From ca1276477289b570249967d595f232225df90184 Mon Sep 17 00:00:00 2001
From: Matthew Honnibal <honnibal+gh@gmail.com>
Date: Thu, 5 Oct 2017 21:53:29 -0500
Subject: [PATCH] Enable history features for beam parser

---
 spacy/syntax/_beam_utils.pyx | 11 ++++++++---
 spacy/syntax/nn_parser.pyx   | 11 +++++++++--
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/spacy/syntax/_beam_utils.pyx b/spacy/syntax/_beam_utils.pyx
index a26900f6b..da4efefbc 100644
--- a/spacy/syntax/_beam_utils.pyx
+++ b/spacy/syntax/_beam_utils.pyx
@@ -21,6 +21,7 @@ cdef int _transition_state(void* _dest, void* _src, class_t clas, void* _moves)
     moves = <const Transition*>_moves
     dest.clone(src)
     moves[clas].do(dest.c, moves[clas].label)
+    dest.c.push_hist(clas)
 
 
 cdef int _check_final_state(void* _state, void* extra_args) except -1:
@@ -148,8 +149,8 @@ def get_token_ids(states, int n_tokens):
 nr_update = 0
 def update_beam(TransitionSystem moves, int nr_feature, int max_steps,
                 states, golds,
-                state2vec, vec2scores, 
-                int width, float density,
+                state2vec, vec2scores,
+                int width, float density, int hist_feats,
                 losses=None, drop=0.):
     global nr_update
     cdef MaxViolation violn
@@ -180,7 +181,11 @@ def update_beam(TransitionSystem moves, int nr_feature, int max_steps,
         # Now that we have our flat list of states, feed them through the model
         token_ids = get_token_ids(states, nr_feature)
         vectors, bp_vectors = state2vec.begin_update(token_ids, drop=drop)
-        scores, bp_scores = vec2scores.begin_update(vectors, drop=drop)
+        if hist_feats:
+            hists = numpy.asarray([st.history[:hist_feats] for st in states], dtype='i')
+            scores, bp_scores = vec2scores.begin_update((vectors, hists), drop=drop)
+        else:
+            scores, bp_scores = vec2scores.begin_update(vectors, drop=drop)
 
         # Store the callbacks for the backward pass
         backprops.append((token_ids, bp_vectors, bp_scores))
diff --git a/spacy/syntax/nn_parser.pyx b/spacy/syntax/nn_parser.pyx
index b57e8b466..9a071ae14 100644
--- a/spacy/syntax/nn_parser.pyx
+++ b/spacy/syntax/nn_parser.pyx
@@ -505,7 +505,12 @@ cdef class Parser:
                         states.append(stcls)
                 token_ids = self.get_token_ids(states)
                 vectors = state2vec(token_ids)
-                scores = vec2scores(vectors)
+                if self.cfg.get('hist_size', 0):
+                    hists = numpy.asarray([st.history[:self.cfg['hist_size']]
+                                           for st in states], dtype='i')
+                    scores = vec2scores(vectors, drop=drop)
+                else:
+                    scores = vec2scores(vectors, drop=drop)
                 j = 0
                 c_scores = <float*>scores.data
                 for i in range(beam.size):
@@ -537,6 +542,7 @@ cdef class Parser:
         guess = arg_maxout_if_valid(scores, is_valid, nr_class, nr_piece)
         action = self.moves.c[guess]
         action.do(state, action.label)
+        state.push_hist(guess)
 
         free(is_valid)
         free(scores)
@@ -634,7 +640,7 @@ cdef class Parser:
         states_d_scores, backprops = _beam_utils.update_beam(self.moves, self.nr_feature, 500,
                                         states, golds,
                                         state2vec, vec2scores,
-                                        width, density,
+                                        width, density, self.cfg.get('hist_size', 0),
                                         drop=drop, losses=losses)
         backprop_lower = []
         cdef float batch_size = len(docs)
@@ -967,6 +973,7 @@ cdef int _transition_state(void* _dest, void* _src, class_t clas, void* _moves)
     moves = <const Transition*>_moves
     dest.clone(src)
     moves[clas].do(dest.c, moves[clas].label)
+    dest.c.push_hist(clas)
 
 
 cdef int _check_final_state(void* _state, void* extra_args) except -1: