great. thanks a lot.
srowen wrote: > > Yes. Look at PearsonCorrelationSimilarity. It implements > ItemSimilarity so it can compute a Pearson correlation between ratings > for two items. Pearson is the covariance divided by the product of the > standard deviations. So, just multiply the similarity value you get by > the standard deviations of the items' preference values. > > The variance of each item's preference values is simply the square of > the standard deviation, if that's what you mean. > > You can use RunningAverageAndStdDev to help compute standard deviation > if you like. > > On Thu, Nov 26, 2009 at 3:14 PM, jamborta <[email protected]> wrote: >> >> hi guys, >> just wondering if you have a method implemeted which would calculate the >> covariance between two items. and the variance of an item. I looked >> itemSimilarities but that one does something different. >> >> thanks >> Tama >> -- >> View this message in context: >> http://old.nabble.com/Mahout-Taste-covariance-between-two-items-tp26530825p26530825.html >> Sent from the Mahout User List mailing list archive at Nabble.com. >> >> > > -- View this message in context: http://old.nabble.com/Mahout-Taste-covariance-between-two-items-tp26530825p26533265.html Sent from the Mahout User List mailing list archive at Nabble.com.
