figs() now carries the parent leaf’s value into the
two leaves created by splitting it. Predictions from any tree deeper
than one split were wrong before this fix.
Classification probabilities are no longer passed through a
logistic function. The engine fits squared error on the 0/1 encoding of
the outcome, so the sum of the leaf values already estimates the
probability of the second level; it is now clamped to the unit interval
instead. fitted_values is clamped the same way, so it
agrees with predict().
predict() now rebuilds the model frame from the
fitted terms, so a formula with a transformed term such as
y ~ log(x) can be predicted from. It previously failed with
a missing-predictor error.
A matrix-valued term such as poly(x, 2) raised a
cryptic “missing value where TRUE/FALSE needed” during fitting; it is
now rejected with a clear message.
figs() gained subset and
na.action arguments, which were previously swallowed by
... and silently ignored. Passing weights now
raises an error rather than fitting an unweighted model in
silence.
A model that accepts no split at all predicts the outcome mean instead of zero. In classification this was a probability of zero for every observation.
Integer predictors with large values no longer overflow when the candidate cutpoints are computed.
Numeric cutpoints above the 30-candidate cap are now quantiles of the sample rather than of its distinct values, so they follow the density of the data.
Factor predictors are judged by the levels present in a node rather than by the declared level set, so a factor carrying many unused levels is no longer skipped as if it had too many levels.
A missing value in a predictor at prediction time raises a clear
error, and a factor level unseen in training is rejected the way other
stats model functions reject it, instead of failing deep
inside the tree traversal.
predict() rejects an unsupported type
instead of quietly returning numeric predictions.
bagging_figs() records the mode that was actually
fitted. A factor outcome with the default
mode = "regression" produced an ensemble that returned
numeric scores instead of class predictions. Bagged classification also
averages member probabilities rather than hard labels, and supports
type = "prob". A character outcome is converted to a factor
once, so a bootstrap resample that misses the minority class no longer
aborts the fit.
fit_figs() no longer drops a predictor genuinely
named .outcome.
plot() validates style and
tree_idx instead of rendering the wrong style silently or
failing with an internal error on NA. The
"classic" style labels leaves dy =, like the
other styles, because a leaf holds one tree’s contribution rather than
the prediction.
Registering the parsnip model is now idempotent, so
reloading the package in a live session no longer errors.
figs_tree() gained an engine argument
defaulting to "figsr", and an update() method,
so specifications behave like the rest of parsnip.
print() reports which predictors actually carry a
split, and summary() states that classification leaf values
are contributions to the probability of the second class.
Description field no longer quotes acronyms,
following the request from CRAN.parsnip integration and bagging, and its
example data no longer draws the outcome independently of the
predictors.First release.
figs() fits Fast Interpretable Greedy-Tree Sums for
regression and two-class classification, growing a sum of shallow trees
by greedily taking the split that most reduces residual impurity,
whether that split opens a new tree or deepens an existing one.
figs_tree() registers the model with
parsnip, so FIGS can be used inside tidymodels
workflows. max_splits() and max_trees()
provide dials parameter objects for tuning;
min_n reuses dials::min_n().
summary() prints the tree sum as IF-THEN decision
rules and plot() draws the trees, in a
"scientific", "modern" or
"classic" style.
figsr_importance() ranks predictors by the total
residual sum-of-squares reduction attributable to each of them.
bagging_figs() fits a bootstrap ensemble of FIGS
models.