configuration_custom_seq2seq_llm.py

from transformers import PreTrainedModel, PretrainedConfig


class Seq2SeqConfig(PretrainedConfig):
    def __init__(
        self,
        vocab_size=30522,
        hidden_size=768,
        num_encoder_layers=6,
        num_decoder_layers=12,
        num_attention_heads=12,
        num_key_value_heads=4,
        intermediate_size=3072,
        hidden_act="silu",
        hidden_dropout_prob=0.0,
        attention_probs_dropout_prob=0.0,
        max_position_embeddings=512,
        initializer_range=0.02,
        layer_norm_eps=1e-12,
        pad_token_id=0,
        bos_token_id=1,
        eos_token_id=2,
        use_cache=True,
        rotary_emb_dim=0, 
        rotary_emb_base=10000.0,  
        rotary_emb_scale_base=None,  
        rotary_emb_interleaved=False,  
        **kwargs
    ):
        super().__init__(pad_token_id=pad_token_id, bos_token_id=bos_token_id, eos_token_id=eos_token_id, **kwargs)
        self.vocab_size = vocab_size
        self.hidden_size = hidden_size
        self.num_encoder_layers = num_encoder_layers
        self.num_decoder_layers = num_decoder_layers
        self.num_attention_heads = num_attention_heads
        self.num_key_value_heads = num_key_value_heads
        self.hidden_act = hidden_act
        self.intermediate_size = intermediate_size
        self.hidden_dropout_prob = hidden_dropout_prob
        self.attention_probs_dropout_prob = attention_probs_dropout_prob
        self.max_position_embeddings = max_position_embeddings
        self.initializer_range = initializer_range
        self.layer_norm_eps = layer_norm_eps
        self.use_cache = use_cache
        self.rotary_emb_base = rotary_emb_base
        self.rotary_emb_scale_base = rotary_emb_scale_base
        self.rotary_emb_interleaved = rotary_emb_interleaved

        # Calculate head_dim and set rotary_emb_dim
        self.head_dim = self.hidden_size // self.num_attention_heads
        self.rotary_emb_dim = kwargs.get('rotary_emb_dim', self.head_dim // 2)
        
        # Ensure rotary_emb_dim is not larger than head_dim
        if self.rotary_emb_dim > self.head_dim:
            print(f"Warning: rotary_emb_dim ({self.rotary_emb_dim}) is larger than head_dim ({self.head_dim}). Setting rotary_emb_dim to head_dim.")
            self.rotary_emb_dim = self.head_dim