def main_quadratic():
np.seterr(divide='ignore')
# the hessian matrix of the quadratic function
Q = np.matrix('5 2; 2 2')
# the vector of linear coefficient of the quadratic function
v = np.matrix('21; 13')
A = np.matrix('2 1; 2 -5;-1 1')
b = np.matrix('8; 10; 3')
t = len( b )
func = lambda x, order: quadratic_log_barrier( Q, v, A, b, x, t, order )
# Start at (0,0)
initial_x = np.matrix('0.0; 0.0')
# Find the (1e-8)-suboptimal solution
eps = 1e-8
maximum_iterations = 65536
# Run the algorithms
x, values, runtimes, gd_xs = alg.gradient_descent( func, initial_x, eps, maximum_iterations, alg.backtracking_line_search )
x, values, runtimes, newton_xs = alg.newton( func, initial_x, eps, maximum_iterations, alg.backtracking_line_search )
# Draw contour plots
draw_contour( func, gd_xs, newton_xs, levels=np.arange(-300, 300, 10), x=np.arange(-4, 2.1, 0.1), y=np.arange(-4, 2.1, 0.1) )
input("Press Enter to continue...")
def main_quadratic2():
np.seterr(divide='ignore')
# the hessian matrix of the quadratic function
Q = np.matrix('5 2; 2 2')
# the vector of linear coefficient of the quadratic function
v = np.matrix('21; 13')
A = np.matrix('2 1; 2 -5;-1 1')
b = np.matrix('8; 10; 3')
mu = np.sqrt(2)
lower_t = 0.1249
upper_t = 2
#upper_t = 100
# Start at (0,0)
initial_x = np.matrix('0.0; 0.0')
# Find the (1e-8)-suboptimal solution
eps = 1e-8
maximum_iterations = 65536
ts = []
gd_iterations = []
newton_iterations = []
t = lower_t
while t <= upper_t:
func = lambda x, order: quadratic_log_barrier(Q, v, A, b, x, t, order)
ts.append(t)
# Run the algorithms
x, values, runtimes, gd_xs = alg.gradient_descent(
func, initial_x, eps, maximum_iterations,
alg.backtracking_line_search)
gd_iterations.append(len(values) - 1)
x, values, runtimes, newton_xs = alg.newton(
func, initial_x, eps, maximum_iterations,
alg.backtracking_line_search)
newton_iterations.append(len(values) - 1)
t *= mu
plt.plot(ts, gd_iterations, linewidth=2, color='r', label='GD', marker='o')
plt.plot(ts,
newton_iterations,
linewidth=2,
color='m',
label='Newton',
marker='o')
plt.xlabel('t')
plt.ylabel('iterations')
plt.legend()
plt.show()
# Choose the quadratic objective. This notation defines a "closure", returning
# an oracle function which takes x (and order) as its only parameter, and calls
# obj.quadratic with parameters H and b defined above, and the parameters of
# the closure (x and order)
func = lambda x, order: hw1_func.quadratic(H, b, x, order)
# Find the (1e-4)-suboptimal solution
eps = 1e-4
maximum_iterations = 65536
# Run the algorithms on the weird function
x = alg.bisection(hw1_func.weird_func, -100, 100, eps, maximum_iterations)
print('Optimum of the weird function found by bisection', x)
x, values, runtimes, gd_xs = alg.gradient_descent(hw1_func.weird_func, 0.0,
eps, maximum_iterations,
alg.exact_line_search)
print('Optimum of the weird function found by GD with exact line search', x)
x, values, runtimes, gd_xs = alg.newton(hw1_func.weird_func, 0.0, eps,
maximum_iterations,
alg.exact_line_search)
print('Optimum of the weird function found by Newton with exact line search',
x)
x, values, runtimes, gd_xs = alg.gradient_descent(hw1_func.weird_func, 0.0,
eps, maximum_iterations,
alg.backtracking_line_search)
print(
'Optimum of the weird function found by GD with backtracking line search',
x)
# Choose the quadratic objective. This notation defines a "closure", returning
# an oracle function which takes x (and order) as its only parameter, and calls
# obj.quadratic with parameters H and b defined above, and the parameters of
# the closure (x and order)
func = lambda x, order: hw_func.quadratic(H, b, x, order)
# Run algorithms on the weird function
eps = 1e-4
maximum_iterations = 65536
x = alg.bisection(hw_func.weird_func, -100, 100, eps, maximum_iterations)
print('Optimum of the weird function found by bisection', x)
x, values, runtimes, gd_xs = alg.gradient_descent(hw_func.weird_func, 0.0, eps,
maximum_iterations,
alg.backtracking_line_search)
print(
'Optimum of the weird function found by GD with backtracking line search',
x)
x, values, runtimes, gd_xs = alg.newton(hw_func.weird_func, 0.0, eps,
maximum_iterations,
alg.backtracking_line_search)
print(
'Optimum of the weird function found by Newton with backtracking line search',
x)
x, values, runtimes, gd_xs = alg.bfgs(hw_func.weird_func, 0.0, 1.0, eps,
maximum_iterations,
alg.backtracking_line_search)
# [1, 5, 205],
# [2, 4, 304],
# [3, 3, 403],
# [4, 2, 502],
# [5, 1, 601],
# [6, -10, 690],
# [7, -10, 790],
# [8, -1, 899],
# ]
training_set = [
[0, 1, 1, 1, 1],
[1, 1, 0, 1, 0],
[0, 1, 1, 0, 1],
[0, 0, 0, 0, 0],
[1, 1, 1, 1, 0],
[1, 0, 0, 0, 1],
[1, 0, 1, 1, 0],
[1, 1, 1, 0, 0],
[0, 0, 1, 0, 1],
[0, 1, 0, 1, 0],
[1, 0, 1, 1, 1],
[0, 1, 1, 0, 0],
[1, 0, 0, 1, 1],
]
hypo = LogisticHypothesis()
gradient_descent(hypothesis=hypo,
training_set=training_set,
convergent_criteria=0.001)
# [1, 5, 205],
# [2, 4, 304],
# [3, 3, 403],
# [4, 2, 502],
# [5, 1, 601],
# [6, -10, 690],
# [7, -10, 790],
# [8, -1, 899],
# ]
training_set = [
[0,1,1,1,1],
[1,1,0,1,0],
[0,1,1,0,1],
[0,0,0,0,0],
[1,1,1,1,0],
[1,0,0,0,1],
[1,0,1,1,0],
[1,1,1,0,0],
[0,0,1,0,1],
[0,1,0,1,0],
[1,0,1,1,1],
[0,1,1,0,0],
[1,0,0,1,1],
]
hypo = LogisticHypothesis();
gradient_descent(hypothesis=hypo,
training_set=training_set,
convergent_criteria=0.001)