84dbd4a4901a Mon Sep 17 00:00:00 2001
From: m-yoshinaka <49668018+m-yoshinaka@users.noreply.github.com>
Date: Tue, 19 Jan 2021 08:30:30 +0000
Subject: [PATCH] [add] Add a variation of SAPPHIRE with chunker

---
 sapphire/sapphire_with_chunker.py | 128 ++++++++++++++++++++++++++++++
 1 file changed, 128 insertions(+)
 create mode 100644 sapphire/sapphire_with_chunker.py

diff --git a/sapphire/sapphire_with_chunker.py b/sapphire/sapphire_with_chunker.py
new file mode 100644
index 0000000..b1a21dc
--- /dev/null
+++ b/sapphire/sapphire_with_chunker.py
@@ -0,0 +1,128 @@
+import re
+from nltk_opennlp.taggers import OpenNLPTagger
+from nltk_opennlp.chunkers import OpenNLPChunker
+
+from .sapphire import Sapphire
+from .word_alignment import get_similarity_matrix
+
+
+class SapphireWithChunker(Sapphire):
+
+    def __init__(self, model, pyopennlp_dir):
+        super().__init__(model)
+
+        path_to_bin = pyopennlp_dir + '/apache-opennlp/bin'
+        path_to_tagger = pyopennlp_dir + '/opennlp_models/en-pos-maxent.bin'
+        path_to_chunker = pyopennlp_dir + '/opennlp_models/en-chunker.bin'
+        self.chunker = Chunker(path_to_bin=path_to_bin,
+                               path_to_tagger=path_to_tagger,
+                               path_to_chunker=path_to_chunker)
+
+    def align(self, tokens_src, tokens_trg):
+        len_src = len(tokens_src)
+        len_trg = len(tokens_trg)
+
+        tokens_src, chunks_src = self.chunker(tokens_src)
+        tokens_trg, chunks_trg = self.chunker(tokens_trg)
+
+        if tokens_src is None or tokens_trg is None:
+            if self.get_score:
+                return [], ([], 0)
+            else:
+                return [], []
+
+        vectors_src = self.vectorizer(tokens_src)
+        vectors_trg = self.vectorizer(tokens_trg)
+
+        sim_matrix = get_similarity_matrix(vectors_src, vectors_trg)
+        word_alignment = self.word_aligner(sim_matrix)
+
+        phrase_pairs = self.extractor(word_alignment, vectors_src, vectors_trg)
+        phrase_pairs = self._filter_out_by_chunk(chunks_src, chunks_trg,
+                                                 phrase_pairs)
+        phrase_alignment = self.phrase_aligner(phrase_pairs, len_src, len_trg)
+
+        return word_alignment, phrase_alignment
+
+    def _filter_out_by_chunk(self, chunks_src, chunks_trg, phrase_pairs):
+        new_phrase_paris = []
+        for ss, se, ts, te, score in phrase_pairs:
+            is_ok = True
+            for cnk in chunks_src:
+                if self._conflict_with_chunk(ss, se, cnk):
+                    is_ok = False
+                    break
+            if is_ok:
+                for cnk in chunks_trg:
+                    if self._conflict_with_chunk(ts, te, cnk):
+                        is_ok = False
+                        break
+            if is_ok:
+                new_phrase_paris.append((ss, se, ts, te, score))
+
+        return new_phrase_paris
+
+    @staticmethod
+    def _conflict_with_chunk(start, end, chunk):
+        if len(chunk) < 1:
+            return False
+        elif start == end and chunk[0] <= start <= chunk[-1]:
+            return True
+        elif chunk[0] < start <= chunk[-1]:
+            return True
+        elif chunk[0] <= end < chunk[-1]:
+            return True
+        return False
+
+
+class Chunker(object):
+
+    def __init__(self, path_to_bin, path_to_tagger, path_to_chunker):
+        self.tagger = OpenNLPTagger(path_to_bin=path_to_bin,
+                                    path_to_model=path_to_tagger)
+        self.chunker = OpenNLPChunker(path_to_bin=path_to_bin,
+                                      path_to_chunker=path_to_chunker,
+                                      use_punc_tag=True)
+
+    def __call__(self, sentence: list):
+        return self.chunking(sentence)
+
+    def chunking(self, sentence: list):
+        sentence = ' '.join(sentence)
+        tokens = self.tagger.tag(sentence)
+
+        try:
+            tree = self.chunker.parse(tokens)
+        except (TypeError, IndexError, AttributeError):
+            return None, None
+
+        chunks = self._tree2chunk(tree)
+        chunks = self._chunk2index(chunks)
+        tokens = [t[0] for t in tokens]
+        return tokens, chunks
+
+    @ staticmethod
+    def _tree2chunk(tree):
+        tree_text = str(tree).split('\n')
+        tree_text = [c.strip() for c in tree_text][1:]
+        chunks = []
+        for cnk in tree_text[:]:
+            if cnk[0] == '(':
+                cnk = cnk[1:]
+            if cnk[-1] == ')':
+                cnk = cnk[:-1]
+            cnk = cnk.split()
+            cnk = tuple(c for c in cnk if re.fullmatch(r'[A-Z]+', c) is None)
+            chunks.append(cnk)
+        return chunks
+
+    @ staticmethod
+    def _chunk2index(chunks):
+        chunk_index = []
+        i = 1
+        for cnk in chunks:
+            c_len = len(cnk)
+            index = tuple(j for j in range(i, i + c_len))
+            chunk_index.append(index)
+            i += c_len
+        return chunk_index