import numpy as np #22:00 in part #5
import nnfs
from nnfs.datasets import spiral_data # importing sprial data
#don't have to do this, can use what had in same line in p6 - don't import nnfs also
nnfs.init() #this is from his github/youtube channel
# it sets the random seed, sets the default datatype for numpy to use, has the dataset also
# importing data, 100 feature sets of 3 classes (3 different colors in spiral, go to
# https://www.youtube.com/watch?v=gmjzbpSVY1A&list=PLQVvvaa0QuDcjD5BAw2DxE6OF2tius3V3&index=5 for more info)
X, y = spiral_data(100, 3)
class Layer_Dense:
def __init__(self, n_inputs, n_neurons):
'''.randn(sample size of 4, number of neurons)
b/c e/a neuron has #weights = #inputs, coding for layer
.randn allows you to define the shape of the array
.randn generates random values using gaussian aka normal distribution bounded around 0
all random numbers gaussian distribution with shape of array
multiply by 0.1 because want all output-input values to be small
after many iterations large values increase exponentially if not multiply by 0.1
Don't have to transpose weight matrix if initialize weights by dimensions of inputs and neurons '''
self.weights = 0.1 * np.random.randn(n_inputs, n_neurons)
''' initializing all biases to zero, shape of array is 1 by number of neurons
because each neuron has one bias and coding for one layer
if all final outputs are zero, then initialize biases to non-zero value
First parameter of np.zeroes is a shape, so the shape is a tuple (1, n_neurons)'''
self.biases = np.zeros((1, n_neurons))
def forward(self, inputs):
# X, y = create_data (100, 3)
# plt.scatter (X[:, 0], X[:, 1])
# plt.show ()
# plt.scatter (X[:, 0], X[:, 1], c = y, cmap= 'brg')
# plt.show ()
# Actual Code ------------------------------------------------------------------------------------------------------------
import numpy as np
import nnfs
from nnfs.datasets import spiral_data
nnfs.init ()
X, y = spiral_data (100, 3) # 100 feature sets of 3 classes
class Layer_Dense:
def __init__(self, n_inputs, n_neurons):
"""
Constructor function for the class
Params:
n_inputs: size of the input layer coming in
n_neurons: how many neurons should this layer have
Outputs:
No outputs. Just set the weights and biases on a layer based on the params
"""
self.weights = 0.10 * np.random.randn(n_inputs, n_neurons) # Shape of weights (n_inputs, n_neurons)
self.biases = np.zeros ((1, n_neurons)) # Shape of baises (1, n_neurons)
import numpy as np
import nnfs
from nnfs.datasets import spiral_data
nnfs.init() # Sets random seed and default data type for numpy
# Has two features X and y
X, y = spiral_data(100, 3)
class LayerDense:
def __init__(self, n_inputs, n_neurons):
self.weights = np.random.randn(n_inputs, n_neurons)
self.biases = np.zeros((1, n_neurons)) # This is a tuple!
def forward(self, inputs):
self.output = np.dot(inputs, self.weights) + self.biases
class ActivationReLU:
def forward(self, inputs):
self.output = np.maximum(0, inputs)
layer1 = LayerDense(2, 5)
activation1 = ActivationReLU()
layer1.forward(X)
activation1.forward(layer1.output)
print(activation1.output)
[-0.5, 0.12, -0.33],
[-0.44, 0.73, -0.13]
]
biases2 = [-1, 2, -0.5]
layer1_outputs = np.dot(inputs, np.array(weights).T) + biases
layer2_outputs = np.dot(layer1_outputs, np.array(weights2).T) + biases2
print(layer2_outputs)
# This is so cool, I feel like a wizard.
'''
'''
# Page 63-65
from nnfs.datasets import spiral_data
nnfs.init()
X, y = spiral_data(samples=100, classes=3)
print(X)
print(y)
plt.scatter(X[:, 0], X[:, 1], c=y, cmap='brg')
plt.show()
'''
# Page 66-71
# Dense Layer (Fully Connected)
import numpy as np
import nnfs
from nnfs.datasets import spiral_data
nnfs.init() # setting random seed and default data type for numpy to use
# X = [[1, 2, 3, 2.5],
# [2.0, 5.0, -1.0, 2.0],
# [-1.5, 2.7, 3.3, -0.8]]
# X = [[1], [2]]
##################################
# Long version of softmax function
##################################
# layer_outputs = [4.8, 1.21, 2.385]
#
# E = 2.71828182846
#
# exp_values = []
# for output in layer_outputs:
# exp_values.append(E ** output)
# print('exponentiated values:')
# print(exp_values)
#
# norm_base = sum(exp_values) #sum all values
# norm_values = []
# for value in exp_values:
# norm_values.append(value/norm_base)
# print('normalized expinentiated values:')
# print(norm_values)
# CODE FOR A DENSE LAYER OF NEURONS CLASS USING NUMPY
# SANTIAGO GARCIA ARANGO
import numpy as np
import nnfs
import matplotlib.pyplot as plt
from nnfs.datasets import spiral_data
# Initialize Neural Networks From Scratch package for following the book
nnfs.init(dot_precision_workaround=True,
default_dtype='float32',
random_seed=0)
class DenseLayer:
"""
DenseLayer is a class to create and process generalized neuron layers.
:param n_inputs: number of inputs
:param n_neurons: number of neurons
"""
def __init__(self, n_inputs, n_neurons):
# Initialize main layer with random weights and zero vector for biases
self.weights = 0.01 * np.random.randn(n_inputs, n_neurons)
self.biases = np.zeros((1, n_neurons))
def forward(self, inputs):
# Apply main forward pass with
self.output = np.dot(inputs, self.weights) + self.biases
if __name__ == "__main__":
def main():
nnfs.init()
X, y = spiral_data(samples=1000, classes=3)
dense1 = Layer(2,
512,
weight_regularizer_l2=5e-4,
bias_regularizer_l2=5e-4)
activation1 = ReLU()
dense2 = Layer(512, 3)
cost_act = Soft_Ce()
optimizer = Adam(learning_rate=0.02, decay=5e-7)
for epoch in range(10001):
dense1.forwardProp(X)
activation1.forwardProp(dense1.output)
dense2.forwardProp(activation1.output)
data_cost = cost_act.forwardProp(dense2.output, y)
regularization_cost = \
cost_act.cost.regularization_cost(dense1) + \
cost_act.cost.regularization_cost(dense2)
cost = data_cost + regularization_cost
predictions = np.argmax(cost_act.output, axis=1)
if len(y.shape) == 2:
y = np.argmax(y, axis=1)
accuracy = np.mean(predictions == y)
if not epoch % 100:
print(f'epoch: {epoch}, ' + f'acc: {accuracy:.3f}, ' +
f'cost: {cost:.3f}, (' + f'data_cost: {data_cost:.3f}, ' +
f'reg_cost: {regularization_cost:.3f}), ' +
f'lr: {optimizer.curr_learning_rate}')
cost_act.backProp(cost_act.output, y)
dense2.backProp(cost_act.dinputs)
activation1.backProp(dense2.dinputs)
dense1.backProp(activation1.dinputs)
optimizer.pre_update_params()
optimizer.update_params(dense1)
optimizer.update_params(dense2)
optimizer.post_update_params()
X_test, y_test = spiral_data(samples=100, classes=3)
dense1.forwardProp(X_test)
activation1.forwardProp(dense1.output)
dense2.forwardProp(activation1.output)
cost = cost_act.forwardProp(dense2.output, y_test)
predictions = np.argmax(cost_act.output, axis=1)
if len(y.shape) == 2:
y_test = np.argmax(y_test, axis=1)
accuracy = np.mean(predictions == y_test)
print(f'validation, acc: {accuracy:.3f}, cost: {cost:.3f}')
