We therefore study another solution to this problem that is inspired by Sequential importance sampling methods (Doucet and Johansen, 2011;Buys and Blunsom, 2015) and that can be interpreted as a variable beam search strategy where the search method carefully avoids to compare apples and oranges within the same beam.
the method ensures that comparisons between derivations are made only if derivations have an identical number of generated lexical elements.