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"""A simple, flexible implementation of a GPT model. |
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Inspired by https://github.com/karpathy/minGPT/blob/master/mingpt/model.py |
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""" |
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from __future__ import annotations |
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import math |
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import warnings |
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from typing import Any, Dict, List, Mapping, MutableMapping, Optional, Tuple, Union |
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import torch |
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import torch.nn as nn |
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import torch.nn.functional as F |
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from .attention import is_flash_v1_installed, is_flash_v2_installed |
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if is_flash_v2_installed(): |
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try: |
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from flash_attn import bert_padding |
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from flash_attn.layers.rotary import RotaryEmbedding as DAILRotaryEmbedding |
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except Exception as e: |
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raise e |
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if is_flash_v1_installed(): |
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try: |
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from flash_attn import bert_padding |
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except Exception as e: |
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raise e |
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from transformers import PreTrainedModel, PreTrainedTokenizerBase |
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from transformers.modeling_outputs import BaseModelOutputWithPast, CausalLMOutputWithPast |
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from transformers.models.llama.modeling_llama import LlamaDynamicNTKScalingRotaryEmbedding as HFDynamicNTKScalingRotaryEmbedding |
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from transformers.models.llama.modeling_llama import LlamaLinearScalingRotaryEmbedding as HFLinearScalingRotaryEmbedding |
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from transformers.models.llama.modeling_llama import LlamaRotaryEmbedding as HFRotaryEmbedding |
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from .attention import ATTN_CLASS_REGISTRY, attn_bias_shape, build_attn_bias, gen_slopes |
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from .blocks import MPTBlock |
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from .custom_embedding import SharedEmbedding |
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from .fc import FC_CLASS_REGISTRY as FC_CLASS_REGISTRY |
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from .ffn import FFN_CLASS_REGISTRY as FFN_CLASS_REGISTRY |
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from .ffn import MPTMLP as MPTMLP |
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from .ffn import build_ffn as build_ffn |
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from .norm import NORM_CLASS_REGISTRY |
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from .configuration_mpt import MPTConfig |
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from .adapt_tokenizer import AutoTokenizerForMOD, adapt_tokenizer_for_denoising |
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from .hf_prefixlm_converter import add_bidirectional_mask_if_missing, convert_hf_causal_lm_to_prefix_lm |
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from .meta_init_context import init_empty_weights |
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from .param_init_fns import generic_param_init_fn_, MODEL_INIT_REGISTRY |
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try: |
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from .flash_attn_triton import flash_attn_func as flash_attn_func |
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except: |
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pass |
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import logging |
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log = logging.getLogger(__name__) |
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|
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def gen_rotary_embedding(rope_head_dim: int, rope_impl: str, rope_theta: int, rope_dail_config: dict, rope_hf_config: dict, max_seq_len: int): |
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if rope_impl == 'dail': |
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return DAILRotaryEmbedding(dim=rope_head_dim, base=rope_theta, interleaved=False, scale_base=rope_dail_config['xpos_scale_base'] if rope_dail_config['type'] == 'xpos' else None, pos_idx_in_fp32=rope_dail_config['pos_idx_in_fp32'], device='cpu') |
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elif rope_impl == 'hf': |
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if rope_hf_config['type'] == 'no_scaling': |
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return HFRotaryEmbedding(rope_head_dim, max_position_embeddings=max_seq_len, base=rope_theta, device='cpu') |
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elif rope_hf_config['type'] == 'linear': |
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return HFLinearScalingRotaryEmbedding(rope_head_dim, max_position_embeddings=max_seq_len, base=rope_theta, scaling_factor=rope_hf_config['factor'], device='cpu') |
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elif rope_hf_config['type'] == 'dynamic': |
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return HFDynamicNTKScalingRotaryEmbedding(rope_head_dim, max_position_embeddings=max_seq_len, base=rope_theta, scaling_factor=rope_hf_config['factor'], device='cpu') |
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raise ValueError('rope_impl needs to be either dail or hf') |
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|
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def gen_attention_mask_in_length(sequence_id: Union[None, torch.Tensor], S: int, attn_uses_sequence_id: bool, attn_impl: str, attention_mask: Union[torch.Tensor, None]): |
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"""Generates the attention mask used for sequence masking in FA v2. |
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Only supports sequence id based sparse attention for no attention masking or attention masking with right padding. |
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In case of left padding: |
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1. Training with left padding is not supported in MPT (see https://github.com/mosaicml/llm-foundry/blob/1eecd4cb8e734499f77f6a35f657b8b20c0adfcb/llmfoundry/models/mpt/modeling_mpt.py#L407). |
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2. For generation with left padding, we only have a single sequence id per sample, so we don't need sequence id based sparse attention. |
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|
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Args: |
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sequence_id (Union[None, torch.Tensor]): Tensor containing the sequence id for each token. Shape (batch_size, seq_len). |
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S (int): Sequence length |
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attn_uses_sequence_id (bool): Whether the attention uses sequence id based masking. |
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attn_impl (str): Attention implementation. This function is only creates attention_mask_in_length for flash attention. |
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attention_mask (Union[torch.Tensor, None]): Attention mask tensor of shape (batch_size, seq_len) |
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Returns: |
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attention_mask_in_length: (batch, seqlen), int, a nonzero number (e.g., 1, 2, 3, etc.) means length of concatenated sequence in b-th batch, and 0 means none. For example, if batch = 3 and seqlen = 6, the attention_mask_in_length is: |
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``` |
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[ |
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[2, 3, 0, 0, 0, 0], |
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[3, 2, 0, 0, 0, 0], |
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[6, 0, 0, 0, 0, 0] |
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] |
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``` |
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, which refers to the 3D-attention mask: |
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``` |
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[ |
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[ |
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[1, 0, 0, 0, 0, 0], |
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[1, 1, 0, 0, 0, 0], |
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[0, 0, 1, 0, 0, 0], |
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[0, 0, 1, 1, 0, 0], |
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[0, 0, 1, 1, 1, 0], |
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[0, 0, 0, 0, 0, 1] |
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], |
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[ |
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[1, 0, 0, 0, 0, 0], |
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[1, 1, 0, 0, 0, 0], |
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[1, 1, 1, 0, 0, 0], |
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[0, 0, 0, 1, 0, 0], |
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[0, 0, 0, 1, 1, 0], |
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[0, 0, 0, 0, 0, 1] |
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], |
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[ |
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[1, 0, 0, 0, 0, 0], |
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[1, 1, 0, 0, 0, 0], |
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[1, 1, 1, 0, 0, 0], |
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[1, 1, 1, 1, 0, 0], |
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[1, 1, 1, 1, 1, 0], |
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[1, 1, 1, 1, 1, 1] |
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] |
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] |
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```. |
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(The description above is taken verbatim from https://github.com/Dao-AILab/flash-attention/blob/9356a1c0389660d7e231ff3163c1ac17d9e3824a/flash_attn/bert_padding.py#L125 .) |
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""" |
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attention_mask_in_length = None |
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if sequence_id is not None and attn_uses_sequence_id and (attn_impl == 'flash'): |
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if attention_mask is not None and attention_mask[:, 0].sum() != attention_mask.shape[0]: |
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raise NotImplementedError('Left padding is not supported with flash attention when attn_uses_sequence_id is set to True.') |
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if S != sequence_id.shape[-1]: |
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raise ValueError(f'Sequence length ({S}) does not match length of sequences in sequence_id ({sequence_id.shape[-1]}).') |
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if attention_mask is not None: |
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sequence_id = sequence_id.masked_fill(~attention_mask, 0) |
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attention_mask_in_length = torch.nn.functional.one_hot(sequence_id) |
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if attention_mask is not None: |
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attention_mask_in_length = attention_mask_in_length.masked_fill(~attention_mask.unsqueeze(-1), 0) |
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attention_mask_in_length = attention_mask_in_length.sum(dim=1) |
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attention_mask_in_length = torch.nn.functional.pad(attention_mask_in_length, (0, S - attention_mask_in_length.shape[-1]), mode='constant', value=0) |
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return attention_mask_in_length |
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|
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def gen_flash_attn_padding_info(bsz: int, S: int, past_key_len: int, device: torch.device, attention_mask_in_length: Optional[torch.Tensor]=None, attention_mask: Optional[torch.Tensor]=None): |
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flash_attn_padding_info = {} |
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if attention_mask_in_length is None: |
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key_padding_mask = attention_mask |
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if key_padding_mask is None: |
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key_padding_mask = torch.ones((bsz, past_key_len + S), dtype=torch.bool, device=device) |
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query_padding_mask = key_padding_mask[:, -S:] |
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unpadding_function = bert_padding.unpad_input |
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else: |
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key_padding_mask = attention_mask_in_length |
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query_padding_mask = attention_mask_in_length |
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unpadding_function = bert_padding.unpad_input_for_concatenated_sequences |
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(_, indices_q, cu_seqlens_q, max_seqlen_q) = unpadding_function(torch.empty(bsz, S, 1, device=device), query_padding_mask) |
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(_, indices_k, cu_seqlens_k, max_seqlen_k) = unpadding_function(torch.empty(bsz, past_key_len + S, 1, device=device), key_padding_mask) |
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(_, indices_v, _, _) = unpadding_function(torch.empty(bsz, past_key_len + S, 1, device=device), key_padding_mask) |
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flash_attn_padding_info['indices_q'] = indices_q |
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flash_attn_padding_info['indices_k'] = indices_k |
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flash_attn_padding_info['indices_v'] = indices_v |
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flash_attn_padding_info['cu_seqlens_q'] = cu_seqlens_q |
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flash_attn_padding_info['cu_seqlens_k'] = cu_seqlens_k |
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flash_attn_padding_info['max_seqlen_q'] = max_seqlen_q |
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flash_attn_padding_info['max_seqlen_k'] = max_seqlen_k |
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return flash_attn_padding_info |
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|
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def apply_sequence_id(attn_bias: torch.Tensor, sequence_id: torch.LongTensor, max_seq_len: int) -> torch.Tensor: |
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seq_len = sequence_id.shape[-1] |
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if seq_len > max_seq_len: |
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raise ValueError(f'sequence_id sequence length cannot exceed max_seq_len={max_seq_len}') |
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attn_bias = attn_bias[..., :seq_len, :seq_len] |
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cannot_attend = torch.logical_not(torch.eq(sequence_id.view(-1, seq_len, 1), sequence_id.view(-1, 1, seq_len))).unsqueeze(1) |
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min_val = torch.finfo(attn_bias.dtype).min |
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attn_bias = attn_bias.masked_fill(cannot_attend, min_val) |
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return attn_bias |
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|
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class MPTPreTrainedModel(PreTrainedModel): |
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config_class = MPTConfig |
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base_model_prefix = 'model' |
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_no_split_modules = ['MPTBlock'] |
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def _fsdp_wrap_fn(self: Union[MPTModel, MPTForCausalLM], module: nn.Module) -> bool: |
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return isinstance(module, MPTBlock) |
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class MPTModel(MPTPreTrainedModel): |
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def __init__(self, config: MPTConfig): |
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config._validate_config() |
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super().__init__(config) |
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self.attn_impl = config.attn_config['attn_impl'] |
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self.prefix_lm = config.attn_config['prefix_lm'] |
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self.attn_uses_sequence_id = config.attn_config['attn_uses_sequence_id'] |
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self.alibi = config.attn_config['alibi'] |
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self.alibi_bias_max = config.attn_config['alibi_bias_max'] |
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self.learned_pos_emb = config.learned_pos_emb |
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if config.init_device == 'mixed': |
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if dist.get_local_rank() == 0: |
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config.init_device = 'cpu' |
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else: |
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config.init_device = 'meta' |
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if config.norm_type.lower() not in NORM_CLASS_REGISTRY.keys(): |
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norm_options = ' | '.join(NORM_CLASS_REGISTRY.keys()) |
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raise NotImplementedError(f'Requested norm type ({config.norm_type}) is not implemented within this repo (Options: {norm_options}).') |
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norm_class = NORM_CLASS_REGISTRY[config.norm_type.lower()] |
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self.embedding_fraction = config.embedding_fraction |
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self.wte = SharedEmbedding(config.vocab_size, config.d_model, device=config.init_device) |
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if self.learned_pos_emb: |
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self.wpe = torch.nn.Embedding(config.max_seq_len, config.d_model, device=config.init_device) |
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self.emb_drop = nn.Dropout(config.emb_pdrop) |
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self.blocks = nn.ModuleList([MPTBlock(device=config.init_device, **config.to_dict()) for _ in range(config.n_layers)]) |
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self.norm_f = norm_class(config.d_model, device=config.init_device) |
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self.rope = config.attn_config['rope'] |
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self.rope_impl = None |
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if self.rope: |
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self.rope_impl = config.attn_config['rope_impl'] |
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self.rotary_embedding = gen_rotary_embedding(rope_head_dim=config.d_model // config.n_heads, rope_impl=self.rope_impl, rope_theta=config.attn_config['rope_theta'], rope_dail_config=config.attn_config['rope_dail_config'], rope_hf_config=config.attn_config['rope_hf_config'], max_seq_len=self.config.max_seq_len) |
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if config.init_device != 'meta': |
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log.info(f'We recommend using config.init_device="meta" with Composer + FSDP for faster initialization.') |
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self.apply(self.param_init_fn) |
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self.is_causal = not self.prefix_lm |
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self._attn_bias_initialized = False |
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self.attn_bias = None |
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self.attn_bias_shape = attn_bias_shape(self.attn_impl, config.n_heads, config.max_seq_len, self.alibi, prefix_lm=self.prefix_lm, causal=self.is_causal, use_sequence_id=self.attn_uses_sequence_id) |
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if config.no_bias: |
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for module in self.modules(): |
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if hasattr(module, 'bias') and isinstance(module.bias, nn.Parameter): |
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log.info(f'Removing bias from module={module!r}.') |
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module.register_parameter('bias', None) |
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if hasattr(module, 'use_bias'): |
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log.info(f'Setting use_bias=False for module={module!r}.') |
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module.use_bias = False |
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log.debug(self) |
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log.debug(f"Using {self.config.init_config['name']} initialization.") |
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|
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def get_input_embeddings(self) -> Union[SharedEmbedding, nn.Embedding]: |
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return self.wte |
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|
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def set_input_embeddings(self, value: Union[SharedEmbedding, nn.Embedding]) -> None: |
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self.wte = value |
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|
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@torch.no_grad() |
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def _attn_bias(self, device: torch.device, dtype: torch.dtype, attention_mask: Optional[torch.ByteTensor]=None, prefix_mask: Optional[torch.ByteTensor]=None, sequence_id: Optional[torch.LongTensor]=None) -> Tuple[Optional[torch.Tensor], Optional[torch.ByteTensor]]: |
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if not self._attn_bias_initialized: |
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if self.attn_bias_shape: |
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self.attn_bias = torch.zeros(self.attn_bias_shape, device=device, dtype=dtype) |
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self.attn_bias = build_attn_bias(self.attn_impl, self.attn_bias, self.config.n_heads, self.config.max_seq_len, causal=self.is_causal, alibi=self.alibi, alibi_bias_max=self.alibi_bias_max) |
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self._attn_bias_initialized = True |
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if self.attn_impl == 'flash': |
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return (self.attn_bias, attention_mask) |
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if self.attn_bias is not None: |
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self.attn_bias = self.attn_bias.to(dtype=dtype, device=device) |
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attn_bias = self.attn_bias |
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if self.prefix_lm: |
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assert isinstance(attn_bias, torch.Tensor) |
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assert isinstance(prefix_mask, torch.Tensor) |
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attn_bias = self._apply_prefix_mask(attn_bias, prefix_mask) |
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if self.attn_uses_sequence_id and sequence_id is not None: |
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assert isinstance(attn_bias, torch.Tensor) |
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attn_bias = apply_sequence_id(attn_bias, sequence_id, self.config.max_seq_len) |
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if attention_mask is not None: |
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s_k = attention_mask.shape[-1] |
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if attn_bias is None: |
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attn_bias = torch.zeros((1, 1, 1, s_k), device=device, dtype=dtype) |
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else: |
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_s_k = max(0, attn_bias.size(-1) - s_k) |
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attn_bias = attn_bias[:, :, :, _s_k:] |
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if prefix_mask is not None and attention_mask.shape != prefix_mask.shape: |
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raise ValueError(f'attention_mask shape={attention_mask.shape} ' + f'and prefix_mask shape={prefix_mask.shape} are not equal.') |
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min_val = torch.finfo(attn_bias.dtype).min |
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attn_bias = attn_bias.masked_fill(~attention_mask.view(-1, 1, 1, s_k), min_val) |
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return (attn_bias, attention_mask) |
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|
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def _apply_prefix_mask(self, attn_bias: torch.Tensor, prefix_mask: torch.Tensor) -> torch.Tensor: |
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(s_k, s_q) = attn_bias.shape[-2:] |
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if s_k != self.config.max_seq_len or s_q != self.config.max_seq_len: |
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raise ValueError('attn_bias does not match the expected shape. ' + f'The last two dimensions should both be {self.config.max_length} ' + f'but are {s_k} and {s_q}.') |
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seq_len = prefix_mask.shape[-1] |
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if seq_len > self.config.max_seq_len: |
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raise ValueError(f'prefix_mask sequence length cannot exceed max_seq_len={self.config.max_seq_len}') |
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attn_bias = attn_bias[..., :seq_len, :seq_len] |
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causal = torch.tril(torch.ones((seq_len, seq_len), dtype=torch.bool, device=prefix_mask.device)).view(1, 1, seq_len, seq_len) |
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prefix = prefix_mask.view(-1, 1, 1, seq_len) |
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cannot_attend = ~torch.logical_or(causal, prefix.bool()) |
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min_val = torch.finfo(attn_bias.dtype).min |
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attn_bias = attn_bias.masked_fill(cannot_attend, min_val) |
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return attn_bias |
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|
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def forward(self, input_ids: Optional[torch.LongTensor]=None, past_key_values: Optional[List[Tuple[torch.FloatTensor]]]=None, attention_mask: Optional[torch.ByteTensor]=None, prefix_mask: Optional[torch.ByteTensor]=None, sequence_id: Optional[torch.LongTensor]=None, return_dict: Optional[bool]=None, output_attentions: Optional[bool]=None, output_hidden_states: Optional[bool]=None, use_cache: Optional[bool]=None, inputs_embeds: Optional[torch.Tensor]=None) -> BaseModelOutputWithPast: |
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return_dict = return_dict if return_dict is not None else self.config.return_dict |
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use_cache = use_cache if use_cache is not None else self.config.use_cache |
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if attention_mask is not None: |
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attention_mask = attention_mask.bool() |
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if prefix_mask is not None: |
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prefix_mask = prefix_mask.bool() |
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if not return_dict: |
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raise NotImplementedError('return_dict False is not implemented yet for MPT') |
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if output_attentions: |
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if self.attn_impl != 'torch': |
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raise NotImplementedError('output_attentions is not implemented for MPT when using attn_impl `flash` or `triton`.') |
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if self.training and attention_mask is not None and (attention_mask[:, 0].sum() != attention_mask.shape[0]): |
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raise NotImplementedError('MPT does not support training with left padding.') |
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if self.prefix_lm and prefix_mask is None: |
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raise ValueError('prefix_mask is a required argument when MPT is configured with prefix_lm=True.') |
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if self.training: |
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if self.attn_uses_sequence_id and sequence_id is None: |
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raise ValueError('sequence_id is a required argument when MPT is configured with attn_uses_sequence_id=True ' + 'and the model is in train mode.') |
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elif self.attn_uses_sequence_id is False and sequence_id is not None: |
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warnings.warn('MPT received non-None input for `sequence_id` but is configured with attn_uses_sequence_id=False. ' + 'This input will be ignored. If you want the model to use `sequence_id`, set attn_uses_sequence_id to True.') |
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if input_ids is not None and inputs_embeds is not None: |
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raise ValueError('You cannot specify both input_ids and inputs_embeds.') |
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elif input_ids is not None: |
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bsz = input_ids.size(0) |
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S = input_ids.size(1) |
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x = self.wte(input_ids) |
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input_device = input_ids.device |
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elif inputs_embeds is not None: |
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bsz = inputs_embeds.size(0) |
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S = inputs_embeds.size(1) |
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x = inputs_embeds |
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input_device = inputs_embeds.device |
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else: |
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raise ValueError('You must specify input_ids or inputs_embeds') |
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assert S <= self.config.max_seq_len, f'Cannot forward input with seq_len={S}, this model only supports seq_len<={self.config.max_seq_len}' |
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rotary_emb_w_meta_info = None |
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past_position = 0 |
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if past_key_values is not None: |
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if len(past_key_values) != self.config.n_layers: |
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raise ValueError(f'past_key_values must provide a past_key_value for each attention ' + f'layer in the network (len(past_key_values)={len(past_key_values)!r}; self.config.n_layers={self.config.n_layers!r}).') |
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past_position = past_key_values[0][0].size(1) |
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if self.attn_impl == 'torch': |
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past_position = past_key_values[0][0].size(3) |
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if self.learned_pos_emb or self.rope: |
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if self.learned_pos_emb and S + past_position > self.config.max_seq_len: |
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raise ValueError(f'Cannot forward input with past sequence length {past_position} and current sequence length ' + f'{S + 1}, this model only supports total sequence length <= {self.config.max_seq_len}.') |
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if self.learned_pos_emb or (self.rope and self.rope_impl == 'hf'): |
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pos = torch.arange(past_position, S + past_position, dtype=torch.long, device=input_device).unsqueeze(0) |
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if attention_mask is not None: |
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pos = torch.clamp(pos - torch.cumsum((~attention_mask).to(torch.int32), dim=1)[:, past_position:], min=0) |
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if self.learned_pos_emb: |
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x = x + self.wpe(pos) |
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elif self.rope and self.rope_impl == 'hf': |
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rotary_emb_w_meta_info = {'impl': self.rope_impl, 'rotary_emb': self.rotary_embedding, 'offset_info': pos, 'seq_len': S + past_position} |
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elif self.rope and self.rope_impl == 'dail': |
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rotary_emb_w_meta_info = {'impl': self.rope_impl, 'rotary_emb': self.rotary_embedding, 'offset_info': past_position, 'seq_len': S + past_position} |
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if self.embedding_fraction == 1: |
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x = self.emb_drop(x) |
|
else: |
|
x_shrunk = x * self.embedding_fraction + x.detach() * (1 - self.embedding_fraction) |
|
assert isinstance(self.emb_drop, nn.Module) |
|
x = self.emb_drop(x_shrunk) |
|
(attn_bias, attention_mask) = self._attn_bias(device=x.device, dtype=torch.float32, attention_mask=attention_mask, prefix_mask=prefix_mask, sequence_id=sequence_id) |
|
attention_mask_in_length = gen_attention_mask_in_length(sequence_id=sequence_id, S=S, attn_uses_sequence_id=self.attn_uses_sequence_id, attn_impl=self.attn_impl, attention_mask=attention_mask) |
|
alibi_slopes = None |
|
if self.alibi and self.attn_impl == 'flash': |
|
alibi_slopes = gen_slopes(n_heads=self.config.n_heads, alibi_bias_max=self.alibi_bias_max, device=x.device, return_1d=True) |
|
presents = () if use_cache else None |
|
if use_cache and past_key_values is None: |
|
past_key_values = [() for _ in range(self.config.n_layers)] |
|
all_hidden_states = () if output_hidden_states else None |
|
all_self_attns = () if output_attentions else None |
|
flash_attn_padding_info = {} |
|
if self.attn_impl == 'flash': |
|
flash_attn_padding_info = gen_flash_attn_padding_info(bsz, S, past_position, x.device, attention_mask_in_length, attention_mask) |
|
for (b_idx, block) in enumerate(self.blocks): |
|
if output_hidden_states: |
|
assert all_hidden_states is not None |
|
all_hidden_states = all_hidden_states + (x,) |
|
past_key_value = past_key_values[b_idx] if past_key_values is not None else None |
|
(x, attn_weights, present) = block(x, past_key_value=past_key_value, attn_bias=attn_bias, rotary_emb_w_meta_info=rotary_emb_w_meta_info, attention_mask=attention_mask, is_causal=self.is_causal, output_attentions=bool(output_attentions), alibi_slopes=alibi_slopes, flash_attn_padding_info=flash_attn_padding_info) |
|
if presents is not None: |
|
presents += (present,) |
|
if output_attentions: |
|
assert all_self_attns is not None |
|
all_self_attns = all_self_attns + (attn_weights,) |
|
x = self.norm_f(x) |
|
if output_hidden_states: |
|
assert all_hidden_states is not None |
|
all_hidden_states = all_hidden_states + (x,) |
|
return BaseModelOutputWithPast(last_hidden_state=x, past_key_values=presents, hidden_states=all_hidden_states, attentions=all_self_attns) |
|
|
|
def param_init_fn(self, module: nn.Module) -> None: |
|
init_fn_name = self.config.init_config['name'] |
|
MODEL_INIT_REGISTRY[init_fn_name](module=module, n_layers=self.config.n_layers, d_model=self.config.d_model, **self.config.init_config) |
|
|
|
def fsdp_wrap_fn(self, module: nn.Module) -> bool: |
|
return _fsdp_wrap_fn(self, module) |
|
|
|
def activation_checkpointing_fn(self, module: nn.Module) -> bool: |
|
return isinstance(module, MPTBlock) |
|
|
|
class MPTForCausalLM(MPTPreTrainedModel): |
|
|
|
def __init__(self, config: MPTConfig): |
|
super().__init__(config) |
|
log.info(f'Instantiating an MPTForCausalLM model from {__file__}') |
|
self.transformer: MPTModel = MPTModel(config) |
|
self.lm_head = None |
|
if not config.tie_word_embeddings: |
|
self.lm_head = nn.Linear(config.d_model, config.vocab_size, bias=False, device=config.init_device) |
|
self.lm_head._fsdp_wrap = True |
|
for child in self.transformer.children(): |
|
if isinstance(child, torch.nn.ModuleList): |
|
continue |
|
if isinstance(child, torch.nn.Module): |
|
child._fsdp_wrap = True |
|
self.logit_scale = None |
|
if config.logit_scale is not None: |
|
logit_scale = config.logit_scale |
|
if isinstance(logit_scale, str): |
|
if logit_scale == 'inv_sqrt_d_model': |
|
logit_scale = 1 / math.sqrt(config.d_model) |
|
else: |
|
raise ValueError(f"logit_scale={logit_scale!r} is not recognized as an option; use numeric value or 'inv_sqrt_d_model'.") |
|
self.logit_scale = logit_scale |
|
|
|
def get_input_embeddings(self) -> Union[SharedEmbedding, nn.Embedding]: |
|
return self.transformer.get_input_embeddings() |
|
|
|
def set_input_embeddings(self, value: Union[SharedEmbedding, nn.Embedding]) -> None: |
|
self.transformer.set_input_embeddings(value) |
|
|
|
def get_output_embeddings(self) -> Union[SharedEmbedding, nn.Embedding, nn.Linear]: |
|
if self.lm_head is not None: |
|
return self.lm_head |
|
return self.transformer.get_input_embeddings() |
|
|
|
def set_output_embeddings(self, new_embeddings: Union[SharedEmbedding, nn.Embedding, nn.Linear]) -> None: |
|
if self.lm_head is not None: |
|
self.lm_head = new_embeddings |
|
else: |
|
if not isinstance(new_embeddings, (SharedEmbedding, nn.Embedding)): |
|
raise ValueError('new_embeddings must be an instance of SharedEmbedding ' + f'or nn.Embedding, but got {type(new_embeddings)}.') |
|
warnings.warn('Using `set_output_embeddings` to set the embedding layer of ' + 'MPTForCausalLM with tied weights. Given weights are tied, ' + 'using `set_input_embeddings` is recommended over using ' + '`set_output_embeddings`.') |
|
self.transformer.set_input_embeddings(new_embeddings) |
|
|
|
def tie_weights(self) -> None: |
|
self.lm_head = None |
|
|
|
def set_decoder(self, decoder: MPTModel) -> None: |
|
self.transformer = decoder |
|
|
|
def get_decoder(self) -> MPTModel: |
|
return self.transformer |
|
|
|
def forward(self, input_ids: Optional[torch.LongTensor]=None, past_key_values: Optional[List[Tuple[torch.FloatTensor]]]=None, attention_mask: Optional[torch.ByteTensor]=None, prefix_mask: Optional[torch.ByteTensor]=None, sequence_id: Optional[torch.LongTensor]=None, labels: Optional[torch.LongTensor]=None, return_dict: Optional[bool]=None, output_attentions: Optional[bool]=None, output_hidden_states: Optional[bool]=None, use_cache: Optional[bool]=None, inputs_embeds: Optional[torch.FloatTensor]=None) -> CausalLMOutputWithPast: |
|
return_dict = return_dict if return_dict is not None else self.config.return_dict |
|
use_cache = use_cache if use_cache is not None else self.config.use_cache |
|
outputs = self.transformer(input_ids=input_ids, past_key_values=past_key_values, attention_mask=attention_mask, prefix_mask=prefix_mask, sequence_id=sequence_id, return_dict=return_dict, output_attentions=output_attentions, output_hidden_states=output_hidden_states, use_cache=use_cache, inputs_embeds=inputs_embeds) |
|
if self.lm_head is not None: |
|
logits = self.lm_head(outputs.last_hidden_state) |
|
else: |
|
out = outputs.last_hidden_state |
|
out = out.to(self.transformer.wte.weight.device) |
|
logits = self.transformer.wte(out, True) |
|
if self.logit_scale is not None: |
|
if self.logit_scale == 0: |
|
warnings.warn(f'Multiplying logits by self.logit_scale={self.logit_scale!r}. This will produce uniform (uninformative) outputs.') |
|
logits *= self.logit_scale |
|
loss = None |
|
if labels is not None: |
|
_labels = torch.roll(labels, shifts=-1) |
|
_labels[:, -1] = -100 |
|
loss = F.cross_entropy(logits.view(-1, logits.size(-1)), _labels.to(logits.device).view(-1)) |
|
return CausalLMOutputWithPast(loss=loss, logits=logits, past_key_values=outputs.past_key_values, hidden_states=outputs.hidden_states, attentions=outputs.attentions) |
|
|
|
def param_init_fn(self, module: nn.Module) -> None: |
|
init_fn_name = self.config.init_config['name'] |
|
MODEL_INIT_REGISTRY[init_fn_name](module=module, n_layers=self.config.n_layers, d_model=self.config.d_model, **self.config.init_config) |
|
|
|
def fsdp_wrap_fn(self, module: nn.Module) -> bool: |
|
return _fsdp_wrap_fn(self, module) |
|
|
|
def activation_checkpointing_fn(self, module: nn.Module) -> bool: |
|
act_ckpt_list = getattr(self.config, 'activation_checkpointing_target', None) or ['MPTBlock'] |
|
if isinstance(act_ckpt_list, str): |
|
act_ckpt_list = [act_ckpt_list] |
|
elif not isinstance(act_ckpt_list, list): |
|
raise ValueError(f'activation_checkpointing_target must be either a single string or a list, but got {type(act_ckpt_list)}') |
|
if 'MPTBlock' in act_ckpt_list or 'mptblock' in act_ckpt_list: |
|
if len(act_ckpt_list) > 1: |
|
log.info('Activation checkpointing MPTBlock only (ignoring other sub-block modules specified in activation_checkpointing_target).') |
|
return isinstance(module, MPTBlock) |
|
mod_types = () |
|
for mod_name in act_ckpt_list: |
|
if mod_name.lower() == 'mptblock': |
|
mod_types += (MPTBlock,) |
|
elif mod_name in ATTN_CLASS_REGISTRY: |
|
mod_types += (ATTN_CLASS_REGISTRY[mod_name],) |
|
elif mod_name in FFN_CLASS_REGISTRY: |
|
mod_types += (FFN_CLASS_REGISTRY[mod_name],) |
|
elif mod_name in NORM_CLASS_REGISTRY: |
|
mod_types += (NORM_CLASS_REGISTRY[mod_name],) |
|
else: |
|
msg = ', '.join(list(ATTN_CLASS_REGISTRY.keys()) + list(FFN_CLASS_REGISTRY.keys()) + list(NORM_CLASS_REGISTRY.keys()) + ['MPTBlock']) |
|
raise ValueError(f'{mod_name} (specified in activation_checkpointing_target) is not a recognized option out of available options {msg}.') |
|
return isinstance(module, mod_types) |
|
|
|
def prepare_inputs_for_generation(self, input_ids: torch.Tensor, past_key_values: Optional[List[Tuple[torch.Tensor, torch.Tensor]]]=None, inputs_embeds: Optional[torch.Tensor]=None, **kwargs: Any) -> Dict[str, Any]: |
|
attention_mask = kwargs['attention_mask'].bool() |
|
if attention_mask[:, -1].sum() != attention_mask.shape[0]: |
|
raise NotImplementedError('MPT does not support generation with right padding.') |
|
if self.transformer.attn_uses_sequence_id and self.training: |
|
sequence_id = torch.zeros_like(input_ids[:1]) |
|
else: |
|
sequence_id = None |
|
if past_key_values is not None: |
|
input_ids = input_ids[:, -1].unsqueeze(-1) |
|
if self.transformer.prefix_lm: |
|
prefix_mask = torch.ones_like(attention_mask) |
|
if kwargs.get('use_cache') == False: |
|
raise NotImplementedError('MPT with prefix_lm=True does not support use_cache=False.') |
|
else: |
|
prefix_mask = None |
|
if inputs_embeds is not None and past_key_values is None: |
|
model_inputs = {'inputs_embeds': inputs_embeds} |
|
else: |
|
model_inputs = {'input_ids': input_ids} |
|
model_inputs.update({'attention_mask': attention_mask, 'prefix_mask': prefix_mask, 'sequence_id': sequence_id, 'past_key_values': past_key_values, 'use_cache': kwargs.get('use_cache', True)}) |
|
return model_inputs |
|
|
|
@staticmethod |
|
def _reorder_cache(past_key_values: List[Tuple[torch.Tensor, torch.Tensor]], beam_idx: torch.LongTensor) -> List[Tuple[torch.Tensor, ...]]: |
|
"""Used by HuggingFace generate when using beam search with kv-caching. |
|
|
|
See https://github.com/huggingface/transformers/blob/3ec7a47664ebe40c40f4b722f6bb1cd30c3821ec/src/transformers/models/gpt2/modeling_gpt2.py#L1122-L1133 |
|
for an example in transformers. |
|
""" |
|
reordered_past = [] |
|
for layer_past in past_key_values: |
|
reordered_past += [tuple((past_state.index_select(0, beam_idx) for past_state in layer_past))] |
|
return reordered_past |
