# Using BART models encoder and decoder

**URL:** <https://discuss.huggingface.co/t/using-bart-models-encoder-and-decoder/26486>\
**Category:** Models\
**Created:** [November 22, 2022, 6:00am UTC](https://discuss.huggingface.co/t/using-bart-models-encoder-and-decoder/26486 "2022-11-22T06:00:37Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![bk073](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@bk073](https://discuss.huggingface.co/u/bk073)\
**Post date:** [November 22, 2022, 6:00am UTC](https://discuss.huggingface.co/t/using-bart-models-encoder-and-decoder/26486/1 "2022-11-22T06:00:37Z")

</div>

I wanted to use encoder and decoder of BART model separately, is it possible?

Here is what I have done, but it is not working on decoder saying **Module [ModuleList] is missing the required “forward” function**.

```
class Encoder(torch.nn.Module):
  def __init__ (self):
    super(Encoder, self). __init__ ()
    model = BartForConditionalGeneration.from_pretrained('facebook/bart-large-cnn')
    self.enc = torch.nn.Sequential(model.get_encoder().base_model)

  def forward(self, inputs):
    embedding_code = self.enc(inputs['input_ids'])
    return embedding_code

class Decoder(torch.nn.Module):
  def __init__ (self):
    super(Decoder, self). __init__ ()
    model = BartForConditionalGeneration.from_pretrained('facebook/bart-large-cnn')
    self.dec = torch.nn.Sequential(model.get_decoder().layers)
  
  def forward(self, x):
    x = self.dec(x)
    return x

tokenizer = BertTokenizer.from_pretrained(PRE_TRAINED_MODEL_NAME)
inputs = tokenizer([ARTICLE_TO_SUMMARIZE], return_tensors='pt')

code = Encoder()(inputs['input_ids'])  
Decoder()(code.last_hidden_state)

```

Any thought on this implementation

---

<div class="post-metadata">

**Author:** ![bk073](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@bk073](https://discuss.huggingface.co/u/bk073)\
**Post date:** [November 22, 2022, 2:27pm UTC](https://discuss.huggingface.co/t/using-bart-models-encoder-and-decoder/26486/2 "2022-11-22T14:27:24Z")

</div>

@sgugger @patrickvonplaten any suggestions?