{'fraction_non_alphanumeric': 0.020937188434695914, 'fraction_numerical': 0.003988035892323031, 'mean_word_length': 5.435897435897436, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
A study on unroutable placement recognition

To avoid producing unroutable placement solutions, many state-of-the-art routability-driven placers iteratively invoke global routers to evaluate their placement solutions and then perform routability optimization. However, using a global router to evaluate hard-to-route placement solutions may spend considerable runtime and it cannot guarantee that a placement is truly unroutable to any router. This paper presents an unroutable placement recognizer based on a window-based layout scanning algorithm, which can confirm some placements that are exactly unroutable among a set of hard-to-route placements. In addition, if a placement is recognized to be unroutable, the recognizer can point out unroutable regions and report a lower bound of total overflow for the placement. The experimental results reveal that the proposed recognizer can find out 16 placements that are definitely unroutable among 23 widely used hard-to-route global routing benchmarks.