A thorough explanation on why division by zero is undefined?

A Quick Note  I know there is a slough of related questions on stack exchange, but none of them really seem to answer my question. This  is the closest in relationship to my question, but the answer simply expresses a high level mathematical explanation, and not an example I can teach my kids. Growing up, my school always taught that division by zero was undefined or not allowed, but never really explained why, or how this was true.  The  has a very good answer, that I understand, however I'm not so sure my kids would understand that answer. The accepted answer will have to be understood by children under age 10 with a minimal working knowledge of multiplication and division.    Getting Started  The other day, I was working on a project at home in which I performed division by zero with a double precision floating point number in my code. This isn't always undefined in the computer world and can sometimes result in $\infty$. The reason for this is clearly explained in  and quite thoroughly in :     Division by zero (an operation on finite operands gives an exact infinite result, e.g., $\frac{1}{0}$ or $\log{0}$) (returns ±$\infty$ by default).   Now, this got me thinking about basic arithmetic and how to prove each operation, and I created a mental inconsistency between multiplication and division.    Multiplication  As this is an important part of the thought process that lead me down this mental rabbit hole, I am including the elementary explanation of multiplication.   If I place $10$ marbles on my desk, $3$ times, I have placed $30$ marbles on my desk.   This is expressed as $10 \cdot 3 = 30$ and is true.  If I place $10$ marbles on my desk, $0$ times, I have placed $0$ marbles on my desk.   This is expressed as $10 \cdot 0 = 0$ and is true.    These two scenarios are true no matter what numbers are used.    Division  This is where things took an unexpected turn in my mind.  Let's say that I am a wandering saint and I have 50 apples. I want to help the hungry people of the world so I give my apples away freely. Now, let's handle two similar scenarios.   I come across $10$ people, and I want to give them all of my apples, I also want to ensure that each person receives the same number of apples. With $50$ apples to disperse across $10$ people, this means each person receives $5$ apples.   This is expressed as $\frac{50}{10} = 5$ and is true.    However, let's say I have the same $50$ apples, and I come across a town where no one is hungry, and no one wants my apples. Well, I have $50$ apples, and I have $0$ people to give them to, so I still have $50$ apples. I didn't disperse my apples evenly across any number of people, so it's still the same bag of $50$ apples.  I believe this may be my mind's way of bending the facts here, and that I've convinced myself that I'm dividing $50$ zero times, but in fact I may have divided $50$ one time (by me). But it has me thinking, if I divide a pizza into zero equal slices, well then I essentially didn't slice the pizza and thus still just have an entire pizza.    My Question  How can it be proved thoroughly, not just with math, but with an example explanation (understandable by children) that division by zero is truly undefined?


From time to time I have some trouble using biber as a backend for biblatex. I did some reading and found out that I have to clear the cache from time to time... I am a beginner at this. How can I do it?


I am unable to open gnome-control-center due to an error stemming from pop repositories. Ubuntu 20.04

I am having trouble opening gnome-control-center. I have uninstalled and reinstalled which has temporarily alleviated the issue. Opening gnome-control-center through the terminal outputs this error: (gnome-control-center:7173):GLib-GIO-ERROR **: 10:55:20.351: Settings schema 'org.gnome.shell.extensions.pop-shell' is not installed. Trace/break point trap.  lsb release -a output: No LSB modules are available. Distributor ID: Ubuntu Description:    Ubuntu 20.04.1 LTS Release:    20.04 Codename:   focal  sudo ppa-purge ppa:system76/pop output: Updating packages lists PPA to be removed: system76 pop Warning:  Could not find package list for PPA: system76 pop  I did have the pop repositories installed, although I removed them before reinstalling gnome-control-center.


I have seen a few tips regarding the placement of periods before or after the closing parenthesis, but none of them solves my issue. A general rule of thumb-if the words inside the parentheses form a complete sentence, then period before closing it, otherwise period after closing it. However I am writing a sentence in the introduction part of a paper and the following options seem to be there   <,> denote the generalised inner product (see Section IV). <,> denote the generalised inner product (see Section IV.) <,> denote the generalised inner product (see Section IV.).   Which one among them is correct? A double period seems superfluous while placing it either inside or outside seem not to do justice to the whole sentence. Are there different conventions for British, American or Australian systems?


If $f(tx,ty)=t^n f(x,y)$, For all $t$, and $n$ is an integer $\ge 1$, prove this result

Let $f(x,y)$ such that  $$f(tx,ty)=t^n f(x,y)$$ for all $t$, where $n \in \mathbb Z^+$ Prove that $$x\frac{\partial f}{\partial x}+y\frac{\partial f}{\partial y}=nf(x,y)$$ This is my attempt First i want to get a formula for $\partial f/ \partial x$ $$f(x,y)=\frac{f(tx,ty)}{t^n} \implies \frac{1}{t^n}\cdot ?$$ but what is the partial derivative of $f(tx,ty)$ with respect to $x$?


Delete HTML elements with JS. WORKING JSFIDDLE

I made code to generate html rows.  How do I delete them now?? THis doesn't work   $('.deleteEnv').click(function () {    $(this).parents().remove(); });     $('#addEnv').click(function() {   $('#envVariablesDiv').append('

Name<input id="envName" class="form-control" name="envName" type="text" placeholder="e.g. name1" />

' +     '

Variable<input class="form-control" id="envVar" type="text" name="envVar" placeholder="e.g. var1" />

<button type="button" class="btn btn-danger deleteEnv">Delete</button>
'); });   <button id="addEnv">Add</button>


What point is there in using an everyday non-admin account on OS X?

This piece of advice is old but is coming back into fashion. I have seen it a lot recently, on a number of Mac websites or forums. "Your ‘everyday’ user account should not be an admin account. It should be a standard account created for this purpose, and you should log to the admin account only to perform actual admin tasks. »  This seems to be common advice in the Windows world, but for an up-to-date OS X system, I just cannot understand what kind of benefits it brings. Let’s dig into it:   OS X admin accounts are not root accounts. Any app wanting to go root will ask for your password anyway, so I see no additional security layer here. Try to put /var into the Trash. Deep OS modification or code injection into most critical files has been prevented by SIP from El Capitan, whether your are admin, root or nobody. What’s more, in sensitive places where they are still allowed, such modifications would require a root password at the very least, even from an admin account, bringing us back to the first argument. For spyware, privacy concerns and this kind of stuff, using standard accounts provides little additional protection, if any. As far as I know, even when used from a standard account, apps have full access to the user’s personal files and have full network access (minus any firewall, etc.). If a bad app wants to send home your docs, it can perfectly do so from a standard account. Basic lines of defense (firewall, running trusted apps, and so on) are system wide. On the other hand, it is a pain to switch to your admin account, then switch back to your standard account, back and forth. This may actually end up with the user delaying updates or admin maintenance, just to save time and postpone dealing with the hassle.   So, why not use an admin account? I hope this won’t be marked as duplicate, other questions related to this issue didn't address these arguments.  Edit: the question applies to a computer that you own and control.


Story about fantasy creatures as computers

I'm trying to recall a story I read several years ago.  It was an urban fantasy with Greek gods involved in the plot.  Our protagonist was a magical hacker of some sort, and he had a familiar, a goblin who could turn into a computer with access to magical networks.  Some of the more powerful characters had "troll mainframes."  The primary antagonist was Eris, and she had computers of her own: Apples.  (Yes, the author really went there.)  Does this ring any bells for anyone?


Continuous images of compact sets are compact

Let $X$ be a compact metric space and $Y$ any metric space.  If $f:X \to Y$ is continuous, then $f(X)$ is compact (that is, continuous functions carry compact sets into compact sets). Proof:  Consider an open cover of $f(X)$. Then $f(X) \subset \bigcup_{\alpha \in A}V_\alpha$ where each $V_\alpha$ is open in $Y$. $X \subset f^{-1}(f(X)) \subset f^{-1}\left(\bigcup_{\alpha \in A}V_\alpha\right) = \bigcup_{\alpha \in A}f^{-1}(V_\alpha)$. Hence $\bigcup_{\alpha \in A}f^{-1}(V_\alpha)$ is an open cover of $X$.  Since $X$ is compact then we can choose a finite subcover $\{V_i\}_{i=1}^n$ such that $X \subset \bigcup_{i=1}^n f^{-1}(V_i)$. So then $f(X) \subset f\left(\bigcup_{i=1}^n f^{-1}(V_i)\right) = \bigcup_{i=1}^n f\left(f^{-1}(V_i)\right) \subset \bigcup_{i=1}^n V_i$, a finite subcover of $f(X)$.  $\therefore f(X)$ is compact.  Does this proof have an error? Thanks for your help.


Where are crash logs after a system freeze?

When your entire macOS freezes up and restarts, are there crash logs or core dumps to diagnose the problem? I would in particular like to know which kernel module was active at the time of the crash.  Symptoms: The display "froze", the mouse cursor stopped moving, and the Force Touch trackpad stopped doing clicks. After maybe 10-20 seconds, the system restarted on its own. When it came back up I expected to see a Crash Reporter dialog, which usually has some useful details on the crash, but there was none. I also looked through logs in the Console and couldn't find anything, though maybe I missed something. Is there some place where I should expect to find crash logs?


Synchronize accounts between two Windows computers

How can I automatically synchronize accounts between two Windows (7) computes? I'd like to keep the user-specific information in sync, that means the whole %USERPROFILE% folder.  Those computers may not be always connected to each other, but when they are, the accounts should synchronize automatically.


Swap partition get damaged when encrypted

I upgraded my system to Ubuntu 14.04LTS, I encrypted the home & the swap partition during the installation since it was already encrypted in the old version.  But later I noticed swap partition is not used & using the gparted I found the swaps is damaged, I re-formatted the swap partition as Linux-swap & fixed the UUID in the fstab then cleared the crypttab, then swap was working fine but without the encryption. As soon as I run the ecryptfs-setup-swap to encrypt the swap partition then reboot the system it gets damaged.   This link shows the   Any idea how to fix this?    @muru this is the output, & sda6 is the swap part.  sudo blkid  /dev/sda1: SEC_TYPE="msdos" UUID="5450-4444" TYPE="vfat"  /dev/sda2: LABEL="RECOVERY" UUID="DAAC6031AC600A79" TYPE="ntfs" /dev/sda3: LABEL="WinSys" UUID="E2D0647AD0645737" TYPE="ntfs" /dev/sda5: UUID="96e501a8-40ee-4d08-bcb2-2396a99abd94" TYPE="ext4" /dev/sda7: UUID="348874d5-f654-4640-bbad-0b377e545334" TYPE="ext4"    sudo lsblk  NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT sda      8:0    0 698.7G  0 disk  ├─sda1   8:1    0  39.2M  0 part  ├─sda2   8:2    0  13.2G  0 part  ├─sda3   8:3    0   100G  0 part  ├─sda4   8:4    0     1K  0 part  ├─sda5   8:5    0  42.9G  0 part / ├─sda6   8:6    0  14.3G  0 part  └─sda7   8:7    0 528.2G  0 part /home sr0     11:0    1  1024M  0 rom     Hope its readable now.


I studied Java for a long time and am well acquainted with the operation of generic types in the language : I know there are only at compile time , suffering type erasure at the end of it ( so that at runtime this information is not available ) and have some notion of the difficulties when applying polymorphism on generic types .  Now I am learning C # , and I noticed that although this language use similar notation ( Type  ) semantics does not seem the same . For example , to see that question did the C # runtime stores the information of the generic types instead of discarding it , unlike Java, is that correct? Also, I have never seen an example in C # that utilizes " jokers " ( wildcards ) and type < ? extends TipoGenerico > . This is possible ( or even necessary ) in that language ?  Finally , C # supports individual methods ( not just classes ) generics ? If yes , what is the equivalent syntax of this construction in Java :  public <T> void method (T parameter1 , parameter2 <T> List ) {   If there are any additional details that deserves emphasis , or maybe some reference material to learn more , will also be welcome.


Replace overflow content with "..." with html/javascript/jquery

If you looks at youtube's main page, you can see that the end of every title is replaced by "..." if it haven't finished. I want to do the same.   for example: the sentence "I love going out every day" in a short div might changed to "I love going out every d..."  If the user click "ctrl" + "+" it might change to "I love going out eve...".  How do i archive that?


I'm reading Øksendal's SDEs book and in Theorem 3.2.5 he proves that the Itô integral  $$ \int_0^t f(s,\omega) dB_s(\omega)$$ has a version such that it is $t$-continous. In order to do this he picks elementary functions $\phi_n$, such that $$ E[\int_0^T (f-\phi_n)^2 dt]\rightarrow 0$$ as $n$ tends to infinity. Then he defines $I_n(t,\omega)=\int_0^t \phi_n(s,\omega)dB_s(\omega)$ and states that $I(\cdot,\omega)$ is continous for all $n$. This is crucial to apply Doob's martingale inequality later and gives the statement without proof, but this doesn't seem trivial to me. My question is, why should be the Itô integral $I_n(t,\omega)$ be continous at all? Aren't there going to be jumps as we increase $t$ and more addends appear in the integral?


Magnetic field created by the electron spin

I would like to know if there is some expression for the magnetic field generated by a electron spin.  As far as I know, the spin provides a magnetic moment to the electron and a magnetic dipoles momentum $\vec m$ produces a field:  $H = {1\over4\pi}  \left({3\vec r(\vec m\cdot\vec r)\over r^5} - {\vec{m}\over r^5}\right)$   However, the spin can be measured in each at any direction so, is the previous expression valid for the electron spin?


How to change the forgotten root password?

I forgot my root password...actually I think I know what it is because it is the same password I have for pretty much everything but in the Terminal in tell me "Sorry, try again." Is there a way to reset the password? If so how?


Append Byte[] data into SQLite existing File

Below was actual task:-     Now ,  I have 2 SQLite files with few common tables. File A which I have stored in APK / IPA which I am restoring on App Launch into Actual SQLite DB called File C, and for, File B which I am downloading after user Authentication,  I am trying to Append File B Byte[] to File C,and it successfully appends the bytes but,  However I check file size by browsing the file location after appending the file its size gets increased but,  if I perform select statement on tables which are from file B I am not getting records from the table of it.  I am using FileMode.Append for APPENDING File B byte[] into File C   using (BinaryWriter bw = new BinaryWriter(new FileStream(FilePath, FileMode.Append)))                         {                             byte[] buffer = new byte[2048];                             int len = 0;                             while ((len = br.Read(buffer, 0, buffer.Length)) > 0)                             {                                 bw.Write(buffer, 0, len);                             }                         }


What is fastest children() or find() in jQuery?

To select a child node in jQuery one can use children() but also find().   For example:  $(this).children('.foo');  gives the same result as:  $(this).find('.foo');  Now, which option is fastest or preferred and why?


I remember reading a while ago a series (I think it was a trilogy) about someone born without magic in a world where magic is the norm. I think there was a prophesy that the one without magic would destroy the world or something, so the priests send him into exile and it turns out there are a number of people in exile who have started building machines to combat magic. Other than that, I remember very little, but I think the protagonist comes into possession of a sword that destroys magic and they also play tarot regularly.


.Net Core query case-insensitive string data in list from MongoDb

I have been working out for a case-insensitive search for hours and I still can`t find a solution...  I have data stored in MongoDB and formatted like this :  {   id: 12345,   name: "foo",   area: ["US","California"],   ... }   And I wanna use query to find results, as a list, that area partially matches the area string. For example, if I want to find people who are in us, with lower case. My method looks like this:  public async Task<IEnumerable<Restaurant>> GetByArea(string area) {      var result = await _context.Users           .Find(user => user.Area.Contains(area))           .ToListAsync();       try      {           return result;      }      catch (Exception e)      {           return null;      } }   How should I modify my code to conform case-insensitive search? The IEqualityComparer's methods won't be translated to MongoDB query.


$ \dfrac{2\sin x}{\cos 3x}  +  \dfrac{2\sin 3x}{\cos 9x}  + \dfrac{2\sin 9x}{\cos 27x} = \tan 27 x- \tan x$.  I did not get even to start with which formula. I tried using multiple angle identities but did not find any suitable place to use those. So please help.


I was using Tor completely fine last night in Ubuntu 12.04. I installed TorChat then when I went to use it today I get the following error message.  Oct 15 22:45:57.888 [notice] Initialized libevent version 2.0.16-stable using method epoll. Good. Oct 15 22:45:57.888 [notice] Opening Socks listener on 127.0.0.1:9050 Oct 15 22:45:57.889 [warn] Could not bind to 127.0.0.1:9050: Address already in use. Is Tor already running? Oct 15 22:45:57.889 [warn] Failed to parse/validate config: Failed to bind one of the listener ports. Oct 15 22:45:57.889 [err] Reading config failed--see warnings above.   So I used ps to attempt to kill the running Tor process and found there was none. I restarted the computer and noticed that while loading the OS some text came up very quickly which was the same as this error message. I uninstalled TorChat to see if that was the problem but that didn't do any good. This is the process list  1835 ?        00:00:00 lightdm 1875 ?        00:00:00 gnome-keyring-d 1886 ?        00:00:00 gnome-session 1922 ?        00:00:00 ssh-agent 1925 ?        00:00:00 dbus-launch 1926 ?        00:00:00 dbus-daemon 1939 ?        00:00:00 gnome-settings- 1944 ?        00:00:00 gvfsd 1946 ?        00:00:00 gvfs-fuse-daemo 1953 ?        00:00:01 compiz 1962 ?        00:00:00 pulseaudio 1965 ?        00:00:00 gconf-helper 1967 ?        00:00:00 gconfd-2 1971 ?        00:00:00 gvfsd-metadata 1973 ?        00:00:00 nautilus 1974 ?        00:00:00 polkit-gnome-au 1975 ?        00:00:00 bluetooth-apple 1976 ?        00:00:00 gnome-fallback- 1979 ?        00:00:00 nm-applet 1985 ?        00:00:00 gvfs-gdu-volume 2005 ?        00:00:00 gvfs-gphoto2-vo 2007 ?        00:00:00 gvfs-afc-volume 2028 ?        00:00:00 gvfsd-trash 2030 ?        00:00:00 gvfsd-burn 2036 ?        00:00:00 bamfdaemon 2050 ?        00:00:00 sh 2051 ?        00:00:00 gtk-window-deco 2056 ?        00:00:00 gdu-notificatio 2058 ?        00:00:00 unity-panel-ser 2060 ?        00:00:00 hud-service 2079 ?        00:00:00 indicator-datet 2083 ?        00:00:00 indicator-messa 2084 ?        00:00:00 indicator-sessi 2087 ?        00:00:00 indicator-sound 2088 ?        00:00:00 indicator-appli 2089 ?        00:00:00 indicator-print 2114 ?        00:00:00 geoclue-master 2120 ?        00:00:00 ubuntu-geoip-pr 2133 ?        00:00:00 telepathy-indic 2140 ?        00:00:00 mission-control 2145 ?        00:00:00 goa-daemon 2150 ?        00:00:00 gnome-screensav 2151 ?        00:00:00 zeitgeist-datah 2159 ?        00:00:00 zeitgeist-daemo 2165 ?        00:00:00 zeitgeist-fts 2173 ?        00:00:00 cat 2176 ?        00:00:00 gnome-terminal 2188 ?        00:00:00 gnome-pty-helpe 2189 pts/0    00:00:00 bash 2246 ?        00:00:00 unity-applicati 2249 ?        00:00:00 unity-music-dae 2251 ?        00:00:00 unity-lens-vide 2252 ?        00:00:00 unity-files-dae 2285 ?        00:00:00 unity-musicstor 2314 ?        00:00:00 unity-scope-vid 2328 pts/0    00:00:00 ps   Why would this error message be displaying while booting and is there anything on this list which could indicate that something is running that I haven't picked up and is causing the error?


The book says about mastering a psychic discipline:   Once a psyker has purchased 8 psychic techniques from a single Discipline, he has attained mastery of that Discipline, and the Psy Rating for all Fettered Psychic Strength uses of techniques from that Discipline gain a +1 bonus. This has no additional effect on the Unfettered or Push Psy Rating of the psyker.  But the Telekinetic discipline only has 7 techniques, then how can you attain mastery of that discipline? (Telepathy has 9 techniques, and Divination 8)


c# If else statement with case insensative

I have this if else statement which is assigned to compare results from a text box to a list of context. I am wondering how do i make it such that it is case insensitive ?  value = textbox1.Text;  if (article.contains(value)) {        label = qwerty;  } else {       break; {


Prove that $\{ \sin(x), \sin^2(x), \sin^3(x)\}$ is linearly independent in $F(\Bbb R)$.  I tried plugging in $\left\{ 0, \frac {\pi} {2}, \pi, \frac {3\pi}{2}\right\}$ but that doesn't work. How should I prove this?


It is well known that there is no set of all sets. The argument goes as follows:  Define:  $$\mathcal{C}:=\{X: X\ \textrm{is a set and}\ X\not\in X\}.$$  If $\mathcal{C}$ was a set then $$\mathcal{C}\in \mathcal{C}\Leftrightarrow \mathcal{C}\not\in \mathcal{C}.$$  I am asking myself why this would show there is not a set of all sets.   Well, I think if there was a set of all sets it should be equal to $\mathcal{C}$, right? But this would rely on the fact that every set is NOT a member of itself, but what would justify that?  I am not even sure if I understand the definition of $\mathcal{C}$ anyway.  Can anyone give me further clarifications?  Thanks.


"Premium" means just high cost or is it includes high quality?

Country : India  I have plan to build a web design company. I have to user tag line as something like "Premium Web Design Service" or "Premium Web Design"....  I want to know that "Premium" means just high cost or is it includes high quality too?


Generate random data based on correlation matrix for multiple timesteps

Assume a p x n data matrix  (e.g. p independent samples of n variables). The n variables are correlated according to a correlation matrix $\rho$. Now if you consider the data matrix as some state t (t=time)  and based on this state I would like to calculate the next timestep (t+1). Therefore the correlation matrix would be allowed to have values < 1 in the diagonal, which means that the diagonal elements would indicate the influence from each variable $x_{p,i}[t]$ on $x_{p,i}[t+1]$. So I would be interested to find a function f like this: $x_{p,i}[t+1] = f(x_{p,i}[t],\rho)$ so that the p x n data matrix  consisting of the $x_{p,i}[t+1]$ replicates the $\rho_{ij}$ (except the diagonal element). f should be something like this: $x_{i,j}[t+1] = \sum_{(k=1\ldots n)}\rho_{i,k} \cdot x_{kj}[t] + e_{i,j}.$ This means specifically, I not only want to calculate a data matrix, that replicates the correlation matrix as such, but also to let each observation be depending on its own state and linear dependent on the previous state of all the intercorrelated variables of its own state. For ease one can assume that the p variables are distributed normal and $e_{ij}$ are independent and distributed with mean$(e_{i,j}) = 0 $. Then for a numerical simulation it would be interesting  to find a formula to calculate the variance/standard deviation of each of the j variables (sd($e_{[.,j]} = ?).$ Thank you for any help!


Is it true that Schrödinger wrote his Schrödinger Wave Equation from his mind?

My physics teachers told me that there is no derivation of the Schrödinger Wave Equation and that Schrödinger actually wrote this equation from nothing. He wrote it from his mind. Even in my book there is no rigorous derivation of the Schrödinger Wave Equation. But how is this possible? How did Schrödinger make such a wild guess to such a equation that turns out to be the '$F=ma$' for quantum mechanics? I am pretty sure he hadn't just guessed the equation, right? I mean what are the odds of such a guessed equation to be so fundamentally correct? Why does everyone say that Schrödinger wrote his  Schrödinger Wave Equation from his mind? Why?


How to get the "friendly" OS Version Name?

I am looking for an elegant way to get the OS version like: "Windows XP Professional Service Pack 1" or "Windows Server 2008 Standard Edition" etc.   Is there an elegant way of doing that?   I am also interested in the processor architecture (like x86 or x64).


Is the following proof of $Z(S_n)=\{id\}$ correct?

I wanted to prove that the center of the symmetric group $S_n$, $n\geq 3$ is trivial. Is my argument correct?  Suppose $\alpha\in Z(S_n)$, that is $\alpha\beta=\beta\alpha$ for all $\beta\in S_n$. We can consider, for instance, $\beta_j=(1\,2\dots j-1\,\, j+1\dots n)$ a cycle of length $n-1$ that only fixes $j$ (we know such cycle exists because $n\geq 3$).  $$\beta_j\alpha=\alpha\beta_j\Rightarrow \beta_j\alpha(j)=\alpha\beta_j(j)\Rightarrow \beta_j(\alpha(j))=\alpha(j)$$  so $\beta_j$ fixes $\alpha(j)$, but $j$ is the only letter fixed by $\beta_j$, therefore $\alpha(j)=j$.  Analogously, if we consider $\beta_i$ for any $i=1,2,3\dots,n$ we get $\alpha=id$. Hence $Z(S_n)=\{id\}$.  Thanks in advance!


Can anyone help me with step by step procedure in MATLAB for missing data imputation using Singular Value Decomposition (SVD

I need step by step procedure for imputing data using SVD in Matlab. Please provide resources if any !


I want to charge Lead acid battery (12V, 55Ah) I have adjustable DC power supply (I can set voltage and limit amps). Do I need to put resistor in between power supply and battery? If so.. how much Ω ?


how can I use printf to print a row of minus symbols?  when I try: printf "-----------\\n"  I get:  bash: printf: - : invalid option printf: usage: printf [-v var] format [arguments]   when I try: printf "\-\-\-\-\-\-\-\-\-\-\-\\n"  I get: \-\-\-\-\-\-\-\-\-\-\-


How to concatenate a specific month inside a date variable?

I need to use the month of actual year, something like this  $mid = new DateTime('YYYY-07-01'); // this is where should work the actual year  echo $mid->modify('second monday')->format('Y-m-d');


Suppose $f(x)$ is bounded and differentiable on $[0,\infty)$. Consider the statement: If $\lim_{x\to \infty}f(x)=0 $, then $\lim_{x\to \infty}f'(x)=0 $. Prove it if it's right or show a counterexample.  I think it's not true and trying to find a counterexample by using functions containing $\cos(\frac{1}{x})$ or $e^{-x}$ or other things. The final goal is to find something make it's derivative' limit at infite doesn't exist. Since if it exists, it must equals zero or $f(x)$ will not be bounded.


I have inputs in a form like below. The number in the id/name is the sequence number. The sequence of inputs may be decreased/increased dynamically through jQuery. There is a default number of inputs in the form which will always be an Integer greater than 0.  <select name="r_details-0-ch" id="id_r_details-0-ch"><option value="" selected="">-</option> <input type="text" name="r_details-0-amt" step="0.01" id="id_r_details-0-amt"> <input type="text" name="r_details-0-nar" class="vTextField" maxlength="100" id="id_r_details-0-nar">   <select name="r_details-0-ch" id="id_r_details-0-ch"><option value="" selected="">-</option>  <input type="text" name="r_details-1-amt" step="0.01" id="id_r_details-1-amt"> <input type="text" name="r_details-1-nar" class="vTextField" maxlength="100" id="id_r_details-1-nar">   I want to update id_r_details-{x}-nar via Ajax on change on of id_r_details-{x}-amt where x is a number representing the sequence.  Just for information the form is rendered by Django Admin inlines.  My questions:   How to assign .on('change', ) to id_r_details-{x}-amt. How to then update id_r_details-{x}-narwith return value The value of the specific id_r_details_{x}_ch needs to be passed to the Ajax call. Ch is a select input with options, which I have omitted here for clarity.   EDIT: Need to identify the sequence which fires .on('change, ). Then I think I can do all that needs to be done.


Why use swap when there is more than enough free space in RAM?

Using swap space instead of RAM can drastically slow down a PC.  So why, when I have more than enough RAM available, does my Linux system (Arch) use the swap?  Checkout my conky output below:    Also, could this be the cause of speed and system-responsiveness issues I'm having?  Output of free -m :  $ free -m              total       used       free     shared    buffers     cached Mem:          1257       1004        252          0         51        778 -/+ buffers/cache:        174       1082 Swap:          502        144        357


Do I need to enable the publishing features to change a Team Site's master page?

When building a SharePoint 2010 site, we have a root Publishing site that has been branded up using a custom Master Page.  We'd now like to add some Team Sites below the publishing site, and have our branding and other look and feel changes applied there too, and for that we need to change the "System Master" setting of the Team Site.  The "Master page" options in the site settings are only available if I've enabled the Publishing features in the team site, but I'd rather not do this if I can avoid it.  Ideally, this should be enabled as soon as a new team site is created, without the site owner having to change the site settings.


I would like to install Ubuntu 13.10 on this laptop. I have a USB installation disk. When I boot up with it I get to the menu with option to try Ubuntu without installing. When I select this option screen goes blank.  Specs HP Split 13 x2 PC Processor: Intel Core i5-4202Y 1.60-GHz processor (3.00-MB L3 cache, dual core, 4.5 W) Chipset: Integrated system on chip (SoC) platform controller hub (PCH) Graphics Internal graphics: Intel high-definition graphics Support for HD decode, DX11, HDMI, and PX 5.0 Panel 13.3-in (1920×1080), full high-definition (FHD),light emitting diode (LED), AntiGlare (AG) TouchScreen with MultiTouch enabled; 16:9 wide aspect ratio; typical brightness: 400 nits; slim (3.0-mm), UWVA, support for eDP 13.3-in (1366×768), HD, LED, AG, TouchScreen with MultiTouch enabled; 16:9 wide aspect ratio; typical brightness: 200 nits; slim (3.0-mm), support for eDP


Polynomial is always composite for all integers x.

Let f(x) be a nonconstant polynomial with integer coefficients. Prove that there is some integer n such that |f(n)| is composite.  I'm just a little confused on how to begin. I am fairly certain we start by assuming that f(x) outputs only primes for all integers x, but I don't know where to go from there. Any help would be greatly appreciated.  Thanks!


Close votes for duplicate questions with accepted answers

I'm lately starting to review close votes and many times I see questions that have been voted to close as duplicate, but they have been upvoted and they have a good accepted answer...   If I see such questions I usually vote to keep it open even if it's true that there's another question answering a very similar question...  So, my question is, why to remove them? If it's a good question, and it has at least one good accepted answer, who cares if there's a similar question aout there? Probably the duplicate question has some slightly different details that make it worth to have both question live... or is it that StackExchange's disk space is running out?   Note that I'm talking about good questions, not about the typical horrible and clearly duplicate questions that do no contribute anything new...


First of all, is it a good idea to use FFMPEG as a music mixer? I want to mix audio files of separate instruments to build the music (all wav files and similarly recorded). How can I tell FFMPEG to mix n audio files according to a time map like audio1.wav from 0 to 60s audio2.wav from 3.5 to 18s audio3.wav from 10 to 17s audio4.wav from 61 to 90s


In Illustrator, how do I paste but re-size to fit artboard

In Adobe Illustrator CC (latest version) I often find myself copy/pasting artwork from one file to another.  The problem is the artwork in one file is often larger than the destination Artboard, so I have to zoom out, re-size, then move back onto Artboard ... etc.  Is there a way I can 'smart paste' by telling illustrator to paste it, re-size it and fit it somewhere on the target Artboard?  Any help would be greatly appreciated.  Thank You.


Galois field extension and number of intermediate fields

Given the galois extension $L/K$, where $L=\mathbb{Q}(\zeta, \sqrt[3]{2})$. I've already calculated that $[L:\mathbb{Q}]=6$. I'm trying to prove that the number of intermediate fields is also 6, including $L$ and $\mathbb{Q}$ as intermediate fields. I'm told that the fundamental theorem of galois theory can be useful here, but I can't find a use for it.


Was there some special "badge" awarding moment tonight?

Logged in today, and saw this:  Note: no upvotes today, but 6 badges earned?


What is the best way to remove html tags from an html page? I just want to have the actual text, and not the html tags. I store the text in a string without including the html tags. What is the simplest way to do this? An example page is shown below:  <HTML><HEAD> <META NAME="Docdate" CONTENT="05/02/2011"> <META NAME="m_title" CONTENT="TWO SECURITY GUARDS HACKED TO DEATH DURING A FIGHT"> <META NAME="m_author" CONTENT=""> <TITLE>MALAYSIA NEWS -- GENERAL NEWS -- 05/02/2011 -- TWO SECURITY GUARDS HACKED TO DEATH DURING A FIGHT</TITLE> </HEAD><BODY BACKGROUND="#FFFFFF"> <PRE> 05/02/2011  POLICE-FIGHT  TWO SECURITY GUARDS HACKED TO DEATH DURING A FIGHT          KUALA LUMPUR, Feb 5 (Bernama) -- Two security guards were hacked to death in  a fight that broke out at Damansara Perdana construction site last night.       Both men, aged 20 and 26, were found dead at the scene with slash wounds on  their bodies in the 8.20pm incident.       Petaling Jaya OCPD ACP Arjunaidi Mohammed said the fight started following  an argument involving a security guard and several foreign workers at the site.       "One of them had an argument with several of the workers. He then called two  of his friends who are also security guards but working in other areas.       "A group of 12 to 15 foreign workers, carrying sharp weapons, then attacked  them," he told reporters at the scene today.       The other security guard managed to flee to safety, he added.       "The foreign workers had also left the area. We have picked up a security  guard in the area and two Indonesian workers to have their statements taken," he  said, adding that a manhunt was underway for the suspects.       -- BERNAMA       NMR AKT JS      </PRE> <BODY></HTML>


How should new variables to be added in logistic regression model in production?

We have built a LR model (online SGD ) in Spark. There are more that 15 categorical variables only as independent variables.  At run time new values come in few of the columns.  We have used StreamingLinearRegressionWithSGD of Spark Mlib to build the model.    How should I handle new values in the model at run time? Any guidance would be helpful.    How does model handle the coming of new variables at run time on production in industry? (Irrespective for tool/framework used to build model)?


I have a Logitech M705 mouse and I'd like to configure the extra buttons on Ubuntu. I downloaded the xkeybinds, but I can't make it work. When only 1 key is binded, its fine, but I'd like to make a Ctrl+Page Up & Ctrl+Page Down key too, now that is what not working whatever I trying.  I'd like to bind these buttons: Button 10: F5 Button 9: Ctrl+Page Down Button 8: Ctrl+Page Up  Thanks for the help!


Sort a Map by Key or by value in java  Input Map 1-eee 4-ddd 5-ccc 0-bbb 3-aaa  1st Output Map(By-Key):   0-bbb 1-eee 3-aaa 4-ddd 5-ccc 2nd Output Map(By-Value): 3-aaa 0-bbb 5-ccc 4-ddd 1-eee


I thought it should be because if the logarithmic identities hold then,  $$-\log(-1)=\log(-1^{-1})=\log(-1)$$ But $\log(-1)=i*\pi$ and  $-\log(-1)=-i*\pi$


How do I edit an image in Photoshop so it looks like it was hand-painted like this?

Does anyone have any idea about how to edit like this in Photoshop? I have used Google to search for this, but have found nothing.


Physical mechanism by which the body removes weight during long-term human weight loss

I'm trying to confirm the method by which the body physically loses weight during "long-term" weight loss.  I'm specifying "long-term" here because obviously there are lots of ways to temporarily lose weight.  Loss of water (jogging in the sun while wearing garbage bags to promote sweating?) can potentially lead to quick weight loss, but presumably the body just reclaims that water later.  I'm referring to scenarios where a person, for instance, loses 100 pounds over a course of months via lifestyle changes like exercise and dieting.  When this happens, how does the human body physically remove the weight?  It's long been my understanding that the answer is, effectively, "by breathing it out" (you breath in O2 and breath out CO2, with CO2 weighing more).  This fact has always amused me (it's hard to imagine someone losing 100 pounds one breath at a time).  I mentioned this "fact" to my wife recently and she looked at me very incredulously.  I then realized two things: I had come to this conclusion myself but never actually verified it, and I wasn't sure how to explain the details enough to convince my very dubious wife.  I'm especially curious how much weight is actually lost (on average) per breath, and if there might be other physical processes which contribute to long-term weight loss.  Obviously I'd be especially interested to find out that my expectation is completely wrong!


I know this type of question has been asked before, but in my case my code is different and I have no idea where this NullPointer is coming from.  I am recreating Conway's Game of Life using GridWorld, and I am getting this NullPointerException. I have no clue where it is coming from because looking at the code, it should be working. The act method of this code runs every time GridWorld moves forward a "step". In the first step, the cells are removed and born fine. However, when the second iteration comes, there is a NullPointerException when I try to remove a cell from the grid, when there is a cell there.  int count=0;     public void act() {         if (!isDying) {             count++;             for (Location loc : this.getGrid().getOccupiedLocations()) {                 int nCount = this.getGrid().getOccupiedAdjacentLocations(loc).size();                 if (nCount == 2 || nCount == 3) {                     //Do nothing                 } else if (nCount == 1 || nCount == 0) {                     //Die of loneliness                     if(!deathRow.contains(loc)) {                         deathRow.add(loc);                     }                 } else if(nCount>=4) {                     //Die of overcrowding                     if(!deathRow.contains(loc)) {                         deathRow.add(loc);                     }                 }                 candidateNeighbors = this.getGrid().getEmptyAdjacentLocations(loc);                 for (Location candidate : candidateNeighbors) {                     int cCount = this.getGrid().getOccupiedAdjacentLocations(candidate).size();                     if(cCount==3){                         if(!birthList.contains(candidate)) {                             birthList.add(candidate);                         }                     }                 }             }             isDying=true;         }         else{             count++;             System.out.println("\nAct: "+count);             if(deathRow.size()!=0) {                 for (Location death : deathRow) {                     System.out.println("Death List: "+deathRow);                     System.out.println("Cell to Die: "+death);                     this.getGrid().get(death).removeSelfFromGrid();                 }                 deathRow.clear();             }             if(birthList.size()!=0) {                 for (Location birth : birthList) {                     System.out.println("Birth List: "+birthList);                     System.out.println("Cell to be born: "+birth);                     Cell newCell = new Cell();                     newCell.putSelfInGrid(this.getGrid(), birth);                 }                 birthList.clear();             }             isDying=false;         }     }   When I run the code, this is my console output:  Act: 2 Death List: [(9, 10), (11, 10)] Cell to Die: (9, 10) Death List: [(9, 10), (11, 10)] Cell to Die: (11, 10) Birth List: [(10, 11), (10, 9)] Cell to be born: (10, 11) Birth List: [(10, 11), (10, 9)] Cell to be born: (10, 9)  Act: 2 Death List: [(10, 9), (10, 11)] Cell to Die: (10, 9) Death List: [(10, 9), (10, 11)] Cell to Die: (10, 11) Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException     at apcs.life.Cell.act(Cell.java:54)   Line 54 is this.getGrid().get(death).removeSelfFromGrid(); Thank you for your guys' help!


Update help/on-topic to push Careers onto MSO

SO Jobs (formerly Careers)  primarily. But the  here still says it's on-topic.      If your question is about:      ...                  ...      … it is welcome here.   That should be fixed to stem the tide of misplaced questions here a bit and reduce argufying. (The tag should also be fixed, and I've suggested an edit; there's not much to do about the thousands of old questions, but oh well.)


Conditionally heteroskedastic linear regression: How can I model variance from given predictors?

As a motivating example, consider this hypothesis: A friend and I were discussing how it might be the case that, the more one person is given control in the process of making a movie, the higher the variance of the quality of that film. The more hands that go into making a film, the safer of a bet it is—but the less likely it will be that it is great.  Here are some simulated data that could characterize this hypothesis:  set.seed(1839) x <- runif(1000, 0, 100) y <- rnorm(1000, 0, x) dat <- data.frame(x, y)  library(ggplot2) ggplot(dat, aes(x = x, y = y)) +   geom_jitter() +   theme_light() +   labs(y = "Quality of Film",         x = "Amount of Artistic Control in One Person")     Note that here, I am not interested in predicting the expected value, but the expected variance of $y$ from $x$.  I am familiar with how one can create models for both location and dispersion in beta regression and how one can create models for both location and scale in conditionally heteroskedastic truncated regression.  However, is there a way to model conditional heteroskedasticity in an ordinary least squares regression like this? Are there regression models that exist where one can model the variance of $y$ as a function of $x$? When I try looking for these models, I usually end up with people wanting to use sandwich estimators or weighted least squares or something.  I don't want to treat heteroskedasticity as a problem with the data, but something to be explicitly modeled as a function of predictors $X$. Is there a way to do this with linear regression?


Classification of $n\times n$ real matrices up to congruence

As we known, for matrix similarity $A= P^{-1}B P$, we can classify equivalence class in $M_n (\mathbb{C})$ by .  , $A = P^T B P$ with $P$ invertible, is also an equivalence relation. How does one classify the equivalence classes in $M_n(\mathbb{R})$ under this relation?  For symmetric real matrices, it's easy, since we can use orthogonal transformation to diagonalize it, which gives both matrix similarity and matrix congruence. Then we use a scaling matrix to make the diagonal elements to be $\pm 1$ and $0$. Therefore, for a symmetric real matrix, we classify the matrix by the number of $\pm1$ and $0$. What about for general real matrices?


Windows 10 memory leak research (xperf/WPA) with process "Unknown"

I'm facing a memory leak issue with Windows 10. I've got 4 GB physical memory which is mostly occupied by "nonpaged pool" according to , which sadly cannot be attributed to any single process. Generally, the processes in task manager don't add up to resource usage of such scale (biggest processes have two-figure MB private memory). And it gets worse with growing uptime. Alas, this computer is running in an industrial environment and normally has to be running continuously. Presently, it locks up every few weeks and has to be reset manually.  As per magicandre1981's detailed answer to , I identified the tags FMic and Irp as the main offenders using poolmon ().  After using xperf to record a few minutes of data, in Windows Performance Analyser, the most memory usage under those tags is in the Stack level "n/a" by process "Unknown" ().  The memory allocations under both tags consist of 1 KB chunks or smaller, roughly 600 each (,  detail).  I think it's beyond dispute that there is a memory leak in this system. What else could I try to isolate the offending process or driver?  Thanks and best regards  Björn  EDIT 2018-07-11: Captured the following using WPA.        If the detail isn't deep enough, I can provide the ETL after a little setup work (two days download link).  The offending processes seem to be from "F-Secure Client Security" (memory leak?). Can I do anything else about it, other than complaining to F-Secure?  EDIT 2018-07-16: After removing F-Secure (using Windows Defender now) several days ago, the nonpaged pool is stable at about 200 MB. Problem solved, it seems.


Can we overload behavior of class object

I know we can overload behavior of instances of a class, e.g. -   class Sample(object):  pass s = Sample() print s <__main__.Sample object at 0x026277D0> print Sample <class '__main__.Sample'>   We can change the  result of print s:  class Sample(object):   def __str__(self):     return "Instance of Sample" s = Sample() print s Instance of Sample   Can we change the result of print Sample?


Why does Jesse try to burn down Walt's house despite the tox screen revealing no ricin poisoning

In Breaking Bad, Brock is poisoned by some substance contained in the lily of the valley, as the detectives admit to Jesse as they release him from custody.  First of all, although Walt did indeed get hold of the ricin, he pretends to find it, or a replica, on Jesse's floor, after he convinces Jesse that Gus poisoned Brock.  At that point, in Jesse's mind, Gus poisoned Brock with lily of the valley but wanted him to believe that Walt poisoned the kid with ricin.  Later on, in the final season, realising Huell lifted the ricin (or replica) from his pocket, he shifts over to Walt's house pouring gasoline all over the carpet. But why does he then believe Walt to have poisoned Brock? Has he forgotten about the tox screen results?


Setting task scheduler to run when online

I have my Windows Update set to "never check for updates" on Windows 8.1, but since I still want the Defender definitions update daily, I created a task to get them.  However, I have a question about choosing the appropriate trigger/setting. I want it to run when the computer goes online. Does anyone know how I can set this?


I am having a hard time determining the correct usage when referring to my staff in a sentence.  It includes multiple employees.  Should I say"  Staff were busy this fall or  Staff was busy this fall....  HELP!


Font-face loaded on Windows look really bad. Which fonts are you using that render better?

EDIT: The problem was that I did not have "Cleartype" turned on in my settings on Vista.  This question may not have much meaning if you have Cleartype is installed/enabled on Windows OS.    A new typography wind has arrived on the web, with font-face property of CSS3 be able to load fonts other than the OS/system set. My Mac render many perfectly while my Windows machine doesn't. Which set of fonts should I use that will render better on Windows?    And here an example of a website that looks bad rendered on PC with Myriad Pro:   NOTE: I am not talking about the difference in antialiasing between browser versions (like between IE9 and IE6).  I am expecting as answer by your tests, a list of fonts plus the size (please use px) which they look well, or at least in a way that they can be used for short text or small titles.  For example, at the moment "League Gothic, 30px" looks like the following:


Collision between stationary and moving vehicle

Will it save car from force of front collision with a fast moving vehicle if I put my car in neutral? I am assuming force will only set off stationery vehicle into kinetic motion.


When does Order of Second Partial Derivatives Matter?

My professor was saying that, for a function of multiple variables, usually the order in which you take the order of partial derivatives did not matter. (ex: $f_{xy} = f_{yx}$).  Under what circumstances is this not true?


I'm trying to get the execution time for an algorithm of a java program. I've looked around at similar questions and tried a few ways to do that, but when I print the time lapse I always get 0.  Instant start = Instant.now(); //Method I want to get the exec time Instant end = Instant.now();  System.out.println("\nTime lapse: "+Duration.between(start, end));   Prints:      Time lapse: PT0S   As well as:   Date d = new Date();  long t1, t2;   t1 = d.getTime();  //Method I want to get the exec time  t2 = d.getTime();    System.out.println("\nTime lapse: "+(t2-t1));   Outputs:    Time lapse: 0   Meanwhile, getting the exec time  in C of the exact same method, gives a fair result:  #include <time.h>  clock_t start, end; double time;  start = clock();  //Method I want to get the exec time end = clock();  time = (double) (end-start) / CLOCKS_PER_SEC;   printf("\nTime lapse: %f\n", time);   Outputs:  Time lapse: 0.000004   Why can't I do that in Java?  EDIT  I've tried to use getTimeInMillis() as suggested:  Calendar cal = Calendar.getInstance(); double start = cal.getTimeInMillis();  //Method I want to get the exec time  double end = cal.getTimeInMillis();  System.out.println("\nTime lapse: "+(end - start));   Outputs:  Time lapse: 0.0   FINAL EDIT: Ok so, the program did run in less than a millisecond, that's why I kept getting 0 as a result, and I solved thanks to @Ayo K advice, I used System.nanoTime() to finally get a result.


I'm wondering where a new path has to be added to the PATH environment variable. I know this can be accomplished by editing .bashrc (for example), but it's not clear how to do this.  This way:  export PATH=~/opt/bin:$PATH   or this?    export PATH=$PATH:~/opt/bin


Integer and floating point accuracy in LaTeX3

The L3fp package proposes the range of randint parameters to be +- 10^16 - 1; yet, I seem to be restricted to +-2^31 - 1, any value above it produces the Number too big compilation error. On the other hand I am getting the expected full 16-decimal digit accuracy for fp values. Why?  \documentclass{article} % RN. 15 April 2017 % BRIEF DESCRIPTION: %======================= \usepackage[check-declarations]{expl3} \usepackage{xparse} %----------------------- \ExplSyntaxOn \int_new:N \l_rn_someInteger_int \fp_new:N \l_rn_someFp_fp \NewDocumentCommand\mySetInteger{m}   {     \int_set:Nn \l_rn_someInteger_int {#1}     some~integer:~\int_use:N \l_rn_someInteger_int\\     \int_set:Nn \l_rn_someInteger_int {\fp_eval:n {randint(#1)}}     some~random~integer:~\int_use:N \l_rn_someInteger_int\\     \fp_set:Nn \l_rn_someFp_fp {\fp_eval:n {rand()}}     some~random~real:~\fp_use:N \l_rn_someFp_fp\\     -------------------------------------------\\   } \ExplSyntaxOff %----------------------- \begin{document}     \mySetInteger{1234}     \mySetInteger{2147483647}  %   \mySetInteger{2147483648} %   \mySetInteger{9999999999999999} \end{document}


MainThread unfamiliar process suddenly showing up 18.04

This morning, running top, I noticed a process I nave never seen before in my Ubuntu 18.04 laptop called MainThread, which was periodically using a lot of CPU . There was also an entry called Privileged Cont. I recently installed nordvpn, but nordvpn support said the process is not theirs. Is this a new part of the operating system? Is it malware? It has never appeared in top on my laptop before, as far as I know.


Problem of installing ubuntu 14.o4 in windows 8.1

I have downloaded Oracle VM virtual Box and while creating virtual machine, it was showing only ubuntu 32 bit.It was not showing 64 bit,please help me to solve my problem.


Why I get the "omitting directory" error using globbing in cp command?

I'm trying to copy the "file.txt" file into all the directories.  [root@mycomputer]# ls -lh total 132K drwxr--r--.  2 postgres postgres 4.0K Jan  2 08:47 ilo01 drwxr--r--.  2 postgres postgres 4.0K Jan  2 08:40 ilo02 drwxr--r--.  2 postgres postgres 4.0K Jan  2 08:40 ilo03 drwxr--r--.  2 postgres postgres 4.0K Jan  2 08:40 ilo04 drwxr--r--.  2 postgres postgres 4.0K Jan  2 08:40 ilo05 drwxr--r--.  2 postgres postgres 4.0K Jan  2 08:40 ilo06 drwxr--r--.  2 postgres postgres 4.0K Jan  2 08:40 ilo07 drwxr--r--.  2 postgres postgres 4.0K Jan  2 08:40 ilo08 drwxr--r--.  2 postgres postgres 4.0K Jan  2 10:03 ilo09 drwxr--r--. 11 postgres postgres 4.0K Jan  2 11:15 ilo10 -rw-r--r--.  1 postgres postgres  64K Jun 27  2016 file.txt   Using TAB to see the behaviour of the command to run:  [root@mycomputer]# cp -p file.txt ilo[0-1][0-9] ilo01/ ilo02/ ilo03/ ilo04/ ilo05/ ilo06/ ilo07/ ilo08/ ilo09/ ilo10/   But I get this error:  [root@mycomputer]# cp -v -p file.txt ilo[0-1][0-9]* `postgresTdas.txt' -> `ilo10/file.txt' cp: omitting directory `ilo01' cp: omitting directory `ilo02' cp: omitting directory `ilo03' cp: omitting directory `ilo04' cp: omitting directory `ilo05' cp: omitting directory `ilo06' cp: omitting directory `ilo07' cp: omitting directory `ilo08' cp: omitting directory `ilo09'   Same thing happens with:  [root@mycomputer]# cp -p file.txt ilo*   and  [root@mycomputer]# cp -p file.txt ilo*/   I don't understand why "[0-1][0-9] doen't work the way I need.  I'm assuming that the copy is going to put the file.txt in the list that the TAB shows.  What am I missing?


I was wondering if anybody knows about Latex symbol for an eye, either frontal or lateral view. Frontal:  Lateral:  Update I knew about Detexify and searched there. It didn't work. Detexify took the eyes as some malformed alphabetic characters.


Is the ideal generated by ${4,x}$ a principal ideal in $Z[x]$?

I've : $I=<p,x>$ is not a principal ideal in $Z[x]$ where p is prime. My question :   Is $I=<p,x>$ a principal ideal in $Z[x]$ where p is not a prime? More particularly, is the ideal generated by ${4,x}$ a principal ideal in $Z[x]$ ?


Man marooned on a planet with blind telepathic animals

Which SF short story had a man marooned on a planet with blind telepathic animals and he had to think his way out of trouble? For example, to escape predators he pretends to be a tree but then a woodpecker attacks him...


I know VB.Net and am trying to brush up on my C#.  Is there a With block equivalent in C#?  Thanks


Prove $\exists$ a sequence of polynomials which converges to $f$ on any compact subset of $\mathbb{R}$.

If $f$ is continuous function ($f:\mathbb{R}\rightarrow\mathbb{R}$), then there exists a sequence of polynomials which converges to $f$ on any compact subset of $\mathbb{R}$.  Question: Since $K$ is compact, there exists some interval $[a,b]$, such that $K$ is contained in. By Weierstrass, for all $\epsilon>0$, there exits a sequence of polynomials of $P_n$, such that $P_n$ converges to $f$ uniformly, i.e. $\exists N\in\mathbb{N}$ $\forall n\geq N$, $|P_n(x)-f(x)|<\epsilon$, for all $x\in [a,b]$, therefore, certainly in $K$. So we are done. Correct?


logrotate not able to truncate catalina.out

I'm running tomcat server in my centos machine. I've following content in my /etc/logrotate.d/tomcat file:  /log/apache-tomcat/catalina.out{  copytruncate  daily  size 256M  rotate 8  missingok  maxage 7 }   I tried to run the logrotate command manually in debug mode.  /usr/sbin/logrotate -d /etc/logrotate.conf   In the logs, I found following content regarding the /log/apache-tomcat/catalina.out file.     rotating pattern: /log/apache-tomcat/catalina.out 268435456 bytes (8 rotations)      empty log files are rotated, old logs are removed      considering log /log/apache-tomcat/catalina.out     log needs rotating      rotating log /log/apache-tomcat/catalina.out, log->rotateCount is 8      dateext suffix '-20190206'      glob pattern '-[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]'      glob finding old rotated logs failed      copying /log/apache-tomcat/catalina.out to /log/apache-tomcat/catalina.out-20190206      truncating /log/apache-tomcat/catalina.out   But the file size didn't change after running the command. I'm not sure what went wrong here.  This file size is keep on increasing and causing lot of issues.


Capitalization of job position within a sentence

Should manager and coordinator be capitalized in this sentence?  Representatives from Jonshore's corporate compliance team, package engineering, and their newly revived package testing lab will be in attendance along with BHRS's National Packaging Safety Program manager and the Eastern Region Systems Integrity Safety Program (SISP) coordinator.


How to convert the Laplacian from Cartesian coordinates to polar coordinates?

The Laplacian in Cartesian coordinates is : $$\nabla^{2}=\frac{\partial^{2}}{\partial x^{2}}+\frac{\partial^{2}}{\partial y^{2}}+\frac{\partial^{2}}{\partial x^{2}}$$ And the Laplacian in spherical polar coordinates is : $$\nabla^{2}=\frac{\partial^{2}}{\partial r^{2}}+\frac{2}{r} \frac{\partial}{\partial r}+\frac{1}{r^{2}}\left(\frac{\partial^{2}}{\partial \theta^{2}}+\frac{1}{\tan \theta} \frac{\partial}{\partial \theta}+\frac{1}{\sin ^{2} \theta} \frac{\partial^{2}}{\partial \phi^{2}}\right)$$ I am really sorry if this is a dumb question but I am a mathematics beginner and I am facing a problem. How do we convert the Laplacian from Cartesian coordinates to spherical polar coordinates? There is literally no derivation given in my book as to how it came. Can someone please provide the derivation? Please help. I am really confused.


Fedora won't boot after installing Nvidia drivers

I followed  tutorial about Nvidia drivers installation and I accidentally forget to do 5th point (disabling nouveau drivers), so now I can't boot my system. I know I am idiot but is there anything I can do to fix this?  EDIT  My boot options are (I don't if this is correct or not)  Fedora (3.8.9-200.fc18.x86_64) other two with different version   When I press e to any of these I get lines setparams, then indenticated load_video, setgfxpayload, insmod 3x, set root, then if-else, linux, initrd. There is no line starting with kernel unfortunately.  Ok, I was able to unistall the drivers so I could boot with nouveau again.


I committed a big mistake. I issued the following command on my terminal  sudo apt-get purge python   I didn't read what it removed :(  I use LaTeX typesetting system and some of it's packages are not working now. I've asked my question .  If I've lost the python files, is it needed to reinstall the full OS or something else might help me out of this?    Log -  Start-Date: 2019-08-17  13:55:17 Commandline: apt-get purge python Requested-By: ubuntu (1000) Purge: python-webencodings:amd64 (0.5-2), python-six:amd64 (1.11.0-2), python-matplotlib:amd64 (2.1.1-2ubuntu3), vprerex:amd64 (1:6.5.1-1), python-cycler:amd64 (0.10.0-1), feynmf:amd64 (1.08-10), fragmaster:amd64 (1.7-5), python-xdg:amd64 (0.25-4ubuntu1), python-gi:amd64 (3.26.1-2ubuntu1), latex-cjk-all:amd64 (4.8.4+git20170127-2), python-tk:amd64 (2.7.16-2~18.04.york0), python-tz:amd64 (2018.3-2), python-dbus:amd64 (1.2.6-1), python-chardet:amd64 (3.0.4-1), texlive-pictures:amd64 (2017.20180305-1), python-pyparsing:amd64 (2.2.0+dfsg1-2), python-subprocess32:amd64 (3.2.7-3), python:amd64 (2.7.16-1~18.04.york0), python-lxml:amd64 (4.2.1-1ubuntu0.1), python-enum34:amd64 (1.1.6-2), texlive-xetex:amd64 (2017.20180305-1), qbittorrent:amd64 (4.0.3-1), lyx:amd64 (2.2.4-0ubuntu0.18.04.1), texlive-latex-extra:amd64 (2017.20180305-2), python-cryptography:amd64 (2.1.4-1ubuntu1.3), python-crypto:amd64 (2.6.1-8ubuntu2), texlive-music:amd64 (2017.20180305-2), python-keyrings.alt:amd64 (3.0-1), python-cffi-backend:amd64 (1.11.5-1), python-ipaddress:amd64 (1.0.17-1), python-olefile:amd64 (0.45.1-1), prerex:amd64 (6.5.4-1), texlive-lang-other:amd64 (2017.20180305-1), texlive-full:amd64 (2017.20180305-1), python-scour:amd64 (0.36-2), python-pkg-resources:amd64 (39.0.1-2), python-html5lib:amd64 (0.999999999-1), python-all:amd64 (2.7.16-1~18.04.york0), inkscape:amd64 (0.92.3-1), python-bs4:amd64 (4.6.0-1), texlive-pstricks:amd64 (2017.20180305-2), python-secretstorage:amd64 (2.3.1-2), python-dev:amd64 (2.7.16-1~18.04.york0), python-setuptools:amd64 (39.0.1-2), python-keyring:amd64 (10.6.0-1), lyx-common:amd64 (2.2.4-0ubuntu0.18.04.1), texlive-formats-extra:amd64 (2017.20180305-2), python-idna:amd64 (2.6-1), python-wheel:amd64 (0.30.0-0.2), texlive-science:amd64 (2017.20180305-2), asymptote:amd64 (2.41-4), python-dateutil:amd64 (2.6.1-1), latex-cjk-thai:amd64 (4.8.4+git20170127-2), python-numpy:amd64 (1:1.13.3-2ubuntu1), texlive-extra-utils:amd64 (2017.20180305-2), python-pil:amd64 (5.1.0-1), python-pip:amd64 (9.0.1-2.3~ubuntu1.18.04.1), python-asn1crypto:amd64 (0.24.0-1), python-backports.functools-lru-cache:amd64 (1.4-2), python-all-dev:amd64 (2.7.16-1~18.04.york0) End-Date: 2019-08-17  13:59:03


The question title is vague, because I don't know how to describe my it.   Given the following code:  String getLargeText() {     // loads a large text from somewhere     // and returns it }  Vecor<String> tokenize(String text) {     // seperate the text into tokens and     // return them as a vector of strings }   public static void main(String[] args) {     String text = getLargeText();       for(String token : tokenize(text)) {         // some action with 'token'     } }   Will the 'tokenize' function in the foreach-loop be called at every iteration, or just once and have its return value be re-used? It looks like the kind of thing which a good compiler would optimize, but I am not sure if java does it. And if the answer to the first question is yes, will   for(volatile String token = tokenize(text)) { ...   supress that behaviour?


We have in and out degree of a directed graph G. if G does not includes loop (edge from one vertex to itself) and does not include multiple edge (from each vertex to another vertex at most one directed edge), we want to check for how many of the following we have a corresponding graph. the vertex number start from 1 to n and the degree sequence are sort by vertex numbers.  a) $d_{in}=(0,1,2,3), d_{out}=(2,2,1,1)$  b) $d_{in}=(2,2,1), d_{out}=(2,2,1)$  c) $d_{in}=(1,1,2,3,3), d_{out}=(2,2,3, 1,2)$  I want to find a nice way instead of drawing graph.  for (C):


List controllers are not supported for Order Item

I am trying to create a custom EDIT ALL list button on OrderItem (Order Product) with content source as Visualforce page and am getting below error. I don't want to use standard EDIT ALL button as I want to add some new custom fields to be editable and some fields to be non editable.      Error: List controllers are not supported for OrderItem      Here is my page:  <apex:page standardController="OrderItem"  recordSetVar="EditAllProducts">     ... </apex:page>   Any workaround for this ?


Kernel ridge regression with matrix-vector data set $S := \{ X_i, y_i \}_{i=1}^{N}$?

Background:  For Kernel ridge regression, I have normally come across the data-set given in vector and scalar form, i.e., $\overline{S}:= \{x_i, \overline{y}_i \}$, where $x_i \in M_{n,1}(\mathbb{R})$ and $\overline{y}_i \in \mathbb{R}$. Then, for example, I could do the ridge-regression as given here .    My question:   Can we do the same Kernel ridge regression but with a data set in matrix-vector form, i.e., $S := \{ X_i, y_i \}_{i=1}^{N}$, where $X_i \in M_{n,p}(\mathbb{R})$ and $y_i \in M_{n,1}(\mathbb{R})$? If yes, can you prove it or give me a reference/paper?


In Subversion can I be a user other than my login name?

I'd like to know how to get Subversion to change the name that my changes appear under.  I'm just starting to use Subversion. I'm currently using it to version control code on an XP laptop where I'm always logged in under my wife's name. I'd like the subversion DB to show the changes under my name.  Later on I'll replicate the DB so it is accessible to the whole house. My wife uses the office computer where she is always logged in under my name. I'll probably set it up so that it automatically checks in modified documents... preferably under her name.  Eventually I'll probably be using it from a linux machine under another username.  Is there some way to modify the user environment to change the user name that Subversion calls you? I'd expect something like setting SVN_USERNAME='Mark' which would override however it usually gets the name.  Update: It looks like the --username flag that Michael referred to does work to change the name reported by "svn stat", even for local file: repositories. In addition, it is sticky so you don't need to specify it for the next command. I even rebooted and it still used the "--username" value from my previous boot.


$$\sum_2^\infty e^{3-2n}$$  I only have memorized the sum of at index zero. So I reindex  $$\sum_0^\infty e^{-2n-1}$$  This gives me the sum as  $$\frac{1}{1- \frac{1}{e} }$$  This is wrong. Why?


Let $R$ be an rng. (There may be no unity)  Then, does there always exist a ring(with unity) $A$ such that $R$ is a subrng of $A$?


I rarely use '' ( or ) and use '' () all the time as part of my signature on emails and so forth.  I realize the Swung Dash (⁓) and Tilde (~) are very similar, I just find the longer one more aesthetically pleasing for signatures and stuff like that.  Is there a way I can remap ^ to ⁓ ? Or when remapping keys is it all or nothing?  Any advice is welcomed!   ⁓ Ev   PS ⁓ See, there it is.  Twice.  In the signature and PS!


Real time filtering vs Apply filters button?

We are integrating a BI tool into our maintenance system and I am currently evaluating two viable products to put forward as a recommendation.   One item where these tools differ is their filtering capabilities, one follows the path of selecting criteria and then applying filters altogether. The other updates in real time as soon as a value is selected in the filters.  Are there any viable UX studies or consensus, leading me to believe that one is better suited to a users needs?  The tool would be used on desktop applications only, not phones or tablets.  We will be using 7-8 list style filters, where you can select one or more items from each list like so:


Why do top and lxtask show different degrees of memory usage?

Why does top show 730MB of RAM used, but the "Task Manager" shows 190MB? Some more information on my system:  Lubuntu 14.04 VirtualBox  Screenshots:


How do you calculate drive times around a point?

For example, if I have an Airport point and I want to create a 30-minute Drive Times buffer polygon around it, how would I do that?  I'm currently using QGIS 3.4.4.


Is my airport transit ESTA exceeded by staying in Canada for 6 months? Can I travel back to USA?

I am a citizen of an EU country, currently studying an exchange program at a Canadian university. In January I flew from Berlin to Montréal via Chicago, where I waited 2 hours at the airport before taking another plane to Montréal. For this transit I had to show my ESTA document.  My school will finish this month and I plan to travel in Canada, the US and Peru in the following three months before flying back home to Europe (the end of August). My first entry to the US from Canada will be in June, and it will actually be my first re-entry since the transit at the Chicago airport.   I was wondering if I can enter the US, when basically I haven´t left the ESTA area (USA, Canada) since January? In theory, it means that by staying in Canada (for five months now) I exceed my first entry at the Chicago airport.  Will I be considered as illegal for the US border control when I meet them in June? Can I travel back and forth between Canada and USA later on? Let's say I want to go to Buffalo for three days in June, then come back to Toronto and from there head west to Vancouver and then cross the border to Seattle for a week and then back to Canada.  Will there be a difference between entering the US by plane or bus in this case? Finally, and most importantly in July, I am going to fly from Canada to Peru for three weeks with a probable transit at an US airport. From Peru I will fly to the US and stay there until flying back to Europe from NYC. This will be my fourth entry to the US since Buffalo, but still in in the 90 days limit. Is that OK?     I will always carry with me my EU passport, the ESTA document, the flight ticket home (August 30th, NYC-Berlin), and a confirmation of study at the Canadian university.   Here's the rough schedule:     1/15 Chicago (transit to Canada) – 6/15 Buffalo (3days) – 6/30 Seattle (7days) – 7/15 Houston (transit to Peru) – 8/5 Houston (back from Peru) – 8/30 leaving the US.


USB security token (not storage) from bank: VirtualBox does not see it

On Mac I inserted this USB key into Apple Cinema Display with USB port (my MacBook Pro only has USB-C ports) and it worked with VirtualBox. Now I trying to connect this USB key to the virtual machine with Windows on another host machine, with Linux. On the screenshot - log from dmesg, looks like my Ubuntu 16.04.4 i386 see it, but VirtualBox from repository not. Also I installed virtualbox-ext-pack that required for USB 2.


Selection Tool doesn't rotate in Illustrator

Why my selection tool doesn't rotate object? I selected the object and it doesn't work. How do I fix this?


Why is the Croatian football team so successful despite having a population of only 4 million people?

Not only did they crush Argentina by 3-0 in this 2018 world cup, they also humiliated another traditional 'football power' England and made it to the finals despite their population being less than ten percent that of England's and despite not having the high profile soccer leagues that the other countries have. What is their secret? I am sure it isn't just luck.


How do I move a line following match up to the end of previous line?

I have about 500 files of text files similar to the output below.    GigabitEthernet15/0/ 1                                                                GigabitEthernet16/0/ 1                                                                GigabitEthernet16/1/ 1                                                                GigabitEthernet15/1/ 1   My goal is to have it look like this:  GigabitEthernet15/0/1                                                                GigabitEthernet16/0/1                                                                GigabitEthernet16/1/1                                                                GigabitEthernet15/1/1


Let $a, b, c, d\geq 0$ s.t. $a+b+c+d=4$.  Show that $(a^2+3)(b^2+3)(c^2+3)(d^2+3)\geq 256$.  I don't know how can I deconditioned the inequality.


How does conservation work in wormholes?

My questions might seem naive as I haven't plunged into the mathematical descriptions, but wormholes are interesting even if I don't actually know them :)  First of all, is wormhole making two possible paths betwwen points (like the tunnel in most visualisations) or is it just making two points beside each other like in the game Portal? Of course, second case can be bent into a tunnel, but there would be nothing special about tunnel part and no preferred way to divide into "normal" and "tunnel" part of spacetime.  My main questions are these:   Is momentum conserved? Is kinetic energy conserved? How does potential energy work?   To elaborate... In the game Portal you can fall into floor and fly out of the wall or floor elsewhere with the same speed, but another direction (normal to the portal). So momentum is not conserved, but kinetic energy is. Is that how it would actually work? Where does the momentum go then?  And does it really allow you to increase your potential energy while retaining kinetic? It would seem fair to take away some kinetic energy if you are put in a region where you have more potential energy.  Either way is the change in energy non-continuous like in the game and discussion that's linked below? Or are there just more than one way to move through but the change in potential energy is smooth in any of those? That would mean more potential equilibrium points though...  Similar questions has been discussed , is it correct about how the falling guys gets a lot of energy (in form of a potential one) by draining it from the mouths?


How do I center an image with a width less than 100%?

When I have display as 100%, everything displays fine, but I'd like to have the image a little smaller so I've set the width as 30% for now - the issue with this is that the image stops centering once I do that (would anybody know why that's the case?). If I remove display block, it centers, but then sits on the same line as the button - however if I then add in display:block to the button, the left/right padding stretches across the width of the container. Here's the codepen where I've saved my project:  - but here's the code I'm having trouble with: .image {     margin-bottom: 25px;     width: 30%;     border-top: 1px solid #cee5d0;     display: block; }


Why was the ending of the book different from the ending of the movie in regards to the Elder Wand?

I was watching the film "Harry Potter and the Deathly Hallows part 2" in which Harry broke the Elder Wand. However, in the book he put the wand back inside Dumbledore's grave.  Why was this changed in the film?


Why/how was this (non wiki) suggested edit orphaned?

Reviewing , I hit Improve Edit and further updated the post.  Now the suggested edit is "orphaned".  It shows in :        but not in : (History for all users is shown. You need 10K to see it using the link.)         And  shows just the Community User:        when it should also show the reviewing user. For example:         So, how did this suggested edit get orphaned? I've seen this a few times now over the years.    PS: If it's not obvious, I am user Brock Adams on Stack Apps.


I ordered online for a Lenovo 65W AC adapter for Lenovo G550 laptop.  My original adapter had specifications: 19V 3.42A (64.98W)  While the one I got has specifications: 20V 3.25A (65W)  I want to know if it is safe to use the second adapter with my laptop.  Edit 1: The new adapter is also from Lenovo.


Hint for problem including function of random variable?

If $Y=\frac{\ln(U_1)}{\ln(U_1)+\ln(1-U_2)}$ where $U_1,U_2$ are independent $U(0,1)$ random variables, then variance of Y equals.  I usually use Jenson's inequality to underestimate or overestimate expectations of function of random variables (of any distribution ) but this is something different here the question is asking for the equality of variance how to do such questions thanks. Please suggest tags if they are not proper.


Unknown encoder 'libmp3lame' in Ubuntu 14.04

I'm running Ubuntu 14.04.1 LTS. The question looks like this , but I followed everything there and installed every package they mentioned but still I am getting the error.  I am trying to convert FLAC to MP3 using ffmpeg, with below command:  ffmpeg -i hang_drum.flac -acodec libmp3lame destination_path.mp3   Error:  ffmpeg version 2.3.3 Copyright (c) 2000-2014 the FFmpeg developers  built on Sep  5 2014 17:58:33 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)   configuration:    libavutil      52. 92.100 / 52. 92.100   libavcodec     55. 69.100 / 55. 69.100   libavformat    55. 48.100 / 55. 48.100   libavdevice    55. 13.102 / 55. 13.102   libavfilter     4. 11.100 /  4. 11.100   libswscale      2.  6.100 /  2.  6.100   libswresample   0. 19.100 /  0. 19.100 Input #0, flac, from 'hang_drum.flac':   Metadata:     TSS             : Logic 10.0.6     ENCODER         : Lavf55.44.100   Duration: 00:02:36.06, start: 0.000000, bitrate: 627 kb/s     Stream #0:0: Audio: flac, 44100 Hz, stereo, s16   I tried:   sudo apt-get install ffmpeg libavcodec-extra-53 sudo apt-get install ffmpeg libavcodec-extra-54 sudo apt-get install libmp3lame0 sudo apt-get install libav-tools:i386 sudo apt-get install ffmpeg libav-tools   After running these, I'm still getting the same error libmp3lame. What am I missing here?


Let $a \in \mathbb{R}$ and $\lim b_n = b$ (for a real sequence $b_n$). I am trying to show that $\lim a^{b_n}=a^b$ by using the definition of the convergence of a sequence, but I cannot see how to estimate $|a^{b_n} - a^b|$ against $|b_n - b|$ properly.


Difference between cp -r and cp -R (copy command)

cp -r is meant to copy files recursively, and cp -R for copying directories recursively. But I've checked, and both appear to copy both files and directories, the same thing. So, what's the difference actually?


How do I include greek symbols in a beamer presentation

I can't seem to insert Greek symbols in my beamer presentation. This is how the top section looks like  \documentclass{beamer} \setbeamertemplate{navigation symbols}{} \usepackage{beamerthemeshadow} \usepackage{ragged2e} \usepackage{amsmath, amsthm} \newtheorem{exercise}[theorem]{Exercise} \newcommand{\exinline}[1]{(\refstepcounter{theorem}Exercise~\thetheorem\label{#1})} \usepackage{listings}%% to include code \lstset{     language=Java, basicstyle=\footnotesize\ttfamily,     keywordstyle=\footnotesize\color{blue}\ttfamily,  }  \addtobeamertemplate{block begin}{}{\justifying} \setbeamercovered{transparent=15} \begin{document} %here is a sample page \begin{frame}    \frametitle{Trial insert Greek Symbols}      \begin{itemize}         \item<1> \epsilon         \item<2> Some text      \end{itemize}    \end{frame} \end{document}   Whenever I remove the \epsilon, my file compiles without error. When I add the \epsilon it produces this error  "!Missing $ inserted. ,inserted text> $ \end{frame}" Also is there any specific arrangements when including a package in the latex file (E.g. A certain package should be above some other package while including in a file).   Regards


How do I clear the information in the "lightning: input" fields?

I have fields in a popup form of a page, thanks to which I add a new object to the database. But after adding or canceling, the information in the filled fields is not cleared. How should I do it? Do I need to clear the information in the fields myself by filling them with empty value or is there a way to clear it automatically?
                                 <lightning:input aura:id="contact"                                                  label="First Name"                                                  value="{!v.contact.FirstName}"/>                                 <lightning:input aura:id="contact"                                                  label="Last Name"                                                  value="{!v.contact.LastName}"                                                  required="true"/>                                 <lightning:input aura:id="contact"                                                  type="email"                                                  label="Email"                                                  pattern=".+@.+.com"                                                  placeholder="username@example.com"                                                  value="{!v.contact.Email}"                                                  required="true"/>                                                                      <lightning:combobox aura:id="contact"                                                     label="Contact Level"                                                     placeholder="Select contact level"                                                     value="{!v.contact.Contact_Level__c}"                                                     options="{!v.contactLevel}"                                                     onchange="{!c.selectContactLevel}"/>                                                                  <lightning:combobox aura:id="contact"                                                     label="Account"                                                     placeholder="Select account"                                                     value="{!v.contact.AccountId}"                                                     options="{!v.accounts}"                                                       onchange="{!c.selectAccount}"/>                                                              Contact ID after saving :                                  <lightning:formattedText title="Contact Id" value="{!v.contactId}"/>
                                 <lightning:button label="Create" class="slds-button slds-button_brand slds-m-top--medium" onclick="{!c.saveContact}"/>                                 <lightning:button label="Cancel" class="slds-button slds-button_brand slds-m-top--medium" onclick="{!c.cancelNewContact}"/>


Is there a word for laughing when faced with a hopeless situation?

A word for the unexpected reaction of laughing in a situation of complete hopelessness or laughing with sad undertones


What does syslog entry Memory pressure relief indicate

My syslog file is has large number almost continuous entries as follows.  Apr 13 11:49:40 nrao-XPS-8700 gnome-session[2439]: Memory pressure relief: Total: res = 9682944/9682944/0, res+swap = 0/0/0 Apr 13 11:50:05 nrao-XPS-8700 gnome-session[2439]: Memory pressure relief: Total: res = 12369920/12369920/0, res+swap = 0/0/0 Apr 13 11:50:07 nrao-XPS-8700 gnome-session[2439]: Memory pressure relief: Total: res = 10633216/10690560/57344, res+swap = 0/0/0 Apr 13 11:50:10 nrao-XPS-8700 gnome-session[2439]: Memory pressure relief: Total: res = 9682944/11800576/2117632, res+swap = 0/0/0 Apr 13 11:50:35 nrao-XPS-8700 gnome-session[2439]: Memory pressure relief: Total: res = 12369920/12369920/0, res+swap = 0/0/0   Output of free -m command is follows                total        used        free      shared  buff/cache     available Mem:          15998        7155        5903         113        2939        8323 Swap:         18477        4182       14295


I am trying to install Ubuntu 12.10 for quite some time, and passing hurdles one by one. Now I am in a situation as follows.  I have got a PC and 10 GB HDD which will be totally dedicated to Ubuntu so no option of Wubi and dual boot.  I was trying to install from DVD, but it is getting stuck at "Out of frequency" error. So I had to adapt for USB boot option. But my PC is USB non bootable, so workaround is "Plop Boot Manager". So I am doing the installation procedure as follows:   starting  from a CD drive which is having plop installed. opting for for USB boot in plop options. booting begins from USB. monitor eventually gives "out of frequency" error press Shift+Alt+F1 to get the terminal. open the grub with sudo nano /etc/default/grub. do necessary changes. sudo update-grub.   Now here I am getting error as follows:   /usr/sbin/grub-probe:error:failed to get canonical path of /cow.     My system is   P4 3.06 GHz, 1 GB ram , 10 GB HDD without an OS, monitor CRT lg StudioWorks (7 years old). Mobo Mercury P4 266a NDMx (865 equivalent). The whole system is perfectly in working condition under XP, but it is USB non bootable, and all other devices working perfectly.  What should I do next?


$m$ is a perfect square iff $m$ has an odd number of divisors?

Is this proof that $m$ is a perfect square iff $m$ has an odd number of divisors correct?  $\Rightarrow)$ If $m$ is a perfect square there is an $x$ such that $x = m/x$.   The rest of the divisors come in pairs $d, m/d$, so $m$ has an odd number of divisors. $\Leftarrow)$ Again, divisors come in pairs $m, m/d$   If there are an odd number of divisors, then necessarily $m/d = d$ for some divisor $d$, so $m$ is a square.


Can I transfer saved data from my old PS3 hard drive to my new PS3?

A while ago, my PS3 completely broke. Every time I turn it on, it just completely shuts down a few seconds later. I decided to buy a new ps3 to play my old games. The problem is that I don't have my saved data, but I still have the original hard drive. Is it possible to somehow transfer the saved data from the old hard drive to my new PS3? I was thinking maybe I could clone the hard drive, but I don't have a spare hard drive to do it on. I do however have a 2 TB external hard drive. Would it be possible to clone it on the external? Are there any alternative methods?


Weird multiplication issues, converting float to int

I'm currently trying to convert a floating point value to an integer while preserving the decimals(long story short user input needs to be in decimal form but I can't keep the variable as a floating point because rounding errors). I do this with this code:  c = initial * 100;   In this example, "c" is the int and "initial" is the floating point. The problem is, C will get the very basic multiplication wrong somehow, 4.2 returning as 419 instead of 420. I don't really know how to fix this - I assume it must be another issue with floating point rounding errors.


Recommendations for a network monitoring data counter?

Is there a graphical data counter for Ubuntu that records how much uploaded/downloaded data was used and bandwidth being used and total amounts, filtering it by application?


If $a_{1}=1$ and for n>1, $a_{n}=a_{n-1}+\frac{1}{a_{n-1}}$ , then $a_{246}$ lies between two integers, what are they?


Well a silly question to ask, shall we consider *shoes * as singular or plural? I would say that it is plural for it has a singular form shoe.   But then why do we write Either my shoes or your coat is always on the floor ?


Optimization problem for maximum volume of inscribed figure.

While studying, I came upon  this problem: "What is the largest possible volume a right circular cylinder can have if it is inscribed in a sphere of radius 5?" The answer was shown as (500*pi)/(3*sqrt(3)). The explanation simply told me to find and substitute a volume equation, then use derivatives. I did not fully understand this problem with this short explanation. Could someone offer a detailed explanation to this problem?


How do I approach questions on finding integral solutions?...like this one

Find all positive integers a, b such that each of the equations $x^2 - ax + b = 0$ and $x^2 - bx + a = 0$ has distinct positive integral roots.  My approach was to use Vieta's formula, Taking $p, q$ as roots of first equation and $r, s$ as roots of the second equation. then, $p + q = a$ and $pq = b$ $r + s = b$ and $rs = a$  Then I'm stumped... I'm unable to proceed after this point. What do I do after this, or this is completely a wrong method.  Please help me figure this out. Any help would be appreciated.


Help me remember a 90s or 80s scfi parody like galaxy quest but not galaxy quest

So from what I remember it was on cable TV. The main hero was a TV actor zapped to a alien planet. It had a evil overlord with a virgin priestesses. She wants to get laid but he refuses because the next priestesses is only three. Regardless it's a parody things include a man who was maimed by the evil overlord wants revenge the hero eventually screws the virgin priestesses it cuts to scenes of a train going into a tunnel and a volcano erupting.


It would seem to a naive eye that if you have a MAC, you have a hash function: use a key that all the parties know (such as all-bits-zero).  A potential application would be a resource-constrained platform where code size is at a premium, and which needs to implement AES for confidentiality: instead of also implementing SHA-2 for integrity verifications, it could use e.g. AES-CMAC.  Is there a reason not to do this? Is the existence of hash functions alongside MAC due to security? Performance? History?


Continuous compactly supported real valued functions on a locally compact and $\sigma$ compact space is separable

I already know that if $X$ is a compact metric space then the space of continuous real valued functions $C(X \to \mathbb R)$ are separable. What I'm trying to prove that if $X$ is a locally compact metric space and is $\sigma$-compact. The space of continuous compactly supported functions $C_c( X \to \mathbb R)$ are separable.    Here's my approach: As $X$ is $\sigma$-compact, we can write $X = \bigcup_{ n=1}^\infty K_n$, where $K_n$ are compact and increasing. Then since each $C(K_n \to \mathbb R)$ is separable, it suffices to show that the set $ \{ f \in C_c (X \to \mathbb R) : \operatorname{supp}(f) \subset K_n \}$ is dense in $C(X \to \mathbb R)$ (Not sure). Then get I stuck.  Any help is appreciated.


As you know, backtick ( ` ) is needed to mark down the code blocks when writing any answer / comment in stackoverflow or any other stackexchange sites. But I am struggling to find out the key to write backtick when using my iPhone.   I am new to iPhone and using iPhone 6s. Thanks for your help in advance.


How to have duplicate display on ubuntu 14.04 with gnome

I have ubuntu 14.04 wtih GNOME shell I am unable to have duplicate display. In my display setting I just can extend or disable or enable one display but there is't any duplicate option in display setting. So how can I have duplicate screen in both my device?


It is a generalized linear model with a linear combination of covariates related to the response via a canonical link function.   Why weibull distribution is not a glm?


Screen brightness isn't taking effect on a Lenovo Z570

My Lenovo Z570 has two GPU's, nVidia and Intell. Brightness control has no effect what so ever over the screen brightness, and because I've had some major issues in the past when I was trying to fiddle with nVidia drivers and settings, and I wanna be cautious now. I haven't find similar questions referring 14.04 LTS with similar configuration as mine.   I've read that it could be fixed by adding/changing content in xorg.conf but when I run  sudo gedit /etc/X11/xorg.conf   the file comes out to be absolutely empty. What do I need to do, what do I need to add to it and not get my laptop screwed with a black screen again?


Dedicated meta sites vs. Meta Stack Exchange

Each Stack Exchange site has its own, dedicated meta site. I just asked by myself, why not one meta site for all Stack Exchange sites?  I suppose that many questions have cross site duplicates and for specific questions it would be possible to introduce site specific tags. Are there technical constraints or is it more likely design decision?


Why is vote time missing in the SE data dump and SEDE?

Is there a particular reason why vote times are omitted in the data dump?  IMO this could be a very useful data-set. Is this one of the steps that was done to anonymize the data, or does it simply not exist? This would be a very good addition to future dumps to help build time-based relationships, which are currently very rigid and full of assumptions.


"Your edit must be at least X characters" is problematic at Code Golf

Many times when I try to edit an answer with things like "Improved formatting" I am prohibited from doing so due to the "Your edit must be at least X characters" prompt. I understand why a rule like that exists on most SE sites. However on some sites like codegolf.stackexchange.com answers are, by nature, hardly any amount of characters long.   This answer, for example, is very small:   The headline format is not within the regular formatting of the site (Code language and byte count should be bolded with the preceding #-operator.  But I can't edit the post because just making the change does not change enough characters, and I don't want to add random characters just to make the edit do-able (though that is something I see done frequently to bypass this 'rule').  Perhaps the "at least X characters" rule should have a dynamic X based on original post length. If the answer itself is only 30 characters, maybe the the 'X' should be 5; but if the answer is 200 characters then X can be 10 or whatever it is.  What do you guys think?


Mobile website menu. Should hamburger menu be on left or the right?

Quite a while ago we decided to move our hamburger menu (I know they are evil but we got stupid amount of subcategories) to the right. Reasoning behind that was based on accessibility and in indoors labs it proven that people preferred it this way.   Now we are doing some reworks regarding mobile top banner and search. While doing research I noticed that literally all of our competitor has their hamburger menus on the left.   Is it worth sacrificing usability (way easier to reach menu) for consistency (everyone one else is having their hamburger menus on the left).  It is worth noting that our customer base is heavily using mobile devices especially iPhones.  There is similar topic but I dont think it covers particular use of hamburger menu location on websites, and not apps.


I want to add a landscape page between 2 pages, But the problem is that latex make a space before landscape, how to remove the section (which circled on red ) to the page 1. the code is like that Text   \afterpage{ \begin{landscape}  a  \end{landscape} }  \Section  Another text


I'm currently in the process of learning Java. I have just run the following line in Eclipse in Win7 using jre1.8.0_25:  System.out.println(4.5 * 7.9);   The console output is: 35.550000000000004  I'm just wondering why the output is wrong.


I have crontab setup on my CentOS VPS and it is not running...  Here's the cron file:  * * * * * php -f /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/1min.php * * * * * php -f /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/1minemail.php */15 * * * * php -f /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/15min.php */30 * * * * php -f /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/30min.php 0 */1 * * * php -f /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/hourly.php 0 0 */1 * * php -f /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/daily.php 0 0 */7 * * php -f /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/weekly.php 0 0 */30 * * php -f /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/bimonthly.php 0 0 * * * php -f /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/clearreport.php   I've also tried another variation of that:  * * * * * php -q /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/1min.php * * * * * php -q /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/1minemail.php */15 * * * * php -q /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/15min.php */30 * * * * php -q /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/30min.php 0 */1 * * * php -q /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/hourly.php 0 0 */1 * * php -q /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/daily.php 0 0 */7 * * php -q /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/weekly.php 0 0 */30 * * php -q /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/bimonthly.php 0 0 * * * php -q /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/clearreport.php  * * * * * php -q /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/1min.php * * * * * php -q /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/1minemail.php */15 * * * * php -q /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/15min.php */30 * * * * php -q /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/30min.php 0 */1 * * * php -q /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/hourly.php 0 0 */1 * * php -q /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/daily.php 0 0 */7 * * php -q /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/weekly.php 0 0 */30 * * php -q /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/bimonthly.php 0 0 * * * php -q /var/zpanel/hostdata/zadmin/public_html/pingrglobe_com/crons/clearreport.php   I am able to run the files from my web browser, but not from crontab.


"returns" or "is returning", which one of the followings is true?

The question is, "Fay ------ from her holiday tomorrow evening." Fill the blank with "is returning" or "returns".  Which one would be true if used?


which analysis fit the best for the data?


Generating and solving recurrence relations

I am trying to do this question but don't know where to go from here: The question: For $n\ge1$ let $t_n$ be the number of ways to tile the squares of a 2xn checkerboard using 1x2(which can be rotated to be 2x1 tiles) and 2x2 tiles, if the 1x2 tiles come in 5 different colors and the 2x2 tiles in 4 different colors. Find and solve a recurrence relation for $t_n$.  I think I first part of 1x2 tiles to be : $t_n=3t_{n-1} +9t_{n-2}$  Is that part right? and how do i go from here


Prove a composition of two functions is meaurable

Let $f,g:[0,1]\rightarrow [0,1]$ be measurable functions.Is $g\circ f$ measurable or not?  The composition is definitely measurable from the axiom definition of measurable function. But if we want to prove it from the classic definition of measurable function,we have to prove that preimage of an open set of this composition is measurable. In order to do that,we have to prove that the preimage of a mesurable set by a measurable function is a measurable set.Now I don't know what to do with the mesurable sets in $[0,1]$ except for the Borel sets.