Dido and Aeneas in three sections, and then disperse. "The palace" Dido and Belinda enter, shocked at Aeneas’ disappearance. Dido is distraught and Belinda comforts her. Suddenly Aeneas returns, but Dido is full of fear before Aeneas speaks, and his words only serve to confirm her suspicions. She derides his reasons for leaving, and even when Aeneas says he will defy the gods and not leave Carthage, Dido rejects him for having once thought of leaving her. After Dido forces Aeneas to leave, she states that "Death must come when he is gone." The opera and Dido's life both slowly come to a
DIDO (software) in solving for the costates in optimal control problems. DIDO generates spectrally accurate solutions whose extremality can be verified using Pontryagin's Minimum Principle. Because no knowledge of pseudospectral methods is necessary to use it, DIDO is often used as a fundamental mathematical tool for solving optimal control problems. That is, a solution obtained from DIDO is treated as a candidate solution for the application of Pontryagin's minimum principle as a necessary condition for optimality. DIDO is used world wide in academia, industry and government laboratories. Thanks to NASA, DIDO was flight-proven in 2006. On November 5, 2006, NASA used DIDO