In this story, three kids are going through a wild area, I believe mountainous, in order to find a thing/being that grants wishes.  There are two boys and a girl.  The older boy is depressed and upset, and doesn't say what his wish would be.  The girl says she wants to know what is going on at all times, what is really happening, or something like that.  The younger boy seems slightly immature or less intelligent and says he just wants to be happy.  They find the thing/being and everyone gets their wish.  Two kids walk home through the mountainous area.  The girl is really sad (she felt close to the older boy) but the younger boy doesn't understand why when it's such a beautiful day.  The end.  (The implication is that the older boy wished he was never born, and so he wasn't, but the girl knows "what's going on" so she remembers him, but the younger boy doesn't.)  For some reason my mind thinks this is David Brin.  I read it within the last ten years.  It might have been in a "best-of-the-year" type anthology, or another anthology.


Under what circumstances will a passive HDMI-to-VGA adapter work?

I have bought a no-brand, passive HDMI Male to VGA Female adapter, to link up a PC with a more dated monitor. It did not work.  After doing some reading, I have learned that buying such an adapter is often discouraged because in many cases it will not convert the signal from Digital to Analog, or the Motherboard/CPU on a specific computer might not be compatible with that particular adapter.   So my question is: seeing how there are so many of these passive adapters on the market, are there circumstances under which they actually do suffice to connect an HDMI output to a VGA input? Or are they generally just a rip-off?  Example of the kind of adapter I bought:


Why are certain flags not available from time to time?

From time to time, some flags are not available to me. I would, for example, like to flag  as off-topic, but the flag is not available for me. (It wasn't before the post was closed, as well.) The last time this happened, I flagged the post as "in need of moderator intervention" which was not correct, either. Why are certain flags sometimes not available? Is this some kind of bug, or is there a system that decides which flags I can use on which posts?


How do I find the PID of the current instance of the Bash shell i'm using?


I have one dictionary, like the following:  adict = {'1': alist, '0': blist, '2': clist}   I want to perform some things, for all lists in adict except the list with the key '0'.  So I have tried:  for key in adict:     if key is not '0':         do something   but the test doesnot work, something is done in all cases, including the one that key=='0'.  I cannot figure out, what is wrong, any help?


Horde on CentOS 5: Can't send outbound message?

My setup is local install so I don't expect it to receive emails from the internet. However I do expect it to be able send messages to the internet, but it doesn't seem like it. I have tried setting up on FreeBSD before and it was able to do so but I wasn't involved in the setting of the machine though. I was just tasked to setup Horde... Any insights please????


I know that $f(x,y)=\sqrt{|xy|}$ when $(x,y)\neq{(0,0)}$ is differentiable since partial derivatives exist and they're continous. When I do by definition $f_x (0,0)$ and $f_y (0,0)$, both are equal to $0$. Due to "Sufficient Condition for the Differentiability of Functions", can I conclude that it is differentiable?  My problem is that I think it isn't diff. because of an analogy to single-variable $f(x)=|x|$, but not sure. Thanks.


We all know what Cycles is, at least to a first approximation: Cycles is  a path tracing engine [...] Specifically, cycles is a "backwards" path tracer, which means that it traces light rays by sending them from the camera instead of sending them from light source(s)  —from   Understanding its implementation clearly requires some more technicalities, like the BVH, the specificity of volumetric shaders etc, but even without all those details it's pretty clear what's the "idea" behind it. In short (Cycles): rays are traced back from the camera until they reach a source of light or the sky. Every time they "hit" something they have different possible routes -- each with its own probability, as described by the material settings: they can reflect at specular angle (specularity), bounce at random angle (rough diffuse), transmit through the surface (refraction), etc -- and during this route they accrue color, intensity etc. Since there are probabilistic choices along the route, multiple rays with different random seeds are cast and then averaged (samples) (1). As for , we know what it's for: it is a «modern, high-quality viewport that will perform better than the current Blender viewport» (); we know what it is not for: it «uses approximations on the behavior of light and will not be as accurate» as Cycles (). But I think it hasn't been written yet "what it does". How would you shortly explain the workings of EEVEE to a friend (or to a class of non experts)? What are the main steps that go into the rendering process? Lit/shaded areas, occlusion, interaction with the materials, (possibly even subsurface scattering and volumetrics, that I guess must be somewhat tricky), etc... My description of Cycles above (1) is the type of understanding I'd like to get about Eevee. Thanks!


Is there a single word for the conjunction "and/or"?

For example:  "Would you like to eat a pizza and/or a hamburger"


Multiplicative group $(\mathbb R^*, ×)$ is group but $(\mathbb R, ×)$ is not group, why?

$\mathbb R^*$ refers to $\mathbb R$ without zero.  Please explain the statement "$\mathbb R$  is not a group under multiplication, it is a group under addition." in the . Basically:   Why is multiplicative group $(\mathbb R^*, ×)$ a group? Why is $(\mathbb R, ×)$ not group? Why are $(\mathbb R^*, +)$ and $(\mathbb R, +)$ groups?


From the pmset man page:     POWER SOURCE ARGUMENTS      -g with a 'batt' or 'ps' argument will show the state of all attached power sources.      […] Certain Apple battery calibration tools may temporarily disable   battery charging, even though your Apple portable is plugged into AC   power.      Such tools will never surprise you with this behavior; you will know   it's happening. This state will be reflected in an additional line of   output to 'batt' or 'ps' readings, including the pid of the app   inducing this behavior.       'ChargeInhibit':    1432    So, does any piece of publicly available software exist to force the battery not to charge?


Android calculator previous option function

I am trying to learn android development from the beginning here. So basically it will be a calculator. The way I code the calculate function is down below:   private boolean action = false;  private String fNum;  private String sNum;  private String preOp = "=";   Action as the flag to check if there is any previous option exist. fNum and sNum as the number needs to be taken care of. fNum is the one before calculate symbol button was clicked , sNum as the number after the symbol button was clicked. preOp as the storage for the last operation.  private double Calculate(String fn, String sn){     switch (preOp) {         case "plus":             return Double.parseDouble(fn) + Double.parseDouble(sn);         case "minus":             return Double.parseDouble(fn) - Double.parseDouble(sn);         case "multiply":             return Double.parseDouble(fn) * Double.parseDouble(sn);         case "device":             return Double.parseDouble(fn) / Double.parseDouble(sn);         case "=":             return Double.parseDouble(sn);         default:             return 0;     }  }   Function to actually run the calculate.  case R.id.buttonPlus:{             if(action){                 fNum = text.getText().toString();                 text.setText("0");                 preOp = "plus";                 action = true;             }             else if (!action){                 sNum = text.getText().toString();                 text.setText(String.valueOf(Calculate(fNum, sNum)));                 preOp = "plus";             }         }break;         case R.id.buttonE:{             if(action){                 sNum = text.getText().toString();                 text.setText(String.valueOf(Calculate(fNum, sNum)));                 preOp = "=";             }         }break;   The button functions.  So I have got the error when I clicked the + button:  12-04 05:53:04.198 31194-31194/tian.secondproject E/AndroidRuntime: FATAL EXCEPTION: main     Process: tian.secondproject, PID: 31194     java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.lang.String.trim()' on a null object reference     at java.lang.StringToReal.parseDouble(StringToReal.java:263)     at java.lang.Double.parseDouble(Double.java:301)     at tian.secondproject.MainActivity.Calculate(MainActivity.java:21)     at tian.secondproject.MainActivity.onClick(MainActivity.java:226)     at android.view.View.performClick(View.java:5198)     at android.view.View$PerformClick.run(View.java:21147)     at android.os.Handler.handleCallback(Handler.java:739)     at android.os.Handler.dispatchMessage(Handler.java:95)     at android.os.Looper.loop(Looper.java:148)     at android.app.ActivityThread.main(ActivityThread.java:5417)     at java.lang.reflect.Method.invoke(Native Method)     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)   So, am I doing it with a wrong method? or there is just some simple mistake I have made?  Thank you :)


$x,y,z$ are positive reals. for a triangle of side lengths $ a, b, c$ , and area $A$, the following inequality holds: $$(xa^2+yb^2+zc^2)^2\ge 16(xy+yz+zx)A^2$$ This is like a weighted Weitzenböck's inequality. I hope to get some tips to prove this question


If you leave a ball weighing 10 kg at a height of 500 km above sea level (neglecting air friction).  How can calculate how long the ball hits the ground and what will be its speed?   I know that: On earth I can calculate the time taken to the object to fall by this equivalent:  x = x0 + v0t + (at^2)/2 x = 0 x0 = 500000 v0 = 0 a = -g = 10 m/s^2 0 = 500000 - 5t^2 t = 316.227sec   Also I know how to calculate the force between objects:  g = GMm/r^2


What counts as ground for Tenser's Floating Disk?

What counts as ground for this ritual, if you have a 5x5 piece of stone/paper/metal/wood under the disk, and that is moved up, say 10 feet, would the disk phase through that stone, or hover 1 foot above it? What about floating over water?


As you can see in the picture the black things shows thru the glass but the other glass shape doesnt. The other glass shape is the same distance from the glass so its not just out of range.  The other black things only show through the glass when their materials have "screen space refraction" de-selected  The glass must have "screen space refraction" selected to show objets behind it.   Other objects in same the glass material won't show through this glass.  What could be wrong here? Why are the black things visible but not the other glass shape?  Thanks to anyone who knows anything about this!


How to get unique values and cell counts of a raster in QGIS 2.6?

I have a soil layer that I have clipped to a polygon area and I want to obtain the unique cell values (eg. each soil type) and the cell count for each value.   I have a lot of experience with ArcMap (where this is a simple procedure) however I want to learn to use QGIS. I have looked online and can't find an answer. Is there an easy way of doing this?


Purchased Domain with a Company that No Longer Exists

I purchased a domain through a company that has ceased function, but I need access to be able to move the domain and utilize my property.  Thoughts?


I read recently that the galactic "flatness" of the Milky Way is due to the rotation of the galaxy combined with a vast stretch of time.  Yet, I also read where 1) the Milky Way rotates once every 225 million years, and 2) the Milky Way is about 12 billion years old.  This means -- all other things (such as galactic collisions adding substantial amounts of mass) being equal -- that the Milky Way has only rotated approximately 53 times in its existence.  How is that enough time to flatten the disk?


Is the set $S=\left\{\left(z_1,z_2\right)\in \mathbb C\times \mathbb C:z_1^2+z_2^2=1\right\}.$ compact?

Consider the set $$S=\left\{\left(z_1,z_2\right)\in \mathbb C\times \mathbb C:z_1^2+z_2^2=1\right\}.$$  Is this set compact in $\mathbb C^2$ ?  As $\mathbb C^2$ is a finite dimensional space so a subset of it is compact if and only if it is closed and bounded.  But $z_1^2+z_2^2=1$ gives $(x_1^2+x_2^2)-(y_1^2+y_2^2)=1$ and $x_1y_1+x_2y_2=0$ , where $z_1=x_1+iy_1$ and $z_2=x_2+iy_2$.  But from here how I can show that the set is closed and bounded ?


Real-time symmetrical modeling with distinct objects in Blender

I would like to create a 3D model that has a wide variety of individually selectable objects on the right side of the x-axis, and then all of those same objects mirrored dynamically across to the other side of the x-axis. How do I do it?  What I want to achieve   Create an object with an origin at 0,0,0 and no parts jutting into the left side of the x-axis. Create another object (say, a cube) somewhere on the right side of the x-axis. Somehow create an association between these two objects that lets me still select them easily later. Apply a mirror modifier to the association. Create more objects on the right side of the x-axis and add them to the association so that they are also mirrored on the other side of the x-axis. Add objects, move objects, change objects, and have them update in real time across the axis.   What I've tried  - Grouping objects and then putting a modifier on the group (I wasn't able to get this to work)  - Ctrl+J to join the meshes (but then I can't select them easily individually)


Suppose that every subsequence of $X=\{x_n\}$ has a subsequence that converges to $0$. Show that $\lim X= 0$.   I want to solve this question with the following hints:     Prove $\varlimsup x_n$, $\varliminf x_n$ are both finite. Assume $\varlimsup x_n=l$ and $\varliminf x_n=m$. Show that $l=m=0$   I have seen it here   But I want to solve as per the hint given above. Please help me. A complete solution will help me a lot.


I am using this code to disable cache in php but this code is not working on any browser. Please somebody help me, I don't want to save php web page in cache memory  header('cache-control: no-cache,no-store,must-revalidate');  header('pragma: no-cache');  header('expires: 0');


How to convert String (input text) to md5 in spring-hibernate

How to convert String from input text to md5? I have no clue.  This is part of my .jsp
 <spring:message code="password" text="default text" />	 :	 <input type="password" name="password" required>	     and this is my controller  @RequestMapping(value="/admin/addUser.html", method=RequestMethod.POST) public ModelAndView createUserAdmin(@ModelAttribute UserAdmin useradmin, ModelMap model)throws Exception {     userService.save(useradmin);     model.addAttribute("successAdd", "true");     return listUserAdmin(model); }   Thanks for any help :)


present perfect how to construct interrogative sentences?

For me the following two are identical. Are there difference or they can be used interchangeably?     How long you have been teaching English?      How long have you been teaching English?


Can I ONLY use the calligraphy part of a font?

I'm using \usepackage[utopia]{math-design}and really enjoy the calligraphy font. However, I don't like the rest of the maths font. Therefore I want to hear whether it is possible to only use the calligraphy part of utopia and to use the standard LaTeX maths font for everything else


How i can convert User to FieldUserValue inside my CSOM code

I have the following CSOM code:  Group group = web.SiteGroups.GetByName(subsitename);                      List<FieldUserValue> currentgroupUsers = new List<FieldUserValue>(); foreach (User user2 in group.Users) {      currentgroupUsers.Add(***********); }   So how I can convert/cast a User object to FieldUserValue object?


The problem appeard after i turned off ubuntu from the power off button of the computer ,I think there were some things going on . Now when i turn on my computer it starts but short after that i see a black screen with a white underscore blinking. I inserted a bootable usb with ubuntu , ended up partitioning de hard drives, installing the system and when i press ok on the message to restart the system so that the instalation be completed i  end up at the ssame white underscore blinking , doesn't goes any further .. When i try to enter bios by typing tab it seems like it's preparing some output is printed on the screen but it's stops and return to the black screen .I can acces my system if i enter the boot priory section and choose the drive that is ubuntu installed on .. I've tried to install it on another partition and i get this:Sorry an error occured and it was not possible to install the bootloader at the spcified location how would you like to proceed choose a different device to install the bootloader on , continue without bootloader ,exit


Find and Replace Inside a Text File from a Bash Command

What's the simplest way to do a find and replace for a given input string, say abc, and replace with another string, say XYZ in file /tmp/file.txt?  I am writting an app and using IronPython to execute commands through SSH — but I don't know Unix that well and don't know what to look for.  I have heard that Bash, apart from being a command line interface, can be a very powerful scripting language. So, if this is true, I assume you can perform actions like these.  Can I do it with bash, and what's the simplest (one line) script to achieve my goal?


How to create multidimensional array with my objects in Java?

Could You tell me whether i can create multidimensional array  which is created with my objects in java?  In other words:  I have got this class:  public class ClosestObject { public Double distance; public String classes;  public ClosestObject() {         this.distance=new Double(0);         this.classes=new String("");         // TODO Auto-generated constructor stub     }    }   And I want to create multidimensional array in another class in that way:      ClosestObject[][] closestobj=new ClosestObject[query.length][learning_set.length];      for(int i=0; i<query.length;i++)     {         for(int j=0;j<learning_set.length;j++)         {             closestobj[i][j].distance=Math.abs(query[i]-learning_set[j][0]);             closestobj[i][j].classes=classes[j][0];         }     }      for(int i=0;i<closestobj.length;i++)     {         for(int j=0;j<closestobj[i].length;j++)         {             System.out.println(closestobj[i][j].distance + " " + closestobj[i][j].classes);         }     }   Unfortunatelly I get this error:  Exception in thread "main" java.lang.NullPointerException at KNN.Find_closest_distance(KNN.java:60) at KNN.main(KNN.java:37)   Could someone tell me where i made mistake. Thank You in advance :)


I'm new on Lubuntu and so I downloaded a editor like LightTable and it runs only with this command from command line     ./LightTable   So HOW CAN I ADD THIS SOFTWARE ON MY MENU ?


Creating WiFi Access point on a single interface in Linux

I am trying to create a WiFi hotspot or an access point on my Linux laptop. I am using Opensuse Kde 12.3.  I found out a software called hostapd which lets you create hotspot but it requires two interfaces. One connected to the internet and the other on which you want to create the access point () . The problem I have is that I don't have Ethernet connection. The wlan interface is being used to connect to the internet.   Is there any way to create the hotspot on the same interface that is connected to the Internet (like the software connectify does on Windows)? I was thinking of creating a virtual interface (like the one airmon-ng creates to monitor wifi) and use it as the second interface. Is this possible?  UPDATE  Here's what i have been able to do up till now :  1) Create 2 interfaces ( one as station and the other as an access point )    iw phy phy0 interface add mySta type station   iw phy phy0 interface add myAcc type __ap   2) Give them seperate Mac ID   ifconfig myAcc hw ether A4:17:FE:6E:00:53 ifconfig myAcc 192.168.27.1 up   3) start hostapd on the myAcc interface  4) start dnsmasq to provide ip address to the connecting devices  All of this works. Devices are able to connect to this network and obtain Ip Address.  The next step is to provide ip masquerading   iptables --table nat --append POSTROUTING --out-interface mySta -j MASQUERADE iptables --append FORWARD --in-interface myAcc -j ACCEPT   But the mySta interface now fails to connect to the internet. It is able to obtain the Essid but it cannot obtain the ip address.  The command dhclient mySta doesn't show any message and after some time gives the error :  ls: cannot access /var/run/netconfig//mySta/: No such file or directory   Can someone figure out how to obtain the ip address ?


Is there any app available in the Android Market for Stack Exchange sites?


Prove that $\sum_{k=1}^\infty \frac{e^kk!}{k^k}$ does not converge.

I am doing an exercise where I have to consider the radius and interval of convergence of a series of functions. I found one endpoint to be $e/2$ and I now need to consider whether or not the following sum diverges. $$\sum_{k=1}^\infty \frac{e^kk!}{k^k}$$    I have found from calculators that it diverges but I do not know how to prove this.  Cauchy's ratiotest is inconclusive, as it gives the value 1.  Any help?


I'm currently doing an introductory course to quantum mechanics, and came across an assumption that Planck used in solving the UV catastrophe. From what I understand, he essentially stated that that the change in energy cannot be smaller than $hf$. So generally $\Delta{E}$ = $n*hf$ where $n$ is a real number. This makes sense, but I never understood how energy is truly then quantised, as can't light take an infinite number of possible frequencies? (not at the same time but just generally). Maybe I'm just misunderstanding the statement or making it overcomplicated - in any case please do shed some light.


I was wondering how gravity would behave on object of different shapes.   If the Earth was squeezed into a thin disk what would the gravitional acceleration be at the center of the flat surface? Would it be really low because the amount of matter beneath me would be small? If I stood on the edge would the gravitational acceleration be enormous because the amount of matter beneath me was huge? If an object is lowered into the Mariana trench will the effect of gravity increase because it gets closer to the center of the Earth?


Why does editing posts on SO require a minimum of 6 charaters?

I have just recently started editing the post on Stack Overflow.  I found some posts which only required 2-3 character changes like they had correct grammar but some mistakes in spelling.  When I tried to correct the spelling mistakes, and clicked on "edit", it said:  Edits must be at least 6 characters   I don't know why Stack Overflow added this limit. How can I edit only 3-4 characters in a post?


How can i upgrade my existing ubuntu 12.04 to 13.04 using terminal... please help me with the procedure. I am having problem regarding upgrade.


The texts speak of the collection of all groups as a "class". Can someone clarify what it means to be a class, how it is different from a set and why we cannot look at the set of all groups, and instead must deal with classes.


Sound disappeared in Ubuntu 19.10, previous solutions not working

I tried to play sound today, and no sound.  Similar questions and my failed attempts:    but no solution here pulseaudio -k && sudo alsa force-reload changed nothing pacmd list-cards lists 0 cards.   also, typing pacmd set-card-profile 0 output:analog-stereo gives No card found by this name or index.  source:    Trying sudo alsactl init 0   gives  alsactl: init:1778: Cannot find soundcard '0'...  source:    mv ~/.config/pulse ~/.config/old_pulse and then rebooting also fails source:  sudo apt-get remove alsa-base pulseaudio sudo apt-get install alsa-base pulseaudio   failed.  Source:   6.  sudo apt-get --purge remove linux-sound-base alsa-base alsa-utils  sudo apt-get install linux-sound-base alsa-base alsa-utils  sudo apt-get install dkms build-essential linux-headers-`uname -r`  alsa-base alsa-firmware-loaders alsa-oss alsa-source alsa-tools  alsa-tools-gui alsa-utils alsamixergui  sudo usermod -a -G audio username  sudo reboot   failed, source:


How to make a file writeable for its owner?

Linux newbie here, working on Debian Jessie.   Why does chmod u+w not make a file writeable for its owner?  I have run:  sudo chmod u+w /var/log/myapp/gunicorn-error.log   But now if I list the permissions on the file, it still doesn’t seem to be writeable:  ls -al /var/log/myapp/ total 52 drwxr-xr-x  2 opuser webapps  4096 Sep  1 11:08 . drwxr-xr-x 10 root   root     4096 Sep  1 11:24 .. -rw-r--r--  1 opuser webapps     0 Aug 23 07:11 gunicorn-access.log -rw-r--r--  1 opuser webapps 38639 Sep  1 11:15 gunicorn-error.log   What am I doing wrong?


Why can light (photons) bends in a curve through space without mass?

I've heard that light can form a curve if they travel near high-mass stars or even a black hole with strong gravity. Which is according to this   $$\large F_{g}=\dfrac{Gm_1m_2}{r^2}.$$  But I've also heard that photons do not have (rest) mass! So it doesn't fit that equation anymore! But why can photons be pulled by gravities without (rest) mass? Could someone explain that?


$a_n$ converges to $a$, but why $\frac{1}{n+1}(a_0+a_1+\cdots+a_n)$ also?

i have asked this question today already, but i couldnot find the answer to my second question (which is this)which came after the answer to the first question. First of all, sorry duplicate question, and please dont redirect me to another question.   i cannot follow the thought that the sequence $\frac{1}{n+1}(a_0+a_1+\cdots+a_n)$ converges to $a$. my idea is this:   $$\frac{1}{n+1}(a_0+a_1+\cdots+a_n)=\frac{a_0}{n+1}+\frac{a_1}{n+1}+\cdots+\frac{a_n}{n+1}$$ and each term goes to $0$ as $n$ grows, but how can the sum of $0+0+0+0+0$ can converge to $a$ ?


apt-get cannot connect to Ubuntu archives

I just installed a fresh version of Ubuntu 19.10 today, and the first thing I decided to do was to install GNU Screen, using sudo apt-get install screen. my output was: Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package screen  I figured the package archives were not quite updated as it was a clean install so I tried sudo apt-get update. This is what I got: Get:1 http://security.ubuntu.com/ubuntu eoan-security InRelease [97.5 kB]       Err:2 http://au.archive.ubuntu.com/ubuntu eoan InRelease   Cannot initiate the connection to au.archive.ubuntu.com:80 (2001:388:30bc:cafe::beef). - connect (101: Network is unreachable) Could not connect to au.archive.ubuntu.com:80 (202.158.214.106), connection timed out Err:3 http://au.archive.ubuntu.com/ubuntu eoan-updates InRelease      Cannot initiate the connection to au.archive.ubuntu.com:80 (2001:388:30bc:cafe::beef). - connect (101: Network is unreachable) Err:4 http://au.archive.ubuntu.com/ubuntu eoan-backports InRelease   Cannot initiate the connection to au.archive.ubuntu.com:80 (2001:388:30bc:cafe::beef). - connect (101: Network is unreachable) Fetched 97.5 kB in 31s (3,106 B/s) Reading package lists... Done Building dependency tree        Reading state information... Done All packages are up to date. W: Failed to fetch http://au.archive.ubuntu.com/ubuntu/dists/eoan/InRelease  Cannot initiate the connection to au.archive.ubuntu.com:80 (2001:388:30bc:cafe::beef). - connect (101: Network is unreachable) Could not connect to au.archive.ubuntu.com:80 (202.158.214.106), connection timed out W: Failed to fetch http://au.archive.ubuntu.com/ubuntu/dists/eoan-updates/InRelease  Cannot initiate the connection to au.archive.ubuntu.com:80 (2001:388:30bc:cafe::beef). - connect (101: Network is unreachable) W: Failed to fetch http://au.archive.ubuntu.com/ubuntu/dists/eoan-backports/InRelease  Cannot initiate the connection to au.archive.ubuntu.com:80 (2001:388:30bc:cafe::beef). - connect (101: Network is unreachable) W: Some index files failed to download. They have been ignored, or old ones used instead.  I'm really not sure why it would be doing this, other than maybe some first-use hiccups? The computer is definitely connected to the internet, as I am writing this from that machine, and I have tried running the commands after rebooting and it still gives the errors. I can't seem to be able to connect to au.archive.ubuntu.com at all. ping au.archive.ubuntu.com just sits there without a response. If anyone could help, that would be great! If any extra information is required I'd be happy to edit it into the question.


Simulation of logistic regression power analysis - designed experiments

This question is in response to an answer given by @Greg Snow in regards to a  I asked concerning power analysis with logistic regression and SAS Proc GLMPOWER.  If I am designing an experiment and will analze the results in a factorial logistic regression, how can I use  ( and  ) to conduct a power analysis?  Here is a simple example where there are two variables, the first takes on three possible values {0.03, 0.06, 0.09} and the second is a dummy indicator {0,1}. For each we estimate the response rate for each combination (# of responders / number of people marketed to). Further, we wish to have 3 times as many of the first combination of factors as the others (which can be considered equal) because this first combination is our tried and true version. This is a setup like given in the SAS course mentioned in the linked question.    The model that will be used to analyze the results will be a logistic regression, with main effects and interaction (response is 0 or 1).   mod <- glm(response ~ Var1 + Var2 + I(Var1*Var2))   How can I simulate a data set to use with this model to conduct a power analysis?  When I run this through SAS Proc GLMPOWER (using STDDEV =0.05486016  which corresponds to sqrt(p(1-p)) where p is the weighted average of the shown response rates):    data exemplar;   input Var1 $ Var2 $ response weight;   datalines;     3 0 0.0025  3     3 1 0.00395 1     6 0 0.003   1     6 1 0.0042  1     9 0 0.0035  1     9 1 0.002   1; run;  proc glmpower data=exemplar;   weight weight;   class Var1 Var2;   model response = Var1 | Var2;   power     power=0.8     ntotal=.     stddev=0.05486016; run;   Note: GLMPOWER only will use class (nominal) variables so 3, 6, 9 above are treated as characters and could have been low, mid and high or any other three strings. When the real analysis is conducted, Var1 will be used a numeric (and we will include a polynomial term Var1*Var1) to account for any curvature.  The output from SAS is     So we see that we need 762,112 as our sample size (Var2 main effect is the hardest to estimate) with power equal to 0.80 and alpha equal to 0.05. We would allocate these so that 3 times as many were the baseline combination (i.e. 0.375 * 762112) and the remainder just fall equally into the other 5 combinations.


There is a question on the complex analysis of Conway "Functions of one complex variable" (pg.57 #28) about the mapping properties of $(1-z)^i$. Can anyone describe me what does the exponent '$i$' mean? What does it do to $(1-z)$? I am confused. Can i write in the following way?  $(1-z)^i=e^{i \log (1-z)}=\cos (\log (1-z))+i \sin (\log (1-z))$


How to create customized "google search bar" gifs

I am using Firefox on Ubuntu 16.04.  What is the best way to create customized "google search bar" gifs like ?  Is there a software for doing this? A website? Or should I just record my screen activity? (if latter, any tips/software suggestions are welcome).


Non-vanishing of Dirichlet $L$ function $L(s,\chi)$ for $Re s=1$

Assuming $\zeta (1+it)\ne 0 , \forall t\in \mathbb R$ , is there an easy proof that $L(1+it , \chi ) \ne 0 , \forall t\in \mathbb R$ where $\chi$ is any non principal Dirichlet character ?


let $x_1, x_2, ... , x_{2014} $ be the roots for $x^{2014} + x^{2013} + ... +x +1 = 0 $ find $\sum_{k=1}^{2014} 1/(1-x_k) $.  So What I tried to do is to consider x^3 function and get the elementary symmetric functions. the find the sum of  $\sum_{k=1}^{3} 1/(1-x_k) $. I lost and did not work.  How I can approach this problem?


Why is "insufficient storage" wrongly reported when installing an .apk via adb?

I have an HTC Desire running Froyo. It is not rooted, nor have I installed any custom ROM.  I get an "Insufficient Storage" error when I'm trying to install an app via adb/eclipse. The .apk is only 300KB, and the phone reports 14MB free of internal storage, and 2.2GB free on the SD card. (I have just uninstalled a few large apps to make sure there's plenty of room.)  It is obviously completely wrong. There's easily plenty of room in the 14MB of internal storage for my 300KB app.  What can I do to fix it?


Some minutes ago my computer crashed because apparently my hard drive was full. After booting in recovery mode I then found out that my syslog file in /var/log was 64GB large. I saved the end of the file on another partition and then deleted it. Apparently docker seems to have been the problem because I found a lot of this at the end of the file and there was a docker process running at 200% CPU the whole time. After clearing the log and killing docker everything seems to be normal.  Nov 15 01:44:08 Elemental docker.dockerd[1120]:  time="2019-11-15T01:44:08.727060251Z" level=error  msg="failed to get event" error="rpc error: code =  Unavailable desc = all SubConns are in TransientFailure, latest connection  error: connection error: desc = \"transport: Error  while dialing dial unix /run/containerd/containerd.sock:  connect: permission denied\"" module=libcontainerd namespace=plugins.moby Nov 15 01:44:08 Elemental docker.dockerd[1120]:     time="2019-11-15T01:44:08.727116701Z"  ...   And so on. I hope this problem won't appear again but still I would like to know what might have happened here.


Find the sum  $$\sum_{n=0}^\infty \dfrac1{n!}$$   Sorry, I couldn't find the symbol for Sigma.      Sigma(1/n!) I tried this but couldn't do it.  Any suggestions for the problem are welcome.


$|A \cup B| = \mathfrak{c}$, then $A$ or $B$ has cardinality $\mathfrak{c}$.

$A$ and $B$ are sets. $|A \cup B| = \mathfrak{c}$, prove that $A$ or $B$ has cardinality $\mathfrak{c}$.  This is an exercise problem from my textbook. It's easy if I assume CH to be true. But how can I prove this without it? I don't know how to eliminate the case of $A$ and $B$ both has cardinality larger than that of natural numbers and strictly smaller than that of reals.


What is the correct way to create a object array in java?

I've seen examples such as:  Type arrayname[] = new Type[];   also as written as:  Type[] arrayname = new Type[]   I am quite confused about such expressions!  Where exactly should I put the []?


Access denied for user 'debian-sys-maint' - installing mysql?

Im trying to install mysql and I get the error: mysql_upgrade: Got error: 1045: Access denied for user 'debian-sys-maint'@'localhost' (using password: YES) while connecting to the MySQL server  After some searching, I find this is perhaps giving access to debian-sys-maint, so I did this: sudo cat /etc/mysql/debian.cnf  Then set the debian password in mysql: mysql -u root -p <password> GRANT ALL PRIVILEGES ON *.* TO 'debian-sys-maint'@'localhost' IDENTIFIED BY 'password-here';  Then I restart: sudo /etc/init.d/mysql restart  And try and configure again: sudo dpkg --configure -a  I get the same error.


Are There Infinitely Many Square Triangular Numbers?

Toying around with triangular numbers, it seems that there are already 4 squares below 1000. At least I get this one:  ?- between(1,1000,N), T is N*(N+1)//2, sqrtrem(T,_,0). N = 1, T = 1 ; N = 8, T = 36 ; N = 49, T = 1225 ; N = 288, T = 41616 ; No   Are there infinitely many square triangular numbers?


Any line intersect with $bd(S)$ at at most two points. Then $S$ or $S^c$ must be convex.

Let $S$ be an open set on $\mathbb R^2$. $bd(S)$ is its boundary. We've known that any line intersect with $bd(S)$ at at most two points. Is it possible to show that one of the following conditions must hold? (1) $S$ is connected convex or $S^c$ is connected convex (2) $bd(S)$ is a discrete set  I first try to show that $S$ is connected by contradiction. Suppose $S$ is not connected. That is, there exists open sets $A,B\subset S$ such that $A\cap B=\emptyset$. Then, there must exists a line crossing both $A,B$, and the line does not tangent their boundary (how to prove the existence of this line???) This contradicts to the assumption that any line only intersect with $bd(S)$ twice. Similarly, we can show that $S^c$ must either have empty interior, or $S^c$ is connected. Therefore $bd(S)$ must be also connected. Then suppose that $S$ is not convex. By definition, there exists two points, $x,y\in bd(S)$, such that, for some $a\in (0,1)$, $z=ax+(1-a)y$ does not belong to $S$. If the previous statement holds, then we have for any $a\in (0,1)$, $z=ax+(1-a)y$ does not belong to $S$. This implies that $S^c$ is connected and convex?


Infinitely many primes of the form $\lfloor \sqrt {3} \cdot n \rfloor $?

How to prove or disprove following statement :     There are infinitely many primes of the form : $\lfloor \sqrt {3} \cdot n \rfloor $    Note: This is a problem I made myself.  There is a theorem that states :  $\lfloor nx \rfloor = \begin{cases}  n\lfloor x \rfloor, & \text{if } 0 \leq \{x\} < \frac{1}{n} \\  n\lfloor x \rfloor +1, & \text{if } \frac{1}{n} \leq \{x\} < \frac{2}{n} \\  n\lfloor x \rfloor +2, & \text{if } \frac{2}{n} \leq \{x\} < \frac{3}{n} \\  \vdots \\  n\lfloor x \rfloor +n-1, & \text{if } \frac{n-1}{n} \leq \{x\} < 1 \\ \end{cases}$  where $\{x\}$ is a non-integer part of $x$ .  Hence :  $\lfloor \sqrt{3}\cdot n \rfloor = \begin{cases}  n, & \text{if } 0 \leq \sqrt{3}-1 < \frac{1}{n} \\  n +1, & \text{if } \frac{1}{n} \leq \sqrt{3}-1 < \frac{2}{n} \\  n +2, & \text{if } \frac{2}{n} \leq \sqrt{3}-1 < \frac{3}{n} \\  \vdots \\  2n-1, & \text{if } \frac{n-1}{n} \leq \sqrt{3}-1 < 1 \\ \end{cases}$  How can I proceed from here ?


Error message "option_id" when flagging a question on the iOS App

I wanted to report  on Apple Stack Exchange as off topic, but when I tapped "flag" I get this error message:     I am using iOS 8.1.1 and the latest version of the Stack Exchange App (1.2.1)


gnome-shell's meson dependencies on Ubuntu 20.04

Preamble: I have decided that I would like to build gnome-shell from source (after ). My system is a stock Ubuntu 20.04.2 with Xorg Server, GDM3, Gnome desktop, and Mutter. I have cloned the gnome-shell  (recursively) with git, and have checked out the gnome-3-36 branch. On the only git submodule, subprojects/gvc, I have checked out the master branch, because studying git branch --all, that seemed to be the only one to make sense. Then I installed meson (v 0.53.2), and tried running meson builddir in the gnome-shell working tree root, as I have seen from . Challenge: Through error messages I have learned about missing dependencies. Then I have installed gcc, and after another failed attempt, cmake. After this, I still got errors about missing dependencies, which I started to search for and install with Synaptic one by one, after each error message of a new failed build attempt. In this fashion, I have so far installed such packages as libecal2.0-dev, libgcr-3-dev, libgirepository1.0-dev, and libgjs-dev. Now I feel stupid, and I think meson could install all these for me in a single process, with some command: like npm does with npm install.  looks somewhat like the npm ecosystem's package.json, so I guess I should be able to have dependencies installed by meson... Is that right? Now, to remain with the npm comparison, it strikes me that when I run npm install, I get a self-contained directory, node_modules/, where the (project's) dependencies are added. In contrast, I so far have installed my meson dependencies globally on my system. Does that make sense? Should I do it differently? Is there a better way?  Update 1:  this command: sudo apt install build-essential I thought it might be a useful shortcut, but for me it returns: "build-essential is already the newest version". Seems like the gnome-shell project's dependencies are beyond of what's considered essential.  Update 2: I have continued with manually installing dependencies as they came up, while keeping notes of what these were: libecal2.0-dev libgcr-3-dev libgirepository1.0-dev libgjs-dev libmutter-6-dev libpolkit-agent-1-dev libstartup-notification0-dev libgnome-desktop-3-dev libgnome-bluetooth-dev libnm-dev xsltproc sassc libpulse-dev asciidoc-base  After installing these with Synaptic, the meson build command proceeded until a successful exit. Just for a note, this stuff was huge (the dependencies of dependencies), I have the impression that gigabytes of disk space was used for them.  At this point @muru suggested : # So I ran sudo apt-get build-dep gnome-shell --dry-run  # then sudo apt-get build-dep gnome-shell  For this to work however, I had to check a checkbox and select a server for "Source code" in the  — again, thanks to @muru's guidance. Anyways, sudo apt-get build-dep gnome-shell has installed 36 more packages on top of what already had been installed. At this point however I feel optimistic that I am well equipped for the actual compilation, not just for the mere meson build.  Update 3: Considering how helpful this thread may be for any newcomer willing to work with meson in general or on the gnome-shell specifically, I would like to save this question from being deleted. I would like to move the info in the "Update 2" section into an answer. That would enable us to keep this collection of valuable information together in one place. So I cast a reopen vote.


Given $\limsup \frac{a_n}{b_n} < \infty$. Prove there is a constant M such that $a_n \leq Mb_n$

Given sequences $\{a_n\}$ , $\{b_n\}$ of positive real numbers and $\textrm{ limsup } \frac{a_n}{b_n} < \infty$. Prove there is a constant M such that $a_n \leq Mb_n$          Defn: Let $(a_{n})_{n=1}^{\infty}$ be a bounded sequence. Define the sequence $c_n = \sup \{a_{k}: k \geq n\}$ for $n \geq 1$. If the sequence $c_n$ converges, then the value it converges to is the limit superior of $(a_n)$.      Attempt:  So given that the lim sup is finite, it means there exists a value M such that for all $n > k$, $$\frac{a_n}{b_n} < M \\ \Rightarrow \ a_n \leq Mb_n$$   Comment: Surely there is more to it than this and I have missed something.....


Change id with jquery: Why doesn't it work?

I use this code to change id to an <input type="button" id="avvia_timer" value="AVVIA" />:  $("#avvia_timer").click(function() {     $(this).val("INIZIA");     $(this).attr("id", "inizia_timer"); });   I changed id with $(this).attr("id", "inizia_timer"); Then I want to show 'id' with an alert but doing click on the element with the new id  $("#inizia_timer").click(function() {     alert($(this).attr("id")); });   this doesn't work. Why? How can I fix?  Html code:
     <input type="button" id="avvia_timer" value="AVVIA" />     <input type="button" id="stop_timer" value="FERMA" />     Timer


I am creating a table which has create_date and modify_date field in mysql, but I am struggling in decide which data type is the best choice for these 2 fields. Should i use date time for both fields, or should i use date time for create_date and time stamp for modify_date ?


What is the maximum printing size for 12 Megapixels camera

The recommendation for printing images seems to be they should be printed at 300 dpi, so if I have a 12 Megapixel images in 4:3 format that would limit me to 12.5" x 10".  My question is if I have a really good lens and the image is totally in focus even when zoomed in to its pixels limit does that allow me to print at larger size or is the 12.5" x 10" limit the max size if image totally in focus.


Here we go again, the old argument still arises...   Would we better have a business key as a primary key, or would we rather have a surrogate id (i.e. an SQL Server identity) with a unique constraint on the business key field?   Please, provide examples or proof to support your theory.


Yet another question about passing parameters when compiling. I thought I had a good (for me) solution, by compiling with different jobnames and do conditional compilation on the basis of the jobname, using etoolbox and \ifdefstring; but it does not work. What's wrong with the following code? It seems that the \ifdefstring always evaluate to false.  % % Save this file as A.tex % compile it with 'latex A.tex' % compile it again with 'latex -jobname B A.tex' % you end up with A.dvi and B.dvi. % \documentclass{article} \usepackage{etoolbox}  \begin{document} The current jobname is: \jobname  \ifdefstring{\jobname}{A}{This file should be named A.dvi}% {This file should be named B.dvi}  \end{document}   EDIT: Actually I did not understand the proposed answer (and I tried it unsuccesfully): I should say I am not a TeXpert, only a LaTeX user. I would like to get an answer in terms of the usage of the package etoolbox, which, as far as I understand, is the implementation bit of such affairs whithin LaTeX3. I wrote the above bit of code using the instructions of etoolbox, which says that \ifdefstring{<command>}{<string>}{<true>}{<false>} executes true or false according to wether the command matches the string. I guessed that the problem was that \jobname is not a command in the sense of LaTeX, and I tried to define \newcommand{\Jobname}{\jobname} to "commandify" it, but it did not work. I think that, since LaTeX users which are not TeXperts browse this forum, it would be nice to have a full LaTeX solution if possible. Thank you all (and sorry for making this required edit so late, I was offline for a couple of days).


Why do I need multiple sites for the same property in Google Webmaster Tools?

In researching the best practice for adding sites to the Search Console, I've often seen it suggested to add separate properties for different versions of the same website. Even in  it states:     "Similarly, if your site has http:// and https:// versions, you should   add each as a separate site."   I've seen the same suggested for www/non-www. So if a site is accessible at all the variations of http/s and www/non-www we should have four properties.  But what if the site is only accessible at one variant? i.e. https and www are forced via htaccess, so only  can ever be accessed - should we still add all the variants?   In essence, the problem is that I don't know why Google wants us to do this, so I can't work out if it'll be ok just to have one instance.


I am trying to troubleshoot the performance issue on one of the SP which executes throughout the day daily every 20 mins and on avg completes under a min.  For past couple of weeks it happens once in a week that it will stuck and keep running for hours. Stats maintenance is done daily for modified stats and automatic update stats on is ON  There is no change to SP neither too much of load being increased in that run time.  I recompiled that SP to see if the plan was bad due to parameter sniffing issue, but does not help.  Due to security constraints i am not able to share the plan or any table structure here.  I know without seeing plan and query its tough to comment, but need possible ideas on what else should i be checking here?


Unexpected output voltage in opamp (LM741, DC, single supply) circuit

As a beginner I tried to make a simple DC circuit with an opamp on a single supply. This is what I came up with:         – Schematic created using   I use R3 and R4 as a voltage divider to get 1V between the inputs of the opamp, and R1 and R2 in the noninverting configuration. I tested this circuit in a few simulators and they show 3V at the output.  $$ Gain = 1 + \frac{R2}{R1}=1+\frac{560}{270}\approx3 $$    I built the circuit and measure 5.64V where I expected 3V. What am i doing wrong?


How to check if there is a congestion in my network?

How can I check if there is congestion between my wireless router and my cable modem?


$ |G_1 |$ and $|G_2 | $ are coprime. Show that $K = H_1 \times H_2$

Let $G_1$ and $G_2$ be finite groups and let $K \le G_1 \times G_2$      (i) Set $H_1 = \{ g \in G_1 : (g,e) \in K \}$ and $H_2 = \{ g \in G_2 : (e,g) \in K \}$. Show that:   $$H_1 \le G_1; \quad H_2 \le G_2; \quad H_1 \times H_2 \le K.$$      (ii) Suppose that $|G_1|$ and $|G_2|$ are coprime. Show that $K = H_1 \times H_2$.      (iii) Show that this result need not follow if $|G_1|$ and $|G_2|$ are not coprime.   I have done part (i). I was doing part (ii) and got stuck:  Since from above I showed that $H_1 \times H_2 \subseteq K$, now I only need to show that $H_1 \times H_2 \supseteq K$.  Let $(g_1,g_2) \in K$ where $g_1 \in G_1$ and $g_2 \in G_2$. Since $K \leq G_1 \times G_2$, we have $(g_1,e) \in K$ and $(e,g_2) \in K$. Hence $g_1 \in H_1$ and $g_2 \in H_2$.  Finally we have $(g_1, g_2) \in H_1 \times H_2$  As I haven't used the fact that order of G_1 and G_2 are coprime, there must be something fundamentally wrong with my proof.


Exception in thread "Thread-0" java.lang.NullPointerException at java.lang.Thread.run(Thread.java:748)

I'm getting Exception in thread "Thread-0" java.lang.NullPointerException.    this array is already printed before, I don't understand why int the second time it's throws this error. here is my code:    static Sensors[][] proximity_Sensors;     public static void main(String[] args)     {         StartGUI Quad_StartWindow=new StartGUI();          Quad_StartWindow.StartSimulation.addActionListener(new ActionListener() {              public void actionPerformed(ActionEvent e) {              Thread thread1=new Thread(new Runnable() {                     public void run() {                         if (ConnectToSimulator(1,Quad_StartWindow)!=-1)                         {                             ConnecSucc(1);                             getSensors(1);                             while (System.currentTimeMillis()-startTime < 1000000){                                  ReadSensor(1); // here the error                              }                         }                     }                 });              Thread thread2=new Thread(new Runnable() {                     public void run() {                         if (ConnectToSimulator(2,Quad_StartWindow)!=-1)                         {                             ConnecSucc(2);                             getSensors(2);                             while (System.currentTimeMillis()-startTime < 1000000){                                 ReadSensor(2);                             }                         }                                           }                 });                  thread1.start();                 thread2.start();                             }          });         Quad_StartWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);         Quad_StartWindow.setSize(500, 250);         Quad_StartWindow.setTitle("Drone window");         Quad_StartWindow.setVisible(true);     }   public  synchronized static void getSensors(int j)         {             proximity_Sensors=new Sensors[2][8];             for(int i=0;i<8;i++)             {                 proximity_Sensors[j-1][i]=new Sensors();                 String nameObject="Proximity_sensor"+j+"_"+i;                 vrep.simxGetObjectHandle(clientID, nameObject, proximity_Sensors[j-1][i].intObjHandle, vrep.simx_opmode_oneshot_wait);                 System.out.println(proximity_Sensors[j-1][i].intObjHandle.getValue() + " " + j+" "+nameObject+" "+i);              }         }         public  synchronized static void ReadSensor(int j){              for(int i=0;i<8;i++)             {                 ret=vrep.simxReadProximitySensor(clientID,  proximity_Sensors[j-1][i].intObjHandle.getValue(), proximity_Sensors[j-1][i].mLightSensorDetectionState, proximity_Sensors[j-1][i].detectedArray, proximity_Sensors[j-1][i].ObjectDetected, proximity_Sensors[j-1][i].detectedSurfArray, vrep.simx_opmode_oneshot_wait);             }         }      and another question, why thread 1 gets the data that thread 2 should get?


Emails sent via Automation not in Individual email results

I'm new to Marketing Cloud. I started with Journey Builder and now moving to Automation Studio. Emails sent through a journey are synced with Contacts in Sales Cloud in the Individual Email Result related list. But emails sent through an Automation are not. Is this normal? Is there something I missed?


Rooks Attacking Every Square on a Chess Board

8 rooks are randomly placed on different squares of a chessboard. A rook is said to attack all of the squares in its row and its column.  Compute the probability that every square is occupied or attacked by at least 1 rook.  The first step I took was to state that there are $64C8$ ways to decide how to place the 8 rooks on the chessboard. Next, I tried to experiment with a physical chessboard to see how this could be done. The only way I found that every square on the board can be attacked is if one rook is in either every horizontal row or every vertical row. Therefore, there are $2 * 8^8 - 2$ ways to place the rooks. To clarify, it is "-2" because the diagonals are counted twice.   Is there a case that I overlooked, or did I solve the problem correctly?  Thanks,  You Know Me......


Why a holomorphic function satisfying these conditions has to be linear?

Let $\Omega$ be a bounded open subset of $\mathbb{C}$ and $f:\Omega\rightarrow\Omega$ be holomorphic in $\Omega$. Prove that if there exists a point $z_0$ in $\Omega$ such that $$f(z_0)=z_0~~~~\text{and}~~~~f'(z_0)=1$$ then $f$ is linear.  Please give some hints. Thanks in advance!


An object is missing when rendered. It is not restricted, clickable, and can be seen in the 3D View. I have searched the internet, and this forum as well but found nothing.  I have provided 2 screenshots if I ever did something wrong Please tell me when you need another screenshot of something.


Does the management or the Welcome Wagon care to know about activity that makes users want to leave their platform?

Does the management or the Welcome Wagon care to know about activity that makes existing users want to leave their platform or is the goal only to welcome new users?  I would like to post some simple suggestions and cases but in the past I've been attacked for it.


Can I make custom bokeh shape using a 18-55mm Nikkor lens?

Custom bokeh shapes need a large aperture. The max aperture my lens can reach is f3.5. Is it big enough for a custom bokeh? I tried but it doesn't work.


I am new to Java, so please bear with me. I've tried to get a button to open up a new frame called AboutFrame, but whenever I press the button nothing happens.  I implement the ActionListener first:  class MainFrame extends JFrame implements ActionListener {   Then I set the button (after the usual super("blabla");...)  JButton info = new JButton("About Failsafe");     info.addActionListener(this);   And then:  public void actionPerformed(ActionEvent event) { String command = event.getSource().toString();     if (command == "info") {         AboutFrame abt = new AboutFrame();     } }   So what am I doing wrong here? I can't see any mistakes..


How do I know which edition of Dungeons and Dragons (D&D) the books I'm looking at are for?

, each of which has loads of rules, source, and splat books.  But how do I know which edition the books I'm looking at are for?  A lot of the time the ones in hobby stores are wrapped up, or you'll buy from elsewhere that doesn't say in the description, and the covers just say D&D.  Is there a way to identify which edition of D&D the books I'm buying are for, either from the cover or some description in the book?  For the purposes of this question I'm asking about core rule books only. Eg. PHB, MM, and DMG. Hopefully the answer to this can be carried over to other books.


Capitalize first letter ONLY of a string in Python

I'm trying to write a single line statement that assigns the value of a string to a variable after having ONLY the first letter capitalized, and all other letters left unchanged.  Example, if the string being used were:  myString = 'tHatTimeIAteMyPANTS'   Then the statement should result in another variable such as myString2 equal to:  myString2 = 'THatTimeIAteMyPANTS'


Ive heard many theories one being that a 0 looks like an egg and the french word for egg sounds like love and after time became just that, but this is just one theory. Does anyone know the actual reason why 0 in tennis is called love?


I have a multiple setups with 6 monitors, but would like to explore using 1 monitor/tv but act like 6 monitors. (i.e. you max a window it does not go over the whole screen just one of the 6 sections). Please let me know what info you need any i will be happy to give what is needed.


We're a bunch of friends building an RC boat, this may sound stupid but I had an argument with a friend where he insisted that his design will work.  Basically, he's saying that by putting a powerfull fan and a piece of tissue as a sail, when the fan will blow air into it, the boat will move.  What do you think?


Trying to compute the first five coefficients of the Laurent series for $$\frac{1}{e^z-1}$$ centered at the point $0$. I'm not seeing a way to use the geometric series due to the exponential. Any ideas?


Hey having some trouble trying to maintain transparency on a png when i create a thumbnail from it, anyone any experience with this? any help would be great, here's what i am currently doing:  $fileName= "../js/ajaxupload/tees/".$fileName;  list($width, $height) = getimagesize($fileName);  $newwidth = 257; $newheight = 197;  $thumb = imagecreatetruecolor($newwidth, $newheight); imagealphablending($thumb, true); $source = imagecreatefrompng($fileName); imagealphablending($source, true);  imagecopyresized($thumb, $source, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);  imagesavealpha($thumb, true); imagepng($thumb,$newFilename);


All Stack Exchange emails come from Stack Overflow

When I get an email about an inbox notification on any Stack Exchange site it comes from "Stack Overflow <do-not-reply@stackoverflow.email>"   And I think they should at least change the name displayed on the front of the email if not the email address itself to stackexchange.email.   Also, I think they should remove the link at the top of all SE notifications which links to Stack Overflow and change it to link to Stack Exchange instead.


For a submitted paper, what does the status "Evaluating Recommendation" mean and how long does it last?


Error When Install Ubuntu on Virtual Box

I`m wanting to install Ubuntu 13.10 on virtual machine(VirtualBox) but I got an error when I want to boot Ubuntu . .  This Kernel reguires the following features not pasent on the CPU:  pea Unable to boot - olease use a kernel appropriate for your CPU   Can anybody help me?


Variance of a distribution's product with itself

I have a distribution $X$. By playing around with random samples from $X$, I've determined that $Var(X^i) > Var(X)$ where $i > 1$. However, I can't seem to find a formula for the expected variance of $X^i$, or why it should be greater than $Var(X)$.  Moving away from normal distributions, should it generalize that the scale parameter of any $X^i$ will be greater than $X$?


What level of canon is the lore in Star Wars: The Old Republic?

I was wondering: there is a lot of lore in Star Wars: The Old Republic, and some events could be seen as contradictions. What level of canon is given to this game?


I need to prove that  $\lim_{n\rightarrow \infty} \int_0^{n^2} n\sin(x/n) e^{-x^2}dx=1/2$  I tried substituting $t=\frac{x}{n^2}$, but it was not very useful because I can't find a bounding function for the integrand which does not depend on $n$ in order to apply the Dominated convergence Theorem. It would not help anyway as the limit of the integrand is zero which would give the wrong result.  I think I need a good substitution, if anyone could give a hint about that it would be very appreciated!


Can I apply for a second Indian-Tourist Visa? Is there any time gap needed?

I am currently in India. I have a 6 months tourist visa, multiple entries, and my visa will expire soon.  Can I apply for a new visa from India or Sri Lanka? Or I have to go back to my country (Romania) and apply there? Is there a time gap between the expiry date of my visa and the moment I can apply for a new one?    (i.e. when my visa expires, I can go to ski lanka or my country and in 2 weeks to apply for a new tourist visa?)  Thank you very much!


Cannot launch software centre, neither update

m@samsung:~$ sudo rm /var/lib/apt/lists/* -vf [sudo] password for m:  rm: cannot remove `/var/lib/apt/lists/partial': Is a directory m@samsung:~$ sudo apt-get update N: Ignoring file 'gnomebaker.lis' in directory '/etc/apt/sources.list.d/' as it has an invalid filename extension E: Malformed line 1 in source list /etc/apt/sources.list.d/gnomebaker.list (URI parse) E: The list of sources could not be read. m@samsung:~$


Are there any purely semantic proofs of the compactness theorem that don't use the full axiom of choice?

Using Godel's completeness theorem, it can be shown that the compactness theorem is equivalent to the ultrafilter lemma. The compactness theorem can also be proven using ultraproducts and Los's Theorem, but it requires reference to the full axiom of choice. My question is: are there any known proofs of the compactness theorem that make no reference to syntactic provability, that use no choice principles stronger than BPIT?


`zsh` and `bash` handle command output differently

In zsh:   % RESPONSE=$(ping -c 1 raspberrypi4b.local) % echo $RESPONSE | grep "% packet loss"  1 packets transmitted, 1 packets received, 0.0% packet loss   But in bash it's different:   $ RESPONSE=$(ping -c 1 raspberrypi4b.local) $ echo $RESPONSE | grep "% packet loss" PING raspberrypi4b.local (192.168.1.184): 56 data bytes 64 bytes from 192.168.1.184: icmp_seq=0 ttl=64 time=1.376 ms --- raspberrypi4b.local ping statistics --- 1 packets transmitted, 1 packets received, 0.0% packet loss round-trip min/avg/max/stddev = 1.376/1.376/1.376/0.000 ms   Yet when I run ping directly, the output is formatted identically:   In zsh:   % ping -c 1 raspberrypi4b.local PING raspberrypi4b.local (192.168.1.184): 56 data bytes 64 bytes from 192.168.1.184: icmp_seq=0 ttl=64 time=7.526 ms  --- raspberrypi4b.local ping statistics --- 1 packets transmitted, 1 packets received, 0.0% packet loss round-trip min/avg/max/stddev = 7.526/7.526/7.526/0.000 ms   in bash:  $ ping -c 1 raspberrypi4b.local PING raspberrypi4b.local (192.168.1.184): 56 data bytes 64 bytes from 192.168.1.184: icmp_seq=0 ttl=64 time=7.613 ms  --- raspberrypi4b.local ping statistics --- 1 packets transmitted, 1 packets received, 0.0% packet loss round-trip min/avg/max/stddev = 7.613/7.613/7.613/0.000 ms   It seems that bash is ignoring the newlines that are in the output of ping, but perhaps the variable assignment has caused this? In either case, can I get bash to handle this string in the same way that zsh does?


Confusion related to predictive distribution of gaussian processes

I have this confusion related to the predictive distribution of gaussian process. I was reading this      I didn't get how the integration gave that result. What is P(u*|x*,u). Also how come the covariance of the posterior distribution is $\sigma^2(\sigma^2I+K)^{-1}K$


Term or phrase describing action occuring when not watching

I am an IT professional. More specifically in automation. I am looking for a term or phrase that describes the event when either:  a. you are watching something closely and the issue doesn't occur  or  b. you are not watching something at all and the issue does occur


SQL Server - Best way to get identity of inserted row?

What is the best way to get IDENTITY of inserted row?  I know about @@IDENTITY and IDENT_CURRENT and SCOPE_IDENTITY but don't understand the pros and cons attached to each.  Can someone please explain the differences and when I should be using each?


Landscape topography from grayscale image

Trying to do some golf course layouts in 2.73a. Would like to use topo elevation info. Currently have grayscale .jpg of site - top view. How do I get this into Blender as a "lumpy" plane?


I need pointing to an accurate up to date method to install Wordpress. I also need details on setting up Apache for it. There is NO official help or support that I can find. Is there anything else beyond the virtual host file and the /etc/hosts edit? How exactly should they be configured? My ip just leads me to the Apache test page, how to I get it beyond that into the sub directory?


How to Add Docusign Signature and Date Tags to Dynamic PDF Creation

I'm trying to determine if it is possible to embed the Docusign Signature and Date tags into apex code that dynamically generates a PDF file using XMLStreamWriter. The PDF file is generated from the Quote by clicking a button that runs apex code and builds the PDF content using XMLStreamWriter and sends the XML using a callout to an external service endpoint (managed package) which returns the PDF and attaches the PDF to the Quote. At that point, it is the normal process of sending the Quote PDF via Docusign, however, the Signature and Date tags are missing from the PDF document for signing, which requires the user to drag the signature and date tags onto the PDF form the Docusign interface before hitting send. Ideally, having the signature and date tags automatically included in the PDF is the goal. I'm trying to determine if this is even possible and, if so, what approach would need to be taken to accomplish this. Has anyone encountered this type of use case? If so, what approach was taken? Thanks.


I would like to make a hanzi grid for practicing Chinese characters, like this one:   I am able to make the table with the arydshln package, like this:  \begin{tabular}{|c:c|c:c|c:c|c:c|}   \hline   & & & & & & & \\   \hdashline   & & & & & & & \\   \hline   & & & & & & & \\   \hdashline   & & & & & & & \\   \hline \end{tabular}   but how can I write the characters over the table?


How to detect mojibake (garbled text) in Python?

if you run this in python     print 'Äppleß','Äppleß'.decode('latin-1').encode('utf-8')   thats a mojibake (garbled text due to incorrect encoding/decoding) but python does not raise an error.  I want it to throw an error in the case of a mojibake.  I have heard of things like this that can help:   any other ideas or experience on shortcuts?


Is there a way to not update pygame frames is nothing has happened?

I am designing a game in pygame at the moment and i was thinking how low my framerate was (an average of 7 fps). I investigated further and did convert_alpha() for all my images and I wondered if there was a simple way to make it so that if nothing in the window had changed the frames would not update, therefore this may result in a higher framerate.  As I said earlier, I did convert_alpha() to all of my images yet my framerate did not increase whatsoever. I have google other ways and I thought what I really needed was a program controlling whether or not I needed to update all the frames.   I just need some sort of program that can do this for me. Any sort of help would be greatly apprieciated!


What is the appropriate damage for landing on someone's head from a certain height

Is there guidance in any of the source books on damage taken when something falls on a creature?  For my new Loxodon Monk (you may have read about him) I'm planning on Shadow Stepping to a ceiling (which we verified is possible) and simply dropping on my enemies head.  Our current "homebrew modifier" is 1D10 per 100lbs if at least 10 feet in the air. We haven't been able to find anything official. Maybe we just missed it.


Which file system do I select for sharing files between Windows and Ubuntu?

Presently in the install (USB stick) for 32-bit Ubuntu 12.04.1.  Want to have dual-boot capabilities between Windows 7 and Ubuntu.  Have partitioned hard drive with Windows System (sda1), Windows OS (sda2), Ubuntu (sda3 - with ext4 file system and a "/" mount point), swap (sda4) and need to know what file system to select for the remaining free space (storage) partition with a /home mount point?  I presume it to be either FAT32 or ext4, yet I need to be sure that it enables cross-sharing of documents/directories with both Windows 7 and Ubuntu operating systems.  Also, is FAT32 an NTFS type of system?  Thanks in advance.


Login method returning null pointer exception

I'm currently doing login form with Swing using Oracle database. But my code returned NPE when I try to compare both my username and password field inputs to my login() method. Here is portion of my codes.  LoginUI.java  // field declaration private JFrame frame; private JTextField username; private JPasswordField password; private JButton login; private AccessDA access;  // portion of login codes JLabel lblUsername = new JLabel("Username:"); lblUsername.setFont(new Font("Tahoma", Font.PLAIN, 14));  username = new JTextField(); username.setColumns(10);  JLabel lblPassword = new JLabel("Password:"); lblPassword.setFont(new Font("Tahoma", Font.PLAIN, 14));  password = new JPasswordField(); password.setColumns(10);  login = new JButton("Login"); login.setFont(new Font("Tahoma", Font.PLAIN, 14)); login.addActionListener(new ActionListener(){      @Override     public void actionPerformed(ActionEvent e) {          String u = username.getText();         char[] p = password.getPassword();          if(access.login(u, p)){             JOptionPane.showMessageDialog(null, "Success");         } else {             JOptionPane.showMessageDialog(null, "Incorrect credentials");         }      } });   AccessDA.java, login() method  public boolean login(String username, char[] password) {  boolean status = false; Connection conn = null; PreparedStatement pst = null; ResultSet rs = null;  try {     conn = ConnectionProvider.getCon();      pst = conn             .prepareStatement("select * from users where user_name=? and user_pass=?");     pst.setString(1, username);     pst.setString(2, String.valueOf(password));      rs = pst.executeQuery();     status = rs.next();  } catch (Exception e) {     System.out.println(e); }  return status; }   Stack trace  Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at com.strawberry.gui.LoginUI$2.actionPerformed(LoginUI.java:85) at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018) at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341) at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402) at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259) at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252) at java.awt.Component.processMouseEvent(Component.java:6516) at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)   Where LoginUI.java:85 is if(access.login(u, p)){.  How do I get the values from the field and compare them to my login() method?  Thanks.


Proper SE site to ask about cloudcompare question

my question tile is :       i have compared two dental model like this:            and the output only give me the 254 point , so i like to know how   could i get more point as output, also what is the means of the   columns ins the csv file like this:      Class     Value   Class start     Class end            Thanks.   so i like to know where is the proper SE site to ask it there?  Thanks.


its giving true for both values in boolean. how to improve the code?

import java.util.Scanner;  class Pal {     public static boolean Palindrome(StringBuffer str) {         StringBuffer str1 = str.reverse();         System.out.println(str1);         if (str == str1) {             return true;         } else {              return false;         }     }      public static void main(String args[]) {         System.out.println("Enter a string");          StringBuffer str = new StringBuffer();         Scanner input = new Scanner(System.in);         str.append(input.nextLine());          boolean result = Palindrome(str);         System.out.println(result);     } }   How sholud I improve my code such that values come out to be perfectly correct?


I applied for a Greek residence permit two months ago and got my blue paper. In the meantime, I returned to my home country and my Schengen has expired.  Now, I will go to Athens to collect my residence permit and I will travel for the first time with my blue paper. I just want to make sure that there will be no problems while entering Greece. Can anyone who has entered Greece with a blue paper share their experience?


Does the LHC see electro-weak symmetry breaking?

The energy scale of  is around $160$ GeV. But the LHC has a centre of mass energy of $7$ TeV... so do they see processes involving the $W^1, W^2, W^3$ and $B$ fields, before spontaneous symmetry breaking and mixing into the well-know massive gauge bosons + photon?


Can servers be synchronised to share the same configurations?

I have three VPS' running on separate hosts. They've had CentOS 5 installed on them at various points and I assume all run with slight variations of Webmin, PHP, MySQL etc.  I've started to notice slight differences in how each server does tasks that are the same (eg, a Wordpress plugin might work on one VPS, but not on another - just as a general example).  I'm still quite new to Linux and server admin, so clearly there's a lot to learn about housekeeping etc, but I'm quite happy that I've managed to get the servers up and running and serving pages!  What I'm wondering, though, is whether or not there's an easier way of managing those three separate servers, so that they all run an identical configuration. Is it possible to synchronise/ mirror the configuration of one server across several others and if so, how?  I'm running CentOS 5 with Webmin and Virtualmin, as mail and web servers.


The  states that:     Since 1.0.4, case insensitive regular expressions can be used by prefixing the pattern with ~*.   And gives the example:  map $uri $myvalue {     /aa                   /mapped_aa;     ~^/aa/(?<suffix>.*)$  $suffix; }   I updated to nginx/1.2.7 to make use of this, and naive regexes work okay, but variables don't. When I try the above syntax I get the error:  nginx: [emerg] pcre_compile() failed: unrecognized character after (?< in "^/aa/(?<suffix>.*)$" at "suffix>.*)$"   I also tried the following syntaxes, but none of them worked:  ~^(.*)$  $1; ~^(.*)$  \1;   but neither of them worked either.  Does anyone know how to get variables to work in regular expressions in HttpMapModule?


The East German antique lens, Zeiss Biotar 75mm, is famous for producing a swirling, water-like bokeh as illustrated in the photo below:    What optical materials and/or design cause this effect, which appears to be a coma aberration? Is it characteristic of any double Gauss design or is there something unique about the Biotar that creates it?


For a finite group $G$ and a subgroup $H,$ Lagrange's theorem says that $|G|=|G:H||H|,$ where $|G:H|$ is the number of cosets of $H$ in $G.$ My question is for any subgroup $H$ can we find another subgroup with order $|G:H|$?


I've been pretty frustrated lately with my poor integration skills. A lot of times I find that in my math or physics classes I understand the concepts behind a question, reduce it to an integral, and then find myself unable to solve it. Yet some people both on this board and at my university are deft hands at solving complicated integrals with a variety of tricks. I'd really like to get better at integrals and start approaching their level. I was hoping that there might be suggestions of workbooks or textbooks that are designed purely on increasing the reader's ability to solve difficult integrals, and also suggestions on a good general philosophy to take to get better at this as well.   Also, I'm unsure if this is the wrong place to ask this question. If so, I apologize and I'll remove the question.


Prove that $$\lim_{n\to\infty}\frac{(n+1)(n+2)\cdots(2n-1)2n}{n^n}=\infty$$   I saw that $$\frac{(n+1)(n+2)\cdots(2n-1)2n}{n^n}=\prod_{i=1}^n\left(1+\frac in\right)$$ I think I can use squeeze law, but I'm not sure. Can you give me a hint?


How to identify 32bit applications on macOS without running each one?

With macOS 10.13.4 Apple will start to show a warning if a 32bit application is started, and it is assumed that with 10.14 32bit applications will not run at all. Starting each application to see whether it is 32bit might be cumbersome, so if I want to prepare for the migration early how can I easily (via GUI or Terminal) assemble a list of all 32bit applications on my system?


For e.g- in $U(10)=\{1,3,7,9\}$ are elements and $3$ & $7$ are generators but for a big group like $U(50)$ do we have to check each and every element to be generator or is there any other method to find the generators?


PHP arrays work differently for objects vs values

Here's my code:  $words = array(); $word = "this"; $words[] = $word; $word = "that"; $words[] = $word; print_r($words);  class word{     private $text;     public function __construct($word){         $this->text=$word;     }      public function setWord($word){         $this->text=$word;     } }  $class_words = array(); $word = new word("this"); $class_words[] = $word; $word->setWord("that"); $class_words[] = $word; print_r($class_words); exit;    Here's the output:  Array (     [0] => this     [1] => that ) Array (     [0] => word Object         (             [text:word:private] => that         )      [1] => word Object         (             [text:word:private] => that         )  )   I expected the second output to match the first in that the array should store 'this' and 'that'.  It seems array_name[] = <item> makes a copy to the item when it's an array of values but not so when it's an array of objects.  How do I make it copy the object to the array instead copying a reference to the object?  Do I need to create a new object each time I need to add an object to the array?


Weird linking error in C++ with gcc compiler

I faced a weird linking problem when trying to compile my source code. I paste my code below for better explanation.  LinkedList.h  #ifndef _LINKED_LIST #define _LINKED_LIST  #include <iostream> #include "ListInterface.h" #include "Node.h" #include "PrecondViolatedExcep.h"  template<class ItemType> class LinkedList : public ListInterface<ItemType>{............ //There is the some code here, but thats not the point so i don't  #include "LinkedList.cpp" #endif   main.cpp  #include "LinkedList.h"  int main() {     LinkedList<int> list; }   You can see that under the LinkedList.h header file, i included this line #include "LinkedList.cpp at the bottom.  So now i can compile like this: g++ main.cpp -o main. This give me no problem at all the program works correctly.  But the linking problem appear when i remove this line #include "LinkedList.cpp at the bottom of LinkedList.h header file. And i compile like this: g++ main.cpp LinkedList.cpp -o main. Theoretically this should not be a problem, i done this most of the time with other projects. So this problem is kind weird for me. Can anyone pointing out what is the cause of this?


If a user is not getting the answers he needs, could I ask him to send me an email or something or pm me in skype?


Converting Older United States Dollar Bills

I received from my Dad 150 American Dollars about 12 years ago. I never have thought to change this money but a few days I tried change it in a currency exchange in Sydney and the guy didn't change it because the series are old.     What do I have to do to change this money?


How to check if a file exists in another folder

I have this file in the following path:  A = I:\user\me\count.txt   I want to check whether or not the count.txt exists in another path because I want to tag them as existing in the other folder.  As an example, lets say:  path1 = I:\user\me\personal\ path2 = I:\user\me\work\


I am attempting to draw a squiggly circle in order to delineate an area of a figure, but in a manner that emphasizes the arbitrariness of the precise boundary - something like the circle below, but more distorted and random. I cannot figure out a good way of approaching this with TikZ - any suggestions?


Minimum between two functions $\min(f(x), g(x))$

I found the following equation in a Blog (), which could help me a lot solve a certain problem:  $\min(f(x), g(x))=\frac{f(x)+g(x)–|f(x)–g(x)|}{2}$  The problem is I don't know, how the author came up with that and I never saw it in a textbook or someone else using. Does somebody may have an idea where it comes from or how to verify it.   cheers


#include<iostream> using namespace std;  void callByReference (int &);    //Function Prototype  int main() {   int num;                         //Variable Declaration   cout<<"Enter number";    cin>>num;   callByReference(num);             //Function Definition   cout<<"Number after triple is "<<num<<endl;   return 0; }  void callByReference (int & cRef)   //Funciton Definition {   cRef=cRef*cRef*cRef; }   If we are passing address in cRef then address should be multiplied thrice. How the value is multiplied thrice?


How can I prevent Windows from overwriting GRUB when using a dual-boot machine

I've been reading a lot about dual-booting, and it seems as easy as loading Windows and then loading Linux with GRUB, but everybody says that Windows loves to trash GRUB when it gets the opportunity. What are some steps I can take to prevent this from happening (other than using Windows' bootloader, I want to keep this as simple as possible)?


Help Finding a Fantasy (I think) novel - It Had A Snake eating its Tail on the Cover

Never fear I can in fact remember more about it than that! The cover was black and it had a silver snake eating its own tail on the cover. The book was about a boy who is hired by a company to travel (with a girl and another boy (the drummer)) to another world/alternative reality and there they discovered another girl who turned out to be his dead twin sister.   He was some hero or something and they found something out about the company they were hired by and at one point he was almost killed but got a scar next to his right (or maybe left) eye that made him or marked him as the seer? His twin gave him a bracelet shaped like a snake biting its own tail and that meant something important... The Snake was also the symbol/logo of the company.   In the end he went home and spoke to him mom about his twin and I remember it being the first book in a series.


While solving for the curl of the magnetic field($\vec \nabla\times \vec B = \mu_0 \vec J$), I got one formula which is written as $$\vec \nabla \cdot \frac{\hat r}{r^2} = 4\pi \delta^3 \vec r \tag{1}$$ and while solving for the verification of the Poisson's equation, I found the formula as follows $$\vec \nabla^2\frac{1}{\mid{\vec r - \vec r\:'}\mid} = -4 \pi \delta^3 (\vec r \:-\:\vec r\:')\tag{2}$$What are these equations called?  How do we get these equations (1) and (2)?  Can you please provide me the proof of these equations?


Get the shift based on entry time in php

Hello everyone i am working on a employee attendance system and i have the following issue.  I want to get the shift based on entry time for example if the worker is starting work betwen 5am and 10 am to be the shift 1 if it enters betwen 11 am and 3pm to be the shift 2 and if it enters betwen 7pm and 11pm to be the shift 3.  Here is what i tryied but i get stuck on getting the current time  $shift= 1;         $stmp = time();         //if($PR_Come <= $5:00 && $PR_Come>= $8:00) { $shift=1;}         //if($PR_Come <= $11:00 && $PR_Come>= $16:00) { $shift=2;}         //if($PR_Come <= $19:00 && $PR_Come>= $23:00) { $shift=3;}         $PR_Come = date("Y-m-d H:i:s", $stmp);         $PR_Year = date("Y",$stmp);         $PR_Month = date("m",$stmp);         $PR_Day = date("d",$stmp);         $sqlcmd = "INSERT INTO $dbname.ppresence (PR_WorkerPTR, WORKER_Name, PR_Come, PR_Year, PR_Month, PR_Day, shift) VALUES "         ."('".ppaddslashes($workerrow["WORKER_ID"])."', '".ppaddslashes($workerrow["WORKER_Name"])."', '".ppaddslashes($PR_Come)."','".ppaddslashes($PR_Year)."','".ppaddslashes($PR_Month)."','".ppaddslashes($PR_Day)."','".$shift."')";         mysql_query($sqlcmd);   PS Sorry for my bad english. :)


When do you receive a bonus action and reaction?

When you start combat, after determining surprise and establishing positions; you roll for initiative. At this point, do all combatants have a reaction or bonus action even if they are not first?  For example: "X" is talking to "Y" when they break out in a fight. The fight begins with X and Y standing adjacent to one another. X is first in the initiative order and decides to move away then attack.  Does Y have the ability to use a reaction (Attack of Opportunity)? If yes, can he use another reaction after his turn?  In a sense I am asking if reactions can be used on a per round basis or specific to the character.  If it were a per round basis, Y could perform an Attack of opportunity and on his turn will not be able to ready an action.  If it is specific, he won't be able to perform an Attack of Opportunity on X's turn, but would be able to if he moves so he is adjacent to X and X moves away on his turn.  Or can Y use a reaction to attack, then on his turn, gains back a reaction?


as shown in the screenshot below, sins I installed some add-ons I opened blender and I found that the add-ons preferences won't show up, I tried to reset preferences to factory, and I  reboot my PC and I even reinstalled it and the issue remains unsolved. what can cause this problem? and what solutions you propose? thank you blender version 2.90.1


Change keyboard shortcuts in Microsoft Excel 2016 in Windows

In Excel 2016, I would like to change the keyboard shortcut for the Search command from CTRL+B to CTRL+F so that this command has the same keyboard shortcut as in other programs. However, I could not find how to do this.  In Word, to do this, I can right click on the ribbon, select "Customize ribbon" and click on the button "Keyboard shortcuts: Customize" like in the screenshot:    However, in Excel, this button doesn't exist, or at least I couldn't find it:    I found a similar issue with Excel in Mac , but it didn't help me since the answers suggested using features that are specific for Mac and I'm using Windows.  How can I change keyboard shortcuts in Excel 2016 in Windows?


fasboot devices not getting attached xiaomi mi a3 no sound of attaching no nothing

I have the Xiaomi Mi A3 and I'm currently on both phone and PC latest stock update. I am using Windows 10 20H2 and I have tried everything – but still don't get it. I tried another Mi A3 and it got attached normally. I've tried installing all kind of drivers and different ports, nothing. When suddenly it worked and I installed the stock ROM – but because the stock ROM is kinda laggy and ugly I want to change it. But I can't because I am also on stock recovery and I can't install another recovery because my device isn't recognized in fastboot mode. My device is recognized in adb mode and in edl mode as well, only not in fastboot.


How to prove that :  9 | $a_k+... +a_1+a_0$ implies that   9 | $a_k 10^k +... +a_1 10^1 + a_o 10^0$  where | denotes the divisibility sign (that is, I need to prove that if $a_k+... a_1+a_0$ is divisible by 9 then so is $a_k 10^k +... a_1 10^1 + a_o 10^0$).


How to show that the Shannon Entropy is well defined?

The Shannon entropy $I(P)$ of a probability vector $P \in [0,1]^{n}$ is given by $I(P) = - \sum_{\gamma = 1}^{n} P_{\gamma} ln(P_{\gamma})$ I want to show that $I(P)$ is well defined i.e., $lim_{x \rightarrow 0} xln(x) = 0$ Does someone have any idea how can I do that? Thanks!


How to fix a fake USB flash drive that reports more space than actually exists?

I bought a USB flash drive that reports it has more space than it really does.   How can I determine how much space it really has? Can I format it properly if I can get the above answer? Should I just return it and not try to salvage it?


How to delete the intersecting part of two objects?

As you can see in my image there are two circles kept on the hexagon. I want to know how do I delete the intersecting part of circle and hexagon which i marked in yellow ovals..??


Is there any difference when I say I wish I were rich or I wish I had been rich?


Derivative of $\sin_dx$ when x is measured in degree

Find the derivative of $\sin_d x,$ if $\sin_d x$ is the sine of $x$ where $x$ is taken to be in degrees.   please help me out solving this math question


What is the latest definition of energy?

So I will probably be screwed blued and tattooed for many reasons,  wrong forum,  nebulous question, etc. ,but aside from all available definitions what is the latest thinking on "what IS energy "


Issue with Vectors and custom classes in c++ with trivial constructor

I am having an issue using vectors with a custom class that I am creating. Here is my code  vector<image> frames;   int i = 0; while (i < n) {   image tempImage;   tempImage.read(fullname);   frames.push_back(tempImage); }   And the constructor for image is just image() {};  I am sure I am missing something simple, but I cannot figure out what it is. Here are my errors  /usr/include/c++/4.2.1/ext/new_allocator.h:107:20: error: no matching constructor for initialization of 'image'   { ::new(__p) _Tp(__val); }                ^   ~~~~~ /usr/include/c++/4.2.1/bits/stl_vector.h:604:20: note: in instantiation of member function   '__gnu_cxx::new_allocator<image>::construct' requested here         this->_M_impl.construct(this->_M_impl._M_finish, __x);                       ^ video.cpp:50:10: note: in instantiation of member function 'std::vector<image, std::allocator<image> >::push_back'   requested here             frames.push_back(tempImage);                    ^ ./image.h:25:4: note: candidate constructor not viable: 1st argument ('const image') would lose const qualifier image(image &img); ^ ./image.h:24:4: note: candidate constructor not viable: requires 0 arguments, but 1 was provided image(); ^ In file included from video.cpp:1: In file included from ./video.h:6: In file included from /usr/include/c++/4.2.1/vector:73: /usr/include/c++/4.2.1/bits/vector.tcc:252:8: error: no matching constructor for initialization of 'image'       _Tp __x_copy = __x;           ^          ~~~ /usr/include/c++/4.2.1/bits/stl_vector.h:608:4: note: in instantiation of member function 'std::vector<image,   std::allocator<image> >::_M_insert_aux' requested here       _M_insert_aux(end(), __x);       ^ video.cpp:50:10: note: in instantiation of member function 'std::vector<image, std::allocator<image> >::push_back'   requested here             frames.push_back(tempImage);                    ^ ./image.h:25:4: note: candidate constructor not viable: 1st argument ('const value_type' (aka 'const image')) would   lose const qualifier image(image &img); ^ ./image.h:24:4: note: candidate constructor not viable: requires 0 arguments, but 1 was provided image(); ^ ./image.h:26:4: note: candidate constructor not viable: requires 2 arguments, but 1 was provided image(int rows, int columns); ^ 2 errors generated.


filter products by product option value (Mysql query)

id | product_id | option    |  option value ------------------------------------------- 1  |    3       |    size   |   m 2  |    3       |    color  |   red 3  |    3       |    brand  |   apple 4  |    5       |    color  |   red 5  |    5       |    weight |   16m 6  |    6       |    size   |   m   i am get two product product_id [3,5]  now i am filter this products with option value  my filter option_value [m] here, m option_value presence in product_id 3 but not presence in product_id 5, so only show product_id 3  Again, filter option_value [red] here, red option_value presence in product_id 3 and 5, so all my gets products are show product_id 3,5  Finaly, filter option_value [m,red] here, m and red option_value presence in product_id 3 but m option_value presence in product_id 5 and red option_value not presence in product_id 5, so show product_id blank That means, i get that products who's option value are same as filter option_value  how to write this mysql query?


I am an undergraduate student - just started to learn about group theory, ring theory and module theory. I am self studying from the book "Basic Abstract Algebra" by P.B.Bhattacharya, S.K.Jain, S.R.Nagpaul. Prof said that this book is written in an uncomplicated manner but i found the statements in it with more hints rather than complete proofs. What are your thoughts about this book? Our prof also suggested Abstract Algebra by Dummit and Foote - but i found it quite bulky. Please enlighten me with your thoughts as i am very much lost - which one to follow. Thank you.


I'm writing this question because I love Stack Exchange, but I'm a little discouraged from what is happening recently :( I'm making very useful questions and the answers the people give to me are amazing. But... The problem is (for me) that for the past two months I haven't received any upvote; conversely those who respond have three upvotes easily... My questions are full of images and even GIF images to try to explain where my problem lies. I always try to make sure that they understand where the problem lies without having to make an effort to read my mind. But it seems that everything is useless, because no one gives me an upvote. Ok, I'm happy because I have an answer, ...but if you answer the question, couldn't you also give me an upvote maybe?  So what could I do to have some upvotes? What changes have you made to make your questions more meaningful and pleasing to the answering audience?  All ideas are welcome. Also only to find out if you too are having this problem or not... Thanks for the attention.


So, I have the following code written in Java which uses the Stanford CoreNLP library to perform sentiment analysis of tweets.   import java.util.*; import java.util.List; import java.util.Properties; import edu.stanford.nlp.ling.CoreAnnotations; import edu.stanford.nlp.neural.rnn.RNNCoreAnnotations; import edu.stanford.nlp.pipeline.Annotation; import edu.stanford.nlp.pipeline.StanfordCoreNLP; import edu.stanford.nlp.sentiment.SentimentCoreAnnotations.SentimentAnnotatedTree; import edu.stanford.nlp.trees.Tree; import edu.stanford.nlp.util.ArrayCoreMap; import edu.stanford.nlp.util.CoreMap; public class NLPAnalysis  { static StanfordCoreNLP pipeline;  public static void init() {     Properties props = new Properties();     props.setProperty("annotators", "tokenize,parse,sentiment,pos");     pipeline = new StanfordCoreNLP(props); }  public static String findSentiment() {     Scanner sc = new Scanner (System.in);     String tweet = sc.next();     String SentiReturn = "";     String[] SentiClass ={"very negative", "negative", "neutral", "positive", "very positive"};      //Sentiment is an integer, ranging from 0 to 4.      //0 is very negative, 1 negative, 2 neutral, 3 positive and 4 very positive.     int sentiment = 2;      if (tweet != null && tweet.length() > 0) {         Annotation annotation = pipeline.process(tweet);          List<CoreMap> sentences = annotation.get(CoreAnnotations.SentencesAnnotation.class);         if (sentences != null && sentences.size() > 0) {              ArrayCoreMap sentence = (ArrayCoreMap) sentences.get(0);                             Tree tree = sentence.get(SentimentAnnotatedTree.class);               sentiment = RNNCoreAnnotations.getPredictedClass(tree);                          SentiReturn = SentiClass[sentiment];         }     }     return SentiReturn; }  public static void main(String[] args) throws Exception     {     System.out.println("Enter your tweet:");     String answer = findSentiment();     System.out.println("The Sentiment:"+answer);     } }   I have set the annotators to tokenize, parse, sentiment, pos based on a previous answer to a similar problem, but I still keep getting a NullPointerException at line 33: Annotation annotation = pipeline.process(tweet);.   Please help me with this issue. Thanks.


I am attempting to create my first 3D character just for practice. Being one of my first 3d models I going through the learning curve needless to say. In doing so I find myself creating many extra vertices. Where we will say 10 vertices on a rounded shape are spaced out on the equator and on the other north pole end of the edges they are very close. The close end could all be one vertex. Is it possible to say merge all points to one point and delete the rest?


I've found it in a book and assume it's got to be correct, but I cannot understand why the Past Perfect of I had been offered. Would was offered not have been clearer?  I explained that when I was in high school I had been offered a job teaching tennis at a local country club because I had been one of the best junior tennis players in the area


Why do airlines seat people the way they do?

Getting on a flight seems to be so inefficient.  I can understand allowing first class on first and their platinum class/silverstar/etc members.  They are loyal members and allowing the few individuals who meet this criteria on first seems fine since it is only a small group of individuals.  But then there is a total breakdown in the system.  First, they do it by group.  But whatever group you may be doesn't really have any bearing on where you sit.  In addition, everyone clumps up near the counter. Then before everyone on the flight has stowed their luggage, they call the next group, which leads to people being stuck in the jet bridge. If there was an emergency in the jet bridge that didn't allow people to travel back to the terminal, it would seem so much worse compared to having most people in the terminal or airplane already.  My question is, why do airports and airline companies do this?  Have there been studies that show this method is superior to doing it by row?  My assumption would be filling the plane from the back to front would be the best method. This way there is no delay for passengers to be seated quickly.  Everyone in the back is putting their bags away which doesn't hinder others from getting to their seat, since people getting on would always be farther forward then those who have already boarded. And it would prevent people from clumping around the terminal door.