def __init__(self, train_X=None, valid_X=None, test_X=None, args=None, logger=None):
     # Output logger
     self.logger = logger
     self.outdir = args.get("output_path", defaults["output_path"])
     if self.outdir[-1] != '/':
         self.outdir = self.outdir+'/'
     # Input data - make sure it is a list of shared datasets
     self.train_X = raise_data_to_list(train_X)
     self.valid_X = raise_data_to_list(valid_X)
     self.test_X  = raise_data_to_list(test_X)
     
     # variables from the dataset that are used for initialization and image reconstruction
     if train_X is None:
         self.N_input = args.get("input_size")
         if args.get("input_size") is None:
             raise AssertionError("Please either specify input_size in the arguments or provide an example train_X for input dimensionality.")
     else:
         self.N_input = train_X[0].eval().shape[1]
     self.root_N_input = numpy.sqrt(self.N_input)
     
     self.is_image = args.get('is_image', defaults['is_image'])
     if self.is_image:
         self.image_width  = args.get('width', self.root_N_input)
         self.image_height = args.get('height', self.root_N_input)
     
     #######################################
     # Network and training specifications #
     #######################################
     self.layers          = args.get('layers', defaults['layers']) # number hidden layers
     self.walkbacks       = args.get('walkbacks', defaults['walkbacks']) # number of walkbacks
     self.learning_rate   = theano.shared(cast32(args.get('learning_rate', defaults['learning_rate'])))  # learning rate
     self.init_learn_rate = cast32(args.get('learning_rate', defaults['learning_rate']))
     self.momentum        = theano.shared(cast32(args.get('momentum', defaults['momentum']))) # momentum term
     self.annealing       = cast32(args.get('annealing', defaults['annealing'])) # exponential annealing coefficient
     self.noise_annealing = cast32(args.get('noise_annealing', defaults['noise_annealing'])) # exponential noise annealing coefficient
     self.batch_size      = args.get('batch_size', defaults['batch_size'])
     self.n_epoch         = args.get('n_epoch', defaults['n_epoch'])
     self.early_stop_threshold = args.get('early_stop_threshold', defaults['early_stop_threshold'])
     self.early_stop_length = args.get('early_stop_length', defaults['early_stop_length'])
     self.save_frequency  = args.get('save_frequency', defaults['save_frequency'])
     
     self.noiseless_h1           = args.get('noiseless_h1', defaults["noiseless_h1"])
     self.hidden_add_noise_sigma = theano.shared(cast32(args.get('hidden_add_noise_sigma', defaults["hidden_add_noise_sigma"])))
     self.input_salt_and_pepper  = theano.shared(cast32(args.get('input_salt_and_pepper', defaults["input_salt_and_pepper"])))
     self.input_sampling         = args.get('input_sampling', defaults["input_sampling"])
     self.vis_init               = args.get('vis_init', defaults['vis_init'])
     
     self.layer_sizes = [self.N_input] + [args.get('hidden_size', defaults['hidden_size'])] * self.layers # layer sizes, from h0 to hK (h0 is the visible layer)
     
     self.f_recon = None
     self.f_noise = None
     
     # Activation functions!            
     if args.get('hidden_activation') is not None:
         log.maybeLog(self.logger, 'Using specified activation for hiddens')
         self.hidden_activation = args.get('hidden_activation')
     elif args.get('hidden_act') is not None:
         self.hidden_activation = get_activation_function(args.get('hidden_act'))
         log.maybeLog(self.logger, 'Using {0!s} activation for hiddens'.format(args.get('hidden_act')))
     else:
         log.maybeLog(self.logger, "Using default activation for hiddens")
         self.hidden_activation = defaults['hidden_activation']
         
     # Visible layer activation
     if args.get('visible_activation') is not None:
         log.maybeLog(self.logger, 'Using specified activation for visible layer')
         self.visible_activation = args.get('visible_activation')
     elif args.get('visible_act') is not None:
         self.visible_activation = get_activation_function(args.get('visible_act'))
         log.maybeLog(self.logger, 'Using {0!s} activation for visible layer'.format(args.get('visible_act')))
     else:
         log.maybeLog(self.logger, 'Using default activation for visible layer')
         self.visible_activation = defaults['visible_activation']
         
     # Cost function!
     if args.get('cost_function') is not None:
         log.maybeLog(self.logger, '\nUsing specified cost function for training\n')
         self.cost_function = args.get('cost_function')
     elif args.get('cost_funct') is not None:
         self.cost_function = get_cost_function(args.get('cost_funct'))
         log.maybeLog(self.logger, 'Using {0!s} for cost function'.format(args.get('cost_funct')))
     else:
         log.maybeLog(self.logger, '\nUsing default cost function for training\n')
         self.cost_function = defaults['cost_function']
     
     ############################
     # Theano variables and RNG #
     ############################
     self.X   = T.fmatrix('X') # for use in sampling
     self.MRG = RNG_MRG.MRG_RandomStreams(1)
     rng.seed(1)
     
     ###############
     # Parameters! #
     ###############
     # initialize a list of weights and biases based on layer_sizes for the GSN
     if args.get('weights_list') is None:
         self.weights_list = [get_shared_weights(self.layer_sizes[layer], self.layer_sizes[layer+1], name="W_{0!s}_{1!s}".format(layer,layer+1)) for layer in range(self.layers)] # initialize each layer to uniform sample from sqrt(6. / (n_in + n_out))
     else:
         self.weights_list = args.get('weights_list')
     if args.get('bias_list') is None:
         self.bias_list    = [get_shared_bias(self.layer_sizes[layer], name='b_'+str(layer)) for layer in range(self.layers + 1)] # initialize each layer to 0's.
     else:
         self.bias_list    = args.get('bias_list')
     self.params = self.weights_list + self.bias_list
     
     #################
     # Build the GSN #
     #################
     log.maybeLog(self.logger, "\nBuilding GSN graphs for training and testing")
     # GSN for training - with noise
     add_noise = True
     p_X_chain, _ = build_gsn(self.X,
                              self.weights_list,
                              self.bias_list,
                              add_noise,
                              self.noiseless_h1,
                              self.hidden_add_noise_sigma,
                              self.input_salt_and_pepper,
                              self.input_sampling,
                              self.MRG,
                              self.visible_activation,
                              self.hidden_activation,
                              self.walkbacks,
                              self.logger)
     
     # GSN for reconstruction checks along the way - no noise
     add_noise = False
     p_X_chain_recon, _ = build_gsn(self.X,
                                    self.weights_list,
                                    self.bias_list,
                                    add_noise,
                                    self.noiseless_h1,
                                    self.hidden_add_noise_sigma,
                                    self.input_salt_and_pepper,
                                    self.input_sampling,
                                    self.MRG,
                                    self.visible_activation,
                                    self.hidden_activation,
                                    self.walkbacks,
                                    self.logger)
     
     #######################
     # Costs and gradients #
     #######################
     log.maybeLog(self.logger, 'Cost w.r.t p(X|...) at every step in the graph for the GSN')
     gsn_costs     = [self.cost_function(rX, self.X) for rX in p_X_chain]
     show_gsn_cost = gsn_costs[-1] # for logging to show progress
     gsn_cost      = numpy.sum(gsn_costs)
     
     gsn_costs_recon     = [self.cost_function(rX, self.X) for rX in p_X_chain_recon]
     show_gsn_cost_recon = gsn_costs_recon[-1]
     
     log.maybeLog(self.logger, ["gsn params:", self.params])
     
     # Stochastic gradient descent!
     gradient        =   T.grad(gsn_cost, self.params)              
     gradient_buffer =   [theano.shared(numpy.zeros(param.get_value().shape, dtype='float32')) for param in self.params] 
     m_gradient      =   [self.momentum * gb + (cast32(1) - self.momentum) * g for (gb, g) in zip(gradient_buffer, gradient)]
     param_updates   =   [(param, param - self.learning_rate * mg) for (param, mg) in zip(self.params, m_gradient)]
     gradient_buffer_updates = zip(gradient_buffer, m_gradient)
     updates         =   OrderedDict(param_updates + gradient_buffer_updates)
     
     ############
     # Sampling #
     ############
     # the input to the sampling function
     X_sample = T.fmatrix("X_sampling")
     self.network_state_input = [X_sample] + [T.fmatrix("H_sampling_"+str(i+1)) for i in range(self.layers)]
    
     # "Output" state of the network (noisy)
     # initialized with input, then we apply updates
     self.network_state_output = [X_sample] + self.network_state_input[1:]
     visible_pX_chain = []
 
     # ONE update
     log.maybeLog(self.logger, "Performing one walkback in network state sampling.")
     update_layers(self.network_state_output,
                   self.weights_list,
                   self.bias_list,
                   visible_pX_chain, 
                   True,
                   self.noiseless_h1,
                   self.hidden_add_noise_sigma,
                   self.input_salt_and_pepper,
                   self.input_sampling,
                   self.MRG,
                   self.visible_activation,
                   self.hidden_activation,
                   self.logger)
     
     #################################
     #     Create the functions      #
     #################################
     log.maybeLog(self.logger, "Compiling functions...")
     t = time.time()
     
     self.f_learn = theano.function(inputs  = [self.X],
                               updates = updates,
                               outputs = show_gsn_cost,
                               name='gsn_f_learn')
 
     self.f_cost  = theano.function(inputs  = [self.X],
                               outputs = show_gsn_cost,
                               name='gsn_f_cost')
     
     # used for checkpoints and testing - no noise in network
     self.f_recon = theano.function(inputs  = [self.X],
                                    outputs = [show_gsn_cost_recon, p_X_chain_recon[-1]],
                                    name='gsn_f_recon')
     
     self.f_noise = theano.function(inputs = [self.X],
                                    outputs = salt_and_pepper(self.X, self.input_salt_and_pepper),
                                    name='gsn_f_noise')
 
     if self.layers == 1: 
         self.f_sample = theano.function(inputs = [X_sample], 
                                         outputs = visible_pX_chain[-1], 
                                         name='gsn_f_sample_single_layer')
     else:
         # WHY IS THERE A WARNING????
         # because the first odd layers are not used -> directly computed FROM THE EVEN layers
         # unused input = warn
         self.f_sample = theano.function(inputs = self.network_state_input,
                                         outputs = self.network_state_output + visible_pX_chain,
                                         on_unused_input='warn',
                                         name='gsn_f_sample')
     
     log.maybeLog(self.logger, "Compiling done. Took "+make_time_units_string(time.time() - t)+".\n")
Beispiel #2
0
    def __init__(self,
                 train_X=None,
                 valid_X=None,
                 test_X=None,
                 args=None,
                 logger=None):
        # Output logger
        self.logger = logger
        self.outdir = args.get("output_path", defaults["output_path"])
        if self.outdir[-1] != '/':
            self.outdir = self.outdir + '/'
        # Input data - make sure it is a list of shared datasets
        self.train_X = raise_data_to_list(train_X)
        self.valid_X = raise_data_to_list(valid_X)
        self.test_X = raise_data_to_list(test_X)

        # variables from the dataset that are used for initialization and image reconstruction
        if train_X is None:
            self.N_input = args.get("input_size")
            if args.get("input_size") is None:
                raise AssertionError(
                    "Please either specify input_size in the arguments or provide an example train_X for input dimensionality."
                )
        else:
            self.N_input = train_X[0].eval().shape[1]
        self.root_N_input = numpy.sqrt(self.N_input)

        self.is_image = args.get('is_image', defaults['is_image'])
        if self.is_image:
            self.image_width = args.get('width', self.root_N_input)
            self.image_height = args.get('height', self.root_N_input)

        #######################################
        # Network and training specifications #
        #######################################
        self.layers = args.get('layers',
                               defaults['layers'])  # number hidden layers
        self.walkbacks = args.get('walkbacks',
                                  defaults['walkbacks'])  # number of walkbacks
        self.learning_rate = theano.shared(
            cast32(args.get('learning_rate',
                            defaults['learning_rate'])))  # learning rate
        self.init_learn_rate = cast32(
            args.get('learning_rate', defaults['learning_rate']))
        self.momentum = theano.shared(
            cast32(args.get('momentum',
                            defaults['momentum'])))  # momentum term
        self.annealing = cast32(args.get(
            'annealing',
            defaults['annealing']))  # exponential annealing coefficient
        self.noise_annealing = cast32(
            args.get('noise_annealing', defaults['noise_annealing'])
        )  # exponential noise annealing coefficient
        self.batch_size = args.get('batch_size', defaults['batch_size'])
        self.n_epoch = args.get('n_epoch', defaults['n_epoch'])
        self.early_stop_threshold = args.get('early_stop_threshold',
                                             defaults['early_stop_threshold'])
        self.early_stop_length = args.get('early_stop_length',
                                          defaults['early_stop_length'])
        self.save_frequency = args.get('save_frequency',
                                       defaults['save_frequency'])

        self.noiseless_h1 = args.get('noiseless_h1', defaults["noiseless_h1"])
        self.hidden_add_noise_sigma = theano.shared(
            cast32(
                args.get('hidden_add_noise_sigma',
                         defaults["hidden_add_noise_sigma"])))
        self.input_salt_and_pepper = theano.shared(
            cast32(
                args.get('input_salt_and_pepper',
                         defaults["input_salt_and_pepper"])))
        self.input_sampling = args.get('input_sampling',
                                       defaults["input_sampling"])
        self.vis_init = args.get('vis_init', defaults['vis_init'])

        self.layer_sizes = [self.N_input] + [
            args.get('hidden_size', defaults['hidden_size'])
        ] * self.layers  # layer sizes, from h0 to hK (h0 is the visible layer)

        self.f_recon = None
        self.f_noise = None

        # Activation functions!
        if args.get('hidden_activation') is not None:
            log.maybeLog(self.logger, 'Using specified activation for hiddens')
            self.hidden_activation = args.get('hidden_activation')
        elif args.get('hidden_act') is not None:
            self.hidden_activation = get_activation_function(
                args.get('hidden_act'))
            log.maybeLog(
                self.logger, 'Using {0!s} activation for hiddens'.format(
                    args.get('hidden_act')))
        else:
            log.maybeLog(self.logger, "Using default activation for hiddens")
            self.hidden_activation = defaults['hidden_activation']

        # Visible layer activation
        if args.get('visible_activation') is not None:
            log.maybeLog(self.logger,
                         'Using specified activation for visible layer')
            self.visible_activation = args.get('visible_activation')
        elif args.get('visible_act') is not None:
            self.visible_activation = get_activation_function(
                args.get('visible_act'))
            log.maybeLog(
                self.logger, 'Using {0!s} activation for visible layer'.format(
                    args.get('visible_act')))
        else:
            log.maybeLog(self.logger,
                         'Using default activation for visible layer')
            self.visible_activation = defaults['visible_activation']

        # Cost function!
        if args.get('cost_function') is not None:
            log.maybeLog(self.logger,
                         '\nUsing specified cost function for training\n')
            self.cost_function = args.get('cost_function')
        elif args.get('cost_funct') is not None:
            self.cost_function = get_cost_function(args.get('cost_funct'))
            log.maybeLog(
                self.logger,
                'Using {0!s} for cost function'.format(args.get('cost_funct')))
        else:
            log.maybeLog(self.logger,
                         '\nUsing default cost function for training\n')
            self.cost_function = defaults['cost_function']

        ############################
        # Theano variables and RNG #
        ############################
        self.X = T.fmatrix('X')  # for use in sampling
        self.MRG = RNG_MRG.MRG_RandomStreams(1)
        rng.seed(1)

        ###############
        # Parameters! #
        ###############
        # initialize a list of weights and biases based on layer_sizes for the GSN
        if args.get('weights_list') is None:
            self.weights_list = [
                get_shared_weights(self.layer_sizes[layer],
                                   self.layer_sizes[layer + 1],
                                   name="W_{0!s}_{1!s}".format(
                                       layer, layer + 1))
                for layer in range(self.layers)
            ]  # initialize each layer to uniform sample from sqrt(6. / (n_in + n_out))
        else:
            self.weights_list = args.get('weights_list')
        if args.get('bias_list') is None:
            self.bias_list = [
                get_shared_bias(self.layer_sizes[layer],
                                name='b_' + str(layer))
                for layer in range(self.layers + 1)
            ]  # initialize each layer to 0's.
        else:
            self.bias_list = args.get('bias_list')
        self.params = self.weights_list + self.bias_list

        #################
        # Build the GSN #
        #################
        log.maybeLog(self.logger,
                     "\nBuilding GSN graphs for training and testing")
        # GSN for training - with noise
        add_noise = True
        p_X_chain, _ = build_gsn(
            self.X, self.weights_list, self.bias_list, add_noise,
            self.noiseless_h1, self.hidden_add_noise_sigma,
            self.input_salt_and_pepper, self.input_sampling, self.MRG,
            self.visible_activation, self.hidden_activation, self.walkbacks,
            self.logger)

        # GSN for reconstruction checks along the way - no noise
        add_noise = False
        p_X_chain_recon, _ = build_gsn(
            self.X, self.weights_list, self.bias_list, add_noise,
            self.noiseless_h1, self.hidden_add_noise_sigma,
            self.input_salt_and_pepper, self.input_sampling, self.MRG,
            self.visible_activation, self.hidden_activation, self.walkbacks,
            self.logger)

        #######################
        # Costs and gradients #
        #######################
        log.maybeLog(
            self.logger,
            'Cost w.r.t p(X|...) at every step in the graph for the GSN')
        gsn_costs = [self.cost_function(rX, self.X) for rX in p_X_chain]
        show_gsn_cost = gsn_costs[-1]  # for logging to show progress
        gsn_cost = numpy.sum(gsn_costs)

        gsn_costs_recon = [
            self.cost_function(rX, self.X) for rX in p_X_chain_recon
        ]
        show_gsn_cost_recon = gsn_costs_recon[-1]

        log.maybeLog(self.logger, ["gsn params:", self.params])

        # Stochastic gradient descent!
        gradient = T.grad(gsn_cost, self.params)
        gradient_buffer = [
            theano.shared(numpy.zeros(param.get_value().shape,
                                      dtype='float32'))
            for param in self.params
        ]
        m_gradient = [
            self.momentum * gb + (cast32(1) - self.momentum) * g
            for (gb, g) in zip(gradient_buffer, gradient)
        ]
        param_updates = [(param, param - self.learning_rate * mg)
                         for (param, mg) in zip(self.params, m_gradient)]
        gradient_buffer_updates = zip(gradient_buffer, m_gradient)
        updates = OrderedDict(param_updates + gradient_buffer_updates)

        ############
        # Sampling #
        ############
        # the input to the sampling function
        X_sample = T.fmatrix("X_sampling")
        self.network_state_input = [X_sample] + [
            T.fmatrix("H_sampling_" + str(i + 1)) for i in range(self.layers)
        ]

        # "Output" state of the network (noisy)
        # initialized with input, then we apply updates
        self.network_state_output = [X_sample] + self.network_state_input[1:]
        visible_pX_chain = []

        # ONE update
        log.maybeLog(self.logger,
                     "Performing one walkback in network state sampling.")
        update_layers(self.network_state_output, self.weights_list,
                      self.bias_list, visible_pX_chain, True,
                      self.noiseless_h1, self.hidden_add_noise_sigma,
                      self.input_salt_and_pepper, self.input_sampling,
                      self.MRG, self.visible_activation,
                      self.hidden_activation, self.logger)

        #################################
        #     Create the functions      #
        #################################
        log.maybeLog(self.logger, "Compiling functions...")
        t = time.time()

        self.f_learn = theano.function(inputs=[self.X],
                                       updates=updates,
                                       outputs=show_gsn_cost,
                                       name='gsn_f_learn')

        self.f_cost = theano.function(inputs=[self.X],
                                      outputs=show_gsn_cost,
                                      name='gsn_f_cost')

        # used for checkpoints and testing - no noise in network
        self.f_recon = theano.function(
            inputs=[self.X],
            outputs=[show_gsn_cost_recon, p_X_chain_recon[-1]],
            name='gsn_f_recon')

        self.f_noise = theano.function(inputs=[self.X],
                                       outputs=salt_and_pepper(
                                           self.X, self.input_salt_and_pepper),
                                       name='gsn_f_noise')

        if self.layers == 1:
            self.f_sample = theano.function(inputs=[X_sample],
                                            outputs=visible_pX_chain[-1],
                                            name='gsn_f_sample_single_layer')
        else:
            # WHY IS THERE A WARNING????
            # because the first odd layers are not used -> directly computed FROM THE EVEN layers
            # unused input = warn
            self.f_sample = theano.function(inputs=self.network_state_input,
                                            outputs=self.network_state_output +
                                            visible_pX_chain,
                                            on_unused_input='warn',
                                            name='gsn_f_sample')

        log.maybeLog(
            self.logger, "Compiling done. Took " +
            make_time_units_string(time.time() - t) + ".\n")
Beispiel #3
0
    def __init__(self, train_X=None, train_Y=None, valid_X=None, valid_Y=None, test_X=None, test_Y=None, args=None, logger=None):
        # Output logger
        self.logger = logger
        self.outdir = args.get("output_path", defaults["output_path"])
        if self.outdir[-1] != '/':
            self.outdir = self.outdir+'/'
            
        data.mkdir_p(self.outdir)
        
        # Configuration
        config_filename = self.outdir+'config'
        logger.log('Saving config')
        with open(config_filename, 'w') as f:
            f.write(str(args))
 
        # Input data - make sure it is a list of shared datasets if it isn't. THIS WILL KEEP 'NONE' AS 'NONE' no need to worry :)
        self.train_X = raise_to_list(train_X)
        self.train_Y = raise_to_list(train_Y)
        self.valid_X = raise_to_list(valid_X)
        self.valid_Y = raise_to_list(valid_Y)
        self.test_X  = raise_to_list(test_X)
        self.test_Y  = raise_to_list(test_Y)
                
        # variables from the dataset that are used for initialization and image reconstruction
        if self.train_X is None:
            self.N_input = args.get("input_size")
            if args.get("input_size") is None:
                raise AssertionError("Please either specify input_size in the arguments or provide an example train_X for input dimensionality.")
        else:
            self.N_input = self.train_X[0].get_value(borrow=True).shape[1]
        
        self.is_image = args.get('is_image', defaults['is_image'])
        if self.is_image:
            (_h, _w) = closest_to_square_factors(self.N_input)
            self.image_width  = args.get('width', _w)
            self.image_height = args.get('height', _h)
            
        #######################################
        # Network and training specifications #
        #######################################
        self.layers          = args.get('layers', defaults['layers']) # number hidden layers
        self.walkbacks       = args.get('walkbacks', defaults['walkbacks']) # number of walkbacks
        self.learning_rate   = theano.shared(cast32(args.get('learning_rate', defaults['learning_rate'])))  # learning rate
        self.init_learn_rate = cast32(args.get('learning_rate', defaults['learning_rate']))
        self.momentum        = theano.shared(cast32(args.get('momentum', defaults['momentum']))) # momentum term
        self.annealing       = cast32(args.get('annealing', defaults['annealing'])) # exponential annealing coefficient
        self.noise_annealing = cast32(args.get('noise_annealing', defaults['noise_annealing'])) # exponential noise annealing coefficient
        self.batch_size      = args.get('batch_size', defaults['batch_size'])
        self.gsn_batch_size = args.get('gsn_batch_size', defaults['gsn_batch_size'])
        self.n_epoch         = args.get('n_epoch', defaults['n_epoch'])
        self.early_stop_threshold = args.get('early_stop_threshold', defaults['early_stop_threshold'])
        self.early_stop_length = args.get('early_stop_length', defaults['early_stop_length'])
        self.save_frequency  = args.get('save_frequency', defaults['save_frequency'])
        
        self.noiseless_h1           = args.get('noiseless_h1', defaults["noiseless_h1"])
        self.hidden_add_noise_sigma = theano.shared(cast32(args.get('hidden_add_noise_sigma', defaults["hidden_add_noise_sigma"])))
        self.input_salt_and_pepper  = theano.shared(cast32(args.get('input_salt_and_pepper', defaults["input_salt_and_pepper"])))
        self.input_sampling         = args.get('input_sampling', defaults["input_sampling"])
        self.vis_init               = args.get('vis_init', defaults['vis_init'])
        self.initialize_gsn         = args.get('initialize_gsn', defaults['initialize_gsn'])
        self.hessian_free           = args.get('hessian_free', defaults['hessian_free'])
        
        self.hidden_size = args.get('hidden_size', defaults['hidden_size'])
        self.layer_sizes = [self.N_input] + [self.hidden_size] * self.layers # layer sizes, from h0 to hK (h0 is the visible layer)
        self.recurrent_hidden_size = args.get('recurrent_hidden_size', defaults['recurrent_hidden_size'])
        
        self.f_recon = None
        self.f_noise = None
        
        # Activation functions!
        # For the GSN:
        if args.get('hidden_activation') is not None:
            log.maybeLog(self.logger, 'Using specified activation for GSN hiddens')
            self.hidden_activation = args.get('hidden_activation')
        elif args.get('hidden_act') is not None:
            self.hidden_activation = get_activation_function(args.get('hidden_act'))
            log.maybeLog(self.logger, 'Using {0!s} activation for GSN hiddens'.format(args.get('hidden_act')))
        else:
            log.maybeLog(self.logger, "Using default activation for GSN hiddens")
            self.hidden_activation = defaults['hidden_activation']
            
        # For the RNN:
        if args.get('recurrent_hidden_activation') is not None:
            log.maybeLog(self.logger, 'Using specified activation for RNN hiddens')
            self.recurrent_hidden_activation = args.get('recurrent_hidden_activation')
        elif args.get('recurrent_hidden_act') is not None:
            self.recurrent_hidden_activation = get_activation_function(args.get('recurrent_hidden_act'))
            log.maybeLog(self.logger, 'Using {0!s} activation for RNN hiddens'.format(args.get('recurrent_hidden_act')))
        else:
            log.maybeLog(self.logger, "Using default activation for RNN hiddens")
            self.recurrent_hidden_activation = defaults['recurrent_hidden_activation']
            
        # Visible layer activation
        if args.get('visible_activation') is not None:
            log.maybeLog(self.logger, 'Using specified activation for visible layer')
            self.visible_activation = args.get('visible_activation')
        elif args.get('visible_act') is not None:
            self.visible_activation = get_activation_function(args.get('visible_act'))
            log.maybeLog(self.logger, 'Using {0!s} activation for visible layer'.format(args.get('visible_act')))
        else:
            log.maybeLog(self.logger, 'Using default activation for visible layer')
            self.visible_activation = defaults['visible_activation']
            
        # Cost function!
        if args.get('cost_function') is not None:
            log.maybeLog(self.logger, '\nUsing specified cost function for GSN training\n')
            self.cost_function = args.get('cost_function')
        elif args.get('cost_funct') is not None:
            self.cost_function = get_cost_function(args.get('cost_funct'))
            log.maybeLog(self.logger, 'Using {0!s} for cost function'.format(args.get('cost_funct')))
        else:
            log.maybeLog(self.logger, '\nUsing default cost function for GSN training\n')
            self.cost_function = defaults['cost_function']
        
        ############################
        # Theano variables and RNG #
        ############################
        self.X = T.fmatrix('X') #single (batch) for training gsn
        self.Xs = T.fmatrix('Xs') #sequence for training rnn-gsn
        self.MRG = RNG_MRG.MRG_RandomStreams(1)
        
        ###############
        # Parameters! #
        ###############
        #gsn
        self.weights_list = [get_shared_weights(self.layer_sizes[i], self.layer_sizes[i+1], name="W_{0!s}_{1!s}".format(i,i+1)) for i in range(self.layers)] # initialize each layer to uniform sample from sqrt(6. / (n_in + n_out))
        self.bias_list    = [get_shared_bias(self.layer_sizes[i], name='b_'+str(i)) for i in range(self.layers + 1)] # initialize each layer to 0's.
        
        #recurrent
        self.recurrent_to_gsn_weights_list = [get_shared_weights(self.recurrent_hidden_size, self.layer_sizes[layer], name="W_u_h{0!s}".format(layer)) for layer in range(self.layers+1) if layer%2 != 0]
        self.W_u_u = get_shared_weights(self.recurrent_hidden_size, self.recurrent_hidden_size, name="W_u_u")
        self.W_x_u = get_shared_weights(self.N_input, self.recurrent_hidden_size, name="W_x_u")
        self.recurrent_bias = get_shared_bias(self.recurrent_hidden_size, name='b_u')
        
        #lists for use with gradients
        self.gsn_params = self.weights_list + self.bias_list
        self.u_params   = [self.W_u_u, self.W_x_u, self.recurrent_bias]
        self.params     = self.gsn_params + self.recurrent_to_gsn_weights_list + self.u_params
        
        ###########################################################
        #           load initial parameters of gsn                #
        ###########################################################
        self.train_gsn_first = False
        if self.initialize_gsn:
            params_to_load = 'gsn_params_epoch_30.pkl'
            if not os.path.isfile(params_to_load):
                self.train_gsn_first = True 
            else:
                log.maybeLog(self.logger, "\nLoading existing GSN parameters\n")
                loaded_params = cPickle.load(open(params_to_load,'r'))
                [p.set_value(lp.get_value(borrow=False)) for lp, p in zip(loaded_params[:len(self.weights_list)], self.weights_list)]
                [p.set_value(lp.get_value(borrow=False)) for lp, p in zip(loaded_params[len(self.weights_list):], self.bias_list)]
                
        if self.initialize_gsn:
            self.gsn_args = {'weights_list':       self.weights_list,
                             'bias_list':          self.bias_list,
                             'hidden_activation':  self.hidden_activation,
                             'visible_activation': self.visible_activation,
                             'cost_function':      self.cost_function,
                             'layers':             self.layers,
                             'walkbacks':          self.walkbacks,
                             'hidden_size':        self.hidden_size,
                             'learning_rate':      args.get('learning_rate', defaults['learning_rate']),
                             'momentum':           args.get('momentum', defaults['momentum']),
                             'annealing':          self.annealing,
                             'noise_annealing':    self.noise_annealing,
                             'batch_size':         self.gsn_batch_size,
                             'n_epoch':            self.n_epoch,
                             'early_stop_threshold':   self.early_stop_threshold,
                             'early_stop_length':      self.early_stop_length,
                             'save_frequency':         self.save_frequency,
                             'noiseless_h1':           self.noiseless_h1,
                             'hidden_add_noise_sigma': args.get('hidden_add_noise_sigma', defaults['hidden_add_noise_sigma']),
                             'input_salt_and_pepper':  args.get('input_salt_and_pepper', defaults['input_salt_and_pepper']),
                             'input_sampling':      self.input_sampling,
                             'vis_init':            self.vis_init,
                             'output_path':         self.outdir+'gsn/',
                             'is_image':            self.is_image,
                             'input_size':          self.N_input
                             }
            
        ############
        # Sampling #
        ############
        # the input to the sampling function
        X_sample = T.fmatrix("X_sampling")
        self.network_state_input = [X_sample] + [T.fmatrix("H_sampling_"+str(i+1)) for i in range(self.layers)]
       
        # "Output" state of the network (noisy)
        # initialized with input, then we apply updates
        self.network_state_output = [X_sample] + self.network_state_input[1:]
        visible_pX_chain = []
    
        # ONE update
        _add_noise = True
        log.maybeLog(self.logger, "Performing one walkback in network state sampling.")
        GSN.update_layers(self.network_state_output,
                          self.weights_list,
                          self.bias_list,
                          visible_pX_chain, 
                          _add_noise,
                          self.noiseless_h1,
                          self.hidden_add_noise_sigma,
                          self.input_salt_and_pepper,
                          self.input_sampling,
                          self.MRG,
                          self.visible_activation,
                          self.hidden_activation,
                          self.logger)
    
               
        #############################################
        #      Build the graphs for the RNN-GSN     #
        #############################################
        # If `x_t` is given, deterministic recurrence to compute the u_t. Otherwise, first generate
        def recurrent_step(x_t, u_tm1, add_noise):
            # Make current guess for hiddens based on U
            for i in range(self.layers):
                if i%2 == 0:
                    log.maybeLog(self.logger, "Using {0!s} and {1!s}".format(self.recurrent_to_gsn_weights_list[(i+1)/2],self.bias_list[i+1]))
            h_t = T.concatenate([self.hidden_activation(self.bias_list[i+1] + T.dot(u_tm1, self.recurrent_to_gsn_weights_list[(i+1)/2])) for i in range(self.layers) if i%2 == 0],axis=0)
            
            generate = x_t is None
            if generate:
                pass
            
            # Make a GSN to update U
    #         chain, hs = gsn.build_gsn(x_t, weights_list, bias_list, add_noise, state.noiseless_h1, state.hidden_add_noise_sigma, state.input_salt_and_pepper, state.input_sampling, MRG, visible_activation, hidden_activation, walkbacks, logger)
    #         htop_t = hs[-1]
    #         denoised_x_t = chain[-1]
            # Update U
    #         ua_t = T.dot(denoised_x_t, W_x_u) + T.dot(htop_t, W_h_u) + T.dot(u_tm1, W_u_u) + recurrent_bias
            ua_t = T.dot(x_t, self.W_x_u) + T.dot(u_tm1, self.W_u_u) + self.recurrent_bias
            u_t = self.recurrent_hidden_activation(ua_t)
            return None if generate else [ua_t, u_t, h_t]
        
        log.maybeLog(self.logger, "\nCreating recurrent step scan.")
        # For training, the deterministic recurrence is used to compute all the
        # {h_t, 1 <= t <= T} given Xs. Conditional GSNs can then be trained
        # in batches using those parameters.
        u0 = T.zeros((self.recurrent_hidden_size,))  # initial value for the RNN hidden units
        (ua, u, h_t), updates_recurrent = theano.scan(fn=lambda x_t, u_tm1, *_: recurrent_step(x_t, u_tm1, True),
                                                           sequences=self.Xs,
                                                           outputs_info=[None, u0, None],
                                                           non_sequences=self.params)
        
        log.maybeLog(self.logger, "Now for reconstruction sample without noise")
        (_, _, h_t_recon), updates_recurrent_recon = theano.scan(fn=lambda x_t, u_tm1, *_: recurrent_step(x_t, u_tm1, False),
                                                           sequences=self.Xs,
                                                           outputs_info=[None, u0, None],
                                                           non_sequences=self.params)
        # put together the hiddens list
        h_list = [T.zeros_like(self.Xs)]
        for layer, w in enumerate(self.weights_list):
            if layer%2 != 0:
                h_list.append(T.zeros_like(T.dot(h_list[-1], w)))
            else:
                h_list.append((h_t.T[(layer/2)*self.hidden_size:(layer/2+1)*self.hidden_size]).T)
                
        h_list_recon = [T.zeros_like(self.Xs)]
        for layer, w in enumerate(self.weights_list):
            if layer%2 != 0:
                h_list_recon.append(T.zeros_like(T.dot(h_list_recon[-1], w)))
            else:
                h_list_recon.append((h_t_recon.T[(layer/2)*self.hidden_size:(layer/2+1)*self.hidden_size]).T)
        
        #with noise
        _, _, cost, show_cost, error = GSN.build_gsn_given_hiddens(self.Xs, h_list, self.weights_list, self.bias_list, True, self.noiseless_h1, self.hidden_add_noise_sigma, self.input_salt_and_pepper, self.input_sampling, self.MRG, self.visible_activation, self.hidden_activation, self.walkbacks, self.cost_function)
        #without noise for reconstruction
        x_sample_recon, _, _, recon_show_cost, _ = GSN.build_gsn_given_hiddens(self.Xs, h_list_recon, self.weights_list, self.bias_list, False, self.noiseless_h1, self.hidden_add_noise_sigma, self.input_salt_and_pepper, self.input_sampling, self.MRG, self.visible_activation, self.hidden_activation, self.walkbacks, self.cost_function)
        
        updates_train = updates_recurrent
        updates_cost = updates_recurrent
        
        #############
        #   COSTS   #
        #############
        log.maybeLog(self.logger, '\nCost w.r.t p(X|...) at every step in the graph')
        start_functions_time = time.time()

        # if we are not using Hessian-free training create the normal sgd functions
        if not self.hessian_free:
            gradient      = T.grad(cost, self.params)      
            gradient_buffer = [theano.shared(numpy.zeros(param.get_value().shape, dtype='float32')) for param in self.params]
            
            m_gradient    = [self.momentum * gb + (cast32(1) - self.momentum) * g for (gb, g) in zip(gradient_buffer, gradient)]
            param_updates = [(param, param - self.learning_rate * mg) for (param, mg) in zip(self.params, m_gradient)]
            gradient_buffer_updates = zip(gradient_buffer, m_gradient)
                
            updates = OrderedDict(param_updates + gradient_buffer_updates)
            updates_train.update(updates)
        
            log.maybeLog(self.logger, "rnn-gsn learn...")
            self.f_learn = theano.function(inputs  = [self.Xs],
                                      updates = updates_train,
                                      outputs = [show_cost, error],
                                      on_unused_input='warn',
                                      name='rnngsn_f_learn')
            
            log.maybeLog(self.logger, "rnn-gsn cost...")
            self.f_cost  = theano.function(inputs  = [self.Xs],
                                      updates = updates_cost,
                                      outputs = [show_cost, error],
                                      on_unused_input='warn',
                                      name='rnngsn_f_cost')
        
        log.maybeLog(self.logger, "Training/cost functions done.")
        
        # Denoise some numbers : show number, noisy number, predicted number, reconstructed number
        log.maybeLog(self.logger, "Creating graph for noisy reconstruction function at checkpoints during training.")
        self.f_recon = theano.function(inputs=[self.Xs],
                                       outputs=[x_sample_recon[-1], recon_show_cost],
                                       name='rnngsn_f_recon')
        
        # a function to add salt and pepper noise
        self.f_noise = theano.function(inputs = [self.X],
                                       outputs = salt_and_pepper(self.X, self.input_salt_and_pepper),
                                       name='rnngsn_f_noise')
        # Sampling functions
        log.maybeLog(self.logger, "Creating sampling function...")
        if self.layers == 1: 
            self.f_sample = theano.function(inputs = [X_sample],
                                            outputs = visible_pX_chain[-1],
                                            name='rnngsn_f_sample_single_layer')
        else:
            self.f_sample = theano.function(inputs = self.network_state_input,
                                            outputs = self.network_state_output + visible_pX_chain,
                                            on_unused_input='warn',
                                            name='rnngsn_f_sample')
        
    
        log.maybeLog(self.logger, "Done compiling all functions.")
        compilation_time = time.time() - start_functions_time
        # Show the compile time with appropriate easy-to-read units.
        log.maybeLog(self.logger, "Total compilation time took "+make_time_units_string(compilation_time)+".\n\n")
    def __init__(self, train_X=None, train_Y=None, valid_X=None, valid_Y=None, test_X=None, test_Y=None, args=None, logger=None):
        # Output logger
        self.logger = logger
        self.outdir = args.get("output_path", defaults["output_path"])
        if self.outdir[-1] != '/':
            self.outdir = self.outdir+'/'
            
        data.mkdir_p(self.outdir)
        
        # Configuration
        config_filename = self.outdir+'config'
        logger.log('Saving config')
        with open(config_filename, 'w') as f:
            f.write(str(args))
 
        # Input data - make sure it is a list of shared datasets if it isn't. THIS WILL KEEP 'NONE' AS 'NONE' no need to worry :)
        self.train_X = raise_to_list(train_X)
        self.train_Y = raise_to_list(train_Y)
        self.valid_X = raise_to_list(valid_X)
        self.valid_Y = raise_to_list(valid_Y)
        self.test_X  = raise_to_list(test_X)
        self.test_Y  = raise_to_list(test_Y)
                
        # variables from the dataset that are used for initialization and image reconstruction
        if self.train_X is None:
            self.N_input = args.get("input_size")
            if args.get("input_size") is None:
                raise AssertionError("Please either specify input_size in the arguments or provide an example train_X for input dimensionality.")
        else:
            self.N_input = self.train_X[0].get_value(borrow=True).shape[1]
        
        self.is_image = args.get('is_image', defaults['is_image'])
        if self.is_image:
            (_h, _w) = closest_to_square_factors(self.N_input)
            self.image_width  = args.get('width', _w)
            self.image_height = args.get('height', _h)
            
        #######################################
        # Network and training specifications #
        #######################################
        self.layers          = args.get('layers', defaults['layers']) # number hidden layers
        self.walkbacks       = args.get('walkbacks', defaults['walkbacks']) # number of walkbacks
        self.learning_rate   = theano.shared(cast32(args.get('learning_rate', defaults['learning_rate'])))  # learning rate
        self.init_learn_rate = cast32(args.get('learning_rate', defaults['learning_rate']))
        self.momentum        = theano.shared(cast32(args.get('momentum', defaults['momentum']))) # momentum term
        self.annealing       = cast32(args.get('annealing', defaults['annealing'])) # exponential annealing coefficient
        self.noise_annealing = cast32(args.get('noise_annealing', defaults['noise_annealing'])) # exponential noise annealing coefficient
        self.batch_size      = args.get('batch_size', defaults['batch_size'])
        self.gsn_batch_size = args.get('gsn_batch_size', defaults['gsn_batch_size'])
        self.n_epoch         = args.get('n_epoch', defaults['n_epoch'])
        self.early_stop_threshold = args.get('early_stop_threshold', defaults['early_stop_threshold'])
        self.early_stop_length = args.get('early_stop_length', defaults['early_stop_length'])
        self.save_frequency  = args.get('save_frequency', defaults['save_frequency'])
        
        self.noiseless_h1           = args.get('noiseless_h1', defaults["noiseless_h1"])
        self.hidden_add_noise_sigma = theano.shared(cast32(args.get('hidden_add_noise_sigma', defaults["hidden_add_noise_sigma"])))
        self.input_salt_and_pepper  = theano.shared(cast32(args.get('input_salt_and_pepper', defaults["input_salt_and_pepper"])))
        self.input_sampling         = args.get('input_sampling', defaults["input_sampling"])
        self.vis_init               = args.get('vis_init', defaults['vis_init'])
        self.initialize_gsn         = args.get('initialize_gsn', defaults['initialize_gsn'])
        self.hessian_free           = args.get('hessian_free', defaults['hessian_free'])
        
        self.hidden_size = args.get('hidden_size', defaults['hidden_size'])
        self.layer_sizes = [self.N_input] + [self.hidden_size] * self.layers # layer sizes, from h0 to hK (h0 is the visible layer)
        self.recurrent_hidden_size = args.get('recurrent_hidden_size', defaults['recurrent_hidden_size'])
        
        self.f_recon = None
        self.f_noise = None
        
        # Activation functions!
        # For the GSN:
        if args.get('hidden_activation') is not None:
            log.maybeLog(self.logger, 'Using specified activation for GSN hiddens')
            self.hidden_activation = args.get('hidden_activation')
        elif args.get('hidden_act') is not None:
            self.hidden_activation = get_activation_function(args.get('hidden_act'))
            log.maybeLog(self.logger, 'Using {0!s} activation for GSN hiddens'.format(args.get('hidden_act')))
        else:
            log.maybeLog(self.logger, "Using default activation for GSN hiddens")
            self.hidden_activation = defaults['hidden_activation']
            
        # For the RNN:
        if args.get('recurrent_hidden_activation') is not None:
            log.maybeLog(self.logger, 'Using specified activation for RNN hiddens')
            self.recurrent_hidden_activation = args.get('recurrent_hidden_activation')
        elif args.get('recurrent_hidden_act') is not None:
            self.recurrent_hidden_activation = get_activation_function(args.get('recurrent_hidden_act'))
            log.maybeLog(self.logger, 'Using {0!s} activation for RNN hiddens'.format(args.get('recurrent_hidden_act')))
        else:
            log.maybeLog(self.logger, "Using default activation for RNN hiddens")
            self.recurrent_hidden_activation = defaults['recurrent_hidden_activation']
            
        # Visible layer activation
        if args.get('visible_activation') is not None:
            log.maybeLog(self.logger, 'Using specified activation for visible layer')
            self.visible_activation = args.get('visible_activation')
        elif args.get('visible_act') is not None:
            self.visible_activation = get_activation_function(args.get('visible_act'))
            log.maybeLog(self.logger, 'Using {0!s} activation for visible layer'.format(args.get('visible_act')))
        else:
            log.maybeLog(self.logger, 'Using default activation for visible layer')
            self.visible_activation = defaults['visible_activation']
            
        # Cost function!
        if args.get('cost_function') is not None:
            log.maybeLog(self.logger, '\nUsing specified cost function for GSN training\n')
            self.cost_function = args.get('cost_function')
        elif args.get('cost_funct') is not None:
            self.cost_function = get_cost_function(args.get('cost_funct'))
            log.maybeLog(self.logger, 'Using {0!s} for cost function'.format(args.get('cost_funct')))
        else:
            log.maybeLog(self.logger, '\nUsing default cost function for GSN training\n')
            self.cost_function = defaults['cost_function']
        
        ############################
        # Theano variables and RNG #
        ############################
        self.X = T.fmatrix('X') #single (batch) for training gsn
        self.Xs = T.fmatrix('Xs') #sequence for training rnn-gsn
        self.MRG = RNG_MRG.MRG_RandomStreams(1)
        
        ###############
        # Parameters! #
        ###############
        #gsn
        self.weights_list = [get_shared_weights(self.layer_sizes[i], self.layer_sizes[i+1], name="W_{0!s}_{1!s}".format(i,i+1)) for i in range(self.layers)] # initialize each layer to uniform sample from sqrt(6. / (n_in + n_out))
        self.bias_list    = [get_shared_bias(self.layer_sizes[i], name='b_'+str(i)) for i in range(self.layers + 1)] # initialize each layer to 0's.
        
        #recurrent
        self.recurrent_to_gsn_weights_list = [get_shared_weights(self.recurrent_hidden_size, self.layer_sizes[layer], name="W_u_h{0!s}".format(layer)) for layer in range(self.layers+1) if layer%2 != 0]
        self.W_u_u = get_shared_weights(self.recurrent_hidden_size, self.recurrent_hidden_size, name="W_u_u")
        self.W_x_u = get_shared_weights(self.N_input, self.recurrent_hidden_size, name="W_x_u")
        self.recurrent_bias = get_shared_bias(self.recurrent_hidden_size, name='b_u')
        
        #lists for use with gradients
        self.gsn_params = self.weights_list + self.bias_list
        self.u_params   = [self.W_u_u, self.W_x_u, self.recurrent_bias]
        self.params     = self.gsn_params + self.recurrent_to_gsn_weights_list + self.u_params
        
        ###########################################################
        #           load initial parameters of gsn                #
        ###########################################################
        self.train_gsn_first = False
        if self.initialize_gsn:
            params_to_load = 'gsn_params.pkl'
            if not os.path.isfile(params_to_load):
                self.train_gsn_first = True 
            else:
                log.maybeLog(self.logger, "\nLoading existing GSN parameters\n")
                loaded_params = cPickle.load(open(params_to_load,'r'))
                [p.set_value(lp.get_value(borrow=False)) for lp, p in zip(loaded_params[:len(self.weights_list)], self.weights_list)]
                [p.set_value(lp.get_value(borrow=False)) for lp, p in zip(loaded_params[len(self.weights_list):], self.bias_list)]
                
        if self.initialize_gsn:
            self.gsn_args = {'weights_list':       self.weights_list,
                             'bias_list':          self.bias_list,
                             'hidden_activation':  self.hidden_activation,
                             'visible_activation': self.visible_activation,
                             'cost_function':      self.cost_function,
                             'layers':             self.layers,
                             'walkbacks':          self.walkbacks,
                             'hidden_size':        self.hidden_size,
                             'learning_rate':      args.get('learning_rate', defaults['learning_rate']),
                             'momentum':           args.get('momentum', defaults['momentum']),
                             'annealing':          self.annealing,
                             'noise_annealing':    self.noise_annealing,
                             'batch_size':         self.gsn_batch_size,
                             'n_epoch':            self.n_epoch,
                             'early_stop_threshold':   self.early_stop_threshold,
                             'early_stop_length':      self.early_stop_length,
                             'save_frequency':         self.save_frequency,
                             'noiseless_h1':           self.noiseless_h1,
                             'hidden_add_noise_sigma': args.get('hidden_add_noise_sigma', defaults['hidden_add_noise_sigma']),
                             'input_salt_and_pepper':  args.get('input_salt_and_pepper', defaults['input_salt_and_pepper']),
                             'input_sampling':      self.input_sampling,
                             'vis_init':            self.vis_init,
                             'output_path':         self.outdir+'gsn/',
                             'is_image':            self.is_image,
                             'input_size':          self.N_input
                             }
            
        ############
        # Sampling #
        ############
        # the input to the sampling function
        X_sample = T.fmatrix("X_sampling")
        self.network_state_input = [X_sample] + [T.fmatrix("H_sampling_"+str(i+1)) for i in range(self.layers)]
       
        # "Output" state of the network (noisy)
        # initialized with input, then we apply updates
        self.network_state_output = [X_sample] + self.network_state_input[1:]
        visible_pX_chain = []
    
        # ONE update
        _add_noise = True
        log.maybeLog(self.logger, "Performing one walkback in network state sampling.")
        GSN.update_layers(self.network_state_output,
                          self.weights_list,
                          self.bias_list,
                          visible_pX_chain, 
                          _add_noise,
                          self.noiseless_h1,
                          self.hidden_add_noise_sigma,
                          self.input_salt_and_pepper,
                          self.input_sampling,
                          self.MRG,
                          self.visible_activation,
                          self.hidden_activation,
                          self.logger)
    
               
        #############################################
        #      Build the graphs for the RNN-GSN     #
        #############################################
        # If `x_t` is given, deterministic recurrence to compute the u_t. Otherwise, first generate
        def recurrent_step(x_t, u_tm1, add_noise):
            # Make current guess for hiddens based on U
            for i in range(self.layers):
                if i%2 == 0:
                    log.maybeLog(self.logger, "Using {0!s} and {1!s}".format(self.recurrent_to_gsn_weights_list[(i+1)/2],self.bias_list[i+1]))
            h_t = T.concatenate([self.hidden_activation(self.bias_list[i+1] + T.dot(u_tm1, self.recurrent_to_gsn_weights_list[(i+1)/2])) for i in range(self.layers) if i%2 == 0],axis=0)
            
            generate = x_t is None
            if generate:
                pass
            
            # Make a GSN to update U
    #         chain, hs = gsn.build_gsn(x_t, weights_list, bias_list, add_noise, state.noiseless_h1, state.hidden_add_noise_sigma, state.input_salt_and_pepper, state.input_sampling, MRG, visible_activation, hidden_activation, walkbacks, logger)
    #         htop_t = hs[-1]
    #         denoised_x_t = chain[-1]
            # Update U
    #         ua_t = T.dot(denoised_x_t, W_x_u) + T.dot(htop_t, W_h_u) + T.dot(u_tm1, W_u_u) + recurrent_bias
            ua_t = T.dot(x_t, self.W_x_u) + T.dot(u_tm1, self.W_u_u) + self.recurrent_bias
            u_t = self.recurrent_hidden_activation(ua_t)
            return None if generate else [ua_t, u_t, h_t]
        
        log.maybeLog(self.logger, "\nCreating recurrent step scan.")
        # For training, the deterministic recurrence is used to compute all the
        # {h_t, 1 <= t <= T} given Xs. Conditional GSNs can then be trained
        # in batches using those parameters.
        u0 = T.zeros((self.recurrent_hidden_size,))  # initial value for the RNN hidden units
        (ua, u, h_t), updates_recurrent = theano.scan(fn=lambda x_t, u_tm1, *_: recurrent_step(x_t, u_tm1, True),
                                                           sequences=self.Xs,
                                                           outputs_info=[None, u0, None],
                                                           non_sequences=self.params)
        
        log.maybeLog(self.logger, "Now for reconstruction sample without noise")
        (_, _, h_t_recon), updates_recurrent_recon = theano.scan(fn=lambda x_t, u_tm1, *_: recurrent_step(x_t, u_tm1, False),
                                                           sequences=self.Xs,
                                                           outputs_info=[None, u0, None],
                                                           non_sequences=self.params)
        # put together the hiddens list
        h_list = [T.zeros_like(self.Xs)]
        for layer, w in enumerate(self.weights_list):
            if layer%2 != 0:
                h_list.append(T.zeros_like(T.dot(h_list[-1], w)))
            else:
                h_list.append((h_t.T[(layer/2)*self.hidden_size:(layer/2+1)*self.hidden_size]).T)
                
        h_list_recon = [T.zeros_like(self.Xs)]
        for layer, w in enumerate(self.weights_list):
            if layer%2 != 0:
                h_list_recon.append(T.zeros_like(T.dot(h_list_recon[-1], w)))
            else:
                h_list_recon.append((h_t_recon.T[(layer/2)*self.hidden_size:(layer/2+1)*self.hidden_size]).T)
        
        #with noise
        _, _, cost, show_cost, error = GSN.build_gsn_given_hiddens(self.Xs, h_list, self.weights_list, self.bias_list, True, self.noiseless_h1, self.hidden_add_noise_sigma, self.input_salt_and_pepper, self.input_sampling, self.MRG, self.visible_activation, self.hidden_activation, self.walkbacks, self.cost_function)
        #without noise for reconstruction
        x_sample_recon, _, _, recon_show_cost, _ = GSN.build_gsn_given_hiddens(self.Xs, h_list_recon, self.weights_list, self.bias_list, False, self.noiseless_h1, self.hidden_add_noise_sigma, self.input_salt_and_pepper, self.input_sampling, self.MRG, self.visible_activation, self.hidden_activation, self.walkbacks, self.cost_function)
        
        updates_train = updates_recurrent
        updates_cost = updates_recurrent
        
        #############
        #   COSTS   #
        #############
        log.maybeLog(self.logger, '\nCost w.r.t p(X|...) at every step in the graph')
        start_functions_time = time.time()

        # if we are not using Hessian-free training create the normal sgd functions
        if not self.hessian_free:
            gradient      = T.grad(cost, self.params)      
            gradient_buffer = [theano.shared(numpy.zeros(param.get_value().shape, dtype='float32')) for param in self.params]
            
            m_gradient    = [self.momentum * gb + (cast32(1) - self.momentum) * g for (gb, g) in zip(gradient_buffer, gradient)]
            param_updates = [(param, param - self.learning_rate * mg) for (param, mg) in zip(self.params, m_gradient)]
            gradient_buffer_updates = zip(gradient_buffer, m_gradient)
                
            updates = OrderedDict(param_updates + gradient_buffer_updates)
            updates_train.update(updates)
        
            log.maybeLog(self.logger, "rnn-gsn learn...")
            self.f_learn = theano.function(inputs  = [self.Xs],
                                      updates = updates_train,
                                      outputs = [show_cost, error],
                                      on_unused_input='warn',
                                      name='rnngsn_f_learn')
            
            log.maybeLog(self.logger, "rnn-gsn cost...")
            self.f_cost  = theano.function(inputs  = [self.Xs],
                                      updates = updates_cost,
                                      outputs = [show_cost, error],
                                      on_unused_input='warn',
                                      name='rnngsn_f_cost')
        
        log.maybeLog(self.logger, "Training/cost functions done.")
        
        # Denoise some numbers : show number, noisy number, predicted number, reconstructed number
        log.maybeLog(self.logger, "Creating graph for noisy reconstruction function at checkpoints during training.")
        self.f_recon = theano.function(inputs=[self.Xs],
                                       outputs=[x_sample_recon[-1], recon_show_cost],
                                       name='rnngsn_f_recon')
        
        # a function to add salt and pepper noise
        self.f_noise = theano.function(inputs = [self.X],
                                       outputs = salt_and_pepper(self.X, self.input_salt_and_pepper),
                                       name='rnngsn_f_noise')
        # Sampling functions
        log.maybeLog(self.logger, "Creating sampling function...")
        if self.layers == 1: 
            self.f_sample = theano.function(inputs = [X_sample],
                                            outputs = visible_pX_chain[-1],
                                            name='rnngsn_f_sample_single_layer')
        else:
            self.f_sample = theano.function(inputs = self.network_state_input,
                                            outputs = self.network_state_output + visible_pX_chain,
                                            on_unused_input='warn',
                                            name='rnngsn_f_sample')
        
    
        log.maybeLog(self.logger, "Done compiling all functions.")
        compilation_time = time.time() - start_functions_time
        # Show the compile time with appropriate easy-to-read units.
        log.maybeLog(self.logger, "Total compilation time took "+make_time_units_string(compilation_time)+".\n\n")