NEWS | R Documentation |

In

`mob()`

using the`cluster`

argument with a`factor`

variable sometimes lead to`NA`

s in the covariance matrix estimate if empty categories occured in subgroups. The problem had been introduced in version 1.2-0 and has been fixed now.Methods for the

`sctest`

generic from the strucchange package are now dynamically registered if strucchange is attached. Alternatively, the methods can be called directly using their full names`sctest.constparty`

and`sctest.modelparty`

.The

`prune.modelparty`

function is now fully exported but it is also registered with the`prune`

generic from rpart.

New

`scale`

argument for`predict`

in`cforest`

. For simple regression forests, predicting the conditional mean by nearest neighbor weights with`scale = TRUE`

is now equivalent to the aggregation of means. The unscaled version proposed in <doi:10.1002/sim.1593> can be obtained with`scale = FALSE`

.

Bug fix for case weights in

`mob()`

in previous version (1.2-0) introduced a bug in the handling of proportionality weights. Both cases are handled correctly now.`glmtree`

can now handle`caseweights = TRUE`

correctly for`vcov`

other than the default`"opg"`

. Internally, the`glm`

objects are adjusted by correcting the dispersion estimate and the degrees of freedom.`lookahead`

did not work in the presence of missing values.Calling

`partykit::ctree`

did not work when partykit was not attached.`node_inner`

now allows to set a different`gpar(fontsize = ...)`

in the inner nodes compared to the overall tree.`splittest`

asked for Monte-Carlo p-values, even when the test statistic was used as criterion.

We welcome Heidi Seibold as co-author!

Internal re-organisation for

`ctree`

by means of new extensible tree infrastructure (available in`extree_data`

and`extree_fit`

). Certain parts of the new infrastructure are still experimental.`ctree`

is fully backward compatible.Use libcoin for computing linear test statistics and p-values for

`ctree`

.Use inum for binning (the new

`nmax`

argument).Quadratic test statistics for splitpoint selection are now available for

`ctree`

via`ctree_control(splitstat = "quadratic")`

.Maximally selected test statistics for variable selection are now available for

`ctree`

via`ctree_control(splittest = TRUE)`

.Missing values can be treated as a separate category, also for splits in numeric variables in

`ctree`

via`ctree_control(MIA = TRUE)`

.Permutation variable importance, including conditional variable importance, was added to partykit.

New

`offset`

argument in`ctree`

.New

`get_paths`

for computing paths to nodes.`node_barplot`

gained a`text`

argument that can be used to draw text labels for the percentages displayed.The

`margins`

used in`plot.party`

can now also be set by the user.

Bug fix in

`mob()`

if`weights`

are used and`caseweights = TRUE`

(the default). The statistics for the parameter instability tests were computed incorrectly and consequently the selection of splitting variables and also the stopping criterion were affected/incorrect.Avoid log(p) values of

`-Inf`

inside`mob()`

by replacing weighted averaging with naive averaging in the response surface regression output in case the p values are below machine precision.The

`as.party`

method for`rpart`

objects without any splits only returned a naked`partynode`

rather than a full`party`

. This has been corrected now.`nodeapply`

did not produce the same results for permutations of`ids`

. Spotted by Heidi Seibold.Out-of-bag predictions in

`predict.cforest`

were incorrect.`perm`

in`predict`

was only considered when`newdata`

was given. Spotted by Heidi Seibold.Don't try to search for binary splits in unordered factors with more than 31 levels. This potentially caused an integer overrun in previous versions.

`party::ctree()`

uses an approximation for binary split searches in unordered factors; thus, using party might be an alternative.

Proper support of quasi-families in

`glmtree`

and hence`palmtree`

.NA handling by following the majority was potentially incorrect in

`ctree`

.Minor speed improvements.

Breaking ties before variable selection was suboptimal for very small log-p-values.

Added a new function

`palmtree`

that fits partially additive (generalized) linear model trees. These employ model-based recursive partitioning (`mob`

) based on (generalized) linear models with some local (i.e., leaf-specific) and some global (i.e., constant throughout the tree) regression coefficients.Splits in ordinal variables are now represented correctly in the (still internal)

`list.rule`

method.Kaplan-Meier curves in

`"constparty"`

trees were plotted incorrectly due to use a wrong scaling of the x-axis. Spotted by Peter Calhoun <calhoun.peter@gmail.com>.Use

`quote(stats::model.frame)`

instead of`as.name("model.frame")`

.The

`as.party`

methods for`rpart`

and`Weka_tree`

now have a`data = TRUE`

argument so that by default the data is preserved in the`party`

object (instead of an empty model frame).The

`predict`

method for`cforest`

objects did not work for one-row data frames, fixed now.Added

`rot`

and`just`

arguments to`node_barplot`

for more fine control of x-axis labeling (e.g., with 45 degree rotation).

The partykit package has now been published in

*Journal of Machine Learning Research*, 16, 3905-3909. http://jmlr.org/papers/v16/hothorn15a.htmlAdded support for setting background in panel functions.

The

`as.list()`

method for`partynode`

objects erroneously created an object`thisnode`

in the calling environment which is avoided now.

Bug fix in

`plot()`

method for`constparty`

objects. In the previous partykit version clipping was accidentally also applied to the axes labels.For

`constparty`

objects`plot(..., type = "simple")`

did not work correctly whereas`plot(as.simpleparty(...))`

yielded the desired visualization. Now internally`as.simpleparty()`

is called also in the former case.The

`as.simpleparty()`

method now preserves p-values from`constparty`

objects (if any).Added a

`getCall()`

method for`"party"`

objects.In the

`predict()`

method for`"lmtree"`

and`"glmtree"`

objects the`offset`

(if any) was sometimes ignored. It is now always used in the prediction.

Import

`logrank_trafo`

from coin.

`nodeprune(..., ids = 1)`

did not prune the tree to the root node. Fixed now.`predict.cforest`

used`na.omit`

instead of`na.pass`

.`predict.party`

now features new`perm`

argument for permuting splits in specific variables (useful for computing permutation variable importances).`NAMESPACE`

updates.

The support for (generalized) linear model trees with just a constant regressor has been improved. Now

`lmtree(y ~ x1 + x2)`

is short for`lmtree(y ~ 1 | x1 + x2)`

, analogously for`glmtree()`

. Plotting now also works properly in this case.The

`as.party()`

method for`"rpart"`

objects did not work if one of the partitioning variables was a`"character"`

variable rather than a`"factor"`

. A suitable work-around has been added.The

`node_barplot()`

panel function can now also be used for multivariate responses, e.g., when all responses are numeric and on the same scale.The package now also includes a new data set

`HuntingSpiders`

which is essentially a copy of the`spider`

data from the package mvpart that is currently archived on CRAN. The documentation has been improved somewhat and is likely to change further to explain how the data has been transformed in De'ath (2002).The survival tree example for the GBSG2 data was broken due to the response being (incorrectly) also part of the explanatory variables. Fixed by using the latest Formula package (at least version 1.2-1).

Version 1.0-0 published. This version is described in the MLOSS paper accepted for publication by the Journal of Machine Learning Research today.

The unbiased version of

`cforest`

(with`replace = FALSE`

) is now the default (as in party).Register all S3 methods in

`NAMESPACE`

.

Extended

`mob()`

interface by a`cluster`

argument. This can be a vector (numeric, integer, factor) with cluster IDs that are then passed on to the 'fit' function (if supported) and used for clustering the covariance matrix in the parameter stability tests.`lmtree()`

and`glmtree()`

hence both gained a`cluster`

argument which is used only for cluster covariances but not for the model estimation (i.e., corresponding to a working independence model).Optionally, the parameters' variance-covariance matrix in

`mob()`

can now be estimated by the sandwich matrix instead of the default outer-product-of-gradients (OPG) matrix or the information matrix.Reimplementation of

`cforest()`

available with extended prediction facilities. Both the internal representation and the user interface are still under development are likely to change in future versions.Added multicore support to

`mob()`

,`ctree()`

, and`cforest()`

. If control argument`cores`

is specified (e.g.,`cores = 4`

) then the search for the best variable or split point (often involving numerous model fits in`mob()`

or resampling in`ctree()`

) is carried out using`parallel::mclapply()`

rathern than sequential`for()`

or`sapply()`

. Additionally, other`applyfun`

s can be provided, e.g., using networks of workstations etc.Bug fix in

`mob()`

that occurred when regressor variables and partitioning variables overlapped and were not sorted in the underlying model frame.

mvpart was archived 2014-12-15.

Fixed an uninitialized memory issue reported by valgrind.

partykit now depends on R version >= 3.1.0 in order to import the

`depth()`

generic from the grid package.The print methods for

`party`

/`partynode`

objects with only a root node was modified. Now, the terminal panel function is also applied if there is only a root node (while previously it was not).-
`ctree()`

now catches`sum(weights) <= 1`

situations before they lead to an error. Code from suggested packages is included by using

`::`

syntax as required by recent R versions.Argument

`ytrafo`

of`ctree()`

can now be a function which will be updated in every node.A small demo briefly illustrating some memory and speed properties has been added. It can be run interactively via

`demo("memory-speed", package = "partykit").`

Section 3 of the "constparty" vignette now shows how properties of a new tree algorithm can be assessed by using partykit building blocks.

Major improved version of partykit. The previously existing functions in the package were tested and enhanced, new functions and extensive vignettes added.

Extended and improved introductory documentation. The basic classes and class constructors

`partynode`

/`partysplit`

/`party`

are introduced in much more detail now in`vignette("partykit", package = "partykit")`

.The class

`constparty`

(inheriting from`party`

) for representing`party`

objects with constant fits in the nodes (along with coercion methods for`rpart`

,`J48`

, etc.) is now described in more detail in the new`vignette("constparty", package = "partykit")`

.The package now includes a reimplementation of the model-based recursive partitioning algorithm (MOB) using partykit infrastructure. The generic algorithm, the corresponding convenience interfaces

`lmtree()`

and`glmtree()`

as well as various illustrations and possible extensions are described in detail in the new`vignette("mob", package = "partykit")`

.Improved implementation of conditional inference trees (CTree), see the new

`vignette("ctree", package = "partykit")`

for details.New

`nodeprune()`

generic for pruning nodes in all`party`

trees and`partynode`

objects.Deal with empty levels in

`ctree()`

for`teststat = "quad"`

(bug reported by Wei-Yin Loh <loh_at_stat.wisc.edu>).In

`predict()`

method for`constparty`

objects,`type = "prob"`

now returns ECDF for numeric responses and`type = "response"`

the (weighted) mean.New panel function

`node_ecdf()`

for plotting empirical cumulative distribution functions in the terminal leaves of`constparty`

trees.

Bug fix in

`as.party()`

method for J48 trees with ordered factors.

Fix C code problems reported by clang under OS X.

Added

`node_surv()`

for plotting survival ctrees. Accompanying infrastructure for survival trees was enhanced.`ctree()`

now checks for (and does not allow)`x >= max(x)`

splits.

Added ipred to the list of suggested packages due to usage of GlaucomaM and GBSG2 data in tests/examples.

The

`node_terminal()`

panel-generating function is now customizable by a FUN argument that is passed to`formatinfo()`

.The

`plot()`

method for`simpleparty`

object now sets up a formatting function passed to`formatinfo()`

, both in`print()`

and`plot()`

.Fixed bug in

`pmmlTreeModel()`

for processing label IDS in splits when not all levels are present.Cleaned up unused variables in C code and partial argument matching in R code.

First CRAN release.

See

`vignette("partykit", package = "partykit")`

for a (somewhat rough) introduction to the package and its classes/methods.