# Copyright (c) 2013,2014, GPy authors (see AUTHORS.txt).
# Copyright (c) 2015, James Hensman
# Licensed under the BSD 3-clause license (see LICENSE.txt)
import sys
from .parameterization import Parameterized
import numpy as np
[docs]class Mapping(Parameterized):
"""
Base model for shared mapping behaviours
"""
def __init__(self, input_dim, output_dim, name='mapping'):
self.input_dim = input_dim
self.output_dim = output_dim
super(Mapping, self).__init__(name=name)
[docs] def f(self, X):
raise NotImplementedError
[docs] def gradients_X(self, dL_dF, X):
raise NotImplementedError
[docs] def update_gradients(self, dL_dF, X):
raise NotImplementedError
[docs] def to_dict(self):
raise NotImplementedError
def _save_to_input_dict(self):
input_dict = {}
input_dict["input_dim"] = self.input_dim
input_dict["output_dim"] = self.output_dim
input_dict["name"] = self.name
return input_dict
[docs] @staticmethod
def from_dict(input_dict):
"""
Instantiate an object of a derived class using the information
in input_dict (built by the to_dict method of the derived class).
More specifically, after reading the derived class from input_dict,
it calls the method _build_from_input_dict of the derived class.
Note: This method should not be overrided in the derived class. In case
it is needed, please override _build_from_input_dict instate.
:param dict input_dict: Dictionary with all the information needed to
instantiate the object.
"""
import copy
input_dict = copy.deepcopy(input_dict)
mapping_class = input_dict.pop('class')
input_dict["name"] = str(input_dict["name"])
import GPy
mapping_class = eval(mapping_class)
return mapping_class._build_from_input_dict(mapping_class, input_dict)
@staticmethod
def _build_from_input_dict(mapping_class, input_dict):
return mapping_class(**input_dict)
[docs]class Bijective_mapping(Mapping):
"""
This is a mapping that is bijective, i.e. you can go from X to f and
also back from f to X. The inverse mapping is called g().
"""
def __init__(self, input_dim, output_dim, name='bijective_mapping'):
super(Bijective_mapping, self).__init__(name=name)
[docs] def g(self, f):
"""Inverse mapping from output domain of the function to the inputs."""
raise NotImplementedError