How can we copy an object in java without copying the reference. If any object is present inside then we should copy the value only with out modifying the original object reference.  How can this be done in a general way. That is we don't know whether the object is serializable or not.  I want to write a method which will deep copy the object passed to it. The object passing to it will be of any type.

It's a bit difficult to implement a deep object copy function. What steps you take to ensure the original object and the cloned one share no reference?


In penalized/regularized regression (lasso, ridge, etc.) the predictors are typically standardized to be centered at 0 and often to have variance 1. Are categorical predictors treated differently. If so, why? What are the consequences of using the same standardization? Is a reference available?

For the LASSO (and other model selecting procedures) it is crucial to rescale the predictors.  The    is simply to use a 0 mean, 1 standard deviation normalization for continuous variables. But what is there to do with dummies?  E.g.  from the same (excellent) summer school I linked to rescales continuous variables to be between 0 and 1 (not great with outliers though), probably to be comparable to the dummies. But even that does not guarantee that the coefficients should be the same order of magnitude, and thus penalized similarly, the key reason for rescaling, no?


Okay, weirdest thing and I can't work it out.  I installed (and purchased) the plugin Seed Pro Coming Soon and built my site. Looks great!  However as soon as I disable this plugin and view my site I get a bunch of errors such as:  ReferenceError: jQuery is not defined  And nothing jQuery related on my internal pages work. Everything on my homepage works perfectly, but any pages inside don't.  Huh? Does anyone have any clues? I need to launch this site and not even the dropdown menu will work!

I'm doing it right now with the following code:   function uw_load_scripts() {     // De-register the built in jQuery     wp_deregister_script('jquery');     // Register the CDN version     wp_register_script('jquery', 'http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js', array(), null, false);      // Load it in your theme     wp_enqueue_script( 'jquery' ); } add_action( 'wp_enqueue_scripts', 'uw_load_scripts' );   This works, but should I do this for everyone, like this, or for everyone but admin (so that backend uses the WordPress version?):  if (function_exists('load_my_scripts')) {   function load_my_scripts() {       if (!is_admin()) {       wp_deregister_script( 'jquery' );       wp_register_script('jquery', 'http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js', array(), null, false);      wp_enqueue_script('jquery');        }   }   }   add_action('init', 'load_my_scripts');   This version doesn't work at all actually, I get the WordPress jQuery-version and not the Google one.  Therefore, should I deregister the jQuery that is included in WordPress at all?    Also, how do I add my own scripts (slider scripts, modernizr and my own custom.js) the correct way? I guess I should do this via functions.php as well and not in the header like I'm doing it now, but I'm unsure of how I would do that.


I will be traveling from India to Canada via United Kingdom in British Airways flight. The stopover in London is for 6 hours. I will be staying in the airport only. Do I need a transit visa for United Kingdom?

I am traveling from the US to India via London Heathrow on November 6. I will be at LHR on 7th at 6:20 am and departing at 9:25 pm. I'm an Indian national and have a valid US visa.  Do I need a transit visa to stay airside?  I have been scared that British Airways have stopped a few people from boarding flights (no details just rumors).  Do I need a transit visa to stay landside? I want to do some sightseeing. What are the chances of getting past officials using transit without visa concession?  Real stories will help a lot to calm the butterflies in my stomach.


I have bought an Xbox 360 wireless controller and I want to use it on pc, but unfortunately, I cant find the Xbox 360 wireless receiver. Is it possible to use a normal wireless adapter for Xbox 360 controller?

Can I use a wireless XBox 360 controller on a PC?


I wanted to reply to the following thread:   But I am not allowed to. So I am created another here to share my experience.  First, the Behaviour  ~~~~~~~~~~~~~~ When you move over the application icon on the taskbar (that has application opened), you would expect a preview to appear. In this case, although the preview window appears, it will simply auto-disappear (i.e. closed by itself within a very short period of time, e.g. 1s). This behaviour is also evident when you use Alt-Tab.  Very frustrating!  Editing the registry, etc, does not help for me. Setting the aero peek (enable or disable or a mixture of those) also does not help.

OS: Win7 Pro x64 Laptop: Lenovo x240 Dock: Lenovo ThinkPad Basic Dock - Port Replicator  Monitor 1: AOC 21.5", E2243FW (VGA) Monitor 2: Lenovo 21.5", LS2223 (DVI)   Issue:  When hovering the cursor over any pinned/unpinned icon on my taskbar, the preview icon that pops up is quickly fading away (as quickly as it starts up, seemingly with the reverse animation as when it appears).  While holding Alt and pressing Tab to cycle through open applications, the window of icons will disappear (and if I continue to hold Alt and press Tab again, the window will reappear and will start me back at the first icon).  This problem will "randomly" not happen after rebooting and then will begin happening again.  Attempts to resolve:   Fully run the Windows and ThinkVantage System Updates Removed all unnecessary peripherals (keyboard, external CD drive, ect) Changed Visual Effects from "Let Windows choose what's best for my computer" to "Adjust for best performance", as well as Custom (all unchecked, and tried solely checking "Save taskbar thumbnail previews") Used one monitor at a time (tried both monitors separately). Lowered the resolution and refresh rate of each monitor. Removed all external monitors. Used the laptop completely removed from the dock and external peripherals Safemode   Comments:  I have seen some  that can extend  which, as you can imagine, I'm hoping to steer clear of having to make any changes like this. No other Windows 7 machines I've used have had this issue.  My guess is that an application isn't stealing Window's focus since I'm able to leave the Start menu up for an infinite amount of time without it minimizing.  Edit: I notice the amount of time icon previews stay visible varies - they could last 3 seconds, 5 seconds, 10 second, half a second, ect.


I have a dataset from sci-kit learn, fetch_lfw_people.  import matplotlib.pyplot as plt # plotting faces fig, ax = plt.subplots(3,5) # fig.subplots_adjust(wspace=2)  for enumerate_counter, axi in enumerate(ax.flat):     axi.imshow(faces.images[enumerate_counter], cmap='bone')     axi.set(xticks=[], yticks=[],xlabel=faces.target_names[faces.target[enumerate_counter]])   while trying to show images using subplots and labeling each image with proper name, I want to increase the size of each images and also separate them wide enough so that names do not overlap.  I've tried  fig.subplots_adjust(wspace=2)   however this separates images so that names do not overlap however images gets smaller in size.  Anyway I could resolve this issue?

How do you change the size of figure drawn with Matplotlib?


Is it possible to create a table like this one?    The usual structure of tables I use looks like this:  \begin{table}[H]     \begin{adjustbox}{width=\textwidth,center}     % \begin{adjustbox}{center}         \begin{tabular}{lll}             \hline             \multicolumn{1}{l}{\head{XXX}} & \multicolumn{1}{l}{\head{XXX}} & \multicolumn{1}{l}{\head{XXX}} \\             \hline             \ttfamily xxx & \ttfamily xxx & \ttfamily xxx \\             \hline         \end{tabular}     \end{adjustbox}     \vspace{ - 05 mm}     \caption{xxx}     \label{tab:xxx} \end{table}


In addition to  I posted earlier, find below a flag that has been sitting there for 5 months in a row:     Is this acceptable still?

Here is the close queue:        Here is an active flag I have:        I currently have 5 flags pending in the close queue. Some, like this one, are months old. This doesn't feel right and may discourage newer users from flagging things that need attention with the assumption that a flag may be ignored for 4 months, so why bother?  Here are some possibilities:   Bump flags that have been languishing for more than 30 days to the front of the close queue (or weight questions with said flags a bit higher). Won't solve the issue, but will make it less egregious Punishing a misbehaving mod by forcing them to go through every sub-3000 user's flagged close votes in the queue and free them from flag limbo , "a new 10K flag list for "stuck" flags, which would be any close flag that is unhandled within 30 days."   This question has been heavily edited under the assumption that flags didn't get refreshed every day. Apparently they do, thanks to Bill and Asheesh, so sorry about the misdirection. Languishing flags still an issue though!


To get the local fixed IP address, I use:  IP_ADDRESS = socket.gethostbyname(socket.getfqdn())   When I run this command on a DHCP client host, it returns '127.0.1.1'.  I know how to get it by parsing the result of ifconfig, but I would prefer to get it directly from python. Does anyone know how to get it?

How can I find local IP addresses (i.e. 192.168.x.x or 10.0.x.x) in Python platform independently and using only the standard library?


I'm trying to install Maven on my PC, but one of the packages it uses cannot. be installed from the package manager. Specifically libxmlgraphics-commons-java. I try going directly to the archive through my browser but no luck i.e.

Downloading from the main Ubuntu archive is slow even when it's not release day, how can I get apt-get to automatically use a mirror that is close to me?


I'd like to run some of my code when the bpy.ops.object.duplicate() operator is called. Is there a way to attach a callback function to this built-in operator? Or is there a way to create a custom handler?

Blender's application handlers are listed , but is it possible to create a new one?  For example, I'd like an application handler which is a callback for every time I add a strip to the Video Sequence Editor.


I am new to Stack Overflow. Now I am working as an iPhone programmer. I want to develop my skill in  and iOS. How do I get alerts, when new questions are posted with tags related to Objective-C and iOS?

How do I subscribe to the tags that I am interested in?  I like to get notified via email or so, when someone asks new questions or if someone responds to my questions.


Scanner scan = new Scanner(System.in);  System.out.println("Enter a file:");  String fileName = scan.nextLine();  Scanner fileScan = new Scanner(new File(fileName));  int lineCount = 0;  while (fileScan.hasNext() && lineCount <10){     array4[lineCount] = fileScan.nextLine();     lineCount++;   }// printing the file   int max4 = array4[0].length();    for(int i = 1; i <10; i++){       if (array4[i].length() > max4) {   THIS IS WHERE THE PROBLEM IS absolutely lost need assistance          max4=array4[i].length();       }    }    }//end of main  }//end of class having issues with an exception in thread main nullpointer exception

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?


Every time I mount any external hard drive or other partitions and open it in nautilus, clicking on the nautilus icon again opens a new window. Can I stop this from happening? If not, is there any workaround for this because its kinda annoying. Also, there is no way to switch back to the old window apart from doing Alt+Tab.

When I click on "files" in the launcher it opens another window although the normal action is to maximize the window already open. It doesn't always do that. Is it a bug?


Let $G$ be a group. If there exists a positive integer $m$ such that $a^m=1$ for all $a\in G$, then is $G$ finite? That is, all elements should have order that divides the fixed integer $m$. (The set of orders of elements of $G$ is a finite set.)   I have no idea how to prove or disprove this statement. Is there any counterexample for this?

I am in need of examples of infinite groups such that all their respective elements are of finite order.


Is it possible in 14.04 to save the current system settings?   I want (yet again) to install NVidia drives, but I'd like to save the current state of my settings and be able to roll back to the current state in case the drives don't work.

If I want to make a backup of everything I have done since the fresh install of Ubuntu, what are the possible options? What all should I backup? I want to get all the settings that I changed, all the packages I installed, etc.


Egg Russian Roulette:     6 eggs, 5 of which are hard boiled & 1 of which is raw. Players (1v1)   each choose eggs in a turn based system whereby the egg is smashed   against the forehead. The first player to smash the raw egg against   his/her forehead is the loser.   Should you have the option of choosing who goes first, would going first increase or decrease your chances of winning?

Assume that we are playing a game of Russian roulette (6 chambers) and that there is no shuffling after the shot is fired.  I was wondering if you have an advantage in going first?  If so, how big of an advantage?  I was just debating this with friends, and I wouldn't know what probability to use to prove it. I'm thinking binomial distribution or something like that.  If $n=2$, then there's no advantage. Just $50/50$ if the person survives or dies.   If $n=3$, then maybe the other guy has an advantage. The person who goes second should have an advantage.   Or maybe I'm wrong.


I have recently noticed in some companies (technology-based ones in particular) that they end up in a net loss in their annual report (sometimes for the past several years), although their share prices still increase (e.g. Atlassian, Salesforce, etc). Of course, no one can (probably) describe exactly "why" this occurs, but I'm curious to hear your thoughts. Cheers!

I'm struggling to understand the core reason to invest in stocks as a minority shareholder. Majority shareholding makes more sense as you effectively control the company, so you can pay yourself dividends or even sell the entire company at will. You can guarantee your own payback.  However, as a minority shareholder, you don't get to make any of these decisions. You're basically just hoping to eventually, some day get paid, if the majority holders decide so.  Why do so many investors agree to pay now huge sums of money (trillions in total) for something that may eventually pay dividends, and even in the best case, these dividends are only a fraction of the price you paid to acquire these stocks?  The average annual dividend rate for the US stock market is 2%. That means if you bought 100 million worth of shares, you'd have to wait 50 years to recover your investment.  Of course, the most probable way you'd eventually get liquidity for these shares is by selling them to some other starry-eyed investor - which makes the whole thing seem like a giant Ponzi scheme.  Given all that, it's unclear to me why the public is willing to spend so much money to acquire minority shares in companies.


I've only recently been getting involved with PHP/AJAX/jQuery and it seems to me that an important part of these technologies is that of POST and GET.  First, what is the difference between POST and GET? Through experimenting, I know that GET appends the returning variables and their values to the URL string  website.com/directory/index.php?name=YourName&bday=YourBday   but POST doesn't.  So, is this the only difference or are there specific rules or conventions for using one or the other?  Second, I've also seen POST and GET outside of PHP: also in AJAX and jQuery. How do POST and GET differ between these 3? Are they the same idea, same functionality, just utilized differently?

What's the difference when using GET or POST method? Which one is more secure? What are (dis)advantages of each of them?  ()


I had submitted a research proposal to a group during Post Doc application in an university. But I did not join the same university for post doc. Now I got to know that they are conducting the same research I had proposed.   How to deal with this? Though I am not working in the same area now, but it is my future plan.   Is it really good to use other person's proposal?

Last year, I applied to a university which is in Europe so a research statement is a crucial part of the application. I was interviewed by two faculty members and then finally got a rejection letter.    In my research statement, I had a particular idea and described a roadmap for it, though I did not get into technical details. But the idea was there and clearly stated. Recently, I came across a publication where the title is the same as my idea (wording is a little bit different) and is co-authored by one of the members of the interview panel.  The publication has technical details which were not part of my research statement. I believe there is no clear proof here whether my ideas got used or not.    My questions are:   Is this suspicious?   Is this valid and acceptable?


Let's imagine I have a house which makes me profit because I have tenants. Would you buy a part of the house (less than 50%), if I keep all the profit myself and you know I would never sell it? Is't it would be a same that buying a share in a company with no dividend paid? --Edit: Let's reframe the question a bit, what if owning the house and lease out made by as a company. I own the company and then decide to sell the 49% of it. (I keep 51% so can keep the control) I (as a main stakeholder) would decide that I'm the CEO and I would take all the profit as a wage. So no profit, no dividend. What would happen with the share value? Would someone buy it?

I read somewhere that companies are not required to pay dividends to shareholders (this is correct, yes?).   If so, then if company A never pays dividends to its shareholders, then what is the point of owning company A's stock? Surely the right to one vote for company A's Board can't be that valuable.   What is it that I'm missing?


I have a question regarding how to merge lines with same characteristics:  I have this data:     Client | Product  | Date      Hannah |   TV     | 1 Jan      Tom    | Laptop   | 3 Feb      Peter  | iPod     | 2 Jan      Hannah | Laptop   | 5 Feb      Tom    | iPod     | 5 Feb   And I want to create this:     Client | Product-History|      Hanna  | TV-Laptop      |      Tom    | Laptop-iPod    |      Peter  | iPod           |   Anyone know if this is possible in SQL?  If you require actual SQL code to make it easier to respond let me know, it's the first time I ask a question.  Thanks!  Edit: I am using SQL Server

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


import java.io.BufferedReader; import java.io.FileNotFoundException; import java.io.FileReader; import java.io.IOException; // The "FileProcess2" class. /*September 25, 2016  Programmer: Toni L  This is a program to enter in expense values from a specific text file(previously created) and sort them, then add them to get the total. Also calculates the average expense value.*/ public class FileProcess2 {  //Integer to contain number of rows in text file  static int days = 0;  static double hold = 0.00;  //Method to take the double array that contains the expense value and using a bubble sort, organize them from greatest to least then return sorted array   public static Double[] Organiser(Double[] expenses)throws FileNotFoundException, IOException {         for(int i=0 ; i<days ; i++){     for(int y=0 ; y<(days-1) ; y++){      if(expenses[y] < expenses[y+1]){       hold = expenses[y];       expenses[y] = expenses[y+1];       expenses[y+1] = hold;      }     }    }     return expenses;   }  public static void main (String[] args)throws IOException  {      //File Reader to read in the contents of the file   BufferedReader rF = new BufferedReader (new FileReader ("expenses.txt"));   //Actual number of lines in text file is generated   while(rF.readLine() != null){    days ++;   }    //Declaring string array to enter values from text file   Double expenses[] = new Double[days];   while(rF.readLine() != null)   {   }   rF.close();   //Declaring new double array to enter the values from the text file       //Runs Organiser Class   Organiser(expenses);   //Printing values in table format, with column headings.   System.out.println("Number"+"\t"+"Expenses");   for(int s = 0; s<days ; s++){    System.out.println((s+1)+"\t"+ expenses[s]);   }    }    //Calculates the total of the expenses as well as the average/  public static void totaler(double[] expenses)throws FileNotFoundException, IOException {   double hold = 0.00, total= 0.00, average= 0.00;   for(int u = 0; u<days; u++){    hold = expenses[u];    total = hold + total;    average = (total/days);   }   //Outputs the total as well as the average.   System.out.println("The total value of Shelley's purchases is: "+total);   System.out.println("The average value of Shelley's purchases is: "+ average);     } }     When running the program, I cant seem to get it to read in the numbers from the text file properly, because it always gives me a     NullPointerException . I read the documentation for that exception, and I know that it means that my array called expenses[] is null, but I'm not sure how to give it values. Can someone help me?

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


I was trying to create an alias in bash  alias r='!!'   My idea was to create a simple alias r to run the previous command instead of using !! (double exclamation) to run the most recent command as it is hard to type. I know I can alias r='fc -s' to make this work, but I was trying to understand why I am not able to create an alias for !!. I want to understand what !! means to bash and why I'm not able to alias it. I can create alias for other bash builtin commands like alias cdir='cd' but then why not for !! Sorry if I couldn't explain properly.

I have this alias set in my system /etc/bashrc file:  alias root="sudo !!"   The intention of this being to run the last used command using sudo of course. When used, it of course appears to substitute the last command in history to the bashrc file upon shell initialization, and not the actual command that you would get if you were to run sudo !! in an interactive shell. I've also tried alias root="sudo fc -s" to no avail.  I realize this is probably something to do with how the BASH does command substitutions, but can someone explain why this is, and provide a usable substitute?  I'm running BASH version 3.2.51(1)-release (x86_64-apple-darwin13).


Can this be proven? Or does it need a counter example?      For any $a, b, c, d\in\mathbb{N}$, if $a \mid c$ and $b \mid d$ then $ab \mid cd$   Need help.

Determine if this is true or not:  For any natural numbers $a$, $b$, $c$, and $d$, if $a | c$ and $b | d$ then $ab|cd$.  My answer was True, I went:  $a = 2$, $b = 4$, $c = 6$, and $d = 8$. If $2|6$ and $4|8$, then $(2 * 4) | (6 * 8)$.  Is there another way to do it using, for example, a contradiction proof?


When I type any command and after that it asks for password but I can't type that. For example in terminal I type sudo apt-get update and after pressing enter, it asks for password. I type password but nothing appears in the terminal. Whatever i type it don't get typed in case of password. And for each command it asks for password. Any Solution for this?

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?


I have an activity, say A, which has a fragment with a textview called TotalTimerFragment which contains a countdowntimer. There are 2 other fragments called F1 and F2. Activity A adds F1 and the countdowntimer in fragment TotalTimerFragment starts. After a few seconds F1 is replaced by F2. And here the countdowntimer should continue for few more seconds. But it crashes and gives a NullPointerException for the findViewById in the OnTick method in the class.  Here is the code for the FT fragment: getActivity().findViewById(R.id.total_timer_textview) in onTick method gives NullPointerException  public class TotalTimerFragment extends Fragment{     TextView totalWorkoutTimer;     TotalTimeCounter timeCounter;     static long total_millis;      @Nullable     @Override     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {         return inflater.inflate(R.layout.fragment_totaltimer, container, false);     }      @Override     public void onViewCreated(View view, Bundle savedInstanceState) {         super.onViewCreated(view, savedInstanceState);         totalWorkoutTimer = (TextView) getActivity().findViewById(R.id.total_timer_textview);     }      public class TotalTimeCounter extends CountDownTimer {         TextView totalWorkoutTimer;          public TotalTimeCounter(long millisInFuture, long countDownInterval) {             super(millisInFuture, countDownInterval);         }          @Override         public void onTick(long millisUntilFinished) {             total_millis = millisUntilFinished;             String total_hms = String.format("%02d:%02d:%02d", TimeUnit.MILLISECONDS.toHours(total_millis),                     TimeUnit.MILLISECONDS.toMinutes(total_millis) - TimeUnit.HOURS.toMinutes(TimeUnit.                         MILLISECONDS.toHours(total_millis)), TimeUnit.MILLISECONDS.toSeconds(total_millis) -                         TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(total_millis)));             totalWorkoutTimer = (TextView)getActivity().findViewById(R.id.total_timer_textview);             totalWorkoutTimer.setText(total_hms);         }          @Override         public void onFinish() {          }     } }


Do both the following sentences mean the same? If not, what's the difference?  1- Which colleges in India are run by the right wing students' group?  2- What colleges in India are run by the right wing students' group?

Most of the time one or the other feels better, but every so often, "which" vs. "what" trips me up.   So, what's the exact difference and when should you use one or the other?


I'm having a problem with my Netbeans IDE and I'm not sure if I can ask about it on Stack Overflow.   Can I ask question about problems with my IDE on Stack Overflow?

There seems to be more than a few computer science/programming Stack Exchange networks (is that the correct term?). Stack Overflow, being the first, has by far the most users, questions, and answers.  What is the reasoning for creating the others, and are there clear guidelines for which kinds of questions should be posted? I can see a large amount of potential overflow, many cases of people not getting a good answer to their question, because the person who has the answer isn't browsing that particular network at the moment.  I understand that they were probably created for organizational purposes, but wouldn't it almost make more sense to just have them as categories under Stack Overflow, keep them separated but still connected, instead of making people have to create multiple 'account's, one for each network?  I am sure there was a very good reason to break them up, but as someone that is new to SE, it can be somewhat intimidating to decide which one to post in to ensure you get a good answer. For example, if I am a computer science student, my first instinct might to be to post in the computer science network, until I see that it literally has 1% of the users as the Stack Overflow network, which still seems to be for programming/computer science related questions.  So my second instinct would then to be to post it into the Stack Overflow site on the basis that I have a significantly higher chance of my question being seen and getting a good answer. Then I notice that there is also a 'programmers' network, and I don't even begin to know where that fits in. I, and I am assuming most people, will probably just post on Stack Overflow to be safe.  My question is, other than the short little description blurb of each one, is there a clear cut set of guidelines which what each network is intended for, what kinds of questions should go to each one, and is anything being done to encourage people to post in these newer, smaller (more specialized?) networks as opposed to just posting in big daddy Stack Overflow?  Now again, this is for computer science/programming/"why isn't this code doing what I want?" related questions, I am not saying that if I had a question about Linux or WordPress or something I would have the same confusion.


i am very new to Linux as a whole. I use an alienware 15 R2 with Ubuntu 18.04.2 LTS on it.  i have installed matlab R2019a in the folder /media/srikar/Code/Matlab.  The ./matlab code path is /media/srikar/Code/Matlab/bin.  Please help me create a desktop launcher icon. I have gone through other answers for similar cases, but i couldn't figure out how to solve the issue in my case where the installed directory is different from the default. I installed matlab on my external drive.

In older versions it was easy to create a launcher on my desktop. All I had to do is right click on my desktop and select the "create launcher" option.  How can I create such launchers now?


Does anyone know why Starfleet ships are so white? They are research vessels "seeking out new life" but trying NOT to be seen before first contact. Kalemene never would have seen “the Ground-shaker” if it didn’t light up like a star   in Blink of an Eye. Non-reflective paint is all Voyager needed to prevent violating the Prime Directive. Why are their deep space research ships painted like cruise-ships?    Would Voyager still be visible from the ground if it were not white? No, not even an eagle could have seen Voyager at that orbit. They saw reflected sunlight. Here’s the science:  An  - give or take, and every Star Trek planet happens to have earth-like gravity. So even though Kalemane was rotating much faster, this is a safe and stable orbit.  Human eyes can see an object .   the smallest thing you can possibly see at a 36,000 km orbit must be 10,409.75 meters in diameter. Not even an eagle with 20/4 vision could see the tiny 345m long Voyager until it dropped to a 5,900km (3,667 miles) orbit.  So sunlight reflection is the ONLY thing anyone will see from the surface for something as small as Voyager. Even today we have carbon nanotube anti-reflective coatings which would reflect almost zero sunlight, Voyager would have never been spotted by the primitive natives. We also have coatings that reflect RADAR signals. But they came into orbit looking like a shiny Carnival cruise ship.  In the real world naval ships are painted to be difficult to see with the naked eye under the right conditions - commanders understand those conditions and use this in their tactics against smaller low-technologically craft. They will plan to use cover of fog or twilight when it may benefit an operation. Here again radar-absorbing coatings would have prevented the whole temporal incursion disaster in Tomorrow is Yesterday:  (Tomorrow is Yesterday)  So many Prime Directive problems are caused by making their ships white and shiny. It's like sending Dian Fossey out to a new gorillas troop wearing a Ronald McDonald clown costume!    Unlike high-tech cloaking technology, a simple choice of surface coating will let a starship enter a technologically young planet under cover of night without being detected, helping support the Prime Directive in emergencies. Advanced cultures can obviously see the ship with scanners. So what? The Prime Directive doesn't apply to them, we aren't trying to hide from them. Some people think "dark" or "camouflage" looks intimidating. If someone is intimidated, that means somehow they saw you, so either your camouflage isn't working or you used it wrong (coming into low orbit on the daylight side of the planet or something else silly).  To my knowledge every one of these shiny white ships can also land. At least, , so I assume they all do. We saw Voyager land on the Demon Planet. If Voyager had to land on a pre-warp planet for whatever reason - an emergency - with dark colors they could come down on the night side of the planet unseen.  Starfleet is in the business of exploring without being seen. They are supposed to be a distant observer - that's the Prime Directive. But all their ships are painted like showboats. What's the reason for this?

The stealth mode of starships plays a huge role in many Star Trek films and episodes and is a strong advantage in combat. I remember an episode revealing that the Federation developed a secret stealth technology (afair on Riker's former ship with another captain appearing in this episode) that even made it possible to fly with the ship through matter.   Nonetheless, while stealth technology seems standard for Romulans, Klingons (Ferengi, Vulcans?) and does not break any intergalactic laws (do these exist at all?), the Federation doesn't use it?


I have sculpted a model in sculptris (maybe i have done something wrong, it's my first time) and exported it to an object then reduced polygones and stuff, and now i have some stuff to do in blender but i noticed that the center of my model isn't really the center. It has moved to his left and idk how to move it to the right position. I have never used Blender before so maybe it's a dumb question. Here's an image of what it looks like:     I'm not a Blender guru so please be as precise as you can if you know how to fix this.Thank you for your.

So, I'm working creating a lamp... yes, newbie here.  After modeling for a bit, I noticed that my point of origin was no longer the center of my object:    How to I reset an object origin point to the center of it's geometry?


I have imported a model that was generated by Mineways, a software that can convert Minecraft worlds into 3d models. Then I also loaded up the material using the MCPrep addon, but now I have suddenly started noticing some weird black patches on my grass which use transparency (I assume minecraft grass needs transparency). One thing I know for certain is that this problem is getting less bad as I raise the number of transparency light bounces but I have to raise them as high as 10 passes which really cannot be optimal as I want to render an animation with 222 frames on Cycles and it takes forever as I raise max bounces. Is there another way to fix this problem? What is the reason of this in the first place?

Using v2.73, cycles and a very simple scene: an array of cubes, no big deal.   If I set the shader's material to transparent, the cubes in the foreground do become transparent but those far away in the back do not disappear completely and this strange dark things appear (visible in rendered mode and in final renders)    I've played with the clipping distance on the viewport and camera, but I can't figure out how to make those ghosts go away...


A common question I have seen on problems sets and on exam papers is as follows (own words):     Show that $a^\dagger$ and $a$ satisfy the canonical commutation relations. Hence show write down the eigenvalues and eigenvectors of $a^\dagger a$.    The expected answer is as follows :     The eigenvalues are $n=0,1,\ldots$ and the eigenvectors are - spare a normalization: $$(a^\dagger)^n \left|0\right>$$   where $a \left|0\right>=0$.   It is clear from the commutation relations that if we have an eigenvalue $\lambda$ then we have a string of eigenvalues: $$\ldots, \lambda -2,\lambda -1, \lambda, \lambda+1,\lambda+2,\ldots$$ if $\lambda$ is a natural number then this string is bounded by below by $0$ and it is always bounded above by $\infty$. The expected answer I have given above has made two (in my opinion, fairly large) assumptions:   There is only one string present. I.e. there is no eigenvalue $\lambda_2$ such that $\lambda_2 \ne \lambda+k$ for some $k \in \Bbb{Z}$. The string that is present has $\lambda \in \Bbb{N}$.   These assumptions hold for the case of the Harmonic oscillator - this can be shown by explicitly solving the Hamiltonian. But often there are no harmonic oscillators in sight - for example in the Fock space representation$^\star$.   Thus my question is: under what circumstances do we expect the above assumptions to be valid and why?   $\star$ Only an example - not the focus of my question.

The standard treatment of the one-dimensional  (SHO) using the raising and lowering operators arrives at the countable basis of eigenstates $\{\vert n \rangle\}_{n = 0}^{\infty}$ each with corresponding eigenvalue $E_n = \omega \left(n + \frac{1}{2}\right)$. Refer to this construction as the abstract solution.  How does the abstract solution also prove uniqueness? Why is there only one unique sequence of countable eigenstates? In particular, can one prove the state $\vert 0\rangle$ is the unique ground state without resorting to coordinate representation? (It would then follow that the set $\{\vert n \rangle\}_{n = 0}^{\infty}$ is also unique.)  The uniqueness condition is obvious if one solves the problem in coordinate representation since then one works in the realm of differential equations where uniqueness theorems abound. Most textbooks ignore this detail (especially since they often solve the problem both in coordinate representation and abstractly), however I have found two exceptions:   Shankar appeals to a theorem which proves one-dimensional systems are non-degenerate, however this is unsatisfactory for two reasons:   Not every one-dimensional system is non-degenerate, however a general result can be proven for a large class of potentials (the SHO potential is in such a class). The proof requires a departure from the abstract solution since it classifies the potentials according to their functional properties.  Griffiths addresses this concern in a footnote stating that the equation $a \vert 0\rangle = 0$ uniquely determines the state $\vert 0\rangle$. Perhaps this follows from the abstract solution, however I do not see how.


I was trying to smoothen my character by pressing Ctrl + 5 ; it made it smoother but I ended up with a line and a crease in my character.

I've followed the same  I mentioned in the question I asked  and my boat hull looks pretty good.  The process is to make 3D B-Splines increase the resolution and then convert them to Mesh Elements.  Then you make a plane and cut it in half along the "Y" axis.    I followed through the process and see a couple issues that I would like one of you to address.  First, I see that the normals are not correct.  The inside of the hull is not important but the outside needs to show materials.  Also the hull is not stitched together along the keel.  I don't know how to do that on a mesh that has had the Mirror Modifier applied to it.    Anyone care to help?


The general definition of a differentiable mapping is,  Let U be an open set in Rn, and let ‘a’ be in U and f:Rp. Then f is a differentiable mapping at ‘a’ if there exists a Df(a) in Hom(Rn, Rp) such that;  lim┬(x→a)〖(||f(x)-f(a)-Df(a)(x-a) ||)/(||x-a||)〗=0  Why is U necessarily an open set?

I was looking up the definition of the derivative in several books, and what was making me uneasy was the first sentence, generally along the lines of "let $f$ be defined on...". They don't seem to be able to agree on what $f$ should be defined on. Most books say "interval"; one says "open set"; another just says "let $f$ be a real-valued function"; etc. So I decided to do a little investigation.  At the end of the day, we always define the derivative as the limit of a difference quotient (two versions), so we need to look into limits of functions. It turns out that the limit of $f$ at $a$ is only defined for $a \in (\operatorname{dom} f)'$ (we'll denote the set of cluster points of $A$ by $A'$ for convenience), because otherwise, the $0 < |x - a| < \delta$ part of the definition can be made false by choosing $\delta$ small enough to isolate $a$, thereby making the implication vacuously true, which gives non-unique limits, but we don't want that. So at this point, we know that $a$ must be a cluster point of the domain of the difference quotient.  A slight digression: It's easy to show that if $B$ is a finite set, then $A' = (A \cup B)' = (A \setminus B)'$. (That is, "adding" or "subtracting" a finite number of points doesn't affect the "stickiness" of a set.)  Let $A \subseteq \mathbb R$ and let $f: A \to \mathbb R$. For each $a \in A$, we can define a difference quotient function $q_a: A \setminus \{a\} \to \mathbb R$ by $$q_a(x) = \frac{f(x) - f(a)}{x - a}.$$  Now, (in a rather perverted pseudo-self-referential manner), we can define $$f': \{a \in A \cap A': \lim_{x \to a} q_a(x) \in \mathbb R \} \to \mathbb R \qquad \text{by} \qquad f'(a) = \lim_{x \to a} q_a(x).$$  We need $a \in A$ because $f(a)$ is needed to evaluate $q_a$, and we need $a \in A' = (A \setminus \{a\})' = (\operatorname{dom} q_a)'$ for the limit to be defined. So really, derivatives can be defined on sets that are much more general than intervals: we really only need $\operatorname{dom} f \cap (\operatorname{dom} f)' \neq \varnothing$ in order to talk about the derivative of $f$ at some point (of course, the derivative itself need not exist, but at least we can talk about it not existing).  And then I started getting worried... The function $f: \mathbb R \to \mathbb R$, defined by $$f(x) = \begin{cases} x, & x \in \mathbb Q, \\ 0, & x \notin \mathbb Q, \end{cases}$$ has no derivative anywhere. But if we restrict the domain to $\mathbb Q$, then suddenly every point is differentiable with derivative $1$? Now I'm starting to wonder if I made some stupid mistake in the development above, but I can't seem to find it.  So the question is, is the bolded statement above true?


Let $A$, $B$ be sets and denote by $A\leq^* B$ an assertion that if $A$ is non-empty, then there's a surjection from $B$ onto $A$. This might be understood as a dual definition of cardinality. (Typically we use injections to capture the notion of A not being bigger than B. The $\leq^*$ notation is to be read as B not being smaller than A.)  Is this relation trichotomous without using the axiom of choice? Meaning for every two sets $A$ and $B$, it holds $A\leq^* B$ or $B\leq^* A$. (I would be surprised). Would trichotomy imply some interesting extra-ZF axiom?  More broadly, is there anything to be said about $\leq^*$? For example how does it relate to the usual comparisons of cardinality by injections?  I suspect there's no clear answer, since it is somehow reminiscent of Partition Principle ($A\leq^* B \implies A\leq B$) and Weak Partition Principle ($A\leq^* B \implies B\not< A $) which both are independent of ZF.

In ZFC, a good way of ordering sets by cardinality is by leveraging the notion of an injection. We define: $$X \lesssim Y \leftrightarrow \mbox{ there exists an injection } X \rightarrow Y.$$  Alternatively, we can leverage the notion of a partial surjection, by which I mean a partial function that hits every point of its codomain at least once.  $$Y \succsim X \leftrightarrow \mbox{ there exists a partial surjection } Y \rightarrow X.$$  Now in ZFC, these approaches are equivalent, in the sense that $$X \lesssim Y \iff Y \succsim X.$$  But if we just consider ZF (that is, we drop choice) then the equivalence breaks down. However, we've still got the forward implication, because the converse of an injection is always a partial surjection.  A specific question. Define that two sets are weakly equipotent iff $X \succsim Y$ and $Y \succsim X$. Question: does weak equipotence imply genuine equipotence? I'm guessing "no."  A general question: In broad terms, how would the structure of the cardinal numbers in ZF be altered by adopting $\succsim$ rather than $\lesssim$ as the fundamental order relation, and taking equality of cardinal numbers to correspond to weak equipotence of sets? I'm guessing this would hide a lot of the (usually very complicated) structure of the cardinal numbers in ZF.  Remark. The order symbols can be written \lesssim and \succsim.


So I got some overpowered weapons from a friend and decided to start destroying bosses...killing Skeletron, the eye of cthulu and his brains, plus the eater or worlds and skeleton prime, and the wall of flesh...but then I hit a roadblock. I need help killing the twins...any advice?  Note: if it is important, I have hallowed armor, every NPC housed and I play Xbox 1/console

In Terraria I often try to defeat spazmatism first, but when he transformed, his flamethrower killed me. What is easiest way to kill The Twins?


I want to have a part of my render be a very specific color, for the whole object. Is there a way to do this?

I wan't to create a segmentation map for machine learning. For that I have a list of colors like:  clouds  #aaaaaa cow     #4f445b grass   #1dc331   It is from absolute importance that the render has the exact same colors.  I tried:   And:   But in the render the colors are off. How can I get a render with the exact colors I give?


If we do the wick rotation such that τ = it, then Schrödinger equation, say of a free particle, does have the same form of heat equation. However, it is clear that it admits the wave solution so it is sensible to call it a wave equation.   Whether we should treat it as a wave equation or a heat equation with imaginary time, or both? If it is a wave equation, how do we express it in the form of a wave equation? Is there any physical significance that Schrödinger equation has the same form of a heat equation with imaginary time? For example, what is diffusing?

Wave equations take the form:  $$\frac{ \partial^2 f}  {\partial t^2} = c^2 \nabla ^2f$$  But the Schroedinger equation takes the form:  $$i \hbar \frac{ \partial f}  {\partial t} = - \frac{\hbar ^2}{2m}\nabla ^2f + U(x) f$$  The partials with respect to time are not the same order. How can Schroedinger's equation be regarded as a wave equation?  And why are interference patterns (e.g in the double-slit experiment) so similar for water waves and quantum wavefunctions?


User input a number such as 1234569775 of 10 digit. may on of the digit has a Value of X and this mean its equal to number 10  SO i write my code       Scanner in=new Scanner(System.in);     String a=in.next();     String arr[]=new String[10];     for (int i=0;i<arr.length;i++)     {         arr[i]=String.valueOf(a.charAt(i));     }     for (int i=0;i<arr.length;i++)     {         if (arr[i]=="X")         {             arr[i]="10";         }     }     System.out.println(Arrays.deepToString(arr)); }   but its the value of X does not change and I try to make a new array and does not make any change too last thing i want to change this String array all value in it to Integer so I can make any Mathematical operation on them So I want   Change value of X to 10 Change the array values to Integer   How can I do that in Java?

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'm trying to set the width and the height for a Python GUI Application with tkinter. But it gets ignored, it also doesn't show any warnings or error messages.  I'm passing the root window in as master to my class. However when I set the width and height of the frame. It doesn't change the size of the screen. I'm experimenting with Python(C#, iOS background) and I can't figure out what i'm doing wrong. I saw a tutorial that did exactly the same as me, and he was able to set the height and width of the application with exactly the same code that I included below.       from tkinter import *      class MainWindow:     def __init__(self, master):         frame = Frame(master, width=300,height =250)         frame.pack()         button1 = Button(frame, text="Click on me", command=self.btnLoginClicked)         button1.pack(side=LEFT)      def btnLoginClicked(self):         Download.downloadFileFromUrl()  root = Tk() w = MainWindow(root) oot.mainloop()   Is this the right way to set the size of the window? Did I forget something or do I need to set it somewhere else?  EDIT: Below code does the job perfectly. So there might be a problem in my class  root = Tk() frame = Frame(root, width=1000, height=700) frame.pack()  root.mainloop()

This is the code that's giving me trouble.   f = Frame(root, width=1000, bg="blue") f.pack(fill=X, expand=True)  l = Label(f, text="hi", width=10, bg="red", fg="white") l.pack()   If I comment out the lines with the Label, the Frame displays with the right width.  However, adding the Label seems to shrink the Frame down to the Label's size.  Is there a way to prevent that from happening?


I have an excel spreadsheet with co-ordinates (eg. S31 07 35.3). I would like to use these co-ordinates in arcmap (version 10.2) to plot points based on these coordinates. How do I go about doing this because I cannot use the co-ordinates as is? So basically, I need a way of converting these co-ordinates into something arcmap will understand.

I need to convert lat/long that is expressed as degrees, minutes, and seconds in the data into decimal degrees. For example, in the data, they are listed as N335042.06 in the Latitude column, and W86031.04 in the Longitude column. I have done this problem before where I created a script which converted DMS to DD, and vice-versa, so I guess I could use bits from that. But the problem I'm having is how to ignore (for lack of a better word) the 'N' and 'W' in the data? Can I skip them? And DMS are listed all together without any symbols or spaces.  Can I use len(), range(), split() to specify what part to read from the value? For example, can do the following?  N335042.06 where, 33 = degrees 50 = minutes 42.06 = seconds ...?  I came across  ESRI article, but it's in VB. Will probably use it as a reference but some of the terminology/syntax is different from Python.  Final code that works!   # Pre-logic def latDD(x):   D = int(x[1:3])   M = int(x[3:5])   S = float(x[5:])   DD = D + float(M)/60 + float(S)/3600   return DD  # Expression latDD(!Latitude!)


Like every object applies gravitational force to every other object. The reason can be in the General Theory of Relativity. In the same way why magnetic field applies force on moving  charge (and why only on charge)?

Lorentz force is in this form: $$\vec{F}=q[\vec{E}+\vec{u}\times\vec{B}]$$ As we know, it is Lorentz-invariant. Is there any way to justify or derive its form from relativity theory?


When I use cleveref-based cross-references to, say, sections in another chapter, these references just print Section n. It's then difficult to distinguish references to a section of another chapter from references to a section of the present chapter. I'm using the amsbook documentclass, as @Mico points out is important to mention.   I presume there's a good pre-built solution to this issue---what is the existing pre-built, pre-packaged solution? Again, this is I assume a well-trod issue, so I'd love to know the generally accepted solution rather than rolling my own.  I'd certainly rather avoid having to manually write \cref{sec:section} of \cref{chap:chapter} in the relevant places.   I'd also rather avoid having to change the style to display as Section n.m everywhere, or further as Subsection n.m.k. Most of the time these references are within the same chapter or section, so it'd be nice to show only external structure when relevant.   I'd be fine with generating Section m of Chapter n automatically, or switching to the notation of Section n.m, when relevant.   I'm currently using varioref as a workaround, and I also use hyperref in my document.    The following seem strongly related:

Consider the following piece of code:  \documentclass{book} \usepackage{cleveref} \usepackage{lipsum}  \begin{document}   \chapter{Chapter One}   \section{Section One.One}   \label{mysection}   \lipsum    \section{Section One.Two}   Please ignore \cref{mysection}.    \chapter{Chapter Two}   \section{Section Two.One}    As you may have noticed, \cref{mysection} is useless. \end{document}   By default, in both uses of \cref I get Section 1.1 as expected.   Is it possible to change the way the reference is shown in such a way that the second use of \cref above will print Section 1 of Chapter 1? i.e., naming the parent counter as well.   However, this should be done only outside the own chapter, so the first use of \cref in the above example should print Section 1.  This comes from a use case of a normative text where the document is divided in "articles" and "commas", and it is good to have references like "Comma 1 of Article 2" or "Article 2, Comma 1".


There is a related question  but two highly upvoted answers there don't seem to agree with each other, and in any case I wanted to take a different tack.  Is AIC useful for comparing:   non-nested models only. nested models only. either non-nested or nested models.   Why/Why not?

Say we have to GLMMs  mod1 <- glmer(y ~ x + A + (1|g), data = dat) mod2 <- glmer(y ~ x + B + (1|g), data = dat)   These models are not nested in the usual sense of:  a <- glmer(y ~ x + A + (1|g),     data = dat) b <- glmer(y ~ x + A + B + (1|g), data = dat)   so we can't do anova(mod1, mod2) as we would with anova(a ,b).  Can we use AIC to say which is the best model instead?


How do I save a random string from a list so I can recall the exact thing later in the code? For example:  name = ['Hans', 'Peter', 'Eliza'] print('Your name is ' + random(name) + '!') print(name)   What can I use here in place of random(name), and how can I save it?

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


Sorry if this is a stupid question, but I'm very new to java.  Basically we are learning about interfaces and maps right now in my java class.  I created an interface that is really simple, and have also created other classes that implement that interface.  In my class that is a main actor, I am creating a map and I've created instances of these as you can see below.  I'm getting a NPE and I am not sure why.    private Scanner input; private Map<String, Command> map;  //~ Constructors .......................................................... // ---------------------------------------------------------- /**  * Creates a new Rocket object that reads commands  * from a predefined URL (the URL is in the lab assignment).  */ public Rocket() {     this(IOHelper.createScannerForURL(             "http://courses.cs.vt.edu/~cs1114/Fall2012/rocket-commands.txt")             );  }  // ---------------------------------------------------------- /**  * Creates a new Rocket object that reads commands  * from the given scanner.  * @param scanner The scanner to read commands from.  */ public Rocket(Scanner scanner) {     input = scanner;     map = new HashMap<String, Command>();     ForwardCommand forward = new ForwardCommand(this);     map.put("forward", forward);     LeftCommand left = new LeftCommand(this);     map.put("left", left);     RightCommand right = new RightCommand(this);     map.put("right", right); }  //~ Methods ............................................................... // ---------------------------------------------------------- /**  * Reads one word from the scanner (if there is any), and executes  * the corresponding command.  If the scanner has no words remaining,  * then nothing happens.  */ public void act() {     if (input.hasNext())     {         String word = input.next();          map.get(word).execute();     } }   }  The error is coming on the line map.get(word).execute();  I'm sure it is something obvious, but I am very new to coding so any help would be appreciated!

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?


The title says pretty much everything:     We have $z\in\mathbb{C}$ such that $\|z\|=1$ and a monic polynomial $p\in\mathbb{Z}[x]$ such that $p(z)=0$.   Is it true that for some $n\in\mathbb{N}$, $z^n=1$?   My thoughts about it: assume that $z=e^{\pi i\alpha}$ and $z$ is not a root of unity, i.e. $\alpha\not\in\mathbb{Q}$. Then $\alpha$ has to be a trascendental number: otherwise, by the , $z$ is a trascendental number. But obviously this is far from closing the question: for instance, $\frac{3+4i}{5}$ is a complex number with unit modulus, and $\frac{1}{\pi}\arctan\left(\frac{4}{3}\right)$ is a trascendental number, but there is no monic polynomial with integer coefficients having $\frac{3+4i}{5}$ as a root. So, what is the good way to go for proving the claim above, since I believe it is true? Counter-examples are welcome as well, obviously.

If we have an algebraic number $\alpha$ with (complex) absolute value $1$, it does not follow that $\alpha$ is a root of unity (i.e., that $\alpha^n = 1$ for some $n$).  For example, $(3/5 + 4/5 i)$ is not a root of unity.  But if we assume that $\alpha$ is an algebraic integer with absolute value $1$, does it follow that $\alpha$ is a root of unity?    I know that if all conjugates of $\alpha$ have absolute value $1$, then $\alpha$ is a root of unity by the argument below:  The minimal polynomial of $\alpha$ over $\mathbb{Z}$ is $\prod_{i=1}^d (x-\alpha_i)$, where the $\alpha_i$ are just the conjugates of $\alpha$.  Then $\prod_{i=1}^d (x-\alpha_i^n)$ is a polynomial over $\mathbb{Z}$ with $\alpha^n$ as a root.  It also has degree $d$, and all roots have absolute value $1$.  But there can only be finitely many such polynomials (since the coefficients are integers with bounded size), so we get that $\alpha^n=\sigma(\alpha)$ for some Galois conjugation $\sigma$. If $\sigma^m(\alpha) = \alpha$, then $\alpha^{n^m} = \alpha$.  Thus $\alpha^{n^m - 1} = 1$.


I'm considering disabling the next and done buttons on my wizard until all of the required fields on the corresponding step have been completed.  My first thought is that if something shouldn't be clicked then disable it until it can be. However, I'm realising there may be an issue with doing that in this scenario, the main one being that the user may not know what to do in order to get the next button enabled.  What is best practice in this scenario?

How do you think about disabling the submit-button until the user has completed the form or the required fields?   I find similar questions here on ux.se and somebody answered that the user will think that the form is broken or not immediately realize whats going on.  I think hiding is not that good but a disabling (e.g. grayscale, opacity, ...) plus a short text in the button would improve usability because the user realise that he still has to fill out something.  Is there anybody with experience or examples besides the usual error-messages/validation after submitting?


Can I write this sentence:     He said Carter had better not entangle the US in problems like those   in Afghanistan, Somalia and Iraq.   Like this:     He said Carter had better to not entangle the US in problems like those   in Afghanistan, Somalia and Iraq.   ?  If so, what's the difference between the meaning of both sentence?

[i] He hadn’t better tell them. (CGEL, p.113)   [ii] He had better not tell her. (CGEL, p.196)   According to CGEL, negation can be marked after or before better. But I can’t find any examples of [i] in COCA or BNC. So it seems to be not grammatical issue but others in there. Why aren’t there any examples of [i] in those corpuses?


I read  article about the working of Full Joins. The article says that a Full Join, which combines the results of Left Join and Right Join, "retains duplicate rows". Therefore, in order to simulate a FULL JOIN, we use UNION ALL instead of UNION. But, when I perform a FULL JOIN on two tables in Oracle, I do not find duplicates at all. (I believe, Oracle internally uses the 'UNION ALL' operation on left and right joins to perform a FULL JOIN.) The left join and right join contain some common rows, but when I run a full join, those common rows don't appear twice. Results of Left Join : SELECT * FROM ORDERS LEFT JOIN CUSTOMER ON ORDERS.CUSTOMERID = CUSTOMER.CUSTOMER_ID;  Results of Right Join : SELECT * FROM ORDERS RIGHT JOIN CUSTOMER ON ORDERS.CUSTOMERID = CUSTOMER.CUSTOMER_ID;  Results of Full Join : SELECT * FROM CUSTOMER FULL OUTER JOIN ORDERS ON CUSTOMER.CUSTOMER_ID = ORDERS.CUSTOMERID;  As you can see from the results of FULL JOIN, it "Does not contain duplicate rows" , even though left join and right join have some common rows. So, why is it believed that a full join contains duplicate rows ? Am I missing something ?

Also how do LEFT JOIN, RIGHT JOIN and FULL JOIN fit in?


Simply, can I pass std::vector as a template argument. Following example list usage  tempate<typename container_t, typename value_t> struct container_types {   typedef container_t<value_t> value_container_t;   typedef container_t<pair<value_t> pair_container_t;  };   I wish to pass container_types to generate final two data types.  If this is not feasible, then how can I achieve the same.

I've seen some examples of C++ using template template parameters (that is templates which take templates as parameters) to do policy-based class design. What other uses does this technique have?


After what seems a human-directed ransomware attack, I am analyzing the system. It is a Windows Server 2016 and I had created the usual Administrator account. Now I see that during the attack, a new "Administrador.WIN-RSDLE3HIAER" account has appeared under C:\Users folder. The old plain Administrator still exists but it seems like all files are now under the newly created account (Donwloads, favorites, Desktop, etc... are still in the original account, but empty). It is like the profile was moved to the new Account.   My question, in the search of learning is why is this done, why creating a new account? Is this some kind of self-protection from the attackers? Why is all my original content now under the newly created account? I could still enter "Administrator" under the login page and access my profile so this is why I cannot understand the nature of the new account/folder, how I got redirected... in a word... how does this thing work?  Cheers

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


The  shows dynamically the reviewers in a horizontal list that change for every review. This is looking really cool. But does it contain useful information? Not really. On the left side we see the numbers of remaining reviews. This is static. Does it contain useful information. Yes! I.e. it would prevent me from opening a queue that is already empty. Please make the numbers dynamic too!! * * This would also look really cool BTW.

With reference to the question , when reviewing in SO, we have to refresh the page every now and then to view the newly added entries to the review queue.  However, votes and reputation are updated on the display as soon as a vote is cast, and as soon as reputation changes. Is it possible to integrate this kind of feature to see the number of pending entries in the review queues page.  This request is probably not a duplicate of , where the feature is requested for a counter in front of the title of the page. But, my question adresses the .


Let $v$ denote a nonzero vector in $\Bbb R^n$  Show that $P = \{x \in \Bbb R^n  \mid  x \cdot v = 0\}$ is a subspace of $\Bbb R^n$. Show that $\Bbb Rv = \{t \cdot v  \mid   t \in \Bbb R\}$ is a subspace of $\Bbb R^n$  I looked through my textbook but couldn't find an example similar to this. How would i solve this?

Show  $S=\{ x \in \mathbb R^n\mid x\cdot v=0 \}$ is a subspace of $\mathbb R^n$. Show $\mathbb Rv=\{tv\mid t \in \mathbb R\}$ is a subspace of $\mathbb R^n$ and describe $S$ and $\mathbb Rv$ geometrically when $n=3$.   I know I should check property of subspace, but in these two cases I have no idea how to start. Someone give me a hint?


My office has multiple Windows 8 Machines and slow internet. Is there a place online I can download the 8.1 upgrade from home on my fast internet so I can do a network or usb install at the office? I don't want to have to download 3GB+ of updates on each and every machine through the Windows store over our slow internet connection.  The Windows 8 PC's in question are OEM Windows 8 Home, upgraded to Windows 8 Pro via the online Pro pack upgrade.

Windows 8.1 is out, and I would like to know if it is possible to share the Windows 8.1 download upgrade between different computers so that I don't have to download it over and over again?  This might be helpful for people who are on a metered connection. Store is downloading 3.42 GB of data so it must be stored somewhere. Is there a way I can copy it to my other computers and start the setup so that I don't have to download it over and over again on each computer I own?


So I have a video and I have the checker texture, and have set it up so that its black and white, and then I put the color into alpha of the output node, so that I have this white and transparent dotted line. BUT, the "transparent" part of the line goes THROUGH an object right behind it.  I'm using blender internal. help?

The images have alpha channel checked on. In normal view the image looks fine but when I render the images cutoff the ones behind it.    There should be no gap between those 2 images but the one closer to the camera is cutting off the one behind it. I used the import images as planes addon. My goal is to export a png file that is transparent except for the colored areas. I'm gonna import this file into Unity so it needs to have a transparent background.


Polyjuice Potion recognizes the victim (whose identity is compromised) by using his/her hair or something.  In case of Love Potion, victims actually eat or drink the Love Potion, but how does Love Potion know who the attacker (with whom the victim get infatuated) is?  When Love Potion is brewed, it certainly is neutral without attacker identity. That's why, so many of girls were able to order the Love Potion from Weasleys' Wizard Wheezes. What do girls do to the Love Potion after getting it and before sending it to target boy?

When someone drinks a "love" potion then he/she becomes obsessed with someone for a short time. But how is this someone choosen?  It is not (always) the one who crafted the potion because Fred and George were selling it.


I am designing a guitar pedal using OpAmps, and i need to feed them with +6V and -6V (beucase the musical signal is senoidal centered in 0V). I need to use a 12V DC PSU for the pedal, and i need to convert to positive and negative voltage. If possible it would be better if it was +12V and -12V but if its not possible i can work with +-6V. I also need this to be reasonably simple and cheap. Thanks!

I'm working on a 9V VCO (synthesiser) that has three op amps, of which two needs virtual ground. So far I've been using voltage divider with a couple of caps and it works. I wonder if I need a separate power supply for each op amp? Is the TLE2426 any better? Do I need two of the TLE2426 for the two op amps?


This January my family and I are returning to the UK from a holiday in Australia. The ticket is booked from Canberra to LHR via Sydney and Doha with Qatar, flight 907 I believe.  Because we're finishing our holiday in Sydney (we start in Canberra), we were hoping to simply join the flight in Sydney, and avoid a 3 hour drive to Canberra, followed by an extra leg back to Sydney.  We contacted the travel agent (Expedia) to confirm if this was possible, and they said the Sydney stop is refuelling only, and we can't board there. Is that really the case? Would it be worth contacting the airline directly to confirm one way or the other?

I'm looking to book flights from) Philadelphia (PHL) to Detroit (DTW). Direct flights are quite expensive. I noticed, in expanding a search to surrounding airports, that I can book from Allentown (ABE) to Detroit for far less, and the connection is through Philadelphia.  Can I book this flight but board in Philadelphia? I'll be traveling with carry-on luggage only, so on the return, it's obviously no problem. But would I be allowed through security and on to the plane in PHL with out having flown from Allentown?


I bought a new DELL Inspiron 15 and installed Ubuntu 16 and having trouble staying connected to the internet.  I'm using my iPhone's hotspot via USB to access internet. But the connection keeps dropping every 1-5 minutes. I have to unplug the USB cable and reconnect to get internet access again. Using this method seems to randomly freeze the whole system as well.  Using Bluetooth to connect to my phone results in a stable connection and the computer does not freeze anymore. But this method is quite slow.  I also went to a coffee shop for wifi, which seems to work so far.  What i tried so far is editing the wired connection for the phone in network settings an set IPv6 to ignore.  I also ran sudo apt-get update & sudo apt-get dist-upgrade with no success.  lspci | grep -i net shows me this as my network adapter:  01:00.0 Network controller: Qualcomm Atheros QCA9565 / AR9565 Wireless Network Adapter (rev 01)

Just installed Ubuntu 18.04 but my WiFi adapter Qualcomm Atheros QCA9565 / AR9565 Wireless Network Adapter doesn't work or even appear in the system settings.  output of lspci -knn | grep Net -A3:  > rahul@rahul-Inspiron-3542:~$ lspci -knn | grep Net -A3 06:00.0 Network controller [0280]: Qualcomm Atheros QCA9565 / AR9565 Wireless Network Adapter [168c:0036] (rev 01)     Subsystem: Dell QCA9565 / AR9565 Wireless Network Adapter [1028:020c]     Kernel driver in use: ath9k     Kernel modules: ath9k 07:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8101/2/6E PCI Express Fast/Gigabit Ethernet controller [10ec:8136] (rev 07)   output of lspci -knn | grep Net -A2  rahul@rahul-Inspiron-3542:~$ lspci -knn | grep Net -A2 06:00.0 Network controller [0280]: Qualcomm Atheros QCA9565 / AR9565 Wireless Network Adapter [168c:0036] (rev 01)     Subsystem: Dell QCA9565 / AR9565 Wireless Network Adapter [1028:020c]     Kernel driver in use: ath9k     Kernel modules: ath9k   output of sudo rfkill list  rahul@rahul-Inspiron-3542:~$ sudo rfkill list [sudo] password for rahul:  0: dell-rbtn: Wireless LAN     Soft blocked: yes     Hard blocked: yes 1: phy0: Wireless LAN     Soft blocked: no     Hard blocked: no 2: hci0: Bluetooth     Soft blocked: yes     Hard blocked: no   output of sudo lshw -C network  rahul@rahul-Inspiron-3542:~$ sudo lshw -C network   *-network DISABLED                description: Wireless interface        product: QCA9565 / AR9565 Wireless Network Adapter        vendor: Qualcomm Atheros        physical id: 0        bus info: pci@0000:06:00.0        logical name: wlp6s0        version: 01        serial: 4c:bb:58:30:aa:07        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress bus_master cap_list rom ethernet physical wireless        configuration: broadcast=yes driver=ath9k driverversion=4.17.11-041711-generic firmware=N/A latency=0 link=no multicast=yes wireless=IEEE 802.11        resources: irq:18 memory:f7900000-f797ffff memory:f7980000-f798ffff   *-network        description: Ethernet interface        product: RTL8101/2/6E PCI Express Fast/Gigabit Ethernet controller        vendor: Realtek Semiconductor Co., Ltd.        physical id: 0        bus info: pci@0000:07:00.0        logical name: enp7s0        version: 07        serial: 74:e6:e2:14:2a:c8        size: 10Mbit/s        capacity: 100Mbit/s        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation        configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=half firmware=rtl8106e-1_0.0.1 06/29/12 latency=0 link=no multicast=yes port=MII speed=10Mbit/s        resources: irq:19 ioport:e000(size=256) memory:f7800000-f7800fff memory:f2100000-f2103fff   *-network        description: Ethernet interface        physical id: 2        logical name: enp0s20u1        serial: 7a:14:5b:44:b4:96        capabilities: ethernet physical        configuration: broadcast=yes driver=rndis_host driverversion=22-Aug-2005 firmware=RNDIS device ip=192.168.42.109 link=yes multicast=yes   output of dmesg | grep ath9k  rahul@rahul-Inspiron-3542:~$ dmesg | grep ath9k [   23.712505] ath9k 0000:06:00.0 wlp6s0: renamed from wlan0   output of sudo iw dev  rahul@rahul-Inspiron-3542:~$ sudo iw dev [sudo] password for rahul:  phy#0     Interface wlp6s0         ifindex 3         wdev 0x1         addr 4c:bb:58:30:aa:07         type managed         txpower 0.00 dBm   output of dmesg   I already tried so many solutions but nothing works for me , I'm looking for answer from so many days. Please Someone solve my issue . If anyone want any other information please let me know.  Any help would be greatly appreciated.


The STL file contains three models separated by amble space in a group meaning can't move one model without the others moving also. I like to ungroup the models into separate model to add more 3D mesh .... can this be done? Thanks

I've just made a set of armor by using a male body mesh model I downloaded and selecting certain faces from the model and duplicating them to create viable armor pieces.   Since the pieces are just duplicated from the same mesh male model, then it's still part of the same object.   How do I separate the armor piece from the model to make the pieces separate?


I tried to do an update to my system (12.04 LTA 64bit, on ACER aspire V5) got this:     Could not initialize the package information      An unresolvable problem occurred while initializing the package information.      Please report this bug against the 'update-manager' package and include the following error message:  E:Encountered a section with no Package: header, E:Problem with MergeList /var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_precise-security_main_binary-i386_Packages, E:The package lists or status file could not be parsed or opened.    Now What?

The computer gave me this output in a window:  E: Encountered a section with no Package: header E: Problem with MergeList /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_natty_main_binary-i386_Packages E: The package lists or status file could not be parsed or opened.   How can I fix this?


I know it's not supported natively for some reason, but I'd really like to lay back on my couch and enjoy the game in a relaxed position instead of sitting straight up at the table with more keys than I need under one of my hands.  Is there a way to play Diablo 3 with a gamepad?  I'm interested in solutions for any kind of PC-compatible gamepads, so please specify which ones your solution supports.

Can I use a game controller with Diablo 3? Since there are not that many keys that are actually used, can you map a controller to play? Or would this require some type of mod?


I found two very useful posts about the difference between linear regression analysis and ANOVA and how to visualise them:      As stated in the first post, to test whether the average height of male and females is the same you can use a regression model ($y = \alpha + \beta x + \epsilon$, where $y$ denotes height and $x$ denotes gender) and test whether $\beta = 0$. If $\beta = 0$, then there is no difference in the height between males and females. However, I am not quite sure how this is tested when you have three groups. Imagine the following example:  height (y) -  group (x) 5          -  A 6          -  A 7          -  A 6          -  A 30         -  B 32         -  B 34         -  B 33         -  B  20         -  C 19         -  C 21         -  C 22         -  C   The regression model would look like:  $$y = a+ b x + \epsilon$$  I quickly visualized the data (see image below)  They way I understood the regression model is that it would now test whether any of the three slopes (AB, AC or BC) has a slope $b$ which is significantly different from 0. If that's the case one can conclude like in an ANOVA that there is at least one group in which height is significantly different from one or more groups. Afterwards, one could use a post-hoc test of course to test which of the groups really differ. Is my understanding of how the regression models tests this hypothesis correct?

Like, I don't get it. In regression, we say  $$Y_i = a + bX_i + \epsilon$$ where $X_i$ is just a real number for each observation $i$,  and in analysis of variance with two groups, we say $$Y_i = a + bX_i + \epsilon$$ where $X_i$ is again just a real number, but this time either 0 (group 1) or 1 (group 2), so a is mean of group 1, and a+b is mean of group 2.  But despite the interpretation, the model is exactly the same. So why do people split it up into regression and anova? the model is the same?


I am want to dig in that whether it is an ambiguity or an extra feature that is provided:   public class Foo   {      public int Bar(){        //code     }      public string Bar(int a){        //code     }  }   Any one having any experience with this, overloading on return type with different parameters should be a bad practice, is it?  But if the overloading was done on the basis of return type then why this is not working for.    public class Foo   {      public int Bar(int a){        //code     }      public string Bar(int a){        //code     }  }   As it will be unable to decide which function to call 1st or second, if we call obj.Bar(); , it should end in error do any one have any idea about it why it allows first code snippet to run.

Why don't more mainstream statically typed languages support function/method overloading by return type?  I can't think of any that do.  It seems no less useful or reasonable than supporting overload by parameter type.  How come it's so much less popular?


I am studying the counterpart of the axiom of choice in ETCS which is that "Every surjective fucntion has a right inverse". I am trying to see why it implies the axiom of choice and this is the paragraph i am studying at the moment. Let  $f: X \rightarrow Y$ be the surjective function and $g: Y \rightarrow X$ be the right inverse. Noticing that a surjective function represents a non empty set  of a disjoint non empty set and that disjoint sets are  $f^{-1}(y)$ for each $y$ in $Y$. Then $g: Y \rightarrow X$ is a choice for every $y$ in $Y$ as $g$ picks out one element of $f^{-1}(y)$. Therefore, the existence of $g$ is equivalent to the axiom of choice. I can't make sense of the "$g: Y \rightarrow X$ is a choice for every $y$ in $Y$ as $g$ picks out one element of $f^{-1}(y)$". I studied the definition of the axiom of choice as "given a non empty set $A$,  it is possible to choose an element from each subset $a$ in set $A$" I would greatly appreciate any help with this.

This is a problem from Tao's Analysis I.  We are asked to show that the axiom of choice is equivalent to the statement that for any sets $A$ and $B$ for which a surjection $g:B\to A$ exists, an injection $f:A\to B$ exists.  I have proven that the axiom of choice implies the statement , but I am having difficulty with the other implication. The hint given in the book is to use the previous exercise, which says that the axiom of choice is equivalent to the statement that if $I$ is a set, $\forall\alpha\in I$ $X_\alpha$ is a non-empty-set and $\forall \alpha,\beta\in I, \alpha\neq \beta\implies X_\alpha\cap X_\beta=\emptyset$, then there exists a set $Y$ with $\forall \alpha\in I ,|Y\cap X_\alpha|=1$.  To use the previous exercise we need disjoint sets, so we consider the sets $\{\alpha\}\times X_\alpha$ instead of just $X_\alpha$. I think then we should find a set $Y$ with $\forall \alpha \in I,|Y\cap(\{\alpha\}\times X_\alpha)|=1$, perhaps by using that there is some surjection between two sets and so by assumption some injection which goes the other way, whose image is suitable as a set $Y$. I think that is the idea, but I can't figure out exactly what these functions should be.  If I am incorrect, please correct me. Any help is appreciated.


Some particular independent variable has low p (high t value) as a linear regressor. That means (if I understand correctly) that I can trust it has some effect on the dependent variable, and then I look to see what effect it has. Normally I would take the coefficient from the regression output and divide it by the mean value of the dependent variable to see the effect. But the r2 of the line is very low. Does that mean I should throw the whole thing out? or how then do I see the effect of the independent variable? To put it another way, if most of the variability is unexplained by the independent variables, then is the effect properly measured by dividing the regression coefficient by the dependent variable's mean, or does one need to account somehow for the r2 when measuring the effect?    Someone has asked me for more information.  R-square    0.494 Adj R-square    0.451 Residual SD 2.107 Sample SD   2.845 N observed  194 N missing   10          Estimate    Std. Error  t value Pr(>|t|) 0       1,614.974   290.998 5.550   < 0.0001 a       -0.118  0.406   -0.291  0.7717 b       -0.745  0.440   -1.693  0.0923 c       1.161   0.578   2.009   0.0461 d       -2.194  1.104   -1.988  0.0484 e       0.001   0.034   0.031   0.9751 f       -0.009  0.165   -0.057  0.9549 g       -1.289  0.812   -1.588  0.1141 h       0.665   0.648   1.027   0.3058 i       -0.601  0.595   -1.011  0.3132 j       -0.101  0.420   -0.240  0.8109 k       -0.466  0.947   -0.492  0.6233 l       0.057   0.395   0.144   0.8856 m       0.496   0.677   0.732   0.4648 n       -1.009  0.862   -1.170  0.2437 o       -0.037  0.007   -5.478  < 0.0001

As far as I understand, a high F-stat leads to a high $R^2$, though the converse is not true. What does it mean if I have a high F-stat and a low $R^2$?


I'm trying to put some information and a table (\starttabulate...\stoptabulate) aside to a image, the image in the left column and the title and the table in the right column. So what I did is this:  \definecolumnset[doscolumnas][n=2] \setupcolumnset[doscolumnas][1][width=.2\makeupwidth]  \startcolumnset[doscolumnas] \externalfigure[programacion-semanal][width=.15\makeupwidth] \column {\bfd Programación semanal}\par  \starttabulate[|j1r|j1r|j2r|l|] \NC  1 \NC 15 \NC  2 \NC Academia \NC \NR \NC  4 \NC 11 \NC 15 \NC Cultura \NC \NR \stoptabulate   \stopcolumnset  But both columns still appear with the same width size! I'm using the very latest version of ConTeXt, but I don't know if is this something I did wrong (I was following the Columns documentation at ). Can anyone give me a clue about this? Thank you so much!

In LaTex I build the following macro "kum" for translating arabic to german. The result are two minipages, left one with german, right one with arabic (the other two minipages were for design-issues). The macro "arab" is not shown, it just choose an arabic font.  \newcommand{\kum}[2]{ \begin{minipage}[t]{0.445\textwidth} \small #1 \end{minipage}  \begin{minipage}[t]{0.05\textwidth}   ~ \end{minipage} \begin{minipage}[t]{0.445\textwidth}  \begin{arab}[voc] \raggedleft #2 \end{arab} \end{minipage} \begin{minipage}[t]{0.06\textwidth}  ~ \end{minipage} }   Now I've two questions:   What is the equivalent of minipages in ConTeXt? How to realize the above LaTeX code in ConTeXt? (both with engine LuaTeX)


Is there a notation to refer to all the n element subsets of a set? I know the power set denotes all of the subsets.

How would one denote the set of all subsets of $A$ which have size $2$?  Would  $$\binom{A}{2}$$  be a good idea?


I have a large equation  \begin{document}  \begin{gather} W = \frac{1}{2\mu_0}(\frac{\Psi'^2 \pi^2}{b^2} \sum_{m,n} a_{mn}^2 n^2 (ab/4) + \frac{\Psi'^2 \pi^2}{a^2} \sum_{m,n} a_{mn}^2 m^2 (ab/4) + \Psi'^2ab(\mu^2 + \sum_{m,n} \frac{8a_{mn} \mu^2}{\pi^2 mn} + \frac{a_{mn}^2 \mu^2}{4})) \notag \\[1ex] W = \frac{\Psi'^2 ab}{2\mu_0}(\mu^2 + \sum_{m,n} [ \frac{a_{mn}^2}{4}(\frac{m^2 \pi^2 }{a^2} + \frac{n^2 \pi^2}{b^2} + \mu^2) + \frac{8a_{mn}\mu^2}{\pi^2 mn}]). \label{eq:energycart} \end{gather}  \end{document}   On my document settings the first equation JUST goes off the expected margin and as a result is not centred in the middle of the page (the left side stays on the margin, the right side goes off). Is there anyway to centre the equation, even if it goes out of the margins? I don't want to split the equation on to two lines.

I understand the reasoning behind the fairly narrow textwidth in a default LaTeX article. 60-80 characters per line and all that. However, I am preparing a document that features many lengthy equations, and it seems silly to me to restrict the equations to fit into the same margins as the text when there's all that whitespace going unused on either side.  I'd like to have equations which are wider than the textwidth do the obvious thing, that is, continue to be centered on the page just like all the other equations, and simply extend into both the left and right margin equally. My equations are unnumbered, so there's no concern about where to put equation numbers.  How might I go about implementing this?


I read a sentence in "The Hindu" which was:     Coming as it did just after the success of The Shape of Water at the Oscars, the book became an instant bestseller.   I don't know what difference would it have made had I not used "as it did" after "coming".

Islamic law is the result of an examination, from a religious angle, of legal subject matter that was far from uniform, comprising as it did the various components of the laws of pre-Islamic Arabia and numerous legal elements taken over from the non-Arabnpeoples of the conquered territories.


I have two NSURLRequest objects, connecting to a web service and invoking 2 different services.  The problem is that I have a random results, sometimes the first one is displayed first and sometimes the second NSURLRequest is the first.  NSString *urla=@"http://localhost:8080/stmanagement/management/retrieve_dataA/?match_link="; NSString *uria = [urla stringByAppendingString:self.lien_match]; NSURL *urlla= [ NSURL URLWithString:uria]; NSURLRequest *requesta =[ NSURLRequest requestWithURL:urlla];  NSString *urlb=@"http://localhost:8080/stmanagement/management/retrieve_dataB/?match_link="; NSString *urib = [urlb stringByAppendingString:self.lien_match]; NSURL *urllb= [ NSURL URLWithString:urib]; NSURLRequest *requestb =[ NSURLRequest requestWithURL:urllb];  connectiona=[NSURLConnection connectionWithRequest:requesta delegate:self]; connectionb=[NSURLConnection connectionWithRequest:requestb delegate:self];  if (connectiona){     webDataa=[[NSMutableData alloc]init]; }  if (connectionb){     webDatab=[[NSMutableData alloc]init]; }   Is that correct what I'm doing? Should I add a small break between the two NSURLRequests?   Because at every view execution I have a random result. (I'm setting the results to two UITableView objects).

I have a ton of repeating code in my class that looks like the following:  NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request                                                               delegate:self];   The problem with asynchronous requests is when you have various requests going off, and you have a delegate assigned to treat them all as one entity, a lot of branching and ugly code begins to formulate going:  What kind of data are we getting back? If it contains this, do that, else do other. It would be useful I think to be able to tag these asynchronous requests, kind of like you're able to tag views with IDs.   I was curious what strategy is most efficient for managing a class that handles multiple asynchronous requests.


I recently got a new 3TB hard drive which I plan on loading up with video files on my Window PC and then transfering the hard drive to my Linux PC/server.  I formatted the drive as NTFS (since I was told that NTFS is compatible in both environments) and partitioned the drive as GPT (since I read this was also compatible in both environments), but, even though it detects the drive on my Linux PC, I'm getting an error when trying to access it which reads:  Error mounting /dev/sdb2 at media/me/LONGSTRINGOFNUMBERSANDCHARACTERSTHATIBELIEVEISHEXIDECIMALCODE: Command-line 'mount-t "ntfs" -o "unhelper=udisks2,nodev,nosuid,uid=1000,gid=1000" "/dev/sdb2" "media/me/SAMELONGSTRINGASABOVE"' exited with non-zero exit status 14: The disk contains an unclean file system (0, 0). Metadata kept in Windows cache, refused to mount.  Failed to mount '/dev/sdb2': Operation not permitted. The NTFS partition is in an unsafe state. Please resume and shutdown Windows fully (no hibernation or fast restarting), or mount the volume read-only with the 'ro' mount option.   Anybody have any idea what this means? What I have to do to fix this??

Whenever I boot Ubuntu, I get a message that it cannot mount my windows partition, and I can choose to either wait, skip or manually mount.  When I try to enter my Windows partition through Nautilus I get a message saying that this partition is hibernated and that I need to enter the file system and properly close it, something I have done with no problem so I don't know why this happens.    Here's my partition table, if any more data is needed please let me know.     Device Boot      Start         End      Blocks   Id  System /dev/sda1            2048    20000767     9999360   83  Linux /dev/sda2        20002814   478001151   228999169    5  Extended /dev/sda3   *   478001152   622532607    72265728    7  HPFS/NTFS/exFAT /dev/sda4       622532608   625141759     1304576   82  Linux swap / Solaris /dev/sda5        20002816   478001151   228999168   83  Linux


After upgrading to macOS Catalina, the download progess indicator changed to an IOS-style circle, which doesn't give the more specific details of download speed and time remaining that were visible in previous versions. Is there any way to still see how long an app will take to download/upgrade?

I am using macOS Mojave which features a major redesign of the Mac App Store app. When installing app(s) from the new Mac App Store, how do I check the status of download(s) in progress?  It is possible to check the progress of downloads in the Purchases tab in the previous design of the Mac App Store, but that appears to be no longer available in the redesign.  Has this been removed in the redesign?


Is there an extension to $n$ dimensions of the usual spherical coordinates mapping a three-dimensional sphere to a two-dimensional rectangle?  [Duplicate]:

What's the analogue to spherical coordinates in $n$-dimensions? For example, for $n=2$ the analogue are polar coordinates $r,\theta$, which are related to the Cartesian coordinates $x_1,x_2$ by  $$x_1=r \cos  \theta$$ $$x_2=r \sin  \theta$$  For $n=3$, the analogue would be the ordinary spherical coordinates $r,\theta ,\varphi$, related to the Cartesian coordinates $x_1,x_2,x_3$ by  $$x_1=r \sin  \theta  \cos  \varphi$$ $$x_2=r \sin  \theta  \sin  \varphi$$ $$x_3=r \cos  \theta$$  So these are my questions: Is there an analogue, or several, to spherical coordinates in $n$-dimensions for $n>3$? If there are such analogues, what are they and how are they related to the Cartesian coordinates? Thanks.


I am a beginner in latex. I want to draw a table in latex. But, unfortunately, the last vertical lines are discontinuous. Is there a way to fix it?  Latex Code:  \begin{tabular}{||c||c||}     \hline \hline \\[-0.2cm]     \textbf{Duration of course} & Month/Year - Month/Year\\[0.1cm] \hline \\[-0.2cm]     \textbf{No. of credits} & $\#$ of credits\\[0.1cm] \hline \\[-0.2cm]     \textbf{Course Slot} & slot letter allocated to the course, if slotting system is followed\\[0.1cm] \hline \\[-0.2cm]     \textbf{Course Timings} & Day: Time slot\\[0.1cm] \hline \\[-0.2cm]     \textbf{Evaluation Pattern} & Evaluation Pattern and Weightage\\[0.1cm] \hline \\[-0.2cm]     \textbf{TAs} & Name of TA, Designation, Roll no:\\[0.1cm] \hline \\[-0.2cm]     \textbf{Course Overview} & Overview of the course\\[0.1cm] \hline \hline \end{tabular}   Output:

I'm dealing with the powerful tabularx environment. I was able to obtain a nice table, except for the last column. I need seven columns in total, but at the end I got another half column. I can't understand why!  Here the code I used for building the table:  \begin{table}[h!]  \begin{tabularx}{\textwidth}{|l|*{20}{>{\arraybackslash}X|}}  \multicolumn{1}{c}{}& \multicolthead{3}{\color{RoyalBlue}\textbf{I}}& \multicolthead{3}{\color{RoyalBlue}\textbf{II}} & \multicolthead{3}{\color{RoyalBlue}\textbf{III}} & \multicolthead{3}{\color{RoyalBlue}\textbf{IV}} & \multicolthead{3}{\color{RoyalBlue}\textbf{V}} & \multicolthead{3}{\color{RoyalBlue}\textbf{VI}} \\  \hline  \thead{\color{RoyalBlue}One\\\color{RoyalBlue} Time} & \cellcolor[HTML]{D3D3D3} & \cellcolor[HTML]{D3D3D3} & & \multicolumn{3}{l|}{} & \multicolumn{3}{l|}{} & \multicolumn{3}{l|}{} & \multicolumn{3}{l|}{} & \multicolumn{3}{l|}{} \\  \hline  \thead{\color{RoyalBlue}Two\\\color{RoyalBlue} Times} & & & \cellcolor[HTML]{D3D3D3} & \cellcolor[HTML]{D3D3D3} & & & \multicolumn{3}{l|}{} & \multicolumn{3}{l|}{} & \multicolumn{3}{l|}{} & \multicolumn{3}{l|}{} & \\  \hline  \thead{\color{RoyalBlue}Three\\\color{RoyalBlue}Times} & \multicolumn{3}{l|}{} & & \cellcolor[HTML]{D3D3D3} & \cellcolor[HTML]{D3D3D3} & \cellcolor[HTML]{D3D3D3} & \cellcolor[HTML]{D3D3D3} & \cellcolor[HTML]{D3D3D3} & \cellcolor[HTML]{D3D3D3} & \cellcolor[HTML]{D3D3D3} & \cellcolor[HTML]{D3D3D3} & \cellcolor[HTML]{D3D3D3} & & & \multicolumn{3}{l|}{} \\   \hline  \thead{\color{RoyalBlue}Four\\\color{RoyalBlue} \& Times} & \multicolumn{3}{l|}{} & \multicolumn{3}{l|}{} & \multicolumn{3}{l|}{} & \multicolumn{3}{l|}{} & & \cellcolor[HTML]{D3D3D3} & \cellcolor[HTML]{D3D3D3} & \cellcolor[HTML]{D3D3D3} & & \\  \hline  \end{tabularx} \caption{{Caption}} \end{table}   Which produces the following output:    Does anyone have an idea?