I'm using the latest Mahout's release available in the Maven repository. Thank you for your suggestion, I'll try it.
Alessandro Suglia Il 06/mag/2014 07:10 Sebastian Schelter <[email protected]> ha scritto: > > Alessandro, > > which version of Mahout are you using? I had a look at the current > impl ementation of GenericBooleanPrefUserBasedRecommender and its > doEstimatePreference method returns the sum of similarities of users > that have also interacted with the item. So that should be different > from either 0 or 1. > > --sebastian > > On 05/03/2014 05:00 PM, Alessandro Suglia wrote: > > Sorry Sebastian, maybe you haven't the possibility to read the post on > > SO, so I'll report the code here. > > I've already used the GenericBooleanPrefUserBasedRecommender in order to > > generate the recommendation and the results are the same. > > > > | DataModel trainModel= new FileDataModel(new > > File(String.valueOf(Main.class.getResource("/binarized/u1.base").getFile()))); > > > > DataModel testModel= new FileDataModel(new > > File(String.valueOf(Main.class.getResource("/binarized/u1.test").getFile()))); > > > > UserSimilarity similarity= new > > TanimotoCoefficientSimilarity(trainModel); > > UserNeighborhood neighborhood= new NearestNUserNeighborhood(35, > > similarity, trainModel); > > > > GenericBooleanPrefUserBasedRecommender userBased= new > > GenericBooleanPrefUserBasedRecommender(trainModel, neighborhood, > > similarity); > > > > long firstUser= testModel.getUserIDs().nextLong(); // get the > > first user > > > > // try to recommender items for the first user > > for(LongPrimitiveIterator iterItem= > > testModel.getItemIDsFromUser(firstUser).iterator(); > > iterItem.hasNext(); ) { > > long currItem= iterItem.nextLong(); > > // estimates preference for the current item for the first user > > System.out.println("Estimated preference for item" + > > currItem+ " is" + userBased.estimatePreference(firstUser, currItem)); > > > > } > > > > | > > > > Can you explain to me where is the error in this code? > > > > Thank you. > > > > On 05/03/14 16:42, Sebastian Schelter wrote: > >> You should try the > >> > >> org.apache.mahout.cf.taste.impl.recommender.GenericBooleanPrefUserBasedRecommender > >> > >> > >> which has been built to handle such data. > >> > >> Best, > >> Sebastian > >> > >> > >> On 05/03/2014 04:34 PM, Alessandro Suglia wrote: > >>> I have described it in the SO's post: > >>> "When I execute this code, the result is a list of 0.0 or 1.0 which are > >>> not useful in the context of top-n recommendation in implicit feedback > >>> context. Simply because I have to obtain, for each item, an estimated > >>> rate which stays in the range [0, 1] in order to rank the list in > >>> decreasing order and construct the top-n recommendation appropriately." > >>> On 05/03/14 16:25, Sebastian Schelter wrote: > >>>> Hi Allessandro, > >>>> > >>>> what result do you expect and what do you get? Can you give a concrete > >>>> example? > >>>> > >>>> --sebastian > >>>> > >>>> On 05/03/2014 12:11 PM, Alessandro Suglia wrote: > >>>>> Good morning, > >>>>> I've tried to create a recommender system using Mahout in an implicit > >>>>> feedback situation. What I'm trying to do is explained exactlly in > >>>>> this > >>>>> post on stack overflow: > >>>>> http://stackoverflow.com/questions/23077735/mahout-recommendation-in-implicit-feedback-situation. > >>>>> > >>>>> > >>>>> > >>>>> > >>>>> > >>>>> > >>>>> As you can see, I'm having some problem with it simply because I > >>>>> cannot > >>>>> get the result that I expect (a value between 0 and 1) when I try to > >>>>> predict a score for a specific item. > >>>>> > >>>>> Someone here can help me, please? > >>>>> > >>>>> Thank you in advance. > >>>>> > >>>>> Alessandro Suglia > >>>>> > >>>> > >>> > >> > > > > >
