Hi, Anderson, The basic supported aggregation functions are: count, sum, max and min.
However, you can place them inside pretty much any arithmetic operations supported in math.h, therefore, you have quite a bit of freedom in what you can do. For example, the function avg(a) is internally converted to be sum(a) / count(*) The reason to do this is that sum(a) and count(*) can be computed by parts. Functions such as variance and standard deviation are transformed similarly to arithmetic expression of sums and counts. There are two aggregations that are current supported that can not be computed by parts, countdistinct and median. They were supported for a while now. The key challenge of using them is that they require a lot of memory -- all data records needed must be in memory in the current version. Hope this helps. John On 12/9/11 5:07 PM, Anderson C. Carniel wrote: > Hi John! > > I was wondering what aggregation functions FastBit currently supports. > On the site of the documentation is only avg, sum, max and min. > But in the last email you talk about stddev and var. > > I would then know where I can find the complete list of operators > supported by FastBit. > > I will also test the new version of FastBit. > > Thanks, > > Best Regards, > Anderson > > > _______________________________________________ > FastBit-users mailing list > [email protected] > https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users _______________________________________________ FastBit-users mailing list [email protected] https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users
