Search found 256 matches

by Tub
Mon Mar 27, 2017 8:04 am UTC
Forum: Computer Science
Topic: Deliberately bad algorithms
Replies: 108
Views: 22550

Re: Deliberately bad algorithms

Interesting tradeoff. Though I have yet to meet a problem that requires checking existence of a path without actually returning the path. it uses O(log^2 n) extra space. (the undirected case can be done with O(log n) space) Really? It would seem that the call stack is at most O(log n) calls deep, an...
by Tub
Sat Mar 25, 2017 10:41 pm UTC
Forum: Science
Topic: Toothbrush, glasses, and clock
Replies: 15
Views: 339

Re: Toothbrush, glasses, and clock

ThirdParty wrote:I also tried applying the toothbrush to the cell phone while taking the picture. Still normal.

Only a true scientist would apply a toothbrush to a cell phone and consider that process "normal". Well done.
by Tub
Sat Mar 18, 2017 12:17 pm UTC
Forum: Coding
Topic: Coding: Fleeting Thoughts
Replies: 9564
Views: 1345822

Re: Coding: Fleeting Thoughts

(I know that's kind of dangerous because you now have two places where you can modify the set, but in this context, I'm pretty sure it's okay) Either wrap all related sets in another class, which guarantees that additions/deletions are propagated correctly, or (in C++) use a combination of shared_p...
by Tub
Thu Mar 16, 2017 5:48 pm UTC
Forum: Hardware
Topic: Best Hard Drive For Gaming?
Replies: 11
Views: 774

Re: Best Hard Drive For Gaming?

I hope you mean $250 on a 1TB SSD: https://www.newegg.com/Product/Product.aspx?Item=N82E16820226596 "bucks" is a currency that may or may not be similar to either us dollars or euros and may or may not include VAT. That one is 280€ here, and a 500GB drive is just over half of that. But th...
by Tub
Thu Mar 16, 2017 4:25 pm UTC
Forum: Science
Topic: Free Will
Replies: 55
Views: 1350

Re: Free Will

Note that I'm talking about processes and not the universe as a whole. This process could be any subset of the universe and, assuming the universe is infinite (and so an observer is guaranteed access to more resources than exist in the subset), it is, in principle, possible for an observer to predi...
by Tub
Thu Mar 16, 2017 3:42 pm UTC
Forum: Hardware
Topic: Best Hard Drive For Gaming?
Replies: 11
Views: 774

Re: Best Hard Drive For Gaming?

M.2 is electically compatible with PCIe, so adapter cards are cheap - there's not a single controller chip on them. But I doubt the old computer has PCIe 3.0, and 4x PCIe 2.0 is limited to 2000MB/sec. It would be cruel to buy a 3200MB/sec drive and put it in there. I expect the additional speed to b...
by Tub
Wed Mar 15, 2017 11:07 pm UTC
Forum: Science
Topic: Free Will
Replies: 55
Views: 1350

Re: Free Will

An observer can, in principle, predict with certainty the outcome of a deterministic process. To prevent anyone from getting the wrong idea, I think it's worth pointing out that determinism does not imply predictability. For any observer inside of the deterministic process we call "universe&qu...
by Tub
Wed Mar 15, 2017 10:38 pm UTC
Forum: Science
Topic: Eternalism. Does it allow free will?
Replies: 16
Views: 391

Re: Eternalism. Does it allow free will?

If you really believe so, then try going without the strong force for a day.
by Tub
Fri Mar 10, 2017 10:51 pm UTC
Forum: Science
Topic: Science-based what-if questions
Replies: 233
Views: 10156

Re: Science-based what-if questions

So I have a question - if you are orbiting a neutron star at say 1AU and look at it, what do you see? You probably won't see a neutron star. Those things are tiny. The exact details depend on the neutron star, of course. At 1 AU, a 10km big ball is very hard to see, no matter its mass. There's a bi...
by Tub
Fri Mar 10, 2017 6:52 pm UTC
Forum: Science
Topic: Free Will
Replies: 55
Views: 1350

Re: Free Will

doogly wrote:And I throw these links out there like pearls before swine.

Take solace in the many worlds interpretation, and know that somewhere, in some remote part of the wavefunction, someone actually clicked your link. Most certainly not in *your* part of the wavefunction, but somewhere.
by Tub
Thu Mar 09, 2017 1:29 pm UTC
Forum: Science
Topic: Free Will
Replies: 55
Views: 1350

Re: Free Will

Copenhagen is the most used, accepted, and "standard" interpretation out there. Other interpretations are mostly considered semantics at best. Many worlds is "what if there's an infinite exponential amount of worlds that never interact otherwise and you can never prove and makes no c...
by Tub
Thu Mar 09, 2017 9:09 am UTC
Forum: Science
Topic: Free Will
Replies: 55
Views: 1350

Re: Free Will

Yes, quantum things are probabilistic in nature, so you have an appearance of randomness in measurements. That does not contradict the deterministic evolution of the underlying quantum states (including all its probabilities). The only interpretation with non-determinism is the copenhagen interpreta...
by Tub
Thu Mar 09, 2017 8:08 am UTC
Forum: Science
Topic: Free Will
Replies: 55
Views: 1350

Re: Free Will

I think that it is real and that determinism is wrong, but I'd like to know if you guys have any scientific evidence of free will existing that I could use. Since you're mentioning determinism: Current scientific consensus is that the universe is deterministic. See the Schrödinger Equation , an equ...
by Tub
Thu Mar 09, 2017 7:45 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1808: "Hacking"
Replies: 32
Views: 2571

Re: 1808: "Hacking"

xtifr wrote:Actually, the first thing I do after compiling is usually linking.

Really? The first thing I do after compiling is to fix all the typos that caused the compilation to fail.

If only gcc had a switch to automatically run that step.
by Tub
Wed Mar 08, 2017 6:09 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1808: "Hacking"
Replies: 32
Views: 2571

Re: 1808: "Hacking"

pogrmman wrote:That would be a great switch to have -- what's the first thing most people do after compiling? Run the executable they just made. Why not make it easier?

The switch is called

Code: Select all

&& ./a.out

and must be appended at the end of the command line. :roll:
by Tub
Tue Mar 07, 2017 9:00 pm UTC
Forum: The Help Desk
Topic: Linuxifying my PC?
Replies: 11
Views: 846

Re: Linuxifying my PC?

AMD's open source drivers are pretty great. Your HD3450 (R600) should work out of the box in pretty much any distribution, including 3d acceleration and hw video decode.

Sound card.. you'll have to test. Probably fine, but no guarantees.
by Tub
Tue Mar 07, 2017 12:03 pm UTC
Forum: Mathematics
Topic: What happens if you de-discretize time in the blue eyes riddle?
Replies: 9
Views: 931

Re: What happens if you de-discretize time in the blue eyes riddle?

It's funny, because time is literally the only thing not required to be discrete in the riddle. The people are discrete. The information they have is discrete. Their chains of reasoning are discrete. The ferry dispenses discrete amounts of information. The solution hinges on alternating phases of a)...
by Tub
Tue Mar 07, 2017 11:07 am UTC
Forum: The Help Desk
Topic: Linuxifying my PC?
Replies: 11
Views: 846

Re: Linuxifying my PC?

Audacity will work just fine, so should a line-in (unless you have an exotic sound chip). You could of course buy an USB sound card, possibly with better input quality than a decade old onboard sound chip, and rip your stuff directly on your laptop. Drivers for the video card might give me some head...
by Tub
Thu Feb 23, 2017 9:46 am UTC
Forum: Mathematics
Topic: Probability problem
Replies: 13
Views: 898

Re: Probability problem

Can you clarify the ownership formula? Does the cell's own colour count, or only the colours of the neighbours? How does it work on the corners, do the neighbours "wrap around", or do the corner cells simply have fewer neighbours? Am symmetry argument says that P(B=k) = P(R=k), but any fur...
by Tub
Wed Feb 22, 2017 2:54 pm UTC
Forum: Computer Science
Topic: Why don't we use composite hashes?
Replies: 4
Views: 521

Re: Why don't we use composite hashes?

hashing x with multiple functions gives the attacker more information to work with, in that sense, and increases the attack surface But.. in my definition, the attacker already knows one plaintext. If running additional hashes on that plaintext was an advantage, then the attacker could already do i...
by Tub
Wed Feb 22, 2017 1:52 pm UTC
Forum: Computer Science
Topic: Why don't we use composite hashes?
Replies: 4
Views: 521

Why don't we use composite hashes?

Hello, Let's use a simple definition: a hash is a function which transforms a message m into a fixed-length value H(m). And all we care about are preimage attacks: Given a message m 1 , how difficult is it to produce a message m 2 (with m 1 != m 2 ) so that H(m 1 ) = H(m 2 )? We used MD5. Flaws were...
by Tub
Tue Feb 07, 2017 11:11 pm UTC
Forum: Science
Topic: The (somewhat ridiculous?) holographic principle
Replies: 4
Views: 1192

Re: The (somewhat ridiculous?) holographic principle

Ah, a post from Tchebu. Though rare, they're always insightful. Thanks for taking the time to write. I took this as an excuse opportunity to watch smart people talk on youtube, so let me quote this audience question: Leonard Susskind | Lecture 2: Black Holes and the Holographic Principle , around 1h...
by Tub
Sun Feb 05, 2017 8:45 pm UTC
Forum: Coding
Topic: CSS frustrations
Replies: 7
Views: 616

Re: CSS frustrations

If your boxes have a height, you can probably remove nowrap and the br's again. Font engines differ, and the browser can make better decisions about it. Also, links to small example pages with the proper css/html generally make it easier for people to help you. Alas, it's on my dev server, which is ...
by Tub
Sun Feb 05, 2017 11:05 am UTC
Forum: Coding
Topic: CSS frustrations
Replies: 7
Views: 616

Re: CSS frustrations

Don't rely on flowing text to determine an element's height, unless you set line-height, font-size and nowrap and are very sure about what you're doing. It's usually safer to start with a fixed box height, overflow: hidden, then fit the contents inside, instead of the other way around. This way, if ...
by Tub
Fri Feb 03, 2017 12:56 am UTC
Forum: Science
Topic: The (somewhat ridiculous?) holographic principle
Replies: 4
Views: 1192

Re: The (somewhat ridiculous?) holographic principle

I'm not sure if the goal of the work is to make predictions. If the idea is that this 2d-thing and that 3d-thing are equal, then there's not going to be an experiment that'll tell you whether the universe is actually 2d or 3d - any experiment that could distinguish between the two is a failure of th...
by Tub
Sat Jan 28, 2017 1:13 am UTC
Forum: Science
Topic: Very hot coffee ?
Replies: 10
Views: 1013

Re: Very hot coffee ?

Well, if you picked a regular cup of coffee and instantly heated it to 5800K, then the sudden rise of pressure would be pretty explosive, and the comparison to the stick of dynamite might be valid. But if you just have a 5800K cloud of coffee at air pressure, and you put it on a table, then you need...
by Tub
Mon Jan 16, 2017 6:15 pm UTC
Forum: Coding
Topic: Coding: Fleeting Thoughts
Replies: 9564
Views: 1345822

Re: Coding: Fleeting Thoughts

RRDTool seems like a pretty useful thing. It can store regular measurements (like CPU temperature, system load etc) in a way that avoids the overhead of RDBMS et al, and it'll automatically provide lower-resolution series with different cutoffs. For example, store the last 24 hours in 1-minute accur...
by Tub
Mon Jan 16, 2017 12:23 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1785: "Wifi"
Replies: 42
Views: 3156

Re: 1785: "Wifi"

ucim wrote:So... what is the "proper" way for a hotel guest to ensure that they are connecting to a wifi that is trusted[..]?

You verify the 802.1X certificate. If the network doesn't have one, you don't trust the network. End of story.

I know you wish it was different, but it isn't.
by Tub
Sun Jan 15, 2017 2:32 am UTC
Forum: Coding
Topic: Coding: Fleeting Thoughts
Replies: 9564
Views: 1345822

Re: Coding: Fleeting Thoughts

The good news: programs are just finite-length strings of bits, so you can enumerate them if you want. The bad news: proper testing is impossible (not just due to the halting problem), and heuristic testing will pass too many broken programs. Say, you're testing a sorting algorithm on [], [1,2,3,4,5...
by Tub
Sat Jan 14, 2017 1:33 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1785: "Wifi"
Replies: 42
Views: 3156

Re: 1785: "Wifi"

Having a password on their wlan may not be a security thing, but a legal one. Entering a password protected network may be treated differently from entering an open one; in cases of illegal activities the owner may have more liability if the network was not protected against misuse. I'm currently sw...
by Tub
Sun Jan 08, 2017 12:15 am UTC
Forum: Science
Topic: Light in a fog
Replies: 14
Views: 945

Re: Light in a fog

Probably neither. I don't think you can assume a constant 1000W/m² radiation from every direction everywhere inside the fog. Even if all the scattering inside the fog evens out, you have a huge portion of the light that'll get reflected back to the sun immediately after entering the fog. Summing up ...
by Tub
Sat Jan 07, 2017 2:40 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1782: "Team Chat"
Replies: 84
Views: 5582

Re: 1782: "Team Chat"

markfiend wrote:I use screen+irssi :mrgreen: GOOMHR

screen+irssi+bitlbee. bitlbee is a gateway for many popular IM protocols (jabber, icq, ...), so all my chats can use the same client.
by Tub
Fri Jan 06, 2017 2:41 pm UTC
Forum: Science
Topic: Would the disco ball really still end up inside a black hole?
Replies: 12
Views: 1076

Re: Would the disco ball really still end up inside a black hole?

spherical shells behave externally as if all their mass is at the centre. This is just as true in GR as it is in Newtonian gravity. Once the light pulse sphere is within the 1 light-second radius it will therefore behave as a black hole externally and thus won't be able to escape. But which observe...
by Tub
Wed Jan 04, 2017 10:36 pm UTC
Forum: Science
Topic: How to calculate energy in humans?
Replies: 22
Views: 1634

Re: How to calculate energy in humans?

doogly wrote:That was not the original idea, that is a lie told to children.

By no other than mr hawking himself :roll: But alright, I'll try to erase that lie from my mind.
by Tub
Wed Jan 04, 2017 1:42 am UTC
Forum: Science
Topic: How to calculate energy in humans?
Replies: 22
Views: 1634

Re: How to calculate energy in humans?

you can convert all matter to pure energy simply by compressing it into a black hole, so it evaporates and radiates heat. Ignoring the lack of experimental evidence for hawking radiation, does it say anywhere that hawking radiation has to be exclusively massless particles? I've always understood it...
by Tub
Tue Jan 03, 2017 11:32 pm UTC
Forum: Science
Topic: Science-based what-if questions
Replies: 233
Views: 10156

Re: Death ray from above.

Have you read https://what-if.xkcd.com/145/ ? It'll tell you why the idea you're having doesn't work that way. You can't have a death beam, you need a focal point. Considering that the sun's surface is only about 5500°C, you cannot de-focus your beam too much if you want to reach 1000° on the target...
by Tub
Tue Jan 03, 2017 11:04 pm UTC
Forum: Science
Topic: How to calculate energy in humans?
Replies: 22
Views: 1634

Re: How to calculate energy in humans?

Start by learning about entropy. We know about conservation of energy, so energy cannot be created or destroyed. But every day, we "use" energy, don't we? At least the bills from my power company seem to imply so. If energy is conserved, why can't we plug in our laptop until it's full of e...
by Tub
Tue Dec 27, 2016 12:54 pm UTC
Forum: Science
Topic: How to calculate energy in humans?
Replies: 22
Views: 1634

Re: How to calculate energy in humans?

How would someone go about calculating the total amount of energy in a person? [..] I'm trying to determine how much energy a person could get out of a human. Those are two very different questions. "Energy" and "usable energy" are two different concepts often mixed up by non-ph...
by Tub
Fri Dec 23, 2016 7:14 am UTC
Forum: Mathematics
Topic: Probability distribution on the power set of natural numbers?
Replies: 12
Views: 1011

Re: Probability distribution on the power set of natural numbers?

Well, the infinite subsets with finite complements correspond precisely to these ambiguous cases with two representations. These are exactly the real numbers with terminating binary representations, and these are enumerable, so they have measure zero in [0,1]. That seems to be enough; have I missed...
by Tub
Thu Dec 22, 2016 11:47 pm UTC
Forum: Mathematics
Topic: Probability distribution on the power set of natural numbers?
Replies: 12
Views: 1011

Re: Probability distribution on the power set of natural numbers?

I assume you intend to find a distribution where (informally) each set has the same probability? Otherwise your claim would depend on the chosen pdf.. You can try your bijection, but after fixing the duplicates it'll get a bit ugly. I've seen several such constructions in my life, none of them simpl...

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