h2o.gbm interaction_constraints only builds single-depth trees

[exalate-issue-sync]

I was testing using the example in the documentation: [https://docs.h2o.ai/h2o/latest-stable/h2o-docs/data-science/algo-params/interaction_constraints.html|https://docs.h2o.ai/h2o/latest-stable/h2o-docs/data-science/algo-params/interaction_constraints.html|smart-link] Although I switched from {{h2o.xgboost}} to {{h2o.gbm}}.

Every tree that gets built is single-depth. I tried expanding the possible predictors to include all available (non-response) variables and still they were all single-depth. Commenting out this argument results in trees with > 1 depth.

{noformat}prostate_gb <- h2o.gbm(y = response,
interaction_constraints = list(list("AGE", "DCAPS")),
seed = 1234,
training_frame = prostate)

prostate_gb@model$model_summary$max_depth
[1] 1

prostate_gb <- h2o.gbm(y = response,
interaction_constraints = list(list("DPROS", "GLEASON", "VOL", "PSA", "AGE", "DCAPS")),
seed = 1234,
training_frame = prostate)

prostate_gb@model$model_summary$max_depth
[1] 1

prostate_gb <- h2o.gbm(y = response,
seed = 1234,
training_frame = prostate)

prostate_gb@model$model_summary$max_depth
[1] 5 {noformat}

I found the unit test for this functionality and ran the example: [https://github.com/h2oai/h2o-3/blob/6758ed00b5200c782cd2bbebf0094374757dc472/h2o-r/tests/testdir_algos/gbm/runit_GBM_interaction_constraints.R|https://github.com/h2oai/h2o-3/blob/6758ed00b5200c782cd2bbebf0094374757dc472/h2o-r/tests/testdir_algos/gbm/runit_GBM_interaction_constraints.R|smart-link]

The test passes, but I believe it is because every tree was single-depth, so the interaction constraints were only inadvertently met.

[h2o-ops]

JIRA Issue Details

Jira Issue: PUBDEV-8901
Assignee: Adam Valenta
Reporter: Paul Donnelly
State: Resolved
Fix Version: 3.38.0.3
Attachments: N/A
Development PRs: Available

[h2o-ops]

Linked PRs from JIRA

#6416
https://github.com/h2oai/h2oai-serving/pull/1135