Chasing Rabbits: Why Tuomas Sandholm Almost Always Wins
The winding career path of Tuomas Sandholm has taken detours through kidney transplants, Texas Hold ’em, windsurfing and more. Next, he’d like to save the planet.
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“The breadth of the work he does is unique,” says Kevin Leyton-Brown, professor of computer science at the University of British Columbia in Vancouver, Canada, and a leader in AI research. “It spans an area from computer science to micro-economic theory. And he’s one of a small group of people whose work is more applied and who really builds things.”
One algorithm Sandholm created matches living kidney donors from around the United States with people who need a transplant, wading through a sea of data to find optimal matches — thus helping thousands of people get life-saving transplants.
The work he did writing programs that allow companies to buy goods and services more efficiently has helped save some of the globe’s biggest companies billions of dollars and helped make products cheaper for consumers. Other work has helped make advertising more efficient.
The result of all of this, Lesser says proudly of his protégé: “When you talk about the superstars in the field, he’s one of them.”
Earlier this year, an algorithm Sandholm created with Noam Brown, a Ph.D. student at CMU, won a poker contest. They named it Libratus; it beat some of the world’s best human players at no-limit Texas Hold ’em in a competition at Rivers Casino.
Though Brown and Sandholm concede designing poker-playing bots is fun, it was always with the aim of loftier goals. The algorithmic concept behind it — solving what AI folks call “incomplete-information games” where you only know some of what your opponent has or wants — is expected to benefit business, security and even medical situations.
Incomplete information games involve many, many more possible outcomes than, say, chess. In poker, one player never knows exactly what the other players are holding or which cards are already on the table, let alone if anyone is bluffing. Compare that to chess, where a computer can see every piece being played at all times. The added difficulty of teaching a program to master Texas Hold ’em led the AI community to deluge Sandholm with plaudits after his victory.
What binds the three major research areas of Sandholm’s career to date — business applications, the kidney exchange and poker — is the task of searching through a massive number of possible solutions in order to find an optimal (or near-optimal) one.
“It’s about deeply understanding the problem and knowing what details are not really important,” says Lesser, who believes Sandholm could eventually win a Turing Award, the highest honor in computer science, for his work. “From a tech perspective, he’s been a real genius on this.”
As Sandholm’s reputation grew and the success of his efforts began paying off, he found himself drifting back to that summer nearly 40 years ago when the cod disappeared from Helsinki. Surely, after tackling kidney allocation, helping some of the world’s biggest businesses become more efficient and solving what was not long ago thought to be an unsolvable poker game, he could help the environment.
“There are a lot of intellectually interesting topics to do research on. And only a tiny fraction of those will ever make the world a better place,” Sandholm says. “But at the intersection of what is interesting and what is going to make the world a better place if it succeeds, there are unlimited research topics.”
And once he does find the planet-saving topic to focus on? Fong says her husband’s singular focus becomes almost hard to comprehend as he strings 16- to 18-hour days together.
“He just gets this idea, and he just does it,” she says.
Brown, the Ph.D. student who worked with Sandholm on Libratus, has seen that up close and says there is a particular part of Sandholm’s character that might get missed: “He’s a competitive guy and I think that’s good for this field. I’m kind of the same way myself. And being competitive is primary to being successful in general, I think.”
Competition. That word comes up about Sandholm quite often. He says it helps steer his focus.
“I like the type of performance-oriented computer science,” he says. “I don’t really separate it from academics. I think most of academics should be like that. In many fields, it is like that. But other fields steer away from that on purpose. But I’m not like that. So we go for the messiest, toughest, first — instead of looking at the simple abstraction.”
For example, when he began his work on the kidney algorithm, there were other teams trying to come up with a similar program. But Sandholm thought he could do it better. And when he began working on poker, he knew there were annual international competitions where teams run their poker programs against each other and declare a winner at the end.
“There is this idea of working on the same problem as others. Because that really accelerates the progress,” Sandholm says. “Especially like with the poker and kidney exchanges, where people have the same exact problem to work on and then they really work on it in different research groups around the world. That really accelerates the process.”
The downside to competition is that you lose from time to time. But Fong says her husband “is very good at losing.”
“Tuomas does love to win,” she says. “But he also likes the process. And I’m not sure which is more important to him.”
Before the Libratus program beat the best humans at poker earlier this year, Sandholm’s prior program, called Claudico, failed to beat a team of humans in 2015.
“He thought of it much more positively” than just a loss, Fong says. “He was more wrapped up in what he could learn from it.”
Sandholm’s dedication to this process — interest, effort, failure, learn, repeat — is not confined to programming. A decade ago, he decided he wanted to learn how to do the forward loop in windsurfing.
Yes, in between everything else, Sandholm is a championship windsurfer.
In a forward loop, the windsurfer moves the board up off a wave, then does a full, forward flip while still on the board — and lands standing up. It’s an incredibly difficult maneuver if you live near a beach and can practice it every day on wavy surf; a monumentally more difficult one if you’re landlocked most of the time in Pittsburgh.
Sandholm was once one of the world’s best windsurfers; he finished 1st in Finland’s national championship in 1987, 5th that same year in the European championships, and 12th in the world championships. He probably would have gone to the 1988 Olympics with Finland’s windsurfing team, but the team’s leadership decided not to compete that year.
Yet even after he left behind competitive windsurfing, he still had the fervor to get better at the sport. So two decades later, after he decided that the forward loop was a trick he wanted to learn, he hired former world windsurfing champion Matt Pritchard to train him on his family’s annual, two-week trips to Maui.
“He was a little green when we started,” Pritchard says. “But now, he’s totally got his skills together.”
Not only did the pair work together in Maui, but Pritchard also had Sandholm do “dry land” training back home in a swimming pool — visualizing moving his body while diving off a board and using the boom of the windsurfing board in the pool. Fong would videotape some of the sessions and email the video to Pritchard who would reply with comments and recommendations.
“He’s so focused and motivated,” Pritchard says.
On June 3, 2013 — five years after he began pursuit of this trick — Sandholm finally completed a full loop and was able to land and surf away standing up. Completing the loop “was a single-minded focus” says Fong, who remembers breaking out the Champagne that night in celebration.
“It was extremely similar to his approach to winning the Libratus [poker] competition,” she says. “Some people told him he wouldn’t be able to do either. But he likes competition. He was not going to stop until he did it.”
And that trait just might benefit the planet some day.