Complex sentence: The Inside-Outside algorithm is an analogue of the Forward-Backward algorithm, and can be used to compute the total probability of all derivations that are consistent with a given sequence, based on some SCFG.
Split into simpler sentences: The Inside-Outside algorithm is an analogue of the Forward-Backward algorithm. It computes the total probability of all derivations that are consistent with a given sequence, based on some SCFG.