glmbayes provides independent and identically distributed (iid) samples for Bayesian Generalized Linear Models (GLMs). Its primary interface, glmb(), serves as a Bayesian analogue to R's glm() function, supporting Gaussian, Poisson, Binomial, and Gamma families under log-concave likelihoods. Sampling for most models is performed using accept-reject methods based on likelihood subgradients (Nygren and Nygren, 2006). For Gaussian models, the package also includes lmb(), a Bayesian counterpart to R's lm().
The package includes a rich set of supporting tools for prior specification, model diagnostics, and method functions that mirror those for lm() and glm(). Most functions are extensively documented, and a comprehensive set of vignettes are available to guide users through the package's capabilities.
This repository is 0.9.6 in development. The current CRAN release is version 0.9.5 (CRAN). The GitHub repository holds the source; R-Universe builds binaries from it. See NEWS.md for changes.
CRAN (release 0.9.5)
install.packages("glmbayes")GitHub / R-Universe (install from both CRAN and R-Universe repositories if you want R-Universe binaries or faster mirrors):
install.packages("glmbayes",
repos = c("https://cloud.r-project.org",
"https://knygren.r-universe.dev"))Prebuilt binaries from CRAN (0.9.5) and R-Universe are built without OpenCL GPU support. For the CRAN release, OpenCL requires installing from source on a system with OpenCL development files available. To set up GPU acceleration, follow
Chapter 16 — Large models: GPU acceleration using OpenCL https://knygren.r-universe.dev/articles/glmbayes/Chapter-16.html
library(glmbayes)
# Dobson (1990), p. 93: Randomized Controlled Trial
counts <- c(18,17,15,20,10,20,25,13,12)
outcome <- gl(3,1,9)
treatment <- gl(3,3)
print(d.AD <- data.frame(treatment, outcome, counts))
## Classical glm
glm.D93 <- glm(counts ~ outcome + treatment,
family = poisson())
## Bayesian glmb
# Step 1: Set up prior
ps <- Prior_Setup(counts ~ outcome + treatment, family = poisson())
mu <- ps$mu
V <- ps$Sigma
# Step 2: Fit using glmb
glmb.D93 <- glmb(counts ~ outcome + treatment,
family = poisson(),
pfamily = dNormal(mu = mu, Sigma = V))
summary(glmb.D93)
As with glm(), models are defined by a formula for the linear predictor and a family() describing the likelihood and
link. In addition, glmb() requires a pfamily object specifying the prior.
The primary table below covers priors on the regression coefficients β. The standard prior for
all families is dNormal. The conjugate priors dBeta and dGamma(Inv_Dispersion = FALSE) provide
closed-form IID posterior draws for intercept-only models with an identity link.
| Likelihood family | Link functions | Compatible pfamilies (coefficient priors) |
|---|---|---|
| Gaussian | identity | dNormal, dNormal_Gamma, dIndependent_Normal_Gamma |
| Poisson / Quasi-Poisson | log | dNormal |
| Poisson | identity (intercept-only) | dGamma(Inv_Dispersion = FALSE) — conjugate Gamma–Poisson rate prior |
| Binomial / Quasi-Binomial | logit, probit, cloglog | dNormal |
| Binomial | identity (intercept-only) | dBeta — conjugate Beta–Binomial probability prior |
| Gamma | log | dNormal |
| Gamma | identity (intercept-only) | dGamma(Inv_Dispersion = FALSE) — conjugate Gamma–Gamma rate prior |
dNormal_Gamma and dIndependent_Normal_Gamma also model precision jointly with the coefficients;
see the precision/dispersion table below.
dGamma(Inv_Dispersion = TRUE) (the default when Inv_Dispersion is omitted) places a Gamma prior
on the inverse dispersion 1/φ with the regression coefficients β held fixed. This is the
precision prior used in Gibbs sampling steps for dispersion estimation.
| Likelihood family | Link | Compatible pfamilies (precision prior) |
|---|---|---|
| Gaussian | identity | dGamma — prior on 1/σ² (precision) |
| Gamma | log | dGamma — prior on 1/φ (shape / dispersion) |
dNormal_Gamma and dIndependent_Normal_Gamma model β and precision jointly in a single
conjugate step, avoiding the need for a separate Gibbs precision update.
For a default, data‑aligned prior using the same formula and family as glm(), call Prior_Setup(formula, family, data = ..., ...).
The returned list includes default settings for the following:
- mu, Sigma — Zellner‑style normal prior components for use with most priors
- Additional Gaussian‑specific calibration components:
dispersionfor use with thedNormal()prior (gaussian and Gamma families)Sigma_0,shapeandratefor use with thedNormal_Gamma()priorshape_INGandratefor use withdIndependent_Normal_Gamma()priorshape,rate_gammaandcoefficientsfor use with thedGamma()precision prior
- Conjugate prior calibration components (intercept-only models):
conj_beta(shape1,shape2,beta) for use withdBeta()(Binomial/identity)conj_poisson(shape,rate,beta) for use withdGamma(Inv_Dispersion = FALSE)(Poisson/identity)
Optional arguments adjust prior weight, centering, and related settings (see the function help and vignette Chapter 04).
Assuming ps <- Prior_Setup(...):
-
Non‑Gaussian families (log/logit/probit/cloglog links):
UsedNormal(mu = ps$mu, Sigma = ps$Sigma).
(For Gamma GLMs, also supplydispersionfrom the fitted GLM or fromps; seeexample("glmb").) -
Binomial — conjugate Beta prior (identity link, intercept-only):
UsedBeta(shape1 = ps$conj_beta$shape1, shape2 = ps$conj_beta$shape2, beta = ps$conj_beta$beta). -
Poisson — conjugate Gamma rate prior (identity link, intercept-only):
UsedGamma(shape = ps$conj_poisson$shape, rate = ps$conj_poisson$rate, beta = ps$conj_poisson$beta, Inv_Dispersion = FALSE). -
Gaussian — normal prior with known dispersion:
UsedNormal(mu = ps$mu, Sigma = ps$Sigma, dispersion = ps$dispersion). -
Gaussian — conjugate Normal–Gamma:
UsedNormal_Gamma(mu = ps$mu, Sigma_0 = ps$Sigma_0, shape = ps$shape, rate = ps$rate). -
Gaussian — independent Normal–Gamma:
UsedIndependent_Normal_Gamma(mu = ps$mu, Sigma = ps$Sigma, shape = ps$shape_ING, rate = ps$rate). -
Gaussian / Gamma — precision prior (coefficients fixed, for Gibbs):
Withrate_dg <- if (!is.null(ps$rate_gamma)) ps$rate_gamma else ps$rate, use
dGamma(shape = ps$shape, rate = rate_dg, beta = ps$coefficients).
The default priors have limiting behaviors that produce estimates resembling classical estimates as priors get weak (see documentation and vignettes for details).
All supported models have log‑concave likelihoods, enabling efficient iid sampling via enveloping functions and subgradient‑based accept–reject algorithms, especially for models lacking standard iid samplers.
Use example() and demo() to explore built-in examples and demos for supported families and links:
## Bayesian linear regression
example("lmb")
## Bayesian generalized linear models
example("glmb")
## Beta-Binomial conjugacy: dBeta() prior; Bechdel test (requires bayesrules)
## See also: vignette("Chapter-02-S03", package = "glmbayes")
demo("Ex_12_BetaBinomial")
## Gamma-Poisson conjugacy: dGamma(Inv_Dispersion=FALSE); bike counts + heart
## transplant mortality (requires bayesrules; Appendix A requires LearnBayes)
## See also: vignette("Chapter-02-S04", package = "glmbayes")
demo("Ex_13_GammaPoisson")
## Predictions for fitted glmb objects (newdata, type, etc.)
example("predict.glmb")
## Deviance residuals and simulate() for posterior predictive checks (menarche)
example("residuals.glmb")
## Two-block Gibbs sampler compared with iid sampling (linear model)
example("rlmb")
## Default prior specification using Prior_Setup
example("Prior_Setup")
## Matrix-input GLM example with an informative prior
example("rglmb")
## Two-step Boston example: estimates and summarizes models with unknown
## dispersion using dGamma priors via rGamma_reg, rglmb, rlmb, glmb, and lmb
example("summary.rGamma_reg")
## High-dimensional Gaussian model (14 predictors) with GPU acceleration (requires OpenCL)
example("Boston_centered")
## High-dimensional binomial model (14 predictors) with GPU acceleration (requires OpenCL)
example("Cleveland")
## Hierarchical linear model (Rubin/Gelman 8-schools) via rlmb
demo("Ex_07_Schools")
## Hierarchical generalized linear model (Poisson BikeSharing) via rglmb
demo("Ex_09_BikeSharingPoisson")
## Detailed simulation pipeline for rNormalGLM models (JASA 2006; Vignette Chapter A05)
example("rNormalGLM_std")
## Detailed simulation pipeline for rIndepNormalGammaReg models (Vignette Chapter A07)
example("rIndepNormalGammaReg_std")
For generalized linear models where well known sampling methods are unavailable, sampling follows the
framework from Nygren and Nygren (2006), using likelihood subgradients to construct enveloping functions for
the posterior distribution. When the posterior is approximately normal, the expected number of draws per
acceptance is bounded as per that paper and as discussed in our vignettes.
Dispersion can be sampled via rGamma_reg() (standalone) or jointly with coefficients via
rNormalGamma_reg() and rindepNormalGamma_reg().
The implemented algorithms tend to have acceptable performance on CPUs up to around 10-14 dimensions. For larger models, the envelope construction is embarrassingly parallel. To accelerate envelope construction in such cases, the package provides optional GPU acceleration using OpenCL. This requires that users have GPU enabled machines and an OpenCL installation. These features are discussed in more detail in two of our vignettes.
The glmbayes package includes a comprehensive set of vignettes organized into five major parts. These vignettes guide users from introductory material through applied modeling, advanced topics, and the underlying simulation methods that support the package.
Overview of the package, its design philosophy, single-parameter conjugate models, and the basic workflow for fitting Bayesian linear and generalized linear models.
-
Chapter 00 - Introduction
https://knygren.r-universe.dev/articles/glmbayes/Chapter-00.html -
Chapter 01 - Getting Started with glmbayes
https://knygren.r-universe.dev/articles/glmbayes/Chapter-01.html -
Chapter 02 — Conjugate inference for single parameters (S01–S05)
Start with Chapter 02-S01; then S02 (Normal–Normal), S03 (Beta–Binomial), S04 (Gamma–Poisson), S05 (Gamma–Gamma).
These chapters focus on Bayesian linear regression (Gaussian family). Topics include lmb() fitting, Prior_Setup(), posterior predictive checks (bayesplot), deviance residuals and model summaries, bayestestR-style summaries, and the bridge to Bayesian GLMs in Part 3.
-
Chapter 03 — Estimating Bayesian linear models
https://knygren.r-universe.dev/articles/glmbayes/Chapter-03.html -
Chapter 04 — Tailoring priors — leveraging the Prior_Setup function
https://knygren.r-universe.dev/articles/glmbayes/Chapter-04.html -
Chapter 05 — Model predictions and posterior predictive checks (+ bayesplot
ppc_*)
https://knygren.r-universe.dev/articles/glmbayes/Chapter-05.html -
Chapter 06 — Deviance residuals, model statistics and posterior inference (+ bayestestR)
https://knygren.r-universe.dev/articles/glmbayes/Chapter-06.html
This part presents Bayesian GLMs across the major likelihood families, including binomial, quasi-binomial, Poisson, quasi-Poisson, and Gamma models. It covers model specification, link functions, log-concavity, diagnostics, interpretation of posterior results, and tooling (bayesplot, bayestestR) for visualization and summaries.
-
Chapter 07 — Foundations of GLMs — families, links, and log-concave likelihoods
https://knygren.r-universe.dev/articles/glmbayes/Chapter-07.html -
Chapter 08 — Estimating Bayesian generalized linear models
https://knygren.r-universe.dev/articles/glmbayes/Chapter-08.html -
Chapter 09 — Models for the Binomial family
https://knygren.r-universe.dev/articles/glmbayes/Chapter-09.html -
Chapter 10 — Models for the Poisson family
https://knygren.r-universe.dev/articles/glmbayes/Chapter-10.html -
Chapter 11 — Models for the Gamma family
https://knygren.r-universe.dev/articles/glmbayes/Chapter-11.html -
Chapter 12 — Visualizing posteriors with bayesplot
https://knygren.r-universe.dev/articles/glmbayes/Chapter-12.html -
Chapter 13 — Bayesian inference and decision making with bayestestR
https://knygren.r-universe.dev/articles/glmbayes/Chapter-13.html
These chapters explore more complex modeling scenarios and computational strategies, such as informative priors, two-block Gibbs sampling, linear and generalized linear mixed-effects models, models with unknown dispersion parameters, and large-scale model fitting using GPU acceleration using OpenCL.
-
Chapter 14 — Informative priors — centering and differential prior weights
https://knygren.r-universe.dev/articles/glmbayes/Chapter-14.html -
Chapter 15 — Estimating models with unknown dispersion parameters
https://knygren.r-universe.dev/articles/glmbayes/Chapter-15.html -
Chapter 16 — Large models: GPU acceleration using OpenCL
https://knygren.r-universe.dev/articles/glmbayes/Chapter-16.html -
Chapter 17 — Linear mixed-effects models
https://knygren.r-universe.dev/articles/glmbayes/Chapter-17.html -
Chapter 18 — Generalized linear mixed-effects models
https://knygren.r-universe.dev/articles/glmbayes/Chapter-18.html
This part documents the mathematical and algorithmic foundations of the package. Topics include estimation procedures, likelihood subgradient densities, envelope construction, accept-reject sampling, and technical reports on sampler design including implementation aspects for GPU acceleration using OpenCL.
-
Chapter A01 - A detailed overview of the glmbayes package
https://knygren.r-universe.dev/articles/glmbayes/Chapter-A01.html -
Chapter A02 - Overview of Estimation Procedures
https://knygren.r-universe.dev/articles/glmbayes/Chapter-A02.html -
Chapter A03 - Methods Available in glmbayes
https://knygren.r-universe.dev/articles/glmbayes/Chapter-A03.html -
Chapter A04 - Directional Tail Diagnostics for Prior-Posterior Disagreement
https://knygren.r-universe.dev/articles/glmbayes/Chapter-A04.html -
Chapter A05 - Simulation Methods - Likelihood Subgradient Densities
https://knygren.r-universe.dev/articles/glmbayes/Chapter-A05.html -
Chapter A06 - Accept-Reject Sampling for Dispersion in Gamma Regression
https://knygren.r-universe.dev/articles/glmbayes/Chapter-A06.html -
Chapter A07 - Accept-Reject Sampling for gaussian Regression models with independent normal-gamma priors
https://knygren.r-universe.dev/articles/glmbayes/Chapter-A07.html -
Chapter A08 - Overview of Envelope Related Functions
https://knygren.r-universe.dev/articles/glmbayes/Chapter-A08.html -
Chapter A09 - Parallel Sampling Implementation using RcppParallel
https://knygren.r-universe.dev/articles/glmbayes/Chapter-A09.html -
Chapter A10 - Accelerated EnvelopeBuild Implementation using OpenCL
https://knygren.r-universe.dev/articles/glmbayes/Chapter-A10.html -
Chapter A11 - Implementation Companion for Independent Normal-Gamma
https://knygren.r-universe.dev/articles/glmbayes/Chapter-A11.html -
Chapter A12 - Technical Derivations for Priors Returned by
Prior_Setup()
https://knygren.r-universe.dev/articles/glmbayes/Chapter-A12.html
Together, these vignettes form a comprehensive reference that supports users at all levels, from first-time Bayesian GLM users to researchers interested in the mathematical and computational details behind the samplers.
- S3 interface mirroring the structure of base glm()
- Posterior predictive checks via
pp_check()from the 'bayesplot' package for fittedglmbobjects - Accept-reject sampling for log-concave likelihoods
- Samplers for both fixed and variable dispersion
- Extensive vignettes to guide users through the package's capabilities
- Modular prior setup function
- Non-log-concave likelihoods are not currently supported
- R Mathlib (
nmath) usage from C: Today the package vendors local copies of selected R Mathlib routines and headers in*.csources. The plan is to switch to calling the samenmathfunctions that ship with R, via the supported linking/API path, so maintenance tracks base R instead of duplicating sources. - OpenCL / GPU code upstream: Routines currently living under the openclport and nmathopencl namespaces are slated to move into dedicated upstream packages. nmathopencl is already available on R-Universe; a CRAN release is targeted, after which glmbayes can depend on that package for a substantial share of OpenCL- and GPU-related functionality rather than carrying those implementations here.
- Conjugate priors for intercept-only GLMs: Add pfamily specifications
that supply conjugate priors for intercept-only
glm()-style models (a single mean structure / scalar linear predictor), complementing the existing prior families for general designs. - bayestestR integration: Add methods or small wrappers so bayestestR
summaries and diagnostics can be used with
glmb/lmbfits in the same way as with other Bayesian modeling workflows.
Further performance and algorithm work:
- Poisson speed (OpenCL and simulation): Precompute the log-factorial term
log(y!)once per observation and reuse it in both OpenCL envelope construction and accept-reject simulation, since it depends only on the response, to reduce redundantlgammaevaluation and improve performance for large Poisson models. - Grid selection (simulation): Precompute cumulative PLSD and use inverse CDF sampling (e.g. binary search) to select the grid component per candidate instead of scanning PLSD, improving the simulation loop when many candidates are evaluated.