def fit(self, X, y, n_iterations=4000):
# Add dummy ones for bias weights
X = np.insert(X, 0, 1, axis=1)
n_samples, n_features = np.shape(X)
# Initialize parameters between [-1/sqrt(N), 1/sqrt(N)]
limit = 1 / math.sqrt(n_features)
self.param = np.random.uniform(-limit, limit, (n_features, ))
# Tune parameters for n iterations
for i in range(n_iterations):
# Make a new prediction
y_pred = self.sigmoid.function(X.dot(self.param))
if self.gradient_descent:
# Move against the gradient of the loss function with
# respect to the parameters to minimize the loss
self.param -= self.learning_rate * -(y - y_pred).dot(X)
else:
# Make a diagonal matrix of the sigmoid gradient column vector
diag_gradient = make_diagonal(
self.sigmoid.gradient(X.dot(self.param)))
# Batch opt:
self.param = np.linalg.pinv(X.T.dot(diag_gradient).dot(X)).dot(
X.T).dot(
diag_gradient.dot(X).dot(self.param) + y - y_pred)
def fit(self, X, y, n_iterations=4000):
self._initialize_parameters(X)
# Tune parameters for n iterations
for i in range(n_iterations):
# Make a new prediction
y_pred = self.sigmoid(X.dot(self.param))
if self.gradient_descent:
# Move against the gradient of the loss function with
# respect to the parameters to minimize the loss
self.param -= self.learning_rate * -(y - y_pred).dot(X)
else:
# Make a diagonal matrix of the sigmoid gradient column vector
diag_gradient = make_diagonal(self.sigmoid.gradient(X.dot(self.param)))
# Batch opt:
self.param = np.linalg.pinv(X.T.dot(diag_gradient).dot(X)).dot(X.T).dot(diag_gradient.dot(X).dot(self.param) + y - y_pred)