nx_piotroski_lib.nx

nx_piotroski_lib.nx -- F-SCORE: Piotroski 9-point fundamental-strength score, integer-exact. Pairs with the Altman-Z distress engine (nx_fin_zscore): Altman asks "is this firm in trouble?", the Piotroski F-score asks "is this firm's fundamental picture STRENGTHENING?" -- nine binary year-over-year tests across profitability, leverage/liquidity, and operating efficiency, each worth one point, summed 0..9. High (8-9) = strong improving fundamentals; low (0-2) = deteriorating. Every test is an integer comparison -- no float, so the score is reproducible to the point. Inputs are scaled integers (ratios in basis points, money in minor units); a real pipeline gets them from nx_xbrl-parsed filings. ★FAIL-CLOSED + COMPOSES nx_xbrl: the missing-input sentinel PIO_NA is the SAME value nx_xbrl returns for an absent fact (XB_NO_FACT = -999999999). So if any required metric could not be parsed from the filing, pio_fscore returns PIO_INCOMPLETE rather than scoring an unverifiable firm -- a partial F-score read as a real one is exactly the kind of false signal that gets money committed on bad data. DRY: composes nx_matter_lib helpers. license_tier: ORIGINAL No hw writes (Rule 26). LIB.