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diff --git a/src/Nerve_GIC/utilities/covercomplex.md b/src/Nerve_GIC/utilities/covercomplex.md new file mode 100644 index 00000000..692e44e7 --- /dev/null +++ b/src/Nerve_GIC/utilities/covercomplex.md @@ -0,0 +1,73 @@ +--- +layout: page +title: "Cover complex" +meta_title: "covercomplex" +subheadline: "" +teaser: "" +permalink: "/covercomplex/" +--- +{::comment} +These flags above are here for web site generation, please let them. +cf. https://gitlab.inria.fr/GUDHI/website +Must be in conformity with _data/navigation.yml +{:/comment} + + + +## Nerve ## +This program builds the Nerve of a point cloud sampled on an OFF file. +The cover C comes from the preimages of intervals covering a coordinate function, +which are then refined into their connected components using the triangulation of the .OFF file. + +The program also writes a file SC.txt. +The first three lines in this file are the location of the input point cloud and the function used to compute the cover. +The fourth line contains the number of vertices nv and edges ne of the Nerve. The next nv lines represent the vertices. +Each line contains the vertex ID, the number of data points it contains, and their average color function value. +Finally, the next ne lines represent the edges, characterized by the ID of their vertices. + +**Usage** + +`Nerve <OFF input file> coordinate resolution gain [--v]` + +where + +* `coordinate` is the coordinate function to cover +* `resolution` is the number of the intervals +* `gain` is the gain for each interval +* `--v` is optional, it activates verbose mode. + +**Example** + +`Nerve ../../data/points/human.off 2 10 0.3` + +* Builds the Nerve of a point cloud sampled on a 3D human shape (human.off). +The cover C comes from the preimages of intervals (10 intervals with gain 0.3) covering the height function (coordinate 2). + +`python KeplerMapperVisuFromTxtFile.py -f ../../data/points/human.off_sc.txt` + +* Constructs `human.off_sc.html` file. You can now use your favorite web browser to visualize it. + +## VoronoiGIC ## + +This util builds the Graph Induced Complex (GIC) of a point cloud. +It subsamples *N* points in the point cloud, which act as seeds of a geodesic Voronoï diagram. +Each cell of the diagram is then an element of C. + +The program also writes a file `*_sc.off`, that is an OFF file that can be visualized with GeomView. + +**Usage** + +`VoroniGIC <OFF input file> samples_number [--v]` + +where + +* `samples_number` is the number of samples to take from the point cloud +* `--v` is optional, it activates verbose mode. + +**Example** + +`VoroniGIC ../../data/points/human.off 700` + +* Builds the Voronoi Graph Induced Complex with 700 subsamples from `human.off` file. +`../../data/points/human_sc.off` can be visualized with GeomView. + |