Get an input signal, expand it in the space of
inhomogeneous polynomials of degree 2 and extract its slowly varying
components. The get_quadratic_form method returns the input-output
function of one of the learned unit as a QuadraticForm object.
See the documentation of mdp.utils.QuadraticForm for additional
information.
More information about Slow Feature Analysis can be found in
Wiskott, L. and Sejnowski, T.J., Slow Feature Analysis: Unsupervised
Learning of Invariances, Neural Computation, 14(4):715-770 (2002).
|
|
__init__(self,
input_dim=None,
output_dim=None,
dtype=None,
include_last_sample=True)
For the include_last_sample switch have a look at the
SFANode class docstring. |
|
|
|
|
_execute(self,
x,
n=None)
Compute the output of the slowest functions.
If 'n' is an integer, then use the first 'n' slowest components. |
|
|
|
|
|
|
|
|
|
|
|
|
|
_train(self,
x,
include_last_sample=None)
For the include_last_sample switch have a look at the
SFANode class docstring. |
|
|
|
|
execute(self,
x,
n=None)
Compute the output of the slowest functions.
If 'n' is an integer, then use the first 'n' slowest components. |
|
|
|
|
get_quadratic_form(self,
nr)
Return the matrix H, the vector f and the constant c of the
quadratic form 1/2 x'Hx + f'x + c that defines the output
of the component 'nr' of the SFA node. |
|
|
|
|
|
|
|
train(self,
x,
include_last_sample=None)
For the include_last_sample switch have a look at the
SFANode class docstring. |
|
|
|
Inherited from unreachable.newobject:
__long__,
__native__,
__nonzero__,
__unicode__,
next
Inherited from object:
__delattr__,
__format__,
__getattribute__,
__hash__,
__new__,
__reduce__,
__reduce_ex__,
__setattr__,
__sizeof__,
__subclasshook__
|
|
|
|
|
|
|
|
|
get_eta_values(self,
t=1)
Return the eta values of the slow components learned during
the training phase. If the training phase has not been completed
yet, call stop_training. |
|
|
|
|
|
|
|
time_derivative(self,
x)
Compute the linear approximation of the time derivative. |
|
|
|
|
|
|
|
__call__(self,
x,
*args,
**kwargs)
Calling an instance of Node is equivalent to calling
its execute method. |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
_refcast(self,
x)
Helper function to cast arrays to the internal dtype. |
|
|
|
|
|
|
|
|
|
|
copy(self,
protocol=None)
Return a deep copy of the node. |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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. |
|
|
|
|
|
|
|
|
