Tuesday, January 19, 2010

Machine Learning in One Sentence

Posted by Danny Tarlow
We've all had this experience: you're out at some party or social event, doing your best to blend in and have a good time. Inevitably, though, somebody wants to talk to you. One thing leads to another, and it happens: they ask, "so... what do you do?"

My default answer is
  • "I'm a Ph.D. student in Computer Science." (optional addition: "I do something called 'machine learning' ")
It's not the most exciting answer in the world, but it's surprisingly effective--from here, it's fairly easy to read whether the person opposite me just perked up at the idea of finding a like-soul or whether their eyes just glazed over as they stumble around looking for the nearest exit. But seriously, it gives somebody the opportunity to press further, but usually it provides a nice opening to change the subject tactfully--it's an improvement over the more extreme tactics that may leave somebody thinking I have some deep dark secret or that I'm a criminal, etc.

This leads me to wonder, though. What, then, is the most exciting answer in the world for a PhD student in machine learning to give? A few rules:
  1. One sentence limit.
  2. It has to be more-or-less true.
  3. (this is the hard one) It needs to be a conversation starter rather than a conversation ender. So while "you don't want to know" satisfies (2), it is disallowed by (3).
I can think of a few not-terribly-creative possibilities:
  1. "I teach computers how to think."
  2. (serious face, matter-of-fact tone) "I develop algorithms for MAP inference in graphical models, typically looking at classes of energy functions where standard techniques like quadratic pseudo boolean optimization or max-product belief propagation are inefficient or don't work well." (Update: this one is meant to be a joke, for the record)
  3. "I pretend my computer is a baby, and I try to teach it about the world."
  4. "I design parts of robot brains."
Help me out here. Do you have better ideas? No need to be a PhD to contribute. As a reward, I promise to take the best suggestion, try it out "in the wild", and report back.

Sunday, January 17, 2010

Latex on Blogger

Posted by Danny Tarlow
I am playing around with the (very simple) instructions provided here for getting LaTeX ($\LaTeX$) to work on Blogger: http://watchmath.com/vlog/?p=1244

This is a test:
\[ E(\mathbf{x}) = \sum_{i \in \mathcal{V}} \theta_i(x_i) + \sum_{ij \in \mathcal{E}} \theta_{ij}(x_i, x_j) \]

Update: seems to work properly on the post-only page, but not on the blog home page. More to come...

Update 2: I think I was wrong. It looks like there's a bit of randomness to when it works and when it doesn't. I was fooled into thinking it was due to which page I was on. Also, for further reading, Terence Tao has some good discussion--including some of the shortcomings--regarding displaying math on the web.

Wednesday, January 13, 2010


Posted by Danny Tarlow
I'm in shock reading the sad and confusing news about former Toronto (and more recently, NYU) professor, Sam Roweis.

The Toronto Machine Learning group has been missing Sam's presence at our meetings and around the lab for a while now; he was on sabbatical at Google and more recently took a professorship at NYU. I have many memories from my first couple years in Toronto, though. You could always count on Sam to spark an interesting conversation after a seminar or tea talk by asking the penetrating question that cut straight to the heart of the issue. I learned a lot about how to critically think about new ideas by watching Sam in action.

As a teacher, Sam was phenomenal. He had a unique ability to present complex material in a well-motivated, clear way. My favorite part of his lectures were his "street fighting tips" where he'd teach us the tips and tricks that it takes to translate the "book form" of an idea into a program or algorithm that actually works. This ability to connect the elegant theoretical understanding to the practical understanding is something I will always admire.

Finally, Sam was just a really good guy. At one of the earlier conferences that I went to, I knew very few people. Sam recognized this and made the effort on several occasions to come talk to me, explaining parts of talks that I didn't understand, giving his thoughts on some poster, and even going so far as to find other professors to introduce me to. There were so many people there more deserving of his attention, but you'd never have known it from my perspective.

The world is unquestionably worse off without such a brilliant researcher, teacher, and all-round great guy. I think I speak for an enormous number of people when I say we'll miss him greatly.

Update: Posts by people who knew him better than I did: Fernando Pereira, John Langford, Maneesh Sahani, Jennifer Linden, and many others.

Tuesday, January 12, 2010

Google's China policy

Posted by Danny Tarlow
I know I'm just repeating the news that is now several hours old, but I find this one very interesting: http://googleblog.blogspot.com/2010/01/new-approach-to-china.html