app.py

import os, json, random
import torch
import gradio as gr
import spaces
from transformers import AutoConfig, AutoModelForCausalLM, AutoTokenizer, TextIteratorStreamer
from huggingface_hub import login, hf_hub_download
import pyreft
import pyvene as pv
from threading import Thread
from typing import Iterator
import torch.nn.functional as F

HF_TOKEN = os.environ.get("HF_TOKEN")
login(token=HF_TOKEN)

MAX_MAX_NEW_TOKENS = 2048
DEFAULT_MAX_NEW_TOKENS = 128  # smaller default to save memory
MAX_INPUT_TOKEN_LENGTH = 4096

css = """
#alert-message textarea {
    background-color: #e8f4ff;
    border: 1px solid #cce5ff;
    color: #084298;
    font-size: 1.1em;
    padding: 12px;
    border-radius: 4px;
    font-weight: 500;
}

.concept-help {
    font-size: 0.9em;
    color: #666;
    margin-top: 4px;
    font-style: italic;
}
"""

def load_jsonl(jsonl_path):
    jsonl_data = []
    with open(jsonl_path, 'r') as f:
        for line in f:
            data = json.loads(line)
            jsonl_data.append(data)
    return jsonl_data

class Steer(pv.SourcelessIntervention):
    """Steer model via activation addition"""
    def __init__(self, **kwargs):
        super().__init__(**kwargs, keep_last_dim=True)
        self.proj = torch.nn.Linear(
                self.embed_dim, kwargs["latent_dim"], bias=False)
        self.subspace_generator = kwargs["subspace_generator"]
        
    def steer(self, base, source=None, subspaces=None):
        if subspaces["steer"]["subspace_gen_inputs"] is not None:
            # we call our subspace generator to generate the subspace on-the-fly.
            raw_steering_vec = self.subspace_generator(
                subspaces["steer"]["subspace_gen_inputs"]["input_ids"],
                subspaces["steer"]["subspace_gen_inputs"]["attention_mask"],
            )[0]
            steering_vec = torch.tensor(subspaces["steer"]["mag"]) * \
                raw_steering_vec.unsqueeze(dim=0)
            return base + steering_vec
        else:
            steering_vec = torch.tensor(subspaces["steer"]["mag"]) * \
                self.proj.weight[subspaces["steer"]["idx"]].unsqueeze(dim=0)
        return base + steering_vec
        
    def forward(self, base, source=None, subspaces=None):
        if subspaces == None:
            return base
        if subspaces["detect"] is not None:
            if subspaces["detect"]["subspace_gen_inputs"] is not None:
                # we call our subspace generator to generate the subspace on-the-fly.
                raw_detection_vec = self.subspace_generator(
                    subspaces["detect"]["subspace_gen_inputs"]["input_ids"],
                    subspaces["detect"]["subspace_gen_inputs"]["attention_mask"],
                )[0].unsqueeze(dim=-1)
            else:
                raw_detection_vec = self.proj.weight[subspaces["detect"]["idx"]].unsqueeze(dim=-1)
            print(base.shape)
            print(raw_detection_vec.shape)
            detection_latent = torch.matmul(base, raw_detection_vec.to(base.dtype)).squeeze(dim=-1) # (batch_size, seq, 1) -> (batch_size, seq)
            max_latent = torch.max(detection_latent, dim=-1).values[0] # (batch_size, seq) -> (batch_size)
            print("max_latent", max_latent)
            if max_latent > torch.tensor(subspaces["detect"]["mag"]):
                print("Detected!")
                return self.steer(base, source, subspaces)
            else:
                return base
        else:
            return self.steer(base, source, subspaces)
        
class RegressionWrapper(torch.nn.Module):
    def __init__(self, base_model, hidden_size, output_dim):
        super().__init__()
        self.base_model = base_model
        self.regression_head = torch.nn.Linear(hidden_size, output_dim)

    def forward(self, input_ids, attention_mask):
        outputs = self.base_model.model(
            input_ids=input_ids, 
            attention_mask=attention_mask,
            output_hidden_states=True,
            return_dict=True
        )
        last_hiddens = outputs.hidden_states[-1]
        last_token_representations = last_hiddens[:, -1]
        preds = self.regression_head(last_token_representations)
        preds = F.normalize(preds, p=2, dim=-1)
        return preds

# Check GPU
if not torch.cuda.is_available():
    print("Warning: Running on CPU, may be slow.")

# Load model & dictionary
model_id = "google/gemma-2-2b-it"
pv_model = None
tokenizer = None
concept_list = []
concept_id_map = {}
if torch.cuda.is_available():
    model = AutoModelForCausalLM.from_pretrained(
        model_id, device_map="cuda", torch_dtype=torch.bfloat16
    )
    tokenizer = AutoTokenizer.from_pretrained(model_id)

    # Download dictionary
    weight_path = hf_hub_download(repo_id="pyvene/gemma-reft-2b-it-res", filename="l20/weight.pt")
    meta_path = hf_hub_download(repo_id="pyvene/gemma-reft-2b-it-res", filename="l20/metadata.jsonl")
    params = torch.load(weight_path).cuda()
    md = load_jsonl(meta_path)

    concept_list = [item["concept"] for item in md]
    concept_id_map = {}

    # the reason to reindex is because there is one concept that is missing.
    concept_reindex = 0
    for item in md:
        concept_id_map[item["concept"]] = concept_reindex
        concept_reindex += 1

    # load subspace generator.
    base_tokenizer = AutoTokenizer.from_pretrained(
        f"google/gemma-2-2b", model_max_length=512)
    config = AutoConfig.from_pretrained("google/gemma-2-2b")
    base_model = AutoModelForCausalLM.from_config(config)
    
    subspace_generator_weight_path = hf_hub_download(repo_id="pyvene/gemma-reft-2b-it-res-generator", filename="l20/weight.pt")
    hidden_size = base_model.config.hidden_size
    subspace_generator = RegressionWrapper(
        base_model, hidden_size, hidden_size).bfloat16().to("cuda")
    subspace_generator.load_state_dict(torch.load(subspace_generator_weight_path))
    print(f"Loading model from saved file {subspace_generator_weight_path}")
    _ = subspace_generator.eval()

    steer = Steer(
        embed_dim=params.shape[0], latent_dim=params.shape[1], 
        subspace_generator=subspace_generator)
    steer.proj.weight.data = params.float()

    pv_model = pv.IntervenableModel({
        "component": f"model.layers[20].output",
        "intervention": steer}, model=model)

terminators = [tokenizer.eos_token_id] if tokenizer else []

@spaces.GPU
def generate(
    message: str,
    chat_history: list[tuple[str, str]],
    detection_list: list[dict],
    steering_list: list[dict],
    max_new_tokens: int=DEFAULT_MAX_NEW_TOKENS,
) -> Iterator[str]:

    # limit to last 4 turns
    start_idx = max(0, len(chat_history) - 4)
    recent_history = chat_history[start_idx:]

    # build list of messages
    messages = []
    for rh in recent_history:
        messages.append({"role": rh["role"], "content": rh["content"]})
    messages.append({"role": "user", "content": message})

    input_ids = torch.tensor([tokenizer.apply_chat_template(
        messages, tokenize=True, add_generation_prompt=True)]).cuda()

    # trim if needed
    if input_ids.shape[1] > MAX_INPUT_TOKEN_LENGTH:
        input_ids = input_ids[:, -MAX_INPUT_TOKEN_LENGTH:]
        yield "[Truncated prior text]\n"

    streamer = TextIteratorStreamer(tokenizer, timeout=10.0, skip_prompt=True, skip_special_tokens=True)
    print("detection_list: ", detection_list)
    print("steering_list: ", steering_list)
    generate_kwargs = {
        "base": {"input_ids": input_ids},
        "unit_locations": None,
        "max_new_tokens": max_new_tokens,
        "intervene_on_prompt": True,
        "subspaces": [
            {
                "detect": {
                    "idx": int(detection_list[0]["idx"]),
                    "mag": detection_list[0]["internal_mag"]*50,
                    "subspace_gen_inputs": base_tokenizer(detection_list[0]["subspace_gen_text"], return_tensors="pt").to("cuda") \
                        if detection_list[0]["subspace_gen_text"] is not None else None
                } if detection_list else None,
                "steer": {
                    "idx": int(steering_list[0]["idx"]),
                    "mag": steering_list[0]["internal_mag"]*50,
                    "subspace_gen_inputs": base_tokenizer(steering_list[0]["subspace_gen_text"], return_tensors="pt").to("cuda") \
                        if steering_list[0]["subspace_gen_text"] is not None else None
                }
            }
        ] if steering_list else None, # if steering is not provided, we do not steer.
        "streamer": streamer,
        "do_sample": True
    }

    t = Thread(target=pv_model.generate, kwargs=generate_kwargs)
    t.start()

    partial_text = []
    for token_str in streamer:
        partial_text.append(token_str)
        yield "".join(partial_text)

def filter_concepts(search_text: str):
    if not search_text.strip():
        return concept_list[:500]
    filtered = [c for c in concept_list if search_text.lower() in c.lower()]
    return filtered[:500]

def add_concept_to_list(selected_concept, user_slider_val, current_list):
    if not selected_concept:
        return current_list

    selected_concept_text = None
    if selected_concept.startswith("[New] "):
        selected_concept_text = selected_concept[6:]
        idx = 0
    else:
        idx = concept_id_map[selected_concept]
    internal_mag = user_slider_val
    new_entry = {
        "text": selected_concept,
        "idx": idx,
        "display_mag": user_slider_val,
        "internal_mag": internal_mag,
        "subspace_gen_text": selected_concept_text
    }
    # Add to the beginning of the list
    current_list = [new_entry]
    return current_list

def update_dropdown_choices(search_text, is_detection=False):
    filtered = filter_concepts(search_text)
    if not filtered or len(filtered) == 0:
        alert_message = (
            "Good news! Based on the topic you provided, we will automatically generate a detector for you!"
        ) if is_detection else (
            "Good news! Based on the topic you provided, we will automatically generate a steering vector. Try it out by starting a chat!"
        )
        
        return gr.update(
            choices=[],
            value=None,
            interactive=True
        ), gr.Textbox(
            label="No matching topics found", 
            value=alert_message,
            lines=3,
            interactive=False,
            visible=True,
            elem_id="alert-message"
        )
    
    return gr.update(
        choices=filtered,
        value=filtered[0],
        interactive=True,
        visible=True
    ), gr.Textbox(visible=False)

with gr.Blocks(css=css, fill_height=True) as demo:
    selected_detection = gr.State([])
    selected_subspaces = gr.State([])
    
    with gr.Row(min_height=500, equal_height=True):
        # Left side: chat area
        with gr.Column(scale=7):
            gr.Markdown("""# Conditionally Steer AI Responses Based on Topics""")
            gr.Markdown("""This is an experimental chatbot that you can steer using topics you care about:

Step 1: Choose a topic (e.g., "Google") to detect       
Step 2: Choose a topic (e.g., "ethics") you want the model to discuss when the previous topic comes up

We intervene on Gemma-2-2B-it by adding steering vectors to the residual stream at layer 20.""")
            chat_interface = gr.ChatInterface(
                fn=generate,
                chatbot=gr.Chatbot(),
                textbox=gr.Textbox(placeholder="List some search engines with their pros and cons", container=True, scale=7, submit_btn=True),
                additional_inputs=[selected_detection, selected_subspaces],
            )
        
        # Right side: concept detection and steering
        with gr.Column(scale=3):
            gr.Markdown("""#### Step 1: Choose a topic the model needs to recognize.""")
            with gr.Group():                
                detect_search = gr.Textbox(
                    label="Search for topics to detect",
                    placeholder="Try: 'Google'",
                    lines=1,
                )
                detect_msg = gr.TextArea(visible=False)
                detect_dropdown = gr.Dropdown(
                    label="Choose a topic to detect (Click to see more!)",
                    interactive=True,
                    allow_custom_value=False,
                )
                detect_threshold = gr.Slider(
                    label="Detection sensitivity",
                    minimum=0,
                    maximum=1,
                    step=0.1,
                    value=0.5,
                )

            gr.Markdown("---")

            gr.Markdown("""#### Step 2: Choose another topic the model needs to discuss when it detects the topic above.""")
            
            with gr.Group():                
                search_box = gr.Textbox(
                    label="Search topics to steer",
                    placeholder="Try: 'ethics'",
                    lines=1,
                )
                msg = gr.TextArea(visible=False)
                concept_dropdown = gr.Dropdown(
                    label="Choose a topic to steer the model (Click to see more!)",
                    interactive=True,
                    allow_custom_value=False,
                )
                concept_magnitude = gr.Slider(
                    label="Steering intensity",
                    minimum=-5,
                    maximum=5,
                    step=0.1,
                    value=3.5,
                )

    # Wire up events for detection
    detect_search.input(
        lambda x: update_dropdown_choices(x, is_detection=True),
        [detect_search],
        [detect_dropdown, detect_msg]
    ).then(
        add_concept_to_list,
        [detect_dropdown, detect_threshold, selected_detection],
        [selected_detection]
    )

    detect_dropdown.select(
        add_concept_to_list,
        [detect_dropdown, detect_threshold, selected_detection],
        [selected_detection]
    )

    detect_threshold.input(
        add_concept_to_list,
        [detect_dropdown, detect_threshold, selected_detection],
        [selected_detection]
    )

    # Wire up events for steering
    search_box.input(
        lambda x: update_dropdown_choices(x, is_detection=False),
        [search_box],
        [concept_dropdown, msg]
    ).then(
        add_concept_to_list,
        [concept_dropdown, concept_magnitude, selected_subspaces],
        [selected_subspaces]
    )

    concept_dropdown.select(
        add_concept_to_list,
        [concept_dropdown, concept_magnitude, selected_subspaces],
        [selected_subspaces]
    )
    
    concept_magnitude.input(
        add_concept_to_list,
        [concept_dropdown, concept_magnitude, selected_subspaces],
        [selected_subspaces]
    )

    demo.launch(share=True, height=1000)