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mgcv (version 1.9-4)

Mixed GAM Computation Vehicle with Automatic Smoothness Estimation

Description

Generalized additive (mixed) models, some of their extensions and other generalized ridge regression with multiple smoothing parameter estimation by (Restricted) Marginal Likelihood, Cross Validation and similar, or using iterated nested Laplace approximation for fully Bayesian inference. See Wood (2025) for an overview. Includes a gam() function, a wide variety of smoothers, 'JAGS' support and distributions beyond the exponential family.

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Version

Install

install.packages('mgcv')

Monthly Downloads

130,279

Version

1.9-4

License

GPL (>= 2)

Maintainer

Simon Wood

Last Published

November 7th, 2025

Functions in mgcv (1.9-4)

Censored Box-Cox Gaussian family

Internal functions for discretized model matrix handling

GAM Tweedie families

blas.thread.test

BLAS thread safety

bug.reports.mgcv

Reporting mgcv bugs.

Evaluate cyclic B spline basis

Choleski decomposition of a band diagonal matrix

Approximate hypothesis tests related to GAM fits

Update a strictly additive bam model for new data.

Generalized additive models for very large datasets

Deletion and rank one Cholesky factor update

Basis dimension choice for smooths

Additive Cox proportional hazard models with time varying covariates

Additive Cox Proportional Hazard Model

GAM censored Poisson family

Obtaining derivative w.r.t. linear predictor

Reduced version of Columbus OH crime data

GAM concurvity measures

GAM censored logistic distribution family for log-logistic AFT models

GAM censored normal family for log-normal AFT and Tobit models

exclude.too.far

Exclude prediction grid points too far from data

extract.lme.cov

Extract the data covariance matrix from an lme object

Form component of GAMM covariance matrix

Factor smooth interactions in GAMs

Detect linear dependencies of one matrix on another

Distribution families in mgcv

fix.family.link

Modify families for use in GAM fitting and checking

Stable evaluation of difference between Poisson c.d.f.s

Stable evaluation of difference between normal c.d.f.s

gam.convergence

GAM convergence and performance issues

FELSPLINE test function

Simple posterior simulation with gam fits

Setting GAM fitting defaults

Some diagnostics for a fitted gam model

Generalized additive models with integrated smoothness estimation

Specifying generalized additive models

P-IRLS GAM estimation with GCV, UBRE/AIC or RE/ML derivative calculation

GAM P-IRLS estimation with GCV/UBRE smoothness estimation (deprecated)

gam.fit5.post.proc

Post-processing output of gam.fit5

Scale parameter estimation in GAMs

Finding stable orthogonal re-parameterization of the square root penalty.

Transform derivatives wrt mu to derivatives wrt linear predictor

Identifiability side conditions for a GAM

Report gam smoothness estimates as variance components

Minimize GCV or UBRE score of a GAM using `outer' iteration

Simulate example data for GAMs

Objective functions for GAM smoothing parameter estimation

Generalized Additive Model Selection

Fitted gam object

Gamma location-scale model family

Calculating derivatives of log-likelihood wrt regression coefficients

Generalized Extreme Value location-scale model family

GAM Integrated Nested Laplace Approximation Newton Enhanced

identifiability

Identifiability constraints

Gumbel location-scale model family

Get named variable or evaluate expression from list or data.frame

Generalized Additive Mixed Models

Grouped families

Gaussian location-scale model family

Extract the diagonal of the influence/hat matrix for a GAM

Getting log generalized determinant of penalty matrices

Interpret a GAM formula

Starting values for multiple smoothing parameter estimation

linear.functional.terms

Linear functionals of a smooth in GAMs

Checking smooth basis dimension

Log Tweedie density evaluation

Are points inside boundary?

Just Another Gibbs Additive Modeller: JAGS support for mgcv.

Which of a set of points lie within a polygon defined region

Size of list elements

AIC and Log likelihood for a fitted GAM

magic.post.proc

Auxilliary information from magic fit

Sparse chol function

Obtain square roots of penalty matrices

Frequently Asked Questions for package mgcv

Stable Multiple Smoothing Parameter Estimation by GCV or UBRE

Mixed GAM Computation Vehicle with GCV/AIC/REML/NCV smoothness estimation and GAMMs by REML/PQL

Parallel computation in mgcv.

Basic linear programming

Missing data in GAMs

Functions for better-than-log positive parameterization

model.matrix.gam

Extract model matrix from GAM fit

Monotonicity constraints for a cubic regression spline

GAM multinomial logistic regression

Obtain a name for a new variable that is not already in use

Alternative to log parameterization for variance components

GAM negative binomial families

Multivariate normal additive models

Smallest square root of matrix

Default GAM plotting

Penalized Constrained Least Squares Fitting

Functions implementing a pdMat class for tensor product smooths

Overflow proof pdMat class for multiples of the identity matrix

Automatically place a set of knots evenly through covariate values

null.space.dimension

The basis of the space of un-penalized functions for a TPRS

The one standard error rule for smoother models

Extract the effective degrees of freedom associated with each penalty in a gam fit

Plot geographic regions defined as polygons

GAM ordered categorical family

Prediction from fitted Big Additive Model model

Generate inverse Gaussian random deviates

QQ plots for gam model residuals

Generate Tweedie random deviates

Evaluate the c.d.f. of a weighted sum of chi-squared deviates

Prediction from fitted GAM model

Generate from or evaluate multivariate normal or t densities.

Generalized Additive Model residuals

Print a Generalized Additive Model object.

Random effects in GAMs

Sinh-arcsinh location scale and shape model family

Single index models with mgcv

smooth.construct

Constructor functions for smooth terms in a GAM

Defining smooths in GAM formulae

Extract or modify diagonals of a matrix

GAM scaled t family for heavy tailed data

Shape constrained additive smooth models

smooth.construct.bs.smooth.spec

Penalized B-splines in GAMs

Compute truncated eigen decomposition of a symmetric matrix

smooth.construct.ad.smooth.spec

Adaptive smooths in GAMs

smooth.construct.ds.smooth.spec

Low rank Duchon 1977 splines

smooth.construct.gp.smooth.spec

Low rank Gaussian process smooths

smooth.construct.ps.smooth.spec

P-splines in GAMs

smooth.construct.sos.smooth.spec

Splines on the sphere

smooth.construct.cr.smooth.spec

Penalized Cubic regression splines in GAMs

smooth.construct.re.smooth.spec

Simple random effects in GAMs

smooth.construct.fs.smooth.spec

Factor smooth interactions in GAMs

smooth.construct.sz.smooth.spec

Constrained factor smooth interactions in GAMs

smooth.construct.so.smooth.spec

Soap film smoother constructer

smooth.construct.mrf.smooth.spec

Markov Random Field Smooths

spasm.construct

Experimental sparse smoothers

smooth.construct.tp.smooth.spec

Penalized thin plate regression splines in GAMs

Smooth terms in GAM

smooth.construct.t2.smooth.spec

Tensor product smoothing constructor

Prediction/Construction wrapper functions for GAM smooth terms

Alternatives to step.gam

smooth.construct.tensor.smooth.spec

Tensor product smoothing constructor

Convert a smooth to a form suitable for estimating as random effect

Extract smoothing parameter estimator covariance matrix from (RE)ML GAM fit

Generic function to provide extra information about smooth specification

totalPenaltySpace

Obtaining (orthogonal) basis for null space and range of the penalty matrix

Extract parameter (estimator) covariance matrix from GAM fit

trind.generator

Generates index arrays for upper triangular storage

find the unique rows in a matrix

Define alternative tensor product smooths in GAM formulae

tensor.prod.model.matrix

Row Kronecker product/ tensor product smooth construction

Summary for a GAM fit

Choleski decomposition of a tri-diagonal matrix

Define tensor product smooths or tensor product interactions in GAM formulae

Tweedie location scale family

Visualization of GAM objects

GAM zero-inflated (hurdle) Poisson regression family

Zero inflated (hurdle) Poisson location-scale model family

Predict.matrix.cr.smooth

Predict matrix method functions

Applying re-parameterization from log-determinant of penalty matrix to model matrix.

Re-parametrizing model matrix X

Setting up a list representing a block diagonal penalty matrix

Neighbourhood Cross Validation

GAM beta regression family

Prediction methods for smooth terms in a GAM

Level 5 fractional factorial designs

Predict.matrix.soap.film

Prediction matrix for soap film smooth

Find rank of upper triangular matrix