add BERT experiment results (#333)

* add BERT experiment results

* cleanup

* formatting
This commit is contained in:
Sebastian Raschka
2024-08-23 08:40:40 -05:00
committed by GitHub
parent 7cbfe418bf
commit 296a91afb8
8 changed files with 638 additions and 128 deletions

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@@ -18,7 +18,7 @@ For example,
| 5 | gpt2-small (124M) | pretrained | last | all | longest train ex. (120) | 99.62% | 96.64% | 96.67% | 0.69 min | A100 |
| 6 | gpt2-medium (355M) | pretrained | last | last_block | longest train ex. (120) | 87.50% | 91.28% | 84.67% | 0.75 min | A100 |
| 7 | gpt2-large (774M) | pretrained | last | last_block | longest train ex. (120) | 99.52% | 98.66% | 96.67% | 1.50 min | A100 |
| 8 | gpt2-xl (1558M) | pretrained | last | last_block | longest train ex. (120) | 99.81% | 99.33% | 98.33% | 2.83 min | A100 |
| 8 | gpt2-xl (1558M) | pretrained | last | last_block | longest train ex. (120) | 99.81% | 99.81% | 98.33% | 2.83 min | A100 |
| 9 | gpt2-xl (1558M) | pretrained | last | all | longest train ex. (120) | 100.00% | 98.66% | 98.67% | 8.12 min | A100 |
| 10 | gpt2-small (124M) | random | last | all | longest train ex. (120) | 100.00% | 96.64% | 93.67% | 0.69 min | A100 |
| 11 | gpt2-small (124M) | pretrained | last | LoRA | longest train ex. (120) | 100.00% | 97.32% | 96.67% | 0.75 min | A100 |
@@ -35,23 +35,23 @@ For example,
You can use the following code to reproduce the experiments:
- Row 1: `python additional-experiments.py`
- Row 2: `python additional-experiments.py --trainable_token_pos first`
- Row 3: `python additional-experiments.py --trainable_layers last_layer`
- Row 4: `python additional-experiments.py --trainable_layers last_two_blocks`
- Row 5: `python additional-experiments.py --trainable_layers all`
- Row 6: `python additional-experiments.py --model_size "gpt2-medium (355M)"`
- Row 7: `python additional-experiments.py --model_size "gpt2-large (774M)"`
- Row 8: `python additional-experiments.py --model_size "gpt2-xl (1558M)"`
- Row 9: `python additional-experiments.py --model_size "gpt2-xl (1558M)"--trainable_layers all`
- Row 10: `python additional-experiments.py --weights random --trainable_layers all`
- Row 11: `python additional-experiments.py --trainable_layers lora --lora_rank 16 --lora_alpha 16`
- Row 12: `python additional-experiments.py --trainable_layers lora --lora_rank 16 --lora_alpha 8 --model_size "gpt2-xl (1558M)"`
- Row 13: `python additional-experiments.py --context_length "model_context_length"`
- Row 14: `python additional-experiments.py --no_padding --batch_size 1`
- Row 15: `python additional-experiments.py --no_padding --batch_size 1 --accumulation_steps 8`
- Row 16: `python additional-experiments.py --disable_causal_mask`
- Row 17: `python additional-experiments.py --ignore_index 50256`
- Row 1: `python additional_experiments.py`
- Row 2: `python additional_experiments.py --trainable_token_pos first`
- Row 3: `python additional_experiments.py --trainable_layers last_layer`
- Row 4: `python additional_experiments.py --trainable_layers last_two_blocks`
- Row 5: `python additional_experiments.py --trainable_layers all`
- Row 6: `python additional_experiments.py --model_size "gpt2-medium (355M)"`
- Row 7: `python additional_experiments.py --model_size "gpt2-large (774M)"`
- Row 8: `python additional_experiments.py --model_size "gpt2-xl (1558M)"`
- Row 9: `python additional_experiments.py --model_size "gpt2-xl (1558M)"--trainable_layers all`
- Row 10: `python additional_experiments.py --weights random --trainable_layers all`
- Row 11: `python additional_experiments.py --trainable_layers lora --lora_rank 16 --lora_alpha 16`
- Row 12: `python additional_experiments.py --trainable_layers lora --lora_rank 16 --lora_alpha 8 --model_size "gpt2-xl (1558M)"`
- Row 13: `python additional_experiments.py --context_length "model_context_length"`
- Row 14: `python additional_experiments.py --no_padding --batch_size 1`
- Row 15: `python additional_experiments.py --no_padding --batch_size 1 --accumulation_steps 8`
- Row 16: `python additional_experiments.py --disable_causal_mask`
- Row 17: `python additional_experiments.py --ignore_index 50256`
I've kept the LLM and dataset small on purpose, so you can run the training on a regular laptop like a MacBook Air M3 in about 15 minutes (for the default setting) in case you don't have access to a GPU.
@@ -60,7 +60,7 @@ I've kept the LLM and dataset small on purpose, so you can run the training on a
### Interpretation
1. **Training the Last vs. First Output Token Position (Row 1 vs. 2)**: Training the last output token position results in substantially better performance compared to the first. This improvement is expected due to the causal self-attention mask.
2. **Training the Last Transformer Block vs. Last Layer (Row 1 vs. 3)**: Training the entire last transformer block also results in substantially better results than training only the last layer.
2. **Training the Last Transformer Block vs. Last Layer (Row 1 vs. 3)**: Training the entire last transformer block is also results in substantially better results than training only the last layer.
3. **Training the Last vs. Last Two Last Transformer Blocks (Row 1 vs. 4)**: Training the two last transformer blocks instead of only the last block results in a noticeable 3.33% accuracy boost.
4. **Training Last Transformer Block vs All Layers (Row 1 vs. 5)**: Training all layers shows a modest improvement of ~2% over just training the last transformer block, but it requires almost three times longer in terms of training duration. Also, it does not perform as well as training only the last two out of 12 transformer blocks.
5. **Using Larger Pretrained Models (Row 1 vs 6, and Row 1 vs. 7 and 8)**: Employing a 3x larger pretrained model leads to worse results. However, using a 5x larger model improves performance compared to the initial model, as was anticipated. Similarly, the 12x larger model improves the predictive performance even further. (The medium model was perhaps not well pretrained or the particular finetuning configuration works not as well for this model.)

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@@ -17,111 +17,91 @@ The codes are using the 50k movie reviews from IMDb ([dataset source](https://ai
Run the following code to create the `train.csv`, `validation.csv`, and `test.csv` datasets:
```bash
python download-prepare-dataset.py
python download_prepare_dataset.py
```
 
## Step 3: Run Models
The 124M GPT-2 model used in the main chapter, starting for the pretrained weights and only training the last transformer block plus output layers:
The 124M GPT-2 model used in the main chapter, starting with pretrained weights, and finetuning all weights:
```bash
python train-gpt.py
python train_gpt.py --trainable_layers "all" --num_epochs 1
```
```
Ep 1 (Step 000000): Train loss 2.829, Val loss 3.433
Ep 1 (Step 000050): Train loss 1.440, Val loss 1.669
Ep 1 (Step 000100): Train loss 0.879, Val loss 1.037
Ep 1 (Step 000150): Train loss 0.838, Val loss 0.866
Ep 1 (Step 000000): Train loss 3.706, Val loss 3.853
Ep 1 (Step 000050): Train loss 0.682, Val loss 0.706
...
Ep 1 (Step 004300): Train loss 0.174, Val loss 0.202
Ep 1 (Step 004350): Train loss 0.309, Val loss 0.190
Training accuracy: 88.75% | Validation accuracy: 91.25%
Ep 2 (Step 004400): Train loss 0.263, Val loss 0.205
Ep 2 (Step 004450): Train loss 0.226, Val loss 0.188
...
Ep 2 (Step 008650): Train loss 0.189, Val loss 0.171
Ep 2 (Step 008700): Train loss 0.225, Val loss 0.179
Training accuracy: 85.00% | Validation accuracy: 90.62%
Ep 3 (Step 008750): Train loss 0.206, Val loss 0.187
Ep 3 (Step 008800): Train loss 0.198, Val loss 0.172
...
Training accuracy: 96.88% | Validation accuracy: 90.62%
Training completed in 18.62 minutes.
Ep 1 (Step 004300): Train loss 0.199, Val loss 0.285
Ep 1 (Step 004350): Train loss 0.188, Val loss 0.208
Training accuracy: 95.62% | Validation accuracy: 95.00%
Training completed in 9.48 minutes.
Evaluating on the full datasets ...
Training accuracy: 93.66%
Validation accuracy: 90.02%
Test accuracy: 89.96%
Training accuracy: 95.64%
Validation accuracy: 92.32%
Test accuracy: 91.88%
```
<br>
---
<br>
A 340M parameter encoder-style [BERT](https://arxiv.org/abs/1810.04805) model:
```bash
!python train_bert_hf --trainable_layers "all" --num_epochs 1 --model "bert"
```
```
Ep 1 (Step 000000): Train loss 0.848, Val loss 0.775
Ep 1 (Step 000050): Train loss 0.655, Val loss 0.682
...
Ep 1 (Step 004300): Train loss 0.146, Val loss 0.318
Ep 1 (Step 004350): Train loss 0.204, Val loss 0.217
Training accuracy: 92.50% | Validation accuracy: 88.75%
Training completed in 7.65 minutes.
Evaluating on the full datasets ...
Training accuracy: 94.35%
Validation accuracy: 90.74%
Test accuracy: 90.89%
```
<br>
---
<br>
A 66M parameter encoder-style [DistilBERT](https://arxiv.org/abs/1910.01108) model (distilled down from a 340M parameter BERT model), starting for the pretrained weights and only training the last transformer block plus output layers:
```bash
python train-bert-hf.py
!python train_bert_hf.py --trainable_layers "all" --num_epochs 1 --model "distilbert"
```
```
Ep 1 (Step 000000): Train loss 0.693, Val loss 0.697
Ep 1 (Step 000050): Train loss 0.532, Val loss 0.596
Ep 1 (Step 000100): Train loss 0.431, Val loss 0.446
Ep 1 (Step 000000): Train loss 0.693, Val loss 0.688
Ep 1 (Step 000050): Train loss 0.452, Val loss 0.460
...
Ep 1 (Step 004300): Train loss 0.234, Val loss 0.351
Ep 1 (Step 004350): Train loss 0.190, Val loss 0.222
Training accuracy: 88.75% | Validation accuracy: 88.12%
Ep 2 (Step 004400): Train loss 0.258, Val loss 0.270
Ep 2 (Step 004450): Train loss 0.204, Val loss 0.295
...
Ep 2 (Step 008650): Train loss 0.088, Val loss 0.246
Ep 2 (Step 008700): Train loss 0.084, Val loss 0.247
Training accuracy: 98.75% | Validation accuracy: 90.62%
Ep 3 (Step 008750): Train loss 0.067, Val loss 0.209
Ep 3 (Step 008800): Train loss 0.059, Val loss 0.256
...
Ep 3 (Step 013050): Train loss 0.068, Val loss 0.280
Ep 3 (Step 013100): Train loss 0.064, Val loss 0.306
Training accuracy: 99.38% | Validation accuracy: 87.50%
Training completed in 16.70 minutes.
Ep 1 (Step 004300): Train loss 0.179, Val loss 0.272
Ep 1 (Step 004350): Train loss 0.199, Val loss 0.182
Training accuracy: 95.62% | Validation accuracy: 91.25%
Training completed in 4.26 minutes.
Evaluating on the full datasets ...
Training accuracy: 98.87%
Validation accuracy: 90.98%
Test accuracy: 90.81%
Training accuracy: 95.30%
Validation accuracy: 91.12%
Test accuracy: 91.40%
```
---
A 355M parameter encoder-style [RoBERTa](https://arxiv.org/abs/1907.11692) model, starting for the pretrained weights and only training the last transformer block plus output layers:
```bash
python train-bert-hf.py --bert_model roberta
```
---
A scikit-learn Logistic Regression model as a baseline.
```bash
python train-sklearn-logreg.py
```
```
Dummy classifier:
Training Accuracy: 50.01%
Validation Accuracy: 50.14%
Test Accuracy: 49.91%
Logistic regression classifier:
Training Accuracy: 99.80%
Validation Accuracy: 88.60%
Test Accuracy: 88.84%
```

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@@ -16,29 +16,47 @@ from transformers import AutoTokenizer, AutoModelForSequenceClassification
class IMDBDataset(Dataset):
def __init__(self, csv_file, tokenizer, max_length=None, pad_token_id=50256):
def __init__(self, csv_file, tokenizer, max_length=None, pad_token_id=50256, use_attention_mask=False):
self.data = pd.read_csv(csv_file)
self.max_length = max_length if max_length is not None else self._longest_encoded_length(tokenizer)
self.pad_token_id = pad_token_id
self.use_attention_mask = use_attention_mask
# Pre-tokenize texts
# Pre-tokenize texts and create attention masks if required
self.encoded_texts = [
tokenizer.encode(text)[:self.max_length]
tokenizer.encode(text, truncation=True, max_length=self.max_length)
for text in self.data["text"]
]
# Pad sequences to the longest sequence
# Debug
pad_token_id = 0
self.encoded_texts = [
et + [pad_token_id] * (self.max_length - len(et))
for et in self.encoded_texts
]
if self.use_attention_mask:
self.attention_masks = [
self._create_attention_mask(et)
for et in self.encoded_texts
]
else:
self.attention_masks = None
def _create_attention_mask(self, encoded_text):
return [1 if token_id != self.pad_token_id else 0 for token_id in encoded_text]
def __getitem__(self, index):
encoded = self.encoded_texts[index]
label = self.data.iloc[index]["label"]
return torch.tensor(encoded, dtype=torch.long), torch.tensor(label, dtype=torch.long)
if self.use_attention_mask:
attention_mask = self.attention_masks[index]
else:
attention_mask = torch.ones(self.max_length, dtype=torch.long)
return (
torch.tensor(encoded, dtype=torch.long),
torch.tensor(attention_mask, dtype=torch.long),
torch.tensor(label, dtype=torch.long)
)
def __len__(self):
return len(self.data)
@@ -52,10 +70,11 @@ class IMDBDataset(Dataset):
return max_length
def calc_loss_batch(input_batch, target_batch, model, device):
def calc_loss_batch(input_batch, attention_mask_batch, target_batch, model, device):
attention_mask_batch = attention_mask_batch.to(device)
input_batch, target_batch = input_batch.to(device), target_batch.to(device)
# logits = model(input_batch)[:, -1, :] # Logits of last output token
logits = model(input_batch).logits
logits = model(input_batch, attention_mask=attention_mask_batch).logits
loss = torch.nn.functional.cross_entropy(logits, target_batch)
return loss
@@ -69,9 +88,9 @@ def calc_loss_loader(data_loader, model, device, num_batches=None):
# Reduce the number of batches to match the total number of batches in the data loader
# if num_batches exceeds the number of batches in the data loader
num_batches = min(num_batches, len(data_loader))
for i, (input_batch, target_batch) in enumerate(data_loader):
for i, (input_batch, attention_mask_batch, target_batch) in enumerate(data_loader):
if i < num_batches:
loss = calc_loss_batch(input_batch, target_batch, model, device)
loss = calc_loss_batch(input_batch, attention_mask_batch, target_batch, model, device)
total_loss += loss.item()
else:
break
@@ -87,11 +106,12 @@ def calc_accuracy_loader(data_loader, model, device, num_batches=None):
num_batches = len(data_loader)
else:
num_batches = min(num_batches, len(data_loader))
for i, (input_batch, target_batch) in enumerate(data_loader):
for i, (input_batch, attention_mask_batch, target_batch) in enumerate(data_loader):
if i < num_batches:
attention_mask_batch = attention_mask_batch.to(device)
input_batch, target_batch = input_batch.to(device), target_batch.to(device)
# logits = model(input_batch)[:, -1, :] # Logits of last output token
logits = model(input_batch).logits
logits = model(input_batch, attention_mask=attention_mask_batch).logits
predicted_labels = torch.argmax(logits, dim=1)
num_examples += predicted_labels.shape[0]
correct_predictions += (predicted_labels == target_batch).sum().item()
@@ -119,9 +139,9 @@ def train_classifier_simple(model, train_loader, val_loader, optimizer, device,
for epoch in range(num_epochs):
model.train() # Set model to training mode
for input_batch, target_batch in train_loader:
for input_batch, attention_mask_batch, target_batch in train_loader:
optimizer.zero_grad() # Reset loss gradients from previous batch iteration
loss = calc_loss_batch(input_batch, target_batch, model, device)
loss = calc_loss_batch(input_batch, attention_mask_batch, target_batch, model, device)
loss.backward() # Calculate loss gradients
optimizer.step() # Update model weights using loss gradients
examples_seen += input_batch.shape[0] # New: track examples instead of tokens
@@ -159,17 +179,33 @@ if __name__ == "__main__":
parser.add_argument(
"--trainable_layers",
type=str,
default="last_block",
default="all",
help=(
"Which layers to train. Options: 'all', 'last_block', 'last_layer'."
)
)
parser.add_argument(
"--use_attention_mask",
type=str,
default="true",
help=(
"Whether to use a attention mask for padding tokens. Options: 'true', 'false'"
)
)
parser.add_argument(
"--bert_model",
type=str,
default="distilbert",
help=(
"Which layers to train. Options: 'all', 'last_block', 'last_layer'."
"Which model to train. Options: 'distilbert', 'bert'."
)
)
parser.add_argument(
"--num_epochs",
type=int,
default=1,
help=(
"Number of epochs."
)
)
args = parser.parse_args()
@@ -201,19 +237,21 @@ if __name__ == "__main__":
tokenizer = AutoTokenizer.from_pretrained("distilbert-base-uncased")
elif args.bert_model == "roberta":
elif args.bert_model == "bert":
model = AutoModelForSequenceClassification.from_pretrained(
"FacebookAI/roberta-large", num_labels=2
"bert-base-uncased", num_labels=2
)
model.classifier.out_proj = torch.nn.Linear(in_features=1024, out_features=2)
model.classifier = torch.nn.Linear(in_features=768, out_features=2)
if args.trainable_layers == "last_layer":
pass
elif args.trainable_layers == "last_block":
for param in model.classifier.parameters():
param.requires_grad = True
for param in model.roberta.encoder.layer[-1].parameters():
for param in model.bert.pooler.dense.parameters():
param.requires_grad = True
for param in model.bert.encoder.layer[-1].parameters():
param.requires_grad = True
elif args.trainable_layers == "all":
for param in model.parameters():
@@ -221,7 +259,7 @@ if __name__ == "__main__":
else:
raise ValueError("Invalid --trainable_layers argument.")
tokenizer = AutoTokenizer.from_pretrained("FacebookAI/roberta-large")
tokenizer = AutoTokenizer.from_pretrained("bert-base-uncased")
else:
raise ValueError("Selected --bert_model not supported.")
@@ -234,13 +272,36 @@ if __name__ == "__main__":
# Instantiate dataloaders
###############################
pad_token_id = tokenizer.encode(tokenizer.pad_token)
base_path = Path(".")
train_dataset = IMDBDataset(base_path / "train.csv", max_length=256, tokenizer=tokenizer, pad_token_id=pad_token_id)
val_dataset = IMDBDataset(base_path / "validation.csv", max_length=256, tokenizer=tokenizer, pad_token_id=pad_token_id)
test_dataset = IMDBDataset(base_path / "test.csv", max_length=256, tokenizer=tokenizer, pad_token_id=pad_token_id)
if args.use_attention_mask.lower() == "true":
use_attention_mask = True
elif args.use_attention_mask.lower() == "false":
use_attention_mask = False
else:
raise ValueError("Invalid argument for `use_attention_mask`.")
train_dataset = IMDBDataset(
base_path / "train.csv",
max_length=256,
tokenizer=tokenizer,
pad_token_id=tokenizer.pad_token_id,
use_attention_mask=use_attention_mask
)
val_dataset = IMDBDataset(
base_path / "validation.csv",
max_length=256,
tokenizer=tokenizer,
pad_token_id=tokenizer.pad_token_id,
se_attention_mask=use_attention_mask
)
test_dataset = IMDBDataset(
base_path / "test.csv",
max_length=256,
tokenizer=tokenizer,
pad_token_id=tokenizer.pad_token_id,
use_attention_mask=use_attention_mask
)
num_workers = 0
batch_size = 8
@@ -275,10 +336,9 @@ if __name__ == "__main__":
torch.manual_seed(123)
optimizer = torch.optim.AdamW(model.parameters(), lr=5e-5, weight_decay=0.1)
num_epochs = 3
train_losses, val_losses, train_accs, val_accs, examples_seen = train_classifier_simple(
model, train_loader, val_loader, optimizer, device,
num_epochs=num_epochs, eval_freq=50, eval_iter=20,
num_epochs=args.num_epochs, eval_freq=50, eval_iter=20,
max_steps=None
)

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@@ -0,0 +1,463 @@
# Copyright (c) Sebastian Raschka under Apache License 2.0 (see LICENSE.txt).
# Source for "Build a Large Language Model From Scratch"
# - https://www.manning.com/books/build-a-large-language-model-from-scratch
# Code: https://github.com/rasbt/LLMs-from-scratch
import argparse
import os
from pathlib import Path
import time
import urllib
import zipfile
import pandas as pd
import torch
from torch.utils.data import DataLoader
from torch.utils.data import Dataset
from transformers import AutoTokenizer, AutoModelForSequenceClassification
class SpamDataset(Dataset):
def __init__(self, csv_file, tokenizer, max_length=None, pad_token_id=50256, no_padding=False):
self.data = pd.read_csv(csv_file)
self.max_length = max_length if max_length is not None else self._longest_encoded_length(tokenizer)
# Pre-tokenize texts
self.encoded_texts = [
tokenizer.encode(text)[:self.max_length]
for text in self.data["Text"]
]
if not no_padding:
# Pad sequences to the longest sequence
self.encoded_texts = [
et + [pad_token_id] * (self.max_length - len(et))
for et in self.encoded_texts
]
def __getitem__(self, index):
encoded = self.encoded_texts[index]
label = self.data.iloc[index]["Label"]
return torch.tensor(encoded, dtype=torch.long), torch.tensor(label, dtype=torch.long)
def __len__(self):
return len(self.data)
def _longest_encoded_length(self, tokenizer):
max_length = 0
for text in self.data["Text"]:
encoded_length = len(tokenizer.encode(text))
if encoded_length > max_length:
max_length = encoded_length
return max_length
def download_and_unzip(url, zip_path, extract_to, new_file_path):
if new_file_path.exists():
print(f"{new_file_path} already exists. Skipping download and extraction.")
return
# Downloading the file
with urllib.request.urlopen(url) as response:
with open(zip_path, "wb") as out_file:
out_file.write(response.read())
# Unzipping the file
with zipfile.ZipFile(zip_path, "r") as zip_ref:
zip_ref.extractall(extract_to)
# Renaming the file to indicate its format
original_file = Path(extract_to) / "SMSSpamCollection"
os.rename(original_file, new_file_path)
print(f"File downloaded and saved as {new_file_path}")
def random_split(df, train_frac, validation_frac):
# Shuffle the entire DataFrame
df = df.sample(frac=1, random_state=123).reset_index(drop=True)
# Calculate split indices
train_end = int(len(df) * train_frac)
validation_end = train_end + int(len(df) * validation_frac)
# Split the DataFrame
train_df = df[:train_end]
validation_df = df[train_end:validation_end]
test_df = df[validation_end:]
return train_df, validation_df, test_df
def create_dataset_csvs(new_file_path):
df = pd.read_csv(new_file_path, sep="\t", header=None, names=["Label", "Text"])
# Create balanced dataset
n_spam = df[df["Label"] == "spam"].shape[0]
ham_sampled = df[df["Label"] == "ham"].sample(n_spam, random_state=123)
balanced_df = pd.concat([ham_sampled, df[df["Label"] == "spam"]])
balanced_df = balanced_df.sample(frac=1, random_state=123).reset_index(drop=True)
balanced_df["Label"] = balanced_df["Label"].map({"ham": 0, "spam": 1})
# Sample and save csv files
train_df, validation_df, test_df = random_split(balanced_df, 0.7, 0.1)
train_df.to_csv("train.csv", index=None)
validation_df.to_csv("validation.csv", index=None)
test_df.to_csv("test.csv", index=None)
class SPAMDataset(Dataset):
def __init__(self, csv_file, tokenizer, max_length=None, pad_token_id=50256, use_attention_mask=False):
self.data = pd.read_csv(csv_file)
self.max_length = max_length if max_length is not None else self._longest_encoded_length(tokenizer)
self.pad_token_id = pad_token_id
self.use_attention_mask = use_attention_mask
# Pre-tokenize texts and create attention masks if required
self.encoded_texts = [
tokenizer.encode(text, truncation=True, max_length=self.max_length)
for text in self.data["Text"]
]
self.encoded_texts = [
et + [pad_token_id] * (self.max_length - len(et))
for et in self.encoded_texts
]
if self.use_attention_mask:
self.attention_masks = [
self._create_attention_mask(et)
for et in self.encoded_texts
]
else:
self.attention_masks = None
def _create_attention_mask(self, encoded_text):
return [1 if token_id != self.pad_token_id else 0 for token_id in encoded_text]
def __getitem__(self, index):
encoded = self.encoded_texts[index]
label = self.data.iloc[index]["Label"]
if self.use_attention_mask:
attention_mask = self.attention_masks[index]
else:
attention_mask = torch.ones(self.max_length, dtype=torch.long)
return (
torch.tensor(encoded, dtype=torch.long),
torch.tensor(attention_mask, dtype=torch.long),
torch.tensor(label, dtype=torch.long)
)
def __len__(self):
return len(self.data)
def _longest_encoded_length(self, tokenizer):
max_length = 0
for text in self.data["Text"]:
encoded_length = len(tokenizer.encode(text))
if encoded_length > max_length:
max_length = encoded_length
return max_length
def calc_loss_batch(input_batch, attention_mask_batch, target_batch, model, device):
attention_mask_batch = attention_mask_batch.to(device)
input_batch, target_batch = input_batch.to(device), target_batch.to(device)
# logits = model(input_batch)[:, -1, :] # Logits of last output token
logits = model(input_batch, attention_mask=attention_mask_batch).logits
loss = torch.nn.functional.cross_entropy(logits, target_batch)
return loss
# Same as in chapter 5
def calc_loss_loader(data_loader, model, device, num_batches=None):
total_loss = 0.
if num_batches is None:
num_batches = len(data_loader)
else:
# Reduce the number of batches to match the total number of batches in the data loader
# if num_batches exceeds the number of batches in the data loader
num_batches = min(num_batches, len(data_loader))
for i, (input_batch, attention_mask_batch, target_batch) in enumerate(data_loader):
if i < num_batches:
loss = calc_loss_batch(input_batch, attention_mask_batch, target_batch, model, device)
total_loss += loss.item()
else:
break
return total_loss / num_batches
@torch.no_grad() # Disable gradient tracking for efficiency
def calc_accuracy_loader(data_loader, model, device, num_batches=None):
model.eval()
correct_predictions, num_examples = 0, 0
if num_batches is None:
num_batches = len(data_loader)
else:
num_batches = min(num_batches, len(data_loader))
for i, (input_batch, attention_mask_batch, target_batch) in enumerate(data_loader):
if i < num_batches:
attention_mask_batch = attention_mask_batch.to(device)
input_batch, target_batch = input_batch.to(device), target_batch.to(device)
# logits = model(input_batch)[:, -1, :] # Logits of last output token
logits = model(input_batch, attention_mask=attention_mask_batch).logits
predicted_labels = torch.argmax(logits, dim=1)
num_examples += predicted_labels.shape[0]
correct_predictions += (predicted_labels == target_batch).sum().item()
else:
break
return correct_predictions / num_examples
def evaluate_model(model, train_loader, val_loader, device, eval_iter):
model.eval()
with torch.no_grad():
train_loss = calc_loss_loader(train_loader, model, device, num_batches=eval_iter)
val_loss = calc_loss_loader(val_loader, model, device, num_batches=eval_iter)
model.train()
return train_loss, val_loss
def train_classifier_simple(model, train_loader, val_loader, optimizer, device, num_epochs,
eval_freq, eval_iter, max_steps=None):
# Initialize lists to track losses and tokens seen
train_losses, val_losses, train_accs, val_accs = [], [], [], []
examples_seen, global_step = 0, -1
# Main training loop
for epoch in range(num_epochs):
model.train() # Set model to training mode
for input_batch, attention_mask_batch, target_batch in train_loader:
optimizer.zero_grad() # Reset loss gradients from previous batch iteration
loss = calc_loss_batch(input_batch, attention_mask_batch, target_batch, model, device)
loss.backward() # Calculate loss gradients
optimizer.step() # Update model weights using loss gradients
examples_seen += input_batch.shape[0] # New: track examples instead of tokens
global_step += 1
# Optional evaluation step
if global_step % eval_freq == 0:
train_loss, val_loss = evaluate_model(
model, train_loader, val_loader, device, eval_iter)
train_losses.append(train_loss)
val_losses.append(val_loss)
print(f"Ep {epoch+1} (Step {global_step:06d}): "
f"Train loss {train_loss:.3f}, Val loss {val_loss:.3f}")
if max_steps is not None and global_step > max_steps:
break
# New: Calculate accuracy after each epoch
train_accuracy = calc_accuracy_loader(train_loader, model, device, num_batches=eval_iter)
val_accuracy = calc_accuracy_loader(val_loader, model, device, num_batches=eval_iter)
print(f"Training accuracy: {train_accuracy*100:.2f}% | ", end="")
print(f"Validation accuracy: {val_accuracy*100:.2f}%")
train_accs.append(train_accuracy)
val_accs.append(val_accuracy)
if max_steps is not None and global_step > max_steps:
break
return train_losses, val_losses, train_accs, val_accs, examples_seen
if __name__ == "__main__":
parser = argparse.ArgumentParser()
parser.add_argument(
"--trainable_layers",
type=str,
default="all",
help=(
"Which layers to train. Options: 'all', 'last_block', 'last_layer'."
)
)
parser.add_argument(
"--use_attention_mask",
type=str,
default="true",
help=(
"Whether to use a attention mask for padding tokens. Options: 'true', 'false'"
)
)
parser.add_argument(
"--bert_model",
type=str,
default="distilbert",
help=(
"Which model to train. Options: 'distilbert', 'bert'."
)
)
parser.add_argument(
"--num_epochs",
type=int,
default=1,
help=(
"Number of epochs."
)
)
args = parser.parse_args()
###############################
# Load model
###############################
torch.manual_seed(123)
if args.bert_model == "distilbert":
model = AutoModelForSequenceClassification.from_pretrained(
"distilbert-base-uncased", num_labels=2
)
model.out_head = torch.nn.Linear(in_features=768, out_features=2)
if args.trainable_layers == "last_layer":
pass
elif args.trainable_layers == "last_block":
for param in model.pre_classifier.parameters():
param.requires_grad = True
for param in model.distilbert.transformer.layer[-1].parameters():
param.requires_grad = True
elif args.trainable_layers == "all":
for param in model.parameters():
param.requires_grad = True
else:
raise ValueError("Invalid --trainable_layers argument.")
tokenizer = AutoTokenizer.from_pretrained("distilbert-base-uncased")
elif args.bert_model == "bert":
model = AutoModelForSequenceClassification.from_pretrained(
"bert-base-uncased", num_labels=2
)
model.classifier = torch.nn.Linear(in_features=768, out_features=2)
if args.trainable_layers == "last_layer":
pass
elif args.trainable_layers == "last_block":
for param in model.classifier.parameters():
param.requires_grad = True
for param in model.bert.pooler.dense.parameters():
param.requires_grad = True
for param in model.bert.encoder.layer[-1].parameters():
param.requires_grad = True
elif args.trainable_layers == "all":
for param in model.parameters():
param.requires_grad = True
else:
raise ValueError("Invalid --trainable_layers argument.")
tokenizer = AutoTokenizer.from_pretrained("bert-base-uncased")
else:
raise ValueError("Selected --bert_model not supported.")
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
model.to(device)
model.eval()
###############################
# Instantiate dataloaders
###############################
url = "https://archive.ics.uci.edu/static/public/228/sms+spam+collection.zip"
zip_path = "sms_spam_collection.zip"
extract_to = "sms_spam_collection"
new_file_path = Path(extract_to) / "SMSSpamCollection.tsv"
base_path = Path(".")
file_names = ["train.csv", "validation.csv", "test.csv"]
all_exist = all((base_path / file_name).exists() for file_name in file_names)
if not all_exist:
download_and_unzip(url, zip_path, extract_to, new_file_path)
create_dataset_csvs(new_file_path)
if args.use_attention_mask.lower() == "true":
use_attention_mask = True
elif args.use_attention_mask.lower() == "false":
use_attention_mask = False
else:
raise ValueError("Invalid argument for `use_attention_mask`.")
train_dataset = SPAMDataset(
base_path / "train.csv",
max_length=256,
tokenizer=tokenizer,
pad_token_id=tokenizer.pad_token_id,
use_attention_mask=use_attention_mask
)
val_dataset = SPAMDataset(
base_path / "validation.csv",
max_length=256,
tokenizer=tokenizer,
pad_token_id=tokenizer.pad_token_id,
use_attention_mask=use_attention_mask
)
test_dataset = SPAMDataset(
base_path / "test.csv",
max_length=256,
tokenizer=tokenizer,
pad_token_id=tokenizer.pad_token_id,
use_attention_mask=use_attention_mask
)
num_workers = 0
batch_size = 8
train_loader = DataLoader(
dataset=train_dataset,
batch_size=batch_size,
shuffle=True,
num_workers=num_workers,
drop_last=True,
)
val_loader = DataLoader(
dataset=val_dataset,
batch_size=batch_size,
num_workers=num_workers,
drop_last=False,
)
test_loader = DataLoader(
dataset=test_dataset,
batch_size=batch_size,
num_workers=num_workers,
drop_last=False,
)
###############################
# Train model
###############################
start_time = time.time()
torch.manual_seed(123)
optimizer = torch.optim.AdamW(model.parameters(), lr=5e-5, weight_decay=0.1)
train_losses, val_losses, train_accs, val_accs, examples_seen = train_classifier_simple(
model, train_loader, val_loader, optimizer, device,
num_epochs=args.num_epochs, eval_freq=50, eval_iter=20,
max_steps=None
)
end_time = time.time()
execution_time_minutes = (end_time - start_time) / 60
print(f"Training completed in {execution_time_minutes:.2f} minutes.")
###############################
# Evaluate model
###############################
print("\nEvaluating on the full datasets ...\n")
train_accuracy = calc_accuracy_loader(train_loader, model, device)
val_accuracy = calc_accuracy_loader(val_loader, model, device)
test_accuracy = calc_accuracy_loader(test_loader, model, device)
print(f"Training accuracy: {train_accuracy*100:.2f}%")
print(f"Validation accuracy: {val_accuracy*100:.2f}%")
print(f"Test accuracy: {test_accuracy*100:.2f}%")

View File

@@ -227,6 +227,14 @@ if __name__ == "__main__":
"Options: 'longest_training_example', 'model_context_length' or integer value."
)
)
parser.add_argument(
"--num_epochs",
type=int,
default=1,
help=(
"Number of epochs."
)
)
args = parser.parse_args()
@@ -340,10 +348,9 @@ if __name__ == "__main__":
torch.manual_seed(123)
optimizer = torch.optim.AdamW(model.parameters(), lr=5e-5, weight_decay=0.1)
num_epochs = 3
train_losses, val_losses, train_accs, val_accs, examples_seen = train_classifier_simple(
model, train_loader, val_loader, optimizer, device,
num_epochs=num_epochs, eval_freq=50, eval_iter=20,
num_epochs=args.num_epochs, eval_freq=50, eval_iter=20,
max_steps=None, trainable_token=args.trainable_token
)