Perf: extend Coordinate with distanceSq and distance3DSq

[jandam]

This is simple optimization to avoid computing Math.sqrt during finding minimal distance.
Suggested method can be used for example in LineSegment, Triangle, InteriorPointPoint, InterirorPointLine, , LineString::equalsExact(Geometry other, double tolerance)

 public double distanceSq(Coordinate c) {
    double dx = x - c.x;
    double dy = y - c.y;
    return dx * dx + dy * dy;
  }

  public double distance3DSq(Coordinate c) {
    double dx = x - c.x;
    double dy = y - c.y;
    double dz = z - c.z;
    return dx * dx + dy * dy + dz * dz;
  }

[dr-jts]

Interesting. Is the use of Math.sqrt() a significant performance hit?

[jandam]

I didn't make any benchmarks. It's just very simple micro optimization used in games. Computing min distance is O(n). And we can compute Math.sqrt only once.

[dr-jts]

I think I'd prefer to name these distanceSqr and distanceSqr3D

[jandam]

Yes it's better. English is not my native language. So method names are up tu you.

[jnh5y]

I'd agree that comparing and minimizing the square of the distances is a typical trick to save some cycles. I'm +1 on it.

[FObermaier]

DistanceSquared.pointToPoint(Coordinate, Coordinate) is part of #427.
But not as a member of Coordinate