def predict(self, X, return_projection=False):
"""Predicts the class of input test data.
Parameters
----------
x : numpy.array
The test data which is to be classified.
return_projection : bool, optional
returns the projection of test data on the margin
along with the class prediction.
Returns
-------
prediction : numpy.array
A numpy.array consisting of 1, 0, -1 denoting the class of
test data
projections : numpy.array, optional
The projection formed by the test data point on the
margin.
"""
if len(X.shape) == 1:
X = np.expand_dims(X, axis=0)
if len(self.classifiers) == 0:
raise ModelNotFittedError(
"Predict called before fitting the model.")
projections = np.zeros(X.shape[0])
predictions = np.zeros(X.shape[0], dtype=np.int64)
# If the input labels are not of as desired by svc i.e - [-1, 1]
if sorted(self.uniques) != [-1, 1]:
for j, x in enumerate(X):
for i, clas in enumerate(self.classifiers):
prediction, projection = self.classifiers[i].predict(
x, return_projection=True)
if int(prediction) == 1:
if projections[j] != 0:
projections[j] = 0
predictions[j] = 0
break
else:
predictions[j] = self.y[self.ind[i]]
projections[j] = float(projection)
else:
for j, x in enumerate(X):
projection = self.b
for i in range(self.n_support_vectors):
projection += self.support_lagrange_multipliers[i] * self.support_vectors_y[i] *\
self.kernel(self.support_vectors[i], x)
projections[j] = projection
predictions[j] = np.sign(projection)
if return_projection:
return predictions, projections
return predictions
def predict(self, X_test):
"""Fits and predicts using the dbscan unsupervised clustering algorithm.
Parameters
----------
X_test : numpy.ndarray
The testing features.
Returns
-------
y_target : numpy.ndarray
The class label corresponding to each testing feature.
"""
y_target = np.zeros(len(X_test), dtype=np.int64)
for i, x_test in enumerate(X_test):
# get its euclidean distance from each feature in training set.
dist = np.array([np.linalg.norm(x_test - x_train) for x_train in self.X])
# get the id of top n_neighbors closest neighbours
sorted_index = dist.argsort()[:self.n_neighbors]
# get the votes of these neighbors
k_nearest_neighbor_votes = self.y[sorted_index]
# get the mode of all the votes to get the final prediction
votes = Counter(k_nearest_neighbor_votes).most_common()
winner = votes[0][0]
y_target[i] = winner
return y_target
def vocab_one_hot(Y, vocab_size):
temp = np.zeros((Y.shape[0], Y.shape[1], vocab_size))
for i, _ in enumerate(Y):
temp[i] = np.eye(vocab_size)[Y[i]]
return temp
def setUp(self):
n_features = 5
n_dim = 3
self.n_comp = 3
self.X = np.zeros([n_features, n_dim])
for i in range(n_features):
self.X[i, 2] = i
self.X[i, 1] = 5 * i + 2
# X[i,1] = pow(i,2)
self.X[i, 0] = (5 - 2 * self.X[i, 0] - 3 * self.X[i, 1]) / 2
def to_onehot(y):
try:
import cupy
if isinstance(y, cupy.core.core.ndarray):
y = np.asnumpy(y)
except ImportError:
pass
unq, _ = numpy.unique(y, return_inverse=True)
a = np.zeros((len(y), len(unq)))
for i in range(len(y)):
a[i][int(y[i])] = 1.
return a
def setUp(self):
X11 = Distribution.radial_binary(pts=300,
mean=[0, 0],
st=1,
ed=2,
seed=20)
X22 = Distribution.radial_binary(pts=300,
mean=[0, 0],
st=4,
ed=5,
seed=10)
Y11 = np.ones(X11.shape[0])
Y22 = np.zeros(X11.shape[0])
X = np.vstack((X11, X22))
y = np.hstack((Y11, Y22))
y = to_onehot(y)
self.X_train, self.X_test, self.y_train, self.y_test = train_test_split(
X, y, test_size=50, random_state=42)
def fit(self, X, y, multiplier_threshold=1e-5):
"""Fits the svc model on training data.
Parameters
----------
X : numpy.array
The training features.
y : numpy.array
The training labels.
multiplier_threshold : float
The threshold for selecting lagrange multipliers.
Returns
-------
kernel_matrix : list of svm.SVC
A list of all the classifiers used for multi class classification
"""
X = np.array(X)
self.y = y
self.n = self.y.shape[0]
self.uniques, self.ind = np.unique(self.y, return_index=True)
self.n_classes = len(self.uniques)
# Do multi class classification
if sorted(self.uniques) != [-1, 1]:
y_list = [np.where(self.y == u, 1, -1) for u in self.uniques]
for y_i in y_list:
# Copy the current initializer
clf = SVC()
clf.kernel = self.kernel
clf.C = self.C
self.classifiers.append(clf.fit(X, y_i))
return
# create a gram matrix by taking the outer product of y
gram_matrix_y = np.outer(self.y, self.y)
K = self.__create_kernel_matrix(X)
gram_matrix_xy = gram_matrix_y * K
P = cvxopt.matrix(gram_matrix_xy)
q = cvxopt.matrix(-np.ones(self.n))
G1 = cvxopt.spmatrix(-1.0, range(self.n), range(self.n))
G2 = cvxopt.spmatrix(1, range(self.n), range(self.n))
G = cvxopt.matrix([[G1, G2]])
h1 = cvxopt.matrix(np.zeros(self.n))
h2 = cvxopt.matrix(np.ones(self.n) * self.C)
h = cvxopt.matrix([[h1, h2]])
A = cvxopt.matrix(self.y.astype(np.double)).trans()
b = cvxopt.matrix(0.0)
lagrange_multipliers = np.array(
list(cvxopt.solvers.qp(P, q, G, h, A, b)['x']))
lagrange_multiplier_indices = np.greater_equal(lagrange_multipliers,
multiplier_threshold)
lagrange_multiplier_indices = list(
map(list, lagrange_multiplier_indices.nonzero()))[0]
# self.support_vectors = np.take(X, lagrange_multiplier_indices, axis=1)
self.support_vectors = X[lagrange_multiplier_indices]
# print(X)
# print(lagrange_multiplier_indices)
# print(self.support_vectors)
# self.support_vectors_y = np.take(self.y, lagrange_multiplier_indices)
self.support_vectors_y = self.y[lagrange_multiplier_indices]
# self.support_lagrange_multipliers = np.take(lagrange_multipliers, lagrange_multiplier_indices)
self.support_lagrange_multipliers = lagrange_multipliers[
lagrange_multiplier_indices]
self.b = 0
self.n_support_vectors = self.support_vectors.shape[0]
for i in range(self.n_support_vectors):
kernel_trick = K[[lagrange_multiplier_indices[i]],
lagrange_multiplier_indices]
self.b += self.support_vectors_y[i] - np.sum(
self.support_lagrange_multipliers * self.support_vectors_y *
kernel_trick)
self.b /= self.n_support_vectors
self.classifiers = [self]
return self
