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klips/python/neural-network/neural-network.py

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Add Python project examples + Neural network CLI + Hidden Markov Model CLI + K-Means clustering CLI + Linear regression CLI + Screenshots, updated README instructions
2022-02-06 18:39:26 +00:00
################################################################################
# Author: Shaun Reed #
# About: ANN implementation with adjustable layers and layer lengths #
# Contact: shaunrd0@gmail.com | URL: www.shaunreed.com | GitHub: shaunrd0 #
################################################################################
from matplotlib import pyplot as plt
from sklearn.datasets import load_iris
from typing import List
import argparse
import json
import math
import numpy as np
import pandas as pd # Unused unless optional code is manually uncommented
import random
import sys
import viznet as vn
################################################################################
# CLI Argument Parser
################################################################################
# ==============================================================================
def init_parser():
parser = argparse.ArgumentParser(
description='Neural network implementation',
formatter_class=argparse.RawTextHelpFormatter
)
parser.add_argument(
'inputs', metavar='INPUTS', type=int, nargs='?',
help=
'''Number of inputs for the neural network
(default: '%(default)s')
''',
default=3
)
parser.add_argument(
'perceptrons', metavar='PERCEPTRONS', type=int, nargs='?',
help=
'''Number of perceptrons in each hidden layer
(default: '%(default)s')
''',
default=8
)
parser.add_argument(
'outputs', metavar='OUTPUTS', type=int, nargs='?',
help=
'''Number of outputs for the neural network
(default: '%(default)s')
''',
default=3
)
parser.add_argument(
'--hidden-layers', '-l', metavar='HIDDEN_LAYERS', type=int, nargs='?',
help=
'''Number of hidden layers
(default: '%(default)s')
''',
default=1
)
parser.add_argument(
'--cycles', '-c', metavar='CYCLES', type=int, nargs='?',
help=
'''Number of cycles to run through the network
(default: '%(default)s')
''',
default=3
)
parser.add_argument(
'--learn-rate', metavar='LEARNING_RATE', type=float, nargs='?',
help=
'''Learning rate to use for the network.
Must be within range of 0.0 < rate <= 1.0
(default: '%(default)s')
''',
default=0.25
)
parser.add_argument(
'--bias', '-b', metavar='INITIAL_BIAS', type=float, nargs='?',
help=
'''The initial bias to use for perceptrons within the network.
Must be within range of -1.0 <= bias <= 1.0
If value is unset, bias will be initialized randomly
''',
)
parser.add_argument(
'--weight', '-w', metavar='INITIAL_EDGE_WEIGHTS', type=float, nargs='?',
help=
'''The initial edge weight to use for node connections in the network
If value is unset, edge weights will be initialized randomly
'''
)
parser.add_argument(
'--error-threshold', '--error', metavar='ERROR_THRESHOLD', type=float, nargs='?',
help=
'''The acceptable error threshold to use for training the network.
(default: '%(default)s')
''',
default=0.5
)
parser.add_argument(
'--fire-threshold', '--fire', metavar='FIRE_THRESHOLD', type=float, nargs='?',
help=
'''The fire threshold for perceptrons in the network.
If a perceptron\'s cumulative inputs reach this value, the perceptron fires
(default: '%(default)s')
''',
default=0.25
)
parser.add_argument(
'--spacing', metavar='LAYER_SPACING', type=float, nargs='?',
help=
'''Distance between origin of network layers within visualization
(default: '%(default)s')
''',
default=2.0
)
parser.add_argument(
'--horizontal', '--flip', action='store_true',
help=
'''The network visualization will flow left-to-right
(default: '%(default)s')
''',
default=False
)
parser.add_argument(
'--silent', action='store_true',
help=
'''Do not show the network visualization, only print output to console
(default: '%(default)s')
''',
default=False
)
parser.add_argument(
'--verbose', '-v', action='store_true',
help=
'''When this flag is set, error rate and change in weight will be output for each calculation
(default: '%(default)s')
''',
default=False
)
parser.add_argument(
'--file', '-f', metavar='file_path', nargs='?', type=open,
help=
'''Optionally provide a json file to configure any option available through the cli
json keys match --long version of each option, where --long-split option key is "long_split" in json
''',
)
return parser
################################################################################
# Neural Network
################################################################################
# ==============================================================================
def parse_file():
"""
Validates keys in JSON file and updates CLI input context
:return: (seq_input, seq_label) Initialized to input and label sequences in JSON file if present
"""
# Load the JSON input file, validate keys
file_data = json.load(context['file'])
for key in file_data:
if key == "input_sequence" or key == "label_sequence":
continue
assert key in context
# Update the CLI context with JSON input
context.update(file_data)
# If JSON file provided input and label sequences, load and return them
seq_input = seq_label = None
if 'input_sequence' in file_data:
seq_input = np.array(file_data['input_sequence'])
if 'label_sequence' in file_data:
seq_label = np.array(file_data['label_sequence'])
return seq_input, seq_label
def network_layers():
"""
Initialize a dictionary of layers where each layer is a list of nodes: {'input': [0, 1, 2]}
The hidden layer in this dictionary is a list of lists for each hidden layer: {'hidden': [[3, 4, 5], [6, 7, 8]]}
:return: A dictionary, as an example: {'input': [0, 1, 2], 'hidden': [[3, 4, 5], [6, 7, 8]], 'output': [9, 10, 11] }
"""
inputs = [i for i in range(context["inputs"])]
offset = context["inputs"]
# For each hidden layer add the requested number of perceptrons
hidden = [[] for x in range(context["hidden_layers"])]
for x in range(context["hidden_layers"]):
hidden[x] = [i for i in range(offset, context["perceptrons"] + offset)]
offset += context["perceptrons"]
outputs = [i for i in range(offset, context["outputs"] + offset)]
offset += context["outputs"]
layers = {"inputs": inputs, "hidden": hidden, "outputs": outputs}
[print(f'{layer} layer: {layers[layer]}') for layer in layers]
return layers
def random_matrix(rows, cols, low=-1.0, high=1.0):
""" Produce a random matrix of size ROWSxCOLS using LOW and HIGH as upper and lower bounds """
return np.random.uniform(low, high, (rows, cols))
def get_matrix_dict():
"""
Produces a dictionary that holds edge weight transition matrices for each layer of the network
matrix_dict['input'] maps to a single 2D matrix
matrix_dict['hidden'] maps to a 3D matrix
+ where matrix_dict['hidden'][0] is the 2D transition matrix for the first hidden layer
:return: A dictionary, as an example: {'input': [[...]], 'hidden': [[[...]], [[...]]], 'output': [[...]] }
"""
if context["weight"] is None:
# Create matrices to represent edges and weights for each layer of the network
input_matrix = random_matrix(context["inputs"], context["perceptrons"])
hidden_matrices = [random_matrix(context["perceptrons"], context["perceptrons"])
for x in range(context["hidden_layers"]-1)]
output_matrix = random_matrix(context["perceptrons"], context["outputs"])
else:
# If an initial edge weight was specified, fill matrices with that value instead of generating randomly
input_matrix = np.full((context["inputs"], context["perceptrons"]), context["weight"])
hidden_matrices = [np.full((context["perceptrons"], context["perceptrons"]), context["weight"])
for x in range(context["hidden_layers"]-1)]
output_matrix = np.full((context["perceptrons"], context["outputs"]), context["weight"])
matrix_dict = {'input': input_matrix, 'hidden': np.array(hidden_matrices), 'output': output_matrix}
return matrix_dict
def get_bias_dict():
"""
Produces a dictionary that stores bias vectors for perceptrons in each layer of the network
The hidden layer in this dictionary is a list of lists for bias in each hidden layer: {'hidden': [[...], [...]]}
:return: A dictionary, as an example: {'input': [0.5, 0.5], 'hidden': [[0.5, 0.5 0.5], ...], 'output': [...] }
"""
# If there was a bias provided, use it; Else use random perceptron bias
bias = round(random.uniform(-1.0, 1.0), 2) if context["bias"] is None else context["bias"]
# Create vectors to represent perceptron bias in each layer
input_bias = [bias for x in range(0, context["inputs"])]
hidden_bias = [[bias for x in range(0, context["perceptrons"])] for x in range(0, context["hidden_layers"])]
output_bias = [bias for x in range(0, context["outputs"])]
bias_dict = {'input': input_bias, 'hidden': hidden_bias, 'output': output_bias}
return bias_dict
def threshold_fire(input_sum):
"""
Applies step function using fire_threshold set by CLI to determine if perceptron is firing or not
:param input_sum: The sum of inputs for this perceptron
:return: A list of outputs for each perceptron in the layer. If only the first fired: [1, 0, 0, 0]
"""
output = [1 if val > context["fire_threshold"] else 0 for val in input_sum.tolist()]
return output
def adjust_weight(matrix_dict, out_output, label):
"""
Back propagation for adjusting edge weights of nodes that produces incorrect output
:param matrix_dict: A dictionary of matrices for the network produces by get_matrix_dict()
:param out_output: The actual output for this input sequence
:param label: The desired result for this input sequence
:return: A dictionary of transition matrices for the network with adjusted edge weights
"""
# Find erroneous indices
bad_nodes = error_nodes(out_output, label)
if len(bad_nodes) == 0:
return matrix_dict
# Adjust the edge weights leading to the error nodes; Don't adjust correct nodes
for layer, mat in reversed(matrix_dict.items()):
if layer == 'output':
for node in bad_nodes:
for row in range(len(mat)):
mod = context['learn_rate'] * (label[node] - out_output[node]) # * Input (???)
if context['verbose']:
print(f'Adjusting output weights at ({row}, {node}) with {mod}')
mat[row][node] += mod
# In a fully connected neural network, all edges are updated if any output node is wrong
# + Every node of every layer connects to every node in the next layer
# + Any wrong node updates all edges in previous layers
if layer == 'hidden':
# If there are any hidden layers that do not connect to input or output layers directly
if mat.size > 0:
# For each hidden layer matrix, update all edge weights
for i, hl_mat in enumerate(mat):
for row in range(len(hl_mat)):
mod = context['learn_rate']
for col in range(len(hl_mat[row])):
# print(f'Adjusting output weights at ({row}, {col}) with {mod}')
mat[i][row][col] += context["learn_rate"]
if layer == 'input':
for row in range(len(mat)):
mod = context['learn_rate']
for col in range(len(mat[row])):
# print(f'Adjusting output weights at ({row}, {col}) with {mod}')
mat[row][col] += mod
return matrix_dict
def error_rate(actual_output, label):
"""
Determines error rate for this input sequence
Error rate is later used to determine if edge weights should be adjusted
:param actual_output: The actual output for this input sequence
:param label: The desired output for this input sequence
:return: The error rate for the sequence
"""
error_sum = 0
for n, output in enumerate(actual_output):
err = label[n] - output
error_sum += math.pow(err, 2)
err = math.sqrt(error_sum)
return err
def error_nodes(out_output, label):
"""
Find which output nodes are incorrect
:param out_output: Actual output for this input sequence
:param label: The desired output for this input sequence
:return: A list of node indices that produced the wrong output for this sequence
"""
# Loop through each output, check if it matches the label; If it doesn't add index to returned list
return [i for i, output in enumerate(out_output) if output != label[i]]
def layer_pass(weight_matrix, input_vector, bias_vector):
"""
Passes input from layer A to layer B
:param weight_matrix: Transition matrix of edge weights where perceptrons from layer A are rows and B are columns
:param input_vector: An input vector that represents the output from A to B
:param bias_vector: The bias vector for perceptrons in layer B
:return: Final output from the layer, after step function is applied in threshold_fire()
"""
layer_edge_weights = np.array(weight_matrix).T
prev_output = np.atleast_2d(input_vector).T
this_layer_input = layer_edge_weights.dot(prev_output).T.flatten()
this_layer_input += np.array(bias_vector)
return threshold_fire(this_layer_input)
def train_network(seq_input, seq_label, bias_dict, matrix_dict):
"""
Performs forward pass through network, moving through the number of cycles requested by the CLI
:param seq_input: Sequence of inputs to feed into the network
:param seq_label: Sequence of labels to verify network output and indicate error
:param bias_dict: Dictionary of bias vectors for the perceptrons in each layer
:param matrix_dict: Dictionary of transition matrices for the edge weights between layers in the network
:return: Information gathered from training the network used to output final accuracy
"""
# Info dictionary used to track accuracy
info = {'correct': 0, 'wrong': 0, 'total': len(seq_input) * context["cycles"], 'first_acc': 0}
# A list of error rates for each cycle
# + These aren't used much for the program, but they hold nice data to explore while debugging
cycle_errors = []
cycle_outputs = [[] for x in range(context["cycles"])]
for cycle_index in range(1, context["cycles"] + 1):
# print(f'\nCycle number {cycle_index}')
for seq_index in range(0, len(seq_input)):
# One list for storing the outputs of each layer, and another to store inputs
seq_outputs = []
# Input layer -> Hidden layer
# Apply input perceptron bias vector to initial inputs of the input layer
in_input = np.array(np.array(seq_input[seq_index]) + np.array(bias_dict['input']))
# Find output of the input layer
in_output = threshold_fire(in_input)
seq_outputs.append(in_output)
# Find output for first hidden layer
hl_output = layer_pass(matrix_dict["input"], seq_outputs[-1], bias_dict['hidden'][0])
seq_outputs.append(hl_output)
# For each hidden layer find inputs and outputs, up until the last hidden layer
# + Start at 1 since we already have the output from first hidden layer
for layer_index in range(1, context["hidden_layers"]):
# Hidden layer -> Hidden layer
edges = matrix_dict['hidden'][layer_index - 1]
bias = bias_dict['hidden'][layer_index - 1]
# Find output for hidden layer N
hl_output = layer_pass(edges, seq_outputs[-1], bias)
seq_outputs.append(hl_output)
# Hidden layer -> Output layer
# Find output for output layer
out_output = layer_pass(matrix_dict['output'], seq_outputs[-1], bias_dict['output'])
seq_outputs.append(out_output)
# Forward pass through network finished
# Find error rate for this input sequence
err = error_rate(out_output, seq_label[seq_index])
if context['verbose'] and err > 0:
print(f'Error rate for sequence {seq_index} cycle {cycle_index}: {err}')
# If error rate for this sequence is above threshold, adjust weighted edges
if err > context["error_threshold"]:
matrix_dict = adjust_weight(matrix_dict, out_output, seq_label[seq_index])
# Track correctness of sequences and cycles
if err == 0:
info['correct'] += 1
else:
info['wrong'] += 1
# Append the result to the cycle_outputs list for this cycle; -1 for 0 index array offset
# cycle_outputs contains a list for each cycle. Each list contains N outputs for N input sequences
cycle_outputs[cycle_index - 1].append(out_output)
cycle_errors.append(err)
# Move to next learning cycle in for loop
info_total_temp = info['correct'] + info['wrong']
if cycle_index == 1:
info['first_acc'] = round(100.0 * float(info["correct"] / info_total_temp), 4)
print(
f'[Cycle {cycle_index}] \tAccuracy: {100.0 * float(info["correct"] / info_total_temp):.4f}% \t'
f'[{info["correct"]} / {info["wrong"]}]'
)
if context["verbose"]:
for layer in matrix_dict:
print(
f'Network {layer} layer: \n{matrix_dict[layer]}\n'
# Bias vector doesn't change, so it's not very interesting output per-cycle
# f'{layer} bias vector: {bias_dict[layer]}'
)
info['cycle_error'] = cycle_errors
return info
def draw_graph(net_plot, net_layers, draw_horizontal=None, spacing=None):
"""
This is the only function where viznet is used. Viznet is a module to visualize network graphs using matplotlib.
https://viznet.readthedocs.io/en/latest/core.html
https://viznet.readthedocs.io/en/latest/examples.html#examples
To draw the graph, we need to at least specify the following information for-each layer in the network -
1. The number of nodes in the layer
2. The type of nodes that make up each layer (https://viznet.readthedocs.io/en/latest/viznet.theme.html)
3. The distance between the center (origin) of each layer
With this we can use viznet helper functions to draw network
:param net_plot: A matplotlib subplot to draw the network on
:param net_layers: A dictionary of layers that make up the network nodes
:param draw_horizontal: True if graph should be drawn so direction flows left->right; False for bottom->top
:param spacing: The distance between the center of origin for each layer in the network
"""
# If no spacing was provided to the call, use spacing set by CLI
spacing = context["spacing"] if spacing is None else spacing
# If no draw mode was provided to the call, use mode set by CLI
draw_horizontal = context["horizontal"] if draw_horizontal is None else draw_horizontal
# 1. Number of nodes in each layer is provided by dictionary: len(net_layers['input'])
# 2. Define node type to draw for each layer in the network (default ['nn.input', 'nn.hidden', nn.output])
node_types = ['nn.input'] + ['nn.hidden'] * context["hidden_layers"] + ['nn.output']
# 3. Use spacing distance to create list of X positions with equal distance apart (default [0, 1.5, 3.0])
# 1.5 * 0 = 0; 1.5 * 1 = 1.5; 1.5 * 2 = 3.0; 1.5 * 3 = 4.5; etc
layer_pos = spacing * np.arange(context["hidden_layers"] + 2)
# Create a sequence of Node objects using viznet helper function node_sequence
# + Allows defining a NodeBrush for-each node, which is used by the library to style nodes
node_sequence = []
layer_index = 0
for layer in net_layers:
# If we are on the hidden layers, iterate through each
if layer == 'hidden':
for hl in net_layers[layer]:
brush = vn.NodeBrush(node_types[layer_index], net_plot)
ctr = (layer_pos[layer_index], 0) if draw_horizontal else (0, layer_pos[layer_index])
node_sequence.append(vn.node_sequence(
brush, len(hl),
center=ctr, space=(0, 1) if draw_horizontal else (1, 0))
)
layer_index += 1
else:
brush = vn.NodeBrush(node_types[layer_index], net_plot)
ctr = (layer_pos[layer_index], 0) if draw_horizontal else (0, layer_pos[layer_index])
node_sequence.append(vn.node_sequence(
brush, len(net_layers[layer]),
center=ctr, space=(0, 1) if draw_horizontal else (1, 0))
)
layer_index += 1
# Define an EdgeBrush that draws arrows between nodes using matplotlib axes
edge_brush = vn.EdgeBrush('-->', net_plot)
for start, end in zip(node_sequence[:-1], node_sequence[1:]):
# Connect each node in `start` layer to each node in `end` layer
for start_node in start:
for end_node in end:
# Apply the EdgeBrush using matplotlib axes and node edge tuple
edge_brush >> (start_node, end_node)
plt.show()
################################################################################
# Main
################################################################################
# ==============================================================================
def main(args: List[str]):
parser = init_parser()
global context
context = vars(parser.parse_args(args[1:]))
seq_input = None
seq_label = None
if context['file']:
seq_input, seq_label = parse_file()
if seq_input is None or seq_label is None:
# You cannot provide input or label sequences via the CLI
# If no file was provided with data, use iris dataset as example data
# Use sklearn.dataset to grab example data
iris = load_iris()
# iris_data = iris.data[:, (0, 1, 2, 3)]
iris_data = iris.data[:, (0, 2, 3)]
# iris_data = iris.data[:, (2, 3)]
iris_label = iris.target
# Or read a CSV manually using pandas
# iris = pd.read_csv('/home/kapper/Code/School/CS/AI/Assignment/two/IRIS.csv').to_dict()
# iris_data = [[x, y] for x, y in zip(iris['petal_length'].values(), iris['petal_width'].values())]
# iris_data = [[x, y, z] for x, y, z in zip(iris['petal_length'].values(),
# iris['petal_width'].values(),
# iris['sepal_length'].values())]
# iris_label = [x for x in iris['species'].values()]
# To change the number of output nodes, we need to adjust the number of labels for classification
# iris_data = iris.data[0:99, (0, 2, 3)]
# iris_label = [l for l in iris_label if l != 2]
# Convert labels to: 0-> [1, 0, 0]; 1-> [0, 1, 0]; 2->[0, 0, 1]
seq_input = iris_data
seq_label = []
for i, label in enumerate(set(iris_label)):
same = [s for s in iris_label if s == label]
for l in same:
new_label = np.zeros(len(set(iris_label))).tolist()
new_label[i] = 1
seq_label.append(new_label)
# Assert that the provided learning rate is valid
assert(0.0 < context['learn_rate'] <= 1.0)
# This check ensures that the number of inputs match the number of input nodes
# + And does the same for output nodes with possible classifications
# + But, this removes the ability to grow / shrink input / output layers through CLI
if context["inputs"] != len(seq_input[0]):
print(f'Warning: Input sequences each contain {len(seq_input[0])} entries '
f'but {context["inputs"]} input nodes were requested.\n'
f'\tUsing {len(seq_input[0])} input nodes instead of {context["inputs"]}'
)
context["inputs"] = len(seq_input[0])
if context["outputs"] != len(set(map(tuple, seq_label))):
print(f'Warning: Output labels contain {len(set(map(tuple, seq_label)))} possible classifications '
f'but {context["outputs"]} output were nodes requested.\n'
f'\tUsing {len(set(map(tuple, seq_label)))} output nodes instead of {context["outputs"]}'
)
context["outputs"] = len(set(map(tuple, seq_label)))
# Output the problem settings
print(f'Creating a single layer neural network: \n'
f'\tTotal input nodes: {context["inputs"]}\n'
f'\tNumber of perceptrons in each hidden layer: {context["perceptrons"]}\n'
f'\tTotal output nodes: {context["outputs"]}\n'
f'\tNumber of hidden layers: {context["hidden_layers"]}\n'
f'\tFire threshold: {context["fire_threshold"]}\n'
f'\tError threshold: {context["error_threshold"]}\n'
f'\tLearn rate: {context["learn_rate"]}\n'
f'\tInitial bias: {context["bias"] if context["bias"] is not None else "Random"}\n'
f'\tInitial edge weights: {context["weight"] if context["weight"] is not None else "Random"}\n'
f'Network visualization settings: \n'
f'\tGraph visualization is enabled: {not context["silent"]}\n'
f'\tGraph visualization is horizontal: {context["horizontal"]}\n'
f'\tGraph visualization is vertical: {not context["horizontal"]}\n'
f'\tGraph visualization layer spacing: {context["spacing"]}\n'
f'\tTest data input count: {len(seq_input)}'
)
# Initialize a dictionary of vectors for mapping to each layer node
# + layers['hidden'][0] = [3, 4, 5, 6] --> Hidden layer nodes are at index 3, 4, 5, 6
layers = network_layers()
# A dictionary where matrix_dict['input'] maps to edge weight matrix for input_layer->first_hidden_layer
# matrix_dict['hidden'] maps to a list of matrices; matrix_dict['hidden'][0] is edge weights for first_hl->second_hl
# matrix_dict['output'] maps to edge weight matrix for last_hl->output_layer
matrix_dict = get_matrix_dict()
# Randomly generate perceptron bias if none was provided through CLI
bias_dict = get_bias_dict()
info = train_network(seq_input, seq_label, bias_dict, matrix_dict)
# Final console output for overall results
info_total_temp = info['correct'] + info['wrong']
acc = 100.0 * float(info["correct"] / info_total_temp)
print(
f'\nCorrect: {info["correct"]} \t Wrong: {info["wrong"]} \t Total: {context["cycles"] * len(seq_input)}'
f'\nCycle 1 accuracy: {info["first_acc"]}% \tCycle {context["cycles"]} accuracy: {acc:.4f}%'
f'\n{round(acc - info["first_acc"], 4)}% change over {context["cycles"]} cycles '
f'\t{round((acc - info["first_acc"]) / context["cycles"], 4)}% average change per cycle'
)
# All cycles have finished; Draw the network for a visual example to go with output
if not context["silent"]:
draw_graph(plt.subplot(), layers)
if __name__ == "__main__":
sys.exit(main(sys.argv))