107 lines
3.9 KiB
Python
107 lines
3.9 KiB
Python
import torch
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import torch.nn as nn
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import torch.nn.functional as F
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class MiniGPT(nn.Module):
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def __init__(self, vocab_size, embed_dim=128, n_heads=4, n_layers=2, max_len=128):
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super().__init__()
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self.token_embed = nn.Embedding(vocab_size, embed_dim)
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self.pos_embed = nn.Embedding(max_len, embed_dim)
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self.blocks = nn.ModuleList([
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nn.TransformerEncoderLayer(d_model=embed_dim, nhead=n_heads, batch_first=True)
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for _ in range(n_layers)
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])
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self.ln_f = nn.LayerNorm(embed_dim)
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self.head = nn.Linear(embed_dim, vocab_size)
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def forward(self, x):
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seq_len = x.size(1)
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pos = torch.arange(0, seq_len, device=x.device).unsqueeze(0)
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x = self.token_embed(x) + self.pos_embed(pos)
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for block in self.blocks:
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x = block(x)
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x = self.ln_f(x)
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return self.head(x)
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class RubyTrainer:
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def __init__(self, tokenizer, embed_dim=128, n_heads=4, n_layers=2, max_len=128):
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self.tokenizer = tokenizer
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self.device = "cuda" if torch.cuda.is_available() else "cpu"
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self.embed_dim = embed_dim
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self.n_heads = n_heads
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self.n_layers = n_layers
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self.max_len = max_len
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self.model = None
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self.optimizer = None
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self.criterion = torch.nn.CrossEntropyLoss()
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self.rebuild_model_if_needed()
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def rebuild_model_if_needed(self):
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vocab_size = len(self.tokenizer.vocab)
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if self.model is None or self.model.token_embed.num_embeddings != vocab_size:
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print("[MODEL] Initializing/Reinitializing model with vocab size:", vocab_size)
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self.model = MiniGPT(
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vocab_size,
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self.embed_dim,
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self.n_heads,
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self.n_layers,
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self.max_len
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).to(self.device)
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self.optimizer = torch.optim.Adam(self.model.parameters(), lr=0.001)
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def train_on_tokens_from_text(self, text: str):
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tokens = self.tokenizer.tokenize(text)
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if not tokens:
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return
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# Wrap with <START> and <END>
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tokens = [self.tokenizer.vocab["<START>"]] + tokens + [self.tokenizer.vocab["<END>"]]
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if len(tokens) < 2:
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print("[TRAIN] Skipped (not enough tokens)")
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return
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self.rebuild_model_if_needed()
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self.model.train()
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x = torch.tensor(tokens[:-1], dtype=torch.long, device=self.device).unsqueeze(0)
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y = torch.tensor(tokens[1:], dtype=torch.long, device=self.device).unsqueeze(0)
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out = self.model(x)
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loss = self.criterion(out.view(-1, out.size(-1)), y.view(-1))
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loss.backward()
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self.optimizer.step()
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self.optimizer.zero_grad()
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print(f"[TRAIN] Tokens: {tokens} | Loss: {loss.item():.4f}")
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def generate_reply(self, max_tokens=15, temperature=1.0, top_k=5):
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self.model.eval()
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input_ids = torch.tensor([[self.tokenizer.vocab["<START>"]]], dtype=torch.long, device=self.device)
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for _ in range(max_tokens):
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with torch.no_grad():
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out = self.model(input_ids)
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logits = out[:, -1, :] / temperature
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if top_k > 0:
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top_k_logits, top_k_indices = torch.topk(logits, top_k)
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probs = F.softmax(top_k_logits, dim=-1)
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next_token = top_k_indices[0][torch.multinomial(probs, 1)]
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else:
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probs = F.softmax(logits, dim=-1)
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next_token = torch.multinomial(probs, 1)[0]
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# ⬇️ Fix here: reshape next_token to (1, 1)
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next_token = next_token.view(1, 1)
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input_ids = torch.cat([input_ids, next_token], dim=1)
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if next_token.item() == self.tokenizer.vocab["<END>"]:
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break
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token_ids = input_ids.squeeze(0).tolist()[1:] # skip <START>
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return self.tokenizer.detokenize(token_ids)
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