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I worked in Amit's organization for over four years and it was great. He was brilliant technically both in terms of writing the main search algorithm that repla

by lacker 11y ago

I worked in Amit's organization for over four years and it was great. He was brilliant technically both in terms of writing the main search algorithm that replaced Sergey's janky code, and explaining tricky principles of designing search engines to other people as the search team massively grew. One conversation we had about when it made sense to take the square root of things, which I still recall which whiteboard it was on, in my noob-cubicle in building 43, was really the time when I realized, aha I get how to design search algorithms now. It was also always just a very fun, idealistic, and interesting team. And he was good at corporate politics and defended his minions well ;-) Oh also Amit clued me into the fact that Ardbeg is the best scotch. This is certainly a loss for Google, but the guy was there for 16 years, so it's probably just time for a change. I will cross my fingers hoping something cool comes next....

boomzilla 11y ago
Square root of relevance signals to "smooth" them out? I worked a bit on tuning search results, not at Google scale though and it's long time ago, but taking square root, or even logarithm of out of scale signals is a very common trick. Heck, even with the classic tf-idf signal, there are a bunch of heuristics like capping off tf, taking log of idf, penalizing doc length, etc. It's really a trial and error thing.
- lacker 11y ago
  Yeah exactly - both that square roots are good for smoothing but more so that a it's trial and error thing. When I started out after dropping out of grad school I was working on search algorithms and a bunch of my coworkers had a background in informational retrieval and I did not, and I was kind of thinking about it in the wrong way. I was thinking about it like it was a math puzzle and if I just thought really hard it would all make sense. So one day I was stumped in how to make this signal useful and Amit suggested, hey why don't you take the square root. I was like, why a square root, it doesn't make much sense, nothing is getting squared ever, and he went up to the whiteboard and just drew a square-root-ish-wiggle-arc-shape and said look you just want something that looks like this. Square root, log, whatever. I was like, oh... am I allowed to write code that doesn't make any sense? I thought I wasn't supposed to do that. And he was just like, well, just don't worry about it, you are overthinking it, you can take all the square roots you want, multiply by 2 if it helps, add 5, whatever, just make things work and we can make it make sense later. At that point I realized that real world software engineering was much different than research had been, and also that this was going to be way more fun.
  - jventura 11y ago
    When I started working in Information Retrieval this was something that I enjoyed right away. It was quite easy to come up with a metric that could give more value to some things instead of others.. A few years later I did a PhD in Information Retrieval doing the same kind of things, like it was an art and always exploring new metrics and ideas. I do miss those days, but it is hard to find remote work in this area (IR/NLP)..
    - yeukhon 11y ago
      I keep seeing Information Retrieval. How is it different from general search algorithm and are there grad programs famous for search? The only thing comes to mind is private information retrieval in security.
  - VikingCoder 11y ago
    > ...look you just want something that looks like this. Square root, log, whatever. ...And he was just like, well, just don't worry about it, you are overthinking it, you can take all the square roots you want, multiply by 2 if it helps, add 5, whatever, just make things work and we can make it make sense later. LOL. I can TOTALLY hear his voice in my head.
  - auggierose 11y ago
    I don't know much about search, but probably every software engineer should take some physics classes as well. Just to get used to that sort of reasoning, which is perfectly valid in a lot of circumstances.
    - nostrademons 11y ago
      I started out as a physics major. I remember the first time I had to do problem sets using the small-angle approximation or taking the first two terms of a Taylor series and dropping the rest. "Here's how you solve it: the angle of the pendulum from vertical is sin(x), which will always be small, so substitute x..." "Wait, you can't do that! sin(x) isn't equal to x." "For the purposes of this problem set it is..." I had a lot of trouble with this when I first started physics. I was used to thinking of mathematics as Platonic Truth, the eternal mysteries of the universe rendered absolute. But it's not - it's just a model, and it's a model that we use because in most cases it approximates reality pretty well. Contrary to the advice of many primary-school math teachers, sometimes it only matters whether you get the right answer rather than whether your reasoning makes any sense.
- elorant 11y ago
  For those of us not very accustomed with these ideas, are there any papers/resources to read?
  - nostrademons 11y ago
    Any course on information retrieval will have the basics. Here's an online textbook: http://nlp.stanford.edu/IR-book/ http://nlp.stanford.edu/IR-book/ A quick glance through it made me think there's a lot of tricks that are commonplace at Google but not mentioned in the text, but I'm not sure how many of them are proprietary, so I think it's safer for me not to mention them. TF-IDF, however, has a whole Wikipedia article about it: https://en.wikipedia.org/wiki/Tf%E2%80%93idf https://en.wikipedia.org/wiki/Tf%E2%80%93idf
    - elorant 11y ago
      Thanks!
tyingq 11y ago
>>the guy was there for 16 years, so it's probably just time for a change This would make sense to me if the announcement included what he was doing next. Often "retiring for personal reasons" is code for something they wouldn't want to put in a press release. Especially when the retiree is less than 50 years old.
- shawabawa3 11y ago
  Couldn't it just be "is a multimillionaire and doesn't feel like working full time anymore"? I know i'd be tempted in his position.
  - tyingq 11y ago
    It's possible. Not typical for the type of person that ascends to that level though. He and Matt were perhaps the two most well known names in that group to the outside public. Both with similar departures (or semi-departures).
- varelse 11y ago
  The scuttlebutt I heard on him is that he opposed using machine learning and artificial intelligence techniques for search, specifically deep neural networks. I can understand his opposition, Google search results have been monotonically declining in quality recently in my opinion. I wouldn't be surprised if this is a polite way to sweep him out of the way. It's pretty much a golden parachute if so. This is of course all speculation and hearsay based on what I heard about him a few months ago.
knughit 11y ago
> cubicle Ah, the heady carefree spendthrift days of the dot-com boom, when employers provided parts of walls!

by lacker 11y ago

boomzilla 11y ago

Square root of relevance signals to "smooth" them out? I worked a bit on tuning search results, not at Google scale though and it's long time ago, but taking square root, or even logarithm of out of scale signals is a very common trick. Heck, even with the classic tf-idf signal, there are a bunch of heuristics like capping off tf, taking log of idf, penalizing doc length, etc. It's really a trial and error thing.

lacker 11y ago
Yeah exactly - both that square roots are good for smoothing but more so that a it's trial and error thing. When I started out after dropping out of grad school I was working on search algorithms and a bunch of my coworkers had a background in informational retrieval and I did not, and I was kind of thinking about it in the wrong way. I was thinking about it like it was a math puzzle and if I just thought really hard it would all make sense. So one day I was stumped in how to make this signal useful and Amit suggested, hey why don't you take the square root. I was like, why a square root, it doesn't make much sense, nothing is getting squared ever, and he went up to the whiteboard and just drew a square-root-ish-wiggle-arc-shape and said look you just want something that looks like this. Square root, log, whatever. I was like, oh... am I allowed to write code that doesn't make any sense? I thought I wasn't supposed to do that. And he was just like, well, just don't worry about it, you are overthinking it, you can take all the square roots you want, multiply by 2 if it helps, add 5, whatever, just make things work and we can make it make sense later. At that point I realized that real world software engineering was much different than research had been, and also that this was going to be way more fun.
- jventura 11y ago
  When I started working in Information Retrieval this was something that I enjoyed right away. It was quite easy to come up with a metric that could give more value to some things instead of others.. A few years later I did a PhD in Information Retrieval doing the same kind of things, like it was an art and always exploring new metrics and ideas. I do miss those days, but it is hard to find remote work in this area (IR/NLP)..
  - yeukhon 11y ago
    I keep seeing Information Retrieval. How is it different from general search algorithm and are there grad programs famous for search? The only thing comes to mind is private information retrieval in security.
- VikingCoder 11y ago
  > ...look you just want something that looks like this. Square root, log, whatever. ...And he was just like, well, just don't worry about it, you are overthinking it, you can take all the square roots you want, multiply by 2 if it helps, add 5, whatever, just make things work and we can make it make sense later. LOL. I can TOTALLY hear his voice in my head.
- auggierose 11y ago
  I don't know much about search, but probably every software engineer should take some physics classes as well. Just to get used to that sort of reasoning, which is perfectly valid in a lot of circumstances.
  - nostrademons 11y ago
    I started out as a physics major. I remember the first time I had to do problem sets using the small-angle approximation or taking the first two terms of a Taylor series and dropping the rest. "Here's how you solve it: the angle of the pendulum from vertical is sin(x), which will always be small, so substitute x..." "Wait, you can't do that! sin(x) isn't equal to x." "For the purposes of this problem set it is..." I had a lot of trouble with this when I first started physics. I was used to thinking of mathematics as Platonic Truth, the eternal mysteries of the universe rendered absolute. But it's not - it's just a model, and it's a model that we use because in most cases it approximates reality pretty well. Contrary to the advice of many primary-school math teachers, sometimes it only matters whether you get the right answer rather than whether your reasoning makes any sense.
elorant 11y ago
For those of us not very accustomed with these ideas, are there any papers/resources to read?
- nostrademons 11y ago
  Any course on information retrieval will have the basics. Here's an online textbook: http://nlp.stanford.edu/IR-book/ http://nlp.stanford.edu/IR-book/ A quick glance through it made me think there's a lot of tricks that are commonplace at Google but not mentioned in the text, but I'm not sure how many of them are proprietary, so I think it's safer for me not to mention them. TF-IDF, however, has a whole Wikipedia article about it: https://en.wikipedia.org/wiki/Tf%E2%80%93idf https://en.wikipedia.org/wiki/Tf%E2%80%93idf
  - elorant 11y ago
    Thanks!

tyingq 11y ago

>>the guy was there for 16 years, so it's probably just time for a change This would make sense to me if the announcement included what he was doing next. Often "retiring for personal reasons" is code for something they wouldn't want to put in a press release. Especially when the retiree is less than 50 years old.

shawabawa3 11y ago
Couldn't it just be "is a multimillionaire and doesn't feel like working full time anymore"? I know i'd be tempted in his position.
- tyingq 11y ago
  It's possible. Not typical for the type of person that ascends to that level though. He and Matt were perhaps the two most well known names in that group to the outside public. Both with similar departures (or semi-departures).
varelse 11y ago
The scuttlebutt I heard on him is that he opposed using machine learning and artificial intelligence techniques for search, specifically deep neural networks. I can understand his opposition, Google search results have been monotonically declining in quality recently in my opinion. I wouldn't be surprised if this is a polite way to sweep him out of the way. It's pretty much a golden parachute if so. This is of course all speculation and hearsay based on what I heard about him a few months ago.

knughit 11y ago

> cubicle Ah, the heady carefree spendthrift days of the dot-com boom, when employers provided parts of walls!