Interpolate line not working
Why does no line appear when using Interpolate Line in ArcMap?
dpkg exit with error "cannot scan updates directory `/var/lib/dpkg/updates/': No such file or directory", how to fix it? Earlier, I had a problem with a package, and I (wrongly) ran this:  rm -r /var/lib/dpkg/*   See also .  Now when I try to upgrade, I get this:  E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it? masoud@masoud-PC:~$ sudo apt-get upgrade  E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?   and when I use: sudo dpkg --configure -a   I get this:  dpkg: error: cannot scan updates directory `/var/lib/dpkg/updates/': No such file or directory     and for sudo apt-get upgrade -f get:  Reading package lists... Done Building dependency tree        Reading state information... Done Correcting dependencies... failed. The following packages have unmet dependencies:  ia32-libs : Depends: ia32-libs-multiarch but it is not installable  wine1.4 : Depends: wine1.4-i386 (= 1.4.1-0ubuntu5) but it is not installable E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages. E: Unable to correct dependencies I'm trying to get through Spivak's Calculus on my own and even though I kinda understand induction I'm not so sure that's the case when it comes to complete induction. So I tried to do a starred problem which involves using it. But I'm not sure that my proof is valid, can someone check this for me?  So the problem is that I have to prove that     For every natural $n&gt;1$, if $n$ is not prime we can write it as a product of primes.   I'm starting with a base case. For $n=2$, $n$ is prime, so the assumption holds.  Let's assume that for some $n &gt; 1$ and also all numbers $p &lt;= n$ the assumption holds.  Then $n+1 = cd$. If $n+1$ is not prime, then $c &lt; n+1$ and $d &lt; n+1$, but as they are natural numbers, we can also write that $c &lt;= n$ and $d &lt;= n$. But we assumed that if $p &lt;= n$, and $p$ is not prime, we can write it as a product of primes. So if $c$ or $d$ are not primes, we can write them as a product of primes. That means that $n+1$ can be written as a product of primes if it's not prime, which completes the proof. Placing nodes midway on paths using |- or -| in tikz I make frequent use of |- and -| with computed points in diagrams, like so:  \coordinate (a) at (0,0); \foreach \x in (1,...,10) {     \coordinate (b) at ({whateverFunction(\x)},{whateverOtherFunction(\x)});     \draw (a) |- (b); %Straight line segment     \draw (b) -| (a); %Another straight line segment     \coordinate (a) at (b); }   To get plots like:   I would like to be able to label the midpoint of each line segment, but doing something like node[midway,above] {a} does not act like expected:    I want something like:    Why does midway not work, and what is a good workaround here? How to fake a package version installed? Being an early adopter and using 11.04 daily builds I sometimes meet a situation when some packages require earlier versions of other packages than those I have installed. Usually newer (but refused) versions of needed packages provide all the functionality of their older versions.  If I use dpkg -i --force-depends-version to install dependent packages everything works fine, I've never seen a problem.  Instead of manually downloading and installing every package, can I just make the system pretend there is a specific package version installed when there is a newer? Or is there a --force-depends-version key equivalent for apt-get? A user just posted his question a second time here on meta after the first was closed as a duplicate. I wrote a comment on the second post, explaining that the answer to his question is in the linked duplicate and that he shouldn't circumvent the closure process by asking a second identical question.  When the second post was closed as a duplicate my comment was automatically deleted. As far as I understand this is a heuristic that removes obsolete comments, which it considers every comment that contains a link to one of the duplicates.  This heuristic is too aggressive and removes comments that go beyond "Duplicate here: link". I suggest that it should be changed to only remove the default duplicate comment, and not any comment that was edited by the owner nor any free-form comment that happens to include a link to the duplicate.  This also triggers for any comment that contains the word "duplicate" and link to any question, not only the question being chosen as duplicate, which makes this much worse. I'm talking about at least two juvenile sci-fi novels, read between second and fourth  public grades (U.S.A.) which for me places them around 1956-9.  The protagonists are a brother and sister, presumably my (then) age. They are friends  with a single man, a scientist who has built a rocket ship. The scientist is little fey,  physically; a (relatively) large, round head, balding, short in stature and striking long,  thin hands and fingers.  The rocket ship's final preparation is to slop a viscous, clear gloop over EVERYTHING, inside and out from a pail with a paintbrush. In flight, there is an encounter with the moon, and a very small planet with (non-threatening) inhabitants not physically unlike the fey rocket scientist. The planet orbits either the moon or the earth, not the sun, and strangely, some kind of mushroom(!) theme runs through the books. Really.  That's it. That's all I got (I was nine at the most, fer chrissake). My recollection tells me there was concealment from parents, a particular name for the planet and people  and flight through a spatial fog. I mention these things separately because I am less sure  of them than the previous two paragraphs. The author was blissfully unrepentant of the laws  of physics:  Earth gravity on a micro-planet, fog in space and super-gloop to ready the  ricketiest rocket. Worked for me.  I'm guessing even Richard, my previous mentor/savior might not be familiar with these.  Anybody? Author, titles? Or do you just recognize one of these? Why do light sources appear as stars sometimes? See for example this photo:    From my experience, the longer the exposure the stronger can this effect be observed. Is this correct? Are there any other factors that influence the creation of these stars (is there a better word for it, by the way?) And what exactly does technically happen? Where do I place my own .sty or .cls files, to make them available to all my .tex files? Python Implementation of Track-to/aim constraint Why do positive and negative variants of the same question elicit the same answer? How to rename wp-includes folder? Is there a way that we could rename wp-includes folder   I have found out there are ways to do for other folders. But how do we do it for wp-includes folder? Types in MySQL: BigInt(20) vs Int(20) Kernel requires an x86-64 CPU, but only detected an i686 CPU. How can I install Lubuntu/Ubuntu? I'm trying to install Lubuntu on my laptop (sorta old 2005). [Laptop stats: Intel® Celeron® CPU 410 @ 1.46 GHz 1.47GHz, 448 MB of RAM]  I press Install and this message appears:   This kernel requires an x86-64 CPU, but only detected an i686 CPU.  Unable to boot - please use a kernel appropriate for your CPU.   What can I do to install Lubuntu on my computer? about://(null) popup? I encountered a popup similar to this one this morning while checking the weather report at  in Safari, though I have not been able to reproduce it.  The title is "about://(null)" and the text "Why you no play Candy Crush!!"  The popup occurred twice.  I tapped Cancel both times.  I suspect the source of this is rogue JavaScript in an ad network, judging from the fact that the screenshot below shows it in an ad-supported application, and when I saw it, I was on an ad-supported website.  My phone is not jailbroken.  I'm wondering if anyone is able to identify the source of the popup definitively.  Speculation is running rampant on Apple's support communities and elsewhere, from push notifications (delete Facebook and all your games!) to carrier notifications (which don't work on iPod Touches…), and my gut tells me little of it is helpful.  But I could also be very wrong.  (This is not my screenshot; it comes from .)    UPDATE 1: The Candy Crush people have this to say, but I'm not (yet) convinced there's actually something installed that is to blame:   UPDATE 2: Just reproduced it in the iOS Simulator while clicking around woodtv.com, but I'm not sure how to track it down further from here. When light waves enter a medium of higher refractive index than the previous, why is it that:  Its wavelength decreases? The frequency of it has to stay the same? Working with IPv6 Addresses in PHP After searching around somewhat thoroughly, I noticed a slight lack of functions in PHP for handling . For my own personal satisfaction I created a few functions to help the transition.  The IPv6ToLong() function is a temporary solution to that brought up here: . It will split the IP in to two integers and return them in an array.  /**  * Convert an IPv4 address to IPv6  *  * @param string IP Address in dot notation (192.168.1.100)  * @return string IPv6 formatted address or false if invalid input  */ function IPv4To6($Ip) {     static $Mask = '::ffff:'; // This tells IPv6 it has an IPv4 address     $IPv6 = (strpos($Ip, '::') === 0);     $IPv4 = (strpos($Ip, '.') &gt; 0);      if (!$IPv4 &amp;&amp; !$IPv6) return false;     if ($IPv6 &amp;&amp; $IPv4) $Ip = substr($Ip, strrpos($Ip, ':')+1); // Strip IPv4 Compatibility notation     elseif (!$IPv4) return $Ip; // Seems to be IPv6 already?     $Ip = array_pad(explode('.', $Ip), 4, 0);     if (count($Ip) &gt; 4) return false;     for ($i = 0; $i &lt; 4; $i++) if ($Ip[$i] &gt; 255) return false;      $Part7 = base_convert(($Ip[0] * 256) + $Ip[1], 10, 16);     $Part8 = base_convert(($Ip[2] * 256) + $Ip[3], 10, 16);     return $Mask.$Part7.':'.$Part8; }  /**  * Replace '::' with appropriate number of ':0'  */ function ExpandIPv6Notation($Ip) {     if (strpos($Ip, '::') !== false)         $Ip = str_replace('::', str_repeat(':0', 8 - substr_count($Ip, ':')).':', $Ip);     if (strpos($Ip, ':') === 0) $Ip = '0'.$Ip;     return $Ip; }  /**  * Convert IPv6 address to an integer  *  * Optionally split in to two parts.  *  * @see https://stackoverflow.com/questions/420680/  */ function IPv6ToLong($Ip, $DatabaseParts= 2) {     $Ip = ExpandIPv6Notation($Ip);     $Parts = explode(':', $Ip);     $Ip = array('', '');     for ($i = 0; $i &lt; 4; $i++) $Ip[0] .= str_pad(base_convert($Parts[$i], 16, 2), 16, 0, STR_PAD_LEFT);     for ($i = 4; $i &lt; 8; $i++) $Ip[1] .= str_pad(base_convert($Parts[$i], 16, 2), 16, 0, STR_PAD_LEFT);      if ($DatabaseParts == 2)             return array(base_convert($Ip[0], 2, 10), base_convert($Ip[1], 2, 10));     else    return base_convert($Ip[0], 2, 10) + base_convert($Ip[1], 2, 10); }   For these functions I typically implement them by calling this function first:  /**  * Attempt to find the client's IP Address  *  * @param bool Should the IP be converted using ip2long?  * @return string|long The IP Address  */ function GetRealRemoteIp($ForDatabase= false, $DatabaseParts= 2) {     $Ip = '0.0.0.0';     if (isset($_SERVER['HTTP_CLIENT_IP']) &amp;&amp; $_SERVER['HTTP_CLIENT_IP'] != '')         $Ip = $_SERVER['HTTP_CLIENT_IP'];     elseif (isset($_SERVER['HTTP_X_FORWARDED_FOR']) &amp;&amp; $_SERVER['HTTP_X_FORWARDED_FOR'] != '')         $Ip = $_SERVER['HTTP_X_FORWARDED_FOR'];     elseif (isset($_SERVER['REMOTE_ADDR']) &amp;&amp; $_SERVER['REMOTE_ADDR'] != '')         $Ip = $_SERVER['REMOTE_ADDR'];     if (($CommaPos = strpos($Ip, ',')) &gt; 0)         $Ip = substr($Ip, 0, ($CommaPos - 1));      $Ip = IPv4To6($Ip);     return ($ForDatabase ? IPv6ToLong($Ip, $DatabaseParts) : $Ip); }   Someone please tell me if I'm reinventing the wheel here or I've done something wrong.  This implementation converts IPv4 to IPv6. Any IPv6 address it doesn't touch. I have a column in an Excel spreadsheet with several hundred entries, and some of these entries are duplicated.  I would like to remove all duplicate entries from the column so that each entry remaining is unique.   Is there a way to accomplish this automatically? Prove that $\gcd(a^n - 1, a^m - 1) = a^{\gcd(n, m)} - 1$ For all $a, m, n \in \mathbb{Z}^+$,   $$\gcd(a^n - 1, a^m - 1) = a^{\gcd(n, m)} - 1$$ Isomorphism $H_n(D^n, S^{n - 1};A)$ and $A$ The homomorphism $a \mapsto [[a \cdot f]]$ is supposed to be an isomorphism between $A$ and $H_n(D^n, S^{n - 1};A)$ for any homeomorphism $f: \Delta^n \to D^n$. I have proven that it is well defined and injective, but why is it surjective?  The group $H_n(D^n, S^{n - 1};A)$ is generated by elements of the form $a \cdot \sigma + b \cdot \tau + c \cdot \partial(\kappa)$ where $\sigma: \Delta^n \to D^n$, $\tau: \Delta^n \to S^{n - 1}$ and $\kappa: \Delta^{n + 1} \to D^{n + 1}$ and I do not see how an element of this form represents the same equivalence class of $[[m \cdot f]]$ for some $m \in A$. We can write $\sigma$ as $f f^{-1} \sigma$ to get $f$ in there, but I don't see that working out. Any hints? Why does the base-emitter voltage of a BJT decrease with temperature? According to Sedra/Smith Microelectronic Circuits, \$v_{BE}\$ changes by \$-2\text{mV}/\text{°C}\$. I cannot understand how this could possibly be the case given the equations I am familiar with.  With all currents kept constant, we have:  \$\large{i_E = \frac{I_s}{\alpha}e^{v_{BE}/V_T}}\$  To keep \$i_E\$ constant, any change in \$V_T\$ would have to be accompanied by a change of the same factor in \$v_{BE}\$, otherwise \$\alpha\$ or \$I_s\$ would have to change, which as far as I understand is not possible.  So, how can \$v_{BE}\$ be inversely proportional to \$V_T\$?