data_logging_utils.py

"""Data Logging Functions

Description:

    This folder contains several functions which, either on their own or included in larger pieces of software, perform data logging tasks.

Usage:

    To use content from this folder, import the functions and instantiate them as you wish to use them:

        from utils.data_logging_utils import function_name

"""

import os
import matplotlib
import matplotlib.pyplot as plt
import shutil
import logging
import numpy as np
import re
from textwrap import wrap
import torch

# The SummaryWriter class provides a high-level API to create an event file in a given directory and add summaries and events to it.
# More here: https://tensorboardx.readthedocs.io/en/latest/tensorboard.html
from tensorboardX import SummaryWriter

import utils.data_evaluation_utils as evaluation

plt.axis('scaled')


class LogWriter():

    """Log Writer class for the BrainMapper U-net.

    This class contains the pytorch implementation of the several logging functions required for the BrainMapper project.
    These functions are designed to keep track of progress during training, and also aid debugging.

    Args:
        number_of_classes (int): Number of classes
        logs_directory (str): Directory for outputing training logs
        experiment_name (str): Name of the experiment
        use_last_checkpoint (bool): Flag for loading the previous checkpoint
        labels (arr): Vector/Array of labels (if applicable)
        confusion_matrix_cmap (class): Colour Map to be used for the Conusion Matrix
    """

    def __init__(self, number_of_classes, logs_directory, experiment_name, use_last_checkpoint=False, labels=None, confusion_matrix_cmap=plt.cm.Blues):

        self.number_of_classes = number_of_classes
        training_logs_directory = os.path.join(
            logs_directory, experiment_name, "train")
        testing_logs_directory = os.path.join(
            logs_directory, experiment_name, "test")

        # If the logs directory exist, we clear their contents to allow new logs to be created
        if not use_last_checkpoint:
            if os.path.exists(training_logs_directory):
                shutil.rmtree(training_logs_directory)
            if os.path.exists(testing_logs_directory):
                shutil.rmtree(testing_logs_directory)

        self.log_writer = {
            'train': SummaryWriter(logdir=training_logs_directory),
            'test:': SummaryWriter(logdir=testing_logs_directory)
        }

        self.confusion_matrix_color_map = confusion_matrix_cmap

        self.current_iteration = 1

        if labels is not None:
            self.labels = self.labels_generator(labels)
        else:
            pass

        self.logger = logging.getLogger()
        file_handler = logging.FileHandler(
            "{}/{}.log".format(os.path.join(logs_directory, experiment_name), "console_logs"))
        self.logger.addHandler(file_handler)

    def labels_generator(self, labels):
        """ Label Generator Function

        This function processess an input array of labels.

        Args:
            labels (arr): Vector/Array of labels (if applicable)

        Returns:
            label_classes (list): List of processed labels
        """

        label_classes = []

        for label in labels:

            label_class = re.sub(
                r'([a-z](?=[A-Z])|[A-Z](?=[A-Z][a-z]))', r'\1 ', label)
            label_class = ['\n'.join(wrap(element, 40))
                           for element in label_class]
            label_classes.append(label_class)

        return label_classes

    def log(self, message):
        """Log function

        This function logs a message in the logger.

        Args:
            message (str): Message to be logged
        """

        self.logger.info(msg=message)

    def loss_per_iteration(self, loss_per_iteration, batch_index, iteration):
        """Log of loss / iteration

        This function records the loss for every iteration.

        Args:
            loss_per_iteration (torch.tensor): Value of loss for every iteration step
            batch_index (int): Index of current batch
            iteration (int): Current iteration value
        """

        print("Loss for Iteration {} is: {}".format(
            batch_index, loss_per_iteration))
        self.log_writer['train'].add_scalar(
            'loss / iteration', loss_per_iteration, iteration)

    def loss_per_epoch(self, losses, phase, epoch):
        """Log function

        This function records the loss for every epoch.

        Args:
            losses (list): Values of all the losses recorded during the training epoch
            phase (str): Current run mode or phase
            epoch (int): Current epoch value
        """

        if phase == 'train':
            loss = losses[-1]
        else:
            loss = np.mean(losses)

        print("Loss for Epoch {} of {} is: {}".format(epoch, phase, loss))
        self.log_writer[phase].add_scalar('loss / iteration', loss, epoch)

    # Currently, no confusion matrix is required
    # TODO: add a confusion matrix per epoch and confusion matrix plot functions if required

    def dice_score_per_epoch(self, phase, outputs, correct_labels, epoch):
        """Function calculating dice score for each epoch

        This function computes the dice score for each epoch.

        Args:
            phase (str): Current run mode or phase
            outputs (torch.tensor): Tensor of all the network outputs (Y-hat)
            correct_labels (torch.tensor): Output ground-truth labelled data (Y)
            epoch (int): Current epoch value
        """

        print("Dice Score is being calculated...", end='', flush=True)
        dice_score = evaluation.dice_score_calculator(
            outputs, correct_labels, self.number_of_classes)
        mean_dice_score = torch.mean(dice_score)
        self.plot_dice_score(
            dice_score, phase, plot_name='dice_score_per_epoch', title='Dice Score', epochs=epoch)
        print("Dice Score calculated successfully")
        return mean_dice_score.item()

    def plot_dice_score(self, dice_score, phase, plot_name, title, epochs=None):
        """Function plotting dice score for multiple epochs

        This function plots the dice score for each epoch.

        Args:
            dice_score (torch.tensor): Dice score value for each class
            phase (str): Current run mode or phase
            plot_name (str): Caption name for later refference
            title (str): Plot title
            epoch (int): Current epoch value
        """

        figure = matplotlib.figure.Figure()  # Might add some arguments here later
        ax = figure.add_subplot(1, 1, 1)
        ax.set_xlabel(title)
        ax.xaxis.set_label_position('top')
        ax.bar(np.arange(self.number_of_classes), dice_score)
        ax.set_xticks(np.arange(self.number_of_classes))
        ax.set_xticklabels(self.labels)
        ax.xaxis.tick_bottom()

        if epochs:
            self.log_writer[phase].add_figure(
                plot_name + '/' + phase, figure, global_step=epochs)
        else:
            self.log_writer[phase].add_figure(plot_name + '/' + phase, figure)

    # Currently, also no need for an evaluation box plot

    def sample_image_per_epoch(self, prediction, ground_truth, phase, epoch):
        """Function plotting mirrored images

        This function plots a predicted and a grond truth images side-by-side.

        Args:
            prediction (torch.tensor): Predicted image after passing throught the network
            ground_truth (torch.tensor): Labelled ground truth image
            phase (str): Current run mode or phase
            epoch (int): Current epoch value
        """

        print("Sample Image is being loaded...", end='', flush=True)
        figure, ax = plt.subplots(nrows=len(prediction), ncols=2)

        for i in range(len(prediction)):
            ax[i][0].imshow(prediction[i])
            ax[i][0].set_title("Predicted Image")
            ax[i][0].axis('off')

            ax[i][1].imshow(ground_truth[i])
            ax[i][1].set_title('Ground Truth Image')
            ax[i][1].axis('off')

        figure.set_tight_layout()
        self.log_writer[phase].add_figure(
            'sample_prediction/'+phase, figure, epoch)

        print("Sample Image successfully loaded!")

    def close(self):
        """Close the log writer

        This function closes the two log writers.
        """

        self.log_writer['train'].close()
        self.log_writer['test'].close()