I'm working on a neural network with one hidden layer. So far I've implemented the algorithm, and I've been able to numerically verify the partial derivatives I get from back propagation. My problem is when I try to train the network by updating the weights. No matter what I do it doesn't seem like I can get my estimates to come close to the actual values.  The data I'm using is from the function:  $$ f(x) = \frac{\sin(x)}{x} $$  On a side note, I haven't added bias parameters because I couldn't get the dimensions to fit in back propagation once I added the bias in forward prop. Not sure if this is an issue since I understood the bias parameters as a safeguard against inputs equal to 0?  theta <- function(a){   a / (1+abs(a))      # Here we apply the alternative sigmoid function as our                       # non-linearity. } theta.prime <- function(a){   1 / (1+abs(a))^2 }  x <- c( 5.949110, -1.036600,  3.256780,  7.824520, -3.606010,  3.115640, -7.786960,         -7.598090,  2.083880,  3.983000,  8.060120,  7.879760, -2.456670,          -2.152720,  3.471950,  3.567960, -4.232630,  6.831610, -9.486860,  8.692330,         -1.551860,  0.917305,  4.669480, -7.760430,  2.835410) y <- c(-0.10804400,  0.78264000, -0.05313330,  0.13484700, -0.05522470, -0.05758530,          0.19566100,  0.13846000,  0.43534100, -0.16861400,  0.10625000,           0.08427310,  0.27012900,  0.44004800, -0.00880575, -0.10711400, -0.18671100,          0.01158470,  0.02767190,  0.06319830,  0.61802000,  0.87124300,          -0.25668100,  0.06160800, 0.10575700)   neuralnet <- function(x,y,theta,theta.prime,neurons){  w1 <- t(matrix(rnorm(neurons,0,.01),neurons,1))  w2 <- matrix(rnorm(neurons,0,.01),neurons,1) E <- 1 i <- 0   for(i in 1:1000){   ### Forwardpropagation ###   s2 <- x%*%w1   a2 <- apply(s2,c(1,2),theta)   s3 <- a2%*%w2   yhat <- apply(s3,c(1,2),theta)   ### Error function ###   E <- sum((yhat-y)^2)/length(x)    ### Back Propagation ###   delta3 <- (2*(yhat-y)) * apply(s3,c(1,2),theta.prime)   djdw2 <- t(a2) %*% delta3   delta2 <- delta3 %*% t(w2) * apply(s2,c(1,2),theta.prime)   djdw1 <- t(x)%*%delta2    ### Update the weights ###   w1 <- w1 - 0.01*djdw1   w2 <- w2 - -0.01*djdw2   i <- i+1   } print(i) print(E) return(yhat) }  yhat <- neuralnet(x,y,theta,theta.prime,2)

I'm training a neural network but the training loss doesn't decrease. How can I fix this?  I'm not asking about overfitting or regularization. I'm asking about how to solve the problem where my network's performance doesn't improve on the training set.    This question is intentionally general so that other questions about how to train a neural network can be closed as a duplicate of this one, with the attitude that "if you give a man a fish you feed him for a day, but if you teach a man to fish, you can feed him for the rest of his life." See this Meta thread for a discussion:   If your neural network does not generalize well, see:


Is it grammatically correct " Which is correct sentence: "Please provide me with the following documents" or "Please provide me the following documents"

I am wondering if the following sentence is correct:     We add the information their study provides with to our article.   The context is: their study provides with some information. And we add the information to our article.  I want to keep the word "add", and someone told me that "provides with to" sounds wired...


So I had this problem for some time and even after 4 months of trying to solve it, I couldn't manage to overcome my issue. Whenever I try to log in to my Minecraft Server I get the io.netty.channel.abstractchannel$AnnotatedConnectExeption: Connection timed out: no further information Error. The problem is clearly server-sided because on any other server I can log in just fine, but on my own, I can't. My first thought was that the problem might be from my computer, but when I asked my friend to join the server he received the same message. To be clear the server is running on a separate computer from the one I tried to join. When I tried to log from the localhost(IP:0) it still showed the same message so I can clearly see that the issue is server-sided. I personally tried every single method I found on the internet to fix my issue, but none seemed to work. I even tried to disable my firewall on the router and on the computer. And it still doesn't fix the issue. The server is running on paper 1.16.4 with the following plugins installed: Multiverse-Core-4.2.2, Multiverse-Portals-4.2.1, Multiverse-NetherPortals-4.2.1, Multiverse-SignPortals-4.2.0, LuckPerms-Bukkit-5.2.54, worldedit-bukkit-7.2.0, ViaBackwards-3.2.0, ViaVersion-3.2.0 and has java 8 installed.

I am getting the following error when I try to connect to a Minecraft server:  This is all servers, not just one. The error says:  io.netty.channel.AbstractChannel$AnnotatedConnectException: Connection refused: no further information: Version 1.12  I've tried:  Restarting Minecraft Restarting Computer Uninstalling and Reinstalling Mincraft Uninstalling and Reinstalling Java Altering Firewall Restarting Internet I've messed with my port, made a second windows account, reset netsh winsock Checked hosts Made a new WINDOWS account  The overlay in the bottom right is Geforce's Overlay for game capturing. I don't have any mods installed. A Mojang support ticket wouldn't help. Im desperate.


What is best case scenario for external link to open in new tab or same tab? and Why?  When do we use external link? Is it when the data is linking to some external page other than your existing page.

In usability discussions about opening website external links in new windows, with regard to the argument of "keeping users on the site" there are occasionally references to usability studies which show that users are actually likely to leave the origin site instead of returning (thus defeating the purpose of opening the link in a new window).  But I can't find actual recent published studies on this, and I've searched extensively. Though Jakob Nielson is reputed to be a foremost expert, his recommendations are old and have no citations that I can find.  Does anyone know of credible, recent, published usability studies where users were disoriented by new windows and were more likely to not return to the origin site?  Update:   I understand there are accessibility issues, but as those matters are well-documented and backed up by the WCAG, I'm not in need of evidence supporting them.  This question is intentionally specific to the argument of "I want to keep users on my site" because it is the argument which -- due to lack of supporting evidence -- I can't effectively counter in discussions with the client.  Update:  Found this . Haven't fully deciphered it, but the thesis does claim that new windows / tabs increase the cognitive burden on users.


A user seems to have zeroed in on a single spelling error shown .    Since most of the edits are not rejected, my questions is, Am I wrong to see it as minor edits?  If not, is there anything I could do besides rejecting?

I've come across a fellow that is apparently trawling SO looking for the common "calender" misspelling and correcting instances to "calendar."  He often does only that... leaving things like "Thanks" and "Regards, JoeBob" in the questions.  Should edits such as his be rejected as too minor in review?  See also a proposed spelling edit on a  that was closed as NARQ hours ago.


Many sites offer gif generation services with the option to create a transparent background behind a gif, however, when placed on a dark background, you can see edges around the animated gif. Ajax-loader.com and chimply.com (as well as many others) do not work as well as I had anticipated.  Does anyone have a suggestion for a place where I can find a true-transparent background loading gif?  Note: I cannot rely on a different color background, the site uses a preloader already and I would much prefer not to have two.

I took the loaders from  then exported them with the help of the included action to a GIF. But I have some white pixels around the loader which are really annoying when displayed on a dark background. You can see it here, in a frame I extracted from the gif:    How can I prevent those white pixels and maintain the transparent background?


Can you please let me know which of the following sentences is correct? 1 Because of this reason the Auckland is having greater productivity. 2 Because of this reason Auckland is having greater productivity.

I have been taught that it's grammatically proper to use the before countries like "Sudan and Yemen" but I was never given a reason (if there exists any, of course) when I asked why, except for "it is one of those ambiguous parts of English language that we – as non-native speakers – should just accept without trying to look for a reason". Now, I'd like to know if there is any answer to this "why" or I should keep on believing that there are no hard and fast rules when it comes to questions like these.


I have 2 tables: Order and Customer. Order has a foreign key from Customer:    I can join them in 2 different ways:  First way  Select * from [Order]  join Customer on [Order].Customer_id = Customer.id;   Second way  Select *  from [Order],Customer where [Order].Customer_id = Customer.id;   The 2 queries return the same result set which leads me to my related questions:   Which query is the better of the two? Is there a difference between them involving time execution? Why is it that when I search join examples all of them are using the first way? I learned the second type of query in college - is it wrong to use?

Is there a difference in performance (in oracle) between  Select * from Table1 T1  Inner Join Table2 T2 On T1.ID = T2.ID   And  Select * from Table1 T1, Table2 T2  Where T1.ID = T2.ID   ?


I have the following MWE for a CV, made using moderncv, and I need to display all the authors in the publications sections.  In other words, I need to replace the et al. with authors 2-5.     \documentclass{moderncv} \usepackage[]{biblatex} \usepackage[left=3cm, right=2cm]{geometry}  \moderncvstyle{classic}   \moderncvcolor{blue}         \addbibresource{Downey.bib}  % personal data \firstname{John} \familyname{Doe}  \begin{document}     \makecvtitle      \section{Education}     \cventry{start-end}{<Position Held>}{<Name of employer>}{<Place>}{<Country>}{<Description>} % arguments 3 to 6 are optional      \nocite{bib_key}     \printbibliography[title={Peer-Reviewed Journal articles}]  \end{document}   Here is the sample bibtex file.  @Article{bib_key,   author    = {\textbf{Author 1} and Author 2 and Author 3 and Author 4 and Author 5},   title     = {Research paper},   journal   = {Journal of science},   year      = {2017},   volume    = {26},   number    = {6},   pages     = {065008},   month     = {may},   doi       = {10.1088/1361-665x/aa6b66},   publisher = {{IOP} Publishing},   url       = {https://doi.org/10.1088%2F1361-665x%2Faa6b66}, }

I'm using the  package to add citations and a bibliography to my LaTeX document. I've noticed that only the first author plus "et al." is displayed for works with more than three authors. That's fine with me for in-text-citations, but I'd rather have the complete author information in the bibliography. How can I do that?


I'd like to format floating numbers in such a way that at most 2 decimals are added after the dot.  1.24 should be displayed as 1.24  1.246 should be displayed as 1.25  1.2 should be displayed as 1.2  1.0 should be displayed as 1  Using "%.2f" with printf has a drawback. For numbers with less than 2 decimals after the dot, it adds trailing 0 digits. Therefore, 1.2 is displayed as 1.20 and 1.0 is displayed as 1.00.

I keep stumbling on the format specifiers for the printf() family of functions.  What I want is to be able to print a double (or float) with a maximum given number of digits after the decimal point.  If I use:  printf("%1.3f", 359.01335); printf("%1.3f", 359.00999);   I get  359.013 359.010   Instead of the desired  359.013 359.01   Can anybody help me?


Given a distribution $\{p(X|\theta),\theta\in\Theta\}$:   how do you show the existence/non-existence of its conjugate prior? what are some general ways/principles to construct/find its conjugate prior, if there is one?  If it exists, how do you show it is unique or not?  If not unique, which one is the most "canonical/classical" (in your definition) one among all?

Some distributions have conjugate priors and some do not.  Is this distinction just an accident? That is, you do the math, and it works out one way or the other, but it does not really tell you anything important about the distribution except for the fact itself?  Or does the presence or absence of a conjugate prior reflect some deeper property of a distribution? Do distributions with conjugate priors share some other interesting property or properties that other distributions lack that causes those distributions, and not the others, to have a conjugate prior?


I think this folder was probably created by accident at some point, but I can't ls or cd to it to check.  Things I have tried:  ls '-F'  ls "-F"  ls \-F  ls \\\-F  ls \\-F   and the cd equivalents

This may be a simple question, but how do I use files starting with "-" with command line programs?   For example,  I am trying to use pdfgrep on a file named -2013-01-01.pdf but it complains that there are no options defined for 2, 0, 1, 3 and so on.  Changing the filename to something that does not start with "-" solves it, but this is not an option since the files aren't created by me. I simply want to check for a specific change I know is coming.


What form does the Riemann hypothesis have for a global L-function?

(I'll keep this one short)  Given a Dirichlet series  $$g(s)=\sum_{k=1}^\infty\frac{c_k}{k^s}$$  where $c_k\in\mathbb R$ and $c_k \neq 0$ (i.e., the coefficients are a sequence of arbitrary nonzero real numbers), and assuming that $g(s)$ can be analytically continued, does it follow that $g(s)$ possesses a critical strip containing its nontrivial zeroes?  If this does not generally hold, what restrictions should there be on the $c_k$ for $g(s)$ to possess a critical strip?  (My attempts at searching bring too much stuff on Riemann $\zeta$, with only a quick mention of general Dirichlet series; pointers to the literature would be appreciated.)


I'm using Windows 10 and I want to dual boot with Ubuntu 18.10. I used Rufus to make Sandisk Cruiser Blade 16GB (USB flash drive) bootable. When I successfully booted into Ubuntu 18.10 for the first time (Try Ubuntu without installing mode) and then clicked on Install Ubuntu icon on the Ubuntu desktop, the installation wizard appeared and did something, but somehow the setup was interrupted and my Asus Vivobook X510 UNR laptop rebooted. After that I couldn't boot into Ubuntu (not even try mode.) When I choose to boot using my bootable USB flash drive, a black screen appears with this error message:   Failed to open \EFI\BOOT\mmx64.efi - Not Found" Failed to load image \EFI\BOOT\mmx64.efi: Not found Failed to start MokManager: Not Found Something has gone seriously wrong: import_mok_state() failed: not found   I'm still able to boot my preinstalled Windows 10 Home, but I can't boot Ubuntu.

I tried to install Ubuntu 18.10 on my XPS 15 9570 earlier. Everything was working fine until I got to the partition selection part of the installation. That's when the installer crashed and I had to shut down my machine. I think it's because I had my SATA configuration set to RAID ON instead of AHCI, which is now fixed.  Now when I try to run the installer from my bootable USB I get the following error  Failed to open \EFI\BOOT\mmx64.efi - Not Found Failed to load image \EFI\BOOT\mmx64.efi: Not Found Failed to start MokManager: Not Fond Something has gone seriously wrong: import_mok_state() failed   Hoping someone might have some idea as to what is going on


My professor said that the main idea of finding a Jordan normal form is to find the closest 'diagonal' matrix that is similar to a given matrix that does not have  a similar matrix that is diagonal. I know that using a diagonal matrix is good for computations and simplifying powers of matrices.  But what is the potential of finding a matrix with Jordan form? what is this 'almost diagonal' matrix gives me? We learnt how to find it, without knowing what is the main idea behind it and what are the applications used with it, so I can't really understand it.

I don't claim at all to be an expert on this topic. In many (advanced) linear algebra textbooks for undergraduates, I usually find something about the "Jordan Canonical Form" of a matrix.   What is the purpose of such a form? I have taken a usual first-course in linear algebra (did another semester with Axler, but I don't claim to be an expert) and have taken abstract algebra (most familiar with group and ring theory) and have briefly skimmed through linear algebra books covering this material, but I don't quite understand the "big picture" idea, i.e., why is this useful in application? One person once told me it is the "most straightforward and useful algorithm for solving systems of linear equations, once you get beyond 3 variables or so," but maybe I'm missing something, since I usually don't see anything like what this person described to me in the linear algebra books I have. Most textbooks I've seen tend to have a more theoretical focus on this topic.  Also, any suggested texts which have good coverage on this topic would be very helpful.


I have this group $$G= \left\{ A = (a_1 ,a_2,a_3) \in GL_3(\mathbb{C}) :a_i \in \left\{\pm  \pmatrix{1 \\ 0\\ 0} , \pm  \pmatrix{0 \\ 1\\ 0} , \pm  \pmatrix{0 \\ 0\\ 1} \right\} \right\}.$$ I know that This group is an product of cyclic group (-+1) with S3, so while Iam checking the conjugacy classes to this group I found the classes that map to elements of order 2 and the diagonal matrices, but  I got stuck of classes that map to elements of order 3 , I know that their conjugate must be $\left(\begin{array}{ccc}0&*&0\\0&0&*\\*&0&0\\ \end{array}\right)$ and l know that the determinant is + or- 1 but I don’t understand why if the order of the elements is 3 then determinant is 1, and for elements with order 6 determinant is -1 ? (and why we have elements with order 6?), does it mean that there’s 2 classes from this kind of map? I’ll be thankful for help to understand my Question

I want to find the conjugacy classes of this group: $$G=\{(a_1,a_2,a_3):a_i=\pm e_j\}\subset GL_3(\mathbb C)$$ I know that $S_3$ is one of the subgroups of this group, so I can check which elements of $S_3$ continues to be conjugate in our group, I know that in $Z(G)$ there is two elements $I,-I$. I know that I have to check the diagonal matrices on which ones are conjugate, but I don't know how to finish and find the others conjugacy class of this group, and I don't Know how to find the number of the elements of the conjugacy class. I'll be thankful for help


Let $(X, \mathcal{M}, \mu)$ be a measure space with $\mu(X)<\infty$ and $f:X\to \overline{\mathbb{R}}$ be a  measurable function and $f>0$ a.e on $X$. Let $A_n\in\mathcal{M} ,\,  n=1,2,...$ and suppose that $$\lim_{n\to\infty}\int_{A_n}fd\mu=0$$. Prove $$\lim_{n \to \infty}\mu(A_n) = 0$$

Let $f:[0,1] \to \mathbb{R}$ be Lebesgue measurable with $f > 0$ a.e. Suppose that $\{E_n\}$ is a sequence of measurable sets in $[0,1]$ with the property that $\displaystyle \lim_{n \to \infty}\int_{E_n} f \,dm = 0$. Prove that $\displaystyle \lim_{n \to \infty} m(E_n) = 0$.   This question is from an old analysis qual I am studying. So far I have tried a proof by contradiction: if $\displaystyle \lim_{n \to \infty} m(E_n) \neq 0$, then there is an $\epsilon > 0$ and a subsequence $\{n_k\}$ so that $m(E_{n_k}) \ge \epsilon$ for all $k$. I am trying to somehow use this subsequence and show $\displaystyle \lim_{k \to \infty}\int_{E_{n_k}} f \,dm \neq 0$, which would give me a contradiction.  Another fact I know from my measure theory course is that, for meausurable $E \subseteq [0,1]$, the map $\displaystyle \nu(E) = \int_E f \,dm$ defines a measure on the Lebesgue measurable subsets of $[0,1]$. Will this fact be useful to me?


I'm trying to install Ubuntu Server 13.10 AMD64 x86 (The guest) on my TOSHIBA Satellite L655D-S5109 (The host).  My/the processor is AMD Turion IIP540 Dual-Core Processor 2.40GHz (64bit OS/x86) And I'm using VirtualBox 4.3.2 r90405  The problem i found is the common "this kernel requires an x86-64 cpu but only detected an i686 cpu".  Reaing on other posts in here and Stackoverflow and some other places i found out that i need the x86 virtualization ()  Checking the Oracle VM VirtualBox on the VM System tab, i found that I DO have the VT-x/AMD-V ON or activated or the checkbox checked... but i still can't install Ubuntu Server, the message still appears... what else is there to do?  Should i giveup and install a 32bit? Should the virtualization be enables on my computer (Host) BIOS or what else is there to check/verify?

I was trying to install Ubuntu 12.04 in VirtualBox 4.2.12r84980. I see    this kernel requires an x86-64 CPU, but only detects an i686 CPU, unable to boot   But I am using a 64 bit Windows 8, and trying same .iso for trying Ubuntu. Then what is the problem?


I tried to prove that if $n>2$ then $(n!)^2>n^n$ but did not managed. That is the trick to compare those as both grows rapidly? Induction seems hard: $((n+1)!)^2=(n+1)^2(n!)^2>(n+1)^2n^n$ but why $(n+1)^2n^n>(n+1)^{n+1}$? I also noted that $n^n=e^{n\ln n}$ and $n!^2=e^{2\ln n!}=e^{2\sum_{i=1}^n \ln i}$ but got stuck.

Show that if $n>2$, then $(n!)^2>n^n$.     My work: I tried to apply induction. So, at the induction step, I need to prove, $n^n>(n+1)^{n-1}$ Here, I tried to use induction again without any luck. I also took log of both sides, but I did not get anything. Please help!


When did this usage become common, especially in a sarcastic or ironic context?     Carnegie Mellon erroneously sends computer science admission letters to 800, because computers. [emphasis added]   (source for example: )

I've noticed an interesting usage where "because [noun]." is used at the end of a sentence to mean "because [...everything that word implies. Nothing more needs to be said]". It often has a wry or sarcastic tone that implies the subject considers the word to be a blanket explanation for something.   An example might be "She couldn't drag herself away from the computer because internet.", the implication being that the Internet is seductive. Another example is  where "because sex" is used to imply that a group of people have a simplistic attitude to how sex affects people's lives.  The odd grammar causes a clang in my head when I read it, but of course that is the point; the author is showing how this word will stop the conversation dead in its tracks, so it is quite effective.   Is this a new or emerging usage, or have I just started noticing it?


I want to install apps on internal sd card but instead all apps get installed on phone storage which is low in memory

I would like to know whether there is a way to tell Android to install applications on the micro SD card by default instead of having to download applications to internal memory first and then having to move them to the SD card manually.  Thanks


One of the question at HW in Number Theory was calculating $$147^{147}\mod 13$$ We didn't see much about the modular properties yet, so I am kind of stuck. Could someone give a hint or a direction how to approach it?

$$\large2017^{(2020^{2015})} \pmod{13}$$  I am practicing for my exam and I can solve almost all problem, but this type of problem is very hard to me. In this case, I have to compute this by modulo $13$.


I know that the following JavaScript code instructs the browser to insert the specified URL string into the address bar AND go there:  document.location.href = 'http://www.john-doe.com/';   However, what I want to do is to only change the URL that appears in the address bar, but don't actually go to that URL.  How can I do this?

How would I have a  action that may have some effects on the current page but would also change the URL in the browser so if the user hits reload or bookmark, then the new URL is used?    It would also be nice if the back button would reload the original URL.  I am trying to record JavaScript state in the URL.


Let me start off with these sources I have found that are not helpful to me, because they are not asking the same thing, no matter how similar it might sound:       And recently:    Essentially, these threads all suggest browser settings & adding the attribute autocomplete='off'. This is not a valid solution for me nor is it the issue that I am having. My issue is as follows:  Using Incognito Mode in Chrome:   User A clicks on "Patient Portal" to bring them to the login page. (Good) User A logs into their account by filling in their email & password. (Good) User A logs out of their account & is brought back to the Kiosk home page. (Good) User B clicks on "Patient Portal" to bring them to the login page. (Good) User B sees User A's email filled in the email field. (BAD)   User B can remove User A's email from the field & enter their own without Chrome's suggestions of previously entered emails.  It is not okay to retain a users email address on a public computer, how might I fix this issue?

One of the joys of working for a government healthcare agency is having to deal with all of the paranoia around dealing with PHI (Protected Health Information). Don't get me wrong, I'm all for doing everything possible to protect people's personal information (health, financial, surfing habits, etc.), but sometimes people get a little too jumpy.  Case in point: One of our state customers recently found out that the browser provides the handy feature to save your password. We all know that it has been there for a while and is completely optional and is up to the end user to decide whether or not it is a smart decision to use or not. However, there is a bit of an uproar at the moment and we are being demanded to find a way to disable that functionality for our site.  Question: Is there a way for a site to tell the browser not to offer to remember passwords? I've been around web development a long time but don't know that I have come across that before.  Any help is appreciated.


I came across a probability question from the interview book and does not have a solution from the top of my head. I was thinking of directly counting the number of choices for each user, but it will incur a lot of cases to discuss in separate whether the user's potential mutual best friend has already been taken or not. Can anyone give me some suggestions on how to approach this question? The question is pasted below: There are two groups of n users, A and B, and each user in A is friends with those in B and vice versa. Each user in A will randomly choose a user in B as their best friend and each user in B will randomly choose a user in A as their best friend. If two people have chosen each other, they are mutual best friends. What is the probability that there will be no mutual best friendships? Thanks!

PROBLEM STATEMENT     Given two finite sets $A$ and $B$, each containing $s \in \mathbb N$ elements, how many pairs of functions $f \colon A \rightarrow B$ and $g \colon B \rightarrow A$ are there, such that their composition $h = g \circ f$ has no fixed points?   THE ORIGIN OF THE PROBLEM     It is highly improbable that two people could happen to like each other by chance.   Which, under the following assumptions:   We are considering a group of $2n$ people with $n$ men and $n$ women; Each person likes exactly one person of the opposite sex with equal probability;   reduces to     Given two finite sets $A$ and $B$, each containing $n \in \mathbb N$ elements, and two arbitrary functions $f \colon A \rightarrow B$ and $g \colon B \rightarrow A$, what is the expected number of pairs of elements $(a \in A, b \in B)$ such that $f(a) = b$ and $g(b) = a$?   WHAT I HAVE DONE  Here I am using $E$ for expectation, $P$ for probability and $N$ for number.  $$E(\text{number of pairs}) = \sum\limits_{k=0}^n k \cdot P(\text{there are exactly }k\text{ pairs})$$  $$P(\text{there are exactly }k\text{ pairs}) = \frac {N(\text{situations with }k\text{ pairs})} {N(\text{total situations})}$$  $$N(\text{total situations}) = (n^n)^2,$$  because there are $n^n$ functions from $A$ to $B$ and the same number in the reverse direction.  $$ \begin{aligned}  N & (\text{situations with }k\text{ pairs}) = \\  & = N(\text{pairs of functions }(f \colon A \rightarrow B, g \colon B \rightarrow A) \\  & \quad \text{ whose composition has exactly }k\text{ fixed points}) = \\  & = \sum [\text{over selections of }k\text{ elements from both }A\text{ and }B] \\  & \quad N(\text{pairs of functions whose composition is identity only on the selection}) = \\  & = {\binom {n} {k}}^2 \cdot k! \cdot N(\text{pairs of functions on two sets containing } \\  & \quad s = n - k\text{ elements whose composition has no fixed points}) \end{aligned} $$  This is how I reduced the original problem to the problem in question. If the solution to that problem was $N(s)$, the answer to the original problem would be  $$E(\text{number of pairs}) = \frac {1} {(n^n)^2} \sum\limits_{k=0}^n k \cdot {\binom {n} {k}}^2 \cdot k! \cdot N(n - k)$$  WHAT I TRIED TO DO  Approach: fix $g$, count $f$s.  $$ \begin{multline} N(s) = \sum [\text{over all functions }g \colon B \rightarrow A] \\ N(\text{functions }f \colon A \rightarrow B\text{ such that the composition }h = g \circ f \\ \text{ has no fixed points}) \end{multline} $$  Problem: all such $f$s have to send every $a$ to anywhere but $g^{-1}(a)$. Therefore, there are $\prod\limits_{a \in A} (n - \left|g^{-1}(a)\right|)$ such functions. The sets $\left\{g^{-1}(a)\right\}_{a \in A}$ form a partition of $B$. The obvious next idea is to classify all $g$s based on that partition, but the formulas start to get really scary.  UPD: I wrote a simulation that actually counted directly the expectation for $n=1..5$ (the $O(n\cdot(n^n)^2)$ approach). The expected value is always exactly 1. I have no idea how to interpret that, given the crazy formula for expectation.  I would mostly appreciate an idea for an approach, not a complete solution.


How am I able to find how many involutions are in $S_n$ for any nonnegative integer $n$? Let's say for $S_4$. Is there an equation or anything that allows me to find this with ease?

I have a set with $N$ members $\{1,2, \dots, N\}$. I would like to know number of set partitions in which each subset is either of size $1$ or $2$, i.e., cardinality of each subset in the partition is maximum $2$. For example with $N=3$, we have the set partitions of maximum size $2$ are $\{1,2,3\}, \{(1,2),3)\}, \{1,(2,3)\}, \{(1,3),2\}$. However I am not interested in $\{(1,2,3)\}$ since it is of length $3$. Kindly tell me number of such set partitions for a set with $N$ members.


I am on Ubuntu, I have 2 external hard drives, of of them is an SSD. The HDD is from a laptop with windows 10 on it, the SSD is completely empty, I want to use it to copy everything on the HDD to the SSD. I'm using a powered usb 3.0 hub with 2 sata to USB 3.0 cables to connect the drives to  my computer.   I was going to this with dd but I realized windows has many partitions, sdb1(C:\ drive), sdb2(EFI system partition), sdb3 (Microsoft reserved partions), sdb4(basic data partition). How can I copy all of them to the SSD using dd?

I am attempting to clone multiple partitions with either  or dd without cloning the whole drive which consists of:  A boot partition A home partition  Seen below is the original installation on a 128GB SSD, which I successfully cloned to a larger 250GB. This as a backup that I would later try to resize and shrink down.  Below is a photo of a working clone of the operating system, which is now about 41 gigs in size total after being resized with Gparted.  I have tried to clone these partitions to my 64GB USB disk as a working portable backup, but have ran into some issues. I have tried using: sudo -s dd if=/dev/sdb of=/dev/sdc & pid=$! while kill -USR1 $pid; do sleep 1; done  This bit for bit cloning method tried to copy the unallocated space on the input drive, which obviously won't work because the output disk is much smaller. In a second attempt I was able create a partition table on the destination disk that matched the source's sizes. I then tried to use boot repair and got  Moving onto to  options; normally a disk to disk would be my choice, but since the destination drive is smaller than the source,  will not allow this. I do see an option to copy ONE partition at a time using the disk to disk option, but do not see how I might clone all three at once. I know there is an option to do this with saving as image but I want the USB to be bootable. One way I can think of making this work would be to make an image of the partitions I want to clone using disk to image, then restoring the image to the 64GB USB disk later, but after trying this I ran into more errors. After making an image of /dev/sdb/ I attempted to restore the file but got this error about /dev/sdb2/ missing:  (/dev/sdb is the target for this session) So perhaps my image was OK, but it didn't properly read /dev/sdb2/ so I checked it with Gparted again and saw this following here:  I checked with Synaptic Package Manager to see, and I already have e2fsprogs v1.42.9-3 installed. So I did some reading and tried the following solutions that have worked for other people: sudo fsck.ext4 -f /dev/sda6 sudo touch /forcefsck Sudo reboot  this seemed to work temporarily, as after another reboot or two, the problem still persists. I am assuming now that during the device to image process in Clonezilla that my /dev/sd2/ was not read properly, as I can not even access this partition in Nautilus or Gparted. I am thinking that is may have been caused by the re-sizing of the drive, but can not be sure, as it will still allow me to boot to this installation. I think I can actually clone these two partitions to image, and then restore them but I need to address this problem of:  The following list of software packages is required for ext4 file system support: e2fsprogs v1.41+.  Could this have come from re-sizing the partition? If so, how come I am able to boot to this installation if it can't be read?


I'm running into troubles when mixing Babel French and tikz-qtree. Here is a minimal non-working example :  \documentclass[11pt,a4paper]{article} \usepackage[utf8]{inputenc} \usepackage[T1]{fontenc} \usepackage[french]{babel} \usepackage{tikz,tikz-qtree} \usetikzlibrary{arrows,arrows.meta}  \begin{document}      \begin{tikzpicture}     \Tree [.CP [.NP \node(wh){what}; ]     [.C$'$ [.I did ]     [.\node[draw]{IP};     [.NP [.Det the ] [.N cat ] ]     [.VP [.V sit ]     [.PP [.P on ]     [.\node[draw]{NP};     [.NP [.Det a ] [.N book ] ]     [.PP [.P about ] [.NP \node(t){$t$}; ] ] ] ] ] ] ] ]     \draw[semithick,->] (t)..controls +(south west:5) and +(south:5)..(wh);     \end{tikzpicture}  \end{document}   The error is :  Runaway argument? (wh){what}; ] [.C$'$ [.I did ] [.\node [draw]{IP}; [.NP [.Det the ] [\ETC. ! Paragraph ended before \@@@@litlabel was complete. <to be read again>                     \par  l.22    Removing the Babel declaration, or switching the french option to german, allow the code to compile. Spanish also causes troubles, with a different error :  ! Argument of \language@active@arg> has an extra }. <inserted text>                  \par  l.20    \draw[semithick,->]                           (t)..controls +(south west:5) and +(south:5)..(wh);   I've read  and tried to apply the , with no success (but I had no more success with the code given in this thread that caused troubles : may be I'm doing things the wrong way...).  Could someone help ? Thanks a lot in advance.  1st edit : I've just realized that  offers a solution. Putting \shorthandoff{;} at the start of the tikzpicture environment allows the document to compile. It's quite strange as the question is quite old now (almost 4 years) and I've recently updated my TeXlive distribution to the 2016 version (it was yesterday ! so it is supposed to be up to date !).

In my preamble, you'll find:  \renewcommand{\baselinestretch}{1} \renewcommand{\familydefault}{\sfdefault} \usepackage[sfmath]{kpfonts} \usepackage[mathrmOrig]{sfmath} \usepackage{amsmath} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{animate} \usepackage{anysize} \usepackage{arcs} \usepackage{array} \usepackage[scale=0]{background} \usepackage{blindtext} \usepackage{calc} \usepackage{cancel} \usepackage{chngcntr} \usepackage{CJK} \usepackage{CJKspace} \usepackage{CJKpunct} \usepackage{colortbl} \usepackage{enumitem} \usepackage{epstopdf} \usepackage{etoolbox} \usepackage{fancybox} \usepackage{fancyhdr} \usepackage{float} \usepackage{framed} \usepackage{graphicx} \usepackage{hyphenat} \usepackage{ifthen} \usepackage{latexsym} \usepackage{lmodern} \usepackage{multicol} \usepackage{multirow} \usepackage{mwe} \usepackage{pgffor} \usepackage{rotating} \usepackage{tabularx} \usepackage{textcomp} \usepackage{tgheros,tgtermes,tgcursor} \usepackage{tikz} \usepackage{times} \usepackage{tipa} \usepackage{varwidth} \usepackage{wasysym} \usepackage{wboiboites} \usepackage[abs]{overpic} \usepackage[breaklinks,colorlinks=true,linkcolor=red,citecolor=red, urlcolor=blue]{hyperref} \usepackage[framemethod=TikZ]{mdframed} \usepackage[breakable, theorems, skins]{tcolorbox,empheq} \usepackage[default]{gillius} \usepackage[document]{ragged2e} \usepackage[latin1]{inputenc} \usepackage[spanish]{babel} \usepackage[T1]{fontenc} \usepackage[total={18.59cm,26.5cm},left=1.5cm,top=2.5cm]{geometry} \usetikzlibrary{matrix,arrows, positioning,shadows,shadings,backgrounds,calc, shapes, tikzmark} \usetikzlibrary{shadows.blur} \usetikzlibrary{shapes.symbols} \usetikzlibrary{patterns,fadings} \tcbuselibrary{skins,breakable,listings,theorems}    I'm trying to draw an arrow for X axis and Y axis.   \begin{tikzpicture} \draw[yellow!10, fill=blue!5](-1, -1) rectangle (7, 5); \draw[dotted] (-0.75,-0.75) grid (6.75,4.75); \node[below] at (-0.25,0){$O$}; \draw[->,black, thick] (-0.75,0)--(6.75,0); \end{tikzpicture}   But I get this error:    Additionally, if I remove -> from the options of \draw the tikz picture compiles normally.


I am trying to create my own BibTeX file and use it in my TeX file. I am using Texmaker as the editor.  This is the content of my BibTeX file as of for now:  @ARTICLE{introtobiorec, author = {Anil K. Jain and Arun Ross and Salil Prabhakar}, title = {An introduction to biometric recognition}, journal = {IEEE Trans. on Circuits and Systems for Video Technology}, year = {2004}, volume = {14}, pages = {4--20} }   I have included   \usepackage{cite}   I also tried using  \usepackage{natbib}   I include the BibTeX file (MyBibFile.bib) as follows:  \bibliographystyle{style} \bibliography{MyBibFile}   It does not really throw any error but it does not work.  Any help would be appreciated.

I'm having some problems with my bibliography in Texmaker. My code is:  \documentclass[11pt, a4paper]{article} \usepackage{graphicx} \usepackage{amsmath} \usepackage{natbib} \usepackage[utf8]{inputenc}     \usepackage{natbib} \usepackage[usenames,dvipsnames]{xcolor} \usepackage[left=2cm,right=2cm,top=2cm,bottom=2cm]{geometry} \begin{document}  ....  \cite{Johnson} \bibliographystyle{plain} \bibliography{mybib}  \end{document}   I also created a new file (File > New) that I saved as mybib.bib:  @Article{Johnson, author = {Edgar G. Johnson and Alfred O. Nier}, title = {Angular Aberrations in Sector Shaped Electromagnetic Lenses for Focusing Beams of  Charged Particles}, journal = {Physical Review}, year = {1953}, volume = {91}, number = {1}, }  @phdthesis{Zoran, author = {Zoran Racic}, title = {\'Etude et essais du spectromÃ¨tre Ã  plasma {DYMIO} de la  mission {MARS 96}}, publisher = {UniversitÃ© Pierre et Marie Curie}, year = {1996} }   When I compile my .tex file, I only have a [?] appearing.  Could you tell me what my mistake is?


Consider a cylinder on top of inclined plane with angle x = 30 degrees. Now let the coefficient of friction is tan 30. What will be the motion of the body. It seems that either of the two will occur (assume perfectly leveled plane)   The friction is up the plane and provides angular acceleration however the net force is zero. And the kinetic energy of the body keeps on increasing constantly or does froction immediately change direction and body starts rolling down the plane ?  In either case it seems somehow the laws of physics are failing only if we assume normal reaction to pass through some other point other than centre of mass only then it makes sense?  I guess my confusion is whether the friction akes up its maximum value or does it take smaller value so as to meet no slip condition

Consider an inclined plane with angle $x$. Now put a cylinder on top of it and consider three different cases.   A the limiting frictional force $f$ is greater than $mg\sin(x)$ where $m$ is the mass of cylinder. B the limiting friction $f$ is exactly equal to $mg\sin(x)$ C it is less than $mg\sin(x)$.   What will happen in each case?  In A and B I suppose $f$ will provide torque and then friction will change direction to oppose the angular velocity maybe.  In C it will start moving and then provide torque but the friction should vanish although it stays there and apparently it may or may not cause slipping. What is meaning of slipping?  I am not sure about these cases. Can someone explain. I just need physical intuitive explanation.


Is it possible to use a single mac for multiple users as if they were working on their own mac?  So would it be possible to connect for example two screens, two keyboards (bluetooth or not) and two mouses (bluetooth or not) and both be working like you have your own Mac? If it's not possible with macOS, is it possible by using virtual machine software and run two separate macOS installations? Is there a limit on how many users? Could you change the number of "virtual machines" or users easily?

Using Linux you can connect multiple keyboards, monitors etc. and use one CPU with multiple users, each logged in to their own home environment.  See what I mean here:   Is there any way to achieve the same on OS X?  Clarification: All viewers seem to understand this question as: remote logon, or remote X.  This is NOT the question.  I hope the following diagram will clarify:  |-------| |single | |MAC OS | |box    | |-------|   |_Monitor1__keyb1__Mouse1__user1   |   |   |_Monitor2__keyb2__Mouse2__user2   Remark: It seems X11 is available on OS X. I haven't seen any practical examples yet. Remote X seems possible using X11. Not sure at all about multiseat capability with additional mouse and keyb..  Perhaps this may be 'a' way to go?


After windows 10 has perform an update I can't login to windows. (The computer is not mine, it is my friend computer)  I have used a PIN code to login to windows, and after the update it no longer accept the PIN code.  I don't know the email address nor the password.  I already tried to restart with command prompt, to enabled administrator.  Nothing worked, i always asked to provide a password that i don't have.  I don't want to erase and reinstall again.  Any suggestions?

I got a brand new Windows 7 machine, installed the operating system, created one account and forgot its password. What can I do?  There is no external CD, the operating system is loaded from somewhere inside the machine.  I already tried to remember passwords and tried all candidates with all possible combinations of caps lock, num lock etc.


For example, if I am using a longbow, and my party is ~50ft in front of me, and I have made no actions other then getting up to a high point, am I able to shoot with advantage, and if so, can I use the hide action?   If you look at a question such as , it talks about specific exceptions to how being hidden is being unseen and unheard, and I am not sure if this is an exception or not.

I always assumed you needed to be hidden to get advantage when attacking/disadvantage when being attacked, but after looking at the rules I'm fairly certain this is not the case.  There's a chance I'm reading into it incorrectly, though.  For example, assume I have  cast on myself.  No matter how many attacks I make, or whether or not my enemy knows where I am (but can't actually see me), do I still have advantage to hit and they have disadvantage to hit me?  I think that's what's accurate.  This would implicate that "Hidden" means "Enemies don't know where you are and think you could be anywhere", which changes my prior understanding of hiding drastically.  Am I correct on this?


If I read bytes from a file into a byte[] I see that FileInputStream performance worse when the array is around 1 MB compared to 128 KB. On the 2 workstations I have tested it is almost twice as fast with 128 KB. Why is that?  import java.io.*;  public class ReadFileInChuncks  {     public static void main(String[] args) throws IOException      {         byte[] buffer1 = new byte[1024*128];         byte[] buffer2 = new byte[1024*1024];          String path = "some 1 gb big file";          readFileInChuncks(path, buffer1, false);          readFileInChuncks(path, buffer1, true);         readFileInChuncks(path, buffer2, true);         readFileInChuncks(path, buffer1, true);         readFileInChuncks(path, buffer2, true);     }      public static void readFileInChuncks(String path, byte[] buffer, boolean report) throws IOException     {         long t = System.currentTimeMillis();          InputStream is = new FileInputStream(path);         while ((readToArray(is, buffer)) != 0) {}          if (report)             System.out.println((System.currentTimeMillis()-t) + " ms");     }      public static int readToArray(InputStream is, byte[] buffer) throws IOException     {         int index = 0;         while (index != buffer.length)         {             int read = is.read(buffer, index, buffer.length - index);             if (read == -1)                 break;             index += read;         }         return index;     } }   outputs   422 ms  717 ms  422 ms  718 ms   Notice this is a redefinition of an already posted question. The other was polluted with unrelated discussions. I will mark the other for deletion.  Edit: Duplicate, really? I sure could make some better code to proof my point, but  does not answer my question  Edit2: I ran the test with every buffer between 5 KB and 1000 KB on Win7 / JRE 1.8.0_25 and the bad performance starts at precis 508 KB and all subsequent. Sorry for the bad diagram legions, x is buffer size, y is milliseconds

How do you write (and run) a correct micro-benchmark in Java?  I'm looking for some code samples and comments illustrating various things to think about.  Example: Should the benchmark measure time/iteration or iterations/time, and why?  Related:


Without using Cauchy's or Sylow's theorems , can we give a proof of the result that "If $ p,q$ are primes such that $p>q$ and $q$ does not divide $p-1$ , then any group of order $pq$ is cyclic " ?

If $|G| = pq$,  $p,q$ primes, $p \gt q, q \nmid p-1 $, then how do I prove $G$ is cyclic without using Sylow's theorems?


I have to sort the given array on date key in PHP. I have tried it using array_multisort but not able to sort it. which one is more appropriate usort or array_multisort?  Array (     [165953] => Array         (             [0] => Array                 (                     [wallet_transaction_id] => 165953                     [wallet_currency_id] => 2                     [description] => updating SC Dollars by 100.00 from PSM product transaction.                     [amount] => 100.00                     [date] => 2013-11-13 08:08:05                 )              [1] => Array                 (                     [wallet_transaction_id] => 165953                     [wallet_currency_id] => 3                     [description] => updating Spy Points by 50.00 from PSM product transaction.                     [amount] => 50.00                     [date] => 2013-11-13 06:08:05                 )          )      [165952] => Array         (             [0] => Array                 (                     [wallet_transaction_id] => 165952                     [wallet_currency_id] => 2                     [description] => updating SC Dollars by 100.00 from PSM product transaction.                     [amount] => 100.00                     [date] => 2013-11-13 05:02:11                 )              [1] => Array                 (                     [wallet_transaction_id] => 165952                     [wallet_currency_id] => 3                     [description] => updating Spy Points by 50.00 from PSM product transaction.                     [amount] => 50.00                     [date] => 2013-11-13 08:02:11                 )          ) )

I have CSV data loaded into a multidimensional array. In this way each "row" is a record and each "column" contains the same type of data.  I am using the function below to load my CSV file.  function f_parse_csv($file, $longest, $delimiter) {   $mdarray = array();   $file    = fopen($file, "r");   while ($line = fgetcsv($file, $longest, $delimiter))   {     array_push($mdarray, $line);   }   fclose($file);   return $mdarray; }   I need to be able to specify a column to sort so that it rearranges the rows.  One of the columns contains date information in the format of Y-m-d H:i:s and I would like to be able to sort with the most recent date being the first row.


I have an Ubuntu 9.04 PC behind a corporate firewall and proxy server.  This requires that in order to get update-manager to fetch and apply updates, I must set the proxy and authentication settings in the Synaptic network configuration.  Once done, I can check for updates and things work smoothly (except I don't get popup notifications of new updates, must manually check periodically).  However, distribution updates just don't show up in update-manager, such as the newly released 9.10 Karmic Koala.  I had the same issue in upgrading 8.10 to 9.04 and solved it by downloading and .  What do I need to do to upgrade to 9.10 using the standard update-manager UI?

I've been trying to upgrade my installation of Ubuntu 9.04 to 9.10, but all of the instructions I've found haven't been helping. They mostly say to run the update manager and it'll tell you that there's a new distribution ready. Well, mine doesn't say that.  Things I've run or checked:   update-manager -d says:     Your system is up-to-date   The package information was last updated less than one hour ago.  I've set it to get all new distributions, not just LTS  $ cat /etc/update-manager/release-upgrades [DEFAULT] # default prompting behavior, valid options: #  never  - never prompt for a new distribution version #  normal - prompt if a new version of the distribution is available #  lts    - prompt only if a LTS version of the distribution is available Prompt=normal  I'm definitely running 9.04  $ lsb_release -r Distributor ID: Ubuntu Description:    Ubuntu 9.04 Release:        9.04 Codename:       jaunty  Even running the release upgrade from console doesn't help:  $ sudo do-release-upgrade  Checking for a new ubuntu release No new release found    This is running from behind a proxy, but I've set it up such that the regular upgrades and apt-get etc doesn't complain. (export http_proxy=http://myuser:mypass@myserver:8080/)  Could you think of anything else which might be stopping me from upgrading?


I want to store arabic in mysql database but when I execute query it convert arabic to some numbers like u0645u0631u062du0628u0627  when I print this query in which $datas='hello'  insert into taxi_notification(user_id,message,datetime,type)      values(".$user_id.",'".$datas."',NOW(),'".$type."');   it converts it to   insert into taxi_notification(user_id,message,datetime,type)      values(1965,'\u0645\u0631\u062d\u0628\u0627',NOW(),'admin_notification')   I want to store Arabic string as it display in browser

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1.  Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur?  This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2.


How can I delete lines in a file until it matches a string line pattern?  cat test.txt The first line The second line The third line The fourth line pen test/ut The sixth line The seventh line   I would like to use shell/python script to remove all the lines from the above file until it matches the file string pattern "pen test"  Expected output: The file "test.txt" should have only these lines after removing above lines:  The sixth line The seventh line

Input file1 is:  dog 123 4335 cat 13123 23424  deer 2131 213132 bear 2313 21313   I give the match the  pattern from in other file ( like dog 123 4335 from   file2).  I match the pattern of the line is dog 123 4335 and after printing all lines without match line my output is:   cat 13123 23424 deer 2131 213132 bear 2313 21313   If only use without address of line only use the pattern, for example 1s how to  match and  print the lines?


I bought new notebook (Acer Aspire F15 / F5-573-56GH) with Win 10 (64b, 8GB RAM, Intel I5), where just after clicking icon (Chrome, FF, File manager, everything) it appeared (the app or app init screen - like Gimp) almost at that moment.  After hours messing up with installation of Kubuntu 16.04 (which didn't work with UEFI, I had to set BIOS Legacy) to replace Win 10, I have to wait after click on any app launcher, and wait about 3sec. before it could be used. Is there any way to speed up apps launch? I think there must be some delay set in system?

Is it possible to "preload"(actually not preload, but kinda emulate the startup) e.g. nautilus (or firefox) startup at login, so the first time I launch it myself it launches faster? Probably to start it on another desktop and close after some seconds?


I just flagged a question as a duplicate. A few minutes later the question was closed as a duplicate with only a much higher rep user's name and Community (two users total) in the close message.  Why doesn't my name appear in the close message since I was the first to flag it?

Earlier today, I marked a question on Stack Overflow as a duplicate. Then I waited about 5-10 minutes and it showed 5 people. However, my name wasn't included.  I also remember that the question that was linked on top was the same question that I selected.  Now I'm not trying to ask for the "spotlight" but I just want to know how does this naming system work? Do they go in order or do they go by reputation?


Can somebody please explain why $n^2+4$ is never divisible by $3$?  I know there is an example with $n^2+1$, however a $4$ can be broken down to $3+1$, and factor out a three, which would be divisible by $4$.

I need to show the following:  For any integer $x$, $x^2 + 4$ is not divisible by $3$.    I was trying proof by contraposition, but I do not believe that is the most efficient way to go about this.  Can anybody point me in the right direction, please?


I baked individual lemon soufflés that collapsed before I removed them from the oven. Please advise me as to what I need to do to keep these items from collapsing. Thanks.

I am trying to make a cheese soufflé to surprise my girlfriend on her birthday (24 Jan). After several cooking trials, I still face a key problem: my soufflé collapsed after baking for 25-30 minutes.   What did I do wrong? Here are the steps to the recipe;   boil equipment grease butter to the renakin, place into the freezer separate egg whites (no yolk mixed) add a little salt to egg whites add a little sugar to egg whites  using a hand mixer, whip the egg whites adding more sugar during whip melt 40g butter (100C) Whisk 40g all purpose flour into melted butter pour 250g milk slowly and whisk util it mixed wait until it cools down re-grease butter to the renakin, place into the freezer beat the egg yolks to a creamy consistency, then pour into the milk mixture add 1/3 of the mixture to the base, continue to add the whites folding very gently. Preheat oven to 200C (5-10 minutes) pour the mixture into the renakin add the cheese on the top bake at 170'C (with heat select="lower")   After about 25-30 minutes and a 2cm rise, the soufflé collapses prior to removing from oven.    updated 19 Jan Evening :  I do   buy better hand mixer use more flour (50g) move egg whites whipping process to last steps reduce whipping time to 5 minutes bake with heat select="lower" about 15min after that change to "upper and lower" sit in front of oven and see the soufflé every moment.   result:   at 20mins: the soufflé raise about 3.5 to 4cm (from 5cm height renakin) around 25mins: it collapse about 0.5cm, so I immediately remove it from oven (T-T) after than it collapse very fast. (I guess it is common)   Thank you very much @jefromi and @KatieK for your comments and links. I plan to buy oven thermometer this morning because I have no it yet.     updated 21 Jan Lunch :  Yesterday I found problem on the oven temperature. When I set temperature to 170 C, real temperature is 150C or below (because it keep going down). So today I try to keep in range of 160-200C and no collapses now.   Thanks you very much to everybody again for kindly help.


I've done the Blood on the Ice and Morning Never Comes quests and I've helped citizens and stuff but I still can't buy Hjerim.  I have an Xbox 360 so I can't use console commands but my brother's profile that is on the same Xbox got the house! I really need the house, it's perfect for me. Why can't I buy it?

I've finished the Stormcloak storyline, and now cannot become a Thane of Windhelm without buying Hjerim. The Steward keeps saying something has happened and he can't sell it right now.  What the heck am I missing? I've been doing every random little quest from people in town I can find, hoping to unlock the house. I'm well over the 5/5 requirement of helping people.  Any ideas?


Does there exist a function from $(0,1)$ to $(0,1]$ both one-to-one and onto, not necessarily continuous?   I couldn't think of any. Any help would be appreciated!  Thanks,

How to define a bijection between $(0,1)$ and $(0,1]$?   Or any other open and closed intervals?   If the intervals are both open like $(-1,2)\text{ and }(-5,4)$ I do a cheap trick (don't know if that's how you're supposed to do it): I make a function $f : (-1, 2)\rightarrow (-5, 4)$ of the form $f(x)=mx+b$ by \begin{align*} -5 = f(-1) &= m(-1)+b \\ 4 = f(2) &= m(2) + b \end{align*} Solving for $m$ and $b$ I find $m=3\text{ and }b=-2$ so then $f(x)=3x-2.$  Then I show that $f$ is a bijection by showing that it is injective and surjective.


is there a way to omit automatic \n after 'print' in python 3.x? i want my output something like this:-  2 2 2 4 4 8 8 32   my code is like this:-  a,b=1,2 while b<10:     print (str(b)+' '+str(b*a))     a,b=b,b*a   but i want my code to be like this to print the same thing:-  a,b=1,2 while b<10:     print (str(b))     a,b=b,b*a     print (str(b))   but its printing this:-  2 2 2 4 4 8 8 32   please help me out i am a newcomer in programming and python is my first language. Thank you!

I'd like to do it in Python. What I'd like to do in this example in C: #include <stdio.h>  int main() {     int i;     for (i=0; i<10; i++) printf(".");     return 0; }  Output: ..........  In Python: >>> for i in range(10): print('.') . . . . . . . . . . >>> print('.', '.', '.', '.', '.', '.', '.', '.', '.', '.') . . . . . . . . . .  In Python print will add a \n or space, how can I avoid that? Now, it's just an example, don't tell me I can first build a string then print it. I'd like to know how to "append" strings to stdout.


I have a homework question that plays off my las question about the characteristic function $\chi_A(x)$.  It is:  Prove that there is a function $f$ that gives a one-to-one correspondence between $\mathcal{P}(X)$ and $2^X$.  Here the power set $\mathcal{P}(X)=\{A|A\subseteq{X}\}$ and $2^X$ is the set of all functions that map elements into the set $\{0,1\}$ Now i know that $|\mathcal{P}(X)|=2^{|X|}$, but the hint in the example mentions this:  "Now let us define a function $f$ on $\mathcal{P}(X)$ into $2^X$ by taking as the image a subset $A$ of $X$ the characteristic function of $A$," so then this mapping looks like this  $$f:\mathcal{P}(X)\rightarrow{2^X}$$ $$f(A)=\chi_A{x}$$  From here I must show injectivity and surjectivity.  So $$f(A)=f(B)\Rightarrow{A=B}$$  So by the definition of the characteristic function we can show that injectivity holds since if $$x\in{A}, \chi_A(x)=1=\chi_B(x) \text{ if } x\in{B}$$ and $$x\in{X-A}, \chi_A(x)=0=\chi_B(x) \text{ if } x\in{X-B}$$ But how do we create a surjectivity argument?

How can I formalize that the function $$f:\mathcal{P}(A)\to(A\to \{0,1\})$$ is bijective? It seems clear to me but I don't know how to write a proof. Thanks in advance.


I wrote this custom environment to save time when typing:  \newenvironment{equations}     {\begin{equation}\begin{aligned}}     {\end{aligned}\end{equation}}   However, it produces a strange indentation in the text that follows.  Directly writing  \begin{equation}     \begin{aligned}      things     \end{aligned} \end{equation}   does not give any problem.  What is the problem?

If I create a custom environment based on the equation environment, I get a spacing issue: the next line of text after my environment closes doesn't start on the left margin.  Example code:  \documentclass{article} \begin{document} \newenvironment{myenv}{\begin{equation}}{\end{equation}} \noindent $| \leftarrow$ this is the left margin. \begin{myenv} e ^{i \pi} + 1 = 0 \end{myenv} $| \leftarrow$ this isn't the left margin. \end{document}   Output:    Removing the newline after \end{myenv} solves the spacing problem, but the resulting code is not readable.  Of course, in this example I could just use the equation environment itself. My real issue involves a more complex custom environment that suffers from the same problem, and which also includes an equation environment within it.


Recently, at McCain's funeral Obama said:     "After all, what better way to have the last laugh than to make George and I say nice things about him to a national audience."   Is it "George and I" or "George and me"?

When the phrase is used as an object, why so many native speakers are saying "you and I" instead of "you and me"? I'm not a native speaker but I thought "you and me" is correct. Not sure if this falls into the same category, but "Just between you and me" sounds more natural than "Just between you and I".


I have 2 classes in my project  First class contains all the webelements  Second one for method where i am using this elements  package facebook;  import org.openqa.selenium.By; import org.openqa.selenium.WebDriver; import org.openqa.selenium.WebElement;  public class webelement {       private static WebElement element;       public static WebElement firstname(WebDriver driver) {         driver.findElement(By.xpath("//input[@name='firstname']"));         return element;      }     public static WebElement lastname(WebDriver driver)     {         driver.findElement(By.xpath("//input[@name='lastname']"));         return element;     }     public static WebElement email(WebDriver driver)     {         driver.findElement(By.xpath("//input[@name='reg_email__']"));         return element;     }     public static WebElement newpassword(WebDriver driver)     {         driver.findElement(By.xpath("//input[@name='reg_passwd__']"));         return element;     }     public static WebElement day(WebDriver driver)     {         driver.findElement(By.xpath("//select[@name='birthday_day']"));         return element;     }      public static WebElement month(WebDriver driver)     {         driver.findElement(By.xpath("//select[@name='birthday_month']"));         return element;      }     public static WebElement year(WebDriver driver)     {         driver.findElement(By.xpath("//select[@name='birthday_year']"));         return element;      }     public static WebElement sex(WebDriver driver)     {     driver.findElement(By.xpath("(//input[@name='sex'])[2]"));     return element;      }      public static WebElement signup(WebDriver driver) {         driver.findElement(By.xpath("//button[@name='websubmit']"));         return element;     }     }   And this is my second class where i am using this elements  package facebook; import java.util.concurrent.TimeUnit;  import org.openqa.selenium.WebDriver; import org.openqa.selenium.chrome.ChromeDriver; import org.openqa.selenium.firefox.FirefoxDriver; import org.openqa.selenium.support.ui.Select; import org.testng.annotations.Test;  import facebook.facebook; public class signup {     static WebDriver driver;     @Test     public void login()      {         System.setProperty("webdriver.chrome.driver","C:\\Users\\5558\\eclipse-workspace\\chromedriver.exe");         driver=new ChromeDriver();         driver.get("https://www.facebook.com");         driver.manage().timeouts().implicitlyWait(2000, TimeUnit.MILLISECONDS);         driver.manage().window().maximize();         webelement ele = new webelement();         ele.firstname(driver).sendKeys("dixit");          ele.lastname(driver).sendKeys("jani");         ele.email(driver).sendKeys("test@gmail.com");          ele.newpassword(driver).sendKeys("dixit1234");          Select day = new Select(ele.day(driver));          day.selectByIndex(24);          Select month = new Select(ele.month(driver));          month.selectByVisibleText("jul");          Select year = new Select(webelement.year(driver));         year.selectByVisibleText("1997");         ele.sex(driver).click();          ele.signup(driver).click();         driver.close();         }   }

I am getting java.lang.NullPointerException while executing my test case , I am using Page Object Modle with PageFactory ,following are the code snippets  LoginPageObjec.java  public class LoginPageObjects {      @FindBy(xpath=".//*[@id='userName']")     private WebElement email;      @FindBy(xpath=".//*[@id='password']")     private WebElement password;      @FindBy(xpath=".//*[@id='loginFormSubmit']")     private WebElement loginBtn;      public void EnterUserName(String userName)     {         email.sendKeys(userName);     }      public void EnterPassword(String pass)     {         password.sendKeys(pass);     }      public void clickLogin()     {         loginBtn.click();     }   }   LoginTC.java  public class LoginTC extends BasePage{     private WebDriver driver;      @Test     public void login()     {         LoginPageObjects loginPage = PageFactory.initElements(driver, LoginPageObjects.class);         loginPage.EnterUserName("test.hr@domin.com.pk");         loginPage.EnterPassword("test");         loginPage.clickLogin();     } public void login1()         {             LoginPageObjects loginPage = PageFactory.initElements(driver, LoginPageObjects.class);             loginPage.EnterUserName("test.hr@domin.com.pk");             loginPage.EnterPassword("test");             loginPage.clickLogin();         }  }   BasePage.java  public class BasePage {     private WebDriver driver;      @BeforeMethod       public void initializeBrowser() {      driver=new FirefoxDriver();      driver.navigate().to("https://nexthrm-dev.vteamslabs.com/");      driver.manage().window().maximize();      }     @AfterMethod     public void closeBrowser()     {         driver.close();     }  }   I've extended BasePage class to utilize the (initialBrowser & closeBrowser) functions in my test case but its producing nullpointer exception if I copy both of the functions (initialBrowser & closeBrowser) into my LoginTC (testcase class) it works like charm but I dont want this redundant code i.e((initialBrowser & closeBrowser) for all my testcases class could anyone explain why I am getting nullpointer exception


I'm pretty new to Java, so forgive me if this seems like a dumb question.   I have 3 classes, one of the being the main class.  Class 1 - class accounts. Just contains empty variables/objects  String firstName; int age;     Class 2 - class random. Contains an array of many names, and contains methods to randomly pick a name and to randomly pick an age:  String Names[] = {"Sophia", .....,  "Sasha", "James"}; // About a 100 names  public void nameRandom(String name) {     name = Names[rand.nextInt(Names.length)]; } public void ageRandom(int age){         age = rand.nextInt(64)+19; }     Finally, Class 3, the main class ('howManyAccounts' is an integer that is obtained through scanner):  Account[] accounts = new Account[howManyAccounts];   for (int i = 0; i < accounts.length; i++){               accounts[i] = new Account();                 random.nameRandom(accounts[i].firstName);     random.ageRandom(accounts[i].age);           }  System.out.println("NAME" + "          " + "AGE"); System.out.println("");  for (int x = 0; x < accounts.length; x++){           System.out.println(accounts[x].firstName + "          " + accounts[x].age); }

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


can i use fonts from google fonts for commercial use? like logo design or flyer or brochure,etc  i have already entered the page named "Open Font License web version" but i still can't understand if i can use these fonts for other commercial designs like logos and flyer and social media designs.  i have seen some questions here but it's old and the license might be change, so i put another question.

I want to create a logo for a contest, the winner will be paid and the winning logo will be the institutional logo of an academic entity, so I need a font which can be used freely or at a cheap cost for commercial purposes.  I see that Google Fonts are delivered as "free fonts" for websites:  May I use them freely for graphic design products (a logo in particular) as well?


I have a module where I try to catch an url to use a specific function.  function my_module_menu(){     $items['beneficiaire/commande'] = array(         'page callback' => 'test_view',     );     return $items; }  function test_view(){     var_dump('test_view');     exit(); }   Unfortunately, when I call beneficiaire/commande nothing append. I know Drupal go through this hook because when I do  function my_module_menu(){     die('poc'); }   I see 'poc'.

What are the fundamentals of implementing hook_menu()?  I would like to see the basics covered in a single question, to avoid having to answer the same similar but different questions over and over.


Is there way to automatically calculate amount of figures, tables and appendices?  I found a way to see what pages have figures( ), but how to calculate the amount.

I need to put some formal statistics on the document itself somewhere in the middle, like "This document contains XXX figures and YYY tables (and may be even ZZZ formulas and PPP theorems)". Is there a common way to output the final value of some counter in the middle of the document?  Edited after answering: I have asked a more specific question before, "How to output the number of bibliographic entries referenced in the document?", which is now deleted because the answer to this one covers also this case.  For the reference, some useful counters, which can be used with totcount:   page - page count enumiv - bibliography entries count figure - figures count table - tables count


I read most of the questions about an and a here, but still I'm not quite sure since I found that uniform should be "prefixed" with a instead of an (read in a comment here). So I totally lost the string here.     A US navy aircraft is helping with the search for debris, he says.   Is this correct or should it be An US navy aircraft...?

Which indefinite article should precede hour — a or an?        an hour     a hour      Does the usage of an vs a depend on the pronunciation — a history, a hobby, but an hour, an honor?


"Why does increasing the load on the secondary coil circuit increase the current in the primary coil circuit"  This question is given as an exercise in my book. I can't figure out whether this is a poorly worded question or if I misunderstand. The answer I can come up with is that power is dissipated over the load so more power is needed to be supplied by the ac source. This seems too hand-wavy to me though, why would it not increase in the first place? How could it know that there is an increase in power needed if there was no change in current or magnetic flux from the secondary side to signify the change? Surely the component would just have a smaller potential drop?

I am happy to always not understand how does a transformer works ... One answer give me 10 questions ... (So I suggest you to not answer to this question, if you do not want to have more questions :D)  Here is the circuit :     So I put the "coupling" factor to 1, in order to have no leakage inductance and I set the value of the inductors very high in order to have a very low magnetizing current. So the primary current is approximately equal to the secondary current. My question is the following : How the primary current can reach an equilibrium to be equal to the secondary load current ? I will not accept answer which tells Pout is equal to ... So Pin is equal to Pout... There is something happenning into the transformer ...   Thank you very much and have a nice day !


I need a cross platform file system for an external hard drive that will be used on both Linux and MacOS. Will an ext4 file system work on MacOS right from the moment it is plugged in?

Since I have osxfuse installed it would be nice if I could use it. There are a  (heavily) outdated  here, saying that it is not . Is this still the case?


I am new to blender and using it for generating a dataset for another problem that I am working on. I use physics simulation to make objects fall. The problem I am facing is that the object.location value does not update after simulating. I can see that the objects did move in 3d view. Do I have to do something different to get the location in the last frame? (need python solution for this) I am using the following code for simulating  def simulate(start_frame=1, end_frame=200):    for i in range(start_frame, end_frame + 1):        bpy.context.scene.frame_set(i)        bpy.context.scene.update()

I'm trying to use blender to test the probabilities associated with different faces of non-cubic dice (some of you may even know why). I've already written a python script that randomly sets the objects position, rotation, initial linear velocity and initial angular velocity, then bakes the physics and jumps to a frame where the shape is likely in a settled position. The problem is that the rotation data at this frame seems to be the same as the frame right before the physics engine took over. It looks like the physics engine doesn't operate directly on object transformations. Is there a way to get this rotation information from python? Right now I can't even seem to find it in the UI.


I know we can have left and right cosets without having the group be normal, but can we mod out by a subgroup without it being normal and still get a group?  Thank you in advance!

Let $G \in \mathbf{Grp}$, $H \leq G$, $G/H := \lbrace gH: g \in G \rbrace$. We can then introduce group operation on $G/H$ as $(xH)*(yH) := (x*y)H$, so that $G/H$ becomes a quotient group when $H$ is a normal subgroup. But why do we only work with quotient groups by normal subgroups? If we introduce the notion of left quotient group in the above manner, how much good properties of a quotient group do we lose?


I want to build custom Ubuntu image(.iso) file with JRE and my application. I've already built my application on ubuntu. This ubuntu image i'm going to build should only run my application.I want a system, that is only capable to run my application. The application should start while the system is starting. Where should i look for resources to implement this?? Thank you.

I've been using Ubuntu for 2 years and now I want to make my own. I just decided to get the Ubuntu minimal iso for the core of my custom Distro ... but everything seems so confusing!!! could anyone give me some help about how to start and add some packages and X, a good documentation could help as well.


I cannot copy or create folders on an external drive. It says I'm not root. Please tell me which files do I have to post here, thanks a lot!

I had an old laptop. When it got complaint I removed its hard drive and started using it as external hard disk. It has an 80 GB of memory allocation for the windows C drive partition. But now i don't need that partition anymore. But the problem is I am not able to access that drive to paste files into it. How can I make read and write permission to this drive using terminal?


Take for example the set $X=\{a, b\}$. I don't see $\emptyset$ anywhere in $X$, so how can it be a subset?

Ever since day one of of my Mathematical Logic course, this fact has really bothered me. I cannot wrap my head around how an empty set is a subset of every possible set. Could someone kindly explain how this is true? Any help is appreciated!


I'm running geoserver-2.5.2. From an external server i would like to call it as a wfs source with ol3. For this I would like to allow this external server to access the data. It seams I need a header for cross-origin resource sharing (CORS). Like Zia has tried , the  wasn't helpful to me as well, as geoserver didn't work anymore after editing the web.xml file the way as described in the link.   I believe I do need the access for calling the wfs data.

I hope somebody has already figured this one out. I just installed Geoserver 2.9 on a vanilla Ubuntu 16.04 distro. The Geoserver 2.8 method of enabling CORS with the shanbe.hezoun class does no longer work with Jetty 9.2.13.  There are mentions that CORS support is already packaged with Jetty 9.2.13 in the jetty-servlets.jar.  The Jetty lib which is compiled with Geoserver contains a jetty-servlet-9.2.13.v20150730.jar in geoserver/lib but not jetty-servlets.9.2.13.v20150730.jar. Are these supposed to be the same jar with a different name?  It should be possible to enable CORS either in geoserver/etc/webdefault.xml or in geoserver/webapps/geoserver/WEB-INF/web.xml.  My understanding is that the webdefault.xml is applied first and the web.xml thereafter.  I have tried following filter in both xml. I haven't got as far as adding a filter mapping. Adding the filter alone will cause the Geoserver/Jetty service to not start proper.  <filter>     <filter-name>cross-origin</filter-name>     <filter-class>org.eclipse.jetty.servlets.CrossOriginFilter</filter-class> </filter>


What code does the following generate for me?   I Try this:  \begin{enumerate}[(a)] \item $5\in A$ \item $10\in A$ \item $3\in B$ \item $16\in B$ \item $9\in C$ \item $35\over 2\in C\cap D$ \item $35\in D$ \item $7\in (B\cap D)\cup A$ \end{enumerate} \end{multicols}   but this code generates

Code: \documentclass{article} \usepackage[a5paper]{geometry} \usepackage{multicol} \setlength{\parindent}{0cm} \begin{document} \begin{multicols}{2}   \begin{enumerate}   \item text 1   \item text 2   \item text 3   \item text 4   \item text 5   \end{enumerate} \end{multicols} \end{document}  Gives this:  How to move "text 5" upwards adjacent to "text 4"?


Suppose there are six distinct points in the plane. Let $m$ and $M$ be the minimum and maximum distances among the al possible distances between pairs of points. I have to show $M/m\ge\sqrt{3}$.  I have tried placing the points on the plane in an extremal fashion, but couldn't figure out how to derive such inequality.

Consider six distinct points in a plane. Let $m$ and $M$ denote respectively the minimum and the maximum distance between any pair of points.  Show that $M/m \geqslant \sqrt{3}$.


show sequence $a_n= \frac{1}{n+1}+\frac{1}{n+2}+...+\frac{1}{n+n}$ converges to log2  my attempt:   sequence $a_n$ is monotonic increasing 0<$a_n$<1/2   how to find limit?

What is the sum of the 'second half' of the harmonic series?  $$\lim_{k\to\infty}\sum\limits_{n=k+1}^{2k}{\frac{1}{n}} =~ ?$$  More precisely, what is the limit of the above sequence of partial sums?


When joining a list in python, join is a function of a str, so you would do >>>', '.join(['abc', '123', 'zyx']) 'abc, 123, zyx'  I feel like it would be more intuitive to have it as a property of a list (or any iterator really), >>>['abc', '123', 'zyx'].join(', ') 'abc, 123, zyx'  Why is this?

This has always confused me. It seems like this would be nicer:  my_list = ["Hello", "world"] print(my_list.join("-")) # Produce: "Hello-world"   Than this:  my_list = ["Hello", "world"] print("-".join(my_list)) # Produce: "Hello-world"   Is there a specific reason it is like this?


What's the best way to MySQL database that is only read-only, and will never have any modifications made to it.  1) I have increased my innodb_buffer_pool_size to 70% of available RAM  2) Increase query cache size to 40mb  Running against a load generator, after some time the database starts bottlenecking to only 1000 statements per second.  The configuration is 2-cores, 8GB ram 50GB SSD. The database contains a single InnoDB 13 GB table with the same exact query running on two indexed columns.  We are using a vertx server to hit the database. The symptom we see is that the web service performance degrades after 15-20 minutes of heavy load.  Where can the bottle neck be? What parameters should we optimize?

What's the best way to configure a MySQL database that is only read-only, and will never have any modifications made to it?  1) I have increased my innodb_buffer_pool_size to 70% of available RAM  2) Increase query cache size to 40mb  Running against a load generator, after some time the database starts bottlenecking to only 1000 statements per second.  The configuration is 2-cores, 8GB ram 50GB SSD. The database contains a single InnoDB 13 GB table with the same exact query running on two indexed columns.  We are using a vertx server to hit the database. The symptom we see is that the web service performance degrades after 15-20 minutes of heavy load.  Where can the bottleneck be? What parameters should we optimize?


Why is there constructor in abstract method when abstract method cant me instantiated?It is confusing me..  Code from tutorialspoint.com  public abstract class Employee  {    private String name;    private String address;    private int number;    public Employee(String name, String address, int number)     {       System.out.println("Constructing an Employee");       this.name = name;       this.address = address;       this.number = number;    }    public double computePay()    {      System.out.println("Inside Employee computePay");      return 0.0;    }    public void mailCheck()    {       System.out.println("Mailing a check to " + this.name        + " " + this.address);    }     public String toString()    {       return name + " " + address + " " + number;    }    public String getName()    {       return name;    }    public String getAddress()    {       return address;    }    public void setAddress(String newAddress)    {       address = newAddress;    }    public int getNumber()    {      return number;    } }   Now you can try to instantiate the Employee class as shown below:     * File name : AbstractDemo.java */ public class AbstractDemo     {        public static void main(String [] args)        {   /* Following is not allowed and would raise error */       Employee e = new Employee("George W.", "Houston, TX", 43);        System.out.println("\n Call mailCheck using Employee reference--");       e.mailCheck();     } }   When you compile the above class, it gives you the following error:     Employee.java:46: Employee is abstract; cannot be instantiated   Employee e = new Employee("George W.", "Houston, TX", 43);                ^ 1 error   What i m getting into trouble is if it has to show error why is their constructor in Abstract classes for what reason?

Can an abstract class have a constructor?  If so, how can it be used and for what purposes?


I am trying to create a model, but there is something that says there is "no such file or directory". What do I do?

I'm attempting to open a file on a Linux computer through file sharing. The file is stored on a Macbook Pro and both computers are running Blender 2.77. However, when I try to open the file on the Linux computer, I get an error of, "No Such File or Directory." I don't think this is a file permissions error as my permissions settings are set so that "Everyone" can read and write my file. What can I do to solve this?


I'm wondering why I a compile error in the following: #include <unordered_map>      template <typename T_Key, typename T_Value>     class Iterator     {public:         //std::unordered_map<T_Key, T_Value>::iterator iter;  // GIVES ERROR syntax error: identifier 'iterator'         std::unordered_map<int, int>::iterator iter; // WORKS              };

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


Newton introduced calculus, so I am wondering, did Einstein introduce anything important to mathematics?

Many great scientists have made important contributations to many related fields. Gauss, Euler and Newton each made many contributions to both math and physic.  One of the great scientists of last century is Albert Einstein and I wonder, did he make any contributations to math?


I have various tables in my document, and all of them have different widths. Is there a way I can evenly space out all of them, and have all widths equal to the width of the textblock (=pagewidth minus widths of margins)?  \documentclass[12pt]{article} \addtolength{\parskip}{\baselineskip} \usepackage[margin=1in,includefoot]{geometry} \usepackage[fleqn]{amsmath} \usepackage{mathtools} \usepackage{siunitx}  %Tables preamble \usepackage[none]{hyphenat} \usepackage{array} \usepackage[thinlines]{easytable} \usepackage{longtable} \usepackage{array, booktabs, makecell, multirow}   \renewcommand\theadfont{\bfseries\small} \newcommand\mceight[1]{\multicolumn{8}{l}{#1}} \newcommand\mctwelve[1]{\multicolumn{12}{c}{#1}}   \usepackage{arydshln} \setlength\dashlinedash{0.2pt} \setlength\dashlinegap{1.5pt} \setlength\arrayrulewidth{0.3pt} \usepackage{pdflscape} \usepackage{afterpage}  \widowpenalty500 \clubpenalty500 \exhyphenpenalty=50 %for line-breaking at an explicit hyphen \brokenpenalty=4991 \predisplaypenalty=10000 \postdisplaypenalty=1549 \displaywidowpenalty=1602 \floatingpenalty = 20000  % Header and footer \usepackage{fancyhdr} \pagestyle{fancy} \fancyhead{} \fancyfoot{} \fancyfoot[R]{ \thepage\ } \renewcommand{\headrulewidth}{0pt} \renewcommand{\footrulewidth}{1pt}  \usepackage{booktabs} \usepackage{dcolumn}    \begin{document}  \subsection{Appendix of Tables}  \newgeometry{margin=0.5in}   \begin{table*}[ht] \centering \fontsize{10}{12}\helvet \caption{Summary statistics 1} \begin{tabular}{l*{6}{S[table-format=2.2]}} \toprule & & & \multicolumn{3}{c}{Quantiles} \\ \cmidrule(lr){4-6} \textbf{Variable} & \textbf{Mean} & \textbf{Minimum} & \textbf{25th percentile} & \textbf{Median} & \textbf{75th percentile} & \textbf{Maximum} \\ \midrule \textbf{Panel A: Female labour force} \\ \midrule \textbf{2004-05} \\ \hdashline {Hourly wage}  & 17.17 & 0 & 3.75 & 5.48 & 12.5 & 250\ \\ \hdashline {Age (in years)}& 9.98 & 15 & 22 & 29 & 38 & 60\ \\ \hdashline {Years of experience} & 10.61 & 0 & 8 & 15 & 25 & 40\ \\ \hdashline {Years of education} & 7.13 & 0 & 0 & 8 & 12 & 16\ \\ \hdashline \\ \bottomrule \end{tabular} \end{table*}  \begin{longtable}{ l*{7}{S[table-format=2.2]} } \fontsize{10}{12}\helvet \caption{Summary statistics 2} \label{tab:...} \\ \toprule \multirow[b]{2}{*}{\thead{Dependent\\ Variables}}     &   \multicolumn{3}{c}{\thead[b]{Share(\%)}}         & \multicolumn{3}{c}{\thead[b]{Avg hourly wage}}             & {\multirow[b]{2}{*}{\thead{Avg\\ differential}}}              \\     \cmidrule(lr){2-4}\cmidrule(lr){5-7}     & \textbf{Men} & \textbf{Women} & \textbf{Pooled}     & \textbf{Men} & \textbf{Women} & \textbf{Pooled}                       \\    \hdashline                                                               \\ \endfirsthead %%%% \caption{Summary statistics 2 (cont.)} \\ \toprule                                     \multirow[b]{2}{*}{\thead{Dependent\\ Variables}}     &   \multicolumn{3}{c}{\thead[b]{Share(\%)}}         & \multicolumn{3}{c}{\thead[b]{Avg hourly wage}}             & {\multirow[b]{2}{*}{\thead{Avg\\ differential}}} \\   \cmidrule(lr){2-4} \cmidrule(lr){5-7}   & \textbf{Men} & \textbf{Women} & \textbf{Pooled} & \textbf{Men} &   \textbf{Women} & \textbf{Pooled} \\ \midrule \\ \endhead \midrule \multicolumn{8}{r}{\footnotesize\textit{Continue on the next page}} \endfoot\endlastfoot \mceight{\textbf{PANEL A: 2011-2012}} \\ \midrule \\ \mceight{\textbf{Panel A.1: Sector (Urban or Rural)}} \\ \midrule Rural  & 51.5 & 54 & 52 & 28.54 & 18.83 & 26.92 & 51.5 \\ \hdashline Urban  & 48.4 & 46 & 48 & 45.19 & 41.86 & 45    & 7.8 \\ \hdashline \bottomrule \end{longtable} \end{document}

I have the following table:  \begin{table}[htb] \begin{tikzpicture} \node (table) [inner sep=0pt] { \begin{tabular}{ l | l }   {\bf Symptom} & {\bf Metric} \\ \hline Class that has many accessor methods and accesses a lot of external data & ATFD is more than a few\\ Class that is large and complex & WMC is high\\ Class that has a lot of methods that only operate on a proper subset of the instance variable set & TCC is low\\ \end{tabular} }; \draw [rounded corners=.5em] (table.north west) rectangle (table.south east); \end{tikzpicture} \caption{God class symptoms} \label{tbl:god_class} \end{table}   Now I want to force the width of the table to be the same as the \textwidth, either by linewrapping of table text or by scaling. How can I achieve that?


I know he saves the hobbits from the barrow-wight and gives them weapons which affect the Nazgûl, Sauron's greatest servants. But I've always wondered why a high power, which Tom Bombadil obviously is, doesn't play a more significant part against Sauron. Gandalf says at the Council of Elrond that Tom wouldn't understand the struggle between Light and Darkness.    Asked if Bombadil might take the Ring for safekeeping, Gandalf replies:     "No," said Gandalf, "not willingly. He might do so if all the free folk of the world begged him, but he would not understand the need. And if he were given the Ring, he would soon forget it, or most likely throw it away. Such things have no hold on his mind. He would be a most unsafe guardian; and that alone is answer enough."          The Fellowship of the Ring, Book II, Chapter 2: "The Council of Elrond".    What confuses me is that if Sauron regains the One Ring, Tom will also fall like the rest of Middle-earth.  Is there any other info in the texts (aside from fact that Gandalf says that he basically doesn't care what happens) about why he didn't play a more prominent role?

There is evidence that Tom Bombadil is unaffected by the One Ring's power and he has magical ways about him that can't be explained.  It seems that Tom did not participate actively in the War of the Ring, even though he was clearly more powerful than others.  Is it possible that Tom Bombadil could have used his magic to defeat Sauron?


Title says it all, I'd like to know the advantages and disadvantages of both.

Google search brings up some articles on this topic, but they can be biased, so:  What are the advantages and disadvantages of buying physical gold vs. investing in a gold ETF like GLD, IAU, or SGOL?


I know I probably sound like a retard but I downloaded firefox earlier to replace netsurf because of stupid errors and I don't know how to open a browser that isn't netsurf. I have firefox-28.0.tar.bz2 downloaded and I need help to open it.

I have downloaded tar.gz files. But I don't know how to install it. How do I install this kind of file?


Create a filter, so that questions with a specific tag are not shown.   For example, in the sci-if group, I couldn’t care less about Harry Potter and it would be easier to browse if I could filter the many Harry Potter questions out.

I have set to ignore [php] tag and chose to hide questions in preferences:        But I still see questions tagged [php] in the iOS app.         Seems the app can't distinguish options for ignored tags.   App Version: 1.6.5.3 Device: iPad Air 2 (Wi-Fi) OS Version: Version 10.3.1 (Build 14E304)


I have a global variable $EMAIL. I want to loop through several files and for each that meets a criteria I will add it to $EMAIL for report generation.  The problem is when I redefine $EMAIL inside the loop it only changes $EMAIL at the scope of the loop iteration. The global version of $EMAIL remains empty.  This is a simplified version of my program:  #!/usr/bin/env bash  EMAIL="I echo without 'nope'" ls | while read line; do   if [ 73523 -lt 86400 ]   then     echo "Hasn't been backed up in over a day"     EMAIL="$EMAIL nope"   fi done  echo $EMAIL   How can I modify my script so that I can add to $EMAIL from inside the loop?    Edit/Update  I wanted to further simplify the example so I tried changing   ls | while read line; do   to:  for i in {1..2}; do   Strangely with this change nope is appended to $EMAIL, maybe I'm misunderstanding what is going wrong here?

With ksh I'm using read as a convenient way to separate values: $ echo 1 2 3 4 5 | read a b dump $ echo $b $a  2 1 $  But it fails in Bash: $ echo 1 2 3 4 5 | read a b dump $ echo $b $a     $  I didn't find a reason in the man page why it fails, any idea?


How many elements of  order $n$ does $S_7$ contain? Is there a general formula for to compute how many elements of order $k$ (for a given) in $S_n$?

I need to find how many elements of order $k$ are in $S_n$ (where $k \leq n$).   So if $k$ is prime, it's easy: $k$ can't be the $\mathrm{lcm}$ of any integers besides itself and one's (which we're omitting). So the length of the cycle then must be $k$, and the number of elements with $k$-length cycle representation in $S_n$ is given by $$\dbinom{n}{k}(k-1)!$$ But it gets really tricky when $k$ is not a prime number... I need to consider every set of integers that can divide $k$, and then, for every set, I need to find how many elements of that form are there... Or maybe I'm missing something here?  I need help figuring that out. thanks in advanced!


This question was presented as possibly off-topic and when I agreed I got the "You failed" message.  The question is about navigating a Haskell site and AFAICT has nothing to do with programming.  It's a "This site isn't behaving the way I expect, why is that?"  Please enlighten me.  How does this question fit into the SO guidelines?

Some people are complaining about the automatically generated audits. They are based on close reasons and apparently are a little controversial :-)          etc   I propose that for "good reviewers" (definition TBD) an extra UI component be added to let the reviewer suggest this as an audit item. Possibly:   Reject and add as audit button (Close and add as audit, etc) checkbox next to Reject, Close, etc checkbox on the Reject reason, Close reason etc dialog (could get messy, and some actions such as Reopen don't involve a subsequent dialog) dialog after rejecting, closing, Recommend Deletion, etc   Further, after passing or failing an audit, we could ask "good reviewers" "was this a good audit"? Bad audits, whether auto-generated or human suggested, could be removed from use if enough "good reviewers" identified them as such.  Now, what's a good reviewer? I don't want to judge only on behaviour in the review queue. I think flagging well is a good sign. So is editing - maybe an edit-related badge? And yes, some number of reviews would be good. Maybe some ratio of pass to fail on review audits. But not JUST what we do in the queues.  (I first suggested this in my answer to  but I'm bringing it up as a feature request of its own and to apply to all the queues.)


Lets assume there is a guy called Ben, he contacts some server for a ticket number and the server returns a random number to him. Ben then signs that number and sends it back to the server, which checks if its valid or not and accepts Ben's connection if it is. Assuming Ben then signs and sends emails on this server using his private key.  Pretend he uses the same private key to log in to a server and sign his emails. How could Ben's emails be forged. Assuming that the authentication mechanism signs the bare challenge without hashing, while for emails Ben signs the hash of the message body.  Only idea that come to mind at this point is it could be more or less an attack such as a Kerberos attack, where a malicious entity pretends to be the server and gives false positives to Ben. It could also be a chosen message attack or possibly having used the onetime of ElGamal signature again. What other things could it be and if one were to run into such a thing, what could be done to prevent it happening?

With regards to user authentication...   The server sends Alice a randomly chosen number. Alice signs the number and sends the signature back to the server. The server checks the signature using Alice's public key. If it's valid, the server accepts her connection request.   Suppose that Alice uses the same private key to log in to the server and sign her emails. The authentication mechanism signs the bare challenge without hashing, while Alice signs the hash of the email message.   Apparently, the server can forge emails from Alice under this scheme? If so, how could this be prevented?