I have this templated function inside a class. This is implemented in a file named Mtry.cpp  class Mtry { public:     template <typename DerivedV, typename DerivedF, typename Scalar>     static void cotmatrix(         const Eigen::MatrixBase<DerivedV> & V,         const Eigen::MatrixBase<DerivedF> & F,         Eigen::SparseMatrix<Scalar>& L); };    template <typename DerivedV, typename DerivedF, typename Scalar> void Mtry::cotmatrix(     const Eigen::MatrixBase<DerivedV> & V,     const Eigen::MatrixBase<DerivedF> & F,     Eigen::SparseMatrix<Scalar>& L) {     // Implementation... }   I have no problem when using that code. However, if I move the declaration towards Mtry.hpp and the implementation to Mtry.cpp I get an undefined reference  Mtry.hpp:  class Mtry { public:     template <typename DerivedV, typename DerivedF, typename Scalar>     static void cotmatrix(             const Eigen::MatrixBase<DerivedV> & V,             const Eigen::MatrixBase<DerivedF> & F,             Eigen::SparseMatrix<Scalar>& L); };   Mtry.cpp  template <typename DerivedV, typename DerivedF, typename Scalar> void Mtry::cotmatrix(     const Eigen::MatrixBase<DerivedV> & V,     const Eigen::MatrixBase<DerivedF> & F,     Eigen::SparseMatrix<Scalar>& L) {     // Implementation... }   I saw  where it states that the first code should work. However I couldn't find how to separate the code properly into header and source. How should it be done?

Quote from :     The only portable way of using templates at the moment is to implement them in header files by using inline functions.   Why is this?  (Clarification: header files are not the only portable solution. But they are the most convenient portable solution.)


I found a number of questions on Meta relating to revenge downvoting, but most of them were discussing the situation in which a user suddenly receives a deluge of malicious downvotes. My situation is different — a single, tit-for-tat downvote in direct response to me downvoting their post, which the other user explicitly admitted in a response to my comment:  me: [explains why their post didn't adequately answer the question] them: [correctly inferring that I downvoted them] "I downvoted your question too then."  I won't lose too much sleep about the -2 rep, but this is clearly not how downvotes are supposed to be used. What's the best response to this situation, or should I simply ignore it?

I have a situation where I'm trying to figure out what the right thing to do is on SO.    I see a question.  I answer the question.  I see there are a couple other answers.  One answers the question well, though with less explanation than my answer.  The other answer seems both wrong and irrelevant to the question (doesn't answer the question at all).  I comment to that effect.  The "wrong" part is edited out, but the author of the answer doesn't respond to how their answer actually answers the question.  In fact, they seem offended that I don't "get" it.  After giving them several chances to explain how their answer is relevant to the question and seeing their attitude, I decide to downvote their answer as I don't see how it addresses the question at all and the author won't explain.  They retaliate and downvote my answer and admit in their comments that their downvote of my answer has nothing to do with the content of my answer and only because they don't like me disputing their answer.  Did I do the right thing by downvoting their answer?  Do I just have to live with their downvote retaliation?  Anything I should have done differently?  I also have no way of knowing this for sure, but the next question I answered was upvoted, then downvoted so perhaps this same person is stalking my answers and downvoting other answers of mine too with no comment.  As long as this doesn't continue, I'm not losing sleep over a couple downvotes, but I do wonder if I should have done anything differently.  Followup Later After I Posted This Question: After thinking about it for a little while, the person who disagreed with me decided to delete their post.  So, eventually the message did get through to them.  I don't know if they rescinded their downvote or not (or if they even could).


I use the virtual desktops. They are really handy. Frequently, I leave something that takes some time to load/render/process running in a virtual desktop and then I switch to another to do other work. And to see whether the first task has finished or not, I usually hit SUPER+S just to have an eagle's view on the state of the processing [on the other desktops]. However, doing this I have to stop whatever I'm doing.  That's why I was wondering if is there any way that would give me such view [on just one other desktop, doesn't need to be able to see all the others] without having to [interrupt what I'm doing at the moment and] hit the SUPER+S? You know, a quick glance of eyes would do the trick; switching desktops (even using the handy shortcut CTRL+ALT+directional arrow makes my mind 'shift context' and thus loosing the focus)...  (I know that having two monitors would do the trick, but I don't have a fixed desk, hence have to rely only on the notebook I carry to everywhere... (sigh!))

Is it possible to mirror a live section of one workspace so that it is visible in the current workspace as a window that can be moved around?  The other day I had a Windows 10 VM running on my Ubuntu 16.04 host that took a really long time to complete updating.  I kept checking on its progress via Expo (Super+S) on Ubuntu.  That got me thinking that this problem has most likely been solved already since tools such as simplescreenrecorder can be configured to record just a portion of the screen.  However, I don't know the proper terminology to use for my Google search.  I'd like to see the 300x150 screenshot below in the form of a floating window (with live updates) in the top right corner of whichever workspace happens to be current.


My application is "authorisation pending" after 7 days.  What can I do?  I visited Kurdistan on UK government business and declared it honestly.

As a British citizen, I recently applied for an ESTA visa waiver in order for me to travel to and present at an academic conference in the United States. To my surprise, they have added additional criteria based on travel to certain countries in the Middle East since 2011 (this change was apparently made in December 2015). I stated on my application that I had worked as a lecturer at a specific institution in the Kurdish region of Iraq for a three month period. I expected my application to be denied fairly quickly (although I hoped that it wouldn't) but having checked it several times, there has been no change to the "Authorization Pending" status when I check my application on the website. The top of the page (when I check my status) says:     Your travel authorization is under review because an immediate determination could not be made. This response does not indicate negative findings. A determination will be available within 72 hours.   It has now been 18 days since I applied - I understand that they may want to check my details more thoroughly and am more than happy for them to - but through various searches on google, I have been unable to find anyone else who had waited so long for a response!  Is it possible for the applications to get stuck in the system? Or is it far more that they're spending this time trying to determine whether I am a security threat? I've heard of people putting in a second application when the first takes a long time - would this be advisable?  Thanks for your time!  EDIT - Adding this from an answer posted by the OP  My status has officially changed today (20 days after application) and I have been declined the Visa Waiver.  Since the conference is in a month's time, I can still apply for a B-1 Visa but probably won't. Looking at the visa application website, it may be the case that I'll be asked to report my travel history over the past five years and although it's relatively uninteresting, I really do not have the time to put together all the documentation they might ask for, nor can I really be bothered to go through the rigmarole of an interview in London.


I am new to bash. I will kindly ask for help from someone who can help me with this problem. I have created a script that makes a backup. Next step would be to make this script run at some certain timestamp in the future. I know I can do this with crontab. My problem is that the script requires some output from the user in order to run properly. (As you can see it asks for the Path) What I need to do is to make the script to take an argument (the path) so It can be runned like this: backup.sh -path=/tmp/myfoldertobackup From what I just read, it seems I have to use getopts but still this is very confusing to me.  It looks like I also need to set the case when no argument is entered. Please help!  Any advice would be greatly appreciated! Thank you!!!  #!/bin/bash #Simple backup script for onee.newdomain.tk echo - e "Please tell me the path of directory you'd like to backup?" read directory cd $directory mkdir backup #mkdir "backup_$(date +'%Y_%m_%d__%H_%M_%S')" SOURCEDIR=$directory tar -czvf public.tgz public_html mysqldump -u onee -pjFztm3s72anA oneex > onee.mysqlbackup.sql mv public.tgz $directory/backup/ mv onee.mysqlbackup.sql $directory/backup/ mv backup backup.`date +"%d-%m-%Y"` echo "===============================" echo "Done!" echo "==============================="

Say, I have a script that gets called with this line: ./myscript -vfd ./foo/bar/someFile -o /fizz/someOtherFile  or this one: ./myscript -v -f -d -o /fizz/someOtherFile ./foo/bar/someFile   What's the accepted way of parsing this such that in each case (or some combination of the two) $v, $f, and  $d will all be set to true and $outFile will be equal to /fizz/someOtherFile?


I wrote a batch file to run multiple batch files which run a java program separately. I am wondering if I need to pass an argument to the java program when I run it, how do I pass the argument when I start the station batch files? The main batch file looks like this:  @ECHO OFF set CLASSPATH=. ECHO open Server   start Server.bat ECHO open station1  start station1.bat ECHO open station2   start station2.bat ECHO open station3   start station3.bat ECHO open station4  start station4.bat   The station batch file looks like this:  @ECHO OFF set CLASSPATH=. java ClientStation  arg1  arg2   arg3 pause

I'd like to find a Windows batch counterpart to Bash's $@ that holds a list of all arguments passed into a script.   Or I have to bother with shift?


I am thoroughly confused as to how exactly radial, tangential, and linear accelerations of points on a rotating wheel relate to each other. Every time I think I know what they mean individually, I find a source that tells me that no, that is wrong. I was actually writing down in this post what I think is correct, only to realize that I was writing the same thing for two obviously different concepts.  First, is radial acceleration the same as centripetal and tangential the same as linear?  Second, how do these different accelerations relate to each other on a spinning disk? I was reading through my textbook, and I think I understand angular velocity perfectly in this context. However, I do not understand, for example:     If a disk rotates at a constant angular velocity, why does a point on the rim have radial but not tangential acceleration? Mathematically, this makes sense (since $a=r\alpha$, so if $\alpha=0$, then so must $a$), but not conceptually. Does it have radial/centripetal acceleration simply because it is still exhibiting circular motion? Would the linear acceleration change––is there any linear acceleration?   Basically, I do not really understand how radial, tangential, and linear accelerations relate to each other? I have just a big salad of greek letters in my head.

To my knowledge there are three types of acceleration when a body (e.g. a rod) is moving in a circle about an axis. These are:   Angular acceleration : this is the rate of change of angular velocity. Tangential acceleration : this is the linear acceleration of the system in a tangential direction to the circle and equals the radius times the angular acceleration. Radial/centripetal acceleration : this is the linear acceleration of the system that is directed inwards towards the center of the circle.   I also think there are two types of velocity:   Linear velocity: this is its velocity in the tangential direction and is constantly changing Angular velocity or angular frequency: this is the rate of change of angle.   Is the above correct? And have I missed anything?


Just as an example:   If I have 130 reputation and provide 50 as a bounty for a question, do I lose any of my existing privileges (due to the 130-50 reputation)?

For example, if your reputation starts above 50 and then falls below 50, do you lose the ability to leave comments? Or, are privileges forever, once earned?


While logged into Windows, I deleted a disk partition which was containing Ubuntu. When I restarted my pc, it is showing 'grub rescue' command prompt.   How to boot windows now?    I no longer require Ubuntu.  I have Ubuntu live CD   When I tried the following commend:  sudo apt-get install lilo   the following error is shown:  Err http://archive.ubuntu.com/ubuntu/ natty/main lilo i386 1:22.8-10ubuntu1   404  Not Found [IP: 91.189.92.156 80] Failed to fetch http://archive.ubuntu.com/ubuntu/pool/main/l/lilo/lilo_22.8-10ubuntu1_i386.deb  404  Not Found [IP: 91.189.92.156 80] E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?

I have absolutely no experience with Linux, and I desperately need to get my computer back up and running again with Windows.  How do I remove Ubuntu and reinstall Windows?    Editor's note: many of the answers are about removing Ubuntu from dual-boot but keeping Windows (which is a bit complicated), while other answers are about removing Ubuntu from single-boot (which is easy: basically just format the disk while installing Windows). The question as written is ambiguous between dual-boot or single-boot.


After some errors with using the actual windows installer,I have gone to using the regular one.However,I'm not sure how exactly to install it.The name is:  forge-1.7.10-10.13.0.1180-installer-win .So,does anyone know how to install this?

I'm having a really, really hard time figuring out how to install mods on Minecraft. I've looked everywhere I can think of for help but the information is almost always outdated or unhelpful.  I've seen on several sites about the use of something called Forge. The Mod I want to use requires 1.6.4 Forge and I have both Forge and the Mod folders sitting in my downloads folder.  I haven't installed any kind of mods for any game prior to this and I have little clue to the technical side of Minecraft, so please keep this in mind when you give me an answer please!  Things that might help you figure out how to help me:   I want to play this mod  and am using the 1.6.4 Forge given on a link that website gives


I use the package :  \usepackage[style=authoryear, language=french]{biblatex}   I have followed the instructions given for this precedent question  to add the terms Vol. and N° in the references section.  But once I have used :  `  \DeclareFieldFormat[article]{volume}{\bibstring{volume}\addnbspace #1} \DeclareFieldFormat[article]{number}{\bibstring{number}\addnbspace #1}  I get for instance :      Howard, Sue ; John Dryden et Bruce Johnson (sept. 1999), « Childhood Resilience: review and critique of literature », in : Oxford Review of Education, t. 25, no 3   How to transform the "t." into "Vol." without having to switch into the english version of authoryear ?

Suppose I've just made the switch to . I have chosen one of the built-in styles (numeric, alphabetic, authoryear, authortitle, verbose) or of the custom styles available at CTAN, and I've figured out how to sort/compress citations. The bibliography and the in-text-citations look approximately like I want, but need to be tweaked. I've taken a look at the biblatex documentation for advice, but it is somewhat daunting. How do I get started? To add some focus, customization in the following areas would come in handy:   Suppressing of specific BibTeX fields (e.g., publisher); Formatting of fields for specific entry types (e.g., titles of articles not inside quotation marks); Formatting of citation postnotes (i.e., getting rid of "p."/"pp."); Spacing and punctuation in the bibliography (e.g., commas instead of periods as unit separators); Order of first names and last names of authors/editors in the bibliography; Order of certain fields in the bibliography (e.g., swapping location and publisher); Language-specific terms (e.g., replacing "References" with "Works Cited").   Finally, assuming that I'll want to use my style adjustments in a multitude of documents: Where do I put the relevant macro stuff?


I'm trying to determine if a particular item in an Array of strings is an integer or not.  I am .split(" ")'ing an infix expression in String form, and then trying to split the resultant array into two arrays; one for integers, one for operators, whilst discarding parentheses, and other miscellaneous items. What would be the best way to accomplish this?   I thought I might be able to find a Integer.isInteger(String arg) method or something, but no such luck.

I normally use the following idiom to check if a String can be converted to an integer.  public boolean isInteger( String input ) {     try {         Integer.parseInt( input );         return true;     }     catch( Exception e ) {         return false;     } }   Is it just me, or does this seem a bit hackish?  What's a better way?    See my answer (with benchmarks, based on the  by ) to see why I've reversed my position and accepted  to this problem.  I think this original code will be used by most people because it's quicker to implement, and more maintainable, but it's orders of magnitude slower when non-integer data is provided.


I am trying to create thread safe singleton class here is my code:  #include<iostream> #include<mutex>  using namespace std; std::mutex mtx;  class MySingleton{ private:     static MySingleton * singletonInstance;     MySingleton();     MySingleton(const MySingleton&);     const MySingleton& operator=(const MySingleton&);     ~MySingleton(); public:     static MySingleton* GetInstance();     void foo(); };  MySingleton::MySingleton(){     std::cout << "Ctor\n"; };  MySingleton::~MySingleton(){     std::cout << "Dtor\n"; };  void MySingleton::foo() {     cout << "Inside Foo" << endl; }  MySingleton* MySingleton::GetInstance(){     //double check     if (singletonInstance == NULL){         std::lock_guard<std::mutex> lock(mtx);         if (singletonInstance == NULL)             singletonInstance = new MySingleton();     }     return singletonInstance; }  int main(void){     MySingleton::GetInstance()->foo(); }   I executed this code in VS2015 and found the below error:  1>Source.obj : error LNK2001: unresolved external symbol "private: static class MySingleton * MySingleton::singletonInstance" (?singletonInstance@MySingleton@@0PAV1@A) 1>E:\CPP\Test\Debug\Singleton.exe : fatal error LNK1120: 1 unresolved externals   I am not sure what is missing in my code,just wanted to call the foo() with the singleton instance. Can any one help to figure out the cause of error?

Very simply put:  I have a class that consists mostly of static public members, so I can group similar functions together that still have to be called from other classes/functions.  Anyway, I have defined two static unsigned char variables in my class public scope, when I try to modify these values in the same class' constructor, I am getting an "unresolved external symbol" error at compilation.  class test  { public:     static unsigned char X;     static unsigned char Y;      ...      test(); };  test::test()  {     X = 1;     Y = 2; }   I'm new to C++ so go easy on me. Why can't I do this?


Recently I came across this problem :     If $a_{0} = 1$ and $a_{n} = a_{[n/2]} + a_{[n/3]} + a_{[n/6]}$ where $[x]$ denotes the greatest integer not exceeding $x$ then show that $$\lim_{n \to \infty}\dfrac{a_{n}}{n} = \frac{12}{\log 432}$$   The recurrence relation is very strange and seems to be multiplicative (has terms like $a_{[n/2]}$) instead of being additive (having terms like $a_{n - 1}$ etc) and I wonder how such a recurrence can be solved. Any suggestions are welcome!

Nice problem:  Let $a_{0}=1$ and $$a_{n}=a_{\left\lfloor n/2\right\rfloor}+a_{\left\lfloor n/3 \right\rfloor}+a_{\left\lfloor n/6\right\rfloor}.$$  Show that  $$\lim_{n\to\infty}\dfrac{a_{n}}{n}=\dfrac{12}{\log{432}},$$  where $\lfloor x \rfloor$ is the largest integer not greater than $x$.  It is said this problem was created by Paul Erdős, and I can't find this problem's solution, does anyone have any nice methods? Thank you.


I have a form with a disabled submit button. Even though the user can't press this button, he can still hit Enter to submit the form. How do I prevent that?

How do you prevent an ENTER key press from submitting a form in a web-based application?


This maybe a silly question, but how do I type this first symbol? I can't seem to find it in any lists. Is it a small delta?

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


Where is Stack Overflow on Area 51?  Usually, when you head to search and type something like EL&U (I wanted to check the stats), it pops up.  But when I search Stack Overflow, nothing comes up.  Why is this?

Recently I found some sites that are a part of the Stack Exchange network but were not proposed. In other words, I'm talking about sites that are not established through Area51, like Super User.  Which sites are these that are part of the Stack Exchange network and have not been proposed / were not established through Area51?


I am trying to develop a web portal using ol5 API where user click on map and then it takes map click event coordinates as centroid of rectangle and create a rectangle of particular height and width.  Here is the to create square  image: new ol.style.RegularShape({         fill: fill,         points: 4,         radius: 30,         angle: Math.PI / 4     })   But I want to create rectangle with center point , height and width. How to achieve this?

I am trying to develop a web portal using ol5 API where user click on map and then it takes map click event coordinates as centroid of rectangle and create a rectangle of particular height and width.  Here is the code to create square  image: new ol.style.RegularShape({         fill: fill,         points: 4,         radius: 30,         angle: Math.PI / 4     })   But I want to create rectangle with center point, height and width. How to achieve this?


So for the play fair case, the number of possible keys is : 26x26 = 676 possible keys  But if we consider the repeated letters, how many unique keys will the play fair have? I mean how will considering the redundant letters affect the number of possible keys?

I was just studying the Playfair cipher and from what I've understood, it is just a slightly better version of a Caesar cipher, in that it isn't actually mono-alphabetic but rather the 'digrams' are mono-alphabetic. I believe that since it offers a larger combination i.e 26*26=676 digrams, it is better than a Caesar Cipher which would give us a maximum of twenty-six keys. So does this mean that the Playfair Cipher have 676 keys including the duplicate or is it larger than that ?


I have a python script that looks something like this:  for item in collection:     print "what up"     #do complicated stuff that takes a long time.   In bash, I run this script by doing the following:  $ python my.py | tee my_file.txt   However, all I see in bash is a blank line until the program finishes. Then, all of the print statements come all at one.  Is this the expected operation of tee? Can I use tee to see the output in real-time?

Is output buffering enabled by default in Python's interpreter for sys.stdout?  If the answer is positive, what are all the ways to disable it?  Suggestions so far:   Use the -u command line switch Wrap sys.stdout in an object that flushes after every write Set PYTHONUNBUFFERED env var sys.stdout = os.fdopen(sys.stdout.fileno(), 'w', 0)   Is there any other way to set some global flag in sys/sys.stdout programmatically during execution?


I was looking at the device administrators of my phone in the settings and saw a device administrator called "screen lock service". It's description is "Activating this administrator will allow the app Google play services to perform the following operations: set password rules". I have looked at my device administrators before and this particular one was never there before. It just appeared out of nowhere. Can anyone tell me what this is and if I should be doing something about it?

Background:  I was looking at the device administrators of my phone in the settings and saw a device administrator called "screen lock service". It's description is "Activating this administrator will allow the app Google play services to perform the following operations: set password rules".  A previously unsettled question is found . I searched the net for the apk file of the application but could not find one. So as per suggestions, I ran adb shell dumpsys package  resolvers | sed -n /android.app.action.DEVICE_ADMIN_ENABLED/,/:/p  The output for the above code was:   android.app.action.DEVICE_ADMIN_ENABLED:     438a74 com.motorola.demo/.admin.DemoModeAdminReceiver     2acd3de com.google.android.gms/.auth.managed.admin.DeviceAdminReceiver     36b5d24 ch.deletescape.lawnchair.ci/ch.deletescape.lawnchair.gestures.handlers.SleepMethodDeviceAdmin$SleepDeviceAdmin     42aae3e com.google.android.gms/.tapandpay.admin.TpDeviceAdminReceiver     8efd08d com.google.android.gms/.kids.account.receiver.ProfileOwnerReceiver     9b4f242 com.google.android.gms/.mdm.receivers.MdmDeviceAdminReceiver     a9980b6 com.oasisfeng.greenify/.DeviceAdmin     b5771b7 com.google.android.gm/com.android.email.SecurityPolicy$PolicyAdmin   com.motorola.internal.intent.action.INETCONDITION_REPORT:  The data for the code is quite unsettling for the fact that none seem to correspond to screen lock service.  For reference, I am using Moto G5 Plus (not rooted, stock build with no customizations) Also note that, I own another same device which is rooted and runs Pixel-Experience (Android 10 latest build) and unfortunately it does not have the Screen Lock Service. An insight/breakdown for this application is helpful.


I have the following question:      Give a combinatorial proof that if $0\le a,k\le n$ are integer than $$\sum_{b=0}^k\binom{a}{b}\binom{n-a}{k-b}=\binom{n}{k}.$$   I'm new to the notion of a combinatorial proof, I understand that it's a proof by counting, i.e. showing the two expressions are in fact counting the same objects, instead of an algebraic proof.  Now, I know $\binom{n}{k}$ represents the ways of choosing k objects from n objects. I know this may be obvious to some, but can someone lead me to the correct way of thinking for interpreting the left-hand side?  Am I right in saying it is something like the sum of all the different (k-b)-subsets from a collection of (n-a) objects, or am I completely wrong?   Thanks for your help!

I'm really iffy on combinatorial proofs in general and now that there is a sum, it's just confused me even more. Can someone try and walk me through this proof?  $$ \binom{m + n}{r} = \sum_{k=0}^r \binom{m}{k}\binom{n}{r - k} $$


I'm working on a function that should be dealing with differential equations and for some specific inputs it can take so long for the function to execute, it's probably because I've used Sympy's dsolve inside it. What I'd like to do now is make it report a time out incase the process takes any longer than 12 seconds or any number, how should I do that?

I'm calling a function in Python which I know may stall and force me to restart the script.   How do I call the function or what do I wrap it in so that if it takes longer than 5 seconds the script cancels it and does something else?


Defining multivariable differentiation is just linear algebra. However, defining integration is complicated measure theory. Why are these efforts so different?

If a function is a combination of other functions whose derivatives are known via composition, addition, etc., the derivative can be calculated using the chain rule and the like. But even the product of integrals can't be expressed in general in terms of the integral of the products, and forget about composition! Why is this?


I read   I understand why choosing smallest gini index, but how do I come up with different candidate splits in the first place? How does R come up with the splits? Take the iris data as an instance:  plot(iris$Sepal.Length, col=iris$Species, pch=20)     How do I determine where I want to draw the horizontal line to separate each class? I can draw infinitely amount of lines and then compare their gini index, but practically, it will not work.

I have two questions related to decision trees:   If we have a continuous attribute, how do we choose the splitting value?  Example: Age=(20,29,50,40....) Imagine that we have a continuous attribute $f$ that have values in $R$. How can I  write an algorithm that finds the split point $v$, in order that when we split $f$ by $v$, we have a minimum gain for $f>v$?


Problem Statement     Given finite $X \neq \emptyset$ together with an associative binary operation, if left-cancellation and right-cancellation laws hold, is $X$ a group?   Attempt  We know that for all $x, y, z \in X$, left-cancellation $$xy = xz \implies y = z$$ holds.  Thus, the function $L_{x}:X \to X$ defined by $$L_{x}(w)=xw$$ is injective.  Since $X$ is finite, $L_{x}$ must also be surjective.  This means that there exists an element $e$ of $X$ such that $L_{x}(e)=x$, i.e. $x=xe$.  First, we want to show that $e$ is in fact a two-sided identity for $X$.  So let $v$ be an arbitrary element of $X$, and consider $xv=(xe)v=x(ev)$ (by associativity).  Thus, by left-cancellation, $v=ev$ for all $v$, i.e. $e$ is a left identity.  Now consider $vv=v(ev)=(ve)v$ (again, by associativity).  By right-cancellation, we conclude that $v=ve$, i.e. $e$ is a right identity.  Next, we need to show the existence of inverses.  From before, for every $w \in X$, the function $x \mapsto wx$ is surjective, so there is an element, say $w_R$, such that $w{w_R} = e$.  Similarly, there is an element $w_L$ such that ${w_L}w = e$.  Since $$w_L = {w_L}e = {w_L}(w{w_R}) = ({w_L}w){w_R} = e{w_R} = w_R,$$ we conclude that $w_L = w_R$ is a two-sided inverse for $w$.  Caveat  But wait!  I have not yet established closure of the binary operation!  Additionally, I also need to show that the result in this problem may be false if $X$ is infinite.  Any hints you can provide will be gladly appreciated!  Question     Is my attempt above acceptable for the given problem at hand?  Or would there be a more direct approach?

Let $G$ be a finite, nonempty set with an operation $*$ such that   $G$ is closed under $*$ and $*$ is associative Given $a,b,c \in G$ with $a*b=a*c$, then $b=c$. Given $a,b,c \in G$ with $b*a=c*a$, then $b=c$.   I want to prove that $G$ is a group, but I don't know how to show that there exists an identity $e\in  G$ such that $e*x=x$ and $x*e=x$ $\forall x \in G$. I also don't know how to show that $\forall$ x $\in G$ there exists a $y \in G$ such that $y*x=e$ and $x*y=e$. How do I do this?


After completing download 100% from google play store app wont install but after 3 to 4 hour it install itself. What could be the problem??

I have a problem with installing apps from Google Play onto my Samsung Galaxy S Plus phone.  It has Android 2.3.6. Yesterday I tried to download some apps. When I clicked 'Install', the app began to download but when it got to 100% it just disappeared and silently failed to install on my phone :\  I don't have an SD card and up to now I saved all my apps on the phone and had no problems like this. It seems to be some settings problem, but I don't know what to do. any ideas?!


When I try to connect to bluetooth nothing happens it just stops pairing after a few seconds

With Ubuntu 16.04 I've been attempting to pair by Apple airpods as a headset. They come up as headphones. They work fine as headphones, but I would like the microphone to be available


We are Australians planning a trip to Cuba. We can now fly direct from LA but are worried that we might not be allowed to board, even with a visa. Dies anyone know the current situation?

I may be visiting the US soon for both work (conference) and leisure (sight-seeing) but was wondering whether it is possible to pay a visit to Cuba, as I see that direct commercial flights have been restarted. From what I can tell, it is still not permitted for US citizens to travel to Cuba as tourists (from the ).  What is the legal status of European citizens - would it be permitted for me to travel as a tourist from, say, Florida to Cuba on a commercial flight? Would this cause problems for me on my return to the US?  I understand that the question has been asked before () but the situation has changed and I believe it warrants asking again.


I installed ubuntu alongside windows 8.1 and i installed correctly by creating partitions and the laptop finally says restart to use ubuntu but when i do , it agains diplays a gnu grub version showing : -try ubuntu without installing -install ubuntu -oem install -check disc for defects.  also i have no idea where my windows has gone.

I installed Windows on my computer, followed by an installation of Ubuntu. However, now I'm unable to boot into my Windows install.  What can I do to fix this?


I can't figure it out why this is happening. I want to animate a logo frame by frame using Photoshop CS5 and everytime i change something in a frame, it changes all frames before until the moment i created a layer/shape. In result, all frames turn to be the same.  I'm thinking to use 4 layers and I would animate "interior" layer first and  "splashes" in the end.  My layers:  4 - splashes (to edit)  3 - interior (to edit)  2 - vector smart object mask (lock)  1 - background (lock)  Should I create a new layer for each new frame to resolve this problem?

I am trying to create an animated gif where text drops down and smashes into the background and cracks it. Whenever I try and transform it though, the transformation is applied to all frames. How do I prevent this? I'm using Adobe Photoshop CS6 (64-bit)


There are some outdated plugins. But those are not seem to be useful and not actually working.  There are 2000 post titles and I want to bulk edit/replace specific word from them. How can I do this by using mysql command?  Like this : Changing Sloppy to Ronn in 2000 wordpress post titles at once. How can I do that?

What MySQL query will do a text search and replace in one particular field in a table?  I.e. search for foo and replace with bar so a record with a field with the value hello foo becomes hello bar.


If I'm querying more than 1 post type, is it possible to ensure that I will always get at least 1 of each type?  $args = array(     'post_type' => array( 'post', 'project' ),     'posts_per_page' => 3,     'ignore_sticky_posts' => true, );  $recent_posts = new WP_Query( $args );   In this example, I'd like to ensure that I always have at least 1 post in the 3 posts that are returned.  I dislike how sticky posts behave as it ends up returning more than the 3 items requested and will impact other parts of my site.

I have three custom post type:    books magazine videos   Now i want to limit the number of post for custom post type, for example:   books => 3 post magazine => 2 post videos => 1 post   I used a query post like this:  query_posts( array(     'post_type' => array(     'books',     'magazine',     'videos' ), 'paged' => $paged, 'posts_per_page' => 6,  )); $counter = 1; if (have_posts()) :     while (have_posts()) : the_post();   if (($counter == 2) || ($counter == 3) || ($counter == 4)) {         $div = 'alpha';     } elseif(($counter == 6)) {         $div = 'omega';     } else {         $div = '';     }   The problems is i cant limit the numbers by custom post type.  Any idea?  Thank you :)


We are having a problem within our server. After transferring the files to a new dedicated server, within only one or two weeks almost every website under our server is redirecting to a porno scammy sites (to be blunt to adultfinder website). Once you enter the url it will redirect to it and once you enter it once again you are now in the original website.

This is a  about Server Security - Responding to Breach Events (Hacking)   See Also:                  Canonical Version I suspect that one or more of my servers is compromised by a hacker, virus, or other mechanism:   What are my first steps? When I arrive on site should I disconnect the server, preserve "evidence", are there other initial considerations? How do I go about getting services back online? How do I prevent the same thing from happening immediately again? Are there best practices or methodologies for learning from this incident? If I wanted to put a Incident Response Plan together, where would I start? Should this be part of my Disaster Recovery or Business Continuity Planning?   Original Version       2011.01.02 - I'm on my way into work at 9.30 p.m. on a Sunday because our server has been compromised somehow and was resulting in a    attack on our provider. The servers access to the Internet   has been shut down which means over 5-600 of our clients sites are now   down. Now this could be an FTP hack, or some weakness in code   somewhere. I'm not sure till I get there.      How can I track this down quickly? We're in for a whole lot of   litigation if I don't get the server back up ASAP. Any help is   appreciated. We are running Open SUSE 11.0.            2011.01.03 - Thanks to everyone for your help. Luckily I WASN'T the only person responsible for this server, just the nearest. We managed   to resolve this problem, although it may not apply to many others in a   different situation. I'll detail what we did.      We unplugged the server from the net. It was performing (attempting to   perform) a Denial Of Service attack on another server in Indonesia,   and the guilty party was also based there.      We firstly tried to identify where on the server this was coming from,   considering we have over 500 sites on the server, we expected to be   moonlighting for some time. However, with SSH access still, we ran a   command to find all files edited or created in the time the attacks   started. Luckily, the offending file was created over the winter   holidays which meant that not many other files were created on the   server at that time.      We were then able to identify the offending file which was inside the   uploaded images folder within a  website.      After a short cigarette break we concluded that, due to the files   location, it must have been uploaded via a file upload facility that   was inadequetly secured. After some googling, we found that there was   a security vulnerability that allowed files to be uploaded, within the   ZenCart admin panel, for a picture for a record company. (The section   that it never really even used), posting this form just uploaded any   file, it did not check the extension of the file, and didn't even   check to see if the user was logged in.      This meant that any files could be uploaded, including a PHP file for   the attack. We secured the vulnerability with ZenCart on the infected   site, and removed the offending files.      The job was done, and I was home for 2 a.m.            The Moral   - Always apply security patches for ZenCart, or any other CMS system for that matter. As when security updates are released, the whole   world is made aware of the vulnerability.   - Always do backups, and backup your backups.   - Employ or arrange for someone that will be there in times like these. To prevent anyone from relying on a panicy post on Server   Fault.


If $\liminf\, |a_n|=0.$ Does there exists a subsequence of $\{a_n\}$  which has finite sum?  I tried to prove as follows: Since $\liminf\, |a_n|=0,$ then we can find $n_1<n_2<n_3\ldots$ such that $|a_{n_{1}}|<\frac{1}{2},$  $|a_{n_{2}}|<\frac{1}{2^2},\ldots.$ Therefore, \begin{align} \sum_{j=1}^N|a_{n_j}|<\sum_{j=1}^{N}\frac{1}{2^j}<1 \end{align} This implies $\left\{\sum_{j=1}^Na_{n_j}\right\}$ is absolutely convergent, hence convergent. Is there another way to prove?

Let $(a_n)_{n\in\mathbb{N}}$ be a sequence such that lim inf $|a_n|=0$. Prove that there is a subsequence $(a_{n_{k}})_{k\in\mathbb{N}}$ such that $\sum_{k=1}^\infty a_{n_k}$ converges.  I'm thought about showing that you can make a subsequence that is smaller then $1/n^2$. Is this the right strategy ? Any hints ? Should I use the Cauchy criterion ?


I am trying to find an a function that can find the title. I have tried os.stat(file) but it only returns the details on the general tab, and I can't find any other attribute in os.stat that can retrieve the stuff on details. For example my code:  import os os.chdir('C:\\PythonScripts') statinfo = os.stat('01 of CDImage01.mp3') print(statinfo)   I am planning to make a program that can swap the title and the file name.

How can I retrieve mp3 metadata in Python?


I have this:  node ${SUMAN_RUNNABLE} | tee -a run.sh.log EXIT_CODE=$?;   but it looks like the exit code is always 0 because tee is providing the code not the node executable.  Is there a way to capture the exit code from the node executable in such a scenario?

I have two processes foo and bar, connected with a pipe:  $ foo | bar   bar always exits 0; I'm interested in the exit code of foo. Is there any way to get at it?


Am trying to install for dual boot system. OK on one XP computer but on XP laptop I receive following message  -  "unable to boot - please use a kernel appropriate for your CPU.  Not present pae. Don't understand what is meant by pae. Have burnt two DVDs one on each machine, and whilst both work on the PC, both come up with the same message on the laptop. Can anyone please point me in the right direction to correct this error. Thanks, Roy

After burning Ubuntu 12.04 to a CD, I tried booting and got the message:  This kernel requires the following features not present on the CPU: pae  Unable to boot - please use a kernel appropriate for your CPU.   What does this mean?


I'm trying to revive a MacBook Air 2017 that suffered a liquid spill (diet Crystal Light on the keyboard). After a week of drying, open, in an aggressively dehumidified room, it started up and behaved normally for a week or so, but then failed to start up. Now it won't boot at all or respond in any way.   Laptop: 13" MacBook Air MQD32LL/A (1.8GHz Core i5, 8GB) Logic board: 820-00165-A  This question differs from . I am asking whether the described symptoms isolate the problem to the logic board as opposed to other parts, which is not asked or answered there. Repair/replacement of the logic board is relatively expensive, so it would be useful for people in this or similar situations to be able to evaluate the level of certainty that the logic board is the locus of the problem. Although I reviewed numerous related questions including the above, I haven't seen any thorough treatments of this question.  More details   I don't see any sign of liquid remnants or corrosion on any internal components, but the moisture detector under the display data cable connector was activated. After the charger hasn't been connected for 10 minutes or so, when connected its diode will flash green for an instant, once. Other than that, the diode will not light, even dimly. Tested with two known-good Apple Magsafe chargers; same results. But with the battery out and the I/O ribbon disconnected, when I connect the charger its diode lights up green (or occasionally amber) for a minute or so then fades slowly to dark. (Interesting: In order to repeat this sequence and get the diode to light again, it seems the charger has to be connected to a different, known-good computer, just for a second, as if it needs to reset itself.) SMC reset: No response and no change. Jumping the power pads: No response, even with keyboard/trackpad ribbon disconnected. Tested with battery and charger, battery only, and charger only; also with charger only and I/O ribbon disconnected. Tested with a second known-good battery: No change Replaced top case: No change Replaced I/O board and I/O ribbon connector: No change   I don't know whether the Crystal Light got to the logic board or if this problem could be caused a fault in a cheaper part, say the I/O board — and maybe I got a second faulty I/O board.  The question, more precisely: Do the symptoms described indicate that the problem is almost certainly in the logic board, or almost certainly somewhere else, or is it inconclusive?

Sadly, yesterday I've spilled some water on my MacBook Pro (El Capitan). Before you yell at me - it was closed, turned off and it wasn't a lot of water, the laptop was wet only on the top and under - not inside.  Today I've turned him on. At first battery wasn't recharging for some reason, but SMC reset fixed the problem.  At the first booting speaker was like talking to me, hard to explain but it was weird. Also only right speaker was "talking", despite the fact that only left side of the laptop was watered. Then there was no sound at all, not from the speakers, nor from the headphones. Also microphone's not working. USB ports are okay. The water was spilled from the left side of the laptop. I know this is hardware issue, and something's broken, but I want to be 100% sure. No it's not muted. I've also tried NVRAM reset a few times, but it doesn't fix the problem :(  There might be one factor, before spilling, my laptop "died" for the first time (battery energy ran off), but I doubt it's the case. (but hey, every info matters, right?)  It wouldn't be weird for me, if only left speaker wouldn't work, but built-in microphone not working is kinda weird in this case, isn't it?  I just want to ask you guys, what else can I check, before I'll be 100% sure it's dead inside?  I've plugged in external microphone - it's not working too.


I was playing with an old point and shoot camera and I made this close-up photo of a pepper:     I took many photos and it seems I can’t get a sharp image across the whole object. Can I make this better with settings? Is 8 megapixels not enough?  Or is my point-and-shoot camera really that bad that the only chance of improving this image is with a new camera body and a better lens (macro lens)? If so, what cheaper options do I have (beginner lens + extension tube)?  My settings: f7.1  1/4 sec  ISO-80  Camera model: Canon PowerShot S5 IS Focal length: 6mm  I took another photo:   The front side seems sharp enough but how can I make the left side that is further away from the camera just as sharp? f/8 1/5 sec ISO-80

I want to make a full focus on the body, for example: I need to have a clear focus on the each balls in the photo. I used just single point focus.    In this picture I used:   shutter speed: 8 aperture: F/4 ISO: 200 2 flashes, one in the right and one on the top of project camera: nikon d300s lens : 105mm micro 2.8   Thanks


$\mathbb{R}^{n}_{1}$ is  $\mathbb{R}^{n}$ with norm $\lVert (x_{1},...,x_{n}) \rVert_{1}= |x_{1}|+...+|x_{n}|$. $\mathbb{R}^{n}_{\infty}$ is  $\mathbb{R}^{n}$ with norm $\lVert (x_{1},...,x_{n}) \rVert_{\infty} = \max\{|x_{1}|,...,|x_{n}|\}$. I know the closed unit ball in the spaces have different shapes when $n>2$. However, I can't use the fact to give a proof.

Could you please give me a hint to prove that $\mathbb{R}^n$ with the 1-norm $\lvert x\rvert_1=\lvert x_1\rvert+\cdots+\lvert x_n\rvert$ is not isometric to $\mathbb{R}^n$ with the infinity-norm $\lvert x\rvert_\infty = \max_{i=1,\ldots,n}(\lvert x_i\rvert)$ for $n\gt2$.  I do not see how the critical case $n=2$ enters the picture.  Thank you!


How do I export map information display styles from ArcGIS Desktop to QGIS?   I tried exporting MXD to QGS (using mxd2qgs) - but the styles were not saved;Also, when I try to export styles from arcgis to SLD format (using ArcGIS_SLD_Converter) and finally got:     "Index outside the range."   The index should be a positive number, and its size should not exceed the size of the collection Parameter name: index in System.collections.ArrayList.get.item (lnt32 index) in ArcGis_SLD_Converter.Output_SLD.WriteToSLD()"

Is there a way to convert a symbol style set for ArcGIS for use in QGIS?    There are symbols used in Incident Command I would like to use in QGIS, but can only find a style set for use in ArcGIS.  The style set I have is saved as a .style file.


Can anyone explain when and how to use << operator for input redirection? I've googled enough but couldn't find.

I often see tutorials online that connect various commands with different symbols. For example:  command1 |  command2 command1 &  command2 command1 || command2     command1 && command2   Others seem to be connecting commands to files:  command1  > file1 command1  >> file1   What are these things? What are they called? What do they do? Are there more of them?    .


I'm confused with the objects and constructor in Java. I query from a SQLiteDatabase but I couldn't get the correct object/answer. I know my codes look messy and I need to clean it up but I don't know where to start...  public static class QObject {          public String word;         public String definition;          public QObject(String word, String definition) {             this.word = word;             this.definition = definition;         }          public QObject getAnswer(String message) {              QObject quizObject = null;             String query = "select * from " + TABLE_NAME + " where " + COL_WORD + " = '" + message + "'";              Cursor cursor = this.getDbConnection().rawQuery(query, null);                 if(cursor.moveToFirst()) {                     do {                         String myword = cursor.getString(cursor.getColumnIndexOrThrow(COL_WORD));                         String mydefinition = cursor.getString(cursor.getColumnIndexOrThrow(COL_DEFINITION));                         quizObject = new QObject(word, definition);                     } while (cursor.moveToNext());                 }                 cursor.close();                 return quizObject;         }          private SQLiteDatabase getDbConnection() {             return dbHelper.getReadableDatabase();         }     } }      public void searchName(View view) {         String word = null;         String definition = null;         DatabaseTable db = new DatabaseTable(this);          DatabaseBackend dbBackend = new DatabaseBackend(MainActivity.this);         DatabaseObject dbo = new DatabaseObject(this);         DatabaseB.QObject quizobject = new DatabaseB.QObject(word, definition);         DatabaseB.QObject allQuizQuestions = quizobject.getAnswer(message);          String answer = allQuizQuestions.definition;          TextView textView = findViewById(R.id.textView2);         textView.setText(answer);      }   The error message is null object reference:  Caused by: java.lang.reflect.InvocationTargetException at java.lang.reflect.Method.invoke(Native Method) at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288) ... Caused by: java.lang.NullPointerException: Attempt to read from field 'java.lang.String com.justkitting.orion.databasetest.MainActivity$DatabaseB$QObject.definition' on a null object reference at com.justkitting.orion.databasetest.MainActivity.searchName(MainActivity.java:139) at java.lang.reflect.Method.invoke(Native Method) ...   Many many thanks.

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


Hey guys I recently installed ubunt 10.04 and I want to upgrade to 11.04 (I had a really small flash drive and I could only get 10.04 so I wanted to keep upgrading) But I keep getting unable to fetch now I'm new to using ubuntu so if you guys could help it'd be great  Error message :   W:Failed to fetch extras.ubuntu.com/ubuntu/dists/maverick/main/source/Sources.gz  404  Not Found W:Failed to fetch extras.ubuntu.com/ubuntu/dists/maverick/main/binary-i386/Packages.gz  404  Not Found W:Failed to fetch security.ubuntu.com/ubuntu/dists/maverick-security/universe/source/Sources.gz  404  Not Found [IP: 91.189.88.149 80] W:Failed to fetch security.ubuntu.com/ubuntu/dists/maverick-security/multiverse/source/Sources.gz  404  Not Found [IP: 91.189.88.149 80] W:Failed to fetch security.ubuntu.com/ubuntu/dists/maverick-security/universe/binary-i386/Packages.gz  404  Not Found [IP: 91.189.88.149 80] W:Failed to fetch security.ubuntu.com/ubuntu/dists/maverick-security/multiverse/binary-i386/Packages.gz  404  Not Found [IP: 91.189.88.149 80] W:Failed to fetch security.ubuntu.com/ubuntu/dists/maverick-security/main/source/Sources.gz  404  Not Found [IP: 91.189.88.149 80] W:Failed to fetch security.ubuntu.com/ubuntu/dists/maverick-security/restricted/source/Sources.gz  404  Not Found [IP: 91.189.88.149 80] W:Failed to fetch security.ubuntu.com/ubuntu/dists/maverick-security/main/binary-i386/Packages.gz  404  Not Found [IP: 91.189.88.149 80] W:Failed to fetch security.ubuntu.com/ubuntu/dists/maverick-security/restricted/binary-i386/Packages.gz  404  Not Found [IP: 91.189.88.149 80] W:Failed to fetch us.archive.ubuntu.com/ubuntu/dists/maverick/main/source/Sources.gz  404  Not Found [IP: 91.189.91.26 80] W:Failed to fetch us.archive.ubuntu.com/ubuntu/dists/maverick/restricted/source/Sources.gz  404  Not Found [IP: 91.189.91.26 80] W:Failed to fetch us.archive.ubuntu.com/ubuntu/dists/maverick/universe/source/Sources.gz  404  Not Found [IP: 91.189.91.26 80] W:Failed to fetch us.archive.ubuntu.com/ubuntu/dists/maverick/multiverse/source/Sources.gz  404  Not Found [IP: 91.189.91.26 80] W:Failed to fetch us.archive.ubuntu.com/ubuntu/dists/maverick/main/binary-i386/Packages.gz  404  Not Found [IP: 91.189.91.26 80] W:Failed to fetch us.archive.ubuntu.com/ubuntu/dists/maverick/restricted/binary-i386/Packages.gz  404  Not Found [IP: 91.189.91.26 80] W:Failed to fetch us.archive.ubuntu.com/ubuntu/dists/maverick/universe/binary-i386/Packages.gz  404  Not Found [IP: 91.189.91.26 80] W:Failed to fetch us.archive.ubuntu.com/ubuntu/dists/maverick/multiverse/binary-i386/Packages.gz  404  Not Found [IP: 91.189.91.26 80] W:Failed to fetch us.archive.ubuntu.com/ubuntu/dists/maverick-updates/main/source/Sources.gz  404  Not Found [IP: 91.189.91.26 80] W:Failed to fetch us.archive.ubuntu.com/ubuntu/dists/maverick-updates/restricted/source/Sources.gz  404  Not Found [IP: 91.189.91.26 80] W:Failed to fetch us.archive.ubuntu.com/ubuntu/dists/maverick-updates/universe/source/Sources.gz  404  Not Found [IP: 91.189.91.26 80] W:Failed to fetch us.archive.ubuntu.com/ubuntu/dists/maverick-updates/multiverse/source/Sources.gz  404  Not Found [IP: 91.189.91.26 80] W:Failed to fetch us.archive.ubuntu.com/ubuntu/dists/maverick-updates/main/binary-i386/Packages.gz  404  Not Found [IP: 91.189.91.26 80] W:Failed to fetch us.archive.ubuntu.com/ubuntu/dists/maverick-updates/restricted/binary-i386/Packages.gz  404  Not Found [IP: 91.189.91.26 80] W:Failed to fetch us.archive.ubuntu.com/ubuntu/dists/maverick-updates/universe/binary-i386/Packages.gz  404  Not Found [IP: 91.189.91.26 80] W:Failed to fetch us.archive.ubuntu.com/ubuntu/dists/maverick-updates/multiverse/binary-i386/Packages.gz  404  Not Found [IP: 91.189.91.26 80] E:Some index files failed to download, they have been ignored, or old ones used instead.   Thank you guys also if you guys could make the instructions to fix this really clear because I'm an idiot it'd be appreciated thanks <3

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


when I added Firestore cloud dependency, my app crashes when the user logs out     kotlin.KotlinNullPointerException             at com.example.proghelp.ProfileActivity$read_write_fire$2.onEvent(ProfileActivity.kt:93)             at com.example.proghelp.ProfileActivity$read_write_fire$2.onEvent(ProfileActivity.kt:35)             at com.google.firebase.firestore.DocumentReference.zza(Unknown Source)             at com.google.firebase.firestore.zzd.onEvent(Unknown Source)             at com.google.android.gms.internal.firebase-firestore.zzkp.zza(Unknown Source)             at com.google.android.gms.internal.firebase-firestore.zzkq.run(Unknown Source)             at android.os.Handler.handleCallback(Handler.java:605)             at android.os.Handler.dispatchMessage(Handler.java:92)             at android.os.Looper.loop(Looper.java:137)             at android.app.ActivityThread.main(ActivityThread.java:4517)             at java.lang.reflect.Method.invokeNative(Native Method)             at java.lang.reflect.Method.invoke(Method.java:511)             at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:993)             at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:760)             at dalvik.system.NativeStart.main(Native Method)   my firebase dependencies    implementation 'com.google.firebase:firebase-core:15.0.0'     implementation 'com.google.firebase:firebase-storage:15.0.0'     implementation 'com.google.firebase:firebase-database:15.0.0'     implementation 'com.google.firebase:firebase-auth:15.0.0'     implementation 'com.google.android.gms:play-services-auth:15.0.0'     implementation 'com.firebaseui:firebase-ui-database:3.1.3'     implementation 'com.firebaseui:firebase-ui-storage:3.2.1'     implementation 'com.google.firebase:firebase-analytics:15.0.0'     implementation 'com.google.firebase:firebase-firestore:15.0.0'     implementation 'com.android.support:multidex:1.0.3'   my log is in tis code:    var db = FirebaseFirestore.getInstance();        val notebookRef3 = db.collection(currentuser.uid)   notebookRef3.document("name").addSnapshotListener { querySnapshot, e ->             var note = querySnapshot!!.toObject(Note2::class.java)            var name = note!!.username             iduserprofile.text = name         }   it says the log is here      var note = querySnapshot!!.toObject(Note2::class.java)


How can I move all files and folders from one directory to another via mv command?

How do I move all files in a directory (including the hidden ones) to another directory?  For example, if I have a folder "Foo" with the files ".hidden" and "notHidden" inside, how do I move both files to a directory named "Bar"?  The following does not work, as the ".hidden" file stays in "Foo".  mv Foo/* Bar/   Try it yourself.  mkdir Foo mkdir Bar touch Foo/.hidden touch Foo/notHidden mv Foo/* Bar/


I'd like to read the content of the /sys/fs/cgroup/ files (eg. cpuacct.usage) from Java. I've already implemented the reading algorithm based on  answer. The issue is that the cgroup files have 0 length by default. Each of the algorithms listed in the linked answer determines the size of the file before start to read from it, and because the file.length() returns 0, it will attempt to read 0 bytes from the file.  Here is the reading algorithm:  private String readFile(File file) {     DataInputStream stream = null;     String content = "";      try {         stream = new DataInputStream(new BufferedInputStream(new FileInputStream(file)));         final byte[] data = new byte[(int) file.length()]; // new byte[1024] throws exception          stream.readFully(data);         content = new String(data);     } catch (IOException e) {         e.printStackTrace();     } finally {         if (stream != null) {             try {                 stream.close();             } catch (IOException e) {                 e.printStackTrace();             }         }     }     return content; }

If you have a java.io.InputStream object, how should you process that object and produce a String?    Suppose I have an InputStream that contains text data, and I want to convert it to a String, so for example I can write that to a log file.  What is the easiest way to take the InputStream and convert it to a String?  public String convertStreamToString(InputStream is) {     // ??? }


I need to remove a single closed parentheses from a string to fix an edge case in a simpler regex problem.   I need to remove text from within parentheses, but the solution I am currently using doesn't handle an extra single closed parentheses well. Should I use a different approach or can I add an extra step to handle this case?   Below is an example where all answers should be brother & I highlighted the line that it fails on below  cleaner = function(x){   x = tolower(x)   ## if terms are in brackets - assume this is an alternative and remove   x = stringr::str_remove_all(x, "\\(.*\\)")   ## if terms are seperated by semi-colons or commas, take the first, assume others are alternatives and remove   x = gsub("^(.*?)(,|;).*", "\\1", x)   ## remove whitespace   x = stringi::stri_replace_all_charclass(x, "\\p{WHITE_SPACE}", "")   x }  cleaner("brother(bro)") cleaner("brother;bro") cleaner("bro   ther") cleaner("(bro)brother   ;bro") cleaner("(bro)brother   ;bro)") ## this fails cleaner("(bro)brother   ;(bro") # this doesnt  stringr::str_remove_all("(bro)brother   ;bro)", "\\(.*\\)")   Thanks,   Sam

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


I have this script which gives me number results like "4236.13741375". How can I get an output with a price format? Ex. "4,236.14" instead of "4236.13741375". <script type='text/javascript' > function startCalc(){       interval = setInterval("calc()",1); } function calc(){  // ITEM 1 START  d_r1_qte = document.autoSumForm?.d_r1_qte?.value ?? 0; d_r1_unitprice = document.autoSumForm?.d_r1_unitprice?.value ?? 0; d_r1_price = d_r1_qte * d_r1_unitprice; document.autoSumForm.d_r1_price.value =  d_r1_price; // ITEM 1 END  // INVOICE FOOTER START  d_rtotal = d_r1_price;  d_rtotaltx = ((d_rtotal/100)*15)+d_rtotal;  d_fadmin = (d_rtotaltx/100)*3; document.autoSumForm.d_fadmin.value = d_fadmin; d_stotal = d_fadmin + d_rtotal; document.autoSumForm.d_stotal.value = d_stotal; d_tps = (d_stotal/100)*5; document.autoSumForm.d_tps.value = d_tps; d_tvq = (d_stotal/100)*9.975; document.autoSumForm.d_tvq.value = d_tvq; d_total = d_stotal + d_tps + d_tvq; document.autoSumForm.d_total.value =  d_total; // INVOICE FOOTER END }

I would like to format a price in JavaScript. I'd like a function which takes a float as an argument and returns a string formatted like this: "$ 2,500.00"  What's the best way to do this?


My scale transform is in orange color bar.If i apply the scale and save the project also,when i reopen it the scale is not applied and the orange color continues in the scale bar.I couldnt figure it out what mistake i have done here.So please help me to come out from this issue.

I have downloaded a free model for my current project and spotted those different colors on Scale, Rotation, Location, and other properties. What do these different colors signify? What is the meaning of various possible color overlays on UI properties buttons? The very same model after Ctrl + C Ctrl + V to my project file disappeared after a while.


When I run apt-get --yes upgrade in a script it sometimes stops and prompts for input.  Today in 14.04 LTS it is prompting for what to do for grub/menu.lst.   I don't know what could be asked for in a future upgrade.  I tried running this with a newline piped in.  I also tried just a carriage return.  neither worked (seems like the input was lost). I did not find a suitable option in apt-get such as --no-prompts.  I tried the answer  but it still gives me a menu prompt asking what config choice I want.  Any idea how to bypass this prompt?

When running apt-get -y install <packages ...> on Ubuntu 10.04 I would like apt-get (or aptitude if that makes it easier) to not prompt me when installing additional dependencies (behavior of -y as I understand it) and but not prompt me about overwriting configuration files, instead assume to keep the existing ones always (which is usually the default). Unfortunately --trivial-only seems to be the inverse of -y and not affect the prompt that is shown, according to the man page.  In particular packages auch as samba, nullmailer, localepurge and lighttpd have forced me to interact with the terminal, even though the whole procedure was scripted and meant to be non-interactive.


In the example given in §14.4.1 "Accelerated C++, A. Koenig and B. E. Moo" I have problems if I implement the template specialization like it is presented in the book.  The minimum working example (top down) is:  g++ str.cpp main.cpp     main.cpp:  #include "str.hpp"  int main(int argc, char** argv)  {      Str n;                //def      return 0;  }     str.hpp:  #ifndef GUARD_str_h #define GUARD_str_h  #include <vector>  #include "ptr.hpp"  class Str {     public:         Str(): data(new std::vector<char>) { }     private:         Ptr< std::vector<char> > data; }; #endif     str.cpp:  #include "str.hpp"     ptr.hpp:  #ifndef GUARD_ptr_h #define GUARD_ptr_h  #include <vector>   template<class T> T* clone(const T* tp); template<> std::vector<char>* clone(const  std::vector<char>* vp);  template <class T> class Ptr {     public:         Ptr(): refptr(new size_t(1)), p(0) { }         Ptr(T* t): refptr(new size_t(1)), p(t) { }         ~Ptr();     private:         T* p;         size_t* refptr; };  #include "ptr.cpp" #endif     ptr.cpp:  template<class T> Ptr<T>::~Ptr() {     if (--*refptr == 0) {         delete refptr;         delete p;     } }  template<class T> T* clone(const T* tp) {     return tp->clone(); }  template<> std::vector<char>* clone(const std::vector<char>* vp) {     return new std::vector<char>(*vp); }   The problem is the last template specialization   template<> std::vector<char>*   It gives an   multiple definition of 'std::vector<char...>   error. It only works with   template<> inline std::vector<char>*   1) I do not fully understand why I need "inline".  2) Is this an error in the book? I tried to put this template specialization in the ptr.hpp file. Again, it only works with "inline".  Thanks to all who can put some light on this issue.

Quote from :     The only portable way of using templates at the moment is to implement them in header files by using inline functions.   Why is this?  (Clarification: header files are not the only portable solution. But they are the most convenient portable solution.)


I had my phone undergo factory reset because there was some kind of malware and worms but it didn't work so I had it professionally fixed. And when I was going to re-install an app but it's already removed from the play store and I don't want to download from unknown sources. Is there a way to retrieve this? If there's none, what could be a good alternative for Google Play? I'm scared from unknown sources because of what happened to my phone before it was fixed.

I have installed a few Android applications both with the adb install MyApplication.apk command and via a webserver (like an alternative to Android Market).  But where in the Android file system on my phone is the MyApplication.apk file placed? Are applications installed with adb install not placed in the same directory as applications downloaded from the Market?  I found some applications on /system/app but I can't recognize them as some downloaded from Android Market or the one I have installed with adb install.  Where on the system is applications that I have installed located?  My phone is not rooted, and I am running Nexus One with Android 2.2.1.


I have an 80GB PS3 from 2009, and the hard drive is almost full. I recently got a PS4 as well, so I signed up to Playstation Plus but could not download and install any of the free games on my PS3 because there was no room on the HDD. I have an external HDD that is formatted to FAT32 that I can watch TV shows and Movies on through my PS3, but can I move my downloaded games onto the external HDD and install and play them from there. I also have other games that had to be installed, like GTA 5 and the Assassin's Creed heritage collection which take up heaps of room too.

I have a PS3 Super Slim with 12 GB of flash. I need to expand its storage to install games.  On the net, I found contrasting opinions: I know I need a disk formatted in FAT32, but I don't understand if I can install games on it or if I can only store saves and multimedia on it.  In case I have to install an internal drive, do I need something to place it in? Some type of box?


Similar to my old question. Is there a way I can store what the user inputs into an array so I can call it via stringName[1] or stringName[2]?  I am not well versed in java split.   for example, if I had  System.out.println ("A sentence or your full name please" ); for (int j = 0; j < arrayTwo.length; j++){ array[j]= sc.nextLine(); System.out.println(array[0]);   this only prints out the first name  if the user inputs "John Will Smith" and later i want to print out   System.out.println (+firstName); System.out.println (+middleName); System.out.println (+lastName);   how do i go about individually updating the array or split it in a way I can grab what the user inputted?

What regex pattern would need I to pass to  java.lang.String.split()  to split a String into an Array of substrings using all whitespace characters (' ', '\t', '\n', etc.) as delimiters?


The situation is I have two schemas: A and B. I have a restricted user that I need to give a privilege do SELECT queries in B schema and just it. How can I grant this user?

I need to grant select permission for all tables owned by a specific user to another user.  Can I do this with a single command along the lines of:  Grant Select on OwningUser.* to ReceivingUser   Or do I have to generate the sql for each table with something along the lines of:   Select 'GRANT SELECT ON OwningUser.'||Table_Name||'TO ReceivingUser'   From All_Tables Where Owner='OWNINGUSER'


I created a wordpress theme i used free page builder called unyson used many plugins i built it successfully but when i copied whole theme and created zip file out of it and then uploaded it to newly installed wordpress i couldnt find my plugins although theme installed successfully but there was no plugins and any widgets that i created. can anyone answer why?? I am still learning wordpress templating m so confused and frustrated right now.

I'm working on a theme that includes some functionality I've developed as separate plugins (as I'm hoping to release them independently).  I'd like to include these plugins as part of the theme core and I've noticed that some developers include plugins as files or subdirectories along with their theme, but over time that can ultimately lead to maintaining two versions of the same plugin - one for the plugin repository, one for the theme - but I'd like to avoid that, if possible.  What's the best practice for including plugins as part of a theme?


Somehow I have a folder called "http:" on my computer, I can't delete or access or rename it. When I try to delete I get the message "The file name you specified is not valid or too long, specify a different file name".  I can't seem to do anything with that directory.  I have win 7 64 bit, I'm just trying to delete it normally.  Also, I checked properties > security, and it says the info is either unavailable or can't be displayed.

I've got a rather large number of files on my Windows drive that have a colon in their name. (These came from unpacking some Unix archives.)   When I try to delete them, Windows (XP) complains that the file does not exist, and refuses to delete it. This happens when trying to delete or rename it from explorer or the command line. Still, chkdsk does not complain about those files nor fix the problem.   Any ideas on how to get rid of them?


I have a setup where 180 jobs try to access oracle at the same time, i.e. they don't close connections quickly because they may be waiting for e.g. an ftp connection to open.  From oracle, I get the error:   Listener refused the connection with the following error: ORA-12520, TNS:listener could not find available handler for requested type of server   I believe this is due to too many connections open. This also affects the GUI of the application, which refuses login.  How can I determine a safe number of jobs to execute at the same time?  How should I handle the error? I tried to handle it by sleeping and retrying, but the only effect of this seems to be a that the TNS listener is always saturated and that the number of concurrently running jobs increases to 180.

What's the best way, using SQL, to check the maximum number of connections that is allowed for an Oracle database? In the end, I would like to show the current number of sessions and the total number allowed, e.g. "Currently, 23 out of 80 connections are used".


I saw this movie (or maybe it was a TV show) a long time ago.   All I remember is a larger number of people waking up in water and making it to the shore, I want to say they died and are waking up in an afterlife, but again the details are hazy. I remember there were these large towers near the shore the people got food and clothing from.   I was young, so I'm thinking it came out before 2004.  That's live action, not animated.

I am trying to find the name of a direct to TV movie, possibly a 2-3 part miniseries which I believe aired on the SciFi channel in the 90s. I don't remember who starred in it, but the movie opened with an astronaut attempting reentry whose shuttle ends up exploding. He awakes in a large bubble of air in a river and after reaching the surface and swimming to shore, meets several other people, from seemingly many different times throughout history (including one alien, who died on Earth).  Over the course of the movie, we learn the world is the afterlife, where everyone goes when they die. The major plot involves launching a steamboat (built by Mark Twain, no less) to travel up a river to the mountains, where the beings responsible for bringing everyone to this world are.  Does anyone know what the title of this movie/miniseries is?


I've come from a Postgres/MySQL world, so am wondering if there's a difference between these 2 queries in SQL server:  SELECT e.employee_id, s.salary FROM employees e INNER JOIN salaries s ON e.employee_id = s.employee_id   SELECT e.employee_id, s.salary FROM employees e, salaries s WHERE e.employee_id = s.employee_id

Is there any efficiency difference in an explicit vs implicit inner join? For example:  SELECT * FROM table a INNER JOIN table b ON a.id = b.id;   vs.  SELECT a.*, b.* FROM table a, table b WHERE a.id = b.id;


In the comics, Jane became the new Thor, but how did she become worthy of holding Mjolnir?

I just read online that, not too long ago,      Jane Foster    was shown worthy to wield Thor's hammer and is now being called Thor as a result. What events led to this? Did the original Thor urge her to attempt lifting the hammer, or did she just want to see if it was possible?


I've seen a definition of a manifold as a set $M$ with an atlas, that is, a collection of pairs $(U_\alpha,\phi_\alpha)$ where all $U_\alpha$ cover $M$ and the coordinate maps $\phi_\alpha$ are compatible. The only notion of topology in this definition is that $\phi_\alpha(U_\alpha)$  is an open set in $\mathbb R^n$ (I guess using the standard topology). In this definition we could identify $U_\alpha$ as an open set, so this defines a topology in $M$.   But most definitions require $M$ to have a topology previously defined so $U_\alpha$ are open sets from the beggining.  How are these two definitions related? It seems that the second definition allows many possible manifolds if we change the topology. Maybe the former is a particular case of the latter?

In John Lee's Introduction to Smooth Manifolds, a smooth manifold is defined as a topological manifold with a smooth structure. In do Carmo's Riemannian Geometry, a differentiable (smooth) manifold is defined by giving the smooth structure on merely a set $M$ and the author makes a remark that such smooth structure induces a natural topology on $M$.  Here is my question:     In Lee's definition, what is the relation between the topological structure and the smooth structure? Must the topology of the manifold (in Lee's definition) induced by the smooth structure in the way that do Carmo mentions?     The following are the definition and the remark by do Carmo mentioned above.


Assume I have the following list:  foo = ['a', 'b', 'c', 'd', 'e']   What is the simplest way to retrieve an item at random from this list?


Quite recently  (not to be confused with Ubuntu's Unity user interface) added an option to create a linux build. The result is a set of two executable binary files .x86 and .x86-64, plus a folder with some resources. I have exported my Unity game and it runs great on my Ubuntu machine.  I would like to publish the game on the Ubuntu Store, but I have no idea how to do it, and if it is possible at all. The  instructs me to use Ubuntu SDK for packaging into "click app". When I run the SDK, it asks me what kind of project I want to create, with lots of project type options (QML App, HTML5 App, Web App, Plain C Application made with gmake etc), but I cannot see any way to simply package the existing executable binaries exported from Unity.  Could anyone help? My game (don't want to advertise here) would be a great and free asset in the Ubuntu store, to the benefit of the whole community :)  To clarify: I don't want to publish sources of my app; and of course I am not able to publish any sources of Unity Engine player. I simply want to publish my free app to the store, which I have as binary.

As a developer of free software, I want to get my application into Ubuntu.  Should I provide a source tarball and ask for packaging? Or should I create a package myself? Should I target Ubuntu directly, or should I try to get into Debian and then into Ubuntu automatically?


LOGCAT Erorrّّّ      java.lang.NullPointerException: Attempt to invoke virtual method   'java.lang.String a.thebook.m_Model.new_book1.getnamebook()' on a null   object reference   in java Class  package a.thebook;  import android.content.Intent; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.widget.EditText; import a.thebook.m_Model.new_book1; ....   public class my_book  extends AppCompatActivity {         private new_book1 model;     private EditText  bookname1;        @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.my_book_activity);           EditText bookname1 = (EditText) findViewById(R.id.editTextbookname2);          bookname1.setText(model.getbookname()); ...    }   get values from firebase Database.  new_book1  package a.thebook.m_Model;   import java.util.Objects;   public class new_book1 {       public String author;     public String bookname;      public new_book1() {     }     public new_book1(String bookname ,String author) {         this.bookname = bookname;         this.author = author;      }     public String getauthor(int author) {          return this.author;     }     public String getbookname() {          return this.bookname;     }  }

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


I am travelling to the UK but my UK passport is about to expire and so would like ot enter the UK with my US passport.  How is allowed and legal?

I'm a British National (Overseas), which basically means that while I don't have the right of abode in the UK, I am permitted to visit the UK without a visa. However, my passport has expired, and while it's being renewed, the schedule is a bit tight.  At the same time, I'm an US Citizen, and since I'm only planning to visit the UK, I don't need a visa if I enter on my US passport.  I'm not familiar with UK immigration law, and given that this probably isn't too common a situation, the UK Border Agency website doesn't have an answer that I can can find, nor do they seem to have a contact form that fits my situation, so here's hoping someone knows—given that I'm a British National (Overseas), am I required to enter the UK on my UK passport, or can I just use my (valid) US passport?


Sleeping is important, but do students have the right to choose when they do so? Or should they let their parents decide the bedtime? Students above the age 12 need over 8 hours of sleep. It's important or you'll be drowsy, moody, upset angry etc. You will also be refreshed every morning, and have the ability to stay up longer without a proper amount.   If a student above that age has the right to choose their own bed time, they can choose when they feel is right when to go to bed or wake up. They may not get this right at first, but students need their own arrangement to take breaks, do school work, and other. Though an arranged bedtime by your parents may be difficult to follow, maybe by 9 p.m. This may not give you enough time to complete the tasks you've been thinking about doing.   The bedtime we can make ourselves may be 10, 11, or a bad time, 12. We'll learn from these mistakes and should be able to choose when we should sleep and wake up. Parents and or guardians shouldn't have to make a time or watch over us when. What do you think?

For teens, in this case a rising Junior in High School, is it appropriate to set a bedtime for him of 10PM? How does this compare with the majority of teens?


Is it possible to clone an object multiple times and then modify the original so all the clones modify at the same time? To be sure, I dont want to duplicate and modify each object one by one.

I have alot (like 50) duplicated meshes. i used SHIFT-D to duplicate the objects ,but then read that ALT-D saves memory. is there a way to link the mesh data (like using ALT-D) after i have used the wrong duplicate? attempting to go back and use ALT-D would take a long time.  The meshes i duplicated are all the same shape and size and only have different rotations.


I set up a fail2ban system on my server to restrict SSH access. It works fine, except that after entering the username on the unit, if I enter the password incorrect 3 times (my maxretry value), it continues to allow the user to attempt to log in. But if I remove exit from trying to log in as that user, and open a new session, I am now banned.   When using putty, I enter the target address (but not it's username  login as: user user@address's password: 1234 Access Denied user@address's password: 1235 Access Denied user@address's password: 1324 Access Denied user@address's password: 1234 Access Denied user@address's password: 1235 Access Denied user@address's password: 1324 Access Denied   In theory it should not let me log in after the 3rd try, but instead it lets me go through 6 tries, after which I get a popup about having too many authentication failures. If I then go back, fail2ban has properly blocked the device from access.   How can I get it set up so that I am kicked off right after the 3rd try?   Edit: I am aware of  question. However, I believe this is different because the poster there asks why it is not blocking at all. I am more worried about why it does not block login attempts that are already in progress.

So, I installed (and configured) fail2ban on three Ubuntu VPS servers. I configured (imo) a maximum of 3 failed login attempts (via Putty as root) within 2 minutes. Then I restarted the fail2ban service (according to ).    But when I look at my auth.log files in /var/log/ I still see 4, 5 or more failed attempts from certain IP's. So obviously I did something wrong as the IP is not blocked after 3 failed attempts.   It might have to do something with iptables, but that's where it gets a bit "foggy" for me..   Not sure how to setup a max-three-failed-login-attempts rule..  Additional: I see that the login attempts mostly have different ports for every attempt. Does that influence the count to max-three?  Because I see a port being "poked" twice and then no more attempts. Then the IP tries a different port (again 2 times). (all bots of course)


In Game of Thrones S08E06, we see        Arya deciding to conclude her character arc in Westeros     and set sail to West of Westeros. Jon asks her what is there in West of Westeros & she replies with something like Nobody knows?     Do we know what lies beyond West of Westeros? Do we have anything to go by from A Song of Ice and Fire Or from A World of Ice and Fire or other supplementary books from GRRM?

from the Game of Thrones intro sequence shows the Sunset Sea and the lands to the west of Westeros.  But what exactly is west of the Sunset Sea? Has anyone ever traveled there?


I am reading through force.com rest api developer guide      Obtain detailed information about a Salesforce object such as an Account or a custom object.      Obtain detailed information about Force.com objects, such as User or a custom object.   Can anybody explain what is the difference between salesforce object and force.com object?

What the difference between the two?  This description seems to be a bit out of date and underspecified.


How do I remove those pesky junk programs typically associated with a new computer? Going through Add/Remove Programs in the control panel seems very slow as it is only allowing me to uninstall one thing at a time.  I want to speed up this process, is there an application for massively uninstalling applications?   If so, does it have an internal database that can tell you what an application is for and any complications caused by uninstalling it?

Just been working on a new laptop today (Acer) and it was pre-installed with all sorts of crapware. Mostly games and "backup utilities" and McAfee. I had to manually uninstall about 30 apps via Vista's Programs and Features  So it got me wondering is there any way of mass uninstalling or queuing an app to be uninstalled? Through Vista/XP you need to wait for Install Shield or whatever to close before beginning to uninstall the next app. Took way more time than it should have.  Just another one of those Windows annoyances! Any help appreciated as I often need to do this when I come across a slow machine that's just been clogged with a bunch of useless apps


We are based in India Digital Marketing company , we want to target us, uk, middle east countries with the same website, language is English. How to tell to robots this from sitemap?

I have a multilingual PHP site. I have set English as the default language.  The language changes automatically according to the browser settings. If it is French, the site will be seen in French.  However in the Google search results, even if I have the browser in French, the English language appears in the results. How can I fix that?  To be clear I don't want to use subdomains or URLs like www.example.com/fr/. I would like it to work like Facebook.


I just got this error message:    Fair enough; I wasn't really paying attention to the duplicate link at the top of the suggested duplicate, just at the contents.  However, this question is  review queue with a vote to close as a possible duplicate of the question that got closed as a duplicate of this one.  Can we exclude these posts from the review queue (or if it's not easy, run a job to get rid of them)? As circular duplicates are  they'll just languish in the queue forever; generating confusion and more meta posts like this one (or ).  P.S. I clicked do not close; this isn't a question about what to do in this situation.

I just happened across , which has one close vote suggesting that it be closed as an exact duplicate of .  This suggestion is perfectly correct: these are exactly identical questions asked by the same user.  However, there's not much point in closing question A as a duplicate of B, since question B has already been closed as a duplicate of A.  Yet the close vote remains, doing nothing but wasting reviewers' time.  This is not the first time I've seen this happen, so I'd like to suggest that the Stack Exchange software should do something about it.  In particular, I'd like to suggest the following feature:     When a question Y is closed as an exact duplicate of another question X, any votes or flags to close X as a duplicate of Y should be automatically discarded.   Actually, I'm kind of surprised that the SE software doesn't do that already.  If anyone else thinks that this constitutes an actual bug, feel free to retag it.


A while ago I migrated from Chrome to Opera and I imported all of my bookmarks and settings into Opera, thanks to its powerful import tool. As a strategy for the probable future retro-migration, is there any way to import all of opera settings and other stuff back into Chrome?

Not the same thing:    While I know that I can use a service like Xmarks to synchronize them between the two browsers, and while I know that a method exists to export the bookmarks as HTML, then reimport them, are there any other methods?  Will Chrome look on install to see if there are any Opera bookmarks?


I have a circulation visa(valid till march 2020) issued by French Embassy valid from march 2017. In my application I mentioned I will be visiting France(from London) for 4 days in mid April (which I will be), but due to some Official training I have to visit Greece(from London) for first two weeks of April, come back to London and then travel to France(as per the dates mentioned in my visa application), can I do so ?  In a nutshell can I enter Greece on a schengen visa issued by France, which was earlier not the plan? Does it impact my entry at Greece or France?

In case, if I get a multiple-entry Schengen visa in one of the embassies in Ukraine, Kyiv - should my first trip be to the country which issued the visa?  Any there any requirements of this sort? Does this condition vary depending on embassy which issued the visa?  What are the possible consequences on not visiting that country first? Does it somehow depend on country where the embassy is (i.e. non-Schengen and not EU members)?


I tried to update the packages through the terminal and I get this error every time, david@david-Satellite-C55-B:~$ apt-get update E: Type '  Now the Software center doesn't work and I have a warning sign on the task bar next to the wifi symbol. Please help!

When I run sudo apt-get update get this output:   sudo apt-get update E: Type '<!DOCTYPE' is not known on line 1 in source list /etc/apt/sources.list.d/playonlinux.list E: The list of sources could not be read.   Also Ubuntu software Center is not opening.


$\mathbb{A}^{n}_{k}$ is read as "n-dimensional affine space over the field k" and an affine space is a set and action by a vector space. Should I interpret that $\mathbb{A}^{n}_{k}$ is shorthand meaning the set is $k^{n}$, the vector space is the coordinate space $k^{n}$ and the scalars of the coordinate space are in the field that is $k$? The confusing thing is it could indicate another type of affine space:  a set and action by n-dimensional vector space over the field $k$.  a set $k^{n}$ with action by a vector space that does or doesn't have $k$ as the scalars.   Another point is the dimension of an affine space is defined as the dimension of the vector space of its translations.

In my recent reading of various books and notes on algebraic geometry and scheme theory, I have come across three definitions of affine $n$-space over a field $k$:   $\mathbb{A}_k^n$ is $k^n$ 'without an origin'; $\mathbb{A}_k^n$ is simply $k^n$ with the Zariski topology (i.e. zero loci of sets of polynomials are closed); $\mathbb{A}_k^n=\operatorname{Spec}k[x_1,\ldots,x_n]$.   I know that things like the Nullstellensatz give us a nice way of going from one point of view to another when it comes to polynomial rings and affine varieties, but here I'm having some confusion. For $k=\mathbb{C}$ (which is algebraically closed, so things should all act reasonably nicely) we have that the points of $\operatorname{Spec}\mathbb{C}[x]$ are in bijective correspondence with points of $\mathbb{C}$, apart from the general point $[(0)]$. So it seems to me that these definitions can't all be the same, but searching for affine space on Google or in books leads to any one of the above definitions, depending on the level of the text.  Am I just making a silly mistake, or is there a difference in these definitions? If so, which one is the 'right' one?


quick question here about if this is possible or not. For a command line script I'm writing, I want the user to be able to enter a .py file as an argument, and I would like the script to import the .py file and seek out a specific variable contained inside.   My problem is that python expects an import statement to have the actual filename as the variable, which in my case I can't do (since I don't know the name of the .py file before the user inputs it):      elif training_file.suffix == '.py': # we expect partially annotated text here         import training_file   This doesn't work, and if I try to open it like I would a regular file, like so...      elif training_file.suffix == '.py': # we expect partially annotated text here         with open(training_file, 'r') as training_file:             for line in training_file:               ...   ... it just reads the raw text (as would be expected), and doesn't register python formatting. Is there a way to import and interact with a python file without knowing the name of that python file before starting the program? Is there a different way of doing this?  Thanks so much for any tips or guidance.

I'm writing a Python application that takes as a command as an argument, for example:  $ python myapp.py command1   I want the application to be extensible, that is, to be able to add new modules that implement new commands without having to change the main application source. The tree looks something like:  myapp/     __init__.py     commands/         __init__.py         command1.py         command2.py     foo.py     bar.py   So I want the application to find the available command modules at runtime and execute the appropriate one.  Python defines an __import__ function, which takes a string for a module name:     __import__(name, globals=None, locals=None, fromlist=(), level=0)      The function imports the module name, potentially using the given globals and locals to determine how to interpret the name in a package context. The fromlist gives the names of objects or submodules that should be imported from the module given by name.       Source:    So currently I have something like:  command = sys.argv[1] try:     command_module = __import__("myapp.commands.%s" % command, fromlist=["myapp.commands"]) except ImportError:     # Display error message  command_module.run()   This works just fine, I'm just wondering if there is possibly a more idiomatic way to accomplish what we are doing with this code.  Note that I specifically don't want to get in to using eggs or extension points. This is not an open-source project and I don't expect there to be "plugins". The point is to simplify the main application code and remove the need to modify it each time a new command module is added.


I have this sample file:  \documentclass[a4paper]{scrartcl} \usepackage[T1]{fontenc} \usepackage[utf8]{inputenc} \usepackage{ebgaramond} \usepackage{filecontents} \begin{filecontents}{bibliografia.bib} @Book{Zarlino1558, Title = {L'istitutioni harmoniche}, Author = {Zarlino, Gioseffo}, Publisher = {Francesco de' Franceschi}, Year = {1558}, Address = {Venezia}, }  @Music {Venturi1592, Author ={Stefano Venturi del Nibbio},   Title ={Il primo libro di madrigali a 5},   Address ={Venezia},   Publisher ={Angelo Gardano},   Year ={1592} }    \end{filecontents}   \usepackage{polyglossia}  \setdefaultlanguage{italian} \usepackage[backend=biber, style=authortitle, sorting=nyt]{biblatex} \usepackage{xpatch}  \let\mkbibnamelast\textsc%  \let\mkbibnamefirst\textsc%  \let\mkbibnameprefix\textsc%  \let\mkbibnameaffix\textsc  \renewcommand*{\newunitpunct}{\addcomma\space}  \xpatchbibmacro{publisher+location+date}{\setunit*{\addcolon\space}}%  {\setunit*{\addcomma\space}}{}{}  \DeclareNameAlias{sortname}{first-last}  \addbibresource{bibliografia.bib}  \begin{document} \section{Sezione} Questo è un test.\nocite{Zarlino1558} \nocite{Venturi1592}  \printbibliography  \end{document}   I would like to add a publisher field for my music type entries, which should appear between address and year, like for other books type entries.

Short question: How can I create a new entry type (@music) with fields for the composer, title, opus, editor, series, location and year?  \begin{filecontents*}{\jobname.bib} @music{citekey,     composer={Johann Sebastian Bach},     title={Motetten},     number={BWV 225--230}, %   opus={}, % no opus in this case     editor={Konrad Ameln},     series={Neue Bach-Ausgabe Serie III, Band 1},     loaction={Kassel},     publisher={Bärenreiter},     year={1965}, } \end{filecontents*}  \documentclass[ngerman]{scrartcl} \usepackage[style=authortitle]{biblatex} \bibliography{\jobname}  \begin{document} \cite{citekey} should look like  Johann Sebastian Bach: Motetten. BWV 225-230, hrsg von Konrad Ameln = Neue Bach-Ausgabe Serie III, band 1. Kassel: Bärenreiter, 1965  or in general  (composer): (title)[, (opus)][, (number)][hrsg. von (editor)][= (series)]. [(location)][: (publisher)][, (year)][.]  where (xxx)=field and [yyy]=optional  \printbibliography \end{document}