public double execute(double in) throws DMLRuntimeException {
    switch (bFunc) {
      case SIN:
        return FASTMATH ? FastMath.sin(in) : Math.sin(in);
      case COS:
        return FASTMATH ? FastMath.cos(in) : Math.cos(in);
      case TAN:
        return FASTMATH ? FastMath.tan(in) : Math.tan(in);
      case ASIN:
        return FASTMATH ? FastMath.asin(in) : Math.asin(in);
      case ACOS:
        return FASTMATH ? FastMath.acos(in) : Math.acos(in);
      case ATAN:
        return Math.atan(in); // faster in Math
      case CEIL:
        return FASTMATH ? FastMath.ceil(in) : Math.ceil(in);
      case FLOOR:
        return FASTMATH ? FastMath.floor(in) : Math.floor(in);
      case LOG:
        return FASTMATH ? FastMath.log(in) : Math.log(in);
      case LOG_NZ:
        return (in == 0) ? 0 : FASTMATH ? FastMath.log(in) : Math.log(in);
      case ABS:
        return Math.abs(in); // no need for FastMath	
      case SIGN:
        return FASTMATH ? FastMath.signum(in) : Math.signum(in);
      case SQRT:
        return Math.sqrt(in); // faster in Math
      case EXP:
        return FASTMATH ? FastMath.exp(in) : Math.exp(in);
      case ROUND:
        return Math.round(in); // no need for FastMath

      case PLOGP:
        if (in == 0.0) return 0.0;
        else if (in < 0) return Double.NaN;
        else return (in * (FASTMATH ? FastMath.log(in) : Math.log(in)));

      case SPROP:
        // sample proportion: P*(1-P)
        return in * (1 - in);

      case SIGMOID:
        // sigmoid: 1/(1+exp(-x))
        return FASTMATH ? 1 / (1 + FastMath.exp(-in)) : 1 / (1 + Math.exp(-in));

      case SELP:
        // select positive: x*(x>0)
        return (in > 0) ? in : 0;

      default:
        throw new DMLRuntimeException("Builtin.execute(): Unknown operation: " + bFunc);
    }
  }
  /**
   * Get the useful angles for eclipse computation.
   *
   * @param position the satellite's position in the selected frame.
   * @param frame in which is defined the position
   * @param date the date
   * @return the 3 angles {(satCentral, satSun), Central body apparent radius, Sun apparent radius}
   * @exception OrekitException if the trajectory is inside the Earth
   */
  private double[] getEclipseAngles(
      final Vector3D position, final Frame frame, final AbsoluteDate date) throws OrekitException {
    final double[] angle = new double[3];

    final Vector3D satSunVector =
        sun.getPVCoordinates(date, frame).getPosition().subtract(position);

    // Sat-Sun / Sat-CentralBody angle
    angle[0] = Vector3D.angle(satSunVector, position.negate());

    // Central body apparent radius
    final double r = position.getNorm();
    if (r <= equatorialRadius) {
      throw new OrekitException(OrekitMessages.TRAJECTORY_INSIDE_BRILLOUIN_SPHERE, r);
    }
    angle[1] = FastMath.asin(equatorialRadius / r);

    // Sun apparent radius
    angle[2] = FastMath.asin(Constants.SUN_RADIUS / satSunVector.getNorm());

    return angle;
  }