{'fraction_non_alphanumeric': 0.01627906976744186, 'fraction_numerical': 0.0, 'mean_word_length': 5.246376811594203, '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}}
Computation of the discrete autocovariance

Given an Nth-order discrete system, the autocovariance sequence is formulated as a set of recursive and non-recursive difference equations. Application of the final value theorem for a z transform then permits the first N terms of the steady-state autocovariance sequence to be computed via one matrix inversion. The remaining terms are calculated using a simple recursive relationship.