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64 lines
2.4 KiB
64 lines
2.4 KiB
import torch
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import torch.nn as nn
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from transformers import GPT2Config, GPT2LMHeadModel
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class GPTLMModel(nn.Module):
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def __init__(self, hidden_size=768, num_layers=12, num_attention_heads=12, max_seq_len=1024, vocab_size=50257):
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super().__init__()
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self.model = GPT2LMHeadModel(
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GPT2Config(
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n_embd=hidden_size,
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n_layer=num_layers,
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n_head=num_attention_heads,
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n_positions=max_seq_len,
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n_ctx=max_seq_len,
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vocab_size=vocab_size,
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)
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)
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def forward(self, input_ids, attention_mask):
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# Only return lm_logits
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return self.model(input_ids=input_ids, attention_mask=attention_mask, use_cache=True)[0]
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class GPTLMLoss(nn.Module):
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def __init__(self):
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super().__init__()
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self.loss_fn = nn.CrossEntropyLoss()
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def forward(self, logits, labels):
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shift_logits = logits[..., :-1, :].contiguous()
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shift_labels = labels[..., 1:].contiguous()
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# Flatten the tokens
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return self.loss_fn(shift_logits.view(-1, shift_logits.size(-1)), shift_labels.view(-1))
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def get_gpt2_components(model_type: str, batch_size: int):
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vocab_size = 1024
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seq_len = 8
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def gpt2_model_builder():
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if model_type == "gpt2_medium":
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return GPTLMModel(hidden_size=1024, num_layers=24, num_attention_heads=16)
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elif model_type == "gpt2_xl":
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return GPTLMModel(hidden_size=1600, num_layers=48, num_attention_heads=32)
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elif model_type == "gpt2_10b":
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return GPTLMModel(hidden_size=4096, num_layers=50, num_attention_heads=16)
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elif model_type == "gpt2_14b":
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return GPTLMModel(hidden_size=4096, num_layers=70, num_attention_heads=16)
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elif model_type == "gpt2_20b":
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return GPTLMModel(hidden_size=8192, num_layers=25, num_attention_heads=16)
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elif model_type == "gpt2_24b":
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return GPTLMModel(hidden_size=8192, num_layers=30, num_attention_heads=16)
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else:
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raise TypeError(f"model_builder {model_type}")
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def gpt2_data_gen(device="cuda"):
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input_ids = torch.randint(0, vocab_size, (batch_size, seq_len), device=device)
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attention_mask = torch.ones_like(input_ids, device=device)
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kwargs = dict(input_ids=input_ids, attention_mask=attention_mask)
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return kwargs
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return gpt2_model_builder, gpt2_data_gen
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