def test_expand_reverse_index(self):
reverse_index = [1, 0, 2]
n_best = 1
reverse_index_1best = expand_reverse_index(reverse_index, n_best)
self.assertEqual(reverse_index_1best, [1, 0, 2])
n_best = 2
reverse_index_2best = expand_reverse_index(reverse_index, n_best)
self.assertEqual(reverse_index_2best, [2, 3, 0, 1, 4, 5])
n_best = 3
reverse_index_3best = expand_reverse_index(reverse_index, n_best)
self.assertEqual(reverse_index_3best, [3, 4, 5, 0, 1, 2, 6, 7, 8])
def validate_on_data(model: Model, data: Dataset,
batch_size: int,
use_cuda: bool, max_output_length: int,
level: str, eval_metric: Optional[str],
n_gpu: int,
batch_class: Batch = Batch,
compute_loss: bool = False,
beam_size: int = 1, beam_alpha: int = -1,
batch_type: str = "sentence",
postprocess: bool = True,
bpe_type: str = "subword-nmt",
sacrebleu: dict = None,
n_best: int = 1) \
-> (float, float, float, List[str], List[List[str]], List[str],
List[str], List[List[str]], List[np.array]):
"""
Generate translations for the given data.
If `compute_loss` is True and references are given,
also compute the loss.
:param model: model module
:param data: dataset for validation
:param batch_size: validation batch size
:param batch_class: class type of batch
:param use_cuda: if True, use CUDA
:param max_output_length: maximum length for generated hypotheses
:param level: segmentation level, one of "char", "bpe", "word"
:param eval_metric: evaluation metric, e.g. "bleu"
:param n_gpu: number of GPUs
:param compute_loss: whether to computes a scalar loss
for given inputs and targets
:param beam_size: beam size for validation.
If <2 then greedy decoding (default).
:param beam_alpha: beam search alpha for length penalty,
disabled if set to -1 (default).
:param batch_type: validation batch type (sentence or token)
:param postprocess: if True, remove BPE segmentation from translations
:param bpe_type: bpe type, one of {"subword-nmt", "sentencepiece"}
:param sacrebleu: sacrebleu options
:param n_best: Amount of candidates to return
:return:
- current_valid_score: current validation score [eval_metric],
- valid_loss: validation loss,
- valid_ppl:, validation perplexity,
- valid_sources: validation sources,
- valid_sources_raw: raw validation sources (before post-processing),
- valid_references: validation references,
- valid_hypotheses: validation_hypotheses,
- decoded_valid: raw validation hypotheses (before post-processing),
- valid_attention_scores: attention scores for validation hypotheses
"""
assert batch_size >= n_gpu, "batch_size must be bigger than n_gpu."
if sacrebleu is None: # assign default value
sacrebleu = {"remove_whitespace": True, "tokenize": "13a"}
if batch_size > 1000 and batch_type == "sentence":
logger.warning(
"WARNING: Are you sure you meant to work on huge batches like "
"this? 'batch_size' is > 1000 for sentence-batching. "
"Consider decreasing it or switching to"
" 'eval_batch_type: token'.")
valid_iter = make_data_iter(dataset=data,
batch_size=batch_size,
batch_type=batch_type,
shuffle=False,
train=False)
valid_sources_raw = data.src
pad_index = model.src_vocab.stoi[PAD_TOKEN]
# disable dropout
model.eval()
# don't track gradients during validation
with torch.no_grad():
all_outputs = []
valid_attention_scores = []
total_loss = 0
total_ntokens = 0
total_nseqs = 0
for valid_batch in iter(valid_iter):
# run as during training to get validation loss (e.g. xent)
batch = batch_class(valid_batch, pad_index, use_cuda=use_cuda)
# sort batch now by src length and keep track of order
reverse_index = batch.sort_by_src_length()
sort_reverse_index = expand_reverse_index(reverse_index, n_best)
# run as during training with teacher forcing
if compute_loss and batch.trg is not None:
batch_loss, _, _, _ = model(return_type="loss", **vars(batch))
if n_gpu > 1:
batch_loss = batch_loss.mean() # average on multi-gpu
total_loss += batch_loss
total_ntokens += batch.ntokens
total_nseqs += batch.nseqs
# run as during inference to produce translations
output, attention_scores = run_batch(
model=model,
batch=batch,
beam_size=beam_size,
beam_alpha=beam_alpha,
max_output_length=max_output_length,
n_best=n_best)
# sort outputs back to original order
all_outputs.extend(output[sort_reverse_index])
valid_attention_scores.extend(
attention_scores[sort_reverse_index]
if attention_scores is not None else [])
assert len(all_outputs) == len(data) * n_best
if compute_loss and total_ntokens > 0:
# total validation loss
valid_loss = total_loss
# exponent of token-level negative log prob
valid_ppl = torch.exp(total_loss / total_ntokens)
else:
valid_loss = -1
valid_ppl = -1
# decode back to symbols
decoded_valid = model.trg_vocab.arrays_to_sentences(arrays=all_outputs,
cut_at_eos=True)
# evaluate with metric on full dataset
join_char = " " if level in ["word", "bpe"] else ""
valid_sources = [join_char.join(s) for s in data.src]
valid_references = [join_char.join(t) for t in data.trg]
valid_hypotheses = [join_char.join(t) for t in decoded_valid]
# post-process
if level == "bpe" and postprocess:
valid_sources = [
bpe_postprocess(s, bpe_type=bpe_type) for s in valid_sources
]
valid_references = [
bpe_postprocess(v, bpe_type=bpe_type) for v in valid_references
]
valid_hypotheses = [
bpe_postprocess(v, bpe_type=bpe_type) for v in valid_hypotheses
]
# if references are given, evaluate against them
if valid_references:
assert len(valid_hypotheses) == len(valid_references)
current_valid_score = 0
if eval_metric.lower() == 'bleu':
# this version does not use any tokenization
current_valid_score = bleu(valid_hypotheses,
valid_references,
tokenize=sacrebleu["tokenize"])
elif eval_metric.lower() == 'chrf':
current_valid_score = chrf(
valid_hypotheses,
valid_references,
remove_whitespace=sacrebleu["remove_whitespace"])
elif eval_metric.lower() == 'token_accuracy':
current_valid_score = token_accuracy( # supply List[List[str]]
list(decoded_valid), list(data.trg))
elif eval_metric.lower() == 'sequence_accuracy':
current_valid_score = sequence_accuracy(
valid_hypotheses, valid_references)
else:
current_valid_score = -1
return current_valid_score, valid_loss, valid_ppl, valid_sources, \
valid_sources_raw, valid_references, valid_hypotheses, \
decoded_valid, valid_attention_scores