GBM can fail when it encounters a bin with just one single value and NAs

[exalate-issue-sync]

A regression was introduced in PUBDEV-7486. GBM can sometimes fail if histogram bin only has a single value and the rest of it is NAs. Reproduced on the Springleaf dataset:

{noformat}> unique(DF[,"VAR_0018"])
[1] 0 NA{noformat}

Exception (needs to have assertions enabled):

{noformat}[2020-04-28T05:28:00.878Z] java.lang.AssertionError: broken histo range VAR_0018:0.0-1.0 step=1.0 nbins=1 isInt=1
[2020-04-28T05:28:00.878Z] at hex.tree.DTree$UndecidedNode.scoreCols(DTree.java:345)
[2020-04-28T05:28:00.878Z] at hex.tree.DTree$UndecidedNode.(DTree.java:324)
[2020-04-28T05:28:00.878Z] at hex.tree.gbm.GBM$GBMDriver.growTrees(GBM.java:473)
[2020-04-28T05:28:00.878Z] at hex.tree.gbm.GBM$GBMDriver.buildNextKTrees(GBM.java:385)
[2020-04-28T05:28:00.878Z] at hex.tree.SharedTree$Driver.scoreAndBuildTrees(SharedTree.java:442)
[2020-04-28T05:28:00.878Z] at hex.tree.SharedTree$Driver.computeImpl(SharedTree.java:362)
[2020-04-28T05:28:00.878Z] at hex.ModelBuilder$Driver.compute2(ModelBuilder.java:248)
[2020-04-28T05:28:00.878Z] at water.H2O$H2OCountedCompleter.compute(H2O.java:1557)
[2020-04-28T05:28:00.878Z] at jsr166y.CountedCompleter.exec(CountedCompleter.java:468)
[2020-04-28T05:28:00.878Z] at jsr166y.ForkJoinTask.doExec(ForkJoinTask.java:263)
[2020-04-28T05:28:00.878Z] at jsr166y.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:974)
[2020-04-28T05:28:00.878Z] at jsr166y.ForkJoinPool.runWorker(ForkJoinPool.java:1477)
[2020-04-28T05:28:00.878Z] at jsr166y.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:104){noformat}

[h2o-ops]

JIRA Issue Migration Info

Jira Issue: PUBDEV-7517
Assignee: Michal Kurka
Reporter: Michal Kurka
State: Resolved
Fix Version: 3.30.0.3
Attachments: N/A
Development PRs: Available

Linked PRs from JIRA

#4590