David Andersen @daveandersen.bsky.social · 15hI don't know what it is about this semester, but I'm leaving my grad class daily being just astoundingly impressed with the students. We may^H^H^Hwill be be facing an AI education crisis or already are, but this crop of students (early Ph.D., MS, a couple of ugrad seniors) still have the juice. 020
David Andersen @daveandersen.bsky.social · 21hHuh. Apparently now I am a professor in the Griffin School of Computer Science. I choose to believe it's a mythology reference. We should rename our competitive programming team or hacking team the LionEagles. www.cmu.edu/news/stories... 140
David Andersen @daveandersen.bsky.social · 29/09/2026It's mine and you can't take it away from me! 010
David Andersen @daveandersen.bsky.social · 29/09/2026Dear puppy with razor sharp teeth, I will WIN THIS BATTLE, with the POWER OF TECHNOLOGY 010
Reposted by David AndersenDave DiCello @davedicello.bsky.social · 29/09/2026So many film images to go through as of late, but I love how this one came out. The way the clouds are reflecting off of PPG Place in #pittsburgh almost look connected with the clouds in front, making for such an interesting view. 3927
David Andersen @daveandersen.bsky.social · 28/09/2026Nice thread to read. My colleagues in HCI (human computer interaction) like to point out that not only is none of us (CS people) normal, most people we know aren't either, by proximity to a Ph.D. computer scientist. It's risky to look at ourselves and say "oh, this is surely useful!" 1/ 3382
David Andersen @daveandersen.bsky.social · 27/09/2026made gougeres to bring to the block party. It turns out there is such a thing as eating too much puff pastry. don't think I'll be making those again for a while. 🤣 151
David Andersen @daveandersen.bsky.social · 25/09/2026well, that was a little harrowing. First bike-car accident I've ever been in in ~45 years of riding a bike all the time. Driver was signaling left and then decided, as I was going past them, to turn right instead. 201203
David Andersen @daveandersen.bsky.social · 25/09/2026The phone scammers have defeated me. Five or more calls per hour for multiple hours per day making it through Google fi's spam prevention and many bypassing android phone screen. Time for the nuclear option. Hope nobody needs to call me for a while! 😭 110
Reposted by David AndersenDavid Andersen @daveandersen.bsky.social · 21/09/2026Random blog post inspired by someone else's random blog post. Mostly I just love succinct data structures and continue to want the world to know about them. :-) wiredream.com/vowels/wiredream.com 0102
David Andersen @daveandersen.bsky.social · 21/09/2026Oh @verizonofficial.bsky.social FiOS, I am so unimpressed this week You see, you have one part of an ECMP or LAG group that's flaky right by my house. Why? Because specific 5-tuples consistently have 90% outbound packet loss while most others have 0%. The lcr-21 path is the one with a bad sub-link. 210
David Andersen @daveandersen.bsky.social · 21/09/2026Random blog post inspired by someone else's random blog post. Mostly I just love succinct data structures and continue to want the world to know about them. :-) wiredream.com/vowels/wiredream.com 0102
David Andersen @daveandersen.bsky.social · 19/09/2026Oy. The home improvement scam calls have won. I've switched call screening back to screening all unknown numbers, which I hate, because it has a nontrivial false positive rate. Uncertain why Google fi isn't doing a better job against this wave of them. May a pox befall their entire call center 111
David Andersen @daveandersen.bsky.social · 19/09/2026Year 3 of the 5lb CO2 tank. Only got 11 months out of it this time and the price of the refill went up from $13 to $14, but still a huge win over $17 for a 0.9lb refill with exchange for sodastream’s little co2 thingies. $0.06 / liter of carbonated water vs like $0.40/liter. 🤓 110
Reposted by David Andersenc0nc0rdance @c0nc0rdance.bsky.social · 17/09/2026There are two ways you will react to the image below. Never encountered: "Neat! A caterpillar with a little sports jersey on!" Encountered: "Oh god, get it away before it kills us all!" Let's meet the saddleback caterpillar (Acharia stimulea), a tiny bug that that 'hides' a painful sting. 513325
David Andersen @daveandersen.bsky.social · 16/09/2026I got well-ackshully'd by my watch in class today. I failed to turn off the "talk to Gemini by raising your hand to your mouth" thing. It never works but it triggers sometimes writing on the blackboard. I said "the drive's read head parks" and my watch burst out "THAT IS CALLED THE ACTUATOR" dead 051
David Andersen @daveandersen.bsky.social · 16/09/2026me: llm, implement this new pipeline for training a network I want to play with. llm: Sure! Let me do that! (it does) But you told me not to run from 3-9pm when it's peak power so I'll delay launching it. me: it's 10pm. llm: sure! you can override the local clock. (the local clock says 10pm) 🤦🏼 250
David Andersen @daveandersen.bsky.social · 14/09/2026I ❤️ my cargo e-bike. It's let us stay a 1 car family despite two kids. That might change but so far, 3.4 years in, it's cost us about $2k/year and continues dropping as we amortize the purchase price. I'll take that over $15k/year. 🤓 141
David Andersen @daveandersen.bsky.social · 14/09/2026puppy and i are having the same reaction to monday morning* (* ok, this is only partly true. we're both sleepy but I didn't poop on the floor. yet.) 140
Reposted by David AndersenMichael Clemens @mclem.org · 12/09/2026The US President's new proposal to tax international students has been approved by the White House for release this week. It's an unprecedented $100,000 tax on int'l grads who stay to work after graduation on Optional Practical Training (most grads do), a crucial bridge to remaining by any channel. 21432713
David Andersen @daveandersen.bsky.social · 11/09/2026This was worth reading and thinking about mathandai.orgmathandai.orgDeclaration — Math and AIRead the declaration and add your name. 001
David Andersen @daveandersen.bsky.social · 11/09/2026It amuses me that the easiest way to get the dog crate to my office was to take it on the cargo bike - the university seems to frown on the idea of me parking my car on the sidewalk next to the entrance to the building but they have kindly provided a bike rack there. 🤓 150
Reposted by David AndersenDavid Andersen @daveandersen.bsky.social · 08/09/2026Mistakes were made 0101
David Andersen @daveandersen.bsky.social · 06/09/2026I let the garden be taken over by volunteer butternut squash this year, but fortunately, they roasted up very well. Which is good, because there are like five more in there. 220
David Andersen @daveandersen.bsky.social · 04/09/2026niche AI comment: I used to like Artificial Analysis as a way to quickly eyeball models, but their use of TerminalBench 2.1 is making them useless for what I actually care about. It's saturated. Consider below. Gemini 3.8 "wins" TerminalBench 2.1 but is remarkably behind on 4.0, which ... 100
David Andersen @daveandersen.bsky.social · 04/09/2026Daaaaamn. The intersection at Reynolds and Murtland was flooded three feet deep. Saw someone wading across it and decided to find a better way home from the climbing gym. #pittsburgh 380
David Andersen @daveandersen.bsky.social · 03/09/2026As I watch the current cascading outage across AI providers ("claude is down! let's switch to codex! ... oops"), I can't help but ponder again when it will become important for those companies to balance (a) move-fast-AI culture and; (b) keep-things-running SRE culture. Right now they mostly do (a). 2201
David Andersen @daveandersen.bsky.social · 02/09/2026sleeping puppy is best puppy particularly since she's not trying to eat my ankles while asleep. 140
David Andersen @daveandersen.bsky.social · 01/09/2026First attempt at bring your puppy to work day is going pretty well so far, though it took both me + 14yo to manage her effectively through a meeting. :) (Goal is to make sure she's well-socialized to work so that once she's capable of settling more I can bring her regularly.) 150
David Andersen @daveandersen.bsky.social · 01/09/2026😍 www.nber.org/digest/20260... tl;dr: Ambulance time-to-reach-hospital near the congestion pricing boundary in NYC fell from about 12 minutes to 11 minutes (~8%), almost certainly improving patient outcomes. Nice stuff.nber.orgUrban Congestion Pricing and the Response Times of Emergency Medical Services 001
David Andersen @daveandersen.bsky.social · 29/08/2026Now witness the power of this fully prepped and operational burrito station* *It does not make space laser sounds :( 030
Reposted by David Andersendisc horse bot @horsedisc.bsky.social · 28/08/2026Tactical Princess Peach can still happen if people want it bad enough 0539
David Andersen @daveandersen.bsky.social · 27/08/2026Puppy day 6: oh thank god, dr. prof. spouse found the stealth poo and got rid of it 030
David Andersen @daveandersen.bsky.social · 26/08/2026Puppy crate training progress as measured by sleeping heart rate patterns. Good progress. That first night was rough. 020
David Andersen @daveandersen.bsky.social · 25/08/2026Oh my god this woman needs to be interviewed more often www.cbc.ca/radio/asitha...cbc.caB.C. swimmer crosses the Strait of Georgia in under nine hours | CBC RadioWhen it comes to crossing the Strait of Georgia, most people would choose to do so in a boat, a ship — any kind of a marine vessel, really. But not Melanie Buggey. She chose to swim. 152
Reposted by David AndersenRichard Kadrey @richardkadrey.bsky.social · 24/08/2026The Allegheny River this morning Pittsburgh, PA 3627
David Andersen @daveandersen.bsky.social · 24/08/2026Friends with kids at dice: I'm so confused. The text version of the calendar says Jan 21 clerical, Jan 22 professional development days. But the image on that page says Jan 19 clerical, Jan 20 clerical. Anyone know which of these is actually correct or where ground is? www.pghschools.org/calendarpghschools.orgCalendar - Pittsburgh School DistrictPittsburgh Public Schools District Calendar 110
David Andersen @daveandersen.bsky.social · 24/08/2026I love working at a university. ,🤣 (photograph is from today at cmu. This thing is a couple of years old, but I hadn't seen it before..) 110
David Andersen @daveandersen.bsky.social · 24/08/2026Yes, you (admittedly cute) little monster, sleep, sleep, get all of the sleep you didn't get last night while waking me up every 45 minutes. 140
David Andersen @daveandersen.bsky.social · 21/08/2026Oh dear. We seem to have added someone to our family. Nova, meet bluesky. 170
David Andersen @daveandersen.bsky.social · 19/08/2026There's more information needed to dig into this graph from a causal perspective, which would be really useful, but just the fact that AI is so breaking the relationship between homework scores and test scores is itself really painful for education. It's one I'm feeling a lot of for undergrad stuff. 1103
Reposted by David AndersenBWJones @bwjones.bsky.social · 19/08/2026Many years ago, Salt Lake City Utah did the same experiment with the same results. They took the biggest users of social services and housed them along with resources. It was *cheaper* than not doing that and they had better outcomes. 17932
David Andersen @daveandersen.bsky.social · 18/08/2026Decided to treat ourselves a little for our last night in Iceland. Mmmm. 030
David Andersen @daveandersen.bsky.social · 17/08/2026Interesting if you like reading about energy generation pricing and policy: newsletter.semianalysis.com/p/12b-of-us-... (Long and detailed. Perhaps a bit excessively verbose. But it will also make you more annoyed at PJM)newsletter.semianalysis.comFull of Cold Air - PJM's $12B modeling mistakeHow America's greatest grid wasted billions and is putting ratepayers at risk by using bad models, no not those models. 030