app.py

import gradio as gr
import torch
from torch import nn

import numpy as np
import pandas as pd

from utils import compute_features
from scipy.stats import nbinom


class NegBinomialModel(nn.Module):
    def __init__(self, in_features):
        super().__init__()
        self.linear = nn.Linear(in_features, 1)
        self.alpha = nn.Parameter(torch.tensor(0.5))

    def forward(self, x):
        # safer activation than exp()
        mu = torch.exp(torch.clamp(self.linear(x), min=-5, max=5))
        alpha = torch.clamp(self.alpha, min=1e-3, max=10)
        return mu.squeeze(), alpha

    
model = NegBinomialModel(16)
model.load_state_dict(torch.load("model_weights.pt", map_location='cpu'))
model.eval()

# MU_BANKS = 2.6035915713614286
# STD_BANKS = 3.0158890435512125


def predict_score(lat, lon):
    # Convert input to tensor
    # inputs = torch.tensor([[lat, lon]], dtype=torch.float32)
    inputs = compute_features((lat,lon))
    print("[INPUTS]", inputs)
    num_banks = inputs.pop("num_banks_in_radius", 0)

    inputs = torch.tensor([lat,lon] + list(inputs.values()), dtype=torch.float32)

    # Get model output
    with torch.no_grad():
        mu_pred, alpha = model(inputs)

    # Unpack into respective values
    mu_pred = mu_pred.numpy().flatten()

    # r = 1/alpha
    # p = r / (r + mu_pred)

    # # Compute pmf and mode
    # k_mode = int((r - 1) * (1 - p) / p)  # mode of NB
    # p_k = nbinom.pmf(num_banks, r, p)
    # p_mode = nbinom.pmf(k_mode, r, p)

    # # Score normalized 0–100
    # score = (p_k / p_mode) * 100
    # score = np.clip(score, 0, 100)

    # diff = (num_banks - mu_pred) / (mu_pred + 1e-6)
    # # score = (1 - np.tanh(diff))

    # print("[TANH]", np.tanh(diff))

    diff = mu_pred - num_banks
    score = 100 / (1 + np.exp(-alpha * diff))

    score = np.abs(1 + np.tanh(diff)) / 2 * 100


    # score = (1 * np.abs(mu_pred + 0.1)) * 100

    # You can apply any post-processing here
    return (
        round(float(score), 3),
        num_banks,
        round(float(mu_pred), 3),
        # round(float(log_score),3)
        # "Normal Score": round(float(normal_score), 3),
    )

# ======== Gradio Interface ========
interface = gr.Interface(
    fn=predict_score,
    inputs=[
        gr.Number(label="Latitude"),
        gr.Number(label="Longitude"),
    ],
    outputs=[
        gr.Number(label="Score (0 - 100)"),
        gr.Number(label="Number of Current Banks"),
        gr.Number(label="Number of Ideal Banks"),
        # gr.Number(label="Log Score Probability"),
    ],
    title="Bank Location Scoring Model",
    description="Enter latitude and longitude to get the predicted score, number of banks, and normalized score.",
)


interface.launch()