I'm trying to draw parse trees for mathematical expressions such as (x + (y - z)).  When I google for parse trees in LaTeX, all I get are packages that produce an output similar to the style of :    However, the notation used at my university doesn't resemble that at all. Our parse trees look like this:    Or like this (using a slightly different notation that doesn't show the intermediate nodes):    I'm stuck for what to do. Are there any packages that will produce this kind of output that I haven't come across?

So, I want to typeset some proof trees, i.e. trees of inference rules like those in natural deduction (see diagram below). Which are the best packages that you have found that allow you to do this, and which features do they have?


Perhaps, that's a very easy question - I wonder what's the code of the symbol that looks like the square bracket [ but whose vertical line is double, like in || represented by $\|$.

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?


Let $R$ be a commutative ring with unity such that $R[X]$ is a UFD. Denote the ideal $\langle X\rangle $ by $I$.  Prove that    If $I$ is maximal, then $R[X]$ is a PID. If $R[X]$ is a Euclidean Domain then $I$ is maximal. If $R[X]$ is a PID then it is a ED.   We know that $R[X]/\langle X\rangle \cong R$. Since $I$ is maximal then $R$ is a field. Also every field is a Euclidean Domain and hence a PID and also a UFD.  By Gauss Lemma $R[X]$ is a UFD.  But these facts are not helping anything in these statements to prove.  Please give some hints.

I've just read a proof of the statement:  Let $R$ be a commutative ring. If $R[X]$ is a principal ideal domain, then $R$ is a field.  In one part of the proof there is a step which I don't understand. I'll copy the proof: Let $u\in R$ be non-zero. Then using the principal ideal property, for some $f\in R[X]$ we have $\langle u,X\rangle = \langle f \rangle \subseteq R[X]$. Therefore, for some $p,q∈R[X], u=fp$ and $X=fq$. By properties of degree we conclude that $f=a$ and $q=b+cX$ for some $a,b,c\in R$. Substituting into the equation $X=fq$ we obtain $X=ab+acX$ which implies that $ac=1$, i.e. $a\in R^\times$, the group of units of $R$. Therefore, $\langle f\rangle =\langle 1\rangle=R[X]$. Therefore, there exist $r,s\in R[X]$ such that $ru+sX=1$ and if $d$ is the constant term of $r$, then we have $ud=1$. Therefore $u\in R^\times$. Our choice of $u$ was arbitrary, so this shows that $R^{\times}⊇R \setminus \{0\}$, which says precisely that $R$ is a field. I don't understand this: "$X=ab+acX$ which implies that $ac=1$, i.e. $a\in R^\times$, the group of units of $R$. Therefore, $\langle f\rangle = \langle 1\rangle =R[X]$." Why does the fact that $a=f$ is a unit implies that $\langle f\rangle = \langle 1\rangle$? I would appreciate if someone could explain this to me. Thanks in advance.


Recently, I saw  video, showing the phenomenon of the self-siphoning beads.  Dangling one end of a coiled string of beads outside of the container, a single pull is needed to cause all the beads to fall out.  Why is this so?  My main question: It is also observed that the longer and more coiled the string of beads is, the higher the exiting beads will "jump".  Why?  This not only defies the principle of gravity that I learnt, but also the fact that energy cannot be created!

There is a  being thrown out of a flask, literally hovering out of the container  My question is how detailed a physical explanation of this phenomenon we have?  Question: More precisely, if we used the best available mechanical physics simulator software, and we tried to simulate this behavior, would the software be able to reproduce the effect or not? My guess is not but I would like to know why not.  Or do we have to content ourselves only with handwaved explanations? I am from the school of thought that you don't understand physics until you have a reasonable certainty that you can reproduce the physics in a computer.


A PI I might potentially apply to is planning on making three or so offers. Said PI only has a few students at present which I think is the reason for their doing so.  I worry that I will not get my hands on very many projects and will not have enough time with the PI. So my question is: How detrimental is a large lab cohort to a graduate students’ success?  I think it is important to mention that this is a social-sciences PhD program with cohorts of around ten or fewer. This situation seems unique as the PI needs students this year. Most labs only take one student per year.

I have chosen to work under a associate professor as my PhD advisor. He has a small research group -a group of 3 graduate students and some Undergraduates. I see colleagues of my advisor have groups of 10-12 students with 3 postdocs.   Am I missing something- research wise ??


CREATE TABLE logistics (     id int auto_increment primary key,     campaign VARCHAR(255),     process_status VARCHAR(255),     delivery_type VARCHAR(255),     quantity INT );  INSERT INTO logistics (campaign, process_status, delivery_type, quantity ) VALUES  ("C001", "offer", "fedex", "500"), ("C001", "offer", "fedex", "200"), ("C001", "order", "ubs", "400"), ("C001", "shipped", "ubs", "100"),  ("C002", "offer", "fedex", "800"), ("C002", "offer", "fedex", "100"), ("C002", "order", "fedex", "650"), ("C002", "shipped", "fedex", "250"),  ("C003", "offer", "fedex", "730"), ("C003", "order", "fedex", "620"), ("C003", "shipped", "dhl", "530"),  ("C004", "order", "fedex", "200"), ("C004", "shipped", "fedex", "130"),  ("C005", "order", "fedex", "900"), ("C005", "shipped", "ubs", "475"),  ("C006", "order", "fedex", "635");   Expected Result  campaign      process_status       delivery_type      quantity C001          offer                fedex              700 C001          order                ubs                400 C001          shipped              ubs                100 C003          offer                fedex              730 C003          order                fedex              620         C003          shipped              dhl                530 C005          offer                fedex              900 C005          shipped              ubs                475     In the above table I have different campaigns, their process_status and delivery_type.  Now, I want to extract all campaigns which switch their delivery_type between different process_status.   Therefore, I am looking for a query that does something like this:  SELECT campaign, process_status, delivery_type, quantity FROM logistics WHERE delivery_type differes in different process_status   I have no clue how the WHERE condition must look to achieve the expected result.  Do you have any idea?

This is a very basic query I can't figure out....  Let's say I have a two column table like this:  userid  |  roleid --------|--------    1    |    1    1    |    2    1    |    3    2    |    1   I want to get all distinct userids that have roleids 1, 2 AND 3.  Using the above example, the only result I want returned is userid 1.  How do I do this?


I want to recursively rename files and directories from the current directory. The characters < > : " \ | ? * / should be removed. Also remove the spaces at the start and end of a filename. This is what I have so far, it's giving me trouble with the / of the subdirectories:  find . -depth -exec rename -n 's![:<>/"\\|?*]!!g; s/ *$//g' {} \;   Edit: The trouble that it gives me with / is that it's replacing the forward slash separating directories and introducing the subdirectory into the name of the file. So according to  it should be something like this:  LC_ALL=C find . -depth -execdir rename -n 's![:<>/"\\|?*]!!g; s/( *$)//g' {} +   Now it gives me a problem with filenames with newlines, it thinks each line is a different file and it's trying to rename files that don't exist. Also the rename should only execute for files that present problems in the filenames, so use the -name flag for find. It also needs to remove the spaces at the start. I need some explanation on each part of the command used in the answer. I don't even remember why I have copied the LC_ALL=C.  Maybe this fixes the problems, I still have to try it:  LC_ALL=C find . -depth -exec rename -n 's![:<>/"\\|?*]!!g; s/\n/ /g; s/ *$//g; s/^ *//g;' {} \;   The context is that I had to do chkdsk /f e: to fix a hard drive that couldn't mount on Linux Mint. chkdsk fixed the problem but it moved and renamed every file with special characters. So now I had to move and rename again those files as they were before but without special characters. I want to have a way to avoid all that, by running a command to fix the names from time to time so I don't run into the same problem again. That's why I asked this question.

I'm looking to write a script that will find and replace any characters other than [^A-Za-z0-9._-] in a specific file type (in this case .avi) with an underscore _. I want this to exec recursively from the current path. I'm using Ubuntu.  I do not want or need to change any folder names as I have control over those at the time of creation. Here's what I have now after referencing the following link:    find . -depth -exec rename 's!([^/]*\Z)/[^A-Za-z0-9._-]/_/g' *.avi {} +   I'm clearly missing something. Please help. :)


I really liked following diagram from Wikipedia which shows how different graphical components are connected to each other.:    As per my understanding, here 1) "graphical interface" is closely related to what we know as "Desktop Environment" as KDE, GNOME etc. are given examples. 2) X11 etc. are "windowing systems" 3) Xorg, Mutter etc. are listed as display servers and 4) Compiz etc. are window managers A normal users or those who are new to GNU/Linux would probably know only about Desktop Environment, not about rest of components. I want to know which of each components are running on my system. So, How do I know which Windowing system, which display server and which display server I am using on my GNU/Linux system? (preferably through command line)

I was wondering what commands/utilities can be used in terminal to know the types of  (such as X window system),  (such as Metacity, KWin, Window Maker) and  (such as KDE, Gnome) of a Linux or other Unix-like operating systems?  Thanks!


Question seems to be basic but I am not sure, but to the point. I have three vectors:  std::vector<int> vect1; std::vector<int> vect2; std::vector<int> vect3;   And for example vect1 has 3 members (10, 20 and 30), and vect2 has also 3 members with some other values like 15, 25 and 35. And I would like to push back all values of vect1 into vect3, and then push back all values of vect2 into vect3, so vect3 would have 6 members in order: 10, 20, 30, 15, 25, 35.  I know I can do that with for loop, but I wonder if I have thousands of members like in audio processing (eg. 44100) and each member would have some complex calculation, wouldn't be more CPU saving if I would make some simple steps? I imagine something like:  vect3 = vect1 + vect2;   or  vect3.push_back ...; // and here in some way all values of vect1  vect3.push_back ...; // and here in some way all values of vect2   Maybe it's stupid, because even if there is some simple function like that, I suppose looping would be going somewhere under the ground in std::vector definition. But I just wonder out of curiosity.  At all I was always wondering about some basics things about loops, how much time is consumed by each single step of some basic loop, for example:  int a=0; for (int i=1; i<=100; i++) {    a = i; }   So I can calculate how much time is consumed by execute whole loop. Is there any way I can check it? And other stupid questions, for example, does it matter for CPU load if I create variables outside (before) the loop, like here:  int a; int b; int c; for (int i=0; i<100; i++) {     a = i * 2;     b = i * 3;     c = a + b; }   Or maybe better would be like that:  int c; for (int i=0; i<100; i++) {     int a = i * 2;     int b = i * 3;     c = a + b; }   Where to find answer for such questions?


I'm using Ubuntu 14.04 and these key combinations do not work. If I toggle NumLock then Home and End without Shift don't work properly. I found some proposed solutions for older versions of Ubuntu but they refer to menu settings that no longer seem to exist.

I am used to use the numeric keypad for navigation (e.g. : [KP7] -> Start, [KP1] -> End, [KP4] -> Left, etc... ). I am also used to use it for selection (e.g. : Shift+[KP7] -> Select from cursor position to beginning of line, Shift+[KP1] -> Select from cursor position to end of line, etc...)  With the keyboard configuration installed with Ubuntu, though, Shift+[KP7] prints the character "7", Shift+[KP1] prints "1", etc...  How can I change this so that Shift+[KP-key] is not mapped to [key], but to Shift+[KP-key] ?


From Royden's Analysis book (4th Edition) Chapter 5 Section 2 Problem 7:     Let $E$ have finite measure, $\{f_n\}\rightarrow f$ in measure on $E$ and $g$ be a measurable function on $E$ that is finite a.e. on $E$. Prove that $\{f_n \cdot g\} \rightarrow f\cdot g$ in measure.   I've attempted many different approaches, but to no avail. If anyone could give a starting hint (not necessarily a solution), I would be extremely grateful.

Let $E$ be of finite measure, $f_n \rightarrow f$ in measure and $g$ be measurable and finite a.e. Prove that $f_ng \rightarrow  fg$ in measure   My attempt : We have $g$ is finite a.e thus $D:= \lbrace x : \vert g(x) \vert = \infty\rbrace$ then $\mu D =0$ Now as $f_n$ converges in measure we have following for any $\epsilon$  $E':= \lbrace x : \vert f_n(x)-f(x) \vert \geq \epsilon \rbrace$ then $\mu E\rightarrow 0$ and $n \rightarrow 0$  Now,  For any $\epsilon > 0$  $E_0 := \lbrace x : \vert f_n(x)g(x)-f(x)g(x) \vert \geq \epsilon \rbrace =  \lbrace x : \vert g(x)\vert \vert f_n(x)-f(x) \vert \geq \epsilon \rbrace \cup D$  but measure of both the sets on RHS is $0$ as $n \rightarrow \infty$ thus  $\mu E_0 \rightarrow 0$ and $n \rightarrow 0$  I am not sure if the equation of union of sets which i am trying to formulate is right.


I want to write a MPM graph for my students. For the moment, here is a short example of what I can do :  \begin{tikzpicture}   \node[draw,black] (A) at (0,1) {     \begin{tabular}{|c|c|}       \hline       \textbf{A} & (2) \\       \hline       \textcolor{blue}{0} & \textcolor{red}{5} \\       \hline       \textcolor{green}{5} & \textcolor{purple}{0} \\       \hline     \end{tabular}   };   \node[draw,black] (B) at (3,1) {     \begin{tabular}{|c|c|}       \hline       \textbf{B} & (4) \\       \hline       \textcolor{blue}{2} & \textcolor{red}{7} \\       \hline       \textcolor{green}{5} & \textcolor{purple}{0} \\       \hline     \end{tabular}   };   \draw[->,>=latex,black,very thick] (A.east) -- (B.west); \end{tikzpicture}   The problem is the following : if I don't use the "draw" option in defining the nodes, the arrows are not pointing at the right places. But if I use "draw", then I have an ugly rectangle around my tabular.  Is there a way that I can combine the best of both options ?  Thank you.

I want to create a simple figure where images are connected with arrows. Here is what I did:  \begin{tikzpicture} \node[](A) {\includegraphics[width=0.2\textwidth]{a}}; \node[right=1mm of A](B) {\includegraphics[width=0.2\textwidth]{b}}; \draw[->] (A) to (B); \end{tikzpicture}     But I want the arrow to start and end right at the images with no space between. How can I do that?


I have an old netbook and I wanna use it again.  It's a Positivo Mobile, MOBO M900.  Netbook setup:   1.2ghz processor  512 mb ram  4gb hd winXP   Is there any linux distro that I can use?  I have an USB stick with ubuntu 12.04, but since it needs more than 4gb HD, it doesnt even starts the installation.  I booted my netbook from USB and pressed "try before installing" and "install ubuntu"; on both options, the only thing that happened was the netbook showing a black screen for more than 1h.

For a given hardware configuration, how do I find out if Ubuntu will run on it? What considerations should I take into account when choosing an Ubuntu version and  such as:    with a lighter desktop than the usual Gnome and Unity  with the even lighter LXDE desktop   Obviously Ubuntu does not run on some processor architectures. So how do I go about choosing the right version and derivate. How can I find out the minmal system requirements?


$$\frac{(2a+b+c)^2}{2a^2+(b+c)^2}+\frac{(2b+c+a)^2}{2b^2+(c+a)^2}+\frac{(2c+a+b)^2}{2c^2+(a+b)^2}\le8$$ My way was open each parenthesis and try to simplify but that was so long and at the end of that I found that i had mistake could you help me?

Prove that $$\frac{(2a+b+c)^2}{2a^2+(b+c)^2}+\frac{(2b+c+a)^2}{2b^2+(c+a)^2}+\frac{(2c+a+b)}{2c^2+(a+b)^2} \le 8$$.   MY ATTEMPT:I want to make a relation between $a,b,c$. By trial I found that if we put $a=b=c=1$ then the above inequality holds(equality also holds). So by trial I assume that $a+b+c=3$. After that the three functions become of the form of the function below: $f(x)=\frac{(x+3)^2}{2x^2+(3-x)^2}$. I calculate the function and found that : $f(x) \le ⅓(4x+4)$. Am I do right . Anybody has other ideas.


I am traveling to Uji Kyoto Japan and I’m very interested in having a retreat involving Buddhism and teas, especially Matcha Green Tea. I want to get away maybe in a Temple and get the whole Zen experience.

Are there Zen temples in Japan that allow staying there for a few months for meditation for foreigners? How much does that cost? Are there free ones? How about visa?


I have the Kali 4.14.0-kali3-amd64 #1 SMP Debian 4.14.12-2kali1 (2018-01-08) x86_64GNU/linux I followed the instructions  depicted here for my specific card Intel® Dual Band Wireless-AC 3160 I copied the content into home/lib/firmware/but still Linux Kali doesn't detect the wi-fi adaptor. What can I do to remedy it?

I'm trying to enable Wireless on VirtualBox in my Ubuntu 14.04. I use a Kali Linux as the guest OS, but this OS not show the wi-fi when I connect it.    After starting the guest OS, it still does not show the wi-fi     I already tried the suggestions from  and , but my virtualbox does not enable my wireless.


Consider choosing $\theta^*$ that minimizes the expected absolute loss:  \begin{align} \tag{1} \int_{\Theta}|\theta-\theta^*|\pi(\theta|\mathbf{x})d\theta= \int_{-\infty}^{\theta^*}(\theta^*-\theta)\pi( \theta|\mathbf{x})d\theta+\int_{\theta^*}^{\infty}(\theta-\theta^*)\pi(\theta|\mathbf{x})d\theta \end{align}  Differentiating with respect to $\theta^*$ and equating to zero yields: \begin{align} \tag{2} \int_{-\infty}^{\widehat{\theta^*}}\pi(\theta|\mathbf{x})d\theta = \int_{\widehat{\theta^*}}^{\infty}\pi(\theta|\mathbf{x})d\theta \end{align}  EDITED:  I'm confused about the step taken from (1) to (2), which can be found on p. 12 (94) in  (Note: I replaced $\delta(\mathbf{x})$ by $\theta^*$) . A more detailed insight will be highly appreciated. My understanding is that it makes use of Leibniz rule. Here $\widehat{\theta^*}$ is the Bayes estimate (which turns out to be the median of $\pi(\theta|\mathbf{x})$), an argument that minimizes (1).

I'm solving a problem where I've this 'expectation': $$ \int_{0}^y x\cdot f(x) dx $$ where $f(x)$ is a PDF with support on $[0, z]$, with $z>y$. Is there a way to rewrite it without the integral and as a function of the CDF? I've tried integration by parts, but without great success: $$ \int_{0}^y x\cdot f(x) dx = y\cdot F(y) -\int_0^y F(x) dx $$ I have hard time to solve the second part.


My question is simple and possibly stupid, but I wanted to know hypothetically what would happen if two objects start moving away from each other at half the speed of light (0.5c). Is the observed speeds from within the two objects the speed of light.   And if that is the case what happens when two objects move away from each other at the speed of light, is the observed speed from within the two objects 2c? If so doesn't that exceed the perceived speed of light? Does that also imply then that each light particle is possibly moving away from each other at 2c and not just c.  Also, what does a bystander then observe for the 0.5c experiment. Does he observe 0.5c for each object or does he see the two objects depart at the speed of light.   Could all of this imply that the speed of light is simply relative to the point of observation/measurement. Similar to measuring the position of an electron, which in a sense is everywhere and nowhere at the same time and only appears at the time of measurement. Making it less constant and more of a variable.

Let's say we have $2$ particles facing each other and each traveling (almost) at speed of light.    Let's say I'm sitting on #$1$ particle so in my point of view #$2$ particle's speed is (almost) $c+c=2c$, double light speed? Please say why I am incorrect :)    EDIT: About sitting me is just example, so in point of view of #1 particle, the second one moves at (almost) $c+c=2c$ speed?


I'm trying to prove the converse of Lagrange's theorem holds for when $G$ is an abelian group such that $|G|=n$.  What I have is if $k > 1$ and $k|n$, there is a subgroup of prime order $p$ ($p$ is such that $p|k$) of $G$, say $N$, which is normal in $G$.  Consider the canonical epimorphism $\phi: G \to G/N$. Then $G/N$ is abelian group of order $n/p <n$, and I have by induction hypothesis that the converse holds for every abelian group of order less than $n$ so there is a subgroup of order $k/p$ of $G/N$, say $H$. How do I prove that $|\phi^{-1}(H)|=k$?

I'm trying to prove that the converse of Lagrange's theorem is true for finite abelian groups (i.e. "given an abelian group $G$ of order $m$, for all positive divisors $n$ of $m$, $G$ has a subgroup of order $n$"). This is an exercise from a book, and it is in the section on finite abelian groups, so I know I have to use the fundamental theorem of finite abelian groups. I have come up with a proof, but it seems a bit messy, and I'm not entirely sure if it's correct. It is given below.     Let the order of $G$ be $m$ = $p_1^{\alpha_1} \ldots p_k^{\alpha_k}$. It is known that $G$ is a direct product of $p$-groups, say:      $$G = G_1 \times \ldots \times G_k$$      where each $G_i$ is a $p_i$-group. By the fundamental theorem of finite abelian groups, each $G_i$ is isomorphic to a direct product of cyclic groups of the form      $$\mathbb{Z}_{{p_i}^{\beta_1}} \times \ldots \times \mathbb{Z}_{{p_i}^{\beta_l}},$$      where $\beta_1, \ldots, \beta_l$ are positive integers such that $\sum_{j=1}^l \beta_j = \alpha_i$. Now if $n$ divides $m$, then we must have      $$n = p_1^{\gamma_1} \ldots p_k^{\gamma_k}$$      for some $\gamma_1, \ldots, \gamma_k$ with $0 \leq \gamma_i \leq \alpha_i$.      Claim: Each $G_i$ has a subgroup of order $p_i^{\gamma_i}$      Proof: As above, we have that       $$ G_i \cong \mathbb{Z}_{{p_i}^{\beta_1}} \times \ldots \times \mathbb{Z}_{{p_i}^{\beta_l}} $$      where $\beta_1, \ldots, \beta_l$ are positive integers such that $\sum_{j=1}^l \beta_j = \alpha_i$.      Now since $0 \leq \gamma_i \leq \alpha_i$, we can find   $l$ numbers $\delta_1, \ldots , \delta_l$ such that $\gamma_i = \sum_{j=1}^l \delta_j$, and $0 \leq \delta_j \leq \beta_j$. (This choice of numbers is not necessarily unique).      Then $p_i^{\delta_j} | p_i^{\beta_j}$ for each $j = 1, \ldots , l$. Hence, for each factor $\mathbb{Z}_{{p_i}^{\beta_j}}$, there exists a subgroup of order $p_i^{\delta_j}$, namely $\mathbb{Z}_{{p_i}^{\delta_j}}$ (using the fact that the converse of Lagrange's theorem is true for finite cyclic groups). Taking the direct product of each of these subgroups, we get a new subgroup $G_i'$ of $G_i$:      $$G_i' \cong \mathbb{Z}_{{p_i}^{\delta_1}} \times \ldots \times \mathbb{Z}_{{p_i}^{\delta_l}}$$      The order of this subgroup is $p_i^{\delta_1} \times \ldots \times p_i^{\delta_l} = p_i^{\delta_1 + \ldots + \delta_l} = p_i^{\gamma_i} $. So we have found a subgroup of $G_i$ of order $p_i^{\gamma_i}$, as required.      So each factor $G_i$ in the product $G = G_1 \times \ldots \times G_k$ has a subgroup $G_i'$ of order $p_i^{\gamma_i}$.       Therefore, $G$ has a subgroup   $$G_1' \times G_2' \times \ldots \times G_k'$$       of order $p_1^{\gamma_i}...p_k^{\gamma_k} = n$, which completes the proof.   I have two questions about this: firstly, does this proof seem to work? Secondly, is there a way to make the proof more concise (e.g. a way to prove the statement without using all these indices)?


How do I prove that the integral ${\displaystyle\int_0^1}{\dfrac{ln(x)}{1-x^2}dx}$ converges? I tried to find a converging on $[0,1]$ function $g(x)$ such as $g(x) > \dfrac{-ln(x)}{1-x^2}$, but I couldn't succeed in finding it as of yet.

Find whether the integral converges or diverges. $$\int_{0}^{1}\frac{\log(x)}{1-x^2}dx$$  I simplified it to $$\int_{0}^{1}\frac{\log(x)}{(1-x)(1+x)}dx$$  Here I have $2$ "bad" bounds (both $0$ and $1$).  I think, to prove such integral converges, I should find something that is equivalent to or less than $\log(x)$ so I can exchange them, maybe $\sqrt{x}$, so it may cancel out the fraction, and I can compare it to $$\int_{0}^{1}\frac{dx}{x^p}$$  Also I had an idea to substitute $x$ with $u+1$ so I can use $\log(1+u) \sim  u$ when $u \rightarrow 0$. I'm allowed(not familiar with anything else) to use direct comparision test, limit comparision test, Cauchy test and Abel-Dirichlet's test.   Any hints are much appreciated, I just want to get the big picture.   Thank you.


So far I have checked the tolerance value, VIF and condition indexes. But checking the variance of the regression coefficients I have to wonder: how little variance of the regression coefficient should be associated with the smallest eigenvalue and what is too much (indicating multicollinearity)?


I have a home server with Ubuntu and I want to measure download and upload speed in my LAN. Is there any program for Ubuntu that will help me do this?

Instead of going to sites like , I want to check my current Internet speed from the terminal on Ubuntu. How can I do it?


When I try to execute the following function in Java:  public static int myfunc (int x) {     try {         return x;     } finally {         x++;     }        } public static void main (String args[]) {     int y=5,z;     z = myfunc(y);     System.out.println(z); }   The output printed on the console is 5, where as one would expect 6 to be printed. Any idea why?

Considering this code, can I be absolutely sure that the finally block always executes, no matter what something() is?  try {       something();       return success;   }   catch (Exception e) {        return failure;   }   finally {       System.out.println("I don't know if this will get printed out"); }


On questions that get closed by the dupe-hammer, the fold tags badge doesn't show up nicely inside its box on the mobile site.    Also, when a moderator closes, just a little space after the diamond might improve visibility.

When I vote to close as a duplicate on the regular site it shows the gold badge behind my name:    That does work for the web site, but that doesn't show up in the mobile website:    Sample question I closed: .  Can this be fixed please?  (using iPhone 6 on iOS 8.3)    The problem still exists, also with the diamond/dupe-hammer combination:    Also, when a moderator closes, just a little space after the diamond might improve visibility.


It looks like Ubuntu Server 14.04 just released today includes OpenSSL v1.0.1f which is vulnerable to the heartbleed bug.  I've updated my packages (apt-get update) but that's the latest version available.  How to do I upgrade to 1.0.1g so I'm not vulnerable?

As of today, a  has been found affecting versions 1.0.1 through 1.0.1f (inclusive) and 1.0.2-beta.  Since Ubuntu 12.04, we are all vulnerable to this bug. In order to patch this vulnerability, affected users should update to OpenSSL 1.0.1g.  How can every affected user apply this update now?


Let X be a complex Hilbert space with the inner product $\langle⋅,⋅\rangle$ and norm $||⋅||$. Suppose T is a bounded linear operator on $X$ and $T$ is positive definite, means there is a constant $K>0$, such that $K\langle x,x\rangle \leq \langle T(x),x\rangle$, prove $T$ has a bounded inverse $T^{-1}$ and the norm of $T^{-1}$ is less than or equal to $K$.  I simply put $K$ into the inner product, then $K\langle x,x\rangle \leq \langle T(x),x\rangle$, is that means  $Kx \leq T(x)$? hope get prove of this question

Suppose that $H$ is an Hilbert space, and $T: H \to H$ is a self-adjoint strictly positive operator (i.e. $\langle Tx,x\rangle > 0$ for all $x \neq 0$). How do I show that this operator is invertible? For example, I want to show that $\langle Tx , x\rangle$ is bounded below by some positive constant (and then I am happy, I know the rest).  Thank you, Sasha


When trying to say a sentence with the following structure:     You also have [x] possibility to open a savings account   When is it appropriate to use 'a' and when is it appropriate to use 'the'?

I can’t for the life of me figure out where to use a and where to use the — and where there is no article at all. Is there a simple rule of thumb to memorize?   The standard rule you always hear:     “If a person knows which item you are talking about then use "the"   . . . doesn’t clear things up for me, as I have no idea whether or not they know.


I am working on a web project that has nearly 100 thousand instant users and there is a webpage that we are using for test cases. There are no links pointing to it from other pages. It shouldn't be indexed by Google or any other search engines.  "" can be used in this situation, I know but I wonder if Google (or any others) indexes this page, if I don't do anything to prevent it.

I am building a new site, but creating the content using a subdirectory on an existing site. I have never posted a link to this subdirectory anywhere, yet searching Google reveals that Google has found these pages on my site and indexed them.  Further, I updated the site with a robots.txt file that WMT reports as being read, and testing the blocked pages using the WMT test tool indicates that the pages will not be indexed. Apparently this does not remove the pages from existing results, though I submitted a request to do so.  How did Google find these pages to begin with? Is it because I used a common subdirectory name and Google guesses at common subdirectories?


Both my children used to play in each other worlds on two separate iPads, since upgrading the minecraft every time they try to play together it keeps just saying invalid name.

I am having trouble getting onto a server in Minecraft PE on iOS. When I tap on the person's server it just says invalid name:    I have tried turning off and restarting the iPad, going to home screen and logging back into the server but I have had no luck and no change. Is there a reason why this is so?


I have AMD A10 6800K, which is APU(is a CPU with GPU included) and I wonder what are the safe temps for the WHOLE package, I don't if I'm mistaking or not.   I know the ideal temperature for AMD A10-6800K is 74Cº. Is 74Cº for the CPU or the whole APU?  My normal temperatures for(the max shows when I'm playing):   CPU:  Max- 70Cº  Min- 44Cº(when idle)  GPU: Max- 40Cº Min- 8Cº(when idle)  whole APU: Max- 113Cº Min- 62Cº    I'm using the heatsink and cooler that came with the APU and another cooler from the case Cooler Master K350.

I have an A10-6800K CPU and Piriform Speccy says that my CPU temp is 66 celcius in idle, the same goes for HWMonitor.  Is this normal/ideal? I have a  with a .


I have variables which I put inside an array. When I loop through the array I assign values to the variables. When I console.log(variable) it returns undefined.  Example:  var test1, test2; var tests[test1, test2]; function change(){ for(var i=0;i<tests.lenght;i++){    tests[i] = i; }} change(); console.log(test1); //returns undefined   Shouldn't the output be 0? What am I missing?  Edit  I think I understand now, but how to apply to specif problem:  var table1 = {}; var table2 = {}; var tables = [table1, table2];  function initiDataTables(urlsToInit){         for(var i = 0; i<tables.length; i++){             var tempUrl = urlsToInit[i];             var name = '#example'+i.toString();             var name2 = name + ' tbody';             console.log(name);             tables[i].val = $(name).DataTable({                 'autoWidth'   : false,                 'ajax': {                     'url' : tempUrl,                     'dataSrc' : '',                 },                 'columns': [                     {'data':'ID'},                     {'data':'Naziv'},                     {'data':'File'},                     {'defaultContent':"<button id='btnView1' class='btn btnview btn-primary'>Prikaži</button>"},                     {'defaultContent':"<button id='btnDelete1' class='btn btndel btn-danger'>Obriši</button>"},                 ],                 'columnDefs' : [                     { 'visible': false, 'targets': [2] }                 ]             });              console.log('Check' + table1);               $(name2).on( 'click', '.btnview', function () {                 var data = tables[i].val.row( $(this).parents('tr') ).data();//here it gives me undefined                 window.open('Images/'+data.File, 'window name', 'window settings');             } );              $('.dataTableServer').on( 'click', '.btndel', function () {                 var data = tables[i].row( $(this).parents('tr') ).data();                 //deleteData('news', data.ID);             } );         }        }   I am trying to initialize multiple datatables.

The primitive types (number, string, etc.) are passed by value, but objects are unknown, because they can be both passed-by-value (in case we consider that a variable holding an object is in fact a reference to the object) and passed-by-reference (when we consider that the variable to the object holds the object itself).  Although it doesn't really matter at the end, I want to know what is the correct way to present the arguments passing conventions. Is there an excerpt from JavaScript specification, which defines what should be the semantics regarding this?


I am currently facing an issue I do not know how to track.  I put the start-in option of a prompt command to :  C:\Users\XXX\Downloads   Then apply and finally when I open the prompt command, it starts in:  C:\Users\XXX\Documents>   I remember one year ago I modify the registry to start in documents folder, and this is certainly the reason why it overloads the prompt command value I set up. But I am clearly not able anymore to know which key it is ... does someone have an idea?

My new Windows XP work computer's command prompt automatically brings up "H:\>" when I open it.  Is there a way for me to change that safely?  Specifically, to "C:\foo\bar\Something Else"?  I found the method of changing the Autorun value through Google, but it came with a warning that it "might affect the functionality of batch scripts."  Bonus note: I was originally getting at this issue in , but I didn't ask very directly.  The answer I ended up accepting was really good, so I wanted to leave it there.


The FreeBSD  has instructions on building a jail distribution tree:   D=/here/is/the/jail  cd /usr/src  mkdir -p $D  make world DESTDIR=$D  make distribution DESTDIR=$D   Is it possible to do this with a non-root account? Right now, with a regular user account, I get:  $ make world DESTDIR=/jails/base/ [Creating objdir /usr/obj/usr/src/amd64.amd64...] mkdir: /usr/obj/usr: Permission denied make: "/usr/src/share/mk/auto.obj.mk" line 69: could not use /usr/obj/usr/src/amd64.amd64: .OBJDIR=/usr/src   If I'm building into a jails directory, I don't see why root privilege is necessary. Is it possible?

I am trying to build a custom FreeBSD disk image from source which I could then load with bhyve.  Here's the script I use:  export MAKEOBJDIRPREFIX="$HOME/obj" export CHROOTDIR="$HOME/var" ncpu="$(sysctl -n hw.ncpu)"  set -e     cd  mkdir -p obj mkdir -p var  svn co http://svn.freebsd.org/base/head ./src cd src make -j$ncpu -DNO_CLEAN buildworld buildkernel  cd release make release -DNODOC -DNOSRC -DNOPORTS make install DESTDIR=../../var   My problem is that make release fails.   What is wrong?    Here are some parts of the make release error message:     ...  .:      user (0, 1001, not modified: Operation not permitted) bin:    user (0, 1001, not modified: Operation not permitted) boot:   user (0, 1001, not modified: Operation not permitted) boot/defaults:         user (0, 1001, not modified: Operation not permitted) boot/dtb:         user (0, 1001, not modified: Operation not permitted) boot/firmware:         user (0, 1001, not modified: Operation not permitted) boot/kernel:         user (0, 1001, not modified: Operation not permitted) boot/modules:         user (0, 1001, not modified: Operation not permitted) boot/zfs:         user (0, 1001, not modified: Operation not permitted) dev:    user (0, 1001, not modified: Operation not permitted) etc:    user (0, 1001, not modified: Operation not permitted)       ...  -------------------------------------------------------------- >>> Distributing everything -------------------------------------------------------------- cd /usr/home/m/src; make -f Makefile.inc1 distribute ===> lib (distribute) ===> lib/csu (distribute) ===> lib/csu/amd64 (distribute) cd /usr/home/m/src/lib/csu/amd64;  make install installconfig -DNO_SUBDIR DESTDIR=/usr/home/m/obj/usr/home/m/src/release/dist/base SHARED=copies install  -o root -g wheel  -m 444 crt1.o crti.o crtn.o Scrt1.o gcrt1.o /usr/home/m/obj/usr/home/m/src/release/dist/base/usr/lib/ install: /usr/home/m/obj/usr/home/m/src/release/dist/base/usr/lib/crt1.o: chown/chgrp: Operation not permitted *** Error code 71       ...


I started reading the Inheritance cycle by Christopher Paolini before I started reading J.R.R Tolkien's Lord of the Rings, and I have to say, they seem pretty similar in the books. Of how Eragon uses the Ancient language for magic, and in LOTR someone tells of mysterious people outside of the Spire, using the language of beasts and land, which describes the Ancient language. I don't know, please help.

Many elements in the Inheritance Cycle, by Christopher Paolini, seem to recall elements of other fantasy works. For example, the four major humanoid species (Urgals, humans, elves, and dwarves) are very Tolkienesque. Galbatorix is something of an Emperor Palpatine. Angela the Herbalist may owe something to Doctor Who. And so forth.  What inspiration has Christopher Paolini admitted to drawing from other fantasy or sci-fi works, whether for specific characters or general concepts?


How do we decide whether the formula in predicate logic is a tautology? Is there some universal way to decide and prove it?  Let's have an example:  $$ \forall x \forall z \exists y\,(P(x,y) \lor P(y,z)) \leftrightarrow \forall x \exists y \forall z\,(P(x,y) \lor P(y,z)) $$  I was adviced to choose some Universum and it's realisation but I don't know how to do that.   Could you help me to solve it?

How do we decide whether the formula in predicate logic is a tautology? Is there some universal way to decide?  Let's have an example:  Vx(P(x)&Q(x))<->VxP(x)&VxQ(x)   My solution (not correct and not complete)  So the first thing I do is to rename some variables on the right side.   Vx(P(x)&Q(x))<->VxP(x)&VyQ(y)   No, I can do this:  Vx(P(x)&Q(x))<->Vx(P(x)&VyQ(y))   And this:  Vx(P(x)&Q(x))<->VyVx(P(x)&Q(y))   So my question is:   How can I decide and proove, whether it is a tautology?


This is basically all Revenge of the Sith spoilers, so read on at your own peril.  The second to last scene of Revenge of the Sith features Darth Vader and the Emperor overseeing the construction of the first Death Star. Several things imply this takes place some time after the film's main narrative.   The Star Destroyers have been remodeled.       The Republic Navy has transitioned into the Imperial Navy and the officers have received new uniforms.       Vader has gotten used to his armor and the Imperial officers have gotten used to Vader.     How much time has passed?  Edit: Some people are claiming my question is a duplicate of this . However, all the linked question's answers state is that the Death Star was in construction during the Clone Wars. They do not mention any of the clues that this scene takes place at a later date, nor do they state when the scene actually takes place.

I ask this because at the end of the movie, you see Luke on Tatooine, Leia with Bail Organa, and then a decent portion of the Death Star already done as Palpatine & Vader look on. So it seems the station was already under construction during the Republic. Or was there just some random time gap between these scenes?  Here is the scene in question:


Im trying to make a seating chart and the way im going about it doesn't seem to be working and i really need some help with assigning a value (each value will be a seat number on a little chart i made) to a variable (a students name). The problem i keep having is im trying to use a list to store what seats (numbers) i already have assigned to one student. Then if the seat value is already in the list, it should go back to get a new value and the repeat the checking process to see if the new value is taken and so on. in python it would just be something as simple as   def main():     x = Random.randint(1,20)     main()     <----this go back to type function is what i need to know in c#   below is my code in c#  public void Button_Click(object sender, EventArgs e)     {               int a = getValue();         int b = getValue();         int c = getValue();         int d = getValue();         int ee = getValue();         int f = getValue();         int g = getValue();         int h = getValue();         int i = getValue();         int ff = getValue();         int gg = getValue();         int hh = getValue();         int ii = getValue();         int j = getValue();         int k = getValue();         int l = getValue();         int m = getValue();         int n = getValue();         int o = getValue();         int p = getValue();         int q = getValue();         int r = getValue();         int s = getValue();         int t = getValue();         int u = getValue();         int v = getValue();         int w = getValue();         int x = getValue();         int y = getValue();         int z = getValue();         int AA = getValue();         int BB = getValue();           Dictionary<string, int> studentNames = new Dictionary<string, int>();         studentNames.Add("a", a);//1         studentNames.Add("b", b);         studentNames.Add("c", c);         studentNames.Add("d", d);         studentNames.Add("e", ee);         studentNames.Add("f", ff);         studentNames.Add("g", gg);         studentNames.Add("h", hh);         studentNames.Add("i", ii);//9         studentNames.Add("j", j);         studentNames.Add("k", k);         studentNames.Add("l", l);         studentNames.Add("m", m);         studentNames.Add("n", n);         studentNames.Add("o", o);         studentNames.Add("p", p);         studentNames.Add("q", q);         studentNames.Add("r", r);         studentNames.Add("s", s);         studentNames.Add("t", t);//20         studentNames.Add("u", u);         studentNames.Add("v", v);         studentNames.Add("w", w);         studentNames.Add("x", x);         studentNames.Add("y", y);         studentNames.Add("z", z);         studentNames.Add("AA", AA);         studentNames.Add("BB", BB);//28     }      public int getValue()     {         List<int> usedNumbers = new List<int>();         Random rnd = new Random();         int tempValue = rnd.Next(0, 27);          if (usedNumbers.Contains(tempValue))         {  // Go back to getValue() to have the tempValue get a new value         }         else         {              usedNumbers.Add(tempValue);              return tempValue;         }     } }

What is the best way to randomize the order of a generic list in C#? I've got a finite set of 75 numbers in a list I would like to assign a random order to, in order to draw them for a lottery type application.


As above, how would you go about proving this inequality?

Prove that $$\forall x,y \in \mathbb{R}:\vert\cos x- \cos y\vert\leq\vert x-y\vert.$$  My try : $ f(x) =\cos x$ and use the mean value theorem.


Consider the following code:  public class Office {     int room;     Office(int room) {         this.room = room;     } }  class Test {   public static void F2(Office o1, Office o2) {       o2 = o1;       o2.room = 63;   }   public static void main(String[] args) {       Office labOffice = new Office(130);       Office commonOffice = new Office(275);       F2(labOffice, commonOffice);       System.out.println(labOffice.room + ", " + commonOffice.room);   } }   Inside method F2, after setting o2.room to 63, shouldn't both o1.room and o2.room become 63? Why does printing still give me 275 for commonOffice?

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'm using Bada OS Version 1.2 on my Samsung Wave 2 S8530.  My phone's hardware is: ⠀• 1GHz processor ⠀• 512MB RAM ⠀• 2GB Internal memory ⠀• Hummingbird chipset ⠀• 73MB GPU memory    I have a 32GB UHS 1 Class 10 microSD card. Please tell me can I install Ubuntu on my phone?

With the announcement of the Ubuntu Phone OS I'd like to know what phone (and tablet) models are supported at this time.  Note from foss & Oli: We are making this the master question for all future "Will this work on <insert random tablet/phone/device here>?!" questions


The above question has been open for well over a week now, it's got no comments, no answers and only 23 views or so (judging by Jeff's answer  that shouldn't be the factor anyway!)  It does have one close vote though, that's the only thing I can think of?  All the other questions about this seem to have been resolved when the user already had the tumbleweed badge - I however don't!  Any ideas?

Formerly List of all badges with full descriptions.  What are badge name's requirements? Why didn't I get badge name ? Which badges can I earn multiple times?    Jump to:                    Note: Some badges are awarded based on score. The term score means the total number of upvotes minus the total number of downvotes.  Any badge with a *** next to it is one of 20 badges that count towards the  displayed on a moderator candidate in an election. The candidate score is a total of 40 points: the first 20 are awarded based on the user's rep divided by 1000 and rounded down; the second 20 represents the total number of unique badges earned of the 20 that count. Note that if the same badge is earned multiple times, it will only count once towards the candidate score.  Any badge with a "(retired)" next to it is no longer awarded, but is retained by users who previously earned them. See  for more info on what it means for a badge to be retired.       Visit the  of the  on any site to see a complete list of badges that you can filter by earned, unearned, or type.


Saw this question in a test, but got stuck, here is my attempt: \begin{align} \frac{2}{\pi} \int_{0}^{2\pi} f(e^{i\theta})\cos^2\bigg(\frac{\theta}{2}\bigg)\,d\theta &= \frac{2}{\pi} \int_{0}^{2\pi} f(e^{i\theta})\frac{1+\cos(\theta)}{2}\,d\theta \\ &= \frac{1}{\pi} \int_{0}^{2\pi} f(e^{i\theta}) +  \frac{1}{\pi} \int_{0}^{2\pi} f(e^{i\theta})\cos(\theta)\,d\theta \\ &= 2f(0) + \frac{1}{\pi} \int_{0}^{2\pi} f(e^{i\theta})\cos(\theta)\,d\theta . \end{align} Now it only remains to show $$ \frac{1}{\pi} \int_{0}^{2\pi} f(e^{i\theta})\cos(\theta)\,d\theta = f'(0), $$ but this where I am stuck.  From Cauchy's formula: \begin{align} f'(0) &= \frac{1}{2\pi i} \int_{0}^{2\pi} \frac{f(e^{i\theta})}{e^{2i\theta}}ie^{i\theta}\,d\theta \\ &= \frac{1}{2\pi} \int_{0}^{2\pi} \frac{f(e^{i\theta})}{e^{i\theta}}\,d\theta \\ &= \frac{1}{2\pi} \int_{0}^{2\pi} f(e^{i\theta})e^{-i\theta}\,d\theta \\ &=\frac{1}{2\pi} \int_{0}^{2\pi} f(e^{i\theta})\cos(\theta)\,d\theta - \frac{i}{2\pi} \int_{0}^{2\pi} f(e^{i\theta})\sin(\theta)\,d\theta, \end{align} Which is clearly not $$ \frac{1}{\pi} \int_{0}^{2\pi} f(e^{i\theta})\cos(\theta)\,d\theta$ unless $\int_{0}^{2\pi} f(e^{i\theta})\sin(\theta)\,d\theta = 0. $$ I haven't a clue as $$ \int_{0}^{2\pi} f(e^{i\theta})\sin(\theta)\,d\theta = 0 $$ or whether this actually makes sense. Any help would be appreciated.

I am trying to establish that  $$\frac2{\pi}\int_0^{2\pi} f(e^{i\theta})\cos^2\left(\frac{\theta}{2}\right)\;\mathrm d\theta=2f(0)+f^\prime(0)$$  for $f$ analytic on $|z| < R,\; R > 1$  I think I am making a mistake somewhere, please point it out to me.Here's what I've done unsing the mean value property and Cauchy's integral formula:  $$2f(0)+f'(0)=2(\frac1{2\pi}\int_0^{2\pi} f(e^{i\theta})d\theta + \frac1{2\pi i}\int_0^{2\pi}\frac{f(e^{i\theta})ie^{i\theta}}{e^{i2\theta}}=\frac{1}{\pi}\int_0^{2\pi} f(e^{i\theta})d\theta\frac1{2\pi}\int_0^{2\pi}\frac{f(e^{i\theta})}{e^{i\theta}}\quad\text{(1)}$$  But when I develop the expression $\frac2{\pi}\int_0^{2\pi} f(e^{i\theta})\cos^2(\frac{\theta}{2}) d\theta$ I get:  $$\frac1{\pi}\int_0^{2\pi} f(e^{i\theta})d\theta+\frac1{2\pi}\int_0^{2\pi}f(e^{i\theta})[{e^{i\theta}}+e^{i-\theta}]d\theta \quad\text{(2)}$$  The second integral in (1) differs from the second integral in (2). Thanks.


I have used a table to insert images using the . The problem is that I have several images to be placed and hence the images start getting hide behind the bottom of the page as shown  (one of my previous question).   PROBLEM: Though I can use \ContinuedFloat as suggested in the comments of that question but then the next part of the image comes in the middle of the next page (if there is only 1-2 rows in the continued part of the table) which looks weird. So, how can I bring the continued part of the table to the top of the next page so that they really look in continuation.      \documentclass{article}     \usepackage[caption=false]{subfig}     \usepackage{graphicx}     \usepackage{tabularx}      \newcolumntype{Y}{>{\centering\arraybackslash}X}      \begin{document}      \begin{figure}     \subfloat[First layer]{%     \begin{minipage}{\linewidth}       \centering       \begin{tabularx}{\linewidth}{YYY}       \includegraphics[width=\linewidth,height=1cm]{example-image-a}         & \includegraphics[width=\linewidth,height=1cm]{example-image-b}         & \includegraphics[width=\linewidth,height=1cm]{example-image-c} \\       First image & Second image & Third image \\         \includegraphics[width=\linewidth,height=1cm]{example-image-a}         & \includegraphics[width=\linewidth,height=1cm]{example-image-b} \\       Fourth image & Fifth image &       \end{tabularx}       \end{minipage}}\par\medskip      \subfloat[Second layer]{%     \begin{minipage}{\linewidth}       \centering       \begin{tabularx}{\linewidth}{YYY}       \includegraphics[width=\linewidth,height=1cm]{example-image-a}         & \includegraphics[width=\linewidth,height=1cm]{example-image-b}         & \includegraphics[width=\linewidth,height=1cm]{example-image-c} \\       First image & Second image & Third image \\         \includegraphics[width=\linewidth,height=1cm]{example-image-a}         & \includegraphics[width=\linewidth,height=1cm]{example-image-b} \\       Fourth image & Fifth image &       \end{tabularx}       \end{minipage}}\par\medskip          \subfloat[Third layer]{%     \begin{minipage}{\linewidth}       \centering       \begin{tabularx}{\linewidth}{YYY}       \includegraphics[width=\linewidth,height=1cm]{example-image-a}         & \includegraphics[width=\linewidth,height=1cm]{example-image-b}         & \includegraphics[width=\linewidth,height=1cm]{example-image-c} \\       First image & Second image & Third image \\         \includegraphics[width=\linewidth,height=1cm]{example-image-a}         & \includegraphics[width=\linewidth,height=1cm]{example-image-b} \\       Fourth image & Fifth image &       \end{tabularx}       \end{minipage}}\par\medskip       \subfloat[Forth layer]{%       \begin{minipage}{\linewidth}       \centering       \begin{tabularx}{\linewidth}{YYY}       \includegraphics[width=\linewidth,height=1cm]{example-image-a}         & \includegraphics[width=\linewidth,height=1cm]{example-image-b}         & \includegraphics[width=\linewidth,height=1cm]{example-image-c} \\       First image & Second image & Third image \\         \end{tabularx}       \end{minipage}}     \caption{a figure with some layers of subfigures each with its own name and each layer with a subcaption}     \end{figure}      \end{document}

I just got a short algorithm on my page, and it keeps getting aligned at the center of the page. But I want to have it aligned at the top, what do I have to do?


I'm creating a bluetooth application and I'm trying to send a data to a private method from a public method but i got this error     java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.Resources android.content.Context.getResources()' on a null object reference   the public method:  public void showTimeSet(long interval, Context context){     if(interval !=0){         Toast.makeText(context,"Countdown second is "+interval,Toast.LENGTH_LONG).show();         String msg= String.valueOf(interval);         try {             sendMessage(msg);         }catch (Exception e){             Log.e(TAG, "showTimeSet Error sending message: "+e);         }     } }   and the sendMessage method:  private void sendMessage(String message) {     // Check that we're actually connected before trying anything     if (mChatService.getState() != BluetoothService.STATE_CONNECTED) {         Toast.makeText(getActivity(), R.string.not_connected, Toast.LENGTH_SHORT).show();         return;     }      // Check that there's actually something to send     if (message.length() > 0) {         // Get the message bytes and tell the BluetoothService to write         byte[] send = message.getBytes();         mChatService.write(send);          // Reset out string buffer to zero and clear the edit text field         mOutStringBuffer.setLength(0);         mOutEditText.setText(mOutStringBuffer);     } }

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 have lot of confusion. I am traveling from Bangalore (India) to Dublin (Ireland) and I have a stopover of 4h15m in London Heathrow; I have to change terminals from 2 to 5.   I have valid Irish Join Family Visa and will have a Resident Permit. Do I still need a transit visa for the UK?  And one more thing: my first airline, Air India, will not transfer my luggage to the connecting flight on British Airways.  If a visa is required, can I get the transit visa on arrival?

Is there a website or some other way to find out if I need a transit visa for a short stop in the UK on my way somewhere else? Ideally this should give me the answer for all nationalities, and take into account any other visas I may have.


I'm installing linux distributions on computers I find in the neighborhood's garbage area.  these computers are, hardware speaking, still working... nothing broken.., problem is: most of these computers are 8-15 years old.  some are netbooks, but most are laptops. a few towers as well.  the target functionality/usage of these computers differs, I give them as charity to people who can't afford a computer but still need access to internet and can't afford smartphone as well. (these people live in a third world country I visit every now and then... don't ask..)  sometimes they just function as live streaming TV for those who don't have TVs or that the only thing in TV is government's brainwash material.  these computers are too low on resources for ubuntu 16.04 (video lagging/delay in visual video compared to sound/video freezes, GUI get's slow and stuck etc.)  my question is: which linux distribution is the most lightweight and will be most potent to work with these kind of computers? doesn't it change by the target use of each computer (as I specified above)? Lubuntu? Xubuntu? Linux Lite?

I'm thinking about installing Ubuntu Desktop, but I don't know what flavor is the best for my system. What are the minimum and recommended hardware requirements? What kind of CPU? How much memory? Should I have Hardware Acceleration? What flavor should I use?  This is an attempt of a canonical answer. My answers have the "official  requirements", the recommended are a mix of official sources and opinion based (along with the answer it's told the source). You can comment or edit if you feel that the information is obsolete or incomplete. It is a good rule of thumb that any system capable of running Windows Vista, 7, 8, x86 (Intel) OS X will almost always be a lot faster with any Ubuntu flavor even if they are lower-spec than described below.


Here is my approach:  Suppose the parallelogram is in the first quadrant.  Then, we can say that $z_1=x_1+iy_1$, $z_2=x_2+iy_2$, and $z_3=x_3+iy_3$.  Let $z_1$ be in bottom left, $z_2$ be in top left, $z_3$ be in top right.  We know that opposite sides of a parallelogram are parallel and congruent.  Then, $z_4=[x_1+|x_3-x_2|]+iy_1$. Now, to continue, I would consider a parallelogram that is totally contained in each quadrant, then start looking at the cases where the parallelogram is partly contained in quadrant..... this seems like a lot of cases.  I was wondering if there would be an elementary way that I could generalize this problem down to a few cases, or even just a single case.  Thank you.

Question :  Let $z_1,z_2,z_3,z_4$ be the position vectors of the vertices for quadrilateral $ABCD$. Prove that $ABCD$ is a parallelogram if only if $z_1-z_2-z_3+z_4=0$  What i've done so far :  Proof of $p\Rightarrow q$  Let $z_1=x_1+iy_1,\quad z_2=x_2+iy_2, \quad z_3=x_3+iy_3, \quad z_4=x_4+iy_4$  $ABCD$ is a parallelogram $\Leftrightarrow\,\overrightarrow{AB}=\overrightarrow{CD}\, \land\, \overrightarrow{AD}=\overrightarrow{BC} $   $\begin{aligned} \overrightarrow{AB}=\overrightarrow{CD} &\Rightarrow |z_1-z_2|=|z_3-z_4|\\ &\Leftrightarrow x_1^2-2x_1x_2+x_2^2+y_1^2-2y_1y_2+y_2^2=x_3^2-2x_3x_4+x_4^2+y_3^2-2y_3y_4+y_4^2\\ \overrightarrow{AD}=\overrightarrow{BC} &\Rightarrow |z_1-z_4|=|z_2-z_3|\\ &\Leftrightarrow x_1^2-2x_1x_4+x_4^2+y_1^2-2y_1y_4+y_4^2=x_2^2-2x_2x_3+x_3^2+y_2^2-2y_2y_3+y_3^2 \end{aligned}$  I'm stuck and see no conclusion here.  Proof $p\Leftarrow q$  I don't have an idea for this.  Please help me, thanks.


Currently running Version 2.14.13  I'm having trouble getting base maps to appear when I go to print a map in QGIS Cloud. I've been using Google Hybrid from the OpenLayers plugin, and while it appears when I pull up my web map, it disappears when I attempt to use the print feature. I realized OpenLayers is outdated so I tried to use the QuickMapServices plugin instead.  I've tried using OSM Standard from the QuickMapServices plugin. However, when I go to publish my map in QGIS, I get an error message stating "Unsupported Layers Found" in reference to the OSM Standard layer. I know there is a way to add a service within the QuickMap setting, but this is a process that I'm not familiar with, nor do I know if this is something that will even make a difference here. I realize I could just upload some aerial photos, but the size of those files doesn't really make it feasible with the amount of DB storage I have left. Any ideas of a solution?

Whenever I try to export a map with the Google Maps plugin in the background, it exports but just exports to a blank document. When I turn the Plugin off so it is not in the background, it prints fine. Why is this?


I would like to change the color of my headings and bullet points from the default blue to my own blue. I have put in the correct rgb (it works with documents like PowerPoint), but somehow my beamer presentation has a different shade of blue than the blue I get in PowerPoint with the same rgb. How can that be? What can I change in my code?  \documentclass{beamer} \usetheme{default} \usecolortheme{default} \definecolor{mine}{rgb}{0,138,171} \setbeamercolor*{palette primary}{bg=mine,fg=white}     \setbeamercolor*{palette secondary}{bg=mine,fg=white}     \setbeamercolor*{palette tertiary}{bg=mine,fg=white}     \setbeamercolor*{palette quaternary}{bg=mine,fg=white}     \setbeamercolor*{structure}{fg=mine} \setbeamercolor*{section in toc}{fg=mine}  \begin{document} \title{My title}   \author{My name} \date{\today}  \begin{frame} \titlepage \end{frame} \end{document}

I have decided to switch from Powerpoint to Beamer, and for my first presentation I'd like to use the , and the same colors as in this goggle slide template:  .  I tried to do some research about it, the closest answers I found are the question  and the . I tried this code:  \documentclass{beamer} \usepackage[frenchb]{babel} \usepackage[T1]{fontenc} \usepackage[utf8]{inputenc}  \usetheme{metropolis}  \definecolor{bluegreen}{rgb}{3, 166, 155} \definecolor{pitchblack}{rgb}{0, 0, 0} \definecolor{lightbeige}{rgb}{255, 251, 241} \definecolor{mediumgray}{rgb}{183, 183, 183}  \setbeamercolor{background canvas}{bg=pitchblack} \setbeamercolor{normal text}{fg=lightbeige} \setbeamercolor{headline}{bg=bluegreen, fg=mediumgray}  \begin{document} \begin{frame}     \frametitle{The title}     Lorem ipsum... \end{frame} \end{document}   I does everything I want, except that the title bar's background color is lightbeige:    What did I do wrong? Or what argument should I pass to \setbeamercolor to get it right? Thanks in advance :-).


I'm checking a variable, say foo, for equality to a number of values. For example,  if( foo == 1 || foo == 3 || foo == 12 ) {     // ... }   The point is that it is rather much code for such a trivial task. I came up with the following:  if( foo in {1: 1, 3: 1, 12: 1} ) {     // ... }   but also this does not completely appeal to me, because I have to give redundant values to the items in the object.  Does anyone know a decent way of doing an equality check against multiple values?

What is the most concise and efficient way to find out if a JavaScript array contains a value? This is the only way I know to do it: function contains(a, obj) {     for (var i = 0; i < a.length; i++) {         if (a[i] === obj) {             return true;         }     }     return false; }  Is there a better and more concise way to accomplish this?


Here's my script  #! /bin/sh  source=/Source/$1 destination=/Destination folderParam=$(basename $source) if /usr/bin/rsync -avh -r $source $destination; then    cp /FolderCopyStatus/Success   /Status/Success_$folderParam;    mysql -h ip -uroot -ppassword  << EOF    use oct_test;    insert into Test(Name,Value,Status) values('rsync',$folderParam,'Ok');    EOF else    cp /FolderCopyStatus/Failure   /Status/Failure_$folderParam;    mysql -h ip  -uroot -ppassword  << EOF    use oct_test;    insert into Test(Name,Value,Status) values('rsync',$folderParam,'Fail');    EOF fi   Error and Warning     /FinalSync.sh: line 18: warning: here-document at line 8 delimited by   end-of-file (wanted `EOF') /FinalSync.sh: line 19: syntax error:   unexpected end of file   I know there is a simple thing that I am missing.Newbie to shell scripting.

I have this if in a bash script:  if [ $ACTION = deploy ]; then     ${JAVA_HOME}/bin/java ${JVM_ARGS} weblogic.WLST << EOJ     connect('XXX','XXX','t3://XXX:8001')     jndi();     ls();     disconnect();     exit ();     EOJ else     echo "XXX" fi   I think the error is in the EOJ.


I would like to know if it is possible to render a transparent animation in Blender to use it as a filter to record video as snapchat does it but with static png filters?

Does anyone know if there are any video formats (besides the HUGE uncompressed avis) that you can render in that maintain the alpha channel? (i.e. for after FX etc.)   I used to use quicktime, but that's no longer an option.  I know you can render in png. or other image formats, but video is significantly smaller, and I often work on machines with less space & resources.


I have started to learn blender. I have a problem with re-changing segments. When I create an object, object panel gives options at left bar but if I close that panel; I couldn't reach it again. I have already searched and found "no, you cannot" answer. But Is there any additional solution? I have used F6 button, it just gives transform panel only.

When you first add a cylinder, you have the option to change the number of vertices, etc, but once you do anything else in blender, it seems you no longer can edit those parameters.   Is there a setting anywhere or an add-on that allows these parameters to be edited later on? If not, how easy would such an addon/feature be to create for anyone reading this?


In linear algebra(I'm the beginner so far), I feel the concepts and ideas are based on on another, like layer by layer, and there are many relations among the properties.  For example, Matrix Multiplication, AB is essentially the composition of Linear Transformation（$A(Bx)=(AB)x$ to manually define AB) , and Linear Transformation is also from Matrix Equation($Ax=b, T(x)=b=Ax$)，and Matrix Equation is also from Vector Equation($x_1a_1+...+x_na_n=b$ equivalent to $Ax=b$)，and finally Vector Equation is the basic System of Linear Equations.  so Vector Equation could be intuitively understood as Linear System，Matrix Equation is just another formation。 Linear Transformation is fine too，but when it comes to Matrix Algebra， like Inverse Matrix and its properties, it seems very hard to be intuitively understood through the basic System of Linear Equations. It'll be only fine when I admit the manually definition the matrix multiplication from composition of linear transformation. Because as the process moves on, it's more and more like everything is constructed layer by layer, and more and more complicated as it's very hard to try to understand it from the very basic layer (e.g. linear system) intuitively.  I'm not sure whether it's the normal situation, because there are also intersected properties among many 'layers'. Therefore the whole 'knowledge structure' is not very clear in my brain.  And, when I think of the the basic Quadratic Formula in elementary algebra, ， its meaning is just to solve the quadratic equation with one variable, and then it is proved from completing square of $ax^2+bx+c=0$ to find general formation of $x$. But it is still impossible to 'understand thoroughly' from the original equation like how the relation among each variable and coefficient. So when I need to use it, I just refer to the book or prove it myself (assume if I forget)   So will it the same thing as learning the Linear Algebra, like the determinant of matrix,  $\det A = \sum_{j=1}^{n}(-1)^{1+j}a_{1j}\det A_{1j}$. Is it okay that what I need to do is only to know two things,    What it really is.  How to prove it.   (When I use it, just refer to book or prove it, however, prove the determinant takes a little long time). Because this formula ($\det A$) is already impossible to be thoroughly understood from the very basic 'layer' like system of linear equations or even vector equation. I only know, Firstly its meaning is to determine whether a matrix is invertible (because invertible matrix must has $n\times n$ size and has pivot position in each row and no zeros in diagonal entries.), Secondly it's proved from $n\times n$ matrix row reduced to echelon form, then the right-bottom corner must be nonzero, the above formula is just the brief formation of the item in right-bottom corner.  I know this two things,could I say I'm already understand it ?  Because even though I know 1.what is really is and 2.how to prove it, but I'm still not able to remember it when use it.

In my linear algebra class, we just talked about determinants. So far I’ve been understanding the material okay, but now I’m very confused. I get that when the determinant is zero, the matrix doesn’t have an inverse. I can find the determinant of a $2\times 2$ matrix by the formula. Our teacher showed us how to compute the determinant of an $n \times n$ matrix by breaking it up into the determinants of smaller matrices. Apparently there is a way by summing over a bunch of permutations. But the notation is really hard for me and I don’t really know what’s going on with them anymore. Can someone help me figure out what a determinant is, intuitively, and how all those definitions of it are related?


I'm seeing the red alert on sites where there's nothing to review:    That's from Community Building, where I'm pretty sure the queues are empty.  I also just saw it on Worldbuilding meta, where I'm a moderator and also see nothing special (like pending VLQ/NAA flags).  And it's sticking around after I close the dialogue.  Visiting one of the review queues from the drop-down didn't dismiss it either.

On all Stack Exchange sites where I have review privileges, the review queue menu icon has a red dot. No matter what I try, it doesn't go away.     on Meta Stack Overflow might or might not be related.


I do understand the proofs, I've read, for the countability of $\mathbb{Q}$ and the uncountability of $\mathbb{R}$, but I don't intuitively understand how the set of irrational numbers can be uncountable, and is therefore, intuitively speaking, a lot larger than the set of all rational numbers, yet at the same time for all real numbers there exists a rational number such that the rational number can be put between any two real numbers. If this could be done for all real numbers, how can there be way more irrational numbers than rational numbers?

I've been told that the rational numbers from zero to one form a countable infinity, while the irrational ones form an uncountable infinity, which is in some sense "larger". But how could that be? There is always a rational between two irrationals, and always an irrational between two rationals, so it seems like it should be split pretty evenly.


A while back I bought a an old Bmx bike I'm certain it's a mongoose but I'm not sure what year I plan to restore it but I'd like to know exactly what it is first. Can anyone help with serial number reading. The number is sy6h00o680 it's late 90s I believe

This is a canonical question that will hopefully encompass all of the questions we get asking us to determine what year a bicycle was manufactured (how old is my bike, how old is my frame, etc.). Each "answer" should address a different way to determine the manufacturing year of a bicycle. To some extent, these will also help you narrow down the model as well as it will tell you what distinguishing features to look at.  The span of answers would include things such as:      Skiptooth cranks Cartridge bottom brackets (BB30/90 etc) Elliptical chainring Quick releases versus contemporary through-axles How the steerer attaches to the fork (quill vs. threadless)  Braking system (especially with mountain bikes: v-brake, direct pull, etc.)   Shifting ramps and pins on cassettes/sprockets and chainrings (versus flat sprockets) Frame material (e.g., shift from tubular steel to use of CF and hydroformed aluminium)  Frame tubing type (e.g. Reynolds 531 tubing introduced around 1934, still used today; Reynolds 501 tubing introduced around 1983). So a frame with an original 501 decal can't be from the 70', 531 decal doesn't help as much because of the range of years produced. Also, see Decals.   *Decals: style/design, amount, placement, color, etc. can help not only determine models, but also year of manufacture. Many changed decal design for the same model bike often yearly, with special/limited editions even more specific. This applies only if decals are original or have been replaced with the identical design. Tubing decals (Reynolds, Columbus, etc.) also changed designs for same tubing made in different years, although the changes aren't made as often, and manufacturers didn't always put tubing Brand decals on every model. Earlier bikes tended to have less fancy, less colorful, less quantity of decals.   Headbadges: most early bikes had actual "badges", often quite detailed and fancy, made of metal, then plastic, and finally just using decals on the headtube. Most bikes lost their metal badges in the 60's and early 70's, although some brands still have actual badges to this day, but in general a real badge indicates an earlier model bike. Dropout style (including the later inclusion of lawyers lips) Presence or absence of CPSC reflectors (USA only) Manufacturing method (shift from lugs to TIG welding, for example)  Number of gears (shift from 2x5 ten-speed to 3x8, 2x9, 1x11, etc.)  Inspection of lug design: pantographs, cut-out, stampings, custom brazing/filing, chrome, fork crow n sweep, etc. Frame/Fork Braze-ons. Race bikes tended have less braze-ons the earlier the year of manufacture. Most 60's racers and earlier had few or none with cable guides/stops, shifters, bidons, etc. being clamp-on. By the 80's if it was clamp-on, it was a sign of very cheap models and most frames had braze-ons for all cables, with multiple bottle and accessory bosses depending on style and use.   and so forth. Please edit this question if you have an answer that isn't in the index above.   A couple of caveats:   A previous owner could have replaced or upgraded components on a bicycle, so this guide only applies to original equipment There is a delay between the introduction of a technology (such as indexed shifting) and when manufacturers start selling products that use it. Low-end manufacturers may continue using technology that is severely outdated (such as one-piece cranks, freewheels, or quill stems) because it is cheaper to do so. A number of bikes are built in a Retro style, but with modern components.  Dutch bikes, trendy coffee cruisers, and beach cruisers may be modern but appear to be 1950s styling.  These tend to have modern rims and brakes as a giveaway.     Note that bicycles.stackexchange does not do valuations of bicycles. How much your bicycle is worth depends on the location of the buyer and seller, how much the buyer wants the bike, etc. etc. etc.


I would like to generate training-data for an image classifier, based on a CAD model. Therefore I would like to position my object in the center of the scene and render it from different positions. Also there is an even bigger object (icosphere) placed in the center and each face of this ecosphere is equipped with a camera. The focus is on the center, where the CAD model is located. Is there any possibility to implement this topic in code form and gain the desired images from different perspectives? The results of this approach can be found the following paper:  I value your feedback, so let me know what you think! All the best and stay healthy Alex

I'm new to Blender. I'm currently working on a 3D reconstruction project using neural networks. I need to create my data set. Therefore I need to render a 3D body scan from different angles and save the images separately. I can render creating cameras manually but once i create a loop for the cameras my output is black images. this is the code i used:   bpy.ops.object.camera_add(view_align=False, location=[0,10,20], rotation=[0.436,0,pi]) bpy.ops.object.camera_add(view_align=False, location=[10,20,30], rotation=[0.436,0,pi])    for ob in scene.objects:     if ob.type == 'CAMERA':         bpy.context.scene.camera = ob         print('Set camera %s' % ob.name )         file = os.path.join('/home/fotofinder/Downloads/tryrender/images', ob.name )         bpy.context.scene.render.filepath = file         bpy.ops.render.render( write_still=True )    If anyone can help to define the proper parameters for the cameras in order to always have the object in the image I would be grateful.


When I run mklink /D "C:\Users\bwilliams\AppData\Roaming\Sublime Text 2" "C:\Users\bwilliams\Dropbox\Sublime Text", I get this error `You do not have sufficient privilege to perform this operation.  Why not? I'm administrator, and just want to create a link in my own Users\bwilliams directory to another folder in my Users\bwilliams directory?  What am I doing wrong here?  Thanks.

How can I grant a particular user the permission to create symlinks in Windows 7?  I've searched through "Group Policy" and Google, but haven't found anything.  On a side note, is there a way to search through everything in Group Policy Editor? The filters only seem to work on particular subtrees. I never actually found anything using the filters.


I want to create a stationary point in the middle of the screen and when the user touches and drags on the screen it should create another point that will follow the users input but will always stay on a fixed distance from the other stationary point. I can easily make it so that the game tells me when the 2nd point is on that exact distance while dragging it around.  public boolean touchDown(InputEvent event, float x, float y, int pointer, int button) {     setPosition(a, b);     return true; }   So basically I want to know how to set the a (x-coordinate) and b (y-coordinate) correctly. Also I'm not sure if this is more of a mathematical problem or does libgdx (or java for that matter) have any nifty things I could use? Any help appreciated.

Given a point (pX, pY) and a circle with a known center (cX,cY) and radius (r), what is the shortest amount of code you can come up with to find the point on the circle closest to (pX, pY) ?  I've got some code kind of working but it involves converting the circle to an equation of the form (x - cX)^2 + (y - cY)^2 = r^2 (where r is radius) and using the equation of the line from point (pX, pY) to (cX, cY) to create a quadratic equation to be solved.  Once I iron out the bugs it'll do, but it seems such an inelegant solution.


I am just wondering what the rules are here regarding making threads about other users, and whether it is considered a professional, or an unprofessional way of encouraging other users to vote bomb them? Particularly using labels such as "Newbie" et cetera? Surely if a person's threads are so bad, then people will vote them down anyway, using their own mind, without a person requiring to make a thread asking other users to vote bomb them? The system here seems to be a good one. But there appears to be a few flaws. Surely the system is broken, if it is ok to go to Meta, make a thread about a newbie, and ask how one can get this newbie suspended, and then get a response that equals "vote bomb them". Surely the system is flawed, if it becomes ok, after that person is suspended, and is ensured that no-one else will find out about their suspension, and after receiving this message "It is a private, confidential communication mechanism between such and such community moderators and users. Our goal is to amicably resolve issues in a constructive way through direct communication. Please note that continuing to persist in problematic behaviors is grounds for timed suspension." they find the moderator that sent them that message posting updates of the persons whereabouts in order to encourage people to follow him and farther vote bomb him? Surely the system is flawed if the newbie after being sent that letter of confidentiality, then goes to Meta, to find his suspension being discussed by other users in comments sections? Is this supposed to be self moderation? Surely this is "abuse" of self moderation? I apologise if you do not like my opinion.

I  and a user was rude to me in a comment and in an answer. Even though I can't downvote, that answer got -5 and it was automatically deleted. I want to complain about that user. How can I do that?


Yesterday i try to install some package and i get error about runit . So i search on Internet and a fix was to   sudo dpkg --force runit   i did it but as i tried today   sudo apt-get update   i got this errror  E: dpkg was interrupted, you must manually run 'sudo dpkg --configure -a' to correct the problem.    But then i tried configuring runit package and here is the error i get  start: Unable to connect to Upstart: Failed to connect to socket /com/ubuntu/upstart: Connection refused dpkg: error processing package runit (--configure):  subprocess installed post-installation script returned error exit status 1 Processing triggers for man-db (2.7.0.2-5) ... Processing triggers for fontconfig (2.11.1-0ubuntu6) ... Errors were encountered while processing:  runit   Please help me how to fix this

I am using 15.04.   So I'm working with git and I installed the standard version. I set up the ssh keys and was able to clone one of my repositories to the correct folder. Everything was working great and then I decided it was a good idea to install more packages. I ran sudo apt-get install git-all. I'm looking at error codes now having to deal with upstart.  start: Unable to connect to Upstart: Failed to connect to socket /com/ubuntu/upstart: Connection refused No apport report written because the error message indicates its a followup error from a previous failure. dpkg: error processing package runit (--configure):  subprocess installed post-installation script returned error exit status 1 dpkg: dependency problems prevent configuration of git-daemon-run:  git-daemon-run depends on runit; however:   Package runit is not configured yet.  dpkg: error processing package git-daemon-run (--configure):  dependency problems - leaving unconfigured Errors were encountered while processing:  runit  git-daemon-run E: Sub-process /usr/bin/dpkg returned an error code (1)   This is what happens when I even update/upgrade my system. At this point all I'm looking to do is be able to install software and update my current software. Is there any way I can potentially reverse this issue or at least correct it?   Edit: Thankfully this issue was solved only a day or two after it happened. The accepted answer worked perfectly and took care of my issue


I set the xtick-labels to π/2, π and so on. Now because my x-values are small an exponential factor is still drawn under the x-axis. One workaround is to multiply all my values by hand with 1000.  I found an answer how to change the position of this factor , but how to remove it completely?  The following code demonstrates the problem:  \documentclass[border=3mm]{standalone} \usepackage{tikz,pgfplots} \begin{document}     \begin{tikzpicture}         \begin{axis}[             xlabel=$\omega_g$,             axis lines=middle,             xmin=0, xmax=0.021,             xtick = {0, 0.005, 0.01, 0.015, 0.02},             xticklabels={0, $\frac{\pi}{2}$, $\pi$,              $\frac{3 \pi}{2}$, $2\pi$},         ]         \addplot []         table[x=t,y=signal] {         t       signal         0       1         0.01    2         0.02    3         };              \end{axis}     \end{tikzpicture} \end{document}

A chart with data in the range of 200,000 and small difference between max and min values, will be assigned a 10^5 multiplier to the entire axis. This results in the ticks becoming meaningless, since all become 2.   Example:-  \begin{tikzpicture} \begin{axis}   \addplot coordinates {   (100,200001)   (200,200003)   (300,200005)   };     \end{axis} \end{tikzpicture}   When this is plotted the y-axis has 5 ticks, all of which are 2. The y-axis has a multiplier of 10^5. This has effectively removed all information from the graph.  I may use the below to set the explicit value of the tick values but this does not implement change in the display "style" of the axis ticks.  ytick = {200000, 200005, 200010}   I have also tried increasing the precision of the tick label to 5. However this only results in the graph showing labels such as 2.00000, 2.00005, 2.00010 with a 10^5 axis multiplier.  yticklabel style={precision = 5,}   My question is "How do I remove/change this 10^5 multiplier, such that the y-axis ticks are displayed in the form 200000, 200005, 200010.


This is what I have heard from someone who did his PhD at Princeton. Harvard, Stanford, Berkeley, Princeton, MIT, etc. are biased towards accepting candidates who got their degrees from those schools.

Recently, someone analyzed  and found that over half of the professors at the top 51 universities graduated from a top 10 university.  have also brought this up. From my personal observations, most schools do hire graduates from better ranked schools.  Is this because of the competitive job market? We have so many good applicants, we have to narrow it down some how! Or is it simply that these schools produce the most PhDs? Has this always been the case? How rare are exceptions to this? I know of a few people who graduated from a top 75 school and got hired at a top 50 school. But what about bigger gaps? The top 10 schools seem to just swap graduates, do they ever hire from a 50+ ranked school?  Update 2018: I have accepted a tenure-track position at a top 75 department at an R1 university immediately after graduating from an unranked department at an R2 university. It does happen! This may or may not generalize to other fields and countries.


Prove that $ 3 =\sqrt{1+2\sqrt{1+3\sqrt{1+4\sqrt{...}}}}$   According to the source, this can be done easily like $$(x+1)^2 = 1+2x+x^2$$ $$(x+1)^2 = 1+x(x+2)$$  But how to continue and prove this?

How does one prove the following limit? $$   \lim_{n \to \infty}   \sqrt{1 + 2 \sqrt{1 + 3 \sqrt{1 + \cdots \sqrt{1 + (n - 1) \sqrt{1 + n}}}}} = 3. $$


Gravity attracts objects which have mass right. We know that light is massless so why does a black hole's gravity attract light?

Light is clearly affected by gravity, just think about a black hole, but light supposedly has no mass and gravity only affects objects with mass.  On the other hand, if light does have mass then doesn't mass become infinitely larger the closer to the speed of light an object travels. So this would result in light have an infinite mass which is impossible.  Any explanations?


While I know there is a hack to prevent MacBooks — 2016 and higher — from starting up when the lid is open, I would like to know if there is a similar hack to prevent a MacBook from powering up when an input device (keyboard or trackpad) is touched or when the lid is open.  I have a MacBook Air (2019) that is running macOS 10.15.4 (Catalina) and it seems to do something that owners of 2016 and newer MacBook Pros mention experiencing: The second you open up the lid of the MacBook, the MacBook boots up without hitting the power button.  This isn’t a completely annoying issue, but I find it to be a bit odd. I have —as well as this  post—that recommends modifying the NVRAM like this:  sudo nvram AutoBoot=%00   And to unwind that you can run this command or reset the NVRAM completely:  sudo nvram AutoBoot=%03   But when I did this, while the machine—indeed—did not initially boot up when the lid was open, pressing any key on the keyboard—and even the trackpad—will make my 2019 MacBook Air start up. So my question is  but I am also asking about the issue where the machine will start up if a keyboard key or the trackpad is pressed.  This seems weird to me: Why have a power button when any touch of an input device will start the thing up?  Is there any way to prevent a MacBook Air (2019) — and possibly 2016 and newer MacBook Pros — from powering up when an input device (keyboard or trackpad) is touched or the lid is open?  Just let me be able to power it up the good old fashioned way by pressing the power button (with Touch ID) that is in the upper right-hand corner of the keyboard.

My new MacBook Pro powers on automatically when the laptop lid is opened.  Can I disable it ? If yes, then how to do it ?


I understand how time (space/time) is perceived according to the theories of relativity, but I still don’t understand: Did the Big Bang occur 13.8 billion years ago or is it occurring relative to us 13.8 billion years ago? Is the day I was born occurring x years ago relative to me or did it occur x years ago? Is the day I die occurring x years from now, or will it occur only in x years from now? When using the word relative in my examples, I am not necessarily meaning it in the sense of special relativity.

This is an attempt to gather together the various questions about time that have been asked on this site and provide a single set of hopefully authoritative answers. Specifically we attempt to address issues such as:   What do physicists mean by time? How does time flow? Why is there an arrow of time?


I am trying to install ubuntu 14.4 on a computer (actually into QEMU emulator) which does not use unity or any GUI, and only a command line which looks like the "terminal" application in fullscreen. I checked out , but I do not want server features, just ubuntu desktop features without the desktop. How can I do this, or possibly is there a way to remove the "server" from ubuntu server? EDIT: Ubuntu server appears to be only available for 64-bit machines. I am planning to run it within QEMU Emulator on a 32-Bit Toshiba Satellite machine running Ubuntu Desktop 14.4.

I've been thinking a lot about this lately and haven't been able to find any good documentation online that explains this:  When installing Ubuntu Server, I can choose between Minimal system and Minimal virtual machine by hitting the F4 button at the install screen.  Why should I choose one over the other?


I would like to call method of MainFragment.java from MainActivity.java  Here what I have tried:  MainActivity.java  MainFragment mainFragment;  ........  mainFragment = new MainFragment();  .........  mainFragment.deom();   MainFragment.java  public void deom() {      Toast.makeText(getActivity(), "Demo", Toast.LENGTH_LONG).show();  }   Log  java.lang.NullPointerException at android.widget.Toast.<init>(Toast.java:93) at android.widget.Toast.makeText(Toast.java:241) at com.example.x.b(Unknown Source) at com.example.MainActivity.onOptionsItemSelected(Unknown Source) at android.app.Activity.onMenuItemSelected(Activity.java:2633) at android.support.v4.b.ao.onMenuItemSelected(Unknown Source) at android.support.v7.app.t.onMenuItemSelected(Unknown Source) at android.support.v7.view.n.onMenuItemSelected(Unknown Source) at android.support.v7.view.n.onMenuItemSelected(Unknown Source)   May I know where I am doing mistake ? What I have missed ? Why I am getting NPE.

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'm looking for a roughly equivalent tool in QGIS to the Repair Geometry Tool in ArcGIS Desktop. When I run some common vector processing tools in QGIS, I occasionally run into invalid geometry errors and have yet to find a quick/easy fix that doesn't involve manual editing.   Is there an automated process that I can use?

I am working on ownership data at a US county level. I have one shapefile per county that contains thousands of tax parcels. I need to dissolve the polygons representing parcels owned by the same individual. When the shapefile is not clean, the "Dissolve" tool in QGIS doesn't seem to work, it freezes. I have to fix the geometry validity issues first using the "Check Geometry Validity" tool. However, I have sometimes hundreds of errors. It takes a lot of time to fix them manually. Is there any other strategies that could save me some time?  I am using QGIS 2.4.0.


After installing sumo-0.32.0 on Ubuntu 16.04 LTS, I noticed that SUMO folder doesn't contain a bin directory!  The SUMO folder I checked is in the path: /usr/share/sumo Is this the right sumo home directory, and how to set its environment variable step by step?  I installed sumo as indicated by its web page using the following three commands:   sudo add-apt-repository ppa:sumo/stable  sudo apt-get update  sudo apt-get install sumo sumo-tools sumo-doc

I'm trying to set up Apache Tomcat on my pc, and it wants me to set up an environment variable for CATALINA_HOME.  Does any know how to do this?


I'v created a custom post type with this code :  register_post_type('Villes',     array(         'labels' => array(             'name' => __('Villes'),             'singular_name' => __('Villes'),         ),                     'public'      => true,         'has_archive' => true,         'rewrite'     => array('slug' => 'villes'),         'taxonomies'  => array( 'category' )      ) );   As you've noticed I've activated Categories for the post. This is the structure on my categories :    cat1   sub1 sub2  cat2   I've created a custom post in the sub2 category, what should I do so the permalink of the post is mysite.com/cat1/sub2/post-slug (and not mysite.com/villes/post-slug)

I know people have asked this before and have gone as far as adding the custom post type, and rewrite for permalink.   The problem is I have 340 existing categories which I would like to continue using. I used to be able to see /category/subcategory/postname  Now I have the slug of customposttype/postname. Selecting the category no longer shows up in permalink...I've not changed the permalink setting in admin to anything different.  Is there something I'm missing or need to add to this code?  function jcj_club_post_types() {     register_post_type( 'jcj_club', array(         'labels' => array(             'name' => __( 'Jazz Clubs' ),             'singular_name' => __( 'Jazz Club' ),             'add_new' => __( 'Add New' ),             'add_new_item' => __( 'Add New Jazz Club' ),             'edit' => __( 'Edit' ),             'edit_item' => __( 'Edit Jazz Clubs' ),             'new_item' => __( 'New Jazz Club' ),             'view' => __( 'View Jazz Club' ),             'view_item' => __( 'View Jazz Club' ),             'search_items' => __( 'Search Jazz Clubs' ),             'not_found' => __( 'No jazz clubs found' ),             'not_found_in_trash' => __( 'No jazz clubs found in Trash' ),             'parent' => __( 'Parent Jazz Club' ),         ),         'public' => true,         'show_ui' => true,         'publicly_queryable' => true,         'exclude_from_search' => false,         'menu_position' => 5,         'query_var' => true,         'supports' => array(              'title',             'editor',             'comments',             'revisions',             'trackbacks',             'author',             'excerpt',             'thumbnail',             'custom-fields',         ),         'rewrite' => array( 'slug' => 'jazz-clubs-in', 'with_front' => true ),         'taxonomies' => array( 'category','post_tag'),         'can_export' => true,     ) );


So, I only bought Terraria less than a week ago, and I am really happy because I am loving the game and I am learning fairly quickly, so here is my question. Can items despawn in Terraria? This would be good to know, if ever I decided that hardcore difficulty was a good idea. I know that monsters, and even bosses can, but hopefully dropped items, including coins dropped upon death won't ever despawn over time. How does this mechanic work?

How long do dropped items persist in Terraria?  I somehow dropped a gold pick in a corner I couldn't get to, and when I went to retrieve it, it had disappeared.  Under what conditions do dropped treasure disappear?


Edit: Replaced black hole with neutron star, thanks to safesphere for his comment.   We're told that tiny volumes of matter have huge mass in a neutron star. For the sake of argument, if you had a 1cm cube of matter that weighed 1k tonnes and you bought it back to Earth, would the volume still be the same? If that's the case, why can't we create super dense matter in a lab? Or would it just be insanely hot?

Why does there have to be a singularity in a black hole, and not just a very dense lump of matter of finite size? If there's any such thing as granularity of space, couldn't the "singularity" be just the smallest possible size?


I want to allow access to 2 users on one directory. I am trying since days but unable to do so! Let me make it simple for you guys to understand by giving a simple example. But first, Let me tell you that the user named admin should be able to access both the directories.Consider two Directories:   /var/www/directory1 /var/www/directory2   and two users:   user1 user2   I want user1 to access only the directory directory1, user2 to access the directory directory2 and admin to access both the directories! I tried giving ownership to respective directories to the users and the group named admin-group to let admin access both the directories. That didn't work well. I also tried giving write access to the group but failed.  Is it possible to do what I want? If possible, How can I?

I want to stop having to use sudo everytime I work in /var/www. How can I do that? I simply want to put all of my sites into this directory and work with them without too much pain.


Could someone help me with netflix on Ubuntu 14.04 desktop. Pipelight does not work. When I go to the netflix desktop application it opens firefox, and shows the series, but when I click to play a screen appears telling me:    You're almost ready and only need to install the microsoft silverlight plugin.    Pipelight itself is installed and enabled but I saw in the window on the desktop opens netflix portion plugins complements the pipelight appears with this error  Pipelight Error (silverlight5.1)! Something went wrong, check the terminal output libpipelight-silverlight5.1.so application/x-pipelight-error-silverlight5.1   (Error during initialization: pipelighterror-silverlight5.1)   If I open Firefox by other plugins and see the pipelight okay, this error does not appear.

Is there a way to stream Netflix content to my Ubuntu machine?


As Smite/Teleport top is being increasingly popular, I want to know what situations it can be used effectively in.

I saw some top laners who use smite and teleport as spells and (if I'm correct), it's becoming pretty regular and although I don't play as a top laner, maybe when I have to adjust, I know I may find this useful.  My questions are when and who :  When to use it / what are some of the conditions needed since it was told that this strategy isn't always going to be useful in every top laner,  Who are the champions that will really take advantage of this?