# General

**URL:** https://discourse.mc-stan.org/c/general/24.md?page=2

[Latest](https://discourse.mc-stan.org/latest.md) · [Categories](https://discourse.mc-stan.org/categories.md) · [Tags](https://discourse.mc-stan.org/tags.md)

**Page:** 3

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## [Convergence issues with multivariate model in brms](https://discourse.mc-stan.org/t/convergence-issues-with-multivariate-model-in-brms/40835)

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**Author:** [@sofia-pereira](https://discourse.mc-stan.org/u/sofia-pereira)\
**Replies:** 2\
**Last updated:** [January 20, 2026, 10:26am UTC](https://discourse.mc-stan.org/t/convergence-issues-with-multivariate-model-in-brms/40835 "2026-01-20T10:26:28Z")

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Hello, I am new to modelling and attempting my first multivariate model in brms. I am modelling three different covarying DVs as a function of two shared predictors, though an important feature of this model is that my …

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## [Hierarchical model to aggregate summary statistics and estimate a product of proportions ($P1 \\times P2$)](https://discourse.mc-stan.org/t/hierarchical-model-to-aggregate-summary-statistics-and-estimate-a-product-of-proportions-p1-times-p2/40798)

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**Author:** [@arc\_circle\_square](https://discourse.mc-stan.org/u/arc_circle_square)\
**Replies:** 1\
**Last updated:** [January 9, 2026, 10:12pm UTC](https://discourse.mc-stan.org/t/hierarchical-model-to-aggregate-summary-statistics-and-estimate-a-product-of-proportions-p1-times-p2/40798 "2026-01-09T22:12:37Z")

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I am trying to estimate the proportion of U.S. adults who use chatbots as a “friend.” (That’s not the exact RQ but it’s a good enough stand-in!) I am estimating this as a product of two probabilities: P = P1 \\times P2. …

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## [CmdStan & Stan 2.38 Release Candidates](https://discourse.mc-stan.org/t/cmdstan-stan-2-38-release-candidates/40790)

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**Author:** [@WardBrian](https://discourse.mc-stan.org/u/WardBrian)\
**Replies:** 2\
**Last updated:** [January 6, 2026, 7:05pm UTC](https://discourse.mc-stan.org/t/cmdstan-stan-2-38-release-candidates/40790 "2026-01-06T19:05:55Z")

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I am happy to announce that the latest release candidates of CmdStan and Stan are now available on Github! This release cycle focused on stability and usability improvements, with a few new features and a lot of work un…

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## [Technical issues implementing powerscaling procedure on distribution of estimated differences](https://discourse.mc-stan.org/t/technical-issues-implementing-powerscaling-procedure-on-distribution-of-estimated-differences/40768)

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**Author:** [@llewmills](https://discourse.mc-stan.org/u/llewmills)\
**Replies:** 4\
**Last updated:** [January 5, 2026, 9:19pm UTC](https://discourse.mc-stan.org/t/technical-issues-implementing-powerscaling-procedure-on-distribution-of-estimated-differences/40768 "2026-01-05T21:19:46Z")

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I am having trouble implementing the procedure for powerscaling research quantities of interest outlined in Chapter 14 of @avehtari’s notebook outlining a procedure for comparing models with different outcomes. The mode…

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## [Advice on Bayes factor analysis (logml could not be estimated within maxiter)](https://discourse.mc-stan.org/t/advice-on-bayes-factor-analysis-logml-could-not-be-estimated-within-maxiter/40761)

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**Author:** [@mawilson1234](https://discourse.mc-stan.org/u/mawilson1234)\
**Replies:** 2\
**Last updated:** [December 30, 2025, 6:18am UTC](https://discourse.mc-stan.org/t/advice-on-bayes-factor-analysis-logml-could-not-be-estimated-within-maxiter/40761 "2025-12-30T06:18:26Z")

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I’m running into issues doing a Bayes factor analysis on a dataset I’ve gathered. The model I’m fitting is a pretty simple logistic regression: correct ~ voice\_n + (1 + voice\_n | subject) + (1 | item:voice\_n) …

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## [How to choose matrices in an univariate dynamic probit model for online inference (Assumed Density Filter)](https://discourse.mc-stan.org/t/how-to-choose-matrices-in-an-univariate-dynamic-probit-model-for-online-inference-assumed-density-filter/40748)

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**Author:** [@fexymine](https://discourse.mc-stan.org/u/fexymine)\
**Replies:** 4\
**Last updated:** [December 19, 2025, 8:24pm UTC](https://discourse.mc-stan.org/t/how-to-choose-matrices-in-an-univariate-dynamic-probit-model-for-online-inference-assumed-density-filter/40748 "2025-12-19T20:24:02Z")

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Goodmorning everyone, I’m working with a specific state space model (Non Linear Non Gaussian) which is the univariate probit model (one binary observation at each time with a Gaussian latent process. \\theta\_t = G\\thet…

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## [ONNX Support for Stan](https://discourse.mc-stan.org/t/onnx-support-for-stan/40706)

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**Author:** [@bparbhu](https://discourse.mc-stan.org/u/bparbhu)\
**Replies:** 4\
**Last updated:** [December 10, 2025, 3:09pm UTC](https://discourse.mc-stan.org/t/onnx-support-for-stan/40706 "2025-12-10T15:09:08Z")

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Hey all, Today myself, Andreas Fehlner, and Adam Pocock made a presentation to the ONNX steering committee to propose new working groups around ONNX support for Bayesian Models from various frameworks. The working group…

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## [Multilevel Logit Models with Small Level-2 Sample Size](https://discourse.mc-stan.org/t/multilevel-logit-models-with-small-level-2-sample-size/40632)

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**Author:** [@junxu2018](https://discourse.mc-stan.org/u/junxu2018)\
**Replies:** 6\
**Last updated:** [December 10, 2025, 12:09am UTC](https://discourse.mc-stan.org/t/multilevel-logit-models-with-small-level-2-sample-size/40632 "2025-12-10T00:09:02Z")

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Dear all, I ran this multilevel logit model using rstanarm with 10 groups at level-2. My focal variable is gender (male). The thing that puzzles me is that the overall/grand effect (by looking at the 95% credible interv…

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## [New 2025/2026 event for Bayesian Data Analysis Meetup](https://discourse.mc-stan.org/t/new-2025-2026-event-for-bayesian-data-analysis-meetup/40721)

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**Author:** [@bparbhu](https://discourse.mc-stan.org/u/bparbhu)\
**Replies:** 0\
**Last updated:** [December 9, 2025, 3:26pm UTC](https://discourse.mc-stan.org/t/new-2025-2026-event-for-bayesian-data-analysis-meetup/40721 "2025-12-09T15:26:58Z")

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Hey all, I hope all is well with everyone and as we round out the year something I’ve been talking about more lately is how do we deploy and get Bayesian models into production. Depending on the framework what are the …

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## [Rtools repeated installation problem](https://discourse.mc-stan.org/t/rtools-repeated-installation-problem/40707)

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**Author:** [@wenyanbin4](https://discourse.mc-stan.org/u/wenyanbin4)\
**Replies:** 0\
**Last updated:** [December 4, 2025, 3:44am UTC](https://discourse.mc-stan.org/t/rtools-repeated-installation-problem/40707 "2025-12-04T03:44:47Z")

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The current version of R is 4.5.2. When using the brms package, rtools44 is repeatedly installed. You should manually download rtools45 from the official website to resolve this issue.

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## [Matrix -\> array conversion functions](https://discourse.mc-stan.org/t/matrix-array-conversion-functions/40703)

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**Author:** [@huffyhenry](https://discourse.mc-stan.org/u/huffyhenry)\
**Replies:** 1\
**Last updated:** [December 3, 2025, 4:58pm UTC](https://discourse.mc-stan.org/t/matrix-array-conversion-functions/40703 "2025-12-03T16:58:25Z")

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When working with multivariate data I like representing it as a matrix rather than array\[\] vector. This enables linear transformations to be expressed as large matrix multiplications. But when calculating the likelihood,…

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## [RStan performance differences](https://discourse.mc-stan.org/t/rstan-performance-differences/40684)

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**Author:** [@AEman](https://discourse.mc-stan.org/u/AEman)\
**Replies:** 1\
**Last updated:** [December 1, 2025, 11:34am UTC](https://discourse.mc-stan.org/t/rstan-performance-differences/40684 "2025-12-01T11:34:06Z")

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I am switching from one linux HPC system to another. I have noticed a big difference in performance with similar hardware. I was wondering whether it has something to do with compiler flags, could you let me know if it s…

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## [Summary(brmfit) of any fits from brm() gives me errors, but I can still access the fit by just typing fit object](https://discourse.mc-stan.org/t/summary-brmfit-of-any-fits-from-brm-gives-me-errors-but-i-can-still-access-the-fit-by-just-typing-fit-object/40690)

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**Author:** [@Ikuyasu](https://discourse.mc-stan.org/u/Ikuyasu)\
**Replies:** 1\
**Last updated:** [December 1, 2025, 4:19am UTC](https://discourse.mc-stan.org/t/summary-brmfit-of-any-fits-from-brm-gives-me-errors-but-i-can-still-access-the-fit-by-just-typing-fit-object/40690 "2025-12-01T04:19:19Z")

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summary(brmfit) of any fits from brm() gives me errors, but I can still access the fit by just typing fit object. Is it normal? It happens to any toy examples. I think there is something wrong with the C++ compiling, bu…

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## [Abysmal performance on a new AMD laptop with windows 11](https://discourse.mc-stan.org/t/abysmal-performance-on-a-new-amd-laptop-with-windows-11/40642)

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**Author:** [@zacho](https://discourse.mc-stan.org/u/zacho)\
**Replies:** 11\
**Last updated:** [November 25, 2025, 8:29pm UTC](https://discourse.mc-stan.org/t/abysmal-performance-on-a-new-amd-laptop-with-windows-11/40642 "2025-11-25T20:29:41Z")

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Good day all, I need help with speeding up my hardware, which is inexcusably slow. I suspect it’s my OS or some aspect of the setup. I have a new laptop through my university running (unfortunately) Windows 11. The CPU…

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## [Setting an intercept prior on a regression in brms](https://discourse.mc-stan.org/t/setting-an-intercept-prior-on-a-regression-in-brms/40657)

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**Author:** [@kholsinger](https://discourse.mc-stan.org/u/kholsinger)\
**Replies:** 2\
**Last updated:** [November 19, 2025, 3:54pm UTC](https://discourse.mc-stan.org/t/setting-an-intercept-prior-on-a-regression-in-brms/40657 "2025-11-19T15:54:16Z")

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I have what is probably a very simple problem, but I haven’t found the solution for it yet, and I’d appreciate some help. I’m setting a prior on an intercept, which gives me a summary() that confuses me. Here’s a very si…

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## [Predictions from univariate models differ from those of a single multivariate model](https://discourse.mc-stan.org/t/predictions-from-univariate-models-differ-from-those-of-a-single-multivariate-model/40655)

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**Author:** [@llewmills](https://discourse.mc-stan.org/u/llewmills)\
**Replies:** 1\
**Last updated:** [November 19, 2025, 10:58am UTC](https://discourse.mc-stan.org/t/predictions-from-univariate-models-differ-from-those-of-a-single-multivariate-model/40655 "2025-11-19T10:58:54Z")

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I am conducting a multivariate ordinal regression examining the effect of number of days of amphetamine-type-stimulant use in the 28 days prior to starting treatment (variable ats\_baseline ) on three outcomes: psychologi…

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## [In hypothesis(brmsfit,'Var \> 0') output what is the signification of the \*, \*+, \*\*, or \*\*\*](https://discourse.mc-stan.org/t/in-hypothesis-brmsfit-var-0-output-what-is-the-signification-of-the-or/40652)

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**Author:** [@sboylan](https://discourse.mc-stan.org/u/sboylan)\
**Replies:** 2\
**Last updated:** [November 19, 2025, 9:35am UTC](https://discourse.mc-stan.org/t/in-hypothesis-brmsfit-var-0-output-what-is-the-signification-of-the-or/40652 "2025-11-19T09:35:58Z")

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Hello folks, I am trying to understand what the Stars in the output of hypothesis() represent. As far as I understand, it is a threshold on the evidence ratio. If ER\>3 we have \* Then I struggle to find some explanati…

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## ['priorsense' package plotting issue](https://discourse.mc-stan.org/t/priorsense-package-plotting-issue/39829)

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**Author:** [@buf](https://discourse.mc-stan.org/u/buf)\
**Replies:** 10\
**Last updated:** [November 11, 2025, 11:35am UTC](https://discourse.mc-stan.org/t/priorsense-package-plotting-issue/39829 "2025-11-11T11:35:00Z")

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Hi, I came across the ‘priorsense’ package and wanted to try it out. Unfortunately, I can’t make any of the plotting functions work. My stan object is called ‘fit’ and contains ‘lprior’ and ‘log\_lik’ values calculated i…

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## [Participation Needed: Probabilistic Programming Study](https://discourse.mc-stan.org/t/participation-needed-probabilistic-programming-study/38842)

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**Author:** [@nattube](https://discourse.mc-stan.org/u/nattube)\
**Replies:** 15\
**Last updated:** [November 11, 2025, 9:44am UTC](https://discourse.mc-stan.org/t/participation-needed-probabilistic-programming-study/38842 "2025-11-11T09:44:53Z")

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Hello everyone, we are currently conducting a study on Bayesian inference debugging and would like to invite you to participate in our study. It would be greatly appreciated and could help to further knowledge in the a…

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## [C++ textbook and blog recommendations](https://discourse.mc-stan.org/t/c-textbook-and-blog-recommendations/11990)

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**Author:** [@anon79882417](https://discourse.mc-stan.org/u/anon79882417)\
**Replies:** 13\
**Last updated:** [November 7, 2025, 6:51am UTC](https://discourse.mc-stan.org/t/c-textbook-and-blog-recommendations/11990 "2025-11-07T06:51:54Z")

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Any one have good C++ textbook or blog post recommendations? Both are great - textbooks are good for an overarching view of the language, or one feature of the language, whereas blogs can give a good periodic dose of ap…

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## [Question in multistate model](https://discourse.mc-stan.org/t/question-in-multistate-model/40625)

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**Author:** [@huangxy](https://discourse.mc-stan.org/u/huangxy)\
**Replies:** 0\
**Last updated:** [November 5, 2025, 6:43am UTC](https://discourse.mc-stan.org/t/question-in-multistate-model/40625 "2025-11-05T06:43:17Z")

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Hi everyone, I’m new here. I’m trying to develop a multistate model using Rstan. However, because my sample size was quite large (over 10million transitions), I need to use HPC. Problem occurs that the HPC is not compa…

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## [Optimal compiler flags M4 Max](https://discourse.mc-stan.org/t/optimal-compiler-flags-m4-max/40559)

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**Author:** [@Sean\_Matthews](https://discourse.mc-stan.org/u/Sean_Matthews)\
**Replies:** 2\
**Last updated:** [October 27, 2025, 11:28pm UTC](https://discourse.mc-stan.org/t/optimal-compiler-flags-m4-max/40559 "2025-10-27T23:28:39Z")

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Very simple question (I’ve searched, but I can’t find a matching answer). I have a Mac M4 Max. How should I set compiler flags (in cmdstanpy) for optimal performance? All advice appreciated.

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## [Long model crashes with exception code "0xc0000005" pointing to .dll file](https://discourse.mc-stan.org/t/long-model-crashes-with-exception-code-0xc0000005-pointing-to-dll-file/40548)

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**Author:** [@FlyingTurtle](https://discourse.mc-stan.org/u/FlyingTurtle)\
**Replies:** 2\
**Last updated:** [October 21, 2025, 3:23am UTC](https://discourse.mc-stan.org/t/long-model-crashes-with-exception-code-0xc0000005-pointing-to-dll-file/40548 "2025-10-21T03:23:50Z")

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Hi, Thank you for reading my first post! Please let me know if you have suggestions on writing a question better. Summary I am running a long brm() single-chain model on a newly-purchased PC (Windows 11). The plan is t…

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## [Extracting predictions for each outcome in multivariate ordinal model](https://discourse.mc-stan.org/t/extracting-predictions-for-each-outcome-in-multivariate-ordinal-model/40474)

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**Author:** [@llewmills](https://discourse.mc-stan.org/u/llewmills)\
**Replies:** 1\
**Last updated:** [October 8, 2025, 3:25pm UTC](https://discourse.mc-stan.org/t/extracting-predictions-for-each-outcome-in-multivariate-ordinal-model/40474 "2025-10-08T15:25:08Z")

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I am trying to extract posterior predictions from a brms multivariate ordinal regression object but I can’t figure out how to extract the predictions for each outcome separately Here is the model bform\_ord\_mvr\_ppq \<- b…

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## [CmdStan & Stan 2.37 release candidate](https://discourse.mc-stan.org/t/cmdstan-stan-2-37-release-candidate/39655)

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**Author:** [@WardBrian](https://discourse.mc-stan.org/u/WardBrian)\
**Replies:** 19\
**Last updated:** [October 7, 2025, 9:34pm UTC](https://discourse.mc-stan.org/t/cmdstan-stan-2-37-release-candidate/39655 "2025-10-07T21:34:51Z")

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Edit (August 18): A this release candidate has been published to address several stability issues. Due to ongoing numeric stability issues with the embedded Laplace approximation, we have decided to leave it in developme…

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## [Should we automatically close topics after some time?](https://discourse.mc-stan.org/t/should-we-automatically-close-topics-after-some-time/40376)

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**Author:** [@martinmodrak](https://discourse.mc-stan.org/u/martinmodrak)\
**Replies:** 8\
**Last updated:** [October 6, 2025, 8:43pm UTC](https://discourse.mc-stan.org/t/should-we-automatically-close-topics-after-some-time/40376 "2025-10-06T20:43:36Z")

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We currently leave topics open for discussion indefinitely. This lets people get back with solutions to old problems (which happens!) or have long slow discussions about a problem for years (which also happens). But it …

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## [Use of antithetic pairs for faster Monte Carlo integration?](https://discourse.mc-stan.org/t/use-of-antithetic-pairs-for-faster-monte-carlo-integration/40422)

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**Author:** [@Joshua\_Wiley](https://discourse.mc-stan.org/u/Joshua_Wiley)\
**Replies:** 2\
**Last updated:** [October 6, 2025, 2:44pm UTC](https://discourse.mc-stan.org/t/use-of-antithetic-pairs-for-faster-monte-carlo-integration/40422 "2025-10-06T14:44:42Z")

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Hi All, This question may be a bit “Stan-adjacent” so feel free to close if not appropriate to ask here. I work with categorical, multilevel data. For example that may be counts (like self-reported or wearable devices e…

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## [Visualizing distributions of covariance matrices](https://discourse.mc-stan.org/t/visualizing-distributions-of-covariance-matrices/40430)

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**Author:** [@spinkney](https://discourse.mc-stan.org/u/spinkney)\
**Replies:** 0\
**Last updated:** [September 27, 2025, 2:16pm UTC](https://discourse.mc-stan.org/t/visualizing-distributions-of-covariance-matrices/40430 "2025-09-27T14:16:17Z")

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This paper was available for preprint for years now but was recently published. It’s a good read to understand why the Stan team began recommending LKJ instead of the Inverse Wishart for correlation/covariance matrix p…

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## [Stan stickers?](https://discourse.mc-stan.org/t/stan-stickers/11385)

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**Author:** [@andrewgelman](https://discourse.mc-stan.org/u/andrewgelman)\
**Replies:** 28\
**Last updated:** [September 26, 2025, 2:21pm UTC](https://discourse.mc-stan.org/t/stan-stickers/11385 "2025-09-26T14:21:45Z")

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Someone just told me he wanted to order a Stan sticker for his laptop, but such stickers are not available on the website, which just has t-shirts and mugs. Does someone know how to make stickers available? Thanks!

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## [Vectorisation of \_cdf functions](https://discourse.mc-stan.org/t/vectorisation-of-cdf-functions/28555)

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**Author:** [@pboesu](https://discourse.mc-stan.org/u/pboesu)\
**Replies:** 4\
**Last updated:** [September 24, 2025, 11:39pm UTC](https://discourse.mc-stan.org/t/vectorisation-of-cdf-functions/28555 "2025-09-24T23:39:49Z")

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When used with non-scalar arguments \_cdf functions appear to return the sum of the elementwise application of the CDF to the inputs. This is (a) not strictly documented and (b) does not make much sense from an applicatio…

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