I wrote some code for this a while back, pretty sure it didn't need access to anything private in the decision tree / random forest model. If people want it added to the api I can put together a PR.
I think it's important to have separately parseable operators / operands though. E.g "lhs":0,"op":"<=","rhs":-35.0 On Aug 28, 2015 12:03 AM, "Manish Amde" <[email protected]> wrote: > Hi James, > > It's a good idea. A JSON format is more convenient for visualization > though a little inconvenient to read. How about toJson() method? It might > make the mllib api inconsistent across models though. > > You should probably create a JIRA for this. > > CC: dev list > > -Manish > > On Aug 26, 2015, at 11:29 AM, Murphy, James <[email protected]> > wrote: > > Hey all, > > > > In working with the DecisionTree classifier, I found it difficult to > extract rules that could easily facilitate visualization with libraries > like D3. > > > > So for example, using : print(model.toDebugString()), I get the following > result = > > > > If (feature 0 <= -35.0) > > If (feature 24 <= 176.0) > > Predict: 2.1 > > If (feature 24 = 176.0) > > Predict: 4.2 > > Else (feature 24 > 176.0) > > Predict: 6.3 > > Else (feature 0 > -35.0) > > If (feature 24 <= 11.0) > > Predict: 4.5 > > Else (feature 24 > 11.0) > > Predict: 10.2 > > > > But ideally, I could see results in a more parseable format like JSON: > > > > { > > "node": [ > > { > > "name":"node1", > > "rule":"feature 0 <= -35.0", > > "children":[ > > { > > "name":"node2", > > "rule":"feature 24 <= 176.0", > > "children":[ > > { > > "name":"node4", > > "rule":"feature 20 < 116.0", > > "predict": 2.1 > > }, > > { > > "name":"node5", > > "rule":"feature 20 = 116.0", > > "predict": 4.2 > > }, > > { > > "name":"node5", > > "rule":"feature 20 > 116.0", > > "predict": 6.3 > > } > > ] > > }, > > { > > "name":"node3", > > "rule":"feature 0 > -35.0", > > "children":[ > > { > > "name":"node7", > > "rule":"feature 3 <= 11.0", > > "predict": 4.5 > > }, > > { > > "name":"node8", > > "rule":"feature 3 > 11.0", > > "predict": 10.2 > > } > > ] > > } > > > > ] > > } > > ] > > } > > > > Food for thought! > > > > Thanks, > > > > Jim > > > >
