I wish to apply for an MS in CS in the United States or Canada for Fall 2022. I am from non-CS background (engineering physics) and currently work as a software developer. I had programming experience in college and took undergrad courses in data structures, algorithms and machine learning. But I have not taken core CS courses like operating systems, compilers or computer architecture. If I take any online courses on these topics and mention the certificate link in my statement Of purpose, can it help boost my profile? Considering the fact that I would need to start applications 6 months from now, I was wondering if such online courses are worth the time now. If yes, can someone suggest online courses on these topics which have the same level of rigor as an undergraduate course?

I see places like Coursera, Udacity and EdX offer certificates upon successful completion of course work. Also most of the people doing recorded teaching at these places are famous and well known professors.  So if someone mentions those kind of course certificates in CV or application material for grad school, does it have a significant value for the applicant?   Do you consider these kind of certificates at the same level with a grade on an academic transcript?


I have a server application written in ASP.NET on Windows that provides a web service.  How can I call the web service in Linux with cURL?

I wish to send a header to my Apache server on a Linux box.  How can I achieve this via a cURL call?


I am from Mumbai, India. I will soon go on a short trip to the UK on a 6m business visa. Am planning to take my wife and two kids (7 years and 2 years) along for some sightseeing over the weekends. My wife cannot speak fluent English as she has studied in vernacular medium. What visa will be required for her and my kids? Will it be dependent on my visa or independent? Also, does it matter in the Visa application if she is not good at English? Just to add, we will be there for 2-3 weeks.

I am resident of India and just got UK Business visa ( 6 months, multiple entry) .. I am going for a week on business trip. I want to take my wife along with me and at the end of trip.. I want to extend my trip for 3 days and we want to spend some time on leisure.   What visa I should apply for my wife.. visitor visa? should she mention in the visa form that she is going along with me and staying with me while I am on work and later we are spending time on leisure.   While filling my business visa form, there was a field asking if anyone else is going with me.. I selected no.. as there were no plans.  Also is it ok to spend time on leisure on UK Business visa


I'm working on a sub-theme of Bootstrap Barrio, which includes a table.css stylesheet. I don't want this stylesheet from the parent theme to be included in my sub-theme.   How do I eliminate a CSS file from sub-theme's parent?

I am trying to override the menu.css file in the default Classy theme through my library file. I have read through the documentation, but anything I tried doesn't work.  What would be the correct markup to override or disable this file?


Say I have earned 1000 points on StackOverflow, how can I find out how many of them were from asking questions, giving answers, editing posts, etc.

When I visit the reputation tab of my profile, I see a lot of stuff. I can make out some of it, but not all.   What do all the event types mean? Why do some events show an odd reputation gain or not show any reputation change at all? Why are some events sometimes highlighted in yellow? My reputation suddenly dropped, but I don't see anything. What happened? Why do some events disappear from my reputation history?


I have a simple Android app with 2 activities and a base activity where I store a global array of images.  The ImageGrid activity displays a grid of images that the user can touch/click to display a larger version of that image.  When clicked, ImageGrid sends the selected index of the image that was touched to the selectedImage activity.  However, everytime it does that, I get this error:     java.lang.NullPointerException: Attempt to invoke virtual method 'void   android.widget.ImageView.setImageResource(int)' on a null object   reference      Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void   android.widget.ImageView.setImageResource(int)' on a null object   reference                         at SelectedImage.onCreate(SelectedImage.java:19)   Line 19 is this:  int arrNum = arrPosition;   I've stepped through the debugger, and I do see the index position getting passed and set, so I'm at a loss as to why I'm getting a NullPointerException.  Here is the BaseActivity:  public class BaseActivity extends AppCompatActivity {      Integer[] ApocImages =  {R.drawable.image1, R.drawable.image2, R.drawable.image3, R.drawable.image4,             R.drawable.image5, R.drawable.image6, R.drawable.image7, R.drawable.image8,             R.drawable.image9, R.drawable.image10, R.drawable.image11, R.drawable.image12,             R.drawable.image13, R.drawable.image14, R.drawable.image15, R.drawable.image16}; }   ImageGrid:  public class ImageGrid extends BaseActivity {      ImageView gridThumbnail;     @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_image_grid);         GridView grid = findViewById(R.id.gridView);         final ImageView selectedImage = findViewById(R.id.imgLarge);         grid.setAdapter(new ImageAdapter(this));          grid.setOnItemClickListener(new AdapterView.OnItemClickListener() {             @Override             public void onItemClick(AdapterView<?> parent, View view, int position, long id) {                 Intent myIntent = new Intent(ImageGrid.this, SelectedImage.class);                 int arrPos = position;                 myIntent.putExtra("selectedImage", arrPos);                 startActivity(myIntent);             }         });     }      public class ImageAdapter extends BaseAdapter {         private Context context;          public ImageAdapter(Context c) {             context = c;         }          public int getCount() {             return ApocImages.length;         }          public Object getItem(int position) {             return null;         }          public long getItemId(int position) {             return 0;         }          //gets the view for each item in the array         public View getView(int position, View contentView, ViewGroup parent) {             // populate gridview with imageview of each photo in array             gridThumbnail = new ImageView(context);             gridThumbnail.setImageResource(ApocImages[position]);             gridThumbnail.setScaleType(ImageView.ScaleType.FIT_XY);             gridThumbnail.setLayoutParams(new GridView.LayoutParams(330, 300));             return gridThumbnail;         }      } }   SelectedImage:  public class SelectedImage extends BaseActivity {      @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         Context appContext = getApplicationContext();         final ImageView selectedImage = findViewById(R.id.imgLarge);          Intent intent = getIntent();         int arrPosition = intent.getIntExtra("selectedImage", 1);          int arrNum = arrPosition;         selectedImage.setImageResource(ApocImages[arrNum]);         selectedImage.setClickable(true);          selectedImage.setOnClickListener(new View.OnClickListener() {             @Override             public void onClick(View v) {                 //startActivity(new Intent(SelectedImage.this, ImageGrid.class));                 finish();             }         });     } }

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?


helper.method_name worked in some version of Rails... are there ways that work in both Rails 2.2.2, 2.3.5, and 3.0.1?  (to use all view and helper methods)

When I load script/console, sometimes I want to play with the output of a controller or a view helper method.  Are there ways to:   simulate a request? call methods from a controller instance on said request? test helper methods, either via said controller instance or another way?


I have imported an object from a JS file to another JS file, using import/export keywords. This forced me to give the linked script in the HTML the propertie : <script type="module" src="modules/test.js"></script> //exported object <script type ="module" src="Wallet.js"></script> //imported object  Now , I have noticed that when I do this , many functions from the imported file stop working and the HTML events that rely on JavaScript are never read. Suddendly I have errors , like " Function is X is not defined at HTML.element.onmouseover" I know this was working before and stopped when I introduced the import/export and module type. What is the reason for that?

What is the scope of variables in javascript? Do they have the same scope inside as opposed to outside a function? Or does it even matter? Also, where are the variables stored if they are defined globally?


I have seen some Linux scripts having Shebang different from the file extension.  Ex:   somefile.sh has #!/bin/bash inside it somefile.ksh has #!/bin/sh inside it somefile.bash has #!/bin/sh inside it   Can someone tell me what is proper naming convention to be followed while mentioning file extension and Shebang inside it?

On wikipedia, the article for  says:      For the .sh file extension type, see .   How about other unix shells?  I know that the   is used inside the file to indicate an interpreter for execution, but I wonder:    What are the pros and cons for files extensions vs no file extensions?


I'm the sole author of a paper and in my introduction I've written:     We are able to talk about... Doing so we manage to capture ... We accomplish this by embedding...   and I'm wondering whether it's correct to talk about myself in the plural like that, similar to the way that mathematicians tend to write when talking about some mathematical fact or proof. If not do I just write things like "I am able to talk about"? Because that just sounds odd.

I commonly want to use the phrase "we have" when writing mathematics, to mean something like "most readers will know this thing and I am about to use it". My primary question is whether this is too colloquial. My secondary question is what the alternatives are if it is too colloquial.  For example, right now I have a sentence "Given a point $P\in X$ we have the residue map ${\text {res}}_P \colon \Omega_{K(X)} \rightarrow k$, as defined in ...". I don't feel saying "there exists the" is quite right. Even if it is grammatically correct, I don't think this conveys the implication that it will be almost certainly familiar to the expected audience.  I have seen  but I feel this is slightly different. If not then my apologies.


We are "cloud-sourcing" all our services (web, databases, file storage, e-mail, print, DNS).  As authentication is made on the could-provider side, I'm wondering about the pro and cons to keep our Active Directory domain controller.  For info, we are a small organization with about 50 users (50/50 laptop-travelers / destop office based).

Taking a spin off of this question:  in a new direction for 2014.  Taking into account a basic Windows infrastructure:   domain controllers Exchange 2007/2010/2013 Sharepoint SQL File Servers / Print Servers AD Integrated DNS AD authenticated 3rd party devices (let's say 802.1X for networking and maybe some content-filtering, etc.) AD/LDAP authenticated "administrative" functions on IT apps/hardware/etc. perhaps some KMS stuff throw in a CA if you'd like home grown apps 3rd party in-house apps   Now, let's rip it all out and decide we are going to the cloud.  We've contracted to move Exchange/Sharepoint/File Services to Office 365.  SQL will now be hosted as well on  something like Azure.  We've gotten away from the need for AD-DNS and simply run everything via a simple Windows DNS server.  We still need 802.1X and would like SSO if possible to our various cloud apps.  Home grown and 3rd party in-house apps would likely stay, but have the ability to use internal user databases instead of AD authentication  The question is...do we really need Active Directory at all?  Or more to the point, AD on-premise or even hosted via Azure or similar (ADFS) or running ADDS on a hosted VM through Azure or similar.  Could/Should we look to something else like a 3rd party SSO option such as  or similar that can provide SSO functionality even if it is as simple as LastPass or similar for each user?  What kind of legitimate needs does AD fulfill if everything else in the cloud?  Could a MS-centric infrastructure get away with not having AD at all if they move everything that previously relied on AD to SaaS offerings that didn't rely on AD authentication?


A = [5,3,1,4,2]  4.downto(1) do |i|   0.upto(i) do |j|     #here i am making the actual buble sort      if A[j] > A[j + 1]       tmp = A       A[j + 1] = A[j]       A[j] = tmp     end   end end  #just printing the array A.each do |i|   print i end  gets()   Does someone know why does it happen? I just don't know where is the nil element.  I've tried everything, I know but I'm learning and I can't find the error.   Thanks for your help, also there is another little problem, when I try to make the for loop it doesn't work, it's not a big deal because there are more than one way to make the same thing, but still...

I have just started the MIT Introduction to Algorithms course through the material posted online. Along with the course I have also decided to learn/enhance my Ruby skills by coding the algorithms in it.   I am on the first algorithm given, which is Insertion sort, and I have the following code typed up but I am getting this error when I run it:     insertionsort.rb:5:in `>': comparison of Fixnum with nil failed (ArgumentError)   def  insertionsort(num) for j in 2..num.length     key = num[j]     i = j - 1     while i > 0 and num[i] > key         num[i+1] = num[i]         i = i - 1     end     num[i+1] = key end  puts num end  numbers = [23,34,46,87,12,1,66]  insertionsort(numbers)   I'm sure it is a fairly basic problem but I just can't grasp what it is at the moment. Any  help or tips would be very much appreciated.


I am currently writing a Bash script, and I found the exact answer to my programming question here:    Note that the question I used is currently closed as off-topic.  I have seen that the debate is that Bash questions belong on SuperUser or Unix/Linux, unless you paste the exact same commands into a .sh file and run it.  (See: Tim Post's answer on  for example) This seems pretty illogical to me for the following reasons:   There is no difference between bash scripting and bash typing other than the time period in which you type the commands (ahead-of-time or real-time as you need them). The question is exactly the same whether you're typing it out in real time or typing it into a Bash script.  In fact, many Bash programmers will try individual commands live on the command line to make sure they work properly before pasting them into the script.  Literally the exact same question could be made "on-topic" on SO by just pre-pending this sentence to the question: "I'm currently writing a Bash script and...".  In other words, it isn't the question that we care about it, it is the context, when the context doesn't change either the question or the answer?  What if future programmers writing a Bash script have the same question but never see it because they don't want to search 4 different sites for where some random mod thinks it is most on-topic (there can be arguments made that Bash questions belong on SO, SuperUser, Unix&Linux, and AskUbuntu.  What if I'm typing my Bash commands in real-time (so not into a script) on an Ubuntu machine...)?  Major dilemma... Bash is a very commonly used programming tool.  For many of the programmers I work with, Bash/Vim or Bash/Emacs is their IDE.  SO is a site for programmers. People tend to post questions/seek answers on whichever site they are most familiar with.  So, if someone isn't a programmer, but writes Bash scripts as part of their system administrator job, their questions would naturally be more related to SuperUser or Unix/Linux.  On the other hand, people writing Bash scripts for programming purposes tend to look here on SO.  This is a natural sorting algorithm that helps address the problem of many legitimate overlapping jurisdictions.   Can we not be so quick to throw away excellent questions that benefit a lot of people (as evidenced by the high vote counts and comments expressing frustration and outrage at their closure), and instead focus our efforts on generating awesome content and bouncing the questions that clearly need to go (such as the "Do you haz teh codez")?

I'm going to put this question out for people to review as I've gotten into a discussion with another member concerning the 'legitimacy' of the existence of questions regarding batch files on SO.  Although, he has not made a cogent argument to date, I thought I'd put it up here for discussion.   Should questions regarding bat file programming be moved to SF due to their not being programming questions?   Addendum- There have been several good points made comparing batch file scripting and ?nix scripting.  Are there any rational reasons for moving those questions over to SF or SU as well?  And, if it is reasonable to move batch file scripting over and not ?nix, why?


I rescued Dexion and he immediately began attacking me.  Serana beat him down and we got out of the cave, but he was outside with us and began attacking again.  Serana beat him down again and I was able to fast travel to the Dawnguard hold.  He was inside and was attacking everyone.    I've tried:   changing his faction setting his hostility to 0 teleporting him outside the hold   One of the above console commands did something to him because now he's just standing still, but he's "busy", so I cannot interact with him.  I no longer have the auto save from before I rescued him, so I am going to need some console magic to fix this.

So whilst going to rescue the Moth Priest 'Dexion Evicus', I think I accidentally might have hit him, not sure how. Anyhow the bearded maniac has taken this as a personal attack and refuses to accept a yield. Because he's so angry with me he'll just not quit, but being a quest NPC he can't die, nor can my companion Mjoll. So aside from the hilarious infinity battle, I thought, fair enough I'll talk to him whilst he's 'downed' and lo, I progressed the quest.  So I go back to the Dawnguard fortress, and he's there in the middle shouting murder and attacking everyone in the fortress! Clearly his rage knows no bounds.    Is there a way to forcibly pacify him without interring him? Or do I need to roll back and do over?


A game is played with a collection of $n \geq 1$ beans. The beans are first divided into piles. A move consists of taking a bean from each pile, and forming a new pile with these beans. This process is repeated indefinitely. So, for example, if 12 beans were divided into piles of 3, 4, and 5 beans, then after one move there would be piles with 2, 3, 3, and 4 beans, and after another move there would be piles with 1, 2, 2, 3, and 4 beans. A collection of piles of beans is stable if making a move does not change the number of piles of any given size. So, for example, three piles of sizes 1, 2, and 3 would form a stable collection. Prove that if n beans can be divided into a stable collection of piles then n = 1 + 2 + · · · + k, for some positive integer k.

Let we have $n\cdot(n+1)/2$ stones grouped by piles. We can pick up 1 stone from each pile and put them as a new pile. Show that after doing it some times we will get the following piles: $1, 2, \ldots n$ stones.  Example: $n = 3$  Let we have 2 piles with 3 stones of each.  $$3 3 \to 2 2 2 \to 1 1 1 3 \to  2 4 \to 1 3 2$$


The diagram that I am providing depicts a pile of bricks. I have the border and brick the color of BurntOrange. I would like the border to be three times the default line width of the \draw command. Is the default line width 0.4pt?  \documentclass{amsart}  \usepackage[dvipsnames]{xcolor} \usepackage{tikz} \usetikzlibrary{calc}  \begin{document}   \noindent \begin{minipage}{4.5in} \noindent \raggedright{\textbf{5.) }The following figure depicts a stack of bricks. A bricklayer \\ intends to number every brick that is not in the bottom \\ row with the sum of the numbers on the two bricks \\ supporting it. What is the number that will be \\ put on the top brick?} \end{minipage} % \hspace{-0.5cm} % \raisebox{0mm}[0mm][0mm] { \begin{tikzpicture}[baseline=(current bounding box.west)]   %A pile of bricks is drawn. \draw[draw=BurntOrange, line width=1.2pt, fill=BurntOrange!75] (0,0) -- (0.75,0) -- (0.75,0.5) -- (0,0.5) -- cycle; %\node at (0.375,0.25){18}; \draw[draw=BurntOrange, line width=1.2pt, fill=BurntOrange!75] (0.75,0) -- (1.5,0) -- (1.5,0.5) -- (0.75,0.5) -- cycle; \node at (1.125,0.25){7}; \draw[draw=BurntOrange, line width=1.2pt, fill=BurntOrange!75] (1.5,0) -- (2.25,0) -- (2.25,0.5) -- (1.5,0.5) -- cycle; %\node at (1.875,0.25){15}; \draw[draw=BurntOrange, line width=1.2pt, fill=BurntOrange!75] (2.25,0) -- (3,0) -- (3,0.5) -- (2.25,0.5) -- cycle; %\node at (2.625,0.25){17}; \draw[draw=BurntOrange, line width=1.2pt, fill=BurntOrange!75] (3,0) -- (3.75,0) -- (3.75,0.5) -- (3,0.5) -- cycle; \node at (3.375,0.25){3}; \draw[draw=BurntOrange, line width=1.2pt, fill=BurntOrange!75] (0.375,0.5) -- (1.125,0.5) -- (1.125,1) -- (0.375,1) -- cycle; \node at (0.75,0.75){25}; \draw[draw=BurntOrange, line width=1.2pt, fill=BurntOrange!75] (1.125,0.5) -- (1.875,0.5) -- (1.875,1) -- (1.125,1) -- cycle; %\node at (1.5,0.75){22}; \draw[draw=BurntOrange, line width=1.2pt, fill=BurntOrange!75] (1.875,0.5) -- (2.625,0.5) -- (2.625,1) -- (1.875,1) -- cycle; \node at (2.25,0.75){32}; \draw[draw=BurntOrange, line width=1.2pt, fill=BurntOrange!75] (2.625,0.5) -- (3.375,0.5) -- (3.375,1) -- (2.625,1) -- cycle; %\node at (3,0.75){20}; \draw[draw=BurntOrange, line width=1.2pt, fill=BurntOrange!75] (0.75,1) -- (1.5,1) -- (1.5,1.5) -- (0.75,1.5) -- cycle; %\node at (1.125,1.25){47}; \draw[draw=BurntOrange, line width=1.2pt, fill=BurntOrange!75] (1.5,1) -- (2.25,1) -- (2.25,1.5) -- (1.5,1.5) -- cycle; \node at (1.875,1.25){54}; \draw[draw=BurntOrange, line width=1.2pt, fill=BurntOrange!75] (2.25,1) -- (3,1) -- (3,1.5) -- (2.25,1.5) -- cycle; %\node at (2.625,1.25){52}; \draw[draw=BurntOrange, line width=1.2pt, fill=BurntOrange!75] (1.125,1.5) -- (1.875,1.5) -- (1.875,2) -- (1.125,2) -- cycle; %\node at (1.5,1.75){101}; \draw[draw=BurntOrange, line width=1.2pt, fill=BurntOrange!75] (1.875,1.5) -- (2.625,1.5) -- (2.625,2) -- (1.875,2) -- cycle; %\node at (2.25,1.75){106}; \draw[draw=BurntOrange, line width=1.2pt, fill=BurntOrange!75] (1.5,2) -- (2.25,2) -- (2.25,2.5) -- (1.5,2.5) -- cycle; %\node at (1.875,2.25){207};   \end{tikzpicture} }   \end{document}

Is there some macro that will tell me what the default PGF line width is? I have tried creating my own macro by cloning \pgflinewidth before it has been modified, i.e.  \let\defaultlinewidth\pgflinewidth   but \defaultlinewidth seems to be affected by \pgfsetlinewidth anyway, and change to whatever \pgflinewidth is. So, the problem is that after I have called \pgfsetlinewidth, I don't know what the default pgf line width is anymore. Is there some way to get around this?


I have been suggested Artin or Herstein's books. What do you think is more rigorous but at the same time clear and good to read?

I was wondering if some one here would please recommend an abstract algebra text book. In particular, I am seeking a text from among one of these:  1) Abstract Algebra by Dummit and Foote  2) Algebra by Michael Artin  3) Topics in Algebra by Herstein.  I was wondering which text is best for a high school student and has great exposition and good problems. My goal is study some algebraic number theory some time later in the near future as I liked elementary number theory.


What is the fundamental group of  $\mathbb S^2$ attached with a diameter? And what is the fundamental group of a hemisphere attached with a diameter?  I guess for the latter one, we can deformation retract it to a circle by compressing around the diameter. So the fundamental group should be $\mathbb Z$. And for the first one we can combine this result with Van Kampen's theorem, and the answer should also be $\mathbb Z$.  Am I right? And how can I prove the case for hemisphere more rigorously?

Consider the quotient space obtained by identifying the north and south pole of $S^2$. I think the fundamental group should be infinite cyclic, but I do not know how to prove this.   If it is infinite cyclic, would this and $S^1$ be an example of two spaces which have isomorphic fundamental groups but are not of the same homotopy type?


I propose allowing posting new comments on any post I already have comments on, even if I drop below the rep threshold for the comment-privilege (50 rep) later.  And maybe also always allow responding to any ping (editors, dupe-hammer-wielders and mod-closers can be pinged even if they never commented).    Background: I recently made  on a post. Shortly thereafter, I put bounty on another one of my questions, which brought my reputation below 50. Then, when  was posted, I was unable to respond because of the requirement that I have at least 50 reputation to comment.

After offering a bounty to , I realize that I cannot comment on the question because I no longer have the required reputation. Is it possible to change this behavior, so that the bounty owner can comment only on the post with the bounty irrespective of their reputation? While bounty owners are told that they'll lose privileges at the time they place a bounty, it makes sense to allow them to interact with potential answerers/commentators to help solve the problem, or at least provide additional information.


I would like to create a popup window as an action button in my Opportunity layout that will show details from my Opportunity and its related Contacts and Clients. I imagine this must be done via Visualforce. Could someone help me do this or point me in the redirection on how I can achieve this?  I'd imagine this would invole a Visualforce page and an apex class.

We currently use the lead detailed page to display lead information. We have a requirement where we need to create a custom button on the lead detailed page on the standard layout where on clicking the button, we need to display additional attributes of the lead on a popup panel on the same detail page. We currently do this on a visual force page which opens a new window every time. What we want to display is a modal window on the standard page layout or a popup panel where we can embed a visual force page and display some more attributes and on clicking a button, the popup disappears the detail page is rendered. Do any of you guys have examples of doing this or sample code might help? Buyan


(refused latter UK embasy)  The decision :  i have refused your application for a visit visa because I am not satisfied that you meet the requirements of paragraph 4.2 of appendix V : immigration rules for visitors because:   you stated that you wish to visit the UK for 6 days as a tourist. under the UK immigration rules you must show that you are qualify for a visa by explaining your own circumstances and the plans you have for visit.it is your responsibility to satisfy me that they are such that if guaranteed leave to enter you will abide by all of the conditions attached to any such leave and that you will leave the United Kingdom on completion of proposed visit. You state that you are unemployed. You have stated that you are traveling withe your spouse and that he is funding your visit.you have not stated that how you are supported.you have provided property documents withe your application but this documents do not dimostrareate that you drive an income from them.i also note that when your spouse received his uk visa last October he stated that he had an online business. The documents you have provided do no demonstrate this business or that you or your spouse receive and income such a business. The documents you have provided do not demonstrate how you support your self in bangladesh and as such I am not satisfied that they are an accurate reflection of your financial circumstances in bangladesh On the evidence available to me today, I am not satisfied that your circumstances are as stated in your application. Therefore I am not satisfied that you are a genuine visitor to the UK for a purpose that is permitted by the visitors rules or that you intend to leave the uk at the end of your proposed trip (appendix V: 4.2 a c   I am going to reapply. What was wrong with my previous application? What do I need to provide in addition to other documents so as to ensure that I get the visa? What was wrong with my earlier application and what corrective steps should I take for my next application?   thanks in advance  Farhana Rumpa

Many of the UK visa refusals we see here share a common pattern and the prevailing reasons refer to V 4.2 (a) and (c).    I do understand that, while the applicants may describe very different individual circumstances, there's a consistent pattern and, broadly, fall into specific categories:    Credibility (lifestyle, lack of ties, visit history, lies & omissions) Funding (insufficient funds, provenance of funds, funds parking) Sponsorship (family, friends, employer)   Question: What most commonly triggers a UK visa refusal where V 4.2 (a) and (c) are given as the grounds?  Secondarily: Given that there is a clear pattern, to what extent are these refusals predictable? Does sponsorship make a difference? Is there a set of personal circumstances, however abstract, where a refusal is all but guaranteed? For example, why do those we see here on TSE who sought entry for the PLAB or British Army appear to be refused with a common theme? Is there a uniform shortcoming or is it just discrimination?   PLAB: What is about applications for a visa, for the purpose of sitting the Professional and Linguistic Assessments Board (PLAB) exam, that seem to invite refusals. After all, the test is given so that international medical graduates can show that they qualify to practise medicine in the UK. The first part, PLAB 1, can be taken in centres outside of the UK. However, PLAB 2 can be taken only in the UK. Why can't you can't get a visa just to sit the exam, promising that you'll leave immediately after?    British Army: Since Commonwealth citizens are eligible to apply online to join, even those who don't reside in the UK, why is it so difficult to get a visa just to attend an interview to see whether you are suitable? Even with an invitation from the Army, such visa applications seem to be unsuccessful. Isn't a career in the British Army a valid reason?     Lastly:  After such a refusal, what approaches would increase the chance of a successful application?


I get a lot from Stack Overflow, I want to contribute to others' questions too, but numerous .net, html questions come to the front page, while what I am good at is c and linux. How to filter those questions and just show questions related to my favorite tags?

What are watched tags and ignored tags? How do they work? What are tag subscriptions? What are interesting tags? On Stack Overflow, the content of the main page question list appears to be influenced by watched and ignored tags. How does that work?   For more information, see "" in the .


I am ashamed to ask that but it is making me crazy. I try to push an array into another array as follow: var person = {"bla":"46","bla2":"46","bla3":"46"}; var test = {"bla4":"46","bla5":"46"}; person.push(test);  Well it is not working and I don't see why. Can someone see what I am doing wrong and maybe have the good way to proceed ? thanks

I need to be able to merge two (very simple) JavaScript objects at runtime.  For example I'd like to:  var obj1 = { food: 'pizza', car: 'ford' } var obj2 = { animal: 'dog' }  obj1.merge(obj2);  //obj1 now has three properties: food, car, and animal   Does anyone have a script for this or know of a built in way to do this?  I do not need recursion, and I do not need to merge functions, just methods on flat objects.


I've been using blender for a month or so , but now I've noticed that all the animation renders , i make , simple or complex , they all have low quality.I was following ducky3ds  environment tutorial , but all my animations were low quality. please help me increase the quality of this render coz i didn't expect this. for , info the render is in eevee , blender 2.3.

If I just render the default cube it will look like this:   It is rendered with color depth 16. I can see there are artefacts consisting of visible "line strokes" on some of the cube faces.  The bands seems to not go darker and darker, but alternates between light and dark, or is my eye fooled?  Why?  Edit  Here comes a gradient created by gimp without banding, using the same computer:


I need to specify a password with the character #, but it comments the line. How do I force it to be be read literally?  Ex : I need to put PASSWORD=xpto#123. Without commenting the 123

Or, an introductory guide to robust filename handling and other string passing in shell scripts.  I wrote a shell script which works well most of the time. But it chokes on some inputs (e.g. on some file names).  I encountered a problem such as the following:   I have a file name containing a space hello world, and it was treated as two separate files hello and world. I have an input line with two consecutive spaces and they shrank to one in the input. Leading and trailing whitespace disappears from input lines. Sometimes, when the input contains one of the characters \[*?, they are replaced by some text which is is actually the name of files. There is an apostrophe ' (or a double quote ") in the input and things got weird after that point. There is a backslash in the input (or: I am using Cygwin and some of my file names have Windows-style \ separators).   What is going on and how do I fix it?


I've done a good amount of research on this and put together this command, but it appears to be finding the directories that HAVE scanned.txt not the directories that don't have scanned.txt. How can I Modify this to fit my needs? find . -type f -maxdepth 2 -not -name 'scanned.txt' -exec dirname {} \; | sort -u >> NOT_SCANNED.txt  Thanks

How would I go into listing all directories that do not have a file with a given file name inside? e.g. given this tree  /   /a      README      file001      file002   /b      README      file001   /c      file003   I want to list the directories that do not have a file named README, in this case it would be directory /c. How would I do that? I can't think of any syntax using e.g. find.


In a google sheet I have some values that are used in formulas in other cells (until now, nothing unusual...).   I would like these cells to have a special color to be aware that if I modifiy them, other cells will be modified as well. Is there a function to test if a cell's value is used elsewhere?  I am looking for a simple built-in way to do this, without macros, and I just need to know wether the cell is used elsewhere or not, not by whom, or neither what it does.  Thanks for your help

I would like to find out which cells have formula dependencies in a large spreadsheet. I am looking for a way to do something like OpenOffice     Tools>Detective>Trace dependents   and     Edit>Find & Replace>Search in formulas   or a way to create a trigger in GAS that gets called when a given cell value is referenced and can identify the source of the reference.


I have a table with following hypothetical data:  ID | Name    | managerId ---|---------|----------- 1  | James   | 2 2  | Martin  | 4 3  | Huges   | 5 4  | Richard | NULL 5  | Kavin   | 4 6  | Rita    | 3   In the above table we have:  Richard is manager of Martin is manager of James.  Richard is manager Kavin is manager of Huges is manager of Rita.  Now I have to select immediate manager and grand manager of an employee in this table. I mean if we start from Rita I have to select Huges (immediate manager) and Richard(grand manager).  How to do that. I have no clue at all.  EDIT: There isn't any specific levels of managers. An Employee can have 'n' Number for managers in hierarchy where n ϵ {0,1,2,3.....}

Assume you have a flat table that stores an ordered tree hierarchy:  Id   Name         ParentId   Order  1   'Node 1'            0      10  2   'Node 1.1'          1      10  3   'Node 2'            0      20  4   'Node 1.1.1'        2      10  5   'Node 2.1'          3      10  6   'Node 1.2'          1      20   Here's a diagram, where we have [id] Name.  Root node 0 is fictional.                          [0] ROOT                           /    \                [1] Node 1          [3] Node 2               /       \                   \     [2] Node 1.1     [6] Node 1.2      [5] Node 2.1           /            [4] Node 1.1.1   What minimalistic approach would you use to output that to HTML (or text, for that matter) as a correctly ordered, correctly indented tree?   Assume further you only have basic data structures (arrays and hashmaps), no fancy objects with parent/children references, no ORM, no framework, just your two hands. The table is represented as a result set, which can be accessed randomly.   Pseudo code or plain English is okay, this is purely a conceptional question.  Bonus question: Is there a fundamentally better way to store a tree structure like this in a RDBMS?    EDITS AND ADDITIONS  To answer one commenter's ('s) question: A root node is not necessary, because it is never going to be displayed anyway. ParentId = 0 is the convention to express "these are top level". The Order column defines how nodes with the same parent are going to be sorted.  The "result set" I spoke of can be pictured as an array of hashmaps (to stay in that terminology). For my example was meant to be already there. Some answers go the extra mile and construct it first, but thats okay.  The tree can be arbitrarily deep. Each node can have N children. I did not exactly have a "millions of entries" tree in mind, though.  Don't mistake my choice of node naming ('Node 1.1.1') for something to rely on. The nodes could equally well be called 'Frank' or 'Bob', no naming structure is implied, this was merely to make it readable.  I have posted my own solution so you guys can pull it to pieces.


Here's some examples. Please tell me which ones are right, and which ones are wrong, and why.   "A 350-meter asteroid impacted the Moon." "A 350-meters asteroid impacted the Moon." "A 350 meter asteroid impacted the Moon." "A 350 meters asteroid impacted the Moon."   There's also extended versions.   "A 350-meter wide asteroid impacted the Moon." "A 350-meter-wide asteroid impacted the Moon."   Etcetera. Which ones are right/wrong, and why?

I can ask any of:     Do you know a breakfast place nearby?   Do you know a nearby breakfast place?   Do you know a good breakfast place?   but I really can't ask:     Do you know a breakfast place good?   Is there a general rule for determining whether an adjective must come before the noun or may come, Spanish-style, after it?


I recently installed Ubuntu 18.04 and I'm not keen on the desktop environment. I want the desktop env. I used to have in Ubuntu 14.04. How can I get it?  I've attempted to use , but when I try to install the Unity's 7.2.5 version using the command:  apt install unity=7.2.5   it gives me   E: Version '7.2.5' for 'unity' was not found   For sure I need to add a PPA for this, but which one!?

Now, that Ubuntu 17.10 is out, and Unity 7 is replaced with Gnome 3, is there a way to install and use Unity7?   I know Unity is still in the repositories, so it should be possible, right?


Let $f$ and $g$ be entire functions such that $e^f + e^ g=1$ then how to show $f$ and $g$ are constant. I am having trouble in proving these. any help would be appreciated. Thanks in advance.

Prove if $f$ and $g$ are entire and $e^f+e^g=1$, then $f$ and $g$ are constant.  I believe the simplest way would be to use Louiville's theorem by using Pick's theorem but I am not sure on how to go about this.


Can anybody explain which are the optimization algorithms used in latex, that make the difference with wysiwyg editors, like msword?

I want to learn more about the implementation of TeX's text-justification algorithm (setting the glue).   After scanning through ch.12 of Knuth's TeXbook, I'm guessing that setting the glue must consist in a constrained linear program   whose variables represent the interword glue, and whose constraints correspond to shrinks & stretches allowed for each interword glue.   However, if my intuition is correct, the linear program in question must get prohibitively large pretty quickly as the length of the document increases, at least, for computers back in the day. Does setting the glue use some heuristic instead?  EDIT: Thanks to egreg for his . However, I realise I should have included the paragraph-making algorithm in my question.  I'm still not quite clear on the interplay between   the paragraph-making algorithm (which, I presume, determines where line breaks occur), and the text-justification algorithm (which determines the interword glue).   It seems to me that the two problems are not independent. Does the paragraph-making algorithm, in the process of generating line break after line break, not use information about each glue item (natural width, stretch and shrink components), too?


I answered a question on Stack Overflow and the user keeps asking for more and more help. Can I opt-out from notifications of that particular question?

Related:    Today, we had . This sort of sparked me into coming up with a new feature-request (Can't find a dupe, surprised).  Basically, we should have more control over what does and does not appear in the multicollider. This includes:   Muting comments and/or answers on a specific post. Muting comments from a specific user Ignoring all comments not addressed to you in a post of yours (I don't think this is that good, though--many times comments address both the OP and the other guy). Ignoring certain chat rooms The ability to make answers/comments on posts written by others to ping your multicollider.   Note that "Mute" could mean that it shows up in the inbox, but doesn't trigger the colorful glowing circle on the multicollider.    With the new "notifications" thing, there may be some scope in making certain notifications opt-in or opt-out (not all of these exist, but many would be useful in the notifications tab):   Notification of rejected edit Notification of  posts Notification of change to favorites Notification of certain badges Notification of edits Notification of edits to posts you have upvoted Notification of edits to posts you have downvoted (yes, should be separate)  - Notification of edits to posts you have closevoted


I have two objects Opportunity and approval__c that are related. One Opportunity can have multiple approval_c. I would like for each opportunity that have an Approval to return a list containing a mix of Opportunity data and Last approval Data. So I planned to do two list 1 for the Opportunity, one for the Last approval and merge them together. However I am not sure on how to get the data about the last approval. my code looks like: @AuraEnabled(cacheable=true)     public static List<Object> approvalTableData(){         List<Object> FinalList = new List<Object>();         List<AggregateResult> OppList = [SELECT Opportunity__r.Id  FROM Approval__c                                       WHERE (Type__c = 'Investment_Committee' OR Type__c = 'Pre_IC')                                      AND Status__c != Null                                      AND CALENDAR_YEAR(Date__c) = 2021                                      GROUP BY Opportunity__r.Id];                  for(AggregateResult item: OppList){             List<Opportunity> OppData = [SELECT Id, Name, StageName                                          FROM Opportunity                                          WHERE Id = :item.Id];                          List<AggregateResult> LastApproval = [SELECT max(date__c) FROM Approval__c GROUP BY Opportunity__c];             system.debug(LastApproval);                          List<Approval__c>ApprovalList = [SELECT Id, Status__c, date__c                                               FROM Approval__c                                               WHERE Opportunity__r.id = :item.Id                                               and Type__c = 'Pre_IC'                                              ];             system.debug(ApprovalList);         }                                             return OppList;              }  It looks like a very bad practice, but I am kinda lost could you please help me

I would like to merge multiple List into one but I am not sure on how to do it .. My code is the following: public with sharing class ApprovalDashboard {     public ApprovalDashboard(){              }          @AuraEnabled(cacheable=true)     public static List<Object> approvalTableData(){         List<Object> FinalList = new List<Object>();         List<AggregateResult> OppList = [SELECT Opportunity__r.Id  FROM Approval__c                                       WHERE (Type__c = 'Investment_Committee' OR Type__c = 'Pre_IC')                                      AND Status__c != Null                                      AND CALENDAR_YEAR(Date__c) = 2021                                      GROUP BY Opportunity__r.Id];                  for(AggregateResult item: OppList){             List<Opportunity> OppData = [SELECT Id, Name, StageName                                          FROM Opportunity                                          WHERE Id = :item.Id];                          List<Approval__c>ApprovalList = [SELECT Name, date__c FROM Approval__c WHERE Opportunity__r.id = :item.Id];             system.debug(OppData);         }                                             return OppList;              }  I would like to mege OppData and ApprovalList into one big List in the format [{}, {},{}] .. Any help ?


For some reason I can no longer upload a picture anywhere on the Stack Exchange network. When prompted to "Drag and Drop or Click here" to upload a picture, the prompt is unresponsive. I also cannot add a link to the photo.  As well as the above symptoms, small red text is constantly displayed on the bottom of the window saying, "Your image is too large to upload (over 2 MiB)", before I've even upload a picture yet. In fact, this "bug", is the very thing preventing me from providing a picture of this undesired behavior.  My current browser is Google Chrome, Version 56.0.2924.87 (64-bit). Could anyone confirm if this is something local to me - or if this is affecting all users?

When I try to upload an image, I'm presented with the following dialog box,    The dialog box does not allow uploading either from my computer or by posting a link.  This happens only on Chrome browser (running on Windows). Clearing cache and cookies, and restarting computer do not resolve.  Is this just my computer? Or is this a site-wide bug?  Additional info:  Clicking on 'click' to upload does nothing. Dragging an image onto dialog redirects me to the file location on my computer. Clicking 'Add picture' redirects me to http://[SE-domain].com/upload/image?https=true.  UPDATE: A Norton extension for Chrome was the source of the problem.


I'm using a table to show a comparison of two 64-bit blocks/strings — bit for bit. Like so:            Without the table it of course fits comfortably with room to spare, but when we draw the tables, extra space is added between each value on account of the minimum width of each cell. However, we can override this minimum width by putting \setlength{\tabcolsep}{1.0pt} between \begin{table} & \begin{tabular}. You can go all the way down to 0.0pt (probably even further if you really wanted to), and each cell gets its sides squished in. At 0.5pt, it will fit nicely between my 1.25in margins, but any bigger, it will be flush with the left margin, and overhanging the right.  I'd like to know how to get the table to ignore the margins and become truly centered, relative to the center of the current page. It shouldn't affect anything other than the table (surrounding text for instance). Just a quick temporary override. I thought it was possible with a minipage environment to get a float to.. well float, but I'm not having much luck.  Here's my MWE for the image above:     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \documentclass[a4]{article} \usepackage{booktabs} \usepackage{colortbl} \usepackage{xcolor} \usepackage[margin=1.25in,a4paper,showframe]{geometry} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \makeatletter \newcommand*{\yncellcolor}{} \def\yncellcolor\ignorespaces{\@ifnextchar{1}{\cellcolor{green!20}}{\@ifnextchar{0}{\cellcolor{red!20}}{}}} \newcolumntype{C}{>{\yncellcolor}c} \makeatother %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \begin{document}\tiny %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \begin{table} \centering \begin{center}     \setlength{\tabcolsep}{1.0pt} \begin{tabular}{|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|C|}  \hline 1 & 0 & 0 & 0 & 1 & 1 & 0 & 0 & 1 & 0 & 1 & 0 & 0 & 1 & 1 & 0 & 0 & 1 & 0 & 0 & 1 & 1 & 0 & 1 & 1 & 1 & 1 & 0 & 1 & 0 & 0 & 1 & 1 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & 1 & 0 & 1 & 1 & 0 & 0 & 0 & 1 & 0 & 0 & 1 & 0 & 0 & 0 & 1 & 1 & 1 & 0 & 1 & 0 & 0 & 1 & 1 & 1 \\ \hline 0 & 1 & 1 & 1 & 0 & 0 & 1 & 1 & 0 & 1 & 0 & 1 & 1 & 0 & 0 & 1 & 1 & 0 & 1 & 1 & 0 & 0 & 1 & 0 & 0 & 0 & 0 & 1 & 0 & 1 & 1 & 0 & 0 & 0 & 1 & 1 & 1 & 1 & 1 & 0 & 0 & 1 & 0 & 0 & 1 & 1 & 1 & 0 & 1 & 1 & 0 & 1 & 1 & 1 & 0 & 0 & 0 & 1 & 0 & 1 & 1 & 0 & 0 & 0 \\ \hline  \end{tabular} \end{center} \end{table} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \end{document} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     Please, no obvious suggestions about font size, etc. Thanks.

I have a document containing a table which is slightly too wide for the page. But instead of growing to the right side only, I would like to have it centered on the page.  I have tried to use the center environment but this doesn't seem to help.


I want to grab some feature services from ArcGIS Hub and put them on a GDB on my local PC. Here's the code that I've got so far:   import arcpy  # Set project directory proj_dir = 'C:\\Users\\rhard2\\Documents\\am_ml_mainlines_v_01'  # Grab online data (feature services): from arcgis.gis import GIS gis = GIS()  # Connect to AGOL LA_geological_faults = gis.content.get(('4bb7809eac534689b36b2d347ac96220')) LA_streets_cl = gis.content.get(('d3cd48afaacd4913b923fd98c6591276')) LA_streets_width = gis.content.get(('13c2f36f37894faa8ecc918b29f9b156'))  # Return items (feature services) above: display(LA_geological_faults, LA_streets_cl, LA_streets_width)  # Set out location for the containers container_1_gdb = os.path.join(proj_dir,'container_1.gdb')  # Place them to container_1.gdb arcpy.FeatureClassToFeatureClass_conversion(in_features=LA_geological_faults, out_path=container_1_gdb, out_name='LA_geological_faults', config_keyword="") arcpy.FeatureClassToFeatureClass_conversion(in_features=LA_streets_cl, out_path=container_1_gdb, out_name='LA_streets_cl', config_keyword="") arcpy.FeatureClassToFeatureClass_conversion(in_features=LA_streets_width, out_path=container_1_gdb, out_name='LA_streets_width', config_keyword="")   But this gave me an error:     RuntimeError: Object: Error in executing tool   Questions:  I read somewhere (I couldn't find the link) that FeatureClasstToFeatureClass is supposed to support feature service. What have I done wrong? How do I download a feature service layer and put them into a GDB in my computer?   I use ArcGIS Pro 2.4

I am trying to export/copy a feature service to a local geodatabase where I can work on it locally.    I have provided the code below. I keep getting an "Object: Error in executing tool" for the last line where I am trying to copy the feature.   from arcgis.gis import GIS from arcgis.features.use_proximity import create_buffers  import arcpy  #########################################################################################  GDB_Name = input("Name Geodatabase")  Folder_Input = input("Provide Folder Path of Project")  Item_ID = input("Provide item ID")   #########################################################################################  gis = GIS("http://arcgis.com", "XXXXXXXX", "XXXXXXXXXXX")  search_results = gis.content.search('{}'.format(Item_ID))  Trail_Data = search_results[0]  WorkspaceGDB = arcpy.CreateFileGDB_management(Folder_Input, '{}.gdb'.format(GDB_Name)) print("GDB created")  arcpy.env.workspace = r'{}'.format(WorkspaceGDB)  arcpy.CopyFeatures(Trail_Data, "Area_Trail_Data")


Does taking the power goes from left to right or from right to left? For example, what is 2^2^3?   According to a textbook I was reading, all operations are executed from left to right, which would make me think that 2^2^3 =$(2^2)^3=4^3$. However, my calculator says it is equal to $2^{(2^3)}=2^8=256$.

Does $x^{y^z}$ equal $x^{(y^z)}$? If so, why?   Why not simply apply the order of the operation from left to right? Meaning $x^{y^z}$ equals $(x^y)^z$?  I always get confused with this and I don't understand the underlying rule. Any help would be appreciated!


Now, the Half-Blood Prince movie had far too many flaws, but the most nonsensical and unnecessary change is Dumbledore's surprise at the Horcrux memory.  In the book Dumbledore already knew about the Horcruxes and needed the memory only as confirmation to how many there were. In the movie, though, it seems as though he's shocked by the discovery after he sees the memory and yet he's already destroyed the ring. So that doesn't really make sense IMO. I mean, how come he's already destroyed the ring if he didn't know about the Horcruxes?

In Harry Potter and the Half-Blood Prince, Dumbledore orders Harry to retrieve the memory about the talk with Tom Riddle/Voldemort from Slughorn. The memory is said to be needed because it contains valuable information that is needed to defeat him. The result is that they know that Voldemort uses Horcruxes.  Why do they not know this before? If the knowledge about Horcruxes is present in school books (albeit forbidden section) and teachers, then surely some magical academics will already have guessed that Voldemort would try to use them?  Also, if I recall correctly, there is a hint in the first book, "some thought that he was no longer alive enough to be able to really die" which hints a lot at the split soul as a price you pay for being immortal.  Why does Slughorn's memory seem so crucial to Dumbledore?


I have played games like diablo 2 or never winter nights, and there you could trade your weapons for gold.  I have been playing Dark Souls 2 in xbox but I can't find anyone to trade my useless weapons and armors.  what can I do with my unused stuff?

I just started playing Dark Souls 2 without playing the first one.  Since I don't see any sell option in any merchant: Can I sell my old-unused-equipment for souls? If I cannot sell it, does it have any value to be keep until later?


The function getdata() works fine without the template but when I put the template in I get this error Severity    Code    Description Project File    Line    Suppression State Error   LNK2019 unresolved external symbol "public: char const * __thiscall json_map::getdata<char const *>(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >)" (??$getdata@PBD@json_map@@QAEPBDV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z) referenced in function _main    banking   struct declaration in header file: struct json_map {      std::map<std::string, std::any> data;      template<typename A>     A getdata(std::string key);  };  function declaration: template<typename A> A json_map::getdata(std::string key) {     return std::any_cast<A>(data[key]); }  function use: map1.getdata<std::string>("walid");

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


I have seen many folks doing this  concluding that shadow from point A on the Moon can travel to point B on the Moon faster than light.  What I fail to understand here (and I am sure I am wrong), is nothing can travel faster than light. I also read about Relativity where Einstein stated that every event happening for you depends on how fast the light gets from where the event is happening to you.  This is my particular problem with this Moon shadow experiment. You cannot make a shadow travel faster than light, because in order for the "disappearance" of light to get to the Moon, it has to travel at light speed.  Here is one way to understand my point. Consider we shine a flashlight on Moon, like the guy in the linked video did, we move the finger across the face of the flashlight, before we moved the finger it was casting the shadow at Point A on Moon, after we finish moving our finger, the shadow is at Point B on the Moon.  When the finger reaches the end of it's moving length, the light waves that have left the flashlight before the finger reached there will have to hit Point B and it will take them a second and a half to get there, and another second and half for us to see that shadow on point B, which makes it 3 seconds + finger moving time for us to actually see the shadow at point B. That means shadow traveled (say) across the diameter of the Moon in 3 seconds.   So. about 3000 Km in ~3 seconds make it 1000 Km per seconds which is very tiny compared to the speed of light. How can these experiments conclude that Shadow could be made to travel faster than light? What is the obvious clue that I am missing here?

Minutephysics has a popular  called "How to break the speed of light". In the video it states that if you flick your wrist while pointing a laser that reaches the moon, that the spot of light on the moon will travel 20 times the speed of light. Now don't get me wrong, I do like their videos, just this one seemed a bit fishy to me. At first I thought it all practically made sense, then I realised something...  In my mind, I would think that light particles (photons) travel from the laser to the moon and bounces off the moon and back to your eye (it doesn't just stay there, in place, so you can't move it around). Now, what he is stating is that if you flick your wrist these photons that have travelled to the moon will move along with your wrist. Wouldn't these photons be bouncing off of other objects or still travelling to the moon by the time you flick your wrist? i.e. dissipating, therefore new photons will be travelling to the moon (from the laser directly).  For example: let's say you point the laser at the moon, and once it reaches the moon, you wait a couple of seconds and then flick your wrist. The laser that you have flicked will emit photons in every direction that your wrist was in, correct? i.e. The photons would shoot out in a straight line (unless disrupted) continuously, with your wrist taking no affect on the speed of the photons.  So back to the question, is this video wrong?


I am trying to revert my PHP version to 5.6 from 7 and though I removed PHP 7 and then installed PHP 5.6 I still seem to be running version 7.  Is there a simple method for moving through PHP versions where apache, phpMyAdmin and co are configured appropriately?  A simple way to change the current version of PHP on the fly and even site by site would be great.

I am trying to update to install PHP 5.5, 5.6 or 7.0 in Ubuntu 12.04/14.04/16.04 LTS, and I can only get PHP 5.3.10 for Ubuntu 12.04, PHP 5.5.9 for Ubuntu 14.04 or PHP 7.0.4 for Ubuntu 16.04 using official repositories (using apt-get).  I'm not really sure how to do a manual update – as I need:   to play around with the new(est) PHP features to install older PHP version due support in the software


I am looking for a proof for why $\mathbb{C}$ and $\mathbb{R}$ are isomorphic under addition. I understand the outline of the proof; one shows that $\mathbb{R}$ forms a vector space over $\mathbb{Q}$, and $\mathbb{C}$ forms a vector space over $\mathbb{Q}$, and then show that both these have a basis with infinite dimension. However, I would like to see a rigorous proof. Does anyone have a good source for a proof of this?

I think the answer is yes.   Sketch of the proof Consider $\mathbb{R}$ as a vector space over $\mathbb{Q}$. Let $\{e_\lambda:\lambda\in\Lambda\}\subset\mathbb{R}$ be its Hamel basis. Then $\{(e_{\lambda_1},e_{\lambda_2}):\lambda_1,\lambda_2\in\Lambda\}\subset\mathbb{R}^2$ is a Hamel basis of $\mathbb{R}^2$. Consider set theoretic bijection $i:\Lambda\to\Lambda\times\Lambda$ define map $\varphi:\mathbb{R}\to\mathbb{R}^2$ by its action on element of Hamel basis of $\mathbb{R}$ by equality $\varphi(e_\lambda)=(e_{i(\lambda)_1},e_{i(\lambda)_2})$. This is an isomorphism between $\mathbb{Q}$-vector spaces $\mathbb{R}$ and $\mathbb{R}^2$.  Question Could you tell me is this proof correct, and if it is not, where is the mistake?  EDIT: Thanks to GAJO we found that this proof is wrong. The correct one basis is  $$ \{(e_\lambda,0):\lambda\in \Lambda\}\cup\{(0,e_\lambda):\lambda\in\Lambda\} $$ So we had to look at bijections of the form $i:\Lambda\to\Lambda\coprod\Lambda$ and the desired linear operator is defined by equalities $\varphi(e_\lambda)=(e_{i(\lambda)},0)$ if $i(\lambda)$ lies in the first copy $\Lambda$ and $\varphi(e_\lambda)=(0,e_{i(\lambda)})$ otherwise.


Let $T:\Bbb R^4\longrightarrow\Bbb R^4$ be a linear transformation satisfying $T^3+3T^2=4I$, where $I$ is the identity transformation. Then the linear transformations $S=T^4+3T^3-4I$ is a). one-one but not onto. b). onto but not one-one. c). Invertible. d). Non-invertible.  on solving i get $S=4T-4I$, but how does this suggest invertibilty? Also, Logically thinking option $a,b$, and $d$ are interlinked. So if only one choice is correct then i could simply say that yes option $c$ is correct. But can someone give the general aproach?

Let $T,S$ be linear transformations, $T:\mathbb R^4 \rightarrow \mathbb R^4$, such that $T^3+3T^2=4I, S=T^4+3T^3-4I$. Then S is:   one-one but not onto onto but not one one invertible non-invertible   (One or more correct options)  My attempt: $S=T^4+3T^3-4I=T(T^3+3T^2)-4I=T(4I)-4I=4T-4I$  How do I go about proving or disproving my options?   My thoughts on options # 1. and 2.: I'm guessing $S$ is one-one if $Ker(S)=\theta$ is one way to go, but how do I obtain the kernel when I don't know what the transformation is? $Ker(S)=\theta$ if $T=I$, which does satisfy $T^3+3T^2=4I$. But so can other $T$s.   My thoughts on options # 3. and 4.: $S$ is invertible if $det(S)\neq0$, which is possible $det(T-I)\neq0$, i.e. $T\neq I$. How do I show that?  Please help!


Can anyone help me out and tell me what the icon circled in red is please as I have no idea Thanks in advance

I have an HTC One with Sprint, and I believe this icon appeared after the 4.3 update.  I have gone through the list of apps (both running and total) but nothing appears to match up.  Other friends with Android phones don't appear to have this icon, but they all root and customize 7893 ways.  Can anybody identify this icon?


Let $(X,d)$ be a metric space. How to prove that every lindelöf metric space is separable?

Let $(X, \mathcal{T})$ be a metrizable space. Prove that $X$ Lindelöf   implies that $X$ is separable.   My attempt:  Let $d$ be the metric that induces the topology $\mathcal{T}$.   For every $n \geq 1$, consider the open cover: $$\{B_X(x,1/n)\mid x \in X\}$$  Because the space is Lindelöf, this implies that for every $n \geq 1$, there is a countable (or finite) subcover given by $$\mathcal{B}_n:= \{B_X(x,1/n) \mid x \in I_n, |I_n| \leq |\mathbb{N}|\}$$  Now, define $D:= \bigcup_{n\geq 1} I_n$. Let $y \in X$. Let $\epsilon > 0$. Choose $m$ a positive integer so large that $1/m < \epsilon$.  Because $y\in X =\bigcup\mathcal{B}_m$, it follows that there exists $x \in D$ such that $y \in B_X(x,1/m)$, meaning that $d(x,y) < 1/m < \epsilon$, such that $x \in B_X(y, \epsilon) \cap D$. Hence, $y \in \overline{D}$ and it follows that $D$ is a dense countable set in $X$, such that $X$ is separable.  Is this correct?


Newbie question here.  I shot an image in low light in jpeg format and it's crisp, but when I shoot raw in plain day at 1/125, my image looks blurry most of the time. Unless I max out the sharpness gain, and even so they're not as crisp as when shot directly in jpeg or using a phone.  Below I have two images for comparison. The first image was shot with the settings to save as JPEG. I shot the second image of the flower in RAW, then saved as JPEG in Adobe Camera Raw without making any edits. The image was shot at 1/125 f25 at 55mm (plus crop factor) with VR enabled. - I don't think at this focal length and speed the movement provoked by pressing the shutter would be an issue, would it?   Both were shot with the same Nikon D5500 DSLR with the basic 18-55 3.5 lens.  I like the flexibility shooting in RAW format gives, but I hate finding all my pictures a bit blurry. What settings do the camera applies when it saves as JPEG and how can I edit my pictures in Camera RAW to achieve the same baseline sharpness ? Is there a good read about the RAW format vs saving in JPEG to get me started ?   Although the DOF is short, the ball that is in the front is very crisp. We can see the dust on the glass bowl.   Image shot in RAW, not as crisp. I am not seeing the details on the petals as much as I would like.   PS. I am aware the two images are hard to compare, but I am using them just to express my question. It's not meant to be a scientific analysis but a means to communicate my question. I have many other images which were shot in RAW and present the same issue. My question is : am I missing something obvious that could explain this ?  Thanks!!!

I've found that when you load a RAW image into an editing program such as Lightroom/Aperture, the image is usually worse than if you just took the image as JPEG. Now I understand that the camera does some magic during the JPEG conversion. But I'm trying to understand what that "magic" is.   If I'm looking to implement that "magic" myself on the desktop, what kind of settings should I be trying? I find that the RAW files have more extreme contrast. The dark areas for example are way darker than JPEG. Why is this? And what is the best way to fix this?


First question ever here... I'm so nervous!  I must display a field (field_asin) in the header of my page.  So I have added this to my template.php file :  function theme_preprocess_html(&$vars) {   $node = menu_get_object();    if ($node && isset($node->nid)) {     $node = node_load($node->nid);      node_build_content($node);     $vars['field_asin'] = render($node->content['field_asin']);   }  }   Now, I can print the field in html.tpl.php with     <?php print $field_asin; ?>   Yep, it works! But how do I choose the display format for this field?  Thanks!  Alex

I'm reading a field value and its format from the database. How would I render that value with the format?


I've come across a question that I don't know how to tackle:     An alternative way of observing Fraunhofer diffraction uses lenses to provide   appropriate conditions. Sketch an optical conﬁguration for observing Fraunhofer   diﬀraction using a point source of light and two lenses.      A parallel beam of light is incident normally on a diﬀraction grating which   consists of a regular array of 200 narrow slits per mm, each slit being 1 µm wide. Light   emerging from the grating is focussed by a lens of focal length 300 mm onto a screen.   The lens and screen are centred on a line perpendicular to the centre of the grating, and   are parallel to the grating. It is intended to observe the 3rd diffraction order with light at   a wavelength of around 460 nm. Where on the screen does this diffraction order appear?   I've done the first part of the question (sketching the optical configuration, with the aperture between two lenses, and the screen and source at a distance f away from each other lenses).  Everything I've learnt about lenses is used to magnify images, and I have no idea how to deal with a ray coming in at an angle. Surely you need to know at what distance the aperture is from the lens?  Any help/hints would be greatly appreciated.

The  treatment of circular apertures yields a diffraction pattern of circles, with the first minimum (dark ring) at an angular radius of $\theta$ where $\sin(\theta)=1.22\lambda/b$, where $b$ is the diameter of the circular aperture.     But this same result is extrapolated to lenses, to calculate its limit of resolution. But in the case of lenses, there is no opaque material which blocks of the light coming out from everywhere except the aperture.      In the absence of this opaque obstacle, how can diffraction take place,   since according to the , the wavefront which would   produce the secondary wavelets still extends everywhere and not just   to a confined region, which is how the diffraction pattern arises, by   confining secondary sources to a finite region or confining it from an   "edge" till infinity?* In other words, Why does putting a circular lens in the path of plane wavefornt produce the same effect as allowing only a circular portion of that wavefront to propagate?      And even if there is diffraction, will the same formulae apply? will   not the presence of light elsewhere change the case?


Is there a way to only be alerted when keywords you've chosen are in the tweet of the person you are following?

How do I receive an alert or create a feed for when a specific Twitter account tweets a specific keyword(s)?  For example, the author of a software application I use apparently does not have any type of feed dedicated to the updates for that software. I'd prefer not to follow his personal feed and monitor for that 1/100+ tweet mentioning the software update. I'd prefer to be notified in some fashion when they tweet a specific keyword. RSS is fine. Other tech/feed is fine.


How to suppress scientific notation from a float value in python. Here I tried the following code but it's not working  r_val[v].append('%.2f' % val.get("closing_balance"))   Thanks in advance

Here's my code:  x = 1.0 y = 100000.0     print x/y   My quotient displays as 1.00000e-05.  Is there any way to suppress scientific notation and make it display as 0.00001? I'm going to use the result as a string.


Upgraded from 13.10 to 14.04. All seemed to go ok, but following reboot I get this message:     Serious errors were found while checking the disk drive for /.   If I ignore that one, I get a further message:     The disk drive for /tmp is not ready yet or not present   And fails to boot. What can I do? Is it possible to do a manual recovery?

I recently installed Ubuntu 14.04 using WUBI and after installation when it booted it showed an error:   Serious errors were found while checking the disk drive for /.    There were three options:   press [I] to ignore, press [S] to skip mounting and press [M] to mount manually.    After I pressed I, it showed /tmp could not be mounted and my Ubuntu isn't booting.   Can anybody please guide me to how to solve this problem?


Everyone,I must launch my code, The first way:  Response.Write("<script>alert('Succeed,Will be redirect to the target page')</script>"); string path = Server.MapPath(@"~\Forms\MainForm_SQL.aspx"); Response.Redirect(path);   The second way:  Response.Write("<script>alert('Succeed,Will be redirect to the target page')</script>"); Server.Transfer(@"~\Forms\MainForm_SQL.aspx");   Now,back to the issue,The question is :  01)it works nothing when using the 'first way',That is, it either alerts the message nor goes into the 'Page_Load' of the target page.  02),when use the second way,it first goes into the 'Page_Load' of the target,than it goes back to alert the message.  why it that so unreachable to track the architecture ? can some one help me please? thanks.

What is difference between Server.Transfer and Response.Redirect?   What are advantages and disadvantages of each? When is one appropriate over the other? When is one not appropriate?


I don't understand how does of mass an object for example say earth causes distortion in space and time. I am just new to this field so it is difficult imagine this phenomenon.

I understand that people explain (in layman's terms at least) that the presence of mass "warps" space-time geometry, and this causes gravity. I have also of course heard the analogy of a blanket or trampoline bending under an object, which causes other objects to come together, but I always thought this was a hopelessly circular explanation because the blanket only bends because of "real" gravity pulling the object down and then pulling the other objects down the sloped blanket. In other words, to me, it seems that curved space wouldn't have any actual effect on objects unless there's already another force present.   So how is curved space-time itself actually capable of exerting a force (without some source of a fourth-dimensional force)?  I apologize for my ignorance in advance, and a purely mathematical explanation will probably go over my head, but if it's required I'll do my best to understand.


I have a large list of tabs which are open in each terminal. I'd need to save them with a meaningful name and restore later when I need them. From what I've checked in another thread you could use: gnome-terminal --save-config However in my gnome-terminal:  $ gnome-terminal --save-config=/tmp/cfg Option "--save-config" is no longer supported in this version of gnome-terminal.  $ gnome-terminal --version GNOME Terminal 3.22.1 Using VTE version 0.46.1 +GNUTLS   Any other option available?

I have a Terminal window with a dozen named tabs open.  I would like to save the current configuration and have it restored with names and directories.  Is there a way to do this?


Okay, so:  I am making an android game. I want everything to scale to the size of the screen I'm using. Further, my static background needs to scale (as well as every other object), but if the aspect ratio is less than the AR of the background image I want the image to be cut off at the edges.  Further, I have a game object I need to always be at the corner of the screen. I'm guessing I should use a script to determine the width of the screen and place it a few coordinates up and right of that on start?  The game is only in landscape mode if that matters. How do I go about this? I previously had the background as a plane with an image on it but it didn't take up the whole screen and I think it might not be the right thing to do? Maybe use a quad?  How do I test to make sure that this works? I only have my one android phone to test it on.

I've gotten a lot of answers to this question, but they are all generic and generally not very useful.  None of the tutorials talk about aspect ratio and dealing with mobile devices and there are a zillion ways to do it, all seem to have gotcha's and flaws.  I really would love to know what successful games have used to handle different aspect ratios on iOS and Android without making a zillion different sized assets.  I am strictly speaking mobile, not desktop, specifically with Unity and I don't care about the UI, I only care about the gameplay canvas.  Issues I have in mind is when there are key things that have to be in certain places and cannot fall off the screen.  Using black bars on top or bottom is unacceptable these days.


prove that if $\lim\limits_{n\to\infty}(a_{n+1}-a_{n})$ exist then $\lim\limits_{n\to\infty}\frac{a_{n}}{n}=\lim\limits_{n\to\infty}(a_{n+1}-a_{n})$ So that's what I did so far  Let $$B_{n}=\frac{(a_{2}-a_{1})+(a_{3}-a_{2})+...+(a_{n+1}-a_{n})}{n}=\frac{(a_{n+1}-a_{n})}{n}$$ and we know that if$\ \lim\limits_{n\to\infty}(a_{n+1}-a_{n})$ exist that's mean that $\lim\limits_{n\to\infty}B_{n}=\lim\limits_{n\to\infty}(a_{n+1}-a_{n})$ Thus we have $\lim\limits_{n\to\infty}\frac{(a_{n+1}-a_{n})}{n}=\lim\limits_{n\to\infty}(a_{n+1}-a_{n})$ But I don't know how to go from here

I have the following problem.   I have to find the limit of $b_n = \frac{a_n}{n}$, where $\lim\limits_{n\to\infty}(a_{n+1}-a_n)=l$  My approach:  I express $a_n$ in terms of $b_n$, i.e. $a_n=nb_n$ and $a_{n+1}=(n+1)b_n$  We look at the difference: $a_{n+1}-a_n=(n+1)b_{n+1}-nb_n$  Assuming that $b_n$ converges to a real number m, we see that:  $l=(n+1)m-nm$, from where I conclude that $m=l$.  What I'm left with is proving that $b_n$ is convergent which I'm not sure how to do.  Thanks in advance!


I copied an equation from Mathematica and I can't change line in the equation but when I write it manually in LaTeX it works fine. Here is the equation that I copied:  \begin{equation}  \begin{multlined} \lambda _3 \sin \left(h_1(t)\right) \sin \left(\cos \left(p_1(t)\right)  \left(\sqrt{R^2-a^2}     \\    h'(t) sin (h(t)) \sin (p(t))-\sqrt{R^2-a^2} \cos (h(t)) p'(t) \cos (p(t))+a p'(t) \sin (p(t))+c h'(t) \cos (h(t)) \sin  (p(t))+c \sin (h(t)) p'(t) \cos (p(t))\right)+p_1(t)\right)  \left(-\sqrt{R^2-a^2} h'(t) \sin (h(t)) \cos (p(t))-\sqrt{R^2-a^2}  \cos (h(t)) p'(t) \sin (p(t))-a p'(t) \cos (p(t))+c h'(t) \cos (h(t))  \cos (p(t))-c \sin (h(t)) p'(t) \sin (p(t))\right)-\lambda _1 \cos \left(h_1(t)\right) p_1'(t) \left(-\sqrt{R^2-a^2} h'(t) \sin (h(t))  \cos (p(t))-\sqrt{R^2-a^2} \cos (h(t)) p'(t) \sin (p(t))-a p'(t)  \cos (p(t))+c h'(t) \cos (h(t)) \cos (p(t))-c \sin (h(t)) p'(t)  \sin (p(t))\right)+\lambda _2 \cos \left(h_1(t)\right) p_1'(t) \left(\sqrt{R^2-a^2} h'(t) \sin (h(t)) \sin (p(t))-\sqrt{R^2-a^2}  \cos (h(t)) p'(t) \cos (p(t))+a p'(t) \sin (p(t))+c h'(t) \cos (h(t))  \sin (p(t))+c \sin (h(t)) p'(t) \cos (p(t))\right)+\frac{1}{2} i  \left(2 \cos \left(h_1(t)\right) p_1'(t)+2 s_1'(t)\right) \end{multlined} \end{equation}   And what are these left and right?

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


With biblatex styles such as authoryear, I can use the starred version of cites commands to omit the author name (for instance \parencite*{key}). How can I do the same with verbose?  More specifically, I only need this in cases where I discuss and cite an author inside a footnote. The following MWE outputs :        Bourdieu argues that blah blah (Bourdieu, La distinction, Paris: Minuit, 1979).      What I want is :        Bourdieu argues that blah blah (La distinction, Paris: Minuit, 1979).      This is what I get if I replace verbose with authoryear:        Bourdieu argues that blah blah (1979).      (Obviously, with authoryear, I would have written "Bourdieu (1979) argues" instead)  \begin{filecontents}{Test.bib} @book{bourdieu1979, author = {Bourdieu, Pierre}, title = {La distinction}, location = {Paris}, publisher = {Minuit}, year = {1979} }  \end{filecontents}  \documentclass{article}  \usepackage[style=verbose]{biblatex} \bibliography{Test.bib}       \begin{document} Here is a footnote\footnote{Bourdieu argues that blah blah \parencite*{bourdieu1979}.}.  \end{document}

Sometimes, I write the name of an author in a sentence before the citation. For this reason, I'd like to suppress it in the citation. How can I do that?  Is the only solution to create a new macro, e.g. \citewoauth, similar to \cite but without author names, or am I missing something? [The MWE (non-working actually) below is with \parencite but the general idea is similar.]    \begin{filecontents}{\jobname.bib}   @article{doe_2011,     title = {A title},     author = {John Doe},     journal = {Journal},     number = {99},     pages = {483--488},     date = {2015},   } \end{filecontents}  \documentclass[12pt,a4paper]{article} \usepackage[utf8]{inputenc} \usepackage[french]{babel} \usepackage[T1]{fontenc} \usepackage{csquotes} \usepackage[style=verbose-trad2,language=french,backend=biber]{biblatex}  \addbibresource{\jobname.bib}  \begin{document} Some text\footnote{According to John Doe, it is \enquote{a complete nonsense} \parencite[485]{doe_2011}}  \printbibliography \end{document}


It's easy for me to fit ARIMA models in software such as R but I cannot find a "simple" example anywhere on the web for how to transform an ARIMA model to state space form (SSF)? I think it's the lagged error term that's causing me trouble here because otherwise I can easily see how to put it in SSF. If someone can step me through this it would be appreciated!!  $$(1-\phi_1B)(1-B)X_t = (1-\theta_1B)\epsilon_t$$  or  $$X_t=(\phi_1+1)X_{t-1}+\epsilon_t-\theta_1\epsilon_{t-1} $$

I have been reading Hamilton Chapter 13 and he has the following state space representation for an ARMA(p,q). Let $r = \max(p,q+1)$.Then the ARMA (p,q) process is as follows: $$ \begin{aligned}  y_t -\mu &= \phi_1(y_{t-1} -\mu) + \phi_2(y_{t-2} -\mu) + ... + \phi_3(y_{t-3} -\mu) \\ &+ \epsilon_t + \theta_1\epsilon_{t-1} + ... + \theta_{r-1}\epsilon_{t-r+1}.  \end{aligned} $$ Then, he defines the State Equation as follows:   $$  \xi_{t+1} = \begin{bmatrix}      \phi_1 & \phi_2 & \dots & \phi_{r-1} & \phi_r \\      1 & 0  & \dots & 0 & 0  \\      \vdots & \vdots & \dots & 0 & 0 \\      0 & 0 & \dots &1 &0 \end{bmatrix} \xi_t  +  \begin{bmatrix}      \epsilon_{t+1} \\     0\\\vdots  \\     0       \end{bmatrix}  $$  and the observation equation as:  $$y_t = \mu + \begin{bmatrix}      1 & \theta_1 & \theta_2 & \dots & \theta_{r-1} \\     \end{bmatrix} \xi_t. $$  I do not understand what the $\xi_t$ is in this case. Because in his AR(p) representation it is $\begin{bmatrix}      y_{t} - \mu \\     y_{t-1} - \mu\\\vdots  \\     y_{t-p+1} - \mu       \end{bmatrix}  $ and in his MA (1) representation it is $\begin{bmatrix}      \epsilon_{t} \\     \epsilon_{t-1}      \end{bmatrix}  $.  Could someone explain this to me a little bit better?


Let $(c,\delta)\in\mathrm{K}^2\subset\mathbb{R}^2$ and $f,g:\mathrm{K}\to\mathbb{R}$ be $C^1$ $$f(c)=g(c),\,f'(x)\geq g'(x)\,\,\forall x\in[c,c+\delta]\implies f(x)\geq g(x)\,\,\forall x\in[c,c+\delta]$$

I need to use this theorem as part of a proof. Basically it goes as follows:  If $f(x_0) > g(x_0)$ and $\frac{d}{dx} f(x) > \frac{d}{dx} g(x)$ for all $x \geq x_0$, then $f(x) > g(x)$ for all $x\geq x_0$.  What's the name of this theorem, if it has one? Or if it doesn't, is there a simple way to prove it that I could include in my proof? Thanks.


I am using code::blocks 12.11 (gcc) on a 32 bit OS. I have the following structure:  struct node  { int a; float b; char d; struct node* c; } s1;   now individually,  sizeof(int);    sizeof(float);    sizeof(char);   gives output 4 4 1 bytes respectively. so i calculate size of structure as 13 bytes. But the following  sizeof(s1); or sizeof(struct node);   gives output 16bytes.  I am unable to figure out why this is so. Please help me out here. Thanks.

Why does the sizeof operator return a size larger for a structure than the total sizes of the structure's members?


I saw this is a known issue in QGIS v3.2 Bonn. I installed QGIS v3.6 Noosa and still have the same issue. For example) csv of .dbf with expected order:  view of attribute table in QGIS:  Any ideas?

I'm having an issue with QGIS version 3.2 Bonn. For my class, a question asks, "What city corresponds to row number 1713 for the Colleges and Universities shapefile?". I'm having issues answering this, because each time I load the shapefile into QGIS, the attribute table order is randomized, giving me a different city each time.   How can I open the "default" version of the attribute table for this layer, so that the order of rows is not randomized each time?


Let $R$ be a UFD if $f\neq 0$ and $\langle f\rangle$ is a prime ideal then $f$  is irreducible. Here is a short and easy proof for this claim but I do not understand the last bit. Assume for a contradiction that $f$ is not irreducible then $f=uv$ where $u$ and $v$ are not units. By $\langle f\rangle$ a prime ideal we have either $f|u$ or $f|v.$ WLOG, assume former, then $uv=f|u$, this contradicts irreducibility of $u$. My question: Where in this proof have we assumed $u$ is irreducible? {I can see that we can alter this proof a bit by using UFD property to say $f=r_1...r_k$  say where $r_i$ are irreducible then the same can follow. Alternatively $uv|u$ also contradicts $v$ is not a unit. But my question is where on this proof did we assume $u$ is irreducible?} Many thanks in advance!

I am trying to understand the proof for the following theorem:     Let $R$ be an integral domain. If $x \in R$ is prime, then $x$ is irreducible.   Here is the proof:    I typed this a while ago and I don't understand the part where if $x | bc$, then $x=bc$? Is something wrong at this step?  Also, is the definition of prime elements where $p$ is prime if whenever $p|ab$, then either $p|a$ or $p|b$? Now I don't feel so sure. This could be the reason why I am not understanding the proof...


I am using Ubuntu 12.04 LTS. I have three users - one administrator and two standard users. I changed the password for administrator to 'None'. Later I used passwd command to set the password for the same user. But the password is not getting set.

I'm working on a Ubuntu system, and my client has completely forgotten his administrative password. He doesn't even remember entering one; however it is there.  I've tried the suggestions on the website, and I have been unsuccessful in deleting the password so that I can download applets required for running some files. Is there a solution?


my external hard drive has been dropped from a metere hight and when i connect to laptop It is recognized as a device and showing up in device manager but not appearing  in windows explorer.  In disk manager its showing as Disk 1 and initialize , i tried to initialize but its not working, when i connect hard disk is getting power and blue/ white light on its spinning and stopping after a minute, when i click on eject device its taking command and safely remove hardware happening and bluw color light blinking and power is off., what could be the problem for not appearing my hard drive in explorer and why its not getting initiated?

I have a 2 TB HFS+-formatted external hard drive that got dropped a couple of days ago while transferring files onto a Macbook Pro.  Now the drive's partitions won't mount.  Disk Utility can see the drive, but doesn't recognize that it has any partitions.  I've tried using  to recover files off of it, but it couldn't find anything.  In addition, our local computer repair shop said they couldn't find anything on there either.  I know that I could ship the drive off to someone like , but I was hoping for a cheaper option (since they start at about $500 for the attempt).  Is there something else I could try on my own?  Would  be able to help with something like this?


When applying for a job in academia, shall people specify in the CV if they have got visible tattoos?

I'm an undergraduate mathematics student finishing my degree.  I plan to go to grad school, and ultimately aspire to become a professor.  I really like tattoos, but I'm hesitant to get one because it could affect my future job.  Of course, if I did get one, it would be discrete and innocent.  What I really want is the axioms from ZFC wrapped around my upper arm.  I'm very interested in hearing people's thoughts on tattoos in the workplace, particularly from people who work in mathematics.  Do you think it is acceptable?  How would you judge someone based on their tattoos?  Do any of you have tattoos?  What are your experiences?


What exactly is the difference in meaning between the questions     Do you want to join us?   and     Did you want to join us?   in the context of a group of people asking asking another person who happens to be in the same place (for example, friends having dinner in a restaurant and bumping into another friend).  I would use the first variant, because to me "did" implies that the person who is asked had made up his/her mind before the question was asked.

Why isn't the present tense used?     I am wondering if you would like to come for dinner.


I was wondering if goblins were somehow just created like humans and elves, or if they were a cross-breed of some other creatures.

There are a bunch of theories about the true origin of the orcs. Tolkien tried out a few different origins for his Orcs throughout his life but died before he could fully revise The Silmarillion with his final view on their origins and nature.   There is a list of origins proposed by Tolkien():   Made of stone and slime through the sorcery of Morgoth; East Elves, where The Silmarillion contains a suggestion that Orcs are descended from East Elves captured by Melkor, their minds and bodies distorted and corrupted. Sentient beasts, another of Tolkien's theories proposes that Orcs may have begun as soulless animals of vaguely humanoid shapes, empowered by the will of the Dark Lord (Morgoth) and learning language only as parrots do. Fallen Maiar, there are hints in the History of Middle-earth series of books, (especially in Morgoth's Ring in the section "Myths Transformed"), that some Orc leaders, such as the First Age's Boldog, or the Great Goblin encountered by Bilbo and the Dwarves, may in fact have been fallen Maiar which had taken Orc form. Corrupted Men, while Tolkien at some point saw all Orcs as descended from the original corrupted and tortured Elves, later comments of his indicate, according to Christopher Tolkien in Morgoth's Ring "Myths Transformed" text X, that he began to feel uncomfortable with this theory. At about the same time he removed the references to the Thrall-Ñoldorin, he also began searching for a new origin for the Orcs. It seems Tolkien wanted to change the origin of the Orcs to make them corrupted and twisted Humans.  A mix of corrupted Elves and Men, A late idea of Tolkien seems to be that Orcs (or Orks, showing the late spelling change) had a mixed origin of Elves and Men. Some cross-bred with Men, Tolkien also suggested that Men were cross-bred with Orcs under Morgoth's lieutenant, Sauron (and possibly under Morgoth himself). The process was later repeated during the War of the Ring by Saruman. This possibly refers to the way the Uruk-hai and the Half-Orcs were created, in The Lord of the Rings.   Of all these theories, which is the most accepted, and which did Tolkien agree with the most? I always thought that orcs were made of East Elves, as explained in The Lord of The Rings, but the story goes beyond this, there are the stories in many other books that explain different things.  What can you tell me about this?


Sometimes when I work in the 3d viewport, I can't zoom in or move the view up and down at a recent point. While I'm zooming in the scene it starts a kind of slowing down and stops.  What can I do to prevent this?

I often find that I can zoom in to a point, but then cannot zoom any more, even when there is a lot of room to zoom to the meshes on the scene.   This is particularly annoying in the following scenario:  I often land up left clicking on the scene and the 3D cursor shifts there. I use Shift+C to shift the 3D cursor back to the origin. However, this also centers the view on the cursor and shifts the view to show all objects, and sometimes this zooms things way out – at this point, if I try to zoom in, I can zoom in to a point (using the pinch/zoom on trackpad), but then it stops zooming in.   How do I zoom in after that? Is there anything else I am doing wrong in this case?


I want to log traffic on website. On every hit I want to generate unique Id that will will be stored in database. To generate unique Id I wrote below code, but some time I get same entry in database.   timingVar = 'load_'+Date.now()+'_'+uniqueid();  //function used to generate unique number// function uniqueid() {     var ALPHABET = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';     var ID_LENGTH = 8;     var rtn = '';     for (var i = 0; i < ID_LENGTH; i++) {       rtn += ALPHABET.charAt(Math.floor(Math.random() * ALPHABET.length));     }     return rtn; }

I'm trying to create globally-unique identifiers in JavaScript.  I'm not sure what routines are available on all browsers, how "random" and seeded the built-in random number generator is, etc. The GUID / UUID should be at least 32 characters and should stay in the ASCII range to avoid trouble when passing them around.


I have just installed gcc 4.7 from ppa repository. Ubuntu 12.04 already comes with 4.6. When I use command:  gcc --version   It tells me it is 4.6.3 to be exact.  I have no idea of how to launch the 4.7 compiler. In fact, I wouldn't mind erasing the former version and stay with 4.7 only (I guess that wouldn't be a problem).  How can I fix this?

I want to compile my program with the latest version of gcc.  Ubuntu 14.04 comes with gcc 4.8.2, however there's 4.9.0 available, moreover, I see that it is available as a package: . I tried to install it  sudo apt-get install gcc-4.9   but it says  Reading package lists... Done Building dependency tree        Reading state information... Done Note, selecting 'gcc-4.9-base' for regex 'gcc-4.9' gcc-4.9-base is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.   Looks like it is already installed, just not as the default one? How do I utilize it to build my program?


So I have a screenshot for you, of the rear end of my female 3D model, and there in a strange indent going through it. Which only appears when I use a subdivision surface modifier.  And no, I am not talking about here butt crack xD I am talking about the horizontal line that goes all the way around.  It is unique from the possible duplicate due to the fact that it is a horizontal line, and thus is not a mirroring issue.  Here is the image:

was following a tutorial where I stumbled into this weird line in my mirrored mesh (sorry for the feet lol)      You can also download the blender file


I'm trying to add subscript/superscript in the legend text of a layout in QGIS. I can do it in a simple text box just click on View as HTML and then using for example <sub> in order to write a subscript. How could I do this in the legend text? I don't find anything to enable HTML on the legend property panel.

Is it possible to include subscript and superscript text in the title of a legend item in QGIS ?  I have tried using some text but this just appears in the title with no change to the contents.  I am looking to have layer titles such as   Annual NO2 concentration (μg/m3)  The superscript is not a big issue, as I can use the character map to get a 3, but I don't know how to get the subscript.