Type: Package
Title: A Simple Implementation and Demonstration of Gradient Boosting
Version: 0.1.1
Date: 2016-04-19
Description: A basic, clear implementation of tree-based gradient boosting designed to illustrate the core operation of boosting models. Tuning parameters (such as stochastic subsampling, modified learning rate, or regularization) are not implemented. The only adjustable parameter is the number of training rounds. If you are looking for a high performance boosting implementation with tuning parameters, consider the 'xgboost' package.
License: GPL-3
Depends: R (≥ 3.1.1), rpart (≥ 4.1-10)
Suggests: testthat
URL: https://github.com/dashaub/DidacticBoost
BugReports: https://github.com/dashaub/DidacticBoost/issues
ByteCompile: true
NeedsCompilation: no
LazyData: TRUE
RoxygenNote: 5.0.1
Packaged: 2016-04-19 01:46:08 UTC; david
Author: David Shaub [aut, cre]
Maintainer: David Shaub <davidshaub@gmx.com>
Repository: CRAN
Date/Publication: 2016-04-19 08:11:59

Simple Gradient Boosting

Description

Fit a simple, educational implementation of tree-based gradient boosting model.

Usage

fitBoosted(formula, data, iterations = 100, verbose = TRUE)

Arguments

formula

an object of class "formula" with a response but no interaction terms. The response variable should be a binomial factor that has values of 1 for a positive response or -1 for a negative or lack of response.

data

the dataframe containing the independent variables and the response

iterations

The number of training rounds for boosting.

verbose

should the current training round be printed to the console?

Value

An S3 object of class boosted. This includes

Examples

k <- kyphosis
k$Kyphosis <- factor(ifelse(k$Kyphosis == "present", 1L, -1L))
fit <- fitBoosted(Kyphosis ~ Age + Number + Start, data = k, iterations = 10)


Is the Object a Boosted Model

Description

Test the inheritance of an object

Usage

is.boosted(x)

Arguments

x

any R object

Value

TRUE if the object is a boosted model


Model Predictions

Description

Apply a fitted boosted model to newdata to form predictions. If no newdata is included, returned the fitted values of the model.

Usage

## S3 method for class 'boosted'
predict(object, newdata = NULL, ...)

Arguments

object

a boosted model returned from fitBoosted

newdata

the new independent variables to use for prediction. This should be a data frame.

...

additional arguments affecting the predictions produced (ignored).

Value

predict.boosted produces a numeric vector with the predicted classes from the boosted model.