Remove tikz blank space at end of arrow edges

There's a mysterious blank space at the edges of the arrows between node 3 and node 9 below, whereas all the other edges are fine. How can I fix?    \documentclass[border=3mm]{standalone} \usepackage{tikz} \usetikzlibrary{matrix, calc, graphs, fit, backgrounds, positioning} \definecolor{myorange}{rgb}{1,0.8,0} \definecolor{mygreen}{rgb}{0.8,1.0,0.533} \begin{document} \begin{tikzpicture}[>=latex,thick,black!50,text=black, every new ->/.style={shorten >=0pt}, seqpoint/.style={   rectangle,minimum size=4mm,rounded corners=2mm,   inner sep=0,   thick,draw=black!50,   fill=myorange,   font=\footnotesize\sffamily }, func/.style={   rectangle,minimum width=16mm,rounded corners=1mm,   thick,draw=black!50,   fill=mygreen,   font=\ttfamily }, parentfunc/.style={   rectangle,minimum width=16mm,rounded corners=1mm,   thick,draw=black!50,   font=\ttfamily,   append after command={node[below right = 3pt of \tikzlastnode.north west, font=\ttfamily] {#1}} }, graphs/every graph/.style={edges=rounded corners}] \matrix[column sep=4mm, row sep=4mm] {  & \node (s1) [seqpoint] {1}; & \\ \node (s2) [seqpoint] {2}; & \node (s4) [seqpoint] {4}; & \node (s6) [seqpoint] {6};\\ \node (foo) [func] {foo}; & \node (bar1) [func] {bar}; & \node (bar2) [func] {bar};\\ \node (s3) [seqpoint] {3}; & \node (s5) [seqpoint] {5}; & \node (s7) [seqpoint] {7};\\ & & \node (baz) [func] {baz};\\ & & \node (s8) [seqpoint] {8};\\ & \node (s9) [seqpoint] {9}; &\\ & \node (quuxspace) []{}; & \\ & \node (s10) [seqpoint] {10}; &\\ & \node (tweedledee) [func] {tweedledee}; &\\ & \node (s11) [seqpoint] {11}; &\\ & \node (tweedledum) [func] {tweedledum}; &\\ & \node (s12) [seqpoint] {12}; &\\ & \node (s13) [seqpoint] {13}; &\\ }; \begin{scope}[on background layer] \node (quux) [parentfunc=quux, fill=mygreen!20, fit=(quuxspace) (s13) (tweedledee) (tweedledum)] {}; \node (isr) [parentfunc=isr, fit=(s1) (quux) (foo) (bar2)]{}; \end{scope} \graph [use existing nodes] { s1 -> s2 -> foo -> s3 -> s9;   s1 -> s4 -> bar1 -> s5 -> s9; s1 -> s6 -> bar2 -> s7 -> baz -> s8 -> s9 ; s9 -> s10 -> tweedledee -> s11 -> tweedledum -> s12 -> s13; }; \end{tikzpicture} \end{document}


iPad won't turn on after a complete battery drain

My iPad mini retina is out of warranty,  I forgot to plug in my iPad after the critical battery warning and it went some minutes following the warning. I was not worried because same thing had happened a few times before and iPad was perfectly okay after charging it. However, this time I remember seeing a flash of blue screen immediately after it went black. Then, I plugged it in an waited for a while and tried starting it. Ever since, it fails to start hanging on the apple logo with white background screen.   I tried to connect to my Mac but nothing showed up in iTunes. I am worried now. Can I troubleshoot this or is it broken and needing repair?


Trouble with template constructor of non-template class

While searching for an answer to another  I developed a a helper class that would work with any kind of container of integers. Specifically, my class would lookup container values based on some criteria. In order to work with different types of containers, my class obviously needs to operate not on containers themselves but on their iterators. I don't need to reference containers anywhere in my class, I use only iterators and only in class constructor.  // Header file.   class MyLookup {     public:      template<typename ForwardIt>   // Forward iterator though sequence of integers     MyLookup(ForwardIt begin, ForwardIt end)     ...  }   // Implementation file   template<typename ForwardIt>  MyLookup::MyLookup(ForwardIt begin, ForwardIt end) {  ...  }   // Use file  std::vector<int> foo; ... MyLookup lookup(foo.begin(), foo.end());   While using CLang the initial compiler pass succeeds but then I get linker errors:  Undefined symbols for architecture x86_64:   "MyLookup::MyLookup >(std::__1::__wrap_iter, std::__1::__wrap_iter)", referenced from: ...  Any idea what am I doing wrong?


How do I implement URL rewriting in my .htaccess file?

I'd like to do some URL rewriting (Why? See .) so that instead of users seeing addresses like   labouseur.com/course-compilers.html    they can instead see and use simply   labouseur.com/course-compilers   (Even better, maybe I should restructure that so that it's courses/compilers.)  I'm using a Linux-based shared hosting service for my website, so I do not have administrative control of the server, but I do have control over .htaccess. The references I've read online seemed less than clear to me, so I'm looking for a little clarity and advice here.


Calculating the dropper / series resistor for an LED

I'm so sorry if this is a stupid question. I have read some of the questions previously asked but in afraid the maths and physics are way over my head.  I have made a wooden template and would like it to have light up eyes. I am hoping to use 1.5 V AA battery to power them. The eyes will be initially yellow LEDs. I don't want to fry them so if I wanted to power two separate 'eyes' which I believe are 2.1 V each, what resistor would I need to add to my circuit please? In the future, I may want to use other colours which are different voltages so if anyone can explain how to work this out in dummy terminology I would be incredibly grateful. Also, does it make any difference to the equation if you change the amount of LEDs being powered?


Trying to Free Up Space - Can I Delete Library Cache?

I'm trying to figure out how to free up some space on my MacBook. I downloaded Disk Inventory X, and in looking at the storage breakdown it provides, I see that my Library folder is 119.4 GB. Library > Caches inside there has 96.7 GB. Caches > Adobe has 93.1 GB. Looks like After Effects is taking up the most space in there with 92 GB. That seems like an insane amount of space for one program cache.   Also, Library > Application Support has 21.8 GB. And Application Support > Adobe has 20.2 GB.  What can I delete without messing up my computer? I use the Adobe Suite pretty much every day, so I don't want to screw it up.


Prove that for all rational number $a$ and $b$, $\frac{a+b}{2}$ ≥ $\sqrt{ab}$

Prove that for all rational numbers (can be integer) a y b, $\frac{a+b}{2}$ ≥ $\sqrt{ab}$


Suppress printing of only \bibentry references with natbib?

This question was , but I think that the only answer didn't quite understand the question so I thought I'd try again. I'm writing a paper in which I need to have references show up in two places:  a special list of "key references" in its own section, and a bibliography containing the rest of the references that were cited in the text. I thought that bibentry would do it, so the document looks something like: \documentclass[11pt]{article} \usepackage{natbib} \usepackage{bibentry} \nobibliography*  \begin{document}  \section{Amazing idea}  Chicken chicken chicken \citep{chicken:2010fj}.  Chicken chicken, chicken \citep{turkey:2010jk}.  \section{Key References}  \begin{enumerate} \item \bibentry{lemur:2009ii} \item \bibentry{gibbon:2011jk} \end{enumerate}  \bibliographystyle{apalike} \bibliography{amazing.bib} \end{document}  Unfortunately, this doesn't quite do it, as the resulting document presents the lemur and gibbon bibentry references correctly in the "Key References" section, but also prints them in the bibliography at the end of the document.  Ideally, the only entries in the bibliography would be the chicken and turkey \citep references.  I'd like it to look like:  Key references  Lemur, L. (2009). Lemur, 12(4):1-7. Gibbon, G. (2011). Gibbon, 135:1002-1009.  References Chicken, C. (2010). Chicken. Chicken Press, Coop. Turkey, T. (2010). Turkey, 7(4):E231.  What it actually looks like:  Key references  Lemur, L. (2009). Lemur, 12(4):1-7. Gibbon, G. (2011). Gibbon, 135:1002-1009.  References Chicken, C. (2010). Chicken. Chicken Press, Coop. Gibbon, G. (2011). Gibbon, 135:1002-1009. Lemur, L. (2009). Lemur, 12(4):1-7. Turkey, T. (2010). Turkey, 7(4):E231.  Is there any way to achieve this with the current method, or is there some other (possibly easier!?) way to do this?


I have to embed a contact form inside of a block, and I'm trying to use the entity.form_builder service, But I'm not sure which entity I should give it, I found Message and ContactForm entity, so what I'm thinking is to create a contact form entity and give it to the entityFormBuilder->getForm($contactFormEntity)  My current code is:  <?php   /**  * @file  * Contains Drupal\pid_contactform_block\Plugin\Block\TellUsYourStoryBlock  */  namespace Drupal\pid_contactform_block\Plugin\Block;  use Drupal\Core\Block\BlockBase; use Drupal\Core\Plugin\ContainerFactoryPluginInterface; use Symfony\Component\DependencyInjection\ContainerInterface;  /**  * Class TellUsYourStoryBlock  * @package Drupal\pid_contactform_block\Plugin\Block  * @Block(  *     id = "tell_us_your_story_block_id",  *     admin_label = "Tell us your story block",  *     module = "pid_contactform_block"  * )  */ class TellUsYourStoryBlock extends BlockBase implements ContainerFactoryPluginInterface {     protected $entityFormBuilder;  public function __construct(array $configuration, $plugin_id, $plugin_definition, $entityFormBuilder) {     parent::__construct($configuration, $plugin_id, $plugin_definition);     $this->entityFormBuilder = $entityFormBuilder; } /**  * Builds and returns the renderable array for this block plugin.  *  * If a block should not be rendered because it has no content, then this  * method must also ensure to return no content: it must then only return an  * empty array, or an empty array with #cache set (with cacheability metadata  * indicating the circumstances for it being empty).  *  * @return array  *   A renderable array representing the content of the block.  *  * @see \Drupal\block\BlockViewBuilder  */ public function build() {     return $this->entityFormBuilder->getForm();  }  /**  * Creates an instance of the plugin.  *  * @param \Symfony\Component\DependencyInjection\ContainerInterface $container  *   The container to pull out services used in the plugin.  * @param array $configuration  *   A configuration array containing information about the plugin instance.  * @param string $plugin_id  *   The plugin ID for the plugin instance.  * @param mixed $plugin_definition  *   The plugin implementation definition.  *  * @return static  *   Returns an instance of this plugin.  */ public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {     return new static(         $configuration,         $plugin_id,         $plugin_definition,         $container->get('entity.form_builder')     ); }   }  My question is basically:   Am i doing it the right way? How do I initialize the ContactForm entity correctly, if I am right, should I just import it or should I require it through a service or something? If I'm not right, do you have any idea how I should do it then?


Can I level up my Pokémon while they are at gyms?

I just dropped my Vaporeon off at the gym, but to my surprise, he can still be viewed in my Pokémon list! The buttons are there to level him up, but I'm not gonna be able to get any Eevee candy for a few hours to try. Can I level him up while he's in the gym?


How can I make a ComboBox non-editable in .NET?

I want to have a "select-only" ComboBox that provides a list of items for the user to select from. Typing should be disabled in the text portion of the ComboBox control.  My initial googling of this turned up an overly complex, misguided suggestion to capture the KeyPress event.


Is a ground required when replacing an old single pole single throw switch?

I need to replace a switch that controls a single light source in a bathroom.    The switch has two wires connected to it.  I bought a replacement switch that has two screws (one for each wire), and a green ground screw.  Is it OK to connect just the two wires to the new switch and have the green ground screw unconnected?  This is not a remodel.  Just trying to replace a switch that's broken.  EDIT: strangely, I didn't see a ground screw on the original switch.  Was this permissable at some time?  EDIT 2: Picture as requested.  The left switch is for a light source and is the broken one.  Right switch is for a fan.  The two switches are on the same circuit.  The outlet is on a separate circuit.  I can't tell if the box is metal.  It seems plastic but could be painted metal I suppose.    EDIT 3: With switches and outlet pulled out.


I am currently preparing my beamer presentation for my PhD defense.  I took the example at the url  to get a black board style presentation.  This template includes a short script which uses a random-generator to randomly scatter dust-trails on the black background to mimic chalk traces (see MWE below).  The thing is that parallel to that, I am also using overlays to uncover my slide layout by layout. The script is executed each time I am using a layout command which slows down the compilation quite substantially. I am not so familiar with control statements in latex, so here is my question:  How can-I modify this script for the background to be refreshed only when the slide is over, and not after each layout command?  Remarks:  1) I am using the Augie font, but I didn't included it in the MWE so that it can be compiled more easily  2) In case, it should make a difference I am also using the \begin{textblock*} \end{textblock*} environment from the textpos package to position text on the slide.  Here is my MWE:   \documentclass[10pt,mathserif]{beamer}  \usepackage[francais,english]{babel} \usepackage[utf8] {inputenc} %for ISOlatin1 (8859-1) sources \usepackage[T1] {fontenc}      %for polices DC 8bits   %%%Fancy fonts %\usepackage{emerald} %\usepackage{eulervm} %%%  %%Extra packages \usepackage{amsmath} \usepackage{amsfonts} \usepackage{tikz} \usetikzlibrary{arrows,shapes} \usepackage[absolute,overlay]{textpos}    %set text colors for different objects \setbeamercolor{frametitle}{fg=white} \setbeamercolor{structure}{fg=white} \setbeamercolor{normal text}{fg=white} \setbeamercolor{alerted text}{fg=white} \setbeamercolor{example text}{fg=white}   %%Black background \setbeamercolor{background canvas}{bg=black}    %%%%%%%%%%%%%%%%%%%%%% %%%%%Script: Random Dust Trails%%%%%%%%%%%%%%% \pgfmathsetseed{\number\pdfrandomseed} % seed for random generator \setbeamertemplate{background}{     \begin{tikzpicture}         \useasboundingbox (0,0) rectangle (\the\paperwidth, \the\paperheight);        \foreach \i in {1,...,30} {             \pgfmathsetmacro{\x}{random(0,10000)/5000-1}%             \pgfmathsetmacro{\y}{random(0,10000)/10000-0.1}%             \pgfmathsetmacro{\r}{random(0,10000)/1000-5}%             \rotatebox{\r}{                 \pgftext[at=\pgfpoint{\x\paperwidth}{\y\paperheight}, left, base]{\includegraphics[width=\textwidth]{paintstroke.png}}             }         };      \end{tikzpicture} } %%%%%%%%%%%%%%%%%%%%%%  %%No navigation bar \setbeamertemplate{navigation symbols}{}  \begin{document}      \begin{frame}          \begin{itemize}             \item<1-> bla slide 1             \item<2-> blu slide 1             \item<3-> blub slide 1         \end{itemize}      \end{frame}  %%I want the background to be refreshed with the Dust Trails script only at the end of the frame          \begin{frame}          \begin{itemize}             \item<1-> bla slide 2             \item<2-> blu slide 2             \item<3-> blub slide 2         \end{itemize}      \end{frame}  \end{document}   This is my first post, so please be kind if I did something illegal on the formatting of the message ;-).  Thanks in advance,  Yannick


Vector addition in speeds close to that of light

I've been studying special relativity and found a problem (at least for my limited knowledge): There's a car inside a train that is moving at speed $V_t$, for $V_t = 0.5c$. Once the car accelerates with $V_c = 0.5c$, from a reference frame other than those of the car and the train, does $V_t + V_c = c$?


Java object reference which points to another object reference

This class ds has two fields, x and y  public class ds {  private int x; private int y;  public ds(int xx, int yy) {     x = xx;     y = yy; }  public int getX() {     return x; }  public int getY() {     return y; }  public void setX(int xx) {     x = xx; }  public void setY(int yy) {     y = yy; }  }   This class ptrs uses ds to print results. I note that the printouts are the same whether int or Integer is used in ds.  public class ptrs { public static void main(String[] args)     {     ds d = new ds(1,2);      System.out.println("d.x:" + d.getX()); //1     System.out.println("d.y:" + d.getY()); //2      //t is an object reference (a pointer) which points to d, which in turn      points to the ds object     ds t = d;      System.out.println("t.x:" + t.getX()); //1     System.out.println("t.y:" + t.getY()); //2      t.setX(3);     t.setY(4);      System.out.println("");      System.out.println("t.x:" + t.getX()); //3     System.out.println("t.x:" + t.getY()); //4       System.out.println("d.x:" + d.getX()); //3     System.out.println("d.y:" + d.getY()); //4      d.setX(5);     d.setY(6);      System.out.println("");      System.out.println("d.x:" + d.getX()); //5     System.out.println("d.x:" + d.getY()); //6      System.out.println("t.x:" + t.getX());  //5     System.out.println("t.x:" + t.getY());  //6     } }   When I call the set methods on either d or t, calling the get methods on either pointer results in the updated values. Why is there apparently different behavior in the next example?  public class main     {     public static void main(String[] args)         {         Integer i = new Integer(5);         Integer a = i;          System.out.println("i is " + i ); //5         System.out.println("a is " + a ); //5          i = new Integer(10);          System.out.println("i is " + i ); //10          System.out.println("a is " + a ); //5         }     }   If I set an Integer object reference i to point to an Integer object with value 5, and then make another reference a refer to i, why does a still point to 5 even after I make i reference another Integer object with value 10?  Is the difference because in the first example I change fields of the same object, but in the second example I point to a new object? But why would that cause a difference, if that is the reason..?


I downloaded the Popcorn-Time from official link. When I try to execute "Popcorn-Time" file, using ./Popcorn-Time, it outputs the following error:  error while loading shared libraries: libudev.so.0: cannot open shared object file: No such file or directory   I've tried installing libudev0 by using:  apt-get install libudev0:i386   But that outputs the following error:   E: Package 'libudev0:i386' has no installation candidate   The image below contains all extracted files from .tar:   Anyone knows how I can execute Popcorn?


Consider a dataframe ("df") with three variables (Happiness, Smoke, Depression), where (1) Happiness (DV) = continuous measure of happiness on 1-10 scale, (2) Smoke (IV1) = categorical variable of whether the person smokes (yes/no), and (3) Depression (IV2) = continuous measure of depression on 1-10 scale. Happiness <- c(1, 2, 5, 6, 2, 7, 7, 3, 8, 9) Smoke <- c("yes", "yes", "no", "no", "yes", "no", "yes", "yes", "no", "no") Depression <- c(6, 8, 2, 1, 10, 4, 5, 1, 2, 3) df <- data.frame(Happiness, Smoke, Depression)  Suppose I want to test whether Smoke x Depression interaction predicts Happiness (in other words, if the interaction between two Independent Variables predicts the Dependent Variable). So I use this formula: summary(lm(data = df, Happiness ~ Smoke*Depression))  which gives me this: Call: lm(formula = Happiness ~ Smoke * Depression, data = df)  Residuals: Min      1Q  Median      3Q     Max  -2.0000 -1.0460 -0.3788  0.8905  3.7826   Coefficients:                     Estimate Std. Error t value Pr(>|t|)   (Intercept)           5.6154     2.4745   2.269   0.0637 . Smokeyes             -1.3110     3.2748  -0.400   0.7028   Depression            0.5769     0.9489   0.608   0.5655   Smokeyes:Depression  -0.7943     1.0011  -0.793   0.4578   --- Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1  Residual standard error: 2.164 on 6 degrees of freedom Multiple R-squared:  0.6098,    Adjusted R-squared:  0.4147  F-statistic: 3.125 on 3 and 6 DF,  p-value: 0.1092  I need help interpreting this result.  Is it correct to use Smoke*Depression instead of Smoke + Depression, or Smoke:Depression if I want to see the main effect of each independent variable and their interaction? Do the values under Pr(>|t|) mean the significance of main effect for each variable? If so, how do I test the main effect of non-smokers? (ie, why is there only "Smokeyes" and no "Smokeno"?) What does Smokeyes:Depression indicate? I am suspecting that it means the interaction between Smoke and Depression. If so, how is Pr(>|t|) of this different from the p-value?  Any help would be much appreciated. Thank you!


Python’s for statement iterates over the items of any sequence (a list or a string).  But where does the sequence come from in below code?  file=open('filename.txt','r') for line in file:     print line   Is this related to the __iter__() method?  Just some quote:       An object capable of returning its members one at a time. Examples of iterables include all sequence types (such as list, str, and tuple) and some non-sequence types like dict, file objects, and objects of any classes you define with an __iter__() or __getitem__() method. Iterables can be used in a for loop and in many other places where a sequence is needed (zip(), map(), ...). When an iterable object is passed as an argument to the built-in function iter(), it returns an iterator for the object. This iterator is good for one pass over the set of values. When using iterables, it is usually not necessary to call iter() or deal with iterator objects yourself. The for statement does that automatically for you, creating a temporary unnamed variable to hold the iterator for the duration of the loop. See also iterator, sequence, and generator.


How to Calculate F distribution given R squared?

After some research, I find that the relationship between $R^2$ and the F distribution is as follows:  $$ R^2 = 1 - (1 + F \cdot \frac{p-1}{n-p})^{-1} $$  But I am not sure what the $p$ and $n$ values should be. Suppose my $R^2$ is calculated from 10 values of $x$ and $y$, what would $p$ and $n$ be?  Thanks!  EDIT: don't think it's a duplicate because my question is more basic, i.e. what $p$ and $n$ values are.


How to prove that center of $GL_n(\mathbb R)$ is scalar matrices?  Again what can you say about the center of set of all upper triangular matrices and center of set of all diagonal matrices.


I am trying to power off and power  on  usb port in Ubuntu 12.04 without success.    I tried the steps listed below:  echo "0" > "/sys/bus/usb/devices/$port/power/autosuspend" echo "auto" > "/sys/bus/usb/devices/$port/power/level"   and    echo "auto" > "/sys/bus/usb/devices/2-1.3/power/control"  echo "0" > "/sys/bus/usb/devices/2-1.3/power/autosuspend_delay_ms"   and   echo suspend | sudo tee /sys/bus/usb/devices/XXXX/power/level


converting list of object to array in c# - what does the "x => x.Name" syntax mean?

I was looking for a solution to convert each object's properties on a List to some arrays when finally I found   Then I found this code  MyList.Select(x=>x.Name).ToArray();   which is the solution to my problem. But I still don't understand on what the variable 'x' means. can anyone could explain to me briefly on how this syntax work?


I'm a web developer, started to become a web designer. However, I think my understanding of colors is not practical yet. There are tools out there that can give you color harmonies, and more stuff, like , but they don't give you the start point. I mean, how should I know that for this web site, I'd better use green and for that website, choose red. How should I know that?  I think color selection is more like an art, instead of being a science, and I'm like "you should become an color artist, in order to become a web designer".  How can I improve my color selection skill?


Move emails from from Deleted Items back to their orginal folders

Someone I know went into the Large Emails "folder" and cleared it out thinking that those were just duplicates. She didn't realize that she was actually deleting the emails from her many folders.  Now, all the emails are in her Deleted Items folder. Since they came from several different folders, reorganizing them back to those folders is going to be a major task.  Is there any way in Outlook 2010 to select all the emails at once and tell it to move them back to the folders they were orginally in? This in a stand-alone environement (no Exchange Server).


problem when using += in setInterval to continually increment a variable

here are two questions about the exercise that I am doing for practicing of setInterval fuction   from following code, I tried to print out the variable which is self-adding by 10 within 1000 milliseconds, but when I ran it, in the console of browser, it only showed 10 times of same word "num", how do I figure it out ?      $(function() {   var timmer;   GoCount();    function GoCount() {     timmer = setInterval(function() {       var num = 0;       num += 10;       console.log(num);     }, 1000);   } }); <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>      and the second question is what's the difference between setInterval and for loop


I know this has been asked around, my question is a bit more specialized towards my personal problem.  If I have an object the magnitude of the weight is usually equal to the normal force, right?   I could be mistaken but from what I have read the normal force is the force the object is feeling opposite to the $(mass*gravity)$. If that is the case, and I put my hand on the object does my Force get added to the object's weight and thus the normal force of that object increases? Therefore if I keep adding hands to the object will the normal force keep compensating?   Also is the normal force the negative charged electrons repelling each other (electromagnetism)?


How can an xinput command be run automatically when the system is started in Ubuntu 18.04?

I want this command to be executed automatically when my machine starts   xinput set-prop "AlpsPS/2 ALPS DualPoint Stick" "Device Enabled" 0   How can I do this?


I'm the sole author of a paper and in my introduction I've written:     We are able to talk about... Doing so we manage to capture ... We accomplish this by embedding...   and I'm wondering whether it's correct to talk about myself in the plural like that, similar to the way that mathematicians tend to write when talking about some mathematical fact or proof. If not do I just write things like "I am able to talk about"? Because that just sounds odd.


No wireless capabilities on menu bar after fresh 16.04 LTS install

I'm very new to Ubuntu again, I haven't touched it since Desktop 13, and I will need some hand-holding here. I can't connect to a network. I've been frustrated trying to find a solution to here and I've mashed more code through terminal than I'd like to admit. Would anyone be willing to help me solve this? I will do my best to answer any questions I can.


I'm currently trying to get the basics of Pytorch, playing around with simple networks topologies for the fashion-MNIST dataset.  However, when I record the loss of those models after each epochs, it seems its going up rather than going down. Here is a graph of those series :   You can find my code in this repo :   Moreover, the fact that the more "advanced" the networks I try to implement, the lossier it gets over the 50 epochs (Net4 should've been the conclusion of the learnings in the previous ones).  Interestingly, the accuracy of those nets seems to not reflect this loss going up. The 3rd networks performed the best with a final accuracy of around 92%, and the 2 firsts were around 90%. Last one got 89%.  I thought at first that it may be a problem of vanishing gradient, but using leaky relu activation function I thought this problem wouldn't appear. This is strange because the network 1 uses the sigmoid activation function and it outperform the leaky relu of network 2.  If anyone knows what is happening it would be a great help ! :)  Thanks


Attempt to re-install ubuntu-software fails: "no installation candidate"

For some reason my ubuntu-software-center disappeared (on Ubuntu 18.04).  I tried the usual   sudo apt-get update   and   sudo apt-get install software-center   But I end up with this error:  Package software-center is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  E: Package 'software-center' has no installation candidate   How can I solve this issue? I tried with synaptic but it did not work out.


$T$ self-adjoint on Hilbert space $H$, $T^n=T^{n+1}$ will $T$ be an orthogonal projection operator?

I have seen several answers and proofs here at MSE that a self-adjoint operator $T$ on a Hilbert space $H$ where $T^2=T$, implies $T$ being an orthogonal projection operator.   The thought struck me; what would happen if the condition $T^2=T$ is replaced by $T^3=T^2$ or instead by $T^4=T^3$ or why not more generally by $T^n=T^{n+1}$ for some $n\in\mathbb{N}$? Would this still imply $T$ to be an orthogonal projection operator?  I guess someone must have thought of this before me? In that case perhaps there is a reference in the literature for this or perhaps the proof is way simpler than I might expect?


Constructing Idempotent Generator of Idempotent Ideal

Exercise 2.1 in Matsumura's Commutative Ring Theory reads as follows: "Let $A$ be a commutative ring and $I$ an ideal that is finitely generated and $I=I^2$. Then $I$ is generated by an idempotent."   In trying to solve it, i first followed a constructive approach, where e.g. for the case of two generators i tried to construct an idempotent generator. However, it seemed difficult. Then i realized that i could apply Nakayama's lemma to the $A$-module $I$ and the existence of the idempotent generator follows.   My question is: How could one go about finding this idempotent generator? Is there a systematic way?


Does Great Weapon Fighting allow the SRD version of a Vicious Weapon's 2d6 bonus to be rerolled?

Does Great Weapon Fighting style allow Vicious weapons 2d6 bonus to be rerolled? Is it considered weapon damage? I know similar questions have been asked but need to know for this exact circumstance. (Note: this question concerns the SRD version of a Vicious Weapon. The Vicious Weapon published in the Dungeon Master's Guide adds a flat 7 damage, rather than 2d6)


Same tikz. Two matrices. (Diagram legend)

could not figure out an answer to this one.  I have a tikz diagram using tikz/matrix, and I want to have a legend next to it, also using tikz/matrix. But I do not know how to refer to one particular matrix in the style definitons.  Let me visually show the problem:  \documentclass{article}  \usepackage{tikz} \usetikzlibrary{     positioning,     shapes.geometric,     matrix}  \begin{document}  \begin{tikzpicture} \tikzset{     status/.style={rectangle, draw=black, text centered, anchor=north, text=black, minimum width=2em, minimum height=2em},     mstyle/.style={column sep=10em, row sep=3em,nodes={status},font=\bfseries},     line/.style={draw,thick,-latex},     row 1 column 1/.style={nodes={fill=green}},     row 1 column 2/.style={nodes={fill=red}},     row 1 column 3/.style={nodes={fill=yellow}},     row 2 column 3/.style={nodes={fill=gray}},     row 2 column 2/.style={nodes={diamond}}, } \matrix(m)[matrix of nodes,ampersand replacement=\&,mstyle]{     H \& A1 \& A2 \\       \& {} \& D \\ }; \tikzset{     status/.style={rectangle, draw=black, text centered, anchor=north, text=black, minimum width=2em, minimum height=2em},     m2style/.style={column sep=1em, row sep=1em,nodes={status},font=\bfseries}, } \matrix(m2)[right=of m, draw=black, matrix of nodes,ampersand replacement=\&,m2style]{     H  \& Healthy \\     A1 \& Infected  \\     A2 \& Infected  \\     D \& Death  \\ }; \draw[line] (m-1-1) -- (m-1-2) node[pos=0.5,above,align=left] {$\#\mathrm{A1} \geq 1$ or\\$\#\mathrm{A2} \geq R$}; \draw[line] (m-1-2) -- (m-1-3) node[pos=0.5,above] {wait $\tau$ ticks}; \draw[line] (m-1-3) -- (m-2-3) node[pos=0.5,right] {wait 1 tick}; \draw[line] (m-2-3) -- (m-2-2) node[pos=0.5,above] {$p_\mathrm{replenished}$}; \draw[line] (m-2-2) -| (m-1-1) node[pos=0.2,above] {$1-p_\mathrm{infected}$}; \draw[line] (m-2-2) -- (m-1-2) node[pos=0.5,left] {$p_\mathrm{infected}$}; \end{tikzpicture}  \end{document}   I want tikzset to be limited to the scope of the first matrix m ....


What Hogwarts classes are taught to two houses at once?

I remember from my mumble about nine mumble rereads of the Harry Potter series that the following classes Harry took were taught to more than one house in the same lesson:   Potions with the Slytherins  Herbology with the Hufflepuffs  Care of Magical Creatures with the Slytherins  broomstick riding with at least the Slytherins (maybe other houses, too?)    I don't remember any student from a house that isn't Gryffindor being mentioned in the sections on Transfiguration, Charms, Defense Against Dark Arts, History of Magic, or Divination. That would mean McGonagall had to teach twice as many classes as Snape, if both subjects got the same number of lessons (which I think I recall).   Were any subjects other than Potions, Herbology, and Care of Magical Creatures taught to more than one house in the same lesson? And do we know why some subjects are taught to more students at the same time than others?


Use std container iterator in template class

I can't use the std container iterator in a template class.  I get this errors : error C2061: syntax error : identifier 'iterator' error C2238: unexpected token(s) preceding ';'  Here the source code:  #include <list> #include <functional> #include <memory>  template<typename TParam> class MyClass { public:     using TFunction = std::function<void(TParam)>;     using TContainer = std::list<TFunction>;     using TIterator = TContainer::iterator; // compilation error here! };   How to use the iterator of the container in the templated class?


Prove that $x^2 + y^2 = 3(z^2 + m^2)$ has no solutions in integer

Prove that: $$  x^2 + y^2 = 3(z^2 + m^2)  $$ has no solutions in integer Except $0 0 0 0$


While writing down an algorithm, I've come to the following construct:     There are multiple for/if/while's before this one so it is quite indented.  Example code:  \usepackage{algpseudocode,algorithm,algorithmicx} \begin{document} \begin{algorithm} \begin{algorithmic}[1] \If{true} \If{$interval.start - error_{early} \leq timestamp + error_{late}$ {\bf and} $timestamp - error_{early} \leq interval.end + error_{late}$} \State \Return{$false$} \EndIf \EndIf \end{algorithmic} \end{algorithm} \end{document}   The If line is too long an I would like to break the line before or after the and. Linebreaking with \\ does not work.


I have lots of mods installed on my Minecraft client. How can I make certain mods only work in certain worlds?  For example, how can I make the train mod work only for one of my worlds not the others and have BuildCraft work for all my worlds except the one with the train mod?


i have exceed number error in nextInt() of util.Random in Java 1.8.74 (Intellij Idea 2016.1.1)

I tried to get a random number between 3 and 6 (inclusive):  public class A {                 Random ran = new Random();                              public func1(){               x = 3 + ran.nextInt(7); // need Random number x from 3 to 6      y = 3 + ran.nextInt(7)               } }       but it often gives results 8 and 9! How it can be ?  I used     x=(int) (3 + Math.random()*6);     its give 8 sometimes too... where is an Error???


How can I create a Continued Figure Caption?

I have two figures with somehow the same caption, see the code:  \begin{figure}[!ht]\centering \includegraphics[height=18cm]{pic1} \caption{caption} \end{figure} \addtocounter{figure}{-1} \begin{figure}[!ht]\centering \includegraphics[height=18cm]{pic2} \caption{(continued)} \end{figure}   Is there a way to have only the first figure referenced in the list of figures?


How would I change the following code (outJPEG section) if I'd like to have the original attribute table name (eg Adress) and the attribute field name (eg ZipCode) as file name? (Adress_ZipCode)  The code as I have it now would just name the output JPG after the field in the attribute table (ZipCode)  Maybe os.path.split is an option but I am not so familiar with python and cannot make it work..  # export as jpeg  outJPEG = os.path.join(outPath, attr + ".jpg")  #atrr and outPath are defined in another part of the code arcpy.mapping.ExportToJPEG(mxd, outJPEG, "PAGE_LAYOUT", 200, 200, 300, False, "24-BIT_TRUE_COLOR", 90, False)


T-SQL: Opposite to string concatenation - how to split string into multiple records

Possible Duplicate:          I have seen  in SQL. I wonder how would you approach the opposite problem: splitting coma delimited string into rows of data:  Lets say I have tables:  userTypedTags(userID,commaSeparatedTags) 'one entry per user tags(tagID,name)   And want to insert data into table  userTag(userID,tagID) 'multiple entries per user   Inspired by  question  EDIT  Thanks for the answers, actually more then one deserves to be accepted but I can only pick one, and the  with recursions seems pretty clean to me. It works on SQL Server 2005 and above.   For earlier version of SQL Server the solution  can be used.  For working with text data type  will be helpful. Thanks again.


How come the protected internal field gets the access when its between two assemblies?

I have Created Two Class Library projects (AssemblyA and AssemblyB) to distinguish the difference between the protected and protected internal access modifiers.  I have made a reference of AssemblyA in AssemblyB and used the Using Directive in the code of AssemblyB.  Class Library Project (AssemblyA)  using System;  namespace AssemblyA {     public class AClassA     {         protected int ID;         protected internal int Age;     } }   Class library project (AssemblyB)  using System; using AssemblyA;  namespace AssemblyB {     public class BclassA : AClassA     {         public void print()         {                        this.ID = 1;             this.Age = 22;              // I can access both these fields here.             // How come the protected internal field gets the              // access when its between two assemblies?         }            } }


How can I stop apps I do to not want appearing in the dock?

I have got into system preferences and there is no recents uncheck. How do I stop app icons from sticking in the dock?


I read about Rutherford's failed attempt to describe the atomic model. Then I read about Bohr's model and his postulates. Ok, that was fine. But then I read in my book  a statement that shocked me:     One and the most important discovery of quantum mechanics was that electron behaves as wave....   Now, how can an electron, a particle revolving around the nucleus in a quantized orbit, be a wave?


What constitutes an object when using teleport?

There doesn't seem to be a weight limit on teleport anymore but, for the purposes of looting a dungeon, what is an object?  I can see how you can fill a chest and then teleport the chest and its contents. It is container and so all its contents are also teleported.  How about a 10' long table stacked with gear? Is the table also a container in the same way or would teleporting a table not teleport the tablecloth?


Take a random card of a deck. Let A be the event that the card is hearts. Let B be the event that the card is a king, queen, or ace. Are these events independent? Standard deck of 52, no jokers.  I say yes they are independent. Event A is not dependent on event B when getting a card from the deck.  My question is, what are your thoughts on my conclusion?


Can I report my math GPA instead of major (CS and math) GPA when applying to graduate school?

So I'm a combined Math/CS major wanting to do grad school for pure math. My GPA my first 3 semesters was terrible, and I got my shit together after that.  While I have all A's in math courses, my major GPA would include CS courses as well, and those are my worst grades. I estimate I can't raise it above 3.5 by next December.  I would like to know if I have any flexibility in how I report my GPA, i.e. if I can report a math GPA instead of a major GPA.


I'm trying to remember the author and title of a short story about the Earth in the far future which is visited by an enormous creature (maybe like a continent sized salamander) which devastates the world but is worshipped by the people. It returns periodically with earth-shattering consequences. Any ideas?


Position of only in a sentence and meaning?

OK, so I fall down on this one sometimes, but here goes, what sentence means which?  from my geography paragraph;  Only East Anglia was voted the most coastal part in the North London commuter belt.  East Anglia was only voted the most coastal part in the North London commuter belt.  East Anglia only was voted the most coastal part in the North London commuter belt.  East Anglia was voted only the most coastal part in the North London commuter belt.  East Anglia was voted the only most coastal part in the North London commuter belt.  East Anglia was voted the most coastal part in only the North London commuter belt.  East Anglia was voted the most coastal part in the only North London commuter belt.  East Anglia was voted the most coastal part in the North London commuter belt only.  and from my car paragraph - two separate sentences;  Only Renault sold 1,450 vehicles of MPV and 8,000 of commercial vehicles in total last year. Renault only sold 1,450 vehicles of MPV and 8,000 of commercial vehicles in total last year. Renault sold only 1,450 vehicles of MPV and 8,000 of commercial vehicles in total last year. Renault sold 1,450 vehicles of MPV and 8,000 of commercial vehicles only in total last year. Renault sold 1,450 vehicles of MPV and 8,000 of commercial vehicles in total only last year. Renault sold 1,450 vehicles of MPV and 8,000 of commercial vehicles in total last year only.  Another paragraph.  Only in Europe, Toyota offers the Camry as the 2.5 GL or 3.5 V6 GLX sedan.  In Europe only, Toyota offers the Camry as the 2.5 GL or 3.5 V6 GLX sedan.  In Europe, Toyota only offers the Camry as the 2.5 GL or 3.5 V6 GLX sedan.  In Europe, Toyota offers the Camry only as the 2.5 GL or 3.5 V6 GLX sedan.  In Europe, Toyota offers only the Camry as the 2.5 GL or 3.5 V6 GLX sedan.  In Europe, Toyota offers the Camry as only the 2.5 GL or 3.5 V6 GLX sedan.  In Europe, Toyota offers the Camry as the 2.5 GL or 3.5 V6 GLX sedan.  And finally, my fourth sentence, which is:  Only John worked with Jane on a Monday when he went off-site.  John only worked with Jane on a Monday when he went off-site.  John worked only with Jane on a Monday when he went off-site.  John worked with only Jane on a Monday when he went off-site.  John worked with Jane on only a Monday when he went off-site.  John worked with Jane on a Monday when only he went off-site.  John worked with Jane on a Monday when he went off-site only.  John worked with Jane on a Monday when he went only off-site.  I'd appreciate any help in ensuring that my sentences read the way I intended, thanks! ;)


How do I restore my contacts list to the left side of my Gmail?

I want to restore my contacts in the left side of my emails and not separate on the right corner.


I'm running Ubuntu 12.04 LTS on a Samsung Chronos 7 laptop. The computer was running fine, until recently after a required reboot, the screen was black showing:  "error: hd0 out of disk grub rescue>"  I have absolutely NO IDEA what's going on here AT ALL. I've read that it has to do with conflicting partitions, but I'm 99% sure that I deleted the entire hard drive of any existing partition when first installing Ubuntu. Does anybody have a clue?


Broadcom Wireless Drivers unclaimed after installing update 16.04

I recently updated my Lenovo Y50 computer to 16.04. Since the update, I have been unable to see or connect to any wireless networks. The output of running sudo lshw -C network is:     *-network UNCLAIMED          description: Network controller          product: BCM4352 802.11ac Wireless Network Adapter          vendor: Broadcom Corporation          physical id: 0          bus info: pci@0000:08:00.0          version: 03          width: 64 bits          clock: 33MHz          capabilities: pm msi pciexpress cap_list          configuration: latency=0          resources: memory:d1600000-d1607fff memory:d1400000-d15fffff   The fact that the wireless network controller is unclaimed leads me to believe that this is a driver related issue. I have checked and made sure that "Use proprietary driver" is checked in System Settings > Software & Updates > Additional Drivers and I have run sudo apt-get install --reinstall bcmwl-kernel-source I have also restarted after every driver change to finish the changes. Is there anything else I should try?  EDIT: Here is the result of running lspci -nnk | grep 0280 -A2:        08:00.0 Network controller [0280]: Broadcom Corporation BCM4352 802.11ac Wireless Network Adapter [14e4:43b1] (rev 03)     Subsystem: Lenovo BCM4352 802.11ac Wireless Network Adapter [17aa:0623]     Kernel modules: bcma, wl   Running sudo modprobe wl && dmesg | grep wl returns an error:      modprobe: ERROR: could not insert 'wl': Required key not available


Can anyone explain this unexpected behavior?    console.log(new Date() == new Date()); // false console.log(new Date() >= new Date()); // true console.log(new Date() <= new Date()); // true


How can I calculate the difference of 2 counters (pageref)?

How can I calculate the difference between 2 counters (like page numbers), so that pdfLateX outputs "3" in the last line of my example? and how could I calculate the difference between the "current" page (where the calculation is printed) and \pageref{A} (without explicitly defining \label{B})?   Example:  \documentclass{scrbook}  \usepackage[ngerman]{babel}  \usepackage[latin1]{inputenc}  \begin{document}  Here is label A \label{A}  \newpage text \newpage text \newpage  Here is label B \label{B}  There are \pageref{B}-\pageref{A} pages between labels A and B.   \end{document}


General formula or a pattern for the $n$th derivatives of $e^{f(x)}$?

I want to find the $nth$ derivatives of the function $e^{f(x)}$ with respect to $x$, the first derivative is $$e^{f(x)}f^{\prime}(x).$$  The second derivative is $$\left( {\frac {d^{2}}{d{x}^{2}}}f \left( x \right)  \right) {{\rm e}^ {f \left( x \right) }}+ \left( {\frac {d}{dx}}f \left( x \right)   \right) ^{2}{{\rm e}^{f \left( x \right) }} .$$ The third derivative is $$\left( {\frac {d^{3}}{d{x}^{3}}}f \left( x \right)  \right) {{\rm e}^ {f \left( x \right) }}+3\, \left( {\frac {d^{2}}{d{x}^{2}}}f \left( x  \right)  \right)  \left( {\frac {d}{dx}}f \left( x \right)  \right) { {\rm e}^{f \left( x \right) }}+ \left( {\frac {d}{dx}}f \left( x  \right)  \right) ^{3}{{\rm e}^{f \left( x \right) }} $$  The fourth derivative is $$ \left( {\frac {d^{4}}{d{x}^{4}}}f \left( x \right)  \right) {{\rm e}^ {f \left( x \right) }}+4\, \left( {\frac {d^{3}}{d{x}^{3}}}f \left( x  \right)  \right)  \left( {\frac {d}{dx}}f \left( x \right)  \right) { {\rm e}^{f \left( x \right) }}+3\, \left( {\frac {d^{2}}{d{x}^{2}}}f  \left( x \right)  \right) ^{2}{{\rm e}^{f \left( x \right) }}+6\,  \left( {\frac {d^{2}}{d{x}^{2}}}f \left( x \right)  \right)  \left( { \frac {d}{dx}}f \left( x \right)  \right) ^{2}{{\rm e}^{f \left( x  \right) }}+ \left( {\frac {d}{dx}}f \left( x \right)  \right) ^{4}{ {\rm e}^{f \left( x \right) }} $$  My question is: Is there a general formula or a pattern for the nth derivative of $e^{f(x)}$. You may use the maple command diff(exp(f(x)), x$5) to do some experiments. Thanks a lot ^^


Automating DB Restore from network share

We have a network share that uses different credentials from the currently logged in user. Inside this share we have full, differential and log backups that come through from a third party database that are updated daily.  I've been tasked with automating the restoration of these backups to a local database.   What's the best way to go about designing and implementing a solution for this?  Folder Structure    Log File structure  As can be seen above, there are multiple files in each folder with different file names depending on the date, etc.   Update:  Following on from the solution posted below, I had to modify the suggested PowerShell code slightly in order to make it work:  $pass ="xxx"|ConvertTo-SecureString -AsPlainText -Force $cred = New-Object System.Management.Automation.PsCredential('Domain\Account',$pass)  New-PSDrive -Name K -PSProvider "FileSystem" -Credential $cred -Root '\\UNC PATH TO FOLDER WHERE BACKUP IS STORED'; Get-PsDrive;  Copy-Item K:\ -Recurse M:\DESTINATION;  Restore-DbaDatabase -server MRVAPPSQL01 -path M:\DESTINATION -MaintenanceSolutionBackup -WithReplace;  Remove-PSDrive -Name K;  Remove-Item M:\DESTINATION\*.*;


How do you thing I could write this type of function in Latex? I don't know how to make functions like in the picture. Thank you!


Exponential Family distribution with non-open natural parameter space?

Is there any example of canonical exponential family distribution with a natural parameter space, that is not open? An $k$ dimensional canonical exponential family means having a p.d.f (w.r.t base measure $u(dx)$)$$\exp\{T'\eta\}c(\eta),$$ where $T\in\mathbb{R}^k$ is the sufficient statistic and $\eta$ is the natural parameter. A natural parameter space is defined as $$\Xi=\left\{\eta\in\mathbb{R}^k: \int\exp\{t'\eta\}u(dt)<\infty\right\}$$ I wonder if there is any canonical exponential family distribution having $\Xi$ being a non-open set in $\mathbb{R}^k$? By the way, this is NOT a duplicated question.


Understanding the math behind linear discriminant analysis

I am trying to understand  paper. It uses PCA and further uses LDA for dimensionality reduction.   I have read about eigenfaces and PCA approach but I am not familiar with LDA and I am unable to understand the mathematics behind the scatter matrices : why to minimize the determinant of projected scatter matrices and how we perform it.   Can anyone explain the maths behind LDA and how the generalized eigenvalues come into picture or point to some related tutorial where I can understand the approach?


How to collect list of tuples into one tuple in Python?

I think this should be a no brainer, but I'm kinda lost. If I have a list of tuples:  l = [(1, 2), (3, 4), (5, 6)]   how do I put all the values from the tuples into one list so that the result is this:  [1, 2, 3, 4, 5, 6]   I guess I need to use list comprehensions, but I'm unsure how.. All tips are welcome!


Dual booting WIndows 8.1 and Ubuntu 14.04 with UEFI on a system that isn't preinstalled?

I'm interested in dual booting Ubuntu 14.04 alongside my copy of Windows 8.1. The copy of Windows 8.1 is NOT preinstalled, as I built the PC my self, and it is a retail stock version of Windows 8.1. Could someone please help me with this?


awk conditional reformat redirect to infile

I have a csv file as below, and my goal if conditions met(first column equals "emre" an second is "3" ) first column value will be set to "emretest", I did it but I need to do it with infile option. csv file  awk -F\; '{ $1 = ($1 == "emre" && $2== 3 ? $1 = "emretest" : $1) } 1' OFS=\; input.txt


Getting the source code any URL with JavaScript

There have been occasions where I have desired to retrieve the HTML of pages other than the one I am typically on. This has happened either when I am using a browser's JavaScript console or when I am writing a bookmarklet. So, given any URL, I wish to retrieve the content of that URL so that I may then use it in, say, a JavaScript variable.  The desired solution cannot use jQuery since that requires loading an external library, which is only optimal in the context of JavaScript that is running in a webpage (as opposed to a console or from a bookmarklet). (Also, adding a script tag to a page just to use in the console is clunky.)


.htaccess created or modified: do I have to restart Apache?

I am trying to debug some .htaccess problems on Apache but I am new to mod_rewrite.c. I would like to know whether I need to restart Apache in XAMPP whenever I make modifications to the .htaccess files, or whether these are parsed and applied whenever a web page is served independently of whether Apache is restarted.


Story Identification: Short story about a man waking up and realizing he has an API to his body

It's a fairly fast read but I forgot the name.  Guy wakes up in a hospital/military facility by a computer.  Realizes he has an API into his own body.  Programs himself to get stronger which takes up energy so he gets hungry and eats a lot.  Then some stuff about memory/encrypting huge keys in his head.  Thanks in advance!


Determinant of $2 \times 2$ block matrix with commuting blocks

Let $A,B,C$ and $D$ be $n \times n$ matrices such that $AC = CA$. Prove that $$\det \begin{pmatrix} A & B\\ C & D\end{pmatrix} = \det(AD-CB)$$   The solution is to first assume that $A$ is invertible and then consider the product $$\begin{pmatrix} I & O\\ -CA^{-1} & I \end{pmatrix}\begin{pmatrix} A & B\\ C & D \end{pmatrix}=\begin{pmatrix} A & B\\ O & D-CA^{-1}B \end{pmatrix}$$ then it is not hard to prove that the claim is true if $A$ in invertible. Finally, we use the fact that the set $GL_n$ form a dense open subset of $M_n$ to get rid of the invertibility assumption. My question is: how to come up with such a weird matrix $\begin{pmatrix} I & O\\ -CA^{-1} & I \end{pmatrix}$? thank you so much. Is there any other problems that uses the technique of assuming invertibility? (one of which i know is to prove $\det (I+AB) = \det(I+BA)$), thanks in advance


How to exclude certain widget from showing up on home/front page?

Without using a plugin, how do I prevent/exclude the sidebar widget "recent posts" from showing up on the home/front page?  I do want it to show on the sidebar of rest of other archive/post pages.


Share folders between windows and ubuntu in Virtualbox

Possible Duplicate:          I use virtualbox. My host OS is Ubuntu and the guest one is Windows XP. I want to share a folder between these two OS. But I don't know how. I've added the folder on 'Devices->Shared Folders' window but I don't know how to access it from Windows .  Would you help me?  Thank you.


Can't find information on it, since don't know what it is actually. This is what I have in Rendered Viewport Shading:    And this is what Render shows me as an result:    So, what are these vertical lines? Seems like something wrong with UV, but why then Viewport shows everything ok? I mean, I'm pretty noob in blender, so I don't have any idea.


Are orbits equal if and only if stabilizers are conjugate?

Let $X$ be a topological space and $G$ a group acting on $X$.  Do we have this property:  $$\operatorname{orb}(x)=\operatorname{orb}(y)\iff\operatorname{stab}(x)\sim \operatorname{stab}(y)\qquad ?$$ where $\operatorname{orb}(x)$ is the orbit of $x$, $\operatorname{stab}(x)=\{g\in G\mid gx=x\}$, and the symbol $\sim$ means conjugate to.  One way is obvious: if $\operatorname{orb}(x)=\operatorname{orb}(y)$, then $x=gy$ for some $g\in G$, so $$\operatorname{stab}(x)=\operatorname{stab}(gy)=g\operatorname{stab}(y)g^{-1}.$$ But the other way is not obvious to me: if $\operatorname{stab}(x)\sim \operatorname{stab}(y)$, then $\exists k\in G$ such that for all $g\in \operatorname{stab}(x)$,  $ \exists h \in \operatorname{stab}(y)$ such that  $g=khk^{-1}$. Now since $gx=x$ and $hy=y$, then $khk^{-1}x=x$ so $hk^{-1}x=k^{-1}x$ hence $h\in \operatorname{stab}(k^{-1}x)$, but I can't go any further... Thanks for your help.


downloading event log file from apex code

Can we download the event log file directly from apex code.(i.e., without using rest explorer/webservices manually.Everything should be written in Apex code only).  Regards, Sravika


Adding a command to LaTeX file using texify

A program I am using spits out LaTeX tables in LaTeX files (outreg2 command from Stata), which I run using texify to make pdfs of the tables.  I crop these tables (using pdfcrop) and embed them elsewhere.  However, the pdfs include page numbers, which prevent pdfcrop from cropping directly around the table.  I need an automatic way to remove the page numbers before cropping.  I want to insert the command \pagenumbers{gobble} into the LaTeX code to automatically remove the page numbers.    I believe   texify --pdf --texinfo="\pagenumbering{gobble}" filename.tex   should work.  It does not. No exception pops up, but the page number remains. I cannot find documentation anywhere showing examples of using the --texinfo option to splice LaTeX code into the file before running the LaTeX file to create a pdf.   How should I properly use the texify command?  Or is there another way to splice in  \pagenumbering{gobble} before running texify?


I'm thinking about proving $f(x) = (a^x+b^x)^{1/x}$ has negative derivative for all positive $x$. $$f'(x) = \left(b^x+a^x\right)^\frac{1}{x}\left(\frac{b^x\ln\left(b\right)+a^x\ln\left(a\right)}{\left(b^x+a^x\right)x}-\frac{\ln\left(b^x+a^x\right)}{x^2}\right)$$ To prove this is negative, I need $$x(a^x\ln(a)+b^x\ln(b)) < (a^x+b^x)\ln(a^x+b^x)$$ which is equivalent to $${a^x}^{a^x}{b^x}^{b^x} < (a^x+b^x)^{a^x+b^x}$$ This looks like a special case of $$A^AB^B < (A^A+B^B)^{A^A+B^B}$$ for any $A,B>0$. I'm convinced this is true, but I don't know how to prove it either.


I recently upgraded my OS to Ubuntu 20.10. I tried to ascertain if Livepatch was still running. However, when I open a terminal, it's a black screen. I can't type or paste code.  Has anyone else had this issue?


I want to buy Skyrim before the Christmas sale ends but the steam store keeps saying: Error Code: -118  Unable to connect to server. Server may be offline or you may not be connected to the internet.  Can someone help me I want to play Skyrim!!!!!????


Existence of limits and colimits in a pointed category.

I am reading Mark Hovey's model category theory. In the first chapter, on page $4$, we have a category $\mathcal C$ which has all small limits and colimits. He claims that the pointed category ${\mathcal C}_*$ has arbitrary limits and colimits. He says:  Indeed, if $F : I \to {\mathcal C}_∗$ is a functor from a small category $I$ to ${\mathcal C}_∗$, the limit of $F$ as a functor to $\mathcal{C}$ is naturally an element of $\mathcal C_∗$ and is the limit there.  I am not able to follow the argument. How did he think of $F$ as a functor to $C$? Did he forget the base point?


Does $S^1 \times S^3$ admit a complex structure?   It is parallelizable, so it admits an almost complex structure...is there a nice way to see that this is or is not integrable?


I recently watched a  that used two images simultaneously for front and side views. The images don't disappear when the speaker moves around the 3d-viewport. It's a little difficult for me to explain it in words, please watch the video to look at the image orientation.  I would love to know how that kind of image reference would be possible, because when I load any images they're only visible in one view and disappear when I switch the view.  Please let me know if any more information is required.


Quadratic Recurrence : $f(n) = f(n-1) + f(n-2) + f(n-1) f(n-2)$ Solution? How?

I have encountered this question in a coding competition and want the formula for $f(n)$. Is there any way to do this?


Neural network weights explode in linear unit

I am currently implementing a simple neural network and the backprop algorithm in Python with numpy. I have already tested my backprop method using central differences and the resulting gradient is equal.  However, the network fails to approximate a simple sine curve. The network has one hidden layer (100 neurons) with $\tanh$ activation functions and a output layer with a linear activation function. Each unit also has a bias input. The training is done by simple gradient descent with a learning rate of 0.2.  The problem arises from the gradient, which gets larger with every epoch, but I don't know why. Further, the problem is unchanged if I decrease the learning rate.  EDIT: I have uploaded the code to pastebin:


Who is the mother of the son of Godzilla from the 1967 movie of the same name?

This is the son of Godzilla () as seen in the 1967 movie .    So, Godzilla’s son is “born” after hatching from an egg a trio of giant praying mantises dig up on . Godzilla takes on the role of father to this kid, but it’s not clear who the mother of this bundle of joy is or how the egg ended up on the island to begin with.  Is there any canonical reference in the Godzilla universe that clearly states who the mother of Minya/Minilla is?  FWIW, the film  was never officially released in theaters in outside of Japan until streaming services started to carry the original Japanese film with translated subtitles.


Mental arithmetic in Mixture and allegation

A vessel is filled with the liquid,3 parts of which are water and 5 parts syrup,How much of the mixture must be drawn off and replaced with the water ,so that mixture may be half water and half syrup  I have tried:  Totally it contains 8 parts,  3/8       5/8    1/2   1/8        1/8  Ratio is 1:1,for the mixture to become half,what i am doing mistake,is anyone guide me for the Answer,But the answer is 1/5  what i am doing wrong ?


How to increase space between bibliography without using biblatex

Is there a way to increase space between bibliography without using biblatex?


Can the word 'child' be pluralised : 'childs two, three and four'?

The question  produced answers which agreed that it could not.  However, I notice today that, in Court, children, who had been named for the sake of anonymity as 'child two', 'child three' and 'child four', had been collectively referred to as 'childs two, three and four'.     Earlier in the inquest, the court heard Shukri had gone down to the river after school with Child One and three others — known as Childs Two, Three and Four.     This appears to me to be perfectly correct.  Are the Court, the newspaper report and myself all wrong in thinking that this is a 'standard English' way of properly referring to the children in question ?


Gravity in other than 3 spatial dimensions and stable orbits

I have heard from  that stable orbits (ones that require a large amount of force to push it significantly out of it's elliptical path) can only exist in a three spatial dimensions because gravity would operate differently in a two or four dimensional space. Why is this?


I'm trying to compute the symmetry plane of a 3D mesh representing an animal footprint in R.  I've ran a PCA on the 5755 points that are making up the 3D mesh (see below):  The output of the PCA is the following matrix of variable loadings (i.e., a matrix whose columns contain the eigenvectors):  The question is how can I now link these Principal Components to the symmetry plan (𝑎𝑥+𝑏𝑦+𝑐𝑧=𝑑) that passes thought the centre of mass of the 3D mesh (i.e. mean x, mean y and mean z)? I've read many times the following post but unfortunately I couldn't find a solution to my problem:  Here is my script (so far): library(Rvcg) library(rgl)  path_ply <- "/Volumes/eTrack/eTrack - Segmented 3D models"  filelist_ply1 <- list.files(path_ply, pattern = ".ply",full.names = TRUE)  i=1  filelist_ply1[i]  #Read 3D mesh (.ply) Specimen <- vcgPlyRead(filelist_ply1[i], updateNormals = TRUE,  clean = TRUE)  #Remove unwanted components Specimen <- vcgIsolated( Specimen, facenum = NULL, diameter = NULL, split = FALSE, keep = 1, silent = FALSE)  X <- t(Specimen$vb[1:3,])  #Demeaning the variables mean_vec <- colMeans(X)  X_demeaned <- matrix(NA, ncol = 3, nrow = length(X[,1])) X_demeaned[, 1] <- X[, 1]-mean_vec[1] X_demeaned[, 2] <- X[, 2]-mean_vec[2] X_demeaned[, 3] <- X[, 3]-mean_vec[3]  cov.X=cov(X_demeaned) eigen_vectors <- eigen((cov.X))$vectors eigen_values  <- eigen((cov.X))$values eigen_vectors eigen_values  a <- eigen_vectors[1, 3] b <- eigen_vectors[2, 3] c <- eigen_vectors[3, 3] d <- a * mean_vec[1] + b * mean_vec[2] + c * mean_vec[3]  open3d() plot3d(X[, 1], X[, 2], X[, 3], type = "p", col = "red", size = 1) rgl.planes(a, b, c, d, alpha=0.2, color = "#D95F02")


What's the cmd/PowerShell equivalent of back tick on Bash?

Redirecting command output:  For example:  echo "Foo `./print_5_As.rb`"   would echo "Foo AAAAA"


How is canonical correlation analysis related to multivariate regression?

Given a $m\times p$ matrix $Y$ on the left, and a $m\times q$ matrix $X$ on the right, CCA tries to find 2 sets of mapping coefficients such that $Y\beta_{l}$ and $X\beta_{r}$ have the highest possible correlation.  This resembles a multi-target regression problem that is trying to minimize the norm of $Y-X\cdot [\beta_{1},\beta_{2},...,\beta_{p}]$.  So, my question is, what's the relationship between canonical correlation analysis and multi-target (multivariate) regression?   Can anyone give any insight here? if possible, from an application perspective?


Complex numbers contain imaginary numbers as we all know but often it is used for solving real life practical problems such as taking the impedance of a capacitor, inductor etc.  Even in Signals and systems we use complex form of Fourier series,in AC circuit analysis we use complex numbers and i guess there are still more applications to come in my coming semesters.  How an imaginary number in real life can have a practical significance?  So what really makes complex numbers such a powerful tool in electronics?  In layman's term why do we use it?How does it helps us?


Javascript - How to check if current time is between two different times

I am trying programmatically check if the current time for my web application is between two predefined times. I don't know how to get the current time and then set variables that store two predefined times. The pseudo code would look like this  if(currentTime < shiftStart && currentTime <shiftEnd) {    shift = 2 }   But how do I declare and setup the variables so the code works correctly.


It is an interesting task to try finding the limit of nested square root expressions.      $$\lim_{n \to \infty}\left( 1 + \sqrt{2 + \sqrt{3+ ... + \sqrt {n + \sqrt{n+1}}}}\right)$$   How to solve this one?


Big discrepancy in number of known pages in Google Search Console and ScreamingFrog

In a technical SEO audit I used both Google Search Console and ScreamingFrog crawl to review the status errors, however there is big discrepancy in the number of pages that Google knows about, and the ones that ScreamingFrog finds (without any limitations or change in settings of the Spider).   I have 350 overall pages in ScreamingFrog and 7.2K pages in GSC. Same for the different status errors, and there is mismatch on which tool finds what. For example, GSC finds 16 404s but they are totally different pages from the 404s ScreamigFrog finds (just one overlapped).   Did you experience the same?


WiX installer problem adding registry keys

I want to add some registry using WiX installer. Here's my code:  <DirectoryRef Id="TARGETDIR">   <Component Id="DisableWeakCipherSuites" Guid="7DBE2D50-3C00-4CEF-86CC-897C0C96E7FF" KeyPath="yes">     <RegistryKey Key="SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers\RC4 40/128" Root="HKLM" Action="createAndRemoveOnUninstall">       <RegistryValue Name="Enabled" Value="0" Type="integer" />     </RegistryKey>     <RegistryKey Key="SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers\Triple DES 168" Root="HKLM" Action="createAndRemoveOnUninstall">       <RegistryValue Name="Enabled" Value="0" Type="integer" />     </RegistryKey>     <RegistryKey Key="SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers\RC4 128/128" Root="HKLM" Action="createAndRemoveOnUninstall">       <RegistryValue Name="Enabled" Value="0" Type="integer" />     </RegistryKey>     <RegistryKey Key="SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers\RC4 56/128" Root="HKLM" Action="createAndRemoveOnUninstall">       <RegistryValue Name="Enabled" Value="0" Type="integer" />     </RegistryKey>   </Component> </DirectoryRef>   But instead of adding these keys into CurrentControlSet, installer adds those keys into ControlSet001.


Disable scientific notation for Y-axis and data in pgfplots?

I've been trying to figure out how to change the chart from scientific notation to just show the 5 digit numbers. I've tried scale and scale ticks with not success.  How can I change the y-axis and data values to show the decimals not in scientific notation?  \begin{tikzpicture} \centering \begin{axis}[     width=300pt,     height=250pt,     axis lines*=left, % Don't display the top and right lines     ybar, % Display it as a bargraph     enlarge y limits={upper,value=0.2},     legend style={at={(0.5,-0.20)}, % -.20 y-axis     anchor=north,legend columns=-1},     ylabel={Densities},     nodes near coords,     every node near coord/.append style={ anchor=mid west, rotate=90},     symbolic x coords={Class1,Class3,Class5,Class7,Class9,Class11,Class13,Class15,Class17,Class19,Class21,Class23},     xtick=data,     xticklabel style={ inner sep=0pt, anchor=north east, rotate=70 },     nodes near coords align={vertical}, ] \addplot coordinates { (Class1,0.0968) (Class3,0.0887) (Class5,0.1452) (Class7,0.0726)     (Class9,0.0403) (Class11,0.0081) (Class13,0.0161) (Class15,0.0000)     (Class17,0.0161) (Class19,0.0081) (Class21,0.0000) (Class23,0.0081) }; \end{axis} \end{tikzpicture}


Assuming that $e<y<x$, prove that $ x^y < y^x$.  I think this must be easy, but I can't work it out. Thanks in advance for any kind of help.


Should I close my BestBuy Credit Card? Will it affect my credit score and history?

I was young and stupid and opened up a Best Buy credit card 5 years ago. I bought a new laptop and also a lot more stuff during these 5 years. I have bought over 10,000 dollars worth of stuff and paid it all off today. The interest rate on the card is 24.something percent.   Due to personal financial reasons, I was not able to take advantage of low rate offers from Best Buy on stuff I bought on the card and ended up paying a whole bunch of money as interest.   I want to close this credit card for several reasons:   It doesn't have a Mastercard/Visa/etc logo on it so I can only use it at Best Buy. The interest rate is ridiculously high. I spend more money because I get enticed into offers that come with this card. But I do not want to spend any more money than I can afford. I will have to pay annual maintenance fee even if I don't use this card.   My question is, if I close this card which has a 4000 dollar credit limit on it, will it affect my credit score or credit history? Does it make sense for me to keep it open or just close it permanently? Will my total credit limit go down as a result as this card is not offered by a major credit card provider?


Nearest distance between point and line layers in QGIS

I have two layers, a line and a point layer.  I need to make a line layer which connects all the points to the nearest line feature. How can I do that?  Is there a plugin available for QGIS? This is a very important tool which is missing in QGIS.  ArcView has this tool:


Scared of damaging bike going up and off curbs

Bike: Giant ATX 27.5 2 (2016) - Hardtail  My current strategy to going off curbs is nose diving... I know, the best.  My current strategy to going up curbs is barely lifting my front wheel onto the curb and than just letting the back wheel smash into the curb hoping it rolls onto it... once again, not the best.  I'm scared of seriously damaging the bike (specifically tires/rims) when I go off curbs.  Could anyone recommend be strategy's to going up and down curbs (and similar obstacles: fallen trees, rocks etc)?  And also, is there any way to find out how much PSI is currently in a tire, and what PSI should a mountain bike tire be at?


LinkedList have static class named as Entry.Why it is static and what would be the benefits ?

Linklist have static class named as ENTRY  private static class Entry<E> { E element; Entry<E> next; Entry<E> previous;  Entry(E paramE, Entry<E> paramEntry1, Entry<E> paramEntry2){   this.element = paramE;   this.next = paramEntry1;   this.previous = paramEntry2; } }   And an object has created inside LinkList  private transient Entry<E> header = new Entry(null, null, null);   Following are my questions?   Why it is static ? If we define more than two LinkList will it share the same static class 'Entry'?


Prove that a certain ideal $I$ of $\mathbb Z [x]$ is not a principal ideal.

It is a homework question which wants us to prove that  $I=(x,2)=\{h(x)=xf(x)+2g(x):f,g\in\mathbb Z[x]\}$ is not a principal ideal.  I thought of trying to make a contradiction but I have no idea where to start with.  Could anyone help me with this please?


What should I write if I mean the time before and after 1900 (summa summarum about 30 years). I am not a native speaker that's why I am not able to decide which expression is right. My ideas are: - at/around the turn of the 19th to the 20th century - at/around the turn of the 19th - 20th century - at/around the turn of the 20th century Thank you in advance for your help!


How to create a "succeeds or precedes" symbol?

Might be an obvious (or impossible) request, but does anyone know if there's an equivalent of the "less than or greater than" symbol but for "succeeds or precedes?" Thanks!  I've tried using detexify (which would just come back with the \lessgtr symbol) and looking through as many of the math symbol pdf guides as I can find. I might just be missing it, but I've tried searching a few different ways. Alternatively, if the sumbol doesn't exist, is there an easy (and at least somewhat elegant) way to force a \succ and \prec on top of each other?


How to automatically insert a new received email into a specific Gmail label?

On my Gmail account I have create a new label named: Work, now I want that when I receive a new email from some specific address (for example: myboss@example.com) these messages are automatically inserted into the Work label.  Can I do this operation? What have I to do?


WSL2 in Windows 10: sudo: /etc/sudoers is owned by uid 1000, should be 0

I don't exactly know what I did wrong, but now every command that needs sudo returns: sudo: /etc/sudoers is owned by uid 1000, should be 0 sudo: no valid sudoers sources found, quitting sudo: unable to initialize policy plugin  I found a bunch of answers for fixing this in these situations:  If I was running Linux and could boot with a live USB If I was running Mac OSx.  But I'm running WSL2 in Windows 10, so these answers didn't helped me. Have I rendered my WSL useless? Is there a way to fix this windows-side? Things I've tried in WSL terminal (Ubuntu 20): pkexec chown root:root /etc/sudoers /etc/sudoers.d -R pkexec visudo  Both gives me Error getting authority: Error initializing authority: Could not connect: No such file or directory response. I've also tried su - root, but I put my password and it gives me Authentication failure. Let's suppose this has no answer and I need to reset my Ubuntu WLS install. Is there a way to export everything that I did, installed and all, or will I have to start ALL over? Thanks a lot.


How to do power analysis for Fisher exact test in tables larger than 2x2?

I have 4x2 contingency tables and would like to perform Fisher's exact test on them. R stats package() supports 4x2 test by combing p-values with Monte Carlo simulation. The result is not significant. I would like to perform power analysis to check whether the sample size is too small to detect differences between two categorical variables. However, R stats package () does not support the analysis on 4X2 tables. Do you know how to perform power analysis in this case? Is there any implementation supporting it?  Many thanks!


Did the wizarding world interfere with the muggle world?

Another question that bothers me: when muggles had big problems and wars going on, did the wizarding world interfere?  Did they help or interfere with the muggles in the world war or even in wars earlier than that? Against Napoleon or in the war against the Roman Empire? Couldn't they prevent the wars and battles?


Got a new iPhone - where am I supposed to receive the verification code?

I just got a new iPhone to replace my broken one. I can't really do much without signing into iCloud, which requires me to use a verification code. This can either be sent to some other trusted apple device of mine (no such device exists), or as a text to my phone (that won't work because I'm trying to set up my phone). So how can I sign in to iCloud?


I'm looking for command line code to show the window below AND execute the link "Nach Updates suchen" (looking for updates). By wuapp.exe only the window is shown.


Upgrading from a smaller hard drive to a larger one on a dual boot system

So I have Ubuntu and Windows 7 on a 500GB hard drive setup for dual boot. Recently some of the sectors on the Windows 7 partition of the drive went bad. I want to upgrade the hard drive I have now to a 2TB one and also get rid of the sector issue at the same time.   What would be the best (and safest) way to go about transferring the whole system to a new, larger hard drive?


Local translations included in covariant general coordinate transformation

It is known that if we use the constraint $R_{\mu\nu}(P^{a})=0$ , i.e. the curvature of local translations vanishes, then we can modify general coordinate transformations (gct) to a covariant generalisation thereof (cgct) in such a way that these cgct include local translations. Rephrasing this, local translations can be thought of covariant diffeos.  If   a. LOCAL Lorentz covariance corresponds to the statement that there is no preferred inertial reference frame on curved space.  b. GLOBAL translation invariance corresponds to the statement that a NON-GRAVITATIONAL theory does not distinguish different points in spacetime, and  c. diffeomorphism invariance corresponds to the statement that the coordinate system chosen does not matter  THEN my questions are   Is it safe to assume that LOCAL translation invariance is just the curved space generalisation of the GLOBAL translation case, such that they still correspond to not having a preferred origin, but in curved manifold parlance? Or do they mean something completely different? What does it mean to say that LOCAL translations are eaten up by covariant gct? I assume that the theory is still invariant under them, in the sense that there is no preferred origin. But somehow now this statement comes from diffeos?   In a way I have always been confused about this, as I fail to clearly see the difference between diffeo invariance and the "no preferred reference frame" of local Lorentz. Now I am even more confused because diffeo invariance seem to contain both 'no preferred origin' and "no preferred reference frame".  Notation:  $R_{\mu\nu}(P^{a})=\partial_{[\mu}e_{\nu]}^{a}+2\omega_{[\mu}^{ab}e_{\nu]b}-\frac{1}{2}\overline{\psi}_{\mu}\gamma^{a}\psi_{\nu}$  $P^{a}$ is the generator of local translations.  References:   D.Z. Freedman & A. Van Proeyen, SUGRA, 2012; p. 225


Can credit card be used as a debit card by making payments into credit card before even using it?

I am planning to use Halifax clarity credit card abroad when I travel to Europe. The credit card offers good rates while using abroad with no transaction charge or non sterling transaction charge (only interest charges apply). If I use my debit card abroad there are host of charges which come into the picture.  My question is can I make payments into my credit card from my debit card bank account without even using it and then use that money for credit card transactions? This means if my credit card balance is nil (not used even once for any transaction) and I pay suppose £500 from by bank account into credit card - can I use the paid amount through my credit card transactions in the future?  My assumption here is that I won't pay interest charges unless I start using my actual credit card limit. Am I right in understanding this or am I missing something?


I'll be straightforward. What do you call a test for someone who missed the actual test date/schedule? For example, one should have taken the test last Monday, but he missed it. Then he got another chance to take the test on Wednesday. Let's pray he doesn't miss that one. What do you call that test on Wednesday? I tried googling and the closest I can find was "late test". Any ideas would be helpful. Thanks.


Dual boot. How do I reinstall the Ubuntu partition?

I just got a new netbook and I'm setting up operating system configuration. It came with windows 7 starter but I installed dual boot Ubuntu 12.10. I've been writing on some forums and now I don't want things from previous searches and stuff popping up in public so I'm considering a disc wipe and reinstallation of Ubuntu.  Ubuntu was installed by downloading an iso from inside Windows, then put on an usb drive and rebooted and installed alongside windows. I did not do any fancy configuration about swap spaces or partitions. When I start, I get to choose if I want to boot up as Windows or Ubuntu. It automatically chooses Ubuntu. Also, I would like to change this so that it chooses Windows by default.  My question is, is it possible to reinstall Ubuntu without having to reinstall Windows 7?  I'm not interested in a wiping of free disc space or any goverment-level confidentiality. I just want my Ubuntu partition cleared, from occasionaly peeping curious eyes, not having previously visited websites or previously written documents popping up accidentally. If I remove Ubuntu from my hard drive, and then install it again, will a lot of the stuff still be there? I really would like not to format my hard drive because I have stuff on the windows part of the system that I use.


use contradiction to prove that the square root of $p$ is irrational

On a practice exam, our teacher provides us with this question and this answer.     Let $p$ be a prime number. Use contradiction to prove that $\sqrt{p}$ is irrational.   ANSWER: By way of contradiction, assume $\sqrt{p}$ is rational. Then there exist $a, b \in \mathbb{Z}$ with $b\neq 0$ such that $\sqrt{p} = \frac{a}{b}$. Without loss of generality, we may assume $\text{gcd}(a,b) = 1$. Then $p = \frac{a^2}{b^2}$. Thus $p | a^2$ which implies $p | a$, i.e., $\exists k \in \mathbb{Z}$ such that $p k = a$. We now have $p b^2 = (\pi k)^2 = p(p k^2)$, so $p b^2 = a^2$. Since $p \neq 0$, $b^2 = p k^2$, which means $p|b$. Thus $p$ is a common factor of $a$ and $b$. This is a contradiction as $a$ and $b$ are relatively prime.  My question is, how do you know to assume that the $\text{gcd} (a,b)=1$? It seems really random and I don't know why the proof jumps there.


Exactly which users PII do moderators have access to?

here on meta has brought to my attention something I never realized before - non-employee moderators have access to some tools that can disclose an user EMail address.  Since I was quite surprised by this discovery (yes, I know, it has probably been referenced before but I didn't know, sorry) I had the idea to look at the Privacy Policy to see what other data can non-employee access.  I wasn't able to find any definitive info, only this relevant passage:     We collect information such as your username, password, email address, IP address (collected at each site visit). This information is also used to identify individual users to the public Network and to award activities and attribute them to you. Your username and additional content you provide including your profile picture, question and answer content, and your reputation are visible publicly. Other limited information is visible to moderators, who have elevated access privileges, and may access content including your posts. For more information about moderators and their role in the Stack Overflow Network, please visit: /help/site-moderators.   Sadly, this doesn't seem to further elaborate what other "limited information" is visible to moderators.  I am therefore asking for support here: is there a page that list which users PII non-employee are granted access to? Or can anyone give me some info in that regard?


When should you use "to" following a "why"?

I've always wondered why some people add a to after Why when framing a question. I have always wished to know this, but I keep forgetting to ask and today I came across a tweet that made me post this question here. The sentence that I came across on my twitter feed is:  Why To Treat Your Product Like It's Finished?   Isn't it more appropriate to ask:  Why Treat Your Product Like It's Finished?   I know that all the words in the sentence above have a capital letter in front because this was a title of a post. But that is not the point.  My question is: When do we need to use a preposition like to after a question word like Why? Are there any grammatical rules regarding this usage? If so, what are they?  Why To Treat Your Product Like It's Finished (Even Before It Is) — Buffer (@buffer)


I've been using PB for quite a while now, but, Thrift has constantly been at the back of my mind.  The primary advantages of thrift, as I see it are:   Native collections (i.e, vector, set etc) vs PBs repeated providing functionality similar to, but not quite like (no iterators unless you dig into RepeatedField which the documentation states "shouldn't be required in most cases"). A decent RPC implementation provided, instead of just hooks to plug your own in. More officially supported languages (PB offers "official" support for Java, C++, Python)   The cons of Thrift:   The RPC implementation means I can't plug in my own (for example) encryption/authentication layer on top. Windows support doesn't seem to be great. PB definitely seems to have, if not better, more accessible documentation.   Neutral:   Unknown size of .lib/.dll on Windows (Thrift). Large size of .lib on Windows (PB, but it does offer a -lite which is significantly smaller). Speed wise, they both seem to be similar.   I'm not quite ready to take the plunge and switch to Thrift yet, can anyone offer me more pros/cons, or reasons to go one way or the other?  Thanks!


I'm trying to see how many times foo bar appears in /var/log/foo.log within an arbitrary amount of time on a remote server, but nothing that I've tried so far has worked.  I've already got a timer script that I use to keep track of how long it has been since I started tailing /var/log/foo.log, and now I'd just like a way to tell how many times foo bar has appeared in the tailed output.  I searched google, but I didn't find anything pertinent within the first 10 pages of results.    Here's what I've tried with frustrating results:  ## works on local machine, but doesn't work as expected on remote tail -f /var/log/foo.log | grep foo\ bar | sed '='  ## works on local, but not remote tail -f /var/log/foo.log | grep foo\ bar | cat -n -  ##  works on local, but not remote tail -f /var/log/foo.log | grep foo\ bar | awk -F'\n' '{printf "[%d]> ", NR; print $1}'   I even tried to write a sed script that'd act like tail -f, but I made limited-to-no headway with that.  NOTE  the remote server is running an older version of coreutils, and upgrading is an option, but is NOT in any way the desired solution.


I don't want Google to show sub domain name (red circles in the below image) in search results. How to prevent Google from showing sub domain name as title in search result?


Find all homomorphisms of the ring $ \mathbb{Z_6} $ in $ \mathbb{Z_{15}} $ (verification).

So this is what I did Will be homomorphism if and only if the two conditions are satisfied. n= 6 m= 15 a ={1, 2, ...., 15} i) an $\equiv$ 0 (mod m) ii) a $\equiv$ $a^2$ (mod m) The only two number that satisfies both conditions are 0 and 5. I also use the formula ( $2^{w(l)-w(\frac{1}{(l,k)})}$ where l=15,k=6) to know how many numbers are homeomorphism and also got two. Is this correct?


How to delete visible Desktop.ini, Thumbs.db and album art from My Music

How do I delete album art, desktop.ini, and thumbs.db from my music folder in Windows 7? I can see all of these files because I took the hard drive from my old computer and put it in my new one. It now has all of these junk files that the OS does not use, so I want to delete them and get them out of my sight.


Show that any continuous $f:[0,1] \rightarrow [0,1]$ has a fixed point $\zeta$

Be a continuous function $f:[0,1] \rightarrow [0,1]$.  Show that there is a $\zeta \in [0,1]$ with $f(\zeta)=\zeta$ ($\zeta$ is called fixed point).  Consider the function $g:[0,1] \rightarrow [-1,1]$, $g(x):= f(x)-x$.  $g$ is continuous.  Because of $f(0),f(1) \in [0,1]$ is $g(0)\geq0$ and $g(1)\leq 0$.   Because $f(0)$ has a value between $0$ and $1$, $f(0)\geq 0$.  $g(0) = f(0)-0= f(0) \geq 0 - 0 = 0$.  Because $f(1)$ has a value between $0$ and $1$, $ f(1) \leq 1 $.  $g(1)=f(1)-1 \leq 1 - 1 = 0$ $\Leftrightarrow g(0)\geq 0$ and $g(1)\leq 0 $  After the IVT: $\exists \zeta \in [0,1]:g(\zeta)=0 \Leftrightarrow f(\zeta) = \zeta $  $\zeta$ is a fixed point of $f$. $\Box$  My questions are:  Is this proof done in the correct way or have I missed something?  Is there something I can improve?


Showing that $\nabla\times(\nabla\times\vec{A}) = \nabla(\nabla\cdot\vec{A})-\Delta\vec{A}$

I have faced difficulties while trying to prove that  $$\nabla\times(\nabla\times\vec{A}) = \nabla(\nabla\cdot\vec{A})-\Delta\vec{A}$$   I don't have any clue how can I start to work with it. Any hint will be helpful.


Find path of standard executable for a given file type in Windows

Suppose I am running cmd and I open an application by typing for example start document.pdf  I want to get the exact path of the executable that opens .pdf files  Of course I could search the entire system for the executable but I suppose it would be faster this way because the path is already stored somewhere  I don't know if it makes a difference but I am using Windows 7


Bayesian vs frequentist Interpretations of Probability

Can someone give a good rundown of the differences between the Bayesian and the frequentist approach to probability?  From what I understand:  The frequentists view is that the data is a repeatable random sample (random variable) with a specific frequency/probability (which is defined as the relative frequency of an event as the number of trials approaches infinity). The underlying parameters and probabilities remain constant during this repeatable process and that the variation is due to variability in $X_n$ and not the probability distribution (which is fixed for a certain event/process).  The bayesian view is that the data is fixed while the frequency/probability for a certain event can change meaning that the parameters of the distribution changes. In effect, the data that you get changes the prior distribution of a parameter which gets updated for each set of data.  To me it seems that the frequentist approach is more practical/logical since it seems reasonable that events have a specific probability and that the variation is in our sampling.  Furthermore, most data analysis from studies is usually done using the frequentist approach (i.e. confidence intervals, hypothesis testing with p-values etc) since it is easily understandable.  I was just wondering whether anyone could give me a quick summary of their interpretation of bayesian vs frequentist approach including bayesian statistical equivalents of the frequentist p-value and confidence interval. In addition, specific examples of where 1 method would be preferable to the other is appreciated.


SQL log shipping from different hosts on different versions

We have a current setup where we have two SQL 2008R2 database servers in production.  Our reporting team requested a single place they could query data from both servers (to avoid both hitting production directly and the performance issues with linked servers).  So we set up log shipping where we ship several databases from both sources to a target server.  It works great, the databases on the target server are read only during the day and only unavailable when the log shipping restores are scheduled at night.  However, the vendor applications for both source servers are going through an upgrade project, and they will unfortunately have to be be different versions (SQL 2014 and 2016 respectively). Most of what I have researched seems to say that you cannot log ship from a different source version, but I've also found information suggesting that you can ship from a lower to a higher version, but am unable to find anything official. So, my question is, is it possible to log ship from both 2016 and 2014 sources into a 2016 destination, AND leave the databases read only when they are not restoring?  And is there official Microsoft confirmation of this?


Why do programs in Unix-like environments have numbers after their name?

For example, when I run man ioctl the page says IOCTL(2) at the top. What does that mean? Is there an IOCTL(1)? And how does one navigate between these?


In Game of Thrones we have seen Gendry the bastard of Robert Baratheon who browed away from Dragonstone, apparently never to be seen again. Where did he go? From season 3.


I'm 15 and recently started electronics and I'm having trouble understanding voltage. I've read so many articles and watched so many videos about voltage and they all give different answers. Some of them say that voltage is like pressure, others say that voltage is is like gravitational potential energy and then some say its a measure of electric field strength. So as you can see, I don't know what to think. Could someone please explain it to me because I've been trying to find an answer for like 2 months and it's kinda driving me insane :) And also if voltage is like gravitational potential energy, how does more voltage mean more current?


Let $K$ be the subgroup $K=\{e,(1, 2)(3, 4), (1, 3)(2, 4), (1, 4)(2, 3)\}$ in $S_4$.   show that $K$ is normal in $S_4$.  show that $S_4/K \cong S_3$.    I know that I could try to prove this directly by the definition of normality, but that would be too long. I am thinking something like applying the First Isomorphism Theorem, like if I could some how make K a kernel of some surjective function. But I just don't know how to deal with functions of cycles.  Can anyone help please?  Thanks


java.util.date to java.sql.date conversion NPE

I am trying to set up a method to convert java.util.date typed variables into java.sql.date typed variables so they can be persisted to database.  However, the code I set up keeps returning a null pointer exception, even though I am getting values on the argument being passed into the method.  public static java.sql.Date convertUtilDateSQLDate(java.util.Date utilDate){          long utilDateTime = utilDate.getTime();          java.sql.Date sqlDate = new java.sql.Date(utilDateTime);          return sqlDate;      }   Does anyone know why this might be happening?


Refer to the "name" of an equation, while a List of Equations is generated using these names

I link two questions below because I use their solution, to number my equations and generate a list of my equations.   My question about numbering equations:  Generate a list of equations:    Although they might not be directly relevant, I mention I use them because I am not sure if this messes up possible solutions.  Below my MWE. This works fine so far (Figures attached).  But I want the "list name" of my equation (in this case: \myequations{PDE of the diffsion process}) to be available as a kind of variable so that I can refer to it as "The \XXX is given by", where \XXX is a command giving me the Name (\myequations{...}) of the equation I refer to (e.g., \tag{\ref{eq:litdiff}}).  I hope my equation is clear, if not, please tell.  MWE:  \documentclass[12pt]{report} \usepackage{tocloft} \usepackage{amsmath} \usepackage{physics} \usepackage[a4paper,width=150mm,top=25mm,bottom=25mm,bindingoffset=6mm]{geometry}  \newcommand{\listequationsname}{List of Equations} \newlistof{myequations}{equ}{\listequationsname} \newcommand{\myequations}[1]{% \addcontentsline{equ}{myequations}{\protect\numberline{\theequation}#1}\par} \setlength{\cftmyequationsnumwidth}{2.5em}  \newcommand{\subs}{\text{s}}  \begin{document}  \listofmyequations  \chapter{Diffsion}  The PDE of the diffsion process is given by \begin{subequations}\label{eq:litdiff} \begin{equation} \pdv{}{t} (\widetilde{c}_{\subs}(r,z,t)+c_{\subs,0})=\frac{D_{\subs}}{r^{2}}\pdv{}{r} \left(r^{2}\frac{\partial (\widetilde{c}_{\subs}(r,z,t)+c_{\subs,0})}{\partial r}\right) \tag{\ref{eq:litdiff}} \end{equation} \myequations{PDE of the diffsion process} \noindent The boundary conditions of Eq.~\eqref{eq:litdiff} are given by \begin{align} D_{\subs}\pdv{}{r} \widetilde{c}_{\subs}(0,z,t) &= 0 \label{eq:diffusionpartialdiff_boundaries0}\\ D_{\subs}\pdv{}{r} \widetilde{c}_{\subs}(R_{\subs},z,t) &= -j(z,t)\label{eq:diffusionpartialdiff_boundariesRs} \end{align} and the initial condition is given by     \begin{equation}         \widetilde{c}_{\subs}(r,z,0) = 0 \quad r\in [0;R_{\subs}].     \label{eq:diffusionpartialdiff_init}     \end{equation} \end{subequations}  \end{document}


How can I speed up rendering an animation with Cycles?

I started to render an animation (of 200 frames), using 1000 samples, at 1920x1080 pixels, of a scene including a fog object and mesh files  (from Alias). It took almost 10 hours for 1 frame, so I think that something is wrong. Is this a usual amount of render time? I want to keep the quality as high as possible. I'm using Cycles rendering with CPU, because when I try to use GPU, Blender shuts down. Specs: AMD Ryzen 5 3600- 6 core processor 16 Gb RAM GTX 1660 SUPER