def forward(self, input_ids):
        """
        we have 2 embeddings, with different indices - one pretrained self.weight and another
        self.additional_embedding.weight that is being trained.

        in order to make a lookup of the input ids, we:
        1. find out the indices of the entries belonging to the 2nd embedding
        2. extract those values while subtracting the size of the first embedding (num_embeddings), since the 2nd
           embedding starts from 0 and not num_embeddings
        3. perform the 2nd embedding lookup
        4. now we handle the 1st embedding, we overwrite indices belonging to the 2nd embedding with a padding index
        5. perform the 1st embedding lookup
        6. now we overwrite the values in the 1st embedding lookup with the values of the 2nd embedding lookup

        note: for the 1st embedding lookup we could have looked up only the low indices and not do the padding, but
        then we have to create a new tensor and populate it with 2 tensors that are spread out across various indices -
        i.e. not a simple concat - I haven't benchmarked the complex case if it's any faster, given that seqlens are
        usually relatively short it's probably not faster or if faster not by much - but might be a good idea to
        measure.

        """
        if self.num_additional_embeddings == 0:
            return F.embedding(input_ids, self.weight)

        # Clone so that we don't modify the original input_ids later on
        input_ids = input_ids.clone()
        additional_vocab_indices = torch.where(input_ids >= self.num_embeddings)
        input_ids_additional_vocab = input_ids[additional_vocab_indices]
        additional_embeddings = self.additional_embedding(input_ids_additional_vocab - self.num_embeddings)

        # for successful lookup replace input_ids with 0, the results of these will be discarded anyway
        input_ids[additional_vocab_indices] = 0
        full_vector = F.embedding(input_ids, self.weight)

        # overwrite the records with high indices
        full_vector[additional_vocab_indices] = additional_embeddings

        return full_vector

        we have 2 embeddings, with different indices - one pretrained self.weight and another
        self.additional_embedding.weight that is being trained.

        in order to make a lookup of the input ids, we:
        1. find out the indices of the entries belonging to the 2nd embedding
        2. extract those values while subtracting the size of the first embedding (num_embeddings), since the 2nd
           embedding starts from 0 and not num_embeddings
        3. perform the 2nd embedding lookup
        4. now we handle the 1st embedding, we overwrite indices belonging to the 2nd embedding with a padding index
        5. perform the 1st embedding lookup
        6. now we overwrite the values in the 1st embedding lookup with the values of the 2nd embedding lookup

        note: for the 1st embedding lookup we could have looked up only the low indices and not do the padding, but
        then we have to create a new tensor and populate it with 2 tensors that are spread out across various indices -
        i.e. not a simple concat - I haven't benchmarked the complex case if it's any faster, given that seqlens are
        usually relatively short it's probably not faster or if faster not by much - but might be a good idea to
        measure.

        
dpkd/transformers/src/transformers/models/idefics/modeling_idefics.py