skysight-inc/HackerNews huggingface dataset:
You've probably used Gauss-Jordan elimination over the reals. What properties of real numbers make Gauss-Jordan elimination work?

The real numbers have addition and multiplication operations which each obey commutative, associative, identity, and inverse laws; and multiplication is distributes over addition. These properties are all that's required for Gauss-Jordan elimination to work.

(We don't need other properties of real numbers, such as properties involving convergence of sequences, which you may have studied in calculus or real analysis class.)

A set and binary operators + and * which have all of these properties, are called a "field" [1]. The real numbers, rational numbers, and complex numbers are probably your most familiar examples of fields.

When talking about a field like "the field of rational numbers, Q", you're actually referring to a data structure (Q, +, *) which includes definitions of the addition and multiplication operators.

Since most fields have "standard" addition and multiplication operators, often mathematicians drop them from discussion. Kind of like, when you're discussing a program with a colleague, you say, "Add the offset to the base," your colleague doesn't ask, "Add them as integers or floating-point numbers? What should I do if they overflow?" The answers to these questions are almost always clear from context, and also almost always near-universally standardized, at least within a particular programming language.

Anyway, as other posters have noted, the integers modulo p, where p is prime, are actually a field. It's obvious that Z_p has most of the properties of a field, but multiplicative inverse is interesting. The proof of existence of multiplicative inverses mod p -- and a fast O(log(p)) implementation of finding them -- is the Euclidean algorithm, one of the oldest algorithms known to mankind. [2]

[1] http://en.wikipedia.org/wiki/Field_%28mathematics%29

[2] http://en.wikipedia.org/wiki/Euclidean_Algorithm
> You are not saving anything there. A session should really only contain user id.

So it looks like Flask is using something that just deliberately runs pickled strings. Even if I know my own secret key, I don't exactly need to be able to send myself arbitrary code. So JSON seems to make sense to me for my use cases.

pickle.loads("cos\nsystem\n(S'whoami'\ntR.")

Right.. so anyway, does anyone know which session engine I want to use with Flask if I want to generate a token for a user's session, which I can then later revoke if I end up hating that user's session but not two other sessions?
Not necessarily. They may have gotten access to an old backup of your server. This misfeature would let them escalate that to a compromise of your live server.

Attacks often involve multiple rounds of escalation as people keep on increasing their level of access. You want that escalation to be as hard as possible. Therefore you really don't want there to be a fact that could be floating around your organization in various ways that can be used to go straight to executing arbitrary code on your production site.
API's and services like this are Key in making it so that more people will be able to afford medical care. Solving the current cluster F* of paperwork and time involved in establishing eligibility is one of the lowest hanging fruits in cutting medical costs (....NOTE: As opposed to more complicated cost cutting concepts such as preventative care) A typical Doctors office of 2 or 3 practitioners may have 2 or 3 or more support people spending their day faxing back EOB's to insurance companies, etc. Those dollars directly affect the cost of Health Care. This is Great.....X12 is arcane, good riddance. There are actually some insurance clearinghouses that will pay you to use them (if you have high enough volume) as they are paid by the insurance companies and/or through government incentive programs.
The initial problem is building and sending the camera to Mars.
When I think about innovative companies in software and computer engineering, Apple is one of several companies that comes to mind.
It's worth noting that Steve Jobs turned innovative artistic design, not just innovative engineering, into economic value. One of Job's criticisms of Microsoft and Google was their lack of appreciation for "the humanities and liberal arts" ( http://www.vanityfair.com/business/2012/08/microsoft-lost-mo...). He saw Social Science as a component to making great products.

I'm a Computer Science Major. If I was recommending a Freshman what to Major in, I would recommend looking into something within Science, Engineering, or Business. They're unlikely to get an upper middle class salary majoring outside of those three fields.

However, just because a field doesn't produce dividends doesn't mean that it does not have educational value. A political science degree doesn't make money, but we can't have functioning governments without an understanding of politics and government.

Instead, we ought to consider the fact that college spending is only 3.3% of U.S. GDP. Re-prioritization of spending, and optimization of spending can carry American education forward. That's not a huge chunk of the American economy's wealth. People are falling into debt because the burden of college spending has been placed on individuals, rather than on federal and state funding. Over the last 30 years Federal and State expenditures to college education have dropped. In result, Colleges increase their tuition rates, and students and their families have a tougher time paying for college.
No Python program should ever try to unpickle data from an untrusted source.
>Meanwhile I profit because HFT makes the market more efficient for me.

High frequency trading does not increase liquidity in a way that directly benefits anyone but high frequency traders. Being able to liquidate assets in a fraction of a second less does not benefit the normal investor. Not even getting into the volatility it adds.
I posted a follow-up -- there may even be a way to fully reduce SRP into SHA1 given that N is a 256-bit value.

See: http://www.opine.me/srp-to-sha1/
It would be cool to provide a sample API with test data.
You could either require sign-up (as individual or organization, but not necessarily a registered company) or don't. This would enable someone to hack something together before they establish a company.
Wow.

This manifesto, I believe I'll be pulling quotes out of it, for years to come.
Not sure I get what you are trying to say here. Are you saying placebo/nocebo effects are real or not?

Using "measurement error" as an argument is kind of insulting to the testers as most of them have got to have a grasp of statistics and other factors in order to publish results that aren't going to get them laughed at by the scientific community.

How do you explain placebo effects in double blind tests?
French Startup: Azendoo To Take On Asana? INTERVIEW
Google Scholar "Updates" - sifting through the scientific literature
Add Code Syntax Highlighting to any page in “Three” Lines
Funny, I was just using those same sources to calculate sunrise and sunset for Curiosity.

I think the latitude for Curiosity is wrong on that Nasa site and in the data file for the downloadable clock they have. I think it should be negative, based on the other sources. I emailed the listed contact to ask.

EDIT- Before I found that site, I was working from an ancient clock written in QBasic, described here: http://www.spaceacademy.net.au/spacelab/projects/marsclok/ma...
Another problem we saw (but didn't mentioned):
You can't logout sessions on the server-side. If you forgot to logout somewhere, your session will stay valid. And an expiration-date for the sessions is optional. Neither changing your password nor contacting the site admins will help you.
It's signed, so the integrity is ensured as long as the secret key stays secret.
It's also mentally exhausting and drains your willpower. While it may be a sign of good character, being like that 24/7 (even when you don't feel like it) is a good recipe for driving you insane eventually.
Flask doesn't have a user system and as such does store nothing on its own in the session.
I'm guessing there is a lot of data that never gets sent to earth. Do they send thumbnails of the images to determine what is interesting? Is there a software tool available that creates a thumbnail and then creates a copy of the original image that is dependent on the thumbnail to be recreated. If you can't tell I wasn't really sure how to word that last sentence. Basically, less data would be required to transmit because you are only sending the data required to reconstitute the real image. Depending on the size of the thumbnail this might result in a negligible difference.

For example, a very naive implementation might create a thumbnail from every pixel where x or y is odd and then when/if you want the original image you can get the data required to put the image back together (it would be a similar sized thumbnail but with the even pixels) For this naive approach the thumbnail would likely be much larger than you want and would not help at all :)
1) Congress passed a law after a lot of lobbying. The reasoning was that when a student graduates they have substantial debt and no assets, so every student would just declare bankruptcy the day after graduating and wouldn't have to pay back the providers.
Wow -- pleasantly surprised to see that response. Very cool to see you sharing data.
I don't have access to Flask or the ability to answer this question in any reasonable amount of time, so I'm asking. If your session has the user id, what format is the user id in? Is it the email address, or goodness forbid, an autoincremented numeric ID? Or anything else even remotely guessable? If so, you've still got a problem.

Obscuring through an opaque token of suitable entropy means that it is effectively impossible to guess a valid token. Accepting the client's idea of who the user is is playing with fire.
I'm not a doctor, but your case sounds more like a vasovagal response than a panic attack.

(I have an interesting vasovagal response -- I can draw my own blood just fine, and a nurse can draw my blood if I don't watch; but I've fainted from watching a nurse draw my blood.)
Is there a reason why session storage isn't local, with clients only given the index into that storage?

Allows for any size/types of data but the worst case scenario-without code execution is that an attacker hijacks an existing but valid session.
Maybe also put up a comparison with your competitors and/or highlight the features that make you a better choice.
Such drives would be far more expensive than what we use daily. Factor in electronic shielding needed to prevent soft-errors from cosmic rays: http://en.wikipedia.org/wiki/Cosmic_ray#Effect_on_electronic...
That's not really true. You could easily add another piece of information to your session that is derived from something stored with the user (for instance a running counter). So if someone runs away with your session you add a button "logout everything" which increments the counter. When the session is accessed for the next time the counter values don't match and the user is logged out.
I'm sorry I was an asshole.

Please don't hesitate to submit on account of jerks like me in the future. Not to rationalize my behavior, but I do think the typos were a large part of what gave me a bad impression, inclining me to question whether it was up to the site's standards. Proof-reading carefully before submitting to HN might have made a big difference to my reaction.

That said, I am embarrassed by how much of a dick I was, and that certain other people voted me up (you know who you are). I could never have said something that mean to your face, which makes me a coward as well. Let that be a lesson to the kids out there; don't post mean, stupid comments at 1AM (or any other time)!
Flask doesn't have its own user system, in the wild one sees stuff like user-ids and so on. It makes it very easy to make bad mistakes.
This probably has more to do with the massive antenna (also known as a radio telescope) here on earth that are used to pick up the signal. Fortunately a few such antenna exist around the globe, so Mars should be in view of one of these antennas at all times. According to Wikipedia (http://en.wikipedia.org/wiki/Deep_Space_Network), radio telescope complexes used by NASA are located at:
Goldstone Deep Space Communications Complex	near Barstow, California, USA
Robledo de Chavela	near Madrid, Spain
Canberra Deep Space Communications Complex	near Canberra, Australia
If those are the only two possible answers that you'll accept, he's not saying anything you will hear.

>Over any period of time, a person will have a great many variations in mood, pain, etc.

>When [...] a subject or researcher has been primed to expect [an effect], the subject or researcher is more likely to notice that effect.

>to this extent, a placebo (or nocebo) effect can be accounted for [by these measurement errors.]

>It is plausible that some specific placebo effects like reduction/increase of pain response, anxiety, and mood could actually be real psychological effects[.]
Coding a Pixel-Style Video Game Fansite in HTML5/CSS3
Crime News: Real-Life Slasher Kills Conscious-Girlfriend With Machete
Very interesting read of one person's (very credible) opinions about China. Yet...

The title is a tautology. I can't help but feel that anyone from country X will every be integrated into any other country, as long as they still want to be themselves. Which is what the author never really states. Had he bought into the materialistic lifestyle, asked everyone how much money they made, and insisted his kids cram for elementry school exams, and toed the party line (whatever that may be), then maybe he would've been considered Chinese (I bet he'd say you still wouldn't but he didn't even consider that possibility). But no, he wanted to be a Westerner in China, and by definition, never become Chinese.

I lived in Europe for half of my life before age 30. I was fluent and mistaken for a native of the country where I lived. Yet, I could not help but retain my American perspective; I don't think I could give that up even if I wanted to. So even if I blended into the culture and wanted be a native, I could not feel like one myself. I came "home" to the US and don't feel American anymore either--I think that will be the author's fate in Britain. I have American friends still there, native by any standard, yet still consider themselves American by choice.

So I think it comes down to giving up one's identifying culture. The ironic thing, is that Chinese (and many other foreigners) do it all the time when they immigrate to the West. To me, that is the quandary of immigration: how do they manage to embrace the host culture so much that they no longer identify with their native one. It seems so much easier to do from East (India, China) to West (US, mostly). It seems like it's much easier to go from a culture of community to one of individuality than vice-versa. Why is there a lack of symmetry?
I'm not sure btilly's argument was entirely sound. On the reddit thread for this post (in /r/math) counterexamples seemed to outnumber examples. (Not that that is itself evidence that this phenomenon's real.)
Ok, lets separate two things.

1) There is no business where joe random person writes up a patent, gets it issued, and then BigCorp comes along and offers to buy it for eleventy billion dollars. That is a myth, a pipe dream, a fantasy. Doesn't happen (not that it can't happen, just that it doesn't)

2) You invent something to solve a problem, generally people who invent things are quite taken with their own inventions, so they build them. A provisional patent is a good way to establish patent protection for your idea before you've invested too much time and effort into it, and it can make it easier to talk to third parties about it because they can't "steal" it if you've already got a provisional filed.

That said, you either self fund, or you convince folks of how great it is to fund you, and you convince them to help you build it. Then you find people who have the problem it solves and you try to sell it to them. If they buy it, you build more and continue. If nobody buys it, well you go on to your next idea. If you can't sell your idea you might partner with someone who is good at selling things.

This is all basic stuff. Its not "easy" in that there aren't any "easy" roads to success, if there were it would be trampled by everyone using it.
Creepy Spying System Revealed by Wikileaks, Which Then Gets Hit by DDOS Attack
I like the idea of processes dumping structured objects: pipes are rather often used for the processing of structured data, and while tabulated output certainly makes it easier, we still end up effectively using constants: cut to the third column, sort the first 10 characters, and print the first four lines.

This method is fragile when given diverse input: what if the columns could themselves contain tabs, newlines, or even nul bytes?

Passing objects as binary blobs, on the other hand, doesn't allow for ease of display or interoperability with other tools that don't support whatever format they happen to be. This, of course, can be rectified with a smart shell with pretty-print for columnar data (insofar as a shell could be charged with data parsing; you may imagine an implicit |dprint at the end of each command line that outputs blobs).

I'd also be interested in seeing a utility that took "old-format" columnar data and generated structured objects from it, of course, with the above format caveats.
RMS does this every year
If I can do a slight PG impression, "what problem does this solve?"
Yeah. We're struggling to describe it. We've got a bunch of different lines that come close.

"micro-app" is a (probably poor) compromise. It sortof hints what they might do better than Activities or whatever...
> Fixed.

Cute.

You must really be fan because that's another thing Arment likes to do. He writes snarky "fixed" versions of quotes from people saying remotely positive things about Android or anything that can be construed as negative about Apple.

Opinionated, certainly, but I've found next to nothing in the way of facts in his arguments and rarely even a stated rationale.

Face it, Arment is exactly what I described, even he knows it. He demonstrates it with pride:

http://www.marco.org/2011/04/10/fanoboy-fan-boi
I am fairly amazed that they need to do this because of what looks like space constraints. I wouldn't have thought that programming code would take significant space and the potential for screw ups just seems way too high to my mind.

I hope they get it right...
I don't use latitude yet for any calculations. The longitude is given in degrees E but the formula requires degrees W so I just subtract it from 360.
The core problem is that state and federal funding of colleges has consistently been going down over the last 30 years, and continues to go down. When colleges get less money from government spending colleges either have to cut spending (and in result provide less to students) or increase tuition.

The high tuition causes student debt, so the only way to cut student debt is to decrease tuition.

Their are only three ways to get tuition to decrease.

1. Increase Federal and State funding of colleges. As I mentioned in an earlier response, this is doable. College spending is 3.3% of GDP in the USA. Looking at the economy and country as a whole, that's not huge. Re-arrangement of spending, increased federal and state investment, and optimization of spending could reduce student debt a lot.

2. Get rid of much of Universities. Turn Universities into Trade schools and get rid of many University programs. This is not really the approach I want to see, as I think universities have a lot to offer the world in their current complexity.

3. Find Technological solutions and applications that reduce the cost of education without reducing its quality. This is the Entrepreneur's job.
I suppose he'll have to start with defining which licenses he thinks are acceptable. CC-SA? Probably. CC-BY-NC-ND? Maybe? Maybe not?

How about patents? Trademarks?
Toilet paper. Is there open source toilet paper? I don't think anyone is 3D printing that yet.
>Are you saying placebo/nocebo effects are real or not?

It's not a yes or no answer. Part of what we call "placebo effect" is certainly the result of priming and confirmation bias, but for some specific subjective phenomena (like mood), it is plausible that the effect is real.

>Using "measurement error" as an argument is kind of insulting to the testers as most of them have got to have a grasp of statistics and other factors in order to publish results that aren't going to get them laughed at by the scientific community.

>How do you explain placebo effects in double blind tests?

Being aware of cognitive biases doesn't immunize you to them. There isn't even very good evidence that being aware of cognitive biases reduces your susceptibility to them. There is no shame in that, and any scientist who is insulted by the suggestion that s/he is susceptible to biases should go back to Science School. What being aware of biases does allow you to do is design experiments that compensate for those biases.

And that's the whole reason that we have double blind tests. We know that since humans have to administer and participate in experiments, a lot of biasing factors are going to come into play. So we have come up with designs like that which allow us to measure the extent to which the effects we appear to see are due to biases (or the power of suggestion), and how much the effects can be attributed to an actual effect of the drug.
Woah.

http://www.kickstarter.com/projects/818526066/the-grassroots...

Hollywood Actor Jason Biggs (from American Pie) had his $5,000 goal kickstarter campaign FAIL. F.A.I.L. And he's in Hollywood. People know him. He knows people. Wow.

I guess this goes to show that success is never guarenteed. One cannot predict future success based on past success, or future failure based on past failure. It also makes me feel really good about my own kickstarter campaign failing.

Wow this made my day. Poor guy though, it must have been a huge "wtf" for him.

edit: Changed "oh my god" to "woah" to avoid getting any more downvotes. As an atheist I'm curious to know weather it came from offended christians or vengeful atheists.
Don't need to always use sed and awk. You can more easily sort, without recoursing to cut. You can let your pipe work on ranges.

Basically, use your imagination :-)
Gotcha. I run VirtualBox with an IE8 and IE9 VM for JsTestDriver, BusterJS, or the like. For Selenium though, I use SauceLabs to run it on all sorts of browsers and they actually provide you with a video of the test too. It's not free, but it's definitely worth the money.

"It's mainly to ensure that while I'm changing something in one place I don't inadvertently screw up a page someplace else that I may forget to check."

It all comes back to design by testing. Personally, my apps use a lot of layouts, views, and helpers so an automated way to check that a change in one place doesn't affect my UI somewhere else is paramount.

The key here is that it's automated. I use continuous integration, and introducing even one human element breaks the flow of quick pushes and updates.

As for sketching out page design, "form follows function." I'm not thinking about the look of the app at all. I'm not a designer, but once my HTML is written I can show a talented designer exactly what they have to work with to create the best UI/U possible. Basically, I'm not a fan of design-driven development.

I wish I could attach an image so you could see where I am with my current project. It's a logo at the top, followed by a list of links, a dropdown, another list of links, some content, etc. One on top of the other, no design at all. Black text, white screen. It is very clear though what the page is suposed to accomplish. Let the designer do their job, and I'll TDD my CSS when I turn their vision into code.
I think you're reading more into my comment than there is.