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CLocalTangentSpaceAlignment Class Reference

Detailed Description

LocalTangentSpaceAlignment used to embed data using Local Tangent Space Alignment (LTSA) algorithm as described in:

Zhang, Z., & Zha, H. (2002). Principal Manifolds and Nonlinear Dimension Reduction via Local Tangent Space Alignment. Journal of Shanghai University English Edition, 8(4), 406-424. SIAM. Retrieved from http://arxiv.org/abs/cs/0212008

Due to performance reasons on high-dimensional datasets please use KernelLocalTangentSpaceAlignment with linear kernel.

The stated eigenproblem is solved in the same way as CLocallyLinearEmbedding (LAPACK or ARPACK if available).

The local tangent space alignment step is parallel. Neighborhood determination is parallel as in CLocallyLinearEmbedding.

This algorithm is pretty stable for variations of k parameter value but be sure it is set with a consistent value (at least 3-5) for reasonable results.

Please do not use multithreading whether your LAPACK is not thread-safe.

Definition at line 50 of file LocalTangentSpaceAlignment.h.

Inheritance diagram for CLocalTangentSpaceAlignment:
Inheritance graph
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Public Member Functions

 CLocalTangentSpaceAlignment ()
virtual ~CLocalTangentSpaceAlignment ()
virtual const char * get_name () const
- Public Member Functions inherited from CLocallyLinearEmbedding
 CLocallyLinearEmbedding ()
virtual ~CLocallyLinearEmbedding ()
virtual CFeaturesapply (CFeatures *features)
void set_k (int32_t k)
int32_t get_k () const
void set_max_k (int32_t max_k)
int32_t get_max_k () const
void set_auto_k (bool auto_k)
bool get_auto_k () const
void set_reconstruction_shift (float64_t reconstruction_shift)
float64_t get_reconstruction_shift () const
void set_nullspace_shift (float64_t nullspace_shift)
float64_t get_nullspace_shift () const
void set_use_arpack (bool use_arpack)
bool get_use_arpack () const
- Public Member Functions inherited from CEmbeddingConverter
 CEmbeddingConverter ()
virtual ~CEmbeddingConverter ()
virtual CSimpleFeatures
< float64_t > * 
embed (CFeatures *features)
void set_target_dim (int32_t dim)
int32_t get_target_dim () const
void set_distance (CDistance *distance)
CDistanceget_distance () const
void set_kernel (CKernel *kernel)
CKernelget_kernel () const
- Public Member Functions inherited from CConverter
 CConverter ()
virtual ~CConverter ()
- Public Member Functions inherited from CSGObject
 CSGObject ()
 CSGObject (const CSGObject &orig)
virtual ~CSGObject ()
virtual bool is_generic (EPrimitiveType *generic) const
template<class T >
void set_generic ()
void unset_generic ()
virtual void print_serializable (const char *prefix="")
virtual bool save_serializable (CSerializableFile *file, const char *prefix="")
virtual bool load_serializable (CSerializableFile *file, const char *prefix="")
void set_global_io (SGIO *io)
SGIOget_global_io ()
void set_global_parallel (Parallel *parallel)
Parallelget_global_parallel ()
void set_global_version (Version *version)
Versionget_global_version ()
SGVector< char * > get_modelsel_names ()
char * get_modsel_param_descr (const char *param_name)
index_t get_modsel_param_index (const char *param_name)

Protected Member Functions

virtual SGMatrix< float64_tconstruct_weight_matrix (CSimpleFeatures< float64_t > *simple_features, float64_t *W_matrix, SGMatrix< int32_t > neighborhood_matrix)
 HELPER.
- Protected Member Functions inherited from CLocallyLinearEmbedding
void init ()
 HELPERS.
virtual SGMatrix< float64_tconstruct_embedding (SGMatrix< float64_t > matrix, int dimension)
virtual SGMatrix< int32_t > get_neighborhood_matrix (SGMatrix< float64_t > distance_matrix, int32_t k)
int32_t estimate_k (CSimpleFeatures< float64_t > *simple_features, SGMatrix< int32_t > neighborhood_matrix)
float64_t compute_reconstruction_error (int32_t k, int dim, int N, float64_t *feature_matrix, float64_t *z_matrix, float64_t *covariance_matrix, float64_t *resid_vector, float64_t *id_vector, SGMatrix< int32_t > neighborhood_matrix)

Static Protected Member Functions

static void * run_ltsa_thread (void *p)
 THREAD.
- Static Protected Member Functions inherited from CLocallyLinearEmbedding
static void * run_neighborhood_thread (void *p)
 THREADS.
static void * run_linearreconstruction_thread (void *p)

Additional Inherited Members

- Public Attributes inherited from CSGObject
SGIOio
Parallelparallel
Versionversion
Parameterm_parameters
Parameterm_model_selection_parameters
- Protected Attributes inherited from CLocallyLinearEmbedding
int32_t m_k
 FIELDS.
int32_t m_max_k
float64_t m_reconstruction_shift
float64_t m_nullspace_shift
bool m_use_arpack
bool m_auto_k

Constructor & Destructor Documentation

constructor

Definition at line 67 of file LocalTangentSpaceAlignment.cpp.

destructor

Definition at line 72 of file LocalTangentSpaceAlignment.cpp.

Member Function Documentation

SGMatrix< float64_t > construct_weight_matrix ( CSimpleFeatures< float64_t > *  simple_features,
float64_t W_matrix,
SGMatrix< int32_t >  neighborhood_matrix 
)
protectedvirtual

HELPER.

construct weight matrix

Parameters
simple_featuresfeatures to be used
W_matrixweight matrix
neighborhood_matrixmatrix containing neighbor idxs

Reimplemented from CLocallyLinearEmbedding.

Definition at line 81 of file LocalTangentSpaceAlignment.cpp.

const char * get_name ( ) const
virtual

get name

Reimplemented from CLocallyLinearEmbedding.

Reimplemented in CLinearLocalTangentSpaceAlignment.

Definition at line 76 of file LocalTangentSpaceAlignment.cpp.

void * run_ltsa_thread ( void *  p)
staticprotected

THREAD.

run ltsa thread

Parameters
pthread params

Definition at line 175 of file LocalTangentSpaceAlignment.cpp.


The documentation for this class was generated from the following files:

SHOGUN Machine Learning Toolbox - Documentation