Wikipedia:Reference desk/Archives/Computing/2014 August 28

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August 28

Cellular Automaton

Does this concept exists and/or is discussed somewhere?

It's a grid cellular automaton, similar to Conway's game of life; initially the board is randomly populated with cells having either of two colours. At each iteration, each cell changes into the same colour as the majority of its neighbours, or remains unchanged in case of a tie. At the end the board becomes polarised with each color having one section of the board.

Has someone already thought of such a thing?

Duomillia (talk) 01:42, 28 August 2014 (UTC)

I read something related that in a Stephen Hawking book somewhere (either A Brief History of Time or its sequel) related to entropy and black holes, but other than that I cannot say. KonveyorBelt 01:47, 28 August 2014 (UTC)

For further information, I had thought of this when I read this article in the NYT: [1]. I had written a (simple) computer program many many years ago when I was a child that simulated that type of game, and I was curious whether I was the first. It seems like such a simple idea I figure it's possible someone else has also thought of it. Duomillia (talk) 02:01, 28 August 2014 (UTC)

I've certainly read of it, and also of the inverse, where a cell seeks to be opposite to a majority of its neighbors; but can't now recall where. Something by Douglas Hofstadter perhaps? —Tamfang (talk) 02:35, 28 August 2014 (UTC)

Seems related to the Ising model. --88.152.132.111 (talk) 05:58, 28 August 2014 (UTC)

That would be a Life-like cellular automata notated as B5678/S45678 (i.e. a cell is "born" if there are 5 or more adjacent alive cells, and dies if there are 3 or less adjacent alive cells). There is a java applet somewhere online which lets you input a general life-like ruleset, but I can't seem to find it at the moment. MChesterMC (talk) 08:59, 28 August 2014 (UTC)

Damn, now I also wish I could find such an applet or other program, as this has started to genuinely interest me. I figure that the opposite automaton User:Tamfang mentioned would cause an ever-changing grid that appears chaotic, but I don't know for sure. I do have the necessary programming skills for the game logic, but I'm unfamiliar with the graphics output methods of modern operating systems. If all else fails, I might resort to loading up FS-UAE and programming a simple test program with AMOS Professional, which I was fortunate enough to buy way back in the middle 1990s when Amigas were still in mainstream use and I still had a working one. JIP | Talk 18:18, 28 August 2014 (UTC)

Golly is available on most platforms, and can run Conway's Life with arbitrary life/death parameters. CS Miller (talk) 20:14, 28 August 2014 (UTC)

By golly, it works. (Pun intended.) I tried the B5678/S45678 rule specified above, and it makes thin lines of cells die out instantly. Thick blobs, on the other hand, pretty much instantly stabilise to a formation that never changes. Specifying an inverse rule was more of a challenge. I tried B0123/S01234, and it's mostly the same, but instead of stabilising to a formation that never changes, thick blobs stabilise to a formation that is constantly wiggling its edges in a two-generation cycle. JIP | Talk 17:38, 29 August 2014 (UTC)

Celular automata are often used in game programming to construct 'cave-like' environments with a minimum of processor overhead. The Procedural Content Generation wiki has a few examples of the process, though they're beyond my own programming ability at the moment. 207.6.127.98 (talk) 23:23, 28 August 2014 (UTC)

Wireless Connectivity

Hey guys, I'm on a Lenovo G500s Touch (bought new fall 2013) and I have had some sporadic connectivity issues in the past, but here lately I have been having consistent wireless connectivity issues. After endless pawing through Google searches, forums, how-to videos, etc., there doesn't appear to be a definitive answer to what my problem is.

I have an Intel i5, 6GB RAM, Intel Graphics 4000, and my wireless adapter listed is an Intel Centrino N-135. I am currently running Windows 8.1.

My problem is that very regularly I will either get incredibly sluggish internet speeds (regardless of where I am), or a blatant disconnection. Then, after running the default "Troubleshoot" it usually says one of the following:

A) Default gateway not available (sometimes it solves it, sometimes it remains unfixed) B) Resetting wireless adapter (sometimes this fixes it, sometimes it makes it worse) C) The DNS service is not responding (or something along these lines)

Regardless of what problem arises, others within 1 meter of myself are experiencing no wireless issues on the same connection, and the problem persists in several locations I regularly connect to the internet.

Something interesting to note is that when I initially attempt to connect to any sort of wireless signal, it always takes extremely long and displays the "Connecting is taking longer than usual" message, then even once it connects it always say "Connection Limited" even though I may have internet access, and troubleshooting results in one of the 3 things above.

I have tried deleting the Lenovo wireless drivers and installing Windows drivers instead, and while this somewhat alleviated the problem, it definitely did not go away. I have read that some Lenovos come with mis-connected wireless cables, as well, though I have yet to actually open my computer to try this. I have also read that it may be the wireless card released with the G500 series, though as I said, there doesn't appear to be a consensus on what the actual problem/solution is.

My work requires constant internet connectivity, and having spans of disrupted services is becoming more than just an inconvenience. Is it worth trying to fix, or should I just sell the laptop and get a different one (I have someone who would buy it, and I also have a different computer I could buy as well).

I have had no issues with the computer other than this.

Cheers — Preceding unsigned comment added by 116.100.152.237 (talk) 06:49, 28 August 2014 (UTC)

Hmmm - it's looking like a hardware issue that can probably only be solved by having someone pull the machine apart and examine it. Software issues rarely result in these kinds of symptoms - so I doubt that's what's going wrong. It could have been just poor design of the machine - but design errors seldom get worse with age. So it's looking like you have a hardware problem of some kind. If I had to guess, I'd say the antenna connection was bad...but that's just a wild guess). With luck your machine may still *just* be in warranty (looks like they offer 1 year in most places in the world)...so don't delay - you may have very little time to get this resolved. SteveBaker (talk) 17:11, 28 August 2014 (UTC)

Can you run an ethernet cable from your home router to your desk? There are also USB WiFi receivers available, which will work, assuming that there is a USB port towards the back of your laptop.

Restricting Google searches to return only perfect matches

Is there a way to restrict Google search for a text string so that only perfect matches are returned? Not a single bit of difference allowed, every single character in exactly the sequence as entered, not one comma or capital out of place. Google's "fuzzy logic guestimation" is very irritating when I'm trying to find only one specific document. The one I want gets buried in a pile of a zillion almost kinda sorta more-or-less approximately maybe perhaps roughly similar crud! Roger (Dodger67) (talk) 16:09, 28 August 2014 (UTC)

Placing the search term in "quote marks" will do the trick, or you can use the advanced search option. AFAIK the quote marks works on other search engines as well. WegianWarrior (talk) 16:17, 28 August 2014 (UTC)

I'm almost certain that the answer is "No". WegianWarrior is incorrect. The quote marks trick doesn't search for literally what you type. I'm pretty sure that Google doesn't index punctuation and spacing. So, for example if I search for "to be or not to be" (in quotes), I get the Wikipedia "To be or not to be" page as the top hit in the search results - despite the fact that the first 'T' is capitalized. And "Eats shoots, and...leaves!" returns the first link as "Eats shoots & leaves" (with the ampersand and without my stupid punctuation). If I search for "Eats, shoots and leaves" - then that exact string is still only the fourth hit after three "Eats shoots & leaves" hits (no comma, with ampersand).

The problem is almost certainly one that cannot be solved. Google doesn't store the literal text of the web pages it searches. Searching through all of those web sites in a tiny fraction of a second is impossible. Rather, it indexes just the individual words, converted to monocase, stripped of punctuation, spacing or tiny words like "a". The double quotes trick really only guarantees that those words will be found in that order and without other words in between...it's nowhere near an exact binary match.

SteveBaker (talk) 17:01, 28 August 2014 (UTC)

There's one more trick, which is to suppress hits based on words used on pages linking to the given page. To do that, use the advanced search form and select that the hits must occur "in the text of the page"; or in the regular search blank, put allintext: as the first search term. For example,

                 "cable car"

returns, among other things, the page http://www.emiratesairline.co.uk/, which is about a cable-car line (or more precisely, a gondola line) but does not use the phrase. If you change it to

                 allintext: "cable car"

then you will not get that hit. But either version of the search finds http://www.tfl.gov.uk/modes/emirates-air-line/, which does use the phrase. --70.49.168.18 (talk) 21:06, 28 August 2014 (UTC)