This is something fixed in trunk, but you can ignore it. It means your eval is on too little data and the result is not meaningful. On Oct 4, 2012 4:50 PM, "yamo93" <[email protected]> wrote:
> Hi, > > I try to evaluate a boolean data model with RecommenderIRStatsEvaluator > (mahout 0.7). > > I always get this exception : > Exception in thread "main" java.lang.**IllegalArgumentException: Illegal > nDCG: NaN > at com.google.common.base.**Preconditions.checkArgument(** > Preconditions.java:92) > at org.apache.mahout.cf.taste.**impl.eval.IRStatisticsImpl.<** > init>(IRStatisticsImpl.java:**38) > at org.apache.mahout.cf.taste.**impl.eval.** > GenericRecommenderIRStatsEvalu**ator.evaluate(** > GenericRecommenderIRStatsEvalu**ator.java:212) > at net.bluekiwi.bluekarma.**recommender.Evaluate.main(** > Evaluate.java:36) > > I saw that an issue > (https://issues.apache.org/**jira/browse/MAHOUT-1015<https://issues.apache.org/jira/browse/MAHOUT-1015>) > was fixed in this area, is it a collateral issue ? > > Rgds, > Yann. >
