image = china[150:220, 130:250]
height, width, channels = image.shape
image_grayscale = image.mean(axis=2).astype(np.float32)
images = image_grayscale.reshape(1, height, width, 1)
fmap = np.zeros(shape=(7, 7, 1, 2), dtype=np.float32)
fmap[:, 3, 0, 0] = 1
fmap[3, :, 0, 1] = 1
plot_image(fmap[:, :, 0, 0])
plt.show()
plot_image(fmap[:, :, 0, 1])
plt.show()
reset_graph()
X = tf.placeholder(tf.float32, shape=(None, height, width, 1))
feature_maps = tf.constant(fmap)
convolution = tf.nn.conv2d(X,
feature_maps,
strides=[1, 1, 1, 1],
padding="SAME")
# with tf.Session() as sess:
# output = convolution.eval(feed_dict={X: images})
#
# plot_image(images[0, :, :, 0])
# save_fig("china_original", tight_layout=False)
# plt.show()
print('slope: ' + str(slope))
print('y_intercept: ' + str(y_intercept))
best_fit = []
for i in x_vals:
best_fit.append(slope * i + y_intercept)
# Plot the results
plt.plot(x_vals, y_vals, 'o', label='Data')
plt.plot(x_vals, best_fit, 'r-', label='Best fit line', linewidth=3)
plt.legend(loc='upper left')
plt.show()
util.reset_graph()
A = tf.constant(np.column_stack((x_vals_column, ones_column)))
b = tf.constant(np.transpose(np.matrix(y_vals)))
with tf.Session() as sess:
tA_A = tf.matmul(tf.transpose(A), A)
L = tf.cholesky(tA_A)
tA_b = tf.matmul(tf.transpose(A), b)
sol1 = tf.matrix_solve(L, tA_b)
sol2 = tf.matrix_solve(tf.transpose(L), sol1)
solution_eval = sess.run(sol2)
# Extract coefficients
slope = solution_eval[0][0]
y_intercept = solution_eval[1][0]
def reg(loss_func='l2', learn_rate=0.01, max_iter=100, batch_size=32):
util.reset_graph()
with tf.Session() as sess:
x_data = tf.placeholder(shape=[None, 1], dtype=tf.float32)
y_target = tf.placeholder(shape=[None, 1], dtype=tf.float32)
A = tf.Variable(tf.random_normal(shape=[1, 1]))
b = tf.Variable(tf.random_normal(shape=[1, 1]))
# y = Ax + b
model_output = tf.add(tf.matmul(x_data, A), b)
if loss_func == 'l2':
loss = tf.reduce_mean(tf.square(y_target - model_output))
elif loss_func == 'l1':
loss = tf.reduce_mean(tf.abs(y_target - model_output))
elif loss_func == 'lasso':
lasso_param = tf.constant(0.9)
heavyside_step = tf.truediv(
1.,
tf.add(1.,
tf.exp(tf.multiply(-100., tf.subtract(A,
lasso_param)))))
regularization_param = tf.multiply(heavyside_step, 99.)
loss = tf.add(tf.reduce_mean(tf.square(y_target - model_output)),
regularization_param)
elif loss_func == 'ridge':
ridge_param = tf.constant(1.)
ridge_loss = tf.reduce_mean(tf.square(A))
loss = tf.expand_dims(
tf.add(tf.reduce_mean(tf.square(y_target - model_output)),
tf.multiply(ridge_param, ridge_loss)), 0)
my_opt = tf.train.GradientDescentOptimizer(learn_rate)
train_step = my_opt.minimize(loss)
init = tf.global_variables_initializer()
init.run()
loss_vec = []
for i in range(max_iter):
rand_index = np.random.choice(len(x_vals), size=batch_size)
rand_x = np.transpose([x_vals[rand_index]])
rand_y = np.transpose([y_vals[rand_index]])
sess.run(train_step, feed_dict={x_data: rand_x, y_target: rand_y})
temp_loss = sess.run(loss,
feed_dict={
x_data: rand_x,
y_target: rand_y
})
if loss_func == 'l1' or loss_func == 'l2':
loss_vec.append(temp_loss)
else:
loss_vec.append(temp_loss[0])
if (i + 1) % 50 == 0:
print('Step #' + str(i + 1) + ' A = ' + str(sess.run(A)) +
' b = ' + str(sess.run(b)))
print('Loss = ' + str(temp_loss))
[slope] = sess.run(A)
[y_intercept] = sess.run(b)
# Get best fit line
best_fit = []
for i in x_vals:
best_fit.append(slope * i + y_intercept)
# Plot the result
plt.plot(x_vals, y_vals, 'o', label='Data Points')
plt.plot(x_vals, best_fit, 'r-', label='Best fit line', linewidth=3)
plt.legend(loc='upper left')
plt.title('Sepal Length vs Pedal Width')
plt.xlabel('Pedal Width')
plt.ylabel('Sepal Length')
plt.show()
# Plot loss over time
plt.plot(loss_vec, 'k-')
plt.title('L2 Loss per Generation')
plt.xlabel('Generation')
plt.ylabel('L2 Loss')
plt.show()
