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July 2

interference to heart rate monitor

There is nothing wrong with my watch (forerunner 305). I am just wondering, will the heart rate monitor work when I am using the elliptical in the gym? It is a heart rate monitor that is worn below the chest, and pairs with the watch (it is not attached to the watch). The elliptical is about 2-2 1/2 feet from a television. — Preceding unsigned comment added by 99.146.124.35 (talk) 02:19, 2 July 2013 (UTC)

I think it's very unlikely that a TV monitor will generate strong enough electric fields to mess up a heart rate sensor that you wear on a strap that goes around your chest. Are you having problems? Looie496 (talk) 02:27, 2 July 2013 (UTC)

As to whether the sender in the chest strap will be understood by the receiver in the elliptical machine, the answer is "maybe". There's a variety of wireless protocols that such equipment uses - ANT+ seems to be the dominant (the closest there is to a standard), but other systems use other schemes, some of them proprietary. The Garmin Forerunner article suggests they all do ANT+; you'd have to see what the brand of elliptic machine uses. I have gotten a Target Fitness band working with a Life Fitness bike, but neither has markings as to how this worked. In that case, a Bluetooth-like "pairing" paradigm doesn't seem to hold, as my heartrate was shown in the two adjacent bikes too - so presumably each bike was picking the strongest radio signal, if any. Sensibly, the Life Fitness equipment would ignore the radio signal and use the signal from its contact heartbeat sensors (if there was one) - so the people riding those adjacent bikes could grab the handlebars and override the display of my heart rate with theirs. -- Finlay McWalterჷTalk 10:17, 2 July 2013 (UTC)

HP 9845C screenshots?

At the homepage about HP 9845C. There are some really nice pictures [1], [2], and at the demo [3], [4], etc. Is there any free versions of these? Electron9 (talk) 13:10, 2 July 2013 (UTC)

Wow those are pretty neat! So you mean free versions of those exact pictures? I don't think that would be possible - you would have to claim fair use. There might be similar images that are free but those, probably not. --Yellow1996 (talk) 16:10, 2 July 2013 (UTC)

⟍⟍⟍⟍⟍⟍⟍⟍⟍⟍⟍

What do we call this character? ⟍ is a redlink, as is Box (typography). 2001:18E8:2:1020:5DD6:98CF:4B3B:E815 (talk) 13:28, 2 July 2013 (UTC)

mathematical falling diagonal -- Finlay McWalterჷTalk 13:31, 2 July 2013 (UTC)

Hm. On my screen, it's a little rectangle, not the character that displays on your link; I guess I don't have the right font. I was meaning to ask: what's the "official" term for the little box that displays when you don't have the right font installed? 2001:18E8:2:1020:5DD6:98CF:4B3B:E815 (talk) 13:35, 2 July 2013 (UTC)

Exactly. More generally, if a page contains a unicode character that isn't represented by an available font, your browser will draw a placeholder box. Some browsers (e.g. Firefox) will show the hexadecimal value of the character's codepoint (27CD in this case) inside that box, so even if you can't see what the character is supposed to look like, and it's possible to search unicode info sites like the one I listed above for the character by its code. See fallback font and Unicode's "Display of Unsupported Characters" advice. It doesn't render correctly for me either, btw. -- Finlay McWalterჷTalk 13:43, 2 July 2013 (UTC)

So is the box image officially a "placeholder box", "missing glyph", a ".notdef glyph", or something else, or does it not have an official name? 2001:18E8:2:1020:5DD6:98CF:4B3B:E815 (talk) 13:47, 2 July 2013 (UTC)

Beyond those there's also "substitute character", and uncode suggests using U+FFFD � "replacement character" (see Specials (Unicode block)). -- Finlay McWalterჷTalk 13:50, 2 July 2013 (UTC)

Freezing on a Mac

I have a MacBook Pro and recently have experienced freezing when watching films with DVD player and when watching videos or listening to music in iTunes. With the music in iTunes, there is just silence for a few seconds, before the music eventually starts playing again, at the same point where it stopped. With the other two problems, the video freezes but the audio tends to continue. Can anyone suggest anything? A similar issue happened to me a while back with just iTunes and it was solved by repairing disk permissions but that hasn't helped this time. Thanks. meromorphic [talk to me] 20:43, 2 July 2013 (UTC)

Have you tried reinstalling your video drivers? --Yellow1996 (talk) 20:34, 3 July 2013 (UTC)

You really don't do that on a Mac ;-). Check if the Activity Monitor shows some unusual activity. Sometimes a rogue process uses too much system resources. --Stephan Schulz (talk) 20:44, 3 July 2013 (UTC)

Ah - I see! I was actually going to affix "I was hoping that an actual Mac user would respond, but..." to my answer; and luckily for the OP, one has! ;) --Yellow1996 (talk) 21:10, 3 July 2013 (UTC)

Well, I'm more of a UNIX head, but PowerBooks/MacBooks have for a while been the best UNIX laptops one could buy. Not modern Ultrabooks with Ubuntu come close, but not yet close enough... --Stephan Schulz (talk) 21:55, 3 July 2013 (UTC)

How much RAM do you have? How much free space on your startup drive? Are you running a lot of other programs at the same time? It kinda sounds like your system is thrashing. --Navstar (talk) 19:36, 5 July 2013 (UTC)

July 3

What are these computer games?

First was on an Atari, I think. You play this guy whose spaceship crashes on a planet. The very first scene involves swimming out of your wrecked spaceship before some tentacles grab you. Then you are up on the shore of the lake. You have to move fast or the tentacles will reach out of the water behind you and drag you back into the water. There are some kind of horrible snake/worm things in this first scene as well.

The second was on the Amiga. It is a vertical scrolling platform game. I think it is set on Mars and you play one of two little creatures who are searching for water. There are signs everywhere saying "H2O".

Any ideas? Horatio Snickers (talk) 10:59, 3 July 2013 (UTC)

I'm amazed that I'm stumped for the first one because I am really familiar with Atari games... and is the second one Flood? --Yellow1996 (talk) 17:54, 3 July 2013 (UTC)

The first one: Another World? (I had the Press Start for Game Over trope open some weeks ago, and searching for "tentacle" threw it up.) - ¡Ouch! (^{hurt me} / _{more pain}) 08:00, 4 July 2013 (UTC)

Another World - that's the one! I'm pretty sure the first one wasn't Flood, though. It doesn't look similar to me. If it helps, I think the version I played was a demo given away for free on an Amiga magazine but I have no idea when. Thanks! Horatio Snickers (talk) 15:28, 4 July 2013 (UTC)

Every Amiga game ever released - should be on there somewhere! :) Do you remember anything about the title of the second game? That might make finding it a lot easier than sifting through all those lists (they're in alphabetical order); either way, it's somewhere on that site. --Yellow1996 (talk) 16:30, 4 July 2013 (UTC)

I've got it! Flip-it & Magnose: Water Carriers from Mars, apparently! Had a look at that site but there's a lot on there - did a search for "amiga mars water" in the end and it popped up. Thanks for all your help! Horatio Snickers (talk) 10:26, 5 July 2013 (UTC)

You're very welcome! I'm glad you found it! :) --Yellow1996 (talk) 17:39, 5 July 2013 (UTC)

Searching in Windows Explorer

Is it possible to limit searches in Windows Explorer (on Win7) to exact file-name matches? By default when searching for, say, file.ext, it seems to find anything that matches *file*.*ext* Rojomoke (talk) 16:16, 3 July 2013 (UTC)

Never mind. Double quotes are what I needed. Rojomoke (talk) 16:27, 3 July 2013 (UTC)

Speaking on the same subject, is there any way to get Windows 7's search to behave/imitate like Windows XP's search function? I find XP's to be much more powerful and requires little/no confusing syntax (since 7's is all in one search box). -- 140.202.10.134 (talk) 16:43, 3 July 2013 (UTC)

This tutorial may be of some help. --Yellow1996 (talk) 17:48, 3 July 2013 (UTC)

In my experience, the Win7 search is unreliable, even if you follow the above tutorial. I either use Super Finder XT (if I want a GUI) or Grep under Cygwin (seeing as I'm from a Unix background). --TrogWoolley (talk) 22:02, 3 July 2013 (UTC)

I, too, find Windows 7's search to be as good as useless. I highly recommend Mythicsoft's FileLocator. The Lite version is free and still does a better job than Windows. The Pro version costs (US $39), but gives extra functionality - in my opinion well worth paying for (if for no other reason than to support programmer's who develop good software like this). Mitch Ames (talk) 13:06, 8 July 2013 (UTC)

Need a complicated, but really cheap site.

A non-profit is looking for someone to create a rather complicated web site. My guess is that it would take an experienced programmer at least 3 months to create it. As the budget is really small (a few thousand dollars at most) I was wondering if there are reliable websites to find freelancers directly at "Bangalore rates", without having to pay for managers, etc. I could do the managing, but I don't have 3 months holiday at hand.. Any ideas? Joepnl (talk) 23:04, 3 July 2013 (UTC)

You can always have a look at guru.com - my brother really swears by them, but I'm rather skeptical, personally. I expect that any money you try to save by going the cheap route, you'll have to pay for later in trouble, and most likely it will require quite a bit of managing. 3 months to create a website sounds like a pretty damn complicated website, too - do you have any reasoning behind this estimate or did you just ballpark it? 64.201.173.145 (talk) 02:33, 4 July 2013 (UTC)

Perhaps if you can describe the complexities they want, we can suggest simpler and more economical ways of accomplishing the same thing. For example: Do they want a zoomable, rotating Earth as a way to zoom in to any of their sites ? How about a non-zoomable, pickable flat map instead ? StuRat (talk) 08:10, 4 July 2013 (UTC)

Thanks both, I'll have a look at guru.com. It's not technically complicated, but there are just al lot of tables, screens, buttons, etc. Joepnl (talk) 13:26, 4 July 2013 (UTC)

Downloading and editing portions of a NSA video on polygraphing

There is an NSA-produced video on the polygraphing process:

• Video: http://www.nsa.gov/media_center/careers/video/Polygraph/index.html
• Transcript: http://www.nsa.gov/media_center/careers/video/Polygraph/Transcript.html - http://www.webcitation.org/6Hqa0BJZZ - http://archive.is/CSpsI

While an NSA-produced video is public domain, it also uses very short excerpts of footage from copyrighted TV shows: Meet the Parents and The Simpsons So, does this mean, for it to be posted on the Commons, the footage of the TV shows has to be cut out (I assume yes, but just making sure)? How should I download the video and do the editing? WhisperToMe (talk) 23:36, 3 July 2013 (UTC)

IANAL, but I would assume your notion of having to cut out the copyrighted material would be correct. As for downloading the videos, I have gotten great use out of DownloadHelper for Firefox. For the editing (the cutting-out of the copyrighted material) any free movie making/editing software should do (though Windows Movie Maker generally doesn't play nice with the types of files you'll get from DownloadHelper and similar addons - you'll need a converter.) --Yellow1996 (talk) 16:38, 4 July 2013 (UTC)

July 4

Memory not entirely recognized by laptop

I have an eMachines E627 laptop, and I have two 2GB memory cards installed (which, according to the technical specifications of the system, is the maximum amount of memory permissible for this model). However, it seems that only the memory installed in the inner slot gets recognized by the system, whereas the memory installed in the outer slot does not. I experimented with the system and determined that each individual memory card works fine when installed in the inner slot. Is this problem common? How can I get the system to recognize all 4GB of memory installed? 24.47.141.254 (talk) 02:43, 4 July 2013 (UTC)

What operating system are you using, and how are you determining that it can't see all the memory? RudolfRed (talk) 03:04, 4 July 2013 (UTC)

Also, have you checked if all 4GB is visible to the BIOS? WegianWarrior (talk) 03:49, 4 July 2013 (UTC)

I am using Windows 7. When I run setup at the beginning, BIOS shows 2048 MB of memory (instead of the expected 4096 MB), and the "System" function from my Control Panel shows 2.00 GB of memory (not 4.00 GB). During my experiments, I tried inserting one memory card into the outer slot and leaving the inner slot empty, and surely enough, the screen did not display anything when I powered up. 24.47.141.254 (talk) 05:08, 4 July 2013 (UTC)

If your BIOS does not recognize more than 2GB, there is no way the OS will be able to see it either. Not sure how to fix though, sorry. WegianWarrior (talk) 06:49, 4 July 2013 (UTC)

Try booting with RAM in the outer slot only. If it doesn't boot, the slot is probably broken. Also, try putting smaller modules in each slot or just the inner slot if you have any available. -- BenRG 23:31, 4 July 2013 (UTC)

I would go to www.crucial.com with that computer and have it scan your computer, and let it tell you how much RAM it sees and how much RAM it can take. I looked for your model there but I didn't find it. But I've found Crucial.com to be reliable about memory. Bubba73 ^{You talkin' to me?} 03:29, 5 July 2013 (UTC)

Or get a program like Speccy: http://www.piriform.com/speccy - it tells you that information. Bubba73 ^{You talkin' to me?} 03:32, 5 July 2013 (UTC)

Calculating Pearson correlation coefficient with Python

def pearson_correlation(a,b): # Python 3
    if len(a)!=len(b):
        raise ValueError('samples are of unequal size')
    mean_a=mean_b=0
    for i,j in zip(a,b):
        mean_a+=i
        mean_b+=j
    mean_a,mean_b=mean_a/len(a),mean_b/len(b)
    x=y=z=0
    for i,j in zip(a,b):
        x+=(i-mean_a)*(j-mean_b)
    for i in a:
        y+=(i-mean_a)**2
    for j in b:
        z+=(j-mean_b)**2
    return x/(y*z)**(1/2)

This function takes two samples as two lists and returns the Pearson correlation coefficient of them. Is there any thing wrong with it? Czech is Cyrillized (talk) 02:56, 4 July 2013 (UTC)

I see some possible problems:

1. The usual way to make multiple assignments on one line in Python is

mean_a, mean_b = 0,0

I think an expression like

mean_a = mean_b = 0

is assigning mean_a to the result of the expression "mean_b = 0" - although in this case that could be 0 anyway, so this might make no difference.

2. Be very careful with integer division in Python. One of the oddities of Python is that any arithmetic expression that includes only integers returns an integer value - so 1/2 will return 0, whereas 1./2 will return 0.5 because 1. is a float not an int. So your final line

return x/(y*z)**(1/2)

will always return 1 (I think) because the value of 1/2 is 0. You could try

return (float(x)/(y*z))**(0.5)

or you could use the sqrt function, but you have to import that from the math module. And if your lists a and b only contain integer values, there could be a similar integer division problem when you are calculating mean_a and mean_b. A good rule of thumb is that wherever you have a division expression that you expect to return a non-integer value, convert the numerator or denominator to a float to force the result to be a float.

3. Not a problem as such, but the loop where you sum the values in lists a and b is not necessary because Python has a built in sum function that returns the sum of values in a list.

Gandalf61 (talk) 11:40, 4 July 2013 (UTC)

If I understand your mean_a, mean_b calculations properly, and taking into account Gandalf61's wizardly advice about floats, the calculation of those two can be simplified to:

  mean_a = float(sum(a))/len(a)
  mean_b = float(sum(b))/len(b)

turning 5 lines into two (and to my mind being much clearer). edit yeah, I didn't read Gandalf's last point before posting.-- Finlay McWalterჷTalk 12:48, 4 July 2013 (UTC)

You can also change those calculations for x, y, z into sums on list comprehensions, like

x= sum([(i-mean_a)*(j-mean_b) for i,j in zip(a,b)])

- although that's not such an obviously clearer piece of code. -- Finlay McWalterჷTalk 13:01, 4 July 2013 (UTC)

• Assignment isn't an expression in Python; x = y = 0 works by special dispensation, not because of expression rules. So it's evidently an officially endorsed way of doing multiple assignment (and it's pretty common in Python code).
• There's a near universal convention of putting spaces after commas in Python code. You should follow it for readability's sake. It's also good practice to put spaces around infix operators.
• In Python 3.x, the / operator returns a floating-point result even if the arguments are integers, and // does integer division (as described in PEP 238). Since Python 2.2 (released in 2001), you can write from __future__ import division at the top and then just say sum(a) / len(a), etc. This is a good idea for forward compatibility reasons.
• Finlay McWalter's sum([...]) can be shortened to sum(...) as of Python 2.4 (released in 2004).

-- BenRG 23:27, 4 July 2013 (UTC)

Why cant Graphics processing units keep up with Central processing units?

"Top" GPUs like Tahiti XT in AMD "Radeon 7970" and "7990" series Videocards or as GPU from Nvidia (GK110) in "GeForce GTX 780" or "Titan" labled Videocards work on a frequencies of 900-1000 MHz. Same time "TOP" CPUs from Intel like "core i7 3770K" or "core i7 4770K" run at 3500 MHz and additionally are known to overclock to near 5000 MHz as are CPU from AMD like "AMD FX-4350" starting even from 4200 MHz. Same with "big professional" brands like SPARC T5 (3600 MHz). Why is it that customers willing to pay beyond $ 1000 for a Nvidia "Titan" Videocard only get a 900 MHz GPU and one buying a 3500-4500 MHz CPU like "core i7 4770K" only has to pay $ 300. Also why exactly are GPUs not also clock atleast near with maybe 3000 MHz? --Kharon (talk) 07:18, 4 July 2013 (UTC)

Roughly, because "clock speed" is a really bad measure of performance. See Megahertz myth. Graphics cards do different things per clock, and they can use massive parallelism. In fact, GPUs are much ahead of CPUs in pure processing power, and there is an increasing trend to tap into that performance for general purpose computing. See General-purpose computing on graphics processing units. The high end Radeon Sky 900 is rated at nearly 6 TeraFLOPS, while the best multi-core i7 CPUs are stuck more than an order of magnitude behind that. --Stephan Schulz (talk) 08:29, 4 July 2013 (UTC)

Nonetheless it's an interesting question why GPUs tend to be clocked slower than CPUs. (I don't know the answer.) -- BenRG 23:29, 4 July 2013 (UTC)

Because clock speed is not the limiting factor for most GPU workloads. Unlike a typical CPU workload, there is much lower temporal locality in a GPU's operations. The little temporal locality that does exist already gets exploited by using a specialized pipeline. So, with little data reuse, the data transfer rate dominates performance. A very small parallel work-load, say four 32-bit integers wide, requires 128 bits per transaction. A fully-utilized GPU will therefore input and output 128 bits per clock - or, at 1 GHz, will require 256 GBits/sec of available bus bandwidth. No system-bus in the world can sustain that data-rate, at least not in 2013. So, clocking the GPU faster means that the GPU is under-utilized, most of the time. This is unlike the CPU, where a small amount of data is reused over many computer instruction cycles, taking full advantage of the processor cache.

If you look at the structure of a modern GPGPU, you will see that the best effort solution to this problem is to allow the kernel programmer to manage the GPU cache memory in very customized way. When I worked on the Tesla S1070, there were some 16 kilobytes of what you might handwavingly call the L1 cache - and using the CUDA extension to the C programming language, the programmer allocated that memory to each processing kernel (i.e. to each processing unit). Even with this kind of fine-grained control, it was uncommon to get as high as, say, 16 instructions per word for a typical massive parallel calculation. Inevitably, the cache was never very useful, and memory transfer time from main GPU RAM and system RAM overwhelmingly dominated the total process execution time. My program, calculating the wave equation, would burst for a couple microseconds, cranking along at an instantaneous rate of a few gigaflops at a time... and then stall for hundreds of milliseconds waiting to copy the result back to system memory, and copy in new work. Getting "lots of flops" isn't too hard if you have a thousand cores running at a mere 1 GHz! One billion instructions require just one millisecond of work! And our 960-core S1070 is now four-year-old technology - today's GPUs have more cores! Keeping the GPU busy for more than one millisecond out of each second - now that is still a challenge!

In other words, even at a mere 1 GHz, the GPU is still too fast for the memory and system to keep up. Clocking it faster burns power and accomplishes no extra work - the GPU will simply be spending more time waiting in a pipeline bubble executing no-op instructions. You can read about even more recent GPGPU architecture details at Nvidia's website: http://nvidia.com/cuda . Nimur (talk) 01:54, 5 July 2013 (UTC)

Thank you Stephan Schulz and Nimur for your very informative answers. But i still dont get why they need 2000 "stream cores" running on 900 MHz instead of 500 cores running on 3600 MHz. That wouldnt demand faster memory controlers and cache on Die can run on 3.6 GHz in CPUs already. That would clearly make GPUs much cheaper. --Kharon (talk) 10:01, 6 July 2013 (UTC)

Not every modern GPU is a massively-parallel behemoth; some are smaller, cheaper, and perform differently - better on some benchmarks, worse on others. For example, Intel HD Graphics are smaller and cheaper than the flagship Nvidia GPUs, yet they perform well enough for many common applications. GPUs for mobile platforms are designed to handle typical mobile workloads, so they have fewer cores and emphasize energy efficiency. Or consider the Tegra 4, specifically on its capability to shuttle data between a GPU, a CPU, and an ISP; it intentionally blurs the boundary between CPU and GPU logic. So, there is a lot of variety in the available platforms; today's technology capability defines a price, power, performance design envelope; and market forces dictate that the products available to end-users cluster around the extreme edges of that design envelope. Nimur (talk) 21:38, 6 July 2013 (UTC)

How does solar model works

Do all scientists use computer simulations and solar models to calculate future for the sun or only certain groups of astrophysics does that. Because I have problem think concrete details that is why I thought [5] when scientist do solar model all the variables are well-written. I cannot tell when they guess on the variable they don't know. When astrophysics create solar model do they have to fill out the data entry they are require to fill out all the variables? How can they guess on certain variables if they have to fill in variables on the solar model? If they don't know they can just leave that entry blank. Do solar model require all variables to be fill out in order to run the simulation? Can these two documents I linked above have alot of errors, I can't tell because I am not a concrete thinker--69.233.254.115 (talk) 20:20, 4 July 2013 (UTC)

Both articles are not based on the very latest data; one is from 1993 and the other is from 1997. The intended audience is also very different: The first is published in ApJ, a very well respected scientific journal in which astrophysicists publish the results of their research, and uses language and assumes knowledge that other astrophysicists would be familiar with. The second has a more popularist style suitable for being presented in a lecture to university undergraduates and the wider public at an observatory.

As I found out at university, there is no one standard computer model of stellar evolution and each model is (or at least our model was) wildly sensitive to the input conditions. For most models some data is well known, some has pretty good estimates (within a small range of values), and other data can be widely different. However, most computer models will treat a blank value as zero, instead of "I don't know", unless it has specifically been written to account for this. While zero pressure in space isn't too bad an estimate, zero kelvin at the star's surface is a really bad estimate. Astronaut (talk) 18:29, 5 July 2013 (UTC)

Does how old the articles are really matters on how accurate the information will be? How will newer data make older data more accurate. How will people be able to study things more accurate just 16-20 years timeframe? Is it short time frame phases only 10-50 million years needs deeper studies. So some models can estimate well, and others can range widely. What happens if you write "I don't know" on input entries? in astronomical time scale 100 million years really is only a small fraction of timescale right.--69.233.254.115 (talk) 20:12, 5 July 2013 (UTC)

July 5

mouse malfunction?

A lot of times lately an a browser when I click to go back, it goes back two pages. I'm wondering if the mouse is sometimes sending two "clicks" instead of one. Is there a way to test the functions of a mouse? Bubba73 ^{You talkin' to me?} 14:50, 5 July 2013 (UTC)

Try a paint program; if it's somehow generating two clicks the paint program would show two blobs and not one. 87.112.233.132 (talk) 14:58, 5 July 2013 (UTC)

I don't have a paint program loaded, as far as I know. Bubba73 ^{You talkin' to me?} 15:12, 5 July 2013 (UTC)

try http://api.jquery.com/dblclick/ On the "demo", when you double click it changes color.190.60.93.218 (talk) 16:25, 5 July 2013 (UTC)

Or try a Google search: online mouse click counter. There are even games about how many times you can click. PrimeHunter (talk) 16:32, 5 July 2013 (UTC)

But that doesn't tells if he has clicked or doubleclicked, also on Windows at Control Panel>Mouse you can modify the time limit on where to send a doubleclick. 190.60.93.218 (talk) 16:41, 5 July 2013 (UTC)

OK, I tried that link above and sometimes it is doing a double click. Then I went to the control panel/mouse and set the double-click speed all the way "fast". I clicked slowly, and sometimes it took it as a double click, about one out of 5 to 15 times. So it must be either the mouse going bad (it is a good Logitec but several years old) or maybe some malicious software. Bubba73 ^{You talkin' to me?} 16:57, 5 July 2013 (UTC)

This seems to suggest it might be a messed up microswitch; though this appears to be a common problem amongst Logitec users. Try plugging it into a different PC and see if the problem persists. Though you may have to end up replacing it. --Yellow1996 (talk) 17:45, 5 July 2013 (UTC)

Resolved

I went ahead and bought a new mouse a short time ago, but I haven't started using it yet. Bubba73 ^{You talkin' to me?} 20:58, 5 July 2013 (UTC)

The new one is working fine, so that is what the problem was. Bubba73 ^{You talkin' to me?} 22:30, 5 July 2013 (UTC)

Can computers/programs/algorithms/functions explain or create other functions or algorithms?

Is it possible that computers can create or explain functions? Like a normal human (programmer) does it all the time, Humans can do many things like from writing, drawing (abstract), etc... How can a computer do it? 190.60.93.218 (talk) 16:19, 5 July 2013 (UTC)

Synthesizing a new algorithm is a common process. This is sometimes lumped under the blanket-term polymorphic code - program code that modifies itself. There are many approaches. Among the most common techniques are genetic algorithms that try tiny modifications to a known, working algorithm; and gradually, the program evolves into an entirely new algorithm. The hard problem is not creating new executable programs - even a simple pseudorandom number-generator can easily spit out a random series of instructions! The difficult challenge is determining whether the new algorithm has accomplished a useful task. That problem is related to the halting problem; and it is also related to the discipline of optimization and classification. Some-how, the master control program needs to determine whether a newly-created algorithm falls into the category of "working" or "not working," which is a stickier problem than it seems at first glance.

"Explaining" an algorithm - in a way that a human can easily understand - is a challenge of natural language processing and semantic processing. This is a very new field - it is on the edge of very new research problems - so there are not really any currently-available tools that work out-of-the-box. Nimur (talk) 16:50, 5 July 2013 (UTC)

Note that "explain functions" is what a large part of machine learning is concerned with, i.e. finding a model that reproduces a given samples as exactly as possible. See e.g. computational learning theory for the more theoretical part of this. --Stephan Schulz (talk) 18:45, 5 July 2013 (UTC)

There are many programs that are designed to generate code, usually at a low level. For instance, a program that generates code to have a nice procedure to insert a record in a database while taking care of many things that are very boring to a programmer, like checking if someone tries to hack the system. The programmer would know exactly what the generated code would look like, it just saves a lot of typing and tiny but hard to find errors. Much cooler is it when the programmer doesn't know how a particular problem is solved. A compiler might be smart enough to think "You wrote 'if a=0 then a=1', but that will never happen so I'll just ignore that you wrote that". A much better example where the computer outsmarts the programmer is when you ask a database "give me all people living in Colorado, ordered by telephone number, who are actors listed on IMDB". Most modern databases don't start by first looking for all people in Colorado, then order all of those by telephone number, then removing every person that is not listed on IMDB. They make a "plan" and would for instance decide that, since there are not that many actors on IMDB, they should sort the names in IMDB, look up those names in the phone book of Colorado (which is much faster than matching all people in Colorado one by one. Such a phone book is called an Index), and after that sort just a short list by telephone number. While many people have thought about the ways such a plan should be made, the actual plan is completely dependent on the availability of an index, the number of people on IMDB, etc. There are even functions in databases where you can ask "how did you get these results" and "what other indexes would you like next time". I think that's where you can say the algorithm was really invented by the program instead of a human. (I think indexes will not even be created by people in the future, and databases won't "start searching" but will be "pushing" new facts they think might be interesting instead of having to be asked, but I'll keep the dreaming of a perfect database to myself :)) I don't think a computer would come up with a new sorting algorithm like Quicksort very soon if ever. I do think that the wisdom that a neural network develops while learning from looking at millions of tax forms or flight data recorders will at some point be completely automatically distilled into much simpler algorithms that are right 99% of the time, which is quite similar to how humans develop simple algorithms. Joepnl (talk) 00:51, 6 July 2013 (UTC)

The purpose of Bitcoin mining?

Can someone explain to me the purpose of Bitcoin mining? It's my understanding it's just hashing busywork. Are the hashes that mining generates have any purpose? --Navstar (talk) 19:26, 5 July 2013 (UTC)

Are you asking why individual people use their computers to do mining, or why the bitcoin system involves a mining component? They are quite different questions. Looie496 (talk) 20:52, 5 July 2013 (UTC)

The hashing is just busywork. See Proof-of-work system. People mine bitcoin for the same reason people mine gold, hence the name "mining". (Gold does have some uses, unlike bitcoin, but mainly it's valued because of its scarcity.) -- BenRG 00:58, 6 July 2013 (UTC)

Until someone discovers how to generate tones (or arrays and arrays) of BitCoins with a couple of mouse-clicks and forget about scarcity. OsmanRF34 (talk) 10:47, 7 July 2013 (UTC)

MMO game Creating

....I Want To create an MMo Game i need to know just a few things....

1)Do i Need to be A perfect programmer to do this. or I simply can use many programs to make a Massive Game at last.

2)if i will use many different programs to create the game and then integrate/combine the results together. Example :

• using a program to create a map.
• using another program to design characters.

Then integrate the results to get eventually a Good Game. That will work or there is nothing like that at all???

3) If that works it will be able to be added to the other programs to make it MMO.

thanks Note:what i'am talking about may make no sense at all and that maybe because i don't see the whole thing clear so if that true....perhaps...you can give me some more explanation that will be really appreciated. thanks again

A MMORPG is a giant undertaking, and it's usually the work of dozens of people. 3D models for things like buildings and characters are often done in programs like Autodesk Maya, but mostly everything else has to be created by the development team. Maps are usually in a format that's peculiar to that game, so the team ends up developing its own map and scenario editing software. Sometimes you might use an off-the-shelf engine (from Unreal to Unity) or develop your own (a professional 3d engine is literally years of work). There's lots of work for programmers to do (network, game, graphics, tools, etc.), and not much of this can be bought off the shelf. MMORPGs are probably the biggest undertakings in game development, one that gets studios with lots of money and talented people into terrible trouble. I'd advise anyone starting out in game development to begin with small projects like flash games or iOS/Android game apps - even doing a decent job on a single player Android puzzle platform could take a talented person a year of work. -- Finlay McWalterჷTalk 23:15, 5 July 2013 (UTC)

What offers a gentle introduction to the programming side is an LPMud. Being text-based, it does not need all the artwork and deep multimedia frameworks. Also, it's more fun ;-). --Stephan Schulz (talk) 23:43, 5 July 2013 (UTC)

Yeah, you wouldn't have to be an expert programmer per se (you could just be the director of the project) and in that case you would need to hire some people who are. Either way you'll need a big team in order to create an MMO, so I third Finlay's suggestion that you start out small and work your way up. As a side-note, another good 3d model program I've worked with is 3ds Max, though I would reccomend Maya if you're starting out because (IMO) it is a little easier to get into. There are great tutorials available online for these sorts of tools. Good luck! --Yellow1996 (talk) 01:13, 6 July 2013 (UTC)

July 6

Separate clients for singleplayer and multiplayer

I've noticed that several games have done this practice, most especially first-person shooters. They would market the title as a single game, but it has separate executables for the SP and MP portions of it, while others, such as Max Payne 3, would just incorporate both in a single .exe, or just separate portions of it in two dynamic-link library files. Are there any real benefits to this, besides development, as separate teams could just do both portions at the same time?

Having multiple teams wouldn't be a good reason to have multiple executables, as both modes share so much code. And even single player modes are often built in a client-server way; single player has a local server where the game logic, physics, AI, etc. work (this division is evident in games like Quake and Half Life 2, where messages about, and variables to configure, the server are evident throughout the single player console). Not having the game/server logic in the multi-player binary makes for a smaller binary, but a modern OS demand-pages binaries anyway, so really that shouldn't be an issue. Perhaps single player Max Payne /isn't/ coded with a clear client-server divide, meaning the multiplayer version would either have lots of "if multiplayer foo else bar" checks or compile those out (which would mean a distinct binary); I don't know why they'd do things that way (the local server for single player seems like a simple, clever architecture to me) but maybe they do. Or it may all be an artefact of whatever anti-cheating technology they're using (PunkBuster or whatever), as such things check in the client binary for illicit patches (Blizzard's Warden does that kind of thing), and giving it the smallest simplest binary to check, with simply no exploitable game logic present at all, might make that a more tractable process. -- Finlay McWalterჷTalk 11:25, 6 July 2013 (UTC)

Permission to open Outlook file.

My computer recently broke so I bought a new one and downloaded the latest version of Outlook on it, and successfully added all my email accounts. So far so good.

But I have a copy of the .pst file from my old computer and for obvious reasons I want to be able to view it. But when I attempt to open it, it says "File access is denied. You do not have the permission required to open the file..." etc.

So can anyone tell me:

1. WTF? Who should need permission to access a file on their own computer?
2. More importantly, how to work around this?

Best, AndyJones (talk) 13:16, 6 July 2013 (UTC)

You may need to "take ownership" of the file in question. Instructions: XP, Win7. -- Finlay McWalterჷTalk 13:20, 6 July 2013 (UTC)

Excellent, that worked. Many thanks for your help. AndyJones (talk) 16:53, 6 July 2013 (UTC)

Wikipedia Dumps to import them to SQL

Dear Sir/ Madam

From website http://en.wikipedia.org/wiki/Wikipedia:Database_download, I have downloaded dumps from http://dumps.wikimedia.org/. How do I import these huge files to My SQL table format. I tried whats written in the website but it didn't work out.

Is there any easier and alternate solution. Its very urgent as I need to mine some data from the huge files for my journal paper.

Waiting for your reply.

Regards

Most of the dumps are XML, not MySQL-dump format, and need to be imported by a functional MediaWiki install, not MySQL's own tools. The process is described here -- Finlay McWalterჷTalk 20:05, 6 July 2013 (UTC)

USB 2 card (int. hub), power output

If I replace a 2 slot USB 2 module with a 4 slot USB 2, do I get at least the same power on each slot like I had on my old card or will it be divided, like initial power divided by four? Was it divided by two with the 2 slot card? It actually comes down to the basic question on how much power I can get from a USB slot so I don't have to use something like a powered external USB multiple port devise? Think simple and you'll understand my question as I might not used the proper technical terms ;)
Thanks in advance for any help, TMCk (talk) 23:55, 6 July 2013 (UTC)

I assume you mean you're replacing a PCI usb card with a bigger one. Looking at Universal Serial Bus#Power, a USB2 device can draw 500mA from 5V, which is 2.5W. If we look at Conventional PCI, we see that a PCI card can pull 25W off the backplane. Obviously some of that is used to run the card itself (the UHCI/EHCI), but its unlikely that it's remotely close to using all of that 25W (only graphics adapters use serious amounts of power). So (as best as I can say without reading the datasheet for your proposed PCI adapter) it should have plenty of power to run all its ports (indeed, it would be defective if it had more ports than it could supply max power to). 87.112.233.132 (talk) 00:32, 7 July 2013 (UTC)

Thanks for your input. My old USB (PCI) card is about 10 years old (yes, 10 years) and working fine but the other day I connected my GPS for power only and although it worked, my system told me there is not enough power to run the devise. Maybe it meant the devise + other devises connected to it, like an ext. hard drive on one slot and an ext. USB hub (with external power unplugged) with a printer connected. The latter is where I connected my GPS. I would love to install the 4 slot internal (PCI?) USB hub, run the (new) external drive + an older one and a printer one 3 of them while having 1 slot left for other temporary devises. Maybe I should mention that I have a couple of USB 1 slots in use on my PC too. Don't know if they could cut down the amps available at other hubs but if so, I can retire those. Can they [cut down the amps available]? What solutions are there for my system and which one would most likely work the best? And of course, which one would work with what I have? Any idea or do I need to post more information? Please stay on it, thanks, TMCk (talk) 01:58, 7 July 2013 (UTC)

• Also, I have no datasheet for my new 4 slot USB(PCI) card as it came "plain". All I can say is that is has 4 slots externally and one internally. If there is some info printed on the circuit board that might be of help please let me know and I'll provide anything printed on it.TMCk (talk) 02:10, 7 July 2013 (UTC)

Add on: And if I need more power, do I have another option besides an external hub? And if not, is there something I should look out for when buying a new ext. hub? The one I have is not recognized by my system unless I unplug the power cord while starting up my system or coming out of hybernation.TMCk (talk) 00:06, 7 July 2013 (UTC)

July 7

Purpose of transformer component in USB charger/adapter

I have this USB charger/adapter. To use it, you connect either the wall or car transformer to the desired output plug through an extendable cable. The wall transformer's output is given as "5V(DC symbol)400mA±5%", and the car transformer's output is "DC 5V±5% max: 500mA". My question is about the cable, which itself is attached to a small transformer. It's labelled "input: DC5.0V 500mA, output: DC5.5V 350mA MAX". What is the purpose this transformer? --118.174.206.134 (talk) 05:17, 7 July 2013 (UTC)

I guess some devices need a 5.5V input, for example some Panasonic phones take 5.5V. So you need a small transformer to step up from the 5V from USB to the 5.5.--Salix (talk): 16:16, 7 July 2013 (UTC)

Dhaka Lahan, East Champaran, Biahr

Dhaka Lahan is small and peaceful village of Dhaka constituency. It is situated one km west from Gandhi Chowk Dhaka,There are Two wards in this village ward no 19 and 20,the total Population of this village is around 4600 of civilian,if voter concerns in ward no 20 is 1334 and ward no 19 is 900 by 2013.

This is the computing reference desk - do you need help finding information related to a computer topic? If you need help editing Wikipedia, start with WP:HELP or Wikipedia:Tutorial/Editing. You might also consider asking for help at the talk pages of Bihar constituencies, or East Champaran district. Nimur (talk) 08:09, 7 July 2013 (UTC)

iPhone needs Apple car charger?

OK, I have a generic car cigarette lighter to USB adapter I got probably out of the bin next to the cashier at Walgreen Drugs (i.e., it's really generic), which works on my old LG dumbphone and on my new Samsung smartphone, but won't work when my friend's iPhone 5 is plugged in to it; it's not the iPhone cable, since that works with the wall charger. Is there some handshake official Apple car chargers need to do to the cable? The phone doesn't come up with one of those "not the right cable" messages like my old Motorola used to do (even when the cable worked), it just doesn't acknowledge the existence of the car power supply in any way. Gzuckier (talk) 07:13, 7 July 2013 (UTC)

iPhones do recognise (some?) Apple chargers, and charge faster though them. But I've also charged them with generic USB chargers, and regularly charge mine via a computer USB port. In my experience, car USB chargers often supply marginal or below spec voltage (and current), so not all devices accept them. --Stephan Schulz (talk) 08:16, 7 July 2013 (UTC)

Remote administration: different OSs

Can you remote administer a group of users using different OSs (Windowses, Linuxes and Macs) from just one computer (running whatever is more convenient, but preferably Linux)? Or is it only possible when the OSs match (Windows - Windows, and so on)? OsmanRF34 (talk) 10:39, 7 July 2013 (UTC)

Remote administration might be of help. It sounds like it would be a hassle, but I would say it is possible. 64.201.173.145 (talk) 18:22, 7 July 2013 (UTC)

AC transofrmer markings

greetings everyone

When an AC transformer says on its label that its secondary winding is as follows 0.....15 white white i.e. two wires of white coloring are designated as ground (0) and 15volts. but because it is ac I take it doesn't really matter which of these wires is exactly at one point in time is 0v or 15v.. so can I connect them to my pcb where it says 0 volts and 15 volts terminals interchangeably ? right? THAnks!!

Warning: I'm no electrician, so someone please correct me if I'm wrong!! But, I don't see why not. --Yellow1996 (talk) 17:53, 7 July 2013 (UTC)