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Improved Read me.

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Andrew Lawson Andrew Lawson
Andrew Lawson authored and Andrew Lawson committed Dec 11, 2014
1 parent f1b2a05 commit ed22d97055915466c48f029a78fb1b1a2cce8015
Showing with 10 additions and 2 deletions.
  1. +10 −2 README.md
@@ -9,20 +9,28 @@ This program is based off the paper [Geometric Separators and the Parabolic Lift
About:
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This Processing program will allow you to input a number of 2D points and will calculate the geometric separator for the input set. It will graphically show the centerpoint and the spherical separator projected down to the 2D plane.
This Processing program will allow you to input a number of 2D points and determine a geometric separator for the input set. It will graphically show the centerpoint and the spherical separator projected down to the 2D plane.

How it works:
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The points input by the user will be lifted to a paraboloid in 3D. Then, we approximate a centerpoint from sets of 5 points by using [Iterated Radon Points](http://dl.acm.org/citation.cfm?id=161004). To find a Radon point from a set of 5 points, there are two cases we must test for: 1) if a ray intersects a triangle and 2) if a point is inside a tetrahedron. The intersection point or contained point, respectively, is then the Radon point. These Radon points are reduced down to a single point - our estimated centerpoint. A sphere is then calculated and projected down to the original 2D plane along with the centerpoint.

Usage:
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There are three buttons on the application window: **Calculate**, **Reset**, and **Randomize**.
You can click anywhere on the canvas to add input points. Then, use the **Calculate** button, which will show the centerpoint (if it can) and the separator projected down to the 2D plane. If you don't have specific points, you can use the **Randomize** button to add 25 random points to the canvas. To remove added points, just click **Reset**.
You can click anywhere on the canvas to add input points. Then, use the **Calculate** button, which will show the centerpoint in *red* (if it can) and the separator projected down to the 2D plane as a *gray* ellipse. If you don't have specific points, you can use the **Randomize** button to add 25 random points to the canvas. To remove added points, just click **Reset**.

Note: The centerpoint is estimated using Radon Points - according to Radon's Theorem, we can only find a partition for sets of 5 points, so we must only have powers of 5 for our input set.

References:
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http://donsheehy.net/research/sheehy13geometric.pdf

http://dl.acm.org/citation.cfm?id=161004

http://steve.hollasch.net/cgindex/geometry/ptintet.html

http://geomalgorithms.com/a06-_intersect-2.html

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