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http://issues.apache.org/bugzilla/show_bug.cgi?id=36215 ------- Additional Comments From [EMAIL PROTECTED] 2005-08-26 17:39 ------- OKay, for the love of Java, let's see the details of all the bugs. I tend to believe they're not all caught yet, but if I have the jar I can definitely test them out. for the current build 8-25-05, the code below HypergeometricDistributionImpl hDist = new HypergeometricDistributionImpl(26932, 270, 823); double probability = hDist.probability(52); double utprobability = hDist.upperCumulativeProbability(52); double cprobability = hDist.cumulativeProbability(52); System.out.println(probability); System.out.println(utprobability); System.out.println(cprobability); System.out.println(1 - cprobability); will return: 1.018427824183987E-26 -2.437485768780334E-10 1.0000000002437486 -2.437485768780334E-10 this shows that in this example, the upper tail cumPro is just 1 - cumPro, which is wrong because of the numeric error accumulation we discusse earlier. but this is obviously not always happening, as when I tried 6000 200 100 50, it returned 6.02E-49, as I expected. what's the mystery here? furthermore, if you run the above code but change it so that it runs HypergeometricDistributionImpl hDist = new HypergeometricDistributionImpl(26932, 823, 270); the result will be different: 1.0184278236099406E-26 3.7159353372118176E-10 0.99999999962840647 3.7159353372118176E-10 but by textbook definition of hypergeometric distribution, the order of numSuccess and sample shouldn't matter at all, notice here: A. the raw probability is slightly different, at the 9th digit; B. this should have generated what the earlier calculation had, but it's totally different. so, summarizing the bugs here: 1. upper tail cumulative probability when running some examples, will overflow and give negative values; 2. upper tail cumPro obviously is not consistently calculating in the same fashion, sometimes it works, sometimes not; 3. the order of numSuccess and sample sometimes matters to the code, while it should not, ever; 4. the raw probability, when change the order of numSuccess and sample, will differ slightly, if it's calculated in exactly the same way then it shouldn't. I suggest that when you have a fix, test it out further with many more examples, like what we suggested here, and in reversing order, etc. and if you could send me the jar or post it here I can test it out as well, rather than waiting for the nightly build to include it. pop numSuccess sample query upperCumPro 26932 823 270 53 1.4160591836816684E-27 26932 270 823 53 6000 200 100 50 6.020909331626761E-49 6000 100 200 50 26896 895 55 15 2.077516591801479E-10 26896 55 895 15 -- Configure bugmail: http://issues.apache.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug, or are watching the assignee. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
