def knn_classify(k, labeled_points, new_point):
"""each labeled point should be a pair (point, label)"""
# order the labeled points from nearest to farthest
by_distance = sorted(labeled_points,
key=lambda (point, _): distance(point, new_point))
# find the labels for the k closest
k_nearest_labels = [label for _, label in by_distance[:k]]
# and let them vote
return majority_vote(k_nearest_labels)
def knn_classify(k, labeled_points, new_point):
"""each labeled point should be a pair (point, label)"""
# order the labeled points from nearest to farthest
by_distance = sorted(labeled_points,
key=lambda (point, _): distance(point, new_point))
# find the labels for the k closest
k_nearest_labels = [label for _, label in by_distance[:k]]
# and let them vote
return majority_vote(k_nearest_labels)
def random_distances(dim, num_pairs):
return [
distance(random_point(dim), random_point(dim))
for _ in range(num_pairs)
]
def maximize_stochastic(target_fn, gradient_fn, x, y, theta_0, alpha_0=0.01):
return minimize_stochastic(negate(target_fn), negate_all(gradient_fn), x,
y, theta_0, alpha_0)
if __name__ == "__main__":
print "using the gradient"
v = [random.randint(-10, 10) for i in range(3)]
tolerance = 0.0000001
while True:
#print v, sum_of_squares(v)
gradient = sum_of_squares_gradient(v) # compute the gradient at v
next_v = step(v, gradient, -0.01) # take a negative gradient step
if distance(next_v, v) < tolerance: # stop if we're converging
break
v = next_v # continue if we're not
print "minimum v", v
print "minimum value", sum_of_squares(v)
print
print "using minimize_batch"
v = [random.randint(-10, 10) for i in range(3)]
v = minimize_batch(sum_of_squares, sum_of_squares_gradient, v)
print "minimum v", v
print "minimum value", sum_of_squares(v)
def random_distances(dim, num_pairs):
return [distance(random_point(dim), random_point(dim))
for _ in range(num_pairs)]
return minimize_stochastic(negate(target_fn),
negate_all(gradient_fn),
x, y, theta_0, alpha_0)
if __name__ == "__main__":
print "using the gradient"
v = [random.randint(-10,10) for i in range(3)]
tolerance = 0.0000001
while True:
#print v, sum_of_squares(v)
gradient = sum_of_squares_gradient(v) # compute the gradient at v
next_v = step(v, gradient, -0.01) # take a negative gradient step
if distance(next_v, v) < tolerance: # stop if we're converging
break
v = next_v # continue if we're not
print "minimum v", v
print "minimum value", sum_of_squares(v)
print
print "using minimize_batch"
v = [random.randint(-10,10) for i in range(3)]
v = minimize_batch(sum_of_squares, sum_of_squares_gradient, v)
print "minimum v", v
print "minimum value", sum_of_squares(v)