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import random |
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import traceback |
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from pathlib import Path |
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import torch |
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from exllamav2 import ( |
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ExLlamaV2, |
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ExLlamaV2Cache, |
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ExLlamaV2Cache_8bit, |
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ExLlamaV2Config, |
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ExLlamaV2Tokenizer |
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) |
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from exllamav2.generator import ExLlamaV2BaseGenerator, ExLlamaV2Sampler |
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from modules import shared |
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from modules.logging_colors import logger |
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from modules.text_generation import get_max_prompt_length |
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try: |
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import flash_attn |
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except ModuleNotFoundError: |
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logger.warning( |
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'You are running ExLlamaV2 without flash-attention. This will cause the VRAM usage ' |
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'to be a lot higher than it could be.\n' |
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'Try installing flash-attention following the instructions here: ' |
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'https://github.com/Dao-AILab/flash-attention#installation-and-features' |
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) |
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pass |
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except Exception: |
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logger.warning('Failed to load flash-attention due to the following error:\n') |
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traceback.print_exc() |
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class Exllamav2Model: |
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def __init__(self): |
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pass |
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@classmethod |
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def from_pretrained(self, path_to_model): |
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path_to_model = Path(f'{shared.args.model_dir}') / Path(path_to_model) |
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config = ExLlamaV2Config() |
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config.model_dir = str(path_to_model) |
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config.prepare() |
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config.max_seq_len = shared.args.max_seq_len |
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config.scale_pos_emb = shared.args.compress_pos_emb |
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config.scale_alpha_value = shared.args.alpha_value |
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config.no_flash_attn = shared.args.no_flash_attn |
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model = ExLlamaV2(config) |
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split = None |
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if shared.args.gpu_split: |
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split = [float(alloc) for alloc in shared.args.gpu_split.split(",")] |
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model.load(split) |
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tokenizer = ExLlamaV2Tokenizer(config) |
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if shared.args.cache_8bit: |
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cache = ExLlamaV2Cache_8bit(model) |
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else: |
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cache = ExLlamaV2Cache(model) |
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generator = ExLlamaV2BaseGenerator(model, cache, tokenizer) |
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result = self() |
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result.model = model |
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result.cache = cache |
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result.tokenizer = tokenizer |
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result.generator = generator |
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result.loras = None |
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return result, result |
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def encode(self, string, **kwargs): |
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return self.tokenizer.encode(string, add_bos=True, encode_special_tokens=True) |
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def decode(self, ids, **kwargs): |
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if isinstance(ids, list): |
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ids = torch.tensor([ids]) |
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elif isinstance(ids, torch.Tensor) and ids.numel() == 1: |
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ids = ids.view(1, -1) |
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return self.tokenizer.decode(ids, decode_special_tokens=True)[0] |
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def get_logits(self, token_ids, **kwargs): |
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self.cache.current_seq_len = 0 |
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if token_ids.shape[-1] > 1: |
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self.model.forward(token_ids[:, :-1], self.cache, input_mask=None, preprocess_only=True, loras=self.loras) |
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return self.model.forward(token_ids[:, -1:], self.cache, input_mask=None, loras=self.loras, **kwargs).float().cpu() |
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def generate_with_streaming(self, prompt, state): |
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settings = ExLlamaV2Sampler.Settings() |
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settings.temperature = state['temperature'] |
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settings.top_k = state['top_k'] |
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settings.top_p = state['top_p'] |
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settings.typical = state['typical_p'] |
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settings.token_repetition_penalty = state['repetition_penalty'] |
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settings.token_repetition_range = -1 if state['repetition_penalty_range'] <= 0 else state['repetition_penalty_range'] |
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if state['ban_eos_token']: |
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settings.disallow_tokens(self.tokenizer, [self.tokenizer.eos_token_id]) |
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if state['custom_token_bans']: |
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to_ban = [int(x) for x in state['custom_token_bans'].split(',')] |
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if len(to_ban) > 0: |
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settings.disallow_tokens(self.tokenizer, to_ban) |
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ids = self.tokenizer.encode(prompt, add_bos=state['add_bos_token'], encode_special_tokens=True) |
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ids = ids[:, -get_max_prompt_length(state):] |
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initial_len = ids.shape[-1] |
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if state['auto_max_new_tokens']: |
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max_new_tokens = state['truncation_length'] - ids.shape[-1] |
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else: |
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max_new_tokens = state['max_new_tokens'] |
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self.cache.current_seq_len = 0 |
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self.model.forward(ids[:, :-1], self.cache, input_mask=None, preprocess_only=True, loras=self.loras) |
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has_leading_space = False |
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for i in range(max_new_tokens): |
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logits = self.model.forward(ids[:, -1:], self.cache, input_mask=None, loras=self.loras).float().cpu() |
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token, _, _ = ExLlamaV2Sampler.sample(logits, settings, ids, random.random(), self.tokenizer) |
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ids = torch.cat([ids, token], dim=1) |
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if i == 0 and self.tokenizer.tokenizer.IdToPiece(int(token)).startswith('▁'): |
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has_leading_space = True |
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decoded_text = self.tokenizer.decode(ids[:, initial_len:], decode_special_tokens=not state['skip_special_tokens'])[0] |
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if has_leading_space: |
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decoded_text = ' ' + decoded_text |
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yield decoded_text |
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if token.item() == self.tokenizer.eos_token_id or shared.stop_everything: |
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break |
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def generate(self, prompt, state): |
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output = '' |
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for output in self.generate_with_streaming(prompt, state): |
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pass |
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return output |
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