https://github.com/mikolalysenko/polytope-closest-point

Computes the closest point on a convex polytope to a given point.
https://github.com/mikolalysenko/polytope-closest-point

Last synced: about 2 months ago
JSON representation

Computes the closest point on a convex polytope to a given point.

• Host: GitHub
• URL: https://github.com/mikolalysenko/polytope-closest-point
• Owner: mikolalysenko
• License: bsl-1.0
• Created: 2013-02-15T18:35:58.000Z (almost 12 years ago)
• Default Branch: master
• Last Pushed: 2014-11-14T23:21:06.000Z (about 10 years ago)
• Last Synced: 2024-10-20T14:28:19.529Z (2 months ago)
• Language: JavaScript
• Size: 156 KB
• Stars: 9
• Watchers: 3
• Forks: 3
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.txt

Awesome Lists containing this project

README

        
polytope-closest-point

======================

Computes the closest point in a convex polytope to a given point.

Install

=======

Using npm, type the following command into your shell:

    npm install polytope-closest-point

Usage

=====

Here is an example of how to find the closest point to a triangle in a mesh:

    var mesh = require("bunny");

    var result = new Array(3);

    var sqr_distance = require("polytope-closest-point")(

                          mesh.cells[0],

                          mesh.positions,

                          [0,0,0],

                          result);

Which computes the closest point in the first facet of the mesh to the point `[0,0,0]`, storing the resulting point in `result` and the squared distance in `sqr_distance`.

For more examples, see test/simple.js.

### `require("polytope-closest-point")(cell, positions, x[, result])`

Computes the closest point in a polytope to `x`, storing the result in `result`.

* `cell` is a list of indices into a positions representing the vertices of the polytope.

* `positions` is an array of tuples representing the vertices of the polytope

* `x` is the point we are querying against

* `result` (optional) is the array to store the closest point in.

Returns a float representing the squared Euclidean distance from x to the polytope.  If no such point can be found, it returns Number.NaN

Notes:  For polytopes with fewer than 4 vertices, the code uses hand optimized routines derived from WildMagick.  For higher dimensions, it falls back to a general purpose quadratic programming solver that is ported from somewhat slower R/FORTRAN codes.  If you are planning on using this code to do distance queries on meshed surfaces, it is recommend you triangulate all your polygons first.

Credits

=======

Triangle/tetrahedra closest point code derived from WildMagick (c) David Eberly 1998-2012.

Other dimensions, (c) 2013 Mikola Lysenko

BOOST License.