skysight-inc/HackerNews huggingface dataset:
Here's another piece of advice that covers a lot more than matrix inversion: don't solve math problems yourself in code if you can in any way avoid it.

Use a library instead, and use the most specific methods that are available: if there are specialized routines to solve Ax=b, use them, don't use the matrix inversion methods (which are probably also there), or even the LU decomposition ones, even if Real Math tells you that the result is equivalent - in numerical computation, mathematical equivalence is an entirely different entity than what "real" mathematicians concern themselves with.

Seriously. I don't care if you're a math PhD, I don't even care if you know a decent amount about numerical methods. Whatever code you're going to put together to do the job will be inferior to what a mature library can do, simply because the library has been put through many iterations and has had a lot more time to get patched up to handle all those special cases (usually related to finite precision or discretization) that Real Math doesn't have to worry about. And it will probably be vastly more optimized than anything you'll put together, because it's spent years of heavy use in some critical research environments.

The only time you should be writing your own math code (beyond simple arithmetic) is if no mature libraries are available to you. In which case you should allocate at the very least twice the amount of time it will take to research and implement the methods, and probably a lot more, because you're going to have a lot of fiddling to do.
A related note: this is one reason why publishers like ebooks (obviously there are disadvantages for them, too). It's also why I don't like ebooks.

I guess I'm a cheapskate. Well over 50% of my personal book consumption comes from used or library books. Over 90% of my family's books come from such sources as well. I would absolutely love to dive into ebooks, if only to massively reduce the physical volume said books take.

But I can't, not without either severely curtailing our family's reading or increasing our spending by, probably, a thousandfold.
Go ahead and try it out. I've only solved 87 problems, but I enjoyed it very much. My experience was that many problems were very deceptive. At first you think, it is really easy, and after awhile it becomes evident that the problem is much harder than initially thought. I appreciated that every problem seems to teach you something new, even if the problem seems very similar to a previous one, there is usually a twist.
[added] one example: script.aculo.us
Criteria for Selecting Web Startup Lawyers
It's in the works. If all goes well, hopefully the CoffeeScript-in-CoffeeScript compiler will become the mainline:

http://github.com/creationix/coffeepot

Here's a link to Tim's alpha, which is able to parse a limited subset of CoffeeScript (we need to figure out what to do with left-recursive rules):

http://static.creationix.com/coffeepot/test/browser.html
By Max Chafkin |	Feb 1, 2010

Wow, news really travels fast on this site! Can anyone find the Apple Tablet announcement somewhere on the future-web? I'd love to know what it looks like.
Is Tug of War Between VC and M&A New? Or Even Real?
Too Much Sitting Shortens Lives, Study Suggests
So the problem [is] old users posting the same comments.

Interesting hypothesis.

experiment to try to refocus the discussions

Expound?
I seriously doubt good reviews would just disappear. The reviewer would complain. I'm a Yelp Elite in my city and I'd scream murder if any of my reviews disappeared.
Of course, one would want to look at this study in light of Peter Norvig's advice

http://norvig.com/experiment-design.html

on interpreting research studies.
You can solve amazingly large problems with a sparse matrix with out understanding what you are doing, as long as you use direct (factorization) methods. If you type A\b with some gigantic sparse A, matlab will apply reordering heuristics that often just work, and are actually incredibly hard to improve upon by manual fiddling. When you get to really, really big problems, you need to use iterative methods (like conjugate gradient), and for those you have to have a very firm understanding of everything. The gap between direct and indirect methods is huge.
7 days a week, first thing in the morning and multiple times during the day. It´s addictive.

Sometimes I even get to HN for inspiration when stuck in a project/problem.
I agree, and you also risk alienating 50% of the population by tacking a big "no girls allowed" sign on the Android clubhouse.

Also, yes, while Android and Droid are not synonymous, I think for most American consumers the brands share quite a bit of overlap.
Am I right in reading the graph, that when HN started, there were several thousand users?
Is Technical Debt a Technical Issue?
They may show your review to you but not others.
Speed is not the only measurement, accuracy can also be a problem.
I'll add here that more people should date comments in code! Don't know how many of you are collaborating on projects, but It's a personal pet peeve of mine to see something like:

// Updated for the new login system

...which of course has other problems too, but it's really annoying to try to figure things out when comments are out of date.
Biggest challenges for American intelligence? The way the brain works
"that said, it's also a common mistake of free marketers to think of a work disincentive as inherently bad"

The article points to work disincentives created as unintended consequences of (a combination of) other apparently unrelated policies. Are you suggesting that since work disincentives are not bad, its okay for them to be created this way?
Crowdsourcing Work Meetup January 20 in SF
IIRC there were around 1500 uniques the first day.
I've only been on one side of the equation. :)
You Are Unlikely To Prosper: P2P Lending much riskier than you think
I'm on the same schedule.
Sarunvalodas stils / Referāts / Literatūra
Random association, but my first experience of this was comic books. When I was younger, I remember that the date on the book was always way ahead of when I bought it.

I bet this goes back to some weird print/magazine marketing thing: more current = more better.
Canadian Citations -- Breaking News on canpages.ca
I'm not following some of this. It's true that the marginal benefits of salary changes for wealthy[1] parents with children in private (US) colleges who also are applying for a mortgage payment reduction on homes they can't afford is very small. And for these folks, it may be very tempting to take a part time position[2] instead of working harder.

But needless to say, that's a rather small population. The article is cherry picking this small population[3] of kinda-sorta-unfortunates (they're still making $120k a year!) and using it to argue against a bunch of government programs that provide real benefits to people with a fraction of their income.

Could things be tuned better? Yeah. Benefits programs are filled with this kind of unintended side effect. But to write this kind of blanket argument cautioning against them seems awfully partisan to me. It's a fairly typical right-wing Forbes editorial in journalism clothing.

[1] $120k per year is in the top 10th percentile or thereabouts -- it's at the very edge of what most people would consider "middle class".

[2] NOT simply a lower paying one, as the article implies. A lower paying position is still full time work, after all. The contention that making less is "bad for the economy" isn't really sound. Downward wage pressure in high-paying jobs is a good thing for the export economy and a good thing for profits (companies are paying historically high fractions to their most highly compensated employees).

[3] That is: gate the income to a small range just big enough to be affected by the loss of financial and mortgage aid, but not so big that it dillutes back to the overall tax rate of ~38%. Then pick out only the people who actually need that tuition and mortgage aid: parents with both underwater mortgages and privately-school children in the right 4-year age range. If this isn't cooking the books, I don't know what qualifies.
Firefox 3.6 Receives a Second Release Candidate
Seems like not a lot has changed since I went to school. It seems like universities cater for the very poor and the very rich. The middle class is left to carry the brunt of education costs.

Also, welfare isn't indefinite. Most states require you to take a job, any job, or they reduce your benefits. This is the legislation that came out of the Clinton era (when Gingrich was claiming welfare queens were living it up by having 7-10 kids). I'm glad that I'm still young and healthy. It's one thing to drop COBRA in your 20s, quite another to do it in your 40s.
Is this the case of the metric system vs English system? IMHO, the metric system is superior, but it is too expensive to change in the US. Or driving on the left or driving on the right. In this case both are similar but it is desirable to have a worldwide standard.
Did you wait a while before creating an account?

If you did, then you can ignore the rest of my comment.

If not, you could have joined during one of HN's "popularity peaks" when it was mentioned on another popular website, creating a wave of new users. Those peaks always seem to correspond with a rush of Techcrunch (and similar) articles.
For a more academic-economics-oriented article on the same theme by the same authors, see http://www.utdallas.edu/~liebowit/keys1.html , from _Journal of Law and Economics_.

Incidentally, I would be very interested in a pointer to a comparably serious/academic rebuttal of Fable of the Keys. It has been a very long time since Fable of the Keys was published, and it has been a long time since I last tuned into the controversy, and at that time my understanding was that a rebuttal had long been promised but never produced.
I've noticed that my comments have been typically getting less points than they used to. What I've noticed is that when I don't get as much positive reinforcement (points) as I used to, I'm less inclined to take 30 minutes and writing and editing a thoughtful comment. It's a downward cycle.
I'd like to know when you think an increased economic output is a bad thing? The only argument I can see for that is to protect people from themselves, but then again, I really don't like it when the government tries to mettle with people who are doing no outside harm.

I'd rather have a large supply side driving costs down and improving my quality of life than otherwise.
Most acquisitions fail. The founders get distracted or leave. Key employees get frustrated. And so on.
Right - it's the sitting. It couldn't possibly be that the kind of person that watches hours upon hours of TV each day just might have other unhealthy habits...
> How did a middle-class single mom wind up with a 79% marginal tax rate? At $120,000 she would pay $16,500 a year more in federal and state taxes, wouldn't qualify for the five-year $12,000-a-year cut in her mortgage payments she's applying for and would be eligible for $19,000 a year less in need-based college financial aid.

It's a bit disingenuous to include lack of financial aid as a "tax" on her income .I assume the college is private? Regardless, she's not paying another $19,000 to the government, just not getting it in aid from another institution.

Without the financial aid "tax", her marginal tax rate is 47.5% for that $60,000. Not great, but not absurdly high considering it includes federal and state taxes (which in NY are quite high).

> Work isn't the only middle-class virtue that is getting punished. The system penalizes savings, too--not just through taxes, but also through programs that reward debtors, the profligate and college families that show up at the financial aid office with empty pockets. Yet another series of tax and benefit rules penalizes marriage.

As a non-homeowner and big saver, I agree :)

I think the real issue here is that tax code is far too complex, filled with favors and subsidies left and right that complicate matters (think spaghetti code).
It probably just means that the article will be in the Feb 1 issue.

Skewed dates might be more accurate, but they'd also be more confusing in a lot of use cases than simply using the print date everywhere.
My mother didn't bother working at all when she lost her job and I was in college, for exactly this reason.
It's not specific to universities. Go take a look at a chart of middle class salaries over the last 30 years, adjusted for inflation. Looks awfully flat, right?
That sounds like the broken window fallacy to me.
The article seems to assume that social factors like product prevalence should have no bearing on the actual ultimate economic benefits of the dominant player, and that's silly, in my opinion.

We've only seen it more and more often; something may be technically better, but there's more than technical consideration in choosing a product, and if the newer product can't overcome the social inertia associated with the old product, then it doesn't offer a net benefit.

People choose PHP because there is an abundance of PHP programmers and businessmen want to stiff people on pay more than they want a good interpreter running their software.

People choose Windows because the system is familiar and all of the software they know, often niche, rare, or unmaintained, works correctly on it.

And so on.

And then there are instances where the consumers don't really have much say, like Blu-ray v. HD-DVD. They were well about even until the one supergiant corporation (Sony) swooped in with extra incentives for the other supergiant corporations (movie sudios) to get them to choose Blu-ray over HD-DVD, even though HD-DVD is ultimately superior.

So I sympathize with their intention to preserve faith in free markets, but their postulation that markets always make the right choice technically is silly. There are many other factors, including retraining costs, meddling by big players, etc., that can effect the ultimate dominance of a product.
It's true. For instance, raising children is imperative for the preservation of society.
If I remember my 2000AD days right, I think the date was when the newsagent should remove the comic from the shelves, more like a sell-by date than a published-on time.
I have been waiting for someone to write a post like this. Not because I think it's important to discuss one startup versus the other necessarily - they have very different markets in my mind - but because an exploration of the developing NYC aesthetic is worth examining.

I actually think it has a lot to do with early users. In the Bay Area, it's easy to find a large group of beta testers and early users who "get" technology in a profound way that (sadly) no where else in the country does. This contributes to the SV echo chamber and yields a certain type of feedback that in turn creates very distinctly "west coast" products. In New York, the number of truly tech-savvy social web types is much smaller and the majority come from media and advertising - ie, people who care first about design, and second about everything else.

While I'm sure the debate could rage all day about real growth and traffic stats, that's not what I took away from this article at all.
No. They're both O(N^3) in the dimension of the matrix. And it's more stable only in the sense that it's doing fewer operations. There's actually a great trick (again, in Numerical Recipes) when doing inversion to spend a few more (constant factor) cycles to iterate a correction to the limit of the precision of your number representation.

Really, check Numerical Recipes. I like their section a lot, though I don't have my copy handy to give you a cite.
Its important to note that not only do they mention the disincentive to work, but the disincentive to save and the disincentive to pay your debts.

How is discouraging people to save and pay their debts good for anyone or society as a whole?
The first page was the worst human interest story I've read. It was structured as though we are to pity the business owner while thumbing our noses at Yelp.

For those who haven't read it, essentially the biz owner trolled yelp and then hunted down a critic, and was arrested for battery. Best line: More than anything, she blamed Yelp.

Edit: If you read the rest of the article, it goes to a salon owner who actually gets it, and her business has benefited from it. Know your customers.
Nice: I just installed and played with this for 5 minutes. Assuming no significant bugs or problems, this is a welcome tool for when I have to use Windows. (I can't even imagine using Windows without cygwin and a bash shell.)
Actually the risk is a "geeks only" sign.
Bingo. Ever try logging out, clearing cookies and then looking at a view again?
I don't think that's even Yelps primary value proposition. They're much more of a social network than anything else. Their proposition seems to be more around providing a place for people to gain recognition for their taste. This is why they have the elite yelper program and what-not.

The result of that play is a huge site with a TON of reviews that create a lot of organic SEO traffic. The credibility of those reviews, while important, isn't really their upmost concern.

That's why withholding positive reviews (under the guise of spam control) is effective. They're effectively extorting you to create more content for them.

Is it intentionally designed that way? I have no idea, but I bet it's extremely effective.
Average karma is a meaningless metric.
I'm interested in CSG software that can calculate intersections between primitives with arbitrary precision (so that error does not accumulate - suppose that you wanted to use such a library to automatically generate manufacturable designs from broad geometric constraints - with current CSG libraries, you'd have to worry about precision, which would make such a program unwieldy and unreliable.)

I'd like to contact you directly, but I don't think hn has an IM feature.
Are people interested enough in this for a blog post? I studied numerical analysis and would be happy to post some of the basics if people are interested.
Henry Ford raising wage may give China tip on worker prosperity
"More Flame Bait," or why Charles Stross uses Macs
Ugh... Since Forbes can probably make this argument based only on the facts, why did they have to invent a "79% tax rate" for this person? It's simply not true.

Paying college tuition is not tax, and student financial aid usually does not take the form of a tax rebate. Therefore, including this in their "79% bogeyman" is inaccurate.

Furthermore, paying your home mortgage is not a tax, and relief on your mortgages may or may not take the form of a tax rebate. Again, it is inaccurate to lump this into the so-called 79% tax rate.

Forbes made this even worse by applying these expenses to the top 60,000 of the person's 120,000 income, and calling the entire thing the "marginal tax rate."

By my calculations, we're talking about a 27.5% marginal tax rate on the top 60k of her income, and then whatever the tax rate would be on her lower 60k of income. I'm going to estimate the tax rate is something like 20%, which is far less horrifying than 79%.

It's still true that income differences will affect financial aid and mortgage payments, so Forbes should point that out, but it's totally irresponsible to call this a 79% tax rate.
Death to Filesystems
btilly's reason is correct -- It's because Project Euler is about solving the problems for yourself, not just blindly copying and pasting. Although I'm starting to lean towards thinking that if people want to cheat, they will, and so if I can help someone (even myself) by posting the code, I should do so.

And yes, getting pointers on my Arc code would be helpful. So maybe I'll put everything up on github.
This is why all Buddhist monks die young.
Perhaps I should have been clearer on this: my example wasn't meant to imply that the authors of the study were lying. All I meant was that for some abstract proposition A, evidence of a benefit B gained from believing A is not evidence of A. The gym class is a case of B where A is false.
The Agony of Hadoop / Clojure Logging (and how to fix it)
The Top 11 Consumer Review Sites
Correct. I raise my LRD to you, Sir.
Yeah, print magazines have a kind of chronological arms race. No one wants to have a date that's earlier than the adjacent magazines on the stand.
I especially like how she blames the cluttered mess on poor sales. Maybe poor sales are a result of a cluttered store!
Elizabeth Warren wrote an excellent article about that last year:
http://www.huffingtonpost.com/elizabeth-warren/america-witho...
Why don't they have a link on their homepage to their own forum?

Any HN'er want to link to their Vanilla Forum here?
Now..two things.
1. Can anyone comment on the legality of this internet based extortion as opposed to "regular" extortion?

2. Is this by any chance the reason why the Google deal fell through? I know we heard otherwise but it makes me wonder.
I don't necessarily agree with the idea, but there is an economic theory that essentially states that the market is always right given that it has perfect information. You can agree or disagree with that theory, but I don't think what they're saying is necessarily absurd.
Sounds like that business owner Yelped herself!
There're costs to that economic output that are not reflected in its dollar value.

For example, what's the value of having a parent at home full-time? What's the value of having both parents home for dinner? A bunch of studies have shown that one of the best predictors for having successful, well-adapted children is how much time the family spends together. But how do you quantify that? You won't know what the exact payoff is until 10-15 years later, when the kids are well into their own careers and having their own children. And it varies a lot from kid to kid - someone who's performing well academically with a supportive peer group needs a lot less parental involvement than a loner with no friends who's threatening to blow up the school.

Or another example: when I went to college, I believe the fin-aid formula was that the college would take 100% of my assets, based on my age and income. That meant my gap year was revenue neutral - it didn't matter how much I worked or what I worked on, I wouldn't be able to keep any of it. But that gave me the freedom to observe and to try things out, without the stress of trying to make a lot of money, and in the process I found my eventual career.

You don't want to run an economy like this - there needs to be some accountability so that people work on things that are actually useful. But a high school grad who's time-limited to one year of work isn't going to accomplish anything actually useful anyway - instead, that gap year is an investment in perspective, a way to understand more of the world before you commit to four years in college.

The same thing often comes up in research - a short-sighted focus on increased economic output leads you to miss opportunities that have no obvious dollar value attached, but can be big economy-changers in the long run. How long did it take GMail to become profitable, and would it have existed had Google had the same quarterly bottom-line orientation that most public companies do? How about Google itself? If Larry and Sergey had done the economically rational thing in 1995, would we still be searching on AltaVista? Is Twitter making money yet?
They just meant that you misspelled "carefully"
I took an electricity class at the local community college last year. The teacher spent about 20 minutes of the first lecture doing exactly this. He presented a basic model of the brain where mental effort creates new connections in the brain and actually physically changes the form of the brain. The summary was that even if we thought we didn't have the mental ability for the course at the start, long-term effort would turn us into people with that mental ability.

I wondered if he was familiar with some of this research. And also whether it made a difference in class performance.