Could someone please explain the concept of identifiability of parameters for some statistical model? I am having some difficulties to understand the concept  and how to derive it say for example from the poisson or exponential distribution. I understand that the gist of it is that if two identical parameters should generate the same probability distribution. Could you please explain a bit more in detail this concept and when it does not work? Thank you SB

I know that with a model that is not identifiable the data can be said to be generated by multiple different assignments to the model parameters. I know that sometimes it's possible to constrain parameters so that all are identifiable, as in the example in Cassella & Berger 2nd ed, section 11.2.  Given a particular model, how can I evaluate whether or not it's identifiable?


I would like to upmix 2 channel audio sources such that they use all of my 5.1 speakers. I have a realtek sound card (with updated drivers) and Windows 7.   Here's what i've tried:    Using the "Speaker Fill" option under the speaker properties "Enhancements" tab. This tries to guess what the audio should sound like in a 5.1 environment which results in only parts of the audio being played out of the additional speakers. I could deal with that if it were only the rear speakers but it also impacts the sub too. The 2 channel audio sources have significantly less low-end than true 5.1 sources when using "Speaker Fill".       Using the "Room" environment. This seems to help a bit but it also introduces a slight echo effect/distortion that can be annoying with certain music/sources.      I'm MusicBee for playing music as it has it's own upmix option that works perfectly. The rear speakers are exact clones of the front speakers and the subwoofer sounds great too. I'd love to be able to have that same quality upmix with other sources such as YouTube.   Are there any other options out there?  Related:

Is it possible to "upmix" (split) stereo output from games, winamp, youtube and so on through 5.1 speaker set? Movies from DVD or some games uses all 6 speakers, but most of today's usage does not.  I know foobar2000 can upmix stereo MP3 to all speakers, I'd like to process all stereo sound that way.  Is there any solution for Windows XP or 7?  EDIT: I'm talking about onboard 5.1 sound output AC97 nForce2 chipset in my case. Definitely low-end. EDIT2: No digital output, 3 analog mini-jacks there.


I just installed phpMyAdmin on a clean Ubuntu Server 13.04 installation. Everything in the application works, except for the "Settings" page. This one page is blank when I click on it and when I attempt to view the source code there is nothing in the source. If I cat the file I can see that the file is not empty. The error log is not helpful - nothing is logged when attempting to view the page. How can I debug or fix this?

phpMyAdmin works well except for a couple of links on the Home Page.  There are two links to More Settings, however they both take me to a blank page.   Am I missing a module, or does it need reinstalling?  The apache error.log reports:  [Fri May 31 09:22:06 2013] [notice] caught SIGTERM, shutting down [Fri May 31 09:23:04 2013] [notice] Apache/2.2.22 (Ubuntu) PHP/5.4.9-4ubuntu2 configured -- resuming normal operations [Fri May 31 11:14:32 2013] [notice] caught SIGTERM, shutting down [Fri May 31 11:15:52 2013] [notice] Apache/2.2.22 (Ubuntu) PHP/5.4.9-4ubuntu2 configured -- resuming normal operations   Thanks


I have tried burning Ubuntu 12.04 to disc by using Nero and also using infrarecorder.    When i use infrarecorder and burn as image and check files on disc, I only get four files and not the reset.    I have seen in how to burn in Ubuntu help, that I am not getting the full operating system to burn.    I am not sure if this is down to my equipment, or down to iso file itself.    At present I'm using Windows xp, and worried if I continue after April 8th I will start to run in to problems.   I just need to burn Ubuntu iso file properly so I can use it as a dual boot up.

I have downloaded an ISO file recently.  How do I burn it to a CD or DVD or mount it?


If $x,y,z>0$ and $x+y+z=60$. Then minimum value of $\displaystyle \frac{x^2+y^2}{x+y}+\frac{y^2+z^2}{y+z}+\frac{z^2+x^2}{z+x}$   Try: $$\frac{(x+y)^2-2xy}{x+y}+\frac{(y+z)^2-2yz}{y+z}+\frac{(z+x)^2-2zx}{z+x}$$  So $$2(x+y+z)-2\bigg[\frac{xy}{x+y}+\frac{yz}{y+z}+\frac{zx}{z+x}\bigg]$$  Now Using arithmetic geometric inequality  $x+y\geq 2\sqrt{xy}$ and $y+z\geq 2\sqrt{yz}$ and $z+x\geq 2\sqrt{zx}$  Could some help me how to solve further, Thanks

If $a,b,c$ are positive , show that $$\dfrac{b^2+c^2}{b+c}+\dfrac{c^2+a^2}{c+a}+\dfrac{a^2+b^2}{a+b} \ge a+b+c$$  Trial: Here  I proceed in this way $$\dfrac{b^2+c^2}{b+c}+\dfrac{c^2+a^2}{c+a}+\dfrac{a^2+b^2}{a+b} \ge  \dfrac{2bc}{b+c}+\dfrac{2ca}{c+a}+\dfrac{2ab}{a+b}$$ then how I proceed. Please help.


When taking the ferry from Belfast to Liverpool do you need identification?

Can you travel from Northern Ireland to Britain without a passport or driver's license? In theory there are no border checks but ferries seem to demand photo ID.


I need to show that the extension $\mathbb{Q}(\sqrt{2+\sqrt{2}})$ is Galois over $\mathbb{Q}$, and compute its Galois group.   I am learning Galois theory by myself and got stuck in this exercise. I know the fundamental theorem of Galois theory. Any help would be useful  Thanks

So I want to show that $\mathbb{Q}(\sqrt{2+\sqrt{2}})$ is Galois over $\mathbb{Q}$ and determine its Galois group.   My thoughts are as follows:  Define $\alpha := \sqrt{2+\sqrt{2}}$. Then it is easily shown that $\alpha$ satisfies $\alpha^4-4\alpha^2+2=0$.  Define $f(x) := x^4-4x^2+2$. Then $f$ is irreducible over $\mathbb{Q}$ by Eisenstein with $p=2$.  So we have that $f$ is the irreducible polynomial for $\alpha$ over $\mathbb{Q}$.   Further $|\mathbb{Q}(\alpha):\mathbb{Q}|=4$.  For $\mathbb{Q}({\alpha})$ to be Galois, it must contain all roots of $f$.   Define $K=\mathbb{Q}(\alpha)$ for convenience.  Define $\alpha := \alpha_1$.  Since $f$ has only even powers, we know that $-\alpha := \alpha_2$ is a root, and therefore contained in $K$ since $K$ is a field.  We note that the other two roots are $\alpha_3=\sqrt{2-\sqrt{2}}$ and $\alpha_4=-\sqrt{2-\sqrt{2}}$.  So in order to show $K$ is Galois, it must be shown that $\alpha_3$ and $\alpha_4$ lie in $K$.  Now $\alpha_1^2=2+\sqrt2$ and so $\sqrt2 \in K$. Thus $-\sqrt2 \in K$ since $K$ is a field.  Can somebody explain why $\alpha_3$ and $\alpha_4$ lie in $K$?  Next we are to determine the Galois group of $K$.  Assuming $K$ is Galois, since it has degree $4$ over $\mathbb{Q}$ (shown earlier), we know that its Galois group has size $4$. There are only two groups of size $4$, namely $V_4$ and $C_4$, the Klein four group and the cyclic group of order $4$.  How do we determine which of these choice is in fact the Galois Group?


Google+ hangouts are actually a reason to use Google+. The introduction of screen sharing, makes it that much more compelling to use it with work teams and small groups. Out of the box Google+ scales the shared screen so much that it's unreadable. Is there any way around this?

We would like to use Google Hangouts for corporate multi-user communication, mainly for screensharing. The default setting does not support fullscreen mode, the only option is to resize the browser window to fullscreen (F11). Unfortunatelly with this the screen share size is still not big enough.  Is there any way way to use Hangouts in fullscreen mode?  Skype is not an option because the free version does not support multi-user webcam/screenshare conference.


I have a container (assume open on top) with $1m^3$ of water. That water exits this container from an opening that has a cross-section area A e.g. $πR^2$ = $1cm^2$.    What is the volumetric flow rate I get out of this opening? I have a feeling that it's related to $R^4$ due to  but on the other hand it has the $|DP|$ that might also be related to R in some way. Is there any way to force the volumetric flow rate to be ~$R^2$ (e.g. adjusting the pressure with a mechanical way?)

Poiseuille's law states that the rate of flow of water is proportionate to $r^4$ where $r$ is the radius of the pipe. I don't see why.  Intuitively I would expect rate of flow of fluid to vary with $r^2$ as the volume of a cylinder varies with $r^2$ for a constant length. The volume that flows past a point is equal to rate of flow fluid, and thus it should vary with $r^2$.  I cannot understand the mathematical proof completely. Is there an intuitive explanation for this?


I'm trying to clip a raster using gdal.Translate but i get this error message:   Traceback (most recent call last):   File "C:/Users/Mouqsit/Desktop/test.py", line 6, in <module>     ds = gdal.Translate("C:\\wamp\\www\\Donnees_CRTS\\irrisat_dessimination-smiej\\new.tif", ds, projWin = [681483.831264, 3558183.87652, 747933.831264, 3607833.87652]) AttributeError: 'module' object has no attribute 'Translate'   This is my code:  from osgeo import gdal import sys ,os output_dir='C:\\wamp\\www\\Donnees_CRTS\\irrisat_dessimination-smiej' etp = os.path.join(output_dir,"L8_L8_ETpot_24_30m_2016_223.tif") ds = gdal.Open(etp) ds = gdal.Translate("C:\\wamp\\www\\Donnees_CRTS\\irrisat_dessimination- smiej\\new.tif", ds, projWin = [681483.831264, 3558183.87652, 747933.831264,   3607833.87652]) ds = None   Have you any idea about what is happening right here?

Is it possible to use some gdal API to call gdal_translate from Python code? I do not mean simply executing the gdal_translate.exe from the file system, but rather call it somehow in code so I do not need to know the exact directory the gdal_translate executable is in?


Please give me a definition of . A textbook I have defines it to be - "A fundamental property of matter, which determines whether the matter will receive an electric flow or liberate one" I don't find this convincing enough. Any help would be appreciated.

Is there a definition of  and proper explanation of it?  It is said "Electric charge is the physical property of matter that causes it to experience a force when close to other electrically charged matter."  How is it though that matter can get charged?  Defining charge as the property of feeling a force with other charged matter seems circular.  What is charge?  Is there a non-circular definition / explanation?


In windows 7 you can start applications as admin by searching in the start menu and then pressing Ctrl+Shift+Enter.  Is a similar shortcut available for the Run Window (Win+R)?

Windows has this nifty little shortcut for running commands. Press Windows+r.  Problem is, is there an easy way to have the commands I run in that dialog to prompt for a UAC credentials dialog and get consent from a admin user.  Right now, I'm trying to run this command in the Run dialog runas /user:admin "regedit.exe"  It works when I run this though: runas /user:admin "cmd"


tag in itself does not make any sense.  It has no tag wiki, there are 439 questions tagged as blank and just 1 follower.  Should the tag be burniated?

Just found one question on SO with the tag . Got intrigued and went after explanation. Found empty wiki but used in 458 questions. Edit: 241 179 150 61 50 now.  0 to go!  Some tagged it because of , others relating to , others , etc  I feel this is a confusing and not helpful tag. Can someone clarify it so we can add a wiki to it, or should this tag be burninated?


How would you show that $n^3-n$ is divisible by $6$, when $n=k+1$ ?

As homework, I have to prove that     $\forall n \in \mathbb{N}: n^3-n$ is divisible by 6   I used induction  1) basis: $A(0): 0^3-0 = 6x$ , $x \in \mathbb{N}_0$ // the 6x states that the result is a multiple of 6, right?  2) requirement: $A(n):n^3-n=6x$  3) statement: $A(n+1): (n+1)^3-(n+1)=6x$  4) step: $n^3-n+(n+1)^3-n=6x+(n+1)^3-n$  So when I resolve that I do get the equation: $n^3-n=6x$ so the statement is true for $\forall n \in \mathbb{N}$  Did I do something wrong or is it that simple?


I know that may be trivial, but I don't know how to prove that if  $$w(\lambda)=(\lambda-\lambda_1)^{r1}\cdot \ldots \cdot (\lambda-\lambda_{k})^{r_k}$$ is a characteristic polynomial of matrix $A\in M_{n \times  n}(K)$ where $K=\mathbb{R} \ \vee \ K=\mathbb{C}$ then tr$(A)=r_{1}\lambda_1+_{\cdot \cdot \cdot}+r_k\lambda_k$ and that if $$(\forall \ k\in \left \{ 1,2,... \right \})  \ \text{tr}(A^k)=0$$ then $A$ is singular.  Any hints appreciated.

Let $A$ be an $n\times n$ complex nilpotent matrix. Then we know that because all eigenvalues of $A$ must be $0$, it follows that $\text{tr}(A^n)=0$ for all positive integers $n$.  What I would like to show is the converse, that is,      if $\text{tr}(A^n)=0$ for all positive integers $n$, then $A$ is nilpotent.   I tried to show that $0$ must be an eigenvalue of $A$, then try to show that all other eigenvalues must be equal to 0. However, I am stuck at the point where I need to show that $\det(A)=0$.  May I know of the approach to show that $A$ is nilpotent?


installed ubuntu-12.04.3 server. After installing, i could see only terminal mode login. I Dont see the GUI mode scree. How could i login to GUI mode login? If you need more details please let me know.

Trying to run a Ubuntu server for the first time... But everything is in a terminal. Is there a way to switch to a GUI?


I got a text that is written in German. I'm using \usepackage[utf8]{inputenc} since the text comes with the correct umlauts like ö, ä, ü and not "o, "a, "u. The output is pretty fine.   \documentclass[12pt,a4paper,ngerman]{article} \usepackage[utf8]{inputenc} \usepackage[ngerman]{babel}    %\input{glyphtounicode} %\pdfgentounicode=1  \parindent0pt  \begin{document} Viele Menschen sollten denken können, aber möchten es nicht. Dies ist ein Text den ich im PDF sehen möchte. \end{document}   But when I'm trying to copy text from the output (PDF) to Word, then I get the following:     Viele Menschen sollten denken k¨onnen, aber m¨ochten es nicht. Dies   ist ein Text den ich im PDF sehen m¨ochte.   Question: Any workaround here? The PDF text must support Copy&Paste. The glyphtounicode didn't help. Any idea?

Consider the following code:  \documentclass{article} \begin{document}    We define multiplication by    $$v_1x = 0,\quad v_2x = v_1,\quad v_1y = -v_1,\quad v_2y = v_1$$ \end{document}   which looks like this        It's as simple as it gets, but when I copy the content of the PDF I get:  We de??ne multiplication by v1x = 0; v2x = v1; v1y = ??v1; v2y = v1 1   So there are 4 errors:   The fi in define disappears  , becomes ; The minus sign is not being copied properly Another 1 appears at the very end of the copied text   How can I prevent this from happening? I use Texmaker with Miktex 2.9 and pdfLatex.


I purchased a flight from Brazil to Spain, with stopover in Morocco. My intention is to fly to Morocco and not take the second leg to Spain. I do not need a visa to Morocco but I need a Schengen Visa to enter Spain. Will I be allowed to board the first leg (Brazil->Morocco)?  Thanks.

Possible Duplicate:          I am in the process of booking a flight from LAX - ZUR. I found a flight for approx. 1100 USD. However, if I book that flight and then continue, after a 5 hour layover, onward to SVO, The flight is approx. half of the initial price, and the first leg of the second flight is the exact same flight as the first booking. Assuming I travel light and do not check any baggage, are there any potential issues with this? Seems like a hell of a way to save a good chunk of change.


I know that  states that the momentum and position of a quantum object can not be determined at the same time. This is very strange to me. I want the basic reason behind it, i.e why is this so.

$$\Delta x \Delta p_x \geq \frac{\hbar}{2} $$  I understand what does  states i.e. it's definition and it has been proven experimentally. But, can anyone please explain the reason for whatever this principle states i.e. why it happens?   Stating this principle in reference to the single slit experiment with electron (one particle experiment i.e. electrons are fired one at a time): Assuming the variable width of the slit is along the X-axis. So, if an electron passes through the a thin slit we can say the uncertainty in position is $=\Delta x$ which is equal to the  width of the slit. Now, we can also know the $x$ component of the momentum at he time when electron passes through the slit using distance between the slit and screen, time interval and the distance between the centre of the screen and the point where the electron hits.   As, the electron was fired towards the centre of screen we should expect a point on the screen but instead we get a gaussian distribution, and as we decrease the width of the slit (decrease $\Delta x$) the FWHM of the gaussian distribution increases i.e. $\Delta p_x$ increases which means the uncertainty in the measurement or prediction of $p_x$ increases.   Which is exactly what Heisenberg's Uncertainty principle states. But, can anyone please explain how/why this happens?


I am currently in the process of creating an iOS application, and I was wondering about capitalization of buttons and titles.   For example, should a button say "Add Post" or "Add post".  If I look at ux.stackexchange for example, I see buttons with the form "Ask Question" and "log in".

I am wondering if we should use  or  for buttons and headings in websites and web/mobile apps? Title Case: Manage my Account Delete my Account  Sentence case: Manage my account Delete my account  In  I found the recommendation 'choose your style and be consistent'. This is it? Aren't there any other (additional) recommendations or sources. Like for specific use cases or apps where the one style would be preferred over the other? Edit: The question refers primarily to English, but differences in other languages are also good to know.


Ref:  which does not address an adequate answer, and the question is lacking details.  I am in explorer view, and I drag and drop a new file into a folder. In versioning settings, I have "require check out" set to YES. None of my metadeta columns are set to "required."  After dragging/dropping, the file(s) are checked out to me.  I would like them to be checked in on initial upload, considering I have no metadata required to be entered.  Thank you.

I am uploading documents to a document library in SharePoint 2010 and I find my documents are checked out even they are not checked out. I have checked for option check out required to NO but even the problem doesn't go. Does anyone know the solution for this?


Let $B(0;1)=\{x \in \mathbb{R}^N;|x|≤1\}$, the ball of $\mathbb{R}^N$ equipped with the euclidian scalar product  $$x⋅y=x_1y_1+...+x_Ny_N,\ \ \ x=(x_1,...,x_N),\ \ \ y=(y_1,...,y_N)\ \ \ |x|=\sqrt{x \cdot x}$$ Let $\alpha$ and $\beta$ two real numbers, $\alpha \geq0$ , $a \in \partial B(0,1)$ fix.  $$h(x)=\log\left((1−x\cdot a)^{\alpha}+|x−a|^{\beta}\right)$$ Can we find $\alpha$ and $\beta$ such that $h$ is harmonic in $B(0,1)$?  ( harmonic signifies $\Delta_{x}h(x)=\displaystyle \sum_{i=0}^N \frac{\partial^2 h}{\partial x_i^2}$ ).

Let $B(0;1)=\{x\in \mathbb{R}^N ;|x|\leq 1\}$,  the ball of $\mathbb{R}^N$ equipped with the euclidian scalar product  $$x \cdot y=x_1y_1+...+x_Ny_N,\ \ \ x=(x_1,...,x_N),\ \ y=(y_1,...,y_N)\ \ \ |x|=\sqrt{x\cdot x}.$$ Let $\alpha\mbox{ , } \beta \mbox{ two real numbers, } \alpha\geq 0\mbox{ , } a \in \partial B(0,1)$ fix. $$h(x)=\log\left((1-x\cdot a)^{\alpha}+|x-a|^{\beta}\right)$$ Can we find $\alpha$ and $\beta$ such that $h$ is harmonic in $B(0,1)$?


I came across a comment online which mentioned that one of the main benefits of having 2 eyes is that we can perceive depth. I tried closing one eye and seeing for myself if somehow everything would appear to be at the same depth but it doesnt seem to be the case. I checked online and apparently it is true that having 2 eyes improves depth perception, but why? With our eyes being able to vary their focal length, we are  able to focus on objects up to our near point with even 1 eye, why does 2 improve depth perception and what does it have to do with the distance between the eyes?

I watched a video on  and read a few  which say that human beings see 3D because we have two eyes. But does that mean when I close one of my eyes, I should see 2D? It doesn't happen so. Why am i still able to be understand depth? Would a person with one eye not be able to perceive depths?


I have the following question:  If $f$ analytic on $\mathbb{D}$ with $|f'(z) - f'(0)| < |f'(0)|$, then $f$ is one-to-one.  I am not really sure what I should be using in this question. I have tried to use integral representations and power series expansions. However, I am not sure how this will help to show $f$ is one-to-one.

I am working on the following question:  If $f(z)$ is holomorphic on the unit disc with $|f'(z) - f'(0)| < |f'(0)|$ for all $z$ in the unit disc, then f is injective.  I've had several thoughts, but I don't really seem to be getting anywhere.  I defined a new function $g(z) = \frac{f(z)}{f'(0)} - z$.  Then $|g'(z)| < 1$.  I picked two distinct points, $z_1$ and $z_2$, took a path between them, and integrated $g'$ along a path between them.  But the best estimate I got from this was $|g(z_1) - g(z_2)| \le |z_1 - z_2|$.  If I has a strict equality, I can see how this would be enough to show that $f(z_1) \not = f(z_2)$, but I don't see how to make the inequality strict.  I thought about seeing if I could use the Schwarz lemma somehow instead, but I don't see how I would know that $g(0) = 0$ or $g'(0) = 0$, and even if I could so that I'm not sure that Schwarz would be useful here.    Any advice would be appreciated.


I have successfully created USB bootable stick using ubuntu 14.04.1 iso file.  But when I boot with this USB it asks about login info but won't accept any user name. Almost hanging !!!  What is the problem? What user name and password is supposed to enter? And how?   -- AVK

When I boot Ubuntu 10.04.3 from a live CD, it asks me to enter a username and password. I have not booted before, and I haven't created an account.


I'm getting ready for OCJP. and in one question they asked what this code will print: I thought this code would not compile. (I have never seen this syntax. I'm self taught). can someone please explain this code to me? and why does it print?  class Employee {    static int i = 10;  {       i = 15;       System.out.print(" Employee "+i);   }   static { System.out.print(" Employee static "+i); }     }  class Manager extends Employee {    static {     i = 45;     System.out.print(" Manager static ");   }{     i = 30;     System.out.print(" Manager "+i);   } }  class Owner extends Manager{   static { System.out.println("Owner"); } }  public class TestClass {       public static void main(String[] args) {       Manager m = new Manager();   }   the output:  Employee static 10 Manager static Employee 15 Manager 30

My question is about one particular usage of static keyword. It is possible to use static keyword to cover a code block within a class which does not belong to any function. For example following code compiles:  public class Test {     private static final int a;         static {         a = 5;         doSomething(a);     }     private static int doSomething(int x) {         return (x+5);     } }   If you remove the static keyword it complains because the variable a is final. However it is possible to remove both final and static keywords and make it compile.   It is confusing for me in both ways. How am I supposed to have a code section that does not belong to any method? How is it possible to invoke it? In general, what is the purpose of this usage? Or better, where can I find documentation about this?


Basically same question as above, if an ArrayList is passed to a constructor of an object, is it passed by reference or value?  In the example below, once I create the TickHistory object and pass an arraylist to it, if I later change the arraylist that I passed, will it also change in the TickHistory object instance?  public class TickHistory {     List<Tick> ticks;      String period;     String name;     Integer year;       public TickHistory(String name, String period, Integer year, List<Tick> ticks){         this.name=name;         this.period=period;         this.year=year;         this.ticks=ticks;     }  }

I always thought Java uses pass-by-reference. However, I've seen a couple of blog posts (for example, ) that claim that it isn't (the blog post says that Java uses pass-by-value). I don't think I understand the distinction they're making. What is the explanation?


I have some special chars declared that way.  private static readonly char[] Chars = "…".ToCharArray();   Also, I can check if that chars are present in given string like that way.  private static bool ContainsSpecialChars(string text)     {         return text.IndexOfAny(Chars) >= 0;     }   But I am stuck in counting how many occurencies are in the given string.  NOTE: I have array of chars

I am doing something where I realised I wanted to count how many /s I could find in a string, and then it struck me, that there were several ways to do it, but couldn't decide on what the best (or easiest) was.  At the moment I'm going with something like:  string source = "/once/upon/a/time/"; int count = source.Length - source.Replace("/", "").Length;   But I don't like it at all, any takers?  I don't really want to dig out RegEx for this, do I?  I know my string is going to have the term I'm searching for, so you can assume that...  Of course for strings where length > 1,  string haystack = "/once/upon/a/time"; string needle = "/"; int needleCount = ( haystack.Length - haystack.Replace(needle,"").Length ) / needle.Length;


Let's say that I have build a package using the typical method  ./configure make make install   and then I would like to uninstall this package. There is no any uninstall script. How can I revert my system back to the state it was before do the building/compiling ?

How do I remove a program that I have compiled from source using the ./configure; make; make install method?  Does it matter whether I have kept the original directory that the source was stored in or not?


This started occurring only in the last week or so. Only affects portrait layout, but it makes the menus completely unusable:

When I try to open my reputation notifications on the responsive design on my phone, I get this:    It's really thin, I can't see any of the items in there, and the links are off to the side. It happens at least on Literature.SE and Meta.SE.


I have the following priority_queue with items of type base. The problem is, when I get item from the Queue with top(), then call its f() function via base reference object, it does call the  f  of base class but not the overriden f.  I want child object's f() to be called. Any help? Thanks..      #include <queue>     #include <iostream>      using namespace std;      class base {          public:             int id;              virtual void f() const {                  cout << "base f()" << endl;             }      };      class D1: public base {          public:              void f() const {                  cout << "D1 f()" << endl;             }      };      class D2: public base {          public:              void f() const {                  cout << "D2 f()" << endl;             }      };      bool operator<(const base& b1, const base& b2)             {         return b1.id > b2.id;     }      int main()     {          priority_queue<base, deque<base>, less<deque<base>::value_type> > Q;          D1 d1;         D2 d2;          Q.push(d1);         Q.push(d2);  // this is not something  I want         const base& b = Q.top();         b.f();        // base f()   // this works as I want     const base& b2 = d2;     b2.f();        // D1 f()      return 0;      }

Someone mentioned it in the IRC as the slicing problem.


As we all know, if you want to make somebody aware of an response to a comment, you have to address them using @username if it's not their answer or question you're commenting in. (Sadly - Facebook style notification of all participants in a thread would be way better. But that's a different story.)  If you forget to do this, and edit your comment to add @username a short time later, will the user see the comment on their "recent" page? Or do you have to remove and rewrite the comment to trigger the notification?

I always wondered if users get notified about comments were their name was edited in afterwards.  Example:  I write a comment     See this link here   then I edit it to     @someuser: See this link here   Does the user get notified now?


In reviewing my document I found errors in capitalization of some acronyms in titles of references (dc or Dc instead of DC, etc). When I corrected the .bib file, changes were not reflected in the output. If I make more substantive changes (adding/removing words) they are reflected.  I am using BibTeX, MikTeX, and TeXstudio with:  \documentclass[conference]{IEEEtran}   to set up the document class.  And this call for building the bibliography:  \bibliographystyle{IEEEtran} \bibliography{ref}   Here's an example reference entry in ref.bib:  @article{patterson2012:green_building,   title={DC, come home: DC microgrids and the birth of the `enernet'},   author={Patterson, Brian T},   journal={IEEE Power and Energy Magazine},   volume={10},   number={6},   pages={60--69},   year={2012},   publisher={IEEE} }   And the output:    As others with similar problems attempted, I deleted all temp files (aux, bbl, blg, log, and gz) then compiled twice - but this didn't work.

Titles of articles I'm about to cite contain upper case letters and when using BibTeX it converts them to lower case ones. This happens only in the title and only the first letter conserves its case. For example, when I cite an article about HF, the reader won't know if it is about Hafnium (Hf) or fluorine acid (HF).  I know that I can fix it manually in the .bbl file but I would like to avoid it, or fix it automatically.


If given the unit circle, $x^{2}+y^{2}=1$, how does one go about showing it's a one-dimensional differentiable manifold?

Prove that the unit circle,  $$S^1:=\{(x,y)\in \mathbb{R}^2: x^2+y^2=1\}$$,  Is a one-dimensional manifold in $\mathbb{R}^2$ by using the following coordinate chars, known as stereographic projections, and completing the following steps.  a)Show that $U_N:=S^1$\ $\{(0,1)\}$ and $U_S:=S^{-1}$\ $\{(0,1)\}$ are open subsets of S^1. Here $(0,1)\in\mathbb{R}^2$ is the north pole of $S^1$ and $(0,-1)$ is the south pole.  b) Find an explicit formula for the function $\psi_S:=U_S\rightarrow\mathbb{R}$ that sends a point $(x,y)\in U_S$ to the horizontal coordinate obtained by the straight line that passes from the north pole through $(x,y)$ and intersectimg the line $y=-1$.  My attempt  a)  Let $\gamma_1:\{S^1-\{0,1\}\}\rightarrow \mathbb{R} \times \{0\}$ Be defined by: ?  Let $\gamma_2:\{S^1-\{0,-1\}\}\rightarrow \mathbb{R} \times \{0\}$ Be defined by: ?  Let $U\subset \mathbb{R}^2=\{S^1-\{0,1\}\}$  Let $V\subset \mathbb{R}^2=\{S^1-\{0,-1\}\}$  $U\cup V=S^1$ so for $c\in U\cup V=S^1$, $c\in U$ or $c\in V$. If $c\in U$ then $\gamma_1(U)=\mathbb{R}$ and likewise if $c\in V$ then $\gamma_2(V)=\mathbb{R}$, which are both open in $\mathbb{R} \times \{0\}$  If my attempt for part a is right, how should i define the functions and why?  b) If $\gamma_1$ and $\gamma_2$ are diffeomorphisms then we know $S^1$ is a smooth manifold of dimension $1$. Now we have to show that they are invertable.  Define $\phi_1:\mathbb{R}\rightarrow U$ by?  Define $\phi_2:\mathbb{R}\rightarrow V$ by?  As long as $\gamma_1$ and $\phi_1$ are inverses and $\gamma_2$ and $\phi_2$ are inverses, then we proved that the unit circle is a smooth manifold of dimension $1$.


Is the use of ordinal indicators with Roman numerals grammatical and if grammatical, is it unneeded? For instance: She is in VIIth standard. What about in case the ordinal indicator was written as a superscript?

Assume I have to use a Roman numeral to denote an ordinal number. Is it more correct to affix “-th” to it or not? That is, should I write “XIX century” or “XIXth century” to mean “nineteenth century”?


Where should I move the player and world files? My computer messed up and my profile isn't working, and my Terraria characters and worlds are all gone. I do have all the files but I'm not sure where to put them. I placed them to the same location in my new profile (windows profile) but when I lauched Terraria nothing was happened. Please help and sorry for language! :)

I want to transfer my world from my PC to a second PC, but I cannot find the world files.  Can you please help me?


I have this :    .themeMenu {   width: 100%;   height: 10%;   border: 0px;   overflow: hidden;   background-color: yellow; }  .Preview {   display: inline-block;   height: 100%;   width: 15%;   background-color: red;   margin-left: 2%; }  .mag {   display: inline-block;   height: 100%;   width: 15%;   background-color: green; }  .themeTitle {   display: inline-block;   height: 100%;   width: 20%;   background-color: green;   text-align: left; }

text here ruin it

     Problem : when I don't put text into themeTitle its aligned to the right just fine, but if I put one letter inside this div, all of it will go down so preview/mag are vertically aligned but themTitle goes down.   EDIT:  `vertical-align:top;`     will put the themeTitle in the same height with preview/mag, but the text will be on top, I need all of them to be vertically aligned to center :  ( preview | mag | themeTitle )

I have a div with two images and an h1. All of them need to be vertically aligned within the div, next to each other. One of the images needs to be absolute positioned within the div. What is the CSS needed for this to work on all common browsers?

testing...


I have previously asked question here but it was closed because I did not react fast enough twice already and I have put in the comments why those questions do not answer my problem. Nevertheless, my problem is still the same: I have a set of points (meteorological stations) with 5km buffers around them. Additionally, I have a set of polygons (municipalities) in which those stations are located. Each station buffer can be over 1,2,3... polygons and those can be completely different polygons.  I would like to have data on how much of the buffer is filled by each polygon but I was not able to find a function or a way to do it. So for example for point A I would have that in the buffer of 5km there is 80% of polygon B and 20% of polygon C as the output, so 4 values, two for IDs of the polygons and 2 for the percentage overlap (it could be only 2 values for other buffer or 6 etc. etc.).  Main difference to the other similar question provided is that I have 2 vector layers (Buffer with 500 buffers and Municipalities a shape file with 500 different polygons). Previous questions were analyzing this question in situations in which I know precisely the polygons and buffers analyzed, at least that is how I understood them, so after trying to use those approaches on my dataset I was not able to replicate them.  I have also commented on the approaches posted in the previous question but did not get any response to those sadly. Bottom line being I understand those approaches and was able to replicate them in a simple setting but when I do not have specific buffers/polygons I do not know how to execute them. Another way of approaching this problem was to use join attributes by location -one-to-many and then getting averages of the duplicate results, only problem is that then I take average of polygons instead of their weights corresponding to % of intersection with the buffer. In my case I do not know what polygons of the shapefile are going to intersect what buffers, or even if the buffer is going to be intersected by 1,2 or more polygons

I have a set of points (meteorological stations) with 5km buffers around them. Additionally, I have a set of polygons (municipalities) in which those stations are located.  I would like to have data on how much of the buffer is filled by each polygon but I was not able to find a function or a way to do it. So for example for point A I would have that in the buffer of 5km there is 80% of polygon B and 20% of polygon C as the output.  Edit:  The anwsers provided do anwser this question in a setting in which I know what polygons and buffers I need to have in the code or when I can do it manualy. Problem is that in my setting with 1 shapefile having 500 polygons and one vector layer having 13000 buffers I am unable to do this manually and I am asking if there is an easier way to do it. I tried implementing the approaches in the questions but I was unable to use them on my example in big scale. Moreover I had problems with coding that I also noted in comments down below.   Main difference to the other similar question provided is that I have 2 vector layers (Buffer with 500 buffers and Municipalities a shape file with 500 different polygons). Previous questions were analyzing this question in situations in which I know precisely the polygons and buffers analyzed, at least that is how I understood them, so after trying to use those approaches on my datasets I was not able to replicate them.  Another way of approaching this problem for me is to use join attributes by location -one-to-many and then getting averages of the duplicate results, only problem is that then I take average of polygons instead of their weights corresponding to % of intersection with the buffer. In my case I do not know what polygons of the shapefile are going to intersect what buffers, or even if the buffer is going to be intersected by 1,2 or more polygons


I am no JavaScript expert, but I found some code like this  a();  function a(){   alert('a'); }   and I was surprised to find it works (I think something like that will not work in Python). I expected that the function a can't be executed before being created. How does interpreter work and why functions can be called before declaration?

This code always works, even in different browsers:  function fooCheck() {   alert(internalFoo()); // We are using internalFoo() here...    return internalFoo(); // And here, even though it has not been defined...    function internalFoo() { return true; } //...until here! }  fooCheck();   I could not find a single reference to why it should work, though. I first saw this in John Resig's presentation note, but it was only mentioned. There's no explanation there or anywhere for that matter.  Could someone please enlighten me?


If you live in a two-dimensional world, would it be possible to explain the angular momentum?

In classical mechanics with 3 space dimensions the orbital angular momentum is defined as  $$\mathbf{L} = \mathbf{r} \times \mathbf{p}.$$  In relativistic mechanics we have the 4-vectors $x^{\mu}$ and $p^{\mu}$, but the cross product in only defined for 3 dimensions. So how to define orbital angular momentum e.g. in special relativity in terms of 4-vectors? Or more generally in $d$ dimensions?


Given three iid random variables, $X,Y,Z$  following a Uniform $(0,1)$ distribution. Then, how to find $\Pr(X>YZ)$?     Recently, I was asked this question in an interview, but I chocked there. Any hint will be appreciated.

$x,y,z$ are independent and uniform random on $[0,1]$.  I know that $P(x \geq yz) = 3/4$ by triple integrating the triple density function.  However, is there a easier way to get this solution? Without triple integration.


During the campus visit, I meet the faculty members, dean and provost individually and they asks me if I have questions to them. Actually, since I got all answers from the chair, I reply "no, I donot have questions". My question is what should I ask the dean, and provost, and other faculty members?

I will soon be at an on-campus interview for a tenure-track assistant professor position. I expect that in the course of the day, I will be asked the question, "Do you have any questions for us?" What are good questions for me to ask to show that I am interested in the department and would very much like to join?


In this film the ship has come back from apparently another dimension, are there any clues of where it might have been or what was there? I know there is mention Hell a few times but i was never sure throughout the film whether this was meant to be taken literally?

In the  movie, the crew figures out the ship has been to "Hell".  But I'm curious; does it go to Hell in a biblical sense, or does it visit something more akin to the universe the  (from ) come from?


Let $A,B$ be non-empty sets and $f:A\to B$ a function. Proof that $f$ is injective, iff $f\circ g=f\circ h$ implies that $g=h$ for all functions $g,h:Y\to A$, for every set $Y$?   I can see why this is. But how do I prove this? I get confused by the if and only if part.

Let $f: A \to B$ be a function. Prove that $f$ is one-to-one if and only if $f \circ h = f \circ k$ implies $h = k$, for every set $C$ and all choices of functions $h: C \to A$ and $k: C \to A$.  Here is my work:  Assume that $f$ is one-to-one and let $A = \{x_1, x_2\}$ for two arbitrary $x_1, x_2$. So we have $f(x_1) = f(x_1)$ and $x_1 = x_2$. Assume $h$ and $k$ are one-to-one. (Is that okay assume that they are one-to-one?) And let $C = \{z_1, z_2\}$ so we have $h(z_1)=h(z_2) = x_1$ and $k(z_1) = k(z_2) = x_2$ since $h: C \to A$ and $k: C \to A$.  If we substitute $h(z)$ and $k(z)$ into $x_1$ and $x_2$ respectively, we have $f(h(z)) = f(k(z))$. It follows $f \circ h = f \circ k$ implies $h = k$.  Conversely, we assume that $f \circ h = f \circ k$. It follows $f(h(z_1))=f(k(z_2))$ follows $z_1 = z_2$. Hence we can conclude that $h$ and $k$ are one-to-one. Since we know $h: C \to A$ and $k: C \to A$, ($x_1$ and $x_2$ are elements of $A$) and $h(z_1) = x_1$ and $h(z_2) = x_2$. Since $h(z_1)=k(z_2)$ implies $x_1 = x_2$ and since these two elements are in $A$, $f$ is onto.  I know it is hard to read, but I really need your help to check my ambiguous proof. I know some part are wrong, so please let me know. Thank you very much.


I'm unable to turn off a site's notification in windows 10, it keeps popping up now and then. It appears as  . I allowed this site to show me windows notifications when windows 10 asked me to do, but I can't see this app in "notifications and actions" settings, even when I turn off "Show app notifications" it keeps popping up. I tried to search for the site name in windows registry (HKEY_CURRENT_USER/SOFTWARE/microsoft/Windows/CurrentVersion/PushNotifications), no luck there too. I just can't figure out how to shut it.  Please any help would be greatly appreciated. Thanks in advance.

What should I do if my Windows computer seems to be infected with a virus or malware?  What are the symptoms of an infection? What should I do after noticing an infection? What can I do to get rid of it? how to prevent from infection by malware?   This question comes up frequently, and the suggested solutions are usually the same. This community wiki is an attempt to serve as the definitive, most comprehensive answer possible. Feel free to add your contributions via edits.


My local disks C & D and absolutely fine... But can I still access my data from the local disk E:... (And I did not format the disk) The size of the partition was also smaller than the size of the disk. It will be very very very helpful if I can still access that data...

I have two questions on ext4:   Is there currently a way to mount an ext4 partition in Windows (XP/Vista/7) to get basic read support? If not, are there any plans to support this someday?


Meaning like this, where there's a fixed width, and every line is scaled maintaining its aspect ratio to meet the width - including scaling the height (unlike regular justified text).   There might be tweaks to the tracking and kerning, but they're not the core feature of the style, which is the changing text size:      Woah! While finding examples I just noticed we have an almost-identical question already:       But those answers don't give a name for this style, they're just typographic terms, some of which may be used in creating this style, but none of which are this style.   Is there a name for this style, where the size (width and height) is adjusted to make each line equal in width and to bring out certain words?  It's not "justifying", because that doesn't involve changing the size of text, that only changes the letter spacing or occasionally width. It never changes the height. It's not "", which is setting type. 99% of the work of typesetters is not in this style.

You usually see this technique on infographics and brochures, and sometimes magazines:


I have recently started learning XML and very much confused about the use of elements and attributes. I have read many articles and some rules of thumb but still unable to get a clear picture of when to use what. For example one good rule of thumb is to use single valued data as attributes and multiple valued data as elements. Another to represent data as elements and meta data as attributes. Some articles say describe several other approaches or rules. I have several questions in mind and will much appreciate if any one can help me in understanding   What if the data is single valued ? Should I make it an attribute or an element. E.g. Marital Status of a person is single valued at the same time its data. What will be a difference in an attribute and element in such a case?  For example Date of birth is also a single valued data but many forums suggested making separate elements for day month and year and some suggested making a date of birth element and day year and month its attributes. What is the difference How will either approach help?  what is more useful for search operations and how ? If I want to design it in such a way that its more useful and efficient for searching what shall I do. For example what difference an element or an attribute of date of birth will make for a search operation I.e. if I want to search people born in 1980 or blah blah.

At work we are being asked to create XML files to pass data to another offline application that will then create a second XML file to pass back in order to update some of our data. During the process we have been discussing with the team of the other application about the structure of the XML file.   The sample I came up with is essentially something like:  <INVENTORY>    <ITEM serialNumber="something" location="something" barcode="something">       <TYPE modelNumber="something" vendor="something"/>     </ITEM> </INVENTORY>   The other team said that this was not industry standard and that attributes should only be used for meta data. They suggested:  <INVENTORY>    <ITEM>       <SERIALNUMBER>something</SERIALNUMBER>       <LOCATION>something</LOCATION>       <BARCODE>something</BARCODE>       <TYPE>          <MODELNUMBER>something</MODELNUMBER>          <VENDOR>something</VENDOR>       </TYPE>    </ITEM> </INVENTORY>   The reason I suggested the first is that the size of the file created is much smaller. There will be roughly 80000 items that will be in the file during transfer. Their suggestion in reality turns out to be three times larger than the one I suggested. I searched for the mysterious "Industry Standard" that was mentioned, but the closest I could find was that XML attributes should only be used for meta data, but said the debate was about what was actually meta data.  After the long winded explanation (sorry) how do you determine what is meta data, and when designing the structure of an XML document how should you decide when to use an attribute or an element?


In Java, class A defines a member variable private int num; Class B is a subclass of class A.   1- If the two classes are in the same package - does B inherit num?  2- If the two classes are not in the same package - does B inherit num?

In Java, are there clear rules on when to use each of access modifiers, namely the default (package private), public, protected and private, while making class and interface and dealing with inheritance?


i have a problem i want to change power button's location instead of right side i want it to be on left side is it possible i want to look it like mac please help me.  please if it is possible to change location of power button please help me

I downloaded a couple greeters for LightDM, but I have not figured out how to enable them. Is there a way to switch greeter, either by graphical or command-line method?. I do not intend to change display manager, nor the background, but to change the layout and appearance of the login screen through a different "theme" (greeter is the name for LightDm themes). Thanks for your time.


I am trying to write an excel file in a directory that the user will selected with a JFileChooser which is already working well.  My problem is that, when I am passing the path to a String:      private void JFileChooserExcActionPerformed(java.awt.event.ActionEvent evt) {                                                     JFileChooserExc.setCurrentDirectory(new java.io.File("."));     JFileChooserExc.setFileSelectionMode(JFileChooserExc.DIRECTORIES_ONLY);     JFileChooserExc.setAcceptAllFileFilterUsed(false);      if (JFileChooserExc.showOpenDialog(this) == JFileChooserExc.APPROVE_OPTION) {         try {             String path = JFileChooserExc.getSelectedFile().getAbsolutePath(); //Here is the problem             Rank(path);         } catch (IOException ex) {             Logger.getLogger(Principal.class.getName()).log(Level.SEVERE, null, ex);         }     } }   I receive the next exception:     "AWT-EventQueue-0" java.lang.NullPointerException   And the program broke.  I search for many websites and it looks like my code is fine. Any help with be appreciate.

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 deploy Java Swing application as windows software  I have tried the following to do this  I have created jar file for my project after that created exe file using Launch4j and Advanced installer, exe file produced by both softwares are working fine but those are placing the jar file inside that exe file, My problem is any one who has that exe file can extract and view the source code by decompiling java class file. Is there any way to deploy java application without decompiling the code, Please help me

How do I lock compiled Java classes to prevent decompilation?  I know this must be very well discussed topic on the Internet, but I could not come to any conclusion after referring them.  Many people do suggest obfuscator, but they just do renaming of classes, methods, and fields with tough-to-remember character sequences but what about sensitive constant values?  For example, you have developed the encryption and decryption component based on a password based encryption technique. Now in this case, any average Java person can use  to decompile the class file and easily retrieve the password value (defined as constant) as well as  and in turn can decrypt the data by writing small independent program!  Or should such sensitive components be built in native code (for example, VC++) and call them via ?


I am modeling a response Y against a predictor X, which is a product of two variables X1 and X2. I am interested in the coefficient of X.  Mathematically which way of modeling is correct?:   Y ~ X Y ~ X1 + X2 Y ~ X + X1 + X2   Thanks, maverik

Is it ever valid to include a two-way interaction in a model without including the main effects?  What if your hypothesis is only about the interaction, do you still need to include the main effects?


Using Ubuntu 16.04LTS printer stopped working. I think it was after an update.Will not give me a way to install the printer. the add button can not click it.If i try to continue it says no server.

My printer (hp oj250 mobile) requires hplip 3.16.8, but 3.16.3 is what I got when I installed hplip-gui on my freshly installed 16.04 box.  This is the response from the commands given in the comments to fix the dependencies:  $ sudo apt update&&sudo apt upgrade [sudo] password for user:  Hit:1 http://ppa.launchpad.net/deluge-team/ppa/ubuntu xenial InRelease          Hit:2 http://archive.ubuntu.com/ubuntu xenial InRelease                         Get:3 http://archive.ubuntu.com/ubuntu xenial-security InRelease [102 kB] Ign:4 http://www.openprinting.org/download/printdriver/debian lsb3.2 InRelease  Hit:5 http://www.openprinting.org/download/printdriver/debian lsb3.2 Release    Fetched 102 kB in 2s (46.4 kB/s)                               Reading package lists... Done Building dependency tree        Reading state information... Done All packages are up to date. W: http://www.openprinting.org/download/printdriver/debian/dists/lsb3.2/Release.gpg: Signature by key F8897B6F00075648E248B7EC24CBF5474CFD1E2F uses weak digest algorithm (SHA1) Reading package lists... Done Building dependency tree        Reading state information... Done Calculating upgrade... Done The following packages were automatically installed and are no longer required:   linux-headers-4.10.0-28 linux-headers-4.10.0-28-generic   linux-image-4.10.0-28-generic linux-image-extra-4.10.0-28-generic Use 'sudo apt autoremove' to remove them. 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.  $ sudo apt install -f Reading package lists... Done Building dependency tree        Reading state information... Done The following packages were automatically installed and are no longer required:   linux-headers-4.10.0-28 linux-headers-4.10.0-28-generic   linux-image-4.10.0-28-generic linux-image-extra-4.10.0-28-generic Use 'sudo apt autoremove' to remove them. 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.


How can I breed a shiny Charmander the easiest way in Pokemon x.  Your answers will be really appreciated because i'm desperate for a shiny Charmander in my game Pokemon x.  Thanks.

I remember seeing somewhere that if you breed a Pokemon from a different region its offspring would have a higher chance of being shiny. Is this true?  What other methods can be used to increase the odds of obtaining shiny Pokemon?  Also, What is the chance of breeding a shiny if one/both of the parent Pokemon are also shiny?


i want to compare two colums in and excel and write the result in the 3rd column.  input file is like this below   output file should be like this    This is wat i have done till now   import java.util.List; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.IOException;    import jxl.Cell; import jxl.Sheet; import jxl.Workbook; import org.openqa.selenium.By; import org.openqa.selenium.WebDriver; import org.openqa.selenium.WebElement; import org.openqa.selenium.firefox.FirefoxDriver; import org.testng.annotations.BeforeClass;  import java.io.FileInputStream;  import jxl.Cell; import jxl.Sheet; import jxl.Workbook; import jxl.format.Colour; import jxl.format.Pattern; import jxl.read.biff.BiffException; import jxl.write.Label; import jxl.write.WritableCellFormat; import jxl.write.WritableFont; import jxl.write.WritableSheet; import jxl.write.WritableWorkbook; import jxl.write.WriteException; import jxl.write.biff.RowsExceededException;  public class Test {      /**      * @param args      */ //variable declarations      String element;     static String storedElement[][]=null;     static String Element[][]=null;       public static void main(String[] args) throws BiffException, IOException, RowsExceededException, WriteException {         // TODO Auto-generated method stub          FileInputStream fs=new FileInputStream("file location(.xls)");           Workbook wb=Workbook.getWorkbook(fs);         Sheet sh=wb.getSheet(0);          Workbook workbook = Workbook.getWorkbook(new File("file location(.xls)"));         WritableWorkbook ww= Workbook.createWorkbook(new File("file location(.xls)RENAME THE FILE here "), workbook);         WritableSheet ws=ww.getSheet(0);          Label label;          //retrieving values from excel and storing in array         storedElement = new String[sh.getColumns()][sh.getRows()];         Element = new String[sh.getColumns()][sh.getRows()];         //for (int j = 0; j <sh.getColumns(); j++)          //{          int j=0; //column #0         int q=1; //column #1         //StringBuilder sb = new StringBuilder();         for (int i = 2; i < sh.getRows(); i++) //loop to run all rows          {             Cell cell = sh.getCell(j, i);             Cell cell1=sh.getCell(q,i);              storedElement[j][i] = cell.getContents();             Element[q][i]=cell1.getContents();             String elem =  storedElement[j][i];             System.out.println(elem);             String elem1= Element[q][i];             System.out.println(elem1);             String[] ob1=elem1.split("\n");             System.out.println(ob1[i]);             String[] ob = elem.split("\n");             System.out.println(ob[i]);           //for(int k=0;k<ob.length;k++){             int k=0;             while (k<ob.length){             if (ob[k]==ob1[k]){                     System.out.println(ob[k]);                     System.out.println(ob1[k]);                     label=new Label(2,i,"Valid");                 }                 else {                     System.out.println(ob[k]);                     System.out.println(ob1[k]);                     label=new Label(2,i,"InValid");                  }             k++;             //add new line ??                  ws.addCell(label);                 ww.write();                 ww.close();                 workbook.close();                   }         }      } }   i want to compare two columns in and excel and write the result in the 3rd column. here the cell contains two words where i need to write status for two words please help me in doing it

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


I want to chat with a user in a beta site () where I have over 100 reputation at the moment.  I recently lost some reputation by starting a discussion in the form of a question which was downvoted 3x; I want to avoid that in the future, but unfortunately now that I have identified a particular  with whom I want to chat, I cannot figure out how to even begin communicating with that person.

I've been looking around trying to find an answer to this question, but I haven't actually found a resource that gives a good answer. It continues to surprise me that chat is as separated as it is.  I ask because I can see the possibility for a couple good arguments as to why this should be the case, but they aren't immediately obvious to me. Still, I have to acknowledge the possibility that this configuration was intentional, since it seems too weird to be unintentional.  Is there a good reason why Stack Overflow chat is still on its network? If not, what is the historical reason/how did this come about?


I am trying to build a docker image with postgresql with Ubuntu. When the image is being built during the postgresql installation apt prompts for the config data (e.g. time zone settings), but the terminal emulator does not send a keypress for the apt's prompt. How do I either suppress this prompts or send some default values? Host OS: Windows 10 Dockerfile (meaning strings): FROM ubuntu:18.04 RUN apt-get update -y RUN apt-get install -y  python3-pip python-dev build-essential postgresql-server-dev-10 postgresql RUN pip3 install -r requirements.txt

I have the following line in the Dockerfile.  RUN apt-get install -y tzdata   When I run it, it asks for my input. After I provided my input, it hung there. Does anybody know how to solve this problem?  Step 25/25 : RUN apt-get install -y tzdata  ---> Running in ee47a1beff84 Reading package lists... Building dependency tree... Reading state information... The following NEW packages will be installed:   tzdata 0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded. Need to get 189 kB of archives. After this operation, 3104 kB of additional disk space will be used. Get:1 http://archive.ubuntu.com/ubuntu bionic-updates/main amd64 tzdata all 2018i-0ubuntu0.18.04 [189 kB] debconf: unable to initialize frontend: Dialog debconf: (TERM is not set, so the dialog frontend is not usable.) debconf: falling back to frontend: Readline debconf: unable to initialize frontend: Readline debconf: (This frontend requires a controlling tty.) debconf: falling back to frontend: Teletype dpkg-preconfigure: unable to re-open stdin:  Fetched 189 kB in 1s (219 kB/s) Selecting previously unselected package tzdata. (Reading database ... 25194 files and directories currently installed.) Preparing to unpack .../tzdata_2018i-0ubuntu0.18.04_all.deb ... Unpacking tzdata (2018i-0ubuntu0.18.04) ... Setting up tzdata (2018i-0ubuntu0.18.04) ... debconf: unable to initialize frontend: Dialog debconf: (TERM is not set, so the dialog frontend is not usable.) debconf: falling back to frontend: Readline Configuring tzdata ------------------  Please select the geographic area in which you live. Subsequent configuration questions will narrow this down by presenting a list of cities, representing the time zones in which they are located.    1. Africa      4. Australia  7. Atlantic  10. Pacific  13. Etc   2. America     5. Arctic     8. Europe    11. SystemV   3. Antarctica  6. Asia       9. Indian    12. US Geographic area: ``


$$\int^{ \pi /2}_{0} \ln (\sin x)\  dx$$  The answer is $- \frac{\pi}{2} \ln 2$.  I have changed it into $$\frac{1}{2} \int^{1}_{0} t d \ln t^{2}$$  But I didn't get the answer with it.

How to compute the following integral?  $$\int\log(\sin x)\,dx$$    Motivation: Since $\log(\sin x)'=\cot x$, the antiderivative $\int\log(\sin x)\,dx$ has the nice property $F''(x)=\cot x$. Can we find $F$ explicitly? Failing that, can we find the definite integral over one of intervals where $\log (\sin x)$ is defined?


I am writing this script: def main():     rc = RemoteControl()          # To Check if HCCU is responding to SCPI commands     scpi_command = r'*IDN?'     debug('Calling SendSCPICommandToHCCU:', scpi_command)     result = rc.SendSCPICommandToHCCU(scpi_command)     debug('Result:', result)      scpi_command = r'setup:ports:recall "SISO_NR"'     debug('Calling SendSCPICommandToHCCU:', scpi_command)     result = rc.SendSCPICommandToHCCU(scpi_command)     debug('Result:', result)  now in scpi_command I am passing a recall command to recall a profile which is a string("SISO_NR"). I want to modify this script in such a way that my script asks the user for the input of the string here. How can I do it?

How do I have a Python script that a) can accept user input and how do I make it b) read in arguments if run from the command line?


I tried to create a question before any I notice that was some possible bug here. Why i cannot use character "problem", but others can ? is this bug ? or any mistake make by me ?

Recently this Mathematica question was posted,  The reason for the odd split in the word pro-blem is there is a filter preventing its use in titles. For the most part, I can see where this is useful, as almost by definition all questions asked here are about problems. But, this filter prevents a legitimate use of the word that is accepted in the physics and math communities.   Is there a way around this, or is the problem so great that its legitimate use must be suppressed also?


I have a machine with both a SSD and a HDD in it.  I have two Windows installs one on the HDD and one on the SSD.  I've partitioned the SSD to have one OS in the majority of it and a small partition for swap on  in the remainder. The HDD has a different install of Windows.  For the Windows that is installed HDD I setup the swap to have swap files on both drives (HDD and small SSD partition).  When I look at prefermance monitor stats, it looks like the HDD swap is used before the SSD swap.  How can I tell Windows to use the secondary SDD swap file before the HDD one?

Suppose I have a 6 GB page file on an SSD and another 6 GB page file on a traditional mechanical 5400rpm SATA drive.  Does Windows take into account the difference in the performance characteristics between the two drives when deciding which page file to use?  If it matters, I'm asking about Windows 7 and higher.  I reviewed this  but it doesn't appear to factor in the case of dissimilar storage speeds.


I have an old laptop (Esprimo Mobile). I am new to Ubuntu. I ran xrandr -q and the only option available is 640 x 480  $ xrandr -q  xrandr: Failed to get size of gamma for output default  Screen 0: minimum 640 x 480, current 640 x 480, maximum 640 x 480 default connected primary 640x480+0+0 0mm x 0mm  640x480 73.00*  1240x800_60.00 (0x288) 80.750MHz -HSync +VSync  h: width 1240 start 1304 end 1432 total 1624 skew 0 clock 49.72KHz  v: height 800 start 803 end 813 total 831 clock 59.84Hz –    This makes my windows on screen way too big. How can I fix them?  EDIT: Since posting I have managed to create a new screen resolution option. When I applied the 1240 x 800 resolution it made things worse, all the windows became even wider and the top bar stretched out so I couldn't see the far right corner. I switched back from the 1240x800 (3:2) to the 640 x 480 but i am back where I started. What do I need to change?

I have 5-inch a 800x480 tft connected to the LVDS connector on a Portwell WADE-8020 mini-ITX embedded system board. I would like to build a XMBC/Kodi box for streming my music from my freenas PC with the tft showing what is been played, I got as fare as this...   sudo xrandr --newmode "800x480_60.00"  29.50  800 824 896 992  480 483 493 500 -hsync +vsync`enter code here   then,  sudo xrandr --addmode LVDS1 800x480_60.00   now that I get the correct resolution, I now have a black band on the top of the screen.  sudo xrandr --output LVDS1 --set "scaling mode"  "Full aspect"   However this did not solve the issue, also I know I need to amend the /bin/sh file with this from googling so I don't need to keep doing this at every boot. But I don't know how to as I'm very new to Linux.  #!/bin/sh xrandr --newmode "800x480_60.00"  29.50  800 824 896 992  480 483 493 500 -hsync +vsync xrandr --addmode LVDS1 800x480_60.00


I'm trying to get an arrow that has an arrow head pointing north east and south west, so like \updownarrow but rotated. I can't seem to find this in LaTeX at all. It has to go inside an equation environment.   Any ideas?

I know what my symbol or character looks like, but I don't know what the command is or which math alphabet it came from. How do I go about finding this out?


I dropped my phone in the ocean never got it back .can I recover any photos or contacts from it if I have ISDN ESN meid info

I lost my phone today and the data is turned off, but is there any way of tracking it even without the data? or getting my photos back?


It is said that $\frac{d}{dx}$ is a operator and $\frac{dy}{dx}$ is the derivative of y with respect to x. But now in thomas calculus he defined $\frac{dy}{dx}$ as the ratio of two quantities dy and dx,where dy and dx are differentials.     What is the difference between operator $\frac{d}{dx}$ and differentials?   How is a derivative is defined in terms of differentials? Please anyone help?

I ask because, as a first-year calculus student, I am running into the fact that I didn't quite get this down when understanding the derivative:  So, a derivative is the rate of change of a function with respect to changes in its variable, this much I get.  Thing is, definitions of 'differential' tend to be in the form of defining the derivative and calling the differential 'an infinitesimally small change in x', which is fine as far it goes, but then why bother even defining it formally outside of needing it for derivatives?  And THEN, the bloody differential starts showing up as a function in integrals, where it appears to be ignored part of the time, then functioning as a variable the rest.  Why do I say 'practical'? Because when I asked for an explanation from other mathematician parties, I got one involving the graph of the function and how, given a right-angle triangle, a derivative is one of the other angles, where the differential is the line opposite the angle.   I'm sure that explanation is correct as far it goes, but it doesn't tell me what the differential DOES, or why it's useful, which are the two facts I need in order to really understand it.  Any assistance?


Inside and outside of an open organ pipe usually medium used to be same (if i am not wrong) i.e Air, so in order to get standing wave reflection of wave is needed ( opp.in direction nd of same frequency). but how wave can get reflected at an open end without even changing medium?  none of my teachers able to answer it in a satisfied way.  Any help will be appericiated.

How can standing waves be produced in an open organ pipe even though both of its ends are open? Can someone explain with more clarity?


I noticed some real egregious reviewing on .  It was closed as a duplicate of a question that it doesn't come close to duplicating, the OP's problem being that of formatting Excel via C#, nothing to do with understanding floating-point calculations in a computer.  I was thinking that maybe there should be some facility to "flag"/"vote on" the reviewer and the specific review, by clicking on his name on that review and a dialog comes up, and ultimately building a rating for that reviewer based on commmunity input, that only the moderators could see.  Eventually, this might give them some data to correlate to bad reviews and they could implement a heuristic to use that.  For example, they could use it to influence the audits given a particular reviewer.  I'm sure with my contrarian views, I'd get tagged a lot, but I'm comfortable with the mods (as a group) reviewing the extreme cases and making decisions based on that.  As has been pointed out, it's a dupe of , so please go upvote it there.  <rant>It's sad that some users feel they need to use the downvote just because something is a dupe, instead of whether or not they disagree with the content, but that's life.  I'll make sure my voting is done correctly.</rant>

From what I've seen, many SO moderators trawl completed reviews and watch out for robo reviewers; and manual banning them when they see enough (>= 3?) bad reviews. This is inefficient because:   It doesn't integrate into the audit system. There's no "memory" to it. If mod A finds that user X has made two (any number less than the threshhold) bad reviews, he may make a mental note but there probably won't be any permanent/shared memory of this. If moderator B finds this user at a later date, he will have to look through the entire history, including stuff that mod A has already checked.    What I propose is that moderators get the ability to mark individual reviews as "invalid" from the completed review page. This is only to be used for reviews where any reviewer who is paying attention (and knows the rules) would choose the opposite reason (spam and other low quality stuff).   These bad review flags are treated like audits for a user -- if the number of failed audits and bad reviews is enough, the user gets autobanned. The nice thing is that this system should (probably) easily be able to , fixing the "Why was I manual banned?" problem.  This could also be integrated well with .


While studying machine learning I read about different sampling methods. Simple holdout, N-fold cross validation are straightforward. However, I somehow miss the point of bootstrapping. Its definition says that it's just a way to inflate the sample set simply by duplicating some random samples and I cannot figure what is the point in this -- seemingly no additional information in a learning process just by seeing the same instances again and again (on the contrary: others say that omitting redundant points from the training set is recommended for computational efficiency and for some other statistical reason as well). So what is the explanation here?

I recently used bootstrapping to estimate confidence intervals for a project. Someone who doesn't know much about statistics recently asked me to explain why bootstrapping works, i.e., why is it that resampling the same sample over and over gives good results. I realized that although I'd spent a lot of time understanding how to use it, I don't really understand why bootstrapping works.  Specifically: if we are resampling from our sample, how is it that we are learning something about the population rather than only about the sample? There seems to be a leap there which is somewhat counter-intuitive.  I have found a few answers to this question here which I half-understand. Particularly . I am a "consumer" of statistics, not a statistician, and I work with people who know much less about statistics than I do. So, can someone explain, with a minimum of references to theorems, etc., the basic reasoning behind the bootstrap? That is, if you had to explain it to your neighbor, what would you say?


So, our group (of which I'm the DM) was in a situation in which they wanted to drag each other during their turns (roughly an equivalent in increase of speed to the Dash action, as I pointed out) to escape a monster (well, a group of kobolds).    So, as to 'dragging' the others, they wanted to do something like grappling, but no skill checks or anything, just halving movement speed and dragging them. They took turns doing this and outpaced the kobolds, yep. I know that, RAW, this shouldn't be allowed, but I didn't see a problem realistically or within reason as per the rules? Might there be?

While DMing my session today, I encountered a situation I wasn't sure how to answer. The PCs were attacked by a werewolf and decided to flee onto their nearby horses. Two of them were already mounted and two of them were on foot. One player on the ground (a wizard) attempted to cast a spell on the werewolf and failed. He then moved closer to the mounts but couldn't make it with his speed. After a few turns it was the barbarian's turn. The barbarian wanted to drag the wizard with him and plop the wizard onto a horse and then mount with his remaining movement speed.  I wasn't sure quite how to handle it, so I made a compromise. I allowed the barbarian to drag the wizard. However, because the rules specifically state that it takes half of a character's movement to mount, I wouldn't allow the barbarian to force the wizard to mount. However, if the barbarian wanted to, he could mount the horse himself as he had enough remaining movement.  The reason I allowed the barbarian to drag the wizard is because of the lifting, dragging, and pushing rules in chapter 7 of the Player's Handbook. The barbarian had more than enough strength to push our tiny, lightweight wizard around.  I'm not really sure if I handled it right at all. I'm not entirely sure that those rules apply to living beings, especially living beings that can move. I would really appreciate some advice on whether or not players can drag other players after their (the player who is being dragged) turn is over or if players can drag other players at all. If I recall correctly, I believe the wizard still had about 5' of movement left, if it makes a difference.


I have been told that if we have a ring $R$ and $a$ is an element of $R$ and if we adjoin an element $b$ with the relation $b=a$ then we will get a ring isomorphic to $R$. However, I have not seen a formal proof for this. Is there a textbook or nice proof of this anyone knows of? I can't seem to see exactly how this is true.

I am doing a self-study using Artin's algebra. There is a problem which asks us to prove that adjoining an element to a ring doesn't do anything if that element was already in the ring.  More formally, say that $\alpha=a$ where $a\in R$. We want to show that $R\approx R[\alpha]$. (Where $\approx$ means "isomorphic to".)   My proof: We can consider $R[\alpha]\approx R[x]/(x-\alpha)$, which intuitively means "killing" $x-a$ in the ring of polynomials. Any function $f\in R[x]$ can be written as $(x-\alpha)g(x)+r(x)$ for some g,r by the division algorithm. Since the degree of r must be less than the degree of $x-a$, r must be a constant polynomial. Since $(x-\alpha)=0$, the residue of $f$ in $R[x]/(x-\alpha)$ is just r, which is some element of R. We can see that every $s\in R$ has a corresponding constant polynomial $f(x)=s$ in $R[x]$, which means the simple inclusion map $s\mapsto f(x)=s$ is our desired isomorphism.  So, this proof seems fine to me, except that I seem to have proven that adjoining any element keeps the ring the same. This sounds implausible to me. Where did I go wrong?


I'm trying to read a List of Strings and I keep having the following error:    with the following Parcelable class:  import java.util.List;  import android.os.Parcel; import android.os.Parcelable;  public class ActivePolicies implements Parcelable {      private List<String> activePolicies;      public ActivePolicies(List<String> activePolicies) {         this.activePolicies = activePolicies;     }      public List<String> getActivePolicies(){         return activePolicies;     }      @Override     public int describeContents() {         return 0;     }      @Override     public void writeToParcel(Parcel dest, int flags) {         dest.writeStringList(activePolicies);     }      public static final Parcelable.Creator<ActivePolicies> CREATOR = new Parcelable.Creator<ActivePolicies>() {         @Override         public ActivePolicies createFromParcel(Parcel in) {              try {                 return new ActivePolicies(in.createStringArrayList());             } catch (Exception e) {                 e.printStackTrace();                 return null;             }         }         @Override         public ActivePolicies[] newArray(int size) {             return new ActivePolicies[size];         }     };  }   It keeps giving me the exception on createFromParcel(), but I can't figure out why. It seems a simple parcelable, but when I'm debugging at readStringList() from the Parcel class, the list is null. But when I evaluate the value in createStringArrayList() before it's returning, the list is there with the expected values.

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 travel with L.H. from Paris-Frankfurt-Albania. It is one ticket with Lufthansa.  I should arrive in Frankfurt at 19.40 and the flight to Albania is at 20.40 I already booked my ticket and I am now in panic if I can make it. I will greatly appreciate your answer.  Thank you

I am traveling from Chennai to Atlanta. M first flight is to Frankfurt reaches at 8 30 AM. My second flight is scheduled at 10 45 AM.   Will the two hours transit time enough for boarding my second flight.  What should be my do's and dont's?  Update  Its more than enough. I was able to make it without any tension.


I have a class  class Class<T> {      public Class(T arg)      {          print(arg.ToString());      } }   Pls Correct me: How to create an instance from this generic class  Type t = typeof(Class<>).MakeGenericType(typeof(string)); Activator.CreateInstance(t,"test");

The title is kind of obscure. What I want to know is if this is possible:  string typeName = <read type name from somwhere>; Type myType = Type.GetType(typeName);  MyGenericClass<myType> myGenericClass = new MyGenericClass<myType>();   Obviously, MyGenericClass is described as:  public class MyGenericClass<T>   Right now, the compiler complains that 'The type or namespace 'myType' could not be found." There has got to be a way to do this.


How to determine the average rate of change of $f(x)= x^5-3x^4$ on the interval $[-2,4]$

Yeah, need help solving this one...  A function is given below. Determine the average rate of change of the function between x = 1 and x = 7.   g(x)= 3 + 1/2x


I have tried inputing the same int as the validPin variable, but it makes infinite loop even though  the condition is already true. Also, I have tried to change validPin to 12345 and it worked, but if the validPin is 002200 it doesnt work. Why? public void main() {      Scanner in = new Scanner(System.in);     int validPin = 002200;     System.out.print("Enter PIN to access:");     int pin = in.nextInt();       while (pin != validPin) {         System.out.print("Invalid PIN, Try again:");         pin = in.nextInt();     }      System.out.println("You have entered the correct PIN, now you have acces for your account!");  }  }

This prints 83  System.out.println(0123)   However this prints 123  System.out.println(123)   Why does it work that way?


I am trying to import a shapefile using db manager to postgresql. My shapefile has OBJECTID (PRIMARY KEY), ID (STRING FIELD eg: 2543-96-7948 )and several other attributes of type string. When importing I get the following error.  When I import using postgis shapefile import/export manager, I got no errors and the shapefile uploaded successfully. I think qgis is assuming my primary key to be ID field when it is actually OBJECTID. How to change this? I tried using the primary key field in input table and set it to id but got same error. Does it create new field or is it selecting a column from the attribute table? looked up for answers  but was not enough to resolve my issue.

I have a shapefile with a "id" field in which some non-unique ID numbers exist (don't ask).  When I try to import this to a PostGIS database using QGIS' DB Manager, it tries to re-use those IDs are unique primary key and fails.  The "Primary key" option is not ticked. "id" is shown in grey next to it.   How can I make DB Manager ignore an existing "id" column and just create a new SERIAL field or something like that?  QGIS 2.18.


I am trying to create an alias/bash script that will use apt to fully upgrade all applications on my computer as a background process.   But for some reason, later parts of the standard out appear to be printing to the main commandline, even if I spawn an entirely different bash instance and disown my script  bred@loaf:~$ alias aptup='sudo apt-get update > ~/aptlog && sudo apt-get dist-upgrade >> ~/aptlog && sudo apt-get upgrade >> ~/aptlog &' bred@loaf:~$ aptup [1] 24361 bred@loaf:~$ Starting pkgProblemResolver with broken count: 0 Starting 2 pkgProblemResolver with broken count: 0 Done Entering ResolveByKeep ^C [1]+  Done                    sudo apt-get update > ~/aptlog && sudo apt-get dist-upgrade >> ~/aptlog && sudo apt-get upgrade >> ~/aptlog    bred@loaf:~$ alias aptup="sudo bash -c 'apt-get update > ~/aptlog && apt-get dist-upgrade >> ~/aptlog && apt-get upgrade >> ~/aptlog & disown'" bred@loaf:~$ aptup bred@loaf:~$ Starting pkgProblemResolver with broken count: 0 Starting 2 pkgProblemResolver with broken count: 0 Done Entering ResolveByKeep ^C bred@loaf:~$    Note the "^C" is me using Ctrl+C to exit the process and regain control because the task is done.  EDIT: Also, I should be running the  --yes --force-yes   tags on each of the upgrade commands so that apt has permission to do upgrades if there are any. But the same result occurs nonetheless

For example, when I type ping 8.8.8.8 &, why can we see ping process working? And when I type find / -name '*test*' & , it's also seen on monitor.  Why is that? Is it not really in background?


A few years back, my parents gave me a Windows 8 laptop. After years and years of messing with the poor thing, I got it to a hardly working point, and it seemed Windows hardly even worked on it anymore. Because of this, I attempted to factory reset my laptop, just for the same weird errors and glitches to show up. Finally, I installed Ubuntu, and the errors stopped. After using the laptop for a year now, I still hardly know how to use Ubuntu, and I think that I should switch back to Windows 8 and attempt to fix it's problems. I was wondering if it is possible to get Windows 8 back on my Ubuntu for free? Thanks -Aiden

My friend borrowed my laptop for a while and when he gave it back he said he replaced Windows 7 with Ubuntu. I asked him to switch it back simply because I prefer Windows. He claims not to know how. I don't want to go buy a new windows 7 disc I just want to figure out how to get rid of this Ubuntu and Windows 7. If anyone knows a way please let me know...


I was trying to solve some exercise from my abstract algebra course, and at some point, I assumed $\mathbb{Z}/2\mathbb{Z} \cong \mathbb{Z}_2$ is an integral domain, because I thought to remember that $\mathbb{Z}_p$ is integral domain iif $p$ is a prime number. Am I right? If I am, how can I prove it to add it to my execise? If not, could you give me a counter example? Any help will be appreciated, thanks in advance.

I have already seen a proof of this statement here on stackexchange but I would like someone to verify whether "my proof" is correct and also if you could point out issues with the writing style. thanks in advance!  Statement. $\mathbb{Z}_{p}$ is an integral domain $\Leftrightarrow$ $p$ is prime.  Proof.$(\Rightarrow)$ Suppose $\mathbb{Z}_{p}$ is an integral domain. Assume (by way of contradiction) that $n$ is not prime. Then $n=ab$ for some $a,b\in \mathbb{Z}$ where $1<a$ and $b<n$, meaning $ab\equiv 0\pmod n$. This is a contradiction since $\mathbb{Z}_{p}$ is assumed to be an integral domain and therefore does not contain any zero divisors. Therefore $p$ must be prime.  $(\Leftarrow)$ Assume $p$ is prime. Then $a$ does not divide $n$ for any $1<a<n$ where $a\in \mathbb{Z}_{p}$. Thus $\mathbb{Z}_{p}$ does not contain any zero divisors and is therefore an integral domain.


I am having cron run a shell script which includes this line...  /etc/init.d/nginx reload   but it is giving me an exit code of 2...What can I do to reload nginx from cron successfully?

I created 3 daily cron jobs to run.  Below are the three that are placed in etc/cron.daily  rkhunter.sh  #!/bin/sh ( rkhunter --versioncheck rkhunter --update rkhunter --cronjob --report-warnings-only ) | mail -s 'rkhunter Daily Run (my server)' me@email.com   chkrootkit.sh  #!/bin/bash chkrootkit | mail -s "chkrootkit Daily Run (my server)" me@email.com   logwatch.sh  #!/bin/sh ( logwatch ) | mail -s 'logwatch Daily Log (my server)' me@email.com   I replaced me@email.com ofcourse with my email.  If I run this cronjob manually it works fine ./nameoffile.sh  But it doesn't run daily, what can be the cause or how can I check into this?


I have reviewed a rather large number of SO posts, but I'm still very puzzled about the suggested sites on the migration list.  For example, why are  and  present but  and  are not even when quite a few questions on Stack Overflow are iOS or Android specific.  Recently  was replaced by . How come?

Currently, there is a 40% (updated Nov 9, 2012) rejection rate on migrations from Stack Overflow to Server Fault.  Here are some samples of rejected questions from the last few days:   .     The first example is from 2009 and already had an accepted answer (in addition to being bad and off-topic on SF). There was no reason to migrate it. The second two, while seemingly on-topic for SF based on the title, are borderline unintelligible in regards to the content. They contained no details, no relevant information, and amount to "Halp! Halp! Itz broked!"  I realize that there is a much larger number of users on Stack Overflow that are capable of voting to migrate and as a result, it takes 4/5 votes to migrate, while every other site is 3/5. This, unfortunately, does not appear to be an effective solution.  Questions should not be migrated based on their title, they should be judged on their content and topicality on the target site. This, obviously, is not happening as there is a 40% rejection rate on Server Fault.  What can we do to further educate Stack Overflow users about what is and is not on-topic elsewhere? Should SO have a higher reputation threshold than the other sites for vote-to-migrate privs? Should a migration require 5/5 votes instead of the current 4/5?


Is there a way to set the data of the clipboard as html instead of plain text ? I know this is easely done in C# with :  Clipboard.SetData(DataFormats.Rtf, (Object)temp);   But i'm looking for a javascript solution ( can include jquery etc ... )  Edit: this only needs to work for Internet Explorer

What is the best way to copy text to the clipboard (multi-browser)? I have tried: function copyToClipboard(text) {     if (window.clipboardData) { // Internet Explorer         window.clipboardData.setData("Text", text);     } else {         unsafeWindow.netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");         const clipboardHelper = Components.classes["@mozilla.org/widget/clipboardhelper;1"].getService(Components.interfaces.nsIClipboardHelper);         clipboardHelper.copyString(text);     } }  But in Internet Explorer it gives a syntax error. In Firefox, it says unsafeWindow is not defined. A nice trick without using :


I have been using Teamviewer to connect my Windows machine from ubuntu for the past three months. Now I'm facing an inconvenience to use Teamviewer.   I'm using team viewer to connect remote desktop of windows. I don't have any dedicated IP and my modem doesn't support any free DDNS services so I'm not able to use inbuilt remote desktop connection feature in windows.  Does anybody can suggest me a good alternate program to use in Ubuntu 12.04?

Is there any Ubuntu alternative for team-viewer software for Windows?


I just got an HP laptop with a Realtek RTL8821CE  802.11ac network controller. Ubuntu studio 20.04 LTS works fine except for the Wifi. sudo lshw -C network shows the hardware but lists it as *-network UNCLAIMED Secure boot is disabled. How can I get the drivers for this and install them? My internet access is limited to Windows10 Wifi at this time.

I'm trying to install drivers for my Wifi on my HP All-in-one desktop. I've been told to show the output of the command "sudo lshw -C network" so here it is:  *-network description: Ethernet interface product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller vendor: Realtek Semiconductor Co., Ltd physical id: 0 bus info: pci@0000:01:00.0 logical name: enp1s0 version: 15 serial: 48:ba:4e:5c:06:5f size: 100Mbit/s capacity: 1Gbit/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full firmware=rtl8168h-2_0.0.2 02/26/15 ip=192.168.1.21 latency=0 link=yes multicast=yes port=MII speed=100Mbit/s resources: ire:31 import:e000(size=256) memory: fea04000-fea04fff memory:fea00000-fea03fff  *-network UNCLAIMED description: Network controller product: Realtek Semiconductor Co., Ltd. vendor: Realtek Semiconductor Co., Ltd. physical id: 0 bus info: pci@0000:02:00.0 version: 00 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress cap_list configuration: latency=0 resources: import:d000(size=256) memory:fe900000-fe90ffff   Output from "lspci -nnk | grep -A2 0280":  02:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8821CE 802.11ac PCIe Wireless Network Adapter [10ec:c821] Subsystem: Hewlett-Packard Company RTL8821CE 802.11ac PCIe Wireless Network Adapter [103c:831a] 03:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS5229 PCI Express Card Reader [10ec:5229] (rev 01)


I want to achieve the following: Whatever number may be printed to the console, it has to have 2 digits after the decimal mark. When the result is a decimal number, the program rounds it off to 2 digits after the decimal mark, so this is fine. The problem is, however, that whole numbers don't get .00 attached to them, i.e. 100 gets printed as 100, and not as 100.00 as I want it to. I've been struggling with this for quite a while so I any help will be highly appreciated.  using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;  namespace TorrentPirate {     class Program     {         static void Main(string[] args)         {                 int megabytes = int.Parse(Console.ReadLine());                    int cinemaPricePerMovie = int.Parse(Console.ReadLine());                 int wifeSpendingHour = int.Parse(Console.ReadLine());            TimeSpan time = TimeSpan.FromSeconds(megabytes/2);            double downloadTime = time.TotalHours;            double downloadPrice = wifeSpendingHour * downloadTime;            int NumberOfMoviesDownloaded = megabytes / 1500;            double cinemaPrice = NumberOfMoviesDownloaded * cinemaPricePerMovie;              if (cinemaPrice >= downloadPrice)             {                 downloadPrice = Math.Round(downloadPrice, 2);                 Console.WriteLine("{0} -> {1}lv", "mall", Convert.ToDecimal(downloadPrice));                     }             else             {                 cinemaPrice = Math.Round(cinemaPrice, 2);                 Console.WriteLine("{0} -> {1}lv", "cinema", Convert.ToDecimal(cinemaPrice));             }          }     } }

When displaying the value of a decimal currently with .ToString(), it's accurate to like 15 decimal places, and since I'm using it to represent dollars and cents, I only want the output to be 2 decimal places.   Do I use a variation of .ToString() for this?


When I was young, the possessive form of the word, it, required an apostrophe preceded by an S. An example our teacher used, which I've always remembered, was: "It's my work but I am its' property, rather than the reverse, by virtue of how essential the work has become."    Over several years, however,  I've seen the trailing apostrophe almost totally removed from usage.  When and why did that rule change?

I just had a strange flashback to a conversation I had when I was in high school, with a man who was regarded by many members of a particular online community as having an impressive degree of knowledge of the English language.  The conversation centered on a claim this man made that I found very difficult to accept. I had made some remark involving the difference between it's and its (a distinction which I trust is quite well-known to the majority of users on this site), to which he had contributed, mostly phrased as an amusing aside, that there was one more word I hadn't mentioned: its', with the apostrophe at the end.  I originally thought he might have been joking, but we ended up debating this rather fervently. I seem to recall that I kept demanding he use the word in an example sentence, but he either could not or refused to do so. Yet he maintained that it is a word.  Is this true? I must concede I haven't put a lot of thought into it just now; but at the time, I was perplexed by the very suggestion that it could be a word (what could it mean?), and at the moment I can't really think of any scenario where it would make any sense.


Ubuntu 17.10,GNOME in Xorg. My terminal application icons are partially blocked out.     This is true in Wayland, Xorg and Classic, all shell themes, all icon themes and all application themes. Annoying and at a loss as to what to do to fix it.

A while ago I upgraded from Ubuntu 17.04 to Ubuntu 17.10 and everything is working fine except for the fact that the icon in the window title bar of my Terminal seems to be stretched out to some ridiculous size.    This only seems to happen in the Terminal window. The Nautilus icon is completely fine.    The problem seems to go away if I login into an Xorg session instead of a Wayland one. I've looked around and didn't find any immediate solution to this. Any help would be greatly appreciated.


I'm currently a teacher's assistant in a web development course. Today, a student asked for help with his homework, in which he'd used setInterval, passing as the first parameter a function which he didn't define until a few lines of code later. I told him that wouldn't work, as the function would be undefined by the time the interval setting code was reached.  To my surprise, it worked perfectly. I've been trying to research this and am coming up blank: does JavaScript actually wait until the first execution of the callback to even see if the function name passed to it exists? That seems so counter-intuitive, but I can't imagine any other reason it would have worked. Where can I find out more about this unexpected behavior?

This code always works, even in different browsers:  function fooCheck() {   alert(internalFoo()); // We are using internalFoo() here...    return internalFoo(); // And here, even though it has not been defined...    function internalFoo() { return true; } //...until here! }  fooCheck();   I could not find a single reference to why it should work, though. I first saw this in John Resig's presentation note, but it was only mentioned. There's no explanation there or anywhere for that matter.  Could someone please enlighten me?