I am new to ubuntu and linux world. Where can I see the list of all programs installed in ubuntu ?  Ex: If I want to launch "terminal". I need to click the upper left icon and type "terminal". Where is the icon really located ?  I would like to take a look in the programs installed. Are they separeted by category ? I don't know.  Thanks

I'd like to output a list of all installed packages into a text file so that I can review it and bulk-install on another system.  How would I do this?


By default, the database hostname is localhost after the Postgres has been installed. Can the hostname be changed to something else like localhost\\abc? If yes, how can I do it in Windows/pgadmin? Thanks

How does one edit the 'postgresql.conf' file with the pgAdmin app?  With pgAdmin 1.18.1 on Postgres 9.3.x, when I choose File > Open postgresql.conf I get a file picker dialog. And, yes, I'm connected in pgAdmin as the superuser 'postgres'.  I know I've done this in older versions of Postgres.


Can I remake a game I don't own any copyright to?  There's a online browser game which I played 5 years ago. Some time ago, this game was shutdown because its developer went bankrupt. I want to re-make this game and provide it to Web again. Can I do this? Or there's some copyright problem or something like this?

Recently I started remaking an old game on Unity. Basically I want to remake an old RPG that was released for Playstation 1. I'm not ripping anything from the old game, all the assets are being created by me. I'm creating everything from the scratch, music, 3D models, gameplay however I will keep the (copyrighted ?) names, I will try to create the characters and maps/levels as they were in the original version of Playstation 1 but with better graphics.  I'm not planning on selling it or adding in on a platform like Steam (for obvious reasons, copyrights etc), just giving it for free. But I wanna know when I will finish the development, can I share the game on public with other people so they can download it?  Can the company that made the original game sue me/fine me because of copyrights reasons even though I'm not planning on selling for money?  tl;dr Remake an non-profit game of PS1 from the scratch, can the company that holds the copyrights of the game sue me/fine me?


\documentclass[tikz]{standalone}  \usepackage{pgfplots}  \begin{document}  \begin{tikzpicture}     \begin{axis}[]     \addplot {x^2 - x +4};     \addlegendentry{$\to$}     \end{axis} \end{tikzpicture}  \end{document}      ! Missing control sequence inserted.\inaccessible   \addlegendentry{$\to$}    I wanted to use $\to$ in a legend entry in pgfplots but this leads to an error.  Other math stuff works fine, e. g. \addlegendentry{$\alpha$} works. The solution so far is to encapsulate it with extra pair of curly brackets: \addlegendentry{{$\to$}}.  Is this an expected behavior? What is so special about $\to$?   Edit     There is already a pgfplots bug report:    Solution at the moment (March 2017) is to use \rightarrow.

I was trying to make a table with pgfplotstable and append one csv file to another by \pgfpotstablevertcat. Now I wanted to change the math font with unicode-math, but then I get the error "File ended while scanning use of \pgfplotslistpushback". I am using lualatex from MiKTeX to compile the document. Same problem for xelatex.  What could be the issue? Is it a bug or am I missing something obvious? Here is a MWE which produces the error.  \documentclass{article} \usepackage{unicode-math} \usepackage{pgfplotstable}  \begin{filecontents}{dataA.csv} pH,     concentration 1,      1.5 2,      -0.5 3,      -1.5 \end{filecontents} \begin{filecontents}{dataB.csv} pH,     concentration 4,      -2.5 5,      -3.5 6,      -4.5 \end{filecontents}   \begin{document} \pgfplotstableset{col sep=comma} \pgfplotstablevertcat{\outputa}{dataA.csv} % loads `dataA.csv' -> `\outputa' \pgfplotstablevertcat{\outputa}{dataB.csv} % appends rows of dataB.csv \pgfplotstabletypeset[columns={pH, concentration},fixed zerofill]{\outputa}; \end{document}


I am able to get standard field of parent object in attachment:  SELECT Id, Parent.Name, CreatedBy.Name FROM Attachment   But how to get custom field from parent attachment, something like:  SELECT Id, Parent.Name, CreatedBy.Name, Parent.Custom_Field__c FROM Attachment   How can I achieve this?

Please Help me...  Account sObject is Parent of Attachment. Now I want to bring Read-only Field Custom field (isReadOnly__c).  SELECT Id, Name, Account.isReadOnly__c FROM Attachment   How It Gets ?  Thanks in Advance  Manu


Normally, when I browse a site in desktop mode on my iPhone, I can tap a comment and the upvote and flag options will appear:    However, this doesn't work when reviewing from mobile. I can tap or long-press whatever I want, but the upvote/flag options won't appear.  This is not really a duplicate of ; that's simply a  which has never been updated to  (so I do understand the close votes). For proof, see the screenshot below:    (and flagging is possible as well, by the way)

I'm still becoming increasingly confused as to why we can't do or see certain things (really, just about anything except for answer a question) from the Review interface.  Today, it's comment voting.  I came across a question in the close queue where another person had already left a comment that clearly described why the question should be closed.  Sometimes, I'll come across other questions where a commenter has also clearly stated what can be done to improve this question so that it will either not be closed or will be a good candidate for getting re-opened.  Often times, in either case, the thread is still worth my close vote because it is either off-topic, low quality, or missing out on some other SE criteria, and it does not contain enough detail for me to feel confident that I can edit it into a good question that is still valuable to its original author.  I personally feel that, in most cases, it is our responsibility to the question author to give them feedback if we are going to down-vote or vote-to-close their question.  Sometimes, the feedback is clear enough in the close reason but this is only visible after the final vote - and even then, only the option selected by the majority is shown.  For instances where I'm giving a down-vote, or I'm one of the first-through-fourth people voting to close, the comment space is my only real option for giving feedback to the author.  Regardless, I feel that providing feedback to the author is essential in helping them to learn how to write better questions, write questions that better fit the StackExchange model, and get answers that are both useful to them and the community.  However, in cases where another person's comment already clearly and thoroughly relates my concerns regarding the post, it's often preferable that I up-vote the existing comment instead of leaving my own, redundant comment to clutter up the thread.  This is not currently an option from within the Review interface.  Interestingly enough, I'm allowed to leave a comment but I'm not allowed to vote on existing comments.  If I want to vote on an existing comment, I need to follow one of two processes - the choice between which is pretty much determined by the first step in each:   Remember that the Review interface will immediately leave the question when I choose an action option. Open one of the links to the question in a new, background tab in my browser. Choose my action for the question.   If necessary, choose the reason for my action. If necessary, select other options (i.e.: duplicate question) to complete the action.  Switch to the question's tab. Vote on the comment. Close the question's tab and go back to reviewing, or doing whatever else I was going to do.   OR   Forget that the Review interface will immediately leave the question when I choose an action option. Choose my action for the question.   If necessary, choose the reason for my action. If necessary, select other options (i.e.: duplicate question) to complete the action.  Open a new browser tab with the main site interface. Search for and open the question. Vote on the comment. Close the question's tab and go back to reviewing, or doing whatever else I was going to do.   Each of these workflows has four steps (italicized), plus associated page loading times, that I would not need to go through if the option to vote on a comment was simply included in the Review interface.  So, for the sake of our time and sanity - the savings of which, I believe, is the primary goal of this interface in the first place - please add or restore this functionality.


I do factorization by just plugging in simple numbers to check whether they are factors, using long division and also using synthetic division. But, how to do it in the case of complex equations. For eg: Factorize $x^6+5x^3+8$  Putting $v=x^3$ I get $v^2+5v+8$. But, this equation has complex roots. So, how to continue?

I wanted to know, how can I factor $x^6 +5x^3 +8$, I have no idea. Is there any method to know if a polynomial is factored. Just some advice will do.  Help appreciated.  Thanks.


A related post . In which the author claimed, if $X_{i}\sim N(\mu,\sigma^2),i=1,\cdots,n$ are iid then      $$\frac{(n-1)s^2}{\sigma^2}\sim \chi^2(n-1)$$   in which $s^2$ is the unbiased sample variance. i.e. $s^2=\frac1{n-1}\sum(X_i-\bar X)^2$ where $\bar X=\frac1n\sum X_i$.  I want a proof of it. But I can't do one on my own. In fact, contrary to my initial suspicion that $X_i-X$ are uncorrelated, I actually got \begin{align} \mathsf{Cov}\,(X_i-\bar X,X_j-\bar X) &=\mathsf{Cov}\,(X_i,X_j)+\mathsf{Var}\,(\bar X,\bar X)-2\mathsf{Cov}\,(X_i,\bar X)\\ &=0+\frac1{n^2}n\sigma^2-2\frac1n\sigma^2\\ &=-\frac1n\sigma^2\ne 0 \end{align}  So where does the Chi square come from?

The statement  The sampling distribution of the sample variance is a chi-squared distribution with degree of freedom equals to $n-1$, where $n$ is the sample size (given that the random variable of interest is normally distributed).    My intuition  It kinda makes intuitive sense to me 1) because a chi-square test looks like a sum of square and 2) because a Chi-squared distribution is just a sum of squared normal distribution. But still, I don't have a good understanding of it.  Question  Is the statement true? Why?


I am interested in obtaining (or building myself) a version of the Linux kernel that has absolutely no virtual memory and none of its attendant overhead. No swap file, no nothing.  What are my options?

I am using Debian sid, hard drive formatted with ext4, running on linux 3.1  I remember on previous linux versions (maybe before 3.0), if I run out of memory, and swap is not enabled, programs will usually crash. This is perfect for my environment: simple web browsing with no critical operations. That is, if I accidentally run across a bad website which uses up too much memory, it just crashes without rendering my terminal unusable.  But in my current setup, the computer hangs with violent I/O throughput in the background. iotop reveals kswapd0 to be the culprit, which means it is due to swapping. After using swapon -s to determine any swaps that were enabled, I used swapoff -a to disable all swaps and swapon -s again to confirm that all swaps were disabled.  Then I tried maximizing my memory usage again. Alas, the behavior I expected didn't happen. Instead, kswapd0 tries over and over to swap out the RAM and fails as there is no swap space. Because it never gives up, my computer is locked in eternal I/O heavy freeze, bad for my disk's health.  Am I doing something wrong in trying to swapoff -a? Why is the behavior different than what it used to be (probably pre-3.0 times)?


I want to call my equation $NS_\alpha$ in such a manner that rather than      (1.1)   the equation shows up with      ($NS_\alpha$)

When I have equations, as in  \begin{equation} ... \end{equation}   Can I arbitrarily assign the numbers to the equations? Instead of the usual order (1), (2), (3), ..., I'd like something like (1), (2.1), (2.2), (2.3), (3.1), (3.2), (4), ...


Given a homomorphism $f:G \rightarrow H$, $G$ finitely generated, what can you say about the order of $g_i$ and $f(g_i)$?   I've thought about this question for a while but haven't come to a conclusion.  If we consider the natural homomorphism from $\mathbb{Z}$ to $\mathbb{Z}_3$, the order of 1 in $\mathbb{Z}$ is infinite but the order of 1 in $\mathbb{Z}_3$ is only $3$. Therefore, the order of $f(g_i)$ can be less than that of $g_i$. But can't it also be greater? If not, wouldn't it be impossible to construct homomorphisms from a group of order $n$ to a group of order $p$ where $p > n$?  Thanks.

Let $\phi: G \to H$ be a group homomorphism, and let $g$ be an element of $G$. Show that the order of $\phi(g)$ divides the order of $g$.


I've been trying to derive the result of the following dot product in position space: $\langle p|x\rangle$. The information I'm supposed to be using: i) Any state can be written as a linear combination of the basis vectors: $|p\rangle=\sum_i a_i|i\rangle$ ii) The dot product between two functions is given by: $\langle f|g\rangle=\int_{-\infty}^{\infty}f(x)^*g(x)dx$ iii) The eigenstates of the operator $\hat{x}$ are $|x\rangle$. iv) I must use the eigenstates of p and x: $\langle p|x\rangle =\int_{-\infty}^{\infty}\psi^*_p(x)\psi_x(x)dx$ v) The representation of the momentum operator is $\hat{p}=-i\hbar\frac{\partial}{\partial x}$ vi) Functions can be represented as $\psi(x)=\langle x|\psi\rangle$. Well, I'm pretty much struggling to start to solve this problem and it seems that my lack of understanding regarding the representation of an eigenstate in a base might have to do with it. What I thought first was: Using (iv) and (vi) I got $\langle p|x \rangle =\int_{-\infty}^{\infty}\langle \psi_p|x\rangle ^*\langle x'|\psi\rangle dx{} dx'$ , where $|x\rangle \langle x'|$ should be an operator. However, I'm stuck from this point forward. I don't know how to write the eigenstates in a way that helps my attempt. What is wrong with my approach?

I'm curious whether I can find the overlap $\langle q | p \rangle$ knowing only the following:   $|q\rangle$ is an eigenvector of an operator $Q$ with eigenvalue $q$. $|p\rangle$ is an eigenvector of an operator $P$ with eigenvalue $p$. $Q$ and $P$ are Hermitian. $[Q,P] = i \hbar$.   I'm asking because books and references I've looked in tend to assume that $Q$ is a differential operator when viewed in the $P$-basis, then show that it satisfies the commutation relation. (I haven't read one yet that proves that the form given for $Q$ is the only possible one.) I've heard, though, that we can work purely from the hypothesis of the commutation relation and prove the properties of $Q$ and $P$ from it.


We all know that $0.99999...=1$  So does that imply $[0.99999...]=1?$  Or do we consider it as $0?$  My doubt is: any gif of the form $[0.xyz...]=0$. If $[0.99999...]=1$ won't that be contradicting?   There isn't much clear explanation in the previous post.  Here $[.]$ is the greatest integer function. I couldn't find a post containing this query on MSE. Please help :)

Are the floor functions of $0.999\cdots$ and 1 equal?  It is true that $0.999\cdots=1$ but how does one justifies the integer part of $0.999\cdots$ being 1 , where it is not, or alternatively without using $0.999\cdots=1$ how can we show that  $\lfloor0.999\cdots\rfloor = \lfloor 1 \rfloor$ ?


This question has been asked many a times on physics stack exchange but I can't understand this in simple terms. This is a definition I got online:  The third law states that all forces between two objects exist in equal magnitude and opposite direction: if one object $A$ exerts a force $F_A$ on a second object $B$, then $B$ simultaneously exerts a force $F_B$ on $A$, and the two forces are equal in magnitude and opposite in direction: $F_A = −F_B$.  My question for this is that if a force is applied to body $B$ by body $A$, and the magnitude is $10$N, body $B$ is applying the same magnitude of force against body $A$. So, the forces should cancel out and motion won't be possible in that case as Newton's first law states that there should be an unbalanced force for bringing a body from rest to motion. One thing people are answering is that they are on different body but they are also in different direction so force should cancel out as it is simultaneously exerted on the two bodies.

Given Newton's third law, why is there motion at all? Should not all forces even themselves out, so nothing moves at all? When I push a table using my finger, the table applies the same force onto my finger like my finger does on the table just with an opposing direction, nothing happens except that I feel the opposing force. But why can I push a box on a table by applying force ($F=ma$) on one side, obviously outbalancing the force the box has on my finger and at the same time outbalancing the friction the box has on the table? I obviously have the greater mass and acceleration as for example the matchbox on the table and thusly I can move it, but shouldn't the third law prevent that from even happening? Shouldn't the matchbox just accommodate to said force and applying the same force to me in opposing direction?


So I monitor some logs (/var/log/apache2/error.log) with the command tail -f, and only print the errors (grep ':error'). I combined both of these in a script (namely, watch_error_log.)  NB: I am part of the adm group.  So far so good.  But when I attempt more useful tricks, it won't work, such as :  $ while read APACHE_DEBUG_LOG; do echo "$APACHE_DEBUG_LOG"; done < <(watch_error_log) or $ watch_error_log | while read DEBUG_LOG_APACHE; do echo "$DEBUG_LOG_APACHE"; done;   Of course, my goal is not to ECHO the output. But If echo won't work, I know it is not because of the other program I want to use.  Why doesn't it work, and how can I make this work ?  After reading , I tried to add --line-buffered and everything's good.

I want to monitor a file. So I have tailed a file using below command, to execute a script per line.  tail -3f logfile.log | grep "action.*add" | sed -u -e "s/^/'/" -e "s/$/'/" | xargs -L 1 -P 5 bash testscript.sh   But it seems that script is not getting executed.  I observed that grep is not giving any input for next pipe.  When I tried,  tail -3f logfile.log | grep "action.*add"   it worked. But when given next filter like sed, grep, xargs etc. It didn't worke like the one shown below.  tail -3f /var/tmp/rabbitmq-tracing/logfile.log | grep "action.*add" | grep add    Please help me to know why this is happening and how to overcome this.    Edit 1: Basically anything like below should work and it was working previously. Confused why it is not working now.  tail -f file.txt | grep something | grep something | grep something     EDIT 2: Output line after first grep will be a json string like below. And I want to give this line as input( enclosed in single quotes) to bash script.  {"twNotif": {"originator": "api", "chain": "test", "txId": "08640-0050568a5514", "version": "1.0", "msgType": "api", "twData": {"api": {"hostId": "007bdcc5", "user": "test", "cmdTxt": "100599"}}, "action": "add", "store": "test", "msgTime": 1467280648.971042}}


I'm creating an iOS app who will have to stop the standby timer.  I mean the timer who put the device in standby after 60 seconds that a user does not touch the screen.  How can I do it?  Thanks

how to set iPhone device to stay active ( to not lock ) while my app is running ? Any idea


Is there a simple way to install a list of packages in ?  I’ve tried the command line arguments with no success.  For example I’ve tried the following with no success in uninstalling wget.  ./setup-x86_64.exe -q -x wget

I'm a blind computer user that uses Cygwin.  The installation program isn't very accessible: upgrading, installing, and removing specific packages is quite hard to do since you have to use simulated mouse keystrokes to click and scroll.  Is there a way to either manually install/upgrade packages or install/upgrade them through the command-line?


I already checked other posts in this area, but still couldn't get a fit to my issue: I have the following preconditions:  Software: preferred SPSS v21, possibly R Sample size: 5655 (will get around 8x times larger in 2 weeks, but I already want to find out statistical pitfalls) DV: binary; 1 = success, rest 0 = fail - sales conversion IV1: categorical; 5 different conditions - different designs IV2: categorical; 3 different conditions - different discount (0,5,10)  and the following problem:  DV = 1 has only 36 cases. IV2 is naturally related to DV, since one of the 3 conditions of IV2 is only applied when DV = 1. Meaning for all DV = 0, IV2 will also equal 0. Conditions of IV1 are randomly assigned to each case. Essentially, I want to find out whether IV2 is a moderator of IV1 -> DV, however, SPSS gives me very strange pseudo-R²s, odds ratios and so on.  After googling I found out it might be a problem of quasi-complete separation. Subsequently, I tried to run Firth logistic regression in SPSS, which never stopped running and in R, which gave me the following error:     Error in chol.default(x) :    the leading minor of order 15 is not positive definite   Such that I have the following questions:   is my issue solely related to the sample size? how can I fix the leading minor error? how can I approach the problem in general (methods)?   Additional info: The different discounts (IV2) are applied to a specific set of products (let's call them set A (0 discount), set B (5 discount) and set C (10 discount)).  Now a visitor comes and is randomly assigned to one of the categories of IV1, which is effecting how A, B and C are displayed to the visitor.  It is only tracked to which category of IV1 the visitor was assigned and which product (from set A, B, C or none of them) was purchased.  I only want to find out the conversion rate of A, B and C and especially which category of IV1 predicts a higher conversion. On top I assume the discount (IV2) to have a moderating effect on the effects of IV1.  I know its probably not optimal to do it like this, but it was not possible in another way. Maybe my reasoning is incorrect, but I hoped to test the above for a moderation effect.   I ran a bayesglm today, it indeed drove down the odds ratios, so that is already a little success, although the results are mostly insignificant, which is probably due to the small sample size. However, I am not even sure whether the bayesglm applies to my situation. Further, I am unsure about the prior means and scales which I am trying to understand at the moment. Any feedback of how I can approach my situation is welcome, thanks!

I'm trying to predict a binary outcome using 50 continuous explanatory variables (the range of most of the variables is $-\infty$ to $\infty$). My data set has almost 24,000 rows. When I run glm in R, I get:  Warning messages:   1: glm.fit: algorithm did not converge   2: glm.fit: fitted probabilities numerically 0 or 1 occurred    I've read the other responses that suggest perfect separation might be occurring, but I'm confident that isn't the case in my data (though quasi-complete separation could exist; how can I test to see if that's the case?). If I remove some variables, the "did not converge" error might go away. But that's not always what happens.  I tried using the same variables in a bayesglm function and got the same errors.  What steps would you take to figure out exactly what's going on here? How do you figure out which variables are causing the problems?


I need to solve the following problem.   Show that if $f$, $g$ : $\mathbb R$ → $\mathbb R$ are continuous, periodic and $\lim_{x→\infty}$ $(f(x) − g(x)) = 0$, then $f = g$.  I have only used the definition of convergence so far. (Unfortunately, I couldn't go further for almost an hour.) For all $\epsilon$ there exists $ r\in \mathbb R$ such that $|{f(x)-g(x)}|\le \epsilon$ for all $x\geq r$  will you give me some hint?

If $f(x)$ and $g(x)$ are two periodic functions, that is, $f(x+T_1)=f(x)$ and $g(x+T_2)=g(x)$ for every $x \in \Bbb R$. Now that $\displaystyle\lim_{x\to\infty}(f(x)-g(x))=0$.  Conjecture: $f(x) \equiv g(x)$.


If someone has two master of science degrees in math and computer science, when writing the degrees in abbreviation as "M.S. in math and in CS", how can we write its plural form, "M.S.' in math and in CS", or "M.S.'s in math and in CS"? Thanks.

Does it indicate a possessive adjective or just a plural noun? If noun, why it is not CPUs (without apostrophe)?


In Breaking Bad, part of Walter's money got absorbed by the Gray Matter corporation that will be later handed out to Walter's family.   But what happens to the remaining money he has made?

So, Breaking Bad has finished.       In the final episode Walt killed Jack, when he started to talk about money.   But where is Walt's money, which Jack has stolen?


I am trying to implement a convex decomposition and I need to find the convex vertex on a mesh. Is there a algorithm that I can use to find the convex vertex on a mesh.

I'd like to be able to decompose a concave mesh into a set of convex meshes for 2 reasons:   Transparent rendering Physics shapes   Is there an algorithm that takes a set of triangles (concave) as input and outputs a number of sets of triangles (convex)?  I'd like it to not fill in the holes between parts of the original mesh.  I've already come across a small idea: find all the concave edges, and split the meshes along the edge loops.  Am I on the right track?  How could I implement this?


$(x_n)_n$ is a sequence defined by the relation: $x_{n+2}=|x_{n+1}-x_{n-1}|$ for $n\geq1$ and $x_0,x_1,x_2$ are non-negative integers, not all three equal 0. I think this sequence is periodic, so here is my question: is it true and if yes which is the period? Thank you!

How to show that the sequence $$x_n, n \geq 0, x_{n+2}=|x_{n+1}-x_{n-1}|, n \geq 1$$ with $x_0, x_1, x_2$ positive integers, not all null,  is periodic?  I tried to pick up the square but obtained equalities not helped.  Thanks so much for any suggestion.


I have found many codes through which equations can be aligned in the left but the problem is it assigns either a single number to all the equations or no numbering at all. I want something like fleqn or falign that can retain the auto-numbering feature of eqnarray.  For example:    \documentclass[fleqn]{article} \usepackage{amsmath} \begin{document}  \begin{equation} \begin{aligned} &A = B + C + .... \\  & A^\prime  = B^\prime + ...\\ &D  =  E + F ...\\ \end{aligned} \end{equation}  \end{document}     It assigns a single number to the whole set of equations, but I want numbering for individual equations and I don't want to assign numbers manually, it should be automated. Like when we use eqnarray.

Is there a way possible to imitate the align environment for math mode commands, without having all writing being placed toward the center on the output page?  MWE:  \documentclass{article} \usepackage{mathtools}  \begin{document} \begin{align*} \cos\theta_1 \cos\theta_2-\sin\theta_1\sin\theta_2 &= \cos(\theta_1 +\theta_2) \\ \sin\theta_1 \cos\theta_2 + \cos\theta_1 \sin\theta_2 &= \sin(\theta_1+\theta_2) \end{align*}  \end{document}


How can I track down why an email is not generated from my new web site when I click Contact on the Contact page?  I turned on maillog and devel. What I get is      maillog =>         ... (Array, 6 elements)  ... (Array, 6 elements)  Subject (String, 23 characters ) [Website feedback] test From (String, 22 characters ) sam.stamport@gmail.com To (String, 22 characters ) sam.stamport@gmail.com Reply-To (NULL) Header (Array, 7 elements) Body (String, 128 characters ) admin (http://columbiablooms.org/users/admin) s...      Krumo version 0.2.1a | http://krumo.sourceforge.net     [Click to expand. Double-click to show path.] Called from     /home5/columck5/public_html/sites/all/modules/maillog/includes/maillog.mail.inc     , line     90  Your message has been sent.   Error message:     Unable to send e-mail. Contact the site administrator if the problem persists.

When my web form is filled and submitted, I get redirected to a page that says:     Thank you for submitting.   but theres a red warning box there that says:     Unable to send e-mail. Contact the site administrator if the problem persists.   I think its the SMTP server, but I don't know how to fix that.


I'm solving a physics question, and i just encountered some question i had no idea how to start, i just got the right answer and inside it it has something in math i never thought possible,  I know that the integral of $a$ (acceleration) by $t$ (time) will give me $v$ (velocity), I also know that the integral of $v$ by $t$ will give me $r$ or $x$ (the movement vector). I know that the derivative of $x$ will give me $v$, and the derivative of $v$ will give me $a$.  I just saw these few lines:    I somehow understand that you can replace $a$ with dv/dt because it's basically the same, but i have no idea how you can multiply the dt in the left sector of the equation, what does it mean?  I always thought that dx is basically saying 'Derivative by x' i never thought it's something "real" you can actually multiply and use basic math with...  Hope you could give me some idea about it, thanks!  In other answer i found this as the answer to "What does $dx$ mean?":     $dx$ does not mean anything. It's just a syntactical device to tell you the variable to differentiate with respect to or the integration variable.   This is exactly why i'm asking, because how can you multiply $dx$ in another thing if it's only a syntactical device?

$dx$ appears in differential equations, such us derivatives and integrals.  For example, a function $f(x)$ its first derivative is $\dfrac{d}{dx}f(x)$ and its integral $\displaystyle\int f(x)dx$. But I don't really understand what $dx$ is.


I have a bunch of Time Machine archives for old computers I no longer have. I want to encrypt these archives. Can that be done using a different computer than the one that was backed up? I have looked that the tmutil man-page and found a couple of interesting options there: inheritbackup - seems to make it possible to use the TM-destination for machine A for machine B. However, there is a caveat in the instructions: Inheriting is typically only one step in the process of configuring a backup for use by a machine. You may also need to use setdestination, associatedisk, or both, depending on the situation. Since this is backup data I don't want to lose or corrupt I am a bit hesitant to experiment (I have copies but if I perform a couple of operations and everything looks fine and I therefore delete my copies just to, a year from now, realise that I broke something I won't be too happy...). Would be nice with a HOWTO or step-by-step guide, if possible.

I have a couple of old Time Machine backups (for computer A and B) that are stored unencrypted on an unencrypted drive. I would like to encrypt them for archival purposes but they need to remain working with TM (e.g. browse using the TM interface, restorable to a new computer using TM and so on). I followed the instructions at  but since A and B are long gone I used computer C. That didn't work out very well, at the final step, instead of starting to encrypt I got this message:  How can I encrypt an old TM backup when I no longer have access to the machine that was the source for that backup?


Update  With kernel 4.4.0-81 it seems to work well again, without myself doing anything extra to fix it.    Everything was working fine until a little more than a month ago, there were multiple kernel updates and Nvidia driver updates during that period so I'm not sure which one caused this problem.  I get the distortion below in the screen after starting the machine from standby (goes away if I restart/log out and log back in), it's shown around any window that is not maximized, around dialog boxes, around menus, basically around any edge on the screen.  I'm currently running kernel 4.4.0-77 and Nvidia driver from the package nvidia-375    PS: switching to the other driver causes other problems, and this one was working very well before this issue, and it had been running properly for months before this problem started happening.

NB: Nvidia has released an official fix; please see ,  and/or .  Upon waking up Ubuntu 16.04 from Suspend, the following graphical glitches appear around all windows, context menus, and similar:      This is currently known to affect the following NVIDIA cards running the proprietary drivers:  NVIDIA GeForce 610M, driver version 375.39, 340.102 NVIDIA GT 630M, driver version 375.39 NVIDIA GTX 650, driver version 375.39 NVIDIA GT 740M, driver version 378.13 NVIDIA GTX 745, unknown driver version NVIDIA GTX 850M, driver version 375.39, 378.13 NVIDIA GT 940M, driver version 375.39 NVIDIA GTX 950M, unknown driver version NVIDIA GTX 960M, driver version 378.13 NVIDIA GTX 970, driver version 375.39 NVIDIA GTX 970M, driver version 375.39 NVIDIA GTX 980 TI, unknown driver version NVIDIA GTX 1060, driver version 375.26, 375.39, 378.09 NVIDIA GTX 1070, driver version 378.09  The above above list has been sourced from reports from other users here on AU,  thread, and  thread. NB: This is be no means an exclusive list. It probably effects nearly all Nvidia cards.  Furthermore, this issue has been replicated on a clean install where the only change was a software update and the installation of the latest NVIDIA drivers.  What is going on, and how can it be resolved?


I'm traveling from Istanbul to San Francisco via Toronto with Air Canada (for both) and I'm wondering if I have to get my luggage and head to the customs in Canada?   Currently holding a Turkish passport and I got a transit visa for Canada. Also, the time between two of the flights is about 1 hour and 50 minutes.  My flights:   Istanbul to Toronto (Air Canada)   <1 hour and 50 minutes between flights>  Toronto to San Francisco (Air Canada)  Thanks (:

I have an upcoming trip where I will be flying to and from Copenhagen, through Toronto.  I notice that my departure and return gate in the Philadelphia airport is not in the international terminal.  Where will I clear customs?


Javascript Object.keys(my_obj) return the keys (ie enumerable property) of my_obj in an array.  But looping in Object.keys(my_obj) array return the methods of my_obj.  Does somebody understand this behaviour ?    Object.prototype.log_key = function() {   keys = Object.keys(this)   console.log('log Object.keys() array return enumerable property', keys)   for (const k in keys) {     console.log('loop in Object.keys() array return method', k)   } }  var my_obj = {   testkey: 'testvalue' }  my_obj.log_key();     Output:   log Object.keys() array return enumerable property [ 'testkey' ] loop in Object.keys() array return methods 0 loop in Object.keys() array return methods log_key

I've been told not to use for...in with arrays in JavaScript. Why not?


The older fsociety dude with the specs, that recruits Elliot on the train.. And pushes Elliot off the pier onto the rocks or whatever it is that happened. Is he real,  Elliot's alter ego? Or some kind of hallucination? If he is just some kind of mental manifestation, is Elliot actually aware of it?  Clues:   He doesn't seem to have a name, despite playing a pivotal role in the plot, and being a crucial part of the story. Nobody seems to mention him, despite the fact that he appears to be in charge of fsociety's whole operation. The accident gets treated like a suicide attempt by the hospital staff, the psychologist, and Elliot himself. Elliot will speak directly to the viewer, mention our apparent non-existence, and making light of the situation. The few people he gets close to, generally seem to be confused by his behaviour.

Having watched the first 4 episodes, I've noticed something rather peculiar: No one ever acknowledges Mr. Robot, except Elliot. Is there any evidence that Mr. Robot is or isn't just in Elliot's head, similar to      Fight Club?


Is there a way to add text before the hyperlink?  So for example:     This section needs reworking. You can find the section HERE.    HERE would be the text replacement for the actual link. The actual text would read like this.  This section needs reworking. You can find the section =HYPERLINK("www.yourlink.com", "HERE").   When I try this is does not work, so I am thinking if there is a way it might use some different code.

I've got a document that's convenient to keep in a spreadsheet because of calculations, but I also have a significant amount of text that I'd like to keep in the same place. Some of that text involves hyperlinks, preferably in line with plain text, but my attempts at figuring out how to write a formula that prints the output from HYPERLINK() next to plain text have all resulted in parsing errors.  The result I'm looking for is      plain text   So far I've tried  =HYPERLINK("http://google.com", "Google") + plain text =CONCATENATE(HYPERLINK("http://google.com", "Google"), plain text)   Google's documentation isn't leading me anywhere.


I'm playing minecraft 1.7.2 and I type /gamerule keepinventory true, and it says that there's no keepinventory rule. How do I keep inventory on death? I'm fighting the Ender Dragon and keep dying.

I once played a vanilla Minecraft adventure map (called "Herobrine's Mansion") that prevented the player from losing their items on death. Which commands can be used to prevent the player from losing their items on death (in vanilla Minecraft)?


this is my 1st question in stackoverflow.  var str="Oct 13,2011"; var date1=new Date(str); var date2=new Date(str);   of course valueOf(date1)==valueOf(date2)  but why date1!=date2  or say,how to determine 2 date object if they equal each other.  Date is a js object

Can someone suggest a way to compare the values of two dates greater than, less than, and not in the past using JavaScript? The values will be coming from text boxes.


Maybe 3 years ago I have bought my laptop where I had default OS Windows 10. I also wanted to have Ubuntu OS as dual-boot with Windows 10. But I had no experience with installation OS so I have installed Ubuntu in different boot mode. Now I have Windows 10 which is installed in UEFI boot mode and Ubuntu 20.04 which is installed in Legacy boot mode. Both OS are installed in the same SSD (I have only one external disk). Is there some way how I could change boot mode on Ubuntu to UEFI where I could then using GRUB choose which OS I will boot without regular switching from one boot mode to another ? I would like to do that without reinstalling the whole OS. Thanks.

Accidental BIOS mode install  I have Intel 64-bit hardware with UEFI setup utility. Ubuntu 14.04.1 LTS was  installed as the only operating system on the only drive attached. Accidentally Ubuntu was installed in BIOS/CSM/legacy mode.  Convert to UEFI  While later on learning about UEFI, the goal is to change this existing Ubuntu installation to (quicker) boot via EFI/UEFI. I do still want to have some kind of - 2 seconds displayed - boot menu that allows me to enter the UEFI setup utility. Therefore I think I do need use Grub (can't use an EFI boot stub) and . I have already re-partitioned the drive using a Live CD and inserted a 200 MiB EFI partition in the beginning of the drive and marked that fat16 formatted partition as type id 0xEF.  Before:  # fdisk -l /dev/sda ...    Device Boot      Start         End      Blocks   Id  System /dev/sda1   *        2048   108478463    54238208   83  Linux /dev/sda2       108480510   125044735     8282113    5  Extended /dev/sda5       108480512   125044735     8282112   82  Linux swap / Solaris   After:     Device Boot      Start         End      Blocks   Id  System /dev/sda1   *      411648   108478463    54033408   83  Linux /dev/sda2       108480510   125044735     8282113    5  Extended /dev/sda3            2048      411647      204800   ef  EFI (FAT-12/16/32) /dev/sda5       108480512   125044735     8282112   82  Linux swap / Solaris  Partition table entries are not in disk order   No boot-repair please  The Ubuntu community wiki suggests to use boot-repair to . I don't want to use a GUI, or install any extra packages, and I don't want any data being accidentally sent to pastebin.com and because I do want to know what will be changed exactly, I don't want to use .  Under the hood  Trying to figure out what boot-repair actually does, I found this snippet:     Boot-Repair will convert a BIOS install to UEFI by uninstalling grub-pc, and installing grub-efi, if gpt partitioned.   source:   UEFI mode install comparison  A clean Ubuntu 14.04.1 installation in UEFI mode creates a 512 MiB Fat32 formatted EFI partition. That partition contains one directory /EFI/ubuntu, containing 4 files: grub.cfg, grubx64.efi, MokManager.efi and shimx64.efi. The grub.cfg contains:  search.fs_uuid 7d843e47-3917-4114-8725-55dfa1fbe002 root hd0,gpt2 set prefix=($root)'/boot/grub' configfile $prefix/grub.cfg   Search.fs_uuid points to the UUID of the Linux installation partition, in this comparison UEFI installation Linux is installed partition /dev/sda2 (versus sda1 in BIOS mode installation).   No potential Asrock firmware issues found  Having CSM still disabled in firmware and using the clean UEFI mode Ubuntu installation. Resizing the 512 MiB EFI partition to 200 MiB using a Live CD and gparted results in that its formatting changes from FAT32 to FAT16. The Asrock firmware P1.50 (incorrectly called BIOS by AMI in boot message "BIOS date") is still able to boot into UEFI mode Ubuntu: UEFI+FAT16 = ok. (msdos) using the same Live CD terminal command gdisk and its commands r g p w also results in a UEFI bootable Ubuntu on an MBR partitioned drive: UEFI+MBR = ok.   Question  Does this mean that the only commands I do need to execute - from the legacy Ubuntu install and in this order - are:  # apt-get install grub-efi # apt-get remove grub-pc   ? Or is more needed to be done?


I have the following sentence:     "Statistics is my passion and I am always eager to accept new   challenges"   I am not sure about the statistics and the is.  Is this correct? Because statistics is plural and so do I have to use are? Or should I use just      statistic is my passion   in this context, so singular version of statistics?

Why is the sentence "Statistics is often misleading" incorrect?  I know that statistics can be singular but also plural. Should I use singular in this case?


Related to the question: .   I was wondering if there is a minimum length for Minecraft usernames?

What is the format of  account names?  The information I have a use for is:   what characters are permitted or prohibited? what is the maximum length? are they always treated as case-insensitive?   However, a complete, exact definition of the allowed format would be appreciated.


I am travelling from Paris to Cologne with a one-day stopover in Brussels.  Where can I store luggage at the Bruxelles-Midi station?

Is there a place where one can leave luggage for more than one day in Brussels? It can be either in the airport or the central station.  I know that there are lockers in the central station. The problem is that these are usually restricted to 24h.  Are there any other services, in Brussels, that take luggage for longer than 24h?


On the regular site, there's an [On Hold] indicator after the title when a question has been closed. It would be nice to have something similar for the iPhone app. It's a bit frustrating to waste time clicking on a question only to realize that it's off topic after it loads.

Testing the app, I noticed the title does not specify if a question is "On Hold" ... I haven't checked specifically, but would assume it doesn't specify as "Duplicate" either ... Or am I missing it somewhere? Is it not in the title but located/displayed some other way? If it is, this could be very confusing to users. If it isn't there, it's definitely confusing to users :-)  Using: Version 1.0.1.125 on iPad3 with iOS8


you can find details about the software and hardware on which the site is built.   I am wondering do developers write any automation tests (unit/functional/scenario) and what kind of tools/libraries are using?  More specifically, how they are testing their T-SQL objects (functions, procedures, schemas).

Stack Exchange is my role-model for application development.  I've tried to learn as much as possible from the blog and podcasts, from thought process to design, architecture, convention, etc etc.  I'm just about to wrap my head around TDD and am curious about how the SE team approaches it.  Is there a methodology that all team members follow, or is it more developer-driven testing where you pick complex bits to unit test as needed, or is it more about catch-all integration testing once a piece of functionality is done, or... ?  Any input would be fantastic.


Whenever I boot to Ubuntu 13.10, it goes to a black screen with my cursor that looks like an a X. There is also a System program problem detected message box in my used theme, and I can switch to console logins fine. I have already tried booting with nomodegui or whatever that is, and it doesn't solve the problem.

I am trying to boot Ubuntu on my computer.  When I boot Ubuntu, it boots to a black screen.  How can I fix this? Table of Contents:


As I learnt freq. observed by a observer from a moving source is given by $$f=f_0(1+v_s/v)^{-1}$$ If $$v_s=-v$$ f is infinity.Whats going on? Will Doppler effect will be observed if the source say is a fighter plane moving at mach 1 towards observer? My intuition is that Doppler effect is not observed am I correct?

Say an airplane flies at Mach 1. The doppler effect causes the front of the sound emitted by the plane to reach infinite frequency:    $f = \left ( \frac {343+0}{343-343} \right ) f_0 = ∞$  If the plane suddenly stopped, and there was an observer in front of the sound waves to receive the sound, what would the bunched up waves sound like to the observer? Would they cancel each other out and cause no sound?


I have been working on this all day and can't figure out why I can't pull this to print of the main class, keeps throwing an error     An unhandled exception of type 'System.StackOverflowException' occurred   I've tried a few things now and nothing. It works to pull my list from on another class, but I can replicate it. Sorry about code been adjusting a lot  using System; using System.Collections.Generic;  namespace MpaintV2.Customer {     public class Trade     {         public String TradeName { get; set; }         public String TradeAddress { get; set; }         public String TradePhone { get; set; }         public Double PaintCoverage { get; set; }         public String TradeNames { get; set; }          public string RecCal         {             get { return RecCal; }             set { RecCal = RecCal; }         }          public string DataTrade         {             get             {                 List<string> FileData = Utilities.Helper.get_file_data();                  for (int counter = 0; counter < FileData.Count; counter++)                 {                        String[] SplitRecord = FileData[counter].Split(',');                      if (SplitRecord[0].Equals("Trade"))                     {                         TradeName = SplitRecord[1];                         TradeAddress = SplitRecord[2];                         TradePhone = SplitRecord[3];                         PaintCoverage = (double.Parse(SplitRecord[4]) / 10.00);                         // Console.WriteLine(" " + TradeName + " " + TradeAddress + " " + TradePhone + " " + PaintCoverage + "Paints");                         //List<String> TradeFiles = new List<string>();                         //TradeNames = String.Join(TradeName, TradeFiles[500]);                     }                 }                  //TradeFiles = TradeName.Insert.TradeFiles;                 RecCal = TradeNames + TradeAddress + TradePhone + PaintCoverage + "otherthings";                 return RecCal;             }         }          public override string ToString()         {             return base.ToString();         }     } }

I know java and would normally put in getter/setter methods. I am interested in doing it in C# with the following code, but it throws a StackOverflow exception. What am I doing wrong?  Calling Code  c.firstName = "a";   Property Code    public String firstName; {     get     {         return firstName;     }     set     {         firstName = value;     } }


Was it decided empirically (in order to respect the already found Conservation of Energy's law) that force x displacement is the quantity that corresponds to the energy ?  It's a deeper question than it looks, at least for me :)

is defined as the dot product of force and displacement.   However, intuitively, should it not be the product of force and the time for which the body is acted upon by the force (force * time) because while time is independent of force applied, displacement is not.  Were these formulae (for work and energy) actually derived based on some physical understanding or are they just constructs to understand forces better?


I want to install phpmyadmin from the repository, but I don't want to change my current php versione. The default apt command would install php8... but php8 it is to early for me. How can I install phpmyadmin with APT without dependencies?

Being an early adopter and using 11.04 daily builds I sometimes meet a situation when some packages require earlier versions of other packages than those I have installed. Usually newer (but refused) versions of needed packages provide all the functionality of their older versions.  If I use dpkg -i --force-depends-version to install dependent packages everything works fine, I've never seen a problem.  Instead of manually downloading and installing every package, can I just make the system pretend there is a specific package version installed when there is a newer? Or is there a --force-depends-version key equivalent for apt-get?


I'm trying to build a restful controller with HAL links and custom methods. When I'm using a getResources from PersistentEntityResourceAssembler (HAL links) and this cause NullPointer.    StackTrace  java.lang.NullPointerException: null     at pl.com.tt.sok.core.component.attendance.entity.PersonAttendanceListBuilder.addAttendance(PersonAttendanceListBuilder.java:37)     at pl.com.tt.sok.core.component.attendance.service.AttendanceStatusService.createAttendanceListForPersonBasedOnRequestedDates(AttendanceStatusService.java:50)     at pl.com.tt.sok.core.controller.attendance.AttendanceStatusController.getPersonAttendanceList(AttendanceStatusController.java:34)     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)     at java.lang.reflect.Method.invoke(Method.java:497) ...   PersonAttendanceListBuilder  @Autowired private PersistentEntityResourceAssembler assembler; (...)  private PersistentEntityResourceAssembler assembler;     public PersonAttendanceListBuilder addAttendance(Attendance attendance) {     PersistentEntityResource resource = assembler.toResource(attendance); //(37)     this.attendanceList.add(resource);     return this; }   AttendanceStatusService              attendance = attendanceRepository.findByDateAndPerson(Date.valueOf(day), person);         if(attendance==null){             attendance = new Attendance();        }         listBuilder.addAttendance(attendance); //(50)

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?


Currently I've faced this issue. on Hinduism.SE I see 1 suggested pending approval:    But clicking on which the page says:     This queue has been cleared! If you're looking for more to review, view all review queues.    Also review page says 0 suggested edits:    Note that this is not issue that before I clicked on 1, there was one suggested edit pending and when I clicked, it is already reviewed. Because I've reloaded page many times, even after 10 minutes I'm still getting 1 notification on top bar in spite of there is not any pending suggested edit approval.

What is the actual source of the number displayed next to the review link in the top bar? I found  (via  and similar) but, and apologies if I'm being dense, the answer there didn't seem to have an explanation of where the specific number comes from.  I can't make any combination of task counts on /review (that are visible to me, at least) add up to the number in the top bar. I had thought that perhaps it was a count that just lagged a little behind the /review counts, but it changes often and quickly enough (and is so far off from the other numbers that I see on /review) that I can't imagine how this could be the case. Perhaps there are items or queues that I do not have the privileges to see, but I don't know what those are, and finding out what they are (if that's the case) is part of this question. I've also been told in chat that it is actually the


The given limit is:   $$\lim_{x \to \infty} \left (\cos \dfrac {1}{x} \right)^{\displaystyle x^2} $$      The answer is $\dfrac{1}{\sqrt e}.$      My working: $$\lim_{x \to \infty} \left (\cos \dfrac {1}{x} \right)^{\displaystyle x^2} $$ $$=\lim_{x \to \infty} e^{\displaystyle \ln{\left(\cos \dfrac {1}{x} \right)^{\displaystyle x^2}}} $$ $$=\lim_{x \to \infty} e^{\displaystyle \ln{\left( \sqrt {1-\sin^2 \dfrac {1}{x}} \right)^{\displaystyle x^2}}} $$ $$=\lim_{x \to \infty} e^{\displaystyle \ln{\left({1-\sin^2 \dfrac {1}{x}} \right)^{\dfrac {x^2}{2}}}} $$  I am stuck at the 4th limit and I don't know how to go on. What should I do?

I've been trying to solve this limit: $$\lim_{n\to \infty} \left(\cos\left(\frac{1}{n}\right)\right)^{n^2}$$ I solved it using l'hopital but I have to try in another way. I tried to make the expression:  $$ \lim_{n \to \infty}\exp\left(n^2\ln\left(\cos\left(\frac{1}{n}\right)\right)\right)$$  but it didn't work out for me...


I have an older Rails 3 app that use SQLite3 database. I need to switch it to MySQL - that's kind of easy-peasy.  The problem is that in the SQLite3 database is a scheme of categories - about 500. I need to export these categories from SQLite3 database and import them into the newly create MySQL one.  Now the thing is (as I haven't done it before) - how to make this kind of migration in its simplest way?

Anyone know a quick easy way to migrate a SQLite3 database to MySQL?


I have a problem with my WordPress website being too slow, I installed a debug bar to check queries in the home page, it reports 202 queries, and a total query time equal to 1665ms.  The cpu and the ram are in critical use.  Here is what i tried to do:  Optimize pluginDB to defrag the DB. ThemeCheck plugin to analyse and clean my template. W3C Total cache Plugin with object cachr enabled.  Necessary plugins are:  WordPress SEO by YOAST Jetpack service by WordPress.com Contact form 7  Thank you

Are there any ways in which I can improve the loading speed of a website?  I know that Google is really pushing loading speeds and with the popularity of mobile websites it's now imperative that sites load quickly.


I would like to know whether any of these sentences are correct:     Yesterday, I found out that all the money I had in my bank account   has been stolen from me.      Yesterday, I found out that all the money I had in my bank account   had been stolen from me.   Or should I just use "was" in this case? Thanks!

I have never had this problem before. But after seeing some questions posted on ELU, I started to doubt. I have been through links1, pages of grammar books2, a lot of questions3 posted here and ELU. I now still can't seem to understand how the past perfect is exactly used. The references sometimes even contradict each other.  What I had understood so far was      The past perfect is not necessary if we are not 'going back' to the earlier past, and simply moving from one event to another.   but I then saw a lot of other 'rules' including      If the sequence is clear, the past perfect is not needed.   which is slightly different, less 'narrow' and can be applied in more situations than the first ruleA, and      The past perfect is optional only when talking about an action at a specific time.   This is confusing. Can anyone here clarify things out please?    A For example, for  Doing the survey [completed] -> Showing the result      We showed the result of the survey we did.      If the second rule is applied, the sentence above is fine (the sequence is clear), but not if the first rule since we are not moving from any event to the next and possibly even going back.    1  and   2 Practical English Usage (2005) by Michael Swan, Collins Cobuild Student's Grammar (1991). Upper-Intermediate Cutting Edge.  3 including , , ,  etc.


I understand that you should use an if the following word begins with an h, however if there is some punctuation (such as a fullstop) in the next word, should it still be an?     Do you have an .htaccess file?   or     Do you have a .htaccess file?

99% of the time, I'm clear on when I should use "a" versus "an." There's one case, though, where people & references I respect disagree.  Which of the following would you precede with "a" or "an," and why?   FAQ FUBAR SCUBA   [Note: I've read the questions  and , but the rules given there don't necessarily apply here.]    [Edited to add]  Here's a shorter (and hopefully clearer) version of the question…  In written English, which is correct (and why): "a FAQ" or "an FAQ"?  Some references with differing opinions:   an: the  and  a: the Microsoft Manual of Style for Tech Publications, 3e either: the  and


I am using grep console plugin in my development environment and I want to highlight parts of my console that look like '&name='.  I tried with following regex: [&].*[=]  I want lines like this:     lorem&variable=something{ipsum}&paramter="555"   to look like this     lorem&variable=something{ipsum}&paramter="555"   What would be the grep command to do that

I have this gigantic ugly string: J0000000: Transaction A0001401 started on 8/22/2008 9:49:29 AM J0000010: Project name: E:\foo.pf J0000011: Job name: MBiek Direct Mail Test J0000020: Document 1 - Completed successfully  I'm trying to extract pieces from it using regex. In this case, I want to grab everything after Project Name up to the part where it says J0000011: (the 11 is going to be a different number every time). Here's the regex I've been playing with: Project name:\s+(.*)\s+J[0-9]{7}:  The problem is that it doesn't stop until it hits the J0000020: at the end. How do I make the regex stop at the first occurrence of J[0-9]{7}?


For example, here's my command I'm using:  tr -d '\n' < newfile.ppm    I want to output the results to that exact same file, so I am now doing:  tr -d '\n' < newfile.ppm > newfile.ppm   Why is this not working and how can I get it to work?

Possible Duplicate:          I frequently connect to amazon ec2 using their public DNS names (ec2-12-34-56-78.compute-1.amazonaws.com) and because of this my known_hosts file gets overwhelmed with a lot of ec2 entries I will never use again.  I know I could probably use sed -i to edit in place but I wanted to use grep and so I did this:  grep -v ec2 ~/.ssh/known_hosts > ~/.ssh/known_hosts   That leaves known_hosts as an empty file. If I do:  grep -v ec2 ~/.ssh/known_hosts > ~/.ssh/tmp mv ~/.ssh/tmp ~/.ssh/known_hosts   then things are fine, but I am confused why reading and writing to the same file leaves it blank, and if there is any way around this when using grep, cat, etc.


I have a doubt about the lagrangian of the Schrodinger equation. If we consider the  wave function $\psi(\textbf{x},t)$ that satisfy the Schrodinger equation as a field, one way of construct the Lagrange Density $\mathcal{L}$ is try an ansatz  $$\mathcal{L} = i\hbar \psi^{*}\dot{\psi} - \frac{\hbar^{2}}{2m}(\nabla \psi^{*})\cdot (\nabla \psi) - V(\textbf{x},t)\psi^{*} \psi,$$  and show that this leads to the Schrodinger equation using the euler-Lagrange equation for $\mathcal{L}$:  $$\frac{\partial \mathcal{L}}{\partial \psi^{*}} - \partial_{\mu} \frac{\partial \mathcal{L}}{\partial(\partial_{\mu} \psi^{*})} = 0.$$  In the book "Field Quantization" of Greiner, it's said that we can consider the field  $\psi(\textbf{x},t)$ and its complex conjugated $\psi^{*}(\textbf{x},t)$ as independents fields, so the Lagrange Density will be a function of $\psi$ and $\psi^{*}$ and their partial derivatives. What's the reason for this? The book dosen't give explanations.

I am new to QFT, so I may have some of the terminology incorrect.  Many QFT books provide an example of deriving equations of motion for various free theories. One example is for a complex scalar field: $$\mathcal{L}_\text{compl scaclar}=(\partial_\mu\phi^*)(\partial^\mu\phi)-m^2\phi^*\phi.$$ The usual "trick" to obtaining the equations of motion is to treat $\phi$ and $\phi^*$ as separate fields. Even after this trick, authors choose to treat them as separate fields in their terminology. This is done sometimes before imposing second quantization on the commutation relations, so that $\phi$ is not (yet) a field of operators. (In particular, I am following the formulation of QFT )  What is the motivation for this method of treating the two fields as separate? I intuitively want to treat $\phi^*$ as simply the complex conjugate of $\phi,$ not as a separate field, and work exclusively with $\phi$.  Is it simply a shortcut to obtaining the equations of motion $$(\square +m^2)\phi=0\\ (\square + m^2)\phi^*=0~?$$  I also understand that one could write $\phi=\phi_1+i\phi_2$ where the two subscripted fields are real, ; perhaps this addresses my question in a way that I don't understand.


Assuming I have a model like this (I shortened it a bit):  class NewsletterDatum {     public string FullName{ get; set; }     public string Email { get; set; }     public string OptOutLink { get; set; }     public long ConciergeId { get; set; }     public long AwardCount { get; set; }     public int YearsMember {get; set; }     public string CardNumber { get; set; }     public string MemberName { get; set; }     public string PointBalance { get; set; }     public List<string> StoredKeyWords { get; set; }     public List<string> FriendIds { get; set; } }   I want to get the list of properties of this model that are not numerical, is there a way of doing this without comparing types with int, long, decimal, etc..?

But here's an example:  Dim desiredType as Type if IsNumeric(desiredType) then ...   EDIT: I only know the Type, not the Value as a string.  Ok, so unfortunately I have to cycle through the TypeCode.  But this is a nice way to do it:   if ((desiredType.IsArray))       return 0;   switch (Type.GetTypeCode(desiredType))  {       case 3:       case 6:       case 7:       case 9:       case 11:       case 13:       case 14:       case 15:           return 1;  }  ;return 0;


Disc Management SC - can't find my external HDD:    My Computer SC -  can't access my external HDD:    Attached above are the screenshots showing how i can't access the files i have on my external HDD. It was still working perfectly fine yesterday but i was unable to access it today. What should i do to atleast fix the external HDD or recover the file?   Thanks

What steps can I take to try to recover lost or inaccessible data from any storage device?  Answers:   This applies to any computer storage device, e.g. internal/external hard drives, USB sticks, flash memory. The most important thing is to STOP using it, any type of I/O can ruin your chances of a recovery.     We have separate questions covering common problems with USB flash drives in greater detail:


I am writing a chapter of my thesis in Latex, the page numbers are on top left corner which are adjusted with the chapter heading as shown in the picture :     While 2 is the page number and I need a space between 2 and Chapter 1. My code is just  \documentclass[b5paper,11pt, titlepage]{book}  \chapter{Guided Wave Based Structural Health Monitoring} \textbf{My name} \tableofcontents \newpage   when I give the chapter name shorter it works fine but when I write the complete name/title of the chapter, it makes this problem.  I am new to Latex, please help me with this problem. Thanks.

How can I format the header on every page displaying the title of the current chapter? In one of my chapters the title is too long so it is running out of the page.  Here's a minimal example of my document:  \documentclass[bibliography=totoc,version=first,listof=totoc,BCOR5mm,DIV12,index=totoc,numbers=noenddot]{scrbook} \usepackage{bibgerm} \usepackage[english,german]{babel} \usepackage[utf8]{inputenc} \usepackage{a4wide} \usepackage{wrapfig} \usepackage{caption}  \begin{document} \frontmatter \mainmatter \chapter{Very long title} \backmatter \end{document}   Here's a screenshot of my problem:


If you played clash royale while released for Canada only(I think) There was no spell in arena 1 so now I'm at arena 2  And I played in the beta Does this mean I can't get a lighting spell or do I just have pray for one in a chest?

I've advanced to Arena 2, but I don't see an option to go back to previous arenas in order to continue collecting the previous chests. How can I go back to previous arenas? If it's not possible, how can I collect the cards from the previous arenas?


I have created a button. In the event handler for the button I want to delete all the files in the folder (abc).   Here is the code for this:      private void button1_Click_1(object sender, EventArgs e)     {         MessageBox.Show("Are you sure!!!! The files in the folder will be deleted permanently");         this.Close();         string[] filePaths = Directory.GetFiles(@"C:\abc\");         foreach (string filePath in filePaths)             File.Delete(filePath);     }   For example, there is a Word file in the folder and if it is opened I get a error message:     The process cannot access the file 'C:\abc\New Microsoft Word   Document.docx' because it is being used by another process.

I've seen several of answers about using  or , but I would like to be able to find out in my own code (C#) which process is locking a file. I have a nasty feeling that I'm going to have to spelunk around in the win32 API, but if anyone has already done this and can put me on the right track, I'd really appreciate the help. Update Links to similar questions


I managed to remap the Caps Lock key to Escape, but I can't find a way to remap the Escape key to Caps Lock.  The reason why I want to do this is that I usually use X11 on Linux where this is available as an option.

I generally run Linux. I use Vim a lot, so the Escape key is extremely important. I also use other keyboard shortcuts a lot, so Control is "key" as well. On Linux, I've solved this by using  to map the Caps lock key to Escape if pressed by itself, or Control if pressed in combination with another key. This puts the best of both worlds within quick reach of my pinky finger. Is there any way I can do this on a Mac?


I have made a chain of toruses, when I apply rigid body physics to it, it breaks as soon as I play animation. I have tried scaling it up but does not help. Please help me fix it.  Blender file is :  Chain is in 2nd layer.

I have made some chain links. I used the Rigid Body Tools and made the two end links passive and the others active. They are all set to shape Mesh. I've tried setting the weight to acrylic, cardboard, etc to lessen the pull they have when falling. How do I prevent these links from coming apart? I've even tried scaling up the scene but that also doesn't work.  Peter


I have a CentOS system that retrieves its upstream DNS servers via DHCP.  I want to run DNSMasq on this box and use it as a server to resolve some hostnames for development.  The problem is when my system starts, the upstream DNS servers are loaded into /etc/resolv.conf and THEN the DNS1 entry from my ifcfg-enp0s3 setup gets loaded.   That's a problem because when I query for the internal dev names, it tries to go out to the upstream DNS server instead of checking DNSMasq first.  I need the DNSMasq server to be at the TOP of the /etc/resolv.conf and the dhcp loaded ones at the bottom of the resolv.conf so that DNSMasq will work properly.  Any simple way to do that?

Right now, my /etc/resolv.conf looks like this:   # Generated by NetworkManager nameserver 10.165.246.33 nameserver 192.135.82.60 nameserver 10.165.74.2   The first two nameservers are automatically configured through DHCP; the last one is the one I added manually, in NetworkManager. It's also the most important one, since it resolves our internal domain names (e.g. build-server-17.our-company-domain.com).  The trouble is, NetworkManager adds it to the bottom of /etc/resolv.conf, so when accessing an intranet URL, my browser tries to resolve it using the first two servers, and it takes ages.  How do I make NetworkManager add the manually-configured DNS server before the automatically-configured ones?


I am trying an assignment problem  which I am unable to think about.      Question is -> How many $4$-subsets of $S= \{1,2, \ldots,20\}$ contain no consecutive integers?    I don't have any idea how to solve it.   Can someone please explain how to think about it ?

I am a newbie in combinatorics and still don't have enough tools to handle this kind of problems.  Assuming I have a set of integers: $ \{1,2,3,4,\dots,n\} $  In how many ways, can I choose $k$ numbers out of those $n$, such that none of them are consecutive?  For instance, for the following set $ \{1,2,3,4,5\} $  For $ k=3 $ I have only 1 option: $\{1,3,5\}$  My purpose is first of all to understand the way you would think about this  problem, not necessarily the solution itself (I have the final answer for it).  Thanks.


For this simple code snippet why is the floating point precision showing 0.30000000000000004 instead of 0.3 and how do I fix this?  prog.py  marker = 0 interval = 0.1  for i in range(10):          marker += interval     print(marker)   output  0.1 0.2 0.30000000000000004 0.4 0.5 0.6 0.7 0.7999999999999999 0.8999999999999999 0.9999999999999999

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


Every time I click on "Get this torrent", I get a window asking to choose a application:     I have qBittorrent installed but I don't know how do I select it from this windows which open when I click on "Choose" from the previous window.

I can't find out how to make Firefox open magnet-links in Transmission.   There is no option to make it the standard program for magnet-links in its properties, and as I am not experienced with the filesystem so I can't add it as the standard program in Firefox either.


I totally agree that the key feature of a high level academic forum is the audience choice, which is by all means given in terms of up and down votes. Nevertheless, I would like to point out some little misbehaviours thereof and suggest if, at least for some sections, downvotes could be removed at all.  I am a theoretical physicist and, although having always been a big fan of this platform, I have only joined it actively lately. The reason is that most of my colleagues and my community left the forum after a while due to the ridiculous way people downvote correct proofs in mathematics without even giving (possible) counterexamples. I regret I have to say this has been happening to me as well and is giving me good thoughts to drop the forum as they did, without wasting any more time if people do not even read the solutions.  If you  find the answer useful then one may upvote. If not, one can just not upvote it, leaving it to zero score. Downvoting an answer without counterproofs, besides questioning someone else's effort and time, also evens out and discards all the ones who had previously upvoted the same answer. Especially in technical areas (physics, mathematics, chemistry and so on) a proof is either true or false and I would suggest that in those sections downvotes, if still useful at all, should be allowed only after proving the related answer to be explicitly wrong, giving a counterexample or meaningfully expanding it. Otherwise, no downvote should be allowed.   I have seen that many other users pointed out, along similar lines, the same feeling. What's the state of the art about this issue here?

As far as I can tell downvoting is mostly useless.     For questions the only people who get downvoted are lower rep users, or incredibly stupid questions    most questions that are downvoted get closed anyway which should be sufficient downvoting doesn't have too much affect on your rep anyway a negative comment is more useful and more of a push too change or delete the question  For answers downvoting is often used incorrectly as well   people commonly competitively downvote (downvoting another answer to a question that you also answered) obviously not a good behavior downvoting (and upvoting) are contagious, meaning one downvote leads to a bunch of others even though downvotes don't effect rep that much they create a negative environment, no one wants their post downvoted, on the other hand criticizing comments, I think, are far more welcome      So basically in a nutshell a downvote serves no real purpose even if a post deserves it. Flagging, closing and commenting are much more useful to everyone including the poster than downvoting so why have it.    I now see from the answers and comments that downvotes do serve a purpose and would like to retract my request.


Novel from the late '80s - early '90s. Can't remember much about it - didn't finish it. About a humanoid (Alien? Time traveler? Can't remember) who visits Earth in the Middle Ages & gets involved with two people. One of them is a Norman knight who tries to take advantage of the traveler's advanced technology to defeat his enemies.

Book was late 70's early 80's science fiction/fantasy. What I can remember was the main characters (four) were a brother and sister (who were either Human or almost-human) with a pair of telepathic (and very intelligent) Panther-like copilots. Their spaceship crash lands on Earth in medieval times Europe. (sometime in the early 1000's) At least one of the kids (I think the girl, but not sure) gets separated from the others and is taken by the local lord. The lord quickly realizes the kid has smarts and uses him or her to help defeat his enemies. I know this isn't much to go on, but can't remember a lot else about the plot. I'm sure it was written by one of the major writers of the age (Andre Norton, Piers Anthony, et al), but haven't been able to locate it. The cover of the book I had showed the two panthers kind of surrounding the 'window' looking out to the kid or kids and a castle. Books it isn't: The Barque Cats, Pet Cemetery, Pride of Chanur, Timecat, Cats of Ulthar, any of the Honorverse (Go Nimitz!), Tail Chaser or Master Ren. Also, this was a singular novel, not part of an anthology or series. At least I don't think there was ever a sequel written.


I'm sort of a newbie here, so pardon me if I don't get any of the lingo right.   But I'm trying to create a level progression that charts with the "10,000 hr" rule such that, basically, each hour worked will equal 1 XP and level 99 (xx, if you will) charts with having accumulated 10,000 XP.   I understand how I can make a straight progression of levels, but what I really want to do is create a sloped progression, where you level up more often early and then it requires more and more effort to level up as the progress goes on. (The only targets, I guess, are level 1 being 0 and level 99 being 10,000.)  Any ideas? Can anyone help? (I'm sure this is simple, but if you can show me the way toward the answer, I'll gift you by first-born sword.)

Related questions under this topic might include:   How should I base how much experience points it takes to get to the next level? What factors are involved in this? How do I keep the player not entertained long enough till he levels up? How can I vary the way the player gets experience points?


Using  has no difference. I don't mind if it indents, but the image should be center-aligned.  \documentclass{article} \usepackage{graphicx} \graphicspath{{C:/Users/Ooker/Desktop/Images/}} \title{Quả cầu}  \begin{document} \maketitle text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text   \includegraphics[width=1\textwidth]{Octahedron}  test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test   I use XeLaTeX.

How do I align an image to centre?  In a beamer presentation I have a 2-3 items on a slide followed by an image. The image is not wide enough to cover whole slide, so it leaves around 30% space from right. How do I adjust it to leave enough space on both sides?  \begin{frame} \frametitle{Outlook} \begin{itemize} \item apps \item apps \item apps \includegraphics[scale=0.3]{P2P}     \end{itemize} \end{frame}


I would like to change the one photo you see for each album when you first open the Photos app.

I have an iPhone 6s with iOS 10.  In the Photos app, there are Albums and each Album has a cover photo.    How can I change the cover photo of an Album?


I am trying to run a big script that prompts for answers along the way. I want to run it in verbose mode and thus there will be significant output and I'd like to capture it.  Therefore I'd like to run it in a way that allows me to answer the questions as well as sending the output to a file.  Can this be done ?  Thanks.  Mike

I viewed  to redirect text to file while displaying the output. My question is how can I redirect it while working AND without constant | tee command.  My plan is to use  to identify terminal (Gnome or Guake) and record only Gnome for my Linux commands testing. So I need constant and immediate redirecting of commands and their outputs (with errors) to a file (say cmdlog.log).


My visa was refused for insufficient funds. There is no time to go through the whole visa application and it is expensive.   Would I be allowed to enter, or do I need to consult an attorney?   My airfare and accommodation have been paid, and I have $3000 as spending money. The airfare and accommodation are $2000 and $3000 is just spending money. This combined is $5000AU, or 3000 pounds; that is 200 pounds a day. Is this acceptable for travelling for 15 days in the UK from Australia?

The UK Visas and Immigration Directorate publishes  that provides helpful tips that can result in successful visa applications. Section 2 of this guidance opens is entitled "other documents you may want to provide" (emphasis mine).  Section 2: other documents you may want to provide – all visitors This section provides guidance on the types of documents that you may want to provide to help us consider your application against the Immigration Rules. Previous travel documents/passports, which show previous travel. Financial documents showing that you have sufficient funds available.  These must clearly show that you have access to the funds, such as:  bank statements building society book proof of earnings such as a letter from employer confirming employment details (start date of employment, salary, role, company contact details) where a third party (who is either in the UK or will be legally in the UK at the time of your visit) is providing financial support to you e.g. a business, a friend or a relative, documents to show that they have sufficient resources to support you in addition to themselves and any dependant family should be provided   The first item is "bank statements" and this ties in with the , which says...  evidence that you can support yourself during your trip, eg bank statements or payslips from the last 6 months  (Note 'eg' is a Latin abbreviation meaning "for example"; this appears to be optional rather than a fixed requirement.) Question: How should someone interpret this such that the chances of success are maximized? How many statements should I submit? What are they looking for and what do my bank statements tell about me?


I want to create an alias for grep like this:   grep argX ~/myfile   where argX is a parameter and myfile is always the same. How can I do this?

I want to know if I can pass an argument with an alias command.  for example:  alias d="dmesg|grep -iw usb|tail -5"    Now d will print the last 5 lines. If I want to use d to print a different number of lines, I have to make change in the alias command declaration of d again.  Is there any way I can modify the declaration of an alias so that I don't have to retype the declaration to change the number of lines. Like incorporating passing the number of lines as an argument while declaring alias for d? Or is there some other method to solve this?


AST folder has 5 shapefiles. This code tries to pass the 2100 coordinate system to these shapefiles. But it gives error 999999:  arcpy.env.workspace = r"C:\Users\user\Desktop\roads\AST"  for i in arcpy.ListFeatureClasses():      sr = arcpy.SpatialReference("EPSG:2100")      arcpy.DefineProjection_management(i, sr)   How to make it work?

I've got a project where I'm reading in geometry objects from text files to put them in ArcSDE. These geometry objects have an associated EPSG code, and I'm looking for a way to ensure they're in the right projection when I've finished with them.  Having taken a look at the factory codes that I'm interested in, (GCS GDA94; EPSG:4283, and VicGrid 94; EPSG:3111) for a project I'm working on it appears that the EPSG codes correspond directly to the ESRI factory codes for the spatial reference ( and ). This is great, as it means I don't have to worry about navigating to projection files to create  objects, for example in the code below:  import arcpy  # Create a spatial reference object using a factory code # sr = arcpy.SpatialReference() sr.factoryCode = int(epsg_code.lstrip("EPSG:")) sr.create()   Unfortunately I can't find any reference in the ESRI documentation to say whether this holds true all the time or not - I'm guess it does, but I'd rather know for sure. Does anyone know where I'd be able to find out?


I want to be able to select certain vertices, apply a texture, and then select the rest to apply another texture. How can I do this?

I wish to select areas of a mesh, but it would be much simpler to just select the ones I don't want selected (because they are easier to access), and then inverse the selection.  Is this possible?


Here's a question that I'm trying to solve:     Let $a$ be the number of group homomorphisms $\mathbb{Z} \to S_3$ ;   let $b$ be the number of such one-one group homomorphisms; let $c$ be   the number of such onto group homomorphisms. Find $(a,b,c)$.   I claim that $c=0$. Proof of my claim: Suppose there were some onto homomorphism $\varphi : \mathbb{Z} \to S_3$. Since $\mathbb{Z}$ is cyclic, then $\varphi (\mathbb{Z})= S_3$ would be cyclic and thus abelian which is a contradiction.  Also that $b=0$ for we cannot find any mapping $\varphi$ which is one-one.  Now, finding $a$ is a big trouble. Here's my idea how to find $a$: Lagrange's Theorem tells us that there can be every subgroup of $S_3$ is either of the orders: $1,2,3,6$. And we know that $\varphi (\mathbb{Z})$ is a subgroup of $S_3$ so I tried manually to find the mappings. The answer I get is $6$. I was wondering if there was some easier way to do instead of explicitly finding the homomorphisms.  Yet another question I want to ask: Is the number of onto homomorphism from $\mathbb{Z} \to \mathbb{Z}_n$ equals the number of generators $\mathbb{Z}_n$ has i.e $\phi (n)$? I don't seek the proof but I was wondering if it was true.

I recently had my second abstract algebra exam returned to me and I missed this particular question (unfortunately I left the problem blank, just a bad test day). I've been trying to figure out the problem though and could use some help.  a) Does there exist a surjective homomphism $\phi: \mathbb{Z} \rightarrow S_3$? Explain.  What I'm thinking: Let $\phi: \mathbb{Z} \rightarrow S_3$ be a homomorphism.$\mathbb{Z}$ is a cyclic group and thus $\phi(\mathbb{Z})$ is cyclic. However, $S_3$ is not cyclic. Thus $\phi(\mathbb{Z}) \neq S_3$ and $\phi$ cannot be surjective.  b) Assume that there exist homomorphisms $\phi: \mathbb{Z} \rightarrow S_3$ where Ker$(\phi) \neq \mathbb{Z}$. What are the possible kernels? Explain.  What I'm thinking: Since $1$ generates $\mathbb{Z}$, if $1\in$ Ker$(\phi)$, then $\mathbb{Z}=$Ker$(\phi)$. So could Ker$(\phi)$ = $n\mathbb{Z}$ for $n \in \mathbb{Z},  \; n\neq1$?  c)List at least two non-trivial homomorphisms $\phi: \mathbb{Z} \rightarrow S_3$ whose kernals are not $\mathbb{Z}$.  $\phi_1(n) = (1\; 2)^n$  $\phi_2(n) = (1\; 3)^n$  Any input is much appreciated!


UINT64_MAX  is defined in <cstdint>: . This is what I've always used. However, I see C++ provides this alternative as well: std::numeric_limits<uint64_t>::max()  (see: ), which is part of the many numeric limits options defined in the <limits> header: . The C++ version seems overly verbose to me and appears to have no benefits. I assume it's included simply to be thorough, since they were adding additional functionality via other numeric_limits<> created in C++, but wanted to cover everything, I imagine, while they were at it. Is there any benefit of using the C++-only version (std::numeric_limits<uint64_t>::max()) over the C or C++ version (UINT64_MAX)? I'd really prefer the UINT64_MAX version, but in general find a lot of pushback from hard-core C++ developers whenever they see me write something in C++ which also would be valid in C. :) Note: I haven't had pushback on this one yet, but I'd like some insight first to see if there is something I'm missing which truly makes one version better than the other.  Update: here's my own answer: I'm not too happy this question was closed literally in the very same second as I pressed the submit button to add my own answer, but here's my own answer to this question: As @Bob__ pointed out in the comments under the question, std::numeric_limits<uint64_t>::max() is really preferred when writing a C++ template where the uint64_t part needs to be replaced with the typename T. However, if not in a template, it seems to me UINT64_MAX would be preferred since it's short, straight-to-the-point, less verbose, and easier to read.

I've been programming in C++ for a few years, and I've used STL quite a bit and have created my own template classes a few times to see how it's done.  Now I'm trying to integrate templates deeper into my OO design, and a nagging thought keeps coming back to me: They're just a macros, really... You could implement (rather UGLY) auto_ptrs using #defines, if you really wanted to.  This way of thinking about templates helps me understand how my code will actually work, but I feel that I must be missing the point somehow. Macros are meant evil incarnate, yet "template metaprogramming" is all the rage.  So, what ARE the real distinctions? and how can templates avoid the dangers that #define leads you into, like   Inscrutable compiler errors in places where you don't expect them? Code bloat?  Difficulty in tracing code? Setting Debugger Breakpoints?


I am traveling JetBlue to go to Florida from Massachussets and I realized after receiving my confirmation code that instead of my name going first-middle-last it goes -first-last-middle ... will this be a problem? I already contacted them but they have not emailed me back. Everything is spelt correctly there is just a mismatch of my name. Should I worry about not being able to board? My flight is about a month away so I'm trying to deal with it now.

I use my middle name pretty much everywhere.  At work I used to book travel myself and would always book under my first and last name.  We recently hired an admin who booked travel using my middle and last name.  Jet blue refused to change the ticket (or perhaps wasn't able to?).  The only option was to cancel the flight and re-book it at the last minute price, of course.  The other option is to show up to the flight and risk TSA refusing to let me travel.  Any advice?


I am trying to build an amplifier using op amp 741. But I am failing to build it on breadboard. I am connecting the positive end of a 9 V battery to pin 7 and negative end to pin 4. As per my knowledge and instructions available all over the internet. Pin 3 is to be connected with the input. The voltage source that I want to amplify has two leads coming out of it positive and negative. If I connect positive lead of my input to pin 3, where should I connect the negative lead?? Similarly, while measuring the amplified output from pin 6 what should be the other point of reference. I am need of a circuit fix. I am attaching the pic of the amplifier connections here. Your help will be really appreciated.

Simple enough question. Why not use a  in a target circuit or anyone's target circuit? What are the reasons not to use it? What might be the reasons to still choose this part?


I have fitted a normal copula to my data in R using the copula package and generated pseudo observations in the unit square [0,1]^2. I am having trouble retrieving the simulated values: how can I get x and y from u1?  from my understanding of the process, assuming x and y are normally distributed (for the sake of simplicity), I should do the following  x <- qnorm(u1[,1],mean(mat[,1]),sd(mat[,2])) y <- qnorm(u1[,1],mean(mat[,1]),sd(mat[,2]))   and these x and y should be my simulated real observations right? For some reason they do not fit that well my data as you can see below (simulated data are in RED and skewed upwards, and actual data are in BLUE).    What I need to know is: is the process correct or am I missing something? Is the use of qnorm correct as it is above or should I've used it differently?  By trying to use qnorm with the default mean=0 and sd=1 the simulated x and y seem to fit better, which I find odd since I thought actual mean and sd of x and y should be used. Am I correct?    Here is my code (except for the last part which is above)  library(copula)  x <- read.table("x.txt") y <- read.table("y.txt")  mat <- matrix(nrow=100,ncol=2)  for(i in 1:100) {     mat[i,1] <- x[,1][i]     mat[i,2] <- y[,1][i] }  #Actual observations plot(mat[,1],mat[,2],main="Returns",xlab="x",ylab="y",col="blue")  #Copula fitting normal.cop <- normalCopula(dim=2) fit.cop<- fitCopula(normal.cop,pobs(mat),method="ml")  #Coefficients rho <- coef(fit.cop) print(rho)  #Simulate data u1 = rCopula(500,normalCopula(coef(fit.cop),dim=2)) points(u1[,1],u1[,2],col="red")   Here you can find the data for x and y should you need it to run the code.   x and y are returns from two stocks

I have managed to  fit different kinds of copulas to my data in R (mostly Archimedean copulas) using the copula package.  I have no problem simulating pseudo observations (u and v), my questions are:  1) how can I convert these simulated data into values of the random variables I am trying to model? From what I get from Sklar's theorem I should use the inverse of the cdf, is it correct?  2) Assuming I am right in 1), another problem is I do not know which is the right inverse cdf to use, as a first approximation I can assume x and y are normally distributed (which is not entirely true due to fat tails), can't I?  Here is my code:  library(copula)  x <- read.table("x.txt") y <- read.table("y.txt")  mat <- matrix(nrow=100,ncol=2)  for(i in 1:100) {     mat[i,1] <- x[,1][i]     mat[i,2] <- y[,1][i] }  #Actual observations plot(mat[,1],mat[,2],main="Returns",xlab="x",ylab="y",col="blue")  #Copula fitting normal.cop <- normalCopula(dim=2) fit.cop<- fitCopula(normal.cop,pobs(mat),method="ml")  #Coefficients rho <- coef(fit.cop) print(rho)  #Simulate data u1 = rCopula(500,normalCopula(coef(fit.cop),dim=2)) points(u1[,1],u1[,2],col="red")   EDIT: Here you can find the data for x and y should you need them to run the code.   x and y are returns from two stocks


I found around half a dozen posts from me, done back in 2012 ish, that are not tied into my current account. How can a link be established?  Reading them it's obvious they're written by me, and not another 'Tim', of which there were several over the years!

I accidentally posted a question without being logged in. Is there a way to associate that question with my account?   For more information, visit "" in the .   a.k.a. How can you link a registered account to a cookie-based account? a.k.a. How do I merge an unregistered account with a registered account a.k.a. Merging users a.k.a. How do I associate anonymous questions I’ve asked with my registered account? a.k.a. Is there a way to claim an unregistered user? (in case anyone searches with those terms)


before Gutenberg I could query for all galleries in my blog with this:  $the_query = new WP_Query( $args );  while ( $the_query->have_posts() ) :     $the_query->the_post();       echo get_post_gallery(); endwhile;   But this does not output Gutenberg galleries. How do I output Gutenberg block galleries?

I have a site where I created a page that takes the gallery images from a post and puts them into a slider.   I used the following code:  // gets the gallery info $gallery = get_post_gallery( $post->ID, false ); // makes an array of image ids $ids = explode ( ",", $gallery['ids'] );   Then I inserted the images using wp_get_attachment_image().   Unfortunately, with WP 5.0 and Gutenberg, get_post_gallery no longer works with newly added content. It seems that get_post_gallery used a shortcode that no longer works with Gutenberg.   I am still getting up to speed on Gutenberg and the block system. Until I understand that all better, I was wondering if anyone has any advice on how to get the image ids from a gallery in Gutenberg?


I have 3 of the aforementioned servers, and when I netinstall centos on them, the installer recognizes the raid configuration and the logical disks and installs fine.  Upon reboot after installation, the server reports that it is attempting to boot from drive C: and never gets past that.  I've used CentOS on dozens of servers before and never really had an issue, but most of those were custom ordered to be compatible with CentOS.  These were dropped in my lap and I was told to 'make it work'.  The servers are Generation 8, and the have the HP Dynamic Smart Array B320i RAID controller.  I haven't had any time to do research on the issue myself, I just wanted to drop SF a line to see if anyone else had noticed a similar issue.  The system has six physical SSDs split into three logical drives, slots 1 and 2 are a RAID 1 for the OS.  Slots 3-5 are a RAID 5 for data, and slot 6 is a single drive for logs.  I tried switching the controller to AHCI which I read on some HP Knowledgebase, but that didn't seem to have an effect.  Any help is greatly appreciated.

I'm installing Ubuntu onto a HP Proliant DL360 G7 server, which has a hardware Smart Array RAID controller that is not compatible with Ubuntu.  HP say the RAID controller needs to be disabled in the BIOS in order to install Ubuntu.  The problem is, with the RAID controller enabled the installation can see the hard drives to install on but then can't boot, with it disabled the installation can't see any hard drives.  UPDATE: Ubuntu installs with hardware RAID active but hangs on "Attempting to boot from hard drive C:"  I've been advised to put the server into rescue mode and reinstall GRUB but holding down shift at any time during boot doesn't bring up the GRUB menu (I've tried it many times at different points), the Ubuntu Live USB does not have a rescue mode option.


I am trying to gain root user access to another user so that I can run a command with adding sudo in front of any command.  Example: fdisk -l  Getting the error message as:  fdisk: cannot open /dev/loop0: Permission denied fdisk: cannot open /dev/loop1: Permission denied fdisk: cannot open /dev/loop2: Permission denied fdisk: cannot open /dev/loop3: Permission denied   I tried to give the root user access to the user with the name sudhir.  switched to root user with su -  visudoers   Added the user as   root    ALL=(ALL:ALL) ALL sudhir  ALL=(ALL:ALL) ALL     Saved with ctrl+o, switched to user & executed the command fdisk -l, still getting the same error.  Any idea?

I have dual booted to lubuntu (with Windows XP) and everytime and then I'm getting asked for my password. How do I run everything as root and not ask a password again? Ideally I wanted to run nginx but it has permission denied issues:  apathetic@ubuntu:~$ service nginx start Starting nginx: nginx: [alert] could not open error log file: open() "/var/log/nginx/error.log" failed (13: Permission denied) 2012/08/03 20:06:25 [warn] 4762#0: the "user" directive makes sense only if the master process runs with super-user privileges, ignored in /etc/nginx/nginx.conf:1 nginx: the configuration file /etc/nginx/nginx.conf syntax is ok 2012/08/03 20:06:25 [emerg] 4762#0: open() "/var/run/nginx.pid" failed (13: Permission denied) nginx: configuration file /etc/nginx/nginx.conf test failed