def kernel_poly(matrix_1, matrix_2, parameters):
a = parameters[0]
b = parameters[1]
d = parameters[2]
matrix = inner_matrix(matrix_1, matrix_2)
K = (a * matrix + b)**d
return K
def kernel_quad(matrix_1, matrix_2, parameters):
c = parameters[0]
matrix = inner_matrix(matrix_1, matrix_2)
K = (matrix + c)**2
return K
def kernel_sigmoid(matrix_1, matrix_2, parameters):
alpha = parameters[0]
beta = parameters[1]
matrix = inner_matrix(matrix_1, matrix_2)
K = np.tanh(alpha * matrix + beta)
return K