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Posts by Sam Duffield

You think this could be more efficient or have other benefits over Ziggurat?

22 hours ago 1 0 1 0
Examples - cuthbert This section contains examples of how to use cuthbert on some fun problems, highlighting the flexibility of the library and the utility of the underlying methods.

There's a load of fun examples in the cuthbert docs and we're always looking to add more! 🐛

state-space-models.github.io/cuthbert/exa...

1 week ago 3 0 0 0
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In this highly nonlinear example it's more accurate and faster than both extended and particle filters.

state-space-models.github.io/cuthbert/exa...

1 week ago 3 0 1 0
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Add the Ensemble Kalman Filter by DanWaxman · Pull Request #229 · state-space-models/cuthbert This PR introduces the ensemble Kalman filter (EnKF). The implementation is based in part on the implementation of CD-Dynamax. That implementation, in turn, is inspired by Algorithm 10.2 in the not...

The ensemble Kalman filter is now in cuthbert 🔥

The EnKF is one of those algorithms that "just works" - oftentimes in settings it has no right to

github.com/state-space-...

1 week ago 7 1 1 0
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GitHub - state-space-models/cuthbert: State-space model inference with JAX State-space model inference with JAX. Contribute to state-space-models/cuthbert development by creating an account on GitHub.

github.com/state-space-...

2 months ago 1 0 0 0
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It was my birthday this week, it really had to be done

2 months ago 4 0 2 0
“Parallelizing MCMC Across the Sequence Length”: This one is really cool. | Statistical Modeling, Causal Inference, and Social Science

“Parallelizing MCMC Across the Sequence Length”: This one is really cool.
statmodeling.stat.columbia.edu/2026/02/03/p...

2 months ago 14 3 0 0
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GitHub - state-space-models/cuthbert: State-space model inference with JAX State-space model inference with JAX. Contribute to state-space-models/cuthbert development by creating an account on GitHub.

Repo: github.com/state-space-...

2 months ago 8 2 1 0

Come check it out if you're interested in time series, Monte Carlo, sequential problems.

We've got a suite of fun examples, lots more to add - contributions welcomed!

Super fun work with @adriencorenflos.bsky.social and Sahel Iqbal 🙌

2 months ago 5 0 1 0
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New open source: cuthbert 🐛

State space models with all the hotness: (temporally) parallelisable, JAX, Kalman, SMC

2 months ago 35 9 1 1
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A Complete Decomposition of Stochastic Differential Equations We show that any stochastic differential equation with prescribed time-dependent marginal distributions admits a decomposition into three components: a unique scalar field governing marginal evolution...

Paper for full details. The proofs draw on ideas from vector calculus and Fourier analysis which was really fun to work through
arxiv.org/abs/2601.07834

3 months ago 0 0 0 0
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Here is the decomposition:

I show that the scalar ϕ is unique(!) but you can choose and Q or D.

In diffusion the ϕ terms represent the "probability flow ODE" but there are actually many ODEs which satisfy p(x,t) depending on your choice of Q

3 months ago 0 0 1 0

This work combines, unifies and generalises two of my favourite papers

- Ma et al - Complete recipe for autonomous SDEs arxiv.org/abs/1506.04696
- Karras et al - Elucidating the Design Space of Diffusion arxiv.org/abs/2206.00364

3 months ago 1 0 1 0
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New preprint! A Complete Decomposition of Stochastic Differential Equations

I characterise *all possible SDEs* that satisfy given time-dependent marginals p(x,t)

3 months ago 4 0 1 0

Not like you to not give the sauce, this looks interesting!

3 months ago 1 0 1 0

Usual MCMC algorithms are typically guaranteed to work well when used to sample from target distributions for which

i) mass is reasonably well-concentrated in the centre of the state space, and
ii) the log-density is smooth and of moderate growth.

Outside of this setting, things can go poorly.

4 months ago 33 6 1 0
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Lattice Random Walk Discretisations of Stochastic Differential Equations We introduce a lattice random walk discretisation scheme for stochastic differential equations (SDEs) that samples binary or ternary increments at each step, suppressing complex drift and diffusion co...

Read more at arxiv.org/abs/2508.20883

Including scaling LRW up to image generation with Stable Diffusion 3.5 🐱

7 months ago 5 0 0 0

As described in the paper, LRW provides multiple benefits but the key motivation for us @normalcomputing.com was the co-design with novel stochastic computing hardware which we believe can drastically accelerate general-purpose SDE sampling.

7 months ago 2 0 1 0
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New paper on arXiv! And I think it's a good'un 😄

Meet the new Lattice Random Walk (LRW) discretisation for SDEs. It’s radically different from traditional methods like Euler-Maruyama (EM) in that each iteration can only move in discrete steps {-δₓ, 0, δₓ}.

7 months ago 16 5 1 1
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In slides from a recent talk - the { virtuous / vicious } cycle of filtering, smoothing, and parameter estimation in state space models.

11 months ago 20 1 2 0
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Oh you king this is great thanks! I was at Lau Pa Sat the other day but went for shrimp noodles (which were great) because the satay queue was too long

11 months ago 2 0 0 0
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Didn’t listen, good decision

11 months ago 1 0 1 0

Me: Hey so where’s good to eat round here?
Singapore taxi driver: Malaysia

11 months ago 2 0 2 0

However! We’re working on a much broader generalisation of abile which hopefully will be able to share soon 🤞🔜

1 year ago 1 0 1 0
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Online Natural Gradient as a Kalman Filter We cast Amari's natural gradient in statistical learning as a specific case of Kalman filtering. Namely, applying an extended Kalman filter to estimate a fixed unknown parameter of a probabilistic mod...

Adjacent!

posteriors takes the natural gradient descent viewpoint on EKF arxiv.org/abs/1703.00209

Which is nice for online deep learning but not necessarily bespoke state-space model inference

1 year ago 4 0 1 0

We've also updated the paper and made some cool updates to the library 😎

Paper: arxiv.org/abs/2406.00104
Repo: github.com/normal-compu...

1 year ago 2 0 1 0

📃 Poster #419
🗓️ Sat 26th, 10:00–12:30
📍 #ICLR2025, Singapore

Swing by if you’re into probml, thermodynamic computing or just wanna say hi

1 year ago 2 0 2 0
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posteriors 𝞡 published at ICLR!

I’ll be in Singapore next week, let’s chat all things scalable Bayesian learning! 🇸🇬👋

1 year ago 11 2 1 0
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A new instalment of office decor:

1 year ago 20 1 3 1

F

1 year ago 1 0 0 0