public static double determinant2by2(Point2D v0,Point2D v1){
  return (v0.getX() * v1.getY() - v1.getX() * v0.getY());
}

public static double determinant2by2 ( Point2D v0 , Point2D v1 ) { return ( v0 . getX ( ) * v1 . getY ( ) - v1 . getX ( ) * v0 . getY ( ) ) ; }
a fast determinant utility to find the determinant of the 2 by 2 matrix made up of the vectors ( stored as 2d points ) v0 and v1 , i . e . : | v0x v1x | | v0y v1y | used so that more complex determinant algorithms in matrix packages are avoided for such a simple operation . . .
