Hi Seshika, Did u mean, this getFrequencies function, should able to accept another argument, that mean if this apply to a time window if window lenght is 1 day, this function will return last 5 hrs frequency of a day. Is your requirement can fulfill with existing window length or time parameters?
ex -: if you need to extract frequency of last 5 hrs , apply this fuction to 5hrs time window Thanks On Fri, Oct 17, 2014 at 5:10 PM, Seshika Fernando <[email protected]> wrote: > When considering the usecases for this, getting the frequency during a > particular time period will be very useful. (eg:- trading frequency of a > different stocks/products during the last 5 hours) > Does your custom transformer support this? Or does it always take all > events for the frequency calculations? > > On Fri, Oct 17, 2014 at 4:32 PM, Rajeevan Vimalanathan <[email protected] > > wrote: > >> We are planning to integrate Frequency algorithm as a part of training >> project[1] with Siddhi CEP. >> >> Basically this is the algorithm calculates the number of occurrences >> (frequency) of a specified attribute for a given input stream in CEP. >> >> We have selected a Siddhi Transformer to implement this functionality by >> using stream-lib[2] as a third party library which is licensed under Apache >> Software Foundation. >> >> Standard Siddhi query for using this algorithm would look like below, >> >> * from >> inputStream#transform.custom:getFrequencies(desiredAttribute)select >> desiredAttribute, >> frequency* >> *insert into frequencyStream;* >> >> Where, >> >> inputStream : Input Stream to CEP >> >> custom : namespace >> >> getFrequencies : function name >> >> desiredAttribute : Attribute name from input stream for which frequencies >> need to be calculated >> frequencyStream : Output Stream from CEP that contains frequency related >> information >> >> The stream-lib library supports only Top-K and cardinality algorithms >> directly where the Top-K algorithm takes ‘K’ value as an argument from user >> and gives distinct K number of elements which have highest frequency values >> with related frequency values. The library provides no functions for >> getting frequencies of all elements. So what we are planning to do is >> giving a maximum integer value(Integer.MAX_VALUE) as an argument to the >> Top-K algorithm. So obviously, we will be able to get frequencies for all >> distinct event attributes provided that distinct event attribute count does >> not exceed Integer.MAX_VALUE value. >> >> There won’t be any memory issues as giving of Integer.MAX_VALUE for Top-K >> algorithm because it is increasing it’s bucket size dynamically as new >> distinct events come. >> >> We have already implemented the above design and basic testings seem to >> be ok. >> >> Kindly comment on the implementation. >> >> [1] - https://redmine.wso2.com/issues/2884 >> >> [2] - https://github.com/addthis/stream-lib >> >> -- >> Best Regards, >> V.Rajeevan >> Software Engineer, >> WSO2 Inc. :http://wso2.com >> >> Mobile : +94 773090875 >> Email : [email protected] >> >> _______________________________________________ >> Architecture mailing list >> [email protected] >> https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture >> >> > > _______________________________________________ > Architecture mailing list > [email protected] > https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture > > -- Manoj Gunawardena Tech Lead WSO2, Inc.: http://wso2.com lean.enterprise.middleware Mobile : +94 77 2291643
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