Revert "Randomly initialize new embedding vectors when updating vocab…

…ulary (#499)"

This reverts commit 1b3cf14.

opennmt/tests/checkpoint_test.py

@@ -38,12 +38,10 @@ def testVocabMappingReplace(self):
 
   def testVocabVariableUpdate(self):
     mapping = [0, -1, -1, 2, -1, 4]
-    old = np.array([1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0])
+    old = np.array([1, 2, 3, 4, 5, 6, 7])
     vocab_size = 7
     new = checkpoint._update_vocabulary_variable(old, vocab_size, mapping)
-    for index, value in zip(mapping, new):
-      if index >= 0:
-        self.assertEqual(value, old[index])
+    self.assertAllEqual([1, 0, 0, 3, 0, 5], new)
 
   def _generateCheckpoint(self,
                           model_dir,

opennmt/utils/checkpoint.py

@@ -42,7 +42,7 @@ def _update_vocabulary_variable(variable, vocab_size, mapping):
   variable_t = np.transpose(variable, axes=perm)
   new_shape = list(variable_t.shape)
   new_shape[0] = len(mapping)
-  new_variable_t = np.random.uniform(-1.0, 1.0, size=new_shape).astype(variable.dtype)
+  new_variable_t = np.zeros(new_shape, dtype=variable.dtype)
   for i, j in enumerate(mapping):
     if j >= 0:
       new_variable_t[i] = variable_t[j]