Package mdp :: Package nodes :: Class FastICANode
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Class FastICANode



Perform Independent Component Analysis using the FastICA algorithm.
Note that FastICA is a batch-algorithm. This means that it needs
all input data before it can start and compute the ICs.
The algorithm is here given as a Node for convenience, but it
actually accumulates all inputs it receives. Remember that to avoid
running out of memory when you have many components and many time samples.

FastICA does not support the telescope mode (the convergence
criterium is not robust in telescope mode).

Reference:
Aapo Hyvarinen (1999).
Fast and Robust Fixed-Point Algorithms for Independent Component Analysis
IEEE Transactions on Neural Networks, 10(3):626-634.

Internal variables of interest:

  self.white       -- the whitening node used for preprocessing.
  self.filters     -- the ICA filters matrix (this is the transposed of the
                    projection matrix after whitening).
  self.convergence -- the value of the convergence threshold.

History:
- 1.4.1998  created for Matlab by Jarmo Hurri, Hugo Gavert,
            Jaakko Sarela, and Aapo Hyvarinen
- 7.3.2003  modified for Python by Thomas Wendler
- 3.6.2004  rewritten and adapted for scipy and MDP by MDP's authors
- 25.5.2005 now independent from scipy. Requires Numeric or numarray
- 26.6.2006 converted to numpy
- 14.9.2007 updated to Matlab version 2.5 

Nested Classes [hide private]
    Inherited from Node
  __metaclass__
This Metaclass is meant to overwrite doc strings of methods like execute, stop_training, inverse with the ones defined in the corresponding private methods _execute, _stop_training, _inverse, etc...
Instance Methods [hide private]
 
__init__(self, approach='defl', g='pow3', guess=None, fine_g='pow3', mu=1, stabilization=False, sample_size=1, fine_tanh=1, fine_gaus=1, max_it=1000, max_it_fine=100, failures=5, limit=0.001, verbose=False, whitened=False, white_comp=None, white_parm=None, input_dim=None, dtype=None)
Input arguments:
 
_get_rsamples(self, X)
 
core(self, data)
This is the core routine of the ICANode.

Inherited from unreachable.ProjectMatrixMixin: get_projmatrix, get_recmatrix

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

    Inherited from ICANode
 
_execute(self, x)
 
_get_supported_dtypes(self)
Return the list of dtypes supported by this node.
 
_inverse(self, y)
 
_set_input_dim(self, n)
 
_stop_training(self)
Whiten data if needed and call the 'core' routine to perform ICA.
 
stop_training(self, *args, **kwargs)
Whiten data if needed and call the 'core' routine to perform ICA.
    Inherited from Cumulator
 
_train(self, x)
Cumulate all input data in a one dimensional list.
 
train(self, x, *args, **kwargs)
Cumulate all input data in a one dimensional list.
    Inherited from Node
 
__add__(self, other)
 
__call__(self, x, *args, **kargs)
Calling an instance of Node is equivalent to call 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)
 
_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)
 
_set_output_dim(self, n)
 
copy(self, protocol=-1)
Return a deep copy of the node.
 
execute(self, x, *args, **kargs)
Process the data contained in 'x'.
 
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.
 
inverse(self, y, *args, **kargs)
Invert 'y'.
 
is_invertible(self)
Return True if the node can be inverted, False otherwise.
 
is_trainable(self)
Return True if the node can be trained, False otherwise.
 
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'.
 
set_dtype(self, t)
Set internal structures' dtype.
 
set_input_dim(self, n)
Set input dimensions.
 
set_output_dim(self, n)
Set output dimensions.
Properties [hide private]

Inherited from object: __class__

    Inherited from Node
  _train_seq
List of tuples: [(training-phase1, stop-training-phase1), (training-phase2, stop_training-phase2), ...
  dtype
dtype
  input_dim
Input dimensions
  output_dim
Output dimensions
  supported_dtypes
Supported dtypes
Method Details [hide private]

__init__(self, approach='defl', g='pow3', guess=None, fine_g='pow3', mu=1, stabilization=False, sample_size=1, fine_tanh=1, fine_gaus=1, max_it=1000, max_it_fine=100, failures=5, limit=0.001, verbose=False, whitened=False, white_comp=None, white_parm=None, input_dim=None, dtype=None)
(Constructor)

 

    Input arguments:

    General:

    whitened -- Set whitened == True if input data are already whitened.
                Otherwise the node will whiten the data itself

    white_comp -- If whitened == False, you can set 'white_comp' to the
                  number of whitened components to keep during the
                  calculation (i.e., the input dimensions are reduced to
                  white_comp by keeping the components of largest variance).
    
    white_parm -- a dictionary with additional parameters for whitening.
                  It is passed directly to the WhiteningNode constructor.
                  Ex: white_parm = { 'svd' : True }

    limit -- convergence threshold.
    
    Specific for FastICA:

    approach  -- Approach to use. Possible values are:
                                      'defl' --> deflation
                                      'symm' --> symmetric

           g  -- Nonlinearity to use. Possible values are:
                                      'pow3' --> x^3
                                      'tanh' --> tanh(fine_tanh*x)
                                      'gaus' --> x*exp(-fine_gaus*x^2/2)
                                      'skew' --> x^2 (for skewed signals)

       fine_g -- Nonlinearity for fine tuning. Possible values
                 are the same as for 'g'. Set it to None to disable fine
                 tuning.

           mu -- Step size

stabilization -- Enable stabilization procedure: the value of mu can
                 momentarily be halved if the algorithm is stuck between
                 two points (this is called a stroke). Also if there is no
                 convergence before half of the maximum number of
                 iterations has been reached then mu will be halved for
                 the rest of the rounds.

  sample_size -- Percentage of samples used in one iteration. If
                 sample_size < 1, samples are chosen in random order.
                 
    fine_tanh -- parameter for 'tanh' nonlinearity
    fine_gaus -- parameter for 'gaus' nonlinearity

        guess -- initial guess for the mixing matrix (ignored if None)
        
       max_it -- maximum number of iterations

  max_it_fine -- maximum number of iterations for fine tuning

     failures -- maximum number of failures to allow in deflation mode
     
    

Overrides: object.__init__

_get_rsamples(self, X)

 

core(self, data)

 
This is the core routine of the ICANode. Each subclass must
define this function to return the achieved convergence value.
This function is also responsible for setting the ICA filters
matrix self.filters.
Note that the matrix self.filters is applied to the right of the
matrix containing input data. This is the transposed of the matrix
defining the linear transformation.

Overrides: ICANode.core
(inherited documentation)