Leiv Rønneberg
@ltronneberg.bsky.social
Postdoctoral fellow @ University of Oslo (back home in 🏔️🇳🇴🏔️), Bayesian stats (high-dimensional, nonparametric, ML), biostatistics, computation. Previously @ MRC Biostatistics Unit, University of Cambridge 🇬🇧
Yeah, I'm sure there is literature here, I just need to dig a bit! I've been doing some quite crude thresholding so far to decide when things are low-rank 'enough' for the switch. This works sometimes, but seem to also interfere with adaptation of my HMC sampler
November 2, 2025 at 5:49 PM
Yeah, I'm sure there is literature here, I just need to dig a bit! I've been doing some quite crude thresholding so far to decide when things are low-rank 'enough' for the switch. This works sometimes, but seem to also interfere with adaptation of my HMC sampler
Working on something very much in this vein right now actually. I have a super high-dim problem where due to sparsity the problem becomes low rank during sampling. Wanting to then switch from doing inverses via Cholesky to inverses with Woodbury -- but quite fiddly numerically so far...
November 2, 2025 at 5:36 PM
Working on something very much in this vein right now actually. I have a super high-dim problem where due to sparsity the problem becomes low rank during sampling. Wanting to then switch from doing inverses via Cholesky to inverses with Woodbury -- but quite fiddly numerically so far...
oh thanks! my role was tiny though, the first author (a master's student (!)) is fantastic and did the work
October 31, 2025 at 8:41 PM
oh thanks! my role was tiny though, the first author (a master's student (!)) is fantastic and did the work
At a conference this summer a guy referred to papers from the late 90s as «turn of the last century»…
October 31, 2025 at 6:14 PM
At a conference this summer a guy referred to papers from the late 90s as «turn of the last century»…
Been a while since I looked into this but the Hutch++ paper has some optimality results I think as well as some refs to variance reduction techniques arxiv.org/abs/2010.09649 ( from 2021 though, so I'm sure a lot has happened since )
Hutch++: Optimal Stochastic Trace Estimation
We study the problem of estimating the trace of a matrix $A$ that can only be accessed through matrix-vector multiplication. We introduce a new randomized algorithm, Hutch++, which computes a $(1 \pm ...
arxiv.org
October 29, 2025 at 7:38 PM
Been a while since I looked into this but the Hutch++ paper has some optimality results I think as well as some refs to variance reduction techniques arxiv.org/abs/2010.09649 ( from 2021 though, so I'm sure a lot has happened since )
I’d also be interested in this, Martin. How it is structured, what is covered, what the pre-requisites are etc
February 21, 2025 at 4:09 PM
I’d also be interested in this, Martin. How it is structured, what is covered, what the pre-requisites are etc
I think that could indeed be quite illuminating. Often we approach these topics trying to make them practical without requiring too much mathematical setup. You don’t *need* stochastic process theory to get at the core of GP regression, but you might need it to understand the finer details later on
February 21, 2025 at 4:08 PM
I think that could indeed be quite illuminating. Often we approach these topics trying to make them practical without requiring too much mathematical setup. You don’t *need* stochastic process theory to get at the core of GP regression, but you might need it to understand the finer details later on
Interesting post! I helped run a similar module in Cambridge last year were we tried to cram in too much, covering basics of GPs *and* DPs. If the emphasis is on BNP I think one must mention DPs at some point, though it is a step up in abstraction compared to GPs. «distribution of distributions» etc
February 21, 2025 at 1:28 PM
Interesting post! I helped run a similar module in Cambridge last year were we tried to cram in too much, covering basics of GPs *and* DPs. If the emphasis is on BNP I think one must mention DPs at some point, though it is a step up in abstraction compared to GPs. «distribution of distributions» etc
It can be bounded from below and above, by \sqrt{n} and n, respectively. These cases each reflect say an extreme lengthscale, ell=\infty or ell=0, and so it appears almost like a measure of complexity. I'm struggling to come up with an intuitive explanation.
Does anyone have any ideas/references?
Does anyone have any ideas/references?
February 3, 2025 at 8:17 PM
It can be bounded from below and above, by \sqrt{n} and n, respectively. These cases each reflect say an extreme lengthscale, ell=\infty or ell=0, and so it appears almost like a measure of complexity. I'm struggling to come up with an intuitive explanation.
Does anyone have any ideas/references?
Does anyone have any ideas/references?
Maybe I'll add that the call is very general across "computational science", encompassing biology, chemistry, physics etc. alongside maths & stats. Bayesian machine learning is just one of the projects within our department, see the link below
www.uio.no/dscience/eng...
www.uio.no/dscience/eng...
Mathematics & Statistics - dScience – Centre for Computational and Data Science
Read this story on the University of Oslo's website.
www.uio.no
January 13, 2025 at 5:54 PM
Maybe I'll add that the call is very general across "computational science", encompassing biology, chemistry, physics etc. alongside maths & stats. Bayesian machine learning is just one of the projects within our department, see the link below
www.uio.no/dscience/eng...
www.uio.no/dscience/eng...
Are you assuming you are able to compute the derivatives as well, or simply that you know they are non-negative?
January 9, 2025 at 2:08 PM
Are you assuming you are able to compute the derivatives as well, or simply that you know they are non-negative?
Overbygningen er vel laget av stål..?
December 10, 2024 at 10:49 AM
Overbygningen er vel laget av stål..?
It's quite ironic that the term was first coined in a sociological essay warning *against* meritocracy, rather than lifting it up as an ideal.
The Rise of the Meritocracy - Wikipedia
en.wikipedia.org
December 5, 2024 at 4:50 PM
It's quite ironic that the term was first coined in a sociological essay warning *against* meritocracy, rather than lifting it up as an ideal.