Package mdp :: Package nodes :: Class TimeDelayNode

Class TimeDelayNode

Copy delayed version of the input signal on the space dimensions.

For example, for time_frames=3 and gap=2:

[ X(1) Y(1)        [ X(1) Y(1)   0    0    0    0
  X(2) Y(2)          X(2) Y(2)   0    0    0    0
  X(3) Y(3)   -->    X(3) Y(3) X(1) Y(1)   0    0
  X(4) Y(4)          X(4) Y(4) X(2) Y(2)   0    0
  X(5) Y(5)          X(5) Y(5) X(3) Y(3) X(1) Y(1)
  X(6) Y(6)          ...  ...  ...  ...  ...  ... ]
  X(7) Y(7)
  X(8) Y(8)
  ...  ...  ]

This node provides similar functionality as the TimeFramesNode, only that it performs a time embedding into the past rather than into the future.

See TimeDelaySlidingWindowNode for a sliding window delay node for application in a non-batch manner.

Original code contributed by Sebastian Hoefer. Dec 31, 2010

Instance Methods

[hide private]

__init__(self, time_frames, gap=1, input_dim=None, dtype=None)
Initializes an object of type 'TimeDelayNode'.

_execute(self, x)

execute(self, x)
Process the data contained in x.

numpy.ndarray

pseudo_inverse(self, y)
This function returns a pseudo-inverse of the execute frame.

Inherited from unreachable.newobject: __long__, __native__, __nonzero__, __unicode__, next

Inherited from object: __delattr__, __format__, __getattribute__, __hash__, __new__, __reduce__, __reduce_ex__, __setattr__, __sizeof__, __subclasshook__

Inherited from TimeFramesNode

list

_get_supported_dtypes(self)
Return the data types supported by this node.

_set_input_dim(self, n)

_set_output_dim(self, n)

Inherited from Node

__add__(self, other)

__call__(self, x, *args, **kwargs)
Calling an instance of Node is equivalent to calling its execute method.

__repr__(self)
repr(x)

__str__(self)
str(x)

_check_input(self, x)

_check_output(self, y)

_check_train_args(self, x, *args, **kwargs)

_get_train_seq(self)

_if_training_stop_training(self)

_inverse(self, x)

_pre_execution_checks(self, x)
This method contains all pre-execution checks.

_pre_inversion_checks(self, y)
This method contains all pre-inversion checks.

_refcast(self, x)
Helper function to cast arrays to the internal dtype.

_set_dtype(self, t)

_stop_training(self, *args, **kwargs)

_train(self, x)

copy(self, protocol=None)
Return a deep copy of the node.

get_current_train_phase(self)
Return the index of the current training phase.

get_dtype(self)
Return dtype.

get_input_dim(self)
Return input dimensions.

get_output_dim(self)
Return output dimensions.

get_remaining_train_phase(self)
Return the number of training phases still to accomplish.

get_supported_dtypes(self)
Return dtypes supported by the node as a list of numpy.dtype objects.

has_multiple_training_phases(self)
Return True if the node has multiple training phases.

inverse(self, y, *args, **kwargs)
Invert y.

is_training(self)
Return True if the node is in the training phase, False otherwise.

save(self, filename, protocol=-1)
Save a pickled serialization of the node to filename. If filename is None, return a string.

set_dtype(self, t)
Set internal structures' dtype.

set_input_dim(self, n)
Set input dimensions.

set_output_dim(self, n)
Set output dimensions.

stop_training(self, *args, **kwargs)
Stop the training phase.

train(self, x, *args, **kwargs)
Update the internal structures according to the input data x.

Static Methods

[hide private]

Inherited from TimeFramesNode

is_invertible()
Return True if the node can be inverted, False otherwise.

is_trainable()
Return True if the node can be trained, False otherwise.

Properties

[hide private]

Inherited from object: __class__

Inherited from Node

_train_seq
List of tuples:

dtype
dtype

input_dim
Input dimensions

output_dim
Output dimensions

supported_dtypes
Supported dtypes

Method Details

[hide private]

init(self, time_frames, gap=1, input_dim=None, dtype=None)
(Constructor)

Initializes an object of type 'TimeDelayNode'.

Parameters:

time_frames (int) - Number of delayed copies.
gap (int) - Time delay between the copies.
input_dim (int) - The input dimensionality.
dtype (numpy.dtype) - The datatype.

Overrides: object.__init__

_execute(self, x)

Overrides: Node._execute

execute(self, x)

Process the data contained in x.

If the object is still in the training phase, the function stop_training will be called. x is a matrix having different variables on different columns and observations on the rows.

By default, subclasses should overwrite _execute to implement their execution phase. The docstring of the _execute method overwrites this docstring.

Overrides: Node.execute

pseudo_inverse(self, y)

This function returns a pseudo-inverse of the execute frame.

y == execute(x) is only True if y belongs to the domain of execute and has been computed with a sufficently large x. If gap > 1 some of the last rows will be filled with zeros.

Parameters:

y - The execute frame.

Returns: numpy.ndarray

A pseudo-inverse of the given frame.

Raises:

mdp.NodeException - When called. This method overrides the corresponding method of the ``TimeFramesNode*.

Overrides: TimeFramesNode.pseudo_inverse

Class TimeDelayNode

__init__(self, time_frames, gap=1, input_dim=None, dtype=None) (Constructor)

_execute(self, x)

execute(self, x)

pseudo_inverse(self, y)

init(self, time_frames, gap=1, input_dim=None, dtype=None)
(Constructor)