I'm taking Algorithms this term and I wanted to know where I should post questions about material in the course.  Is it  or ? Or other SE site? (I wasn't able to discern from the FAQ.)
There seems to be more than a few computer science/programming Stack Exchange networks (is that the correct term?). Stack Overflow, being the first, has by far the most users, questions, and answers.  What is the reasoning for creating the others, and are there clear guidelines for which kinds of questions should be posted? I can see a large amount of potential overflow, many cases of people not getting a good answer to their question, because the person who has the answer isn't browsing that particular network at the moment.  I understand that they were probably created for organizational purposes, but wouldn't it almost make more sense to just have them as categories under Stack Overflow, keep them separated but still connected, instead of making people have to create multiple 'account's, one for each network?  I am sure there was a very good reason to break them up, but as someone that is new to SE, it can be somewhat intimidating to decide which one to post in to ensure you get a good answer. For example, if I am a computer science student, my first instinct might to be to post in the computer science network, until I see that it literally has 1% of the users as the Stack Overflow network, which still seems to be for programming/computer science related questions.  So my second instinct would then to be to post it into the Stack&nbsp;Overflow site on the basis that I have a significantly higher chance of my question being seen and getting a good answer. Then I notice that there is also a 'programmers' network, and I don't even begin to know where that fits in. I, and I am assuming most people, will probably just post on Stack&nbsp;Overflow to be safe.  My question is, other than the short little description blurb of each one, is there a clear cut set of guidelines which what each network is intended for, what kinds of questions should go to each one, and is anything being done to encourage people to post in these newer, smaller (more specialized?) networks as opposed to just posting in big daddy Stack Overflow?  Now again, this is for computer science/programming/"why isn't this code doing what I want?" related questions, I am not saying that if I had a question about Linux or WordPress or something I would have the same confusion.
In what order should one apply max HP reduction and damage? A character at 10/26 HP is hit by a Wraith and fails the Constitution saving throw. They take 21 damage and their maximum HP is reduced to 5.  Are they unconscious because the 11 excess damage is less than 26 or dead because it's greater than 5? What is the first reference to an internet of computers in science fiction? "Coming soon" pages & SEO Can I use a Thunderbolt display for a macbook pro with a mini display port? "viruses" or "virii"? Is it possible to start windows with NUM Lock on? A password is always combination of characters &amp; numbers. I am so much used to num pad that every time windows start I end up entering wrong password just because NUM lock isn't ON by default. Since it's network login, it takes a bit long time to reset &amp; prompt for right password. Is there a way to enable NUM Lock on when Windows loads? Loading D3.js data from a simple JSON string Is $\frac{\textrm{d}y}{\textrm{d}x}$ not a ratio? In the book Thomas's Calculus (11th edition) it is mentioned (Section 3.8 pg 225) that the derivative $dy/dx$ is not a ratio. Couldn't it be interpreted as a ratio, because according to the formula $dy = f'(x)dx$ we are able to plug in values for $dx$ and calculate a $dy$ (differential). Then if we rearrange we get $dy/dx$ which could be seen as a ratio.   I wonder if the author says this because $dx$ is an independent variable, and $dy$ is a dependent variable, for $dy/dx$ to be a ratio both variables need to be independent.. maybe? NullReferenceException in Unity Since many users are facing the NullReferenceException: Object reference not set to an instance of an object error in Unity, I thought that it would be a good idea to gather from multiple source some explanation and ways to fix this error.  Symptoms I am getting the error below appearing in my console, what does it mean and how do I fix it?  NullReferenceException: Object reference not set to an instance of an object form in a .tpl.php file This is the code in my template.php file.  function studiga_theme_theme($existing, $type, $theme, $path) {         $items['add_property_form'] = array(         'render element' =&gt; 'form',         'template' =&gt; 'node--14',         'path' =&gt; drupal_get_path('theme', 'studiga_theme') . '/templates/node',     );      return $items; }    function custom_add_property_form($form, &amp;$form_state) {     $form['first_name'] = array(         '#type' =&gt; 'textfield',         '#attributes' =&gt; array('placeholder' =&gt; t('First name')),     );     $form['last_name'] = array(         '#type' =&gt; 'textfield',         '#attributes' =&gt; array('placeholder' =&gt; t('Last name')),     );     $form['address'] = array(         '#type' =&gt; 'textfield',         '#attributes' =&gt; array('placeholder' =&gt; t('Address')),     );     $form['city'] = array(         '#type' =&gt; 'textfield',         '#attributes' =&gt; array('placeholder' =&gt; t('City')),     );     $form['state'] = array(         '#type' =&gt; 'select',         '#options' =&gt; array(             'default' =&gt; 'State',             '...' =&gt; '...',         ),     );     $form['zip'] = array(         '#type' =&gt; 'textfield',         '#attributes' =&gt; array('placeholder' =&gt; t('Zip')),     );     $form['email'] = array(         '#type' =&gt; 'textfield',         '#attributes' =&gt; array('placeholder' =&gt; t('Email')),     );     $form['phone'] = array(         '#type' =&gt; 'textfield',         '#attributes' =&gt; array('placeholder' =&gt; t('Phone')),     );     $form['submit'] = array(         '#type' =&gt; 'submit',         '#value' =&gt; 'Submit',     );      return $form; }   This is the code in node--14.tpl.php.                                          Contact Information                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  &lt;div class="row"&gt;     &lt;div class="small-12 medium-12 large-8 large-offset-2 columns"&gt;         &lt;?php print render($form['submit']); ?&gt;     &lt;/div&gt; &lt;/div&gt;     But no fields are appearing - what am I doing wrong? You can't have a straight forward  in a tpl.php file can you? Simplify $\arctan (\frac{1}{2}\tan (2A)) + \arctan (\cot (A)) + \arctan (\cot ^{3}(A)) $ How to simplify $$\arctan \left(\frac{1}{2}\tan (2A)\right) +  \arctan (\cot (A)) + \arctan (\cot ^{3}(A)) $$ for  $0&lt; A&lt; \pi /4$?  This is one of the problems in a book I'm using. It is actually an objective question , with 4 options given , so i just put $A=\pi /4$ (even though technically its disallowed as $0&lt; A&lt; \pi /4$) and got the answer as $\pi $ which was one of the options , so that must be the answer (and it is weirdly written in options as $4 \arctan (1) $ ).  Still , I'm not able to actually solve this problem. I know the formula for sum of three arctans , but it gets just too messy and looks hard to simplify and it is not obvious that the answer will be constant for all $0&lt; A&lt; \pi /4$. And I don't know of any other way to approach such problems. How do I rotate a tikz rectangle about a specific axis? I am trying to create a beamer animation using tikz, but I can't even get basic rotating of a tikz image working as desired.  I have a rectangle specified by  \draw[rounded corners,dotted] (-3.5,0) rectangle (-0.5,2);   I would like to rotate this rectangle about the point (-1,.5) (which is near the bottom right corner of the rectangle).  I've tried:  {\rotatebox[origin=c,x=-1,y=.5]{130}{             \draw[rounded corners,dotted] (-3.5,0) rectangle (-0.5,2);}}   But this produces an error.  If I just use the origin=c option, it compiles, but it rotates the rectangle about the point (0,0).  I've also tried it with just the x=-1,y=.5 (without the origin option), and it fails to compile.  I have searched the documentation, which is where I learned about the options x=xdim and y=ydim.  However, I can't find a single example demonstrating how these options should be used.  Any suggestions would be greatly appreciated.    Also, if there is a better command for rotating things that will be more suitable for use in a beamer animation, please let me know.  Thanks! How do I change the location of macOS screen captures? As a developer, I take a lot of screen captures. I often take screen shots to share with Stack Exchange members in chat.  The problem is my Desktop is so cluttered with screen captures that they're now overlapping! I'd like to save all screenshots in a dedicated folder or directory.  In macOS, how do I change the default location where screen captures are saved?  These are the screen shots taken with CommandShift3 or CommandShift4 keyboard shortcuts.  I would prefer a solution which doesn't require installing any software. What is the Unix command to create a hardlink to a directory in OS X? How do you create a hardlink (as opposed to a symlink or a Mac OS alias) in OS X that points to a directory? I already know the command "ln target destination" but that only works when the target is a file. I know that Mac OS, unlike other Unix environments, does allow hardlinking to folders (this is used for Time Machine, for example) but I don't know how to do it myself. I was considering playing a Summoner in my next Pathfinder campaign, and I decided that I wanted my Eidolon to be a a four-armed giant (the character being a Gnome with a height complex).  Well, I thought to myself: If it has four arms, then shouldn't it be able to wield two two-handed weapons?  As far as I can tell, it should work. That said, how would that work, exactly? I would assume that it would work like usual two-weapon wielding as far as feats and the like, and it would gain all the bonuses from two-weapon wielding as well. However, as this isn't exactly something that happens often, and thus there are no rules for it (that I can find) I can't be sure of any of this. Does anyone know of anything that could help me with this? Today I was informed by VFS that my tourist visa for UAE got approved. I'm travelling to UAE on 16th December 2014 and returning on 7th Jan 2015. But when I checked the "valid until" date on the visa it states 30 December 2014.    Does this date mean I should return before December 30th? Should I get it corrected from VFS? How does item level and rarity affect the possible attributes? Show $$\frac{(2n)!}{n!\cdot 2^n}$$ is an integer for $n$ greater than or equal to $0$.   Could anyone please help me with this proving? Thanks! About an Hour ago, I faced a problem and tried different ways to solve it.  At last I was going to post my Question on Stack Overflow, but the last trick which came in my mind worked, and the problem got resolved.    Now, if I want to post that problem on Stack Overflow with the solution which worked for me, for the purpose to help other newbies to get their answer if they face the same problem, what is the proper way of posting such solution to a problem? Shell script throws a not found error when run from a sh file. But if entered manually the commands work I'm trying to use the following script to generate a sitemap for my website. When I run it as sh thsitemap.sh I get an error like this and creates an empty sitemap.xml file:  thsitemap.sh: 22: thsitemap.sh: [[: not found thsitemap.sh: 42: thsitemap.sh: [[: not found thsitemap.sh: 50: thsitemap.sh: Syntax error: "(" unexpected   But as the same user root when I manually copy and paste these lines on the terminal, it works without any error and the sitemap.xml file have all the urls. What's the problem? How can I fix this?  #!/bin/bash ############################################## # modified version of original http://media-glass.es/ghost-sitemaps/ # for ghost.centminmod.com # http://ghost.centminmod.com/ghost-sitemap-generator/ ############################################## url="techhamlet.com" webroot='/home/leafh8kfns/techhamlet.com' path="${webroot}/sitemap.xml" user='leafh8kfns'       # web server user group='leafh8kfns'      # web server group  debug='n' # disable debug mode with debug='n' ############################################## date=`date +'%FT%k:%M:%S+00:00'` freq="daily" prio="0.5" reject='.rss, .gif, .png, .jpg, .css, .js, .txt, .ico, .eot, .woff, .ttf, .svg, .txt' ############################################## # create sitemap.xml file if it doesn't exist and give it same permissions # as nginx server user/group if [[ ! -f "$path" ]]; then     touch $path     chown ${user}:${group} $path fi  # check for robots.txt defined Sitemap directive # if doesn't exist add one # https://support.google.com/webmasters/answer/183669 if [ -f "${webroot}/robots.txt" ]; then SITEMAPCHECK=$(grep 'Sitemap:' ${webroot}/robots.txt)     if [ -z "$SITEMAPCHECK" ]; then     echo "Sitemap: http://${url}/sitemap.xml" &gt;&gt; ${webroot}/robots.txt     fi fi ############################################## echo "" &gt; $path  # grab list of site urls list=`wget -r --delete-after $url --reject=${reject} 2&gt;&amp;1 |grep "\-\-"  |grep http | grep -v 'normalize\.css' | awk '{ print $3 }'`  if [[ "$debug" = [yY] ]]; then     echo "------------------------------------------------------"     echo "Following list of urls will be submitted to Google"     echo $list     echo "------------------------------------------------------" fi  # put list into an array array=($list)  echo "------------------------------------------------------" echo ${#array[@]} "pages detected for $url"  echo "------------------------------------------------------"  # formatted properly according to # https://support.google.com/webmasters/answer/35738 echo "&lt;?xml version=\"1.0\" encoding=\"UTF-8\"?&gt; &lt;urlset xsi:schemaLocation=\"http://www.sitemaps.org/schemas/sitemap/0.9  http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd\" xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns=\"http://www.sitemaps.org/schemas/sitemap/0.9\"&gt;" &gt; $path  echo '     ' &gt;&gt; $path;    for ((i=0;i&lt;${#array[*]};i++)); do echo "&lt;url&gt;     &lt;loc&gt;${array[$i]:0}&lt;/loc&gt;     &lt;lastmod&gt;$date&lt;/lastmod&gt;     &lt;changefreq&gt;$freq&lt;/changefreq&gt;     &lt;priority&gt;$prio&lt;/priority&gt; &lt;/url&gt;" &gt;&gt; $path    done echo "" &gt;&gt; $path echo "&lt;/urlset&gt;" &gt;&gt; $path  # notify Google # URL encode urls as per https://support.google.com/webmasters/answer/183669 if [[ "$debug" = [nN] ]]; then     wget  -q --delete-after http://www.google.com/webmasters/tools/ping?sitemap=http%3A%2F%2F${url}%2Fsitemap.xml      rm -rf ${url} else     echo "wget  -q --delete-after http://www.google.com/webmasters/tools/ping?sitemap=http%3A%2F%2F${url}%2Fsitemap.xml"      echo "rm -rf ${url}" fi echo "------------------------------------------------------"  exit 0