After sitting for two months in the editor's hand, our latest manuscript has been finally sent out to the reviewers. Coincidentally, just a couple of days after I sent an email asking about the status of manuscript.
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Giuseppe Bilotta
@giuseppebilotta@fediscience.org
mastodon 4.6.9Researcher @ INGV-OE. Opinions my own.
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23 Posts
Joined May 03, 2022
Replying to
@j_bertolotti@mathstodon.xyz “and I'm not talking about physics simulations”
Replying to
The reason for this is that the process of formation of sugar crystals in #fudge has strong parallels with the formation of crystals in #magma, which is fascinating.
I'm not as surprised as I could be, because this is actually the second time that I come across #food-related physics that is relevant for #geophysics: one of the rheological models that we have implemented in #GPUSPH to study #lava flows is the DeKee & Turcotte model, which is a regularization of the Herschel–Bulkley model that was developed for biological materials, among which food stuff such as honey, yogurt, mayonnaise and banana puree
https://doi.org/10.1080/00986448008912535
Preliminary results for this were presented at the VII Congress on Rheology in 1976, and the DeKee et al contribution, available in the conference proceedings is titled
“Rheological Characterization of Time-Dependent Foodstuffs“
Obviously when I teach #GPGPU I point out that the main point is performance, and “how to measure” is a topic we address. Obviously, the primary metric is kernel runtime. I then introduce the effective bandwidth metric (bytes read + bytes written, divided by time taken by the kernel) which is a good way to compare some similar kernels AND to discuss hardware limits and how close we are to them (I don't always discuss the roofline model though, maybe I should).
When we start to look into more advanced things, we hit the “snag” that sometimes a kernel using a more efficient technique may be _less_ effective at using a particular resource, e.g. by having having a _lower_ effective bandwidth —I do this on purpose to show how kernel runtime remains the ultimate “tell” on how good a kernel is compared to another (regardless of the additional information the effective bandwidth may tell us).
At this point I introduce a metric for which I don't actually know if there is a name: number of elements processed per seconds, which is just the number of elements, divided by the kernel runtime.
I call this effective throughput, but sometimes I get the nagging feeling that this may not be the correct term?
Replying to
@hattom@mastodon.social in GPUSPH we use MIPPS (millions of iteration-particles per second). Other SPH codes use GigaPIPS (billions of particle interactions per second). I should probably go back to read our own papers to check if we used the term throughput (esp. effective throughput) 😁
Replying to
@t_robinart @snap2grid hello, another vote for Scribus and yes, it absolutely has paragraph styles, I use them extensively for the SPHERIC Newsletter. If you want to see it in action, https://www.spheric-sph.org/newsletters the last few issues were created in Scribus.
Replying to
@lemay I'm not ashamed to confess I've been thinking about adding cat photos to posts where I talk about science because my single most successful post is a random one of a cat on a chat. I expected it to be liked because, I mean, Fediverse and cats of course it's going to make numbers, but I never expected it to get spread so much!
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@athas@freeradical.zone hence the joke about the guy in the hot air balloon
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@clew@ecoevo.social let's find a geophysical equivalent and write a scientific paper on this 8-)
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In the mean time I've discovered that the cat is pregnant and the unofficial mascot of the CUS. Her name is couscous apparently (obviously.)
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@OneInterestingFact no problem, we all have our circumstances 8-) And I had been wondering if armchair was indeed the correct term: it didn't make much sense as it didn't have arms, but as a non-native English speaker chair didn't feel correct either (in Italian we'd call something so heavily cushioned a “poltroncina”, a diminutive of “poltrona”, which is an armchair).
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@markd I suspect they put the sticker while the cat is sleeping specifically to avoid the issue. They probably remove it when the cat wakes up so it doesn't suspect anything. Hopefully the cat won't come across this post, or the folks at the office will have been busted by my indiscretion ;-)
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@OneInterestingFact thanks for the correction.
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@clew@ecoevo.social wait, was it a joke? Does a spodosol cake actually exist? 8-D
Need to prepare the images for the extended abstract for the 20th #SPHERIC. My mind is already on vacation. These are going to be the hardest-to-make images I've ever made.
Our latest submission to JCP has been rejected as “out of scope” because the editor has interpreted the paper as being “an application”. A curious decision, since the paper is on how to compute acoustic terms efficiently and with higher precision compared to how it's usually done, and there are several applications, not one, where we show how this improves energy conservation and numerical stability in general.
The fact that the decision was taken by the editor *after* sending the paper out to reviewers, but claiming that it was made to avoid going through the review process, and that he only sent it to reviewers *after* I prodded him *after* the manuscript had been laying on his desk for months makes me doubtful of the, shall we say, correctness of the whole thing.
Now the big question is: should we challenge the decision, or should we just drop it and go with a different journal?
I want to simulate this with GPUSPH
From time to time I get a student whose exam project is good enough to be a thesis for their degree, and I feel embarrassed because mine is only a 6 CFU subject and the only thing I can do is give them top marks.
(Yes, they usually already have a thesis supervisor.)
OK I'm going to need ask the Fediverse for some math help here, because I have a feeling I'm forgetting something obvious and can't find the resources I'd need to answer my own question.
Let's say I have an underdetermined linear system. The methods generally employed to solve these find the least (l2) norm solution, which is generally acceptable.
However, in my case, I need to find solutions that satisfy some constraint (simple inequality constraints: solution must be in a box, with known ranges [min max] for each variable).
I think I have had a brain freeze because the only approach I can think of to solve this is to turn the problem into a constrained optimization problem. However, in my case (hundreds of thousands of variables) this is not computationally feasible: the time needed for the optimization approach is ridiculously higher than the standard linear system solution.
OTOH, I have a vague feeling that it should be possible to approach this differently, possibly remaining in the domain of the linear system resolution. What am I missing?
Replying to
@athas@freeradical.zone I have to be careful about this with my students. Thinking in general terms can be useful because it can guide you in the right direction (e.g. identifying that something is a reductoin or a scan means one can leverage common paradigms for an efficient implementation), but one may end up missing task-specific aspects that can be beneficial.