Ejemplo n.º 1
0
    def __init__(self, conf, dataconf, model):
        '''Evaluator constructor

        Args:
            conf: the evaluator configuration as a ConfigParser
            dataconf: the database configuration
            model: the model to be evaluated
        '''

        super(LossEvaluator, self).__init__(conf, dataconf, model)
        self.loss_computer = loss_computer_factory.factory(
            conf.get('evaluator',
                     'loss_type'))(int(conf.get('evaluator', 'batch_size')))
Ejemplo n.º 2
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    def __init__(self, conf, dataconf, models, task):
        '''TaskLossEvaluator constructor

        Args:
            conf: the evaluator configuration as a ConfigParser
            dataconf: the database configuration
            models: the models to be evaluated
            task: the name of the task being evaluated
        '''


        super(TaskLossEvaluator, self).__init__(conf, dataconf, models, task)
        self.loss_computer = loss_computer_factory.factory(
		conf.get(task,'loss_type'))(self.batch_size)
Ejemplo n.º 3
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    def __init__(self, conf, dataconf, lossconf, models, task):
        """TaskLossEvaluator constructor

		Args:
			conf: the evaluator configuration as a ConfigParser
			dataconf: the database configuration
			lossconf: a configuration for the loss function
			models: the models to be evaluated
			task: the name of the task being evaluated
		"""

        super(TaskLossEvaluator, self).__init__(conf, dataconf, models, task)

        if lossconf:
            loss_type = lossconf['loss_type']
        else:
            loss_type = conf.get(task, 'loss_type')
        self.loss_computer = loss_computer_factory.factory(loss_type)(
            lossconf, self.batch_size)
Ejemplo n.º 4
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    def __init__(self, conf, tasksconf, dataconf, modelconf, evaluatorconf,
                 expdir, init_filename, server, task_index):
        '''
        NnetTrainer constructor, creates the training graph

        Args:
            conf: the trainer config
            taskconf: the config file for each task
            dataconf: the data configuration as a ConfigParser
            modelconf: the neural net model configuration
            evaluatorconf: the evaluator configuration for evaluating
                if None no evaluation will be done
            expdir: directory where the summaries will be written
            init_filename: filename of the network that should be used to
            initialize the model. Put to None if no network is available/wanted.
            server: optional server to be used for distributed training
            task_index: optional index of the worker task in the cluster
        '''

        self.expdir = expdir
        self.server = server
        self.conf = conf
        self.tasksconf = tasksconf
        self.task_index = task_index
        self.init_filename = init_filename

        self.batch_size = int(conf['batch_size'])

        cluster = tf.train.ClusterSpec(server.server_def.cluster)

        #create the graph
        self.graph = tf.Graph()

        #3 model types for multi task: single one to one; single one to many; multiple one to one
        #single one to one: the whole model is shared for all tasks, only loss function can be different
        #single one to many: each task has a separate output so only part of the network is shared, eg evrything but the output layer
        #multiple one to one: each task has its own network. Possibly the outputs are combined in a loss function

        #create the model
        modelfile = os.path.join(expdir, 'model', 'model.pkl')
        with open(modelfile, 'wb') as fid:
            self.model = model_factory.factory(
                modelconf.get('model', 'architecture'))(conf=modelconf)
            pickle.dump(self.model, fid)

        evaltype = evaluatorconf.get('evaluator', 'evaluator')

        #get the database configurations
        input_dataconfs = dict()
        target_dataconfs = dict()
        loss_computers = dict()
        nr_input_sections = dict()
        if evaltype != 'None':
            evaluators = dict()

        for task in self.conf['tasks'].split(' '):
            taskconf = self.tasksconf[task]

            #get the database configurations
            input_names = modelconf.get('io', 'inputs').split(' ')
            if input_names == ['']:
                input_names = []
            input_sections = [taskconf[i].split(' ') for i in input_names]
            nr_input_sections[task] = len(input_sections)
            task_input_dataconfs = []
            for sectionset in input_sections:
                task_input_dataconfs.append([])
                for section in sectionset:
                    task_input_dataconfs[-1].append(
                        dict(dataconf.items(section)))
            input_dataconfs[task] = task_input_dataconfs

            output_names = taskconf['targets'].split(' ')
            if output_names == ['']:
                output_names = []
            target_sections = [taskconf[o].split(' ') for o in output_names]
            task_target_dataconfs = []
            for sectionset in target_sections:
                task_target_dataconfs.append([])
                for section in sectionset:
                    task_target_dataconfs[-1].append(
                        dict(dataconf.items(section)))
            target_dataconfs[task] = task_target_dataconfs

            #create the loss computer
            loss_computer = loss_computer_factory.factory(
                taskconf['loss_type'])(self.batch_size)

            loss_computers[task] = loss_computer

            if evaltype != 'None':
                evaluator = evaluator_factory.factory(evaltype)(
                    conf=evaluatorconf,
                    dataconf=dataconf,
                    model=self.model,
                    task=task)

                evaluators[task] = evaluator

        if 'local' in cluster.as_dict():
            num_replicas = 1
            device = tf.DeviceSpec(job='local')
        else:
            #distributed training
            num_replicas = len(cluster.as_dict()['worker'])
            num_servers = len(cluster.as_dict()['ps'])
            ps_strategy = tf.contrib.training.GreedyLoadBalancingStrategy(
                num_tasks=num_servers,
                load_fn=tf.contrib.training.byte_size_load_fn)
            device = tf.train.replica_device_setter(ps_tasks=num_servers,
                                                    ps_strategy=ps_strategy)
            chief_ps = tf.DeviceSpec(job='ps', task=0)

        self.is_chief = task_index == 0

        #define the placeholders in the graph
        with self.graph.as_default():

            #create a local num_steps variable
            self.num_steps = tf.get_variable(
                name='num_steps',
                shape=[],
                dtype=tf.int32,
                initializer=tf.constant_initializer(0),
                trainable=False)

            #a variable to hold the amount of steps already taken
            self.global_step = tf.get_variable(
                name='global_step',
                shape=[],
                dtype=tf.int32,
                initializer=tf.constant_initializer(0),
                trainable=False)

            should_terminate = tf.get_variable(
                name='should_terminate',
                shape=[],
                dtype=tf.bool,
                initializer=tf.constant_initializer(False),
                trainable=False)

            self.terminate = should_terminate.assign(True).op

            #create a check if training should continue
            self.should_stop = tf.logical_or(
                tf.greater_equal(self.global_step, self.num_steps),
                should_terminate)

            with tf.device(device):
                data_queues = dict()
                num_steps = []
                done_ops = []
                for task in self.conf['tasks'].split(' '):

                    #check if running in distributed model
                    if 'local' in cluster.as_dict():

                        #get the filenames
                        data_queue_elements, _ = input_pipeline.get_filenames(
                            input_dataconfs[task] + target_dataconfs[task])

                        #create the data queue and queue runners (inputs get shuffled! I already did this so set to False)
                        data_queue = tf.train.string_input_producer(
                            string_tensor=data_queue_elements,
                            shuffle=False,
                            seed=None,
                            capacity=self.batch_size * 2,
                            shared_name='data_queue_' + task)

                        data_queues[task] = data_queue

                        #compute the number of steps
                        if int(conf['numbatches_to_aggregate']) == 0:
                            task_num_steps = (int(conf['num_epochs']) *
                                              len(data_queue_elements) /
                                              self.batch_size)
                        else:
                            task_num_steps = (
                                int(conf['num_epochs']) *
                                len(data_queue_elements) /
                                (self.batch_size *
                                 int(conf['numbatches_to_aggregate'])))

                        #set the number of steps
                        num_steps.append(task_num_steps)
                        done_ops.append(tf.no_op())

                    else:
                        with tf.device(chief_ps):

                            #get the data queue
                            data_queue = tf.FIFOQueue(
                                capacity=self.batch_size * (num_replicas + 1),
                                shared_name='data_queue_' + task,
                                name='data_queue_' + task,
                                dtypes=[tf.string],
                                shapes=[[]])

                            data_queues[task] = data_queue

                            #get the number of steps from the parameter server
                            num_steps_queue = tf.FIFOQueue(
                                capacity=num_replicas,
                                dtypes=[tf.int32],
                                shared_name='num_steps_queue',
                                name='num_steps_queue',
                                shapes=[[]])

                            #set the number of steps
                            task_num_steps = num_steps_queue.dequeue()

                        #get the done queues
                        for i in range(num_servers):
                            with tf.device('job:ps/task:%d' % i):
                                done_queue = tf.FIFOQueue(
                                    capacity=num_replicas,
                                    dtypes=[tf.bool],
                                    shapes=[[]],
                                    shared_name='done_queue%d' % i,
                                    name='done_queue%d' % i)

                                done_ops.append(done_queue.enqueue(True))

                self.set_num_steps = self.num_steps.assign(min(num_steps)).op
                self.done = tf.group(*done_ops)

                #training part
                with tf.variable_scope('train'):

                    #a variable to scale the learning rate (used to reduce the
                    #learning rate in case validation performance drops)
                    learning_rate_fact = tf.get_variable(
                        name='learning_rate_fact',
                        shape=[],
                        initializer=tf.constant_initializer(1.0),
                        trainable=False)

                    #compute the learning rate with exponential decay and scale
                    #with the learning rate factor
                    self.learning_rate = (tf.train.exponential_decay(
                        learning_rate=float(conf['initial_learning_rate']),
                        global_step=self.global_step,
                        decay_steps=self.num_steps,
                        decay_rate=float(conf['learning_rate_decay'])) *
                                          learning_rate_fact)

                    #create the optimizer
                    optimizer = tf.train.AdamOptimizer(self.learning_rate)

                    self.total_loss = tf.get_variable(
                        name='total_loss',
                        shape=[],
                        dtype=tf.float32,
                        initializer=tf.constant_initializer(0),
                        trainable=False)

                    self.reset_loss = self.total_loss.assign(0.0)

                    loss = []

                    for task in self.conf['tasks'].split(' '):

                        with tf.variable_scope(task):

                            #create the input pipeline
                            data, seq_length = input_pipeline.input_pipeline(
                                data_queue=data_queues[task],
                                batch_size=self.batch_size,
                                numbuckets=int(conf['numbuckets']),
                                dataconfs=input_dataconfs[task] +
                                target_dataconfs[task])

                            inputs = {
                                input_names[i]: d
                                for i, d in enumerate(
                                    data[:nr_input_sections[task]])
                            }
                            seq_length = {
                                input_names[i]: d
                                for i, d in enumerate(
                                    seq_length[:nr_input_sections[task]])
                            }
                            targets = {
                                output_names[i]: d
                                for i, d in enumerate(
                                    data[nr_input_sections[task]:])
                            }
                            #target_seq_length = {
                            #output_names[i]: d
                            #for i, d in enumerate(seq_length[nr_input_sections[task]:])}

                            #compute the training outputs of the model
                            logits = self.model(inputs=inputs,
                                                input_seq_length=seq_length,
                                                is_training=True)

                            #TODO: The proper way to exploit data paralellism is via the
                            #SyncReplicasOptimizer defined below. However for some reason it hangs
                            #and I have not yet found a solution for it. For the moment the gradients
                            #are accumulated in a way that does not allow data paralellism and there
                            # is no advantage on having multiple workers. (We also accumulate the loss)

                            #create an optimizer that aggregates gradients
                            #if int(conf['numbatches_to_aggregate']) > 0:
                            #optimizer = tf.train.SyncReplicasOptimizer(
                            #opt=optimizer,
                            #replicas_to_aggregate=int(
                            #conf['numbatches_to_aggregate'])#,
                            ##total_num_replicas=num_replicas
                            #)

                            #compute the loss
                            task_loss = loss_computers[task](targets, logits,
                                                             seq_length)

                            #append the task loss to the global loss
                            loss.append(task_loss)

                #accumulate losses from tasks
                    with tf.variable_scope('accumulate_loss_from_tasks'):
                        loss = tf.reduce_mean(loss)

                #accumulate losses from batches
                    self.acc_loss = self.total_loss.assign_add(loss)

                    ##compute the gradients
                    #grads_and_vars = optimizer.compute_gradients(self.loss)

                    #with tf.variable_scope('clip'):
                    #clip_value = float(conf['clip_grad_value'])
                    ##clip the gradients
                    #grads_and_vars = [(tf.clip_by_value(grad, -clip_value, clip_value), var)
                    #for grad, var in grads_and_vars]

                    self.params = tf.trainable_variables()

                    grads = [
                        tf.get_variable(param.op.name,
                                        param.get_shape().as_list(),
                                        initializer=tf.constant_initializer(0),
                                        trainable=False)
                        for param in self.params
                    ]

                    self.reset_grad = tf.variables_initializer(grads)

                    #compute the gradients
                    minibatch_grads_and_vars = optimizer.compute_gradients(
                        loss)

                    with tf.variable_scope('clip'):
                        clip_value = float(conf['clip_grad_value'])
                        #clip the gradients
                        minibatch_grads_and_vars = [
                            (tf.clip_by_value(grad, -clip_value,
                                              clip_value), var)
                            for grad, var in minibatch_grads_and_vars
                        ]

                    (minibatchgrads,
                     minibatchvars) = zip(*minibatch_grads_and_vars)

                    #update gradients by accumulating them
                    self.update_gradients = [
                        grad.assign_add(batchgrad)
                        for batchgrad, grad in zip(minibatchgrads, grads)
                    ]

                    #opperation to apply the gradients
                    grads_and_vars = list(zip(grads, minibatchvars))
                    apply_gradients_op = optimizer.apply_gradients(
                        grads_and_vars=grads_and_vars,
                        global_step=self.global_step,
                        name='apply_gradients')

                    #all remaining operations with the UPDATE_OPS GraphKeys
                    update_ops = tf.get_collection(tf.GraphKeys.UPDATE_OPS)

                    #create an operation to update the gradients, the batch_loss
                    #and do all other update ops
                    self.update_op = tf.group(*([apply_gradients_op] +
                                                update_ops),
                                              name='update')

                if evaltype != 'None':

                    #validation part
                    with tf.variable_scope('validate'):

                        #create a variable to hold the validation loss
                        self.validation_loss = tf.get_variable(
                            name='validation_loss',
                            shape=[],
                            dtype=tf.float32,
                            initializer=tf.constant_initializer(0),
                            trainable=False)

                        #create a variable to save the last step where the model
                        #was validated
                        validated_step = tf.get_variable(
                            name='validated_step',
                            shape=[],
                            dtype=tf.int32,
                            initializer=tf.constant_initializer(
                                -int(conf['valid_frequency'])),
                            trainable=False)

                        #a check if validation is due
                        self.should_validate = tf.greater_equal(
                            self.global_step - validated_step,
                            int(conf['valid_frequency']))

                        val_batch_loss = []
                        valbatches = []

                        for task in self.conf['tasks'].split(' '):

                            with tf.variable_scope(task):

                                task_val_batch_loss, task_valbatches, _, _ = evaluators[
                                    task].evaluate()
                                val_batch_loss.append(task_val_batch_loss)
                                valbatches.append(task_valbatches)

                        val_batch_loss = tf.reduce_mean(val_batch_loss)
                        self.valbatches = min(valbatches)

                        self.update_loss = self.validation_loss.assign(
                            self.validation_loss +
                            val_batch_loss  #/self.valbatches
                        ).op

                        #update the learning rate factor
                        self.half_lr = learning_rate_fact.assign(
                            learning_rate_fact / 2).op

                        #create an operation to updated the validated step
                        self.update_validated_step = validated_step.assign(
                            self.global_step).op

                        #variable to hold the best validation loss so far
                        self.best_validation = tf.get_variable(
                            name='best_validation',
                            shape=[],
                            dtype=tf.float32,
                            initializer=tf.constant_initializer(1.79e+308),
                            trainable=False)

                        #op to update the best velidation loss
                        self.update_best = self.best_validation.assign(
                            self.validation_loss).op

                        #a variable that holds the amount of workers at the
                        #validation point
                        waiting_workers = tf.get_variable(
                            name='waiting_workers',
                            shape=[],
                            dtype=tf.int32,
                            initializer=tf.constant_initializer(0),
                            trainable=False)

                        #an operation to signal a waiting worker
                        self.waiting = waiting_workers.assign_add(1).op

                        #an operation to set the waiting workers to zero
                        self.reset_waiting = waiting_workers.initializer

                        #an operation to check if all workers are waiting
                        self.all_waiting = tf.equal(waiting_workers,
                                                    num_replicas - 1)

                        tf.summary.scalar('validation loss',
                                          self.validation_loss)

                else:
                    self.update_loss = None

                tf.summary.scalar('learning rate', self.learning_rate)

                #create a histogram for all trainable parameters
                for param in tf.trainable_variables():
                    tf.summary.histogram(param.name, param)

                #create the scaffold
                self.scaffold = tf.train.Scaffold()
Ejemplo n.º 5
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    def __init__(self, task_name, trainerconf, taskconf, models, modelconf,
                 dataconf, evaluatorconf, lossconf, batch_size):
        """
		TaskTrainer constructor, gathers the dataconfigs and sets the loss_computer and
		evaluator for this task.

		Args:
		task_name: a name for the training task
			trainerconf: the trainer config
			taskconf: the config file for each task
			models: the neural net models
			modelconf: the neural net models configuration
			dataconf: the data configuration as a ConfigParser
			evaluatorconf: the evaluator configuration for evaluating
				if None no evaluation will be done
			lossconf: the configuration of the loss function
			batch_size: the size of the batch.
		"""

        self.task_name = task_name
        self.trainerconf = trainerconf
        self.taskconf = taskconf
        self.models = models
        self.modelconf = modelconf
        self.evaluatorconf = evaluatorconf
        self.batch_size = batch_size

        # get the database configurations for all inputs, outputs, intermediate model nodes and models.
        self.output_names = taskconf['outputs'].split(' ')
        self.input_names = taskconf['inputs'].split(' ')
        self.target_names = taskconf['targets'].split(' ')
        if self.target_names == ['']:
            self.target_names = []
        self.model_nodes = taskconf['nodes'].split(' ')

        if 'linkedsets' in taskconf:
            set_names = taskconf['linkedsets'].split(' ')
            self.linkedsets = dict()
            for set_name in set_names:
                set_input_names = [
                    '%s_%s' % (set_name, in_name)
                    for in_name in self.input_names
                ]
                set_target_names = [
                    '%s_%s' % (set_name, tar_name)
                    for tar_name in self.target_names
                ]
                self.linkedsets[set_name] = {
                    'inputs': set_input_names,
                    'targets': set_target_names
                }

            if 'linkedset_weighting' in taskconf:
                linkedset_weighting = np.array(
                    map(float, taskconf['linkedset_weighting'].split(' ')))
                # the first set has the reference weight
                linkedset_weighting /= linkedset_weighting[0]
            else:
                linkedset_weighting = np.array([1.0] * len(self.linkedsets))
            self.linkedset_weighting = {
                set_name: weight
                for set_name, weight in zip(set_names, linkedset_weighting)
            }
        else:
            self.linkedsets = {
                'set0': {
                    'inputs': self.input_names,
                    'targets': self.target_names
                }
            }
            self.linkedset_weighting = {'set0': 1.0}

        self.input_dataconfs = dict()
        self.target_dataconfs = dict()
        for linkedset in self.linkedsets:
            self.input_dataconfs[linkedset] = []
            for input_name in self.linkedsets[linkedset]['inputs']:
                # input config
                dataconfs_for_input = []
                sections = taskconf[input_name].split(' ')
                for section in sections:
                    dataconfs_for_input.append(dict(dataconf.items(section)))
                self.input_dataconfs[linkedset].append(dataconfs_for_input)

            self.target_dataconfs[linkedset] = []
            for target_name in self.linkedsets[linkedset]['targets']:
                # target config
                dataconfs_for_target = []
                sections = taskconf[target_name].split(' ')
                for section in sections:
                    dataconfs_for_target.append(dict(dataconf.items(section)))
                self.target_dataconfs[linkedset].append(dataconfs_for_target)

        self.model_links = dict()
        self.inputs_links = dict()
        self.nodes_output_names = dict()
        for node in self.model_nodes:
            self.model_links[node] = taskconf['%s_model' % node]
            self.inputs_links[node] = taskconf['%s_inputs' % node].split(' ')
            if '%s_output_names' % node in taskconf:
                self.nodes_output_names[node] = taskconf['%s_output_names' %
                                                         node].split(' ')
            else:
                self.nodes_output_names[node] = node

        # create the loss computer
        if lossconf:
            loss_type = lossconf['loss_type']
        else:
            loss_type = taskconf['loss_type']

        self.loss_computer = loss_computer_factory.factory(loss_type)(
            lossconf, self.batch_size)

        # create valiation evaluator
        evaltype = evaluatorconf.get('evaluator', 'evaluator')
        if evaltype != 'None':
            self.evaluator = evaluator_factory.factory(evaltype)(
                conf=evaluatorconf,
                dataconf=dataconf,
                lossconf=lossconf,
                models=self.models,
                task=task_name)
Ejemplo n.º 6
0
    def __init__(self, task_name, trainerconf, taskconf, models, modelconf,
                 dataconf, evaluatorconf, batch_size):
        """
		TaskTrainer constructor, gathers the dataconfigs and sets the loss_computer and
		evaluator for this task.

		Args:
		task_name: a name for the training task
			trainerconf: the trainer config
			taskconf: the config file for each task
			models: the neural net models
			modelconf: the neural net models configuration
			dataconf: the data configuration as a ConfigParser
			evaluatorconf: the evaluator configuration for evaluating
				if None no evaluation will be done
			batch_size: the size of the batch.
		"""

        self.task_name = task_name
        self.trainerconf = trainerconf
        self.taskconf = taskconf
        self.models = models
        self.modelconf = modelconf
        self.evaluatorconf = evaluatorconf
        self.batch_size = batch_size

        # get the database configurations for all inputs, outputs, intermediate model nodes and models.
        self.output_names = taskconf['outputs'].split(' ')
        self.input_names = taskconf['inputs'].split(' ')
        self.target_names = taskconf['targets'].split(' ')
        if self.target_names == ['']:
            self.target_names = []
        self.model_nodes = taskconf['nodes'].split(' ')

        if 'linkedsets' in taskconf:
            set_names = taskconf['linkedsets'].split(' ')
            self.linkedsets = dict()
            for set_name in set_names:
                inp_indices = map(int,
                                  taskconf['%s_inputs' % set_name].split(' '))
                tar_indices = map(int,
                                  taskconf['%s_targets' % set_name].split(' '))
                set_inputs = [
                    inp for ind, inp in enumerate(self.input_names)
                    if ind in inp_indices
                ]
                set_targets = [
                    tar for ind, tar in enumerate(self.target_names)
                    if ind in tar_indices
                ]
                self.linkedsets[set_name] = {
                    'inputs': set_inputs,
                    'targets': set_targets
                }
        else:
            self.linkedsets = {
                'set0': {
                    'inputs': self.input_names,
                    'targets': self.target_names
                }
            }

        self.input_dataconfs = dict()
        self.target_dataconfs = dict()
        for linkedset in self.linkedsets:
            self.input_dataconfs[linkedset] = []
            for input_name in self.linkedsets[linkedset]['inputs']:
                # input config
                dataconfs_for_input = []
                sections = taskconf[input_name].split(' ')
                for section in sections:
                    dataconfs_for_input.append(dict(dataconf.items(section)))
                self.input_dataconfs[linkedset].append(dataconfs_for_input)

            self.target_dataconfs[linkedset] = []
            for target_name in self.linkedsets[linkedset]['targets']:
                # target config
                dataconfs_for_target = []
                sections = taskconf[target_name].split(' ')
                for section in sections:
                    dataconfs_for_target.append(dict(dataconf.items(section)))
                self.target_dataconfs[linkedset].append(dataconfs_for_target)

        self.model_links = dict()
        self.inputs_links = dict()
        for node in self.model_nodes:
            self.model_links[node] = taskconf['%s_model' % node]
            self.inputs_links[node] = taskconf['%s_inputs' % node].split(' ')

        # create the loss computer
        self.loss_computer = loss_computer_factory.factory(
            taskconf['loss_type'])(self.batch_size)

        # create valiation evaluator
        evaltype = evaluatorconf.get('evaluator', 'evaluator')
        if evaltype != 'None':
            self.evaluator = evaluator_factory.factory(evaltype)(
                conf=evaluatorconf,
                dataconf=dataconf,
                models=self.models,
                task=task_name)
Ejemplo n.º 7
0
    def __init__(self, task_name, trainerconf, taskconf, models, modelconf,
                 dataconf, evaluatorconf, batch_size):
        '''
        TaskTrainer constructor, gathers the dataconfigs and sets the loss_computer and
        evaluator for this task.

        Args:
	    task_name: a name for the training task
            trainerconf: the trainer config
            taskconf: the config file for each task
            models: the neural net models
            modelconf: the neural net models configuration
            dataconf: the data configuration as a ConfigParser
            evaluatorconf: the evaluator configuration for evaluating
                if None no evaluation will be done
            batch_size: the size of the batch.
        '''

        self.task_name = task_name
        self.trainerconf = trainerconf
        self.taskconf = taskconf
        self.models = models
        self.modelconf = modelconf
        self.evaluatorconf = evaluatorconf
        self.batch_size = batch_size

        #get the database configurations for all inputs, outputs, intermediate model nodes and models.
        self.output_names = taskconf['outputs'].split(' ')
        self.input_names = taskconf['inputs'].split(' ')
        self.model_nodes = taskconf['nodes'].split(' ')
        self.input_dataconfs = []
        for input_name in self.input_names:
            #input config
            self.input_dataconfs.append(
                dict(dataconf.items(taskconf[input_name])))

        self.target_names = taskconf['targets'].split(' ')
        if self.target_names == ['']:
            self.target_names = []
        self.target_dataconfs = []
        for target_name in self.target_names:
            #target config
            self.target_dataconfs.append(
                dict(dataconf.items(taskconf[target_name])))

        self.model_links = dict()
        self.inputs_links = dict()
        for node in self.model_nodes:
            self.model_links[node] = taskconf['%s_model' % node]
            self.inputs_links[node] = taskconf['%s_inputs' % node].split(' ')

    #create the loss computer
        self.loss_computer = loss_computer_factory.factory(
            taskconf['loss_type'])(self.batch_size)

        #create valiation evaluator
        evaltype = evaluatorconf.get('evaluator', 'evaluator')
        if evaltype != 'None':
            self.evaluator = evaluator_factory.factory(evaltype)(
                conf=evaluatorconf,
                dataconf=dataconf,
                models=self.models,
                task=task_name)