Converting GUDHI Persistence Diagrams to Giotto

[mukhituly]

Hi everyone!

Is it possible to convert GUDHI Persistence Diagrams into Giotto Format?

[wreise]

Hi @mukhituly !
Yes, it is. A persistence diagram in gudhi is a list, where each element is of the form (dimension, pair(birth, death)). In giotto-tda, the elements of that list are [birth, death, dimension]. Hence, for example,
np.array([[b, d, dim] for dim, (b,d) in gudhi_diagram]) should give you a diagram in the giotto-format.

Since giotto relies on GUDHI for some computations, this conversion is done in gtda/homology/_utils.py::_postprocess_diagrams.py.

Note that extended persistence diagrams in gudhi are slightly different: the list of points is partitioned into 4 parts (possible empty) and each of them has a different interpretation. Currently, it is possible to treat only those from the first part (ordinary persistence) using giotto.

Please let me know if that helps.