tiny-layoutlm / make-tiny-layoutlm.py
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#!/usr/bin/env python
import sys
import os
from transformers import LayoutLMTokenizer, LayoutLMTokenizerFast, LayoutLMConfig, LayoutLMForMaskedLM
mname_orig = "microsoft/layoutlm-base-uncased"
mname_tiny = "tiny-layoutlm"
### Tokenizer
import json
from transformers import AutoTokenizer
from tokenizers import Tokenizer
vocab_keep_items = 5000
tokenizer = AutoTokenizer.from_pretrained(mname_orig, use_fast=True)
assert tokenizer.is_fast, "This only works for fast tokenizers."
tokenizer_json = json.loads(tokenizer._tokenizer.to_str())
vocab = tokenizer_json["model"]["vocab"]
if tokenizer_json["model"]["type"] == "BPE":
new_vocab = { token: i for token, i in vocab.items() if i < vocab_keep_items }
merges = tokenizer_json["model"]["merges"]
new_merges = []
for i in range(len(merges)):
a, b = merges[i].split()
new_token = "".join((a, b))
if a in new_vocab and b in new_vocab and new_token in new_vocab:
new_merges.append(merges[i])
tokenizer_json["model"]["merges"] = new_merges
elif tokenizer_json["model"]["type"] == "Unigram":
new_vocab = vocab[:vocab_keep_items]
elif tokenizer_json["model"]["type"] == "WordPiece" or tokenizer_json["model"]["type"] == "WordLevel":
new_vocab = { token: i for token, i in vocab.items() if i < vocab_keep_items }
else:
raise ValueError(f"don't know how to handle {tokenizer_json['model']['type']}")
tokenizer_json["model"]["vocab"] = new_vocab
tokenizer._tokenizer = Tokenizer.from_str(json.dumps(tokenizer_json))
tokenizer_fast_tiny = tokenizer
### Config
config_tiny = LayoutLMConfig.from_pretrained(mname_orig)
print(config_tiny)
# remember to update this to the actual config as each model is different and then shrink the numbers
config_tiny.update(dict(
vocab_size=vocab_keep_items,
hidden_size=32,
intermediate_size=64,
max_position_embeddings=512,
max_2d_position_embeddings=128,
num_attention_heads=2,
num_hidden_layers=2,
))
print("New config", config_tiny)
### Model
model_tiny = LayoutLMForMaskedLM(config_tiny)
print(f"{mname_tiny}: num of params {model_tiny.num_parameters()}")
model_tiny.resize_token_embeddings(len(tokenizer_fast_tiny))
# Test
inputs = tokenizer_fast_tiny("The capital of France is [MASK].", return_tensors="pt")
#print(inputs)
outputs = model_tiny(**inputs)
print("Test with normal tokenizer:", len(outputs.logits[0]))
# Save
model_tiny.half() # makes it smaller
model_tiny.save_pretrained(".")
tokenizer_fast_tiny.save_pretrained(".")
#print(model_tiny)
readme = "README.md"
if not os.path.exists(readme):
with open(readme, "w") as f:
f.write(f"This is a {mname_tiny} random model to be used for basic testing.\n")
print(f"Generated {mname_tiny}")