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Robert Jacobson
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Below is my response to a recent invitation for me to share my thoughts about how the grad program I earned my Ph.D. in might improve their program. These comments are probably applicable to virtually every mathematics Ph.D. program.

Looking back, I recognize that a lot of my peers in grad school suffered from depression and isolation. Grad school is by definition an unbalanced time in one's life. But I wonder if there is more the department could do to decrease the uncertainty students face about what is expected of them, what their path to graduation is, and so forth. This is easier said than done, but surely many other programs have faced this problem and found things that help. Maybe regular panel discussions about topics like: how to find and choose an advisor, strategies for post-qual research, stories of how others have successfully navigated their graduate experience, how to manage finances as a grad student, etc. That's just one idea. It's easy to feel extremely isolated as a grad student. After I graduated, I started talking to my grad school friends about the psychological and emotional challenges we faced. I was fascinated to learn that my peers' experiences were much closer to my own than I knew. Many of them were on anxiety and antidepressant meds, a few experienced divorce or other significant strains in their personal relationships, some related serious hardships dealing with their advisors (for a variety of reasons)... and these are my peers that have been the most successful, graduating, landing excellent jobs, and running into me at the Joint Math Meetings.

It is part of the culture of mathematicians to exclude our personal stories and experiences from our professional presentation of ourselves, and senior faculty are often especially averse to attending to the non mathematical part of the graduate experience. It seems to me, though, that earning a PhD in mathematics today is a very different experience from earning one in 1973, and supporting students in non mathematical ways is not only the humane thing to do, it benefits mathematics and improves the quality of mathematicians the program produces. I'm probably preaching to the choir, here.

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When you surf the web looking for new ways to spice up your first semester calculus course but wander into the wrong part of town...
Secrets revealed: How mathematicans really talk to each other about adaptive online learning...
How to name your algorithm the night of the submission deadline. 

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Gyroid made from a single shape of developable strip
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2 Photos - View album

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Are you in the market for a new calculator? Don't settle for those cheap 8 digit knockoffs! 

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Science funding should be a political no brainer. An abundance of commercial spinoffs and jobs, a more technically capable workforce, advances in health and quality of life galore, a leg up in the international economy... every industry and every person enjoys tremendous returns on society's investment in science. This shouldn't be a partisan issue. 

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The status of gpgpu programming on the Mac

CUDA: nVidia only, so not on iMacs.
OpenCL: Apple ships OpenCL on every Mac, which is great! Except even the minimal example code in their documentation doesn't compile.
AMD's new ROCm/HIP/HCC: Looks super cool, but super beta, and apparently only works on Linux with the latest hardware.
Apple's Metal: The most proprietary and iosyncratic technology in the bunch, it only exists on macOS El Capitan or later, and then only on some Macs built after 2012 (e.g. MacBooks need to be 2015 or newer), which excludes my aging but still quite capable iMac on which I do most of my programming work. This is clearly not intended for researchers.

The most frustrating thing is that OpenCL is so uselessly broken and has been since the beginning. Two years ago big name projects and developers opened up about abandoning the platform. The problem is you can't upgrade the drivers on macOS like you can on Windows or Linux. You are stuck at Apple's mercy.

This is about as bad as it gets. CloudFlare is a service that sits between a website and the website’s users that makes it easier for the website to serve its data to users around the globe. A vast number of websites use CloudFlare. One internet technology company reports, “CloudFlare is used by 71.8% of all the websites whose reverse proxy service we know” ( Because of how CloudFlare works, even on websites that use encrypted connections (HTTPS), the websites’ data flows through CloudFlare unencrypted before being sent to the user.

It turns out a flaw in CloudFlare’s systems caused unencrypted data from one website to be served up along with the data from another website on accident.

It used to be that the worst case scenario for internet security was if a flaw in a website allowed any unauthorized person to access secret information on that website. Something much worse has happened. Someone browsing might inadvertently be sent a little data, a private message perhaps, meant for an user.

But it’s much worse than just that. Search engines like Google and Bing crawl the web, downloading websites and storing them in massive caches to be indexed and searched. So let’s say Google’s web crawler is the “person” who accessed and was sent that private message from Now that private information is searchable on Google. In other words, CloudFlare has for months been spraying unencrypted private information like a firehose all across the internet—private messages from major dating sites, full messages from a well-known chat service, online password manager data, frames from adult video sites, hotel bookings, passwords, keys… A quick search of an incomplete list of affected websites turns up 3,662 sites with “bank” in the name. Search engines are still working to purge their caches of this data.

Regardless of who you are, you need to change your passwords. Now is a great time to adopt a password manager like 1Password. Since you will be changing your passwords anyway, adopting 1Password isn’t any extra work. Ironically, uses CloudFlare, but 1Password designed their security system specifically to protect against unforeseen scenarios like this, so 1Password was not affected by the security breach. (

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Groups like DataRefuge and the Environmental Data and Governance Initiative, which organized the Berkeley hackathon to collect data from NASA’s earth sciences programs and the Department of Energy, are doing more than archiving. Diehard coders are building robust systems to monitor ongoing changes to government websites. And they’re keeping track of what’s already been removed—because yes, the pruning has already begun.

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Mathematicians Aaron Broussard, Martin Malandro, and Abagayle Serreyn have cracked the code for the optimal video game multi-jump, a normal jump followed by additional jumps initiated in midair without the aid of a platform, to determine the highest achievable jump, and have described strategies human players or AI can use in real time to select successful multi-jumps in real time. Their results (doi) are published in the December issue of The American Mathematical Monthly . From the paper's introduction:

_A multi-jump is a finite sequence of jumps where the first jump is initiated from the ground and the rest are initiated in midair. The number of jumps in a multi-jump is the length of the multi-jump, so a double jump is a multi-jump of length two. Several video games, such as Chair Entertainment Group(R)’s Shadow Complex(TM) and Nintendo(R)’s Super Smash Bros.(TM) Melee, feature triple jumps or multi-jumps of even longer length. _

_The basic problem we consider in this paper is the following. Suppose that a character in a two-dimensional side-scrolling video game wishes to use a multi-jump to jump to the right from a fixed starting point across a gap and land on a fixed platform. ...We therefore assume that the character has a known finite sequence of jump arcs available to her and faces the problem of selecting when to jump in midair, i.e., to switch from the arc of one jump to the next, so as to land on the platform. ..._

_Provided the platform is reachable by a multi-jump, we give strategies for solving this problem on the fly for both player-controlled and artificial intelligence (AI)-controlled characters. In the simplest situation all jumps available to the character are equal and fully concave (Definition 5). In this situation we give a simple strategy (the line method) that is usable by both players and AI. In our experience the majority of games featuring multi-jumps are covered by this situation. We give two further strategies for AI-controlled characters in more-complicated situations. Our first AI strategy is very general, in that it applies to any collection of standard jump functions (Definition 1). We also give a faster (less computationally intensive) AI strategy for collections of standard jump functions whose derivative inverses are known and computable exactly._

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I'm a little late to this party, but is a fun new website that let's you rat out professors who “promote anti-American values.” Academics have apparently been submitting their hearts out in the two days since the website went live, but none of the new submissions seem to be appearing on the list. Among those already brought to account who will be the first with their backs against the wall when the revolution comes: Dr. Emit Lathrop Brown, Dr. Bunsen Honeydew, Dr. Henry "Indiana" Jones, Professor Quirinus Quirrell, Dr. Pepper, and The Doctor. #trollprofessorwatchlist #trollprofwatchlist
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