skysight-inc/HackerNews huggingface dataset:
So here's a typical problem that I'd have in an HPC application. I'd have some space, represented by some 3D structure (maybe an array, or even an object-based particle system). I need to do some computation over this space -- often using some type of stencil, so in order to compute the value at <x,y,z> I need values of coordinates some distance from x,y,z.

The part that often ends up being tricky is the fact that I need to send data from processor A to processor B. And I want to send as little data as possible. So one of the first sources of bugs is that when I do my gather-scatter I make a mistake mapping a value to a coordinate. In shared-memory you never have to do this mapping back and forth, so its not an issue.

Next issue is related to the fact that I don't want to ever block waiting for data. There are a variety of models for handling this. I can do a non-blocking receive, and do some work waiting for the data to arrive. This is often another source bugs as people will often do work that depends on the new data, but they chug along without it. Add the new data when they get it, and alas their computation is already hosed.

And the last common error in this case is handing the data off to the wrong object (or processor) or being confused as to which data you're receiving at any given point in time.

Now all of these can be handled by simply being careful, and using some good programming practices. But they are just simple, if not grossly naive, examples of issues you have with traditional message passing that don't exist in shared memory.
Yes, yes indeed. Looking at it like that, it is great a response, but there's still a problem...

Given the rather adversarial nature of the technical interview setting, there's pretty much zero probability you'd actually get that answer from him.

This presents an interesting dilemma.
Community-developed Pivot Power strip now available to order
> The probability that they are both heads is 1/3.

The probability they are both heads is 1/2.

You're trying to formulate this as ....

P(head AND head | one is a head) =
P(head AND head) / P(one is a head) =
1/4 * 4/3 = 4/12 = 1/3

But this is wrong ... you know that you have a head ... which makes ...

P(one is a head) = 1 && P(head_a AND head_b) = P(head_a) = P(head_b)

1/3 would be the probability only on the first try (instead of stopping when you've got a head).
more explanation please?
I always thought that a "share this" link was a cheap way websites slightly increase their virality. Does this really have a legit use?
I read Naggum's posts regularly on comp.lang.lisp for years. They always generated much more heat than light. He was entertaining but terribly misguided. I don't miss him.

I do kind of miss Xah Lee though.
I'd imagine that one with more karma built into the system would have more <ahem> staying power.

I think a dating service built on top of Facetime (again, with karma) would be pretty neat. Sort of like virtual speed-dating. Meet random people that meet your "requirements" and get to know them. Upsell: Give out the app for free, but limit connection times and all connections are anonymous (but reporting is not). Paid app lets you maintain an address book and unrestricted connection times.

Alternatively, those with the "free" version of the app are branded as such (i.e., your connecting partner is told that you are a cheapskate), providing social pressure to show that you're willing to spend money to meet interesting people.

Policing the system is probably the hardest part - setting up the social conditions such that fraudulent claims are kept to a minimum (and require little to no input from the service owner) is a challenging task.
Wow, I am blown away by the concept of community-developed hardware. The power strip isn't bad, either :-)
Just for a year.
To begin with, yes. It also depends on how heavily I denormalize the data for recall. It could be many times that down the road. I'm not looking to implement something heavily distributed right now, but I know that day is coming with my datasets and I want to ensure I know what needs to be built when the time comes.
EDIT: Has anyone else had OK experiences with on-the-spot programming as they were interviewed? </edit>

I don’t get all the people saying that most people can’t code under the pressure of an interview. What’s the big deal? It’s one function. I have certainly been asked technical questions in interviews, including to write code on a whiteboard, and it’s no big deal — I have missed a bracket or two, or been slightly off, but if it’s 95% right that’s good enough for the interviewer.

I’m not Mr. Cool, either. Finals, deadlines, and papers all really stressed me out in school (mere months ago). I can just code alright and I understand the tech.

I just don’t get it.

I also don’t understand what the alternative is: just take people at their word they are great programmers?
"Education is what is left after all that has been learnt is forgotten." -- James Bryant Conant

I've always liked that one :-)
Programmable Matter
For experienced database engineers, $125k isn't an impressive number, and it's the highest salary listed at rethink -- meaning that you're unlikely to get that number without being judged so "senior" by the rest of the company that you merit the highest salary possible.

I've always thought that their choice to post those salary numbers was a bit foolish. Far better to negotiate a low-ball offer for an experienced candidate after selling them on your company during the interview, than to have them avoid interviewing at all because your salary ranges are fixed and low for the industry.
First of all, no worries -- you are more than entitled to your own opinion. I agree in many respects, maybe I am naive to think that the company should proactively manage some aspects to ensure the affiliates are ethical and upstanding "referrers."

At some point there must either be:
(1) such an awesome product I will shout it from the rooftops; or
(2) big enough incentive to tell people to try it (still should be a good product)

Dropbox did such a great job because they managed to create the 2nd scenario without a cash outlay.

Appreciate the discussion! Good luck with your programs, whatever you decide to do
Psychic Octopus picks Germany to beat Argentina
Chatroulette is far from dead, it's still a top 3000 website (or thereabouts), which makes it larger than 99.99% of all the websites in the world. Not too shabby, and many people calling themselves 'entrepreneurs' and 'start-up' people would give an arm and a leg to be in that position.

Chatroulette suffers from the exact same problem that ww.com suffers from, which is that it takes only a very small percentage of 'jerks' (how appropriate) to spoil it for the rest. On ww.com I've managed to somewhat mitigate the problem by making labeling of your content mandatory.

I've spent an awful lot of time on trying to automate the detection of inappropriate content but there are many reasons why that is a lot harder than it seems.

A chatroulette based on a 'real-names' log-in procedure that would then connect users anonymously would be one possible way to combat the problem.
I don't think they will have a problem with my irrelevant side project either, but I like to cover all of my bases like you said.

I am a full-time salaried employee (not contract-based) and I am free to quit at any time/they can fire me at any time. So I guess that is at-will, right?
kbd+ is a column store (analytic database) and does not partition horizontally. The two things they have in common is that they are both in memory (and kdb+ not necessarily) and support SQL as a query language (kdb+ only supports SQL like stuff). kbd+ does not emphasize stored procedures as a means of bringing multiple queries and arbitrary logic to the data. Nor does it need to since it doesn't partition.
This article could very well be true, but I've become highly suspicious of these apple rumor articles over the years. Especially ones that randomly pop up after a 4.5% AAPL stock dip. The cynic inside me is telling me that someone's starting a rumor so they can dump some stock on its way down...
See: http://news.ycombinator.com/item?id=1452636

The author's last comment was:

> Hey Mike, I'll get in contact with you shortly once I pull some logs. We've been analyzing the data and it seems that where we lose data coincides with some system reboots, we had a few problems with replication a few weeks ago, and had it disabled, so that's likely why we are seeing loss.

( http://news.ycombinator.com/item?id=1453133 )
Thanks Kara Wilson, VP of Collaborative Solutions Marketing. As a corporate division manager myself, you identified the very cornerstones we plan to implement in Q3 - synergy, paradigm shift, and corporate MBA tech speak. Getting signed Cius purchase approval from corporate now.
Depends on complexity. Would you like to write a 4-hour test assignment that boils down to partial sort of dependency graph (true story)? Oh and no pseudocode, it has to compile and run.
I recently read an article in which they say one can solve problems in their dreams [1]. I could swear it has happened to me at least a couple times.

[1] http://www.msnbc.msn.com/id/37926551/ns/health-behavior/
That guy has no clue how to use a non-relational DB (he even admits it) and he uses a DB that is wrong for his task and wonders why it's so hard.

The only point he makes is that the APIs for non-relational DBs are much too simple and limited, so you end up building lots of code on top to do the most trivial things.

What we really need is a way to generate indexes or materialized views on these DBs in a standardized way (see CouchDB, for an example).
Last posted about a month ago: http://news.ycombinator.com/item?id=1345008
Verizon iPhone coming in January?
Coincidentally, all of these "legal media" fields are seeing decreases.

The media companies need to start competing with Bittorrent on actual quality of service, like Apple did. If the illegal route is that much more pleasant than the legit way, something is wrong with your business.
Amazon.com Hit by Performance Problems
He has no clue how to use a relational DB either (he even admits it). How and why is this on the homepage?
4 Rules for Split-Testing before Product/Market Fit
The scary thing is that I once knew what condition variable is, but forgot.

Easy to say it here, but would be really poor answer at an interview :)
It's been fun :-)

> If I toss two coins until at least one shows a Head, what's the probability that both are Heads?

I answered in my last reply ...

P(head_a AND head_b | head_b) = 1/3

The problem is that head_a and head_b are independent events, and that P(head_a) = 1 (you made sure of that).

P(head_a AND head_b | head_a) =
P(head_a AND head_b) / P(head_a) =
P(head_a AND head_b) =
P(head_a) = 1/2

QED :)
It is a misrepresentation because doctors aren't saying "that's impossible" they're saying "what you claim your product does is false because for your implementation to work would require impossible reactions".

You've misrepresented their position of debunking junk medicine by claiming their position is that the end result is impossible.

And you imply (by omission basically) that the people in Steps 1 and 4 are from the same field (junk medicine) which is never the case. You want to attribute this general fuzzy-wuzzy idea concept to junk medicine to validate junk medicine as a whole.

However, of course results claimed by junk medicine will be replicated by real medicine later. Junk medicine doesn't have to work. Junk medicine has had baldness cures and impotency cures since forever. Real medicine now actually does have stuff to correct baldness and impotency. That does not mean that junk medicine had anything to do with solving the problems. The best that could be said for junk medicine is that it articulates problems.
Tesla Motors shares surge in 1st day of trading
are there actually people who are trying to put some fault on redfin for hiring a spy?

i mean, if the russian government trains and backs a spy, and they're not even able to land a job working as someone who shows real estate on a contract basis, i don't know how they'd expect to be able to pull meaningful governmental information.
The Django Framework's Killer Feature for Java Developers
> Suggesting there is no difference between a Key Value store and an SQL database capable of ad hock queries, Transactions, and Joins is ridiculous.

My intent was to make the claim that VoltDB is a feature subset of a relational database and is overhyped in the same lines that many NoSQL servers are. It's just a different subset of features than the key/value store servers.

My point boils down to VoltDB is merely another option if you have corners you can cut from the normal relational database model.

I probably could have been more clear in stating that. Bringing mongodb into the discussion muddied things.
How is github expensive if github is FREE!?

All you would have to do is open source your projects, and pay a big fat $0 per month. Just .gitignore your sensitive data files like database credentials, api keys, etc. If you are using something like capistrano to deploy, all you would have to do is upload these files to your server, then hook a function onto the deploy action that symlinks the sensitive files back into place.

You can't possibly complain about FREE now can you?

P.S. I love github (and pay 7 big ones a month even though I don't really have a job and am running out of money like its nobody's business)
A view from an insider that spent a decade there: http://www.metafilter.com/93279/Window-to-Dell-Decline#31590...
I have no idea what problem you think you're solving, but it's not the one I posed. I never said a specific coin was heads, I just said at least one of them was heads.

Given that I make money on these sorts of questions (doing it for real in a semi-military context where it's important to be right, and you get tested against reality) I feel pretty confident that I know what I'm talking about. You're clearly talking about something completely different, and I really don't understand what you're saying.

And that's the last I'll say.
The approach described is ridiculous, and I'm glad to see that so many others here on HN see it the same.
While I like reading informative articles about hackers mastering their tools, this article doesn't have a lot of general purpose information, or mastery of tools.

A follow up article about the query architecture in all three implementations could be interesting: how he failed with a relational DB, how he failed with a key/value DB, how he succeeded with a relational DB. An article like that could have an interesting story arc and may include information applicable to other developers.
I stopped watching about 20 seconds into the video. Did she even turn the thing on?
Telsa stock rises to $24 - Gamblers, believers unite
Fast-tracking: Alternatives to college
YES! Oh man, I want to thank you for saying that.

I would love to find a co-founder. I've bootstrapped a successful business, it's going quite well, and I've been doing it for 2.5 years now. I've simply refused to give up at every step of the way -- even though I've often wanted to. And if I have my way, this business is going to get quite big.

But, I'm not running the sort of thing that YC would be interested in, and my sporadic efforts locally to drum up support have accomplished little.
Some more of Erik Naggum's "wisdom." He was brilliant, but he could also be astonishingly cruel.

I'm overjoyed that I actually hurt your feelings. I wish I could hurt your feelings so much you would commit suicide. sadly, this has failed, and now the world has to live with an amoral creep who considers himself above ethics and reproach. you are clearly a psychotic monster, beset with hatred and malice towards everything that hurts you, and you're so out of touch with reality to begin with that your fantasy world is taking over, and hence it is in fact impossible to hurt you, any more than you constantly hurt yourself. this is also why you have to imagine what my day is like, and post your literally insane imagination. any remnant of sanity would have held you back from such levels of psychotic behavior.

you should consult a psychiatric ward and have yourself committed before you actually kill someone in your deranged, psychotic state, filled as you are with hatred and malice towards people who didn't stop hurting you when you screamed "please don't hurt me" to yourself, only.

the only thing I regret is that I didn't see your fantastic stupidity as a result of your shattered psychology -- it's fairly uncommon to be so fucking retarded because of a psychological problem, but clearly, you have been immensely stupid all your life, and now that I come and hurt your stupid feelings, so you turn on me like a vicious and mad dog -- and that's exactly what you are to me: a mad dog in need of a bullet through his sick brain before he actually manages to hurt someone or himself.

do the world a huge favor and commit suicide tonight.

on the surface, it was an attack on someone who disagreed with him, but in hindsight, I think it was actually a self critique.
YouTube's thoughts on Flash and the video tag
If I were an interviewer, here's what I'd be looking for:

1. You hear "reverse a linked list", you maybe ask some clarifying questions (expected efficiency, in-place or a new list, etc.).

2. You start drawing boxes with arrows on the whiteboard.

I've never been able to come up with any algorithm for a linked list without drawing a bunch of arrows and staring at them. And while lots of people might be too stressed out to come up with the algorithm, any programmer who has even a little experience with lists should know to start with that.

In other words, if you have any experience with this kind of stuff, it shows up pretty quickly by what you do/what you say.
Correct. Contracted work for full-time employees isn't common, but I thought I'd ask,
So why don't you do it any more?
Everything in moderation - if you took 40,000 aspirin's in 9 years you'd see some strange effects.

And MDMA is absolutely incredible; I recommended everyone tries it just once. Had some of the best nights of my life on it - completely untouchable experiences.
I'm 24 and I've been coding C++ for the past 4 years, it was my first language and remains the one I use the most, though I've used Ruby professionally most recently, I'm trying to get a C++ gamedev job now.

So its not just the older crowd, it very much depends on what you're trying to do I think.
Same here about condition variables and preemptive vs cooperative multitasking. I know the concepts, but not the names. I think mabye C programmers have to deal with that stuff more often? In most other environments, the need doesn't arise that often. Many are designed especially to avoid that need (ie node.js, Erlang),
Moved a personal blog from MySQL to TokyoCabinet to Postgres? Why?

He writes:

"I have no idea how to use a key/value store database properly."

You don't need a database, or object-store or anything fancy to get decent performance for a personal blog. I use Chronicle and it spits out flat files; lighttpd uses sendfile(2) and everything is fast. FWIW, his blog software is one he wrote in Clojure:

http://github.com/briancarper/cow-blog/tree/0.2.0

For read-intensive applications, Sqlite3 would do just well.

This write-up should not influence anyone with respect to the (de)merits of MySQL, TokyoCabinet or Postgres.
Again, Glassdoor.com doesn't seem to have a lot of data showing that database engineer salaries above $125K are widespread. I'm interested in any evidence supporting that view (relates to some other conversations I've had recently).
Have you looked into CMake to alleviate your compilation woes?

I recently started using it and its been very useful so far.
How exactly does this work? I dug around the website a bit but couldn't get a clear picture of the basic architecture in my head.
Chatroulette could allow users to flag the perverts, and also give users the ability to request "Please don't show me perverts". I don't see this as a difficult problem for them to solve if they wanted to.
I wondered that too.

My first thought was to build it up again from new conses, as you would in lisp. But then spotted a neat in-place way to do it too.

Found I absolutely had to draw a few scribbly diagrams first though.
Consistent error handling is needed if you are returning 0 for success and -1 for failure. Or was it 1 for success and 0 for failure? But there's nothing wrong with a type signature that precisely describes what you can get back. Only argument I'd have with Either is it's not obvious which is the error (although left is the convention and baked into the monad), although in practice you'll be returning "Either ParseError ParseTree" which makes it rather obvious. Also, do-notation over the Maybe monad is just perfect for simple error handling, but sometimes you need to return more than None. Happily, you can switch to Either without changing a great deal. But you can't mix them easily, and that is a suckful thing about monads indeed.
I know a few people who did very well despite the fact that they were college drop-outs. But what may work for programmers does not work for other people. For starters, writing code is a kind of work in which one's productivity and competence can be easily measured. If you have a lot of projects under your belt, you are essentially demonstrating that you can do stuff, and that is worth more than a diploma itself.

The dangerous thought is assuming that what works for programmers can work for other people. If you want to be a lawyer or a medical doctor, what projects can you have under your belt that demonstrate "can-do"? None?! Promoting the idea that an undergraduate degree is not valuable is an extremely irresponsible thing to do. I know that HN is a hacker community full of can-do over-achievers, but the rest of the world isn't like that... and perhaps it shouldn't be like that.
I disagree, at least based on my personal experience. I suppose I've interviewed at a dozen or so companies over the years and gotten job offers from all but 1. There's almost always something I get asked during an interview where I just honestly say, "You know, I'm not really all that familiar with that" or "I'm pretty rusty on that area at the moment". It's a better answer than trying to BS something.
That sounds quite rough, but that’s not FizzBuzz or the kind of function described in the article. Good point, though.
It depends on what you want to do. Me, I really like cryptography, for now; I accepted a one-year contract at sub-market rates (i.e. the usual PhD salary) to work in that field.

There are, perhaps, five or six employers in the Netherlands who employ crypto researchers, and these people didn't actually have an opening. I admit that it's not the best job from a business perspective (little job security, highly specialized knowledge, sub-market salary) but I really like it.

(Of course, a "Django guru" or "C++ wizard" has a lot more options and might want to use a different strategy...)
This is what I understood: "Is it possible to grow an audience organically on the web and reach ramen profitability within a year or so"

My answer: It is not likely to happen. Getting traction is the single hardest problem for startups that are neither technically challenging, nor game changing. By organic audience I mean users acquired through WOM, and press coverage.

You can spam (just like Facebook and Myspace did) and get your product in front of more people and hope they click SIGN UP.

I know most people find sending an unsolicited email as a huge ethical issue, but quite frankly a spam email sent to the potentially right user can be helpful to both her and your business.