Calculating the intersection area of 3 or more circles

Re:Calculating the intersection area of 3 or more circles by shuzchen on Tuesday June 30, 2015 @08:43PM (#9809301)

I notice that when you're trying to calculate whether a point (p) is in a circle (c) you use euclidean distance:

  Math.sqrt((p.x - c.x) ^ 2 + (p.y - c.y) ^ 2) > c.radius

If you're doing this test many, many times (especially as in a Monte Carlo simulation), it'd be more efficient to use distanceSquared:

  (p.x - c.x) ^ 2 + (p.y - c.y) ^ 2 > c.radius ^ 2

Not having to calculate square roots will cut the compute time drastically.

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Re:Calculating the intersection area of 3 or more circles by benfrederickson on Tuesday June 30, 2015 @09:03PM (#9809405)

good point! I actually used this technique recently, to speed up a numerical optimization for laying out venn diagrams: http://www.benfrederickson.com/better-venn-diagrams/

I didn't think of it when I was writing this post though =(

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