Difference between revisions of "V"

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m (update)
m (fix)
Line 31: Line 31:
  
 
for (...) {
 
for (...) {
   pos.project_(heading, velocity); // trailing dash means inplace
+
   pos.project_(heading, velocity); // trailing underscore means inplace
 
}
 
}
 
</syntaxhighlight>
 
</syntaxhighlight>
Line 42: Line 42:
  
 
for (...) {
 
for (...) {
   double nextX = ...; // some fast math
+
   double dx = ...; // some fast math
   double nextY = ...; // some fast math
+
   double dy = ...; // some fast math
  
   x = nextX;
+
   x += dx;
   y = nextY;
+
   y += dy;
 
}
 
}
 
</syntaxhighlight>
 
</syntaxhighlight>

Revision as of 07:34, 8 August 2018

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




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;
}