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"""A HuggingFace-style model configuration.""" |
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import warnings |
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from typing import Any, Dict, Optional, Union |
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from transformers import PretrainedConfig |
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from .attention import check_alibi_support, is_flash_v2_installed |
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from .blocks import attn_config_defaults |
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from .fc import FC_CLASS_REGISTRY |
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from .norm import LPLayerNorm |
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from .ffn import FFN_CLASS_REGISTRY |
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ffn_config_defaults: Dict = {'ffn_type': 'mptmlp'} |
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init_config_defaults: Dict = {'name': 'kaiming_normal_', 'fan_mode': 'fan_in', 'init_nonlinearity': 'relu', 'init_div_is_residual': True, 'emb_init_std': None, 'emb_init_uniform_lim': None, 'init_std': None, 'init_gain': 0.0} |
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class MPTConfig(PretrainedConfig): |
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model_type = 'mpt' |
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def __init__(self, d_model: int=2048, n_heads: int=16, n_layers: int=24, expansion_ratio: Union[int, float]=4, max_seq_len: int=2048, vocab_size: int=50368, resid_pdrop: float=0.0, emb_pdrop: float=0.0, learned_pos_emb: bool=True, attn_config: Dict=attn_config_defaults, ffn_config: Dict=ffn_config_defaults, init_device: str='cpu', logit_scale: Optional[Union[float, str]]=None, no_bias: bool=False, embedding_fraction: float=1.0, norm_type: str='low_precision_layernorm', use_cache: bool=False, init_config: Dict=init_config_defaults, fc_type: str='torch', tie_word_embeddings: bool=True, use_pad_tok_in_ffn: bool=True, **kwargs: Any): |
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"""The MPT configuration class. |
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Args: |
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d_model (int): The size of the embedding dimension of the model. |
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n_heads (int): The number of attention heads. |
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n_layers (int): The number of layers in the model. |
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expansion_ratio (Union[int, float]): The ratio of the up/down scale in the ffn. |
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max_seq_len (int): The maximum sequence length of the model. |
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vocab_size (int): The size of the vocabulary. |
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resid_pdrop (float): The dropout probability applied to the attention output before combining with residual. |
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emb_pdrop (float): The dropout probability for the embedding layer. |
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learned_pos_emb (bool): Whether to use learned positional embeddings |
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attn_config (Dict): A dictionary used to configure the model's attention module: |
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attn_type (str): type of attention to use. Options: multihead_attention, multiquery_attention, grouped_query_attention |
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attn_pdrop (float): The dropout probability for the attention layers. |
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attn_impl (str): The attention implementation to use. One of 'torch' or 'flash'. |
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qk_ln (bool): Whether to apply layer normalization to the queries and keys in the attention layer. |
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qk_gn (bool): Whether to apply group normalization to the queries and keys in the attention layer. |
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clip_qkv (Optional[float]): If not None, clip the queries, keys, and values in the attention layer to |
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this value. |
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softmax_scale (Optional[float]): If not None, scale the softmax in the attention layer by this value. If None, |
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use the default scale of ``1/sqrt(d_keys)``. |
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attn_uses_sequence_id (Optional[bool]): Whether to restrict attention to tokens that have the same sequence_id. |
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When the model is in `train` mode, this requires passing an extra `sequence_id` argument which indicates |
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which sub-sequence each token belongs to. |
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Defaults to ``False`` meaning any provided `sequence_id` will be ignored. |
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sliding_window_size (int): Window size for sliding window local attention. Defaults to -1, which means no sliding window. Query at position i will only attend to keys between [i + seqlen_k - seqlen_q - window_size, i + seqlen_k - seqlen_q + window_size] inclusive. Only works for flash attention v2.3.0 or higher. |
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alibi (bool): Whether to use the alibi bias instead of position embeddings. |
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alibi_bias_max (int): The maximum value of the alibi bias. |
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rope (bool): Whether to use rotary positional embeddings. |
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rope_theta (int): The base frequency for rope. |
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rope_impl (str): The implementation of rope to use. One of 'hf' (to use the implementation from https://github.com/huggingface/transformers/blob/main/src/transformers/models/llama/modeling_llama.py) or 'dail' (to use the implementation from https://github.com/Dao-AILab/flash-attention/blob/main/flash_attn/layers/rotary.py). |
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rope_dail_config (Dict): The configuration for the dail implementation of rope. |
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type (str): The type of rotary position embedding to use. Options: 'original' (for https://arxiv.org/pdf/2104.09864.pdf), 'xpos' (for https://arxiv.org/pdf/2212.10554.pdf). |
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pos_idx_in_fp32 (bool): If True, the position indices [0, ..., seqlen - 1] are in fp32, otherwise they might be in lower precision. A consequence could be, for example, that bf16 rounds position 1995 to 2000, which leads to them having the same positional embedding. |
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xpos_scale_base (float): The scale base for XPos (if using XPos). |
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rope_hf_config (Dict): A dictionary used to configure rope's scaling behavior (when scaling beyond the training length). |
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type (str): Can be one of 'no_scaling', 'linear', or 'dynamic'. 'no_scaling' uses the default implementation for rotary embeddings, 'linear' uses linear scaling as proposed by the Reddit user /u/kaiokendev, and 'dynamic' uses Dynamic NTK scaling as proposed by the Reddit users /u/bloc97 and /u/emozilla. |
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factor (float): Scaling factor to use if using 'linear' or 'dynamic' as rope_scaling.type. |
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kv_n_heads (Optional[int]): For grouped_query_attention only, allow user to specify number of kv heads. |
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ffn_config (Dict): A dictionary used to configure the model's ffn module: |
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ffn_type (str): type of ffn to use. Options: mptmlp, mptglu, te_ln_mlp |
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init_device (str): The device to use for parameter initialization. |
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logit_scale (Optional[Union[float, str]]): If not None, scale the logits by this value. |
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no_bias (bool): Whether to use bias in all layers. |
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embedding_fraction (float): The fraction to scale the gradients of the embedding layer by. |
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norm_type (str): choose type of norm to use |
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use_cache (bool): Whether or not the model should return the last key/values attentions |
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init_config (Dict): A dictionary used to configure the model initialization: |
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init_config.name: The parameter initialization scheme to use. Options: 'default_', 'baseline_', |
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'kaiming_uniform_', 'kaiming_normal_', 'neox_init_', 'small_init_', 'xavier_uniform_', or |
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'xavier_normal_'. These mimic the parameter initialization methods in PyTorch. |
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init_div_is_residual (Union[int, float, str, bool]): Value to divide initial weights by if ``module._is_residual`` is True. |
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emb_init_std (Optional[float]): The standard deviation of the normal distribution used to initialize the embedding layer. |
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emb_init_uniform_lim (Optional[Union[Tuple[float, float], float]]): The lower and upper limits of the uniform distribution |
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used to initialize the embedding layer. Mutually exclusive with ``emb_init_std``. |
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init_std (float): The standard deviation of the normal distribution used to initialize the model, |
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if using the baseline_ parameter initialization scheme. |
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init_gain (float): The gain to use for parameter initialization with kaiming or xavier initialization schemes. |
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fan_mode (str): The fan mode to use for parameter initialization with kaiming initialization schemes. |
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init_nonlinearity (str): The nonlinearity to use for parameter initialization with kaiming initialization schemes. |
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--- |
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See llmfoundry.models.utils.param_init_fns.py for info on other param init config options |
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fc_type (str): choose fc layer implementation. Options: torch and te. te layers support fp8 when using H100 GPUs. |
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tie_word_embeddings (bool): Whether to tie the input embedding and output layers. |
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use_pad_tok_in_ffn (bool): Whether to forward the pad token in the feedforward networks. |
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""" |
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self.d_model = d_model |
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self.n_heads = n_heads |
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self.n_layers = n_layers |
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self.expansion_ratio = expansion_ratio |
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self.max_seq_len = max_seq_len |
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self.vocab_size = vocab_size |
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self.resid_pdrop = resid_pdrop |
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self.emb_pdrop = emb_pdrop |
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self.learned_pos_emb = learned_pos_emb |
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self.attn_config = attn_config |
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self.ffn_config = ffn_config |
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self.init_device = init_device |
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self.logit_scale = logit_scale |
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self.no_bias = no_bias |
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self.embedding_fraction = embedding_fraction |
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self.norm_type = norm_type |
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self.use_cache = use_cache |
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self.init_config = init_config |
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self.fc_type = fc_type |
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self.use_pad_tok_in_ffn = use_pad_tok_in_ffn |
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if 'name' in kwargs: |
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del kwargs['name'] |
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if 'loss_fn' in kwargs: |
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del kwargs['loss_fn'] |
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if self.attn_config.get('alibi', False) or self.attn_config.get('rope', False): |
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self.learned_pos_emb = False |
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warnings.warn(f'alibi or rope is turned on, setting `learned_pos_emb` to `False.`') |
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super().__init__(tie_word_embeddings=tie_word_embeddings, **kwargs) |
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self._validate_config() |
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def _set_config_defaults(self, config: Dict[str, Any], config_defaults: Dict[str, Any]) -> Dict[str, Any]: |
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for k, v in config_defaults.items(): |
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if k not in config: |
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config[k] = v |
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elif isinstance(v, dict): |
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config[k] = self._set_config_defaults(config[k] if config[k] is not None else {}, v) |
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return config |
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def _validate_config(self) -> None: |
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self.attn_config = self._set_config_defaults(self.attn_config, attn_config_defaults) |
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self.ffn_config = self._set_config_defaults(self.ffn_config, ffn_config_defaults) |
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self.init_config = self._set_config_defaults(self.init_config, init_config_defaults) |
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if self.d_model % self.n_heads != 0: |
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raise ValueError('d_model must be divisible by n_heads') |
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if any((prob < 0 or prob > 1 for prob in [self.attn_config['attn_pdrop'], self.resid_pdrop, self.emb_pdrop])): |
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raise ValueError("self.attn_config['attn_pdrop'], resid_pdrop, emb_pdrop are probabilities and must be between 0 and 1") |
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if self.attn_config['attn_impl'] not in ['torch', 'flash']: |
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raise ValueError(f"Unknown attn_impl={self.attn_config['attn_impl']}") |
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if self.attn_config['alibi'] and (not check_alibi_support(self.attn_config['attn_impl'])): |
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raise NotImplementedError('alibi only implemented with torch and flash (v2.4.2 or higher) attention.') |
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if self.attn_config['attn_uses_sequence_id'] and (not (self.attn_config['attn_impl'] == 'torch' or (self.attn_config['attn_impl'] == 'flash' and is_flash_v2_installed(v2_version='v2.1.2')))): |
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raise NotImplementedError('attn_uses_sequence_id only implemented with torch and flash (v2.1.2 or higher) attention.') |
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if self.attn_config['rope'] and self.attn_config['rope_impl'] not in ['dail', 'hf']: |
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raise ValueError('If rope is being used then rope_impl should be either "dail", or "hf".') |
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if self.attn_config['rope'] and self.attn_config['rope_impl'] == 'hf' and (self.attn_config['rope_hf_config']['type'] not in ['no_scaling', 'linear', 'dynamic']): |
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raise ValueError('If using hf implementation of rope, the type should be one of "no_scaling", "linear" or "dynamic".') |
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if self.attn_config['rope'] and self.attn_config['rope_impl'] == 'dail': |
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if self.attn_config['rope_dail_config']['type'] not in ['original', 'xpos']: |
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raise ValueError('If using the dail implementation of rope, the type should be one of "original" or "xpos".') |
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if not is_flash_v2_installed(v2_version='2.0.1'): |
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raise ImportError('If using the dail implementation of rope, the flash_attn library v2.0.1 or higher must be installed. Please check the instructions at https://github.com/mosaicml/llm-foundry/blob/main/TUTORIAL.md#what-kinds-of-positional-embeddings-does-llm-foundry-support') |
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if self.attn_config['sliding_window_size'] != -1 and (not (self.attn_config['attn_impl'] == 'flash' and is_flash_v2_installed(v2_version='v2.3.0'))): |
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raise NotImplementedError('sliding window only implemented with flash attention v2.3.0 or higher.') |
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if self.embedding_fraction > 1 or self.embedding_fraction <= 0: |
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raise ValueError('model.embedding_fraction must be between 0 (exclusive) and 1 (inclusive)!') |
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if isinstance(self.logit_scale, str) and self.logit_scale != 'inv_sqrt_d_model': |
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raise ValueError(f"self.logit_scale={self.logit_scale!r} is not recognized as an option; use numeric value or 'inv_sqrt_d_model'.") |
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if self.init_config.get('name', None) is None: |
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raise ValueError(f"self.init_config={self.init_config!r} 'name' needs to be set.") |
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if not (self.learned_pos_emb or self.attn_config['alibi'] or self.attn_config['rope']): |
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warnings.warn(f'Positional information not being provided to the model using either learned_pos_emb or alibi or rope.') |
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if self.fc_type == 'te' or self.ffn_config['ffn_type'] == 'te_ln_mlp': |
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try: |
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import transformer_engine.pytorch as te |
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del te |
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except: |
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raise ImportError('TransformerEngine import fail. `fc_type: te` requires TransformerEngine be installed. ' + 'The required version of transformer_engine also requires FlashAttention v1.0.6 is installed:\n' + 'pip install flash-attn==1.0.6 --no-build-isolation \n' + 'pip install git+https://github.com/NVIDIA/TransformerEngine.git@144e4888b2cdd60bd52e706d5b7a79cb9c1a7156') |
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if self.ffn_config['ffn_type'] == 'mptgeglu': |
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raise ValueError('API CHANGE: `ffn_type=="mptgeglu"` changed to `ffn_type=="mptglu"`. ' + 'See [#829](https://github.com/mosaicml/llm-foundry/pull/829) for details.') |
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elif self.ffn_config['ffn_type'] in ['mptmlp', 'mptglu']: |
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self.ffn_config['fc_type'] = self.fc_type |
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elif self.ffn_config['ffn_type'] == 'te_ln_mlp': |
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self.ffn_config['bias'] = not self.no_bias |
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if 'ffn_act_fn' in self.ffn_config.keys(): |
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raise ValueError(f'Transformer Engine block does not support custom activation functions.') |
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if not self.use_pad_tok_in_ffn: |
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try: |
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from flash_attn.bert_padding import unpad_input, pad_input |
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except: |
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raise ImportError('In order to set `use_pad_tok_in_ffn=False`, please install flash-attn==1.0.9 or flash-attn==2.3.6') |