I'm having troubles with staying signed in on data.stackexchange.com. I have no issues with any other Stack Exchange site -- they all work fine. Once I log in, I don't need to log in every time I visit the site. But with data.se, I need to re-login everytime. As I can't execute queries without captcha without being logged in, this is an issue.  What could be causing this issue? I'm using Google Chrome 31.0.1650.63, if that matters.
I know that we don't have automatic login for the Data Explorer, but what's with the automatic timeout/logout?  There have been times that I am logged into the site, maybe I walk away for a little bit, and I come back to being logged out.    Is there a reason for logging us out of Data Explorer?  If so, is it possible to either remove the timeout or extend the period of time before timeout?
How do the Azkaban escapees get their wands back? Sirius Black and a few Death Eaters escape Azkaban and seem to operate after that with their wands intact.  How come?  If a mere expulsion from Hogwarts entails wand destruction (as happened with Hagrid), shouldn't an Azkaban sentence entail the same?  And even if we imagine that the perceived impossibility of escape from Azkaban made it seem unnecessary to destroy the wand, this would apply to Sirius but not to Death Eaters.  PS: Two comments suggested that the escapees acquired new wands. It would be nice to have a more definitive answer than just a suggestion or a list of possibilities. Thanks.  PPS: Returning the personal property to a released prisoner is one thing, but the wand is a different matter: this is usually the tool of the crime, and I don't see how it can be argued that it should be returned and not destroyed. Again, Hagrid had his wand destroyed and he was not even sentenced to Azkaban.  PPPS: Maybe wand destruction is only done for non-fully-qualified wizards? I have installed Ubuntu on, but now I am trying to install NVIDIA CUDA Toolkit for the GPU. When I install it, it says that there is no driver found, so I have tried to install the driver, but I don't know why after installation, the system not coming up. Maybe it is because of the wrong version of the driver.   When I tried to detect the driver version using sudo lshw -C display , it showed this information:    But here it doesn't say that what is the product name of the driver, and also when I go Software &amp; Updates -> Additional Drivers, then it says NVIDIA Corporation: Unknown.    What should I do? Express $\sqrt{3}\sin\theta - \cos\theta$ as: $a\cos (\theta + \alpha) $ Express $\sqrt{3}\sin\theta - \cos\theta$ as: $a\cos (\theta + \alpha) $  Can someone please explain to me how to go about doing this? I know that hardly any information is passed to the PDF when a .tex file is compiled.  But is there a tool that can convert a PDF document back to (La)TeX? Prove $\sum_{d \leq x} \mu(d)\left\lfloor \frac xd \right\rfloor = 1 $ Are the known exoplanets representative of the population of exoplanets? An  states that most of the 715 newly announced exoplanets orbit very close to their host stars.   Do the theories predict that this is a representative sample and that most planets are very close to their host stars? Or is it just that our current detection techniques are predisposed to finding only those planets close to their stars (because the sensors look for dimming of the host star for example)? Dimensioning of a technical drawing in TikZ Is there is an easy way to mark dimensions in a technical drawing with TikZ?    Is there a library or something?  Edit  I am using XeLaTeX.  Update  I chose Martin's answer because it serves me well for the moment. Ultimately the best solution would be a library that, in an easy and consistent manner, would allow to change the arrow/dimension lines styles, would support polar coordinates, would allow to choose 2 nodes and the vertical distance that you want the dimension to be typeseted etc. PDO SQL-state "00000" but still error? What editors/IDEs are available for easing the process of writing TeX/LaTeX documents? Please state some useful features like code completion, spell checking, building final DVI or PDF files, etc.  This question is undergoing a systematic refurbishment, see  on Meta. If you’d like to see another editor feature covered here or to take care of an editor that’s not covered yet, share your ideas in that meta question.  List of editors Links to answers. Sorting citations using \cites command in biblatex I am using biblatex for citations and bibliography. Now I often have lists of multiple citations, for which biblatex has the \cites command. Now I can get citations to automatically sort if I don't want page numbers, but I cannot get it right with page numbers.  What I want is all citation ordered chronological (oldest first). Is this possible, or must I just do this by hand?  Here is an example.  \documentclass[11pt,oneside]{memoir}  \usepackage[     style=authortitle,     useprefix=false,     maxnames=2,     firstinits=true,     sortcites=true,     uniquename=init,     abbreviate=true,     backend=biber,     sorting=ynt ]{biblatex}  \begin{filecontents}{jobname.bib} @book{tom1,   author = {Author, A.},   year = {2001},   title = {This book is from 2001},   shorttitle = {2001}, } @book{tom2,   author = {Author, A.},   year = {1999},   title = {This book is from 1999},   shorttitle = {1999}, } \end{filecontents}  \addbibresource{jobname.bib}   \begin{document} This one is corrent.\footnote{\Cites{tom1,tom2}.} This one is corrent.\footnote{\Cite{tom1,tom2}.}   This one is incorrent.\footnote{\Cites{tom1}{tom2}.} This one is incorrent.\footnote{\Cites[1]{tom1}[12]{tom2}.} \end{document} Encode URL in JavaScript? How do you safely encode a URL using JavaScript such that it can be put into a GET string?  var myUrl = "http://example.com/index.html?param=1&amp;anotherParam=2"; var myOtherUrl = "http://example.com/index.html?url=" + myUrl;   I assume that you need to encode the myUrl variable on that second line? Can you prove that if $p$ is a prime greater than $5$, then the sum of the squares of the quadratic nonresidues modulo $p$ is divisible by $p$?  Note that I have just proved that the sum of the quadratic residues modulo $p$ is divisible by $p$ for $p$ greater than $3$. Why KL divergence is non-negative? Why is KL divergence non-negative?  From the perspective of information theory, I have such an intuitive understanding:  Say there are two ensembles $A$ and $B$ which are composed of the same set of elements labeled by $x$. $p(x)$ and $q(x)$ are different probability distributions over ensemble $A$ and $B$ respectively.   From the perspective of information theory, $\log_{2}(P(x))$ is the least amount of bits that required for recording an element $x$ for ensemble $A$. So that the expectation $$\sum_{x \in  ensemble}-p(x)\ln(p(x))$$ can be interpreted as at least how many bits that we need for recording an element in $A$ on average.   Since this formula puts a lower bound on the bits that we need on average, so that for a different ensemble $B$ which brings about a different probability distribution $q(x)$, the bound that it gives for each element $x$ will surely not bit that is given by $p(x)$, which means taking the expectation, $$\sum_{x\in ensemble}-p(x)\ln(q(x))$$ this average length will surely be greater than the former one, which leads to $$\sum_{x\in ensemble }p(x)\frac{\ln(p(x))}{\ln(q(x))} &gt; 0$$  I don't put $\ge$ here since $p(x)$ and $q(x)$ are different.  This is my intuitive understanding, is there a purely mathematical way of proving KL divergence is non-negative? The problem can be stated as:  Given $p(x)$ and $q(x)$ are both positive over real line, and $\int_{-\infty}^{+\infty}p(x)dx = 1$, $\int_{-\infty}^{+\infty}q(x)dx = 1$.  Prove $$\int_{-\infty}^{+\infty}p(x)\ln\frac{p(x)}{q(x)}$$ is non-negative.  How can this be proved? Or can this be proved without extra conditions? paragraph numbering I am using the paragraph section head, i.e.,   \paragraph{This is a cool paragraph}    I would like it to compile with numbering. If I change the secnumdepth (i.e., \setcounter{secnumdepth}{4}) this will work, but produce the "wrong" type of numbering, i.e.,      1.1.1.1 This is a cool paragraph      1.1.1.2 This is another cool paragraph etc.   What I would like is      1 This is a cool paragraph      2 This is another cool paragraph   or, if not,      1.1 This is a cool paragraph      1.2 This is another cool paragraph   where the first 1 indicates the section number and suppresses the subsection and subsubsection numbers. Can this be done? Uninstalling Ubuntu from dual boot / changing bootloader Probability of a 2 pair in poker What is wrong with my method of find the probability of a 2 pair?  For the first card we have 52 choices, one this is picked( call it A) we have 3 choices(different suite than A but this same value) for the second card, ( lets call this card B). Now we have AB, to we have to throw away 2 more cards so we don't have 3 of a kind or a four of a kind. Therefore one our third card we have 48 choices and on our fourth card we have 3 choices again similar to above.  On our last card we only have 44 choices left. So the probablity of getting a 2 pair should be (52*3*48*3*44)/(52 choose 5).  But this isn't correct.     Note: I edited this to "2 pair"; the original version was wrong. I have a bunch of files as follows:  04602635_b0294.DAT20120807164534 04602637_b0297.DAT20120807164713 04602638_b0296.DAT20120807164637 04602639_b0299.DAT20120807164819 04602640_b0298.DAT20120807164748 04602641_b0300.DAT20120807164849 04602650_b0301.DAT20120807164921 04602652_b0302.DAT20120807164956   I need to rename them to exclude the prefix. It needs to look like this..  b0294.DAT20120807164534 b0297.DAT20120807164713 b0296.DAT20120807164637 b0299.DAT20120807164819 b0298.DAT20120807164748 b0300.DAT20120807164849 b0301.DAT20120807164921 b0302.DAT20120807164956   EDIT  I forgot to add that I am using Solaris. I see more and more servers that have no domain defined in the /etc/resolv.conf file.  Only a search entry. In what cases is this setup used ? Are there any cases where it must not be used ?  nameserver xxx.xxx.xxx.xxx nameserver yyy.yyy.yyy.yyy nameserver zzz.zzz.zzz.zzz  search domain1 domain2 domain3 ... I want to know if there is a way to switch to console mode from the boot menu.  I have an NVIDIA 1070 and every time there is an update, the GUI stops working. All I need to do is re-install the drivers; however, to do that I need to be in console mode. EDIT: I should have added more information to this question but I'll comment on all answers. In short: I've tried text instead of quiet splash I do see booting activity in text mode; however, I don't get a login screen and ctrl + Alt + F1 doesn't help because GDM keeps trying to restart. Previously I managed to kill GDM through multiple tries but is not working since the latest update. EDIT: After searching for runlevel, I've found  but I think it required me to have a running system to make changes -- please correct me if I'm wrong. Give us better search-by-score syntax tl;dr: Give the score search operator ability to change between greater than and less than.  I just noticed that searching for score:0 turns up only question with a score equal to 0. Searching for score:1 gives everything with a positive score. (&gt;=1) I can live with these. But here's the big one: score:-1. I would expect it to give all the negatively scored posts - there is a minus sign in there. But it doesn't. It gives all the posts &gt;=-1. Greater than? So, my  is that we get more granular search options for score. For example,  score:1 would show all posts with score == 1 score:1+ would show everything score &gt;= 1 score:0 would show all posts with score == 0 score:-1 would show everything score == -1 score:-1- would show al posts where score &lt;= -1  In short, the operator after the number would show which direction to go with the matching. A minus sign means less than, a plus sign means greater than. No sign means exact.