docs: public static Vector3D_F64 constraint(TrifocalTensor tensor,
  										  Vector3D_F64 l1, Vector3D_F64 l2, Vector3D_F64 l3,
  										  @Nullable Vector3D_F64 ret)
  	{
  		if( ret == null )
  			ret = new Vector3D_F64();
  
  		double x = GeometryMath_F64.innerProd(l2, tensor.T1, l3);
  		double y = GeometryMath_F64.innerProd(l2, tensor.T2, l3);
  		double z = GeometryMath_F64.innerProd(l2, tensor.T3, l3);
  
  		GeometryMath_F64.cross(new Vector3D_F64(x, y, z), l1, ret);
  
  		return ret;
  	}