[2032] - Changed python set to cpp stl set (explosion#2170)

Changed python set to cpp stl set explosion#2032 

## Description

Changed python set to cpp stl set. CPP stl set works better due to the logarithmic run time of its methods. Finding minimum in the cpp set is done in constant time as opposed to the worst case linear runtime of python set. Operations such as find,count,insert,delete are also done in either constant and logarithmic time thus making cpp set a better option to manage vectors.
Reference : http://www.cplusplus.com/reference/set/set/

### Types of change
Enhancement for `Vectors` for faster initialising of word vectors(fasttext)

.github/CONTRIBUTOR_AGREEMENT.md

@@ -91,16 +91,16 @@ mark both statements:
     or entity, including my employer, has or will have rights with respect to my
     contributions.
 
-    * [x] I am signing on behalf of my employer or a legal entity and I have the
+    * [] I am signing on behalf of my employer or a legal entity and I have the
     actual authority to contractually bind that entity.
 
 ## Contributor Details
 
 | Field                          | Entry                |
 |------------------------------- | -------------------- |
-| Name                           |                      |
+| Name                           | Suraj Rajan          |
 | Company name (if applicable)   |                      |
 | Title or role (if applicable)  |                      |
-| Date                           |                      |
-| GitHub username                |                      |
+| Date                           | 31/Mar/2018          |
+| GitHub username                | skrcode              |
 | Website (optional)             |                      |

spacy/tests/vectors/test_vectors.py

@@ -28,12 +28,38 @@ def vectors():
 def data():
     return numpy.asarray([[0.0, 1.0, 2.0], [3.0, -2.0, 4.0]], dtype='f')
 
+@pytest.fixture
+def resize_data():
+    return numpy.asarray([[0.0, 1.0], [2.0, 3.0]], dtype='f')
 
 @pytest.fixture()
 def vocab(en_vocab, vectors):
     add_vecs_to_vocab(en_vocab, vectors)
     return en_vocab
 
+def test_init_vectors_with_resize_shape(strings,resize_data):
+    v = Vectors(shape=(len(strings), 3))
+    v.resize(shape=resize_data.shape)
+    assert v.shape == resize_data.shape
+    assert v.shape != (len(strings), 3)
+
+def test_init_vectors_with_resize_data(data,resize_data):
+    v = Vectors(data=data)
+    v.resize(shape=resize_data.shape)
+    assert v.shape == resize_data.shape
+    assert v.shape != data.shape
+
+def test_get_vector_resize(strings, data,resize_data):
+    v = Vectors(data=data)
+    v.resize(shape=resize_data.shape)
+    strings = [hash_string(s) for s in strings]
+    for i, string in enumerate(strings):
+        v.add(string, row=i)
+
+    assert list(v[strings[0]]) == list(resize_data[0])
+    assert list(v[strings[0]]) != list(resize_data[1])
+    assert list(v[strings[1]]) != list(resize_data[0])
+    assert list(v[strings[1]]) == list(resize_data[1])
 
 def test_init_vectors_with_data(strings, data):
     v = Vectors(data=data)

spacy/vectors.pyx

@@ -16,6 +16,8 @@ from .strings cimport StringStore, hash_string
 from .compat import basestring_, path2str
 from . import util
 
+from cython.operator cimport dereference as deref
+from libcpp.set cimport set as cppset
 
 def unpickle_vectors(bytes_data):
     return Vectors().from_bytes(bytes_data)
@@ -50,7 +52,7 @@ cdef class Vectors:
     cdef public object name
     cdef public object data
     cdef public object key2row
-    cdef public object _unset
+    cdef cppset[int] _unset
 
     def __init__(self, *, shape=None, data=None, keys=None, name=None):
         """Create a new vector store.
@@ -69,9 +71,9 @@ cdef class Vectors:
         self.data = data
         self.key2row = OrderedDict()
         if self.data is not None:
-            self._unset = set(range(self.data.shape[0]))
+            self._unset = cppset[int]({i for i in range(self.data.shape[0])})
         else:
-            self._unset = set()
+            self._unset = cppset[int]()
         if keys is not None:
             for i, key in enumerate(keys):
                 self.add(key, row=i)
@@ -93,7 +95,7 @@ cdef class Vectors:
     @property
     def is_full(self):
         """RETURNS (bool): `True` if no slots are available for new keys."""
-        return len(self._unset) == 0
+        return self._unset.size() == 0
 
     @property
     def n_keys(self):
@@ -124,8 +126,8 @@ cdef class Vectors:
         """
         i = self.key2row[key]
         self.data[i] = vector
-        if i in self._unset:
-            self._unset.remove(i)
+        if self._unset.count(i):
+            self._unset.erase(self._unset.find(i))
 
     def __iter__(self):
         """Iterate over the keys in the table.
@@ -164,7 +166,7 @@ cdef class Vectors:
             xp = get_array_module(self.data)
             self.data = xp.resize(self.data, shape)
         filled = {row for row in self.key2row.values()}
-        self._unset = {row for row in range(shape[0]) if row not in filled}
+        self._unset = cppset[int]({row for row in range(shape[0]) if row not in filled})
         removed_items = []
         for key, row in list(self.key2row.items()):
             if row >= shape[0]:
@@ -188,7 +190,7 @@ cdef class Vectors:
         YIELDS (ndarray): A vector in the table.
         """
         for row, vector in enumerate(range(self.data.shape[0])):
-            if row not in self._unset:
+            if not self._unset.count(row):
                 yield vector
 
     def items(self):
@@ -253,13 +255,13 @@ cdef class Vectors:
         elif row is None:
             if self.is_full:
                 raise ValueError("Cannot add new key to vectors -- full")
-            row = min(self._unset)
+            row = deref(self._unset.begin())
 
         self.key2row[key] = row
         if vector is not None:
             self.data[row] = vector
-            if row in self._unset:
-                self._unset.remove(row)
+            if self._unset.count(row):
+                self._unset.erase(self._unset.find(row))
         return row
 
     def most_similar(self, queries, *, batch_size=1024):
@@ -365,8 +367,8 @@ cdef class Vectors:
                 with path.open('rb') as file_:
                     self.key2row = msgpack.load(file_)
             for key, row in self.key2row.items():
-                if row in self._unset:
-                    self._unset.remove(row)
+                if self._unset.count(row):
+                    self._unset.erase(self._unset.find(row))
 
         def load_keys(path):
             if path.exists():