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Charles Margossian

@charlesm993.bsky.social
294 followers 112 following 56 posts

Prof at the University of British Columbia. Research in statistics, ML, and AI for science. Views are my own. charlesm93.github.io.

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Reposted by Charles Margossian
Aki Vehtari @avehtari.bsky.social · 08/09/2026
I'm looking for doctoral students, postdocs and research fellows to work with on Bayesian Workflow. Flexible starting time
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Reposted by Charles Margossian
Richard McElreath 🐈‍⬛ @rmcelreath.bsky.social · 25/08/2026
Someone emailed me to ask if my lectures are online anywhere, so yes here is the link to most recent lectures. These lectures are free and free of Cyclospora
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Reposted by Charles Margossian
Aki Vehtari @avehtari.bsky.social · 21/08/2026
Given all the discussions about Laplace and Jacobians at StanCon, reminder also about my case study with simple visual illustrations users.aalto.fi/~ave/casestu...
users.aalto.fi
Laplace method and Jacobian of parameter transformation – Aki Vehtari
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Charles Margossian @charlesm993.bsky.social · 21/08/2026
As of v2.39, Stan (@mc-stan.org) provides an embedded Laplace approximation for fitting latent Gaussian models. Thanks to the tremendous effort by Steve Bronder, @avehtari.bsky.social, @brianward.dev, and many others. 📽️ www.youtube.com/watch?v=DDTP... 🧵 1/
youtube.com
Charles Margossian - Embedded Laplace Approximation in Stan. StanCon 2026
YouTube video by Stan
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Reposted by Charles Margossian
MC Stan @mc-stan.org · 20/08/2026
StanCon 2026 conference part is over and all the talks are available at StanCon 2026 playlist!
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Reposted by Charles Margossian
Aki Vehtari @avehtari.bsky.social · 20/08/2026
StanCon 2026 has been awesome! The talks are online, but it's been great to also have many discussions in person!
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Charles Margossian @charlesm993.bsky.social · 16/08/2026
✈️ Heading to StanCon'26! 🤝 Looking forward to connecting with colleagues, old and new. 🎙️ I'll give a talk Stan's new embedded Laplace approximation (mc-stan.org/docs/referen...), 📈 and a poster on an analysis of data from multiple clinical trials in Stan (arxiv.org/abs/2603.11019)
arxiv.org
Don't Disregard the Data for Lack of a Likelihood: Bayesian Synthetic Likelihood for Enhanced Multilevel Network Meta-Regression
Multilevel network meta-regression (ML-NMR) enables population-adjusted indirect treatment comparisons by combining individual patient data (IPD) with aggregate data. When individual-level covariates ...
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Reposted by Charles Margossian
Aki Vehtari @avehtari.bsky.social · 13/08/2026
All four books I've co-authored are freely available online for non-commercial use: - Bayesian Workflow at avehtari.github.io/Bayesian-Wor... Links to other three books are in the quoted post 👇 (too many books to fit in one post!)
avehtari.github.io
Bayesian Workflow book: Website – Bayesian Workflow book
Website for the Bayesian Workflow book by Gelman, Vehtari, McElreath, et al. — case studies, code, and exercises in R and Stan.
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Charles Margossian @charlesm993.bsky.social · 10/08/2026
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Reposted by Charles Margossian
Aki Vehtari @avehtari.bsky.social · 14/07/2026
Finally, got a copy of Bayesian workflow book in my hand, and it looks awesome! I really like we did get full colors for figures, too
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Charles Margossian @charlesm993.bsky.social · 14/07/2026
This looks like a great opportunity. I think most people know what an outstanding stats department U Toronto has and on the basis of a visit, I can also attest to how congenial the researchers there are.
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Reposted by Charles Margossian
Vianey Leos Barajas @vianeylb.bsky.social · 14/07/2026
My statistical sciences dept is hiring in the area of Statistical Learning Theory & adjacent fields (assistant professor rank). Located at downtown campus. 🔹Salary Range: $140,000-$190,000 annually (based on experience) 🔹Application Deadline: November 9, 2026 academicjobsonline.org/ajo/jobs/32307
academicjobsonline.org
University of Toronto, Statistical Sciences
Job #AJO32307, Assistant Professor, Statistical Learning Theory, Statistical Sciences, University of Toronto, Toronto, Ontario, CA
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Charles Margossian @charlesm993.bsky.social · 03/07/2026
Catching up with a few co-authors of "Bayesian Workflow" and fellow Stan developers at #ISBA2026. @paulbuerkner.com @vianeylb.bsky.social @yulingy.bsky.social
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Charles Margossian @charlesm993.bsky.social · 28/06/2026
🇯🇵 This week, I'm at the ISBA world meeting in Nagoya, Japan. 🤝 Looking forward to connecting with colleagues, old and new! 🎙️ I'll talk about MCMC on GPUs at the session on "Principled Tuning of MCMC" this Friday at 9am. 🪑 I'll chair the session on "Advances in Sampling" Friday at 11am.
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Charles Margossian @charlesm993.bsky.social · 26/06/2026
📘 With the release of our textbook "Bayesian Workflow" (avehtari.github.io/Bayesian-Wor...), I figured I'd also share the content of my graduate course on the topic at UBC. 🌎 charlesm93.github.io/stat547/ The course contains overlapping and complementary material, homeworks and reading.
avehtari.github.io
Bayesian Workflow book: Website – Bayesian Workflow book
Website for the Bayesian Workflow book by Gelman, Vehtari, McElreath, et al. — case studies, code, and exercises in R and Stan.
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Reposted by Charles Margossian
Aki Vehtari @avehtari.bsky.social · 26/06/2026
posterior R package has now JOSS paper you can cite, too joss.theoj.org/papers/10.21... with @paulbuerkner.com , Jonah Gabry, @mjskay.com
joss.theoj.org
posterior: Tools for Working with Posterior Distributions in R
Bürkner et al., (2026). posterior: Tools for Working with Posterior Distributions in R. Journal of Open Source Software, 11(122), 10526, https://doi.org/10.21105/joss.10526
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Reposted by Charles Margossian
Aki Vehtari @avehtari.bsky.social · 20/05/2026
Stan embedded Laplace was a long project and happy that it's finally released. We are not competing with INLA and TMB software, as they are orders of magnitude faster and scale better with data size for models that you can implement with them 1/
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Reposted by Charles Margossian
Simons Foundation @simonsfoundation.org · 07/03/2026
#FlatironCCM's Teresa Huang explores how symmetries and structure can reveal new insights into the universe, aiding discovery in everything from cosmology to the development of fusion energy. www.simonsfoundation.org/teresa-hua…
simonsfoundation.org
Teresa Huang: Bridging Science and Machine Learning at Cosmic Scales
Flatiron Institute Research Fellow Teresa Huang uses machine learning to help scientists improve models for scientific applications involving large datasets.
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Reposted by Charles Margossian
Sam Power @spmontecarlo.bsky.social · 05/03/2026
do mine eyes deceive me? a release date in the present year?
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Charles Margossian @charlesm993.bsky.social · 29/01/2026
StanCon 2026 is this August 17-21 in Upsala, Sweden 🇸🇪 www.stancon2026.org ⏰ Abstracts for contributed talks are due Feb 25 ⏰ Abstracts for posters are due May 27 And just to be clear: Yes, StanCon is my favorite conference to attend!! Can't wait for this one!
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Reposted by Charles Margossian
Aki Vehtari @avehtari.bsky.social · 26/01/2026
Bayesian Workflow by Andrew Gelman, Aki Vehtari, @rmcelreath.bsky.social with @danpsimpson.bsky.social, @charlesm993.bsky.social, @yulingy.bsky.social, Lauren Kennedy, Jonah Gabry, @paulbuerkner.com, @modrakm.bsky.social, @vianeylb.bsky.social (in production, estimated copy-editing time 6 weeks)
**Part 1: From Bayesian inference to Bayesian workflow**

1. Bayesian theory and Bayesian practice
2. Statistical modeling and workflow
3. Computational tools
4. Introduction to workflow: Modeling performance on a multiple choice exam

**Part 2: Statistical workflow**

5. Building statistical models
6. Using simulations to capture uncertainty
7. Prediction, generalization, and causal inference
8. Visualizing and checking fitted models
9. Comparing and improving models
10. Statistical inference and scientific inference

**Part 3: Computational workflow**

11. Fitting statistical models
12. Diagnosing and fixing problems with fitting
13. Approximate algorithms and approximate models
14. Simulation-based calibration checking
15. Statistical modeling as software development
**4. Case studies**

16. Coding a series of models: Simulated data of movie ratings
17. Prior specification for regression models: Reanalysis of a sleep study
18. Predictive model checking and comparison: Clinical trial
19. Building up to a hierarchical model: Coronavirus testing
20. Using a fitted model for decision analysis: Mixture model for time series competition
21. Posterior predictive checking: Stochastic learning in dogs
22. Incremental development and testing: Black cat adoptions
23. Debugging a model: World Cup football
24. Leave-one-out cross validation model checking and comparison: Roaches
25. Model building and expansion: Golf putting
26. Model building with latent variables: Markov models for animal movement
27. Model building: Time-series decomposition for birthdays
28. Models for regression coefficients and variable selection: Student grades
29. Sampling problems with latent variables: No vehicles in the park
30. Challenge of multimodality: Differential equation for planetary motion
31. Simulation-based calibration checking in model development workflow

**Appendices**

A. Statistical and computational workflow for Bayesians and non-Bayesians
B. How to get the most out of Bayesian Data Analysis
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Reposted by Charles Margossian
Simons Foundation @simonsfoundation.org · 08/01/2026
Simons Foundation president David Spergel recently spoke to @issuesinst.bsky.social about the future of science philanthropy: issues.org/american-science-simons-… #science #math #philanthropy
issues.org
“There Are Two Possible Futures for American Science.”
The Simons Foundation president talks about science philanthropy, the future of the research enterprise, and remaining hopeful.
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Charles Margossian @charlesm993.bsky.social · 08/01/2026
What is "workflow" and why is it important? The latest blog post by Andrew Gelman: statmodeling.stat.columbia.edu/2026/01/08/w...
statmodeling.stat.columbia.edu
What is “workflow” and why is it important? | Statistical Modeling, Causal Inference, and Social Science
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Charles Margossian @charlesm993.bsky.social · 14/12/2025
🇪🇸 This week I'm attending ICSDS (International Conference on Stats & Data Science) in Sevilla, Spain. 🤝 Looking forward to connecting with colleagues, old and new! 💡On Wednesday, I'll give a talk on "Variational Inference in the Presence of Symmetry" at the 9 am session on Bayesian learning.
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Reposted by Charles Margossian
Diana Cai @dianarycai.bsky.social · 04/12/2025
Check out my poster today (Thurs) at 11am--2pm session. Exhibit Hall C,D,E Poster Location: #602 "Fisher meets Feynman: score-based variational inference with a product of experts" (NeurIPS spotlight) with Robert Gower, David Blei, and Lawrence Saul @flatironinstitute.org #NeurIPS2025
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Charles Margossian @charlesm993.bsky.social · 07/11/2025
Applications for the PhD and MSc programs in statistics at UBC are now open! 📆 Deadline for PhD program is December 1st 📆 Deadline for MSc program is January 5th The department covers all areas of statistics and we have a lot of momentum in Bayesian computation!
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Charles Margossian @charlesm993.bsky.social · 17/09/2025
Application for a postdoc research fellowship in computational mathematics at the Flatiron Institute in New York are now open! apply.interfolio.com/173401 📆 Deadline is December 1st. 🔭 This is an excellent place to do research at the interface of ML, stats and the natural sciences.
apply.interfolio.com
Apply - Interfolio {{$ctrl.$state.data.pageTitle}} - Apply - Interfolio
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Charles Margossian @charlesm993.bsky.social · 10/09/2025
My paper with Loucas Pillaud-Vivien and Lawrence Saul, “Variational Inference for Uncertainty Quantification: An Analysis of Trade-offs”, has been accepted for publication in the Journal of Machine Learning Research. 📃 arxiv.org/abs/2403.13748 🧵 1/
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Charles Margossian @charlesm993.bsky.social · 04/09/2025
Stan v2.37 has been released! blog.mc-stan.org/2025/09/02/r...
blog.mc-stan.org
Release of CmdStan 2.37
We are very happy to announce that the 2.37.0 release of CmdStan is now available on Github! As usual, the release of CmdStan is accompanied by new releases of Stan Math, core Stan, and Stanc3. Thi…
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Charles Margossian @charlesm993.bsky.social · 01/08/2025
Yes, in principle, I start at UBC Statistics today. But right now, I'm running around the Frankfurt airport to catch my flight to Vancouver .... 🏃‍♂️🧳✈️ www.stat.ubc.ca/news/charles...
stat.ubc.ca
Charles Margossian Joins the UBC Department of Statistics | UBC Statistics
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Charles Margossian @charlesm993.bsky.social · 28/07/2025
Earlier this month, I taught at the summer school on "cryptography, statistics and machine learning" (mathschool.ysu.am) hosted by Yerevan State University in Armenia 🇦🇲 🙏 Thank you to the organizers for putting together such a wonderful event! I truly enjoyed interacting with the students.
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Charles Margossian @charlesm993.bsky.social · 26/06/2025
New manuscript by Nawaf Bou-Rabee, Bob Carpenter, Tore Kleppe and Sifan Liu on the WALNUTS algorithm which improves of the NUTS sampler by introducing a locally adaptive step size. 📜 Paper: arxiv.org/pdf/2506.18746 💻 Code: github.com/bob-carpente...
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Charles Margossian @charlesm993.bsky.social · 15/06/2025
🇸🇬 Next stop: Singapore for BayesComp'25 (bayescomp2025.sg) The organizers put together a wonderful program! I'll be: 🪑 chairing the session on "Parallel comp for MCMC" 🎙️ speaking at the session on "Advances in VI" Looking forward to meeting researchers and catching up with colleagues.
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Charles Margossian @charlesm993.bsky.social · 13/06/2025
Research opportunity for a graduate student in ecology 🌳 at UBC 🇨🇦 with Lizzie Wolkovich and the Temporal Ecology lab (temporalecology.org). 📝 Apply here: temporalecology.org/joining-the-... by July 1st 2025! The abstract sounds fascinating (see attached).
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Charles Margossian @charlesm993.bsky.social · 09/06/2025
🧑‍💻 Candidate release for Stan 2.37 is out: discourse.mc-stan.org/t/cmdstan-st.... Lots of exciting features to try out, including: - embedded/integrated Laplace approximation - new constrained types (e.g. sum_to_zero_matrix) - built-in constraint transformations exposed
discourse.mc-stan.org
CmdStan & Stan 2.37 release candidate
I am happy to announce that the latest release candidates of CmdStan and Stan are now available on Github! This release cycle brings the embedded Laplace approximation, a sum-to-zero matrix type, new...
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Reposted by Charles Margossian
Andrew Gelman et al. @statmodeling.bsky.social · 27/05/2025
Taking our Models Seriously (my talk at StanBio Connect, this Friday 9am) statmodeling.stat.columbia.edu/2025/05/27/t...
statmodeling.stat.columbia.edu
Taking our Models Seriously (my talk at StanBio Connect, this Friday 9am) | Statistical Modeling, Causal Inference, and Social Science
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Charles Margossian @charlesm993.bsky.social · 05/05/2025
✨ Thank you #AISTATS for the best paper award!! 📜 arxiv.org/abs/2410.11067 💡What does VI learn and under what conditions? The answer lies in symmetry. 🤝 Honored to share this award with my co-author Lawrence Saul from @flatironinstitute.org
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Charles Margossian @charlesm993.bsky.social · 01/05/2025
🇹🇭 Just arrived in Phuket, Thailand for #AISTATS 2025. 📃 I'll presenting my recent work with Lawrence Saul on Variational Inference in Location-Sacale Families: arxiv.org/abs/2410.11067 DM if you are in town and want to connect at the conference!
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Reposted by Charles Margossian
Kamélia Daudel @kdau.bsky.social · 28/04/2025
For the first time, Journal-to-Conference papers have entered the schedule of #AISTATS2025 🎉 To celebrate here is a bingo card: should you be among the first to meet all of our amazing Journal-to-Conference presenters (I need proof!), I’ll buy you a drink... provided that you can find me too!
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Charles Margossian @charlesm993.bsky.social · 21/04/2025
📚 Putting together a reading list for #AISTATS 2025. I already found a few very good papers, and I'm curious to hear about more accepted publications.
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Charles Margossian @charlesm993.bsky.social · 16/04/2025
📣 Nominations for the Stan Governing Body are open for another two weeks. Calling on all members of the Stan community to consider this role. 🔗 discourse.mc-stan.org/t/elections-... 💡 A post about my own experience: statmodeling.stat.columbia.edu/2025/03/15/e...
discourse.mc-stan.org
Elections for Stan Governing Body 2025
It’s this time of the year again! (And in fact, we’re a little bit overdue.) We’re renewing the Stan Governing Body (SGB) with all 5 seats up for grabs. Current SGB members may still run, however the...
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Charles Margossian @charlesm993.bsky.social · 20/03/2025
I'm thrilled to share that, starting this summer, I will continue my academic journey as an assistant professor of statistics at the University of British Columbia in Vancouver, Canada. Full statement here: charlesm93.github.io/files/letter...
charlesm93.github.io
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Julyan Arbel @julyanarbel.bsky.social · 17/03/2025
🚀 Exciting news! We're proposing a new *Bayesian Deep Learning* section within @isba-bayesian.bsky.social . If you support this initiative, add your name to the petition and help make it happen! 🔗 Petition: tinyurl.com/527vaamz Sinead Williamson, Theo Papamarkou @vincefort.bsky.social Sara Wade 1/2
tinyurl.com
Petition to form a Bayesian Deep Learning section at ISBA
Petition to form a Bayesian Deep Learning section at ISBA We, the undersigned members of the International Society for Bayesian Analysis (ISBA), petition the ISBA board to establish a new Bayesian D...
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Charles Margossian @charlesm993.bsky.social · 14/03/2025
📣 Calling all members of the Stan community to action! ❕We're renewing the Stan Governing Body. This is a fantastic way to contribute to the project. The SGB co-organizes StanCon and related events, funds developers, and helps set the directions of the project. 🧵 Link in thread.
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Charles Margossian @charlesm993.bsky.social · 13/03/2025
StanConnects are a series of one-day online conferences for the application of Stan to specific areas. This year, we're kicking off with Stan for biology (broadly defined), co-organized by @ericnovik.bsky.social and @vianeylb.bsky.social, on 30 May '25!! stanbio.org
stanbio.org
StanBio Connect 2025 – StanBio Connect
Advancing Biomedical Research with Stan
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Charles Margossian @charlesm993.bsky.social · 13/02/2025
Yesterday, an undergraduate asked me whether I used the same tools as 3blue1brown to animate my slides. Maybe one of the coolest compliments I've ever gotten :) ... and excellent reason to share my appreciation for this beautiful channel: www.youtube.com/@3blue1brown.
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Charles Margossian @charlesm993.bsky.social · 13/02/2025
@flatironinstitute.org released recordings of the FWAM meeting, a 2-day event during which experts present introductory talks on computational and scientific methods. www.simonsfoundation.org/event/2024-f... I had the pleasure to give a talk on: "For how many iterations should we run MCMC?"
simonsfoundation.org
2024 Flatiron Wide Autumn Meeting (FWAM)
2024 Flatiron Wide Autumn Meeting (FWAM) on Simons Foundation
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Reposted by Charles Margossian
Diana Cai @dianarycai.bsky.social · 24/01/2025
Our paper "Batch, match, and patch: low-rank approximations for score-based variational inference" is accepted to #AISTATS2025. This paper addresses score-based variational inference with Gaussians (batch and match VI) with low rank + diagonal covariances. Preprint: arxiv.org/abs/2410.22292
arxiv.org
Batch, match, and patch: low-rank approximations for score-based variational inference
Black-box variational inference (BBVI) scales poorly to high dimensional problems when it is used to estimate a multivariate Gaussian approximation with a full covariance matrix. In this paper, we ext...
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Charles Margossian @charlesm993.bsky.social · 22/01/2025
Our paper was accepted (oral) for #AISTATS. From the AC: "This paper provides a very elegant analysis of variational inference in location-scale families, providing much-needed insights into when and why variational methods can so often accurately obtain accurate means estimates."
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Charles Margossian @charlesm993.bsky.social · 12/01/2025
Kicking off the year with a visit to the Center for AI Fundamentals at the University of Manchester 🇬🇧 Thank you for the invitation and the opportunity to exchange ideas!
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