def test_grad_bs(self):
n = FeedForwardNetwork([4, 7, 2, 3])
x0 = np.random.uniform(size=4).astype(TYPE)
intermediate_results = {}
y = n.forward_prop(x0, intermediate_results)
t = np.zeros(3).astype(TYPE)
dy = mathutils.mean_squared_error_prime(y, t)
n.back_prop(dy, intermediate_results)
dbs = intermediate_results["dbs"]
delta = 1e-4
exp_dbs = []
for i in range(len(n.bs)):
b = n.bs[i]
exp_db = np.zeros(b.shape)
for index in np.ndindex(b.shape):
n1 = clone(n)
n2 = clone(n)
n1.bs[i][index] -= delta
n2.bs[i][index] += delta
exp_grad = (err(n2.forward_prop(x0, {})) - err(n1.forward_prop(x0, {}))) / (2 * delta)
exp_db[index] = exp_grad
exp_dbs.append(exp_db)
for dw, exp_db in zip(dbs, exp_dbs):
npt.assert_array_almost_equal(dw, exp_db, decimal=3)
def test_grad_ws(self):
n = FeedForwardNetwork([5, 4, 3, 2])
x0 = np.random.uniform(size=5).astype(TYPE)
intermediate_results = {}
y = n.forward_prop(x0, intermediate_results)
t = np.zeros(2).astype(TYPE)
dy = mathutils.mean_squared_error_prime(y, t)
n.back_prop(dy, intermediate_results)
dws = intermediate_results["dws"]
delta = 1e-4
exp_dws = []
for i in range(len(n.ws)):
w = n.ws[i]
exp_dw = np.zeros(w.shape)
for index in np.ndindex(w.shape):
n1 = clone(n)
n2 = clone(n)
n1.ws[i][index] -= delta
n2.ws[i][index] += delta
exp_grad = (err(n2.forward_prop(x0, {})) - err(n1.forward_prop(x0, {}))) / (2 * delta)
exp_dw[index] = exp_grad
exp_dws.append(exp_dw)
for dw, exp_dw in zip(dws, exp_dws):
npt.assert_array_almost_equal(dw, exp_dw, decimal=3)
def test_iris_data_set(self):
def create_data_entry(line):
split = line.strip().split(",")
data_input = np.array([float(str) / 7 for str in split[:-1]]).astype(TYPE)
classes = ["Iris-setosa", "Iris-versicolor", "Iris-virginica"]
data_target = np.array([float(split[-1] == class_) for class_ in classes]).astype(TYPE)
return data_input, data_target
iris_data_file = open("iris.data")
data_set = [create_data_entry(line) for line in iris_data_file.readlines() if line.strip()]
iris_data_file.close()
random.shuffle(data_set)
training_set = data_set[:-30]
test_set = data_set[-30:]
n = FeedForwardNetwork([4, 50, 3])
learning_rate = 0.5
for _ in range(10000):
training_input, training_target = training_set[random.randrange(0, len(training_set))]
intermediate_results = {}
y = n.forward_prop(training_input, intermediate_results)
dy = mathutils.mse_prime(y, training_target)
n.back_prop(dy, intermediate_results)
n.train(learning_rate, intermediate_results)
errors = [mathutils.mean_squared_error(n.forward_prop(test_input, {}), test_target) for test_input, test_target in test_set]
mean_squared_error = np.mean(np.square(errors))
npt.assert_array_less(mean_squared_error, 0.05)
def test_save_and_load(self):
n = FeedForwardNetwork([2, 3, 4])
n.ws = [np.array([[1, 1],
[0, -1],
[5, -9]]),
np.array([[2, 7, -4],
[0, -1, 1],
[6, 20, -10],
[3, 3, 3, 3]])]
n.bs = [np.array([[0], [0], [1]]),
np.array([[9], [1], [-1], [50]])]
temp_file = tempfile.mkstemp(suffix=".npz")[1]
n.save(temp_file)
n2 = FeedForwardNetwork([])
n2.load(temp_file)
for w, b, w2, b2 in zip(n.ws, n.bs, n2.ws, n2.bs):
npt.assert_equal(w, w2)
npt.assert_equal(b, b2)
os.remove(temp_file)
def test_grad_x(self):
n = FeedForwardNetwork([3, 4, 4, 2])
x0 = np.random.uniform(size=3).astype(TYPE)
intermediate_results = {}
y = n.forward_prop(x0, intermediate_results)
t = np.zeros(2).astype(TYPE)
dy = mathutils.mean_squared_error_prime(y, t)
dx = n.back_prop(dy, intermediate_results)
delta = 1e-4
exp_dx = np.zeros(x0.shape)
for index in np.ndindex(x0.shape):
x0_a = np.copy(x0)
x0_b = np.copy(x0)
x0_a[index] -= delta
x0_b[index] += delta
exp_grad = (err(n.forward_prop(x0_b, {})) - err(n.forward_prop(x0_a, {}))) / (2 * delta)
exp_dx[index] = exp_grad
npt.assert_array_almost_equal(dx, exp_dx, decimal=3)
def clone(n):
n2 = FeedForwardNetwork([9, 9])
n2.ws = [np.copy(w) for w in n.ws]
n2.bs = [np.copy(b) for b in n.bs]
return n2