chat.py

import torch
from model import TransformerModel
from tokenizer import SimpleTokenizer

# Load tokenizer
tokenizer = SimpleTokenizer("vocab_path")

# Use same values from train.py
vocab_size = len(tokenizer.char_to_idx)
embed_size = 64
num_heads = 2
hidden_dim = 128
num_layers = 2
max_len = 32

device = torch.device("cuda" if torch.cuda.is_available() else "cpu")

# Create the same model and load weights
model = TransformerModel(vocab_size, embed_size, num_heads, hidden_dim, num_layers, max_len).to(device)
model.load_state_dict(torch.load("model.pth", map_location=device))
model.eval()

# Chat loop
while True:
    user_input = input("You: ")
    if user_input.lower() in ["quit", "exit"]:
        break

    input_ids = tokenizer.encode(user_input)
    input_tensor = torch.tensor([input_ids], dtype=torch.long).to(device)

    with torch.no_grad():
        output = model(input_tensor)[0]  # shape: [seq_len, vocab_size]
        prediction = torch.argmax(output, dim=-1).squeeze().tolist()

    response = tokenizer.decode(prediction)
    print("AI:", response)