I first tried to install the Wacom driver by following this:   When I ran ./configure, I saw this   checking for doxygen... no configure: WARNING: doxygen not found - documentation targets will be skipped   I wasn't sure if that was a problem or not. I decided to follow this:   so I typed   sudo apt-get install xutils-dev libtool xserver-xorg-dev libx11-dev libxi-dev libxrandr-dev libxinerama-dev libudev-dev   I then ran make and got  make[1]: Entering directory '/home/Downloads/xf86-input-wacom-0.33.0' Making all in conf make[2]: Entering directory '/home/Downloads/xf86-input-wacom-0.33.0/conf' make[2]: Nothing to be done for 'all'. make[2]: Leaving directory '/home/Downloads/xf86-input-wacom-0.33.0/conf' ... Making all in tools make[2]: Entering directory '/home/Downloads/xf86-input-wacom-0.33.0/tools' make[2]: Nothing to be done for 'all'. make[2]: Leaving directory '/home/Downloads/xf86-input-wacom-0.33.0/tools' Making all in test make[2]: Entering directory '/home/Downloads/xf86-input-wacom-0.33.0/test' make[2]: Nothing to be done for 'all'. make[2]: Leaving directory '/home/Downloads/xf86-input-wacom-0.33.0/test' make[2]: Entering directory '/home/Downloads/xf86-input-wacom-0.33.0' make[2]: Leaving directory '/home/Downloads/xf86-input-wacom-0.33.0' make[1]: Leaving directory '/home/Downloads/xf86-input-wacom-0.33.0'   This seemed ok, so I then tried sudo make install  ...  /bin/mkdir -p '/usr/bin' /bin/bash ../libtool   --mode=install /usr/bin/install -c xsetwacom isdv4-serial-debugger isdv4-serial-inputattach '/usr/bin' libtool: install: /usr/bin/install -c xsetwacom /usr/bin/xsetwacom libtool: install: /usr/bin/install -c isdv4-serial-debugger /usr/bin/isdv4-serial-debugger libtool: install: /usr/bin/install -c isdv4-serial-inputattach /usr/bin/isdv4-serial-inputattach make[2]: Nothing to be done for 'install-data-am'. make[2]: Leaving directory '/home/Downloads/xf86-input-wacom-0.33.0/tools' make[1]: Leaving directory '/home/Downloads/xf86-input-wacom-0.33.0/tools' Making install in test make[1]: Entering directory '/home/Downloads/xf86-input-wacom-0.33.0/test' make[2]: Entering directory '/home/Downloads/xf86-input-wacom-0.33.0/test' make[2]: Nothing to be done for 'install-exec-am'. make[2]: Nothing to be done for 'install-data-am'. make[2]: Leaving directory '/home/Downloads/xf86-input-wacom-0.33.0/test' make[1]: Leaving directory '/home/Downloads/xf86-input-wacom-0.33.0/test' make[1]: Entering directory '/home/Downloads/xf86-input-wacom-0.33.0' ... make[1]: Leaving directory '/home/Downloads/xf86-input-wacom-0.33.0'   I assumed this meant there were no errors. However, I don't see Wacom anywhere. I even typed   xsetwacom --list devices sudo find . -name wacom\* | grep modules   but there was no output for either of those commands.   lsmod | grep wacom just gave  wacom                  81920  0 hid                   118784  3 wacom,hid_generic,usbhid   I then followed this:   However, after sudo apt-get install wacom-dkms  I got   Error! Bad return status for module build on kernel: 4.2.0-36-generic (x86_64) Consult /var/lib/dkms/wacom/0.30.0/build/make.log for more information.   I then checked /var/lib/dkms/wacom/0.30.0/build/make.log and its contents are  DKMS make.log for wacom-0.30.0 for kernel 4.2.0-36-generic (x86_64) Building input-wacom drivers for 2.6 kernel. make -C /lib/modules/3.13.0-68-generic/build M=/var/lib/dkms/wacom/0.30.0/build/3.7 make[1]: *** /lib/modules/3.13.0-68-generic/build: No such file or     directory.  Stop. Makefile:24: recipe for target 'all' failed make: *** [all] Error 2   Can anyone help?


Subadditive sequences and the limit $\sup_{n\to\infty} a_n / n$

Let $\{ a_n, n\geq 1\}$ be a sub-additive sequence, i.e. for any $m,p\geq 1$ $$ a_{m+p} \leq a_m + a_p. $$ .Prove that $$\lim_{n\to\infty} \frac{a_n}{n} = \inf_n \frac{a_n}{n}.$$ I guess the first step is to state $$a_{n} = a_{mp+q} \leq a_{mp} + a_q$$ but I'm not sure where to go from here....


Using jQuery with apex:tabPanel in visualforce

I am using jQuery library in my visual force page, but I've faced a major problem when I tried to use tabs "apex:tabPanel".  <script src="{!$Resource.jQuery}"></script> <!-- If I delete this script the tabs work !! -->  <apex:tabPanel tabClass="activeTab" inactiveTabClass="inactiveTab">   <apex:tab label="Tab#1" id="tab1"></apex:tab>   <apex:tab label="Tab#2" id="tab2"></apex:tab> </apex:tabPanel>   I get a "JS" errors in the console when I try to click on any tab, but if I delete jQuery library it works. So I guess there is a conflict between jQuery and apex:tabPanel functionality.    Here's what I got in the console   Uncaught ReferenceError: initViewstateTab is not defined  Uncaught TypeError: Object [object Object] has no method 'dispatchEvent'  Uncaught ReferenceError: initViewstateTab is not defined  event.returnValue is deprecated. Please use the standard event.preventDefault() instead. Uncaught TypeError: Object [object Object] has no method 'hasClassName'  Uncaught TypeError: Cannot call method 'replace' of undefined


How can I change the field names (not the alias) in ArcGIS 10.2? I already found this page on ArcGIS support: "" but there is is not "Defense Mapping" on Customized Mode Categories In my ArcCatalog! Without access to Defense Mapping, how can I change the field names?


can you please tell me if my proof is right or if I'm taking some steps for granted? Thanks  $$\forall a, b\in \Bbb R \Rightarrow (-a)b=-ab$$  $$(-a)b\cdot (-a)^{-1} = -ab\cdot (-a)^{-1} \\ 1\cdot b = \frac{-ab}{-a} \\ b=b $$


What is the benefit of interfaces when you still need to define each method body separately in each class that implements it?

I'm trying to wrap my head around interfaces and I've been reading a lot of similar questions/answers on the topic, but it's still not clicking with me. I understand what an interface literally is, but I don't get why you would ever use it. So an interface contains a bunch of empty functions, and you then implement that interface in a class. But what I don't get is, you still have to write a full function declaration for any function you take from the interface. So say you have a function 'void printHello()' in your interface, and you implement that interface in a class. You still have to write: public void printHello() {      System.out.println("Hello!"); }  which is a complete function declaration. You could delete the 'implements interface' command and literally nothing would change, you would still have a working function 'printHello()'. So functionally speaking, isn't the interface basically doing nothing? To go further, you could have another class that also implements the same interface, but you could make the same function do something completely different: public void printHello() {      System.out.println("Bababooey!"); }  So it's not like it's pre-defining functions so you can call them anywhere like a class/object would do. If this is the case what is the interface really providing?


What are good examples to demonstrate Einstein's mass-energy relation

According to Einstein's  mass and energy are interchangeable. Can you provide some examples where:   Mass gets converted into energy. Energy gets converted into mass.


How to find out why Eclipse is freezing?

Every time i run any junit or any job [ spring-batch ] from eclipse. It hangs for around 10-15 mins. After that everything goes fine. Now, i would like to know in such cases what are the steps you take or what are the tools you use to rectify the problem.  Till now i am unable to resolve the problem. Please help. Should i post the Thread dump here?


Why my render doesnt reflect the color and properties of my shaders applied to the object?

The bronze effect is with the help of quixel textures and there is an HDR image in the background. How do I preserve those effects and bronze texture in a render animation or image?  I'm using the shader mode and I have checked the transparency also, in the film section of the render properties. For the Render, I´m using Cycles with CPU toggled on.


Old English sounds and Germanic languages

What languages still use the 'ge' prefix that was part of the Old English grammatical structure?  I've searched and found German, but am not sure that is the only one which still does.  I'm interested, because I am involved in a conversation regarding how we know what Old English sounded like. (I've seen this question:  but it didn't seem to provide the answer I'm seeking.)


Is there a way to always force the tab bar to show?  I go to Settings → Preferences → General → Tab Bar and uncheck hide, but the next time I open Notepad++, the tab bar is gone, even if I drag multiple files into the window.


Simple question (I seem have asked a few like this...)  What is $\mbox{Hom}(\mathbb{Z}/2,\mathbb{Z}/n)$? (for $n \ne 2$)


Down-voting questions that belong elsewhere. Do or don't?

I frequently see questions on Stackoverflow.com that belong on Superuser or here on Meta. Prior to being moved or migrated, they are frequently down-voted.   Should they be down-voted for such a condition? What if the question is legitimate and well-worded, just posted on the wrong site to begin with? And finally, are the votes for the question reset to 0 when it is migrated?


What's wrong with keeping frozen vegetables in refrigerator?

The bags of frozen mushrooms and okra that I just bought got mistakenly put into the refrigerator for a few days instead of frozen. I want to eat them now.  What's the problem with letting bagged veggies thaw and then eating them? Is there a danger of food poisoning?


I have a laptop which is running Ubuntu which I want to uninstall so I can install Windows instead

I have just acquired a laptop which is running Ubuntu. I have no experience with Ubuntu so I want to uninstall it and install Windows instead. I have no idea how to do this so if anyone can help, I would appreciate it.


Rasterize (R package raster) fails to rasterize island polygons?

I am having problem in rasterizing a polygon shapefile: "island" polygons (I mean polygons which are totally included into a larger one) are ignored and do not appear in the raster. My code is:  seg <- readOGR(dsn="my path", layer="seg_10_9_5s")  map <- raster(map2007.tif) # import of raster of same extension than shape # the shape has only a field with a unique id for each polygon length(unique(seg@data$id))  # give me the right number of polygons (1568) print(seg@data)  # everything seem OK nrow(seg@data)   # 1568 idpol <- unique(seg@data$id)  # give me a vector of 1568 id values  # rasterize the polygons segr <- rasterize(seg,map,"id") writeRaster(segr, filename="seg.tif", mat="GTiff", overwrite=TRUE,datatype='INT2S')  # I  look for the values of grid cells freq <- freq(segr)  # freq has only 1492 rows! f <- freq[,1] f # I compare the list of value in vector and raster setdiff(idpol,f)  # id of polygons which are absent from the raster   In QGIS I display the shape and seg.tif, the polygons identified as lacking in raster were not rasterized, the cells get the value of the surrounding polygon.  Maybe the problem is with the original shapefile? but it seems OK.  I put the shape and the map in    Can anyone see what I'm missing here?


I am trying to get the rightmost header to be centered with the numbers in its column.  From the MWE below, my table compiles with the rightmost header skewed to the right.  Can you help me center align the rightmost header to the numbers in its column so that it will be consistent with the other three entries of the table?   Here is the code:  \documentclass{book} \usepackage[top=3cm,bottom=3cm,left=3.2cm,right=3.2cm,headsep=10pt,a4paper]{geometry} \usepackage{pgfplotstable, booktabs} \pgfplotsset{compat=newest} \usepackage{longtable} \usepackage{amsmath} \usepackage{array} \usepackage{fancyhdr} \pagestyle{fancy} \fancyhf{}  \usepackage{filecontents} \begin{filecontents}{TABDAT1.txt} c   G(c)GTOT    GhatGTOT    MODELPERFORM 0.994680851 0.067915691 0.067915691 1 0.989361702 0.135831382 0.114754098 0.844827586 0.984042553 0.18735363  0.182669789 0.975 0.978723404 0.234192037 0.201405152 0.86 0.973404255 0.271662763 0.227166276 0.836206897 0.968085106 0.306791569 0.255269321 0.832061069 0.962765957 0.339578454 0.306791569 0.903448276 \end{filecontents}  \begin{document}   %%% Code from Dr. Christian ------ for not using headers.---------------------- \pgfkeysifdefined{/pgfplots/table/output empty row/.@cmd}{     % upcoming releases offer this more convenient option:     \pgfplotstableset{         empty header/.style={           every head row/.style={output empty row},           outfile=pgfplotstable.example1.out.tex,         }     } }{     % versions up to and including 1.5.1 need this:     \pgfplotstableset{         empty header/.style={             typeset cell/.append code={%                 \ifnum\pgfplotstablerow=-1 %                     \pgfkeyssetvalue{/pgfplots/table/@cell content}{}%                 \fi             }         }     } }  \noindent {\scriptsize \pgfplotstabletypeset[col sep=space,empty header, columns={c,G(c)GTOT,GhatGTOT,MODELPERFORM},      % display specified columns begin table=\begin{longtable}, end table=\end{longtable}, columns/c/.style={column type={c},dec sep align,precision=4,fixed,fixed zerofill}, columns/G(c)GTOT/.style={column type={c},dec sep align,precision=4,fixed,fixed zerofill}, columns/GhatGTOT/.style={column type={c},dec sep align,precision=4,fixed,fixed zerofill}, columns/MODELPERFORM/.style={column type={c},dec sep align,precision=4,fixed,fixed zerofill}, every head row/.append style={before row={%     \caption{This is a Table with Data}%     \label{tab:DataTable}\\\toprule     \multicolumn{2}{c}{\emph{c}} & \multicolumn{2}{c}{$\dfrac{G(c)}{G_{TOT}}$} & \multicolumn{2}{c}{$\dfrac{\hat{G}(c)}{G_{TOT}}$} & \multicolumn{2}{c}{$\phi(c)$} \\[7pt] \toprule     \endfirsthead     %     \multicolumn{8}{c}%     {{\bfseries Table \thetable\ Continued from previous page}} \\     \toprule     %     \multicolumn{2}{c}{\emph{c}} & \multicolumn{2}{c}{$\dfrac{G(c)}{G_{TOT}}$} & \multicolumn{2}{c}{$\dfrac{\hat{G}(c)}{G_{TOT}}$} & \multicolumn{2}{c}{$\phi(c)$} \\[7pt] \toprule     \endhead     %     \midrule \multicolumn{8}{r}{{Continued on next page}} \\ \bottomrule     \endfoot     %     \midrule     \multicolumn{8}{r}{{End of Table}} \\ \bottomrule     \endlastfoot     }}, ]{TABDAT1.txt}  \end{document}


Is there any way to verify a Ubuntu iso or hashsum via HTTPS?

Neither the ISO nor the hashsum is available via HTTPS. Is there any way to verify you're not getting man-in-the-middled?


I am active on Stack Overflow. I saw that one of my question has more than 10,000 views but the  badge wasn't awarded to me.  Why not?


Is it possible to continuously add in a loop?

I'm using a node module to create http proxy servers (node-socks)like this: const { http } = require('@sansamour/node-socks')     http.createServer({     authorization: function(u,p){         return u == 'KeemROH' && p == 'Test'     },     port: 5000 });  http.createServer({     authorization: function(u,p){         return u == 'KeemROH' && p == 'Test'     },     port: 5001 });  http.createServer({     authorization: function(u,p){         return u == 'KeemROH' && p == 'Test'     },     port: 5002 });  http.createServer({     authorization: function(u,p){         return u == 'KeemROH' && p == 'Test'     },     port: 5003 });  http.createServer({     authorization: function(u,p){         return u == 'KeemROH' && p == 'Test'     },     port: 5004 });  Would it maybe be possible to make a loop that would maybe run: http.createServer({     authorization: function(u,p){         return u == 'KeemROH' && p == 'Test'     },     port: 5000 // add +1 each loop so 5000, 5001, 5002, 5003, 5004 ect. });  And have it loop a set number of times? So instead of rewriting it a number of times this can be the solution


We have a successful SDK for which we would like to create a Q&A forum, and naturally we love SO. Is there a way to create a stackoverflow-like website for my own SDK purposes for Q&A?  I see there are 105 stack-exchange websites, but I guess they're all owned and managed by stack-exchange... Is there a way to create another one for my company's purposes?


Less voltage more amp? switch characteristis

I have a question regarding switches, relays etc  Ex, if I have a switch rated for 24v 0.5a, can the contacts then safely handle 12v up to 1a? Because the power passing the switch is the same? Or should I anyway use a 12v 1a switch?


What is the difference between "into" and "onto"?

I see both used, at times, almost interchangeably. What are the general guidelines?


How to get Latex/overleaf to cite in the right order using two column and bibtex?

\documentclass{article} \usepackage[utf8]{inputenc} \usepackage[english]{babel} \usepackage[T1]{fontenc} \usepackage{physics} \usepackage{lmodern} \usepackage{amsmath} \usepackage{amssymb} \usepackage[version=3]{mhchem} \usepackage{subcaption} \usepackage{float} \usepackage{xcolor} \usepackage[section]{placeins} \usepackage[normalem]{ulem} \usepackage{gensymb} \usepackage{mathrsfs} \usepackage[tmargin=20mm, bmargin=20mm]{geometry} \usepackage{lipsum} \newcommand{\vect}[1]{\boldsymbol{1}} \usepackage{parskip} \usepackage{graphicx} \usepackage[font={small, it}]{caption} \usepackage{siunitx} \usepackage{float} \usepackage{babel} \usepackage{mhchem} \usepackage{dblfloatfix} \usepackage{multicol} \floatstyle{plaintop} \restylefloat{table}   \title{Semester assignment 241} \author{Some guy} \date{April 2019}   \begin{document}  \maketitle \vspace{2em} \begin{multicols}{2} \raggedright   \section*{Introduction} As the world's demand for power increases, so does the need for lower carbon emissions. The way the world is going today, it does not seem like humanity will be able to keep their ''two degree'' goal. By using renewable energy, one can both lower emissions and increase power generation. But some issues renewable energy face are that they often take up a large area, and that they can be inconsistent. The sun isn't always shining, the wind isn't always blowing and the dams are reliant on regular precipitation.   Then there are nuclear power plants, which produce large amounts of power with no release of CO$_2$. Fission reactors produce about 11\% of the worlds power \cite{worldnuclear}. Relative to carbon emissions, they are good for the environment, but they have one major drawback, which is the nuclear waste left behind. The nuclear waste can stay radioactive for hundreds of years, and needs the be treated and stored in a special way.  But in the last 10 years, a new kind of nuclear reactor has been looking more promising, and that is the fusion reactor. They have the possibility of producing even more energy, but without any nuclear waste or carbon emissions. The main difference between fission and fusion is that fission is about splitting atoms into lighter ones, while fusion is about fusing atoms into heavier ones.  On the basis of this, one can raise the question: Can fusion power plants replace fission power plants if nuclear fusion becomes feasible?  \section*{Theory}  One of the most interesting aspects of fusion reactors, is the potential amount of fuel available, and the theoretical amount of power it can produce. If you look at the amount of energy produced by fission of \ce{^{235}_{92}U}, its about 200 MeV, which is 0.85 MeV/u \cite{lecture}. Fusion on the other hand, produces a lot more energy. \begin{equation}     \ce{^{2}_{1}H} + \ce{^{3}_{1}H} \xrightarrow{} \ce{^{4}_{2}He} + \ce{^{1}_{0}n}  \; \; \; \; \; \; \; \; Q = 17.59\;MeV \end{equation} From equation (1), one can see that the amount of energy released is lower, but if you compare the mass involved, its $\frac{17.59}{5} = 3.5\;MeV/u$ which is more than 3.5 times more than that of fission \cite{lilley2013nuclear}.   Compared to mining Uranium, it is a lot easier to acquire deuterium, as it makes 0.03\% of all the water in the ocean \cite{serway2004physics}.   \bibliographystyle{plain} \bibliography{References.bib} \end{multicols} \end{document}   I have the problem that I'm using two columns, and cite something at the middle of the page on the left side, then on the top of the right side. The citations on top right gets numbered [1] and [2], and the first citation on the left side gets numbered [3]. This is probably because the citation order is decided by which citation is the top-most one, not necessary the first one you'd read. Its annoying because the first citation you read is then marked as [3].  I'm using Overleaf and BibTeX  Any way to fix this easily?  Sorry for the amount of code  .


I wish to drive a MOSFET using a 555. I dont have a driver handy, will it be fine to use a transistor instead? So the output of a 555, could activate a transistor(as swtich), which allows a source to drive the FET?


Downgrade PHP Version from 5.5 to 5.4 on Ubuntu 14.04

First time I've ever needed to ask a question here that I don't think has already been answered.  I've recently been working on transferring over a vBulletin site I run to a new server. Thinking that I was being all ahead of the curve, when I went to install Ubuntu on it recently and saw 14.04 was available, I went for it.  As I should have expected, it's a nightmare. Turns out that vBulletin JUST added support for PHP 5.4 with their last release on the version I run. I honestly don't expect them to ever get it up to PHP 5.5 (what 14.04 installs by default).  Save from going back to 12.04 LTS and starting completely over, is there a way I can downgrade the PHP version installed to 5.4? I saw some threads talking about this for going from 5.4 to 5.3, so I'm hoping its doable.  The simpler you can help me to do this, if possible, the better. I know my way around, but by no means consider myself an expert. Thanks!  EDIT: For clarity. Need to downgrade PHP from 5.5 to 5.4 on 14.04 (Trusty Tahr).


How to report Mod if a user is using more than one account to upvote his/her own questions/answers?

Is there any place where we could report this so that the moderator takes appropriate action against the user who is using multiple accounts to upvote his/her own answers?


60's short story where siblings find in mechanical toy that emits light

I am trying to find a short story I read as a kid in the 60's. It is about a little boy and his younger sister who find this mechanical toy dropped by aliens into their backyard. The box emits patterns of light. The little boy can figure out the patterns for awhile, but then realizes his younger sister has a much greater understanding of the box. The aliens come for her in the end.   Does anyone know this story?


How to solve $x^TAy = d$, where $A$ and $d$ are known, x and y remain unknown.

How to solve $x^TAy = d$, where $A$ and $d$ are known, $x$ and $y$ remain unknown. $x$ and $y$ are vectors; $A$ is a matrix; $d$ is a scalar. There are constraints for $x$ and $y$, requiring $x$ and $y$ sums up to 1, and all elements greater equal than zero, i.e., $x^T \mathbf{1} = 1, x \geq \mathbf{0}$ and $y^T \mathbf{1} = 1, y \geq \mathbf{0}$ There may be infinite solutions, but I just need one.


Is there a Map implementation in Java that will use case-insensitive String matching for the key, but also supports the null key? I know that  new TreeMap<String, String>(String.CASE_INSENSITIVE_ORDER)   supports case-insensitive matching of String keys, but it doesn't support the null key.


Few times I have decided to change my vote. The problem is that when originally answer is 0 and I vote up and after some though I want to reverse my vote, it goes to -1 vote.   Why not 0?  I don't want to vote for negative, just reverse my vote...


Save a value of variable in a standalone application

I have a simple string variable and I want to save the value when starting application, the application is a standalone and I don't want to use registery. I tried to put the string as settings but it saved in a app.config file.  can I save a variable in the self application?


Does Private Sanctum prevent Rope Trick from being cast?

Private Sanctum states:  • Planar Travel is blocked within the warded area.  Rope Trick states:  ... an Invisible entrance opens to an extradimensional space that lasts until the spell ends. The extradimensional space can be reached by climbing to the top of the rope.  Would Private Sanctum prevent Rope Trick from being used? RAW it does not seem like it.


I used NetBeans for Java development on Windows and remember finding it in the Ubuntu Software Center on Natty, but now it's gone. Is there a PPA I can use or will it be re-added to the official repos?


Forcing a vote on the question before an answer can be submitted

I notice that there are quite some questions that get no up/down vote, but do have some answers. This surprises me, as I would assume that someone who takes the time to answer a question has an opinion on that question. He either thinks it's good (up vote) or bad (down vote, edit, flag, close). In the latter case he should not take the time to answer the question, but instead devote that time to improve it, or ask for clarification. Here's an example of such a question on  and .  Do you think it is a good idea to force a vote before one can answer the question? Why (not)?  Update: Meta and community wiki's should be excluded from the force-vote system as with meta voting servers a different purpose and community wiki's might have more answers from one person (which would create a need for multiple votes).  Update 2: I see that a relevant question is asked . The different answers include  and . The highest rated answer reflects the idea presented in  to my question, but from a slightly different perspective. It just states that the main goal of the site is to write/rank answers. A suggestion is made to make the question vote buttons visually more outstanding to  motivate people to vote on the question.


What is Big O Notation's length measured in?

I am using quicksort, which is NLog(N), and have 20 items to sort.   Worst case is there for 26.02.... seconds? Really, seconds? I find that hard to believe, so what is the length measured in?


Why i have a NullPointerException when i set Calendar.getInstance() in a attribute of model?

In my model i have this:  @Entity public class Plan {   ...   @Temporal(TemporalType.TIMESTAMP)   @Column(nullable = false)   @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")   private Calendar creationDate;   ...   In eclipse debugger, i have a NullPointerException in this line:  plan.setCreationDate(instance);


I am using the function below to match URLs inside a given text and replace them for HTML links. The regular expression is working great, but currently I am only replacing the first match.  How I can replace all the URL? I guess I should be using the exec command, but I did not really figure how to do it.  function replaceURLWithHTMLLinks(text) {     var exp = /(\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/i;     return text.replace(exp,"$1");  }


Install all packages containing a certain prefix (in Ubuntu 20.04)

In Ubuntu 18.04 if I wanted install all packages with the prefix postgresql, I use the command sudo apt install postgresql* but in Ubuntu 20.04 it seems there are some packages which contain * so this command doesn't work like I wanted. Is there any solution to install packages which contain a certain prefix in Ubuntu 20.4?


Singular or plural verb after a series connected by "or"

The following sentence refers to an apocalyptic story where money no longer has any value:     A can of sardines, radio batteries, or a bicycle is/are more precious than money.   Should I use is or are after the series?


Difference between deploy methods : ChangeSets vs migrationTool?

I am new to salesforce and just discovered that there are two options to deploy metadata to production:   using ChangeSets  using Force.com Migration tool   Could somebody please clarify me on which one to use under what conditions?


I have downloaded the ACM tex package from its . When I want to build a sample tex file in this folder, it complains that the acmart.cls file is not present. When I wan to run make command (think that the class file is going to be built), I get a make error which says LaTeX Error: Fileenviron.sty' not found`.   How can I use that package?


I have gone to an electronics store and have tried on Bose and Beats headphones, both of them have a pretty annoying sound delay which is insanely apparent and anyone who says it’s imperceptible must be deaf.   While listening to music it doesn’t matter and for videos it wouldn’t be that bad, for phone calls especially slower or international VOIP which already have the delay, it is absolutely horrible.   I noticed that the more expensive the receiver - the lesser is the sound delay, I also noticed that it is some sort of low power garbage which causes that delay to happen.   Example: streaming Bluetooth music to my PC one time is super snappy almost perfectly in sync without any perceived delay, some other time there’s like a half a second delay (distance would be irrelevant) although I am tempted to try to force high power by moving too far from the receiver, and then seeing if that has forced high power low latency  Example 2: I have these cheap $25 bluetooth earphones for running, they have a really bad half a second delay.  Considering radio waves travel with the speed of light, I am very tempted to deposit a log of blame on the “low power” protocols and inability to force high power low latency protocols for this issue.   Low power protocol is fine for synchronizing irrelevant garbage to/from your watch, music, file transfers, I strongly disagree how it is being used for media and calls.  That said, I wonder how is the delay on AirPods in comparison to latest (2k17/18) Bose. Bose delay isn’t that bad, but still would add an annoying delay for phone calls.


Word for the act one does with one's hand when shooing someone/something

Often, when someone yells "shoo", or "get out of here", it is often accompanied by a hand gesture. It looks kind of like a brush through the air, only more aggressive, and sometimes it kind of looks like they're pointing them away.


In the category $\mathbf{Set}$ is "the product of an empty set of sets a one-element set"?

I was reading  on Category Theory and it said (paraphrased to add context):     Exercise 4: Explain why in $\textbf{Set}$ (the Category of Sets), the product of an empty set of sets is a one-element set.   which I think is incorrect. The product of two empty sets (or any number) is empty because we are considering:  $$ \emptyset \times \emptyset = \{ (a,b) : a \in \emptyset, b \in \emptyset \} = \emptyset$$  where $a \in \emptyset , b \in \emptyset$ are false, so the above is the $\emptyset$ which is NOT a one element set (its a zero element set).   This should be trivial so I am assuming I am somewhere mis reading the natural language of the exercise. Someone help me catch where is it and what the answer should be? i.e. whats being asked and the answer?


How is electro-magnetic wave formed without medium?

There are particles in a medium. When these particles oscillate with SHM motion, a flow is formed. That is called a wave.  But when there is no medium, there is no oscillation. That means no flow. Eventually no wave!   But electro magnetic wave is formed without any medium. How is it possible?  Again so many said,"EM waves are the oscillation of EM field. " Oscillation of particles mean "particles are getting down and up continuously". Then what does "oscillation of EM field " mean?


I have table in database which stores few queries, Using sqlcmd I am trying to retrieve the queries. While doing so, the select * from abc is getting replaced with 'select  from abc'  How to overcome this issue?  Edit:  Max_Values=5 n=1 while [ $n -le $Max_Values ] do Sql_Qry="set nocount on;Select Query from dbo.abc With(nolock) Where RowID=$n"    Query=`/opt/mssql-tools/bin/sqlcmd -S Server_name -U UserID -P Password -d database -Q "$Sql_Qry" -h -1` echo $Query n=$(( n+1 )) done   Expected Output:   Select * from Int.Table1   Actual Output:   Select Script1.txt script2.sh script3.sh from Int.Table1   The script1, script2 and script3 are files within the current directory


GitHub-like punchcard with the help of pgfplots

Is it possible to create a punchcard so it will look like the same on  with the help of pgfplots?  The data stored in punchcard.dat:  0 Monday 18 1 Monday 67 2 Monday 62 <hour> <day> <commits>


Which livestock is the most efficient food source?

Given chickens, sheep, and cattle, which livestock provides the most efficient (i.e. highest yield) source of food given a 20x20 field.   Does the answer change given different sized field?   Is one livestock type more efficient for any period of time (i.e. Chickens are more efficient for the first 5 years, after that cattle).


jQuery if input value matches character in div

Here is my html   <input type="text" />

Apple

Peach

Bannana

Tomato

   And my jQuery code yet  var items = $("div").find("p").text();  console.log(items);   How can I highlight each character inside div p that matches value in input? Let's say that users write down in input character "a". Page should look like this, even A character in apple should be bold.   Apple  Peach  Bannana  Tomato  here is  as well


How can we prove it? ${a}{b}≤\frac{a^p}{p}+\frac{b^q}{q}$


Why does Maeve do this in the last episode of Westworld?

In the last episode of Westworld,       Maeve goes into a train which is going to leave the complex. She had a hard time going there, but on the last minute, she changes her mind and leaves the train to reenter the park and take part in the revolution.   So..      Why does she leave the train ? Was it a "robotic command" send to all robots, and thus, she could not resist ? Or was is her free-mind ? The memory (false) of her daughter ? Something else ?


Question about Casella and Berger's proof of MLE invariance

In Casella and Berger, p. 320, they have a proof of the invariance of the MLE. Let $g: \theta \mapsto \eta$ be a function. They define the induced likelihood as  $$ L^*(\eta \mid X) = \sup_{\{\theta: g(\theta) = \eta\}} L(\theta \mid X). $$  This ensures that $g$ is one-to-one with respect to the likelihood functions because if $g$ is not one-to-one, there may be multiple values of $\theta$ that map to a given $g(\theta) = \eta$.  Then they note  $$ \sup_{\eta} L^*(\eta \mid X) = \sup_{\eta} \sup_{\{\theta: g(\theta) = \eta\}} L(\theta \mid X) = \sup_{\theta} L(\theta \mid X). $$  The first equality just applies the definition of the MLE of $\eta$. However, the next inequality confuses me. They write,     The second inequality follows because the iterated maximization is equal to the unconditional maximization over $\theta$...   Can someone justify this claim or provide some intuition if the claim is supposed to obviously follow from definitions?


Prove that $a^2 + b^2 \geq 8$ if $ x^4 + ax^3 + 2x^2 + bx + 1 = 0 $ has at least one real root.

If it is known that the equation $$ x^4 + ax^3 + 2x^2 + bx + 1 = 0 $$ has a (real) root, prove the inequality $$ a^2 + b^2 \geq 8. $$  I am stuck on this problem, though, it is a very easy problem for my math teacher. Anyway, I can't figure out.


If a number N is given to us. Is there any way to find all the combinations of numbers whose LCM is N?


Taking Roissy Bus from Place Charles de Gaulle Etoile to CDG Terminal 2

I am confused because on they Way to Paris from CDG I took Roissy Bus to Opera. It did not stop at CdG Etoile. Today I am very busy going to CDG airport. Is there a stop at etoile? The web page is not clear about this.


Is it correct to use "all this" instead of "all of this"?

I frequently see people write "all this", instead of "all of this". Is this a grammatically correct phrase? My intuition tells me that it's wrong (the spoken phrase "all this" is really a contraction of "all of this"); but I'm having a hard time finding any evidence to support the claim.


Excel Changes Dates into Numbers Automatically

Everytime I enter a date into a cell (e.g. 11/6/1989), Excel keeps changing it into a five or six digit number.  How can I get it to stop doing this?


problem on extremum values of multi-variable function

I have tried using the formula rt- s^2 but its value is 0 . now how do I search for the points at itsmaximum and minimum.


I am writing a paper with ieeeconf style. Now I added an lstlisting but the numbering is slighty off the normal text-region. You can see it here:    Can someone help me to fix this?  Code:


Difficulties installing zoom_amd64.deb on a Dell XPS 9750 with Ubuntu 20.04 LTS

I've updated my Dell XPS 9750 with a fresh install of Ubunty 20.04 LTS (I had to resize the partitions as the Windows 10 partition needed more disc space).  Upon finishing the installation and updating of Ubuntu, I tried installing zoom_amd64.deb.  The following error was produced: dpkg: dependency problems prevent configuration of zoom:  zoom depends on libgl1-mesa-glx; however:   Package libgl1-mesa-glx is not installed.  zoom depends on libegl1-mesa; however:   Package libegl1-mesa is not installed.  zoom depends on libxcb-xtest0; however:   Package libxcb-xtest0 is not installed.  I then tried to update the individual packages specified herein.  However, each one of these packages has a long list of other packages that it is dependent upon.  So, I think my approach is incorrect. Does anyone here have a way to get Zoom's video client to install and function correctly on a machine with an Nvidia GeForce GTX 1050Ti GPU, Nvidia's 450.57 proprietary drivers and Ubuntu 20.04 LTS? Thanks


How can I disable the Timeline in Windows 10 April 2018 Update?

The Windows 10 April 2018 Update includes a new feature called Timeline which tacks the activities and allows you to see what you have done earlier, sends it to Microsoft servers, so that you can resume work on a 2nd device, which is connected to the same Microsoft account when you press the Tasks View button in the taskbar:    How can I disable the Timeline because I don't want that my activity gets tracked?


I am trying to explain physically what is happening in the picture below:    My gut explanation is that we are observing the reflection of a cone of light emanating from the moon, it explains the form of this reflection which looks like a cross section of a cone but I'm not convinced with this explanation.  I know this is supposed to be easy but, it bugs that I am not able to have an answer. Do you have a more convincing physics explanation?


Show Files and Folders Sorted by name NOT Folders First then Files

Is there any way to make Windows Explorer list the Files and Folder together and not Folders First?  So Folders and Files are sorted together by file name:  Antelope[dir] Antelope.txt Badger[dir] Badger.txt .... Zebra[dir] Zebra.doc


$(a_n)$ is a convergent sequence in $\mathbb{R}$ with infinitely many positive and negative elements. Show that $(a_n)$ is a nullsequence.

The definition for a null sequence is following:  $\forall \epsilon > 0, \exists n_0 \in \mathbb{N}, \forall n \geq n_0: |a_n -0|< \epsilon  $  We only know that the sequence is convergent and that there are infinitely many positive elements. How can I prove that $a_n$ is a null-sequence with my definition?


How does gravity cause acceleration? Also what means spacetime?

Since gravity only curves spacetime, how does it give kinetic energy to an object eg when an object falls to the ground. Since it only curves spacetime we shouldn't move towards it without kinetic energy. So when an object goes up why does it come down?


Show that $\frac{X-\mu}{\sigma}\sim N(0,1)$ using moment functions

Let $X\sim N(\mu,\sigma^2)$. Show that $Z=\frac{X-\mu}{\sigma}\sim N(0,1)$ using moment generating functions. \begin{align*} M_Z(t)&=M_{\frac{X-\mu}{\sigma}}(t)\\ &=M_{X-\mu}\left(\frac t\sigma\right)\\ &=e^{-\mu t}M_X\left(\frac t\sigma\right)\\ &=e^{-\mu t}\cdot e^{\frac{t\mu}{\sigma}+\frac{t^2}{2}}\\ &=e^{-\mu t+\frac{t\mu}{\sigma}+\frac{t^2}{2}} \end{align*} I'm not sure how to conclude that $Z\sim N(0,1)$.


Making 3 points stick on a plane / flag with wind

I have a flag I want to waft in the wind. I imported the shape as an SVG from Adobe Illustrator.  I converted the mesh to a curve.  It wouldn't let me make some subdivisons but it still seems to work with the cloth property.    When I press play, you can see the structure of the flag stops.  How can I make those last 3 points intact? Also the fill colour seems to have disappeared, do you know why and how I can bring it back?    Thanks  Steve  File here:


Do we have any idea why Planck's constant has the value it has?

Since $h$ seems to relate to a fundamental unit of quantization, it only seems right that we should have an idea of why it has the value it has. What do we know?  I understand that to some extent the precise values of universal constants are arbitrary, but when I look at the Bohr model, I see that the angular momentum of electrons comes in discrete levels that appear to be directly proportional to Planck's constant. Which suggests to me that there is something special about this number.


Prove $\lim_{(x,y)\to (0,0)} \frac{x^2 y^3}{x^4 + y^4} =0$ without $\varepsilon - \delta$.

Unlike  I would like to avoid the $\varepsilon - \delta$ criterium.     Prove $$\lim_{(x,y)\to (0,0)} \frac{x^2 y^3}{x^4 + y^4} =0 \,.$$   Approaching this limit from $y=0$, $x=0$, $y=x$, $y=x^2$ etcetera all yields 0 as value, so my proposal is that this limit is indeed 0.  I have been able to solve most similar limits so far by finding some convergent upper bound for the absolute limit, but with this one the difference between the numerator and the denominator is so small I can't find anything to fit inbetween. For example, $(x,y)\to(0,0)$, $$ \left| \frac{x^2 y}{x^2 + y^2} \right| \le \left| \frac{(x^2 + y^2)y}{x^2 + y^2} \right| \to 0 \,. $$  Also,  and  contain some helpful hints.


Applicable Group Problem Involving Modular Arithmetic

Question: Show that $(5, 15, 25, 35)$ is a group under multiplication modulo 40.   So I first decided to make a Cayley Table that looks like this:     I apologize that I do not know how to make a Cayley Table in MathJax.   So I know it is closed, and associative because of multiplication inheritance.  I am just confused about the identity element. I could use some descriptive advice about how you find it. I know once you find that, you can use the table to find inverses of each.


Real world uses of hyperbolic trigonometric functions

I covered hyperbolic trigonometric functions in a recent maths course. However I was never presented with any reasons as to why (or even if) they are useful.  Is there any good examples of their uses outside academia?


Cannot use WiFi on Linux, Alienware 14 laptop

I recently got an alienware 14 laptop, and want to use Linux on it. I installed Ubuntu 14.04. However, I found that the wireless adapter does not work - Killer Wireless-n/a/ac 1525 Wireless Network Adapter.  So I purchased usb wifi adapter. Now I can connect to Wifi, but extremely unstable. After I have been connected for about 5 minutes, it still says connected, but cannot use internet. I tried to ping a random address, there is simply no echo, rather than no response - nothing echoes in my terminal. If I disable wifi and enable again, sometimes it will connect for another 5 minutes, sometimes just fails to connect.  I thought it was a problem of the usb wifi adapter, so bought another one for raspberry pi, but exactly the same problem.  I thought it was a problem of my Linux distribution, so I tried Ubuntu 12.04, Linux Mint, Fedora 23. All have the same problem.  Still cannot use WiFi on Linux, on my ALienware 14 laptop. Feeling frustrated. Anyone could help? Thanks.  Results of lspci -knn | grep Net -A2:      03:00.0 Network controller [0280]: Qualcomm Atheros Device [168c:003e] (rev 20)     Subsystem: Bigfoot Networks, Inc. Device [1a56:1525]     04:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS5227 PCI Express Card Reader [10ec:5227] (rev 01)     Subsystem: Dell Device [1028:0685]


How can I see the *real* raw values from a raw file?

I want to do some performance tests concerning what the ISO setting "really does", whether ETTR makes sense, measure the noise, etc. on my camera.  Rather than look at the pixels after it's been Bayer decoded, mapped, reconstructed, etc. I'd like to look at the real raw data; that is, the sensor sample values.  Ideally it would be three matrices for R, G, and B components (with G being twice the size in both dimensions).


How do I run a script in the background and leave it running when I log out?

Possible Duplicate:          I have a bash script that runs Gaussian, a chemical structure calculator, which spends a couple days toying with a molecule.  It runs on a Linux box that I load the input files and said script on to, then I (am supposed to) run it, wait a while, hope the program didn't crash, and log back on to collect the result.  Somewhat of a *nx newbie, but I can't seem to figure out how to set the script running and disconnect, while letting it continue on.  ./jobscript   appears to block until it's done, and if I disconnect it terminates  ./jobscript &   doesn't block, I can see it running in top, so I thought it was OK, but on logging out it apparently killed the program.  How do I set the thing to run and stay running, even if I logout?


How can the speed of sound increase with an increase in temperature?

I was reading a textbook. I found that it was mentioned the speed of sound increases with increase in temperature. But sound is a mechanical wave, and it travels faster when molecules are closer.   But an increase in temperature will draw molecules away from each other, and then accordingly the speed of sound should be slower. How is it possible that the speed of sound increases if temperature increases? What is the relation of speed of sound and temperature?


Ubuntu 16.04 Complicated Interface Names

I'm trying to figure out how to restore the simple interface names in Ubuntu 16.04. I.e. enp3s0 renamed to eth0.   I have tried to modify the GRUB configuration. I have tried editing /etc/udev/rules.d/10-network.rules, but both methods did nothing for me. Help is greatly appreciated.   /etc/udev/rules.d/10-network.rules: (I hid the mac address names.)  SUBSYSTEM=="net", ACTION=="add", ATTR{address}=="XX:XX:XX:XX:XX:XX″,KERNEL=="enp0s0″, NAME="eth0″ SUBSYSTEM=="net", ACTION=="add", ATTR{address}=="XX:XX:XX:XX:XX:XX″,KERNEL=="wlx02c5c1866772″, NAME="wlan0″  And I changed this line in the GRUB configuration (/etc/default/grub) ...  GRUB_CMDLINE_LINUX=""   to look like this:  GRUB_CMDLINE_LINUX="net.ifnames=1"


How can I lock my screen in Gnome 3 without GDM?

There is no "Lock" option showing up in the user menu, and the standard shortcuts (Ctrl+L or Ctrl+Alt+L) don't do anything.  I'm running Fedora 19 with Gnome Shell 3.8.3, and XDM 1.1.11.  I'm using XDM because of broken XDMCP support in GDM - but before I upgraded to Fedora 19, I did have the lock option, even when using XDM.     I've posted an answer reflecting the results of my own research. It basically says that it's not possible to have screen-lock integrated into Gnome 3.8 without running GDM.      I really hope there's a better answer available though - so please add your own answer if there's any way to do this that I overlooked.


Is it possible to show numbers for each app on the task bar?

I like the fact that I can launch apps on the task bar by using hot keys such as Win + 1 to 9.  But, is it possible to show those numbers on the task bar?


Please ditch the five-minute window on comment editing

Bravo for allowing comment editing, but what's the explanation for enforcing a five-minute window?  I think this might be over-engineering. If I have a spelling mistake or an inaccuracy I'd like to fix, I don't think the fact that five minutes has elapsed should prevent me from fixing it.  Further, if you are worried people will edit their comments in a way that makes the comment thread nonsensical, they can already do this by deleting their comment. So, limiting the ability to edit isn't really helping much in that regard.  Update  If people don't like this idea, I'm definitely open to hearing your reasons. For now, it seems like an unnecessary limitation of a quite awesome feature.  Update 2  Regarding John's scenario...     Me: Obama is cool!   You: You are right, man!      My edit: Obama is an idiot!   You: You are right, man!   ...this problem can still occur with deletions...     user1: Obama is cool!   user2: No, McCain is cool!   you: You are right, man!        user1: Obama is cool!   ---- deleted -----   you: You are right, man!     So, yes, editing could be abused as you suggest, but discontinuities can occur already because of deletions (and as someone else mentioned, because upvoted comments get prioritized upward).  As for Jeff's argument about rate limiting, I agree that is important, but I don't understand why you can't just use a CAPTCHA to prevent too many edits in a short period of time.


Why does `printf "%s"` concatenate two following strings together?

$ printf "%s" a b ab$ printf "%s%s" a b ab   I have some problem understand the format specifier for printf. If I am correct it is mostly the same as those for strings in the C programming language.  Why does the format specifier %s concatenate the two following strings together?  Why does  %s not mean that there is only one string to substitute it, and ignore the remaining string?  Why are the results for two strings under %s and under %s%s the same?


Arguing on dimensions of logarithms and exponentials

Suppose you have some physical quantity $x$ of dimension $l$. We all know that the dimension  of $x^2$, for example, will be $l^2$, and that of $\dfrac{1}{x}$ is $l^{-1}$. However, what will be the dimensions of $ln(x)$ and $e^x$ ?  I think I've never encountered such a case before, wherever I found $ln(x)$ or $e^x$, $x$ had no dimensions. I don't know if we can ever have a case where $x$ possesses a dimension.  Supposing this case exists, I may be able to prove that $ln(x)$ has no dimensions, as $d(ln(x))=\dfrac{dx}{x}$ which is a dimensionless quantity for any $x$, but I can prove nothing for exponentials, and I'm not even sure that this is a valid argument. However, there is a different problem with exponentials:  $e^x.e^y=e^{x+y}$, how can you sum $x$ and $y$ if they have different dimensions ?


"Are they American?" or "Are they Americans?"

What is the difference bewteen     Are they American   and     Are they Americans?


What does the status "Waiting for reviewer assignment" mean?

I submitted my revised manuscript to a mathematical journal since 12-04-2017. The status is "Waiting for reviewer assignment" since 24-4-2017. What does it mean? Have the reviewers started working on my manuscript yet?.


I am making a dictionary/translator but I want to let the user write, 'hello' and 'Hello' and still receive the result 'Ronne'.  print ("English to Exrian Dictionary") search = input("Enter the word you would like to translate: ")  if search == "Hello":     print ("Ronne") elif search == "Bye":     print ("Zio") else:     print ("No matches were found for '" + search + "'")


Finding real life width and height knowing camera properties and distance to object

I'm trying to basically find the width and height of someone's face I know the following:  distance from face to camera in mm the sensor height in mm the focal distance in mm distance in pixels distance between my points Height/Width of image in pixels  How can I accurately get the width and hight measurements in MMs. I took a look at this. Could I use it for width measurements as well? Is there a more accurate way to go about doing it?


How to export materials from Blender for use in another 3d software such as Houdini or Unity?

So I made a model with a material that has a complex node system and I want to export that material so that I could apply it to the model. Is there a way to do such a thing?


In the last episode of season 9, why did the Doctor need to erase this person's memory?

In the last episode of season 9, the Doctor said he needed to erase Clara's memory. And after Clara said that she reversed the Doctor's device, he used it anyway. Why did someone (the Doctor or Clara) have to lose their memory? And how much of the Doctor's memory was erased?


What's hook to use immediately after a user is authentcated

Does anyone know the add_action() hook to use immediately after a user is successfully authenticated.  Hook Test based on @mmm's answer  I ran this test from my mu-plugins.php file:  function check_for_superAdmin() {     if ( is_super_admin() ) { echo 'I\'m a Super Admin !'; exit; } } add_action( 'wp_login', 'check_for_superAdmin' );   the check_for_superAdmin() function works but the is_super_admin() function does not. I may need to pass a parameter in there. Checking....


I just installed the latest Desktop OS Ubuntu 16.04.03 LTS. After install, I cannot connect to the internet.  I tried to ping google.com and it says ping: unknown host google.com.  I tried to ping google's IP 172.217.25.14 and also their DNS 8.8.8.8 and the connection is successful.  I think the problem is with my DNS. I already reinstalled Ubuntu with the same results. I can also Ping and even browse my local router at 192.168.1.1. The machine has a valid IP address (from the router). And there is not problem with my internet (there are other computers that are connected to the network and can connect to the internet).  I've got this installed on an ASUS P8Z68-V PRO/GEN3 motherboard. I'm using the onboard LAN.  I cannot browser, the system cannot update because it cannot connect to the internet. Again I think this is somewhere around name resolution but I just can't put my finger on it.  Thanks for the help.


Why do all atoms follow the same $n$ and $\ell$ quantization conditions as hydrogen?

The quantum state of an electron in a hydrogen atom is specified by 4 quantum numbers: $n$ , $\ell$, $m_\ell$, $m_s$ which can take the following values: $$n =  1, 2, 3, ... $$ $$\ell = 0, 1, 2, 3, ..., n-1 $$ $$m_\ell =  -\ell , -(\ell-1), ... , (\ell-1), \ell$$ $$m_s = +\frac{1}{2} ,-\frac{1}{2} $$ If I'm not mistaken, the condition that specifies that specifies the highest $\ell$ value can be found when solving the radial Schrödinger equation.  Therefore, why can we also apply the same rules for determining the electronic configuration of an atom with many electrons? Wouldn't the potential energy term in the radial equation be altered by the presence of all of the other electrons, hence resulting in a different relationship between $n$ and the highest possible value of $l$?


Short story about an atheist dying, being resurrected by God in heaven to perform a mission

I've read a short story, probably online, about an atheist who dies, and to his own surprise, is met by God.  The story is told from the perspective of the atheist, who learns that he was chosen because of his personality and way of thinking, and is asked to help finding a solution. In the story, it turns out that although God has complete control and understanding about our universe, there is something even He cannot do: affecting Himself, and His own eternal existence. Being curious about it, (or maybe hinted of God wanting to actually commit suicide, I don't remember), God gives the mission to the atheist to help in unlocking the limits of His own existence.  The atheist eagerly accepts the mission, the story ending with something in the like of it being a hard task to accomplish, but that's not a problem, he has all eternity to do it.


Strptime open source code not implementing

I am trying to convert a string into time format. As I read here on stackoverflow, the discussion of converting a string into time format. The function strptime() has been used for the same. I am also using the strptime() in my program in C, in windows. I tried to copy the open source strptime code from the following link in my program, but there are too many headerfiles missing. I created those headerfiles too, but still the code is not working and giving many warnings.  Please help.    Thanks much.


Search for all files with a .sql extension in folders and sub folders

I want to search for all files with the .sql extension in folders and sub-folders (recursive).  How can I do this?


How to get a list of highest-voted answers?

I can sort the list of questions based on the number of votes and on tags. Can I do the same thing for answers?


In practice with C++, what is , what are , how are these implemented in a program and what are the benefits of using RAII with smart pointers?


Which method to use to remove correlation between independent variables comprising of both categorical and numerical variables?

The independent variables in the dataset contains categorical variables such as  Gender ( 2 levels) Mode of Shipment ( 3 levels) Product Importance ( 4 levels)  and Numerical Variables such as  Customer care calls Discount Offered Package weight  How do I find the correlations between these variables?  Converting categorical variables in to dummy variables and then using pearson correlation? What if the dummy variable categories also shows correlations too? such as correlation between Mode of shipment categories, Flight, ship, road? Do I need to remove the highly correlated dummy variable category with the other mode of shipment category? or doing separate correlations between numerical variables using pearson correlation, and for categorical variables using chi sq statistics?  How to go about it? Thank you! It's a long question, but really need this clarity. Would appreciate any additional links too. Thanks again!


Problems when trying to upgrade from 10.04 to 12.04

When I was trying to upgrade my server from ubuntu 10.04 to 12.04 I was facing problems with some packages. It was saying,  sudo apt-get dist-upgrade Reading package lists... Done Building dependency tree Reading state information... Done   You might want to run `apt-get -f install' to correct these.     The following packages have unmet dependencies:       gcc-4.4: Depends: gcc-4.4-base (= 4.4.7-1ubuntu2) but 4.4.3-4ubuntu5.1 is installed                Depends: cpp-4.4 (= 4.4.7-1ubuntu2) but 4.4.3-4ubuntu5.1 is installed                Depends: binutils (>= 2.20.1-15~) but 2.20.1-3ubuntu7.1 is installed                Depends: libgcc1 (>= 1:4.4.7-1ubuntu2) but 1:4.4.3-4ubuntu5.1 is installed                Recommends: libc6-dev (>= 2.13-0ubuntu6) but it is not installed       libnih-dbus1: Depends: libnih1 (= 1.0.3-4ubuntu9.1) but 1.0.1-1 is installed       libnih1: Depends: libc6 (< 2.12) but 2.15-0ubuntu10.5 is installed     E: Unmet dependencies. Try using -f.


What would be the correct use of will & would in these sentences?  1) What will happen if I say to my boss that I will not come tomorrow?  2) What will happen if I would say to my boss that I will not come tomorrow?  3) What will happen if I will say to my boss that I will not come tomorrow?  4) What would happen if I would say to my boss that I will not come tomorrow?  There are four sentences which one should I use and in which situation?


Fetch the path of the file I just clicked to open with a java application (jar executable)

I have this simple program that does nothing:  class ShowTheNameOfTheFile{   static public void main(String[] argv){    } }   I compile it as ShowTheNameOfTheFile.jar and configure my Windows machine to open all txt files with it.  Now, when I click a txt file it will open my ShowTheNameOfTheFile.jar program.  In java, how can I know with txt file has opened the ShowTheNameOfTheFile application?


Proof by Induction for a $f_3 + f_6 + · · · + f_{3n} = \frac{1}{2} (f_{3n+2} - 1)$

The Fibonacci numbers are defined as follows: $f_0 = 0,\ f_1 = 1$, and for $n ≥ 2,\ f_n = f_{n−1} +f_{n−2}$. Prove that for every positive integer $n$,  $$f_3 + f_6 + \ldots + f3_n = \frac{1}{2} (f_{3n+2} - 1) $$  Here are my steps:  Basis Step:  For $n ≥ 1$  $f_{3\cdot1} = \frac{1}{2} (f_{3\cdot 1+2} - 1) $  LHS $= f_3 = 2$  RHS $= \frac{1}{2} (f_5 - 1) =  \frac{1}{2} (5 – 1) = 2$  Induction Step:  Assume that $f_3 + f_6 + \ldots + f_{3n} = \frac{1}{2} (f_{3n+2} - 1)$  for some $n ≥ 1$.  Show that $f_3 + f_6 + \ldots + f_{3n}  + f_{3(n+1)} = \frac{1}{2} (f_{3(n+1)+2} – 1)$.  $$\frac{1}{2} (f_{3n+2} – 1) = \frac{1}{2} (f_{3(n+1)+2} – 1) + f_{3(n+1)}\ \text{(Basis)}\\ \text{LHS}=\frac{1}{2}(f_{3n+5}-1)+f_{3n+3}$$  I don't know how to proceed further. I understand what I have to do, but I don't know where to start reducing it using the fib definition.


How to position two figures side by side with custom alignment?

I would like to put two figures side by side such that they are centered on the page and have an arbitrary (given) space between them. Although there are a lot of similar questions here, none has given me the desired result.  I have found that using the following code allows the placement of two figures side by side with the possibility of having an arbitrary space between them. However, as it can be noticed from the picture, because the widths of the pictures are higher than the line length, the right picture goes past the text, while the whole ensemble remains aligned with the text:  \documentclass{article} \usepackage[demo]{graphicx} \usepackage{caption} \usepackage{subcaption} \usepackage{lipsum}  \begin{document}      \lipsum[1-1]      \begin{figure}[h!]         \captionbox{This is a duck\label{fig2:a}}{\includegraphics[width=.6\textwidth]{duck.png}}%         \captionbox{This is a sparrow\label{fig2:b}}{\includegraphics[width=.6\textwidth]{sparrow.png}}     \end{figure}      \lipsum[1-1] \end{document}   The result is depicted below: (note that the code above will work but it will show black boxes instead of images because of the 'demo' option before the graphicx \usepackage parameter)    The problem is that I would like the image group to be centered on the page and overtake an equal amount the paragraph text on both sides.  Is it possible to achieve that from this code, or at least by maintaining the possibility of an arbitrary separation between the images?


How do I copy Word tables into Excel without splitting cells into multiple rows?

I have data in a Word table that includes line and paragraph breaks. When I copy the data into Excel, it splits each line and paragraph I want into multiple cells. How do I copy the data to Excel and keep the breaks?


What does the square root of minus $i$ equal?

Can you enter the rabbit hole recursively?  If the $ \sqrt{-1} = i $ then, what does $ \sqrt{-i} $ equal?


I cannot seem to get the wireless network card working on my lenovo y40. I am new to linux so I am pretty lost on how to fix this.  Here is the output of lshw -C network:  *-network                   description: Ethernet interface    product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller    vendor: Realtek Semiconductor Co., Ltd.    physical id: 0    bus info: pci@0000:03:00.0    logical name: eth0    version: 10    serial: f8:a9:63:31:30:fb    size: 100Mbit/s    capacity: 1Gbit/s    width: 64 bits    clock: 33MHz    capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation    configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full firmware=rtl8168g-3_0.0.1 04/23/13 ip=10.0.1.10 latency=0 link=yes multicast=yes port=MII speed=100Mbit/s    resources: irq:64 ioport:4000(size=256) memory:c0604000-c0604fff memory:c0600000-c0603fff  *-network DISABLED    description: Wireless interface    product: Wireless 3160    vendor: Intel Corporation    physical id: 0    bus info: pci@0000:04:00.0    logical name: wlan0    version: 93    serial: a0:88:69:8e:3e:1a    width: 64 bits    clock: 33MHz    capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless    configuration: broadcast=yes driver=iwlwifi driverversion=3.13.0-24-generic firmware=22.24.8.0 latency=0 link=no multicast=yes wireless=IEEE 802.11abgn    resources: irq:70 memory:c0500000-c0501fff   rfkill list all returns -  0: ideapad_wlan: Wireless LAN    Soft blocked: no    Hard blocked: yes 1: ideapad_bluetooth: Bluetooth    Soft blocked: no    Hard blocked: yes 2: hci0: Bluetooth    Soft blocked: no    Hard blocked: no 3: phy0: Wireless LAN    Soft blocked: no    Hard blocked: no


strange errors going on in a \end{equation} line

I was compiling a document containing the following lines (132 to 135):  \begin{equation}  \label{shiperfina1}  H_{sh}=\sum \limits_{j=o}^{n} \vec{S}\cdot\textbf{a_j}\vec{I_j}  \end{equation}   In the 135 line the following errors show up: missing $ inserted and missing } inserted. Furthermore, this errors apears several times in the log (26 times to be exact).  In the previous lines it's everything correct.  What do I do?   Thanks.


How can I tell at a glance which synonyms I can vote on?

Inspired by the brave efforts in  I went to check out the voting on synonyms.  I'm eligible with respect to reputation, and I'm certain I'm eligible to vote on some synonyms, but there seems to be no way to tell which ones without going back and forth between my profile and the synonyms screen (or attempting to vote on each of them and getting the rejection notice).  Is there a quicker way to tell at a glance on which synonyms I can vote?


Why does the Boltzmann factor $e^{-E/kT}$ seem to imply that lower energies are more likely?

I'm looking for an intuitive understanding of the factor $$e^{-E/kT}$$ so often discussed. If we interpret this as a kind of probability distribution of phase space, so that $$\rho(E) = \frac{e^{-E/kT}}{\int_{0}^{\infty}e^{-E'/kT}dE'}$$ then what, precisely, does this probability correspond to? Is its physical significance obvious? Specifically, why is it largest for energies close to zero?  Edit: I'd like to know how it is possible that for increasing $T$ the lower energy states grow more populated. The naive thing to think is "If I stick my hand in an oven and turn up the temperature, I'm assuredly more likely to be burned." This raises the question, exactly what does it mean for the lower energy states to grow more populated relative to the higher energy ones?


Contour method to solve $\int^\infty_0\frac{\ln(1+x)}{1+x^2}\,dx$

Prove the following using complex analysis   $$\tag{1}\int^\infty_0\frac{\ln(1+x)}{1+x^2}\,dx=\frac{\pi}{2}\ln(2)$$  I found this problem in Schaum's outlines of complex variables.   I thought that we could solve the problem using a similar method to evaluating   $$\int^\infty_0\frac{\ln(1+x^2)}{1+x^2}\,dx$$   Where we integrate the function  $$f=\frac{\log(1-iz)}{z^2+1}$$  around half a circle in the upper half plane and chosing an analytic branch of the logarithm in the region.   I spent so much time on (1) without success.


I want to upgrade my disk from MBR to GPT, and I tried using Windows' MBR2GPT.EXE tool to do the job. I used Windows' DISKPART tool to identify the disk I want to convert. However, this happened:  C:\WINDOWS\system32>MBR2GPT.EXE /convert /disk:0 /allowfullos  MBR2GPT will now attempt to convert disk 0. If conversion is successful the disk can only be booted in GPT mode. These changes cannot be undone!  MBR2GPT: Attempting to convert disk 0 MBR2GPT: Retrieving layout of disk MBR2GPT: Validating layout, disk sector size is: 512 bytes Disk layout validation failed for disk 0 MBR2GPT: Conversion failed   and the conversion failed. Using Diskpart again, I get the following output:  DISKPART> list disk    Disk ###  Status         Size     Free     Dyn  Gpt   --------  -------------  -------  -------  ---  --- * Disk 0    Online          465 GB      0 B   Disk 1    Online         3841 MB   960 KB  DISKPART> select disk 0  Disk 0 is now the selected disk.  DISKPART> list partition    Partition ###  Type              Size     Offset   -------------  ----------------  -------  -------   Partition 1    Primary            100 MB  1024 KB   Partition 2    Primary            464 GB   101 MB   Partition 3    Recovery           813 MB   464 GB   Partition 4    Recovery           511 MB   465 GB   Looking at the partitions on disk 0, there are 2 primary partitions and 2 hidden ones, I read  that the partitions might have something to do with the conversion failing, so I believe this is the culprit. If anyone could offer help converting my disk, that would be greatly appreciated.


I was learning about the proc filesystem mechanism and I randomly tried to check the file descriptors of bash itself. Can someone explain what the file descriptor number 255 doing here (like I understand what 0,1,2 mean but I have no idea what 255 is in this case) ?  sc@HP-ProBook:~$ ls -l /proc/11783/fd total 0 lrwx------ 1 sc sc 64 Feb 23 15:40 0 -> /dev/pts/2 lrwx------ 1 sc sc 64 Feb 23 15:40 1 -> /dev/pts/2 lrwx------ 1 sc sc 64 Feb 23 15:40 2 -> /dev/pts/2 lrwx------ 1 sc sc 64 Feb 23 15:48 255 -> /dev/pts/2


How does one prove that an orbit of a satellite around a planet of significantly greater mass than the satellite is a conic section (i.e. an ellipse, circle, hyperbola, or parabola)?   Also, there is also the case of a degenerate orbit, which we have for example when the satellite starts at rest with respect to the planet, and the satellite moves along a straight line towards the center of the planet.   By the way, I realize this may be an extremely tough question, because I have seen once before the derivation with vector calculus that bounded orbits are ellipses, and it is definitely quite involved. As such, you may wish to provide an outline of how might this be done (does one have to consider bounded and open orbits separately, for example?) and omit the math.  Also note that I assume the satellite is small compared to the planet because I don't want to add the complexity of a two body-system orbiting around the center of mass just yet!


Should I use my kit lens at max aperture or max zoom for shallow depth of field?

I have the Nikkor 18-55mm f/3.5-5.6g vrii lens using it on the D3300. I have been trying to create some bokeh effect using this lens (I know it isn't a great lens for bokeh). The thing I was wondering was which setting will give me good bokeh.  1). Zooming at 18mm and keeping aperture the widest? (Sacrificing the max zoom for the lens) 2). Zooming at 55mm, this eventually wouldn't have widest aperture.  I know that keeping the aperture the widest and max zooming the lens combined gives you great bokeh. I'd like to know what I could do in my case to achieve the best possible blur.


Why there are more games in windows than linux?

I cannot comprehend why there are so many games available for windows and so few for linux in comparison. Why is the main reason, is it a technical or business reason ?  Are Windows libraries (directx) better or is it because of the driver support ? Linux have some great libraries like Allegro , SDL and LibGlut. And Android is Linux after all.  Given all that Why are more games in windows than linux ?.


I'm trying to set 'orderby = none' to my loop but it is not working. Here's my code:  $query = new WP_Query(array('showposts'=>2, 'post__in' => array(99,4,5,2,8,55), 'orderby'=>'none'));   Could anyone help me?  Thanks.


Is it possible to use Wubi for Ubuntu 13.04? I read that it will not be supported in the official release due to some problems. Is this going to change in the future, and can we expect to see a future release with support for 13.04?


How to recover .ibd and .frm files in MySQL

I am developing a Java application with MySQL 5.6.13. A few days earlier I purchased a new laptop. I forgot to create a dump of application from previous laptop and instead I copied folder of my database(.ibd and .frm files) from datadir, when I installed MySQL 5.6.13 in new machine, and I had pasted my database(.ibd and .frm files) into datadir. The server is running fine. But in MYYOG IDE, when I open any of tables I am getting this error:


Copying a float environment with modified name and float counter

Is it possible to copy a float environment, such as e.g. the figure environment, to create a new environment, with identical properties except for the name (e.g. create a 'Ancillary Figure' instead of 'Figure' name) and float-counter?   In short, I would like to have a situation where I could have two distinct but concurrent figure-environments, one for "primary" figures and one for "auxiliary/ancillary" figures.   I expect that the  package would be handy here, but cannot see how to copy an environment.


I don't want to start a religious war or anything, but I do have questions about a few languages.  I have a project that was originally done in Java and was about 75% complete, but now it has to be redone, the conditions are quite different than they were 4-5 years ago when the previous code was written.  While I've been doing research, I'd like to get some background on the different languages at this point so I have a good idea what I can focus on and what I can (likely) ignore.  I see, in the FAQ, that open ended questions like this are discouraged.  But I don't know of other programming forums that aren't focused on a specific language.  So are there appropriate ways to ask such a question?  (Actually it's several questions about C++, Python, Perl, Java and cross platform stuff.)


How to get smooth scrolling movement with magic mouse

I have a new Ubuntu-Mate and I'm taking advantage of the Apple Magic mouse and keyboard.  The Magic mouse, in the OSX has a smooth scroll... like a roll, there is a scrolling control depending on the strength of the finger movement.  I would like to have this behaivour in Ubuntu, but I can't get information about this ( I've found information about change direction but not about "rolling movement")  The aplication "naturalscrolling" seems than doesn't exist anymore.  How can I achieve this?  Thanks


Why is my Java method changeVolume() return the same results despite the changes in value?

My volume variable does not change when I run the code.  I tried changing the order of the code and new variable names, but the output doesn't change. The changeVolume() function doesn't do what it supposed to be doing.   Please help me figure out why it won't work. Bellow is my code and screenshots of me running it:  import java.awt.Color; public class HeadPhone{ //Three constants public static final int LOW = 1; public static final int MEDIUM = 2; public static final int HIGH = 3;  //a private int data filed for volume     private int volume; //and a pluggedIn value private boolean pluggedIn; //A private String data field for manufacturer private String manufacturer; //A private Color data field private Color headPhoneColor; //A private String field  private String headPhoneModel;  //setters and getters for the declared values public void setVolume(int volume){     this.volume = volume; } public int getVolume(){     return volume; } public void setPluggedIn(boolean pluggedIn){     this.pluggedIn = pluggedIn; } public boolean getPluggedIn(){     return pluggedIn; } public void setManufacturer(String manufacturer){     this.manufacturer = manufacturer; } public void setHeadPhoneColor(Color headPhoneColor){     this.headPhoneColor = headPhoneColor; } public Color getHeadPhoneColor(){     return headPhoneColor; } public void setHeadPhoneModel(String headPhoneModel){     this.headPhoneModel = headPhoneModel; } public String getHeadPhoneModel(){     return headPhoneModel; }  //A no argument default constructor public HeadPhone(){     volume = MEDIUM;     pluggedIn = false;     manufacturer = "Apple";     headPhoneColor = Color.WHITE;     headPhoneModel = "Mic-Enabled";         }  //toString method that returns  //the current set of headphones     public String toString() {     String headPhoneColorString = "";      if (headPhoneColor == Color.RED){         headPhoneColorString = "Red";     }     if (headPhoneColor == Color.BLUE){         headPhoneColorString = "Blue";     }     if (headPhoneColor == Color.BLACK){         headPhoneColorString = "Black";     }     if (headPhoneColor == Color.CYAN){         headPhoneColorString = "Cyan";     }        if (headPhoneColor == Color.YELLOW){         headPhoneColorString = "Yellow";     }     if (headPhoneColor == Color.WHITE){         headPhoneColorString = "White";     }      String pluggedUnplugged = (pluggedIn == true) ? "plugged in" : "unplugged";      return "\n\n Volume Set To: " + volume +             "\n Headphone set is: " + pluggedUnplugged +            "\n Manufacturer: " + manufacturer +            "\n Headphone Color: " + headPhoneColorString +            "\n Headphone Model: " + headPhoneModel;                } //a changeVolume method to adjust headphones volume public void changeVolume(int volume) {     if (volume <= LOW){         volume = LOW;     }else if (volume >= HIGH){         volume = HIGH;     }else{         volume = MEDIUM;     }                 }             //main class     public static void main(String[] args) {     HeadPhone defaultHeadphoneSet= new HeadPhone();             System.out.println(defaultHeadphoneSet);      HeadPhone set1 = new HeadPhone();     set1.changeVolume(HIGH);     set1.setPluggedIn(true);     set1.setManufacturer("Beats");     set1.setHeadPhoneColor(Color.RED);     set1.setHeadPhoneModel("Wireless");     System.out.println(set1);      HeadPhone set2 = new HeadPhone();     set2.changeVolume(HIGH);     set2.setPluggedIn(true);     set2.setManufacturer("BOSS");     set2.setHeadPhoneColor(Color.BLACK);     set2.setHeadPhoneModel("Noisecancelling");     System.out.println(set2);      HeadPhone set3 = new HeadPhone();     set3.changeVolume(1);     set3.setPluggedIn(false);     set3.setManufacturer("SkullCandy");     set3.setHeadPhoneColor(Color.CYAN);     set3.setHeadPhoneModel("Taptic");     System.out.println(set3);         }     }


Why do large angular displacements affect the amplitude of a simple pendulum?

I was conducting an experiment involving the effect of large angular displacements (10°, 20°, ... 90°) on the amplitude of a simple pendulum. So far, I have found that the period of the pendulum varies according this equation:  \begin{align}T&=  2π\sqrt{\frac {l}{g}} \left(1 + \frac{1}{16} θ^2 + \frac{11}{3072} θ^4  + \frac{173}{737280} θ^6  + \frac{22931}{1321205760} θ^8\right. \\ &\left.\qquad\qquad+   \frac{1319183}{951268147200} θ^{10} + \frac{233526463}{2009078326886400} θ^{12} + …\right) \end{align}  Essentially, period increases with increasing angular displacement. However, I don't really understand why the period varies in this way. Could someone explain this to me without the use of math (no small angle approximations/Taylor series)?   For example, in this way: Although the pendulum accelerates for a longer period of time and has a greater maximum velocity, the additional distance it has to travel is greater than what its larger acceleration and maximum speed can make up for (this is just my guess).


When wiring a switch, should I break the neutral or power wire?

My husband has always wired a switch to break the neutral wire to turn a light on and off.  I can remember for 40 years he has said to "break the neutral".  However, our son worked as an electrician for 2 years and he said you always "break" the "power" wire (black one)  Who is correct?  Thank you!!


Email notifications for new questions matching specific tags

Is there a way to configure your Stack Overflow account so that you receive notification emails when posts are made to specific tags?    Or do you simply have to log on to see new posts?


something the matter (strange word order: indefinite pronoun + noun)

:     1. There was nothing the matter with it when I lent it to him.      2. She had something the matter with her back.   :     3. There's something the matter with my eyes.   It's a strange word order for me.  Is there any rule of using "indefinite pronoun + noun"?  If there's an ellipsis, then what text is omitted?  Thanks!    My question has nothing to do with the question: . In that question a non-inverted word order is "Something is the matter." We see the verb "is" between "something" and "the matter". In my question there isn't any verb between them. I absolutely can't understand how someone could think that this is the same questions.


In first order logic, can an argument that has a conclusion that is necessarily false (e.g. It is raining and it is not) possibly still be valid?


I've looked around the web for a solution and have found numerous threads with different suggestions.  Most of which I've found has been using LUA on the resolver to return records. Other posts suggest using GEO-IP or Pipe backends. All of the content I've read have used   I am curious to know if it is possible, via LUA to change the Forwarder based on the network range rather than using LUA to store zone information.  If I can get logic similar to the following to work I should be all set:  if sourceip comes from (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) {      forwarder = 192.168.0.1; }else{      forwarder = 8.8.8.8; }   I don't see any examples of LUA from pdns that demonstrate changing any settings within PDNS itself, and am curious if that is even possible.


PHP Distance between two points latitude longitude

I am after a very simple distance between two 2D points function for PHP.  For example lat, lng of -50000.00,400.00. This is a flat surface, no need calculate for the earth circumference.  I have tried all sorts of solutions for this and none of them work correctly. I do not know why but when lat or lng is > ~240.00 the result starts going backwards as if the distance is too great to calculate. Even the online calculators fail to calculate a large distance.  Any help would be greatly appreciated.


Angular Velocity after a frictional impulse

I am modelling 2D physics collision into simulations. In Physics for Game Programmers, Grant Palmer book,    the velocity Vn1 after collision is mentioned to be independent of the friction coeff. between the surface.   for a sphere Vn1=5/7Vn0. But this holds to true only when the sphere is assumed to be  in pure rolling after the impact.  How can i determine the velocity of the ball for a sliding case as well. I have to use it in a physics simulation and the duration of impulse is not known. Is there any other way to determine it?


Possible Duplicate:          I've been  for maybe a year to get answers to questions I couldn't find on my own.  I always make an attempt first to find the answer on my own.  As of this posting, I've asked 14 questions.  I only once gave an answer, and it was to a non-technical question, and only because I was really bored and had too much coffee to drink.  I wasn't intending to answer any other questions in the future, because on on my best days I'm only a mediocre programmer, and there are some real geniuses here on StackOverflow who can answer other peoples' questions faster and more accurately than I can.  It actually is my nature.  I am an Aquarian.  We are asker-listeners.  Today I discovered Meta Stack Overflow and started browsing around.  I became familiar with the concept of the "Help Vampire".  I seem to qualify.  I continued reading more posts on the topic and got the distinct impression that people who only ask, and never answer, are less than welcome here, rather despised.  So, should I just go away?  Or should I start contributing answers just to have a answer-to-question ratio of 3-to-1 (I read somewhere that's the average) even though I am less than one eighth as knowledgeable as the 10K+ guys and gals?    Or should I continue as I have begun?  I mean, doesn't a 0-questions-asked user like Jon Skeet need a Blankman?  Yin and yang, you know?


Short story (Asimov?) involving incorporeal beings working on how to manipulate matter

Looking for a short story where two incorporeal beings meet, and one shows the other something they've been working on: the ability to manipulate matter. At the end of the story,   the character builds a replica of a human being, and it becomes clear the characters themselves were once human.  I thought this one was an Asimov, but my searching has proven fruitless so it's probably a completely different author.


What is the difference between the various image-stabilized Canon 18-55mm lenses?

I'm looking at buying a new 18-55mm lens as the one that came with my 4000D doesn't have image stabilisation, which I really need. It seems like canon have made many EF-S lenses over time that all seem to have the same features.  I won't be recording video on this camera so having silent auto-focus isn't important to me.


How to use another mirror with Macports?

I'm a newbie to Macports and I really wonder how I can change the default mirror to . What's more, when I use Macports to install softwares from source, it always downloads from  which is not available, and I want to use  instead. Can anyone help me? Thanks a lot.


Proof of matrix norm property: submultiplicativity

I've been searching for the definition of the submultiplicative (I think it has multiple names from what I've seen) property in proof form. Some books define it as part of the properties that define matrix norms, and some include it as an additional property. I still haven't been able to work it out for myself or find it anywhere.  Let $A$ and $B$ be $n\times m$ and $m\times l$ matrices respectively, prove that:  $$\begin{align} \|AB\| \le \|A\|\|B\|  \end{align}$$


List slicing within a certain length and outputting them as plain text

Let's say I have a list: newList = [0,1,1,0,1,0,1,0,1,0,1,0,1,0,1] I want to split and print them as generator with dimension of 5*3. Final result shall look like this: 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1  The result should not be a list, just plain text like such. Also, what should I do if I need to do it with different dimension (lets say 3*5 instead). I am trying to work out a code to perform this action on a list of arbitrary length and transform them to plain text of user-given dimension.


Let $G$ be a group. Say what it means for a map $\varphi: G \rightarrow G$ to be an automorphism. Show that the set-theoretic composition $\varphi \psi = \varphi \circ \psi$ of any two automorphisms $\varphi, \psi$ is an automorphism. Prove that the set $\mathrm{Aut}(G)$ of all automorphisms of the group $G$ with the operation of taking the composition is a group.   I have said: A map is an automorphism of a group $G$ if it is an isomorphism to itself.   a) For the next bit, I want to show if $\varphi, \psi$ is bijective, then $\varphi \circ \psi$ is bijective: For two elements $a, b \in G$ we have  $$\varphi \circ \psi (ab) = \varphi(\psi(ab)) = \varphi(\psi(a)\psi(b))$$  as $\psi$ is an isomorphism. Also, as $\varphi$ is an isomorphism, we have  $$\varphi(\psi(a) \psi(b)) = \varphi \circ \psi(a) \varphi \circ \psi(b)$$  Showing $\varphi \circ \psi$ is an isomorphism iff $\varphi, \psi$ are isomorphisms.  For the group bit, we want to prove the 3 group axioms.   1) Associativity: $\varphi \circ (\psi \circ \zeta) = (\varphi \circ \psi) \circ \zeta$. So for some $x \in G$, we get:  $$\varphi \circ (\psi \circ \zeta)(x) = (\varphi \circ \psi) \zeta(x) = \varphi(\psi(\zeta(x))) $$   2) Identity: If we let the identity automorphism, $e: G \rightarrow G$, be the map $e(x) = x$, then clearly we get that $e \circ \psi = \psi \circ e = \psi$.  3) Inverse: As the automorphisms are bijective (already proved) then we know that  by definition of a bijection, there is well defined inverse such that $\psi^{-1}: G \rightarrow G$ exists.  (Second edit to correct proof for inverse): For any two elements $a,b \in G$, we want to see if $\psi^{-1}(ab) = \psi^{-1}(a)\psi^{-1}(b)$. Apply $\psi$ to both sides gives us  $$\psi \circ \psi^{-1}(ab) = \psi(\psi^{-1}(ab)) = ab$$  Doing the same on RHS gives us $ab$ and so we have proved the inverse exists and is unique.  Is this right and enough to prove this?  EDIT: Actually, can I just say that by definition of two bijective maps, the composition is also bijective and this is enough?


the i need to find the exact area under tha curve of the function $f(x)=4+3x-x^2$ on the interval $[-1,3]$ using limits and a Riemann Sum. I have nothing started, because I am confused on where to start, and where I would need to go from there, I need help with the entire problem. I hope someone can help me! Thanks


Why does sunset over a body of water cause a path of light stretching towards the horizon?

Have you ever notice the sunset's image in the sea? It's like long light path to the end of the horizon! I've attached a sample of this:     How can we explain this? I know that it can happen even in wave less sea or lake! Why is this path so continuous? I expected that sea should act like a mirror!


multiple words connected using multiple hyphens or one?

There are many topics here related to multiple hyphen use, which seems to depend on various factors.        human-voice controlled system     human-voice-controlled system     human voice-controlled system      Which is correct? Typically, human voice when used without the word controlled, need not be hyphenated.         software and finite-state-machine -based approach   software- and finite-state-machine -based approach   software and finite state machine-based approach   software- and finite-state-machine-based approach   software and finite-state-machine-based approach      Which of the above are correct and incorrect, and why?


How to store and preserve film negatives and slides?

I bought 35mm dedicated film scanner (Nikon CoolScan III) and I'm planning to digitize old negatives and slides I found at home.  How should I store and preserve these slides and films after I cut them and scan? How to choose best negative pages/sleeves, binders etc. and what to avoid?


Is there a difference or pros and cons betweeen those variations?  int main(int argc, char **argv) { return 1; }  int main(int argc, char * argv[]) { return 1; }


Get terms that contain posts that in turn belong to other terms?

So I have custom taxonomy called "shape" and another one called "color". If I want to get the list terms under shape that contain posts that are also present in terms under color, how do I do that?   Example, I have a post under custom post type toy called Ball which is present in both shape Circle and color Red. I want to retrieve the term name Circle via $wpdb query. I'd like to emphasize that I want to retrieve the list of terms and not the posts.


Swap used even though most memory is "cached"?

I'm trying to make sense of this free -m output:               total       used       free     shared    buffers     cached Mem:          7971       7608        363          1         17       4703 -/+ buffers/cache:       2887       5084 Swap:          975        967          8   So swap is used even though only 3GB out of 8GB RAM is actually used by processes? Why does this happen, shouldn't the OS use less memory for fs cache instead of using swap?  OS is Ubuntu 14.04.3 LTS with default settings.


Looking for children's book, future archaeologists uncover modern-day items

About twenty years ago (so, late 90s, but the book could've been older) I remember my mother read me a book. The basic premise was that for some reason, modern society had collapsed, been destroyed, or otherwise been forgotten, and a new human civilization had developed. Humans from this far future then rediscovered various items from modern times and tried to interpret what they were used for; this book described their findings.   I remember this being a picture book, but not being very colorful. Possibly it was going for a sort of Victorian/Planet-of-the-Apes aesthetic. I recall the future society being less advanced than our own, and they ascribed religious significance to a lot of the things they found (and were generally wrong about everything). I think the idea of the book was to be satirical and/or humorous, but also as a young child I was freaked out by the idea of everyone dying in some cataclysm.   I'd like to find this book again because I think I'd more appreciate the humor and I want to see if it's still as unsettling as I remember, but I have no idea how to even begin to look for it.


Is the mean of two symmetric, independent random variables also symmetric?

Does a proof exist that the mean of two symmetric, independent random variables is also symmetric? Or is the conjecture false?  I would be interested to learn about references to this question, or perhaps a shown proof.


How to avoid the indentation made by \**displayskip?

I wrote a class file, but I found if I want to change the space between the math environment and text by the , the indentation appears in front of the 'abstract'. Here is the mwe,              \begin{filecontents}{mycls.cls}             \NeedsTeXFormat{LaTeX2e}             \ProvidesClass{mycls}             \LoadClass{article}             \newdimen\@bls             \@bls=\baselineskip             \renewcommand\section{\@startsection {section}{1}{\z@}%                                    {1.2\@bls  plus .3\@bls minus .1\@bls}%                                    {5pt\@afterindentfalse}%                                    {\sffamily\large\bfseries\raggedright}}             \newbox\absbox             \def\abstract{\lrbox\absbox\minipage{\textwidth}%             \sffamily%             \hspace{-\fill}\section*{\normalsize\noindent Abstract}\vskip -1.5mm\relax%             }             \def\endabstract{\endminipage\endlrbox}              \def\keywords#1{%             \gdef\@keywords{\begin{minipage}{\textwidth}{\normalsize\sffamily \textbf{Keywords}}\\ \parbox[t]{\textwidth}{#1}\end{minipage}}}             \let\@keywords\@empty              \def\@maketitle{{\noindent\usebox\absbox\par}             {\vspace{20pt}%             {\noindent\normalsize\@keywords}\par}{\vskip2em\relax}}             \end{filecontents}             \documentclass{mycls}             \usepackage{lipsum}             \begin{abstract}             \lipsum[1]             \end{abstract}             \keywords{Hello}             \begin{document}             \maketitle             \lipsum[1]             \begin{equation}\label{eq:test}             a^2+b^2=c^2             \end{equation}             \lipsum[1]             \end{document}    The class and code above gives    But if I add the code              \expandafter\def\expandafter\normalsize\expandafter{%                 \normalsize                 \setlength\abovedisplayskip{40pt}                 \setlength\belowdisplayskip{40pt}                 \setlength\abovedisplayshortskip{40pt}                 \setlength\belowdisplayshortskip{40pt}             }   in the class file, the output will be    Some space appears in front of the 'abstract' and 'keywords'.  I want to know where the space comes from and how to cancel it.


Find the cardinality of the quotient of $\mathbb R$ in respect to R

R is an equivalence relation defined as $xRy \Leftrightarrow a - b$ is an integer.  What is the cardinality of the quotient of $\mathbb R$ in respect to R? How would you prove it?  I thought about a bijection between $[0,1)$ to the quotient of $\mathbb R$ in respect to R, but can't figure out to prove it formally.


Let {G,∗} be a group with identity e and let a∈G be a fixed element in G with a≠e.  Define H={x|x∈G and x∗a=a∗x}  (1)prove that the order of H is greater than 1 (it implies that H≠{e})


My os version is 18.04  I'm trying to install os161 toolkit. I ran the following command  sudo add-apt-repository ppa:ops-class/os161-toolchain   I get the following error  E: The repository 'http://ppa.launchpad.net/ops-class/os161-toolchain/ubuntu bionic Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. sanat   This is my first time using linux and all this is gibberish to me


Copying and renaming excel files with Python

I am trying to copy an excel file and rename it. For example I have a file HI.xlsx and I want to copy it and rename it as BYE.xlsx. My code to do this is below and when I run it, the file BYE.xlsx is created, but it is corrupted.   Here is what I am using:  fIn = open(r"HI.xlsx") fOut = open(r"BYE.xlsx", "w")


How to label pie charts in ArcGIS for Desktop?

How can I add to pie charts in ArcGIS (10.1) labels of the values the charts are created with?


I have a problem with my Laptops DVD drive.  Early when I start my laptop with power button first screen is about starting BIOS and interrupting Startup the DVD drive rotates for once and computer gets started.   But now when I start my computer the DVD drive rotate  for two times for 1 sec because it is empty. When the computer gets started Windows welcome screen comes and DVD drive rotates again for a short time. When I click on start menu DVD drive again rotates. When ever screen lid is off I just put my fingers on touch pad DVD drive again rotates.   I don't know what is happening. This happens every time whenever I try to start Windows programs like NOTEPAD, WINDOWS MEDIA PLAYER, ETC.  Is there any way to stop this?


Can't see beyond a certain point in viewport?

For some reason I can't seem to see things in my viewport beyond a certain point, as if there is an invisible wall. For reference, the photo shows a cube, but I am unable to see the rest of it. If I drag my perspective around, the line at which the objects stop showing remains constant. Please help!


bash shell script: sed:how to replace path with variable at runtime

#!/bin/sh   JAVA_DIR=/opt/test echo "Editing $TEST_BIN/httpmon, setting correct java path to $PW_DIR/jre/bin/java" sed -i 's/"$install_dir\/jre\/jre"/"$JAVA_DIR"/g' httpmon1 > httpmon2 echo "done"  what is wrong in this shell script?


Coordinate Reference System in QGIS: Project vs Layer

I do not understand why there can be in QGIS different CRS for project and for layers. I have worked previously with subsurface petroleum software and there CRS "stuff" was lot more strict in that sense that data was almost always tied to the CRS of the project. Will the data be prone to inconsistency if there is different CRS for project and layers?


Sprouting Potatoes in Fridge? Safe to eat?

Have a bag of potatoes about maybe 3 weeks old. Still firmish, not green but with little small sprouts (maybe barely 1 cm) VERY small.  Are these ok to eat? I trimmed off the sprouts and the inside looked fine, and they are not green. Slightly softer but still firm.


Is it possible to dual boot two instances of Ubuntu 16.04?

I've been programming for about a year and I'm very new to Ubuntu. I'm currently working on a project with a mentor who suggested partitioning part of my drive with a fresh Ubuntu install. I've never done anything like this and most of the guides I've seen are for dual-booting Ubuntu and Windows/MacOS.  I'm currently running Ubuntu 16.04 on my laptop. I was wondering If I could keep my current setup and also partition part of my drive with a fresh install of Ubuntu 16.04?


Have installed Ubuntu and windows 7.But now while booting system boots via windows and no grub screen is seen.