Neals funnel - #334
Neals funnel#334michalkamin wants to merge 20 commits into
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non-centered
| "name": "neals_funnel", | ||
| "keywords": ["synthetic", "funnel"], | ||
| "title": "Neal's Funnel", | ||
| "description": "Neal's Funnel is a classic example of a hierarchical model that is difficult to sample from due to its geometry. It consists of a two-dimensional distribution where one dimension has a standard normal distribution and the other dimension has a normal distribution whose variance depends on the first dimension. This creates a 'funnel' shape that can be challenging for MCMC algorithms to explore effectively.", |
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Maybe add info that the data is just the dimension?
| "title": "Neal's Funnel (Centered Parameterization)", | ||
| "added_by": "Michal Kaminski", | ||
| "added_date": "2026-09-24", | ||
| "description": "Neal's Funnel is a classic example of a hierarchical model that is difficult to sample from due to its geometry.", |
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Maybe add that its the centered parametrisation and what that mean?
| Centered Neal's Funnel for PosteriorDB | ||
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| D = data.get("D", 9) |
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Shouldnt this be read in from the data?
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changed to D = int(data["D"]) so there is no silent fallback and yields KeyError
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LGTM @JTorgander do you want to just take a look at this also? |
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I actually had to change the JSON structure in the model info. The DATABASE_CONTENT.md specifies that it should have a "model_code" field, but when I try to load it in R using posterior() function it gives an error. I see now that other models have the code pointer as "model_implementations", and then inside a "model_code" field for respective languages. Maybe I misinterpreted the documentation; I just wanted to bring that up. @MansMeg |
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Excellent. Its most likely a bug/bad documentation. Please submit this as an issue that I can handle later on |
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LGTM as well! |
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Please make this a proper pr so we can merge to development |
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TLDR: Add the non-centered and centered parameterization of the Neal's funnel model.
This draft PR introduces the Neal's Funnel model to PosteriorDB using a 9-dimensional centered and non-centered parameterization. Neal's Funnel is a classic synthetic distribution that provides a challenging geometry for benchmarking MCMC samplers
Changes included