X-encoder / app.py
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import gradio as gr
from transformers import AutoModelForSequenceClassification, AutoTokenizer
import torch
# Load model and tokenizer
model_name = "cross-encoder/ms-marco-MiniLM-L-12-v2"
tokenizer = AutoTokenizer.from_pretrained(model_name)
model = AutoModelForSequenceClassification.from_pretrained(model_name)
model.eval()
# Function to compute relevance score and dynamically adjust threshold
def get_relevance_score_and_excerpt(query, paragraph, threshold_weight):
if not query.strip() or not paragraph.strip():
return "Please provide both a query and a document paragraph.", "", ""
# Tokenize the input
inputs = tokenizer(query, paragraph, return_tensors="pt", truncation=True, padding=True)
with torch.no_grad():
output = model(**inputs, output_attentions=True)
# Extract logits and calculate base relevance score
logit = output.logits.squeeze().item()
base_relevance_score = torch.sigmoid(torch.tensor(logit)).item()
# Calculate dynamic threshold using sigmoid-based formula
sigmoid_factor = 1 / (1 + torch.exp(-5 * (base_relevance_score - 0.5))).item()
dynamic_threshold = max(0.02, threshold_weight * sigmoid_factor)
# Extract attention scores (last layer)
attention = output.attentions[-1]
attention_scores = attention.mean(dim=1).mean(dim=0)
query_tokens = tokenizer.tokenize(query)
paragraph_tokens = tokenizer.tokenize(paragraph)
query_len = len(query_tokens) + 2 # +2 for special tokens [CLS] and first [SEP]
para_start_idx = query_len
para_end_idx = len(inputs["input_ids"][0]) - 1
if para_end_idx <= para_start_idx:
return round(base_relevance_score, 4), round(dynamic_threshold, 4), "No relevant tokens extracted."
para_attention_scores = attention_scores[para_start_idx:para_end_idx, para_start_idx:para_end_idx].mean(dim=0)
if para_attention_scores.numel() == 0:
return round(base_relevance_score, 4), round(dynamic_threshold, 4), "No relevant tokens extracted."
# Get indices of relevant tokens above dynamic threshold
relevant_indices = (para_attention_scores > dynamic_threshold).nonzero(as_tuple=True)[0].tolist()
# Reconstruct paragraph with bolded relevant tokens using HTML tags
highlighted_text = ""
for idx, token in enumerate(paragraph_tokens):
if idx in relevant_indices:
highlighted_text += f"<b>{token}</b> "
else:
highlighted_text += f"{token} "
highlighted_text = tokenizer.convert_tokens_to_string(highlighted_text.split())
return round(base_relevance_score, 4), round(dynamic_threshold, 4), highlighted_text
# Define Gradio interface with a slider for threshold adjustment
interface = gr.Interface(
fn=get_relevance_score_and_excerpt,
inputs=[
gr.Textbox(label="Query", placeholder="Enter your search query..."),
gr.Textbox(label="Document Paragraph", placeholder="Enter a paragraph to match..."),
gr.Slider(minimum=0.02, maximum=0.5, value=0.1, step=0.01, label="Threshold Weight")
],
outputs=[
gr.Textbox(label="Relevance Score"),
gr.Textbox(label="Dynamic Threshold"),
gr.HTML(label="Highlighted Document Paragraph")
],
title="Cross-Encoder Attention Highlighting",
description="Adjust the threshold weight to influence dynamic token highlighting based on relevance.",
allow_flagging="never",
live=True
)
if __name__ == "__main__":
interface.launch()