h2oaiGH-16149: fix gam rebalance bug (h2oai#16153)

* add R test that reproduce the error.

* add more to test.

* h2oaiGH-16149: fixed key passed to rebalance dataset to avoid collision.

* Adopt adam code review comments.

Co-authored-by: Veronika Maurerová <[email protected]>

Author: wendycwong

h2o-algos/src/main/java/hex/gam/GAM.java

@@ -927,7 +927,7 @@ public void computeImpl() {
       if (error_count() > 0)   // if something goes wrong, let's throw a fit
         throw H2OModelBuilderIllegalArgumentException.makeFromBuilder(GAM.this);
       // add gamified columns to training frame
-      Frame newTFrame = new Frame(rebalance(adaptTrain(), false, _result+".temporary.train"));
+      Frame newTFrame = new Frame(rebalance(adaptTrain(), false, Key.make()+".temporary.train"));
       verifyGamTransformedFrame(newTFrame);
 
       if (error_count() > 0)   // if something goes wrong during gam transformation, let's throw a fit again!
@@ -937,7 +937,7 @@ public void computeImpl() {
         int[] singleGamColsCount = new int[]{_cubicSplineNum, _iSplineNum, _mSplineNum};
         _valid = rebalance(adaptValidFrame(_parms.valid(), _valid, _parms, _gamColNamesCenter, _binvD,
                         _zTranspose, _knots, _zTransposeCS, _allPolyBasisList, _gamColMeansRaw, _oneOGamColStd, singleGamColsCount),
-                false, _result + ".temporary.valid");
+                false, Key.make() + ".temporary.valid");
       }
       DKV.put(newTFrame); // This one will cause deleted vectors if add to Scope.track
       Frame newValidFrame = _valid == null ? null : new Frame(_valid);

h2o-r/tests/testdir_algos/gam/runit_GH_16149_gam_row_error.R

@@ -0,0 +1,53 @@
+setwd(normalizePath(dirname(R.utils::commandArgs(asValues=TRUE)$"f")))
+source("../../../scripts/h2o-r-test-setup.R")
+
+library(data.table)
+
+# This test was provided by a customer.  No exit condition is needed as
+# the test before my fix always failed.  As long as this test completes
+# successfully, it should be good enough.
+test.gam.dataset.error <- function(n) {
+  sum_insured <- seq(1, 200000, length.out = n)
+  d2 <-
+    data.table(
+      sum_insured = sum_insured,
+      sqrt = sqrt(sum_insured),
+      sine = sin(2 * pi * sum_insured / 40000)
+    )
+  d2[, sine := 0.3 * sqrt * sine , ]
+  d2[, y := pmax(0, sqrt + sine) , ]
+  
+  d2[, x := sum_insured]
+  d2[, x2 := rev(x) , ] # flip axis
+  
+  # import the dataset
+  h2o_data2 <- as.h2o(d2)
+  
+  model2 <-
+    h2o.gam(
+      y = "y",
+      gam_columns = c("x2"),
+      bs = c(2),
+      spline_orders = c(3),
+      splines_non_negative = c(F),
+      training_frame = h2o_data2,
+      family = "tweedie",
+      tweedie_variance_power = 1.1,
+      scale = c(0),
+      lambda = 0,
+      alpha = 0,
+      keep_gam_cols = T,
+      non_negative = TRUE,
+      num_knots = c(10)
+    )
+  print("model building completed.")
+}
+
+test.model.gam.dataset.error <- function() {
+  # test for n=1005
+  test.gam.dataset.error(1005)
+  # test for n=1001;
+  test.gam.dataset.error(1001)
+}
+
+doTest("General Additive Model dataset size 1001 and 1005 error", test.model.gam.dataset.error)