Merge internal changes (#136)

Changes:
- 7d19e36: Add `--sampling` flag to generate.py to sample instead of doing beam search
- c777340: Add `scripts/average_checkpoints.py` to average multiple checkpoints into a combined model
- 3ea882c: Add `--max-update` option to train.py to stop training after a given number of updates
- small bugfixes for distributed training, LSTM, inverse square root LR scheduler

fairseq/criterions/cross_entropy.py

@@ -8,9 +8,11 @@
 import math
 import torch.nn.functional as F
 
-from . import FairseqCriterion, register_criterion
 from fairseq import utils
 
+from . import FairseqCriterion, register_criterion
+
+
 @register_criterion('cross_entropy')
 class CrossEntropyCriterion(FairseqCriterion):
 
@@ -28,7 +30,7 @@ class CrossEntropyCriterion(FairseqCriterion):
         net_output = model(**sample['net_input'])
         lprobs = model.get_normalized_probs(net_output, log_probs=True)
         lprobs = lprobs.view(-1, lprobs.size(-1))
-        target = sample['target'].view(-1)
+        target = model.get_targets(sample, net_output).view(-1)
         loss = F.nll_loss(lprobs, target, size_average=False, ignore_index=self.padding_idx,
                           reduce=reduce)
         sample_size = sample['target'].size(0) if self.args.sentence_avg else sample['ntokens']
@@ -47,6 +49,7 @@ class CrossEntropyCriterion(FairseqCriterion):
         sample_size = sum(log.get('sample_size', 0) for log in logging_outputs)
         agg_output = {
             'loss': loss_sum / sample_size / math.log(2),
+            'sample_size': sample_size,
         }
         if sample_size != ntokens:
             agg_output['nll_loss'] = loss_sum / ntokens / math.log(2)

fairseq/criterions/label_smoothed_cross_entropy.py

@@ -6,8 +6,6 @@
 # can be found in the PATENTS file in the same directory.
 
 import math
-import torch
-import torch.nn.functional as F
 
 from fairseq import utils
 
@@ -37,7 +35,8 @@ class LabelSmoothedCrossEntropyCriterion(FairseqCriterion):
         """
         net_output = model(**sample['net_input'])
         lprobs = model.get_normalized_probs(net_output, log_probs=True)
-        target = sample['target'].unsqueeze(-1)
+        lprobs = lprobs.view(-1, lprobs.size(-1))
+        target = model.get_targets(sample, net_output).view(-1, 1)
         non_pad_mask = target.ne(self.padding_idx)
         nll_loss = -lprobs.gather(dim=-1, index=target)[non_pad_mask]
         smooth_loss = -lprobs.sum(dim=-1, keepdim=True)[non_pad_mask]
@@ -64,4 +63,5 @@ class LabelSmoothedCrossEntropyCriterion(FairseqCriterion):
         return {
             'loss': sum(log.get('loss', 0) for log in logging_outputs) / sample_size / math.log(2),
             'nll_loss': sum(log.get('nll_loss', 0) for log in logging_outputs) / ntokens / math.log(2),
+            'sample_size': sample_size,
         }

fairseq/data.py

@@ -198,7 +198,7 @@ class LanguagePairDataset(torch.utils.data.Dataset):
     def __getitem__(self, i):
         # subtract 1 for 0-based indexing
         source = self.src[i].long() - 1
-        res = { 'id': i, 'source': source }
+        res = {'id': i, 'source': source}
         if self.dst:
             res['target'] = self.dst[i].long() - 1
 
@@ -283,9 +283,9 @@ def _valid_size(src_size, dst_size, max_positions):
         max_src_positions, max_dst_positions = max_positions, max_positions
     else:
         max_src_positions, max_dst_positions = max_positions
-    if src_size < 2 or src_size > max_src_positions:
+    if src_size < 1 or src_size > max_src_positions:
         return False
-    if dst_size is not None and (dst_size < 2 or dst_size > max_dst_positions):
+    if dst_size is not None and (dst_size < 1 or dst_size > max_dst_positions):
         return False
     return True
 

fairseq/dictionary.py

@@ -6,6 +6,7 @@
 # can be found in the PATENTS file in the same directory.
 
 import math
+import os
 import torch
 
 
@@ -23,6 +24,9 @@ class Dictionary(object):
         self.unk_index = self.add_symbol(unk)
         self.nspecial = len(self.symbols)
 
+    def __eq__(self, other):
+        return self.indices == other.indices
+
     def __getitem__(self, idx):
         if idx < len(self.symbols):
             return self.symbols[idx]
@@ -97,8 +101,8 @@ class Dictionary(object):
         """Helper to get index of unk symbol"""
         return self.unk_index
 
-    @staticmethod
-    def load(f):
+    @classmethod
+    def load(cls, f):
         """Loads the dictionary from a text file with the format:
 
         ```
@@ -111,14 +115,14 @@ class Dictionary(object):
         if isinstance(f, str):
             try:
                 with open(f, 'r', encoding='utf-8') as fd:
-                    return Dictionary.load(fd)
+                    return cls.load(fd)
             except FileNotFoundError as fnfe:
                 raise fnfe
             except Exception:
                 raise Exception("Incorrect encoding detected in {}, please "
                                 "rebuild the dataset".format(f))
 
-        d = Dictionary()
+        d = cls()
         for line in f.readlines():
             idx = line.rfind(' ')
             word = line[:idx]
@@ -131,6 +135,7 @@ class Dictionary(object):
     def save(self, f, threshold=3, nwords=-1):
         """Stores dictionary into a text file"""
         if isinstance(f, str):
+            os.makedirs(os.path.dirname(f), exist_ok=True)
             with open(f, 'w', encoding='utf-8') as fd:
                 return self.save(fd, threshold, nwords)
         cnt = 0

fairseq/distributed_utils.py

@@ -10,6 +10,12 @@ import pickle
 
 import torch.distributed
 
+from fairseq import utils
+
+
+def is_master(args):
+    return args.distributed_rank == 0
+
 
 def distributed_init(args):
     if args.distributed_world_size == 1:
@@ -27,7 +33,7 @@ def distributed_init(args):
             world_size=args.distributed_world_size)
 
     args.distributed_rank = torch.distributed.get_rank()
-    if args.distributed_rank != 0:
+    if not is_master(args):
         suppress_output()
 
     return args.distributed_rank
@@ -104,7 +110,7 @@ def all_gather_list(data, max_size=4096):
     world_size = torch.distributed.get_world_size()
     if not hasattr(all_gather_list, '_in_buffer') or \
             max_size != all_gather_list._in_buffer.size():
-        all_gather_list._in_buffer = torch.ByteTensor(max_size)
+        all_gather_list._in_buffer = torch.cuda.ByteTensor(max_size)
         all_gather_list._out_buffers = [
             torch.cuda.ByteTensor(max_size)
             for i in range(world_size)
@@ -113,18 +119,21 @@ def all_gather_list(data, max_size=4096):
     out_buffers = all_gather_list._out_buffers
 
     enc = pickle.dumps(data)
-    if len(enc) >= max_size:
-        raise ValueError('encoded data exceeds max_size: {}'.format(len(enc)))
-    in_buffer[0] = len(enc)
-    in_buffer[1:len(enc)+1] = torch.ByteTensor(list(enc))
+    enc_size = len(enc)
+    if enc_size + 2 > max_size:
+        raise ValueError('encoded data exceeds max_size: {}'.format(enc_size + 2))
+    assert max_size < 255*256
+    in_buffer[0] = enc_size // 255  # this encoding works for max_size < 65k
+    in_buffer[1] = enc_size % 255
+    in_buffer[2:enc_size+2] = torch.ByteTensor(list(enc))
 
     torch.distributed.all_gather(out_buffers, in_buffer.cuda())
 
     result = []
     for i in range(world_size):
         out_buffer = out_buffers[i]
-        size = out_buffer[0]
+        size = (255 * utils.item(out_buffer[0])) + utils.item(out_buffer[1])
         result.append(
-            pickle.loads(bytes(out_buffer[1:size+1].tolist()))
+            pickle.loads(bytes(out_buffer[2:size+2].tolist()))
         )
     return result

fairseq/indexed_dataset.py

@@ -107,10 +107,12 @@ class IndexedRawTextDataset(IndexedDataset):
     """Takes a text file as input and binarizes it in memory at instantiation.
     Original lines are also kept in memory"""
 
-    def __init__(self, path, dictionary):
+    def __init__(self, path, dictionary, append_eos=True, reverse_order=False):
         self.tokens_list = []
         self.lines = []
         self.sizes = []
+        self.append_eos = append_eos
+        self.reverse_order = reverse_order
         self.read_data(path, dictionary)
         self.size = len(self.tokens_list)
 
@@ -118,8 +120,10 @@ class IndexedRawTextDataset(IndexedDataset):
         with open(path, 'r') as f:
             for line in f:
                 self.lines.append(line.strip('\n'))
-                # +1 for Lua compatibility
-                tokens = Tokenizer.tokenize(line, dictionary, add_if_not_exist=False) + 1
+                tokens = Tokenizer.tokenize(
+                    line, dictionary, add_if_not_exist=False,
+                    append_eos=self.append_eos, reverse_order=self.reverse_order,
+                ) + 1  # +1 for Lua compatibility
                 self.tokens_list.append(tokens)
                 self.sizes.append(len(tokens))
         self.sizes = np.array(self.sizes)

fairseq/models/fairseq_decoder.py

@@ -21,12 +21,11 @@ class FairseqDecoder(nn.Module):
 
     def get_normalized_probs(self, net_output, log_probs):
         """Get normalized probabilities (or log probs) from a net's output."""
-        vocab = net_output.size(-1)
-        net_output1 = net_output.view(-1, vocab)
+        logits = net_output[0]
         if log_probs:
-            return F.log_softmax(net_output1, dim=1).view_as(net_output)
+            return F.log_softmax(logits, dim=-1)
         else:
-            return F.softmax(net_output1, dim=1).view_as(net_output)
+            return F.softmax(logits, dim=-1)
 
     def max_positions(self):
         """Maximum input length supported by the decoder."""

fairseq/models/fairseq_model.py

@@ -41,13 +41,17 @@ class FairseqModel(nn.Module):
 
     def forward(self, src_tokens, src_lengths, prev_output_tokens):
         encoder_out = self.encoder(src_tokens, src_lengths)
-        decoder_out, _ = self.decoder(prev_output_tokens, encoder_out)
+        decoder_out = self.decoder(prev_output_tokens, encoder_out)
         return decoder_out
 
     def get_normalized_probs(self, net_output, log_probs):
         """Get normalized probabilities (or log probs) from a net's output."""
         return self.decoder.get_normalized_probs(net_output, log_probs)
 
+    def get_targets(self, sample, net_output):
+        """Get targets from either the sample or the net's output."""
+        return sample['target']
+
     def max_encoder_positions(self):
         """Maximum input length supported by the encoder."""
         return self.encoder.max_positions()

fairseq/models/fconv.py

@@ -48,6 +48,11 @@ class FConvModel(FairseqModel):
     @classmethod
     def build_model(cls, args, src_dict, dst_dict):
         """Build a new model instance."""
+        if not hasattr(args, 'max_source_positions'):
+            args.max_source_positions = args.max_positions
+            args.max_target_positions = args.max_positions
+        if not hasattr(args, 'share_input_output_embed'):
+            args.share_input_output_embed = False
         encoder = FConvEncoder(
             src_dict,
             embed_dim=args.encoder_embed_dim,

fairseq/models/lstm.py

@@ -65,7 +65,7 @@ class LSTMModel(FairseqModel):
             embed_dim=args.decoder_embed_dim,
             out_embed_dim=args.decoder_out_embed_dim,
             num_layers=args.decoder_layers,
-            attention=bool(args.decoder_attention),
+            attention=bool(eval(args.decoder_attention)),
             dropout_in=args.decoder_dropout_in,
             dropout_out=args.decoder_dropout_out,
         )
@@ -178,7 +178,7 @@ class LSTMDecoder(FairseqIncrementalDecoder):
             LSTMCell(encoder_embed_dim + embed_dim if layer == 0 else embed_dim, embed_dim)
             for layer in range(num_layers)
         ])
-        self.attention = AttentionLayer(encoder_embed_dim, embed_dim)
+        self.attention = AttentionLayer(encoder_embed_dim, embed_dim) if attention else None
         if embed_dim != out_embed_dim:
             self.additional_fc = Linear(embed_dim, out_embed_dim)
         self.fc_out = Linear(out_embed_dim, num_embeddings, dropout=dropout_out)
@@ -229,7 +229,10 @@ class LSTMDecoder(FairseqIncrementalDecoder):
                 prev_cells[i] = cell
 
             # apply attention using the last layer's hidden state
-            out, attn_scores[:, j, :] = self.attention(hidden, encoder_outs)
+            if self.attention is not None:
+                out, attn_scores[:, j, :] = self.attention(hidden, encoder_outs)
+            else:
+                out = hidden
             out = F.dropout(out, p=self.dropout_out, training=self.training)
 
             # input feeding

fairseq/modules/conv_tbc.py

@@ -8,8 +8,6 @@
 import torch
 from torch.nn.modules.utils import _single
 
-from fairseq import utils
-
 
 class ConvTBC(torch.nn.Module):
     """1D convolution over an input of shape (time x batch x channel)

fairseq/modules/learned_positional_embedding.py

@@ -5,10 +5,11 @@
 # the root directory of this source tree. An additional grant of patent rights
 # can be found in the PATENTS file in the same directory.
 
-import torch
 from torch.autograd import Variable
 import torch.nn as nn
 
+from fairseq import utils
+
 
 class LearnedPositionalEmbedding(nn.Embedding):
     """This module learns positional embeddings up to a fixed maximum size.
@@ -25,27 +26,11 @@ class LearnedPositionalEmbedding(nn.Embedding):
         """Input is expected to be of size [bsz x seqlen]."""
         if incremental_state is not None:
             # positions is the same for every token when decoding a single step
-            positions = Variable(
-                input.data.new(1, 1).fill_(self.padding_idx + input.size(1)))
+            positions = input.data.new(1, 1).fill_(self.padding_idx + input.size(1))
         else:
-            positions = Variable(self.make_positions(input.data))
-        return super().forward(positions)
+            positions = utils.make_positions(input.data, self.padding_idx, self.left_pad)
+        return super().forward(Variable(positions))
 
     def max_positions(self):
         """Maximum number of supported positions."""
         return self.num_embeddings - self.padding_idx - 1
-
-    def make_positions(self, input):
-        """Replace non-padding symbols with their position numbers."""
-        if not hasattr(self, 'range_buf'):
-            self.range_buf = input.new()
-        seqlen = input.size(1)
-        if self.range_buf.numel() < seqlen:
-            # offset positions by the padding index
-            torch.arange(self.padding_idx + 1, self.padding_idx + 1 + seqlen,
-                         out=self.range_buf)
-        mask = input.ne(self.padding_idx)
-        positions = self.range_buf[:seqlen].expand_as(input)
-        if self.left_pad:
-            positions = positions - mask.size(1) + mask.long().sum(dim=1).unsqueeze(1)
-        return input.clone().masked_scatter_(mask, positions[mask])

fairseq/optim/__init__.py

@@ -16,6 +16,7 @@ OPTIMIZER_CLASS_NAMES = set()
 
 
 def build_optimizer(args, params):
+    params = filter(lambda p: p.requires_grad, params)
     return OPTIMIZER_REGISTRY[args.optimizer](args, params)
 
 

fairseq/optim/adam.py

@@ -23,6 +23,8 @@ class FairseqAdam(FairseqOptimizer):
         """Add optimizer-specific arguments to the parser."""
         parser.add_argument('--adam-betas', default='(0.9, 0.999)', metavar='B',
                             help='betas for Adam optimizer')
+        parser.add_argument('--adam-eps', type=float, default=1e-8, metavar='D',
+                            help='epsilon for Adam optimizer')
 
     @property
     def optimizer_config(self):
@@ -35,6 +37,7 @@ class FairseqAdam(FairseqOptimizer):
         return {
             'lr': self.args.lr[0],
             'betas': eval(self.args.adam_betas),
+            'eps': self.args.adam_eps,
             'weight_decay': self.args.weight_decay,
         }
 

fairseq/optim/lr_scheduler/inverse_square_root_schedule.py

@@ -69,7 +69,7 @@ class InverseSquareRootSchedule(FairseqLRScheduler):
     def step_update(self, num_updates):
         """Update the learning rate after each update."""
         if num_updates < self.args.warmup_updates:
-            self.lr += self.lr_step
+            self.lr = self.args.warmup_init_lr + num_updates*self.lr_step
         else:
             self.lr = self.decay_factor * num_updates**-0.5
         self.optimizer.set_lr(self.lr)

fairseq/options.py

@@ -32,11 +32,12 @@ def get_generation_parser():
     return parser
 
 
-def parse_args_and_arch(parser, _args=None):
+def parse_args_and_arch(parser, input_args=None):
     # The parser doesn't know about model/criterion/optimizer-specific args, so
     # we parse twice. First we parse the model/criterion/optimizer, then we
     # parse a second time after adding the *-specific arguments.
-    args, _ = parser.parse_known_args(_args)
+    # If input_args is given, we will parse those args instead of sys.argv.
+    args, _ = parser.parse_known_args(input_args)
 
     # Add model-specific args to parser.
     model_specific_group = parser.add_argument_group(
@@ -53,7 +54,7 @@ def parse_args_and_arch(parser, _args=None):
     LR_SCHEDULER_REGISTRY[args.lr_scheduler].add_args(parser)
 
     # Parse a second time.
-    args = parser.parse_args(_args)
+    args = parser.parse_args(input_args)
 
     # Post-process args.
     args.lr = list(map(float, args.lr.split(',')))
@@ -140,6 +141,8 @@ def add_optimization_args(parser):
     group = parser.add_argument_group('Optimization')
     group.add_argument('--max-epoch', '--me', default=0, type=int, metavar='N',
                        help='force stop training at specified epoch')
+    group.add_argument('--max-update', '--mu', default=0, type=int, metavar='N',
+                       help='force stop training at specified update')
     group.add_argument('--clip-norm', default=25, type=float, metavar='NORM',
                        help='clip threshold of gradients')
     group.add_argument('--sentence-avg', action='store_true',
@@ -188,12 +191,14 @@ def add_checkpoint_args(parser):
                        help='don\'t save models and checkpoints')
     group.add_argument('--no-epoch-checkpoints', action='store_true',
                        help='only store last and best checkpoints')
+    group.add_argument('--validate-interval', type=int, default=1, metavar='N',
+                       help='validate every N epochs')
     return group
 
 
 def add_generation_args(parser):
     group = parser.add_argument_group('Generation')
-    group.add_argument('--path', metavar='FILE', required=True, action='append',
+    group.add_argument('--path', metavar='FILE', action='append',
                        help='path(s) to model file(s)')
     group.add_argument('--beam', default=5, type=int, metavar='N',
                        help='beam size')
@@ -228,6 +233,8 @@ def add_generation_args(parser):
                        help='just score the reference translation')
     group.add_argument('--prefix-size', default=0, type=int, metavar='PS',
                        help=('initialize generation by target prefix of given length'))
+    group.add_argument('--sampling', action='store_true',
+                       help='sample hypotheses instead of using beam search')
     return group
 
 

fairseq/progress_bar.py

@@ -107,9 +107,9 @@ class json_progress_bar(progress_bar):
             yield obj
             if self.stats is not None and i > 0 and \
                     self.log_interval is not None and i % self.log_interval == 0:
-                update = self.epoch + float(i / size) if self.epoch is not None else None
+                update = self.epoch - 1 + float(i / size) if self.epoch is not None else None
                 stats = self._format_stats(self.stats, epoch=self.epoch, update=update)
-                print('sweep_log: ' + json.dumps(stats), flush=True)
+                print(json.dumps(stats), flush=True)
 
     def log(self, stats):
         """Log intermediate stats according to log_interval."""

fairseq/sequence_generator.py

@@ -15,7 +15,7 @@ from fairseq.models import FairseqIncrementalDecoder
 class SequenceGenerator(object):
     def __init__(self, models, beam_size=1, minlen=1, maxlen=None,
                  stop_early=True, normalize_scores=True, len_penalty=1,
-                 unk_penalty=0, retain_dropout=False):
+                 unk_penalty=0, retain_dropout=False, sampling=False):
         """Generates translations of a given source sentence.
 
         Args:
@@ -36,7 +36,7 @@ class SequenceGenerator(object):
         self.vocab_size = len(models[0].dst_dict)
         self.beam_size = beam_size
         self.minlen = minlen
-        max_decoder_len = min([m.max_decoder_positions() for m in self.models])
+        max_decoder_len = min(m.max_decoder_positions() for m in self.models)
         max_decoder_len -= 1  # we define maxlen not including the EOS marker
         self.maxlen = max_decoder_len if maxlen is None else min(maxlen, max_decoder_len)
         self.stop_early = stop_early
@@ -44,6 +44,7 @@ class SequenceGenerator(object):
         self.len_penalty = len_penalty
         self.unk_penalty = unk_penalty
         self.retain_dropout = retain_dropout
+        self.sampling = sampling
 
     def cuda(self):
         for model in self.models:
@@ -78,7 +79,7 @@ class SequenceGenerator(object):
                     prefix_tokens=s['target'][:, :prefix_size] if prefix_size > 0 else None,
                 )
             if timer is not None:
-                timer.stop(sum([len(h[0]['tokens']) for h in hypos]))
+                timer.stop(sum(len(h[0]['tokens']) for h in hypos))
             for i, id in enumerate(s['id'].data):
                 src = input['src_tokens'].data[i, :]
                 # remove padding from ref
@@ -255,9 +256,10 @@ class SequenceGenerator(object):
                 probs = probs.unfold(0, 1, beam_size).squeeze(2).contiguous()
                 scores = scores.type_as(probs)
                 scores_buf = scores_buf.type_as(probs)
-            else:
+            elif not self.sampling:
                 # make probs contain cumulative scores for each hypothesis
                 probs.add_(scores[:, step-1].view(-1, 1))
+
             probs[:, self.pad] = -math.inf  # never select pad
             probs[:, self.unk] -= self.unk_penalty  # apply unk penalty
 
@@ -278,6 +280,31 @@ class SequenceGenerator(object):
                     ).expand(-1, cand_size)
                     cand_indices = prefix_tokens[:, step].view(-1, 1).expand(bsz, cand_size).data
                     cand_beams.resize_as_(cand_indices).fill_(0)
+                elif self.sampling:
+                    assert self.pad == 1, 'sampling assumes the first two symbols can be ignored'
+                    exp_probs = probs.exp_().view(-1, self.vocab_size)
+                    if step == 0:
+                        # we exclude the first two vocab items, one of which is pad
+                        torch.multinomial(exp_probs[:, 2:], beam_size, replacement=True, out=cand_indices)
+                        cand_indices.add_(2)
+                    else:
+                        torch.multinomial(exp_probs[:, 2:], 1, replacement=True, out=cand_indices)
+                        cand_indices.add_(2)
+                    torch.gather(exp_probs, dim=1, index=cand_indices, out=cand_scores)
+                    cand_scores.log_()
+                    cand_indices = cand_indices.view(bsz, -1).repeat(1, 2)
+                    cand_scores = cand_scores.view(bsz, -1).repeat(1, 2)
+                    if step == 0:
+                        cand_beams = torch.zeros(bsz, cand_size).type_as(cand_indices)
+                    else:
+                        cand_beams = torch.arange(0, beam_size).repeat(bsz, 2).type_as(cand_indices)
+                        # make scores cumulative
+                        cand_scores.add_(
+                            torch.gather(
+                                scores[:, step-1].view(bsz, beam_size), dim=1,
+                                index=cand_beams,
+                            )
+                        )
                 else:
                     # take the best 2 x beam_size predictions. We'll choose the first
                     # beam_size of these which don't predict eos to continue with.
@@ -411,8 +438,13 @@ class SequenceGenerator(object):
         avg_attn = None
         for model, encoder_out in zip(self.models, encoder_outs):
             with utils.maybe_no_grad():
-                decoder_out, attn = model.decoder(tokens, encoder_out, incremental_states[model])
-            probs = model.get_normalized_probs(decoder_out[:, -1, :], log_probs=False).data
+                if incremental_states[model] is not None:
+                    decoder_out = list(model.decoder(tokens, encoder_out, incremental_states[model]))
+                else:
+                    decoder_out = list(model.decoder(tokens, encoder_out))
+                decoder_out[0] = decoder_out[0][:, -1, :]
+                attn = decoder_out[1]
+            probs = model.get_normalized_probs(decoder_out, log_probs=False).data
             if avg_probs is None:
                 avg_probs = probs
             else:

fairseq/sequence_scorer.py

@@ -63,10 +63,11 @@ class SequenceScorer(object):
                     net_input['src_tokens'],
                     net_input['src_lengths'],
                 )
-                decoder_out, attn = model.decoder(
+                decoder_out = model.decoder(
                     net_input['prev_output_tokens'],
                     encoder_out,
                 )
+                attn = decoder_out[1]
             probs = model.get_normalized_probs(decoder_out, log_probs=False).data
             if avg_probs is None:
                 avg_probs = probs

fairseq/tokenizer.py

@@ -58,10 +58,14 @@ class Tokenizer:
         return {'nseq': nseq, 'nunk': sum(replaced.values()), 'ntok': ntok, 'replaced': len(replaced)}
 
     @staticmethod
-    def tokenize(line, dict, tokenize=tokenize_line, add_if_not_exist=True, consumer=None):
+    def tokenize(line, dict, tokenize=tokenize_line, add_if_not_exist=True,
+                 consumer=None, append_eos=True, reverse_order=False):
         words = tokenize(line)
+        if reverse_order:
+            words = list(reversed(words))
         nwords = len(words)
-        ids = torch.IntTensor(nwords + 1)
+        ids = torch.IntTensor(nwords + 1 if append_eos else nwords)
+
         for i, word in enumerate(words):
             if add_if_not_exist:
                 idx = dict.add_symbol(word)
@@ -70,5 +74,6 @@ class Tokenizer:
             if consumer is not None:
                 consumer(word, idx)
             ids[i] = idx
-        ids[nwords] = dict.eos_index
+        if append_eos:
+            ids[nwords] = dict.eos_index
         return ids