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October 27

IP address geolocation on cellphone

When I'm using it to surf the Web, my Sprint phone has started giving me random things out of Russellville, Arkansas: for example, when I used it to Google the phrase <fajita "ghost pepper sauce" arby's>, it asked if I wanted to search for Arby's stores in Russellville, and it gave me information (including address) about one of their stores there. Going to Special:Mypage on the phone, I learnt that the phone's IP address was 68.28.147.123 right then, but WHOIS and GeoLocate both say that it's merely a generic Sprint address without anything geo-specific, and the Arkansas identification obviously isn't based on my physical location, since I'm in central Virginia. Any ideas why the phone would start focusing on a city that's 900 miles away from me? Nyttend (talk) 00:18, 27 October 2016 (UTC)[reply]

Geolocation services based only IP addresses are guesswork, and different services produce different guesses for the same IP. The results of these guesses are often laughably wrong, and are wildly inconsistent to boot - even for ADSL addresses, never mind mobile. Worthwhile web services use GPS/GLONAS, cell-tower information, and/or a Wi-Fi positioning system. You (or some update, or some security software) may have disabled the Google Search app's access to the location API. -- Finlay McWalter··–·Talk 15:55, 27 October 2016 (UTC)[reply]

Why is everything so big?

The computer at the library froze and something done to unfreeze it made everything really big.

I read the solution was to use CTRL and minus but when there was a place to click to return to default, that made everything big again. Plus even when I reduce everything to what looks "normal" the URL and the web site names above it are still big, and the start button, Internet Explorer and Google Chrome logos, time and everything else at the bottom of the screen is still big.

Also, the fonts on Wikipedia look weird. I have Monobook but it still doesn't look normal.— Vchimpanzee • talk • contributions • 21:08, 27 October 2016 (UTC)[reply]

Its likely that the machine defaulted to a lower resolution. I can't really tell you how to change it back without knowing the actual operating system but there should be an option in the Control Panel. uhhlive (talk) 21:35, 27 October 2016 (UTC)[reply]

Control panel. Right. The people that work at the library would have to do that. I'll check the same computer next week to see if it's fixed.— Vchimpanzee • talk • contributions • 23:04, 27 October 2016 (UTC)[reply]

October 28

How do I use vi on the new macbookpro without an escape key?

175.45.116.104 (talk) 05:33, 28 October 2016 (UTC)[reply]

Ctrl-[ is equivalent to Esc. Assuming that Macs have a Ctrl key. LongHairedFop (talk) 09:59, 28 October 2016 (UTC)[reply]

The touch bar is reconfigured by the keyboard-focus-owning application. Presumably the terminal emulator application will put an ESC key on it, in the normal place. In Apple's developer introduction to the Touch Bar API they show an app with just that. Given how heavily vi uses ESC (I can't think of any program that routinely uses it as much) it may prove to be a bit annoying for the key to lose the tactile feedback of a physical key. -- Finlay McWalter··–·Talk 12:22, 28 October 2016 (UTC)[reply]

The vim wiki has been recommending avoiding the escape key since at least 2002: http://vim.wikia.com/wiki/Avoid_the_escape_key --Guy Macon (talk) 12:57, 28 October 2016 (UTC)[reply]

Another solution: http://www.jeffgeerling.com/blog/2016/apple-giveth-and-apple-taketh-away-escape-key-macbook-pro --Guy Macon (talk) 13:00, 28 October 2016 (UTC)[reply]

I use Mac Book Pros ... quite extensively. I am also an avid vi enthusiast. For the uninitiated, the escape key is very important for users of the vi text editor; the new Mac Book Pro, announced yesterday, has removed the Escape Key and replaced it with a digital key row called "Touch Bar." Most mortals who will use Apple's new Touch Bar equipped Mac Book Pro don't need to worry - the Touch Bar's escape key will "just work," in proper Apple fashion.

Indeed, it is wise to learn about the key-chord "ctrl-[" which will escape to the vim command-line. Ctrl+[ provides an escape-sequence to the escape-key. This is useful anyway - there are conditions on any computer where you might need an alternate key sequence.

When you are using a Mac equipped with Touch Bar and you are using vim, the Escape key is always available on the Touch Bar's virtual key layout, where you would expect it to be. This was actually described in the full Apple presentation yesterday - the October 2016 event. The Touch Bar's key layout depends on the application you are using, and there is even special support for Terminal.app.

If you use gVim, you might opt to use the UI menus in certain circumstances - but if you use gVim, you aren't really a keyboard-shortcut fanatic, are you?

Nimur (talk) 16:52, 28 October 2016 (UTC)[reply]

I'm not sure how that last bit follows. I use gvim, and hardly ever use the mouse with it. I prefer it over straight vi for what you can say are fairly trivial reasons, I suppose: I like that it spawns a new window, so that I can keep working in the window I started it from, and I like the colors better (sure, I could probably configure that in .vimrc, but why should I bother?). --Trovatore (talk) 19:11, 28 October 2016 (UTC)[reply]

That's fair. The real take-away is that the unique and specially-designed Touch Bar behaviors that apply in Terminal.app do not automatically occur in gVim (because gVim is not running inside Terminal.app).

The escape key, however, is available in both cases.

I am extraordinarily happy to see that developer documentation was published this morning, so all of the officially-supported behaviors are now committed to the public, by way of published API.

Nimur (talk) 21:20, 28 October 2016 (UTC)[reply]

October 29

Malfunctioning Windows 10 on HP Pavilion

I recently bought a new HP Pavilion with Windows 10 OS. I understand now why MS has been pushing Windows 10 on the public free of charge. The OS is full of ads. Some of that I have been able to remove. Then there are two major problems. A message for updates comes in from MS and I click OK. The system begins to update, proverbial white dots begin to roll around a small circle, I can see the percentage of what has been done, until it reaches 70 or 71%. Then the progress stops and after 40 minutes or so the OS begins to undo the changes after saying that update could not have been completed. It's happened 5 times already, last time this morning. It take an hour for the whole procedure. It is irritating and offensive.

The second problem is that many windows I invoke (open) get frozen on the desktop, like IE, FireFox, etc. It drives me nuts. No button will respond to any click until I invoked the Task Manager with Ctrl+Alt+Del. Today is the first time when even this drastic intervention stopped working.

So, I have two serious problems. I wonder if anybody could comment on them.

I also have a Linux Ubuntu machine. It works like a clock. Very simple and effective. MS has packed this Pavilion with bizarre features nobody needs, like Cortana. I tried to uninstall Cortana but it is irreducible. How to remove Cortana? I am about to join Microsoft hate crowd. --AboutFace 22 (talk) 17:57, 29 October 2016 (UTC)[reply]

The first step should always be downloading and creating Windows 10 insallation media (See [ https://www.microsoft.com/en-us/software-download/windows10 ]), formatting the hard disk, and doing a new install without the stuff HP adds. Be prepared to spend some time waiting as windows installs updates.

Next you should remove the Microsoft-added bloatware. See [ http://www.makeuseof.com/tag/easily-remove-bloatware-windows-10/ ] or [ https://www.hackread.com/windows-10-is-spying-on-you/ ] to do this manually.

Finally, you might consider using Spybot Anti-Beacon. See [ https://www.safer-networking.org/spybot-anti-beacon/ ]

There are other tools that claim to do similar things:

[ https://www.whatswithtech.com/how-to-stop-windows-10-from-spying-on-you/ ]

[ http://neurogadget.net/2015/08/20/windows-10-privacy-tools/13016 ]

[ http://www.ghacks.net/2015/08/14/comparison-of-windows-10-privacy-tools/? ]

[ https://bgr.com/2015/08/14/windows-10-spying-prevention-privacy-tools/ ]

--Guy Macon (talk) 18:46, 29 October 2016 (UTC)[reply]

THANK YOU VERY MUCH. I APPRECIATE IT. --AboutFace 22 (talk) 00:49, 30 October 2016 (UTC)[reply]

"Hot air balloon problem"

I just came up with this problem and am wondering about its computational difficulty (as in, its worst-case runtime).

A hot air balloon pilot wants to go from point $A\in \mathbb {Q} ^{n}$ to $B\in \mathbb {Q} ^{n}$ . There is a function $\mathbf {v} (h):\mathbb {Q} \to \mathbb {Q} ^{n}$ which gives the wind vector at height h (here, "height" is not a position parameter, but instead, considered as just a parameter the pilot can increment/decrement - the height will not change if the pilot does not decide so). Because weights are a finite resource, the pilot can only move up a given number of units $K_{up}\in \mathbb {Q} ^{+}$ n times, and can only move down $K_{down}\in \mathbb {Q} ^{+}$ m times. Every minute, the pilot has three choices: go up by K_up, decrementing his n "up" movements, go down by K_down, decrementing his m "down" movements, or maintain the current height, which implies maintaining the existing velocity (for simplicity, assume v is time independent and depends only on height). Each minute, regardless of the decision, the velocity vector is added to the current position (so the vector is always in units of position per minute). Assume that height changes are fast enough such that one can ignore the effect of winds between the starting and ending heights for every height change. The decision problem then is, can the pilot make this journey? Formally, is there a sequence of height increments starting from height 0, as described above, such that the sum of all the resultant velocity vectors is the position vector from A to B?

This problem is clearly in NP because any solution could be easily verified by just walking the proposed solution sequence. But is it in P, or is it NP-intermediate or something?--Jasper Deng (talk) 19:06, 29 October 2016 (UTC)[reply]

If I understand this question correctly. Your asking about forecasting a flight path and thus being able to choose altitude/wind currents rather than using app like [1] to log your flight path/track flown. A bit like being able to fly an aerial route map.--Aspro (talk) 20:45, 29 October 2016 (UTC)[reply]

@Aspro: No, it should've been clear that this is a theoretical computer science problem I just came up with. It has many unrealistic assumptions that would preclude its use in practice.--Jasper Deng (talk) 22:12, 29 October 2016 (UTC)[reply]

Assuming there is a finite number of heights, then all the paths will be a linear combination of the f(v) values. Which ones of these can get you from A to B can then be solved as a simultaneous linear equation, that will give the times that you spend at each height. This will take polynomial time. Note that there may not be a single solution. So then you have to intersect your constraints on n and m. This will result in a more limited simplex that will contain all the answers - possible routes. If you are limited to doing this on minute boundaries, and not at arbitrary times, then you have more contraints, and will likely have no solution. But in anycase this should be solvable or proved you can't do it in polynomial time. Graeme Bartlett (talk) 01:03, 30 October 2016 (UTC)[reply]

The existence of such a linear combination is necessary, but not sufficient for a solution. The way the problem is constructed, one cannot "jump levels", i.e. I cannot go from height N to N + 2K_{up without first passing through N + K_{up or other intermediate levels (depending on K_down and K_up and whether they're equal). I'm not sure you could formulate these constraints as linear ones, especially when K_up is not the same as K_down.--Jasper Deng (talk) 01:27, 30 October 2016 (UTC)[reply]
I am assuming that you spend no time in your transitions of height. The possible levels should be n×m or less. Just being able to move one up or one down at a time is just yet another constraint. It would result in a smaller intersection of the simplexes with less than n×m dimensions. Read Linear programming, and Simplex algorithm. If it is an Integer programming problem, then it becomes much tougher. Graeme Bartlett (talk) 01:51, 30 October 2016 (UTC)[reply]
That assumption is correct. I have learned integer linear programming in the past but am unsure of its applicability here. To be clear, yes this is an instance of integer programming, because we are really looking at an integer lattice generated by the different values of v, since one may not take nonintegral linear combinations here. All known algorithms for a general ILP run in at least pseudopolynomial time (since ILP is NP-complete). An $O(mn)$ solution would still be only pseudopolynomial in m and n. Even if we did not restrict it to integers, I'm not sure of how one could encode the m and n constraints in only polynomially many inequalities.--Jasper Deng (talk) 04:12, 30 October 2016 (UTC)[reply]
Your problem-setup assumes perfect a priori knowledge of the field (the wind function at all positions), correct?
Your algorithmic running-time bound - and the result of your decision-problem - depends entirely on the properties of this field. If the field is entirely unconstrained, the decision is much harder - you might have to traverse every possible path, which is a graph search in dimensionality n × m × h. (This is not a realistic model of normal wind, but it's how you described the problem: wind can cross other flow lines and speeds can vary without constraint). If the field is uniform at all positions, the decision problem is easy, almost trivial. If there is some constraint, like a smoothness constraint, on the field, there might be a more efficient way to reduce the span of your search space.
I think I'd begin by looking at our article on graph connectivity to see what prior art exists. It's a safe bet to say that your problem is a special-case of some already-published theoretical work. We just need to figure out what obtuse mathematical keyword describes your graph and its connectivity property.
Nimur (talk) 13:53, 30 October 2016 (UTC)[reply]
The wind field has no smoothness or other conditions imposed on it, but yes, you know it as a given. I wanted to avoid thinking of it as a graph problem: a graph to represent it would ignore the vector arithmetic aspect of this problem, and IMO would not be easier than an integer programming formulation, as described above.--Jasper Deng (talk) 19:20, 30 October 2016 (UTC)[reply]}}

Because the question is "can the pilot make the journey?", I would place it in P, easily calculable using lazy evaluation. If, instead, you asked "what is the optimal journey?", I would not place it in P because it is unlikely that there is a linear solution that finds the optimal journey. Nearly all problems can be divided like this. The classical Traveling Salesman is hard because it asks for the minimal path. If, instead, you asked for any path, it would be an easy problem. 209.149.113.4 (talk) 11:33, 31 October 2016 (UTC)[reply]

@209.149.113.4: And your algorithm is? Lazy evaluation is not relevant here. And also, this asks for a solution within the aforementioned bounds on m and n height changes - therefore, one could easily restate the problem here as an optimization problem w.r.t. either of those variables. Also, a pure decision problem in NP is also generally not known to be in P - 3-SAT makes no mention of optimization at all and is NP-complete.--Jasper Deng (talk) 15:36, 31 October 2016 (UTC)[reply]

USB 3.0 Hub ports

Moved from Wikipedia:Reference desk/Miscellaneous § USB 3.0 Hub ports

– 47.138.165.200 (talk) 22:26, 29 October 2016 (UTC)[reply]

1) What do call a hub box that consist of a Micro SD card slot, memory card slot along with few USB insertion ports? An example of a design or just the name of what it is called as a whole, is sufficient.

2) This point is irrelative to the above and is as follows:

My Laptop is from the year 2012 or so. I think the USB box port[s] attached is of v2.0. I wonder if v3.0 wired products will function as it should thereafter connecting to this v2.0 box, or, do I require a USB 3.0 box in order for a v3.0 wired product(s) to function efficiently? — Preceding unsigned comment added by 103.230.104.22 (talk) 19:08, 29 October 2016 (UTC)[reply]

If I understand your description correctly, it's generally called a "USB memory card reader" or something along those lines. USB is designed to be forwards- and backwards-compatible. Any USB 3.0+ device should work with a USB 2.0 port of the same connector type, but speeds will be limited to 2.0 speeds. --47.138.165.200 (talk) 22:37, 29 October 2016 (UTC)[reply]

I would call it a memory card reader with USB3.0 hub (or similar). That seems to be what other sites call it too [2] [3] [4]. (Last one is a 2.0 only.) Nil Einne (talk) 01:57, 30 October 2016 (UTC)[reply]

Any idea why/when the DC Power Plug should be used?; I'm happy with Nill's Point no: 1. However, I'm looking for more ports, 10+ or so. 103.230.105.20 (talk) 19:14, 31 October 2016 (UTC)[reply]

Again assuming I'm interpreting you correctly, the power plug is to provide power to the ports in the USB hub. Typically the hub can operate with or without this; you only need it if you plug in a USB device that draws a lot of power. --47.138.165.200 (talk) 03:08, 1 November 2016 (UTC)[reply]

.iso files don't get burned

I have a Windows 7 laptop. When I click on an .iso files the system shows it's readiness to burn it to blank disk. I put in a blank DVD and trigger process. But after all the show that disk is being written to, it turns out that disk is blank (though a closer visual inspection of DVD shows that slight darkening of tracks that for a moment makes one believe that data has been written to it.) But put it back in computer and it's empty. Why so happens ? Some overlook on my part in contemplating the process ?210.56.108.118 (talk) 15:48, 30 October 2016 (UTC)[reply]

Did you write click on the iso, select burn, and then select the destination drive? Graeme Bartlett (talk) 03:46, 31 October 2016 (UTC)[reply]

October 30

Bit and Qubit Register

Two part question:

I'm not really sure what a bit register is or what is so special about it. It just seems like a bunch of bits in a row! Could someone explain somewhat intuitively what it is and why it is important?
Going on with the bit register, I'm reading about quantum computing and a "qubit register" was one thing that came up. What is this/why is it so special? Again, this just seems like a bunch of qubits in a row. I do know that it can be written like |A>|B>|C>...|Z> or |ABC...Z> where A, B, C,...,Z are qubits, but I don't really understand intuitively what is going on here.

Any help would be appreciated, thanks! Hnerd (talk) 19:58, 30 October 2016 (UTC)[reply]

You can look at our articles Processor register and Quantum register, though they may not be helpful. Hardware register and flip-flop (electronics) may be more useful. You are correct in that they are a bunch of bits stored in a row. They usually have facilities to do things with the bits, such as shift register or other bitwise operations. They will have ways to load, and store values, ways to test what is there, and likely ways to clear them to all zeros. Graeme Bartlett (talk) 03:40, 31 October 2016 (UTC)[reply]

Waiting for USB-C

I'm thinking about buying a high-end Lenovo X1 Yoga laptop (the model with the OLED screen and 16 GB RAM (which unfortunately only comes with the i7-6600U which I wouldn't choose if I could get more than 8 GB on this machine with an i5, but the RAM is soldered and configurations are limited)), and was wondering if I should really be waiting until the next gen comes out with a USB-C port. Can you guys point me to 1) a site that predicts when the next X-1 Yoga will be available based on Lenovo's release cycle and 2) a description of what I might be missing in a year or two by having a laptop with three USB 3.0 ports but no USB C. It seems that the big USB-C advantage is having a single cable type and single port type for multiple purposes. Is this all just a matter of convenience, or is there something that I will likely be wishing I could do a year or two from from now, "If only I had USB-C."? -- 66.203.139.164 (talk) 22:26, 30 October 2016 (UTC)[reply]

Yes, it's mostly convenience, as well as future-proofing. USB Type-C is an attempt at making "one cable to rule them all" for modern external communications buses. You likely won't miss much unless you're devoted to getting all the latest bleeding edge gizmos. At most you'll need a hub or adapter, if you get something that only has a USB Type-C connector and want to connect it to your laptop. --47.138.165.200 (talk) 03:23, 31 October 2016 (UTC)[reply]

See also this and this. --76.71.5.45 (talk) 05:34, 31 October 2016 (UTC)[reply]

November 1

Bypass computer's soundcard while using headphone amp?

So I just bought a USB headphone amp, the Fiio A3. Perhaps I naively assumed I could link it to the computer via USB and it would somehow bypass the computer's onboard sound card and just forward it to the amp, but that appears to not be the case? Looks like the only way is to run an 8th inch cable out of the computer's headphone jack into the aux-in of the amp? That's dumb... Is there a way to forward the audio output via USB? Thanks! NIRVANA2764 (talk) 16:03, 31 October 2016 (UTC)[reply]

I can't find a definitive manual for this, but everything I'm seeing on line suggests it's just a headphone amp with a battery, and that the microUSB port is solely for charging the battery. If you wanted to bypass the onboard sound card, you would have needed to buy a USB external soundcard. -- Finlay McWalter··–·Talk 16:27, 31 October 2016 (UTC)[reply]

Do you think the external soundcard bit would make a world of difference? NIRVANA2764 (talk) 16:29, 31 October 2016 (UTC)[reply]

For the average person (youtube, spotify, games), for output, probably no. If you wanted to drive some fancy multi-channel home theatre thing, maybe, I don't know. If you were involved in amateur or professional musical or audio production or editing (e.g. music recording, webcasting) where you needed to hook up decent microphones or musical instruments (often with an XLR or instrument-cable connection) then you want a USB audio interface like a Focusright or a Presonus, and not a "soundcard" per se. -- Finlay McWalter··–·Talk 16:38, 31 October 2016 (UTC)[reply]

Cool, thanks. I'm just gonna be using it with my laptop playing mp3s through some Shure SRH440s or Grado SR60s, just wanted something to make the sound louder and beefier but now I'm wondering if I should return this and pay a bit more for something with a DAC... NIRVANA2764 (talk) 16:43, 31 October 2016 (UTC)[reply]

Most evidence I've seen based on actual scientific inspired testing rather than flawed (i.e. non blind) "audiophile" testing or anecdotal reports suggests nowadays the DAC in most computers is good enough and the audiopath is likewise clean enough, so a good enough amp/driver is all you're likely to need (if that). Whether your device qualifies I have no idea. In other words, while it may seem nice to keep the signal digital as long as possible, ultimately it's probably better to ensure the device you have is sufficient rather than worrying about whether it has digital or analog input. The Hydrogen Audio forums [5] is a good place to get advice on consumer products largely free from the nonsense that seems to pervade a lot of audiophile groups. While it mostly focuses on the digital side of things, there is a place for discussions of hardware. Note that while USB sound cards are common, you could also use a device with HDMI input or TOSLINK/coax S/PDIF assuming your computer has them (I'm assuming it has at least one). Nil Einne (talk) 01:57, 1 November 2016 (UTC)[reply]

If you really want to go the DAC route, I noticed some discussion here [6] although it's mostly concentrated on speakers. I also noticed the FiiO D3 (D03K) seems to get good comments on those forums e.g. [7] [8], and it seems to be quite cheap although I don't know if the amp is good enough for headphones (which again is the main factor since it's quite difficult to design a DAC which isn't good enough to be come irrelevant nowadays). For pure amps the open source Objective2 headphone amp and CMoy seem to be interesting choices [9] although if you're not making them yourself, I'm not sure if they're necessarily and cheaper or better than more commercial products if you concentrate on the actual performance of these products rather than the hype and don't get suckered in my products which aren't actually any better than cheaper alternatives. Nil Einne (talk) 02:29, 1 November 2016 (UTC)[reply]