sci-biology ARIADNE is a package of two programs, ariadne and prospero, that compare protein sequences and profiles using the Smith-Waterman algorithm, and assesses statistical significance using a new accurate formula, described in Mott, 2000, "Accurate Formula for P-values of gapped local sequence and profile alignments" J. Mol Biol. 300:649-659. The sequence/profile comparison algorithms used in ARIADNE are standard, and are probably not the fastest implementations available. The novel part is the method for determining statistical significance, which will give thresholds of significance that are accurate to within 5% 95% of the time.