I know it happens due to "refraction" but it's a observation. Why doesn't light just travel from one medium to another just straight with a change in velocity?

I know that if we solve the Maxwell equation, we will end up with the phase velocity of light being related to the permeability and the permittivity of the material. But this is not what I'm interested in - I want to go deeper than that. We know that the real speed of light is actually not changing, the decrease in speed is just apparent. Material is mostly empty, the light will still travel with $c$ in the spacing. The rare atoms will disturb the light in some way. So I am interested in how the atoms affect the light. Photon absorption-emission theory Some textbooks that I read explain it in a way kind of like this: In a material the photons are absorbed by atom and then re-emitted a short time later, then they travel a short distance to the next atom and get absorbed&emitted again and so on. How quickly the atoms in a material can absorb and re-emit the photon and how dense the atoms decides the apparent speed of light in that material. So the light appears slower because it has a smaller “drift speed”. Interference theory But recently I realize an alternative explanation: Atoms respond to the light by radiating electromagnetic wave. This “new light” interferes with the “old light” in some way that results in delayed light (advanced in phase), this can easily be shown by using simple phasor diagram. Consequently effectively the light covers a smaller phase each second, which gives the impression of a lower phase velocity. However the group velocity is changing in a complicated way. I think that the first explanation does not explain the change in phase velocity of light. if we consider light travelling into a slab of negative refractive index non-dispersive material, let’s say the light is directed perpendicular to the slab. The phase velocity’s direction will be flipped, but group velocity’s direction in the material will not change. Only the second explanation can explain the flipped phase velocity direction. I guess that the velocity that we get in the first explanation is actually belongs to the group velocity. It makes sense to me that the front most of the photon stream determines the first information that the light delivers. So the question is What really cause the phase velocity of light to be decreased?  "drift velocity" of photons (they aren't the same photons, they are re-emitted all the time) phase difference between absorbed and emitted light something else  And also, I still don't really understand detailed explanation of the absorption-emission process for small light's wavelength (for large lambda compare to the atoms spacing, the photons will be absorbed by the phonons). The dispersion relation that we know is continuous and also some material is non-dispersive, therefore the absorption process must occur in all frequency for a certain range. So definitely it doesn't involve the atomic transition, otherwise it will be quantized. My guess is that the relevant absorption process gets smooth out by the dipole moment. What makes the spectrum continuous? EDIT: link for dispersion relation:


If $N$ is a $n$-bit number, how many bits longs is $N!$, approximately in $\Theta( )$ form?  I know that  $$ \log(N!) = \log(N*(N-1)*...*2*1) \leq \log (N)+\log (N-1)+...+\log(2)+\log(1) $$ $$ \log(N!) = O(N\log(N)) $$ I'm unsure about how to show it in terms of $\Theta$ instead of O notation

I'm interested in the exact barrier of $$\ln(n!)= \Theta(n\ln(n))$$  and if it even exists.  This means, there is a $c_1, c_2$ , so that $$\ln(n!) \le  \Theta(n\ln(n) c_1$$  $$\ln(n!) \ge  \Theta(n\ln(n) c_2$$  or  $$0 \le \lim\limits_{n \to \infty}\frac{\ln(n!)}{n\ln(n)} \ge \infty$$  I could use de l'Hospital for the limit fraction, since it's $\frac{\infty}{\infty}$ but the derivate of $\ln(n!)$ causes problems. Also I don't know how I could prove the two statements above or how to prove them wrong. Any help is appreciated.


*Note: I'm trying to implement "Multi-Select Picklist" in design source for configuring lightning component, Not a Picklist in design source for configuring lightning component. For reference I followed this:   I'm able to create Multi-select picklist with .design class in lightning component with design:attribute, see below screenshots for reference. But when I'm passing datasource for that Multi-select picklist then I'm getting below error.  Error I got is: Failed to save MyComponent.design: Only String attributes may have a datasource in the design file.: Source  here it is multi-select picklist in design source    when I click on that select button, I'm getting Multi-select popup as well like below,     But when I'm pass datasource then I'm getting that below error.  My code is: MyComponent.cmp  <aura:component implements="force:appHostable,flexipage:availableForAllPageTypes">      <aura:attribute name="MyVelues" type="String[]" /> </aura:component>   MyComponent.design  <design:component label="MyComponent">       <design:attribute name="MyVelues" datasource="value1,value2,value3" default="value1" /> </design:component>   the error message is here

I am populate a pick list value from design resource.But it is not loading value in the picklist. component:  <aura:attribute name="Recordtype" type="String" access="global"/> <aura:handler name="init" value="{!this}" action="{!c.doInit}"/> <ui:Inputselect aura:id="Recordty" value="{!v.Recordt}"/><br/>   Controller js:  doInit : function(component, event, helper) {     var opts = [];             var inputsel = component.find("Recordty");             var recur = component.get("v.Recordtype");             for(var i=0;i<recur.length;i++){             opts.push({"class": "optionClass", label: recur[i], value:recur[i]});         }         inputsel.set("v.Recordt", opts);     }    Design resource:  <design:component> <design:attribute name="Recordtype" datasource="Account,Contact,Lead,Opportunity"/>  </design:component>


I'm trying to understand how the Gibbs sampling algorithm works. I've simplified it into a bivariate case to help my understanding but I'm unsure how to go from conditioning on $X^{t-1},Y^{t-1},X^t$ to $Y^{t-1},X^t$.     Lets say we want to sample from $f_{X,Y}$ but we only have access to $f_{X|Y}$ and $f_{Y|X}$.  We construct a transition kernel that generates samples from our joint distribution;  $\begin{align*} K((x^{t-1},y^{t-1}),(x^t,y^t))= f_{X^t,Y^t|X^{t-1},Y^{t-1}}  &= f_{Y^t|X^{t-1},Y^{t-1},X^t}\cdot f_{X^t|X^{t-1},Y^{t-1}}\\&\ldots \\ &= f_{Y^t|Y^{t-1},X^t}\cdot f_{X^t|X^{t-1},Y^{t-1}} \end{align*}$

In an astronomical context, the authors of a paper desire to use a Gibbs algorithm. Please note: I am inexperience in MCMC algorithms, and specifically in Gibbs sampling.  What we want, in essence, is the full posterior distribution, given some data: $P(X,Y|data)$. To achieve this, we sample from the marginal distributions $P(X|Y,data)$ and $P(Y|X,data)$. In the stationary situation, sampling from these would be statistically identical to sampling from the full joint probability distribution, as I understand it.  Now, the authors note that in this particular case,   " (...) unfortunately the two marginal distributions $P(X|Y,data)$ and $P(Y|X,data)$ are in general both much narrower than the marginalized distribution $P(X|data)$: given a particular a particular $Y$ [in this case, lensing potential], $X$ [in this case, the delensed CMB] is given essentially by a delta function. This means that naive Gibbs iterations will not converge within a reasonable time."   Now these statements are completely lost on me. So my question is twofold:   The statement about the delta function is meant as explanatory supplement I think, but it doesn't clarify anything for me. Why is this 'essentially a delta function'?  Second, and more importantly: OK, suppose the conditionals are 'much narrower'. So what? Why is $P(X|data)$ even relevant, aren't we interested in $P(X|Y,data)$, $P(Y|X,data)$ and ultimately $P(X,Y|data)$ only in Gibbs sampling? Why would narrow conditions mean slow convergence?   The paper in question is a review paper by Challinor and Lewis, 2006. The arxiv print can be found here:    And the text I'm referring to is at the end of section 8, delensing the sky.


I have noticed that when Google searching for a site like "nike" a google ad shows up for their website. Most people looking for the website will understandably click on the advert as it's the first link, however this will be costing the company money which seems like a waste as the first organic link (directly underneath) is their site.   When you buy ads with Google AdWords, is there a way to stop your ad showing when people search for your site or brand name?  Is it just the default behavior that the ads always show for brand searches?

I recently identified 2 companies who are actively targeting ads through Google AdWords using our trademark (registered in the UK). I filed a complaint with Google, although they are not willing to remove these ads.     Please note that we will not be able to process this complaint for   your trademark * because you requested that we remove all   ads that are currently using your trademark as a keyword.       We do not investigate keyword complaints for trademarks, as described   at .   As a result, we won't be able to remove ads that are using your   trademark as a keyword.   If Google allow other competitive firms to leverage traffic through AdWords off the back of an established brand where does that leave us? Must we also use AdWords to outbid our competitors on our own company name?   I'd be interested to know of anyone who has experienced something similar. If Google won't do anything to police this then is litigation the only option available?  EDIT  It seems Google have recently changed their policy on this and are no longer arbitrating trademark disputes when used in keywords, only in ad copy. This can't be good for search quality!!?


I had some personal info shown on my profile, and I removed it.  I'm just curious: Does a record of profile revisions, much like post revision history, exist?  If so, who can access it? Mods? Devs? Anonymous users :p?

I would like to have a history of the "About me" box in my profile.  I edited my details on my profile page and it replaced all profiles with the same content, so I'd like to be able to go back to the old information.  Having a complete history of all information would be of use to moderators.


I am fairly new to the python. I am using this Seaborn module for instance and I wanted to know is there any way I could know what are all the functions included as part of this module (such as scatterplot, regularplot or any other things which could be used using this module).   I tried using pip list and it gave me seaborn version as 0.10.0. When I am trying the use scatter plot , I am getting error as  "module 'seaborn' has no attribute 'scatterplot'" I tried searching over the internet, but was not able to get any clarity as it was saying some versioning issues. But I wanted to check what are the functions included as part of this module.   Below is the code:   import seaborn as sns  sns.scatterplot(x="A", y="B", data= abc)   Can anyone please help if there is any way to know the functions of a module?

I have a Python module installed on my system and I'd like to be able to see what functions/classes/methods are available in it. I want to call the help function on each one. In Ruby I can do something like ClassName.methods to get a list of all the methods available on that class. Is there something similar in Python? eg. something like: from somemodule import foo print(foo.methods)  # or whatever is the correct method to call


After doing a good amount of research, it's become fairly obvious that I ought to be using the extended Euclidean algorithm to calculate d from the data that I already have.  However, this isn't an area of mathematics I'm very familiar with, and the algorithm both takes and outputs multiple integers instead of just one.   So, my question is: Which of the numbers that I already have to I need to input into the algorithm, and of the several numbers it outputs, which is the one I'm looking for?

When given $p = 5, q = 11, N = 55$ and $e = 17$, I'm trying to compute the RSA private key $d$.  I can calculate $\varphi(N) = 40$, but my lecturer then says to use the extended Euclidean algorithm to compute $d$. That's where I get stuck.    Here's my work so far:  First I use the Euclid algorithm to calculate:  40 = 2(17) + 6  17 = 2(6) + 5 6 = 1(5) + 1 = gcd   So I know the GCD is 1. Applying the 'extended' section of the algorithm:  6 = 40-2(17) 5 = 17-2(6) 1 = 6-1(5) 1 = 6-1(17-2(6)) 3(6) = 1 (17) 3(40 - 2(17)) - 1(17) 3(40) - 3(17)   I know the answer is $33$, but I have no idea how to get there using the extended Euclidean algorithm. I can't figure out why I'm getting $3(40) - 3(17)$ when I know the answer should contain $33$.


I have an android phone and normally use the Google Messages app for sending and receiving SMS. Yesterday, I used the macOS Messages.app app for the first time to send a friend a link.  I guess they have an iPhone, because now when they text me it comes to Messages.app instead of to my phone.  I'm assuming this will be the same for all other iOS users. How do I prevent all Messages.app and iOS Messages users from sending me NON-SMS messages?  Thinks I have tried:  Closing Messages.app.  I still get macOS notifications of messages. In Messages > Preferences… > Accounts > [my email address], untick "Enable this account".  Then my friends messages disappear and I never see them at all, at least until I reenable in Messages.app. Looking in System Preferences and on icloud.com and appleid.apple.com to see if there is some setting I can disable—but I've not found anything relevant. Using  to unregister my mobile number.  When I attempted this it gave me the message "Your phone number is not registered with iMessage."  This question was closed as a duplicate of , but as noted my phone number is not registered with iMessage, so that question is not relevant. Am I doomed to never receive SMS from iPhone users ever again?

I have always used an Android phone, but text messages from certain friends get hijacked by iMessage. How do I prevent iPhones and MacOS Messages from sending me iMessages? I need all messages to be SMS or MMS. Some friends with iPhones will text me, but I don't receive the message. Today I noticed the Message app on my Mac had notifications. I never open this app since I don't use iMessage, but I looked today, and found multiple "lost" messages from several weeks ago. Please note that this is NOT the same question as . My Android phone is not, and has never been, registered with iMessage, and I have already followed those instructions. Another poster () had the same question as me----but it was closed, being deemed as the same as the Removing phone number question. It's actually fairly different. I have tried:  Leaving my Messages app closed on my Mac. But somehow messages from these people get hijacked. Deregistering my mobile number using Apple's online Deregister iMessage tool. When I attempted this, I got the message "Your phone number is not registered with iMessage." Finding a setting on my Android phone that addresses this. The problem is apparently (and logically seems to be) on the Apple end.  Things  says he tried:   Closing Messages.app. I still get macOS notifications of messages. In Messages > Preferences… > Accounts > [my email address], untick "Enable this account". Then my friends messages disappear and I never see them at all, at least until I reenable in Messages.app. Looking in System Preferences and on icloud.com and appleid.apple.com    to see if there is some setting I can disable—but I've not found    anything relevant. Using Apple's Deregister iMessage tool to unregister my mobile    number. When I attempted this it gave me the message "Your phone number is not registered with iMessage."


I wish to set a grub password! I dont know how! Please tell me how to make a grub password! Ver: Grub: 2 Ubuntu: 20.04 Desktop: Gnome

How to password protect Grub menu from the ro recovery nomodeset command. I want it to where no one unless you have the password to make changes to the menu to try to get into recovery.grub


In one dimensional motion the general potential is given as in the figure above  When energy is between V min and V 1 the energy levels are discrete like in the potential barrier and well example or when the system is bounded like in the infinite square well potential.  Why is this so? Why they are not continuous.  The solution of these problems by applying boundary conditions give discrete energy level but I can't figure out why?

Given some potential $V$, we have the eigenvalue problem   $$ -\frac{\hbar^2}{2m}\Delta \psi + V\psi = E\psi $$   with the boundary condition   $$ \lim_{|x|\rightarrow \infty} \psi(x) = 0 $$   If we wish to seek solutions for   $$ E < \lim_{|x|\rightarrow \infty}V(x), $$   I find textbooks like Sakurai and others assert that (without proof) set of all such eigenvalues $E$ that admits nontivial solutions is discrete, which gives us liberty to index them with natural numbers (principal quantum numbers). Can anyone help me with a little elaboration of this mathematical fact ? As a student of mathematics, I know that compact operators have discrete spectrums, so for the operator $ T : L^2 \rightarrow L^2 $given as  $$ T(\psi) = -\frac{\hbar^2}{2m}\Delta \psi + V\psi. $$   Are there methods to show that $T$ is compact? Or possibly other ways to establish discreteness of its eigenspectrum?


Is there a way to tell the Windows Run Dialog (Win-R) to start programs in a folder other than C:\Users\<username>\?

My new Windows XP work computer's command prompt automatically brings up "H:\>" when I open it.  Is there a way for me to change that safely?  Specifically, to "C:\foo\bar\Something Else"?  I found the method of changing the Autorun value through Google, but it came with a warning that it "might affect the functionality of batch scripts."  Bonus note: I was originally getting at this issue in , but I didn't ask very directly.  The answer I ended up accepting was really good, so I wanted to leave it there.


I need to know how to find the reflector H of Householder such that if $v= \begin{pmatrix} 3\\ 4\\ 12 \end{pmatrix}$ then $Hv=\begin{pmatrix} 0\\ 0\\ 13 \end{pmatrix}$  I've been reading a bit about it, but usually they focus on removing all the components except the first one, but it's not my case. Could someone help me solve this and give me a simple way to understand this?  Thanks!  Edit:  Let me tell you what I have:  my Householder vector u is $\begin{pmatrix} 3 \\ 4 \\ 12\end{pmatrix} - \begin{pmatrix} 0 \\ 0 \\ 13\end{pmatrix} = \begin{pmatrix} 3 \\ 4 \\ -1\end{pmatrix}$  , then, I use it to build $$H=I-2\frac{u \times u^T}{u^Tu}$$ , but at the end, when I multiply $𝐻𝑣$, I don't get what I want. What am I doing wrong?

I have a tutorial problem to start with vector $$\begin{bmatrix}12\\5\\12\end{bmatrix}$$ and design a Householder transformation which annihilates the third component but leaves the first unchanged $$\begin{bmatrix}12\\?\\0\end{bmatrix}$$  I have looked at a few other answers but none quite seem to help me.  : This is pretty much the same question just different numbers. I get lost with the jargon in the accepted answer.  : This answer is on the same theme of what I am asking but the accepted answer is too vague for me.  I have these formulae: $\bf{v}=\bf{x} + sign(x_k)\lVert x\rVert \bf{e}_k$; $H=I-\frac{\bf{vv^T}}{\bf{v^Tv}}$  I have had many false starts on this that have led nowhere. Any ideas on where to start?


Let $f_n$ be the Fibonacci sequence, $f_1=1$, $f_2=2$.       Prove that each positive integer admits a unique representation in a form $a_1f_1+a_2f_2+\cdots+a_nf_n+\cdots$ such that      1) each $a_i$ is either $0$ or $1$;        2) there are finitely many numbers $a_i$ equal to $1$;          3) no two consecutive numbers are equal to $1$.   Attempt:  Since every Fibonacci number can be represented as $1$ times itself, obviously satisfying above three properties, we only need to show integers between every two consecutive Fibonacci numbers satisfy three properties.  Since the gap between two consecutive Fibonacci numbers $F(n)$ and $F(n+1)$ is equal to $F(n-1)$, we only need to show that integers from $1$ to $(F(n-1)-1)$ can be represented in the required form, since we can add them to $F(n)$ to get every integer in the gap between $F(n)$ and $F(n+1)$.  I try to use induction.  The first Fibonacci number subtracted by $1$ that is not another Fibonacci number is $F(4)$, since $F(4)-1=4$, $1$ to $4$ obviously satisfy three properties.  Suppose $1$ to $F(n)-1$ can be represented in the form satisfying three properties, we prove $1$ to $F(n+1)-1$ can also do that.  However I found it hard to continue, maybe this is not a good idea in the first place. Is there a better way to do this problem? Another question is that I don't understand what the point of the second property is. Since there are only finitely many Fibonacci numbers that are less than a integer, how could it possible to represent it as a combination of them with infinitely many coefficients that is equal to $1$?

Proof that every natural number $n\in \mathbb N$, can be written as the sum of different Fibonacci numbers between $F_2,F_3,\ldots,F_k,\ldots$.  For example: $32 = 21 + 8+3 = F_8+F_6+F_4$  Research effort:  The base step it's simple:  Let $k=1$ it can be britten as $k=1=F_2$  For the inductive step I considered:  Let $k = k  F_2 =F_2+F_2+\cdots+F_2 = \sum_{i=2}^w a_iF_i, a_i =\{0,1\} $  Then if $k$ suffice I want to see if $k+1$ suffices too... But I'm not realy seeing how to use the inductive hypothesis, so I assume It's wrong.  Any thoughts on which can the inductive step be?


Is the closure of the unit ball of $C^1[0,1]$ in $C[0,1]$ compact?  For this let us take a sequence $x_n$ in $C^1[0,1]$ to show it has a convergent subseqence  How to proceed with this.I am not so sure whether  it is the way to ask a question here

[I really want to apologize if this problem looks a little too long.]  The problem :  This is taken from  and it says...     Prove or disprove the comapctness of the closure of the unit ball of $C^1[0, 1]$ in $C[0, 1]$.   What have I tried?  I think it's pretty clear that the unit ball in $C^1[0,1]$ is $B= \{f \in C^{1}[0,1]: \lVert f \rVert \leq 1\}$. Let us denote $K= \operatorname{cl}_{C[0,1]}(B)$, the closure of $B$ in $C[0,1]$.  I really didn't have much clue how to start working on this problem but finally thought about using the sequential approach. If $a$ and $b$ are two points such that $0<a<b<1$ then I think there can be functions $f_a$ and $f_b$ having the property that $\lVert f_a-f_b \rVert = 1$ which are sufficiently smooth to be in $C^1$.  Now as it is quite tedious to construct these functions explicitly, I scanned a hand-drawn picture of what I think they might look like.     Here $f_a$ and $f_b$ take zero values in almost all of the interval $[0,1]$ and jumps up at $a$ and $b$ respectively. Also, as is clear from the figure, they don't assume non-zero values simultaneously. Now, my argument is clear: however close the two points $a$ and $b$ come to each other (remaining distinct) there will always be functions like $f_a$ and $f_b$. They may get steeper and steeper but will never lose their $C^1$-ness.   So if I consider the sequence $(\frac{1}{n})$ in $[0,1]$, I will get a sequence $(f_{\frac{1}{n}})$ in $B (\subseteq K)$ where for $m \neq n$ we will have $\lVert f_{\frac{1}{m}} - f_{\frac{1}{n}}\rVert = 1$. Hence the sequence $(f_{\frac{1}{n}})$ cannot have a convergent subsequence, thereby proving that $K$ is not sequentally compact and hence not compact.  But I'm not very sure about all these. A friend of mine told me that this same problem has a positive answer and that made me sufficiently confused.  So, here comes my question...     In the above argument, where have I gone wrong?   What is the real answer? And how to prove it?   Thanks a million for reading my extra-long question. And thanks a zillion for any help that you can offer.


I have a class, which contains a wrapped parametrized array:  public class CatContainer <T> {      T[] names;      public CatContainer(){         names=(T[]) new Object[10];     }      void set(int index, T value){         names[index]=value;     }  }   And have corresponding client, where i'm using two ways to access the array.  CatContainer<String> cats=new CatContainer<>(); //cats.names[0]="Murzik"; //cats.set(0, "Murzik");   Can you explain me, why when i'm using a setter the programm works fine, but when i'm using the direct access cats.names[0]="Murzik" the programm throws the Exception?     java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to   [Ljava.lang.String;   P.S. i have a solution about creating the generic array - the way with setter works fine. i'm searching for the explanation about the specified exception. i have no idea why it has been thrown when i'm using the direct access to the array. I know that generics in java have no specified type at run time and all parameters casts to Object type. But string is a subtype of object, so why the code is not working as expected?

Due to the implementation of Java generics, you can't have code like this:   public class GenSet<E> {     private E a[];      public GenSet() {         a = new E[INITIAL_ARRAY_LENGTH]; // error: generic array creation     } }   How can I implement this while maintaining type safety?  I saw a solution on the Java forums that goes like this:  import java.lang.reflect.Array;  class Stack<T> {     public Stack(Class<T> clazz, int capacity) {         array = (T[])Array.newInstance(clazz, capacity);     }      private final T[] array; }   But I really don't get what's going on.


A murdering thief or a thieving murderer.   I have looked up all possible literary devices, and can't seem to find one...

There are many sayings that invert the word order to convey a different meaning.  e.g.   "Do you live to work or do you work to live?" "He who fails to plan, plans to fail"   Is there a name for this type of saying?


I have edited this question with its title. Virtual particles, as I understand, arise as intermediaries in the calculations describing interactions such as scattering between real particles and in drawing certain Feynman diagrams.   My question is not whether virtual particles have real physical existence by direct observation. My question is, whether the mathematical language of "virtual particle-antiparticle popping in and out of existence", is even mathematically meaningful whenever you take everything (all real quanta) out of space. By empty space, I understand, the vacuum of a free or an interacting quantum field theory. May be  roughly explains my question. Can the vacuum loops be given such a meaning?  Edit-The maximum voted answer in  talks about virtual particles in real scattering experiments. But it does not address whether this virtual particles have any mathematical meaning, when there are no real quanta or particles present in the picture.

I have heard  pop in and out of existence all the time, most notable being the pairs that pop out beside black holes and while one gets pulled away. But wouldn't this actually violate the conservation of energy?


In the past, Jeff always read bounty questions on meta so offering a bounty was the best way to make sure that someone from Stack Exchange replied to your question.  Now he's gone, is this still the case? If not, could someone else volunteer to start doing this? I ask because it seems a useful way to attract your attention and  (though I'm sure there are other examples). Thanks!

So, I've noticed that in some instances, a heavily desired feature or description of an implementation will, here in meta.stackoverflow, be awarded bounties.  Presumably, the desire is to communicate to the Stack Overflow development team (and/or the community managers who lobby on our behalf) the importance of said feature to the users' well-being and happiness.  My question is simple: Does it work?  And by "work" I mean, does it actually change the prioritization of a feature request.  I am not interested in the "rightness" or "wrongness" of the practice.  I am curious about its effectiveness.  From a process perspective, is there any feedback mechanism that alerts devs to bounties awarded on feature requests.  Obviously, there is overlap between the readers of this site and the devs.  But:   Are the developers actually influenced by the bounties?   Is there any correlation between a bounty and the attention which those features are given?   Are developers even notified when a bounty is awarded on a feature request, or are the devs just responsible for checking it when they get around to it?   NOTE: This differs from  in that I am asking (a) if it is effective an (b) if there is a formal process in place for it.


How do the Fat Lady, Dumbledore, and Phineas create portraits that can talk? And if it's easy, why don't all wizarding people make talking portraits of themselves? Do you need an audio snippet from a person?

Does J.K. Rowling address how the interactive portraits work? Would a portrait painted after a Wizard/Witch died become interactive, or does the painting of the portrait have to take place during the Wizard/Witches lifetime?


Yes I have seen the explanation of why this is so in quantum mechanical textbooks. However, let's use the identity operator and do the following:  $$\langle x|x'\rangle =\langle x|I|x'\rangle =\int\langle x|x''\rangle\langle x''|x\rangle dx''=\int\delta(x-x'')*\delta(x''-x)dx'\tag{1}$$  (the integral is from $-\infty$ to $+\infty$. Now, let's look at what we have inside the integral. Clearly, the term inside  $$\delta(x-x'')*\delta(x''-x)\tag{2}$$  is nonzero only if $x''=x'=x$. We can restate this as follows:  $$\delta(x-x'')*\delta(x''-x)=0\text{, if  } x\neq x'\tag{3}$$  and  $$\delta(x'-x'')*\delta(x''-x)=\infty \text{ (for certain $x''$ in the region from $-\infty$ to $+\infty$)}\tag{4}$$  if $x=x'$; this means that  $$\delta(x-x'')*\delta(x''-x)=\delta(x'-x).\tag{5}$$  However, if we put $\delta(x'-x)$ instead of $\delta(x-x'')*\delta(x''-x)$ we get the following:  $$\int\delta(x-x'')*\delta(x''-x)dx''=\int\delta(x'-x)dx''=\delta(x'-x)\int dx''\tag{6}$$  (I remind that the integral is from $-\infty$ to $+\infty$). So I get that  $$\langle x|x'\rangle=\delta(x'-x)\int dx''\tag{7}$$  which is not just $\delta(x'-x)$. I would be grateful if someone could tell me where my assumptions are wrong and why.

I've tried to find any solution or proof for $$\langle x| x' \rangle=\delta(x-x'),$$ but I only came to this post:   So I got the information, that the vector $|x\rangle$ form a dirac-normalized basis for the Hilbert Space.   I know that the dirac-delta distribution is defined like this: $$\delta(x-x') = \begin{cases} 0 &\mbox{if } x\neq x' \\ \infty & \mbox{if } x=x' \end{cases},$$ this means that my x' is a point on my x axis where I have my infinite high peak. And also $$\int_{-\infty}^{\infty}dx\cdot \delta(x-x')=1.$$  But how actually correlate this with the scalar product of vectors x, x' in the Hilbert Space that form a so-called 'diracl-normailzed" basis of it?  Can you give me some tips on this please? Or maybe you actually know a link, where this is explained.


I'm just wondering why the n choose k formula  $n \choose k$ = $\frac{n!}{k!(n-k)!}$  always gets you a whole number. I know that obviously there can only be a whole number of "ways" to choose k items in n items, but I'm more interested on how the factorials divide.

From its definition a combination $\binom{n}{k}$, is the number of distinct subsets of size $k$ from a set of $n$ elements.  This is clearly an integer, however I was curious as to why the expression  $$\frac{n!}{k!(n-k)!}$$ always evaluates to an integer.  So far I figured:  $n!$, is clearly divisible by $k!$, and $(n-k)!$, individually, but I could not seem to make the jump to proof that that $n!$ is divisible by their product.


My phone was stolen, I'm trying to login to Gmail, but since Gmail sends a code when you log in I can't get the code. I still know my password but it still asks for the code.  I tried my recovery mail but it says:     There's no Google account with the info that you provided.   But I provided the right info. Is it still possible to retrieve my account?

I have forgotten the password or username for my Google account, or I'm unable to access my account for other reasons.  How can I recover my account?  (This Q&A is meant as a general description for all Google and Gmail username/password questions. See: )


Changing my Gateway MX6448 laptop out from Windows XP  Downloaded Ubuntu 13.10.   Cannot find a way to get my wireless network be detected.  I have Broadcom BCM4311 wireless but cannot find any settings for it in the operating system. The wireless router that I am using is a Netgear n300 model # WNR2000.   I am also using a MacBook Pro and Mac Pro within the network. What can I do?

I'm having serious problems installing the Broadcom drivers for Ubuntu. It worked perfectly on my previous version, but now, it is impossible.   What are the steps to install Broadcom wireless drivers for a BCM43xx card?  I'm a user with no advance knowledge in Linux, so I would need clear explanations on how to make, compile, etc.    lspci -vnn | grep Network showed:   Broadcom Corporation BCM4322 802.11a/b/g/n Wireless LAN Controller [14e4:432b]      iwconfig showed:  lo        no wireless extensions. eth0      no wireless extensions.   NOTE: Answer below is updated every time new information is added and confirmed working.


Recently I bought a reversal ring for my Canon 700D, to take macro photography. I reversed an 18-55mm kit lens. When I tried to take photos, the aperture went to f00. What can I do to set the aperture?

Is there anyone using reverse ring and know how to lock the aperture.   I tried doing the techniques provided on youtube. First connecting the lens on original positions then lock the aperture by pressing the AE lock button on the camera. after that reverse the lens.  But this method is not locking the aperture.  Help if anyone know how to lock in reverse.  Thanks.


Is it possible to create bootable USB disk which would be UPDATED in the very same way as HDD disk does? I.e. when I modify a file in the booted USB, the USB will remember all the changes afterwards in next boots with it? OR when I install new packages, the USB will be updated accordingly for ever?  The answers there are much too complex for me.  HOW at least it is called in the slang that isntalation that allows these possibilities of updating USB: full/persistent?  MOREOVER I'm running win 8.1 on my PC. How do I install that updatable USB in this case??

If you are hurrying to reply, System → Administration → StartUp Disk Creator -- no, that's not what I'm talking about.   I want to try Ubuntu 11.04's Unity without touching my existing Ubuntu install.  To do this, I need to install the nVidia drivers first (sigh).  To do this, I need changes to persist a reboot.  To do this, I need to really install Ubuntu on a USB key.  How do you do that?    What I tried   I tried to make a USB key from , then boot from it, then choose "Install Ubuntu." The installer refused to install to the installation media itself. I tried, from my installed copy of Ubuntu:  sudo kvm /dev/sdb --cdrom .cache/testdrive/iso/ubuntu_natty-desktop-i386.iso   ...but the installer didn't detect the disk properly.


I have files on my MacBookPro that I copy into Synology. I have noticed that Finder and FileStation show different file size.  I have attached a screenshot for both these. Finder on MacBookPro.   And on FileStation on Synology.   Why is this happening?Is there some config setting that I can change on either of the systems that will show the same size on both?

I was taking a look at a HDD and I found a document (from Toshiba, link: ) that says:  "One Gigabyte (1GB) means 10^9 = 1,000,000,000 bytes using powers of 10. A computer operating system, however, reports storage capacity using powers of 2 for the definition of 1GB = 2 ^30 = 1,073,741,824 bytes, and therefore shows less storage capacity."  Then powers of 10 are bigger than powers of 2, OK.   Example 10^2 = 100 and 2^2 = 4.   But I do not understand the document which says for the same storage capacity:  1GB is 1,000,000,000 bytes (powers of 10) and 1,073,741,824 bytes (powers of 2), then: it shows less storage capacity (the powers of 2). Why is it less? If I see for 1GB more storage capacity in powers of 2 than powers of 10.


Hello  have dual boot my laptop Running Kali linux 1.0.7 and Ubuntu 14.04. For some Application i need windows,As wine does not support that apps and not have sufficient RAM to run windows in virtual machine, my Question: i have ubuntu's grub loaded in my laptop, so when i delete kali linux partition and made un-allocated space , can i install windows 7 in that un-allocated space? if yes after installing windows 7 should i need to re-install grub (i don't think so because i have ubuntu's boot loader) and install kali after installing windows 7

I have Ubuntu on my laptop. Now I want install Windows 7 in a dual-boot. How can I do this? I can't lose my Ubuntu files, and I'm afraid that I might break . Go  for UEFI only!


In Minecraft I have a Blast Protection 4 on a diamond chest plate and another diamond chest plate with Protection 3. Which one is better? By the way this armor is going to be used Battling the Wither, the Ender dragon, and the Elder guardian.

Prior to 1.4.6 it was a well known fact that the protection enchantment on armor was strictly superior to the other enchantments and that simply having a few pieces with protection III/IV would max out this protection, leading to the best possible set of armor.  Now that this has , however, I'm curious to see if anyone has analysed what the optimal armor configurations now are?  Presumably it will be some combination of protection enchantments and other enchantments, going by the description of how enchantments work now on the wiki.  Or, are we forced to choose one or more types of protection to max out?  (This would be the case if there are not enough total enchantments possible to max out all areas).  If this is the case, it would be great to see some analysis of how to optimise that choice as well.  I've looked around but haven't found any good mathcrafting on this question yet.  Furthermore, beyond protection against taking damage, can someone include some explanation of the hidden utility bonuses?  For instance, Blast Protection has been described in wiki sources as reducing the knockback effects from explosions, and Fire Protection is described as reducing burn time.  Do these effects scale and max out at some enchantment level, and does Projectile Protection similarly reduce the knockback effect from projectiles?


I have been dealing with this issue since i bought this phone ( Galaxy Note 4 ). I need to change my play store to the US, but I couldn't. I have tried many methods especially, changing my home adress of (google payment or wallet). Many people used to download an app called (Hola and others) ,but i don't prefer to use apps in this way. In google play (Contact us) mentioned that I need to put a payment method related to US. Anyway, I don't have a payment for US.   Is there any way to do it?

Can someone tell me how to change the country preference for Google Play? I have searched high and low but in most of the forums people ask you to go to Gmail settings -> edit profile and change the country there. But there is no place to change the country in settings! There is a something called place (which can be marked as current) but that has no impact on Google Play.  I don't want to circumvent country restrictions, I want to permanently change the country. So it's NOT a duplicate of .


Let $ S_n $=$\int_0^1 \frac{nx^{n-1}}{1+x}dx $ for n$ \ge $1 then as n tends to infinity sequence tends to:  1.0 2.1 3. 1/2 4. Infinity  Is there any other way, than to first do integration, and then take limit?

Let $s_n$ be a sequence defined as given below for $n \geq 1$. Then find out $\lim\limits_{n \to \infty} s_n$.   \begin{align}   s_n = \int\limits_0^1 \frac{nx^{n-1}}{1+x} dx  \end{align}  I have written a solution of my own, but I would like to know it is completely correct, and also I would like if people post more alternative solutions.


I've added my site to Google Webmaster tools kanosa.com. The site was submitted a few months ago. The index status shows 0 but it shows multiple URLs have been indexed in the sitemaps section. If I search in google I can see that the site is indexed and several pages appear:

Statistics show all entries of my wordpress blog have been tracked, but none have been indexed.  I thought it would be just a matter of indexing delay, but it has been 3 weeks already, and I can find the entries on google when I query the entry name, (e.g "relaxacion.com musica para dormir bebes" shows at the bottom of search results first page)  Is there any problem with my wordpress setup?


I am trying to clip a vector shapefile- points according to a DEM in QGIS. I used GDAL function and polygonized the DEM. Then I ran the Vector-Geoprocessing tools-clip in order to crop the vector data points. The whole QGIS crashed couple of times while doing this and I have never achieved any results. Could you please suggest any alternative steps for me? Many thanks!

I am using QGIS 2.2  I have one vector line layer (roads) that stretches beyond my base image (see below).      I wish to have the roads "clipped/trimmed or deleted" right at the edge of the image's extent (see below):    How can I achieve this?


Here is the context:     Culinary cultural fusion is all the rage; more novels translated from languages then ever before, although few are read, and in the surest sign of cultural globalization, football, the world's game, finally has reached America.   Actually I cannot get the grammar of the phrase. Why did the speaker use the preposition in with it? Wouldn't it make sense without it? If it would not, then could you please explain what the difference is with in and without?

It is from . It is at around 8 minute and 39 second. Here it goes:     Culinary cultural fusion is all the rage; more novels translated from languages then ever before, although few are read, and in the surest sign of cultural globalization, football, the world's game, finally has reached America.   I guess the sentence would make sense if the preposition in were dropped out. Could you please tell me what did the host use it for?


Apologies if this has been asked before, nothing turned up when I tried to search.  I'm noticing some very interesting behavior when I try to do PCA on pairs of some dummy datasets I just invented, which are permutations of a fixed set (here just the range from 1 to 10.) In R:  x <- c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10) y <- c(10, 2, 1, 5, 4, 3, 9, 8, 7, 6) z <- c(8, 3, 2, 1, 4, 7, 9, 6, 5, 10)  df1 <- data.frame(x, y) df2 <- data.frame(x, z) df3 <- data.frame(y, z)   I then use prcomp:  > prcomp(df1) Standard deviations (1, .., p=2): [1] 3.415650 2.581989  Rotation (n x k) = (2 x 2):         PC1        PC2 x 0.7071068 -0.7071068 y 0.7071068  0.7071068 > prcomp(df2) Standard deviations (1, .., p=2): [1] 3.681787 2.185813  Rotation (n x k) = (2 x 2):         PC1        PC2 x 0.7071068 -0.7071068 z 0.7071068  0.7071068 > prcomp(df3) Standard deviations (1, .., p=2): [1] 3.858612 1.855921  Rotation (n x k) = (2 x 2):          PC1        PC2 y -0.7071068 -0.7071068 z -0.7071068  0.7071068   So, each component of each principal component is either $\frac{\sqrt{2}}{2}$ or $-\frac{\sqrt{2}}{2}$. I'm not sure exactly why this would be, although it makes a certain kind of sense: both variables 'contain the same data' in a sense, and if we didn't see this behavior, we would be 'preferring' one variable over the other.  That's a very high-level and handwavey view of things, though. Also, if I try more than two variables at a time, this behavior disappears:  >prcomp(data.frame(x, y, z)) Standard deviations (1, .., p=3): [1] 4.208109 2.603247 1.736355  Rotation (n x k) = (3 x 3):         PC1        PC2        PC3 x 0.5003708  0.8107791 -0.3037538 y 0.5781928 -0.5740476 -0.5797951 z 0.6444549 -0.1144843  0.7560233   Can someone give me some insight into what's going on here?

I perform Principal Component Analysis using two variables that are standardized. This is done by applying a SVD on the correlation matrix of the concerned variates. However, the SVD gives me the same eigenvector (weights) irrespective of what the two variables are. It's always [.70710678, .70710678]. I find this strange. Of course, the eigenvalues differ.  My question is: How to interpret this?    PS. I wanted to conduct a total least squares regression on two variables. My statistical programme does not provide TLS, but TLS luckily equals Principal Component Analysis, as far as I know. Hence my question. The question is not about TLS directly, but why I get the same eigenvectors irrespective of which variables I use (as long as they are exactly 2).


Is there any relation connecting between the effective refractive index $N$ and the refractive index $n$ in waveguide?

Can some one please explain in simple words that what is ?  How it is different from the ?  And how we can calculate the effective refractive index?


I have a dictionary  Example: dict = {'one':1 ,'two':2 , 'three':3}   I want to use/have two values within single iteration of for loop.  End result should be like this  # 1 2 (First iteration) # 1 3 (Second iteration)  # 2 1 # 2 3  # 3 1  # 3 2    Can someone please tell how I can achieve this in python dictionary.   for i in dict.values():    # how do i Access two values in single iteration and to have result like mentioned       above   Thanks

How do you generate all the permutations of a list in Python, independently of the type of elements in that list?  For example:  permutations([]) []  permutations([1]) [1]  permutations([1, 2]) [1, 2] [2, 1]  permutations([1, 2, 3]) [1, 2, 3] [1, 3, 2] [2, 1, 3] [2, 3, 1] [3, 1, 2] [3, 2, 1]


I had this problem.     Let $G$ be a group and $a,b\in G$ such that $a^{-1} b^2 a=b^3$ and $b^{-1}a^2 b=a^3$. Prove that $a=b=1$.   Somehow I solved it, but it was a bit tedious (for example in some place I got to something like $b^3 =a^{-3}b^{-1}a^2a^{-3}b^{-1}a^2a^{-3}b^{-1}a^2=a^{-3}b^{-1}a^{-1}b^{-1}a^{-1}b^{-1}a^{2}$). I first proved that $b=a^{-2}ba^3$ (It's also true that $b=a^2ba^{-3}$) and then (Details not included) that $b^3=ab^6a^3$. Then (Details not included) that $b^3 a^3=a^{-1}b$, then $b^{-1}=a^4$ and from that $a^2=a^3$, from which $a=e$ (There are a lot of lines covering these details but there may be a mistake in these lines). It's the same to get $b=e$.  So, is there any shorter, or less tedious way to prove it?

Suppose $a$ and $b$ are elements of a group $G$. If $a^{-1}b^{2}a=b^{3}$ and $b^{-1}a^{2}b=a^{3}$, prove $a=e=b$.   I've been trying to prove but still inconclusive. Please prove to me.  Thanks very much for proof.


It is not isometric, neither is it pure 2D.  What is this graphics view called?

What is the actual term for the 'top-down' style of the Super Nintendo games such as Final Fantasy 6, Chrono Trigger, et cetera. I'm looking for the equivalent term of:   'isometric' - (Jaggered Alliance, Final Fantasy Tactics, Fallout),  'first person' - (Half Life, Doom, Quake),  'birds eye' - (Grand Theft Auto) ? insert term here ? - (Final Fantasy 6, Chrono Trigger)


Let $R_1,R_2$ be two rings with identity. If for some $n\in\mathbb N$, $M_n(R_1)$ and $M_n(R_2)$ are isomorphic as rings, can we deduce that $R_1\cong R_2$? I can prove it when both $R_1,R_2$ are local or commutative.

Let $R$ and $R'$ be rings (with 1 but no further assumptions) and $n \in \mathbb{N}$. Does the following implication hold?     If $M_n(R) \simeq M_n(R')$ then $R \simeq R'$.   If the rings are commutative then it follows from considering the centers of $M_n(R)$ and $M_n(R')$. If the rings are division it also holds and even stronger, it holds even if the matrices are not of the same size.  I thought about considering the embeddings of $R$ in $M_n(R)$ as diagonal matrices, but since I do not want to asume anything about the isomorphism I was not able to conclude that these subrings of matrices in $M_n(R)$ and $M_n(R')$ are isomorphic. I hope someone can help me or with a proof, an idea or a counterexample. Thank you.


Let $f: [a,b] \to \mathbb R$ be a function differentiable in  $(a,b)$ , then is it true that there is a non-constant   sequence $(x_n)$ in $(a,b)$ such that the sequence $\big(f(x_n)\big)$ is convergent ?

Continuous Functions are not Always Differentiable. But can we safely say that if a function f(x) is differentiable within range $(a,b)$ then it is continuous in the interval $[a,b]$ . If so , what is the logic behind it ?


I leave in the uk with my husband and I just had a baby.  I want my mum to come viait for 3 month. my question is; does my mother need to submit any document from her like bank statement.  she does not work she is just a petty trade just to keep busy.

The UK Visas and Immigration Directorate publishes  that provides helpful tips that can result in successful visa applications. Section 2 of this guidance opens is entitled "other documents you may want to provide" (emphasis mine).  Section 2: other documents you may want to provide – all visitors This section provides guidance on the types of documents that you may want to provide to help us consider your application against the Immigration Rules. Previous travel documents/passports, which show previous travel. Financial documents showing that you have sufficient funds available.  These must clearly show that you have access to the funds, such as:  bank statements building society book proof of earnings such as a letter from employer confirming employment details (start date of employment, salary, role, company contact details) where a third party (who is either in the UK or will be legally in the UK at the time of your visit) is providing financial support to you e.g. a business, a friend or a relative, documents to show that they have sufficient resources to support you in addition to themselves and any dependant family should be provided   The first item is "bank statements" and this ties in with the , which says...  evidence that you can support yourself during your trip, eg bank statements or payslips from the last 6 months  (Note 'eg' is a Latin abbreviation meaning "for example"; this appears to be optional rather than a fixed requirement.) Question: How should someone interpret this such that the chances of success are maximized? How many statements should I submit? What are they looking for and what do my bank statements tell about me?


I have 1 years of experience in asp.net. I have worked with MVC, asp.net, C#, JQUERY, CSS.  I want to learn something new so I have chosen SharePoint because of market demand and salary.  I am very much confused that I have to remain in dot net or I have to switch to SharePoint?  The following questions are in my mind, if someone can help me to come out of this confusion, I am very thankful.   Future of SharePoint?, is it possible that after few years SharePoint demand will go very down as flex? Is SharePoint difficult to learn?  Is SharePoint programming is very difficult from asp.net? I heard that nobody give SharePoint work to a fresher, is it so? I did not get any SharePoint video tutorial can someone provide me the links?

I am a .NET developer who builds web apps and I’m thinking of learning SharePoint 2010 and change my career to SharPOint development. Why? Because web development is widely focused and I never seem to be an expert in any one technology. There’s just too much to learn. At least with SharePoint I can use my existing C# and database skills in one platform.   My question is this: Is it a good career move to focus on one platform such as SharePoint? I sure hope you say yes.


How can install MariaDb on ubuntu 14.04 , i have searched in Ubuntu Software Center but its not there. Then checked MariaDB official website but its clearly mentioned there are some issues in .deb file for ubuntu.  Can I download the .rpm file which is for redhat and then onvert it into .deb by using Alien command.  Would it be fine?   As mentioned  . Ubuntu 14.04 LTS continues to provide official support for MySQL 5.5. Three other community supported alternatives of MySQL are also included:  MariaDB 5.5 - a drop in replacement for MySQL 5.5.

What is the most stable/safest way to install MariaDB?


If I cast  on my 3/1 creature and to counter my opponent uses  to return it to my hand, is my Tormented Thoughts wasted?

My friend had a  on the board with 10 counters on it.  If I destroy it and he sacs it in response to gain the life, is there anything that can be done about that?  Like, can I put another destroy artifact on the stack to resolve before his sac resolves?


Please consider this code:  \documentclass[11pt]{article}  \begin{filecontents*}{table.dat} type    v1  v2  v3 v4 v5  v6 v7 t1 0 0 0 0 0 0 0 0 0 0 0 0 0 6 t2 5 17 4 0 0 0 21 0 133 4 91 0 1 93 t3 18 0 0 0 18 0 15 0 0 111 37 0 0 48 t4 12 0 14 0 0 0 18 0 38 0 38 0 0 30 t5 3 69 4 0 64 0 69 0 80 29 6 0 1 21 t6 28 4 10 0 10 0 33 6 58 0 48 0 21 29 t7 25 144 2 0 0 0 180 0 200 0 193 0 52 370 \end{filecontents*}  \usepackage{pgfplots} \pgfplotsset{compat=1.3}  \usepackage{lipsum}  \begin{document}   \lipsum[1]   \begin{figure}[h]     \noindent     \begin{tikzpicture}     \begin{axis}[       ybar=2pt,       bar width=3pt,       width=\textwidth,       height=3cm,       axis lines=none,       ytick=\empty,       symbolic x coords={ t1, t2, t3, t4, t5, t6, t7 }     ]      \addplot table[x=type, y=v1] {table.dat};     \addplot table[x=type, y=v2] {table.dat};     \addplot table[x=type, y=v3] {table.dat};     \addplot table[x=type, y=v4] {table.dat};     \addplot table[x=type, y=v5] {table.dat};     \addplot table[x=type, y=v6] {table.dat};     \addplot table[x=type, y=v7] {table.dat};      \end{axis}     \end{tikzpicture}   \end{figure}   \lipsum[1] \end{document}   As you can see, I have only two very high bars that make everything else indiscernible.     For various reasons I don't like the idea to use a log axis just for these two values.  Is there a way to truncate in some way the tall bars, so that they have a manageable height? In contrast to just tweak the data to have a smaller bar, I'm looking for something that visually hints at this truncation.

Is there an easy way to 'break' the axis in a pgfplots environment? What I'm talking about is something like     Any minimal plot will do as an example...for example  \documentclass{minimal}   \usepackage{tikz} \usepackage{pgfplots}  \begin{document} \begin{tikzpicture} \begin{axis}[ymin=0, ymax=80] \addplot {x*0};  \addplot {x^2+50}; \end{axis} \end{tikzpicture}  \end{document}   For example, in the below plot,    I want to break the axis from around y = 10 to y = 40.   Any ideas? Does PGF have this functionality? A search for `break' in the manual doesn't yield anything.


I'm trying to learn templates in c++ and i came across with a doubt that i can't find answers for. I'm sorry in advance if this is not a proper question.  If i have the following code:  template< class T > T func( T a, T b ) {     return a + b; }   And then:  int number = func( 2, 3 );   Will number simply be set to 5 or will a function  int func( int a, int b ) {     return a + b; }   be generated?  I need to know if i can make a template that checks if a certain string is in a file.

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


I am looking for a JavaScript RegEx that matches all woff and woff2 files that start with a particular String, i.e. MyFont.  The following examples should match:  MyFont-bold.woff MyFont-light.woff2   The following example should not match:  GoogleFont-bold.woff SomeOtherFont-light.woff2 MyFont-something.css

I don't really understand regular expressions.  Can you explain them to me in an easy-to-follow manner?  If there are any online tools or books, could you also link to them?


I've been playing COC for about 2 years now. I upgraded my phone last week, I easily transfer my TH10 account on my new phone.   Now, I want to make a new account on my old phone but every time I download it, the old base is still appearing.  I did the reset settings in SETTING>GENERAL>RESET and nothing happened. I also logged out my Game Center, iCloud, AppleID.. and create a new one but still every time I download Clash of Clans, my old account is still there.  What do I do next?

I downloaded Clash of Clans to my iPad (iOS 7) this past weekend and started playing.    Of course, after a couple of hours I realized I made some newbie mistakes that are fatal to my future success.  I wanted to restart, but it seems the only way to do so is to reset the device which I really would like to avoid.  After some Googling I tried the option of logging out of Game Center and logging in with a different Apple ID.  But, sadly, CoC re-launched back into the existing game.  Is there any way I can start over? Or at least start a new game under a different account on the same device?


I'm writing a term paper using LaTeX that includes a number of figures created using external tools. These figures are available in both bitmap and vector formats. Ideally I'd like to use the vector versions, of course, but these are fairly chunky (up to 40 MiB apiece), and if I include these rather than the bitmap versions, the resulting PDF for the paper is well in excess of 100 MiB.  This isn't a problem per se. However, I have to submit the paper in both paper and electronic form (by email), and emailing such a large file could be an issue. I've therefore wondered if there is an easy (!) way of producing two versions of the paper, one for printing (using vector graphics) and one for emailing (a ,,web version´´, using bitmap graphics) from the same TeX file. The TeX file is already suitably prepared, I merely need to ,,flip a switch´´ to produce either version, but I cannot produce both at the same time, with different names.  I'd like to avoid using makefiles etc.; my workflow's based on TeXstudio on Windows, so something that's pure TeX (well, LaTeX is fine) would be best. I've looked at \input and \include, but I'm wondering if there's any tricks or Best Current Practices where ideally, I only need to run xelatex termpaper.tex or so and get both termpaper-web.pdf and termpaper-print.pdf.  I do apologize for the relatively open-ended question. Thanks in advance!

I am writing a document for a software which has two versions. Most of the content in the document is the same except few specific details. Right now, I am using the conditionals to build the document for a specific file, like so,   \usepackage{etoolbox} .. \newtoggle{version5}     \togglefalse{version5}  \iftoggle{version5} {     \title{Version 5 document} } {     \title{Version 6 document} }  \begin{document}     \chapter{Chapter 1}         \iftoggle{version5} {             \section{Version 5 section}         } {             \section{Version 6 section}         } \end{document}   This works prefectly, but the problem is everytime I need either of the document, I need to toggle the variables each time. Is there a way to build both the document in a single run?


are there any concrete rules  that say wich words(parts of speech) in a title should start  with a  capital ? what would be a correct capitalization for the title of this question ?

Are there any concrete rules that say which words (parts of speech) in a title should start with a capital letter? What would be a correct capitalization for the title of this question?


I am not sure I understand how stack works...   Is there any performance difference between static and dynamic arrays, excluding the time needed for memory allocation?  char* data = (char*)malloc(100); char data[100];  From what I understand stack is only a few MB. Why is the stack limited? Why have stack and heap and not a single place to store memory? Should all arrays be allocated dynamically? For example, having one array with size 1KB on stack, is it a good idea?

Programming language books explain that value types are created on the stack, and reference types are created on the heap, without explaining what these two things are. I haven't read a clear explanation of this.  I understand what a stack is. But,    Where and what are they (physically in a real computer's memory)? To what extent are they controlled by the OS or language run-time? What is their scope? What determines the size of each of them? What makes one faster?


We have a journey which lasts 6 months, we have noticed some customers during that time update their email addresses. When this happens they continue to receive comms to their old email address. How can we resolve this?

I have scenario where contact added/injected to Journey Builder. Journey duration is one week and there is one email going every day.  Let say contact A injected to journey on Monday with email E1, on Wednesday contact A's Email changed to E2, Thursday onward which email will be used to send email until end of journey.   Salesforce ID is subscriber key.  Kind Regards


I am using this command  sudo apt-get update && wget https://minergate.com/download/deb-cli && mv deb-cli minergate-cli-release.deb && sudo apt-get install -y gdebi && sudo gdebi minergate-cli-release.deb && screen minergate-cli -user someone@any.com --xmr   So first I need force yes; when prompted with "do you want to install software package?" y/n   I need to auto select y  Secondly I need to run this whole command in the background. It takes a long time to install.

I always see commands like this  apt-get -y install    What is the -y tag for and what is the difference between apt-get install with and without the -y tag?


I tried to install jdownloader, I added the ppa then got error Unable to locate package jdownloader-installer  when I tried to install it.    sudo apt-add-repository ppa:jd-team/jdownloader  sudo apt-get update  sudo apt-get install jdownloader-installer

When I try to install any package through the command line, I get an error.   $ sudo apt-get install <package> Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package <package>   Can anyone help me on this?


I am using eclipse neon. I canceled one SVN commit due to bad network (force quit). But now, when I tried to commit those files again I'm getting exception saying ,  org.apache.subversion.javahl.ClientException: svn: E155004: Working copy 'XXXX...' locked  When I tried Team -> cleanup  it failed due to same locking issue. Tried svn cleanup from terminal. Then I got "bash: svn: command not found..".  Is there any way to change this lock issue?   Please help me  Thanks in advance

I get this error when I do an svn update:     Working copy XXXXXXXX locked Please   execute "Cleanup" command   When I run cleanup, I get     Cleanup failed to process the   following paths: XXXXXXXX   How do I get out of this loop?


float ff = (float)31.15;  double dd = 31.15;  var frst = Math.Round(ff, 1, MidpointRounding.AwayFromZero);  var drst = Math.Round(dd, 1, MidpointRounding.AwayFromZero);   frst: 31.1  drst: 31.2  Can someone explain why?

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


So all answers I've seen have to do with multiplying both sides by $(k+1)$ and continuing from there. The way I thought if it is different so I'd like to ask if it correct and if not why.  Note: I did look around the site a bit but I didn't find satisfying answers, sorry if it's a common question and I just missed answers.  My answer: After confirming its true for some $n$ values and assuming $(1+x)^k \geq 1 + kx$, I went like this:  I tried checking whether $(1+x)^{(k+1)} \geq 1 + (1+k)x$ is true  We have: $(1+x)(1+x)^k \geq 1 + x + kx$  Divide by $1+x$ as $x > -1: (1+x)^k \geq 1 + \dfrac{kx}{(1+x)}$  I add and subtract $kx$ and I have: $(1+x)^k \geq 1 + kx + \dfrac{kx}{(1+x)} - (1+x)\dfrac{kx}{(1+x)}$.  Now as we know $(1+x)^k \geq 1 + kx$ is true I just have to prove $\dfrac{((1+x)kx - kx)}{(1+x)}$ is greater than 0.  So: $\dfrac{(kx + kx^2 - kx)}{(1+x)} = \dfrac{kx^2}{(1+x)}$ which is greater than 0.  In other words $(1+x)^{(k+1)} \geq 1 + (1+k)x$ is true.  Notes: Sorry if I didn't explain something well enough, English isn't my mother tongue so explaining math in it is harder than simply talking.   Also, I understand the other method, I was just wondering if this is wrong.

I'm asked to used induction to prove Bernoulli's Inequality: If $1+x>0$, then $(1+x)^n\geq 1+nx$ for all $n\in\mathbb{N}$. This what I have so far:  Let $n=1$. Then $1+x\geq 1+x$. This is true. Now assume that the proposed inequality holds for some arbitrary $k$, namely that $$1+x>0\implies (1+x)^k\geq 1+kx,~\forall~k\in\mathbb{N}\setminus\{1\}$$ is true. We want to show that the proposed inequality holds for $k+1$. Thus multiplication of $(1+x)$ on each side of the above inequality produces the following result: $$(1+x)(1+x)^k\geq (1+kx)(1+x)\implies (1+x)^{k+1}\geq 1+x+kx+kx^2\cdots\cdots\cdots$$  I'm not sure where to go from here.


Many years back I read a short science fiction story about sold love. If memory serves, a man comes to a pleasure-planet. He passes several attractions, the weirdest one being a place where you can kill women (with guns, hand grenades, etc.). He finally ends up at a place where he is promised to be sold "true love", for a limited time only.  He buys the package and indeed falls in love with the woman presented to him. They share some wonderful days until his time runs out. The woman returns to the company and he's desperately trying to get her back.  Due to his efforts, the salesman of the love-company finally admits that the love sold is controlled by some "effects" and not natural, though in every way the same as true love. Finally the frustrated man walks off and once again passes the place where you can kill women...    I've searched for this story for a while now. I don't think I've grabbed the whole concept of it back when I read it and I really want to read it again.  Any help finding it would be highly appreciated!

I'm pretty sure this was in an anthology of older stories that I read in a paperback in the 90s, although the book may have dated from when my parents were growing up in the 60s and the 70s. The protagonist is a country boy who goes into town. There a sort of a Coney Island setup with booths and items for sale. I remember there were prostitutes named something like "pork-upines" with vaginal openings scattered all over their bodies as well as a shooting gallery where you practiced on live targets, although I'm not entirely certain if they were robots of some sort, or genetically modified. The protagonist is horrified at the excesses of the city, but samples the wares of one of the prostitutes, falls in love with her, and buys her freedom.       Somehow, in the course of the story, he becomes disillusioned and he arranges for her to be a target at one of the shooting galleries. The story ends with him aiming his rifle at her.   I know it's a very vague description, but I'm hoping those salient points strike a memory in someone. It was in English. I read it while in the United States somewhere in the 90s, and I'm pretty sure it was one one story in an older paperback, the sort with the cheap paper that browns with age. It's also possible that it's one of the shooting gallery targets he purchases, although I'm pretty sure it was one of the prostitutes.


I have a 2-language doc (arabic and english).  Sometimes it is primarily English, sometimes primarily Arabic.  When the doc was primarily Arabic, I changed the Arabic chapter headings with code (see below) I obtained from @ahmed-el-bokl.    \gappto\captionsarabic{\renewcommand{\chaptername}{الباب}} \def\xwords#1{\ifcase\value{#1}\or الأول\or الثاني\or الثالث\or الرابع\or الخامس\or \else أحتاج إلى المزيد من ترقيمات الأبواب بالحروف في ملف \fi}   However, some of my documents are primarily English, so I would like to execute Ahmed's code only if a flag (arabicstudent) is set, otherwise keep the document English.  To do this I have a newcommand called whichlanguage inside which is a renewcommand which is only called if the flag is set.  Below is my MWE.  But xetex sees the #1 inside the inner renewcommand and complains that I did not specify arguments in the outer newcommand.  How do I fix this?  \newcommand{\whichlanguage} { \ifarabicstudent \setmainlanguage{arabic}      %here is Ahmed's code again     \gappto\captionsarabic{\renewcommand{\chaptername}{الباب}}     \def\xwords#1{\ifcase\value{#1}\or     الأول\or     الثاني\or     الثالث\or     الرابع\or     الخامس\or     \else     أحتاج إلى المزيد من ترقيمات الأبواب بالحروف في ملف \fi}  \else \setmainlanguage{english} \fi  }

In  we learned how to use \newcommand within a command definition with another \newcommand, when the name of the inner command needs to contain a parameter of the outer command. Now, suppose I want to do the same, but for the inner \newcommand to also have parameters, i.e. I want the following code to work:  \newcommand{\defsilly}[1]{%   % define a command named silly#1 , taking a single parameter } \defsilly{willy} \sillywilly{theparameter}   Motivation: I'm writing a thesis document class, which has a bunch of the following kind of command pairs:  \newcommand{\iitthesis@authorEnglish}{Name of Author} \newcommand{\authorEnglish}[1]{\renewcommand{\iitthesis@authorEnglish}{#1}}   I want to replace each of these pairs with something like:  \iitthesis@thesisdatafield{authorEnglish}{Name of Author}   This defines both the above commands.


Let $𝐴$ be an $𝑛×𝑛$ matrix and $𝑂$ be the zero $𝑛×𝑛$ matrix.  a) Suppose that $𝐴^2=𝑂$. Prove that $𝐼+𝐴$ is invertible.  b) Suppose that $𝐴^𝑘=𝑂$ for some $𝑘$. Prove that $𝐼+𝐴$ is invertible.  I attached a picture of what I have done for part a but I think it's wrong and I have no idea what to do for part b)

Given a ring $R$ (with unity), prove that if $a \in R$ is nilpotent, then $a+1,a-1$ are both invertible.   Suppose $a^n=0$. Then $1=1-a^n=(1-a)(1+a+\ldots+a^{n-1})$, so $1-a$ is invertible.  If $n$ is odd we can use $1+a^n=(1+a)(1-a+\ldots+a^{n-1})$.  But what if $n$ is even?


I agreed to download Windows 10 and now it is downloaded and ready. I want to be able to control when it installs, possibly weeks from now. I'm currently on Windows 7.  I have been prompted with an option to choose which one of the next 3 days I would like the installation to happen on. There was no option to postpone it for longer, so I picked the third day.  However it seems like it will install the next time I restart, and I don't want that to happen. (see screenshot)  How can I cancel the upgrade?

I cancelled the Microsoft Windows 10 Reservation and uninstalled KB3035583, but Windows 10 is still trying to install.   After I uninstalled KB3035583 and restarted my laptop as instructed, I could not find KB3035583 to hide it.   Now Windows 10 is sitting in my Windows Update saying that it will install when I restart my computer.


I don't know what causes it, but sometimes zooming with the mouse wheel in the 3D View becomes very very slow. When I create a new 3D View it's back at normal speed, restarting Blender doesn't help though.  What could cause this and how can I solve it?

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 am just coding various scenarios for static, const and global variables, to see where they work and where they don't.  Following code is giving me weird collect2: error: ld returned 1 exit status.  Code:  #include <iostream> #include <string> #include <vector>  using namespace std; const static int gl = 4; class Static{     private:             int nonStatic;             const static int count = 10;             //constexpr static string str;             static vector<string> svec;     public:             static vector<string> initVector();             void printVector();             Static(int s=0): nonStatic(s){}             ~Static(){}  };  vector<string> Static::initVector() {         for(int i=0; i<5; i++)     {             string str;             cin>>str;             svec.push_back(str);     } }  void Static::printVector() {     for(auto const i: svec)             cout<<i; }  int main() {     Static state(4);     return 0; }   It shows the following ld error message:  /tmp/ccsX2Fre.o: In function `Static::initVector[abi:cxx11]()': StaticTests.cpp:(.text+0x4e): undefined reference to `Static::svec[abi:cxx11]' /tmp/ccsX2Fre.o: In function `Static::printVector()': StaticTests.cpp:(.text+0xc4): undefined reference to `Static::svec[abi:cxx11]' collect2: error: ld returned 1 exit status

Can anyone explain why following code won't compile? At least on g++ 4.2.4.  And more interesting, why it will compile when I cast MEMBER to int?  #include <vector>  class Foo {   public:       static const int MEMBER = 1;   };  int main(){       vector<int> v;       v.push_back( Foo::MEMBER );       // undefined reference to `Foo::MEMBER'     v.push_back( (int) Foo::MEMBER ); // OK       return 0; }


I have been reading the following link about an example of the EM algorithm applied to the tossing of a coin. The link is:    In the example states that we have the record set of heads and tails from a couple of coins, given by a vector x, but that we do not count with information about which coin did we chose for tossing it 10 times inside a 5 iterations loop.  The problem that I have is with the following figure:    For what it says in the tutorial, it should converge to values of theta(A)=0.80 and theta(B)=0.45. At the beginning, it starts with two values of theta at random that are theta(A)=0.60 and theta(B)=0.50. The question that I have is from where does the values of 0.45x, 0.55x, 0.80x, 0.2x and so on appears? also how I can transform that to each of the values that appear on the table for Coin A and Coin B. In conclusion, I need details on how to obtain those values. Thanks

$X_1, X_2 \dots X_n$ represent independently observed Bernoulli random variables.  $Z_1, Z_2, \dots Z_n$ are unobserved.  $Z_i | \theta_i \sim N(\theta_i,1)$  $\theta_i \sim N(\epsilon, \sigma^2)$  $X_i = \begin{cases} 0 &  Z_i \leq u \\ 1 & Z_i > u \end{cases}$ where $u$ is known.  Show that the EM sequence for estimation of $\epsilon$ is given by:  $\epsilon^{t+1} = \frac{1}{n} \sum_{i=1}^n E[Z_i|X_i, \epsilon^t, \sigma^2]$  $\Phi$ represents CDF of standard normal.  Attempt  $Z_i \sim N(\epsilon, \sigma^2+1)$   \begin{align*} f(X,Z| \epsilon, \sigma^2) &= \prod_{i=1}^n p_i^{x_i} (1-p_i)^{1-x_i}\\ p_i &= P(Z_i \leq u)\\ &=\Phi(\frac{u-\epsilon}{\sqrt{\sigma^2+1}}) \end{align*}  Complete log likeihood = $\sum_{i=1}^nx_i \log p_i + (n-\sum_i x_i) \log(1-p_i)$  I am not able to proceed further.


Innocents who Bing and Google for StackExchange/StackOverflow questions are not seeing Stack_ URL at the top of the search results.  The offenders (I presume) are using the StackExchange API and republishing content for their own benefit (Ad views, and click throughs, or attack vectors).   Is this a breach of their account/API usage agreement? Should StackExchange be working their SEO magic to get a higher ranking? Is there anything we can really do?   Offenders I've found today:        (more legit than others)

of Stack Overflow, all content posted on Stack Exchange sites by their users (i.e. you wonderful people) has been provided to the whole universe under . For my fellow non-lawyers, that license basically means:   Anyone can use any Stack Exchange posts at any time without having to ask for permission Making money off of the copied content is permitted You don't even have to copy stuff from here verbatim; you can just use it as a starting point and make whatever edits you want There are just two rules you have to follow:   You have to provide . Simple links to the original post and author info are just fine. You have to  and allow other people to use your content, as long as they follow these very same rules. How meta!    (If you ever forget any of that, and want to refresh your memory, the license info is linked to in the footer of every page.)  There are, in fact, a lot of people who republish varying amounts of our content for assorted reasons. Unfortunately, there are some Stack Content Republishers Attributing Poorly and/or Excelling at Ranking (SCRAPERs, for short).  In this context, "attributing poorly" means any use that doesn't follow our attribution rules or make any other reasonable attempt at give credit. This can get pretty egregious; I've seen SCRAPERs that not only don't link back to SE originals, but also use fake author info and post dates to make it harder to find originals. By "excelling at ranking," I'm referring to copycat sites that end up higher in Google results than the original SE sites do for the same content. That's not necessarily wrong, but in some cases, it indicates inappropriate SEO hackery.  So, the question is: what can you do if you spot a SCRAPER?


Can someone tell me if the transfer function for this circuit is:  R2/[(w^2 * C^2 * R1) - jwC]  thanks

Some one please help me with this question. I am getting -10.5 as the wrong final answer.I found the formula in the following slide.Since the result was coming out in complex number i got its modulus.That is how i ended up with a 10.5 (2 * 5.25).


I would like to use the symbol '𝔖' in Latex (used for ).  Any ideas?

I know what my symbol or character looks like, but I don't know what the command is or which math alphabet it came from. How do I go about finding this out?


I am aware that you can search for multiple tags such as [css] and [jquery], which will show questions with both of those tags. But is there a way to search with 'or' rather than 'and'? So that the search will show any question that has any tag that's listed?

It would be awesome if I could pass a list of tags to search for out of which I am given questions which are in either of the categories.


One of my coworkers has provided me with a Bash syntax that I am unfamiliar with.  My Google foo has failed me on figuring out what it does and why/when I should use it.    The command that he sent me was of this form:  someVariable=something command   Initially, I thought that this was equivalent to the following:   someVariable=something ; command   Or  someVariable=something  command   But this doesn't appear to the be case.  Examples:   [Jan-03 11:26][~]$ # Look at the environment variable BAZ. It is currently empty [Jan-03 11:26][~]$ echo $BAZ  [Jan-03 11:27][~]$ # Try running a command of the same format     [Jan-03 11:27][~]$ BAZ=jake echo $BAZ  [Jan-03 11:27][~]$     [Jan-03 11:27][~]$ # Now, echo BAZ again. It is still empty:     [Jan-03 11:27][~]$ echo $BAZ  [Jan-03 11:27][~]$     [Jan-03 11:28][~]$     [Jan-03 11:28][~]$ # If we add a semi-colon to the command, we get dramatically different results: [Jan-03 11:28][~]$ BAZ=jake ; echo $BAZ jake [Jan-03 11:28][~]$ [Jan-03 11:28][~]$ # And we can see that the variable is actually set: [Jan-03 11:29][~]$ echo $BAZ jake [Jan-03 11:29][~]$   What does this syntax do?  What happens to the variable that has been set?  Why does this work?

Is there any standard that covers the portability of running a command after variable assignment on the same line?  APPLE="cider" echo hi   How portable is something like that? Where will it work and where won't it?   Also: my shell scripts start with #!/bin/sh if that makes any difference.


When we use more than one adjective, e.g.     The big, red, bouncy balloon.   The list of three adjectives {big, red, and bouncy} is a list, so by rights it should be separated by commas, with an "and" between the last two terms.  If somebody asked us to describe the balloon we would without hesitation say that it is "big, red and bouncy".  Going by the rules, the correct form for the first phrase given above would be to write:     The big, red and bouncy balloon.   But we virtually never see this.  In lists of adjectives and is used as the exception, whereas in lists in general, to exclude it is the exception. Is it a correct technicality to include the "and", which nobody observes, thereby making it acceptable to exclude the "and" on the basis of common usage?  And to write the best English we can, should we be including the "and" in lists of adjectives?

He called her, emailed her, texted her, tweeted her—all to no use.   Strictly speaking, I would need to write texted her and tweeted her, but I'm omitting and to convey a rhythm and sense of urgency. What do you call this kind of construction, and is it accepted grammar (at least for creative writing, if not in an academic context)?


I'm trying to render an animation I made using blender models and textures, but all I get is a grey screen on the Rendered viewport and output.  On the left there's a Rendered Camera view, and on the right my objects in the Solid Viewport   I tried doing some researching to see what I was doing wrong, but unfortunately I couldn't find anything. Here's what I've tried:   See if something is up with lighting and camera, and apparently it's not; Disabling "Sequencer" from Render > Post Processing; Switch from Blender Render to Cycles Render, but it didn't worked either and the output it's the same; Copy one of the objects from the original scene and place it on a new Blender file, containing just the starting cube. When I rendered through Blender Render, I could only see the cube. However, when rendering through Cycles, it rendered both objects with their following materials.   Here's the experiment on a new Blender file, and the Rendered view shows both objects   Do you guys have any suggestions of what my problem might be?  EDIT: addded .blend file below.

I have a model of a building with a sidewalk around it.  Both show up when I switch to rendering mode in both Blender Render and Cycles Render mode.  But:  when I hit F12 for a final proper render, the building shows up -- but the sidewalk doesn't.    I've checked the normals and I thought the normals seemed pointed in the right direction.  I've set the Clipping on the Camera to a high number.  I removed all the materials from the sidewalk and added a new material-- the problem persists.  I've exported the blend as an FBX file and the Sidewalk shows up fine in Unity.  Just in final renders, it doesn't show up.    Here is a blend file: .  I tried to destroy everything unrelated to the issue and label things in a clear way.    Thanks.


Overstayed in Philippines for 18 years. I wanna go back in Hawaii. But i have no money. Also my passport lost 3 years ago. I don't know what to do. Not enough money to go home.

I'm a U.S. Citizen and I have been overstaying in the Philippines for 5 years. I want to go back to U.S what's the penalty?   I don't have enough money to pay a big fine, is there a way to avoid that?


$8x\equiv 21\pmod{24}$  I am having problem solving this linear congruence because 8 is even and 21 is odd.

For example: $$7x \equiv 1 \pmod{31} $$ In this example, the modular inverse of $7$ with respect to $31$ is $9$. How can we find out that $9$? What are the steps that I need to do? Update If I have a general modulo equation: $$5x + 1 \equiv 2 \pmod{6}$$ What is the fastest way to solve it? My initial thought was: $$5x + 1 \equiv 2 \pmod{6}$$ $$\Leftrightarrow 5x + 1 - 1\equiv 2 - 1 \pmod{6}$$ $$\Leftrightarrow 5x \equiv 1 \pmod{6}$$ Then solve for the inverse of $5$ modulo 6. Is it a right approach? Thanks.


Cosmic jets are jets of matter ejected from super massive black holes. The gravitational pull of a black hole is so high that even light can't escape it. Yet particles with mass traveling at speeds slower than the speed of light are ejected out. Why does this paradox exist? Is the laws of physics violated? (A humble doubt from a layman)

We've heard it many times, nothing can escape the gravity of a black hole, even light once it's past the event horizon.  If this is true, how can a black hole emit anything?  are massive black holes that have consumed enormous amounts of matter and energy, and then blasted it back out into the universe.  How is this possible?  Time stands still in a black hole, that in itself should stop anything from moving.


Is there a way i can tell if i am being observed by an admin who is using apple remote desktop (ARD) ?   Is there an icon that will pop up in the dock / top bar ? Or is there a port I could check to see if there is traffic passing through it ?

Currently I have no way to know if my machine is being remotely viewed by our tech support, and would prefer to know, given the massive privacy breach that would entail should this be happening. I am running Mac OS X Snow Leopard.  Running  ps -A | grep Remote   I know this service is running:  /System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/MacOS/ARDAgent   My knowledge of administration of Macs on a network is limited, so I don't know what tools allow this.


stack = ['','','','','','']    global first    global last    first = 0    last = 0    print(stack)    while True:        def push():            if 0 <= last:                stack[last] = 'D'                last = last + 1                if last == 6:                last = -1            else:                print("The stack is full.")                print(stack)         def pop():            stack[last] = ''            last == stack[last-1]            print(stack)            if first == last:                print("The queue is empty")        a = input("Push or pop. ")        if a == 'push':            push()        elif a == 'pop':            pop()   I've assigned last as a global variable yet I get this error UnboundLocalError: local variable 'last' referenced before assignment. Considering I've made last a global variable I don't understand why the error is suggesting otherwise, any solutions?

How can I create or use a global variable in a function?  If I create a global variable in one function, how can I use that global variable in another function? Do I need to store the global variable in a local variable of the function which needs its access?


Problem  When looking through the question listings, it's frustrating having read an entire question's title to then at the end find "[on-hold]" or "[duplicate]" etc. And so wasted time reading the title as I won't be looking at the question.    The area (end of title) is often quite busy with the question's snippet text close below, and previous question's user badges/profile image close above. So it's usually not immediately obvious without glancing over to see if a question is answerable or not (ie not on-hold etc).    I sometimes glance at the right side first, but then that's pointless with the ones which aren't closed/on-hold etc.    Request  Can we have some sort of unique highlight specifically to show when a question is on-hold, dupe etc, and so is not answerable?    Such as on-hold/closed/duped questions have their entire listing all light grey background, or some border, or whatever?    Even the notifications ([on-hold], [duplicate] etc) being a different colour to the title would be a massive improvement and make them stand out.    Actually, the [on-hold], [duplicate] etc being a different colour to the rest of the title would also separate them from user text and make them look more like serious sitey-notification-stuff. A possible double benefit.    Frequency  It might not be much of a problem on some tag(s), but there are plenty of tags where questions are closed/on-hold quite often, and this issue is frequent.    Spend a day in SO [php] and you'll see the issue. Programmers site seems to suffer a similar issue, as all the data on the question list page is quite squashed together (not a problem in itself, just worsens the issue I've raised here).      Note: Maybe I'm just getting old, and/or need new glasses.    EDIT  My question is different to the proposed dupe because the other question suggests having a yellow notification colour on the left hand side when a question is on-hold/dupe etc.     The suggestion in the other question does not solve my issue as then I'd have to look left on every question to check if the question is answerable or not. This is no better than my having to look right, as currently. The proposal in the other question is not ideal because it introduces another colour in an area already containing some colours. It could get confusing having too many colours there. I have suggested very different solution ideas.

When browsing on questions that I would like to answer or flag, I now ended up to a question that was put on hold. I had to open the question to realize it was not an eligible one and it was already put on hold. So nothing to do about, basically.  On software design one rule is to avoid clicks. If I look for questions to answer, I normally skip ones marked as green on list because these have an accepted answer already there. For put on hold questions the only indicator is maybe a flappy title, put for being sure there is no need to even flag the question, I would like to see a yellow color on status (votecount, answer count) box to tell the question is on hold. That way my moderating and answering double focus would immediatedly go for the next one. Desicion of open or not would be easier.  (You may discuss the color, light grey is ok, too.)


How i can show that if $\lim_{z\rightarrow\infty}\frac{|f(z)|}{|z|^{m}}=0$ then $f(z)$ is a polynomial of degree $< m$? Note: $f(z)$ is a polynomial in $\mathbb{C}[x].$ Thanks,

I can't prove this statement, can anybody show me how to prove it?    $$f:\mathbb{C}\rightarrow \mathbb{C} \in \mathcal{O}(\mathbb{C}), \exists n\in \mathbb{N}, R >0 , M>0 : |f(z)| \le M|z|^{n} \ \ \forall |z|>R \Rightarrow \deg(f)\le n $$  To show is that if there exists such an $M$, that then $f$ is a polynomial of max degree $n$. I started like this:   $$f(z) = \sum_{n=0}^{\infty} a_n (z-z_0)^n$$ So if I put this into the inequality: $$|f(z)| = \left| \sum_{n=0}^{\infty} a_n (z-z_0)^n \right| \le M |z|^n .$$


I have data like :  Emp Code | Name | Qualification | Completed Year 10000001   Ram    B.E               2005 10000001   Ram    M.E               2007 10000002   Sita   B.E               2003 10000002   Sita   MS                2005 10000002   Sita   Ph.D              2010   I want to convert like  Emp Code | Name |UG_Qualifi | Completed Yr| PG_Qualifi | Completed Yr 10000001   Ram    B.E               2005      M.E               2007 10000002   Sita   B.E               2003      MS                2005

Maybe this question has been asked already (it should be quite simple). I've Googled loads of phrases  (PIVOT, ROWS to COLUMNS, TRANSPOSE &c.) and all I get is  TSQL this, TSQL that and or Oracle this, Oracle that, proprietary function this, proprietary function that well, you get the picture.  I have a simple table structure - if it was any simpler, it'd be a list :-) - i.e. it's two columns.  stock_date       sku ----------       --- 2016-06-01         0 2016-06-02       123 2016-06-03       123 2016-06-04       123 2016-06-06       123 2016-06-07       123 2016-06-03       245 <... &c...>   There may be many thousands of sku's but the date range will be at most a month or so, but can vary, so the code needs to cater for that.   So, I want to make the stock_date field a column.   sku     1   2   3   4   5   6   7 ---     -   -   -   -   -   -   -  123     0   Y   Y   Y   0   Y   Y 245     0   0   Y.... &c.   Ideally, the code would be dynamic and would work with any server (even MySQL).   But if it has to use common table expressions and/or window functions, that's  OK but not proprietary crosstab or pivot functions.


I download a few items for my school work but cannot launch them. It keeps asking which program to I want to open with. It isnt like windows when it automatically knows.

I have absolutely no experience with Linux, and I desperately need to get my computer back up and running again with Windows.  How do I remove Ubuntu and reinstall Windows?    Editor's note: many of the answers are about removing Ubuntu from dual-boot but keeping Windows (which is a bit complicated), while other answers are about removing Ubuntu from single-boot (which is easy: basically just format the disk while installing Windows). The question as written is ambiguous between dual-boot or single-boot.


I am new to MFC and I am trying to change the size of my objects with respect to form. For this, I am using single document project and in View.cpp and MainFrm.cpp I have changed form size.    BOOL CMainFrame::PreCreateWindow(CREATESTRUCT& cs) {     if( !CFrameWnd::PreCreateWindow(cs) )         return FALSE;     // TODO: Modify the Window class or styles here by modifying     //  the CREATESTRUCT cs     cs.cx = 400;     cs.cy = 400;     return TRUE; }   and in View.cpp, I have fixed the initial size of screen as given below.  BOOL CDCDrawingView::PreCreateWindow(CREATESTRUCT& cs) {     // TODO: Modify the Window class or styles here by modifying     //  the CREATESTRUCT cs     cs.cx = 400;     //const wchar_t a = cs.cx;     width = cs.cx;     cs.cy = 400;      height = cs.cy;     return CView::PreCreateWindow(cs); }   Here comes the problem, I want to draw the objects and I want to change the size of those objects with respect to size of form by using mouse. The form is able to change its size but I dont know how to update the form coordinates. I have attached the initial form and and form after changing size by mouse. initial form is given below.  and form after changing size by mouse is given below.  could someone please tell me how to change the objects with resizing form? Thanks in advance.

I am writing a program which has two panes (via CSplitter), however I am having problems figuring out out to resize the controls in each frame. For simplicity, can someone tell me how I would do it for a basic frame with a single CEdit control?   I'm fairly sure it is to do with the CEdit::OnSize() function... But I'm not really getting anywhere...  Thanks! :)


Consider the below syntax :      #include <iostream> int main() {   std::cout << 1["ABC"] << std::endl; }   The program outputs B which leads me to believe that it behaves as "ABC"[1]. Is that possible, what is the reason behind this ?

As Joel points out in , in  (aka: K & R), there is mention of this property of arrays in C: a[5] == 5[a]  Joel says that it's because of pointer arithmetic but I still don't understand. Why does a[5] == 5[a]?


Windows 8.1 x64  In apps like the Windows Notepad and Notepad++, when using the font Courier New, Bold Italic, size 9, the lowercase letter "L" is displayed in uppercase.  I don't know if the problem is the font or some Windows engine.  Where should I report this?

I have come across an issue that I feel is a  in Windows 7. What is the official process for submitting an issue to Microsoft from a consumers perspective as an end user of Windows?


I created a simple PDF file in InDesign where I placed 15 jpegs of dimensions 2480x3508 pixels of 300 dpi and included a few hyperlinks. Each page has one image. The resultant file size of the pdf with 15 pages is 7.74 mb which is huge!  Output tab looks like:    Advanced tab looks like:    On the contrary, when I create the same pdf in Photoshop (excluding hyperlinks), the resultant file size is 2.28 mb.  How can I reduce the file size in InDesign without compromising quality?

I'm doing class project that is a four-page, seven-image document with very little text. The project must be submitted as a PDF under 300 KB. However, when I export the document under the smallest file size preset and with the compression rates down to 72 dpi, I get a PDF that is 612 KB.  All my classmates are able to get it under 300 KB, so I'm confused as to why mine is so large. I'm using 5 JPGs and 2 GIFs, and each take up a 5in by 5in square in the document. They are relatively really small pictures (avg. 250 KBS) and I've even re-saved all to be under 100 KB, but the PDF size only drops to around 500 KB I transferred between InDesign CC on Mac and InDesign CS5 on Windows and wonder if that is a concern.


I have an unused Windows license for Windows Sever 2019 and the latest SAC install media. Can I instead use this license key with LTSB media, or does that require a different license?

This is a  about Licensing.    Questions on licensing are off-topic on Server Fault.  If your question has been closed as a duplicate of this question, then this is because we want to help you understand why licence questions are off topic rather than just telling you "it just is". In all likelihood, this question will not address your question directly, it was not meant to.    I have a question regarding software licensing. Can the Server Fault community please help with the following:   How many licenses do I need? Is this licensing configuration valid? What CALs do I need to be properly licensed? Can I run this product in a virtual environment? Can I downgrade this product to an earlier version? Am I entitled to feature X with license Y?