# Tangential complex reference manual¶

class gudhi.TangentialComplex

Bases: object

The class Tangential_complex represents a tangential complex. After the computation of the complex, an optional post-processing called perturbation can be run to attempt to remove inconsistencies.

__init__()

TangentialComplex constructor.

Parameters
• intrisic_dim (integer) – Intrinsic dimension of the manifold.

• points (list of list of double) – A list of points in d-Dimension.

Or

Parameters

off_file (string) – An OFF file style name.

compute_tangential_complex()

This function computes the tangential complex.

Raises

ValueError – In debug mode, if the computed star dimension is too low. Try to set a bigger maximal edge length value with set_max_squared_edge_length() if this happens.

create_simplex_tree()

Exports the complex into a simplex tree.

Returns

A simplex tree created from the complex.

Return type

SimplexTree

fix_inconsistencies_using_perturbation()

Attempts to fix inconsistencies by perturbing the point positions.

Parameters
• max_perturb (double) – Maximum length of the translations used by the perturbation.

• time_limit (double) – Time limit in seconds. If -1, no time limit is set.

get_point()

This function returns the point corresponding to a given vertex.

Parameters

vertex (int.) – The vertex.

Returns

The point.

Return type

list of float

num_inconsistent_simplices()
Returns

The number of inconsistent simplices.

Return type

unsigned

num_inconsistent_stars()
Returns

The number of stars containing at least one inconsistent simplex.

Return type

unsigned

num_simplices()
Returns

Total number of simplices in stars (including duplicates that appear in several stars).

Return type

unsigned

num_vertices()
Returns

The number of vertices.

Return type

unsigned

set_max_squared_edge_length()

Sets the maximal possible squared edge length for the edges in the triangulations.

Parameters

max_squared_edge_length (double) – Maximal possible squared edge length.

If the maximal edge length value is too low compute_tangential_complex() will throw an exception in debug mode.