I noticed that there isn't newest questions in the questions page. But in front page, those new questions are displayed. Image:    Is this a bug?

SE is really acting up today, sometimes it doesn't show any questions in the questions tab in the sites.  I first noticed the problems when I opened my questions tab, and this shows up:        All I did was change the name of the question, and now meta stackoverflow thinks it's two questions.  Well the thing is, MSO actually created it as a new question!  Why?


If a question gets locked, there often is a meta discussion related to it, e.g. in the recent . While there is a  linking to , the "locked by..." message only links to meta in general:    Therefore, if such a discussion exists when (or gets created after) a post gets locked, the "visit meta" link should directly link there instead.

Locked questions get unhelpful messages like this:    My problem with this is that it implies that if I go to meta, I'll get more information about why that specific question is locked, perhaps finding a discussion of its merits.  However, the link just sends me to the main meta page, where I eventually realize there's nothing specific to the question.  Can we improve this situation?  Here are some suggestions (roughly in descending order of preference):   make the link point to an actual discussion, on meta, of that question make the link point to the site-specific FAQ, specifically the portion that covers what is/is not acceptable content make the link point to some discussion/documentation of what happens when a question is locked, and how the process is resolved/closed change the wording of the message so it doesn't imply that there is any specifically relevant discussion on meta remove "For more info visit meta" bit altogether


Gddrescue and testdisk are not on the 12.04 ISO that I downloaded and burned to a CD that I'm currently using to boot my system.  Where do I point apt-get to install those packages?  I have Internet access but got this results:  root@ubuntu:/# sudo apt-get install testdisk Reading package lists... Done Building dependency tree Reading state information... Done  E: Unable to locate package testdisk root@ubuntu:/#

How do I get to the Universe Repository in supported versions of Ubuntu?


I want to know if I travel to the Philippines and I have a layover in Seoul Korea,  do I need a visa to transit through to my next flight to philippines?

I am a Vietnamese citizen. I am planning to buy a round-trip flight ticket from Taipei to Los Angeles (America) and I will transit in Seoul airport.   Do I need a visa if I want to enter Seoul (not over 72 hours)?   My first route is TPE-ICN-LAX, do I need a visa if I stay one night in Seoul? My second route is LAX-ICN-TPE, do I need a visa if I stay one night in Seoul?  Of course, I have a valid US visa, and onward ticket that I booked.


I just completed the installation process for Ubuntu 13.04, and when it completed it said it needed to restart. After restarting, Windows 8 booted up, with no option for Ubuntu whatsoever.

I installed Windows 7, which ate Ubuntu's boot file. When starting up the computer, it now goes straight to Windows, without giving me the option of booting Ubuntu.   How can I get Ubuntu back?


Below are some example sentences:   Her only problem is a lack of confidence.  Lack of sleep had made him irritable.  If he fails it won't be for/through lack of effort (= he has certainly tried).  We won't be going away this year - lack of funds, I'm afraid.    What are the differences in those sentences?

"Mornings came and cast a blinding sunlight over everything, and he felt like nothing worthwhile could be accomplished."  For some reason, I feel like "a blinding light" is ok, but if its sunlight, then I should drop the "a" and write "cast blinding sunlight", but I'm not sure why I feel this way.   Can anyone offer some enlightenment?  edit - alternate phrasing, closer to being a literal translation: "Mornings came without warning, flooding the day with a strong sun, and he felt like nothing worthwhile could be accomplished."   I would still like an answer to the technical question of whether I should drop the "a", but would also appreciate knowing if anyone thinks option #2 is a better choice.


For $n>1$ consider real numbers $c_0>c_1>.....>c_n>0$. Prove that the polynomial $$p(z) = c_0+c_1z+.....+c_nz^n$$ in $\mathbb{C}$ has no zero whose modulus does not exceed $1$.

Let $p(z) = c_0 + c_1z + c_2z^2 + \dots + c_nz^n$ where $0 \le c_0 \le c_1 \le \dots \le c_n$.  I would like to show that all zeroes of this polynomial lie inside the unit disk by applying Rouche's theorem to the polynomial $(1-z)p(z)$.  I'm not completely sure how to do this. Using the given, information I can deduce that  $$|(1 - z)p(z)| \le |c_nz^{n+1}|$$  on the unit circle, but this doesn't really match the assumptions of Rouche's theorem.   Help would be appreciated.


I have a view listing nodes. I added 2 exposed filters. One is Content: title and the other is Content:Body. Then I have 2 input fields to enter some keyword to do searchs.   I need to have just one field and do the search in both fields: title and body. Can I do this?

I have two user profile fields "Last Name" and "First Name". I also have a user list views. I want to expose "Name" as filter which can search for both Last Name and First Name. How can I do single filter of combination of those two fields? Can I create it from views UI?  One possible way is to create another profile field "Name" which will be hidden in the form. On user save, I would combine the two field values into the "Name" field and then expose it as filter in the views. But this solution is hard coding and it needs to write hooks.


Trying to remember a Sci-Fi novel I read close to 20 years ago. The main character was a specially selected man who's lineage may have been tinkered with through the generations. He is made aware that he has the ability to physically modify his body to adapt to any environment or situation. This is done through concentration and mental visualization of the desired modification and ingesting large quantities of food that aid in facilitating these physical changes.  Somehow, he finds himself teleported or transported to an alien planet where the animals are very dangerous. The planet itself, if I remember correctly is many times larger than the Earth is and the main character decides to modify his body to allow him to fly. Unknown to him there is a very large and fast flying predator that nearly kills him. In the process of recovering he modifies his body to something similar to an armored rhinoceros. He manages to jump onto the back of one of these flying predators to speed his travel.  The main character has developed an intrusive probe that he inserts into the brain of the flying predator and in the process discovers it's somewhat intelligent. They travel together for some time but this is where my memory of the book ends.  As far as the title and author are concerned... I believe the author may have had the first name of Peter and that the title began with a "T" beyond that....I have nothing else. Thank you to everyone who may know something and if this same novel has been identified previously, my applogies.

Looking for a book I read in the 90's (not sure if it was published in the 90's or not).  The story as far as I can remember goes like this. Human-looking aliens evolve on a very hostile planet. They encounter some big bad threat and they cast about for help. They encounter a rich industrialist on Earth and they send a woman to recruit him. She teaches the guy to use magic and how to transform his body. They build a ship and travel to her planet but just before they arrive, she vanishes and he crash lands on this hostile planet.  He goes through many trials and tribulations in order to get to her and eventually he has enough and uses the ability she teaches him on how to transform his body. He transforms himself into a half-man, half-dragon-like creature which allows him to travel to the other side of the planet to get to the girl. On the way he manages to neurally link into a large flying creature that flies very fast, only to discover that it is intelligent and they soon become friends. When he gets to the girl she doesn't recognise him so he gets mad and starts attacking only to realise that it's all been a test set up by these people to allow him to reach higher levels of magic.   There were supposed to be sequels but I never got around to reading them.  I remember the cover art depicted a large dragon like creature with a torso of a man and a woman standing in front of it looking back at him.  Any idea what this book may be?


Technically the question was  prove that if $R^m$ $\cong$ $R^n$, then m=n.  My proof was basically considering the case m>n, then consider an isomorphism $\phi$, then the image of the basis of $R^m$ under $\phi$ must still be linearly independent, but $R^n$ has a rank of n which is less than m, which will make the images of the basis of $R^m$ linearly dependent, contradiction.  My professor's comment of my solution was "long answer but you've shown nothing".  I do not understand what exactly is he looking for or the "proper" solution. Can anyone help explain?  edit: R is commutative

How can i show that two $R$-modules of finite rank are isomorphic if and only if they have the same rank, i.e., $R^n \cong R^m$ iff $n=m$.


Let $G$ be a finite group. For each positive integer $m$, if $x^{m}=e$ has at most $m$ solutions in $G$, $G$ is cyclic.   What I have thought is that $n=\sum_{d\mid n}\phi(d)$ can be used to solve this and showing that $|G|$ order element in $G$ exists is enough.

Fraleigh(7th ed) Sec10, Ex47. Let $G$ be a finite group. Show that if for each positive integer $m$ the number of solutions $x$ of the equation $x^m=e$ in $G$ is at most $m$, then $G$ is cyclic.   I tried it a few hours but I couldn't solve it. So I read the solution. But I narrowly understood the solution, and it's still unclear to me. How can I solve it?


I have tried to remove all the headers before chapter 1 and it works on all of the pages but 1. I have around 10 pages before chapter 1, and page 7 adds the header.  Here is my code so far:  \makepsmarks{ase_report}{%   \renewcommand\chaptermark[1]{%     \markboth{%       \ifnum \value{secnumdepth} > 1       \if@mainmatter %        \@chapapp\ \thechapter: \ %       \fi       \fi       ##1}{}}%    \renewcommand\tocmark{\markboth{}{}}%   \renewcommand\lofmark{\markboth{}{}}%   \renewcommand\lotmark{\markboth{}{}}%   \renewcommand\bibmark{\markboth{\bibname}{\bibname}}%   \renewcommand\indexmark{\markboth{\indexname}{\indexname}}%   \renewcommand\sectionmark[1]{\markright{##1}}%   \renewcommand\subsectionmark[1]{\markright{##1}}%   \renewcommand\subsubsectionmark[1]{\markright{##1}}% }   I am using frontmatter and mainmatter. Front matter is defined on page 1 and front matter is defined in the beginning of chapter 1. I hope you can help me.  Note: What I see in the header is "0.0" and nothing more.

I wrote my diploma in LaTeX using Lyx, but now I have big problem to fit the output to universities' standards.  I need to remove Part/Section... title from header, I found that using:   \pagestyle{empty}   does the job, but it also removes page numbers, and I spent more than an hour trying to fit them together, especially that in some pages I need no page numbers, while in others has to start from some number, so I'm using:  \setcounter{page}{3}   which also conflicts with the first command.  Any help will be highly appreciated, because I need to print it today, thank you in advance.


In Logan, Charles Xavier suffers from dementia. He has seizures which seem to cause shock waves, resulting in headaches, and time slowing down. Does he have this power in the comics?

In the X-Men movies, Professor Charles Xavier exhibits the ability to freeze minds, effectively stopping time for people on a fairly large scale, freezing everyone in the Oval Office and an entire food court full of people in X-2: X-Men United.  When the movie was released, many fans were surprised/confused at this apparent new power.  Has this ability ever been exhibited by Charles Xavier in the comics before, or since?


I'm using the vanilla gnome-session on ubuntu 18.10 but i would like to use the default ubuntu gnome-shell theme (yaru) instead of the gnome default.   How i can do this?  Thanks in advance.

I've installed the latest 17.10 Ubuntu and then used   sudo apt install gnome-session   to get rid of Ubuntu's modifications, as described .  Although I prefer to have a vanilla GNOME experience, Ubuntu's  is very appealing. Unfortunately, I can't find this theme in GNOME Tweaks. The only GNOME-Shell theme that is present there is GNOME's default one.  Does somebody know a convenient way to install Ubuntu's new GNOME-Shell theme?


Lets get on to it!   we know that a wave is simply a disturbance in a certain surface or any kind of a field and this should be common to every wave even light. The problem comes with the property of light that it can travel without the necessity of any material medium i.e. vacuum.  So when light is travelling in a vacuum how can it be travelling as a disturbance i.e.wave when there is no substance to create a disturbance?(Or How can something i.e. light travel through nothing as a wave?)   I know for sure that vacuum cannot act as a field for disturbance to happen or take place on it because it is not a "thing" it is just the absence of "anything". Please answer in a understandable manner.

As I understand it, electromagnetic waves have two components which are the result of each other, i.e., when a moving electric charge creates a changing magnetic field at point X then a changing electric field is created at point Y and this repeating process is what creates EM waves, so therefore, it requires no medium. Is my understanding correct?  One thing that I'm surprised to know is that light is also called an electromagnetic wave.  Does this include light of any kind, for example: light from a bulb, a tube, and also from the Sun? How do they contain electric and magnetic fields?


I've been searching for hours for real, I couldn't find any where I was wrong. It works when I don't do it as a template, but it gives an error when it is a template. this is header file #ifndef Queue_h #define Queue_h   template<class T> class Queue { public:     Queue();     ~Queue();     bool isEmpty() const;     int size() const;     //Enqueue: Items are added to the back of the queue     void enqueue(const T& newItem);     //Dequeue: Items are removed from the front of the queue     void dequeue();     //Get Front: Take a look at the first item struct QueueNode {         T item;         QueueNode *next;              };     QueueNode *front_p;     QueueNode *rear_p;     int _size; };  This is c++ file #include <stdio.h> #include "Queue.h" #include <iostream> #include <string>  using namespace std;  template <class T>  Queue<T>::Queue():front_p(NULL), rear_p(NULL), _size(0){  };   template <class T> Queue<T>::~Queue() {     // dequeue until queue is empty     while ( _size > 0 )         dequeue(); };   template <class T> bool Queue<T>::isEmpty() const{     return front_p == NULL; };  template <class T> int Queue<T>::size() const{     return _size; };  template <class T> void Queue<T>::enqueue(const T& newItem) {      // create a new node     QueueNode *newPtr = new QueueNode;     // set data portion of new node     newPtr->item = newItem;     newPtr->next = NULL;     if ( 0 == _size )         front_p = newPtr;     else        // insert the new node at the rear of the queue        rear_p->next = newPtr;       // in either case set rear to point to new node and increment num_items    rear_p = newPtr;    _size++;  };   template <class T> void Queue<T>::dequeue(){     if ( 0 == _size )     {         cout<<"empty"<<endl;         return;     }         else { // queue is not empty; QueueNode *temp = front_p; if ( front_p == rear_p ) {     front_p = NULL;     rear_p = NULL; } else     front_p = front_p->next; temp->next = NULL; delete temp; _size--; } };  This is the main part. The problem starts here, either there is an error in the cpp file or I am initialize it incorrectly. #include <iostream> #include <stdio.h> #include "Queue.h" #include "SomeClass.h" using namespace std;   int main(int argc, const char * argv[]) {               Queue<int> q1;     Queue<SomeClass> q2;           return 0; }  error message Undefined symbols for architecture x86_64:   "Queue<int>::Queue()", referenced from:       _main in main.o   "Queue<int>::~Queue()", referenced from:       _main in main.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation) Undefined symbol:queue<int>::Queue();

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 am studying parameters generated by the method of Ordinary Least Squares, in particular, a parameter's associated standard error.  suggests calculating   $$s^2=\frac{S\left(\hat\beta\right)}{n-p}=\frac{\rvert\rvert y-X\hat\beta\rvert\rvert^2}{n-p}$$  describing this as      the standard error of the regression (SER), or standard error of the equation (SEE).   This, however, is not sufficient to calculate the standard error for a given parameter.   I found , which suggests     For each parameter, the standard error can be obtained by:   $$s_{\hat \beta _j}=s \sqrt{C_{jj}}$$       where $C_{jj}$ is the j$^{th}$ diagonal element of $(X'X)^{-1}$ (note that $(X'WX)^{-1}$ is used for weight fitting).    Note, that using this technique yields precisely the same standard errors as those summarized by the lm method in R.  Where does this $C$ come from? I have been reading about this for days, and this is the first reference I have seen to this matrix.

I am reading a book on linear regression and have some trouble understanding the variance-covariance matrix of $\mathbf{b}$:    The diagonal items are easy enough, but the off-diagonal ones are a bit more difficult, what puzzles me is that  $$ \sigma(b_0, b_1) = E(b_0 b_1) - E(b_0)E(b_1) = E(b_0 b_1) - \beta_0 \beta_1 $$  but there is no trace of $\beta_0$ and $\beta_1$ here.


I'm looking to read digital and analog pins on one arduino from another arduino. I believe that as long as they share a common ground connection this should work fine. I'm aware of I2C and I have used it for other projects, but for this I am more interested in just making the connections.  I was wondering   Has anyone had experience with this? Will I damage anything if I do this?

I am working on an MSP430 project that requires me to route the output of one peripheral into the input of another peripheral. Thus, I have two MCU pins connected directly to each other. This looks suspicious to me since there is the possibility of a programming error causing both to be (possibly conflicting) outputs. Also, there is the issue of startup and programming states.  In the worst case, if one pin is driving HI, the other is driving LO, the GPIO pins generally have way more sink capability than source capability... so it'll be somewhat like taking a HI output and shorting it to near-ground. Which is bad... but how bad is it? Is it likely to cause damage to the MCU?  I often see examples on the web of people using Arduinos to light an LED between two pins without a resistor, and I haven't heard of any stories of anyone frying anything but the LED. Clearly you wouldn't want to do this in a product, but do manufacturers generally try to protect the MCU from GPIO pins being overloaded anyway?  Thinking about it in retrospect, putting a current-limiting resistor between the two pins would have prevented any worries, but even a minor hardware change is a very difficult thing to do at this point.  For future reference and the benefit of posterity, does anyone have any other ideas about the proper way of minimizing the risks of connecting two MCU pins together, and more generally, minimizing the risks that come from the possibility of overloading a GPIO pin?


I can't get my head around subspaces despite having studied on them quite a lot. Here goes:  The problem statement, all given variables and data  Give an example of a non-empty subset U of R^2 such that U is closed under scalar multiplication but is not a subspace of R^2.  Attempt at a solution  So a set such as [x1, x2] | x1 >= 0 is NOT closed under scalar multiplication but is closed under addition. I get this but I cannot find an answer in reverse.  A wild guess is x1 + x2 + 2 = 0. I could multiply it and 2x1 + 2x2 + 4 = 0 would still hold true. However, if I wish to perform an addition on it, I don't exactly understand what I add to what equation exactly.. it's all so bogged up. Help would be appreciated. :-)

$Q$: Find a subset of $ \mathbb R^3$ which is closed under $*$, but not $+$. $A$: The set $\mathbb R$$u$ $+$ $\mathbb R$$v$, where $u$ and $v$ are linearly independent vectors in $ \mathbb R^3$. Here $ \mathbb R$$w$ = $\{aw: a \in \mathbb R\}$ for a given vector $w$. This is closed under $*$, but not $+$.  By  $u$ and $v$ are linearly independent vectors in $ \mathbb R^3$  do they mean two sets of linearly independent vectors $u$ and $v$ in $ \mathbb R^3$ where $u$ could be  $u = \{(1, 0, 0), (0, 1, 0), (0, 0, 1)\}$? Generally, please help me understand how this set is not closed under $+$. Thanks.


I need to get the path of script.   I can do this manually with pwd but after searching online and I found this script:   DIR=$( cd $(dirname $0) ; pwd)   I don't know what it means. Can someone please explain?  edit:this script is different from that script

How do I get the path of the directory in which a  script is located, inside that script? I want to use a Bash script as a launcher for another application. I want to change the working directory to the one where the Bash script is located, so I can operate on the files in that directory, like so: $ ./application


I've managed to render PNGs which have my machine on a transparent background, but I want to have a video of it.  I've tried lots of settings to no avail....the film/transparent setting doesn't seem to do anything.  Every vid I've rendered, whether it be straight from Blender Render or Cycles Render or via creating a film strip from the PNGs via Video Editor and creating a vid from there, turns up with a black background from my scene.  Whats the trick?  Thanks!

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


Sorry, I'm new to python, and I'm struggling finding what I need. I'm also sorry on how I wrote the title (probably the same reason why I can't find what I need, I don't know what to search for..) The question is really simple, but I don't know if it can be done. I have a python file (bot.py) which reads some variables from another file (a configeth.py file). import configeth  so, is there any way for me to edit the "configeth.py" file while the bot.py is still running, and tell him to import and use the updated file without having to kill the bot and start it again??? thanks a lot, really appreciated.

I have a long-running Python server and would like to be able to upgrade a service without restarting the server. What's the best way do do this?  if foo.py has changed:     unimport foo  <-- How do I do this?     import foo     myfoo = foo.Foo()


The good ol' Maxwell Equations have two very big concepts: the $\vec{E}$ and $\vec{B}$ fields. But it can be shown, adding relativity into the stew, that what we call the $\vec{E}$ and $\vec{B}$ fields are just a single Electromagnetic field. When talking about the same frame of reference, this Electromagnetic field behaves just like what we call the $\vec{E}$ field. And if the charge is viewed from a different frame of reference, after proper Lorentz Transformation, another force field seems to come into play which is what we call the $\vec{B}$ field. It's not a new concept.   But according to the :     Relativistic electromagnetism is a modern teaching strategy....      Teaching strategy? Why isn't such an approach used more commonly? This would make understanding Electromagnetism more intuitive since all that's required that way is $\nabla\cdot\vec{E} = \rho_v/\epsilon$ (Gauss' Law) which is not to hard to explain. Why are Maxwell's Equations and $\vec{E}\,\vec{B}$ fields not regarded as "approximations" or "tools to make electromagnetism simpler"?   Moreover, permanent magnets work because of electron spin. Why does electron spin arise?It's because of the bispinor wavefunction result of the Dirac Equation (going into quantum mechanics here), which is like older QM, plus.......? Special Relativity. Damn. Its pretty easy for me to say here that all magnetism is a result of basic non-relativistic ideas plus relativity, but still this idea is not given as much attention as seeing how important it is. Is there a reason?

It is fairly easy using basic special relativity to arrive at the conclusion that the magnetic force effect on nearby charges of wires carrying currents on nearby charges is only due to the length contraction in certain inertial frames from the point of view of charges, which gives rise to a perceived change in charge density. However, we structure the (classical field) laws of electromagnetism in Maxwell's laws using a B field.  My question is, is it possible to formulate Maxwell's equations only in terms of Lorentz transformed E fields? If not, why not?


$$\sin(\theta)+ \sin (2\theta)+\ldots+\sin(n\theta).$$  Find the identity? Set $z=e^{i\theta}$.  Can someone point me in the right direction as to where to start/go from.  So far I have  $$\frac{1-e^{i\theta(n+1)}}{1-e^{i\theta}}.$$  And I am stuck as to where to go from here.

I'm trying to solve    So far I've done the first part, evaluating the summation ;  where a is just n. I'm not sure where to go from here or what it even means deduce the second summation. I understand that the summation of simply $$\sum\limits_{k=0}^n\cos(kx)$$ is derived from looking at the real part of  $$\sum_{k=0}^n{\rm e}^{ikx} $$I'm guessing they want me to see how the second summation in the question is defined by 'playing around' with the original?


I currently have it in both locations, but figure this is incorrect. The problem is, when I try to remove it from sites/all/modules the superfish module complains, and says that it's needed.   What am I doing wrong?

Where should I be extracting the  module, sites/all/modules or sites/all/libraries?


This strikes me as strange... there's a ... and then a bounty was offered. (as my answer was submitted before, I understand it was ineligible for auto-selection)  However, then my answer was accepted, and the bounty seems to have not been awarded, and thus the bounty went to another answer.  This seems unusual to me. Not that I mind - I'm not going to lose sleep over 100 rep - but it struck me as flat out confusing.  Even if the accepted answer is from before the time the bounty was offered, in the event of an un-awarded bounty, shouldn't the accepted answer take precedence? Or is this by design, and I'm just missing something?   suggests that "the assumption is that the bounty owner was not satisfied with any of the existing answers at the time the bounty was started" but I can't help but wonder that if that's the case... why would they accept one?  (or am I completely misinterpreting everything, and that bounty was in fact not auto-awarded?)

It's possible to offer and award bounties of reputation on questions.   What is a bounty? How can I find questions that have a bounty attached? How do I start a bounty? When can I start a bounty? Why is the system requiring me to choose a bounty amount that's higher than the minimum? Can I use Markdown formatting in the bounty remarks? Can I edit the remark? How long is the bounty period? How do I award a bounty? Can I award a bounty to my own answer? Can I award a bounty to an old answer? If I offer a bounty on someone else's question, can I award the bounty to their answer? After awarding the bounty, can I remove it or move it to another answer at a later time? What happens if there's no answer after the bounty period? What happens if I feel my question is still unanswered? What is automatic awarding? Are bounty awards exempt from the 200 points/day reputation limit? How does Community Wiki mode affect bounties? How does user deletion or post dissociation affect bounties? Can I award a bounty to an answer from a deleted user or one where the author was dissociated? Can I offer a second bounty after the first one has expired? Can I raise my bounty? What happens if a bounty question is closed or deleted? Why can't I vote to close or migrate a bounty question? What happens if I delete my account while I have an active bounty? Do I keep an awarded bounty when I delete my answer? What happens if a question where I awarded a bounty later gets deleted or migrated? Can I cancel my bounty? Can I affect / divide / share part of my bounty to two (or more) users? How many outstanding bounties can a single user have?      See also:  in the Help Center


Let $\mu$ be a measure on Borel-sigma algebra on $[0,1]$ which has the property that for every $f$ continuously differentiable, we have   $$ \bigg| \int f' \ d\mu \bigg| \leq  \left (\int_{0}^{1} f(x)^2 \ dx \right )^{1/2} $$  Then prove that :   (i) $\mu$ is absolutely continuous w.r.t Lebesgue measure on $[0,1]$.  (ii) If $g$ is the Radon-Nikodym derivative of $\mu$ w.r.t Lebesgue measure, then there exists a constant $c$ such that $$ |g(x)-g(y)| \leq c |x-y|^{1/2} $$  Can anyone help me with this ? I am unable to proceed in any fruitful direction.  If I have $m(A)=0$, who do I use the above condition to show $\mu(A)=0$ ? All I have is an integral over $[0,1]$.

Suppose that $\mu$ is a measure on the Borel $\sigma$-algebra on $[0,1]$ and for every $f$ that is real-valued and continuously differentiable we have  $$ \left|\int f'(x)~\mu(\text{d}x)\right|  \leqslant \left(\int_0^1 f^2(x) ~\text{d}x\right) ^{1/2}. $$  (1) Show that $\mu$ is absolutely continuous with respect to Lebesgue measure on [0,1].  (2) If $g$ is the Radon-Nikodym derivative of $\mu$ with respect to Lebesgue measure, prove that there exists a constant $c>0$ such that $$ \left|g(x)-g(y)\right|\le c\left|x-y\right|^{1/2},~~~~~~x,y\in[0,1]. $$  Attempt  The inequality given reminds me of Jensen's inequality but I've no idea how to use it on (1).


I installed some additional desktop environments in ubuntu 18.04, and I don't know if this has something to do with it, but around the time installing these desktop environments, I discovered that my boot screen was not the standard ubuntu one, rather the ubuntu budgie boot theme. I tried to fix it, but I messed up some plymouth related stuff, so I ended up reinstalling the default plymouth theme for ubuntu 18.04.  Now I discovered that my grub menu background is black, not the standard "ubuntu-purple", and I don't know if it has something to do with the plymouth related stuff, but anyways, the question is: "how can I fix the grub menu back to the defaults?".   My GRUB menu version is 2.02 (output of grub-install --version is grub-install (GRUB) 2.02-2ubuntu8.13), and I don't know if this is the standard version of GRUB in ubuntu 18.04, so that is another question I'm wondering about.  Thanks for all answers!

How to do this manually, not installing any tools?


Numlock is not enabled on my ubuntu gnome 16.10 login screen. It was perfectly working with 16.04.  I tried several tricks but none of them works: - adding numlockx in /etc/rc.local => no difference - adding numlockx (with a little script) in /etc/gdm3/Init/Default => No difference - adding numlockx on in startup apps => no effect. ....  Any idea on how to enable numlock at login on ubuntu gnome 16.10 ?  (after login, numlockx on / off works perfectly).

I am trying to force numlock to be on upon initial boot at the login screen on Ubuntu 12.04. The only solutions I have found so far switch numlock on only after initial login.  I'm looking to force numlock to be on when the login screen is displayed, and before the user has logged in. Can anyone assist?


Do you have a version of Ubuntu that works with Windows 8? Ubuntu 12.04.3 and 13.10 can not detect windows 8 on my hard drive and want to erase everything.

I'm absolutely new to Linux. I would like to know how to install Ubuntu alongside the pre-installed Windows 8+ OS.  Should I do it with Wubi, or through the Live USB/DVD?  What steps do I need to take to correctly install Ubuntu?


In an application I'm developing, a user is allowed to fetch a value using a button. Upon the value being successfully fetched, I need to notify the user. I used the following sentence.  The value was fetched successfully.  Upon reviewing it, my co-worker suggested the following sentence, which doesn't sound right to my ear.  The value is fetched successfully.  Appreciate if someone can clear up the difference between these two sentences. Are both grammatically correct? If so, which is more appropriate to use for this case?

Non-native speakers often get confused about what the various tenses  and aspects mean in English. With input from some of the folk here I've put together a diagram that I hope will provide some clarity on the matter.  I offer it as the first answer to this question. Consider it a living document. Input is welcome, and good suggestions will be  incorporated into the diagram.    Nota bene: What this is not is a discussion of whether there are  more than two tenses in English. , to which this question is not intended to supply arguments one way or the other.  Here, the aim is to provide an overview of what constructions English-speaking people use for conveying information about actions referring to past, present, and future, and to provide it first and foremost to precisely the people who are likely to use "tense" as a catch-all term in their search, rather than to linguists who know better.  Breaking News There is now an excellent ELU blog article titled  . It is highly recommended reading.


Kindly guide me through to configure environments.yaml file for hpcloud so that juju shall access HPCloud for deploying instances.  thanks,  Guru

HP Cloud has a new cloud service out based on Open Stack. How can I configure my environments.yaml to connect to the new service?


I'm sorry i'm newbie at Ubuntu, i'm using Ubuntu 14.04 LTS with my laptop Asus N43SL  I want to share my wireless internet from my laptop as Access Point, why? because i using android smartphone, so i can't create ad-hoc wireless  i know there's so many thread here about creating Access Point but sorry i really not get it..  I'm following this site to create it    but when i start the hotspot, terminal always show  Starting Wireless Hotspot...   please is there a script to do this or an application to do it easier? give me the link if there is

I've read , and carefully followed the instructions provided. I am sure the wireless card in my laptop supports going into wireless access point mode. But unfortunately, when I use the following command to start hostapd service it throws an error:   $ sudo service hostapd stop  Starting advanced IEEE 802.11 management hostapd                      [fail]    The instructions mentioned above said this could possibly be because my wireless card does not support the g mode, and provided the wiki of hostapd. But what is g mode? I tried to switch to a, or b mode, but it just didn't work.  Can anyone help with this or recommend a tool like connectify in windows ?  ps. I am using Ubuntu 12.04, 32 bit. I have an ADSL wired network, and I want to share it by setting my laptop into a WiFi hotspot with  my windows phone.


How can I make my Unity desktop like this picture?  I want the position of close/minimize buttons to be on the toolbar beside the address bar like this:    This image looks like Gnome desktop but Ubuntu's menu is like this:     I mean, the close button in Ubuntu is on the top of the address bar but in first image the buttons are integrated in the address bar.

I'm fairly excited for Unity, as it looks like a promising new direction for Ubuntu.  However, I do have a concern - will it be possible to use Unity without the global menu?  I have my window manager set to focus-follows-mouse/sloppy focus, and find the productivity gains to be immense. Sloppy focus is incompatible, however, with global menus, as it is possible for the focus to change while you move from window to menu.  Will Unity support an option to use window menus while still using Unity?


In the marvel movies, they reference how Bruce Banner measures his heart rate and that if it gets too high, that he becomes the Hulk. In the avenger movie, he states how his trick is he is "always angry".   My original understanding was that Bruce becomes the Hulk when he gets angry. But if he is always angry, then this isn't the case, and if its related to just his heart rate, then I'm curious if the Hulk can have sex, as heart rate increases when you approach climax.  Can Bruce have sex without becoming the Hulk?  Clarification: This is not a question if they can procreate. That is answered in other links, where he has a kid with Shehulk, and an alien chick. They also have a 3rd kid that was created from his DNA and a 4th which is just a rumor. Based on these facts, the only two that are confirmed through traditional methods (sex), where not with ordinary people, which means he may turn into the hulk upon orgasm. The question is can he have sex without becoming the hulk. Him having sex as the hulk is one thing, but him having sex to completion as Bruce is another.

I just watched Planet Hulk. At the end the Hulk ends up with someone seemingly almost as powerful as he is. Are the Hulks (Green, Red, and She-Hulk) able to have children?


In a terminal window any smaller than fullscreen, if I type in a long command it starts overwriting the current line I'm on. If I type an additional line's worth, it finally moves to the next line. Does anyone know how to fix this?   This is what happens visually:     Edit: These are my prompt settings:  PS1='\[\e]0;\u@\h: \w\a\]${debian_chroot:+($debian_chroot)}\u@\h:\w\033[1m`__git_ps1`\033[0m\$ ' TERM=xterm   .bashrc:    if [ "$color_prompt" = yes ]; then     PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ ' else     PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\033[1m`__git_ps1`\033[0m\$ ' fi  # If this is an xterm set the title to user@host:dir case "$TERM" in xterm*|rxvt*)     PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1"     ;; *)     ;; esac

Something I have noticed in Ubuntu for a long time that has been frustrating to me is when I am typing a command at the command line that gets longer (wider) than the terminal width, instead of wrapping to a new line, it goes back to column 1 on the same line and starts over-writing the beginning of my command line. (It doesn't actually overwrite the actual command, but visually, it is overwriting the text that was displayed).  It's hard to explain without seeing it, but let's say my terminal was 20 characters wide (Mine is more like 120 characters - but for the sake of an example), and I want to echo the English alphabet.  What I type is this:  echo abcdefghijklmnopqrstuvwxyz   But what my terminal looks like before I hit the  key is:  pqrstuvwxyzghijklmno   When I hit enter, it echos  abcdefghijklmnopqrstuvwxyz   so I know the command was received properly.  It just wrapped my typing after the "o" and started over on the same line.    What I would expect to happen, if I typed this command in on a terminal that was only 20 characters wide would be this:  echo abcdefghijklmno pqrstuvwxyz   Background: I am using bash as my shell, and I have this line in my ~/.bashrc:  set -o vi   to be able to navigate the command line with VI commands.  I am currently using Ubuntu 10.10 server, and connecting to the server with Putty.  In any other environment I have worked in, if I type a long command line, it will add a new line underneath the line I am working on when my command gets longer than the terminal width and when I keep typing I can see my command on 2 different lines.  But for as long as I can remember using Ubuntu, my long commands only occupy 1 line.  This also happens when I am going back to previous commands in the history (I hit Esc, then 'K' to go back to previous commands) - when I get to a previous command that was longer than the terminal width, the command line gets mangled and I cannot tell where I am at in the command.  The only work-around I have found to see the entire long command is to hit "Esc-V", which opens up the current command in a VI editor.  I don't think I have anything odd in my .bashrc file.  I commented out the "set -o vi" line, and I still had the problem.  I downloaded a fresh copy of Putty and didn't make any changes to the configuration - I just typed in my host name to connect, and I still have the problem, so I don't think it's anything with Putty (unless I need to make some config changes)  Has anyone else had this problem, and can anyone think of how to fix it?  Edit  It was my .bashrc file.  I've copied the same profile from machine to machine, and I used special characters in my $PS1 that are somehow throwing it off.  I'm now sticking with the standard bash variables for my $PS1.  Thanks to @ændrük for the tip on the .bashrc!  ...End Edit...


Ubuntu 12.04 Unity greeter had introduced the selected user dynamic wallpaper which allowed, when selecting a user from the available users list in the login screen, the wallpaper to change to reflect the selected user's desktop wallpaper.  Apparently that feature has been disabled by default since Ubuntu 12.10.  How do I enable that feature in Ubuntu 13.04?

How do  I create a desktop wallpaper slideshow with my own set of images?   With the images coming from a pictures folder, or pre-selected With the images displayed in order, or randomly With the images changing every few minutes, or after random periods of time


To use  as you would require when using the  with large numbers (100,000+), it calls for some very large calculations.  When I multiply two large numbers (eg: 62574 and 62574) PHP seems to cast the result to a float. Getting the modulus value of that returns strange values.  $x = 62574 * 62574; var_dump($x);          // float(3915505476) ... correct var_dump($x % 104659); // int(-72945)  ... wtf.   Is there any way to make PHP perform these calculations properly? Alternatively, is there another method for finding modulus values that would work for large numbers?


I have a 2048x2048 map and if I path-find to an unreachable location, it makes the pathfinder go through every node on the map which freezes the thread for 4 seconds.  How can I reduce that time?   I'm using JPS It's a dynamic map (it changes at runtime)

I am making a simple tile-based 2D game, which uses the A* ("A star") pathfinding algorithm. I've got all working right, but I have a  performance problem with the search. Simply put, when I click an impassable tile, the algorithm apparently goes through the entire map to find a route to the impassable tile—even if I'm standing next to it.  How can I circumvent this? I guess I could reduce the pathfinding to the screen area, but maybe I am missing something obvious here?


I want to make use of the word sculpture. Here is an example:  He can make his sculpture out of a plaster.  Grammatically, is  my example correct? Can I use 'by' or 'from' or 'with' instead of 'out of'?

Can we use the word "from" (again) instead of "out of" in the following sentence? Does it not make sense if we use or it was not used in order to avoid repeating the word from ?     ...Here's the formal definition from the ABC Institute out of their   book called...     How about this sentence     ...Here's the formal definition from  their book called...


All the water outlets in my condo can only supply hot water for at most 2 mins and then I am left with cold water. I changed my gas water heater 2 days ago, but the problem continues. I was desperate when I thought the problem was finally resolved but was left with cold water again during a shower. Do anybody happen to know what is going on here ? Thank you a lot.

Hoping someone can give me some thoughts on what might be going on here so I can be a bit more informed when I call a plumber.  Situation is, we got our water heater replaced a few years back and ever since this has been an issue. It's more noticeable when it's cold outside it seems, but still seems to be a year round problem. Whenever we  use hot water, we basically run out of it within minutes. In order to get an acceptable amount of hot water (enough to take a 10 minute shower), we literally have to prime the water first. By that I mean I have to turn on the hot water, let it run for a couple of minutes, then turn it off and wait 20 minutes. Then when we go to use the hot water again we'll get hot water for a respectable amount of time. Now I am fairly ignorant to all this, but it seems a 71 gallon hot water heater should be capable of holding enough water to not need to be primed like this. I should be able to take a 30 minute shower, let alone 10 without running out. My shower this morning was decently warm for maybe 2 minutes before it was just warm-ish.   So if anyone can give me some ideas on what might be going on I would appreciate it. We've just put up with this for some years assuming perhaps it was some eco friendly thing. Like the system doesn't maintain much hot water in the tank so it's not always running and only heats water up when you start to use it? I hope that isn't the case though and even so, I should be able to get more hot water out of it. Any help?  UPDATE Sorry everyone, I meant to tell you all that the water heater was gas. The pilot light is lit. I don't recall the specific model though I can look that up if people think it will help. I have actually turned up the thermostat on it above the default and when the water heater is putting out hot water, it can be very hot. Too hot. But again, that requires us to prime it before we get any decent amount of hot water out.  UPDATE 2 Looked it up, I believe this is the model info if that helps anyone: State Select: High Output. Model number: GS675XRRS 300


having to chown chuck ttyUSB0    on each boot so that programs can access ttyUSB0    they don't work without the chown, how can i make the ownership stay as chuck or whatever on reboots, shut downs etc.

Since I updated from Ubuntu 10.04 (Lucid Lynx) to Ubuntu 12.04 (Precise Pangolin), I am unable to access the device connected in /ttyUSB0 if I don't have root access.  To be more specific, I use a USB-to-serial com port converter to access and configure Cisco equipment with software called . It happens that, since I upgraded to 12.04, PuTTY only sees the connected device when I run it as gksudo putty. If not, it says "unable to connect to port /ttyUSB0".  I have managed to change the permissions via chmod 666, and it works, but if I disconnect the USB device and reconnect, it goes back to root only. How do I permanently allow non-root access? I have a clue it might be via  rules, but I have no idea how to do it.  Obs.: Manufacturer and drivers are "PROLIFIC"


Are there any circumstances in which the terms 'moral' and 'ethical' can be used interchangeably?

I am currently writing an essay on artificial moral agents, and I need to explain the difference between ethics and morals. However, I am finding it really hard to find a good book or research paper which contains a citable definition.   Could someone point me in the right direction?


Long Story Short... my Database server died a month ago. I restored everything but the MSDB as the tape backup failed. I reconstructed some jobs but some essential ones are missing. I finally found the MSDB backup in an old partition, but here's the gist... it isn't a .BAK file but the actual database and log. I already created a new Database in my instance and attached the MSDB (with different name obviously, MSDBJobs) but I have no idea whatsoever on how can I extract the jobs from this database. I don't want to replace the current ones as some are new and essential as well. Thanks for any help provided :)

I had a MSSQL (MSSQL 2008 R2) cluster that failed in a way that I couldn't bring it back up (long story, servers ended up in BSOD loops, I'm blaming Broadcom and myself).   I've SQL backups, and even better, I've got the detached MDF and LDF files as they were on the SAN before everything went wrong. I've now got the task of restoring these back to a newly built server.   The databases themselves, logins and SSIS packages aren't a problem, as I've got all these. The thing that's bothering me is the SQL Agent jobs that were defined on the previous server. I'm dimly aware that these are stored in MSDB somewhere, but what steps should I go through to retreive these from the MDF/LDF files I've already got and load them on the new server?  I'm not going to be restoring the modal, msdb, master and temp databases on the new server, so should I be looking to attach the old files under different names and pull job definitions out of them, or is there some other (better) way?


I have a STM32WB55CGU6 where I have all my ADC pins used up and im trying to obtain the battery level using a pin which does not have a ADC (PB6) which is branched as shown in the picture:    This follows the principle where it will charge and discharge  following this link :   This is my current program but somehow it doesnt work and im pretty sure im doing something wronf but what I am not too sure.  while(1){       HAL_GPIO_WritePin(GPIOB, GPIO_PIN_6, GPIO_PIN_SET);        HAL_Delay(1);       HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_6);       while(HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_6)==1){           time++;       }       if (HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_6)==0){value = time;} }   Im programming with STMCubeIDE where I have set the pin to GPIO_Analog

I have a voltage divisor to measure the voltage of my battery which serves as a battery level detector and it is connected to a GPIO pin in a microcontroller which does not have an ADC. Is it possible to obtain the analog value? And if not is there another way to obtain the value without an ADC?  I have seen a way that will compare the voltage of the Vref of my microcontroller. Is it possible this way?  For the MCU, im using a STM32WB55CGU6 and the pin used is the PB6 (pin 46)


Let $A$ be an $n \times n$ matrix such that $A^2 = I$ and $A \neq I$. Show that $A$ is diagonalizable.   So far I tried multiplying both sides of the first equation by $P$ and by $P^{-1}$, but I don't know how to proceed from there.

Let $A$ be a square matrix of order $n$ such that $A^2 = I$.  Prove that if $1$ is the only eigenvalue of $A$, then $A = I$. Prove that $A$ is diagonalizable.   For  (1), I know that there are two eigenvalues which are $1$ and $-1$, how do I go about proving what the question asks me?


Can anyone give me a list of books to study so that I can "master" (whatever the precise definition of that may be) all the branches of physics? I want to start from the most elementary to the most advanced.

Every once in a while, we get a question asking for a book or other educational reference on a particular topic at a particular level. This is a meta-question that collects all those links together. If you're looking for book recommendations, this is probably the place to start.  All the questions linked below, as well as others which deal with more specialized books, can be found under the tag  (formerly ).  If you have a question to add, please edit it in. However, make sure of a few things first:   The question should be tagged  It should be of the form "What are good books to learn/study [subject] at [level]?" It shouldn't duplicate a topic and level that's already on the list   Related Meta:


The typical first application of Lagrange's equation is showing that it implies Newton's law for a particle whose Lagrangian is $L=\frac{1}{2}mv^2-V(x)$.  Plugging this Lagrangian into Lagrange's equation, we have that  $$\frac{\partial}{\partial x}\left(\frac{1}{2}mv^2-V(x)\right)=\frac{d}{dt}\frac{\partial}{\partial v}\left(\frac{1}{2}mv^2-V(x)\right)$$  Typically at this point books will conclude that, therefore, we must have Newton's 2nd law  $$-\frac{dV}{dx}=m\frac{dv}{dt}.$$  However, how can we be sure of the following?   $$\frac{\partial}{\partial x} \frac{1}{2}mv^2+\frac{d}{dt}\frac{\partial}{\partial v}V=0$$  The above result of Newton's law seems to depend on this, but I'm not sure how to go about showing that the last equation is true.

In the calculus of variations, particularly Lagrangian mechanics, people often say we vary the position and the velocity independently. But velocity is the derivative of position, so how can you treat them as independent variables?


Which one of each is correct?    A1 - He asked a simple question about the use of articles. vs A2 - He asked a simple question about use of articles.    B1 - All universities in Vancouver are amazing.  vs B2 - All of the universities in Vancouver are amazing.

Is there any difference between "all X", "all of the X", "all the X"? E.g.,        all friends   all of the friends   all the friends


Let $f$ : $\mathbb C \to \mathbb C$ be analytic such that $|Re(f(z)) Im(f(z))|$ $\le$ $1$ for every $z \in \mathbb C$. Show that $f$ is constant.   I know the set is bounded hence I should be able to apply Liouville Thm.   Other than this information I do not know how to approach this question.   Any help will be appreciated.

Let $f: \mathbb C \to \mathbb C$ be an analytic function, such that for all $z\in\mathbb C$, $$| \operatorname{Re}(f(z))\operatorname{Im}(f(z)) | \le 1.$$   I have to show that $f$ is constant.   I don't know how to apply Liouville's theorem to the question, but I can tell it is bounded, thus the theorem should apply. Any help would be appreciated.


I need a little help with a query I'm trying to run.  Basically I have two columns (trying to keep it simple) and I need to merge and concat These two columns are created from different tables with the following query:  select tmatter, tkinitb    FROM timecard, timekeep, matter   where ttk = tkinit   and mstatus = 'OP'   group by tkinitb, tmatter   order by tmatter ASC  tmatter  | tkinitb 1        |   A 1        |   B 2        |   C 2        |   D   I'm looking to have the results like this:  tmatter  | tkinitb 1        | A, B 2        | C, D   I'm not sure how to merge the different cells on the like cells.  Any help would be greatly appreciated.

I'm trying to migrate a MySQL-based app over to Microsoft SQL Server 2005 (not by choice, but that's life).  In the original app, we used almost entirely ANSI-SQL compliant statements, with one significant exception -- we used MySQL's group_concat function fairly frequently.  group_concat, by the way, does this: given a table of, say, employee names and projects...  SELECT empName, projID FROM project_members;   returns:  ANDY   |  A100 ANDY   |  B391 ANDY   |  X010 TOM    |  A100 TOM    |  A510   ... and here's what you get with group_concat:  SELECT      empName, group_concat(projID SEPARATOR ' / ')  FROM      project_members  GROUP BY      empName;   returns:  ANDY   |  A100 / B391 / X010 TOM    |  A100 / A510   So what I'd like to know is: Is it possible to write, say, a user-defined function in SQL Server which emulates the functionality of group_concat?   I have almost no experience using UDFs, stored procedures, or anything like that, just straight-up SQL, so please err on the side of too much explanation :)


I need your help, can anyone tells me that what this part of code is doing?  if line[-6:] == '[edit]':             state = line[:-6]   and   town = line[:(line.index('(')-1)]   the whole code is :     def get_list_of_university_towns():     '''Returns a DataFrame of towns and the states they are in from the      university_towns.txt list. The format of the DataFrame should be:     DataFrame( [ ["Michigan", "Ann Arbor"], ["Michigan", "Yipsilanti"] ],      columns=["State", "RegionName"]  )      The following cleaning needs to be done:      1. For "State", removing characters from "[" to the end.     2. For "RegionName", when applicable, removing every character from " (" to the end.     3. Depending on how you read the data, you may need to remove newline character '\n'. '''              with open('university_towns.txt') as file:         data = []         for line in file:             data.append(line[:-1])  #     print(data)     state_town = []     for line in data:         if line[-6:] == '[edit]':             state = line[:-6] #             print(state)         elif '(' in line:             town = line[:(line.index('(')-1)] #             print(town)             state_town.append([state,town])         else:             town = line.rstrip()             state_town.append([state,town]) #     print(state_town)     ans = pd.DataFrame(state_town, columns = ['State','RegionName'])      return ans get_list_of_university_towns()

I need a good explanation (references are a plus) on Python's slice notation.   To me, this notation needs a bit of picking up.   It looks extremely powerful, but I haven't quite got my head around it.


I'm still very new to Ubuntu, and I have it running on two computers. On the first computer, I was able to install and run steam no problem. I'm running Ubuntu 16.04 on both of them. Steam is installed on the other one, steam will install in the Ubuntu Software program, but when I try to run it, the icon will flash on the sidebar for about 15 seconds, then disappear. Steam will still appear in the system monitor. I have been killing the process before I try to restart steam with other methods.  I tried uninstalling and reinstalling and restarting my computer.   I tried running this code from  to see if that would fix it (it didn't.)  rm ~/.steam/steam/ubuntu12_32/steam-runtime/i386/usr/lib/i386-linux-gnu/libstdc++.so.6   I was able to get it to launch using this   LD_PRELOAD='/usr/$LIB/libstdc++.so.6 /usr/$LIB/libgcc_s.so.1 /usr/$LIB/libxcb.so.1 /usr/$LIB/libgpg-error.so' steam   from .   and also this   LD_PRELOAD='/usr/$LIB/libstdc++.so.6' DISPLAY=:0 steam   from   It runs, but when I restart it I have to use the same code again, it will not launch from the icon in the menu.   I followed the directions from  to try to change the desktop to automatically do the command line but it did not work. I changed the line to   bash -c "LD_PRELOAD='/usr/$LIB/libstdc++.so.6' DISPLAY=:0 steam"    and that seemed to work for the icon in the computer menu.  I think there should be a better way to do this, and if there is, I would dearly like to know. Is there a better way to do this? Is this a reasonable and acceptable solution, will this harm my computer in any way? I am also new to this site, this is only my second question I've ever asked, so if this question is in some way inappropriate, please be nice and let me know.  When I type steam in the terminal, I get the following:   Running Steam on ubuntu 16.04 64-bit STEAM_RUNTIME is enabled automatically /bin/bash: /home/banannakat/.local/share/Steam/ubuntu12_32/steam-runtime/amd64/lib/x86_64-linux-gnu/libtinfo.so.5: no version information available (required by /bin/bash)  grep: symbol lookup error: grep: undefined symbol: pcre_jit_stack_alloc grep: symbol lookup error: grep: undefined symbol: pcre_jit_stack_alloc awk: /home/banannakat/.local/share/Steam/ubuntu12_32/steam-runtime/amd64/lib/x86_64-linux-gnu/libtinfo.so.5: no version information available (required by /lib/x86_64-linux-gnu/libreadline.so.6) grep: symbol lookup error: grep: undefined symbol: pcre_jit_stack_alloc Installing breakpad exception handler for appid(steam)/version(1476379980) libGL error: unable to load driver: r600_dri.so libGL error: driver pointer missing libGL error: failed to load driver: r600 libGL error: unable to load driver: swrast_dri.so libGL error: failed to load driver: swrast

Actually I have installed the new Ubuntu 15.04 64bit, and when I'm trying to install Steam on it, there is a problem. In fact I have downloaded the deb package from steam website, installed it and when I start it nothing happens. I tried to start it from terminal and what I've got  $ steam Running Steam on ubuntu 15.04 64-bit STEAM_RUNTIME is enabled automatically Installing breakpad exception handler for appid(steam)/version(0_client) libGL error: unable to load driver: r600_dri.so libGL error: driver pointer missing libGL error: failed to load driver: r600 libGL error: unable to load driver: swrast_dri.so libGL error: failed to load driver: swrast


i started to learn a bit more about c++ and lately i see really often stuff like (DWORD)(x+y);  example:      int number = 10; int pointer;  pointer = *(int*)(number);  std::cout << "number: " << number << std::endl; std::cout << "pointer: " << pointer << std::endl;  getchar();   this makes a exception, i know, but could someone properly explain those action to me? like (int) and (DWORD) etc.. or, recommend me a book? thanks!

I've been writing C and C++ code for almost twenty years, but there's one aspect of these languages that I've never really understood. I've obviously used regular casts i.e.  MyClass *m = (MyClass *)ptr;   all over the place, but there seem to be two other types of casts, and I don't know the difference. What's the difference between the following lines of code?  MyClass *m = (MyClass *)ptr; MyClass *m = static_cast<MyClass *>(ptr); MyClass *m = dynamic_cast<MyClass *>(ptr);


Well, my first question is related to the energy of the capacitor. Why does the energy of capacitor equals $E=\frac{1}{2}QV$ and not $E=QV$;in other words, why we multiplied it by $\frac{1}{2}$?? My second question is why the sum of the voltage of each of the capacitors connected in series equals to that of the battery??

The maximum energy stored by a capacitor is when it’s (theoretically) fully charged, or just before it reaches dielectric breakdown, if you will. It seems, then, that the maximum energy ($E$) $=QV$, where $Q$ is the maximum charge attained and $V$ is the maximum ‘voltage’. However, the correct equation for the maximum energy is $E=\frac{1}{2}QV$. Why? I’m looking for a simple, intuitive explanation because my reasoning that $E=QV$ seems sound to me. I know about , but I’m looking for a reason to disprove my specific argument that $E=QV$ and not the “Oh, it comes from integration.” response.


Can I say, "He is the only person that I know."?  Are there rules about using that to describe people?

I came across this :     Unbelievable as it may seem, many individuals that fought in the   American Revolution were still alive in 1839, the year the world was introduced to photography. (choose the error - the 'answer' is in bold)   It noted that the reason "that fought" is wrong is that 'The relative pronoun “that” may not be used to refer to people (“individuals”) and should be replaced with the relative pronoun “who.”'   I had thought that the word "that" could refer to both people and objects (while which was reserved for objects and who reserved for people). Am I wrong?


Prove the following statement first by using formulas and second by using a counting argument. $$ \binom{n}{k}\binom{n-k}{j} = \binom{n}{j}\binom{n-j}{k} $$

I am looking for an intuitive explanation for the identity:  $$\binom{n}{h}\binom{n-h}{k} = \binom{n}{k}\binom{n-k}{h}$$  Thanks!


Ok so I have the steel smithing perk in blacksmith. I've upgraded a scimitar to superior. It will not go any higher at the moment. Is there a skill I can get to upgrade it past superior or will it stay that way?

Instead of only smithing weapons to exquisite, how I can smith better weapons? I have tried to use the weapon smithing skills constantly but I just can't figure it out.


I am using Ubuntu since last 2 years but still I couldnt find better way to install Ubuntu packages offline. As each package needs multiple dependencies its harder to find & get all the required dependencies.

I have a friend who has got a computer that is not connected to the Internet. Is there any way to install software offline easily?


A group of Humans as part of their survival training are dropped on the surface of a planet. They are supposed to be picked up after a few weeks, this doesn't happen. They eventually discover that the reason is a Nova.

I would love to identify a sci-fi novel I read in the late 60s or 70s.  It followed a group of young space cadets through their training in the Space Academy.  The training culminated in small groups of cadets being sent through a gateway in the space station, into different worlds where they had to survive whatever conditions they met beyond the gateway, as part of their training.  One such trip went wrong and the group ended up stranded in a hostile world for days, hoping to be rescued by their trainers.  I can't remember much about the story or protagonists so this may be too vague, but I remember descriptions of a vast space station hall and these young cadets bringing whatever kit they hoped they might need - some brought breathing apparatus and full survival gear, but others came with very little as they believed they would not be sent into conditions where they could die without the right equipment.  They hadn't bargained for the power surge or whatever it was that misdirected them as they passed through the gateway!  I also remember rivalry between the cadets - I think the hero was male and quietly heading for top cadet of the year award... and I think at least one of the group died in the unknown planet before they were rescued.  Does this ring a bell with anyone?  I remember the mood and tension more than the details but it was a long time ago!  I have a 10-year old son who I think would love this kind of story.  If anyone can help you have my thanks!


I am coming from a functional-programming background at the moment, so forgive me if I do not understand closures in C#.  I have the following code to dynamically generate Buttons that get anonymous event handlers:  for (int i = 0; i < 7; i++) {     Button newButton = new Button();      newButton.Text = "Click me!";      newButton.Click += delegate(Object sender, EventArgs e)     {         MessageBox.Show("I am button number " + i);     };      this.Controls.Add(newButton); }   I expected the text "I am button number " + i to be closed with the value of i at that iteration of the for loop.  However, when I actually run the program, every Button says I am button number 7.  What am I missing? I am using VS2005.  Edit: So I guess my next question is, how do I capture the value?

I met an interesting issue about C#. I have code like below.  List<Func<int>> actions = new List<Func<int>>();  int variable = 0; while (variable < 5) {     actions.Add(() => variable * 2);     ++ variable; }  foreach (var act in actions) {     Console.WriteLine(act.Invoke()); }   I expect it to output 0, 2, 4, 6, 8. However, it actually outputs five 10s.  It seems that it is due to all actions referring to one captured variable. As a result, when they get invoked, they all have same output.  Is there a way to work round this limit to have each action instance have its own captured variable?


For example, suppose we have a string:  'abcdefg'   And we need to get a list like this:  ['ab', 'bc', 'cd', 'de', 'ef', 'fg']   we should not use any kind of library  Here is my solution:  def str_split(s):     s = iter(s)     ch1=''     ch2=''     chars_list=[]     while True:         try:             ch1 = ch2 or next(s)             ch2 = next(s)             chars_list.append(ch1 + ch2)         except:             break     return chars_list   I wonder is there a better solution? Maybe it is possible to use list comprehension like ?

I have a list of arbitrary length, and I need to split it up into equal size chunks and operate on it. There are some obvious ways to do this, like keeping a counter and two lists, and when the second list fills up, add it to the first list and empty the second list for the next round of data, but this is potentially extremely expensive.  I was wondering if anyone had a good solution to this for lists of any length, e.g. using generators.  I was looking for something useful in itertools but I couldn't find anything obviously useful. Might've missed it, though.  Related question:


I've tried researching and I cannot find any explanation for this. About 2 weeks after Android 6 was released I did get a security update for lollipop but nothing since then. Everyone I know with a Nexus 5 has it, but I don't know anyone with a Nexus 6 besides myself. Why is my Nexus 6 not getting updated?  My phone is unlocked, but I do use T-Mobile.  Thanks

Android "M" was officially announced on at the Google I/O conference on May 28, 2015 and revealed to be 6.0 Marshmallow on August 17, 2015.  You can review the high-level changes at the  and the announcement on the official .  Of course, not all devices will get this update right away and others won't get it at all. Each manufacturer and carrier often choose to add their custom modifications which tend to delay the official release.  When will each device get Android 6.0, either officially or unofficially, if ever?  See also:


There are some urls like http://domain.com/user/:username and http://domain.com/post/:id on my website, the username and id is the parameter from database. I try to let google crawler more efficiently , can I use google webmaster tools > URL Parameters > add parameter ? I read the document but still don't get it how to set up? the column Parameter and the rest what should I filled? or this tools only for get method parameter?


I need to create a user which can SSH to a server, but can not run any commands or view anything, for the purposes of tunneling the connection without risk of revealing credentials. How do I do this? I looked on google but found no sources.  Edit: Would it also be possible to show a certain message to the user upon login? Instead of the usual 'Last logged in from xxx at yyy'?

How can I restrict a user on the SSH server to allow them only the privileges for ? i.e. So they cannot run commands even if they log in via SSH.  My Linux servers are Ubuntu 11.04 and OpenWrt.


I want signal strength information when pppd connection is already running. I am running pppd on embedded Linux environment and 3g modem manufactured Cinterion.  I knew commands from which i am able to know signal strength but when my pppd connection is running it will block /dev/ttyUSB and because of that i am not able to find signal strength information.  Need further more information please tell me.  Thanks in Advance, Ravi Bhuva.

I have a zte 3g modem. I use carrier provided dialer for connection establishment. Once the ppp connection is active, i would like to send some AT commands(for ex. Query signal strength, AT+CSQ). But the dialer i use locks the /dev/ttyUSB0 port, which is the command port to send AT commands for my modem. So is there any way, to send the commands, once the connection is active?    Edit: I also tried the additional port /dev/ttyUSB1. But the port is flowing with random data from the modem. A sample is given below.  T^PREFMODE??                                                                     ^PREFMODE:8                                                                       OK                                                                               TC                                                                               ^DSDORMANT:1                                                                      +CSQ:19, 99                                                                       OK                                                                               T^SYSINFO                                                                        ^SYSINFO:2,3,0,4,255                                                              OK                                                                               TT^SYSINFO?                                                                      ^SYSINFO:2,3,0,4,255     I tried adding my commands, i even got output. But the response is very poor. Most of the times, my AT commands went unnoticed.


Let $K$ be a splitting field of a polynomial over $\mathbb{Q}$. Suppose $K$ contains an $n$th root of some number $a$. Then how can we show that $K$ contains all the $n$th roots of unity?  I don't really see any relation between $\sqrt[n]{a}$ and the $n$th roots of unity. Knowing that the former is in $K$ doesn't seem to imply anything about the latter.

This statement is suggested as a correction to :  If $K$ is the splitting field of the polynomial $P(x)=x^n-a$ over $\mathbb{Q}$, prove that $K$ contains all the $n$th roots of unity.  How to prove it?


In Lagrangian dynamics, when using the Lagrangian thus:  $$ \frac{d}{dt}(\frac{\partial \mathcal{L} }{\partial \dot{q_j}})- \frac{\partial \mathcal{L} }{\partial q_j} = 0 $$  often we get terms such as the one below which result in zero:  example 1: $$ \frac{\partial \dot{q}}{\partial q} = 0 $$ example 2: $$ \frac{\partial q}{\partial \dot{q}} = 0 $$  I wasn't sure why but this is the closest I have come to reasoning it out:  $$ \frac{\partial \dot{q}}{\partial q} =  \frac{\partial \dot{q}}{\partial t}\frac{\partial t}{\partial q}  = 0 $$  because  $$ \frac{\partial t}{\partial q} = 0 $$  and similar for example 2. Is this correct?

Let us consider a particle in one spatial dimension $x$ and one temporal dimension $t$. Its Lagrangian $L$ is given by   \begin{eqnarray*} L &=& T- V \\   &=& \frac{1}{2} m\dot{x}^2 - V(x) \\   &=& L(x, \dot{x}) \end{eqnarray*}  But if I write $ L = \frac{1}{2} m [\frac{d}{dt}({x})]^2 - V(x)$, then it seems to me that $L$ depends only on $x$.   So, my question is why it is said that $L$ is a function of $x$ and its derivative $\dot{x}$ ?


UPDATE: They're still here. Help me stop or trap them! Hi SF'ers, I've just had someone hack one of my clients sites. They managed to get to change a file so that the checkout page on the site writes payment information to a text file. Fortunately or unfortunately they stuffed up, the had a typo in the code, which broke the site so I came to know about it straight away. I have some inkling as to how they managed to do this: My website CMS has a File upload area where you can upload images and files to be used within the website. The uploads are limited to 2 folders. I found two suspicious files in these folders and on examining the contents it looks like these files allow the hacker to view the server's filesystem and upload their own files, modify files and even change registry keys?! I've deleted some files, and changed passwords and am in the process of trying to secure the CMS and limit file uploads by extensions. Anything else you guys can suggest I do to try and find out more details about how they got in and what else I can do to prevent this in future?

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.


I have provided some sentences below. What's the difference between "if a" and "if any" in the sentences. I think all of them are correct and mean the same thing. I don't know what the difference is. I always use them interchangeably in this kind of context. Can someone please tell me how I should choose the correct word?  1- If a/any student is found smoking in the classroom, he or she will be suspended from the school.  2- As per the new tax law, If a/any house is situated in a metropolitan city, 15 percent tax will be charged on the value of it.

I didn't have an idea.      I did not have any idea.   I am much more familiar with the second one. The first one sounds a bit odd to me, but sounds fine if I say:     I did not have even an idea.   But, the first one is also one of the widely used sentences by natives. What is the difference between the two?


Sorry to ask a repetitive question.  I read and tried multiple solutions posted in last 3 to 4 hours but couldn't succeed. Bluetooth ON and visibility ON  but neither detect any device nor visible to other devices.  I 'm not good with Ubuntu, not even know that what exactly following commands do , can someone point me towards right direction  output of lsusb is  Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 003: ID 04f2:b52d Chicony Electronics Co., Ltd  Bus 001 Device 002: ID 0a5c:216d Broadcom Corp.  Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub   lspci -knn | grep Net -A2; lsusb  03:00.0 Network controller [0280]: Broadcom Corporation BCM43142 802.11b/g/n [14e4:4365] (rev 01)     Subsystem: Hewlett-Packard Company BCM43142 802.11b/g/n [103c:804a]     Kernel driver in use: wl Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 003: ID 04f2:b52d Chicony Electronics Co., Ltd  Bus 001 Device 002: ID 0a5c:216d Broadcom Corp.  Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub   output of     rfkill list   0: phy0: Wireless LAN     Soft blocked: no     Hard blocked: no 1: brcmwl-0: Wireless LAN     Soft blocked: no     Hard blocked: no 3: hci0: Bluetooth     Soft blocked: no     Hard blocked: no   For dkms status  bcmwl, 6.30.223.271+bdcom, 4.4.0-72-generic, x86_64: installed bcmwl, 6.30.223.271+bdcom, 4.4.0-75-generic, x86_64: installed bcmwl, 6.30.223.271+bdcom, 4.4.0-78-generic, x86_64: installed bcmwl, 6.30.223.271+bdcom, 4.4.0-79-generic, x86_64: installed bcmwl, 6.30.223.271+bdcom, 4.4.0-81-generic, x86_64: installed bcmwl, 6.30.223.271+bdcom, 4.4.0-83-generic, x86_64: installed   dmesg | grep -i blue  [   12.207904] Bluetooth: Core ver 2.21 [   12.207919] Bluetooth: HCI device and connection manager initialized [   12.207921] Bluetooth: HCI socket layer initialized [   12.207924] Bluetooth: L2CAP socket layer initialized [   12.207928] Bluetooth: SCO socket layer initialized [   12.541892] Bluetooth: hci0: BCM: chip id 70 [   12.557906] Bluetooth: hci0: faisal-HP-Notebook [   12.557910] Bluetooth: hci0: BCM (001.001.011) build 0000 [   12.709950] bluetooth hci0: Direct firmware load for brcm/BCM.hcd failed with error -2 [   12.709954] Bluetooth: hci0: BCM: Patch brcm/BCM.hcd not found [   14.711794] Bluetooth: hci0 command 0x1003 tx timeout [   21.446442] Bluetooth: BNEP (Ethernet Emulation) ver 1.3 [   21.446445] Bluetooth: BNEP filters: protocol multicast [   21.446448] Bluetooth: BNEP socket layer initialized [   58.953015] Bluetooth: RFCOMM TTY layer initialized [   58.953020] Bluetooth: RFCOMM socket layer initialized [   58.953024] Bluetooth: RFCOMM ver 1.11 [  538.154130] Bluetooth: hci0 command 0x1003 tx timeout [ 1088.482264] Bluetooth: hci0 urb ffff8802519c5cc0 failed to resubmit (2) [ 1101.185972] Bluetooth: hci0: BCM: chip id 70 [ 1101.201973] Bluetooth: hci0: faisal-HP-Notebook [ 1101.201977] Bluetooth: hci0: BCM (001.001.011) build 0000 [ 1101.201993] bluetooth hci0: Direct firmware load for brcm/BCM.hcd failed with error -2 [ 1101.201995] Bluetooth: hci0: BCM: Patch brcm/BCM.hcd not found [ 1103.205069] Bluetooth: hci0 command 0x1003 tx timeout

Bluetooth is on but can't find or be found by any other devices.  Output of sudo service bluetooth status:  ● bluetooth.service - Bluetooth service    Loaded: loaded (/lib/systemd/system/bluetooth.service; enabled; vendor preset: enabled)    Active: active (running) since ხუთ 2015-06-04 22:33:18 GET; 13min ago  Main PID: 26678 (bluetoothd)    CGroup: /system.slice/bluetooth.service            └─26678 /usr/sbin/bluetoothd -n  ივნ 04 22:39:14 Rangoo bluetoothd[26678]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/BlueZ4/HFPAG ივნ 04 22:39:14 Rangoo bluetoothd[26678]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/BlueZ4/HFPHS ივნ 04 22:39:14 Rangoo bluetoothd[26678]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/BlueZ4/A2DPSource ივნ 04 22:39:14 Rangoo bluetoothd[26678]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/BlueZ4/A2DPSink ივნ 04 22:39:14 Rangoo bluetoothd[26678]: bluetoothd[26678]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/BlueZ4/HFPAG ივნ 04 22:39:14 Rangoo bluetoothd[26678]: bluetoothd[26678]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/BlueZ4/HFPHS ივნ 04 22:39:14 Rangoo bluetoothd[26678]: bluetoothd[26678]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/BlueZ4/A2DPSource ივნ 04 22:39:14 Rangoo bluetoothd[26678]: bluetoothd[26678]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/BlueZ4/A2DPSink ივნ 04 22:39:14 Rangoo bluetoothd[26678]: Adapter /org/bluez/26678/hci0 has been enabled ივნ 04 22:39:14 Rangoo bluetoothd[26678]: bluetoothd[26678]: Adapter /org/bluez/26678/hci0 has been enabled   Output of lsusb:  Bus 003 Device 005: ID 0a5c:21d7 Broadcom Corp. BCM43142 Bluetooth 4.0   How can I fix it?


I have a git hub repository for hackerrank solutions which is ranking very well.  Here is the link-   My repository is ranking well if someone searches for hackerrank solutions but it's not ranking for files and folder which are present in the nested folder in the repository.   ex-   people are not able to find the solution for drawingbook.java  If anybody search drawingBook it's not ranking at all. Can anybody explain why and provide the solution for the same?  What I should do to rank my java programs?  Note: I really dont understand whether this question should be a part of seo or not because its related to git hub repository.

This is a general, community wiki  question and answer pair intended to address any questions   concerning the reasons a site or specific site contents do not appear   in search engine results.      If your question was closed as a duplicate of this question and you   feel that the information provided here does not provide a sufficient   answer, please open a discussion on .   My site (or specific pages on my site) is not appearing in search engine results.  Why isn't my content indexed and what can I do about it?


I have a raster and a vector point file. I need to generate another raster of same resolution showing how many points are inside the corresponding pixels of the original raster.  Something like that:   Is there a way of doing that in QGIS?   I just want the number of points, no attributes involved.

I have a point layer that shows the distribution of a species.   Is it possible in QGIS to convert this point layer to a raster grid in which the value of each cell corresponds with the amount of points within that cell?   Until now, I only managed to attach attribute values to the grid cells. I have already added a column in my attribute table that has the value '1' for each point, hoping that there is a way to use a sum of attributes for each grid cell.


While going through:  info coreutils 'dd invocation'   I came across:  dd if=/dev/zero of=/dev/null count=10MB & pid=$!   What is $! used for?

If I'm assigning a variable with  temp=$!   what would it be its value?


I'm currently running a mega dungeon in 5e D&D, and my players have recruited some monsters into their service. I have been building encounters using the dungeon masters guide rules (pg. 81-84), but these only account for groups of player characters. How should I recalculate the encounter difficulties that I have planned when they also have some recruited monsters with them?   Options I have considered are shifting the encounter multiplier  (pg. 82) according to the party size paragraph (pg. 83), but this fails to account for the inherent weakness of the recruited MOBs,   Alternatively, I could maybe add the modified experience total of the group of MOBs to the parties XP thresholds, as modified XP is probably a fairly accurate guage of additional party ability (probably without including them in the party size)  If anyone has done this before, knowing what worked would be nice, otherwise I'll use my best judgement and comment later on how well it worked out

Hypothetical party:  1st level human wizard (PC) 3x guard NPC 1x acolyte NPC    This is the player's first time, and it's a solo campaign. The first mini-adventure involves recovering the cargo of a supply caravan that didn't make it to her magic academy due to bandit hijacking (as a sort of graduate-test). The guards and healer are on contract from the school to assist her. The acolyte is essentially just to hang back and tend to wounds and probably won't engage in combat unless someone goes down or the PC is seriously wounded.  So, with that "party" makeup, how do I determine the XP budget for a "medium" or "hard" encounter since there's no clear CR->level mapping in 5e for those NPCs (who will certainly factor into any combat as meatshields and melee damage)? I was thinking about reverse-engineering them as crumby lvl2 fighters (given the 2 HD worth of HP they have), but they certainly aren't on par with a lvl2 fighter, given the lack of action surge, second wind, etc., so the encounters would end up being too hard compared to PCs or DMPCs.   Could they be lvl1-equivalents, essentially trading any abilities a PC would have for extra HP? How would this work at later levels with higher CR NPCs (veteran, priest, mage, etc.)? I'd rather not have to build a bunch of DMPCs as hirelings, because I want the NPCs to be a bit vanilla compared to the versatility of my player. I'm already introducing 1-2 DMPCs to the game for her to take control over as she gets a feel for the flow of the game (for now, she'll handle them out of combat, and I'll effectively show her how to utilize them until she's ready).     Just to be clear, I'm comfortable with the monster-generation rules for crafting NPCs as enemies to determine their CR, but I'm confused on how to use them in the adventuring party when budgeting encounter difficulty XP.


I'm a student at a University in the UK and in the summer coming up I've arranged to do a volunteer internship for a Charity for 10 weeks. They'll be offering me no remuneration what so ever and the type of work I'll be doing is administrative.   I'm wondering what type of travel permit I'll need, I've heard some people say WVP, I've heard some say I can work on an ESTA and I've heard some people say a B-1? the latter really confusing me because I thought you had to be in business for that aha.  Any help would be much appreciated, given that it's 10 weeks of work I'll be happy to be in and out of the USA within the usual 90 days (especially since I'll have my 3rd year or Uni to get back to) so if anyone has any advice what so ever I would be so appreciative!

I am going to Santa Monica for 4 weeks to polish my English in July and would like to volunteer at the Planetary Society located in Pasadena.  I am a Swiss citizen and have a biometric passport. However, I don't have any special visa, as there is no visa needed for the school I am attending and using the Visa Waiver Program, I am allowed to stay up to 90 days in the US.  Am I allowed to do volunteer work during my stay?


I can not find a clear explanation for when NOT to use Bessel's correction and use N instead of N-1.  As I understand it, Bessel's correction would apply to things such as clinical trials, sampling from a production line, voter polling, etc.  I am performing an experiment analyzing mass flow rate into 3 entry points.  I want to analyze the deviation of the distribution into those 3 entry points and compare it to an ideal perfectly even distribution of a (relatively) known mass.  I believe I know the "true population mean" in this circumstance - its an even distribution so if I reduce everything to percentages, it would be X = 1/3 = 0.333.  I believe I need to use N instead of N-1.  The complicating factors are that while I think I know the starting mass for the experiment, my scale has an instrument error associated with it.   Also my measurement of mass flow rate versus time has multiple measurement instruments associated with it as well!  I guess if I boil down the question.... I need to figure out if I need to use N or N-1 for standard deviation.  Does the error inherent to the measurements necessitate N-1 or does knowing my "ideal distribution" allow me to use N?

I was asked today in class why you divide the sum of square error by $n-1$ instead of with $n$, when calculating the standard deviation.  I said I am not going to answer it in class (since I didn't wanna go into unbiased estimators), but later I wondered - is there an intuitive explanation for this?!


How do I search for a hidden file in macOS?  I know the Command Shift . shows hidden file on Finder, but I am looking for a way to search for it.  For Example, I want to look for .npmrc file, and it does not find it in SpotLight nor in Finder Search

I am running Mac OS X 10.8 (Mountain Lion) and had to edit an invisible file as part of an Android project. While I eventually found it, Spotlight was of no help, since it could not find an invisible file when searching for the exact name (.classpath) and with the 'File Visibility' option set to 'Visible or Invisible'.  Why didn't Spotlight work in this instance?


I am running Ubuntu 14.04 32bit.   Recently, I decided to install ClamAV. It keeps warning me about this pua.win.trojan.xored-1. I read online that this means I have a rootkit.   I download and ran chkrootkit. It says the following:  The following suspicious files and directories were found:   /usr/lib/python2.7/dist-packages/PyQt4/uic/widget-plugins/.noinit  Searching for Suckit rootkit...  Warning: /sbin/init INFECTED   I just ran rkhunter and this came up:  /usr/bin/unhide.rb [ Warning ]   To remedy the problem, I am currently downloading a new Ubuntu ISO. I will re-install everything from scratch. Assuming that I have a rootkit, is this enough to solve the problem?    Update: I didn't know that rkhunter wasn't finished yet. Here is some more:  Checking /dev for suspicious file types                  [ Warning ] Checking for hidden files and directories                [ Warning ]

I recently ran chkrootkit and got the following line:  Searching for Suckit rootkit...                   Warning: /sbin/init INFECTED   What does this mean exactly? I heard this was a false positive, what is exactly happening.  Please and thank you.


The question is pretty straightforward:   The only Vulcans I ever saw on TNG were Spock and Sarek. Did any other Vulcans make any appearances? I know there was an effort to avoid Vulcan stories, but surely Picard and co. must have run into some other Vulcan besides Spock and his dad.

In the TNG episode , Worf ends up being the only viable donor available to save the life of an injured Romulan.      Crusher: "Worf, you are the only one who can save his life."   Worf: "Then he will die."   Surely a Vulcan would be a superior match for obtaining vital bodily fluids. And with a crew compliment of 1,014 members there wasn't a single Vulcan serving on the Enterprise-D?      Worf: "There is a substance within my cells which you need to survive."   Patahk: "Then you've come to hear me beg for my life?"   Worf: "No."   Patahk: "I would rather die than pollute my body with Klingon filth!"


I want to get data from table in 5 member groups. How can I get nth five records( The nth group). I mean the records between (n-1)*5 and (n)*5.   I do not like to find my records in this below form, cause every time it runs 2 queries in my machine.  SELECT MAX(Salary) as 'Salary' from EmployeeDetails where Salary NOT IN ( SELECT TOP n-1 (SALARY) from EmployeeDetails ORDER BY Salary Desc )   Note: I am new in Oracle and just asking you to give me a hint about this and not asking a complete code.

Is there a way to make an Oracle query behave like it contains a MySQL limit clause? In MySQL, I can do this: select *  from sometable order by name limit 20,10  to get the 21st to the 30th rows (skip the first 20, give the next 10). The rows are selected after the order by, so it really starts on the 20th name alphabetically. In Oracle, the only thing people mention is the rownum pseudo-column, but it is evaluated before order by, which means this: select *  from sometable where rownum <= 10 order by name  will return a random set of ten rows ordered by name, which is not usually what I want. It also doesn't allow for specifying an offset.


So, there's this picture   Floating around on the internet for the standard model of physics in a relatively short form. I want to typeset this in LaTeX in order to print it. However, I can't find a way to typeset the crossed out D in the second line.  So far, I have this      \documentclass[a4paper,10pt]{scrartcl}       \usepackage{amsmath,amssymb}      \begin{document}     What part of      \begin{align*}     \mathcal{L} &= - \frac{1}{4} F_{\mu \nu} F^{\mu \nu} \\         &+ i \bar{\psi} D \psi + h.c. \\         &+ \bar{\psi}_i y_{ij} \psi_j \phi + h.c. \\         &+ |D_\mu \phi|^2 - V(\phi)     \end{align*}      didn't you understand?      \end{document}

How can I strike through an expression (e.g. "2x") obliquely, e.g. from bottom left to top right, so as to indicate cancellation? With the \sout command from the ulem package, I can only strike horizontally.


I have a generic method, so:  public void Export<T>(List<T> exportList, string filePath, byte fileType) where T: class   There are two possibilities for <T>: <Category> and <ProductSupplier>.  I don't know which one I am using in a given runtime instance; which one to use is passed as a parameter to the method calling this method.  Is it possible to pass a variable value to <T> during runtime? I've played around with GetMethod/Invoke, etc. (I've already gotten that to work with a non-generic method), but they seem to address the method itself, rather than working as a mechanism to vary the generic List type.  [Edit]As it turns out, my question has its basis in a misunderstanding.  When I first got my Export method to work at all, it was with this format:   public void Export<Category>(someCategoryList, "C:\Temp2\myFile.txt", 0)    I wanted to know how I could plug different values in for <Category> without explicitly doing so at design time with some sort of ever-expanding switch statement.  As it turns out, this works fine:  public void Export(someCategoryList, "C:\Temp2\myFile.txt", 0)    so the problem is moot.  I've already been able to derive the right List ("someCategoryList" in my example) using Reflection, so problem solved.

What's the best way to call a generic method when the type parameter isn't known at compile time, but instead is obtained dynamically at runtime?  Consider the following sample code - inside the Example() method, what's the most concise way to invoke GenericMethod<T>() using the Type stored in the myType variable?  public class Sample {     public void Example(string typeName)     {         Type myType = FindType(typeName);          // What goes here to call GenericMethod<T>()?         GenericMethod<myType>(); // This doesn't work          // What changes to call StaticMethod<T>()?         Sample.StaticMethod<myType>(); // This also doesn't work     }      public void GenericMethod<T>()     {         // ...     }      public static void StaticMethod<T>()     {         //...     } }