···66Description: A bare-bones R implementation of the No-Underrun Sampler
77 (Nawaf Bou-Rabee, Bob Carpenter, Sifan Liu, Stefan Oberdörster. 2025.)
88 written in base R. This implementation attempts to stick very closely
99- to the algorithm described in Appendix A of the paper.
99+ to the algorithm described in Section 2 and Appendix A of the paper.
1010License: MIT + file LICENSE
1111Suggests:
1212 matrixStats
+2-2
R/NURS.R
···4545 # hit
4646 z <- rnorm(d)
4747 rho <- z / sqrt(sum(z^2))
4848+ # https://artowen.su.domains/mc/Ch-randvectors.pdf (pg. 24)
48494950 # run
5051 s <- runif(1, -h / 2, h / 2)
···5556 )
5657 theta + s * rho else theta
57585858- # helpers
5959 log_eps_h <- log(epsilon) + log(h)
6060 orbit_points <- list(theta0)
6161 log_vals <- logpdf(theta0)
62626363- # bookkeeping to get ends
6363+ # bookkeeping to get orbit ends
6464 left <- right <- 1
65656666 # Orbit selection procedure
+9-1
README.Rmd
···1818<!-- badges: start -->
1919<!-- badges: end -->
20202121-Base R implementation of the No-Underrun Sampler.
2121+A Base R, simple implementation of the No-Underrun Sampler. This implementation aims to mostly directly implement the algorithm as described by the paper, with at most small changes for code aesthetics and performance.
22222323## Installation
2424···5454 geom_point(alpha = 0.3) +
5555 theme_minimal()
5656```
5757+5858+## References
5959+6060+* Nawaf Bou-Rabee, Bob Carpenter, Sifan Liu, Stefan Oberdörster. 2025.
6161+[The No-Underrun Sampler: A locally adaptive, gradient free, MCMC
6262+method](https://arxiv.org/abs/2501.18548v2). *arXiv* 2501.18548 v2.
6363+6464+* Art B. Owen. 2013. [Monte Carlo theory, methods and examples](https://artowen.su.domains/mc/). *artowen.su.domains*.
+13-1
README.md
···7788<!-- badges: end -->
991010-Base R implementation of the No-Underrun Sampler.
1010+A Base R, simple implementation of the No-Underrun Sampler. This
1111+implementation aims to mostly directly implement the algorithm as
1212+described by the paper, with at most small changes for code aesthetics
1313+and performance.
11141215## Installation
1316···4649```
47504851<img src="man/figures/README-funnel-1.png" width="100%" />
5252+5353+## References
5454+5555+- Nawaf Bou-Rabee, Bob Carpenter, Sifan Liu, Stefan Oberdörster. 2025.
5656+ [The No-Underrun Sampler: A locally adaptive, gradient free, MCMC
5757+ method](https://arxiv.org/abs/2501.18548v2). *arXiv* 2501.18548 v2.
5858+5959+- Art B. Owen. 2013. [Monte Carlo theory, methods and
6060+ examples](https://artowen.su.domains/mc/). *artowen.su.domains*.