Public Member Functions | Protected Member Functions | Static Protected Member Functions

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

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

List of all members.

Public Member Functions

 CLocalTangentSpaceAlignment ()
virtual ~CLocalTangentSpaceAlignment ()
virtual const char * get_name () const

Protected Member Functions

virtual SGMatrix< float64_tconstruct_weight_matrix (CSimpleFeatures< float64_t > *simple_features, float64_t *W_matrix, SGMatrix< int32_t > neighborhood_matrix)

Static Protected Member Functions

static void * run_ltsa_thread (void *p)

Constructor & Destructor Documentation


Definition at line 67 of file LocalTangentSpaceAlignment.cpp.

~CLocalTangentSpaceAlignment (  )  [virtual]


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 
) [protected, virtual]


construct weight matrix

simple_features features to be used
W_matrix weight matrix
neighborhood_matrix matrix 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  )  [static, protected]


run ltsa thread

p thread params

Definition at line 175 of file LocalTangentSpaceAlignment.cpp.

The documentation for this class was generated from the following files:
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Defines

SHOGUN Machine Learning Toolbox - Documentation