dl_basics_utilities.py

'''
Copyright (c) 2017-21 Andrew Glassner

Permission is hereby granted, free of charge, to any person obtaining a copy 
of this software and #associated documentation files (the "Software"), to deal i
n the Software without restriction, including #without limitation the rights to 
use, copy, modify, merge, publish, distribute, sublicense, and/or sell #copies 
of the Software, and to permit persons to whom the Software is furnished to do 
so, subject to the #following conditions:

The above copyright notice and this permission notice shall be included in all 
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A 
PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT 
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Deep Learning: A Visual Approach
by Andrew Glassner, https://glassner.com
Order: https://nostarch.com/deep-learning-visual-approach
GitHub: https://github.com/blueberrymusic
'''

# 
# -----------------------------------------------------------------------------
# 

import os
import matplotlib.pyplot as plt
import numpy as np
import h5py
from keras.models import load_model

class File_Helper:

	"""
	These routines let us conveniently save and load input data, such
	as text and image files, as well as save and load Keras model files
	and weight files.  When we save a file, the corresponding directory 
	is created if necessary. 
	
	When we make the object, we can optionally set the one argument really_save_files
	to True or False, depending on whether or not we want save_xx() calls to really
	write files. It's time-saving to set this to False when debugging because writing
	files can take a while. The default value is True.
	
	Here's a typical way to import this package from a file in a folder two levels down
	(adapted from https://stackoverflow.com/questions/714063/importing-modules-from-parent-folder)
	
	# find the absolute path to the parent folder and add that to Python's search list
	import os, sys, inspect
	current_dir = os.path.dirname(os.path.abspath(inspect.getfile(inspect.currentframe())))
	sys.path.insert(0, os.path.dirname(current_dir)) # path to grandparent dir
	# Now that we can find the folder, import the package and instantiate a File_Helper object
	from Python_Utilities import File_Helper
	file_helper = File_Helper(True)  
	"""
	
	def __init__(self, really_save_files=True):
		self.really_save_files = really_save_files
		self.saved_output_dir = 'saved_output'
		self.input_data_dir = 'input_data'
		self.saved_models_dir = 'saved_models'
		self.saved_weights_dir = 'saved_weights'

	def get_input_file_path(self, filename):
		"""Get the local path relative to the calling file's location to the input file"""
		return self.input_data_dir + '/' + filename
	
	def check_for_directory(self, directory, create_if_needed=True):
		"""See if the directory exists. Optionally, create it."""
		path_exists = os.path.exists(directory)
		if path_exists:
			if not os.path.isdir(directory):
				raise Exception('Found '+directory+' but it is a file, not a directory')
				return False
			return True
		if create_if_needed:
			os.makedirs(directory)
		return path_exists

	def save_figure(self, filename):
		"""Save the figure. Call this just before plt.show()."""
		if self.really_save_files and (filename != None):
			self.check_for_directory(self.saved_output_dir)
			plt.savefig(self.saved_output_dir+'/'+filename+'.png', dpi=300, bbox_inches='tight')

	def load_model_weights(self, model, weights_filename):
		"""If the weights file exists, load from it and return True, else return False."""
		fullpath = self.saved_weights_dir+'/'+weights_filename+'.h5'
		if os.path.exists(fullpath):
			if os.path.isfile(fullpath):
				model.load_weights(fullpath)
				return True
		return False

	def save_model_weights(self, model, weights_filename):
		"""Save the weights file in the saved weights directory."""
		if self.really_save_files and (weights_filename != None):
			self.check_for_directory(self.saved_weights_dir)
			fullpath = self.saved_weights_dir+'/'+weights_filename+'.h5'
			model.save_weights(fullpath)

	def load_model(self, model_filename):
		"""If the model file exists, load from it and return the model, else return None."""
		fullpath = self.saved_models_dir+'/'+model_filename+'.h5'
		if os.path.exists(fullpath):
			if os.path.isfile(fullpath):
				model = load_model(fullpath)
				return model
		return None

	def save_model(self, model, model_filename):
		"""Save the model file in the saved models directory."""
		if self.really_save_files and (model_filename != None):
			self.check_for_directory(self.saved_models_dir)
			fullpath = self.saved_models_dir+'/'+model_filename+'.h5'
			model.save(fullpath)

	def get_saved_output_dir(self):
		"""Get the name of the directory where we save matplotlib output PNG files."""
		return self.saved_output_dir
	
	def get_input_data_dir(self):
		"""Get the name of the directory where we look for input files."""
		return self.input_data_dir
	
	def get_saved_weights_dir(self):
		"""Get the name of the directory where we read and write Keras weight files."""
		return self.saved_weights_dir
	
	def get_saved_models_dir(self):
		"""Get the name of the directory where we read and write Keras model files."""
		return self.saved_models_dir