skylab gupta skylabguptagmailcom hello working various probability distributions r seems gamma distribution inaccurate inputs example qgamma1e100 5e101 lowertailfalse gives 10 however seems incorrect think correct answer 0082372029620717283 check numbers using pgamma get pgamma15e101 lowertailfalse 91969860292859463e102 pgamma00823720296207172835e101 lowertailfalse 10000000000000166e100 similarly example qgamma1e1000005lowertailfalse 10936757177007101 pgamma10936757177007101 0005 lowertailfalse 14787306506694758e52 looks completely wrong correct value think 21959373661415756 fact pgamma21959373661415756 0005 lowertailfalse 99999999999999558e101 fact following r results completely wrong xc5e15e25e35e45e55e65e75e85e95e10 z1 qgamma1e100xlowertailfalse ypgammaz1xlowertailfalse value get close 1e100 1 1000000e100 1871683e51 1478731e52 1444034e53 1440606e54 6 1440264e55 1440230e56 1440226e57 1440226e58 1440226e59 correct values z1 z1true c22697154111939946 22215218724493326 21959373661415756 21727485383840451 21498015408183574 21268797118872064 21039614286838227 20810445550564617 20581289009100664 20352144711679352 values z1true get expected values ypgammaz1truexlowertailfalse 1 1e100 1e100 1e100 1e100 1e100 1e100 1e100 1e100 1e100 1e100 using precompiled binary version r windows vista version _ platform i386pcmingw32 arch i386 os mingw32 system i386 mingw32 status major 2 minor 71 year 2008 month 06 day 23 svn rev 45970 language r versionstring r version 271 20080623 seems qgamma inaccurate small probability values upper tail shape parameter also small true fixed missing something thanks alternative html version deleted ______________________________________________ rhelprprojectorg mailing list httpsstatethzchmailmanlistinforhelp please read posting guide httpwwwrprojectorgpostingguidehtml provide commented minimal selfcontained reproducible code tue 05 aug 2008 140401 0700 r qgamma inaccuracy