Tuesday, February 28, 2017

"Numerical Methods for the Computation of the Confluent and Gauss Hypergeometric Functions"

My paper on computation of confluent and Gauss hypergeometric functions, from a project that started in Spring 2009, finally is not only out in a journal but now even has coordinates (volume, page numbers, etc.) Here are the details.

Title: Numerical Methods for the Computation of the Confluent and Gauss Hypergeometric Functions

Authors: John W. Pearson, Sheehan Olver, and Mason A. Porter

Abstract: The two most commonly used hypergeometric functions are the confluent hypergeometric function and the Gauss hypergeometric function. We review the available techniques for accurate, fast, and reliable computation of these two hypergeometric functions in different parameter and variable regimes. Themethods that we investigate include Taylor and asymptotic series computations, Gauss–Jacobi quadrature, numerical solution of differential equations, recurrence relations, and others. We discuss the results of numerical experiments used to determine the best methods, in practice, for each parameter and variable regime considered. We provide "roadmaps" with our recommendation for which methods should be used in each situation.

Our Matlab code is available from this website.

Monday, February 27, 2017

A Putz Hitting a Mench with a Pitch (and Another Baseball Naming Oddity)

One of my all-time favorite baseball box scores is for a game in which a Mench* was hit by a pitch thrown by a Putz. Naturally.

* It's too bad that Kevin Mench's last name isn't spelled "Mensch". (And here is a definition page for the Yiddish word putz.)

But my favorite baseball name-combination game is the following: In (at least) one game in 1998 (I think quite a few), the Cincinnati Reds had an outfield of Young, Frank, and Stynes.

(The players were Dimitri Young, Mike Frank, and Chris Stynes.)

There are other good ones as well (e.g., the Giant hardware, with a battery of pitcher (Bud) Black and catcher (Steve) Decker).

Saturday, February 25, 2017

"The Mechanical Universe" Videos Now on YouTube

The videos of The Mechanical Universe are now on YouTube. This gives me flashbacks to my Physics 1a with David Goodstein at Caltech. (My physics teacher in high school showed us many of these videos, and then I had an odd sense of deja vu when I had Goodstein as a lecturer in the fall term of my frosh year at Caltech.)

(Tip of the cap to Guillermo Valle Pérez.)

Friday, February 24, 2017

Excerpts of an Interview with Steve Strogatz about Math

Here are some excerpts of an interview with Steve Strogatz about what mathematics is, teaching math, learning math, and more.

There's some really good stuff in here!

Tuesday, February 21, 2017

RIP Ken Arrow (1921–2017)

Ken Arrow, who was the youngest recipient of the Nobel Memorial Prize in Economics, has died

Like many Nobel-memorial laureates in economics, Arrow has an undergraduate degree in mathematics (in his case, as part of a double major with social science). He also earned a Masters degree in mathematics. Arrow has an entry in the Mathematics Genealogy Project.

Some of my students have heard me mention "impossibility theorems" in voting and social choices. If you're going to name one pioneer in that area, that person is Ken Arrow.

(Tip of the cap to Jennifer Nicoll Victor.)

A Mandelbrot Pancake

This article about a very special instance of "Fatou's Day" includes a picture of a Mandelbrot Pancake.

A Mandelbrot Pancake is not quite as cool as a Sierpinski Hamentaschen, but it's still rather awesome.

Sunday, February 19, 2017

An Emotional Outlet

I love this picture!

My Slides on Data Ethics for Mathematicians (and Others)

I have made some slides on data ethics for mathematicians (and others). I'll be presenting them later this term to my graduate course in network science.

Maps of Imaginary Places

Take a look at the fantastic maps of imaginary places in this blog entry by Maria Popova.

Saturday, February 18, 2017

A Table of Perverse Incentives in Academia

I can't argue with this table.

It would also be relevant to include a line for "tenure", because that too has a very good intended effect (time to work on impactful blue-skies research without undo pressure and harmful immediacy) and unfortunate side effects (e.g., slacking, dead weight, insufficient accountability on certain things).

Update: There are some worthwhile comments in my associated Facebook post.

Friday, February 17, 2017

The Making of Ms. Pac-Man

This is a really cool article about the making of Ms. Pac-Man.

"Macrae: The fourth monster in Ms. Pac-Man is named Sue, which is my sister. I always get to joke about that with her a little bit. I worked really hard to make sure I could name a monster after my sister. It was a great way to take an inside poke at her."

I was always wondering how the orange ghost went from Clyde in Pac-Man to Sue in Ms. Pac-Man.

Amazingly, it's now been just over twice as long between the Ms. Pac-Man/Galaga dual arcade cabinet and now than between the debut of Ms. Pac-Man and that commemorative release.

And as some of you have witnessed, I had mad skillz at that game.

The Best Thesis Defense is a Good Thesis Offense

Here's an excellent thesis-defense flyer.

(Tip of the cap to Easter Eggs in Scientific Papers.)

Thursday, February 16, 2017

A Musician Called "Dedekind Cut"

I was looking through LA Weekly, and I did a double-take when I saw that some musical artist known as "Dedekind Cut" is performing soon in LA.

I hope the music is rational.

The new EP, by the way, is called "The Expanding Domain" (for real).

In case you're interested, here is a link to the Wikipedia entry for the mathematical version of a Dedekind cut.

Wednesday, February 15, 2017

"The White House": A New Film by The Coen Brothers

Many years from now, some kids who don't know history are going to express skepticism that "It couldn't have happened like that. That's way too ridiculous and unrealistic!"

And I'm going to respond by telling them to get off my lawn.

(I look forward to the Coen Brothers version. Because we are in a Coen Brothers movie right now. It's like watching a train wreck in slow motion from a seat on the train.)

Also: Truth is stranger than fiction. Never doubt that.

Update: By the way, Frances McDormand would make a spectacular Bettsy DeVos.

Update: Last year, I referred to the Brexit fiasco as something out of a Coen Brothers film (and I included the train-wreck comparison), but the way things have been playing out in the US (including last year, but especially since the election) is, hands down, even more extreme in that direction.

New App: "Make Trump Tweets Eight Again"

This app is funny. It's admittedly somewhat rude, but it's also merited.

(Tip of the cap to Alain Barrat.)

Monday, February 13, 2017

Nomenclature for a Few London Tube Stations

This very interesting article has some really cool stuff about the origin of the names of a few stations in the London Underground ("The Tube") transportation system.

"Mesoscale Analyses of Fungal Networks as an Approach for Quantifying Phenotypic Traits"

Another of my papers just came out in final form, and in fact it appears consecutively with another of my papers. It too has been available for quite a while in the journal, but we finally have our coordinates (page numbers, etc.).

Along with this paper, we have released a large data set of fungal networks. We hope that you enjoy playing with the data!

Here are some more details.

Title: "Mesoscale Analyses of Fungal Networks as an Approach for Quantifying Phenotypic Traits"

Authors: Sang Hoon Lee, Mark D. Fricker, and Mason A. Porter

Abstract: We investigate the application of mesoscopic response functions (MRFs) to characterize a large set of networks of fungi and slime moulds grown under a wide variety of different experimental treatments, including inter-species competition and attack by fungivores. We construct 'structural networks' by estimating cord conductances (which yield edge weights) from the experimental data, and we construct 'functional networks' by calculating edge weights based on how much nutrient traffic is predicted to occur along each edge. Both types of networks have the same topology, and we compute MRFs for both families of networks to illustrate two different ways of constructing taxonomies to group the networks into clusters of related fungi and slime moulds. Although both network taxonomies generate intuitively sensible groupings of networks across species, treatments and laboratories, we find that clustering using the functional-network measure appears to give groups with lower intra-group variation in species or treatments. We argue that MRFs provide a useful quantitative analysis of network behaviour that can (1) help summarize an expanding set of increasingly complex biological networks and (2) help extract information that captures subtle changes in intra- and inter-specific phenotypic traits that are integral to a mechanistic understanding of fungal behaviour and ecology. As an accompaniment to our paper, we also make a large data set of fungal networks available in the public domain.

"Time-Dependent Community Structure in Legislation Cosponsorship Networks in the Congress of the Republic of Peru"

One of my papers just came out in final form. (Also, you can download our data.) It has been available for quite a while in the journal, but we finally have our coordinates (page numbers, etc.). Here are the details.

Title: "Time-Dependent Community Structure in Legislation Cosponsorship Networks in the Congress of the Republic of Peru"

Authors: Sang Hoon Lee, José Manuel Magallanes, and Mason A. Porter

Abstract: We study community structure in time-dependent legislation cosponsorship networks in the Peruvian Congress, and we compare them briefly to legislation cosponsorship networks in the US Senate. To study these legislatures, we employ a multilayer representation of temporal networks in which legislators in each layer are connected to each other with a weight that is based on how many bills they cosponsor. We then use multilayer modularity maximization to detect communities in these networks. From our computations, we are able to capture power shifts in the Peruvian Congress during 2006–2011. For example, we observe the emergence of 'opportunists', who switch from one community to another, as well as cohesive legislative communities whose initial component legislators never change communities. Interestingly, many of the opportunists belong to the group that won the majority in Congress.

Sunday, February 12, 2017

The Most Lucrative Food Crop in Each State

Note to self: I need to have pecans the next time I go to Santa Fe Institute.
Also: It pleases me that "maple syrup" is the item in Vermont, it's fitting that California is still "grapes", and I had no idea about shrooms in Pennsylvania.

Saturday, February 11, 2017

Fake Gnus

I am spreading fake gnus.

(This had to be done.)

I also created this selection of fake gnus, though of course with images drawn from various sources online.

Published Version of "88 Lines About 44 Mathematicians"

In 2009, I wrote a parody of the song 88 Lines About 44 Women that was much more mathematically oriented. A version of this song has now been published in Journal of Humanistic Mathematics. The version that I submitted to the journal is slightly censored. I think I only changed one word, which one will often see when comparing the album version of a song to versions that receive radio airplay.

Here are some article details.

Title: 88 Lines About 44 Mathematicians

Author: Mason A. Porter

Abstract: Well, there isn't really an abstract per se.

Note: In 2014, somebody else recorded a song by the same name on YouTube, although the lyrics are entirely different. Also, that guy focused much more on mainstream mathematicians than I did.

Friday, February 10, 2017

"Dynamics of a Human Spiral Wave"

The authors tried to get us to make a human spiral wave at the 2015 Snowbird meeting on applied dynamical systems. Unfortunately, despite (because of?) our expertise in nonlinear systems, we failed.

Thursday, February 09, 2017

Tales from the ArXiv: A "Topological Middle Class"

This new arXiv paper, by Dani Bassett and company, has a lovely turn of phrase, a "topological middle class", which twist on the classical term rich-club phenomenon. Previously, in this paper, my collaborators and I introduced the term "poor-club phenomenon" via a similar play on words.

Tuesday, February 07, 2017

What Have People Been Googling Since the Election?

This probably says a lot about my sense of humor, but I think the funniest state googling lead, hands down, is Mississippi (especially in the context of what everybody else is asking about). People in that state have googled "3 Doors Down" more than any other state.

(Tip of the cap to George Takei.)

"Make Regression Great Again"

The new comic strip by PhD Comics is timely.

We can talk later about maximum likelihood estimation.

P.S. I stole the title from Won Chang's comment on the Facebook post by PhD Comics.

Saturday, February 04, 2017

"America First" Spoofs

These spoofs are brilliant.

More are apparently in the works.

Update: In addition to the ones compiled on the webpage above, I have seen one for Kazakhstan (which I saw via suggested YouTube videos from one of the ones above). I'll post a link to a page that has a comprehensive compilation once I find one.

Update (2/07/17): Here is a compilation of parodies from European Union countries. Right now, there are many grayed-out flags for ones that don't yet exist, but I'm sure many of them will be filled in eventually.

Update (2/09/17): Yesterday I noticed that the above compilation site has expanded to include countries across the globe. However, it doesn't include the one from Mars. :)

Civ VI: Conducting Holy Wars for Fun and Profit

In Civ VI, if certain apostles die in holy battle, a relic is created.

But how can there not be an Achievement Unlocked for the way I did it? I took over a different Civ's apostle, following a different religion from mine, and then I got it killed by attacking a third Civ's apostle (from yet another religion).

Well, at least I get to keep the relic and earn some tourism points.

Thursday, February 02, 2017

Dove: Trolling with "Alternative Facts" Ad

This is both hilarious and fantastic. Way to go, Dove!

Also, it's particular style reminds me a bit of Hunter Pence Signs.

(Tip of the cap to George Takei.)

Tales from the ArXiv: Participants Viewing a Random Walk

My collaborator Dani Bassett has gotten a bit meta about community structure.

Here is a choice quote from their abstract: "How human learners exploit this information remains an essential question. Here, we focus on the temporal constraints that govern such a process. Participants viewed a continuous sequence of images generated by three distinct walks on a modular network."

This is a missed opportunity: They could have used the Zachary Karate Club for these experiments. (It's probably still worth writing up a short blurb about this paper for the Improbable Research blog.)