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Update app.py
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def main():
"""
Creates a Streamlit web app that classifies a given body of text as either human-made or AI-generated,
using a pre-trained model.
"""
import streamlit as st
import numpy as np
import joblib
import string
import time
import scipy
import spacy
import re
from transformers import AutoTokenizer
import torch
from eli5.lime import TextExplainer
from eli5.lime.samplers import MaskingTextSampler
import eli5
import shap
from custom_models import HF_DistilBertBasedModelAppDocs, HF_BertBasedModelAppDocs
# Initialize Spacy
nlp = spacy.load("en_core_web_sm")
# device to run DL model
device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')
def format_text(text: str) -> str:
"""
This function takes a string as input and returns a formatted version of the string.
The function replaces specific substrings in the input string with empty strings,
converts the string to lowercase, removes any leading or trailing whitespace,
and removes any punctuation from the string.
"""
text = nlp(text)
text = " ".join([token.text for token in text if token.ent_type_ not in ["PERSON", "DATE"]])
pattern = r"\b[A-Za-z]+\d+\b"
text = re.sub(pattern, "", text)
return text.replace("REDACTED", "").lower().replace("[Name]", "").replace("[your name]", "").\
replace("dear admissions committee,", "").replace("sincerely,","").\
replace("[university's name]","fordham").replace("dear sir/madam,","").\
replace("โ€“ statement of intent ","").\
replace('program: master of science in data analytics name of applicant: ',"").\
replace("data analytics", "data science").replace("| \u200b","").\
replace("m.s. in data science at lincoln center ","").\
translate(str.maketrans('', '', string.punctuation)).strip().lstrip()
# Define the function to classify text
def nb_lr(model, text: str) -> (int, float):
"""
This function takes a previously trained Sklearn Pipeline
model (NaiveBayes or Logistic Regression), then returns prediction probability,
and the final prediction as a tuple.
"""
# Clean and format the input text
text = format_text(text)
# Predict using either LR or NB and get prediction probability
prediction = model.predict([text]).item()
predict_proba = round(model.predict_proba([text]).squeeze()[prediction].item(),4)
return prediction, predict_proba
def torch_pred(tokenizer, model, text):
"""
This function takes a pre-trained tokenizer, a previously trained transformer-based model
model (DistilBert or Bert), then returns prediction probability,
and the final prediction as a tuple.
"""
# DL models (BERT/DistilBERT based models)
cleaned_text_tokens = tokenizer([text], padding='max_length', max_length=512, truncation=True)
with torch.inference_mode():
input_ids, att = cleaned_text_tokens["input_ids"], cleaned_text_tokens["attention_mask"]
input_ids = torch.tensor(input_ids).to(device)
attention_mask = torch.tensor(att).to(device)
logits = model(input_ids=input_ids, attention_mask=attention_mask)
_, prediction = torch.max(logits, 1)
prediction = prediction.item()
predict_proba = round(torch.softmax(logits, 1).cpu().squeeze().tolist()[prediction],4)
return prediction, predict_proba
def pred_str(prediction:int) -> str:
"""
This function takes an integer value as input and returns a string representing the type of the input's source.
The input is expected to be a prediction from a classification model that distinguishes between human-made and AI-generated text.
"""
# Map the predicted class to string output
if prediction == 0:
return "Human-made ๐Ÿคทโ€โ™‚๏ธ๐Ÿคทโ€โ™€๏ธ"
else:
return "Generated with AI ๐Ÿฆพ"
@st.cache(allow_output_mutation=True, suppress_st_warning=True)
def load_tokenizer(option):
"""
Load pre-trained tokenizer and and save in cache memory.
"""
if option == "BERT-based model":
tokenizer = AutoTokenizer.from_pretrained("bert-base-uncased", padding='max_length', max_length=512, truncation=True)
else:
tokenizer = AutoTokenizer.from_pretrained("distilbert-base-uncased", padding='max_length', max_length=512, truncation=True)
return tokenizer
@st.cache(allow_output_mutation=True, suppress_st_warning=True)
def load_model(option):
"""
Load trained Transformer-based models and save in cache memory.
"""
if option == "BERT-based model":
model = HF_BertBasedModelAppDocs.from_pretrained("ferdmartin/HF_BertBasedModelAppDocs2").to(device)
else:
model = HF_DistilBertBasedModelAppDocs.from_pretrained("ferdmartin/HF_DistilBertBasedModelAppDocs2").to(device)
return model
# Streamlit app:
# List of models available
models_available = {"Logistic Regression":"models/baseline_model_lr2.joblib",
"Naive Bayes": "models/baseline_model_nb2.joblib",
"DistilBERT-based model (BERT light)": "ferdmartin/HF_DistilBertBasedModelAppDocs",
"BERT-based model": "ferdmartin/HF_BertBasedModelAppDocs"
}
st.set_page_config(page_title="AI/Human GradAppDocs", page_icon="๐Ÿค–", layout="wide")
st.title("Academic Application Document Classifier")
st.header("Is it human-made ๐Ÿ“ or Generated with AI ๐Ÿค– ? ")
# Check the model to use
def restore_prediction_state():
"""Restore session_state variable to clear prediction after changing model"""
if "prediction" in st.session_state:
del st.session_state.prediction
option = st.selectbox("Select a model to use:", models_available, on_change=restore_prediction_state)
# Load the selected trained model
if option in ("BERT-based model", "DistilBERT-based model (BERT light)"):
tokenizer = load_tokenizer(option)
model = load_model(option)
else:
model = joblib.load(models_available[option])
text = st.text_area("Enter either a statement of intent or a letter of recommendation:")
#Hide footer "made with streamlit"
hide_st_style = """
<style>
footer {visibility: hidden;}
header {visibility: hidden;}
</style>
"""
st.markdown(hide_st_style, unsafe_allow_html=True)
# Use model
if st.button("Let's check this text!"):
if text.strip() == "":
# In case there is no input for the model
st.error("Please enter some text")
else:
with st.spinner("Wait for the magic ๐Ÿช„๐Ÿ”ฎ"):
# Use models
if option in ("Naive Bayes", "Logistic Regression"): # Use Sklearn pipeline models
prediction, predict_proba = nb_lr(model, text)
st.session_state["sklearn"] = True
else:
prediction, predict_proba = torch_pred(tokenizer, model, text) # Use transformers
st.session_state["torch"] = True
# Store the result in session state
st.session_state["color_pred"] = "blue" if prediction == 0 else "red" # Set color for prediction output string
prediction = pred_str(prediction) # Map predictions (int => str)
st.session_state["prediction"] = prediction
st.session_state["predict_proba"] = predict_proba
st.session_state["text"] = text
# Print result
st.markdown(f"I think this text is: **:{st.session_state['color_pred']}[{st.session_state['prediction']}]** (Prediction probability: {st.session_state['predict_proba'] * 100}%)")
elif "prediction" in st.session_state:
# Display the stored result if available
st.markdown(f"I think this text is: **:{st.session_state['color_pred']}[{st.session_state['prediction']}]** (Prediction probability: {st.session_state['predict_proba'] * 100}%)")
if st.button("Model Explanation"):
# Check if there's text in the session state
if "text" in st.session_state and "prediction" in st.session_state:
if option in ("Naive Bayes", "Logistic Regression"):
with st.spinner('Wait for it ๐Ÿ’ญ...'):
explainer = TextExplainer(sampler=MaskingTextSampler())
explainer.fit(st.session_state["text"], model.predict_proba)
html = eli5.format_as_html(explainer.explain_prediction(target_names=["Human", "AI"]))
else:
with st.spinner('Wait for it ๐Ÿ’ญ... BERT-based model explanations take around 4-10 minutes. In case you want to abort, refresh the page.'):
def f(x):
"""TORCH EXPLAINER PRED FUNC (USES logits)"""
tv = torch.tensor([tokenizer.encode(v, padding='max_length', max_length=512, truncation=True) for v in x])#.cuda()
outputs = model(tv).detach().cpu().numpy()
scores = (np.exp(outputs).T / np.exp(outputs).sum(-1)).T
val = scipy.special.logit(scores[:,1]) # use one vs rest logit units
return val
explainer = shap.Explainer(f, tokenizer) # build explainer using masking tokens and selected transformer-based model
shap_values = explainer([st.session_state["text"]], fixed_context=1)
html = shap.plots.text(shap_values, display=False)
# Render HTML
st.components.v1.html(html, height=500, scrolling = True)
else:
st.error("Please enter some text and click 'Let's check!' before requesting an explanation.")
if __name__ == "__main__":
main()