Tuesday, July 31, 2018

"Topological Data Analysis of Continuum Percolation with Disks"

One of my papers came out in final form today. Here are some details and a story.

Title: Topological Data Analysis of Continuum Percolation with Disks

Authors: Leo Speidel, Heather A. Harrington, S. Jonathan Chapman, and Mason A. Porter

Abstract: We study continuum percolation with disks, a variant of continuum percolation in two-dimensional Euclidean space, by applying tools from topological data analysis. We interpret each realization of continuum percolation with disks as a topological subspace of [0,1]^2 and investigate its topological features across many realizations. Specifically, we apply persistent homology to investigate topological changes as we vary the number and radius of disks, and we observe evidence that the longest persisting invariant is born at or near the percolation transition.

And to give a story, or at least the hint of the interesting relationship that I sometimes have with typesetters and editors, here is a note that I received from them while we were working on the galley proofs.

Update (8/05/18): A nice way of phrasing things is that we're in a nonassociative situation, and hyphens are a great tool to indicate exactly (and tersely) where the parentheses should be to group terms in a way that renders their meaning unambiguous. (And, naturally, if somebody makes a change in my text that I don't like, my immediate desire is to change it back.)

Monday, July 30, 2018

A Cartoon Depiction of Deep Learning Versus Traditional Machine Learning

So true. :)

(Tip of the cap to Michael Stumpf.)

The Paradox of PLOS One and Scientific Reports

Whenever I see somebody bragging about getting a paper published by a trashy journal like PLOS One or Scientific Reports, I inevitably wonder whether they're being serious (but naive) or whether they're trolling people. Seriously, I can't tell.

Also, remember the mantra: FIPO (= "Fuck it. PLOS One.")

Sunday, July 29, 2018

Tales from the ArXiv: "Blueberry Earth"

I am amused. :)

(However, I do wish that the author had used the subjunctive in the 'what if' question.)

Update: Here is the first paragraph of the Summary: So, to sum up, to a person standing on the surface of the Earth when it turns into blueberries, the first effect would be a drastic reduction of gravity. Standing on the blueberries might be possible in theory, except that almost immediately they begin to compress rapidly and air starts erupting everywhere. The effect is basically the worst earthquake ever, and it keeps on going until everything has fallen 715 km. While this is going on everything heats up drastically until the entire environment is boiling jam and steam. The end result is a world that has a steam atmosphere covering an ocean of jam on top of warm blueberry granita.

Saturday, July 28, 2018

Complex Variables and the Meaning of 𝛏

This tweet speaks the truth!

Two remarks:

(1) One of the main purposes of taking complex analysis is learning how to properly write Greek letters.

(2) I specifically practiced how to draw \xi when I took complex analysis.

(Tip of the cap to Dave Richeson.)

Smurfy Peer Review

Resolved: I am going to start taking inspiration from The Smurfs when I write referee reports for articles that particularly annoy me.

To wit:

"Where did the authors smurf up this idea?"

"This figure is smurfed."

"The authors might want to consider smurfing the abstract a little bit more."

Update: I know; I know: this isn't very smurfy of me.

Update 2: "A total smurf job."

Tuesday, July 24, 2018

Tales from the ArXiv: Low and High Mason Numbers

Here is a new paper on the ArXiv.

Here is a quote from the abstract: In the limit of low Mason number, the dynamical system admits a periodic solution in which the magnetic moment of the swimmer tends to align with the magnetic field. In the limit of large Mason number, the magnetic moment tends to align with the average magnetic field, which is parallel to the axis of rotation.

I operate in the limit of low Mason number, and I claim that this limit is singular.

Monday, July 23, 2018

Opinion: "Are Theoretical Results 'Results'?"

I agree strongly with Ray Goldstein: YES!!!!!!

Moreover: Hell yes!

This is a major issue for interdisciplinary students and postdocs (and more senior scholars), and this is a very helpful paper for them to read as they navigate these waters. I also really like the fact that Ray included two different versions of a 'Results' section in his opinion article.

"Quasiperiodic Granular Chains and Hofstadter Butterflies"

Our article just came out in final form today. It provides the cover picture of an issue of Philosophical Transactions of the Royal Society A. Here are some details.

Title: Quasiperiodic Granular Chains and Hofstadter Butterflies

Authors: Alejandro J. Martínez, Mason A. Porter, and Panayotis G. Kevrekidis

Abstract: We study quasiperiodicity-induced localization of waves in strongly precompressed granular chains. We propose three different set-ups, inspired by the Aubry–André (AA) model, of quasiperiodic chains; and we use these models to compare the effects of on-site and off-site quasiperiodicity in nonlinear lattices. When there is purely on-site quasiperiodicity, which we implement in two different ways, we show for a chain of spherical particles that there is a localization transition (as in the original AA model). However, we observe no localization transition in a chain of cylindrical particles in which we incorporate quasiperiodicity in the distribution of contact angles between adjacent cylinders by making the angle periodicity incommensurate with that of the chain. For each of our three models, we compute the Hofstadter spectrum and the associated Minkowski–Bouligand fractal dimension, and we demonstrate that the fractal dimension decreases as one approaches the localization transition (when it exists). We also show, using the chain of cylinders as an example, how to recover the Hofstadter spectrum from the system dynamics. Finally, in a suite of numerical computations, we demonstrate localization and also that there exist regimes of ballistic, superdiffusive, diffusive and subdiffusive transport. Our models provide a flexible set of systems to study quasiperiodicity-induced analogues of Anderson phenomena in granular chains that one can tune controllably from weakly to strongly nonlinear regimes.

This article is part of the theme issue ‘Nonlinear energy transfer in dynamical and acoustical systems’.

Sunday, July 22, 2018

I Would Code Anything for Love (but I Won't Code That)

Somebody clearly wants an Ig Nobel... Wow.

(Also, I am highly amused!)

Money quote from the programming language's GitHub page:

"Rockstar is a dynamically typed Turing-complete programming language.

Rockstar is designed for creating computer programs that are also song lyrics, and is heavily influenced by the lyrical conventions of 1980s hard rock and power ballads."

Update (7/23/18): I wrote a blurb about Rockstar for the Improbable Research blog.

Saturday, July 21, 2018

Scientific Nomenclature: The "Thagomizer"

This is so awesome!

(Tip of the cap to C E Watkins.)

"Smooths" Versus "Smoothes"

A new champion was crowned recently.

Update: Also, this may be Microsoft's fault.

Friday, July 20, 2018

Proof of Existence of Sunlight in England

At least it was a book that was published in The Other Place. ;)

Thursday, July 19, 2018

A Buzzcock Conjecture

Just give me an excuse to make music-lyric (or certain other pop culture) jokes — any excuse at all.

You can also take a look on Twitter.

Wednesday, July 18, 2018

Tales from the ArXiv: Don't Feed Random Walkers After Midnight

There is a new paper on arXiv about reactive random walkers.

Quoting from the abstract: "The model is highly versatile, as the motion of the walkers can be fed on topological properties of the nodes..."

Comment: But don't feed them after midnight.

Dodgers Trade for Manny Machado!

It's now official (after some increasingly hot rumors, especially yesterday at the All-Star Game): The Dodgers have traded for Manny Machado, the biggest ticket on this season's trade market. Hell yes!!!!

With Corey Seager out for the year, having Machado to play shortstop the rest of the year is most excellent indeed!

Tuesday, July 17, 2018

Medieval Fantasy City Generator

This is so cool!

I also wonder if it uses any generative-model ideas from urban analytics and/or complex systems?

(Tip of the cap to Dungeons and Dragons Memes.)

Monday, July 16, 2018

Heart and Caffeine Plushies

I bought Heart a couple of months ago, and Caffeine just arrived today.

"Message-Passing Methods for Complex Contagions"

Here is the published version of a the chapter that James Gleeson and I wrote for the book Complex Spreading Phenomena in Social Systems, which was edited by Sune Lehmann and YY Ahn. You can also find preprint versions of many chapters available for free on this website.

XKCD: "Negative Results"

I am amused.

Friday, July 13, 2018

Creating Wikipedia Entries for Underrepresented Scientists and Engineers

As described in this article, physicist Jess Wade has been doing incredible work on writing new Wikipedia entries.

Wednesday, July 11, 2018


If I recall correctly, I encountered this one when purchasing theatre tickets at a certain venue in Oxford.

Real-Life Elliptical Billiard Table

I approve!

Now we just need real-life Sinai and stadium billiards (and, of course, a mushroom billiard, to make Lyonia happy).

(Tip of the cap to Alex Bellos.)

Update: The table pictured in the article appears to be a circle, rather than a more general ellipse.

Algorithmic Author Ordership

I am amused. :)

Tuesday, July 10, 2018

Awesome Close-Up Photos of Snails

You can snail, you can snail...

(Tip of the cap to Invisible Scientist.)

Thursday, July 05, 2018

My Eponymous Agent-Based-Model (ABM) Simulator

(Tip of the cap to Sang Hoon Lee.)

Tuesday, July 03, 2018

"My" Eponymous Band

As some of you know, there is a band called Mason Porter. We both show up near the top of Google search for "Mason Porter" (and similar items). Over the years, I have been tagged on several Twitter posts instead of them. I am also followed by a few random people who are interested in folk and bluegrass music, and I have even had some good-natured Twitter battles with the band when I visit Philadelphia.

And now, on this occasion, even the band itself accidentally tagged me in their Facebook post instead of themselves!

Rock on! ("Folk on?")

One of these years, I seriously need to crash one of their shows with a short mathematics lecture.

Monday, July 02, 2018

"International Conference on Newfangled Methods"


Sunday, July 01, 2018

What Happens in Newcastle Stays in Newcastle (2018 Edition)

I've been visiting friends in Newcastle the last couple of days.