[TGA] Option to block full context (#2928)

* blcok full context

* black

* unskip test

* change tensor to longtensor

* default is true, use upgrade opt

* add warning

parlai/core/torch_agent.py

@@ -1363,6 +1363,7 @@ def _set_text_vec(self, obs, history, truncate):
             obs['full_text'] = history_string
             if history_string:
                 obs['text_vec'] = history.get_history_vec()
+                obs['full_text_vec'] = history.get_history_vec()
 
         # check truncation
         if obs.get('text_vec') is not None:

parlai/core/torch_generator_agent.py

@@ -368,6 +368,14 @@ def upgrade_opt(cls, opt_from_disk: Opt):
                 ]
             del opt_from_disk['beam_blacklist_filename']
 
+        # 2020-08-04: Introduce full context beam blocking
+        # Previous, specifying --beam-context-block-ngram > 1 would block
+        # from generating ngrams from model's context, which is limited
+        # by truncation parameters. Now, we block on full dialogue history.
+        if 'beam_block_full_context' not in opt_from_disk:
+            warn_once('Loading model with `--beam-block-full-context false`')
+            opt_from_disk['beam_block_full_context'] = False
+
         return opt_from_disk
 
     @classmethod
@@ -403,6 +411,13 @@ def add_cmdline_args(cls, argparser):
             default=-1,
             help='Size n-grams to block in beam search. val <= 0 implies no blocking',
         )
+        agent.add_argument(
+            '--beam-block-full-context',
+            type='bool',
+            default=True,
+            help='Block n-grams from the *full* history context. Specify False to block '
+            'up to m tokens in the past, where m is truncation parameter for agent',
+        )
         agent.add_argument(
             '--beam-length-penalty',
             type=float,
@@ -462,6 +477,7 @@ def __init__(self, opt: Opt, shared=None):
         self.beam_min_length = opt.get('beam_min_length', 1)
         self.beam_block_ngram = opt.get('beam_block_ngram', -1)
         self.beam_context_block_ngram = opt.get('beam_context_block_ngram', -1)
+        self.beam_block_full_context = opt.get('beam_block_full_context', False)
         self.temperature = opt.get('temperature', 1.0)
         assert self.temperature > 0, '--temperature must be greater than 0'
         self.output_token_losses = opt.get('verbose', False)
@@ -981,7 +997,13 @@ def _get_context(self, batch, batch_idx):
 
         Intentionally overridable for more complex model histories.
         """
-        return batch.text_vec[batch_idx]
+        ctxt = batch.text_vec[batch_idx]
+        if self.beam_block_full_context:
+            full_ctxt = batch.observations[batch_idx].get('full_text_vec', ctxt)
+            if not isinstance(full_ctxt, torch.LongTensor):
+                full_ctxt = torch.LongTensor(full_ctxt).to(ctxt)
+            ctxt = full_ctxt
+        return ctxt
 
     def _get_initial_decoder_input(
         self, bsz: int, beam_size: int, dev: torch.device

tests/test_tga.py

@@ -6,7 +6,6 @@
 """
 Test TorchGeneratorAgent.
 """
-
 import unittest
 from parlai.core.agents import create_agent
 import parlai.utils.testing as testing_utils
@@ -78,6 +77,70 @@ def test_file_inference(self):
         agent = create_agent(opt, True)
         self.assertEqual(agent.opt['inference'], 'beam')
 
+    def test_block_full_context(self):
+        """
+        Test --beam-block-full-context with older model files.
+        """
+        # old model file == beam block full context false
+        pp = ParlaiParser(True, True)
+        opt = pp.parse_args(
+            ['--model-file', 'zoo:unittest/transformer_generator2/model']
+        )
+        agent = create_agent(opt, True)
+        self.assertEqual(agent.opt['beam_block_full_context'], False)
+        self.assertEqual(agent.beam_block_full_context, False)
+
+        # brand new model == beam block full context true
+        pp = ParlaiParser(True, True)
+        opt = pp.parse_args(['--model', 'transformer/generator'])
+        agent = create_agent(opt, True)
+        self.assertEqual(agent.opt['beam_block_full_context'], True)
+        self.assertEqual(agent.beam_block_full_context, True)
+
+
+class TestTreeSearch(unittest.TestCase):
+    """
+    Tests various Tree Search functionalities.
+
+    NOTE: Currently incomplete.
+    """
+
+    def test_full_context_block(self):
+        args = [
+            '--model-file',
+            'zoo:unittest/transformer_generator2/model',
+            '--inference',
+            'beam',
+            '--truncate',
+            '1024',
+        ]
+        pp = ParlaiParser(True, True)
+        agent = create_agent(pp.parse_args(args), True)
+        obs = {'text': '1 2 3 4 ' * 256, 'episode_done': False}
+        agent.observe(obs)
+        batch = agent.batchify([agent.observation])
+        self.assertEqual(agent._get_context(batch, 0).tolist(), [5, 4, 6, 7] * 256)
+
+        # observe 1 more obs, context is the same (truncation)
+        agent.observe(obs)
+        batch = agent.batchify([agent.observation])
+        self.assertEqual(agent._get_context(batch, 0).tolist(), [5, 4, 6, 7] * 256)
+
+        # Now, set agent's beam_block_full_context
+        args += ['--beam-block-full-context', 'true']
+        agent2 = create_agent(pp.parse_args(args), True)
+        agent2.observe(obs)
+        batch = agent2.batchify([agent2.observation])
+        self.assertEqual(agent2._get_context(batch, 0).tolist(), [5, 4, 6, 7] * 256)
+
+        # observe 1 more obs, context is larger now
+        agent2.observe(obs)
+        batch = agent2.batchify([agent2.observation])
+        self.assertEqual(
+            agent2._get_context(batch, 0).tolist(),
+            [5, 4, 6, 7] * 256 + [3] + [5, 4, 6, 7] * 256,
+        )  # 3 is end token.
+
 
 if __name__ == '__main__':
     unittest.main()