i recently installed Android Studio using this method ""   something wrong happened during the installation when i open the app it gave me an error loading the virtual phone inside the application i want to fully remove android studio and REinstall it again , I tried deleting the /android-studio folder along with the hidden /.android  I have tried   sudo apt-get remove android-studio  it says failed to locate the package .   i have tried all the methods here , i don't know maybe i did something wrong or i just jumped a step i don't know ! i'm trying to learn Linux but oh my god   unstoppable problems

I installed Android studio some time ago using the following suggested method:     To set up Android Studio on Linux:      Unpack the downloaded Tar file,   android-studio-ide--linux.zip, into an appropriate location   for your applications. To launch Android Studio, navigate to the   android-studio/bin/ directory in a terminal and execute studio.sh. You   may want to add android-studio/bin/ to your PATH environmental   variable so that you can start Android Studio from any directory.   Follow the links to install the SDK outside of the Android Studio   directories.   For whatever reason it has become corrupt and insists I must un-install and re-install. I can't for the life of me find how to un-install it however.  I didn't use apt-get so I can't do apt-get remove.  Does anyone have any suggestions?


How put halo around text using the contour package as suggested  in many nodes by defining a style?  MWE:  \documentclass[tikz]{standalone}  \usepackage[outline]{contour} %halo around text %https://tex.stackexchange.com/questions/18472/tikz-halo-around-text \contourlength{1.2pt}  \usetikzlibrary{patterns}  \begin{document}      \begin{tikzpicture}[halo text node/.style={circle, draw, pattern=north east lines}]      \node [halo text node] {\contour{white}A};      \end{tikzpicture}  \end{document}   Result:    What I want is to include an option for the tikzpicture in a form similar to halo text node/.style{...,text=\contour{white}} instead of using \contour{white}{...} inside every node.

I would like to create a TikZ style that adds a thick outline to the node text using the \contour{<colour>}{<text>} macro from the contour package (as in the answer to the question ), i.e. I want to define a style halo so that  \node [halo] {Text};   is equivalent to  \node {\contour{red}{Text}};   My problem is that I cannot tell TikZ to use the node text as an argument for a macro.  The font option only works with switches like \itshape (as opposed to \textit{}, which requires the text to be italicised to be provided in the argument).  There are two keys execute at begin node={<code>} and execute at end node={<code>} that can be used to call code at the beginning and end of the node, but I can't split the \contour command up using execute at begin node={\contour{red{} and execute at end node={}} because the brackets don't match. Replacing { with \bgroup and } with \egroup fails with Missing } inserted.  Here's am MWE to play with:  \documentclass{article}  \usepackage{tikz} \usepackage[outline]{contour} \contourlength{1.2pt}   \begin{document}      \begin{tikzpicture}     \node {\contour{red}{Text}}; %    \node [font=\contour{red}{}] {Text}; % Doesn't change the text %    \node [execute at begin node={\contour{red}{},execute at end node={}}] {Text};  % Fails with ``Runaway argument?'' %    \node [execute at begin node={\contour{red}\bgroup},execute at end node={\egroup}] {Text};  % Fails with ``Missing } inserted''     \end{tikzpicture} \end{document}


I am using Python (both 2 and 3) for data analysis. When loading large data sets (eg. into a numpy array) then my whole system freezes. It does not react to anything, also not Ctr + Alt + F1. So I have to do an hard reset.  I have this problem in both Ubuntu and Debian.  Is there a way to execute a Python script "save", so that the script crashes and not the whole system?

I use my computer for scientific programming. It has a healthy 8GB of RAM and 12GB of swap space. Often, as my problems have gotten larger, I exceed all of the available RAM. Rather than crashing (which would be preferred), it seems Ubuntu starts loading everything into swap, including Unity and any open terminals. If I don't catch a run-away program in time, there is nothing I can do but wait - it takes 4-5 minutes to switch to a command prompt eg. Ctrl-Alt-F2 where I can kill the offending process.  Since my own stupidity is out of scope of this forum, how can I prevent Ubuntu from crashing via thrashing when I use up all of the available memory from a single offending program?  At-home experiment*!  Open a terminal, launch python and if you have numpy installed try this:  >>> import numpy >>> [numpy.zeros((10**4, 10**4)) for _ in xrange(50)]   * Warning: may have adverse effects, monitor the process via iotop or top to kill it in time. If not, I'll see you after your reboot.


We can say that $X (\cos \frac{\theta}{2} |0\rangle + e^{i \phi}\sin \frac{\theta}{2} |1\rangle) = \cos \frac{\pi-\theta}{2} |0\rangle + e^{-i \phi}\sin \frac{\pi-\theta}{2} |1\rangle$, a fact that can be derived by multiplying the $X$ matrix and the state vector and using angle identities: $X (\cos \frac{\theta}{2} |0\rangle + e^{i \phi}\sin \frac{\theta}{2} |1\rangle) = e^{i \phi}\sin \frac{\theta}{2} |0\rangle + \cos \frac{\theta}{2} |1\rangle = e^{i \phi}\cos \frac{\pi - \theta}{2} |0\rangle + \sin \frac{\pi - \theta}{2} |1\rangle = \cos \frac{\pi-\theta}{2} |0\rangle + e^{-i \phi}\sin \frac{\pi-\theta}{2} |1\rangle$ Is there a writeup somewhere or a standard way to derive this identity for other gates, i.e. $Y, Z, H, \sqrt{Y}$?

Suppose I have an arbitrary qiskit $U_3$ gate: $U_3(\theta,\phi,\lambda)$. Is there a way I can find which axis the gate is rotating around? In other words, given any real numbers $\theta,\phi,\lambda$, can I find the vector $\hat n = (n_x,n_y,n_z)$ that the gate corresponds to, so that I can plot the axis of rotation on the Bloch sphere? I'm thinking about the y-z decomposition, but I'm still unable to find out the elements of $\hat n$. How can I figure that out? Thanks a lot for the help:)


The Twin Paradox involves 2 observers, usually twins. Let them be named A and B. A remains at rest in the same reference frame as Earth while B is in a separate reference frame moving at velocity v, close to the speed of light, from A. After a certain amount of time, B switches reference frames to another which moves at the same speed but in the opposite direction, towards A.   Generally, we would say that due to time dilation, B would have aged less than A. However, consider the case where B is stationary and that the Earth together with A are moving similarly and changing reference frames. In this case, A would have aged less than B.  These 2 cases should both be equally valid through the observations of A and B. However, this would cause a contradiction in how they have experienced time.   Please enlighten me on how this is resolved where A ages more than B. I would like to find out if I have made any misconceptions in my understanding.

I read a lot about the classical twin paradox recently. What confuses me is that some authors claim that it can be resolved within , others say that you need . Now, what is true (and why)?


I'm currently working on a WordPress child theme and I needed a way to delete all the data on uninstall, so I found  in the WordPress documentation.  I tested uninstall.php or the register_uninstall_hook but it doesn't work when the theme is uninstalled.  Here's my uninstall code:  function uninstallMe() {     if ( ! defined( 'WP_UNINSTALL_PLUGIN' ) ) {         die('Heey dude, wanna coffee?');     }     global $wpdb;      $sql = "DROP TABLE IF EXISTS {$wpdb->prefix}coffee_tags";     $wpdb->query($sql);      exec("crontab -l | grep -v 'mycustomcron0047.php' | crontab -");      $sysPath = dirname($_SERVER['DOCUMENT_ROOT']) ;     unlink($sysPath.DIRECTORY_SEPARATOR.'config.php');     unlink($sysPath.DIRECTORY_SEPARATOR.'mycustomcron0047.php'); } register_uninstall_hook( __FILE__, 'uninstallMe' );   Is there an alternative way to remove data on child theme uninstall? Or a way to make default ways work?

Is it possible to perform an action only if the theme is deleted (not deactivated) from the theme directory ?  For example, I want to remove the theme settings from database after the theme is removed. So I want to run this when the theme is deleted:  delete_option( 'mysettings' );


I have found variations on this, but not this specific one. I have had a local account on my laptop for some time, which has just been joined to the company domain. I am a local admin, but not a domain admin. I'd like to copy my local profile into the domain profile. (Not hack up the registry to point both accounts to the same directory)  Windows Easy Transfer requires me to be a domain admin. The 'registry profile list' method on Technet leaves you with one profile essentially, and also doesn't work for me (can't open ntuser.dat for the local profile). Is there another way, or a tool to do this?

I have a local user on my laptop. My company is migrating to a domain setup and I want to migrate the local user to a domain user, with all the settings (desktop, Start menu, programs) intact. How can I do that?  Also, is it possible to have a local user with the same settings as the domain, for when I'm working on my laptop while not connected to the domain?


I am not sure how to use using statement correct. I try like this: [HttpDelete("{ClubId}", Name = "DeleteOpenings_Club")] public async Task<IActionResult> DeleteClub_IsOpening([FromRoute] string ClubId) {         using (_db_ClubIsOpen)         {             var result = _db_ClubIsOpen.ClubIsOpen_TBL.Where(x => x.FK_Club == ClubId);              foreach (var item in result)             {                 _db_ClubIsOpen.ClubIsOpen_TBL.Remove(item);             }              _db_ClubIsOpen.SaveChanges();              return Ok();         } }

User  answered the wonderful  question by mentioning the using keyword. Can you elaborate on that? What are the uses of using?


Consider $$\lim_{(x,y)\to(0,0)} \frac{xy}{|x|+|y|}$$  I tried the following technique but couldn't work it out   define $p=(x,y)$ we end up with the following inequalities :  $$|p|^2=x^2+y^2\\ |x|≤|p| \\ |y|≤ |p|$$  But couldn't use them at all couldn't find a boundary. What should I do? What would you recommend?

I have this function:  $$ f(x,y) = \frac {xy}{|x|+|y|} $$  And I want to evaluate it's limit when $$ (x,y) \to (0,0)$$ My guess is that it tends to zero. So, by definition, if:  $$ \forall \varepsilon \gt 0, \exists \delta \gt 0 \diagup \\ 0\lt||(x,y)||\lt \delta , \left|\frac{xy}{|x|+|y|}\right| \lt \varepsilon $$ Then $$ \lim_{(x,y)\to(0,0)}\frac {xy}{|x|+|y|} = 0 $$ So:  $$ \left|\frac{xy}{|x|+|y|}\right| = \frac{|xy|}{|x|+|y|} = \frac{|x||y|}{|x|+|y|} \le 1 |y| \lt \delta $$  So for any $$\delta \lt \varepsilon$$ the inequality is true. Hence, the limit exists and is equal to zero.  . Am I wrong or is Wolfram|Alpha wrong?


Is it possible to concat two regex variables in Ruby?  r1 = /my_str/ r2 = /my_str1/ r3 = r1+r2   Can anyone give any suggestions?

Is it possible to do something like this?  var pattern = /some regex segment/ + /* comment here */     /another segment/;   Or do I have to use new RegExp() syntax and concatenate a string? I'd prefer to use the literal as the code is both more self-evident and concise.


Problem:     Prove that $\lfloor 2x \rfloor + \lfloor 2y \rfloor \geq \lfloor x \rfloor + \lfloor y \rfloor + \lfloor x+y \rfloor$ for all real $x$ and $y$.   I have my proof down below. Its a little complicated though. This is not a duplicate of the same question on another page on math.stackexchange.com because I provide my answer.

Prove that $\lfloor 2x \rfloor + \lfloor 2y \rfloor \geq \lfloor x \rfloor + \lfloor y \rfloor + \lfloor x+y \rfloor$ for all real $x$ and $y$.  How should I solve this?  I can't think of a way with casework and I can't really simplify it more.  Thanks in advance for posting a proof!


Is  the following statement is True/false ?  For $x∈\mathbb{R}^n$ , let $B(x,r)$ denote the closed ball in $\mathbb{R}^n$(with Euclidean norm) of radius $r$ centered at $x$. Write $B=B(0,1)$.If $f,g:B→\mathbb{R}^n$ are continuous functions such that $f(x)≠g(x)$ for all $ x∈ B$, then   There exist $ϵ>0$ such that $ B(f(x), ϵ) ∩ B(g(x), ϵ)=\varnothing$  for all $ x∈ B$  My attempt :  i take  $f(x) = x$, $g(x) = x+1$, now  i visualize the diagram  i take $ϵ$ as constant  that greater then $0$  from  the diagram  i can conclude that this statement is false .  Is  its  True ?  any hints/solution will be appreciated  thanks u

For $x∈\mathbb{R}^n$ , let $B(x,r)$ denote the closed ball in $\mathbb{R}^n$(with Euclidean norm) of radius $r$ centered at $x$. Write $B=B(0,1)$.If $f,g:B→\mathbb{R}^n$ are continuous functions such that $f(x)≠g(x)$ for all $ x∈ B$, then which of the followings are true?       $f(B)∩g(B)=\varnothing$  There exist $ϵ>0$ such that $||f(x)-g(x)||> ϵ$ for all $ x∈ B$  There exist $ϵ>0$ such that $ B(f(x), ϵ) ∩ B(g(x), ϵ)=\varnothing$ for all $ x∈ B$ ${\rm int }(f(B)) ∩ {\rm int }(g(B))=\varnothing$ , where ${\rm int}(E)$ denotes the  interior of a set $E$      How can I solve this problem? Can anyone help?


Say the set $A$ is countable, therefore we can write $A = \{x_0,x_1,x_2,......\}$ $\subseteq \mathbb{R}^2$. But, we can also write, $A = \bigcup \{x_i\} $. And we know a single point in $\mathbb{R}^2$ is a closed, therefore $A$ is closed since it is a countable union. Is this true?

There is a theorem that states that the finite union of closed sets is closed but I was wondering if we have a set that consists of countable many subsets that are all closed if that set is closed. I really want to believe that the set is closed but I've been wrong in past so if anyone can supply me with an answer I would be very grateful.  Thank you.


I recently came across a program called TikZ, for creating graphics. I don't know how to install it! In its website I didn't see any instructions. Could any one help me? I am using Windows 7 Home edition. Thanks

TikZ is undergoing lots of development with new features being added, but the versions distributed with standard TeX releases are often a little old. How do I get the latest version? If I want to be sure that I get the latest stable version, how do I do that?    Note: I'm not asking this question for myself, but because a question like this seems to be useful for pointing to it when a new feature of TikZ is mentioned in an answer to some other question. Feel free to post answers for any operating system/TeX distribution combination.


I would like to as about adjectives order.  As I understand there is a rule for adjective order in adj adj noun.  Here is my understanding: Opinion>Size>Shape>Age>Color>Nationality/Origin>Material>Purpose  I got it for size - purpose adjectives. But what about opinion?  Does adjective like "hungry", "curious", "playful", "crazy" categorized as opinion?  Sorry if this sounds like very basic question.   Thanks in advance mate!

I remember being taught that the correct order of adjectives in English was something along the lines of "Opinion-Size-Age-Color-Material-Purpose."  However, it's been a long time and I'm pretty sure I've forgotten a few categories (I think there were eight or nine). Can anyone fill them in?


Producing visible light from a radio wave transmitter: why is it not possible? If it is, what are the limitations?

If a radio could produce waves in the visible light spectrum, what would the result be?  This is a thought experiment that I've pondered for a few years now.  I realize there are a few/many real-world constraints, but if we lifted these constraints for the sake of thought, what could we expect?  Personally, I don't see why we wouldn't observe visible light emitting from the antenna, disregarding any light from Blackbody Radiation.


I am not so expert in java as i am learning .I am facing that error at :  charArrays = s.toCharArray(); I don't know the reasons. Though i have made array size too big but still unclear.  I have added another function which is sending to crossover   .....             public void chr_intval(){             int[] array = new int[100] ;             float[]af = new float[6];              String [] gf =new String[7]; // for generating generation therefore copying              Random randomGenerator = new Random();             System.out.println("Chromosome     Genes    Integer value       f(x)               f'(x)    Fitness ratio");              for(int i=1,j=1 ; i<=6; i++,j++){                 array[i] = randomGenerator.nextInt(100); // generate random 6 integers from 1<x<100                 float[] ar2 = new float[array.length];                 ar2[i]= (float)array[i];                 System.out.println("C"+j+   "            "+Genes(array[i])+"   "+array[i]+"              "+f_x(ar2[i])+"            "+fitness_function(f_x(array[i]))+"    ");//+fit_ratio(fitness_function(f_x(array[i])))); // print c1, c2,....                  af = new float[array.length];             //  gf= new String[array.length];                 af[i]= fitness_function(f_x(array[i]));                 gf[i]= Genes(array[i]);      // send to cross_over       //          System.out.println(fit_ratio(af));              }     //      System.out.print("gf"+gf[2]);             Cross_over(gf,af);         }        public void Cross_over(String[] gf, float[] af) {     // System.out.print("gf"+gf[3]); all values are coming successfully      char[] charArrays = new char[1000];      Character[] characterArray = new Character[charArrays.length];      int i = 0;      for(int j = 0; j < af.length; j++) { // comparing fit-funct         if(af[j] > af[0]){             af[0]= af[j];         }     }     if(af[0] >= 95) {         System.out.println("candidate's fitness "+af[0]);     }     else{  // start cross-over by tokenizing  the array         // charArrays[] = gf.toCharArray();          for (String s : gf) {             charArrays = s.toCharArray(); // <--- Error here         }     }     for(int y = 0; y < 8; y++) {         System.out.print( characterArray[y] );     } }

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


I know this has been covered before in , but I still don't fully understand why cancelling differentials —not just inside an integral, but in general— is not considered okay or valid among mathematicians.  I'm currently studying physics at college, and my teachers —those who are physicists and not mathematicians, at least— do it all the time without it causing any trouble. In fact, the first (and less rigorous) method we were taught for solving differential equations relies heavily on treating differentials like numbers and derivatives like fractions. I don't know if it has a proper name, but I mean something like:  $$ \frac{\text{d}I}{\text{d}t}\cos(\omega t) = I\omega \sin(\omega t)  \implies  \frac{\text{d}I}{I}=\omega \tan(\omega t)\space\text{d}t $$  Now, I know that differentials aren't 'really' numbers. I mean, they can be understood both as the "linear part" of a variation or as a linear form, and the former looks like it should be okay to treat them like numbers.  Even the chain rule and the derivative of inverse functions seem to tell us that treating them like so should be consistent, when you write them using Leibniz's notation.  Is there really a situation where treating differentials like numerators and denominators causes any trouble?

Background  I am a first year calculus student so I would prefer if answers remained in Layman's terms.  It is common knowledge and seems to me a mantra that I keep hearing over and over again to "not treat differentials/derivatives as fractions".  I am of course, in particular, referring to Leibniz notation.  However, aside from a quick response such as "oh, it's because its not a fraction but rather a type of operator", I never really got a full answer as to why we can't treat it as such. It just kind of sits at the edge of taboo in my mind where it sometimes gets used and sometimes doesn't.  Confusion is further compounded when a lot of things seem to just work out if we treat them just as fractions (e.g. u-substitution / related-rates)    Example     Air is being pumped into a balloon at a rate of $100cm^3/s$. We want the rate of change of radius when the radius is at $25cm$.   $$\text{we are given}\ \frac{dv}{dt}=100cm^3/s$$ $$\text{we want}\ \frac{dr}{dt}\ \text{when}\ r=25cm$$ Thus we will solve this by using the relation $v=\frac{4}{3}\pi r^3$ $$\frac{dv}{dt}=\frac{dv}{dr}\frac{dr}{dt}$$ $$\frac{dv}{dt}\frac{dr}{dv}=\frac{dr}{dt}$$ $$100\frac{1}{4\pi r^2}=\frac{1}{25\pi}$$ So the answer is $\frac{dr}{dt}=\frac{1}{25\pi}$ when $r=25cm$  *Note the manipulation of derivatives just as if they were common fractions using algebra.    Question  When exactly can I treat differentials/derivatives as fractions and when can I not?   Please keep in mind that at the end of the day, I am a first year college student. An answer that is easy to understand is preferred over one that is more mathematically rigorous but less friendly to a beginner such as me.


Two questions:   Is there anything in the HNQ algorithm that explicitly prevents a question that was on the list from appearing again at a much later date? E.g. a hard age cutoff or anything? If not, is there an actual risk of this happening / has it ever happened in on a significant scale?   The reason I ask is I am writing a little HNQ tracking app, and the logic that I use to track "time on the list" for questions near the end of the top 100 that may pop off and on it depends on this. So if my questions above aren't the right questions in this context, my real, underlying question is:   If my software defines "time in list" as "last seen in list" - "first seen in list", will this always be sufficient? Or will I have to do more complex logic to avoid weird things like "6 months in the list" if a question reappears?      According to , the hotness formula (not including traffic weighting), is:  (MIN(AnswerCount, 10) * QScore) / 5 + AnswerScore -------------------------------------------------          MAX(QAgeInHours + 1, 6) ^ 1.4   Assuming there are no explicit age limits or other logic, this means that a question may reappear on the HNQ list if its score or answers ever get that weight back to the original x / Age^1.4 line. This seems unlikely.

I really like the , where certain questions from the Stack Exchange Network are presented, along with a hotness rating that is described as "arbitrary" in its tooltip. Such questions also appear randomly on the sidebar on sites across the network, under the heading "Hot Network Questions". How do these arbitrary hotness points work, and how are they used to select questions to appear in those lists?


I'm trying to get a Windows 10 ISO for a virtual campaign soon, but I am unable to find a website that has the Windows 10 ISO. I mostly use WinWorld, but it lacks an ISO, and there's no way of newer versions at the download site.

I need to repair my Windows 10 installation. Where can I get a clean ISO (with install.wim, no Install.ESD, so that I can run DISM against the WIM) of the specific Windows 10 build required for this?  In my case, I need the Anniversary update (Build 14393), Creators Update (Build 15063) or Fall Creators Update (Build 16299.15).


I am using Lenovo A6000 Plus smartphone.  I want to turn off all the animations. But in  Developer options there are only few options. The animation option is missing. I searched but I didn't find anything.   Screenshot (click to enlarge)

How do I set Window animation scale and Transition animation scale to Animation off when  the option to do so is not available on my ROM (though it ought to be). Specifically it should be under Developer options in Settings but all of the User interface options are missing.


Prove that $18!+1$ is divisible by $19$ and $23$  For $19$ we can just use Wilson's Theorem but I wasn't able to think of how to prove for 23. One way is to just multiply $(-5)(-6)(-7)(-8)(-9)(-10)(-11)(11)(10)(9)…(2)(1)$ and then find its remainder with $23$, and then add $1$ to it. But surely there's a better way right?

I was solving some problems and I came across this problem. I didn't understand how to approach this problem. Can we solve this with out actually calculating $18!\,\,?$


Hi  I feel a little bit confused about transforming the parameters of normal distribution to log normal.  I have a random variable that is N(0.06,0.000144). Because this random variable cannot take negative values, I want to use an equivalent lognormal distribution. I calculated the mu (location parameter) as -2.83 and sigma squared (scale parameter) as 0.39. The model that I am using for simulation takes the mean and standard deviation of the lognormal distribution. when I calculate the mean and standard deviation of lognormal using the mu and sigma I get the original mean and standard deviation of the normal distribution. Is that correct? Ps. I used the following formulas to calculate mu, sigma, mean and standard deviation of the lognormal:

I have the mean and median values for a sample drawn from a lognormal distribution. Note that this is not the mean and median of the logs of the variable, though I can of course calculate the logs of the mean and median. Is there a closed form solution for μ and σ from this information? If there is only a numeric solution, could you tell me how to find it, ideally with R?  I note that this question has been answered for deriving μ and σ from the sample mean and the sample variance, here:   However, I do not have the sample variance, only the mean and median.  If there is no closed-form or straightforward numeric solution, I'd like to know if using the logs of the sample mean and median, or some transform of them, will provide a reasonable answer for a large sample (in the hundreds of millions).


I was writing a block of mathematical formulas using the align environment. While I was writing these aligned equations I reached a pagebreak and the whole block moved to the next page so it made me wonder what is the right way to typeset my aligned equations in that case so to have the best output.  That environment doesn't allow pagebreaks as it is mentioned in the Amsmath's user manual so in such a case the author to be responsible for the breaking of the equations.  So in such a case should I leave most of the equations in the align environment till the pagebreak and the rest of them in a new align? If there is only one equation left that doesn't fit in the page should I use again align or a simple equation environment in order to have the same alignment with the previous block of equations? Does the equation environment aligns the one leftover equation the same as the block of equations in the previous page?  Also what should I do in the case that I had used the multiline or one of the other environments?

I got the following problem: Right now I am checking my equations, which are usually written in align. This looks great in most of the cases, but sometimes the pagebreaks are weird, ie there is a lot of vertical whitespace left (like 2.5cm) at the end of a page. I made the following MWE to illustrate this.  \documentclass[a4paper, 12pt, headsepline]{scrreprt} \usepackage[onehalfspacing]{setspace} \usepackage{amsmath, amssymb, mathtools} \usepackage{mathptmx} \usepackage[a4paper]{geometry} \geometry{left=2cm,right=5cm,top=2cm,bottom=2cm} % \usepackage{lipsum} %\lipsum \usepackage[pangram]{blindtext}  \begin{document} \Blindtext[1][3]%1 paragraph, 3 pangrams \begin{align} X_{t+1} &=  \frac{X_{t+1}+X_{t+1}}{Y_t}  \label{eq:1}  \intertext{Solving...:} \notag  X_{t}  &=  \frac{X_{t+1}+X_{t+1}}{Y_{t+1}} \notag \\ \intertext{Solving further...:} \notag  % ===PAGEBREAK HERE: 2nd page begins=== &= \frac{X_{t+1}+X_{t+1}}{Y_t} +  \frac{X_{t+1}+X_{t+1}}{Y_t}  \notag \\ &= \frac{X_{t+1}+X_{t+1}}{Y_t}...  \notag \\ \intertext{Solving further...:} & = \frac{X_{t+1}+X_{t+1}}{Y_t}  \notag \end{align}  \end{document}   In the MWE, the first 'Solving further' should be on the first page instead (to save space and it would also look better I guess?). The position where I would like the pagebreak to be is also marked as a comment in the MWE.  My question is first on a general basis: Which is the best environment to achieve multiple line equations, which can be aligned as in align, and to save space at the same time? Or to be more precise: If possible, I'd like to stick with align and adapt the pagebreaks only if necessary.  Thanks!


I am traveling first time to Canada, I have got the visa for Canada stamped on my old passport. Meantime I applied for new passport because it is going to expire in 4 months. Yesterday I received new passport. Today I received POE letter where it is mentioned that if you obtain new passport before your visa expires you will need to apply for new visa.   In this case what shall I do, please advise what can be the solution for this issue.

I am Indian passport holder, i have Canada visa stamped on old passport, as per PoE letter mentioned I need to apply for visa again if have new passport. Please advise


Can someone explain briefly, or point me to, how to host a LAMP server on a Linux-based VirtualBox (Oracle) such at the web site on the VB are accessible to the outside world?  The Host itself would be a windows machine that is connected to the internet through cable modem.  I'm already familiar with using VirtualBox as a development LAMP. But, the networking aspects of how this works are what I am asking about.

I have a VM webserver setup and I have installed and started Apache.  The VM has a bridged network interface and can be pinged from the host using 192.168.0.2.  However, if I type that same IP address into the browser on the host machine, I was expecting to see the default apache page generated on the VM, but instead, I get can't connect to 192.168.0.2 in the host machines browser.  I've clearly missed something out.  Anyone know what I have missed or done wrong?  Output from VM netstat -tnlp  tcp     0     0 0.0.0.0:22        0.0.0.0:*     LISTEN     950/sshd tcp     0     0 127.0.0.1:25      0.0.0.0:*     LISTEN    1026/master tcp     0     0 :::22                  :::*     LISTEN     904/sshd tcp     0     0 ::1:25                 :::*     LISTEN     980/master   Rough drawing of what I'm thinking the network activity/connectivity would look like.


Once an object or particle passes the event horizon, will it ever reach the center of the blackhole. I ask this from my elementary understand of relativity. This is my understanding: if an object passes the event horizon, essentially, even if it were moving at the speed of light, it couldn't escape. In my mind, the gravitational pull inside the event horizon pulls particles at a speed greater than the speed of light. As time reaches the speed of light it slows down, which means the object exists at time zero. So will it ever reach the center of the blackhole?

I am not a professional physicist, so I may say something rubbish in here, but this question has always popped in my mind every time I read or hear anyone speak of particles hitting singularities and "weird things happen".   Now to the question at hand, please follow my slow reasoning... As far as I've learned, to reach a black hole singularity, you must first cross an event horizon. The event horizon has this particular property of putting the external universe on an infinite speed to the falling observer. Now due to the Hawking radiation, and knowing that the cosmic background radiation is slowly dimming, sooner or later every black hole in this particular instance of inflation we are living in will evaporate, according to an external observer of said black holes.  This means that every black hole has a finite timespan, as long as this universe survives that long. Now if we go back to the falling observer, we had already established that such an observer would see the outside universe "speed up" infinitely. This means that when the falling observer "hits" the event horizon, he will (or it if we speak about particles, which is clearer in this case), be immediately transported in time towards the final evaporation moment of the black hole. Either this or the particle gets some weird treatment. My point is, such a particle never gets to the singularity, because it has no time to get to it. The moment it crosses the event horizon, the black hole itself evaporates.  Where am I wrong here?


Anyone know if R has quote-like operators like Perl's qw() for generating character vectors?


Is there possible to view activity log/history from a list in SharePoint? Not the versioning on an item but I want to see all the activities on the list.  Or do I need to do a custom action for this?

I thought this was simple: I went to list settings --> Information Management Policy Settings, clicked on "item", and on the "edit policy" screen I selected to "enable auditing" and then selected two events: "editing items" and "checking out or checking in". After setting this up and adding and editing some list items, there was nothing in the audit logs (site settings --> audit log reports --> content modifications).   Then, I enabled auditing via site settings --> site collection audit settings, and checked the "editing items" box. At this point, all lists/libraries were being audited and the report had data for all lists/libraries.   So, what exactly does the "enable auditing" in the list settings do? What else do I need to do to audit one particular list?  I tried this in both SharePoint 2013 Enterprise on-prem as well as Office 365 with the same results.


In an HTML file, I have a text field and a button. When the button is pressed, text is added to the to text field via plain JavaScript.  HTML:  please input : <input id="city" type="text" name="city" /> <button onclick="myFunction()">click</button>   JavaScript:  function myFunction() {    var a=document.getElementById("city").value ;    document.getElementById("city").value = a; }   How to set the focus of the text field to the last entered character by using only plain JavaScript, without jQuery or other libraries?  Thank you in advance.

What is the best way (and I presume simplest way) to place the cursor at the end of the text in a input text element via JavaScript - after focus has been set to the element?


When reviewing suggested edits, it often happens that I'd like to say something to the edit suggester, but I can't. The ability to reply to them would be a way to solve edit problems much more amicably, rather than rejecting possibly approvable edits without giving them a reason. Commenting on unrelated posts is clearly not okay. Rejecting the edit with a custom "causes harm" reasoning is also not a good solution, because:  This doesn't notify the edit suggester; they would need to dig out the review for that, which rarely happens. It can only happen when rejecting the suggestion, which is often not my intent.  Besides that:  past approved and binding editors of posts are already reply-able1, there is already an ongoing  to allow replying to rejected editors in comments it's possible for users with pending edit suggestions to edit their edit proposals, so that those edits are also incorporated into the same review (i.e. an unlimited grace period while the edit is still pending) the "Improve Edit" option may not be the right option, as the reviewer may not be entirely aware of what the edit proposer is on to in some cases, or they may need further clarification of the edit before making a decision  I am asking to allow @reply-ing to users who have a pending suggested edit on the post. Note, this does not mean the overloading of their inbox - they won't be notified of all comments, only ones that @-mention their name. Only the post owner would get a notification from all the comments on their post, as normal. Another use case of this feature would be in case someone who has accidentally created a second account or has lost access to their original account suggests an edit to one of their own posts; since the user won't (be able to) see notifications on the first account, one can mention to their second account with the fact that they have another account and instructions to have their account merged. 1As @Glorfindel mentions, they are already pingable. But pending and rejected suggested editors are still not.

Within the canonical answer on  it is clear that post editors can be replied to.      Notifications apply to the author, users with active bounties,   commenters (associated to current non-deleted comments), and editors   of the question or answer that you are commenting on—users not in that   list cannot be notified. You can also notify a ♦ moderator who closed   the question. The question and answers are all considered   independently. For example, if Alice was the author of, commented on,   or edited the question or her answer, then you cannot notify her by   commenting on Bob's answer (unless Alice also participated in that   answer), and vice versa.   However, thanks to , it has become clear that this only applies to approved editors (in addition to binding editors). I wish to request that comment replies be extended to include any user who suggested a rejected edit on the post.  Background The reason I would wish to reply to a rejected editor would be if their edit, while inappropriate, hinted at important information; for example that the answer was wrong or incomplete. In those cases I may wish to encourage them to outline this in a comment or competing answer.


How do I see if an image with 2px or more exist? Current code:  if( $("#imageID").length < 10) {     //Do something    }

Are there any JavaScript or jQuery APIs or methods to get the dimensions of an image on the page?


There is  that addresses this but quickly fix the problem to be something in arthmetics, and in turn what it means for that arithematics problem to be well defined. I have never encontered the definition of "well defined" in a textbook, only in questions where I am asked to show something is well defined For example  Given a functional $$L(f) = \int\limits_0^1 [f^2 - f] dx$$ where $f\in [0,1] \to \mathbb{R}$, $f(0) = 0$ and Lipschitz, show $L(f)$ is well defined  Example 2:  Let $d$ be a metric on $X$, and define the point to set distance $$d(x,C) = \inf\{d(x,y): y \in C\}$$ where $C \subset X$ is a nonempty set Show $d(x,C)$ is well defined  In general, given object $\phi = f$, whatever $\phi, f$ is, what does it mean to show that $\phi$ is well defined?

What exactly makes a function well-defined? I have seen some proofs but they are too hand-wavy and I couldn't understand exactly what a well-defined function is.


When I play a movie with SMPlayer (video:mpv) and I check my CPU usage with GNOME system monitor, it shows %4 or %5 CPU usage (1 second update interval), but htop shows %45 CPU usage:    top shows the same load as htop:    Since My CPU fan RPM goes higher when I'm playing movie with SMPlayer. I suspect top is reporting CPU usage more accurately.  I have Intel i7 920 with 6GB RAM.  Why do I have high CPU usage and why do I see different results on top and in GNOME system monitor?

In the terminal I used "top" to check the processes and how much of the CPU was being used as I thought max was 100%, so I restored 292,000 photos with recoverjpeg on my sda1 HDD, I opened the folder and the Nautalis is  fluctuating between 130% and 170% , should I close the program and am I at risk of my gpu locking up ?


We written if $$f(x_1 + x_2) = f(x_1)f(x_2)$$ means that $f(x) =  a^x$ and this is a characteristic property of the exponential functions.  This to me seems really weird, I am sure that there exist more functions for which this is true. Did the professor make a mistake here?

This is part of a homework assignment for a real analysis course taught out of "Baby Rudin."  Just looking for a push in the right direction, not a full-blown solution.  We are to suppose that $f(x)f(y)=f(x+y)$ for all real x and y, and that f is continuous and not zero.  The first part of this question let me assume differentiability as well, and I was able to compose it with the natural log and take the derivative to prove that $f(x)=e^{cx}$ where c is a real constant.  I'm having a little more trouble only assuming continuity; I'm currently trying to prove that f is differentiable at zero, and hence all real numbers.  Is this an approach worth taking?


This might be a simple question, but how do you evaluate $\int{\sqrt{\tan(x)}\,dx}$ ? I've tried substitution with $u=\tan(x)$, that introduced a $\sec^2(x)$, I've also tried integration by parts, still stuck...

I have been having extreme difficulties with this integral. I would appreciate any and all help. $$ \int \sqrt{\tan x} ~ \mathrm{d}{x}. $$


I have never used Linux based OS and looking forward to use Ubuntu. I want guidance on installing Ubuntu with Windows 8.2 as dual boot?

I'm absolutely new to Linux. I would like to know how to install Ubuntu alongside the pre-installed Windows 8+ OS.  Should I do it with Wubi, or through the Live USB/DVD?  What steps do I need to take to correctly install Ubuntu?


I got this review in the Reopen Queue.        Clicking on Revision I got:        Why are there no changes to diplay if the question is in the queue because of being edited?  If this question is in the queue  (reason 3, thanks @George) and not because of being edited, then the review message/prompt should say that.

Have a look at . It was showing "This question was edited after it was closed" as a reason to reopen. But  was not edited after it was closed.   The last edit was on Oct 26 '08 at 21:15.        And it was closed on Nov 28 '11 at 22:44    Also there is no revision in the review page:        Actually it was in the queue because someone voted to reopen. I think this happens due to   See some examples from Meta review queue:


I've recently noticed  got a down-vote. A lot of good answers contain one, or two down-votes.   Now I realize this is how the system works, and that other users are entitled to have their own opinion on usefulness.   However given:   This is a good, updated answer. No comment was left. This was not the first such answer I noticed.   I don't really understand this voting behavior.    I was wondering if anyone here has any insights on why some people down-vote such questions? What might cause that?  Note: I'm not complaining about it or suggesting a change. I'm genuinely interested in understanding this voting behavior in this case on stack-overflow.

This is a question which started off with a , then turned into an , and now it's a question in its own right (as suggested by Jeff). I'm not sure where it could go from here :)  It's obvious that different people cast downvotes for different reasons. (Upvotes are less controversial, generally.) Here are some possible reasons:   Answer is wrong Answer is misleading (may be technically accurate, but will lead to readers making mistakes) Answer doesn't match the question (e.g. a C# answer to a question about Java) Answer doesn't really address the question, e.g. suggesting a completely different solution, even if the question specifies that there are good reasons why the current approach has to be followed Answer is okay, but not as good as another one which currently has fewer votes Answer appears to be plagiarised from existing answers. Answer is by someone I don't like. Answer is abusive (profanity, spam etc). No reason, I just felt like it. I'm a , and prefer down to up. Have you considered down? Ideological grounds: answer suggests a technology I don't like, or expresses a negative opinion of a technology I do like   Personally I go with 1, 2 and 8 - although I'll add comments suggesting changes in various other situations.  Have I missed anything? What do you do, and why? What are the net benefits (to you, the world in general, and the answerer) from your approach?


looking for the name of a sci-fi short story, 1980's or before. the plot is somewhat like:  father gives kids odd object to play with. the kids play with the object. kids discover 4th of 5th dimension and disappear. father spends rest of his life trying to figure out the object. a quote is from father asking one the children about some pretty view or object and child answers to the effect of "it's not quite right".

I remember reading what I believe is a short story about a brother and sister who somehow come into possession of some toys which turn out to be from aliens. Through playing with them they develop a language their parents can't understand and start to develop mentally far faster than any human.    Does anyone recognize this story, or remember who wrote it or what it's called?


I am getting incorrect result while performing the division using BigDecimal. number1 = 221500.0 number2 = 12.0 Here is my code snippet:  BigDecimal d1 = new BigDecimal(String.valueOf(number1)).setScale(13, 4); BigDecimal d2 = new BigDecimal(String.valueOf(number2)).setScale(13, 4); return (d1.divide(d2, 13, 4 )).doubleValue();   18458.333333333332  if I performed the same calculation using the calculator it gives  18458.333333333333333333333333333  Let me know any issues with handling the scale in BigDecimal. It will be helpful if someone let me know how to arrive the same result with calculator.

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


Sorry for my ignorance regarding Unix but I am puzzled about the behaviour of my Ubuntu (Windows subsystem). I built GNU make from source (because the current version in the repository is still at 4.1 which is from 2014 and buggy) and ran sudo make install as last step. The script ran through without problems and in the following you can see the last few actions of the install procedure, correctly copying make from my install to /usr/local/bin/make. The which command was also of the opinion that I was using /usr/local/bin/make but invoking make still gave me version 4.1 as you can see. Using the full path did the right thing, starting version 4.3. How can this happen? I have knowledge from the stone age that Unix used to employ a file system cache or buffer but I thought this was a transparent thing? Where was make V4.1 buffered in my system?  When I opened a new shell, the behaviour was gone, now correctly using 4.3 when starting make. I know this from the command shell in Windows but can't draw a meaningful connection to the Linux subsystem.  make[2]: Entering directory '/home/user1/install/make-4.3'  /bin/mkdir -p '/usr/local/bin'   /usr/bin/install -c make '/usr/local/bin'  /bin/mkdir -p '/usr/local/include'  /usr/bin/install -c -m 644 src/gnumake.h '/usr/local/include'  /bin/mkdir -p '/usr/local/share/man/man1'  /usr/bin/install -c -m 644 doc/make.1 '/usr/local/share/man/man1' make[2]: Leaving directory '/home/user1/install/make-4.3' make[1]: Leaving directory '/home/user1/install/make-4.3' user1@dogbert:~/install/make-4.3$ make --version GNU Make 4.1 Built for x86_64-pc-linux-gnu Copyright (C) 1988-2014 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. user1@dogbert:~/install/make-4.3$ which make /usr/local/bin/make user1@dogbert:~/install/make-4.3$ ./make --version GNU Make 4.3 Built for x86_64-pc-linux-gnu Copyright (C) 1988-2020 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. user1@dogbert:~/install/make-4.3$ /usr/local/bin/make --version GNU Make 4.3 Built for x86_64-pc-linux-gnu Copyright (C) 1988-2020 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

I have an older version of Git installed at:  /usr/bin/   I recently downloaded a newer version to:  /usr/local/bin   When I type:  which git   I get the location of the old version. I believe that this is just because /usr/bin/ appears before /usr/local/bin in my $PATH variable and so the older version of git is 'found' first.   To test this, I renamed the older version of git to "git_old". Now when I type:  which git   I get the location of the newer version, as expected. But when I type:  git --version   I get the following error:  -bash: /usr/bin/git: No such file or directory   I'm just wondering why my computer is going back to looking in the old location for Git?


I'd like to reproduce a three-column document which contains figures that span the middle column and also protrude slightly into the left and right columns.  The text wraps around the figure.  Here's an example which was fairly simple to mock up in a word processor:    The wrapfig package contains some relatively obscure instructions, not in the main documentation but tucked away in the text file , which explain how to do this manually.  The process is somewhat tedious.  However, that documentation dates from 2003.  I was wondering whether, in the intervening 12 years, anyone has come up with a more convenient way of doing this.

How does one write on the outside of a circle?  I am looking for sample files/packages which imitate a magazine lay-out. Specifically a page with two columns having a circular picture between the two columns.    Example of the desired layout, created using Word:


I have a question? If moving colliding particles create heat then how come the cold wind is not hot but it has moving particals? Why and how do moving particles create heat? Just curios.  Thank You for your answers.

So I was thinking... If heat I feel is just lots of particles going wild and transferring their energy to other bodies, why am I not burned by the wind?  When I thought about it more I figured out that wind usually carries some humidity, and since particles of liquid are moving same speed as the wind, they are basically static relative to each other, so no energy is transferred between them (wind and water particles). And if that water sticks to my skin and wind blows, it'll evaporate thus taking energy from my skin and make me feel cold.  Thing is, I don't think that's really the case but even if it is, if I somehow dry out the wind, will it burn me if it's strong enough? And winds can reach some pretty high velocities (though I must admit I'm not sure if they are comparable to movement of atoms in warm bodies etc...).  So. Bottom line. Can I be burned by wind in some perfect scenario?


I installed Ubuntu Gnome 14.04 a month back. It all worked perfectly but after two days I repeatedly got the notification      File system root low disk space 0 MB left.    I had installed everything correctly, with root space 21 GB. However, I reinstalled Ubuntu to get rid of this, this time with root as 100 GB. It all worked fine for 20 days. But today I started getting the notification again. File system root low disk space- 1 GB left.  I can't find how to resolve this issue. Why is root filling up so fast? Wherever I read, it says 15-20 GB is enough, but even 100GB is apparently not sufficient in my case!

I installed 11.10 ~two weeks ago and run into some strange troubles recently.  Installation was on brand new laptop with clear 160GB SSD. I opted for encrypting home directory. Apart from that I accepted defaults during the installation. There is no other OS on my laptop.  I had circa 40GB in use when (for the third time) I got to see this very unpleasant window:    Twice situation was pretty bad and whole system slowed down considerably. After reboot I could not login to graphical interface (with an error message informing about insufficient space) and had to remove some files from command line first.  Third time I still managed to quickly delete some files and it helped.  My laptop is mainly work environment: so no torrents, games, just two movies. Only media filling space are ~20GB of pictures, and bunch of pdfs. Working mostly on PostgreSQL & PostGIS, GeoServer and QGIS recently.  Although I had lots of opportunities to test and practice my backups I would be extremely grateful if somebody could point me to any potential solutions to this problem.  My laptop has been bought just before I installed Ubuntu, and it came without OS. Could that be hardware issue?  Or is the encrypted home causing me headaches?  Thanks for help!    Update 1: As suggested by , here is current output of fdisk -l:  WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted.   Disk /dev/sda: 160.0 GB, 160041885696 bytes 255 heads, 63 sectors/track, 19457 cylinders, total 312581808 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000     Device Boot      Start         End      Blocks   Id  System /dev/sda1               1   312581807   156290903+  ee  GPT     Update 2: As suggested by , output of df:  Filesystem           1K-blocks      Used Available Use% Mounted on /dev/sda2            149802648  31411456 110781576  23% / udev                   1959764         4   1959760   1% /dev tmpfs                   788276       992    787284   1% /run none                      5120         0      5120   0% /run/lock none                   1970684      2716   1967968   1% /run/shm /dev/sda1                19363       129     19234   1% /boot/efi /home/rdk/.Private   149802648  31411456 110781576  23% /home/rdk   And sudo parted -l:  Model: ATA INTEL SSDSA2BW16 (scsi) Disk /dev/sda: 160GB Sector size (logical/physical): 512B/512B Partition Table: gpt  Number  Start   End     Size    File system  Name  Flags  1      17.4kB  20.0MB  20.0MB  fat16              boot  2      20.0MB  156GB   156GB   ext4  3      156GB   160GB   4177MB     Update 3:  Yet another window with low memory message :/  Working recently mostly on VirtualBox and using Remmina.  Following this information I deleted virtually everything from my home directory. Rebooted. There was ~20GB in use after that [~10GB for VirtualBox disk image which I wanted to keep if possible]. Following  comment I was trying to recover more space and running Bleachbit application when I got another error of low space on HD. Then the system froze. How on earth can my Ubuntu fill up HD with over 100GB within minutes?


The sequence  $$\sum_{n=1}^{\infty} \frac{\sin (n)}{n}$$  converges to a specific value. Convergence tests of any kind are available in a quick search, but I'm struggling to find the proof that this sequence converges to $(\pi - 1)/2$. , complex logarithms are used.  I do not have any knowledge about series and sequences, just a real analysis / real functions background.  Is it possible to make the same proof, using only real functions? If yes, where can I find this proof?

I am a beginner with Fourier series and I have to evaluate the sum   $$\sum_{n  =1}^{\infty}{\sin\left(n\right) \over n}$$  I don't know which function I have to take to evaluate the fourier series ... Someone can give me a hint ?  Thanks in advance!


In a layman sense we called that the black spot of  image is the event horizon. But in some technical references [1] the author said that the black spot actually delimits the photon sphere. I would like to know what is, precisely, that black spot on M87* image: Is the event Horizon or the Photon Sphere?   $$* * *$$ Feel free to be mathematically precise.  $[1]$ GRENZEBACH A. The Shadow of Black Holes.Springer.2016

What exactly is the origin of the orange ring around M$87$?  I understand that the image was not taken in the visible light range. The colors are therefore artificial.   I also read that the image shows the shadow of the black hole on a brighter region of space which is "glowing" gas. Still I wonder about the following:   Why is the bright region circularly shaped and centered around the black hole? Is the bright region at the same distance as the black hole or much further away?


Can anyone clearly explain (with examples) why do we have to change the data type of a dynamic allocation pointer from the default void type into the same data type of its corresponding pointer variable?   ex:  int *ptr = (int *)malloc(sizeof(int));

In , someone suggested in a  that I should not cast the result of malloc. i.e., I should do this: int *sieve = malloc(sizeof(int) * length);  rather than: int *sieve = (int *) malloc(sizeof(int) * length);  Why would this be the case?


I use BibLaTeX with the citation style alphabetic. Sometimes, the abbreviation letters for my citation (e.g. [ABC20]) isn't appropriate for a specific case. For example, if I have a citation of "The Apache Software Foundation", then there will be the abbreviation "[The20]". Instead, I would like it to be e.g. "[Apa20]". Is there any way to achieve this? I am using XeLaTeX in combination with Biber. Update: I wrote a short working example: \documentclass{scrartcl}  \RequirePackage{filecontents}  \begin{filecontents}{example.bib} @software{Lucene.2020,     author = {{The Apache Software Foundation}},     year = {2020},     title = {{Apache Lucene Core}},     version = {8.7.0} } \end{filecontents}  \usepackage[backend=biber,% style=alphabetic,% natbib=true,% hyperref=true,% minnames=1,% maxnames=2]{biblatex}  \renewcommand{\mkbibnamefirst}[1]{\textsc{#1}} \renewcommand{\mkbibnamelast}[1]{\textsc{#1}} \renewcommand{\mkbibnameprefix}[1]{\textsc{#1}} \renewcommand{\mkbibnameaffix}[1]{\textsc{#1}}  \addbibresource{example.bib}  \begin{document}  Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua \parencite{Lucene.2020}.  \printbibliography  \end{document}

I am using biblatex for my bibliography, and the style is alphabetic. More precisely, in the preamble I have  \usepackage[babel]{csquotes} \usepackage[maxnames=99,style=alphabetic,backend=bibtex]{biblatex} \addbibresource{bibliography.bib}   In the bibliography I need to include a two word surname. This is what I have in the .bib file  @article{dJ97, author = {de Jong, A. J.}, title = {Families of curves and alterations}, journaltitle = {Annales de l'institut Fourier}, year = {1997}, volume = {47}, number = {2}, pages = {599-621}, }   In this way, the abbreviation produced is [Jon97], and is alphabetized as a surname starting with J. On the other hand, I have always seen this author alphabetized under d (which I guess should be the correct outcome), and the abbreviation including the "d" of "de". After a quick look online, I just found co-authored works of the author cited in a bibliography style as I have, and the abbreviation is "dJ" followed by other capital letters for the other authors. So, in my case, I guess that the right outcome should be something like [dJo97], or [dJon97].  Which one should the right outcome in my case? How do I get it?


My laptop is running windows 10 and everday it goes for update. now whole C:/windows/ is more than 100 GB. I don't know how to reduce this folder size ( don't what folders to delete ). I cannot repartition hard disk as all windows files belong to disk 0 and other partitions are in disk 1. Is someone facing same issue any solution you followed?

How can I visualize which folders and files are taking up all of the space on my hard drive?  I'm getting some conflicting reports on the size of hard drive contents. Namely what is and isn't there and what folders are actually using the space.   I need to know which of the files or folders the culprits behind all this hidden bloat. Also there should be a print option to get it on paper.


I am trying to curl some URL which returns a json file, then I want to parse hosts from it and create a comma separated string.  I have the first part working   curl -s -u "admin:admin" -H "X-Requested-By: ambari" "https://hbasecluster.net/api/v1/clusters/mycluster/services/ZOOKEEPER/components/ZOOKEEPER_SERVER" | jq -r '.host_components[].HostRoles.host_name'   which returns   zk0-mycluster.net zk1-mycluster.net zk2-mycluster.net   Now I want to join these into one string like  zk0-mycluster.net,zk1-mycluster.net,zk2-mycluster.net

I have a file containing a a large number of lines, each of which contains a bunch of numbers which are separated by spaces. I process this data in a pipe in some way, and then I want to collapse the multiple lines into a single line of all the numbers separated by spaces.  Is there a standard command-line utility I can use to do this? It seems like most line-by-line utilities won't mess with the newlines...


I've been trying to rederive (13.37) from Ashcroft & Mermin:  $$ \sigma_{xy}(\omega+i\eta) = \frac{-ie^2}{\hbar^2(\omega + i\eta)} \sum_{n\neq n'} (f) \left( \frac{\langle n\mathbf k|\nabla_x|n'\mathbf k \rangle \langle n'\mathbf k|\nabla_y|n\mathbf k \rangle}{\hbar\omega + i\eta + \varepsilon_{n\mathbf k} - \varepsilon_{n'\mathbf k}} + \frac{\langle n\mathbf k|\nabla_y|n'\mathbf k \rangle \langle n'\mathbf k|\nabla_x|n\mathbf k \rangle}{-\hbar\omega - i\eta + \varepsilon_{n\mathbf k} - \varepsilon_{n'\mathbf k}} \right).$$  So I understand (pretty much) all derivation steps, but at some point the authors mention the use of time-dependent pertubation theory, p. 252, between (13.36) and (13.37).  I'm assuming the same applies as in appendix E (pp. 765-766), where a Hamiltonian about $\mathbf  k + \mathbf  q$ is considered, $$ H_{\mathbf  k+\mathbf q} = H_{\mathbf k} + \frac{\hbar^2}m \mathbf q \cdot\left(\mathbf k + \frac\nabla i\right) + \frac{\hbar^2}{2m}q^2 $$ where the second and third terms are treated as pertubation $H_1$, and the eigenvalues can correspondingly be $$ \varepsilon_{\mathbf k+\mathbf q} = \varepsilon_{\mathbf k} + \sum_i \frac{\partial\varepsilon}{\partial k_i}q_i + \frac12 \sum_{ij} \frac{\partial^2\varepsilon}{\partial k_i\partial k_j} q_i q_j+ \dots $$  So far so good. I'm assuming I again want to match the orders of q. So since equation (13.34) requires the second order derivative (factors of q of order 2), I will only consider those in the pertubation.  Now I'm getting into territory where I'm not sure I understand. I have $$ A_0(t) = 1$$ and the other coefficient zero. First order approximation gives $$ A_1(t) = 1\quad\text{and}\quad B_1(t) = -\frac i\hbar\int \langle u_{n\mathbf k}| H_1 | u_{n'\mathbf k}\rangle e^{i\frac{\varepsilon_{n\mathbf k} -\varepsilon_{n'\mathbf k}}{\hbar}t}dt$$  This yields three terms for $B_1$, of which two I believe are zero (since the Bloch wave functions are orthogonal), leaving me with $$ B_1(t) = -q\frac{\hbar^2}{m}\frac{\langle u_{n\mathbf k}| \frac{\nabla}i | u_{n'\mathbf k}\rangle}{\varepsilon_{n\mathbf k} - \varepsilon_{n'\mathbf k}} \left[1-\exp\left(i\frac{\varepsilon_{n\mathbf k}-\varepsilon_{n'\mathbf k}}\hbar t\right)\right] $$ Repeating the procedure again, I get $$ A_2(t) = q^2\left(\frac{\hbar^2}{m}\right)^2\frac{\langle u_{n\mathbf k}| \frac{\nabla}i | u_{n'\mathbf k}\rangle\langle u_{n'\mathbf k}| \frac{\nabla}i | u_{n\mathbf k}\rangle}{\varepsilon_{n\mathbf k} - \varepsilon_{n'\mathbf k}} \int \left[\exp\left({i\frac{\varepsilon_{n\mathbf k} - \varepsilon_{n'\mathbf k}}{\hbar} t}\right)-\exp\left(2i\frac{\varepsilon_{n\mathbf k}-\varepsilon_{n'\mathbf k}}\hbar t\right)\right] dt $$ for the $q^2$ term, thus $$ A_2(t) = q^2\left(\frac{\hbar^2}{m}\right)^2\frac{\langle u_{n\mathbf k}| \frac{\nabla}i | u_{n'\mathbf k}\rangle\langle u_{n'\mathbf k}| \frac{\nabla}i | u_{n\mathbf k}\rangle}{\varepsilon_{n\mathbf k} - \varepsilon_{n'\mathbf k}} \left[\frac1{\varepsilon_{n\mathbf k}-\varepsilon_{n'\mathbf k}} - \frac2{\varepsilon_{n\mathbf k}-\varepsilon_{n'\mathbf k}}\right], $$ but I don't think this is correct. The expressions in the multi-level system don't differ very much, so I think the fault in my derivation is more fundamental, but I can't find it.

I am trying to derive the result of the TKNN formula but am experiencing difficulty in deriving the Kubo formula. The Kubo formula used in the TKNN paper is, $$ \sigma_{xy}= \frac{ie^2}{\hbar} \sum_{E^a < E_F < E^b} \frac{\langle a|v_x|b \rangle \langle b|v_y|a \rangle - \langle a|v_y|b \rangle \langle b|v_x|a \rangle}{(E^a - E^b)^2} .$$  The following is my work so far. First of all, from linear response theory, for a general observable, $$ O=\langle\hat{O}(t)\rangle-i\int_{t_0}^{t}\mathrm{d} t' \langle[\hat{O}(t),H_{\mathrm{ext}}(t')]\rangle $$ where $H_{\mathrm{ext}}$ is the perturbing Hamiltonian. Since $H_{\mathrm{ext}}=-\int J\cdot A(r,t)\mathrm{d}^3r$, if we consider current density we have $$ \vec{J}_i(r,t)=\langle j_i(t)\rangle+i\int_{-\infty}^{t}\mathrm{d} t'\int\mathrm{d}^3{r'} \langle[j_i(r,t),j_j(r',t')]\rangle A_j(r',t'). $$ Ignoring the first term, we can rewrite this as $$ \vec{J}_i(r,t)=-\int_{-\infty}^\infty\mathrm{d}t\int \mathrm{d}^3r R_{ij}(r-r',t-t')A_j(r',t') $$ where $$ R_{ij}(r-r',t-t')=-i\theta(t-t')\langle[j_i(r,t),j_j(r',t')]\rangle. $$ We can assume that $A(r,t)=A(r)e^{-i\omega t}$ to show that $E(r,t)=i\omega A(r,t)$. Then by Fourier transforming the expression for the expectation value of the current density, we get $$ \vec{J}(k,\omega)=-\frac{R_{ij}(k,\omega)}{i\omega}E_j(k,\omega) $$ which means DC conductivity is $$ \sigma_{ij}=\lim_{\omega\rightarrow0}\frac{iR_{ij}(k,\omega)}{\omega} $$ The Fourier transform of the response function can be shown to be, $$ R_{ij}(k,\omega)=-i\int_0^\infty \mathrm{d} t e^{i\omega t}\langle[j_i(k,t),j_j(-k,0)]\rangle $$ If we evaluate expectation values using the grand canonical ensemble (ie $\langle \hat{O}\rangle = Tr(e^{-\beta H} \hat{O})/Z$ where $H$ includes the chem. pot.) and integrate over time and perform a first order $\omega$ expansion we end up with $$ R_{ij}(k,\omega)=\sum_{n,m}(e^{-E_m \beta}-e^{-E_n\beta})\left(\frac{\langle n|j_i(k,\omega)|m\rangle\langle m|j_j(-k,\omega)|m\rangle}{E_n-E_m+i\epsilon}-\omega\frac{\langle n|j_i(k,\omega)|m\rangle\langle m|j_j(-k,\omega)|m\rangle}{(E_n-E_m+i\epsilon)^2}\right)/Z $$ This is from where I don't know how to proceed. All derivations for the Kubo formula I have found on this site and other resources online do not consider the position dependence of the current density operator. Any advice that will point me in the right direction will be appreciated.


Basically I am trying to print the number of birds of each specific type in a linked list class I wrote called BirdSurvey. However when I try to print the items using my printList method, I get a nullpointer exception:Exception in thread "main" java.lang.NullPointerException at BirdSurvey.printList(BirdSurvey.java:39).I debugged and I think it has something to do with the my node not being able to find the next item in the list in my if statement. Yes, writing a linked list by hand is my homework assignment but I've come this far on my own so i'm hoping someone could just tell me why I'm getting this exception. class for Birds:      class Birds {     String birdType;     Birds(String birdType)     {         this.birdType = birdType;     }     public String getBirdType()     {         return birdType;     } }   Linked list class for birds:  class BirdSurvey {     static Node head;      static class Node{         Birds data;         Node next;         int count;         Node()         {          }         Node(Birds x)         {             data = x;             next =null;             count =0;         }      }     public void printList()     {         Node _node = head;         while(_node != null)         {             if (_node.data.getBirdType().equals(_node.next.data.getBirdType()))             {                 //increase count if bird species has been seen in list before                 _node.count+=1;             }             _node=_node.next;         }         while(_node != null)         {             //print out the birds and number of times they were in the list             System.out.print("Bird Type:"+_node.data.getBirdType()+" "+ "Count: ");             _node=_node.next;         }     } public static void main(String[] args)     {         BirdSurvey _list = new BirdSurvey();          _list.head = new Node(new Birds("blue jay"));         Node second = new Node(new Birds("orange jay"));         Node third = new Node(new Birds("orange jay"));           _list.head.next=second;         second.next=third;          _list.printList();     } }

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


How to do a full install of the 13.04 onto my pc . I am presently on 11.04 version, & I'm downloading the 13.04 version iso file but how do i do a clean install. regards  Beck

I would like to see a full how-to guide on how to install Ubuntu.


What I want to do is to place a letter on top of another. Specifically because I want to be able to write a specific representation of Greek numerals with large numbers. I just need to be able to put any Greek letter above a Mu or just M in the Greek alphabet. I also want to write some symbols smaller than others. How do I do that?

How could I stack two symbols on top of each other, so that they would appear smaller, i.e. something like \begin{array}a\\b\end{array}, but would fit nicely in a single line with the rest? So for example, I want to write blah blah blah $S(\begin{array}a\\b\end{array})$ blah blah in one single line.  Thanks a lot!


I'm using the below code to split a string based on spaces, unless that space happens inside quotation marks. How can I remove the quotation marks from the final result?  var txt = "PROGRAM \"My ETABS\" VERSION \"9.7.4\"";  string[] split = Regex.Matches(txt, "(\\w+|\".*?\")")                       .Cast<Match>()                       .Select(m => m.Value)                       .ToArray();   Now I have this:  PROGRAM "My ETABS" VERSION "9.7.4"   But I want this:  PROGRAM   My ETABS VERSION  9.7.4

I'm new to regular expressions and would appreciate your help.  I'm trying to put together an expression that will split the example string using all spaces that are not surrounded by single or double quotes. My last attempt looks like this: (?!") and isn't quite working. It's splitting on the space before the quote.  Example input:   This is a string that "will be" highlighted when your 'regular expression' matches something.   Desired output:  This is a string that will be highlighted when your regular expression matches something.   Note that "will be" and 'regular expression' retain the space between the words.


we have a cron job that run every Saturday at 01:00 (0 1 * * 6) we want to modified to run every 2 weeks on Saturday at 01:00.  Thanks.

Today is Friday, October 3, 2014 3:58 AM  I want to schedule a cronjob like that to run it at the following dates:   Saturday, October 4, 2014 8:00 AM Saturday, October 18, 2014 8:00 AM Saturday, November 1, 2014 8:00 AM ... ...   So every 2 weeks , on Saturday, at 8 o'clock.


I'm using GraphPad Prism to generate several graphs. It can export them in some formats, including EPS and PDF. Both are vectorized, both can be implemented in Latex.  So which format is better, and why? PDF seems to be smaller, but the files are sub-megabyte sizes, so I don't care. Is PDF faster, as EPS is implemented (and apparently transcribed to PDF) via epstopdf?

Both are vector graphics (typically) and both can be imported painlessly into a pdflatex document (so let's say we ignore dvi for this question).  What are the advantages and disadvantages of each? What should I use?


Are the number of points I need to answer my own question uniform across all sites?  I could find out by signing up spamming each area but that seems rude.

I might want to answer my own question because:  I arrived at a solution before there were any other correct answers or I like mine better, can I still answer my own question?  I have a folder with lists of code snippets for things I always forget or get wrong, such as regular expressions for processing XML, common WinForms control idioms, etc. Is it considered poor etiquette for Stack Overflow to ask a question I already know the answer to, and then self answer, just so it gets recorded on the website?   Related:          For more information, see "" in the .


Hi I have a question: is there any easy way to extend only the bottom edges of an irregular model (such as in the screenshot) and create a flat base of the model to get the effect shown in the attached drawing? Thanks in advance for the advice!

I am trying to create something like this in Blender, but I don't know how exactly.  I captured a model of a WWI bunker with photogrammetry and processed it with Agisoft Metashape but I like to add an “earth base” for a nicer presentation. I imported the OBJ file into Blender but I'm having trouble making it work (I'm kind of new to Blender). Extruding the model downwards gave bad results, so I tried duplicating the model, making it flat, selecting the edges of both the model and the base with Edge Loops and then Bridging the Edge loops but that gave really funky results (I think not all edges were correctly selected, resulting in an uneven amount of edges between top and bottom).  Could anyone propose a workflow to achieve this in Blender?


Is there a way to use the cprotect package's \cprotEnv command to use verbatim inside environments that have optional or multiple arguments?  My motivation for this question: I am working with exsheets, and want to use \cprotEnv so I can use pythontex's pyblock and pycode inside the exsheet's question environment.   Here's an example that shows the problem. Note that the question's subtitle and point value get messed up.  \documentclass{article} \usepackage{pythontex} \usepackage{exsheets} \usepackage{cprotect} \SetupExSheets{headings=block-subtitle}  \begin{document}  \begin{question}[subtitle = Codeless Question]{10} A question without code, worth 10 points. Subtitle and point values are in correct place. \end{question}  \cprotEnv \begin{question}[subtitle = Codeful Question]{15}  Now with PythonTeX: \begin{pyblock} print("hello, world!") sum = 0 for j in range(0,100)     sum += j print(sum) \end{pyblock}  \end{question}  \end{document}     Edit: I disagree that this question is a duplicate of  . The linked question is about using PythonTeX with exsheets. Although using PythonTeX with exsheets is the motivation for my question, I am asking specifically about the cprotect package. The linked question (and answers therein) do not mention the cprotect package at all.

I am using exsheets and pythontex packages in order to make a book of exercises. I have noticed that pycode environment cannot be used inside question (or solution) environment of exsheets. However, \pyc command works normaly within question.  The easiest workaround is to write pycode outside of solution and, in nutshell, that works for me. However, I would like to understand the reason behind this limitation.  \documentclass{article} \usepackage{pythontex} \usepackage{exsheets}  \begin{document}     \begin{question}         \begin{pycode}          i_Go = J_L * J_M         \end{pycode}     \end{question} \end{document}


I have a text-file that is being continually written to by another program. gedit can refresh the text file contents by going to File -> Revert, but this requires manual input. Is there a text-file viewer (doesn't have to be GUI, a terminal viewer works fine) that automatically updates the contents of the file without manual input?

Is there any console- or window-based text editor that automatically reloads file changed on disk without prompting anything?


I have  PHP 5.6 and 7.1 on my system. I want to use PHP 5.6 for the Drupal 7 projects, and PHP 7.1 for the Drupal 8 projects.  I am having problems getting this setup. In the  I found that I should set an alias like this in my ~/.zshrc.   alias drush='DRUSH_PHP=/usr/bin/php56 /usr/bin/drush'   The problem is that when I start a new terminal and run drush ev 'print PHP_VERSION', it still prints out 7.1.6.  I tried to alias PHP to /usr/bin/php56 but that also did not work.  I also tried the following suggestions (and many others), but they didn't work.        I think this changed in more recent Drush versions, like version 8.1.12 I am using.  Can anyone help me find the correct way to do this in more modern Drush versions?

I'm running Drush on a host that has multiple versions of PHP installed. By default, php --version would give you 5.2.x, but php53 and php54 are also available. So in my .bash_profile I have alias php='php53' (php --version = 5.3.13), which makes Drush work for some commands.  However, I still get "Your command line PHP installation is too old. Drush requires at least PHP 5.3.2" messages for some very useful commands.  A couple of really annoying instances:   drush pm-update will report that it has backed up and then updated all modules and core successfully, then return the PHP version error and restore all backups. In verbose mode, the command that comes before the error is: php /home/[username]/drush/drush.php  --backend=2 --verbose --root=/home/[username]/webapps/drup --uri=http://[domain name]  pm-updatecode-postupdate 2>&1 drush archive-dump will immediately return the PHP version error   The other commands I have tried so far work fine. I'm not sure why this would be, if Drush is sometimes using the php53 binary, and other times not, or if it just has trouble detecting the version correctly, but some very important features are broken for me.


I have an array with loads of dictionaries in it. However I want to sort dictionaries in a way where I have maximum value to a specific key in a dictionary. For example I have a list that looks like this  [     {         "num_gurus": 40,         "id": 119749,         "code": null,         "name": "ART 198P",         "short_name": "ART 198P",         "title": "Directed Group Study",         "department_long": null,         "full_name": "Directed Group Study",         "department_short": "ART"     },     {         "num_gurus": 3,         "id": 119825,         "code": null,         "name": "ASAMST 198P",         "short_name": "ASAMST 198P",         "title": "Supervised Group Study",         "department_long": null,         "full_name": "Supervised Group Study",         "department_short": "ASAMST"     },     {         "num_gurus": 200,         "id": 119904,         "code": null,         "name": "AST 636",         "short_name": "AST 636",         "title": "Baudelaire: Art Poetry Modernity",         "department_long": null,         "full_name": "Baudelaire: Art Poetry Modernity",         "department_short": "AST"     } ]   I want my output to sort my dictionaries where the value of a key attribute 'num_gurus' is maximum to minimum. Expected output would be.  [     {         "num_gurus": 200,         "id": 119904,         "code": null,         "name": "AST 636",         "short_name": "AST 636",         "title": "Baudelaire: Art Poetry Modernity",         "department_long": null,         "full_name": "Baudelaire: Art Poetry Modernity",         "department_short": "AST"     }     {         "num_gurus": 40,         "id": 119749,         "code": null,         "name": "ART 198P",         "short_name": "ART 198P",         "title": "Directed Group Study",         "department_long": null,         "full_name": "Directed Group Study",         "department_short": "ART"     },     {         "num_gurus": 3,         "id": 119825,         "code": null,         "name": "ASAMST 198P",         "short_name": "ASAMST 198P",         "title": "Supervised Group Study",         "department_long": null,         "full_name": "Supervised Group Study",         "department_short": "ASAMST"     }  ]   I have tried this so far      for items in load_as_json:             for key, val in sorted(items['num_gurus'].iteritems(), key=lambda (k,v): (v,k), reverse=True):                 print key,val  This throws me error and doesn't do what I actually want to. This is the error I got.   File "utils.py", line 61, in GetPopularCoursesBasedOnGurus     for key, val in sorted(str(items['num_gurus']).iteritems(), key=lambda (k,v): (v,k)): AttributeError: 'str' object has no attribute 'iteritems'

I have a list of dictionaries and want each item to be sorted by a specific value. Take into consideration the list: [{'name':'Homer', 'age':39}, {'name':'Bart', 'age':10}]  When sorted by name, it should become: [{'name':'Bart', 'age':10}, {'name':'Homer', 'age':39}]


I know I cannot do:  var elements = this.template.querySelectorAll('[id^="fieldName"]')[0]; elements[0].getElementsByTagName('lightning-formatted-text')[0].setAttribute("style:", "myCSSAttribute:myCSSValue");   Does this mean then, that, I would also not be able to do something like   var elements = this.template.querySelectorAll('[id^="fieldName"]')[0];  elements.$(lightning-formatted-text')[0].setAttribute("style:", "styleattribute:value");   If that makes sense? I've been trying to see if I'm doing this syntactically wrong or if there is another way to achieve the same result??  Here is my template markup  <template>     <lightning-record-view-form record-id={recordId} object-api-name={objectApiName}>         <template for:each={fieldsArray} for:item='field'>
<lightning-output-field id={field} field-name={field}></lightning-output-field>
         </template>     </lightning-record-view-form>     {dataStyleRulesList}
testidcontent
 </template>   And, I've loaded Jquery as a module like so:  import { LightningElement, api, wire } from 'lwc'; import { loadScript } from 'lightning/platformResourceLoader'; import getDataStyleRules from '@salesforce/apex/CustomMetaDataService.getDataStyleRulesForFields'; import jQuery from '@salesforce/resourceUrl/jquery';   ...   callAfterRenderAll() { $("#testid").attr("style", "background-color:green");$("#testid").attr("style", "background-color:green"); }

How can I change the colors of lightning-button?  I tried doing this in my css:  .my-button {     background-color: #14a6bc;     color: #ffffff; }   and applying that class to my <lightning-button> and removing the variant but I still get the base colors? I am trying to use these examples:


I think the book had dragon in the title not too sure. The older sister I think had ability to control fire I think. They somehow ended up in a castle. I can't remember much of it.

I read this novel when I was young. It is probably a children's or young adult novel. I think I read it in 1997 or earlier. I remember very much enjoying it, but the title and most of the details are unfortunately quite hazy for me. Here is what I have:   The main character was a girl in her early teens (I think) She was sent to live with a man who was some sort of master of dragons She may have been related to this man (his niece, perhaps), but I also may have made that up The man wore gloves at all times. When he removed them and touched someone he could see something about them. Their future, I think?   Sound familiar to anyone?   Update: Thinking back on it some more, I think I remember that the dragon lord guy and the heroine ended up in some kind of romantic relationship (making it less likely that he was her uncle). Also, he did at one point take off his gloves and touch her, seeing her future (I think).  'nother Update: It's possible that I'm confusing dragons with volcanos. Or, there may have been both. And I think they lived on an island, or a coastline?


I have a Gmail account that I use for my personal use, I am also now starting as a Gmail business user and can see I am already going to need another two email accounts.  I thought I would be able to pull those business accounts into my personal email, but I keep running into trouble, I thought it would be easier.  Is there a good, right way to do this?

Possible Duplicate:          I want to login in two users to Gmail using IE.  The problem is that even when I open a new instance the already logged in user will be logged in. And when I log out then the other instance will be logged off.  Any idea?


In C++, is it possible to write code / a Makefile that exports a function from a pre-written C++ file to a shared object - i.e. a DLL / SO file. As an example, let's assume I have the follow file and function definitions. # funcs.cpp int add(int x, int y) {     return x + y; }   To make a Windows DLL, I can modify the above by changing the first line to: extern "C" __declspec(dllexport) int add(int x, int y)  and using a Makefile containing: #Makefile dll: funcs.cpp     g++ -shared funcs.cpp -o output.dll  However, is this possible for the situation where I cannot modify the funcs.cpp file. i.e. How can I package pre-written functions into a shared object please? NOTE: This question got closed as being already answered here:  However, that question is different and it's not clear how to export to DLL without adding _declspec(dllexport) to the original cpp file. If it's easy and I'm in fact missing something, perhaps someone could post the answer or otherwise, can the question be re-opened please?

I'd like a simple example of exporting a function from a C++ Windows DLL.  I'd like to see the header, the .cpp file, and the .def file (if absolutely required).  I'd like the exported name to be undecorated. I'd like to use the most standard calling convention (__stdcall?). I'd like the use __declspec(dllexport) and not have to use a .def file.  For example:    //header   extern "C"   {    __declspec(dllexport) int __stdcall foo(long bar);   }    //cpp   int __stdcall foo(long bar)   {     return 0;   }   I'm trying to avoid the linker added underscores and/or numbers (byte counts?) to the name.   I'm OK with not supporting dllimport and dllexport using the same header. I don't want any information about exporting C++ class methods, just c-style global functions.  UPDATE  Not including the calling convention (and using extern "C") gives me the export names as I like, but what does that mean? Is whatever default calling convention I'm getting what pinvoke (.NET), declare (vb6), and GetProcAddress would expect? (I guess for GetProcAddress it would depend on the function pointer the caller created).  I want this DLL to be used without a header file, so I don't really need the a lot of the fancy #defines to make the header usable by a caller.  I'm OK with an answer being that I have to use a *.def file.


This is what I have:  if (balance * 100 % 10 == 0) {     balance = balance + 0.00; } if (balance > 0) {     return name + ", $" + balance; } else if (balance < 0) {     return name + ", -$" + -balance; } else { // balance = 0     return name + ", $0.00"; }   I want to return "$4.80" but I keep getting "$4.8". How do I get the 0 at the end of the decimal?

How do I format a number in Java? What are the "Best Practices"? Will I need to round a number before I format it?  32.302342342342343 => 32.30 .7323 => 0.73  etc.


So at the end of Age of Ultron, during the post credit scene, we see Thanos grab a gauntlet (not sure from where) and says "Fine, I'll do it myself" or something like that, he puts on the gauntlet, end scene.  But we know that the gauntlet he is currently using was from Eitri's forge on Nidavellir.  Is that the same gauntlet?  I think that maybe it was the "fake" one that Hela knocks over.  Or could it be that the other gauntlet was lost, stolen, or fake?

Way back in Thor, there was an Easter Egg Infinity Gauntlet in Odin's vault.  They even  that year to show it off.  Presently in the Marvel Cinematic Universe, they're clearly building to an Infinity Gauntlet story, and they've shown several Infinity Stones out in the universe.  The Infinity Stones are clearly not all sitting in Odin's vault, on a gauntlet.  Has Marvel commented on this issue at all in interviews?  Has the gauntlet been retconned into being some other gauntlet, or some other piece of the Infinity Gauntlet puzzle?


I'm not able to display ñ on a web I'm using to learn to code.    mysql database has latin1_spanish_ci collation. I've tried setting collation to utf-8, using decode(utf-8), setting the page charset to charset=ISO-8859-1, but nothing seems to work.  This is the php code  index.php  <!DOCTYPE html>           <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" />         <title>             Bitácora         </title>           <?php require_once('db_conn.php');?>     <?php require_once('script.php');?>     <?php if($_COOKIE['username'] === NULL){         header("Location: login.php");         } else {         //         }     ?>

Estás logueado como " <?php echo ucwords(strtolower($row['nombre'])) . " " . ucwords(strtolower($row['apellido'])); ?>"

     <form action="inserta.php" id="formaLog" name="formaLog" method="POST">     <textarea style="overflow:auto;resize:none" rows="4" cols="80" id="log" name="log" required></textarea>     <input type="submit" name="envia" value="Enviar" id="envia" />     </form>
   <?php require_once('menu.php'); ?>      script.php  <?php require_once('db_conn.php');   $dbc = mysqli_connect(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME);      if( isset($_COOKIE['user_id']) ){     //  mysqli_set_charset($dbc,"utf8");     // Look up the username and password in the database         $username = $_COOKIE['username'];         $id = $_COOKIE['user_id'];         $query = "SELECT id, username, nombre, apellido FROM usuarios WHERE username = '$username'";         $data = mysqli_query($dbc, $query);           if (mysqli_num_rows($data) == 1) {     // The log-in is OK so set the user ID and username cookies, and redirect to the home page         $row = mysqli_fetch_array($data);          }     }  ?>

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1.  Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur?  This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2.


How can I edit Plymouth with my own theme (images and animations)?

I would love an animated splash screen, just for a bit of eye candy to replace the purple splash (with 4 dots) during the boot sequence. I know it will slow down boot time but I don't care I just want it to look good. When I show my friends how much better looking Ubuntu is than windows the splash really lets it down.   Any one know a good alternative to the existing Plymouth boot?  I could not get mine to change the splash screen (with terminal or gui apps), and it is now broken, it just shows a load of error messages at boot but still starts Ubuntu.


What is the British English way of referring to a source in-text.  Is it plural because there are two authors, like this:         X and Y (2011) describe ...   Or is it singular because you are referring to a singular source, like this:     X and Y (2011) describes...   So what I am asking is whether you refer to the source or to the authors?

When referencing to another work in a scientific paper, do we cite the paper or its author(s)?  This question is intended to clarify the conjugation of the verb that follows the reference -- especially in these cases:   One author, two papers:     Jane Doe (2015a, 2015b) list-s the very specific conditions under which...   -> lists (singular: referencing to Jane Doe) or list (plural: referencing to both papers) Several authors, one paper:     John Doe, et al. (2015) claim-s this and that.   -> claim (plural: referencing to the multiple authors of the paper) or claims (singular: referencing to the single paper).


I have 17.10 installed in a dual-boot with Windows 7 pro on a home built AMD machine.  When I log in, it tells me that 17.10 is no longer supported and I should upgrade to 18.04LTS.  When I click "upgrade" it asks for authentication, which I provide.  Then nothing happens.  If I click the software updater (icon with tools) it searches, then says it cannot connect to the repository and to check my internet connection, which is working fine at about 500 Mb hardwired to Comcast.  Then it again gives me the message saying I should upgrade...  Tried this 3 times with no results.  What can you suggest?  I really don't want to screw up the dual boot installation.

Recently I have installed an older version of Ubuntu on my old machine. Whenever I try to install any software, I get an error saying it couldn't be found:  $ sudo apt-get install vlc Reading package lists... Done                Building dependency tree        Reading state information... Done     E: Couldn't find package vlc


i dont know what a 'squash' is, is this a new feature or a bug? should i report this?

I just realized using gnome-disk-utility (3.18.3.1) that my 16.04 installation is featuring several small loop devices.  In detail:   78 MB Loop Device (/var/lib/snapd/sn_ntu-core_352.snap -> /dev/loop0) 76 MB Loop Device (/var/lib/snapd/sn_ntu-core_216.snap -> /dev/loop1) 79 MB Loop Device (/var/lib/snapd/sn_ntu-core_423.snap -> /dev/loop2) 705 KB Loop Device (/var/lib/snapd/snaps/tpad_12.snap -> /dev/loop3) 684 KB Loop Device (/var/lib/snapd/snaps/tpad_11.snap -> /dev/loop5) 705 KB Loop Device (/var/lib/snapd/snaps/tpad_13.snap -> /dev/loop6)   Image showing gnome-disk-utility    My questions are as follows:   What are those loop devices used for? Is that an expected behaviour in 16.04? Can  I remove them? And if so - how (just by unmounting)? Is there any risk in removing the 2 installed snaps mentioned below (tpad and ubuntu-core)   UPDATE  Installed snaps  According to snap list I do have   tpad (1.8.1) ubuntu-core (16.04.1)   installed. I remember I did tinker with snaps for a short time when  I realized this option - but am pretty unsure if  I  installed those 2 snaps - or if they are pre-/auto-installed.  tpad is a Terminal text editor with GUI-like user interface  I  did install manually, as  I don't use it  I removed it now via sudo snap remove tpad. As a result the 2 loop devices pointing to tpad are gone in gnome-disk-utility.  So - at the current point  I am still having 1 snap installed called ubuntu-core and I don't know what it is used for. The summary of this particular snap is   The ubuntu-core OS snap


I have a large table (height does not fit in page) and I use this code in order to fit it in height.  \begin{table}[] \resizebox{!}{0.65\textheight}{ \begin{tabular}{lllll}  ...  \end{tabular}} \end{table}   The problem is that the table shrinks also in width. Is it possible to keep the original width of the table but shrink in height in order to fit in page?  I do not want to use some special packages here.

I have a table that I want to insert on a page, but at least one (perhaps both) of the following conditions are met:   The table is too wide to fit within the text block or page. That is, I'm exceeding some horizontal restriction. The table is too tall to fit within the text block or page. That is, I'm exceeding some vertical restriction.   What are my options to make this table fit? If it doesn't fit, regardless of my attempts, what other options exist?


Here is my question, what video driver/config files do I need to backup if I break my system by playing around with the settings?  So, I am still stuggling to get my Geforce working to my satisfaction (display freezes periodically, sometimes the system completely locks up, I use the REISUB quite a lot).  If I start VLC or Mplayer in auto-fullscreen mode it often locks up.  Bootup is always hit or miss, I get the login screen, but it will not accept input, just frozen.  Hard reboot time, I don't like a hard reboot, feel like an amateur.  If the system freezes, it will not allow Ctrl+Alt+Fx, and not always REISUB.  So I'm going to try various drivers and configurations until I get it right.  I'm running Ubuntu 16.04 LTS.     Intel Core i7.      00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)      01:00.0 VGA compatible controller: NVIDIA Corporation GF108M [GeForce GT 555M] (rev a1)   I have an SSD as well, but this version of Ubuntu is very laggy, buggy, just not as good as I'd like.  What do you all think?  What should I backup?  Thanks a lot folks.  When I crack this, I'll post a full report.  Did I format this post correctly?

I want to use version control for config files in Ubuntu server.    But I found it's not easy to simply use git for the whole /etc directory, because many files don't need to be tracked and sometimes the system will write to files like logs which should be ignored.    Is there an application that can do this and make it easy? If it is based on git that is better.


Edit : other answer talked about change the title of the terminal, not a tab, but effectively they answer to my question too. Everything is great.  I'm a newbie and I wonder how give a specific name to a terminal tab instance ?  Here an instance of my question :     Currently I have just few knowledge in Ubuntu system. Thanks

When I was using ubuntu 14.04, it's easy to set title. Just press F2 or move mouse to top menu. But there is no menu on ubuntu 16.04 and press F2 can't change the title. What should I do?


I have to calculate $ \lim_{\left(x,y\right)\to\left(0,0\right)}\frac{\sin\left(x^{3}+y^{3}\right)}{\sin\left(x^{2}+y^{2}\right)} $ From wolfram calculator I know the limit is $ 0 $. The onl way I cant think of proving it is switch to polar, and to show that $ \lim_{r\to0}\frac{\sin\left(r^{3}\left(\cos^{3}\theta+\sin^{3}\theta\right)\right)}{\sin\left(r^{2}\right)} $ is $ 0$. If I'll treat $ \theta $ as a constant and I'll get that the limit is zero, is that mean that from any direction that the function getting closer to zero, the limit is zero? If so, I could show it using l'Hospital's rule and I guess it would be easy, but I'm not sure its legit. Thanks in advance

Find $$\lim_{(x,y) \to (0,0)}  \frac{\tan(x^3+y^3)}{\sin(x^2+y^2)}$$  What do you guys think about this approach, and are there any faster and easier approaches? My approach:   $\frac{\tan(x^3+y^3)(x^2+y^2)}{\sin(x^2+y^2)(x^2+y^2)}$  2.$\frac{\tan(x^3+y^3)}{(x^2+y^2)}$  $\frac{\sin(x^3+y^3)}{\cos(x^3+y^3)\rightarrow 1(x^2+y^2)}$  $\frac{\sin(x^3+y^3)}{(x^2+y^2)}$  Polar: $rcos^3\phi + rsin^3\phi = 0 + 0 = 0$    Thus, $$\lim_{(x,y) \to (0,0)}  \frac{\tan(x^3+y^3)}{\sin(x^2+y^2)} = 0$$