The problem seems really confusing to me. I try to compare value at 0 index from a String list to uID.toString() and somehow it returns that these String differs from each other. I might not know how it works and actually haven't found a solution yet.   Thats my code: participateButton = findViewById(R.id.button2);     participateButton.setOnClickListener(new View.OnClickListener() {         @Override         public void onClick(View v) {             FirebaseDatabase.getInstance().getReference("Sports").child("Running").child(getIntent().getStringExtra("id")).child("teammateID").addListenerForSingleValueEvent(new ValueEventListener() {                 @Override                 public void onDataChange(@NonNull DataSnapshot snapshot) {                     ArrayList<String> list = (ArrayList<String>)snapshot.getValue();                     Log.d("TAG", list.get(0));                     Log.d("TAG", FirebaseAuth.getInstance().getUid().toString());                     Log.d("TAG", Boolean.toString(list.get(0)!=FirebaseAuth.getInstance().getUid().toString()));                     if(list.get(0) != FirebaseAuth.getInstance().getUid().toString() && list.size() < 2){                         list.add(FirebaseAuth.getInstance().getUid());                         FirebaseDatabase.getInstance().getReference("Sports").child("Running").child(getIntent().getStringExtra("id")).child("teammateID").setValue(list);                     }                     else{                         Toast.makeText(v.getContext(), "You are already signed!", Toast.LENGTH_SHORT).show();                     }                 }                  @Override                 public void onCancelled(@NonNull DatabaseError error) {                  }             });         }     });

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?


I have an app that has 23 ratings and 4,5 stars but if you search for the app they don't appear. If you tap on the app after searching for it, the stars appear but empty. You can only see the stars if you tap on Ratings. It's not a problem of time, the app was released in July 2013 there are ratings from that time too.!  I'm on the Spanish App Store, and looking through the categories and there are many apps that have this same problem, only few apps have the 5 star rating under their name.  So what are we doing wrong? I would assume the ratings would appear automatically.

I have an app that's been out for a couple of weeks. Its not exactly selling like hot cakes yet, but I'm pretty sure I've gotten a rating or a review by now. But nothing shows when viewing either in iTunes or directly on the AppStore on the iPhone.  Is there a standard delay as to when ratings/reviews show up, that Apple imposes, especially for new apps? Or do you think there is some problem with Apple's system?


In ArcGIS, is there a way to quickly reflect changes made to XY coordinate values in my table?  In edit mode I can change the values in my X and Y columns but I'm not able to refresh the map. Currently I export the table, make changes in an editor (e.g. Excel) and re-"create a feature class from XY table" using my new source file.

Using ArcMap 10.1, I edited the coordinates within a shapefile.   They are long/lat but the point will not move to that new coordinate on the map.   I've tried clicking on the Longitude column in the attribute table and 'calculating geometry' but still nothing occurs.


I'm not even able to select it, also don't think its an object. Please help.

In the 3d viewport I am using a border region to only render things inside the selected region. I did this with CtrlB. I cannot get rid of the region. How can I make the border disappear?


Question is that :  let $N\unlhd G$ such that every subgroup of $N$ is Normal in $G$ and  $C_G(N)\subset N$.   Prove that $G/N$ is abelian.  what could be the possible first thought (though for me it took some time :)) is to use that $C_G(N)$ is Normal subgroup (As in general centralizer is a subgroup). one reason to see this is that $C_G(N)$ is not Normal in General and $C_G(N)$ is not subset of $N$ in general.  As $C_G(N)\subset N$, we have $G/N\leq G/C_G(N)$   I some how want to say that $G/C_G(N)$ is abelian and by that conclude that $G/N$ is abelian.  I would like someone to see If my way of approach is correct/simple??   I have not yet proved that $G/C_G(N)$ is abelian. I would be thankful if someone can give an idea.  Thank You.

I'm stuck on the following practice problem.   Any hints would be appreciated.  Suppose $N$ is a normal subgroup of  $G$ such that every subgroup of $N$ is normal in $G$ and $C_{G}(N) \subset N$. Prove that $G/N$ is abelian.  I'm not sure how to use the fact that $C_{G}(N) \subset N$.  Thanks


On the , no matter which one of the subtabs (user, hot, new or synonyms) is selected, the list of related tags contains a tag itself:        To see this, click "top users" in the tag hover infobox or "more »" in the tag info page under Top Answerers. All subtabs are affected.

Only seems to be for the "Top Users" page of a tag.  Confirmed for multiple sites and tags.


Premise  Casting  on a creature with :     A monster with blindsight can perceive its surroundings without relying on sight, within a specific radius.   :     Attack rolls against the creature have advantage, and the creature's attack rolls have disadvantage.   Question  Do attack rolls have advantage against a creature with blindsight that has been blinded?

Not every creature with Blindsight is immune to the Blinded condition (like bats). However, blindsight seems to work for those that can't see, and Blinded is about not being able to See.   RAW seems to point that if someone casts Blindness on a bat, they should suffer the Blinded condition even though they have Blindsight because Bats are not immune to that condition.   Is this correct?


I'd like to use a the session id to update a specific entry in my database (as foreign key).  Session id:  $_SESSION['id'] = '1';   PDO  $sql = "UPDATE table_user set f_name = :f_name, l_name = :l_name where id = :id and fk_user = {$_SESSION['id']}";   Is this method safe for manipulation? It seems a little bit weak to me but I never worked with session ids as foreign key. Any suggestions are are very welcome. I'm sorry if this question is bad.

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


The necessary condition for $\int\limits_{-\infty}^{+\infty}|\psi(x)|^2dx$ to be integrable is that $\psi(x)\rightarrow 0$ as $x\rightarrow\pm\infty$. But this is not the sufficient condition. For example, $\delta(x)$ vanishes as $x\rightarrow \pm \infty$, but it is not square-integrable. What is the sufficient criterion for $\int\limits_{-\infty}^{+\infty}|\psi(x)|^2dx$ to converge? In the previous question $\psi(x)$ was an arbitrary function. If now $\psi(x,t)$ be an arbitrary solution (not necessarily a stationary state) of the time-dependent Schrodinger equation what is the sufficiency condition for $\int\limits_{-\infty}^{+\infty}|\psi(x,t)|^2dx$ to be finite? Does this conditions remain valid in three-dimensions?   EDIT: Can we have a continuous function $\psi(x)$ which does not go to zero as $x\rightarrow \pm\infty$ and yet the integral $\int\limits_{-\infty}^{+\infty}|\psi(x)|^2dx$ converges?

I'm studying Quantum Mechanics and I came across this which I don't quite understand: For a vector space of functions $f(x)$ to be square integrable (i.e $\int{|f(x)|^2dx < \infty)}$, the necessary condition is $\lim_{|x| \to \infty}f(x) \to 0$. Can someone help me understand why that must be the case? I sort of understand that it must not blow up at the infinities but can a (continuous or piece-wise continuous) function have a non-zero finite value at the infinities and still be square integrable?


I'll bring you to your mother's      I'll take you to your mother's   I am a bit confuse of these.  Should it bring or take?

My husband continuously uses bring versus take incorrectly. For example:     I will bring him to church on Sunday.     The correct form is to say:     I will take him to church on Sunday.     I cannot find this grammar rule in Strunk and White.  Could someone please state the rule?


I remember reading a short story a few years ago about a starship crew from Earth(?), in either their first (or a new model) FTL ship. The story opened with them in a new star system, which they had surveyed and were now preparing to leave. They duly fired up their engines and departed in FTL mode.  Later they scanned the system they'd left, only to find that its star had gone nova/supernova. After checking timings, they realised that the star had exploded at exactly the same time as they'd turned on their FTL drive. After that, it began to dawn on them they'd not looked back at Earth after leaving it using their FTL mode... Oops. The story ended with them waiting for the light from Earth's sun to reach them.  I've bought quite a few older collections, and even more anthologies (as far back as Grof Conklin in the 1940s), so would hesitate to guess even a particular decade, but have the feeling it was written by someone like Arthur Clarke, Isaac Asimov, Harry Harrison etc.

In my memory this story has a golden age feel but might be more recent.  The crew of an experimental ship reaches the destination system only to find it is going nova, discover an unknown effect of their new drive has triggered the nova, and realize at the end that they have already destroyed earth.


I'm on Ubuntu 14.04.3 LTS. I set a wget download running overnight and I wake up to the download complete but a frozen Unity interface. I changed to another tty and, with top, saw that the process ibus-daemon was using ~130% CPU. I killed it and the interface became unfrozen. I restarted the computer. Now, when I log in to Unity at the greeter, I am presented with the wallpaper and nothing else. What can I try to get Unity working?

When I login, nothing happens.   I am presented with my desktop wallpaper.    No Dash, no Launcher, nothing.


I'm curious of the C# spec says anything about the order of initializing static field's in C# 5 (.net4).  For instance:  public class Test {    public static readonly string A = "hi";    public static readonly string B = "bye";    public static readonly string DEFAULT = A; }   In testing (Mono 2.x) they seem to be initialized in the order they appear in code.  eg. As is, DEFAULT will have the value "hi", but if I move the definition for DEFAULT above A and B, it will be assigned NULL because A hasn't been assigned yet.  Is there a guarantee that the variables are initialized in order? Or is it up to the compiler?  Thanks.

While working on a C# app I just noticed that in several places static initializers have dependencies on each other like this:  static private List<int> a = new List<int>() { 0 }; static private List<int> b = new List<int>() { a[0] };   Without doing anything special that worked. Is that just luck? Does C# have rules to resolve this?  Edit: (re: Panos) In a file lexical order seems to be king? what about across files?  In looking I tried a cyclical dependency like this:  static private List<int> a = new List<int>() { b[0] }; static private List<int> b = new List<int>() { a[0] };   and the program didn't run the same (the test suit failed across the board and I didn't look further).


If I have a complex number of the form $z = a+bi$, how would I find the complex roots? I know that each root will be equidistant from each other and will form a circle, but I'm not sure how to solve for the complex roots. I also know that for a complex number with $n$ roots, each root will be rotated $2\pi/n$ radians. It's not an issue of graphing the complex roots, but it is for solving for them.

Suppose $z$ is a nonzero complex number, so $z=re^{i\theta}$. Show that there are only $n$ distinct complex $n$-th roots, given by $r^{1/n}e^{i(2\pi k+\theta)/n}$ for $0\leq k\leq n-1$.   My proof: Let $z=re^{i\theta}\in\mathbb{C}$ and $a\in\mathbb{C}$ s.t. $a^{n}=z$. Let $a=\rho e^{i\varphi}$. Then, $a^{n}=(\rho e^{i\varphi})^{n}$. Setting $\rho^{n}e^{i\varphi n}=re^{i\theta}$ and rewriting in polar form, we get $$\rho^{n}(\cos(n\varphi)+i\sin(n\varphi))=r(\cos(θ)+i\sin(\theta)).$$ Thus $\rho^{n}=r$ $\rightarrow$ $\rho=r^{1/n}$ and $n\varphi=\theta\rightarrow\varphi=\theta/n$. Thus the roots of $a\in\mathbb{C}$ have the form $$r^{1/n}(\cos(\tfrac{\theta}{n})+i\sin(\tfrac{\theta}{n}))=r^{1/n}(\cos(\tfrac{\theta}{n}+2\pi j)+i\sin(\tfrac{\theta}{n}+2\pi j))$$ for some $j\in\mathbb{Z}$ due to the periodicity of trig functions. Then, $$r^{1/n}(\cos(\tfrac{\theta}{n}+2\pi j)+i\sin(\tfrac{\theta}{n}+2\pi j))=r^{1/n}e^{i\left(2\pi j+\tfrac{\theta}{n}\right)}=r^{1/n}e^{i(\theta+2\pi k)/n}$$ for $0\leq k\leq n-1 ,j=nk\in\mathbb{Z} $.  I feel like there could be a more concise way to put this.


How can I find the XY coordinates of an HTML element (DIV) from JavaScript if they were not explicitly set?

I want to know how to get the X and Y position of HTML elements such as img and div in JavaScript relative to the browser window.


I'm trying to find an appropriate  to power my Beaglebone Green Wireless (BBGW) through Micro-USB port. Wall is 220v 50Hz.  reveals a C Power Management IC (PMIC).   Iout (Max) (A) 1.2    2-A Output Current on Power Path Linear Charger; 700-mA Maximum Charge Current  Confused. How many Amps are enough? (α) 5V, at least 1.2A (β)  5V, at least 2A (γ) 5V, at least 700mA   on Seeed Wiki  on beagleboard.org

Power supplies are available in a wide range of voltage and current ratings.  If I have a device that has specific voltage and current ratings, how do those relate to the power ratings I need to specify?  What if I don't know the device's specs, but am replacing a previous power supply with particular ratings?  Is it OK to go lower voltage, or should it always be higher?  What about current?  I don't want a 10 A supply to damage my 1 A device.


I have recently bought a MTB and it came with 27.5 x 2.1 wheels. The first thing I wanted to upgrade was to go tubeless but can’t find any tubeless tires for 2.1 tires. I wanted to know if it is possible to use a different size tubeless tire and does every rim have a designated wheel size or is it interchangeable.

We often get questions on bicycles.stackexchange about fitting wider or narrower tires to bicycles. We have a large number of these with answers suiting the specific bike or style of bicycle in question, but I have been unable to find one that provides a generic answer covering off all things that need to be considered. For most bicycles, the answer is the same regardless of the specific style and sizes of tires in question.   This is intended as a canonical question that we can point closed questions to.


How do I fix this error Exception in thread "main" java.lang.NullPointerException     at newproject.PG1.main(PG1.java:30), I believe it is about the the getTitle method, but I don't know how to correct it.  My code is below  package newproject; import org.openqa.selenium.firefox.FirefoxDriver; //comment the above line and uncomment below line to use Chrome //import org.openqa.selenium.chrome.ChromeDriver; public class PG1 {       public static void main(String[] args) {         // declaration and instantiation of objects/variables         System.setProperty("webdriver.firefox.marionette","C:\\geckodriver.exe");         FirefoxDriver driver = new FirefoxDriver();         //comment the above 2 lines and uncomment below 2 lines to use Chrome         //System.setProperty("webdriver.chrome.driver","G:\\chromedriver.exe");         //WebDriver driver = new ChromeDriver();          String baseUrl = "http://demo.guru99.com/selenium/newtours/";         String expectedTitle = "Welcome: Mercury Tours";         String actualTitle = "";          // launch Fire fox and direct it to the Base URL         driver.get(baseUrl);          // get the actual value of the title         actualTitle = driver.getTitle();          /*          * compare the actual title of the page with the expected one and print          * the result as "Passed" or "Failed"          */         if (actualTitle.contentEquals(expectedTitle)){             System.out.println("Test Passed!");         } else {             System.out.println("Test Failed");         }          //close Fire fox         driver.close();      }  }

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


Whenever I play any champion in LoL I know that I have to level up my "R" as soon as I can, because in general it's the most important skill etc.  What I was wondering is, are there any champions who do not gain much from reducing the cooldown (for those which have an utility as R, for example) and should rather use the point for something else?  I thought that for Rek'Sai this could be true, but I can't think of any other champion (besides Karma whose ultimate does not level up at all) who should even think of doing the same.

Except Udyr, are there champions whose R isn't a priority to be acquired at level 6 or level up at 11?


In my C-shell script (tcsh specifically) I have been trying to declare an array with six values: x, nx, y, ny, z, nz. After some trial and error I discovered three different ways of declaring the array I want:  set arrname = ("x" "nx" "y" "ny" "z" "nz") set arrname = (x,nx,y,ny,z,nz) set arrname = {x,nx,y,ny,z,nz}   but the following line doesn't work:  set arrname = {"x" "nx" "y" "ny" "z" "nz"}   The above line produces the following error:  Missing }.   My question is what is different between () and {} that makes the fourth declaration I've listed not work?


I'm making a lightsaber in Cycles Render. I'm pretty new to blender and only started yesterday. I've been watching YouTube Videos but usually I can't access something they have and usually messes it up. I'm fine doing compositing and Nodes I just need to know how to make this glow, Current (v)  Nodes  Current Compositing Nodes   Again I just need this to glow but i keep on messing up! Please help, thank you

I've been studying  lightsabers for a while now, and have tried to recreate the effects in Blender.  The trouble I'm having is with the blade in the compositor.  Keep in mind that I'm also trying to animate it.   First off, this is the lightsaber I've created with help from .  Obviously the color of the glow needs a little more work to be accurate, but that's not what I'm worrying about at the moment.  This is also rendered in Blender Internal, but I'm going to switch to Cycles when I got everything prepared.  The blade model is totally transparent, but its index is fed into the ID mask node.  I'm using two versions of Blender's Gaussian glow.  The glow it creates is, unfortunately, omnidirectional.  This is different than the glows Villanueva puts on his, where the white core continues into the saber emitter.  Also, unlike his, my glow flows over and obscures part of the emitter.  This also means that if prongs were placed on the emitter and closer to the camera than the blade, the glow would engulf them.  What I'm looking for is something like this:   (source: )    Where the parts of the model that are closer aren't affected by the glow, while those that are farther are.  Second, I'm trying to improve on Villanueva's method by having the glow applied to the reflection as well.  A method to have the glow applied to the blade if it's covered partly by glass would be nice, too.  Anyway, help is appreciated for any of these questions.  If there is a different way of going about this and getting the glow, like with Cycles materials, I'd be happy to know.


I'm a bit confused with matrix calculus.  Given is $$f(x) = \frac{1}{2}||Ax-b||^2_2$$ and the derivate of it is in my book $$\nabla_xf(x) = A^T(Ax-b). $$  I don't see how this works. My plan was to substitute the $L_2$ norm and derivate that. Witch give just the substitute (thing in brackets) time it's inner derivative. No clue why the inner derivative would be $A^T$.

In Andrew Ng's lectures on machine learning, on page 4 of his , he presents the cost function for the ordinary least squares regression model as:  $$ \begin{align} J(\theta) = \frac{1}{2} \sum_{i=1}^{m} (\theta^T x^{(i)} - y^{i}))^2 \end{align} $$  He then shows that the partial derivative can be shown as:  $$ \begin{align} \frac{\partial}{\partial \theta_j} J(\theta) = \sum_{i=1}^{m} (\theta^T x^{(i)} - y^{(i)}) x_j^{(i)} \end{align} $$  However in the solution set he gives the gradient of $J(\theta)$ as:  $$ \begin{align} \nabla_\theta J(\theta) = X^TX\theta - X^Ty \end{align} $$  My question is, how do I systematically go from the index form to the matrix form? As of right now, all I am doing is checking the dimensions of the matrices and making sure that they all come out correctly, but this seems to be inadequate. Yet I haven't found a good explanation as to how to convert from one form to the other. Help with this would be greatly appreciated.


In the moderator timeline for a post, flags are indicated on comments (a number, with drill-down to see the specific types).  This is helpful for figuring out what happened on a post.  I'd like to see something similar for the deleted-comments view for a user.  We can easily see all of a user's comments (deleted and not) already; I'm asking for this one additional bit of signal to be added to that view, to make it easier for mods investigating complaints about patterns of inappropriate comments.  This request is a subset of , where I asked for aggregate information and filters.  I understand that that might be hard; even having this subset, which the timeline already supports (so I hope it's not too hard), would be very helpful.  Something like this:

Moderators have easy access to all posts from a user that have been flagged (and how those flags were resolved), and we can see all comments from a user (including deleted ones).  This feature request is to give us some insight into (helpful) flags against a user's comments.  If a user has a pattern of problematic posts we'll see that, but I've seen users who leave many rude or non-constructive comments.  These get flagged, the moderator who sees the flag cleans them up, and life goes on.  It can take a while for the pattern to emerge because each moderator sees only part of the problem -- and has to rely on his memory.  Meanwhile, the user continues the activity and it can become more entrenched.  It would be better to be able to spot that early so we can talk with the user about it -- a stitch in time and all that.  I would like be able to see that a user's comments had N offensive flags, M not-constructive flags, and so on for the other flag reasons.  I can think of two places where this could be put in the interface:   On the flags page, add a summary with the counts by flag type.  Again, we only care about flags that were marked helpful.  If a user also receives spurious flags, well that's not his fault so shrug.  (As pointed out in a comment, we'd also need some indication of timing -- are these recent flags or old?) On the "all comments" page, add information about flags to each comment.  This should be on the page itself, not behind "expander" widgets, so we can search the page easily.  Even better, just as we can filter for deleted and undeleted, add filters for flag types.   Option 1 gives us summary information only.  Option 2 gives us the details of which comments they were.  I don't know which would be easier to implement.  Either's fine with me.  We know that the information about the flag exists in the system, because (a) it shows up on the flagging user's "helpful flags" page and (b) it's in the timeline.  This is a request to expose that information in a way that allows moderators to more-easily notice users with a pattern of problematic comments.  Just giving us a total number of flagged comments doesn't address the need, because obsolete flags are usually not a sign of trouble.  Often, in fact, they're the sign of a helpful user -- the user commented with a question or suggestion, the post actually got fixed, and now the comment no longer applies.  .


Just installed WinEdt cannot SAVE Russian characters. It warns: ``Some characters were lost while converting from UNICODE to CP 0. Save anyway?'' Probably, TeX converts all files to Unicode, but my old files are in 1251, and it cannot work with them. How to change the default coding to 1251?

I am using WinEdt to write my thesis and I used   \usepackage[latin1]{inputenc}   to get the French accents to be understood automatically.  It works fine for the first 2 chapters, but for some reason, when I add more chapters, it  gives me this weird symbol whenever I use accents.  This doesn't really make sense as the chapters are all joined to the document the same way!  I really can't see what's wrong.  Any idea?  So here's what it looks like:  \documentclass[msc, index, hyperref, prelimtm]{theseUL1_2}  \usepackage[latin1]{inputenc} \usepackage[T1]{fontenc}  \usepackage{lmodern}     \usepackage[francais]{babel} ... \begin{document} ...  \include{chap1/chap1} \include{chap2/chap2} \include{chap3/chap3}  \end{document}   The chapters are in different files all starting with  \chapter{name} ...


To add a bank account to Venmo, the user provides bank account number and Venmo makes two small deposits into the account.  The user must verify that they have access to the account by indicating the amounts to Venmo.  Venmo indicated they had made two small deposits into my account and indicated these amounts will manifest themselves tomorrow:    Is there any technical, regulation, or security reasons why the Venmo test transaction can not be completed within seconds?   The context is for American banks.

Based on , I figured that there might be multiple questions for distinct locales. Why do the most common transactions to or from bank accounts in the US require waiting one or more days before they are completed? In the information age, it seems like we should be able to transfer money instantly (or nearly so).


I have Ubuntu 11.04 installed in VirtualBox 4.0.10 on a Windows Vista Home Premium  32-bit host. I have a hard disk that I have added to the SATA Controller on the VirtualBox (a .VDI image). My question is, how can I access the files within that hard disk?   Thank you.

Is it possible to mount a VirtualBox drive image (.vdi) so the contents can be viewed in Nautilus etc.?  I have a windows 2000 .vdi which won't boot ("inaccessible boot device") after upgrading from VirtualBox 2.x to 3.1.6. I believe the IDE drive details have changed and that all I need to do is access the internal drive image and edit the Windows boot.ini to point to the new location.


I am using Red Hat SunOS. The software I would like to execute is sqlplus  I have two scripts:   script A: contains export PATH=/opt/oracle/product/9.2.0/bin/sqlplus where sqlplus is installed. This script calls the script B script B: contains echo $PATH and right after which sqlplus.  The fist command print the content of PATH which contains       /opt/oracle/product/9.2.0/bin/sqlplus    The latter command does NOT found in which path sqlplus is installed.  I tried executing the commands directly in the bash shell: export PATH=/opt/oracle/product/9.2.0/bin/sqlplus  which sqlplus     /opt/oracle/product/9.2.0/bin/sqlplus   My question is:   Why the script B cannot found where sqlplus is installed?

I am having a CentOS remote machine where I have hg installed. It was working fine for long time and today when I am trying to use hg  commands, I got the following errors,  [dinesh@lab test]$ hg st -bash: hg: command not found [dinesh@lab test]$   Then I realized that it might be missed from PATH. (But, how?, not sure.). I checked the which hg command and it failed to give me the path.  hg is located at /usr/local/bin/hg and using the whole path for hg, made it work. I tried adding the hg path to PATH variable like,   PATH=$PATH:/usr/local/bin/hg   which also didn't work. Then I have created an alias for hg command as,  alias hg="/usr/local/bin/hg"   which at least made it work.   But, eventually, I end up with the same issue for kdiff3 (which is also working fine till yesterday). Tried the above and only alias made it work. (again)  Now, I am in need of using hg kdiff3 command and for which I am keep on getting   /bin/sh: kdiff3: command not found   But, I have the kdiff3 extension enabled in the hgrc file for the repository. (which is again working till yesterday)  :(  [dinesh@lab test]$ cat .hg/hgrc [paths] default = ssh://remoteuser@xxx.xx.xx.xxx//repo/code  [ui] username= dinesh <dinesh.sivaji@domain.com>  [extensions] mq = fetch = purge = hgext.extdiff = hgext.acl =  [extdiff] cmd.kdiff3 =  [dinesh@lab test]$      Note : After making changes in the .profile file for PATH or alias, I am sourcing them each time, for changes to take effect.   Can anyone suggest what can I do to overcome this issue ?


Please help with below requirement.  attached 2 image, one is Data and another one is requirement.  Data= we are getting data in this format Requirement= i have to convert date in this format.  Please help with VA on priority.

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


Help me to integrate this, please. I tried to do this one for three days, but I have no idea.  $$ \int_0^{\pi/4} (\ln\sin x)^2\, dx $$

A few days ago, I posted   Prove that \begin{equation} \int_0^{\pi/2}\ln^2(\cos x)\,dx=\frac{\pi}{2}\ln^2 2+\frac{\pi^3}{24}\\[20pt] -\int_0^{\pi/2}\ln^3(\cos x)\,dx=\frac{\pi}{2}\ln^3 2+\frac{\pi^3}{8}\ln 2 +\frac{3\pi}{4}\zeta(3) \end{equation}  and the OP receives some good answers even I then could answer it.    My next question is finding the closed-forms for     \begin{align} \int_0^{\pi/4}\ln^2(\sin x)\,dx\tag1\\[20pt] \int_0^{\pi/4}\ln^2(\cos x)\,dx\tag2\\[20pt] \int_0^1\frac{\ln t~\ln\big(1+t^2\big)}{1+t^2}dt\tag3 \end{align}   I have a strong feeling that the closed-forms exist because we have nice closed-forms for \begin{equation} \int_0^{\pi/4}\ln(\sin x)\ dx=-\frac12\left(C+\frac\pi2\ln2\right)\\ \text{and}\\ \int_0^{\pi/4}\ln(\cos x)\ dx=\frac12\left(C-\frac\pi2\ln2\right). \end{equation} The complete proofs can be found .  As shown by Mr. Lucian in his answer below, the three integrals are closely related, so finding the closed-form one of them will also find the other closed-forms. How to find the closed-forms of the integrals? Could anyone here please help me to find the closed-form, only one of them, preferably with elementary ways (high school methods)? If possible, please avoiding contour integration and double summation. Any help would be greatly appreciated. Thank you.


I have a TP-Link MR3220 3G router. I'm using this router with a 3G USB modem to connect to the Internet.  Unfortunately I cannot ping the modem from outside to its DDNS address, even after disabling all security features like SPF filter etc. Since I cannot access this modem from outside through its DDNS address, I'm not able to use its port forwarding feature for my mail server.   I also noticed that its remote management feature through Web Console wasn't working properly either.  How can I fix this?

I noticed my TP-Link MR3220 3G/WiFi Router port forwarding will only work when I use the WAN port and not the 3G connection (modem).  Technically the router offers an option to use the Internet from 3G, WAN or both (given a priority). In my case I am only using 3G and apparently, the router features such as remote management and port forwarding don't work on this interface.  Can anyone confirm this? If so, is there any workaround (static routing or something)?


I would like to know how to malloc (and hen realloc) an array of a structure.  Here is my structure :   typedef struct tag {     char *key;     char *val; } tag;   I use this structure in another structure :   typedef struct node {     int id;     double lat;     double lon;     int visible;      tag *tab; } node;   I define a node *n, then:  n->tab = (tag*)malloc(sizeof(tag) * 5);   but I have an error of malloc corruption.  void remplisTag(xmlNodePtr cur, node *n) {     xmlNodePtr fils;     n->tab = malloc(sizeof(*n->tab) * 5);     if (n->tab == NULL) {         error(E_ERROR_MALLOC);     }     printf("apres malloc\n");     int taille = 5;     int ind = 0;     xmlAttrPtr attr1, attr2;     xmlChar *key;     xmlChar *value;     fils = cur->xmlChildrenNode;     fils = fils->next;     while (xmlStrcmp(fils->name, (const xmlChar*)"text") != 0) {         if (xmlStrcmp(fils->name, (const xmlChar*)"tag") == 0) {             if (ind == taille - 1) {                 n->tab = realloc(n->tab, sizeof(tag) * (taille + 5));                 taille = taille + 5;             } else {                 taille = taille;             }             /* searching for key */             attr1 = xmlHasProp(fils, (const xmlChar*)"k");             if (attr1 == NULL) {                 error(E_KEY);             } else {                 key = xmlGetProp(fils, (const xmlChar*)"k");                 if (key == NULL) {                     error(E_KEY_V);                 }                 /* searching for value */                 attr2 = xmlHasProp(fils, (const xmlChar*)"v");                 if (attr2 == NULL) {                     error(E_VALUE);                  }                 value = xmlGetProp(fils, (const xmlChar*)"v");                 if (value == NULL) {                     error(E_VALUE_V);                 }                 tag t;                 t.key = malloc(sizeof((char*)key));                 strcpy(t.key, (char*)key);                 strcpy(t.val, (char*)value);                 t.val = malloc(sizeof((char*)value));                 n->tab[ind++] = t;             }         }         fils = fils->next;     }     free(n->tab); }   In main:   node *n = malloc(sizeof(node)); xmlNodePtr cur;   in a while loop:  remplisTag(cur, n);

First off, here is some code:  int main()  {     int days[] = {1,2,3,4,5};     int *ptr = days;     printf("%u\n", sizeof(days));     printf("%u\n", sizeof(ptr));      return 0; }   Is there a way to find out the size of the array that ptr is pointing to (instead of just giving its size, which is four bytes on a 32-bit system)?


What are : at the beginning of lines used for in a Bash script? I have seen some usage of : at the beginning of lines, like in the following snippet of code: cgcreate -g "$cgroups:/$uuid" : "${BOCKER_CPU_SHARE:=512}" && cgset -r cpu.shares="$BOCKER_CPU_SHARE" "$uuid" : "${BOCKER_MEM_LIMIT:=512}" && cgset -r memory.limit_in_bytes="$((BOCKER_MEM_LIMIT * 1000000))" "$uuid"  Experiments show that : functions much like a comment (#), since nothing is printed to stdout; however, : $(echo foo > bar) creates a new file bar, so code execution does happen.

I've hacked on a lot of shell scripts, and sometimes the simplest things baffle me. Today I ran across a script that made extensive use of the : (colon) bash builtin.  The  seems simple enough:   : (a colon)        : [arguments]         Do nothing beyond expanding arguments and performing redirections. The return status is zero.    However I have previously only seen this used in demonstrations of shell expansion. The use case in the script I ran across made extensive use of this structure:  if [ -f ${file} ]; then     grep some_string ${file} >> otherfile || :     grep other_string ${file} >> otherfile || : fi   There were actually hundreds of greps, but they are just more of the same. No input/output redirects are present other than  the simple structure above. No return values are checked later in the script.  I am reading this as a useless construct that says "or do nothing". What purpose could ending these greps with "or do nothing" serve? In what case would this construct cause a different outcome than simply leaving off the || : from all instances?


When I update my system, I get the following errors:     Fetched 316 B in 22s (14 B/s)   Reading package lists... Done      W: GPG error:  trusty Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 6AF0E1940624A220   Please someone suggest me a solution to this.

I frequently cross this issue, and always have to google for an answer. Does anyone have a permanent fix for BADSIG errors from apt-get?     W: GPG error:    lucid   Release: The following signatures were   invalid: BADSIG 54422A4B98AB5139   Oracle Corporation (VirtualBox archive   signing key)


I'm interested with this table of contents  In this question there is the answer but as i'm not good in latex i don't know how to make a tex files wich works     please help me   Thank you

As you can see from the image below, I have an issue with the text alignment of extra long chapter names. How can I fix it so that the text will not go further left than the start of the chapter name? That is, I don't want any text to be underneath the "Appendix A" part.  I added that red line just to show how I'd like it aligned, if possible.    Here's my MWE:  \documentclass{book} \let\cleardoublepage\clearpage  \RequirePackage{titletoc} \RequirePackage{tikz} \RequirePackage[explicit]{titlesec} \RequirePackage{DejaVuSansCondensed} \RequirePackage[normalem]{ulem} \RequirePackage[   left=2.25in,   right=0.75in,   top=1.25in,   bottom=1.25in,   marginparwidth=1.75in,   marginparsep=.25in,   asymmetric]{geometry}  \renewcommand*\familydefault{\sfdefault} % Set default font  %%% Table of Contents ---------------------------------------------------------- \setcounter{tocdepth}{1} % Show only Chapters and Sections  %%% Change font/color/layout of TOC \makeatletter \titlecontents{chapter}[-2em] {\color{cyan}\bfseries\LARGE\addvspace{3mm}} {\makebox[4.4em][r]{\@chapapp}\contentslabel{-0.25em}\hspace{1.9em}} {} {\hspace{3em}\contentspage} \g@addto@macro{\appendix}{%   \addtocontents{toc}{\protect\renewcommand*{\protect\@chapapp}{\protect\appendixname}}% } \makeatother  \titlecontents{section}[5.3em] {\color{cyan}\large\itshape\addvspace{3mm}} {\contentslabel{0em}\hspace{3.2em}} {} {\hspace{3em}\contentspage} [\addvspace{0mm}]  %%% Chapter Header ---------------------------------------------------------- \makeatletter \titleformat{\chapter}   {\normalfont\sffamily\Huge\scshape}   {}{0pt}   {\thispagestyle{empty}    % Remove page number on new chapters   %\setcounter{definition}{0}   \begin{tikzpicture}[remember picture,overlay]     \node[yshift=-3cm] at (current page.north west)       {\begin{tikzpicture}[remember picture, overlay]         \draw[fill=cyan] (0,-1) rectangle           (25cm,3cm);         \draw[fill=cyan] (0,-24) rectangle           (25cm,-25cm);         \ifttl@label% <---------------------- Added condition on \ifttl@label           \node[anchor=west,xshift=.21\paperwidth,yshift=-.01\paperheight,rectangle]               {\color{white}\LARGE \MakeUppercase{\@chapapp} \Huge\thechapter};         \fi% <------------------------------- end condition on \ifttl@label        \end{tikzpicture}       };    \end{tikzpicture}\endgraf   \vskip-.7cm   \color{cyan}\Huge\raggedright\leftskip-1cm    \noindent\MakeUppercase{#1}\endgraf   } \makeatother  \titlespacing*{\chapter}{0pt}{10pt}{0pt}{}  \titleformat{\section}{\color{cyan}\itshape\LARGE}{\llap{\thesection} #1}{1em}{}[\titleline{\color{cyan}\titlerule[1pt]}] \titleformat{\subsection}{\color{cyan}\normalfont\large}{\; #1}{1em}{}  \begin{document}   \tableofcontents   \chapter{Turing Machines}     \section{The Turing Machine}     \section{Variations of the Turing Machine}       %\subsection{Non-deterministic Turing Machines}     \section{The Church-Turing Thesis}   \chapter{Decidability}     \section{The Universal Turing Machine}    \appendix   \chapter{ON COMPUTABLE NUMBERS, WITH AN APPLICATION TO THE ENTSCHEIDUNGSPROBLEM} \end{document}


I'd like to solve this equation:  $$ u_t  = u_{xx} + u_x  $$ for $t>0$ with initial condition: $$ u(0,x) = \cos (2 \pi x) $$ And $1$-periodic, i.e we have that $u(t,x) = u(t,x+1).$ I was going to solve it using separation of variables, but I was thinking another way, namely solving it using a fourier series. I.e, first I assume that $u$ has fourier series expansion: $$ u(t,x) = \sum_{k \in \mathbb{Z}} a_k(t)e^{2\pi ikx} $$ Now, I would like to differentiate the coefficients in the series and set them equal to each other. Something akin to: $$ a_k'(t) = 2\pi ike^{2\pi i k x} ak(t) + (2 \pi ik )^2 ak(t) e^{2 \pi i k x} $$ And then solve for $ak(t)$. Two questions: 1) is this method valid? I.e is it true that the series are equal if and only if the coefficients are? 2) If I can use this method, how do I solve the ODE for $a_k(t)$? Apologies if this is particularly obvious, I have never taken an ODEs class

For $u:\mathbb{R}\times [0,1]$ with boundary conditions $u(0,x)=\cos (2\pi x)$ and $u(t,0)=u(t,1)$.   Solve $u_t=u_{xx}+u_x$.  I had this on an exam and tried to write $u$ as a product of two single variate functions and convert to an ode using the usual methods but things got messy and I couldn't finish. I also tried to write $u$ as a Fourier series in $x$ with coefficients $a_k(t)$ depending on $t$, but this also didn't seem to yield anything.  Is there a more clever way to approach this, possibly with Fourier series? I heard from a friend there may be a Fourier transform method since the equation was "homogeneous in momentum space."   Thanks!


The installation of Ubuntu 14.04.5 server was successfully finished. I type my username and then hit Enter. At the next row Ubuntu requests the password but it doesn't take any input except Return and new row.  I am new on Ubuntu and grateful for any help.

When I'm about to install a program in the terminal it wants the password:  [sudo] password for xxx:   But when I start to type my password nothing happens. What should I do?


It is known that if a set of natural numbers has positive asymptotic density then the sum of the reciprocals of those elements diverge. Let $\{a_n\}$ be an increasing sequence of natural numbers where the density of the set $\{a_n | n\in \mathbb N\}$ does not exist. Can the series $\sum_{i=0}^n \frac{1}{a_i}$ converge? All the examples that I have of sets where the density does not exist do not converge.

In this  to a question about a series, a theorem was stated:     If $A= \{a_i \}$ is a set such that $\sum_{i = 1}^{\infty} \frac{1}{a_i}$ converges, then $d(A) = 0$, where $d(A)$ is the  of the set.   My background in number theory is basically zero and all my attempts to prove this have been utterly unseccessful; would anyone please help me, or at least provide me with a hint to prove it?


(a) Prove that $N \times N$ is a countable set  (b) Let T be the set of two element subsets of N. Prove that T is countable.  This is a question in my exam review package.  I missed the lesson on countable sets and such, proving them seems simple enough (I have what seems to be a decent solution package provided to me by peers), however this question is just all over the place in terms of an explanation.  I'm just wondering if someone could guide me through the explanation of the solution.    Homework question.

How can I prove that the Cartesian product of two countable sets is also countable?


I beat all of the levels in Dungeon Defenders on mixed difficulties and the room upstairs isn't open, what do I need to do to open it?

My friend and I noticed that there seems to be an inaccessible room in the Tavern with something behind it. We saw that there was a Treasure Chest seemingly floating somewhere off the map.     In addition, if you walk up to the second floor of the Tavern and position your camera through the wall just right, you can highlight something called the Defender's Forge.   Confirmation of the speculation was confirmed in the notes for the 7.07 patch, which had a note that said the following:     Moved bonus-item crates back into the main section of the Halloween Tavern, out from the Secret Room.   What is this Secret Room? How do I get there? Do I need to beat the campaign first or something else?


Right now I'm trying to improve the sharpness of my photos, and for that I've checking if my D7000 has some autofocus issues. Therefore I tested my  and my . I figured that the autofocus for both lenses is correct, so I probably have to learn to use it in a better way.  While testing I started to read a little more (eg. ) about the  and I've learned of the sweet point of each lens. But even with optimized condition I encounter a blue and red gradient in the black square of my test photo.  What do you call this gradient and what is it the result of?    Example details of shot with of my 35mm prime; the only after-work I did is to crop and to set the exposure of the images (same style for each photo):    ISO 400 1/60 f/1.8:  ISO 400 1/60 f/5:   ISO 400 1/60 f/8:     You can see the  blue and red gradient or shade I'm trying to learn about even better when you zoom in:   ISO 400 1/60 f/8:

I make many product photos for the company I work for. For this I use Canon 400D with two external flash devices Walimex CY-600K.  I've noticed an interesting effect on many of the photos I take with white background. On the resulting image there is a red/blue area visible between object and the background. The effect is strongest for black objects and also seems too decrease when I make a brighter photo. It is mostly visible only if zoomed in really close and is not a real problem for me as the resolution is quite high and the resulting images are only 500px wide.   I am just curious as to what is causing it exactly.   For the following example photo I used manual mode with these settings: 1/200 F10 ISO200:  .  You can see blue area left from the object and red area right from it. What is causing this?


mLogit is the function for running multinomial logistic regression in R. What if we have random effects (mixed-effects model), what's the adequate function (and package) for this purpose?

I want to estimate a multilevel multinomial logit model but I am struggling with the terminology and notation used by the R-package MCMCglmm. There is documentation available in form of a  and . According to the article, "the [MCMCglmm] syntax used to specify the model closely follows that used by asreml" (Hadfield 2010: 6). Consequently, some abbreviations like us="unstructured" and idh="independent heterogeneous" are never stated explicitly in the MCMCglmm documentation, although they are well presented in formulas. Unfortunately, I am only acquainted with the notation for hierarchical models in the social sciences and I have no experience with ASReml.  The examples of multinomial multilevel models in the MCMCglmm course notes are subsumed under multiresponse models and the course notes (p. 91) show that trait is used as identifier when the dataset is reshaped for estimating multiresponse models.   Is it necessary to use trait in the fixed (or random) formula also for models with a nominal outcome variable like employment status or gender (in contrast to a real multiresponse variable)? Does the inclusion of trait change the estimated formula or is it only a signifier for MCMCglmm to expect reshaped data? Can I define the error structure without using trait, e.g. by specifying the error structure for coefficients from the fixed part?   Here is an (almost working) example code using a typical social science survey dataset:  library(nnet) library(MCMCglmm)  # Load dataset from TraMineR-package data(mvad, package="TraMineR")  ### Create variable "region" for 2nd level attach(mvad) mvad$region[Belfast=="yes"] <- "Belfast"     mvad$region[N.Eastern=="yes"] <- "N.Eastern" mvad$region[Southern=="yes"] <- "Southern"     mvad$region[S.Eastern=="yes"] <- "S.Eastern" mvad$region[Western=="yes"] <- "Western" detach(mvad)  # Add identifier for complete cases  mvad$complete <- complete.cases(mvad[, c("Jul.93", "male", "Grammar",                                           "gcse5eq", "funemp", "region")])  # Multinomial logit model without random effects using nnet-package multinom(Jul.93 ~ male + Grammar + gcse5eq + funemp + region,           data = mvad[mvad$complete==TRUE, ])  # Multinomial logit models with random effects using MCMCglmm mod1 <- MCMCglmm(Jul.93 ~ trait + male + Grammar + gcse5eq + funemp,                 random = ~ region, rcov = ~ us(trait):units,                 family = "categorical", verbose=FALSE,                 data=mvad[mvad$complete==TRUE, ]) # Including trait and defining rcov gives an estimable command  mod2 <- MCMCglmm(Jul.93 ~ male + Grammar + gcse5eq + funemp,                  random = ~ region, rcov = ~ us(trait):units,                  family = "categorical", verbose=FALSE,                  data=mvad[mvad$complete==TRUE, ]) # Command works as well, but is trait now only used for the error terms?  mod3 <- MCMCglmm(Jul.93 ~ male + Grammar + gcse5eq + funemp,                  random = ~ region,                  family = "categorical", verbose=FALSE,                  data=mvad[mvad$complete==TRUE, ]) # Command does not work as definition of error structure using e.g. "us(trait):units" is needed.    Reference: Hadfield, J.D. (2010) 'MCMC Methods for Multi-Response Generalized Linear Mixed Models: The MCMCglmm R Package', Journal of Statistical Software 33(2): 1–22.


Chrome doesn't seem to clear session cookies when I close my browser. I don't particularly mind this, but sometimes (particularly when testing something), it's useful to be able to clear them out.  Is there a relatively easy way to clear just the session cookies? Ideally I'd be able to do it just for a particular site, but if there's a simple way to clear session cookies for the whole browser instance I'd be fine with that too.

I'm using Google Chrome and want to delete the current session data on the fly. I can do this on Firefox with the web developer extension, but Chrome doesn't seem to have the same option in their webdev extension. So how can I do this?  I realize that session data is stored on the server side and tracked in the browser with cookies. So really, I think what I want to do is delete cookies that are set to live for the session lifetime. Is there a way to do THAT in Chrome? "Delete browsing data" lets me delete all cookies from within a certain time period (for example, the last hour), but that could delete OTHER cookies on the site that I don't want to erase. I just want to delete the cookie being used to track my current session.  To be even more clear: In Firefox, with the web programmer extension installed, I can log into a site, choose "clear session cookies" and just the PHPSESSID cookie is erased. However, other cookies for that domain are not erased or otherwise touched. I want to be able to do this exact same functionality in Chrome.  Thanks y'all...


I wish to use protrusion and expansion from microtype as I like the look you get with them. I use amsthm and typeset theorems in italic as usual (with \theoremstyle{plain}). With microtype enabled, LaTeX fails to break some lines where the last item on the line is something in italic. I get three failures to break nicely with my included example.  I have microtype 2.5 and use lualatex with Latin Modern Roman. I have a working example, though it's not very minimal. If I remove much more the ancillary changes to formatting hide the problem I suspect is a bug. The issue doesn't seem to be with the fact I'm using hyphenated words like Erdos-Hajnal, since the line break failure also occurs on other lines, and problems even occur in my bibliography where some portions of the reference text are in italics. The problem also occurs for me if I remove the \usepackage{fontspec} line. If I remove that line and compile with pdflatex there are no problems.  (Fairly) Minimal Example:  \documentclass[a4paper,twoside]{scrartcl}  \usepackage[UKenglish]{babel} \usepackage{amsmath,amsthm} \usepackage{fontspec,blindtext} \usepackage[babel,protrusion=true,expansion]{microtype}  \theoremstyle{plain} \newtheorem{thm}{Theorem}[section] \newtheorem{prop}[thm]{Proposition} \newtheorem{conj}[thm]{Conjecture}  \begin{document} \begin{conj} For all graphs $H$ there is an $\epsilon > 0$ such that for all sufficiently large $n$, and for all $G\in\mathcal{G}^n$ either $H$ is an induced subgraph of $G$, or $G$ contains a homogeneous set of size at least $n^\epsilon$. \end{conj}  \begin{prop} A short dummy paragraph.   Let $\epsilon_2=\delta\epsilon_1$, where $\delta<1/(2k+1)$. Then there exists $n_0$ such that all graphs on $n\geq n_0$ vertices which do not contain homogeneous sets of size $n^{\epsilon_2}$ have $H$ as an induced subgraph. That is, $H$ has the Erd\H{o}s-Hajnal property. \end{prop}  \begin{thm} Let the graphs $H$ and $F$ have the Erd\H{o}s-Hajnal property, and let $V(H) = \{v_1,\dotsc,v_k\}$. Then $H(F, v_2,\dotsc, v_k)$ obtained by substituting $v_1$ for $F$ also has the Erd\H{o}s-Hajnal property. \end{thm} \blindtext \end{document}   EDIT: this is clearly nothing to do with amsmath, and a simple way to reproduce a similar italic-linebreaking problem is with:  % !TEX TS-program = lualatex \documentclass{scrartcl} \usepackage{fontspec} \usepackage[UKenglish,latin]{babel} \usepackage{microtype} \usepackage{lipsum} \begin{document} \lipsum[1-2] \textit{\lipsum[1-2]} \end{document}

Please see the following screen shots.    As you can see there are two "overfull" hbox there. However, LaTeX does not produced any overfull box warning at all. I tried to produce a minimal working example but without exactly the same layout, and fonts, and line breaks, it cannot be reproduced. So sorry that I cannot include a MWE in this question. (edit: please find an MWE further down).  However I tried to diagnose the problem. Since LaTeX does not see these as overfull box, it could be protrusion problem I guess. I setup the Minion fonts with fontspec (LuaLaTeX) as following,  \setmainfont[ UprightFeatures    = {RawFeature = {protrusion = mnr}}, BoldFeatures       = {RawFeature = {protrusion = mnr}}, ItalicFeatures     = {RawFeature = {protrusion = mni}}, BoldItalicFeatures = {RawFeature = {protrusion = mni}}, RawFeature = {expansion  = default}, Ligatures = {Required, Common, Contextual, TeX}, Numbers = {OldStyle, Proportional}, SizeFeatures = {   {Size =      -8.41,  OpticalSize = 8},   {Size =  8.41-13.01, OpticalSize = 11},   {Size = 13.01-19.91, OpticalSize = 19},   {Size = 19.91-,      OpticalSize = 72}}, ]{Minion Pro}   Ignoring the other things (for example the SizeFeatures is used to work around the problem that fontspec/luaotfload cannot select the right optical sizes). The problems appeared to the line  ItalicFeatures = {RawFeature = {protrusion = mmi}},   Where protrusion is turned on before the fonts setup by \pdfprotrudechars2 and mni is the protrusion setting for Minion Pro Italic. I translated the setting in MinionPro package to be used with LuaLaTeX (as the official release of microtype do not support LuaTeX with opentype fonts loaded by fontspec yet). A portion of the Lua file that setup the protrusion can be found below,  fonts                    = fonts                    or { } fonts.protrusions        = fonts.protrusions        or { } fonts.protrusions.setups = fonts.protrusions.setups or { }  --omitted codes--  fonts.protrusions.setups["mni"] = { -- Minion Pro Italic        factor = 1, left = 1, right = 1,    -- omitted code--   [0x0067] = {-0.070, -0.070}, -- g   [0x0069] = { 0.000, -0.110}, -- i   [0x006A] = {-0.090, -0.150}, -- j   [0x0070] = {-0.040,  0.000}, -- p   [0x0072] = { 0.000,  0.080}, -- r   -- omitted -- }   I I change the protrusion factor of letter g and p, which are the breaking points in the picture above, then the problem solved.  Can anyone explain the problem? Is there something wrong with my fonts setup (the use RawFeatures) or the protrusion setup file (the codes omitted in the above code snipes are just setting for other letters, which I assume should be independent from each other)?  It seems that whenever a linebreak happens at a italic character and protrusion is activated for that character, then the problems always happen. This does not happen for roman fonts.  Edits: Further experiments showing that assigning positive values instead of negative values to the protrusion factors does not cause any problem for the italic fonts. I guess the problem is not with Italic font, but with the negative value of protrusion factors. The reason no such problem for roman fonts is that there are no negative values assigned for any roman characters. But some italic characters has negative protrusion values so that they don't reach out the boundary too much.  Latest Edit: Here's a minimal document that triggers the issue.  \documentclass[a4paper]{article} \usepackage{microtype} \usepackage{amsthm} \newtheorem{proposition}{Proposition} \usepackage{lipsum} \begin{document} \begin{proposition}   \lipsum \end{proposition} \end{document}   With lualatex (showcases the bug):  With pdflatex (perfectly fine):


I'm using Skype (not for Business) on Windows 10. I want to export my chat logs to a text file. I read  and other posts which say I should look in %appadata%\Skype.  But all this folder contains is RootTools\roottools.conf. There is no user folder in there. Where are my chat logs?

Where and how can I view my skype logs (Chat and Voice history)? Does it get saved somewhere in PC by default? Can I choose a folder location myself to start saving voice and chat history?


I'm flying to the US in June for a total of 67 days in order to visit my girlfriend. I would have liked to stay the full 90 days but I've had to book an earlier return flight so I can come back to the UK to take an exam resit at my university. After the two week exam period, however, I have approximately another month before I have to start back at university.  Would flying back home after such a long stay in the US only to return 2 weeks later put me in danger of being denied entry at border control? I thought maybe if I was able to explain the reason for my return home and provide evidence that I'm starting back at university again, I'd be ok, but I don't want to jeopardise future trips to see my girlfriend just for the chance to spend a few extra weeks with her.  To complicate matters further, I've recently applied for the Global Entry program and am hoping to be approved before I leave the US. Would being a Global Entry member guarantee that I'd be able to return after my exam resit or would I still be taking a risk?  Thanks for your help.

I am a British citizen visiting the USA in early August for a two week vacation with friends. After the holiday I'm returning to my home in the UK for three weeks. After that I will return to the USA and will be working for my British employer under the Visa Waiver Program for a period of 80-85 days.  I have read already that there is technically no problems with this under ESTA rules, but should I limit this working period to a shorter time frame (e.g. 70 or so days) so that it does not negatively affect the decision made by the POE officer? Ideally I would love to be over in the states for the near-full 85 day period.  Any advice or previous experiences anyone can offer?  Some clarifications: As confirmed by the immigration attorney, as I am employed by my UK employer, it will be regarded as a business trip, the important part being that I will be working officially as a consultant for my UK employer just overseas for the allotted 85 or so days


I was wondering if the No Free Lunch (NFL) theorem applies to even the estimation problem. Suppose there are $N$ points in the input. We are trying to estimate the mean value say weights associated with the $N$ points. By randomly selecting $n$ of the $N$ points, we obtain an unbiased estimate of the population mean weight.   However, the NFL states that the knowledge of the $n$ doesn't imply the goodness of the estimate of the remaining $N-n$ points. Does this mean there is no best estimator of the population mean in statistics?  I will also be very grateful if someone could share some papers on NFL in sampling and statistics since I haven't been able to find them yet.     Clarification: I asked this question in maths forum but didn't get any answers, so I am re-posting it here.

A woman I was working for asked me to do a one-way ANOVA on some data. I replied that the data were repeated measures (time series) data, and that I thought the assumption of independence was violated. She replied that I should not worry about the assumptions, just do the test and she would take into account that the assumptions might not have been met.  That did not seem right to me. I did some research, and found this wonderful blog post by David Robinson, , which exposed me to the No Free Lunch Theorem. I have looked at the original paper and some follow on stuff, and frankly the math is a bit over my head.  The gist of it -- according to David Robinson -- seems to be that the power of a statistical test comes from its assumptions. And he gives two great examples. As I wade through the other articles and blog posts about it, it seems to always be referenced in terms of either supervised learning or search.  So my question is, does this theorem apply to statistical tests in general? In other words, can one say that the power of a t-test or ANOVA comes from its adherence to the assumptions, and cite the No Free Lunch Theorem?   I owe my former boss a final document regarding the work I did, and I would like to know if I can reference the No Free Lunch Theorem in stating that you cannot just ignore the assumptions of a statistical test and say you'll take that into account when evaluating the results.


In Blade Runner 2049, when K is walking through the ruins of Las Vegas, he finds a small honey farm--overcrowded, swarming with the bees, as if not touched very often.  The film as it unfolds after that, never explains that scene.  Deckard was clearly the only person living in Vegas at the time; is he farming honey just to nourish himself in that wasteland town?  Or is there some broader artistic reason for the swarming bugs?

I watched Blade Runner 2049 and while it was gorgeous there were a few things that left me scratching my head:  In one scene, K (Ryan Gosling) is walking through Las Vegas and find a dozen apiaries full of bees. The scene is beautiful, but never explained. I can't imagine that such a detailed movie with so much thought given to each shot has this for no reason. What's the meaning of this scene?


if G is free group of rank >1 , Show that the commutator [G,G] has infinite rank. Please help, I tried to find an expression of the commutator but I have no idea

I'm having trouble with this exercise:     Let $G$ be the free group generated by $a$ and $b$. Prove that the commutator subgroup $G'$ is not finitely generated.   I found a suggestion that says to prove $G'$ is generated by the collection $\{[x^m,y^n]\mid m,n\in\mathbb{Z}\}$. I don't know how to prove this, and how it helps.  If you could please provide me with some hints... Thanks!


Here it is the screenshot, clicking on the ballot there appears the annotation. I already tried okular but I'm not able to reach the same result (actually to save annotation I have to export the pdf as Document Archive, which makes it unreadable for every other pdf reader)    I opened it with Document Viewer

Currently I need to highlight certain sections in PDFs, or add annotations (comments/notes). These modifications would need to be saved.   What tools are out there to do this on Ubuntu?


Science fiction novel where aliens give up invading Earth after experiencing severe weather in US (Tornado Alley/hurricanes?). I think I read it before 1990. Some small chance has Red Cross symbol on a structure’s roof on the cover.

I'm trying to identify a short story I read within the last two years about aliens who invade Earth while the Cold War is occurring.  They are baffled by the strange white stuff that falls from the sky and freezes them, the moving winds in the tropics that destroy their bases and other aspects of climate.  The aliens focus their attack on the United States, but all Earth unites to fight them off, being ultimately unsuccessful.  The aliens build their base on an uninhabited island to sign a treaty with Earth, where it is agreed that Martians will inhabit the Earth for the six months each year where it's not snow season or hurricane season.  It is revealed at the very end that the uninhabited island the aliens have built their base on is      Krakatoa.   The story is told primarily from the alien war general's point of view, and may have been a Baen story.  (Even though I read it in the last two years, I got the impression that it was a lot older - publish date probably sometime in the last millenium).


I've seen the words        plan -> planned, planning   begin -> beginning      Why is "happen" different and why is "happenning" an incorrect spelling?

The past tense of to occur is occurred (not occured), but the past tense of to listen is listened (not listenned).  Why? What is the general rule that is applied to make the past tense of a verb?


How many significant figures should one give in stating a experimental uncertainty? For this purpose I found three rules:      Experimental uncertainties should be always stated to 1 significant figure.   For example: $3.45 \pm 0.015$ should be $3.45 \pm 0.02$ [].    The number of significant figures in the experimental uncertainty is limited to one or (if the uncertainty starts with a one, e.g., ± 0.15) to two significant figures.   For example:  $3.45 \pm 0.015$ should be $3.45 \pm 0.015$ [].    One significant figure should be used to report the uncertainty or occasionally two, especially if the second figure is a five.   For example: $3.45 \pm 0.035$ should be $3.45 \pm 0.035$ [].

I was doing some exercises on error propagation when I came across this problem:  $4\pi^2/(0,034 \pm 0,004 \space s^2/cm)$  I calculated my uncertainty to be $\Delta$ = 136 $cm/s^2$  And so the hole thing gives me: $(1200 \pm 136) \space cm/s^2$.  Now going into my question I rounded $4\pi^2/0,034 = 1161.12993$ to $1200$ which makes sense since my uncertainty is 136 but in the solution to this problem $136$ is rounded to $100$ and that's not making much sense to me.  So should I always round my uncertainty to the nearest hundred (assuming my uncertainty has 3 digits)?


I would like to add a detailed link in specific cells in a dynamic table in JQuery.  This code works fine when adding a cell/row :  $('<td class="ploegen-details-naam" onclick="link_naar_info_speler(this.parentNode.childNodes[0].textContent)">    </td>').text(speler_naam).appendTo(details_rows);   But if I want to add dynamically detailed id's to the cell, this does not link anymore:  for (var x = 0; x < len; x ++) {    $('<td>', {id:"naam_thuis" + x}, {class:"ploegen-details-naam"},   {onclick:"link_naar_info_speler(this.parentNode.childNodes[0].textContent)"}).text(speler_naam).appendTo(details_rows); }    This function is exactly the same for the 2 examples :  function link_naar_info_speler(speler_id)  {     location.href="/ADL/Info/Spelers/Spelers.html?" + speler_id; }   The part that doesn't work in the second example is the onclick with the link. I only posted the relevant code, since the rest of the code is the same in the 2 cases.

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


I know that i can make two columns unique keys, but that's not exactly what i want.  I want that for example if col1='1', col2='2' then there can't be another row with col1='1', col2='2', but totally possible to do the following:  +--------+--------+ |  col1  |  col2  | +--------+--------+ |    1   |    1   | |    1   |    2   | |    2   |    1   | |    2   |    2   | +--------+--------+   while this is impossible:  +--------+--------+ |  col1  |  col2  | +--------+--------+ |    1   |    1   | |    1   |    1   | +--------+--------+   Making both unique keys is not an option as in col1='1', col2='1' and col1='1', col2='2' col1 is the same and that's not allowed if both are unique keys.

I have a table:  table votes (     id,     user,     email,     address,     primary key(id), );   Now I want to make the columns user, email, address unique (together).  How do I do this in MySql?  Of course the example is just... an example. So please don't worry about the semantics.


I recently got a PS4 and I was wondering if I could play games like GTA:V with my PS3 friends? I'm thinking that you can't but wanted to confirm. I tried playing with them but it says that they aren't playing GTA:V.

Grand Theft Auto Online exists on five different platforms: XBox 360, PS3, XBox One, PS4, and PC. Do any of these play on the same servers, allowing people on differing platforms to play together?


My question is that ,what is the diffrence between limit and limit point?

I understand that similar questions to this have been asked  and  but I believe my question is different because with regards to (1) I am not asking about the set $X$ that contains the points of my sequence and with regard to (2) because I have the distinct definitions of limit and limit point in mind. That said:  My Question: My textbook, Fundamental Ideas of Analysis by Michael Reed, defines a limit point as:     Definition: Let $(a_n)$ be a sequence of real numbers. A number $d$ is called a limit point if, given $\epsilon > 0$ and an integer $N$, there exists $\color{red}{\mathrm{ an }} \ n \ge N$ so that $|a_n - d| \le \epsilon$.    The definition of a limit is as follows:     Definition: We say that a sequence $(a_n)$ converges to a limit $a$ if, for every $\epsilon \ge 0$, there is an integer $N(\epsilon)$ so that $|a_n - a| \le \epsilon \color{red}{\text{  for all  }} n \ge N$.    From these definitions, and given this question:     If a sequence converges it has exactly one limit point. Is the converse true? If not, provide a counterexample   Can I conclude that the converse is indeed true simply by appealing to the definitions, or do I need a tighter proof. And if I do, I'm a little stuck on how to refine this proof.


I have written the following code  \newpage \begin{figure}   \centering   \includegraphics[height=\textheight]{my_fig}   \caption{My caption}   \label{fig:my_fig} \end{figure}  \newpage \bibliographystyle{splncs03} \bibliography{my_bib}   The image covers an entire page. When I compile my document, the image comes after the bibliography and I receive the following warning   LaTeX Warning: Float too large for page by 22.75pt on input line 221   I want the image to be put right before the bibliography. How can I do it? I already tried with the options [h] and [!h]. Consider also that I am using the llncs style.

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 have just added the Mate Desktop repository with this command: sudo add-apt-repository "deb http://packages.mate-desktop.org/repo/ubuntu quantal main"  I have quite a few repositories installed, and running sudo apt-get update can take quite some time. I have heard of ways to update a specific ppa, however, the solutions don't work with a repository added through it's deb repository line.  Is there any way that I can choose to update only one non-ppa repository?

When I add a PPA and I want to install some of its content, it is quite annoying to re-update all my apt list using apt-get update.  Is it instead possible to only sync the content of a given repository?


Prove if $A$ is a finite set and $B$ is infinite then $|A|+|B|=|B|$  My work  I was thinking in solve this exercise by contradiction.  Suppose $|A|+|B|\not = |B|$ then $|A|+|B|=|A|$  Here im a little stuck. Can someone help me?

I'm studying logic and unfortunately, I'm a newbie at this, so I don't see the stuff everyone sees at the moment. I want to solve following exercise, but get nowhere:      Let $A$ be an infinite set and let $B$ be a finite set. Use the AC to   prove that $|A| +|B| = |A|$.   I've proved this one though:      If $X$ is an infinite set, there is an injective function $\mathbb{N}  \rightarrow X$, hence $\omega \leq |X|$.   But I don't see how I could use this. What's the logic here?


I'm trying to make a python program for a given software than will scan&run another certain python function at choice (or .py file altogether). However I can't import a function name set in a variable.  import glob  functions_list = glob.glob('*.py') #all my python files are found #pick any specific file to import import a[3]   This fails with SyntaxError: invalid syntax.  Is there any way to do this? My idea is to have a TkInter selection list where I click to run the .py I selected.

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


I am using a chemical notation repeatedly so made this new command  \newcommand{\MolCState}{$\text{C}^3\Pi_u$}   The problem is that in the text when I type   \MolCState and the rest of the text   the output is like    there is no space before "and". Why is this different than typing   $\text{C}^3\Pi_u$ and the rest of the text   where space is there without adding anything?

How can I define my own shorthand command, but making sure that the spacing afterwards is correct?  \newcommand{\abc}{\textsc{abc}} produces 'ABC,' but has the problem 'ABCmoretexthere' (i.e. no space before the next word).  Vice versa  \newcommand{\abc}{\textsc{abc} } produces  'ABC moretexthere' but has the problem 'ABC ,' (i.e. one space before the comma).  How can I make both work?


I have more than a hundred encrypted procedures and functions that I want to decrypt. I tried using  decryption wizard for in place alter but I get the error "Definition is invalid. Can't find CREATE keyword". When I try to see the DDL script of a stored procedure, I get the error "A definition for the object dbo.pt_blocks cannot be shown because it is enrypted by a third party tool" I can not find a resolution to this. Are there any solutions or other tools available for this? Edit: I found  which mentions "take the source code and issue an ALTER command without the encryption option. Just take the source code and remove the WITH ENCRYPTION" How could I achieve this?

I am working on a third party database.  When I try to view the definition of a view by right clicking, CREATE TO and then to NEW QUERY EDIT WINDOW, I am getting an error:     This property may not exist for this object or may not be retrievable   due to insufficient access rights. The text is encrypted.


Why simple harmonic motion time period equation is independent from displacement from mean position?

I'm looking for an intuition on the relationship between time period and amplitude (for a small pertubation) of pendulums.  Why does the period not depend on the amplitude? I know the math of the problem. I am looking for physical intuition.


I have a WORKORDER points FC that has a CLASSIFICATION field (Oracle 18c/10.7.1 GDB). I want to automatically/programmatically create a dynamic layer in ArcGIS Desktop 10.7.1 for each unique value in the CLASSIFICATION field in the FC. In other words, if there are values like POTHOLE, SIDEWALK GRIND, STM POND CLEANING in the CLASSIFICATION field, then I want to create separate layers that only include features where the CLASSIFICATION is:  POTHOLE (layer name is POTHOLE) SIDEWALK GRIND (layer name is SIDEWALK GRID) TREE PRUNING (layer name is TREE PRUNING)  And I want to make the symbols for each layer to be the same—a simple point that is a specific colour.  What would it take to automatically generate the layers from a field in ArcGIS Desktop?

I am trying to set multiple definition queries for one layer based on one field using python.  ie.  I have a City layer with a field that holds the city name.  I want a copy of the layer in an MXD with the Definition query set for each value in the City field.  So essentially, I have one source layer, with a copy of the layer as many times as there are values in the City field.  The query would look like this: CITY = 'Atlanta'


I'm trying to remember the author and title of a short story about the Earth in the far future which is visited by an enormous creature (maybe like a continent sized salamander) which devastates the world but is worshipped by the people. It returns periodically with earth-shattering consequences. Any ideas?

I was looking for a short story I read a while ago but I think is an old scifi story (maybe from the 1960s). It's about some sort of space creature that resembles a lizard that jumps from deeper space to the Earth. The monster is big enough to sit over half the world and it seems invulnerable to any kind of attack. If I remember right, at the end of the story the creature just jumps leaving an almost destroyed planet behind.


If I have two s in play, can I use the ability of one to affect the other?  For instance, if one of my Skinshifters has  on it, can I use the other Skinshifter's ability to morph the "caged" one, thereby breaking the Ice Cage?

Many abilities in MTG use a permanent's name in the ability. Does this mean that if I have 2 copies of that permanent, the ability will affect both permanents?  Activated ability example:  - If I activate the ability of one of my Vector Asps, can I choose which of them gain infect until end of turn? Or will they both gain infect?  Triggered ability example:  - If I cast a second Sin Collector, when it enters the battlefield, will each Sin Collector trigger and allow me to exile a total of 2 cards instead of 1?


I often hear people (mostly English learners) asking "How to ... ?"  I think it is incorrect.  But has this form of questions been accepted in contemporary spoken English?  An example:  A: "Can I have your name, sir?"  B: "My name is John Schwarzkopf."  A: "How to spell your last name?"  B: "S-C-H-......"

On the other hand  that fix mistype in "How to" got though community approval.  What is the rule about "How to" and "How do I"? Why are some tutorials called "How to"s?


My lap has the spec of 1.90GHz I3 4030U Intelcor  but advised is 2.0 dual-core. can my lap install Ubuntu latest version and work normaly in same fast? I want it for studio purpose like design, graphics, editing, photograph etc..

I'm thinking about installing Ubuntu Desktop, but I don't know what flavor is the best for my system. What are the minimum and recommended hardware requirements? What kind of CPU? How much memory? Should I have Hardware Acceleration? What flavor should I use?  This is an attempt of a canonical answer. My answers have the "official  requirements", the recommended are a mix of official sources and opinion based (along with the answer it's told the source). You can comment or edit if you feel that the information is obsolete or incomplete. It is a good rule of thumb that any system capable of running Windows Vista, 7, 8, x86 (Intel) OS X will almost always be a lot faster with any Ubuntu flavor even if they are lower-spec than described below.


Background I'm reading A Midsummer Night's Dream, and a lot of the dialogues and monologues are rhymes. But some times, these rhymes aren't rhymes at all. For instance  So should the murder'd look, and so should I, Pierced through the heart with your stern cruelty  A bit of a stretch to say the least. There are also cases where the written words end similarly, but spoken, they do not.  About the wood go swifter than the wind, And Helena of Athens look thou find  Question Did these word pairs ever rhyme? Was the state of the language ever such that these lines would be spoken on stage and rhyme perfectly? With "I" and "cruelty", one could pronounce the latter "cruel-tie", and I wouldn't scoff at the idea that this may have been common at some point. EDIT The I/cruelty rhyme is perfectly explained in another Q&A:  The same question still remains for the wind/find rhyme.

Either "wɪnd" or "waɪnd" is acceptable, according to , but merely being acceptable doesn't satisfy me. "Wɪnd" seems better to me, due to the connotation of blowing wind, etc, but apparently "waɪnd" is preferred, being listed first.  Which was originally intended?  (Or does it really not matter?)


I'm feeling confused. If I square 1 and -1, the answers should be equal:  $1^2 = (-1)^2$  Then I take both sides to the power of $\frac12$:  $\left(1^2\right)^\frac12 = \left((-1)^2\right)^\frac12$  This next step seems to make sense according to the simple arithmetic rule about multiplying exponents:  $1^\left(2\cdot\frac12\right) = (-1)^\left(2\cdot\frac12\right)$  And then comes the weirdness:  $1^\left(\frac22\right) = (-1)^\left(\frac22\right)$  $1^1 = (-1)^1$  $1 = -1$  Obviously I did something wrong... Every step seems perfectly reasonable except going from step 2 to step 3. That seems reasonable too, that's what I was taught about exponents, but that's the only step which I could conceive has special constraints I violated. Is $\left((-1)^2\right)^\frac12 = (-1)^\left(2\cdot\frac12\right)$?

What is the condition for $(\text{number}^c)^b=\text{number}^{cb}$ to be true?  I can't find it on google.ze so I asked it here on math.stackexchange.com.


I'm trying to remove a row based on the id but i keep getting a NullPointerException.  My code:  public void removePatientsFromDatabase(int id) {     String removeSql = "DELETE FROM patienten WHERE idPatient id = idn";     try (Connection con = sql2o.open()) {         con.createQuery(removeSql)                 .addParameter("idn", id)                 .executeUpdate();     } }   The error:    The database:

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


There seems to be a difference between main(String[] args) and other string arrays that i can not figure out, my example.  public class TestArgs  { public static void main(String[] args) {     String[] x = {"1","2","3"};     System.out.print( x[2] == "3" );     System.out.print( args[2] == "3" ); }}   I run this program as:  java TestArgs 1 2 3   I would expect the output to be "truetrue" but instead I get "truefalse"  Could someone please tell me what the difference is, or am I just doing something really stupid...

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?


How can you show that if $p$ is prime then the numbers with maximum possible order modulo $p^2$ is $\phi(\phi(p^2))$.  I tried finding order(a) modulo 9, and obtained the following: $1$ is $1$, $2$ is $6$,$3$ doesn't exist, $4$ is $3$, $5$ is $6$, $6$ doesn't exist, $7$ is $3$, and $8$ is $2$.  So maximum possible order is 6, and 2 and 5 have maximum possible order. Also $$\phi(\phi(3^2)) = \phi(6) = \phi(2)\phi(3) = 2$$ and so I verified that this is true. Now how do I go about proving the statement? Where do I even start?

Prove if $n$ has a primitive root, then it has exactly $\phi(\phi(n))$ of them.   Let $a$ be the primitive root then I know other primitive roots will be among $\{a,a^2,a^3 \cdots\cdots a^{\phi(n)} \}$ because any other number will be congruent modulo $n$ to one of these. Then I figured as the answer is $\phi(\phi(n))$ so for $a^k$ to be primitive root, $k$ must be coprime with $\phi(n)$.But I don't know the reason.Am I missing any silly point?


I created a blog via Github Pages and as I started writing articles I wanted to check if it was indexed by Google. The blog is:  After a few weeks I manually added it to Google Search Console. Then, in a day or two, it displayed only one page () which is a repo page, but seemed to totally ignore the main blog pages. I noticed my sitemap had not been fetched so I added it manually. Waited again a week or two and still no luck. Google still displays "Unable to fetch sitemap" (well, something like that, my Google is not in english) next to it. My sitemap () is generated by the jekyll plugin and looks good to me. Robots.txt () do not seem to be the problem either. So, now my Google Search is still empty except for this repo page mentioned earlier. Maybe I should wait longer, I did wait 1~2 months already though. Have you had any similar experience or have any idea I could try ? Thank you for your time !

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


Apparently radioactive decay cannot is entirely random (I'm just picking something that's currently accepted as random). However, since it's caused by something, if you had the means to do so, surely you could be able to successfully predict when radioactive decay in an atom will occur, since it has a cause?   I like to think of it like this: if the universe were to somehow be recreated with PRECISELY the same properties, down to the smallest level possible, that this universe had at its beginning, then wouldn't every play out the same- any I mean everything?

I'm not sure if this is the right place to ask this question. I realise that this maybe a borderline philosophical question at this point in time, therefore feel free to close this question if you think that this is a duplicate or inappropriate for this forum. Anyway, I'm an electrical engineer and I have some basic knowledge of quantum mechanics. I know that Schrödinger's equation is deterministic. However, quantum mechanics is much deeper than that and I would like to learn more. If this question is not clearly answerable at this point than can anyone point out some recognized sources that try to answer this question. I would appreciate it if the source is scientific and more specifically, is related to quantum theory.


On , it says that you can change Fullscreen permissions.  However, when clicking the permissions, I can only change to allow on this page or ask:    I want to be able to always allow on any site, like some other permissions have:    Is this possible? I also want to get rid of this:

Every time I switch into Full Screen (F11) in chrome it says "You've gone full screen. Exit Full Screen (F11)".   Can I disable this from showing up? I know how to exit full screen.


How can we derive these two equations  $\sum{\binom{n}{i} \times 2^{n-i}}=3^{n}$  $\sum{i \times \binom{n}{i} \times 2^{n-i}} = n \times 3^{n-1}$  The second equation can be related to the following problem: You have $n$ balls and you can color each ball red, green, or blue. There are $3^n$ possible ways to color the balls. Among all possible ways, how many times we can get a ball of the color red.  If we select $i$ balls from $n$ balls and color them red and color the remaining balls either blue or green, we can get ${i \times \binom{n}{i} \times 2^{n-i}}$ red balls for all possible ways selecting $i$ red balls each time.  How can we derive the equations?

I want to prove the following equality:  $$\displaystyle\sum_{k=1}^{n}k{n \choose k}2^{n-k}=n3^{n-1}$$  So I had an idea to use $((1+x)^n)'=n(1+x)^{n-1}$  So I could just use the binomial theorem and let $$x=2 \implies (n3^{n-1})$$ and then modify the sum into that one on the left side.  So I need to prove that : $$\displaystyle\sum_{k=1}^{n}k{n \choose k}2^{n-k}=n(1+x)^{n-1}$$ if$$x=2$$ Any help would be appreciated.


I have a site where Google has already indexed about 1 million pages, and I want to change all the URL paths for SEO purposes, ensuring that we always have our keywords in the path.  Technically I know how to complete it (301 redirects, new canonical URL, update sitemap, etc.) but I'm wondering if Google will penalize the site because of it, or if links will disappear from search results until they are re-crawled?

I have run a domain for 9 years, which had PR5 two years back with DA 49 (which I remember). Now I have run another domain for 4 years in similar keywords but from a different location (as you can see from the CCTLD).  As my old .np domain is not being useful, I am thinking to redirect it to my new .au domain. Both of them have similar keywords.  Now, my question is: if I do 301 redirection from the old to the new domain, is that going to carry Google penalty with link juice? (I am not sure why PR is down to nothing in two years. I remember it was hacked a few times and I couldn't fix on time.)  The point is I want to take credit of my own domain, which I maintained for almost 9 years and has very good link juice. Saying that, I am very concerned about losing my new domain's SEO value which I have run for 4 years and worked my butt off to bring into good position.  I can't take a risk to experiment at this stage as my business relies on the new domain. Instead, I would like to add some value from my old domain, which can make my life easier.  Thanks for showing interest. I expect to get some expert advice here.


I've upgraded from 19.10 to 20.04 using sudo do-release-upgrade -d (because the new 20.04-version didn't show up with the normal update-manager). Everything's went fine, output from lsb_release -a:  No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 20.04 LTS Release: 20.04 Codename: focal   except that my dash is empty since that upgrade:   My dock is ok, it still shows the applications (I'm using dash-to-dock extension).  Can anyone help me getting back my entries in the dash, please?  I deactivated appfolder-management extension as suggested ; the extension was not active at all, did a reboot -> no success. Then I changed theme from Radiance to Yaru and used Ubuntu for login (as always) -> no success.  Additionally, when I click "Frequent" at the bottom of the application list (to show frequently used applications), the desktop environment briefly crashes.

I did an upgrade today to the latest version of ubuntu. Everything looked good and fine only for me to discover that I cannot find my applications after clicking the 'Show Applications' icon. The same applies when I search for an application in the search bar, I do not see it. It shows me an endless search.  These are the screenshot images of the problem:      In the meantime, I access my applications from the menu at the top bar and also use the terminal to run applications with CLI.


I am using PostGIS on pgAdmin3 (PostgreSQL 9.3 e PostGIS 2.2).  I have a shapefile with more than 500.000 features and I want to merge them into one.   The geometries are MultiPolygon.   I would like to have as output a shapefile with the same geometry's complexity like the input. I Have to simply the geometry after a merge...  I used several codes but none of them seem to work.  All these queries do not return what I would aspect: I have a table with the same number of feature than before.  CREATE TABLE test1 AS      SELECT gid, fid, (ST_DUMP(geom)).geom AS geom FROM land_polygons;   or  CREATE TABLE test2 AS SELECT   1::INT as gid,   ST_Buffer(ST_Collect(geom),0)::geometry(MultiPolygon,4326) FROM   land_polygons;   or  CREATE TABLE test3 AS SELECT gid, fid, ST_GeometryN(geom, generate_series(1, ST_NumGeometries(geom))) AS geom  FROM land_polygons   or  CREATE TABLE test4 AS SELECT ST_Union(ST_SnapToGrid(geom,0.0001)) FROM land_polygons;   I do not know what I could do more...

I have the following layer using SRID 27700 in postgis:    It's every administrative region in the UK, and (as you can see from the colour grouping) each of them has a text field specifying the county they lie in.  What I'd like to do is to make larger county polygons from the smaller ones in a given county, so EG in the picture above all the teal colour polygons would form one large polygon from the single outer ring that contains all the polys in that colour, like wise all purple, brown, pink, grey etc should all form one polygon.  I've already tried the following:  insert into parishesmerged (geometry) select astext(multi(ST_Union(the_geom))) as the_geom from parishes group by county_name   But it keeps generating broken geometries which I then have big problems processing further.  I'm trying to make a simpler county level map with the major output areas in.  Any solutions don't have to be in Postgis either, I have the full OS4Geo stack installed, the latest version of QGis and more utils than I can shake a stick at.  The only things I don't have are the big boys like ArcGis (Although I may have an Old Mapinfo lying around somewhere)    For the record, the dataset I'm trying to create is to accompany a GIS book I'm on writing aimed at .NET programmers wishing to write GIS applications using .NET    After trying the suggestions below, the one that worked the best was 'Paul Ramseys' solution.    I now have a nice simplified counties & boroughs file that's just simple enough for my book, but complex enough to allow me to demonstrate some interesting geo-spatial SQL.  Even though Paul's solution ultimately was the one that worked for me, I also drew on the other answers for things like simplifying the polygon map and reducing the complexity further.  On thing I did observe while doing this however, while ST_Collect is indeed faster than ST_Union, run for run it was also the one mostly responsible for broken geometries.  My guess is the speed increase is obtained at the expense of less accuracy in the core function.


This just started happening today:  I have minecraft installed on Ubuntu 14.04 LTS. For some reason multiplayer doesn't work for me: I get a good ping for the server but every time I attempt to join, for the first few moments everything works and chat is working but then, all the players freeze, chat doesn't work, portals don't work, and when I type something in chat, it doesn't show up. After 5 more seconds, I get kicked from the server and it says "Connection lost Timed Out".   I've tried joining many servers (hypixel, mineplex, etc.) but none of them work (the same thing happens to all of them). I've tried restarting my computer 2 times, disconnecting and reconnecting my wifi, and I re-installed minecraft.   What can I do to fix this?

I can browse the web fine, watch YouTube, listen to music, etc. But when I try to join ANY Minecraft server, as soon as I try to make a connection, I either:  Time out my connection  or:   Sit there waiting for it to load, then disconnect  On Minecraft, it says I have good ping to the server, but then I join it and I lag out as I stated above. I can connect to other servers on other games.. but not Minecraft. I have restarted my PC and my modem, still nothing.  What can I do to solve this issue ?