* POS tag memoisation working, with good speed-up

spacy/en.pyx

@@ -32,8 +32,10 @@ provides a fully Penn Treebank 3-compliant tokenizer.
 '''
 from __future__ import unicode_literals
 
+from murmurhash.mrmr cimport hash64
+
 cimport lang
-from .typedefs cimport flags_t
+from .typedefs cimport hash_t, id_t, flags_t
 import orth
 from .morphology cimport NO_TAG, ADJ, ADV, ADP, CONJ, DET, NOUN, NUM, PRON, PRT, VERB
 from .morphology cimport X, PUNCT, EOL
@@ -41,6 +43,9 @@ from .morphology cimport X, PUNCT, EOL
 from .tokens cimport Morphology
 
 
+DEF USE_POS_CACHE = True
+
+
 POS_TAGS = {
     'NULL': (NO_TAG, {}),
     'EOL': (EOL, {}),
@@ -134,6 +139,20 @@ cdef class English(Language):
         name (unicode): The two letter code used by Wikipedia for the language.
         lexicon (Lexicon): The lexicon. Exposes the lookup method.
     """
+    def load_pos_cache(self, loc):
+        cdef int i = 0
+        cdef hash_t key
+        cdef int pos
+        with open(loc) as file_:
+            for line in file_:
+                pieces = line.split()
+                if i >= 500000:
+                    break
+                i += 1
+                key = int(pieces[1])
+                pos = int(pieces[2])
+                self._pos_cache.set(key, <void*>pos)
+
     def get_props(self, unicode string):
         return {'flags': self.set_flags(string), 'dense': orth.word_shape(string)}
 
@@ -156,11 +175,19 @@ cdef class English(Language):
         cdef int i
         cdef atom_t[N_CONTEXT_FIELDS] context
         cdef TokenC* t = tokens.data
+        cdef id_t[2] bigram
+        cdef hash_t cache_key
+        cdef void* cached = NULL
         assert self.morphologizer is not None
         cdef dict tagdict = self.pos_tagger.tagdict
         for i in range(tokens.length):
-            if t[i].lex.sic in tagdict:
-                t[i].pos = tagdict[t[i].lex.sic]
+            if USE_POS_CACHE:
+                bigram[0] = tokens.data[i].lex.sic
+                bigram[1] = tokens.data[i-1].lex.sic
+                cache_key = hash64(bigram, sizeof(id_t) * 2, 0)
+                cached = self._pos_cache.get(cache_key)
+            if cached != NULL:
+                t[i].pos = <int><size_t>cached
             else:
                 fill_pos_context(context, i, t)
                 t[i].pos = self.pos_tagger.predict(context)

spacy/lang.pxd

@@ -44,6 +44,7 @@ cdef class Language:
     cpdef readonly Tagger pos_tagger
     cpdef readonly Morphologizer morphologizer
 
+    cdef PreshMap _pos_cache
     cdef object _prefix_re
     cdef object _suffix_re
     cdef object _infix_re

spacy/lang.pyx

@@ -34,6 +34,7 @@ cdef class Language:
         self.mem = Pool()
         self._cache = PreshMap(2 ** 25)
         self._specials = PreshMap(2 ** 16)
+        self._pos_cache = PreshMap(2 ** 16)
         rules, prefix, suffix, infix = util.read_lang_data(name)
         self._prefix_re = re.compile(prefix)
         self._suffix_re = re.compile(suffix)
@@ -50,6 +51,7 @@ cdef class Language:
             self.pos_tagger = Tagger(path.join(util.DATA_DIR, self.name, 'pos'))
             self.morphologizer = Morphologizer(self.lexicon.strings,
                                     path.join(util.DATA_DIR, self.name))
+            self.load_pos_cache(path.join(util.DATA_DIR, self.name, 'pos', 'bigram_cache_2m'))
 
     cpdef Tokens tokens_from_list(self, list strings):
         cdef int length = sum([len(s) for s in strings])