V

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This page is dedicated for describing the aaa.util.math.V

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V is a vector 2d library that simplifies/boosts geom in robocoding.

It's common for robocoders to write code like this:

Point2D.Double project(Point2D.Double point, double angle, double distance) {
  return new Point2D.Double(point.getX() + distance * Math.sin(angle), point.getY() + distance * Math.cos(angle));
}

Point2D.Double pos = ...;

for (...) {
  pos = project(pos, heading, velocity);
}

However, this is slow.

With V, you have code like this

final V pos = new V(...);

for (...) {
  pos.project_(heading, velocity); // trailing underscore means inplace
}

which is much faster beacuse it can be replaced with scalar internally (in JVM), which means your code actually have the performance of this:

double x = ...;
double y = ...; // 

for (...) {
  double dx = ...; // some fast math
  double dy = ...; // some fast math

  x += dx;
  y += dy;
}

further, V eliminates unnecessary trig in cases like this:

Point2D.Double force = ...;

double angle = absoluteBearing(force); // uses Math.atan2, slow
Point2D.Double dest = project(pos, angle, 100); // uses Math.sin and Math.cos, very slow

With V, you can write:

final V force = ...;

final V dest = pos.project(force, 100); // uses no trig, much faster