cgam: An R Package for the Constrained Generalized Additive Model

The cgam package contains routines to fit the generalized additive model where the components may be modeled with shape and smoothness assumptions. The main routine is cgam and nineteen symbolic routines are provided to indicate the relationship between the response and each predictor, which satisfi...

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Main Authors: Xiyue Liao, Mary C. Meyer
Format: Article
Language:English
Published: Foundation for Open Access Statistics 2019-05-01
Series:Journal of Statistical Software
Subjects:
Online Access:https://www.jstatsoft.org/index.php/jss/article/view/2712
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author Xiyue Liao
Mary C. Meyer
author_facet Xiyue Liao
Mary C. Meyer
author_sort Xiyue Liao
collection DOAJ
description The cgam package contains routines to fit the generalized additive model where the components may be modeled with shape and smoothness assumptions. The main routine is cgam and nineteen symbolic routines are provided to indicate the relationship between the response and each predictor, which satisfies constraints such as monotonicity, convexity, their combinations, tree, and umbrella orderings. The user may specify constrained splines to fit the individual components for continuous predictors, and various types of orderings for the ordinal predictors. In addition, the user may specify parametrically modeled covariates. Two-way interactions between continuous variables, where the relationship with the response is constrained to be monotone, are modeled with "warpedplane splines." The set over which the likelihood is maximized is a polyhedral convex cone, and a least-squares solution is obtained by projecting the data vector onto the cone. For generalized models, the fit is obtained through iteratively re-weighted cone projections. The cone information criterion (CIC) is provided and may be used to compare fits for combinations of variables and shapes. The graphical routine plotpersp will plot an estimated mean surface for a selected pair of predictors, given an object fitted with cgam. This package is available from the Comprehensive R Archive Network (CRAN) at https://CRAN.R-project.org/package=cgam.
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spelling doaj.art-e8af956dfc3a44e9a2d270f2b56156382022-12-21T20:30:29ZengFoundation for Open Access StatisticsJournal of Statistical Software1548-76602019-05-0189112410.18637/jss.v089.i051292cgam: An R Package for the Constrained Generalized Additive ModelXiyue LiaoMary C. MeyerThe cgam package contains routines to fit the generalized additive model where the components may be modeled with shape and smoothness assumptions. The main routine is cgam and nineteen symbolic routines are provided to indicate the relationship between the response and each predictor, which satisfies constraints such as monotonicity, convexity, their combinations, tree, and umbrella orderings. The user may specify constrained splines to fit the individual components for continuous predictors, and various types of orderings for the ordinal predictors. In addition, the user may specify parametrically modeled covariates. Two-way interactions between continuous variables, where the relationship with the response is constrained to be monotone, are modeled with "warpedplane splines." The set over which the likelihood is maximized is a polyhedral convex cone, and a least-squares solution is obtained by projecting the data vector onto the cone. For generalized models, the fit is obtained through iteratively re-weighted cone projections. The cone information criterion (CIC) is provided and may be used to compare fits for combinations of variables and shapes. The graphical routine plotpersp will plot an estimated mean surface for a selected pair of predictors, given an object fitted with cgam. This package is available from the Comprehensive R Archive Network (CRAN) at https://CRAN.R-project.org/package=cgam.https://www.jstatsoft.org/index.php/jss/article/view/2712constrained generalized additive modelisotonic regressionspline regressionpartial lineariteratively re-weighted cone projectionrgraphical routine
spellingShingle Xiyue Liao
Mary C. Meyer
cgam: An R Package for the Constrained Generalized Additive Model
Journal of Statistical Software
constrained generalized additive model
isotonic regression
spline regression
partial linear
iteratively re-weighted cone projection
r
graphical routine
title cgam: An R Package for the Constrained Generalized Additive Model
title_full cgam: An R Package for the Constrained Generalized Additive Model
title_fullStr cgam: An R Package for the Constrained Generalized Additive Model
title_full_unstemmed cgam: An R Package for the Constrained Generalized Additive Model
title_short cgam: An R Package for the Constrained Generalized Additive Model
title_sort cgam an r package for the constrained generalized additive model
topic constrained generalized additive model
isotonic regression
spline regression
partial linear
iteratively re-weighted cone projection
r
graphical routine
url https://www.jstatsoft.org/index.php/jss/article/view/2712
work_keys_str_mv AT xiyueliao cgamanrpackagefortheconstrainedgeneralizedadditivemodel
AT marycmeyer cgamanrpackagefortheconstrainedgeneralizedadditivemodel