Can you file a JIRA at https://issues.apache.org/jira/browse/MAHOUT ?
It sounds like you have a test case in mind along with your fix. If you could package that work up as a patch file, then it would be much appreciated. On Sat, Dec 14, 2013 at 9:24 AM, sam wu <swu5...@gmail.com> wrote: > Hi, > > I am using random forest of Mahout. It works well when I don't use feature > descriptor with Ignore feature ( No I flag). > > If using Ignore flag, the returned feature value is -1 > (for in the code dataset.valueOf(aId, token) return -1). > > I did some investigation, and found that there some problems in the > DataConverter.java > > source code > ------ > > for (int attr = 0; attr < nball; attr++) { --51 > if (ArrayUtils.contains(dataset.getIgnored(), attr)) { > continue; // IGNORED > } > > String token = tokens[attr].trim(); > > if ("?".equals(token)) { > // missing value > return null; > } > > if (dataset.isNumerical(aId)) { --63 > vector.set(aId++, Double.parseDouble(token)); > } else { // CATEGORICAL > vector.set(aId, dataset.valueOf(aId, token)); --66 > aId++; > } > ------- > Let feature descriptor be 9 I N L (Breiman Example) > 11 features, 1-9 Ignored, 10th is Numeric, 11th is label variable > (Is Breiman example really works based on web instruction ?) > > line 51 -- attr is #feature, 0-10 > aId is filtered feature #, 0-1 ( two non-Ignored features) > Problem in line 66 > if attr=10, Label feature > aId=1 > token=true > dataset.valueOf(aId, token) return -1 , for current code, CATEGORICAL > feature valueOf() kind mixed aId and attr concept. > > Just by changing line 66 > vector.set(aId, dataset.valueOf(aId, token)); --66 > to vector.set(aId, dataset.valueOf(attr, token)); > not working, because some validation fails (also attr, aId mixture). > > > > There might be things that I overlook, just some thoughts. > > > Sam >