fairseq/tests/test_roberta.py
Liang Tan 1575f30dd0 Add ffn prune to fairseq
Summary:
Support FFN prune for Fairseq. For example, user can apply pruning on top of Roberta base model by specify the argument "--ffn-blocks-to-remove 1024". Also, user needs to provide a ckpt which is already pruned so that the pruned ckpt can be loaded correctly.
The idea of prune can be summarized as
Fine tune model (e.g. roberta encoder) on a certain datasets with regularization
After the model is trained. User could use _get_fc_rank and _prune_fc_layer functions to get the top X blocks with most importance in each transformer layer. Then user uses the rank to prune a new roberta encoder and save the pruned ckpt manually.
User will fine tune the the new roberta encoder via the ckpt saved above

Reviewed By: dianaml0

Differential Revision: D33525055

fbshipit-source-id: 5087140ee891d6ec9266726e3a477947c233412c
2022-01-14 16:26:59 -08:00

345 lines
11 KiB
Python

# Copyright (c) Facebook, Inc. and its affiliates.
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
import functools
import unittest
from typing import Any, Dict, Sequence
import fairseq
import fairseq.options
import fairseq.tasks
import torch
from tests.utils import dummy_dictionary
VOCAB_SIZE = 100
@fairseq.tasks.register_task("fake_task")
class FakeTask(fairseq.tasks.LegacyFairseqTask):
def __init__(self, args):
super().__init__(args)
self.dictionary = dummy_dictionary(VOCAB_SIZE - 4)
assert len(self.dictionary) == VOCAB_SIZE
@property
def source_dictionary(self):
return self.dictionary
@property
def target_dictionary(self):
return self.dictionary
@functools.lru_cache()
def get_toy_model(
device: str,
architecture: str = "roberta_enc_dec",
**extra_args: Any,
):
assert device in ("gpu", "cpu")
kwargs = {
"arch": architecture,
# Use characteristics dimensions
"encoder_layers": 3,
"encoder_embed_dim": 12,
"encoder_ffn_embed_dim": 14,
"encoder_attention_heads": 4,
"decoder_layers": 3,
"decoder_embed_dim": 12,
"decoder_ffn_embed_dim": 14,
"decoder_attention_heads": 4,
# Disable dropout so we have comparable tests.
"dropout": 0,
"attention_dropout": 0,
"activation_dropout": 0,
"encoder_layerdrop": 0,
# required args
"tokens_per_sample": 256,
"data": "/tmp/test_roberta",
}
kwargs.update(extra_args)
fake_task = FakeTask(kwargs)
args = fairseq.options.get_args(
task="online_backtranslation",
mono_langs="en,ro",
valid_lang_pairs="en-ro",
**kwargs,
)
torch.manual_seed(0)
model = fake_task.build_model(args)
if device == "gpu":
model.cuda()
return fake_task, model
def mk_sample(
lang: str, device: str, tok: Sequence[int] = None, batch_size: int = 2
) -> Dict[str, Any]:
assert device in ("gpu", "cpu")
if not tok:
if lang == "en":
tok = [10, 11, 12, 13, 14, 15, 2]
else:
tok = [20, 21, 22, 23, 24, 25, 26, 27, 2]
batch = torch.stack([torch.tensor(tok, dtype=torch.long)] * batch_size)
if device == "gpu":
batch = batch.cuda()
sample = {
"net_input": {
"src_tokens": batch,
"prev_output_tokens": batch,
"src_lengths": torch.tensor(
[len(tok)] * batch_size, dtype=torch.long, device=batch.device
),
},
"target": batch[:, 1:],
}
return sample
def cpu_gpu(fn):
def helper(self):
fn(self, "cpu")
if torch.cuda.is_available():
fn(self, "gpu")
return helper
def architectures(fn):
def helper(self):
for arch in ["roberta_enc_dec", "transformer"]:
fn(self, arch)
return helper
class RobertaTest(unittest.TestCase):
def assertTensorEqual(self, t1, t2, delta: float = 1e-6):
self.assertEqual(t1.size(), t2.size(), "size mismatch")
if delta == 0.0:
self.assertEqual(t1.ne(t2).long().sum(), 0)
else:
self.assertEqual(((t2 - t1).abs() > delta).long().sum(), 0)
def assertSharing(self, model, link_groups: Sequence[Sequence[str]]):
ids = {}
for group in link_groups:
group_ids = {name: id(params(model, name)) for name in group}
shared_id = group_ids[group[0]]
self.assertEqual(group_ids, {name: shared_id for name in group})
self.assertNotIn(shared_id, ids)
ids[shared_id] = group
def test_roberta_shared_params(self):
_, roberta = get_toy_model("cpu", architecture="roberta")
self.assertSharing(
roberta,
[
[
"encoder.sentence_encoder.embed_tokens.weight",
"encoder.lm_head.weight",
]
],
)
_, roberta = get_toy_model(
"cpu", architecture="roberta", untie_weights_roberta=True
)
self.assertSharing(
roberta,
[
["encoder.sentence_encoder.embed_tokens.weight"],
["encoder.lm_head.weight"],
],
)
def test_roberta_enc_dec_shared_params(self):
# 3 distinct embeddings
_, enc_dec = get_toy_model("cpu", architecture="roberta_enc_dec")
self.assertSharing(
enc_dec,
[
["encoder.embed_tokens.weight"],
["decoder.embed_tokens.weight"],
["decoder.output_projection.weight"],
],
)
# 2 distinct embeddings, one for encoder, one for decoder
_, enc_dec = get_toy_model(
"cpu", architecture="roberta_enc_dec", share_decoder_input_output_embed=True
)
self.assertSharing(
enc_dec,
[
["encoder.embed_tokens.weight"],
[
"decoder.embed_tokens.weight",
"decoder.output_projection.weight",
],
],
)
# shared embeddings
_, enc_dec = get_toy_model(
"cpu", architecture="roberta_enc_dec", share_all_embeddings=True
)
self.assertSharing(
enc_dec,
[
[
"encoder.embed_tokens.weight",
"decoder.embed_tokens.weight",
"decoder.output_projection.weight",
]
],
)
def test_roberta_max_positions_is_correctly_set(self):
device = "cpu"
task, model = get_toy_model(device)
max_pos = model.max_decoder_positions()
self.assertEqual(max_pos, 256)
self.assertEqual(max_pos, model.decoder.max_positions())
self.assertEqual(max_pos, model.encoder.max_positions())
self.assertEqual(max_pos, model.encoder.embed_positions.max_positions)
sentence = [31 for _ in range(max_pos)]
sample = mk_sample("en", device, sentence, batch_size=1)
self.assertEqual(list(sample["net_input"]["src_lengths"]), [max_pos])
self.assertEqual(len(sample["net_input"]["src_tokens"][0]), max_pos)
x, _ = model.forward(**sample["net_input"])
self.assertEqual(x.shape, (1, max_pos, VOCAB_SIZE))
@cpu_gpu
def test_roberta_forward_backward(self, device: str):
_, model = get_toy_model(device)
sample = mk_sample("en", device)
en_tokens = sample["net_input"]["src_tokens"]
(bs, l) = en_tokens.shape
# Forward
logits, _ = model(**sample["net_input"])
self.assertEqual(logits.shape, (bs, l, VOCAB_SIZE))
# Backward
loss = logits.sum()
loss.backward()
@cpu_gpu
def test_roberta_forward_backward_bs1(self, device: str):
_, model = get_toy_model(device)
sample = mk_sample("en", device, batch_size=1)
o, _ = model.forward(**sample["net_input"])
loss = o.sum()
sample2 = mk_sample("ro", device, batch_size=1)
o, _ = model.forward(**sample2["net_input"])
loss += o.sum()
loss.backward()
@cpu_gpu
def test_roberta_batching(self, device: str):
"""
Checks that the batch of size 2 give twice the same results than the batch of size 1.
"""
_, model = get_toy_model(device)
sample = mk_sample("en", device, batch_size=1)
slen = sample["net_input"]["src_lengths"][0]
sample2 = mk_sample("en", device, batch_size=2)
with torch.no_grad():
z = model.encoder.forward(
sample["net_input"]["src_tokens"], sample["net_input"]["src_lengths"]
)
z = z["encoder_out"][-1]
logits, _ = model.forward(**sample["net_input"])
z2 = model.encoder.forward(
sample2["net_input"]["src_tokens"], sample["net_input"]["src_lengths"]
)
z2 = z2["encoder_out"][-1]
logits2, _ = model.forward(**sample2["net_input"])
self.assertEqual(z.shape, (slen, 1, 12))
self.assertEqual(z2.shape, (slen, 2, 12))
self.assertTensorEqual(logits2[0], logits2[1])
self.assertTensorEqual(logits[0], logits2[0])
@cpu_gpu
def test_roberta_incremental_decoder(self, device: str):
"""
Checks that incremental decoding yields the same result than non incremental one.
"""
task, model = get_toy_model(device)
en_sample = mk_sample("en", device)
en_tokens = en_sample["net_input"]["src_tokens"]
ro_sample = mk_sample("ro", device)
ro_tokens = ro_sample["net_input"]["src_tokens"]
en_enc = model.encoder.forward(
en_tokens, src_lengths=en_sample["net_input"]["src_lengths"]
)
(bs, tgt_len) = ro_tokens.shape
# Decode without incremental state
ro_dec, _ = model.decoder.forward(ro_tokens, encoder_out=en_enc)
self.assertEqual(ro_dec.shape, (bs, tgt_len, VOCAB_SIZE))
self.assertTensorEqual(ro_dec[0], ro_dec[1])
# Decode with incremental state
inc_state = {}
ro_dec_inc = []
for i in range(tgt_len):
ro, _ = model.decoder.forward(
ro_tokens[:, : i + 1], encoder_out=en_enc, incremental_state=inc_state
)
self.assertEqual(ro.shape, (bs, 1, VOCAB_SIZE))
ro_dec_inc.append(ro)
for i in range(tgt_len):
# Intra-batch
self.assertTensorEqual(ro_dec_inc[i][0], ro_dec_inc[i][1])
# Incremental vs non-incremental
self.assertTensorEqual(ro_dec_inc[i][:, 0], ro_dec[:, i])
@cpu_gpu
def test_regularize_for_adaprune_in_roberta(self, device: str):
_, model = get_toy_model(
device=device,
architecture="roberta_base",
mha_reg_scale_factor=0.000375,
ffn_reg_scale_factor=0.000375,
)
sample = mk_sample("en", device, batch_size=1)
task_loss, _ = model.forward(**sample["net_input"])
head_loss = model._get_adaptive_head_loss()
ffn_loss = model._get_adaptive_ffn_loss()
loss = task_loss.sum() + head_loss + ffn_loss
loss.backward()
@cpu_gpu
def test_ffn_prune_for_adaprune_in_roberta(self, device: str):
_, model = get_toy_model(
device=device,
architecture="roberta_base",
)
sample = mk_sample("en", device, batch_size=1)
for layer in model.encoder.sentence_encoder.layers:
fc1_original_size = layer.fc1.out_features
remove_index = layer._get_fc_rank(remove_num=2)
layer._prune_fc_layer(remove_index=remove_index)
self.assertEqual(layer.fc1.out_features, fc1_original_size - 2)
task_loss, _ = model.forward(**sample["net_input"])
def params(model, name):
if "." not in name:
return getattr(model, name)
prefix, name = name.split(".", 1)
return params(getattr(model, prefix), name)