On Sat, Jan 31, 2009 at 3:39 PM, Tony Cappellini <cappy2...@gmail.com> wrote: > > > Has anyone ever measured how random (or deterministic) a given sequence of > numbers generated by rand.randint() are? > > Using these arguments for rand.randint(0, 10000000 ) > if a program which calls rand.randint() runs for 10 hours (or a few days), > will it keep generating a repeatable set of numbers at some point? I'm > trying to understand the periodicity (or lack of) of the numbers generated > by rand.randint()
According to the docs http://docs.python.org/library/random.html "Python uses the Mersenne Twister as the core generator. It produces 53-bit precision floats and has a period of 2**19937-1." http://en.wikipedia.org/wiki/Mersenne_twister 2**29937-1 is about 10**13819 which is a pretty big number :-) You would have to use over 10**13808 numbers per second to start repeating in 10 hours. So I think you are safe. Kent PS The exact value of 2**19937-1 is 431542479738816264805523551633791983905393504322671150516525054140333068013765809113045136293185846655452699382576488353179022173345844139095282691546091680190078753437413962968019201144864809026614143184432769803000667281049840954515881760771329698437621346217903963913412852056276196005131066463766486159942366754865374802419643502959351686623639090479483476923139783013778207857124190544743328445291831729732423108882650813216264694510777078122828294447750226804880578200287646593991647662652009005614958003440543536903898628940617928720111208336148084474829135473283672778795656483078469091169458662301697024012602401870287466500334457745703154312929960251877807901193759028631710841496424733789862675033089613749057663409052895722900160380005716308751913739795550474681543332534749910462481325045163417965514705754814592008594726148362138755571168644457897508862779964873043084504842234206292665185560243393391908443689210184248446770427276646018529149252772809226975384267702573339289 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6734625618430175454903864111585429504569920905636741539030968041471 _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
