import ReferenceFrame;

public class SpacetimePoint extends Object
 {
  public double x,t;

  public SpacetimePoint()
   {
    x = 0;
    t = 0;
   }

  public SpacetimePoint(double abs_x, double abs_t)
   {
    this.x = abs_x;
    this.t = abs_t;
   }

  public SpacetimePoint(ReferenceFrame f, double x, double t)
   {
    this.x = f.abs_x(x,t);
    this.t = f.abs_t(x,t);
   }
 }