PLearn::NllSemisphericalGaussianVariable Class Reference

This class implements the negative log-likelihood cost of a Markov chain that uses semispherical gaussian transition probabilities. More...

#include <NllSemisphericalGaussianVariable.h>

Inheritance diagram for PLearn::NllSemisphericalGaussianVariable:

[legend]Collaboration diagram for PLearn::NllSemisphericalGaussianVariable:

[legend]List of all members.


Public Member Functions
	NllSemisphericalGaussianVariable ()
	Default constructor for persistence.
	NllSemisphericalGaussianVariable (const VarArray &the_varray, bool that_use_noise, real theepsilon)
	PLEARN_DECLARE_OBJECT (NllSemisphericalGaussianVariable)
virtual void	build ()
	Should call simply inherited::build(), then this class's build_().
virtual void	recomputeSize (int &l, int &w) const
	Recomputes the length l and width w that this variable should have, according to its parent variables.
virtual void	fprop ()
	compute output given input
virtual void	bprop ()
virtual void	symbolicBprop ()
	compute a piece of new Var graph that represents the symbolic derivative of this Var
Public Attributes
int	n
bool	use_subspace_distance
bool	use_noise
real	epsilon
int	n_dim
int	n_neighbors
Vec	mu
Vec	sm
Vec	sn
Vec	S
Vec	noise
Vec	mu_noisy
Mat	F
Mat	diff_y_x
Mat	z
Mat	B
Mat	Ut
Mat	V
Mat	zn
Mat	zm
Mat	z_noisy
Mat	zn_noisy
Mat	zm_noisy
Vec	p_neighbors
Vec	p_target
Mat	w
Protected Member Functions
void	build_ ()
Private Types
typedef NaryVariable	inherited

Detailed Description

This class implements the negative log-likelihood cost of a Markov chain that uses semispherical gaussian transition probabilities.

The parameters of the semispherical gaussians are a tangent plane, two variances, one mean and the distance of the point with its nearest neighbors. The two variances correspond to the shared variance of every manifold directions and of every noise directions. This variable is used to do gradient descent on the parameters, but not to estimate de likelihood of the Markov chain a some point, which is more complex to estimate.

Definition at line 56 of file NllSemisphericalGaussianVariable.h.

Member Typedef Documentation

typedef NaryVariable PLearn::NllSemisphericalGaussianVariable::inherited [private]

Reimplemented from PLearn::NaryVariable.
Definition at line 58 of file NllSemisphericalGaussianVariable.h.
Referenced by NllSemisphericalGaussianVariable().

Constructor & Destructor Documentation

PLearn::NllSemisphericalGaussianVariable::NllSemisphericalGaussianVariable ( ) [inline]

Default constructor for persistence.

Definition at line 73 of file NllSemisphericalGaussianVariable.h.

PLearn::NllSemisphericalGaussianVariable::NllSemisphericalGaussianVariable ( const VarArray & the_varray,

bool that_use_noise,

real theepsilon

)

Definition at line 66 of file NllSemisphericalGaussianVariable.cc.
References build_(), and inherited.

Member Function Documentation

void PLearn::NllSemisphericalGaussianVariable::bprop ( ) [virtual]

Implements PLearn::Variable.
Definition at line 233 of file NllSemisphericalGaussianVariable.cc.
References PLearn::exp(), F, PLearn::TVec< T >::length(), PLearn::TMat< T >::length(), mu, mu_noisy, n, n_dim, n_neighbors, p_neighbors, p_target, PLearn::pownorm(), sm, sn, use_noise, w, PLearn::TMat< T >::width(), zm, zm_noisy, zn, and zn_noisy.

void PLearn::NllSemisphericalGaussianVariable::build ( ) [virtual]

Should call simply inherited::build(), then this class's build_().
This method should be callable again at later times, after modifying some option fields to change the "architecture" of the object.
Reimplemented from PLearn::Variable.
Definition at line 75 of file NllSemisphericalGaussianVariable.cc.
References build_().

void PLearn::NllSemisphericalGaussianVariable::build_ ( ) [protected]

This method should be redefined in subclasses and do the actual building of the object according to previously set option fields. Constructors can just set option fields, and then call build_. This method is NOT virtual, and will typically be called only from three places: a constructor, the public virtual build() method, and possibly the public virtual read method (which calls its parent's read). build_() can assume that it's parent's build_ has already been called.
Reimplemented from PLearn::Variable.
Definition at line 82 of file NllSemisphericalGaussianVariable.cc.
References B, diff_y_x, F, PLearn::Variable::length(), PLearn::TVec< Var >::length(), mu, mu_noisy, n, n_dim, n_neighbors, noise, p_neighbors, p_target, PLERROR, PLearn::TMat< T >::resize(), sm, sn, Ut, V, w, PLearn::Variable::width(), z, z_noisy, zm, zm_noisy, zn, and zn_noisy.
Referenced by build(), and NllSemisphericalGaussianVariable().

void PLearn::NllSemisphericalGaussianVariable::fprop ( ) [virtual]

compute output given input

Implements PLearn::Variable.
Definition at line 151 of file NllSemisphericalGaussianVariable.cc.
References B, PLearn::TMat< T >::clear(), diff_y_x, epsilon, F, F, k, PLearn::lapackSVD(), PLearn::TVec< T >::length(), PLearn::TMat< T >::length(), PLearn::log(), Log2Pi, mu, mu_noisy, n, n_dim, n_neighbors, noise, PLearn::pownorm(), PLearn::product(), PLearn::TMat< T >::resize(), S, sm, sn, PLearn::substract(), PLearn::transposeProduct(), Ut, V, w, PLearn::TMat< T >::width(), z, z_noisy, zm, zm_noisy, zn, and zn_noisy.

PLearn::NllSemisphericalGaussianVariable::PLEARN_DECLARE_OBJECT ( NllSemisphericalGaussianVariable )

void PLearn::NllSemisphericalGaussianVariable::recomputeSize ( int & l,

int & w

) const [virtual]

Recomputes the length l and width w that this variable should have, according to its parent variables.
This is used for ex. by sizeprop() The default version stupidly returns the current dimensions, so make sure to overload it in subclasses if this is not appropriate.
Reimplemented from PLearn::Variable.
Definition at line 145 of file NllSemisphericalGaussianVariable.cc.
References PLearn::TVec< Var >::length().

void PLearn::NllSemisphericalGaussianVariable::symbolicBprop ( ) [virtual]

compute a piece of new Var graph that represents the symbolic derivative of this Var

Reimplemented from PLearn::Variable.
Definition at line 271 of file NllSemisphericalGaussianVariable.cc.
References PLERROR.