import torch
import torch.nn as nn
import torch.optim as optim
from torch.nn.utils.rnn import pack_padded_sequence, pad_packed_sequence

class SimpleModel(nn.Module):
    # ... (same as before)

# Sample input sequences with varying lengths
input_sequences = [
    [0, 1, 2],
    [3, 4, 5, 6],
    [7, 8, 9, 10, 11]
]

# Convert input sequences to PyTorch tensors
padded_input = nn.utils.rnn.pad_sequence([torch.LongTensor(seq) for seq in input_sequences], batch_first=True)

# Create the model
model = SimpleModel(input_size, hidden_size, output_size)
criterion = nn.CrossEntropyLoss()
optimizer = optim.Adam(model.parameters(), lr=0.001)

# Training loop
optimizer.zero_grad()
loss = 0

for i in range(len(input_sequences)):
    input_sequence = padded_input[i]
    target_sequence = input_sequence[1:]  # Predict the next letter

    # Initialize hidden state
    hidden = (torch.zeros(1, len(input_sequence), hidden_size), torch.zeros(1, len(input_sequence), hidden_size))

    # Forward pass
    packed_input = pack_padded_sequence(input_sequence.unsqueeze(0), [len(input_sequence)], batch_first=True)
    packed_output, hidden = model(packed_input, hidden)
    output, _ = pad_packed_sequence(packed_output, batch_first=True)

    # Compute loss
    loss += criterion(output.view(-1, output_size), target_sequence)

loss.backward()
optimizer.step()

print("Loss:", loss.item())












23,24,18,9,22,10,4,1,6,8,21,25,3,19,7,20,13,12,16

7,6,2,16,26,18,11,25,1,3,9,4,23,10,17,8,16,22,21,19

16,20,2,15,9,18,25,6,17,7,8,5,13,22,3,23,26,4,10,1

24,10,9,19,7,5,2,15,8,13,20,23,4,12,6,11,22,26,3,16

7,12,2,18,14,21,16,5,10,4,11,3,25,8,22,1,15,24,6,13

2,26,8,9,7,4,18,5,13,19,25,1,24,15,11,6,16,22,14,21

16,22,5,21,25,17,10,13,15,3,24,14,20,9,19,6,12,1,11

25,7,2,26,21,16,3,18,14,8,10,17,9,23,13,20,5,11,22,6

13,12,8,7,15,10,9,1,24,2,14,11,10,25,26,5,22,17,21,18

22,26,5,24,14,3,25,23,1,21,13,11,6,16,18,17,2,8,15,8

1,11,6,23,5,8,10,24,13,26,2,14,9,4,19,17,18,16,25,21

9,23,26,22,8,11,10,19,1,16,24,15,4,3,6,17,2,12,5,13

21,9,24,13,20,22,8,25,2,23,16,7,1,11,15,14,3,4,18,12

15,25,22,21,9,8,18,6,7,3,24,26,19,2,20,14,12,1,10,16

15,1,4,21,23,7,8,18,16,25,14,2,22,20,12,3,5,6,11,24

3,14,16,6,8,1,15,11,12,5,18,26,22,21,10,7,17,9,8,18

7,17,6,16,10,2,21,12,22,3,8,13,11,22,1,20,9,12,19,15

2,9,3,4,21,26,7,18,22,5,15,8,11,25,10,16,13,6,1,19

8,14,22,16,2,23,10,5,9,15,21,13,1,4,6,18,11,12,3,10

5,8,18,12,17,16,26,2,23,13,21,22,19,14,16,4,1,15,25,24

24,5,18,22,3,9,15,21,16,25,7,17,14,6,8,11,19,13,2,23

13,2,14,8,15,21,9,5,19,18,22,6,10,16,7,12,4,3,25,11

2,22,4,23,18,17,16,15,11,20,14,9,21,3,13,10