APIFo / extras /expansion.py
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# Fooocus GPT2 Expansion
# Algorithm created by Lvmin Zhang at 2023, Stanford
# If used inside Fooocus, any use is permitted.
# If used outside Fooocus, only non-commercial use is permitted (CC-By NC 4.0).
# This applies to the word list, vocab, model, and algorithm.
import os
import torch
import math
import ldm_patched.modules.model_management as model_management
from transformers.generation.logits_process import LogitsProcessorList
from transformers import AutoTokenizer, AutoModelForCausalLM, set_seed
from modules.config import path_fooocus_expansion
from ldm_patched.modules.model_patcher import ModelPatcher
# limitation of np.random.seed(), called from transformers.set_seed()
SEED_LIMIT_NUMPY = 2**32
neg_inf = - 8192.0
def safe_str(x):
x = str(x)
for _ in range(16):
x = x.replace(' ', ' ')
return x.strip(",. \r\n")
def remove_pattern(x, pattern):
for p in pattern:
x = x.replace(p, '')
return x
class FooocusExpansion:
def __init__(self):
self.tokenizer = AutoTokenizer.from_pretrained(path_fooocus_expansion)
positive_words = open(os.path.join(path_fooocus_expansion, 'positive.txt'),
encoding='utf-8').read().splitlines()
positive_words = ['Ġ' + x.lower() for x in positive_words if x != '']
self.logits_bias = torch.zeros((1, len(self.tokenizer.vocab)), dtype=torch.float32) + neg_inf
debug_list = []
for k, v in self.tokenizer.vocab.items():
if k in positive_words:
self.logits_bias[0, v] = 0
debug_list.append(k[1:])
print(f'Fooocus V2 Expansion: Vocab with {len(debug_list)} words.')
# debug_list = '\n'.join(sorted(debug_list))
# print(debug_list)
# t11 = self.tokenizer(',', return_tensors="np")
# t198 = self.tokenizer('\n', return_tensors="np")
# eos = self.tokenizer.eos_token_id
self.model = AutoModelForCausalLM.from_pretrained(path_fooocus_expansion)
self.model.eval()
load_device = model_management.text_encoder_device()
offload_device = model_management.text_encoder_offload_device()
# MPS hack
if model_management.is_device_mps(load_device):
load_device = torch.device('cpu')
offload_device = torch.device('cpu')
use_fp16 = model_management.should_use_fp16(device=load_device)
if use_fp16:
self.model.half()
self.patcher = ModelPatcher(self.model, load_device=load_device, offload_device=offload_device)
print(f'Fooocus Expansion engine loaded for {load_device}, use_fp16 = {use_fp16}.')
@torch.no_grad()
@torch.inference_mode()
def logits_processor(self, input_ids, scores):
assert scores.ndim == 2 and scores.shape[0] == 1
self.logits_bias = self.logits_bias.to(scores)
bias = self.logits_bias.clone()
bias[0, input_ids[0].to(bias.device).long()] = neg_inf
bias[0, 11] = 0
return scores + bias
@torch.no_grad()
@torch.inference_mode()
def __call__(self, prompt, seed):
if prompt == '':
return ''
if self.patcher.current_device != self.patcher.load_device:
print('Fooocus Expansion loaded by itself.')
model_management.load_model_gpu(self.patcher)
seed = int(seed) % SEED_LIMIT_NUMPY
set_seed(seed)
prompt = safe_str(prompt) + ','
tokenized_kwargs = self.tokenizer(prompt, return_tensors="pt")
tokenized_kwargs.data['input_ids'] = tokenized_kwargs.data['input_ids'].to(self.patcher.load_device)
tokenized_kwargs.data['attention_mask'] = tokenized_kwargs.data['attention_mask'].to(self.patcher.load_device)
current_token_length = int(tokenized_kwargs.data['input_ids'].shape[1])
max_token_length = 75 * int(math.ceil(float(current_token_length) / 75.0))
max_new_tokens = max_token_length - current_token_length
if max_new_tokens == 0:
return prompt[:-1]
# https://huggingface.co/blog/introducing-csearch
# https://huggingface.co/docs/transformers/generation_strategies
features = self.model.generate(**tokenized_kwargs,
top_k=100,
max_new_tokens=max_new_tokens,
do_sample=True,
logits_processor=LogitsProcessorList([self.logits_processor]))
response = self.tokenizer.batch_decode(features, skip_special_tokens=True)
result = safe_str(response[0])
return result