▁is ▁obtained ▁by ▁partition ing ▁the ▁neighbor ▁function ▁by ▁high - order ▁context s , ▁and ▁compress ing ▁each ▁partition ▁with ▁a ▁wave let ▁tree . ▁ ▁The ▁space ▁usage ▁is ▁extremely ▁compet itive ▁in ▁practice ▁with ▁other ▁state - of - the - art ▁compress ors , ▁and ▁it ▁also ▁supports ▁fast ▁pattern ▁matching . ▁ ▁The ▁memory ▁access es ▁made ▁by ▁com pressed ▁suffix ▁arrays ▁and ▁other ▁com pressed ▁data ▁structures ▁for ▁pattern ▁matching ▁are ▁typically ▁not ▁local ized , ▁and ▁thus ▁these ▁data ▁structures ▁have ▁been ▁not or iously ▁hard ▁to ▁design ▁efficiently ▁for ▁use ▁in ▁external ▁memory . ▁ ▁Rec ent ▁progress ▁using ▁geometric ▁du ality ▁takes ▁advantage ▁of ▁the ▁block ▁access ▁provided ▁by ▁dis ks ▁to ▁speed ▁up ▁the ▁I / O ▁time ▁significantly ▁In ▁addition , ▁potentially ▁practical ▁search ▁performance ▁for ▁a ▁com pressed ▁suffix ▁array ▁in ▁external - memory ▁has ▁been ▁demonstrated . ▁ ▁Open ▁Source ▁Im plement ations ▁There ▁are ▁several ▁open ▁source ▁implementations ▁of ▁com pressed ▁suffix ▁arrays ▁available ▁( see ▁External ▁Link s ▁below ). ▁Bow t ie ▁and ▁Bow t ie 2 ▁are ▁open - source ▁com pressed ▁suffix ▁array ▁implementations ▁of ▁read ▁alignment ▁for ▁use ▁in ▁bio in format ics . ▁The ▁Su cc inct ▁Data ▁Str ucture ▁Library ▁( SD SL ) ▁is ▁a ▁library ▁containing ▁a ▁variety ▁of ▁com pressed ▁data ▁structures ▁including ▁com pressed ▁suffix ▁arrays . ▁F EM TO ▁is ▁an ▁implementation ▁of ▁com pressed ▁suffix ▁arrays ▁for ▁external ▁memory . ▁In ▁addition , ▁a ▁variety ▁of