{'fraction_non_alphanumeric': 0.018292682926829267, 'fraction_numerical': 0.0, 'mean_word_length': 5.32051282051282, '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}}
Why “Building Blocks” Don’t Work on Parity Problems

We investigate the distribution of performance of the parity and always-on Boolean functions given only the appropriate building block. These problems have “needle in a haystack” fitness landscape and so are unsuitable for genetic programming or other progressive search techniques. Theoretical analysis shows in the limit as program size grows the density of solutions is independent of size but falls exponentially with number of inputs.