I have a laptop with windows installed in 1TB hdd. I recently bought a new 256GB SSD(Gammix S5) and I installed ubuntu on it (I haven't allocated this to windows so only Ubuntu is present in it). So I have installed ubuntu only on the SSD and the installation process was successful. It asked me to restart and then remove the installation medium and I did so. Now it restarts and only boots to windows and it doesn't let me choose which OS to boot into (The grub screen doesn't show up).

I installed Ubuntu on a Dell XPS 13 laptop that had Windows 10 preinstalled on it. I installed it from a USB flash drive on a partition. When I boot my computer I can only boot into Windows 10 and Ubuntu is nowhere to be seen.  If I boot into my USB then I can see that Ubuntu is installed, but I can't get to it from the BIOS boot menu.


If $A,B$ are two PSD matrices, will $AB$ also be PSD?

I see on Wikipedia that the product of two commuting symmetric positive definite matrices is also positive definite. Does the same result hold for the product of two positive semidefinite matrices?  My proof of the positive definite case falls apart for the semidefinite case because of the possibility of division by zero...


i'm new to django.  In django i want to call  my function automatically for every 3 hours.  Is there any way to do it? or any packages is there for do this job?  thanks

I've been working on a web app using Django, and I'm curious if there is a way to schedule a job to run periodically.   Basically I just want to run through the database and make some calculations/updates on an automatic, regular basis, but I can't seem to find any documentation on doing this.  Does anyone know how to set this up?  To clarify:  I know I can set up a cron job to do this, but I'm curious if there is some feature in Django that provides this functionality.   I'd like people to be able to deploy this app themselves without having to do much config (preferably zero).  I've considered triggering these actions "retroactively" by simply checking if a job should have been run since the last time a request was sent to the site, but I'm hoping for something a bit cleaner.


Is ssd drives a good medium for long term backup storage? say i filled an ssd and stored it in some dark drye place, how long would it last? if not, which medium has the best shelf life for long term storage? flash drives, ssd, harddrives, optical tape etc...?

This question was inspired by . There have been other similar questions, but none with the same criteria.  This is two questions in one.   How do you store financial/critical records that should survive anything but a fire and should be available for decades? Lets say I want to store family photos/videos and want people do be able to find them in storage 100 years from now and still be able to use them. How would this be done?   Criteria   Long term means 30+ years guaranteed. 100+ years average. [If this is not practical, use the closest solution] High volume means a couple terabytes. Answers can be 'no-compromise/industrial' solutions or practical solutions for the home office/small business user. Media will not be active during the timespan. (i.e., if you suggest hard drives, they will not be spinning).  Further, there is no expectation of needing to read these archives. They are there for emergency or "for future generations" purposes. Should not require maintenance (if at all possible).    My thoughts:   CD-R/DVD-Rs have proven to me, even in the short term, to be a terrible medium for backups. They seem to be very fragile and seem to lose their data a very short time even when in pristine condition. I can't help but think that storing data on a couple of 1TB hdd's and then expecting them to spin up correctly a decade or two later to be a terrible idea. Am I wrong? Industrial tape drives seem like a viable option?


I've learned that a geodesic maximizes its proper time in Minkowski spacetime. Is this still true in general curved spacetime?  In other words, does the geodesic equation give the globally extremal path from one point in spacetime to another. Assuming the points are time-like separated.  I would think that by the local equivalence theorem, the geodesic equation gives a locally extremal path. Can it proven to be globally extremal?

In classical General Relativity (meaning not modified) one can think of geodesics in two ways.    One way is to say that a geodesic is the curve which is the straightest (in analogy with the flat case) among all curves. More or less the story goes like this (correct me if I'm wrong): in the flat case geodesics are of the form $x^\mu(s)=st^\mu +b^\mu$ where $t$ and $b$ are constant vectors and $s$ is the curve parameter. The curve tangent vector is $\frac{dx^\mu}{ds}=t=const$ so $$\frac{dt^\mu}{ds}=t^\nu\partial_\nu t^\mu=0.$$ This is a tensor equation and by general covariance it  holds true in a general spacetime, mutatis mutandis: $$t^\nu\nabla_\nu t^\mu=0.$$ Another way is to obtain the equation by finding the minimum of the length functional $$L=\int \sqrt{g(t,t)} \,\, d\tau,$$ we get $$\frac{dt^\mu}{d\tau}+\Gamma^\mu_{\alpha\beta}t^\alpha t^\beta=0.$$ The above equation turns out to be just $t^\nu\nabla_\nu t^\mu=0$, with a certain parametrization choice.    The two formulations are thus equivalent. My question is when and why is it so? Is there a deep reason?  Looking up Wald's book I found the following, unclear to me, argument:     "On a manifold with a Riemannian metric, one can always find curves of arbitrarily long length connecting any two points. However, the length will be bounded from below, and the curve of shortest length connecting two points (assuming the lower bound in length is attained) is necessarily an extremum of length and thus a geodesic. Thus, the shortest path between two points is always a straightest possible path."    Later in the book he also says something about conjugate points.  I always thought it had to do with torsion: If we relax the condition $\Gamma^\mu_{\alpha\beta}-\Gamma^\mu_{\beta\alpha}=0$ then the connection is not Levi-Civita, hence $\delta_g L=0$ remains unchanged but $t^\nu\nabla_\nu t^\mu=0$ does and gives a different geodesic equation.. so Straightest $\neq$ Shortest anymore.  Can anyone clarify things to me?


I'm new to python and struggling with this question - Create a function which works as follows: d={1:"x",2:"y",3:"x",4:"z"}  invert_d(d) {"x":(1,3),"y":(2),"z":(4)}  So invert_d gives a new dict with the values of multiple keys as lists. I have to say, that I never worked with dicts and started python 1 week ago...so I'm a total newb. I am new to python.... and I'm struggling with this question: Edit: I read wrong and fixed the Dict. Sorry guys :( Also we cant import in the exam

Given a dictionary like so:  my_map = {'a': 1, 'b': 2}   How can one invert this map to get:  inv_map = {1: 'a', 2: 'b'}


What is the difference in results between:   RIGHT JOIN and RIGHT OUTER JOIN  LEFT JOIN and LEFT OUTER JOIN ?   Can you please explain it through some examples?

What is the difference between LEFT JOIN and LEFT OUTER JOIN?


I have a script that opens terminal and list directories. My problem is that the second terminal ls the files but disapears in a flash. how can i make it not disappear? i have tried sleep but not working.

I have a script in file bla.sh and it is executable. When I click on it, the script is executed and the window is closed. I'd like the window to stay open.  Something like command cmd /k** command in Windows.  P.S. I don't want to use pause, but I want to able to write more commands after the script was executed.


Well, I have a Linux virtual machine running in my vmWare. And I would actually love to use my Linux in Windows Power Shell. So I usually use it by doing an SSH to my VM. Recently I came across the "Windows Power Shell ISE" where you can have the feature of opening multiple tabs and other cool stuff.  Here comes the actual problem, when I try to do SSH to my virtual machine, the SSH Operation is being stucked and it is not showing me any further console or message. I am having an SSH Client that comes with GIT, Windows 8.1 and vmWare Workstation 10.  PS C:\> ssh esis@192.168.255.142 ssh : Warning: Permanently added '192.168.255.142' (RSA) to the list of known hosts. At line:1 char:1 + ssh esis@192.168.255.142 + ~~~~~~~~~~~~~~~~~~~~~~~~     + CategoryInfo          : NotSpecified: (Warning: Perman...of known hosts.:String) [], RemoteException     + FullyQualifiedErrorId : NativeCommandError

I have a Linux VM guest running in my vmWare host that I want to access using Windows PowerShell ISE. I normally can SSH to my VM, but I cannot with Windows PowerShell ISE.  When I try to do SSH to my virtual machine, the SSH Operation is gets stucked and will not show me any further console or message. I am using an SSH Client that comes with GIT, Windows 8.1 and vmWare Workstation 10.  PS C:\> ssh esis@192.168.255.142 ssh : Warning: Permanently added '192.168.255.142' (RSA) to the list of known hosts. At line:1 char:1 + ssh esis@192.168.255.142 + ~~~~~~~~~~~~~~~~~~~~~~~~     + CategoryInfo          : NotSpecified: (Warning: Perman...of known hosts.:String) [], RemoteException     + FullyQualifiedErrorId : NativeCommandError


We know that magnetic field is produced by a current carrying wire with time varying current? My doubt is that- do the electrons in motion cause the magnetic field or is it due to some another reason?

I'm tutoring high school students. I've always taught them that:     A charged particle moving without acceleration produces an electric as well as a magnetic field.   It produces an electric field because it's a charge particle. But when it is at rest, it doesn't produce a magnetic field. All of a sudden when it starts moving, it starts producing a magnetic field. Why? What happens to it when it starts moving? What makes it produce a magnetic field when it starts moving?


We know the following:  Two masses are attracted to one another, as represented by Newtonian gravity $F = \frac{GMm}{R^{2}}$  Light is massless and bends in the curvature of space-time which can be created by a mass, where the deflection is calculated with Einstein's general relativity and is twice that calculated by Newtonian gravity, .  $E = mc^{2}$, where m is the relativistic mass.   Is there something special about mass energy that produces a curvature of spacetime? If that rest mass energy were converted to light energy (say, by annihilation of an equally large amount of matter and anti-matter, a planet sized "anti-matter bomb"), would the spacetime curvature resulting from the originating mass essentially instantaneously disappear? The inverse process, say through a "pair-production bomb," could instantaneously create space-time curvature. Of course, "instantaneous" here is nearly achieved anyway since the light source is traveling at the speed of light toward the about-to-be-born mass. Of course, this also answers the question of whether light attracts itself (through "gravity").

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


Consider the following code:  char char_a = 'A'; int int_b = 34;  char* p_a = &char_a; int* p_b = &int_b;  cout<<"Value of int_b is (*p_b) :"<< *p_b<<endl; cout<<"Value of &int_b is (p_b) :"<< p_b<<endl;  cout<<"Value of char_a is (*p_a) :"<< *p_a<<endl; cout<<"Value of &char_a is (p_a) :"<< p_a<<endl;   When I run it, output is:    So why doesn't it show the address in the case of char pointer as it does for the integer's pointer?

I'm using C++ to understand how exactly pointers work. I have this piece of code using arrays, which I'm using just to understand how the equivalent works with pointers.  int main() {         int arr[10] = {1,2,3};         char arr2[10] = {'c','i','a','o','\0'};     cout << arr << endl;     cout << arr2 << endl; }   However when I run this, arr outputs the address of the first element of the array of ints (as expected) but arr2 doesn't output the address of the first element of the array of chars; it actually prints "ciao".  What is it that I'm missing or that I haven't learned yet about this?


I have tried using apex:iframe, but it displays a blank page using     apex:iframe  <apex:page showheader="true" sidebar="true">     <apex:iframe src="/01Z2w000000ooGVEAY/" height="600px" width="70%"/> </apex:page>                                                                                Then I had tried using wave:dashboard <apex:page showheader="true" sidebar="true">  <wave:dashboard dashboardId="01Z2w000000ooGVEAY"          showTitle="true"          height="800px"          openLinksInNewWindow="true" />             </apex:page>                                                                                The result was a blank page, for both cases

I want top display dashboard in VF page.    When I am trying to do it using  blank window appear.  <apex:iframe src="/01Z28000000Hdzo" >  Right now I am doing as per follows.  Page -   <script language='javascript'>         {!dashboardBlob} </script>   Controller -   public string getdashboardBlob()  {  PageReference dbPage = new PageReference('/01Z28000000Hdzo');  Blob pageBlob = dbPage.getContent();  return pageBlob.toString()   }    Using above Dashboard is loaded into page but when I am trying to refresh the dashboard by clicking Refresh button (Standard button present on Dashboard) it gives me Access Control Origin error.  "XMLHttpRequest cannot load . No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin '' is therefore not allowed access."   Please suggest if you have any solution for this.


Ancestry DNA results came back on my possible half sister. We're showing 1,329 cMs with 34 shared segments. All it indicated was we were "close relationship - 1st Cousins" Tracing indicates a good possibility we are half siblings. Is the 1,329 on Ancestry enough to establish our relation or should we submit DNA samples to a lab for their analysis?

My husband did ancestry dna to find any info on his biological fathers side.    He just got a “close family” match with whom they share 1440 cM across 49 segments.  Is it possible to be a half sibling?   Or more likely that is match is my husbands half nephew?    I don’t think the match is my husbands uncle only because of age but maybe possible.


I suspect these particles exist, but are extremely short-lived, even compared to other unstable, exotic particles...

Why do quarks tend to bond in groups of three?   I understand why they might in bond in groups of three to create a net charge of zero (i.e. neutrons), but I don't understand why they form protons and not, for example, commonly form in groups of four. I have done background research on this question, and did not find any information. The wikipedia article on baryons () was not helpful either.  To summarize, why are mesons and baryons more common than other hadrons?


as in "... enabled them to remember all the detail of the story."  All the details sounds much more natural to me, but I don't believe detail is necessarily incorrect.  Can someone elaborate/confirm? Thanks!

Which one is correct? "To have a keen eye for detail" or "To have a keen eye for details"?


Achievements list doesn't contain an icon for new privilege for both iOS and Android apps:     Web contains an icon either:    Is it possible to add same icon as in web?

Icons for privilege are not visible on mobile site as well as mobile app  (on Android). Android app    Mobile website


I've got an Ico sphere. First I marked the seam:   Then I Selected the whole thing and UV unwrapped:   However, when I go into the UV image editor, nothing comes up:   I'm using cycles

I created a very simple chair mesh and I would like to unwrap it so that I can map a texture. I would like to have Smart UV Project unwrap it automatically, but whether I do it that way or try manually, I am unable to unwrap the model.   Is there something I'm missing?    I tried a few guides, but I'm not sure where I'm going wrong.  My File:


Having yet again rejected a small edit[1] on a recently closed question because it will kill the OP's chances of it reaching a correct review to reopen, I wondered if it would be possible to inform editors if they attempt this.  for relevant background to this. Of course, in an ideal world, the more experienced reviewers will always reject the edits - but the editor will presumable never find out why. It's been a while since I was new enough to see what notification you might get on a review, whether successful, or otherwise, but as I recall it's nothing more than 2 points popping up in your score dock… or not, by which time you've probably forgotten. Perhaps for all editors, not just new users, who attempt an edit on a closed post within 5 days of its closure? Some notification along the lines of  "Any edit to a closed post will promote it to the Reopen Review queue; thus depriving the original author of the chance to have any relevant informational edit to their question reviewed for reopening. Closed, edited posts only have one chance to be reviewed for reopening."  My wording could probably be improved [1] An otherwise perfectly acceptable edit, which would have raised the question back to the top of the Active list, but caused no other issues. There is this, related Meta -  suggesting a different approach; one I'm not keen on, especially as low rep doesn't always signify new user to Stack Exchange, maybe just a stack in which a more generally experienced user has a relatively small interest.

This is sort of similar to , which was positively received, but was declined for technical reasons. I propose that users who are editing a post that was closed within the last five days be shown a notice on top of the edit form indicating that the post will be added to the reopen queue if edited, and that if one does not plan on editing the post into a state where it can be reopened, one should wait until five days after closure to make the edit. Closed questions are only added to the review queue once per closure by editing, and if a user comes by and makes a minor (yet benign) edit, the diff that reopen reviewers see is just that of the minor edit, and as such they dismiss the task as "Leave Closed", which prevents it from being added to the queue again by another edit. This deprives the post author (and others interested in seeing the question reopened) of their chance to get the post reopened by editing. While some of these edits may be performed by users using (semi-)automated tools who would thus not see or overlook the warning, this will be a big help because 99%+ of users make edits solely manually and would thus see and possibly respond to such a notice. To help make this request more technically feasible, I propose that it instead only be loaded with the edit form, and that it should only be shown to users who can make binding edits. (Suggested edits occur at the time of approval, and the request to let the reviewers know has already been declined.) Here's an example of what I'm expecting:  This question was recently [closed/marked as duplicate]. This question will be added to a queue for possible reopening if you make this edit. If you are not planning to edit this post into a state where it can be reopened, please wait until [date and time after 70 days] to make your edit. If you are only making edits to the question's tags, please ignore this notice.


The following is my IOperation interface which has two signatures :  public interface IOperations {      int Mul(int a, int b);     int Sum(int a, int b); }   In the Operation class i have implemented the aforementioned methods:  public class Operations:IOperations {   public  int Mul(int a,int b)     {           return a * b;     }    public  int Sum(int a,int b)     {           return a + b;     } }   Now in the main Program how should i meet the DI?like this?      static void Main(string[] args)     {         IOperations myOperations = new Operations();          myOperations.Mul(3, 2);       }

There have been several questions already posted with specific questions about , such as when to use it and what frameworks are there for it. However,  What is dependency injection and when/why should or shouldn't it be used?


im a 2nd year Computer Science student, and I wanted to start doing research.  Im looking for a topic to research on, or more specifically i want to know how researchers do the following:   Find a research question they can answer Manage to actually solve that question   Do they try to research in more than one area and see where they can do progress? or are they focused on some specific question? If so, then how would you know you can actually solve it?  In addition, where can I find inspiration for research topics?  And just general information on me: im an 18 years old student, and i do my CS degree through a special program. Last year, i have done a project with 4 of my friends (under supervision of the program director). In the project, me and my friends took a (20 years old) paper, and wanted to improve and implement the ideas shown in it. Honestly - It was really fun to try and think up new ways to improve it (and we did!), and since then I really have wanted to write a research paper of my own - but i have no idea how to get started

As a very new researcher who is exploring the best way to generate ideas, some guidance on this question would be very helpful. I have found that this is NOT easy. Ideas seem to pop out of my Professor every day and I wonder how he does it. This question is broad;   How do you tend to come up with initial/seed ideas? What is your search method (if you have one)? What proportion of your ideas for past papers come from; (i) colleagues, (ii) intentionally browsing the literature for ideas, (iii) on the spot inspiration, (iv) conferences, (v) other? How do you prioritize research ideas? Is there any special, generalizable method that you've discovered to sift out those ideas that are likely to be unrealistic early on in the process of idea generation?   Based on small amounts of anecdotal evidence I have reason to believe that there is vast heterogeneity among professors regarding the above questions. For example, economist Steven Levitt says he works on 22 papers at once. A professor I know will have maybe 25% of this at any one time.  Related but not duplicate:


There exist finitely generated algebras over a field that are integral but not Cohen-Macaulay (bottom of ). What is an example?

Question 1 Could you find a non Cohen-Macaulay ring $A$ without zero divisors.  I would like $A$ to be as simple as possible. For instance, I want $A$ to be finitely generated alegbra over $\mathbb{C}$.  Comment I found plenty of examples of non Cohen-Macaulay rings in wiki and from other sources. But those rings are not integral domains.  Question 2 A projective curve is called ACM if it's homogeneous coordinate ring is Cohen-Macaulay. It would be great if one give me an example of non ACM curve in $\mathbb{P}^3$.


You cannot generate attacks of opportunity with Thorn Whip. However there is a second level spell, Spike Growth, which inflicts 2d4 per 5ft of movement. So if Thorn Whip is used to pull an enemy 10ft through spike growth, would they take 1d6 (TW) + 4d4 (SG) damage?

PHB p. 195 states that involuntary movement does not provoke :     You also don't provoke an opportunity attack when you teleport or when someone or something moves you without using your movement, action, or reaction.   Is there a general rule somewhere about involuntary movement and how it interacts with other effects?  The question arose at our table about what happens if a creature is dragged via the Thorn Whip spell across an area of Spike Growth.  Does the involuntarily moving creature take the damage from the spikes as if he'd voluntarily moved through them?    Logically, yes, if you're being dragged through spikes, you take damage from them as if you'd walked through them. But logically, if I drag you past my ally, my ally would be able to make an Opportunity Attack, likely more easily than if you were moving under your own power.  Presumably that is not allowed for balance reasons rather than versimilitude reasons, so I wonder if the same should apply to other effects?


If $A+B+C=180^\circ$   and   $\tan \left[\dfrac{A+B-C} 4 \right] \tan \left[ \dfrac{-A+B+C} 4\right]  \tan\left[\dfrac{A-B+C} 4 \right] =1$  then prove that  $ 1+ \cos A + \cos B + \cos C = 0$  I tried to use the formula of $\tan(A+B+C)$, but couldn't solve it.

If $\alpha + \beta + \gamma = \pi $ and $\tan(\frac{-\alpha + \beta + \gamma}4)\tan(\frac{\alpha - \beta + \gamma}4)\tan(\frac{\alpha + \beta - \gamma}4) = 1$  Then prove that:     $1 + \cos\alpha + \cos\beta + \cos\gamma = 0$.   I have no idea how to go about this.   Please help.


I have been using the beta Stack Exchange official app for three days. The notification system is amazing. I receive a new comment and my phone vibrates instantly! Just gorgeous! Now I know whenever I'm mentioned, or if someone posted a comment to me.  But I miss a feature: Notifications for reputation changes   All know what I'm talking about: We are aaaaalways checking for reputation changes, and would be amazing if we receive phone notifications when someone upvote/downvote our questions or if someone has accepted our answers. Just like in the achievements tab recently added to the web client.  So: Are reputation notifications listed on the app roadmap, or there is a problem of implementing that?  As we commented, this feature should come with specific notifications settings, to allow us to disable/enable certain common notifications. I'm not someone who receives one upvote per minute, but there are some folks on the SE network (Yes John Skeet, I'm talking about you...) who could consider phone reputation notifications a completely mess, just a continuous vibration of their phone.

I would like to get a notification if my reputation count has changed. I think there is already some internal API for that. (I can see that changes in the menu bar in the top).  I'm sure that some people would not like that so that should be optional.


Does quantum theory and Planck's length of $1.6\times10^{-35}\ \mathrm{m}$ mean that the electromagnetic spectrum is not continuous as every photon can only carry a discrete amount of energy? If so, wouldn't that mean that a light spectrum with an upper and lower limit such as the visible light to us humans has a finite number of colors? I know that photons get their wavelengths from the particles they are emitted from, but couldn't we say for example that the spectrum of visible light between $380$ and $750\ \mathrm{nm}$ is $370\ \mathrm{nm}$ long and divide by the minimal length of causality that would be Planck's length there no more than roughly $2.3\times 10^{28}$ possible wavelengths and therefore colors in the visible spectrum?

The electromagnetic spectrum is a continuum of wavelengths of light, and we have labels for some ranges of these and numerical measurements for many.  Question: Is the EM spectrum continuous such that between two given wavelengths (e.g. 200nm and 201nm) there is an infinite number of distincts wavelengths of light?  Or is there some cut-off of precision with which light might exist (e.g. can light only have wavelengths of whole number when measured in nanometers, etc.)?


Let's say we have $x^2=25$ So we have two real roots ie $+5$ and $-5$.  But if we were to differentiate on both sides with respect to $x$ we'll have the equation $2x=0$ which gives us the only root as $x=0$.  So does differentiating on both sides of an equation alter it? If it does, then how do we conveniently do it in Integration by substitutions? If not then what exactly is going on here ?

I wonder that Is it true to differentiate an equation side by side. Under which conditions can I differentiate both sides. For example, for the simple equality $x=3$, Is ıt valid to differentiate both sides with respect to x. I know that I am missing some basic point but I cant find it. Thanks for your helps.


shows how to use \hfill in glosses within linguex. I can't seem to load "cgloss.sty" that is mentioned in the answer to Overleaf (by adding usepackage{cgloss} in the preamble -- or am I supposed to do something different?), and I suppose it's been superseded by "cgloss4e.sty" (at least  only mentions "cgloss4e"). If I use "cgloss4e.sty", then I end up with this:  instead of  (I used the example from the answer referred to above). How to make this look properly?

I'm writing a linguistics paper that uses a large amount of linguistic examples from a wide variety of languages, using the gb4e package. I want to be able to label each example with information about the language it comes from, as I've seen in some texts, sort of like this:   Language (family, citation, etc.)      (1) example text          glosses        'translation'    gb4e is great at formatting the examples themselves, but I can't seem to get the label placed where I want it, that is, placed immediately before the example and without an indent. Here's some example code:  \documentclass{article} \usepackage{gb4e} \usepackage{lipsum}  \begin{document} \lipsum[2]  Hungarian (Finn-Ugric, \emph{reference})   \begin{exe}   \ex \gll    J\'anos h\'aza\\               John house.his\\       \glt    `John's house'   \end{exe}  \lipsum[3] \end{document}   If the label text is outside the exe environment, it's treated like a regular paragraph, but if I try to put it inside, it gives me an error. How can I make it look the way I want? I've looked at other packages that do numbered examples, but they don't seem to have solutions either, and they also don't have the same functionality as gb4e that I need.  Any help would be greatly appreciated.


i have a HTML page that include in a iframe another page, like this:  <!DOCTYPE html> <html> <head>     <style>         iframe{width:100vw;height:100vh;border:0}     </style>     <script>         function reload(){setTimeout(function(){document.body.firstElementChild.src+="",reload()},300000)}reload();     </script> </head> <body> <iframe id="mappa" src="*********"></iframe> </body> </html>   Now i want to run a command into in this iframe, like this: $(".SimpleSliderDecrementButton").trigger("click");  How can i made this command running into the iframe?

Basically, I have an iframe embedded in a page and the iframe has some  routines I need to invoke from the parent page.  Now the opposite is quite simple as you only need to call parent.functionName(), but unfortunately, I need exactly the opposite of that.  Please note that my problem is not changing the source  of the iframe, but invoking a function defined in the iframe.


I have always wondered this and apologize if I'm reposting, but I don't know how to find out the answer, also Im a little new to math but always liked it, and I'm learning and am starting out with complex analysis, so here goes. I believe:  $i={\sqrt {-1}} = {\sqrt {\frac{1}{-1}}} = {{\frac{\sqrt {1}}{\sqrt {-1}}}}=\frac{1}{i}$  But that gives you $i^2=1$ and not $-1$. Where did I go wrong?

i have a pretty nasty question. i was glancing through a few olympiad papers and stumbled upon this question:  prove that  $ i = \sqrt {-1}\ $.  i tried the conventional methods namely euler's formula  but could not figure what to do next. how do you actually proceed further? i have checked a few books and a proof is not available.are there any proof available for this


I'm currently finishing up my last year of study as an undergraduate mathematics major at a top 2 public school.  I've been interested in getting a phD in mathematics for some time now, but my GPA and work in some classes in my 1st and 2nd years leaves a lot to be desired.   Let's just say I got pretty bad grades in important classes.  Since then, I've worked my but off and currently have around a 3.3 GPA.  Luckily, I was accepted into a Statistics/Computer Science related Masters program.  In this program, I will have the opportunity to take electives and plan to take some higher level math classes.    My question is, will doing very well in my masters program next year override my poor performance as an undergrad? Also, should I be really trying to get a research position this summer?

Suppose you do bad in undergraduate school in say computer science. But you do very well in a masters program in computer science. If you want to apply to a PhD program in computer science, will the masters degree grades offset the undergraduate degree grades?


I am tring to write a .bat file to delete files older then 30 days in a specific folder I have tried several diifrent format with no luck.  the closest one  i got is  del C:\temp\temp d -30   edit..... ok so i got forfilles /p c:\temp\temp /d  how can I make it use the date when its ran instead of always having to go in and change it evrytime I run it and get them to delete them now can any one help me out thanks

I am looking for a way to delete all files older than 7 days in a batch file.  I've searched around the web, and found some examples with hundreds of lines of code, and others that required installing extra command line utilities to accomplish the task.  Similar things can be  in just a couple lines of code. It seems that something at least remotely easy could be done for batch files in Windows. I'm looking for a solution that works in a standard Windows command prompt, without any extra utilities. Please no PowerShell or Cygwin either.


In my application it contains some secure information so I implemented passlock. It is opening the passlock screen and when entered credentials application starts from first activity but what I need is, from which activity I have paused I should get that activity and navigation from there. How can I do this? I tried with android:label="@string/app_name" and android:launchMode="singleTask"but its not working as desired. Please help me.  I referred with this      Thank you in advance

I've been working on the Android SDK platform, and it is a little unclear how to save an application's state. So given this minor re-tooling of the 'Hello, Android' example:  package com.android.hello;  import android.app.Activity; import android.os.Bundle; import android.widget.TextView;  public class HelloAndroid extends Activity {    private TextView mTextView = null;    /** Called when the activity is first created. */   @Override   public void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);      mTextView = new TextView(this);      if (savedInstanceState == null) {        mTextView.setText("Welcome to HelloAndroid!");     } else {        mTextView.setText("Welcome back.");     }      setContentView(mTextView);   } }   I thought it would be enough for the simplest case, but it always responds with the first message, no matter how I navigate away from the app.  I'm sure the solution is as simple as overriding onPause or something like that, but I've been poking away in the documentation for 30 minutes or so and haven't found anything obvious.


I have a SanDisk Cruser Blade USB stick that suddenly seems to be write protected. I tried running DiskPart but after I write the command "attributes disk clear readonly" it displays this:  Microsoft DiskPart version 5.1.3565  ADD         - Add a mirror to a simple volume. ACTIVE      - Marks the current basic partition as an active boot partition. ASSIGN      - Assign a drive letter or mount point to the selected volume. BREAK       - Break a mirror set. CLEAN       - Clear the configuration information, or all information, off the disk. CONVERT     - Converts between different disk formats. CREATE      - Create a volume or partition. DELETE      - Delete an object. DETAIL      - Provide details about an object. EXIT        - Exit DiskPart EXTEND      - Extend a volume. HELP        - Prints a list of commands. IMPORT      - Imports a disk group. LIST        - Prints out a list of objects. INACTIVE    - Marks the current basic partition as an inactive partition. ONLINE      - Online a disk that is currently marked as offline. REM         - Does nothing. Used to comment scripts. REMOVE      - Remove a drive letter or mount point assignment. REPAIR      - Repair a RAID-5 volume. RESCAN      - Rescan the computer looking for disks and volumes. RETAIN      - Place a retainer partition under a simple volume. SELECT      - Move the focus to an object.   It's like when you type help at the DiskPart prompt, so how do I get past this? This problem started  when I plugged the stick into a laptop which had viruses, if that's any help.

My flash disk encountered an error saying that it has been write protected, so of course I can't even copy files or even format my flash drive.   What happened to my flash drive to cause this?   And is there a way I can I fix this?


I am new in shell.  I'am writing a very basic script:  #!/bin/bash example() {      echo "Code that don't need sudo."     sudo -s      echo "Code that need sudo"  }  example   After running this script i expect :   prompt Code that don't need sudo. shell ask me password  if the password is OK prompt Code that need sudo.   But after typing the good password the prompt Code that need sudo. does not appear why and how to fix it ?

I am trying to make a script like this:  #!/bin/bash sudo -s something...   When I execute it, I get a new shell but something is executed only when I exit the shell created by sudo -s, not inside it.  Any help?


I define   typedef std::map< int, std::set<int> > SparseMap;   Then I try to insert a pair in that way:  pair<SparseMap::iterator,bool> result; result = sparseBlue.insert(SparseMap::value_type(row, set(col)) ); //errors    if(result.second)          cout << "Inserted" << endl;    row and col are integer matrix coordinates sparseBlue is declared as SparseMap sparseBlue;   Why do I get those errors at the line in which I .insert?

In templates, where and why do I have to put typename and template on dependent names? What exactly are dependent names anyway?    I have the following code:  template <typename T, typename Tail> // Tail will be a UnionNode too. struct UnionNode : public Tail {     // ...     template<typename U> struct inUnion {         // Q: where to add typename/template here?         typedef Tail::inUnion<U> dummy;      };     template< > struct inUnion<T> {     }; }; template <typename T> // For the last node Tn. struct UnionNode<T, void> {     // ...     template<typename U> struct inUnion {         char fail[ -2 + (sizeof(U)%2) ]; // Cannot be instantiated for any U     };     template< > struct inUnion<T> {     }; };   The problem I have is in the typedef Tail::inUnion<U> dummy line. I'm fairly certain that inUnion is a dependent name, and VC++ is quite right in choking on it. I also know that I should be able to add template somewhere to tell the compiler that inUnion is a template-id. But where exactly? And should it then assume that inUnion is a class template, i.e. inUnion<U> names a type and not a function?


Citizens of my country don't need a schengen zone visa to enter. however we're allowed to stay 90 days on a 180 period. i travelled for three month and didn't count properly and stayed 91 days. when I left the schengen zone i wasn't told anything. i haven't received any notice either.   how can i know if i'm facing any consequence? i'm planning on travelong again for three months, obviously respecting the three month period that i have to wait. is there any chance they won't let me in the schengen zone?

According to law, what are the consequences of a US citizen overstaying a Schengen visa?  In practice, how likely is one to be penalized for overstaying by a day, 10 days, and a month?  Are there countries that are more likely to enforce the rules on departure?


"An active device or component is something which can provide an infinite energy or non-zero power for an infinite interval"   I learned this definition for an active device in a book, which is valid for capacitor, inductor and batteries (I have evaluated). I was wondering what is a "PN junction", "junctions of a transistor", "OPAMP", "JFET", "MOSFET"? I mean what are the above mentioned devices inside the quotation marks? Are they active devices or passive? If either one then please provide explanation for my understanding.

While I (most of the time) know from experience what components are generally considered active or passive, I have yet to come across a satisfying definition.  Why do we divide electrical components into those two main categories at all?  Some examples:  From      Active: Those devices or components which produce energy in the form of Voltage or Current are called as Active Components   Passive: Those devices or components which store or maintain Energy in the form of Voltage or Current are known as Passive Components     How does a Diode "produce" energy?  From      What is the difference between active and passive components?   1. Active devices inject power to the circuit, whereas passive devices are incapable of supplying any energy   2. Active devices are capable of providing power gain, and passive devices are incapable of providing power gain.   3. Active devices can control the current (energy) flow within the circuit, whereas passive devices cannot control it.   What exactly means "can control current flow"? Isn't a (passive) capacitor able to control or at least influence current flow as well?   Some people argue, that it depends on the context in which the component is used to be able to consider it active or passive. This doesn't make things easier.  Especially for diodes there are so many conflicting/different arguments:   "In most cases (rectifier, Zener, etc.) a diode is, no doubt, a PASSIVE device. Only in some special cases like with a tunnel diode, when its negative resistance region is used, it can be considered as an ACTIVE device." "it is an active device.since its impedence is positive,or v-i chara lies in 1&2 quadrants." "Yes it is an active device since it requires an external power source, to operate it in forward or reverse bias." "Diode is an active device, since it can be used as an waveform generator (half wave rectifier, for ex)." "If the i-v characterisitics of the diode are in region I and III, then it is a passive device (always dissipating power). I think most diodes fall into this category."   I am pretty sure that there is no "one rule" and you always have to ask several questions about a component that must be satisfied to classify it. But what are those criteria exactly?


We use "is" with singular but here we use "is" with two things: "name and address". Why?

I was surfing the internet the other day when I found this phrase: Instead your precious time and attention is wasted. To my ears, it sounds wrong. But I'm not a native English speaker, so I consulted with a number of them, and some of them said that it was "is" because the adjective modifies only the noun "time" and not "attention". Others said it "is" because that's just how it is. But I still believe it should be "are". Any help is appreciated.


When I run: sudo apt-get install libpng12-0, I get this error message:  Reading package lists... Done Building dependency tree        Reading state information... Done Package libpng12-0 is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  E: Package 'libpng12-0' has no installation candidate    How to fix this? Is having libpng16-16 installed enough to do what libpng12-0 does?   I have:  Distributor ID: Ubuntu Description:    Ubuntu 17.04 Release:    17.04 Codename:   zesty

I tried to install WPS Office on my laptop (ubuntu 16.10 Gnome, 64 bit) with  Gdebi installer but it said   Dependency is not satisfiable: libpng12-0   Then I tried to open this library as follows  sudo apt-get install libpng12-0   But I encountered an error:  Reading package lists... Done Building dependency tree        Reading state information... Done Package libpng12-0 is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  E: Package 'libpng12-0' has no installation candidate   Can anyone help? Thanks a lot


Can they all be amalgamated into the main site with their own tags? The reasons I can think of that this is a good idea are:  There are a lot of questions on the child meta sites that are duplicates of questions on the main site.  The child sites do not offer any reputation points and so the questions/answers cannot be taken seriously.  The main site would gain more traffic.  A lot of the child sites for the smaller sites are never used.

How do per-site metas, such as Meta Writers Stack Exchange or Meta Stack Overflow differ from the general Meta Stack Exchange?  Where should I go to ask my question?


Since I upgraded to 18.04  (well, technically, did a clean install), Kile no longer funcitons properly. More specifically, I added kile to favourites and there is an icon for it in the launcher bar (is that the right name?). However, when I click it, it opens a window that is bound to some strange "forbidded" icon in my launcher bar (see image below, the icon under kile is where kile resides when opened).  Does anyone know how to fix this?      Update: solved, by following the solution from   Thanks to     for pointing this out

I'm using Ubuntu 17.10 with GNOME shell and Numix-Circle icon theme.   When I hover over the Numix icon for Nightly Web Browser, which is pinned to the dock I get the title "Nightly Web Browser".      But when I launch the program, another icon pops up at the bottom, with the name "Nightly".


What is the simplest way to understand three-way interactions? My interaction was negative and main effect was negative. Other interaction was negative and main effect was positive.

There is a significant 3-way interaction in a data-set I'm working with.  The interaction involves both categorical and quantitative variables.  I have been pointed towards simple slopes and this  but I find the explanations lacking. I only have a basic background in statistics, and Googling for other examples has not been very helpful.   Any insight as to how to begin to understand this interaction will be very welcome, especially using R rather than SPSS. Thank you very much in advance, from a lower-year college student who has suddenly found himself over his head!


In \URL --- \% appears as \% instead of %.  But % itself works as a comment...

I'm using the url package. Now, I have some some url with a percent sign in it and want to place it in a footnote. When I let the % where it is, I get a comment, and the whole thing fails to compile because of some unmatched brackets. When it's at the end of a line, it doesn't show up at all in the result. When I write \% instead, this gets literally into the output—but I want the url to be displayed correctly.  What could I do?


was trying out this LeetCode question   The output supposed to be [3,2,1,4,5] but I keep on getting [3,2,1,4]. I believe there's problem with my current pointer but couldn't think stop it from referring to head. I'm new to C++ by the way. Any assistance would be greatly appreciated. class Solution { public:     ListNode* reverseKGroup(ListNode* head, int k) {         // head = [1,2,3,4,5]         k = 3;         cout << "RECURSE" << endl;         ListNode* current = head;         ListNode* next = NULL;         ListNode* prev = NULL;         for(int i = 0; i < k; i++){             if(head == NULL){                 return current;             }else{                 next = head->next;                 head->next = prev;                                  prev = head;                 head = next;             }         }                  current->next = reverseKGroup(head, k);         return prev;     } };

What is the difference between    a parameter passed by reference a parameter passed by value?   Could you give me some examples, please?


I have put the following formula in a latex document but I am getting an error missing \right.  \begin{multline}     \int\;\dd^3\vec{x}\int\frac{\dd^3\vec{k^\prime}}{2E(\vec{k}^\prime)(2\pi)^3}     \left(         (2\pi)^3\dirac{3}{\vec{k}^\prime-\vec{k}}         \e{i\dots}a^\dagger(\vec{k}^\prime)\\         +(2\pi)^3\dirac{3}{\vec{k}^\prime-\vec{k}}         \e{i\dots}a(\vec{k}^\prime)     \right) \end{multline}   Note that if I remove the \\ then it works fine, ie;  \begin{multline}     \int\;\dd^3\vec{x}\int\frac{\dd^3\vec{k^\prime}}{2E(\vec{k}^\prime)(2\pi)^3}     \left(         (2\pi)^3\dirac{3}{\vec{k}^\prime-\vec{k}}         \e{i\dots}a^\dagger(\vec{k}^\prime)         +(2\pi)^3\dirac{3}{\vec{k}^\prime-\vec{k}}         \e{i\dots}a(\vec{k}^\prime)     \right) \end{multline}   That ^^ works.

I have a multi-line equation that I want to have matching sized parentheses. The advice I read online was to use \left( equation \right. \\ left. rest-of-equation \right) . However, this syntax leaves first half of the equation unaware of what is in the second half. For example, if you include a square root term after the break, the second parenthesis will be larger than the opening parenthesis. When you are using the aligned environment to split a long equation this can look somewhat offputting.    Compare the top equation to the bottom one. The parentheses match in size for the bottom equation, but the left hand parentheses for the top one is  noticeably smaller.  Top Code:   \begin{aligned}[t]   \gamma_{\text{u}} + \frac{1}{108}   \left(57\gamma_{\text{er}} \right. &+  38\gamma_{\text{se}}\\ & {}\pm  \left.\sqrt{2601 \gamma_{\text{er}}^2 + 3648  \gamma_{\text{er}}\gamma_{\text{se}} + 1444 \gamma_{\text{se}}^2}  \right)   \end{aligned}   Bottom Code:  \begin{aligned}[t] \gamma_{\text{u}} + \frac{1}{16} \left(9\gamma_{\text{er}}  +  6\gamma_{\text{se}} \pm  \sqrt{49 \gamma_{\text{er}}^2 + 76 \gamma_{\text{er}}\gamma_{\text{se}} + 36 \gamma_{\text{se}}^2} \right) \end{aligned}


When we highlight words with quotation marks, should the periods and commas be within or outside of them?  Examples:  Question 1  A) He is such a "good guy."  or  B) He is such a "good guy".  Question 2  A) This smartphone is the "smartest," you should get it.  or  B) This smartphone is the "smartest", you should get it.  If possible, kindly explain why are you picking those choices.  Thank you.

I have been/am being taught that end punctuation should always go inside quotes. For example, you are supposed to write:     Marvin thought it was "awful."   The problem is I do not see how does this make sense. Intuitively, I always wrote:     Marvin thought it was "awful".   as that makes more logical sense — you want a quote to be an exact replication of what somebody else said, so why should you add punctuation inside?  I always thought it made more sense to not touch the quote and add anything after or before if it must be added.  So, why should I put end punctuation inside quotes?


I have two features for a binary classification problem which are highly positively correlated. (0.79) But when I build a logistic regression classification then I see their weights are opposite in sign. This gives different insights on the response variable based on these features.   Why is that?   Please note there is no correlation in any other features. If I drop one of these features and keep only one of them in the model, still the sign is different for the feature kept separately.   Is this multicollinearity? I mean it is to some extent but then dropping one of the feature should then give sign of individual retained feature same right?.   How to rectify this?

I have a data set with highly positively correlated features that I'm classifying with LR. AFAIK correlated weights are not a problem in the same way they are in Naive Bayes - overcounting will not occur with LR.   The strange things that I'm seeing is that some of the highly correlated features assume opposite weights: feature A might be highly positive and feature B highly negative, though not as much. Is this a symptom of something going wrong with optimization or is this expected (a priori I expect A and B to be positive class indicators)


Assume $a_n \geq 0$ and a decreasing sequence and $\lim a_n = 0$  The examples I have in mind are $\sum \limits_{n=1}^\infty \frac{1}{n}$ and $\sum \limits_{n=1}^\infty \log \left ( 1 + \frac{1}{n} \right ) $ both diverge. But what if we extract a subsequence of even numbered indices.  What about for a general subsequence?

Let $\sum_{n=1}^{\infty}{a_n}$ be a series such that for each $n$, $a_n>0$ and $(a_n)$ is decreasing. Suppose that $\sum_{n=1}^{\infty}{a_{2n}}$ converges. Prove that $\sum_{n=1}^{\infty}{a_n}$ also converges. I try to prove by using definition but I got nowhere . Can anyone guide me ?


I used Cubic to edit an Lubuntu iso to fit my needs and so far it has worked really well. However now i need to change the default config of some packages. I know that the file that i need to replace is located in the .config directory. But i don't know where this folder is located. Since there is no user account while using cubic only the root account. Sorry for my bad English and thanks in advance.

I am looking for tools for Ubuntu that can be used to EDIT ISO Images. Including ISO images that are bootable like Ubuntu and Windows ISOs. Not only edit but save the edited ISO and can still boot when burned on an USB Drive or CD/DVD.


I have a question considering the difference between Raman Scattering and fluorescence.   I know that Raman Scataring is a non-resonant process, while fluorescence is resonant, that Raman scattering retains coherence while fluorescence doesnt and that in Raman scattering the photon is "emited" immediatelly while there is some specific time dependent decay in fluorescence. These things are clear.   What is not clear to me is why the Raman Scattering is supposed to be 2-photon process, while fluorescence is 1-photon process (I actually read this in some book that had some kind of Feynman diagrams in it - but no further information). Can someone please explain this? The more detailed explanation, the better :).   Thank you very much.  EDIT !!!  I found the book I was talking about. There is this picture. And it basically says that in case of fluorescence the system goes through a transition state (excited state) at one time - photons interact with bra and ket vector at the same time. While in Raman one photon interacts with bra vector, it is emited and only then the second photon interacts with ket vector (and is once again emited). This is their reasoning for this 1-photon/2-photon stuff.   Do I understand it correctly? And is it even explained well?

What is the difference between  and ?  Both phenomena involve the emission of photons shifted in frequency relative to the incident light, because of some energetic transition between states that the system undergoes. As far as I can tell, fluorescence is caused by ionization of the atomic electrons while Raman scatterings agitate phonon modes - but technically speaking, aren't they effectively the same?


I am trying to fetch a range of rows in Oracle, but I am only able to fetch from the first row to a row number N.   I cannot do it in case i want to fetch a range in-between the table such as row no. 2 to 5   Lets consider EMP table below that is seen in the sample user SCOTT    Case 1: Fetch a range of rows from 1 to 5, I get the following  select EMPNO, ENAME from (select EMPNO,ENAME from EMP ORDER BY EMPNO)  WHERE ROWNUM BETWEEN 1 AND 5     Case 2: Now lets try and fetch 3 rows between 2 and 5.   select EMPNO, ENAME from (select EMPNO,ENAME from EMP ORDER BY EMPNO)  WHERE ROWNUM BETWEEN 2 AND 5     This gives me an empty Resultset. Why is that? What do I need to change so that I can get a range of rows from somewhere in between the table?

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.


The question pretty much says it all, Is there a max number of answers per day. While I'm at it is there a max number of questions.    If there isn't does anyone think it should be implemented.

I noticed that I can only perform certain actions such as commenting a finite number of times in a given period of time. Obviously, rate limiting is in place to prevent accidental misuse or intentional abuse of certain features.  Where else is rate limiting applied on Stack Exchange sites, and what are the limits?


How do I copy and paste only the results of a calculation without copying the formula behind it? I'm learning to use Open Office Calc. I remember other spreadsheets that had a values function, or simply a menu choice to paste values instead of the formulas, but this idea seems to be missing from Open Office, or called by some other name. Thanks for any help.

How do I copy and paste the text (not the formulas) from one Calc sheet to another in OpenOffice?


I've implemeted jquery datepicker on a textbox and datepicker is poping up with browser's default autocomplete that's confusing for the usera. I've tried autocomplete="off" but it's not working.

How do you disable autocomplete in the major browsers for a specific input (or form field)?


How do I draw a simple point using the tikz package? I can draw a line, a square, a circle and more, but not sure how to draw a point. I tried  \draw(0,0);   expecting it to plot a point, but that didn't work.  Any help would be appreciated, thank you. :)

The below is part of my TikZ picture:  \begin{tikzpicture} \draw (0,0)--(10,0); \filldraw (0,0) circle (3pt); \end{tikzpicture}   I want to place a "square mark" to denote the point at (10,0). How can I place a square mark? Is there anything like  \filldraw (10,0) square (3pt);   In addition, how may I place a "triangle mark"?


Will the companion perks still work if they are not following me or if I'm with different companions?

Every companion provides a unique perk. I read that you gain the perk after you reach positive reputation with your follower.  Is the perk permanent after you unlock it with reputation (stays active even after you dismiss the follower)?  Do you loose the perk if reputations drops after maxing it out?


So i have just installed Ubuntu (Minumal Installation) on Virtual Box Mac. I cant install any software form apt. It gives me error saying E: Unable to locate package cmatrix  i have had this problem before and fixed it by somehow updating snapd (I deleted the vm). Now when i try to do that it gives me an error. then it goes away. But nothing channged. I have also tried sudo apt update but it fails E: some index files failed to download  Edit: i tried the  and it did nothing heres the new full error message note: i made this change before but it seemed to not have saved because it was back to nz.archive.ubuntu.com E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/focal/restricted/source/by-hash/SHA256/e4c92ef2e003ed3264e76c7df048b5b635c595c5ce10680b3f89761a01695ff1  File has unexpected size (13183 != 6472). Mirror sync in progress? [IP: 91.189.88.152 80]    Hashes of expected file:     - Filesize:6472 [weak]     - SHA256:e4c92ef2e003ed3264e76c7df048b5b635c595c5ce10680b3f89761a01695ff1     - SHA1:57fab19d8cee8a3feaf7c84420350094f9937785 [weak]     - MD5Sum:55c93c10aa16a7e26010fa7bd55c7294 [weak]    Release file created at: Thu, 23 Apr 2020 17:33:17 +0000 E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/focal/universe/binary-i386/by-hash/SHA256/a00e79d71544f34be89543e090ccafce943577e1a1b997780c07bb75766750b3   E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/focal/universe/dep11/by-hash/SHA256/7c5810c7adbacd42400848d09af06dad52ce4597b16f9e7fa36141375f40da24   E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/focal/universe/dep11/by-hash/SHA256/52805f5b7237153f9b4173b0bfe51917175eff5ca0f9feeb6d4dfcdd88918f70   E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/focal/universe/dep11/by-hash/SHA256/b8a6c70d793758b8e231f5b901156049aa562872fd9df0a807ca3c9df6556d16   E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/focal/universe/cnf/by-hash/SHA256/ba4c9cf04162b981885818b1e3b415f841680ff60c1e647adbdd545ab1e7d17b   E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/focal/restricted/binary-i386/by-hash/SHA256/cd98f05f351d05500deef4311554710cf9bc1c39a61f198bd4733cafc9a38c98   E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/focal/multiverse/binary-i386/by-hash/SHA256/b504fbe86bb3a8ade20fcffcfc9036c732ab5f198c40d5a6a5a5685d20058966   E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/focal/multiverse/binary-amd64/by-hash/SHA256/233757b7df68e16c18ccad612ff13a8bb68fc36ac6d35f13427cafd70d8b5d42   E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/focal/multiverse/i18n/by-hash/SHA256/224cafd684a26e8bce3dfca4daf33b853c9273d13e4ada6161ce9ef38f1a567c   E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/focal/multiverse/dep11/by-hash/SHA256/d3eb7ca9f47c55f0031d59664a1b53f03ce3461ad565e3e568e00ff5a41f4fc3   E: Some index files failed to download. They have been ignored, or old ones used instead.

There are now errors when updating and I cannot install most software due to a corrupted  /etc/apt/sources.list   file. Is there a copy I can download to replace it?  The file would be for Ubuntu 12.04 (Final Beta) in the United States.


I understand how to solve problems dealing with imaginary numbers, but I don't understand the reason why they exist and what they really do. Could somebody please explain to me what the point of them is? What I don't understand is that wouldn't multiplying by negative one just do the same thing?

At school, I really struggled to understand the concept of imaginary numbers.  My teacher told us that an imaginary number is a number that has something to do with the square root of $-1$.  When I tried to calculate the square root of $-1$ on my calculator, it gave me an error.  To this day I still do not understand imaginary numbers.  It makes no sense to me at all.  Is there someone here who totally gets it and can explain it?  Why is the concept even useful?


i have been looking at this for an hour without figuring out what the problem is. The else statement is not working for some reason.   #!/bin/bash if [ $#=3 ] then echo $* else echo "error" 1>&2 exit fi

I am using the below script to move two days back when script runs at starting two days of the year and also check first and second days of every month and move two days back. if [$month="01"] && [$day="01"]; then         date="$last_month/$yes_day/$last_year"         fulldate="$last_month/$yes_day/$last_year" else         if [$month="01"] && [$day="02"]; then                 date="$last_month/$yes_day/$last_year"                 fulldate="$last_month/$yes_day/$last_year"         else                 if [ $day = "01" ]; then                         date="$last_month/$yes_day/$year"                         fulldate="$year$last_month$yes_day"                 else                         if [ $day = "02" ]; then                                 date="$last_month/$yes_day/$year"                                 fulldate="$year$last_month$yes_day"                         else                                 date="$month/$yes_day/$year"                                 fulldate="$year$month$yes_day"                         fi                 fi         fi fi  But my bad am getting the below error message Etime_script.sh: line 19: [06=01]: command not found Etime_script.sh: line 24: [06=01]: command not found


Sometimes an if statement is executed even if the condition isn't met. The condition involves a double value:  if (percentage < 10.0) cout << " ";   I use this line of code in my program and running it should output something like this:  Frequency of outcomes: Outcome 1:    10.08  % Outcome 2:    10.15  % Outcome 3:     9.98  % Outcome 4:    10.00  % Outcome 5:     9.88  %  But this happens instead:  Frequency of outcomes: Outcome 1:    10.08  % Outcome 2:    10.15  % Outcome 3:     9.98  % Outcome 4:     10.00  % Outcome 5:     9.88  %  As you can see, even though 10.00 is not less than 10.00, the if statement executes anyway. Why does this happen?  This is my code:

I have this simple test: double h; ... // code that assigns h its initial value, used below ... if ((h>0) && (h<1)){  //branch 1 -some computations } else{  //branch 2- no computations }  I listed my values as I got some really strange results and for example if: h=1 then the first branch is reached and I do not understand why since if h=1 I want branch2 to be computed. Am I getting confused by something so obvious?  Edit: This is how I compute and then use h: double* QSweep::findIntersection(edge_t edge1,edge_t edge2) {   point_t p1=myPoints_[edge1[0]]; point_t p2=myPoints_[edge1[1]]; point_t p3=myPoints_[edge2[0]]; point_t p4=myPoints_[edge2[1]];  double xD1,yD1,xD2,yD2,xD3,yD3,xP,yP,h,denom; double* pt=new double[3];          // calculate differences   xD1=p2[0]-p1[0];   xD2=p4[0]-p3[0];   yD1=p2[1]-p1[1];   yD2=p4[1]-p3[1];   xD3=p1[0]-p3[0];   yD3=p1[1]-p3[1];      xP=-yD1; yP=xD1; denom=xD2*(-yD1)+yD2*xD1; if (denom==0) {     return NULL; } else{ h=(xD3*(-yD1)+yD3*xD1)/denom; } std::cout<<"h is"<<h<<endl; if (h < 1) std::cout<<"no"<<endl; else std::cout<<"yes"<<endl; if (h==1) {     return NULL; } else{ if ((h>0)&&(h<1)){     pt[0]=p3[0]+xD2*h;       pt[1]=p3[1]+yD2*h;     pt[2]=0.00; } else{     return NULL; } }   return pt;    }  Edit: Okay, so it is clear how I should reformulate the condition. From: double h; if (h==1){    //computations here }  To: double h; if (abs(h-1)<tolerance){   //computations here }  When I use double numbers. But how do I reformulate this? double h; if (h<1){    //computations here }


So I wrote up a code that will make the user enter the name "Jack" but if he enters any other name it will say "That is not your name!" but i'm having trouble to make it do that. For example when I enter that name "Jack" It will say "That is not your name!" and when I enter a name like Joey for example it will say the same thing.  import java.util.Scanner;  public class WhoAreYou {   public static void main(String[] args){      Scanner user_input = new Scanner(System.in);      String vYourName, vNotYourName;     System.out.print("Enter your name here: ");     vYourName = user_input.next();      /*     String vNotYourName;     System.out.print("Enter your name here: ");     vNotYourName = user_input.next();     */      if(vYourName == "Jack")     System.out.println("Your name is: "+vYourName);      else{       vNotYourName = " ";       System.out.println("Thats not your name!");     }   } }   Instead if using two Strings I tried to use one and that didn't work. Any ideas?

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


Why should Jess be a victim of time loop in Triangle? Who is the driver at the start of the loop and what is his significance with respect to Jess?

In , at the start when Jess arrives at the boat for the "first" time, is this the start of the continuation of the ending scene?  It's known that the cruise ship and any surroundings after leaving it is in a time loop.  Though Jess remembers the ship and tells Greg, she makes no indication that she is in the time loop. So yes, the movie was meant to confuse the user. But seeing that, according to the number of dead Sallys on board, the time loop occurs more than 20 times.  So, the first time she entered the loop, the storm sent her into an alternate reality with the never-ending time loop? Is this what the movie was showing? I noticed there is a deadly Jess that was not really in the foreground that got shot in the head, and stabs Sally and Downey in one of the rooms. I cannot really place where she falls into the picture seeing that one of the previous Jess instances killed that Jess instead of letting her jump overboard.  So is there a separate timeline/reality?


I am planning to apply for a tourist visa for myself and my family. I am doing all of the travel expenses for my family.  Do I need to submit my six months bank statement for each application of my dependants or just submit with mine?

We are sponsoring a family to visit us in UK as friends from Madagascar for two weeks. They have a 6 year old and a 16 month old.   Do the kids need their own visas, and are they the standard visitor visa or a special child visa?   Also, when I try and apply on the website I can only apply for one person so how do I apply for all the individuals in the family?   I have looked on the Immigration website and can't find the answers I need.


I installed ubuntu 14.04.1 along side windows7. i remember that i gave automatic resizing of parition while installing ubuntu. Now i am unable to boot windows 7. on the boot screen i am having the following..  *ubuntu Memtest Memtest windows 7   Can you please help me to boot windows 7.

I just installed Ubuntu alongside to Windows 7, and now Windows 7 will not boot.  When the system starts, it shows me entry for Windows 7 in the boot menu, when I click on the Windows 7 option in the boot menu, after few seconds it will show me the boot menu again and Windows will not boot. It shows me no error message. Windows 7 option is available in the boot menu but it just does not boot.  Here are my boot info results   update - 30/01/2012 I tried windows recovery - fix startup issues - that showed no problems but issues were not resolved  Then I tried the widnows recovery console and run following commands  bootrec /fixboot bootrec/ fixmbr bootrec /RebuildBCD   But that does not help, Now neither ubuntu nor windows will boot. When I boot from windows CD it shows me a valid windows installation in c:\ drive.  update After a lot of help I got from #ubuntu channel and trying out different things, ultimately I can now boot both windows and ubuntu, still, the issue is not completely resolved though.  Here's what made it work  Boot using ubuntu live CD and then run the testdisk utility as steps mentioned  Restart system and I was able to see the boot menu and boot into Ubuntu, then put the following code in boot/grub/custom.cfg. Restart and now I can see one more entry to boot win7, clicking on it boots windows.  menuentry "Windows 7 (loader) with grub ntldr workaround" --class windows --class os   {     insmod part_msdos     insmod ntfs     set root='(hd0,msdos1)'     search --no-floppy --fs-uuid --set=root FAF0F57DF0F54085     ntldr /bootmgr }   It will make windows boot probably but now windows have a dependency on Ubuntu and I can not remove Ubuntu or else windows will stop working.  Credit goes to 'Jordan_U' on #ubuntu channel.   update Here are the win7 boot details I got from EasyBCD  Windows Boot Manager -------------------- identifier              {9dea862c-5cdd-4e70-acc1-f32b344d4795} device                  partition=C: path                    \bootmgr description             Windows Boot Manager locale                  en-US default                 {04fe8f95-4b17-11e1-a45c-909d3d25f938} displayorder            {04fe8f95-4b17-11e1-a45c-909d3d25f938} timeout                 30  Windows Boot Loader ------------------- identifier              {04fe8f95-4b17-11e1-a45c-909d3d25f938} device                  partition=C: path                    \Windows\system32\winload.exe description             Windows 7 Home Premium locale                  en-US osdevice                partition=C: systemroot              \Windows resumeobject            {8d25a443-4b0a-11e1-a835-806e6f6e6963}   Note Still, I am looking for how can I have everything clean and how can I boot windows without having a dependency on Ubuntu. so that if ever I have to remove ubuntu, windows will keep booting file without ubuntu.


Let $f : \mathbb{R}^2 \to \mathbb{R}$ be a continuous map such that $f(x) = 0$ for only finitely many values of $x$. Is it necessary that either $f(x) \leq 0$ for all $x$, or, $f(x) \geq 0$ for all $x$  I don't think its necessary because if $f(x,y)=x$ then $f$ is continous and it takes both positive and negative values.

Let  $f : \mathbb{R}^2\rightarrow \mathbb{R}$ be a continuous map such that $f(x)=0$ only for finitely many values of $x$. Which of the following is true?   Either $f(x)\leq 0$ for all $x$ or $f(x)\geq 0$ for all $x$. the map $f$ is onto. the map $f$ is one one. None of the above.   What I have done so far is :   I would take polynomial in two variables.. This need not be like $f(x)\geq 0$ for all $x$ or $f(x)\geq 0$ for all $x$.So,first option is eliminated. The map is not one one assuming that $f$ has more than one zero. So, third option is wrong.   I could not think of an example in which it is not onto..  Only examples i am getting in my mind are polynomials and they are onto..  So, I am having trouble with surjectiveness of the function.  Please help me to clear this.  Thank you..


I have an issue with the do-while code that I tried to run. I want it to repeat the process of adding the sum of two numbers together produced by the user, but the code will not run for some reason. I am new to java programming and loops. I just want to figure out why the code will not run and repeat the process of entering the numbers and adding the sum. I am not looking to compare the strings, my main goal is to make the while loop repeat the process of adding the two numbers produced by the user if they respond with Y. Thank you!     import java.util.Scanner;  public class Try {  public static void main(String[] args) {     int first;     int second;     int sum;      String repeat;     Scanner kbd= new Scanner(System.in);     do {      System.out.print("Enter the first number: ");      first = kbd.nextInt();       System.out.print("Enter the second number: ");      second = kbd.nextInt();       sum = first + second;      System.out.println("The sum is:" +sum );      System.out.print("Do you want to do this again? Y or N? ");      repeat= kbd.nextLine();     } while (repeat=="y" || repeat=="Y");       }   }


I have a data set of people switching brands. Say #people switching from Brand A to Brand B, C or D.  My data looks like this Week   | Brand   | %Switchers | Price  Week 1 | Brand B | 10%        | 10  Week 1 | Brand C | 50%        | 8  Week 1 | Brand D | 40%        | 9  I have such data for 104 weeks. Note that sum of switcher to Brand B & C & D will always sum to 100. I want to model the influence of Brand & Price on switching behavior.   Since this is a proportion data, I am applying beta regression model on to it. My equation is   betareg(%Switchers ~ Brand + Price)  The model coefficients are significant & model fit is decent. However, the while I predict switching behavior across brands I am finding that sum(%Switchers) along Brand B Brand C Brand D are beyond 100% (which doesn't make logical sense).   While I can see where this is coming from (the model doesn't know that sum(%Switchers) is 100% in a given week), I am stumped as to how to interpret such scenarios? Also, is there some other model with will allow me to model proportions and limit their sum to 100% in a given week.    Edit: My problem is not that some proportions are zero or one. It is that sum of proportions in a given week are 1. Hence, IMHO, zero-one inflated beta regression doesn't particularly help.  Edit: I don't know why it is marked duplicate of another question. I am specifically mentioning that the linked questions doesn't help answers my key question viz What if switching probaility across brands come out to be greater than 100%

I am trying to produce a model for which I have a response variable which is a proportion between 0 and 1, this includes quite a few 0s and 1s but also many values in between. I am thinking about attempting a beta regression. The package I have found for R (betareg) only allows values  in between 0 and 1 but not including 0 or 1 them selves. I have read elsewhere that theoretically the beta distribution should be able to handle values of 0 or 1 but I do not know how to handle this in R.I have seen some people add 0.001 to the zeros and take 0.001 from the ones, but I am not sure this is a good idea?  Alternatively I could logit transform the response variable and use linear regression. In this case I have the same problem with the 0 and 1's which cannot be log transformed.


I am beginner in LaTeX, and I am trying to use BibTeX to create a reference, I am using  MiKTex 2.9 and TeXstudio 2.5.1 . I am trying to include references to my .tex file using BibTeX.   I created a .bib file (mybib.bib) in TeXstudio using the BibTeX format  %%%%%%%%%%%% mybib.bib %%%%%%%%%  @BOOK{AsmussenandAlbrecher2010,   author  = {Asmussen, S. and Albrecher, H.},   title   = {Ruin probabilities},   edition = {2nd ed.},   address = {Singapore},   publisher = {World Scientific},   year    = {2010} }  @ARTICLE{Botta1987,   author  = {Botta, R. F. and Harris, C. M. and Marchal, W. G.},   title   = {Characterisation of generalised hyperexponential distribution functions},   journal = {Stochastic Models},    volume  = {3},   year    = {1987},   pages   = {115-148} }  @BOOK{ChaudhryandTempleton1983,   author  = {Chaudhry, M. L. and Templeton, J. G. C.},   title   = {A First Course in Bulk Queues},   address = {New York},   publisher = {Wiley},   year    = {1983} }  I include mybib.bib in my .tex file test_els.tex  %%%%%%%%%%%%%%%%%%%%%%%%%%%%% test_els.tex %%%%%%%%%%%%%%%%%%%%%%%%%%% \documentclass[preprint,12pt]{elsarticle}  \begin{document} \section{Introduction} Several researchers studied ruin probability, but for a survey see\cite{AsmussenandAlbrecher2010}. For bulk arrival queues see \cite{ChaudhryandTempleton1983}  \bibliographystyle{model1-num-names} \nocite{*} \bibliography{mybib} \end{document}  I use PDFLATEX->BIBTEX->PDFLATEX->PDFLATEX and the output produced references cited in the text, but the title references is missing. Where is the mistake? Please help.

The word "References" does not appear before the references which I entered in my paper. The packages I am using are:  \documentclass[final,times,1p,leqno,11pt]{elsarticle} \usepackage[latin1]{inputenc} \usepackage{enumerate} \usepackage{amsfonts} \usepackage{amsmath} \usepackage{amsthm} \usepackage{amssymb} \usepackage{latexsym} \usepackage{multicol} \usepackage{verbatim} \usepackage{amscd} \usepackage{mathrsfs} \usepackage[usenames]{color} \usepackage[all]{xy}   What is the reason of this issue?


I need to allow access to my docker container with SQL from localhost, where my application is running. If I do IPtables default INPUT policy to ACCEPT, everything works. Can somebody help me with that one iptables rule? Thank you  -P INPUT DROP -P FORWARD DROP -P OUTPUT ACCEPT -N DOCKER -N DOCKER-ISOLATION-STAGE-1 -N DOCKER-USER -N DOCKER-ISOLATION-STAGE-2 -A INPUT -p tcp -m tcp --dport 80 -j ACCEPT -A INPUT -p tcp -m tcp --dport 443 -j ACCEPT -A INPUT -p tcp -m tcp --dport 10000 -j ACCEPT -A INPUT -s 109.100.000.0/32 -p tcp -m tcp --dport 2277 -j ACCEPT -A INPUT -s 127.0.0.1/32 -j ACCEPT -A INPUT -i eth0 -m state --state RELATED,ESTABLISHED -j ACCEPT -A INPUT -i lo -j ACCEPT -A INPUT -s 109.100.000.0/32 -p tcp -m tcp --dport 1433 -j ACCEPT -A FORWARD -j DOCKER-USER -A FORWARD -j DOCKER-ISOLATION-STAGE-1 -A FORWARD -o docker0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT -A FORWARD -o docker0 -j DOCKER -A FORWARD -i docker0 ! -o docker0 -j ACCEPT -A FORWARD -i docker0 -o docker0 -j ACCEPT -A OUTPUT -m state --state RELATED,ESTABLISHED -j ACCEPT -A OUTPUT -o lo -j ACCEPT -A OUTPUT -p icmp -j ACCEPT -A OUTPUT -o eth0 -p udp -m udp --dport 53 -j ACCEPT -A OUTPUT -o eth0 -p icmp -j ACCEPT -A OUTPUT -o eth0 -p udp -m udp --sport 123 --dport 123 -j ACCEPT -A OUTPUT -o eth0 -p tcp -m tcp --dport 80 -m state --state NEW -j ACCEPT -A OUTPUT -o eth0 -p tcp -m tcp --dport 443 -m state --state NEW -j ACCEPT -A DOCKER -d 172.17.0.2/32 ! -i docker0 -o docker0 -p tcp -m tcp --dport 1433 -j ACCEPT -A DOCKER-ISOLATION-STAGE-1 -i docker0 ! -o docker0 -j DOCKER-ISOLATION-STAGE-2 -A DOCKER-ISOLATION-STAGE-1 -j RETURN -A DOCKER-USER -j RETURN -A DOCKER-ISOLATION-STAGE-2 -o docker0 -j DROP -A DOCKER-ISOLATION-STAGE-2 -j RETURN

I have a debian server with docker 1.6.0 on it with a running official mysql container ().  I use a fairly basic firewall configuration in which all ports are closed except SSH, HTTP and NTP ().  When I try to connect to my mysql database:  mysql -u root -h 172.17.0.3 -p   I get the following error message:  ERROR 2003 (HY000): Can't connect to MySQL server on '172.17.0.3' (110)   Port 3306 is filtered on it :  nmap -p 3306 172.17.0.3  PORT     STATE    SERVICE 3306/tcp filtered mysql   ... and when I open port 3306 on the host i can access to the mysql server.  How to access the mysql server container without opening port 3306 of the host machine ?  Further information than can help:  The ansible task to launch the container :  - name: Mysql container   docker:     name: mysql     image: mysql:5.7     state: started     volumes:     - /var/container_data/mysql:/var/lib/mysql     ports:     - "127.0.0.1:3306:3306"     env:         MYSQL_ROOT_PASSWORD: my-root-password   docker inspect mysql -> pastebin.com/raw.php?i=uhXEhuXJ  iptables -L -> pastebin.com/raw.php?i=18fkgktF  ifconfig -> pastebin.com/raw.php?i=YJs2JnQx  If you need more information don't hesitate to ask me.  Best regards


In general, EFL students are taught the two main ways of pronouncing the determiner "either" are the British [ˈaɪðə] and the American [ˈiːðər] varieties. However, I've repeatedly heard from specific North American individuals (face-to-face and on TV) another pronunciation: [ˈaɪðər]. My specific question here is: does that phenomenon take place because of some dialectical/idiolectical/sociolectical background? Thanks!

There are two common pronunciations of "either": British /ˈaɪðər/ and American /ˈiːðər/. If Americans are more or less consistent in this regard, then the Brits seem to be freely using both. In fact, from what I can tell, "either this or that" is more often in the first form, whereas "me either" is in the second. But I may be wrong. Is there any kind of an informal rule in the modern British English with regard to this?


I replaced windows 8.1 with Ubuntu 16. My windows was in C drive but Now I cannot see my other disk partitions. I am new to Linux . what should I do ?  (I didn't dual booted, I replaced windows with Linux).

I have a Toshiba satellite A-200 laptop with a Vista OS on it with 4 NTFS partitions  (C:) Vista  (D:) Entertainment  (E:) Work  (F:) Sources   and I wanted to start using Ubuntu instead. So I tried it first from the live CD and everything was OK and all the partitions were shown and working and so I decided to install Ubuntu to replace Vista on the (C:) drive. After I did that I can no longer find my folders and files on the (D:), (E:), (F:) partitions and the only file system that is shown is one 198 GB although my HDD is 320 GB.  I can't access the lost data on the remaining 120 GB which I hope is still there and not totally lost  I am now working from the live CD but I am unable to install testdisk. Can I recover the Vista partitions by the product recovery CD to get my laptop back to the factory settings? Can I recover the NTFS partitions using a recovery program for Windows or will that make the problem worse?   I need these data badly as I don't have a backup for them.


I have looked up reflections in java, but still don't quite understand them. I need to "swap" values of two local parameters using a reflection. Here is what I have. I know it doesn't swap the values which is why I need to use the reflection. How do I do this?  public class SwapBla { static int x = 1; static int y = 2;  public static void swap2(int x, int y)  {    int temp = x;    x = y;    y = temp;  } }

I always thought Java uses pass-by-reference. However, I've seen a couple of blog posts (for example, ) that claim that it isn't (the blog post says that Java uses pass-by-value). I don't think I understand the distinction they're making. What is the explanation?


I'm new to Ubuntu (12.04.3). I'm trying to install handbrake and I've tried about 6 different ways non seem to work, so I'm now asking for help. Step 1 sudo add-apt-repository  ppa:stebbins/handbrake-releases  $ sudo add-apt-repository  ppa:stebbins/handbrake-releases Traceback (most recent call last):   File "/usr/bin/add-apt-repository", line 128, in <module>     ppa_info = get_ppa_info_from_lp(user, ppa_name)   File "/usr/lib/python2.7/dist-packages/softwareproperties/ppa.py", line 84, in get_ppa_info_from_lp     curl.perform() pycurl.error: (35, 'gnutls_handshake() failed: A TLS packet with unexpected length was received.')   I get and error what does the error mean and how do I fix it?    In file /etc/apt/sources.list I have this  ##ppa:stebbins/handbrake-releases deb http://ppa.launchpad.net/stebbins/handbrake-releases/ubuntu quantal main deb-src http://ppa.launchpad.net/stebbins/handbrake-releases/ubuntu quantal main     If I ignore the error and continue. Step 2 sudo apt-get update I get.  W: Failed to fetch http://ppa.launchpad.net/stebbins/handbrake-releases/ubuntu/dists/oneiric/Release  Unable to find expected entry 'deb-src/binary-i386/Packages' in Release file (Wrong sources.list entry or malformed file)  E: Some index files failed to download. They have been ignored, or old ones used instead.     Again if I ignore the message  and continue. Step 3 sudo apt-get install handbrake I get.  Package handbrake is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  W: Duplicate sources.list entry http://ppa.launchpad.net/stebbins/handbrake-releases/ubuntu/ oneiric/main i386 Packages (/var/lib/apt/lists/ppa.launchpad.net_stebbins_handbrake-releases_ubuntu_dists_oneiric_main_binary-i386_Packages) W: You may want to run apt-get update to correct these problems E: Package 'handbrake' has no installation candidate     If I use sudo apt-get install handbrake-gtk I get this.  Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies.  handbrake-gtk : Depends: libgstreamer-plugins-base1.0-0 (>= 1.0.0) but it is not installable                  Depends: libgstreamer1.0-0 (>= 1.0.0) but it is not installable                  Depends: gstreamer1.0-libav but it is not installable                  Depends: gstreamer1.0-plugins-base but it is not installable                  Depends: gstreamer1.0-plugins-good but it is not installable                  Depends: gstreamer1.0-plugins-bad but it is not installable                  Depends: gstreamer1.0-plugins-ugly but it is not installable                  Depends: gstreamer1.0-pulseaudio but it is not installable E: Unable to correct problems, you have held broken packages.   *Sigh nothing works :(

I have unistalled and reinstalled the Ubuntu Software Center as per info I found in a similar thread and I got the same response about line 91 or something like that.  I just tried to upload a screen shot but since I'm new it won't allow me to.  I also can not figure out how to cut and paste anything so I have to hand type what the error screen says, both when I attempt to open the software center and nothing happens, when I try to enter commands into the terminal to uninstall, reinstall, whatever I get the same following:  COULD NOT INTITIALIZE THE PACKAGE INFORMATION An unresolvable problem occured while initializing the package information Please report t:his bug against the 'update-manager' package and include the following error message: 'E: Malformed line 91 in source list/etc/apt/sources.list (dist parse)  E: The list of sources could not be read.,  E: The package list of status file could not be parsed or opened.   How do I report bugs?  What can be done about this.  I have searched and everything everyone says to do leads me back to the same line error message.  So, I don't know how to get to line 91 in the source list; to tell you what it says. Sorry, I'm really new to this. That is what I need is to find out how to get there and fix what it says. I would really like to NOT have to re partition my hard drive and start from scratch, so I'm really looking forward to getting this problem solved. I need to be able to install new software.


So there are several audio related things I do with my phone (which is not iOS) that I do while at my computer, and it'd be grand if I could play my podcasts or take my softphone calls on it. Is it possible with Bluetooth, or any other wireless method?

I don't have an AppleTV (yet), but I do have a Mac Mini hooked up to some decent speakers.  Is there something I can run on it, so that it acts like an Airplay audio receiver?  (Video support isn't important to me.)


I am taking the course titled Computer Science: Programming with a purpose. The course instructs us to use the stdlib.jar that they have provided for the same. I have followed the instructions to add the .jar file to the list of dependencies in the project structure. I am using the IntelliJ IDE.   When I use the import StdOut statement, it says Class 'StdOut' is in the default package. When I try using StdOut.printf("Hello World");, I get the error that says Cannot resolve symbol 'StdOut'.  What should I do?

I'm working now together with others in a grails project. I have to write some Java-classes. But I need access to an searchable object created with groovy. It seems, that this object has to be placed in the default-package.   My question is: Is there a way to access this object in the default-package from a Java-class in a named package?


I have a question of the appearance of an image within my paper.  What I want is the following thing:  \subsection{data} text text text, figure comes below \begin{figure} \centering \epsfig{file=data.eps, height=2.3in, width=3.5in} \caption{A sample black and white graphic (.eps format) that needs to span two columns of text.} \end{figure}  \section{next section} above is the figure visible and is positioned within the subsection.   Is that possible? Because now the image is positioned on top of the page itself and not inline with the section.

Is there any package or a method to force LaTeX to keep floating environments like table and figure closer to where they are declared?


I'd like to monitor my network traffic outside the local network on my main computer (a gentoo linux desktop workstation), which goes through a 3g wifi router (a Huawei e5220); this is a wifi only device, I have to connect to it directly through wireless connection, and I can't install any monitoring system on it.  I have a 10gb per month limit, but to check it I've to go on my mobile operator website and browse through 5 pages, and the web interface of the Huawei doesn't show reliable statistics. Since sometimes I have file transfers within the local network (a notebook, my mobile phone), the statistics shown in conky through totalup/totaldown or even the ifconfig's RX/TX output are not correct, since I'd just like to have the sum of R&T traffic outside of 192.168.xxx.xxx. I know that the statistics will not be precise (using other devices that will connect to internet through the 3g router, I'll never know the exact amount of used traffic if not by going to my operator's website), but an approximate value would be enough.  I already checked out other questions about iptraf, ifstat, wireshark and other tools (I don't want a graphic monitoring tool, I just need a simple output text I can use with python/bash scripting), but none of them seems to answer to my situation.  Thanks  EDIT: This is not a duplicate of : as explained I can't change the firmware of the router and it's a wireless only device, so I can't use another computer or wifi router to monitor the bandwidth.

For the past several years, I have been using a simple software bandwidth monitor on my computer to keep track of my monthly bandwidth usage. It has worked fine (more or less; the numbers are slightly off from my ISP’s online tracker).  This works fine for a single computer, but when my mother connects her laptop to my router or if I use  second computer, then monitor and managing bandwidth becomes much more difficult.  I considered running a bandwidth monitoring software on each system that is to connected and (somehow) transferring the logs to a central system to (again somehow) be incorporated into a central log file, but not surprisingly, this is a nightmare at best.  I also thought about a router solution (as has been mentioned, but it would need to be easy to use and customize).  Is there an easy way to monitor and log total bandwidth usage (ie from multiple systems)? It should not require all the systems to be monitored to be on at any specific time, nor having all systems connect through another one (i.e., they should be able to connect directly to the Internet connection).  Also, it should be able to differentiate between local and remote traffic so that transferring files between two local systems does not count towards Internet bandwidth usage.


Show that $X_1X_2/\sqrt{X_1^2+X_2^2}$ is normally distributed. Where $X_1\sim N(0,\sigma_1^2),X_2\sim N(0,\sigma_2^2)$. Try to use jacobian transformation$$ U=X_1X_2/\sqrt{X_1^2+X_2^2}$$ $$V=X_1$$but I failed to solve the integration.   Edit, $X_1, X_2$ are independent.   Edit2, my effort so far  I use $ U=X_1X_2/\sqrt{X_1^2+X_2^2}$, $V=X_1$ to do the transformation and I solve for $X_1=V,X_2=\frac{UV}{\sqrt{V^2-U^2}}$.   Then I compute  $J=\begin{vmatrix} \frac{\partial X_1}{\partial U}&\frac{\partial X_1}{\partial V}\\ \frac{\partial X_2}{\partial U}&\frac{\partial X_2}{\partial V} \end{vmatrix}=\begin{vmatrix}0&1\\-\frac{V^3}{(V^2-U^2)^{\frac{3}{2}}}&\frac{\partial X_2}{\partial V}\\ \end{vmatrix}=\frac{V^3}{(V^2-U^2)^{\frac{3}{2}}}$  Substituting $|J$| and $U,V$ into $f_{X_1,X_2}(x_1,x_2)=f_{X_1}*f_{X_2}$ and integrate with variable $V$  $$f_U(u)=\int_{-\infty}^{+\infty}\frac{1}{2\pi\sigma_1\sigma_2}exp\left(-\frac{v^2}{2\sigma_1^2}-\frac{u^2v^2}{2\sigma_2^2(v^2-u^2)}\right)*|J|dv=\int_{-\infty}^{+\infty}\frac{1}{2\pi\sigma_1\sigma_2}exp\left(-\frac{v^2}{2\sigma_1^2}-\frac{u^2v^2}{2\sigma_2^2(v^2-u^2)}\right)\frac{v^3}{(v^2-u^2)^{\frac{3}{2}}}dv$$  It seems that the integration will get value $0$, since it's symmetric in $v$.  And, I apologize for not showing my effort when I ask a question. I know it's basic manner to do it but I was lazy.

It is given that $X,Y \overset{\text{i.i.d.}}{\sim} N(0,1)$  Show that $\frac{XY}{\sqrt{X^2+Y^2}},\frac{X^2-Y^2}{2\sqrt{X^2+Y^2}} \overset{\text{i.i.d.}}{\sim} N(0,\frac{1}{4})$  I was thinking of making polar transformations $X=r \cos \theta, Y=r \sin \theta$  Then I am getting stuck at ranges of $\theta$


I can’t think of a word that describes what the instruments behind the lyrics are

I think there must be a good word for this, but can't think of what it might be.  Harmony and Melody are pieces of it, beat seems simplistic, Instrumentation seems too scientific and dull.  Any Ideas?


I just bought new macbook pro, and opened up my terminal . it shows: (base) Jiui-MacBookPro:~ myname$ I want to change that "Jiui" part that is located in front of -MacBookPro. How can I do that? I know how to change that "myname" part but don't know in front of that macbookpro. Please save me :(

My computer name in System Preferences > Sharing is set to "archos", but is showing as "iphone" on Terminal. It just started doing this after I loaded Xcode for doing iPhone development: Last login: Mon Nov  7 14:46:55 on ttys001 iphone:~ travis$   Any ideas what could be causing this?


Real curve noob here.  I'm building fan blades. I have an extruded cube and a BezierCircle. I just want to place copies of the object around the curve. But when I do wire up the object and curve It completely deforms the shape of the object rather than just position copies around the curve.  I end up with this:    How can I stop the curve altering the shape? Or am I just getting the entire approach wrong. Very confused.

I have a chain object. And i have a curve it follows. I got it to work for following curve, but chain object is not circles but both parts are more like stretched circles (ovals). Object i made with 2 toruses one rotated 90 degrees and then joined them together. I tried single torus too. But same issue. on a curve it just looks stretched oval. What can be the issue?   Thanks


My son's got a Kurio 7 tablet. I've installed the Amazon App Store on it and noticed not all apps are compatible. Bad Piggies for example won't install. The Amazon App Store says its not compatible with his device. Why is that? Bad Piggies is supposed to support Android 2.2 and the Kurio 7 has Android 4. Other than that it doesn't say anything about the requirements. What other things can make an Android device incompatible with some apps?

I own a Motorola Flipout, Android 2.1 stock ROM. According to the market the app "" is not compatible with my phone. The required Android version is 1.5 or above. How can I tell why the app will not work for me?    The Flipout has a comparably small screen. Is it possible that the publisher just forgot to mark my phone's display resolution as supported?  Note: Users from outside Germany see a different message. I believe, those country-restriction are unrelated.