On Tue, Dec 16, 2008 at 12:50 AM, achrzesz <achrz...@wp.pl> wrote: > > Hallo, > I'm wondering what goes wrong with tis: > > (sage 3.2 compiled from sources, ubuntu 8.04, quad core 2.4 GHz) > > > sage: for k in range(14,21): > ....: f=2^2^k+1;w=ecm.find_factor(f);[w[0],prod(w)==f] > ....: > [2, False] > [523923, False] > [1901173, False] > [2, False] > [2, False] > [30539, False] > [2, False] > > Are the exponents to big? > > Andrzej Chrzeszczyk
Yes, I think there must be a hard limit on the input line for GMP-ECM. If I try the first number directly on the command line, it says "Factor found in step 1: 2". However the first number is *odd*, so 2 can't be a factor! What's really happening is that GMP-ECM is ignoring everything after the first 4095 digits when I paste the input in. ecm 10000000 100000 GMP-ECM 6.1.3 [powered by GMP 4.2.1] [ECM] 118973149535723176508575932662800713076344468709651023747267482123326135818048368690448859547261203991511543748483930925889766738130868742627452469834156500608087163436600489752214325161953144684595234570948213584703664746483098478471428096784561413847604433840488612290528685531323615869599988579010635701812081536332078096432371275716429061340687520241736532395026788008906751737227061083564754575578079343162221345190381785963069031134385065753936064964519328317829176765896540528511355613436979328172588801590841467528983253806341923488859989898062311402512167447205187243932132319840294270534136695127473901459381689828899444517340036461792837713807441134579184857359507717043764419174388964488537768473832224060823907906139947567533473978401649174262148522901484767233597789715839733422634973481144165307775825098892603089478960467615310425726014180682302758800344195145532770159807128158959716941396560843950498317125506228202662620004804214980820000206099343368123762385788062747972707287748283843870504803416463333701338540599804070190866238730160501818826257372376627924079893171770880790174026540793097641964887786960401751769193868798808800894425125882696968836419413394578015784436494605271365545490632718742853189510027869511932349680870363043619392759269234482081283429736447868686206416904245855513653205505050818989186684686379991764754729137157350070101519755909745304003303152068351821649419563669607774811059828490134361146921427412181049507797927555664516498385006205106651708464736946403664056933946483717218335295687391204264000361161878927819571005209456276130670355184033011064510199543516762668866962776382060434248035790641535421273294675607300690708887049612505006815665925276129766406549834749266179882406231221040927458456558726484641765016012317587403472626195728908146619765155383074442470969863475362777035622712614505254912522944804014911479568135987596851280857524427187145545408489498615502079480698093921565805531916564168110596645415995147690858312972150329881658514207306148088802176981833841712939687837145957584605258314292844724970369854812529577592093645002265142724994958070820396608284755092189115213332104801197388363657782553332598885215632543933502131531213408139045102125536370790349591696312592420116787719010893525591453948821689711794326937360863907447279275111671512710639642508135355313721355289053980260297864531979510097643293909192466022887891290065421011828729829870738215971718456954051540302917330729245439178956867421964076145117360061775218699191336683703388720158207162586824713310451331509727471344272834060664289040649663610444321775281122747002916285809372770104964649954022098398193278661320425422646424368961010742992319763868154583756177353556898453605362723442427710576092486402378162966552631491090696048807347521700512113631187043992576250866603256621375041669571991967422321060672472137347123402161354071218823990970197194394434748031421790388631776777992153989217733434436890755031880083354685234437032708928414750164058944848200125423738668007445734191093377489195968101651606910614990557242581089558693883306749020490036862416630196855300568704028509545048484007352864382657040376715728651238025510995451885701347658818930000413884971588313986607154757481647672763511643546280440111271139252918057079419342268681835321279906897224769719147426815791219597379419280729888695236110088026425880132092804001192815397080113074133955000329901592497825993697435872628614398052011245436927111408374791900780340659632135341700406886944340547214067596364099740500922580350567272646509550626733926889242436456189766190689842418677049103534408039924832709791171288114017038418205860161475828420075018350032935849969186406659053966070906953738160188767904665775965458800193711777134469832642879262289433801611244553353944708746204976340914754209924881552139592938800771117201789489779370660427348098516102881545878791116097911342243355754917090544202639727569528320730533184541999074934781052400619419720059165214786719369625433786498160383314635420170062881794717751811521767435201651117234772772707522005617774821892859715834674454[[I hear bings as all further digits are ignored]] Input number has 4095 digits ********** Factor found in step 1: 2 Found probable prime factor of 1 digits: 2 Composite cofactor 59486574767861588254287966331400356538172234354825511873633741061663067909024184345224429773630601995755771874241965462944883369065434371313726234917078250304043581718300244876107162580976572342297617285474106792351832373241549239235714048392280706923802216920244306145264342765661807934799994289505317850906040768166039048216185637858214530670343760120868266197513394004453375868613530541782377287789039671581110672595190892981534515567192532876968032482259664158914588382948270264255677806718489664086294400795420733764491626903170961744429994949031155701256083723602593621966066159920147135267068347563736950729690844914449722258670018230896418856903720567289592428679753858521882209587194482244268884236916112030411953953069973783766736989200824587131074261450742383616798894857919866711317486740572082653887912549446301544739480233807655212863007090341151379400172097572766385079903564079479858470698280421975249158562753114101331310002402107490410000103049671684061881192894031373986353643874141921935252401708231666850669270299902035095433119365080250909413128686188313962039946585885440395087013270396548820982443893480200875884596934399404400447212562941348484418209706697289007892218247302635682772745316359371426594755013934755966174840435181521809696379634617241040641714868223934343103208452122927756826602752525409494593342343189995882377364568578675035050759877954872652001651576034175910824709781834803887405529914245067180573460713706090524753898963777832258249192503102553325854232368473201832028466973241858609167647843695602132000180580939463909785502604728138065335177592016505532255099771758381334433481388191030217124017895320767710636647337803650345354443524806252503407832962638064883203274917374633089941203115610520463729228279363242320882508006158793701736313097864454073309882577691537221235484931737681388517811356307252627456261472402007455739784067993798425640428762213593572772704244749307751039740349046960782902765958282084055298322707997573845429156486075164940829257103653074044401088490916920856469843918572978792302629157146422362485184927406264788796046822501132571362497479035410198304142377546094557606666052400598694181828891276666299442607816271966751065765606704069522551062768185395174795848156296210058393859505446762795726974410844855897163468680431953723639637555835756355319821254067677656860677644526990130148932265989755048821646954596233011443945645032710505914364914935369107985859228477025770151458665364622719589478433710982038072558680030887609349595668341851694360079103581293412356655225665754863735672136417030332144520324831805222160887640561373501458142904686385052482324977011049199096639330660212711323212184480505371496159881934077291878088676778449226802681361721213855288046243201189081483276315745545348024403673760850256056815593521996288125433301628310687520834785995983711160530336236068673561701080677035609411995485098597197217374015710895194315888388996076994608866717218445377515940041677342617218516354464207375082029472424100062711869334003722867095546688744597984050825803455307495278621290544779346941653374510245018431208315098427650284352014254772524242003676432191328520188357864325619012755497725942850673829409465000206942485794156993303577378740823836381755821773140220055635569626459028539709671134340917660639953448612384859573713407895609798689709640364944347618055044013212940066046402000596407698540056537066977500164950796248912996848717936314307199026005622718463555704187395950390170329816067670850203443472170273607033798182049870250461290175283636323254775313366963444621218228094883095344921209338524551767204019962416354895585644057008519209102930080737914210037509175016467924984593203329526983035453476869080094383952332887982729400096855888567234916321439631144716900805622276676972354373102488170457377104962440776069796469400385558600894744889685330213674049258051440772939395558048955671121677877458545272101319863784764160365266592270999537467390526200309709860029582607393359684812716893249080191657317710085031440897358875905760883717600825558617386386353761002808887410946429857917337227 has 4094 digits However, note that sage: len(str(f)) 4933 Paul -- does GMP-ECM have a by-design hard limit of 4095 digits? If so, then we have to give an error message from Sage immediately (raise a ValueError). If not, how do we get around the command line 4095 digit limit? Note to self -- the function find_factor in Sage absolutely should have had a built-in consistency check that everything found was really a factor. It can't hurt to do that, and may have caught problems like this earlier. This is now http://trac.sagemath.org/sage_trac/ticket/4814 -- William --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
