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Beam search does not guarantee the best sequence
Question: Describe the main limitation of using beam search to find an output Y that maximizes Score_B(Y).
Sample answer: Beam search is a heuristic search method that keeps only the top K partial candidates at each step. Because it prunes away many possibilities, it can discard the sequence that would have ended up with the highest score. As a result, it is not guaranteed to return the true best-scoring output.
Key points:
- Beam search is approximate, not exact.
- It keeps only the top K candidates during the search.
- It may miss the output with the highest score.
Rubric: The answer should explain that beam search is approximate, that it retains only the top K candidates, and that this means it is not guaranteed to find the highest-scoring output.
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Beam search does not guarantee the best sequence