app.py

import numpy as np
import tensorflow as tf
import tensorflow.keras as keras
import gradio as gr
import matplotlib.pyplot as plt
from huggingface_hub import from_pretrained_keras


# download the already pushed model
trained_models = [from_pretrained_keras("buio/attention_mil_classification")]


POSITIVE_CLASS = 1
BAG_COUNT = 1000
VAL_BAG_COUNT = 300
BAG_SIZE = 3
PLOT_SIZE = 1
ENSEMBLE_AVG_COUNT = 1

def create_bags(input_data, input_labels, positive_class, bag_count, instance_count):

    # Set up bags.
    bags = []
    bag_labels = []

    # Normalize input data.
    input_data = np.divide(input_data, 255.0)

    # Count positive samples.
    count = 0

    for _ in range(bag_count):

        # Pick a fixed size random subset of samples.
        index = np.random.choice(input_data.shape[0], instance_count, replace=False)
        instances_data = input_data[index]
        instances_labels = input_labels[index]

        # By default, all bags are labeled as 0.
        bag_label = 0

        # Check if there is at least a positive class in the bag.
        if positive_class in instances_labels:

            # Positive bag will be labeled as 1.
            bag_label = 1
            count += 1

        bags.append(instances_data)
        bag_labels.append(np.array([bag_label]))

    print(f"Positive bags: {count}")
    print(f"Negative bags: {bag_count - count}")

    return (list(np.swapaxes(bags, 0, 1)), np.array(bag_labels))

# Load the MNIST dataset.
(x_train, y_train), (x_val, y_val) = keras.datasets.mnist.load_data()

# Create validation data.
val_data, val_labels = create_bags(
    x_val, y_val, POSITIVE_CLASS, VAL_BAG_COUNT, BAG_SIZE
)


def predict(data, labels, trained_models):

    # Collect info per model.
    models_predictions = []
    models_attention_weights = []
    models_losses = []
    models_accuracies = []

    for model in trained_models:

        # Predict output classes on data.
        predictions = model.predict(data)
        models_predictions.append(predictions)

        # Create intermediate model to get MIL attention layer weights.
        intermediate_model = keras.Model(model.input, model.get_layer("alpha").output)

        # Predict MIL attention layer weights.
        intermediate_predictions = intermediate_model.predict(data)

        attention_weights = np.squeeze(np.swapaxes(intermediate_predictions, 1, 0))
        models_attention_weights.append(attention_weights)

        model.compile(loss="sparse_categorical_crossentropy", metrics=["accuracy"])
        loss, accuracy = model.evaluate(data, labels, verbose=0)
        models_losses.append(loss)
        models_accuracies.append(accuracy)

    print(
        f"The average loss and accuracy are {np.sum(models_losses, axis=0) / ENSEMBLE_AVG_COUNT:.2f}"
        f" and {100 * np.sum(models_accuracies, axis=0) / ENSEMBLE_AVG_COUNT:.2f} % resp."
    )

    return (
        np.sum(models_predictions, axis=0) / ENSEMBLE_AVG_COUNT,
        np.sum(models_attention_weights, axis=0) / ENSEMBLE_AVG_COUNT,
    )

def plot(data, labels, bag_class, predictions=None, attention_weights=None):

    """"Utility for plotting bags and attention weights.

    Args:
      data: Input data that contains the bags of instances.
      labels: The associated bag labels of the input data.
      bag_class: String name of the desired bag class.
        The options are: "positive" or "negative".
      predictions: Class labels model predictions.
      If you don't specify anything, ground truth labels will be used.
      attention_weights: Attention weights for each instance within the input data.
      If you don't specify anything, the values won't be displayed.
    """

    labels = np.array(labels).reshape(-1)

    if bag_class == "positive":
        if predictions is not None:
            labels = np.where(predictions.argmax(1) == 1)[0]
        else:
            labels = np.where(labels == 1)[0]
            
        random_labels = np.random.choice(labels, PLOT_SIZE)
        bags = np.array(data)[:, random_labels]

    elif bag_class == "negative":
        if predictions is not None:
            labels = np.where(predictions.argmax(1) == 0)[0]
        else:
            labels = np.where(labels == 0)[0]

        random_labels = np.random.choice(labels, PLOT_SIZE)
        bags = np.array(data)[:, random_labels]

    else:
        print(f"There is no class {bag_class}")
        return

    print(f"The bag class label is {bag_class}")
    for i in range(PLOT_SIZE):
        figure = plt.figure(figsize=(8, 8)) #each image
        print(f"Bag number: {labels[i]}")
        for j in range(BAG_SIZE):
            image = bags[j][i]
            figure.add_subplot(1, BAG_SIZE, j + 1)
            plt.grid(False)
            plt.axis('off')
            if attention_weights is not None:
                plt.title(np.around(attention_weights[random_labels[i]][j], 2))
            plt.imshow(image)
        plt.show()
    return figure


# Evaluate and predict classes and attention scores on validation data.
def predict_and_plot(class_):
    print('WTF')
    class_predictions, attention_params = predict(val_data, val_labels, trained_models)
    PLOT_SIZE = 1
    return plot(val_data, val_labels, class_,
                predictions=class_predictions,
                attention_weights=attention_params)
    
predict_and_plot('positive')

inputs = gr.Radio(choices=['positive','negative'])

outputs = gr.Plot(label='predicted bag')

#title = "Heart Disease Classification 🩺❤️"
#description =  "Binary classification of structured data including numerical and categorical features."
#article = "Author: <a href=\"https://huggingface.co/buio\">Marco Buiani</a>. Based on the <a href=\"https://keras.io/examples/structured_data/structured_data_classification_from_scratch/\">keras example</a> by <a href=\"https://twitter.com/fchollet\">François Chollet</a> Model Link: https://huggingface.co/buio/structured-data-classification"

demo = gr.Interface(fn=predict_and_plot, inputs=inputs, outputs=outputs, title=title, allow_flagging='never')

demo.launch(debug=True)