I have an OpenLayers map with a Google base layer and an OpenLayers vector layer on which people can draw their own bounding boxes using the DrawFeature control.  I have found that, as you zoom in, the vector is not plotted covering the same co-ordinates at each zoom level. Rather it seems to zoom at a different ratio to the underlying layer.  Strangely, if I resize the browser window, the vector then stays at a consistent position through all the zoom levels (i.e. becoming larger or smaller but covering the same geographic range, as one would want it to), but slightly offset from the position it was initially drawn at. The remains the case even if I make the browser window full size again.  See example below:   I draw a vector touching the Belgian border.  I zoom out and the vector is now well within Germany.      I resize the browser window and the box anchors to a consistent set of co-ordinates but offset from its initial position, now overlapping the Belgian border    Please note that this is not the same issue as the vectors scrolling more slowly than the map when dragging the map. The vectors seem to stick to the same area when dragged, but zooming causes them to move relative to the underlying Google layer.  Is this a known issue and can anyone help resolve?  In answer to the question about my initialisation of the layers, my code is as follows:  var miny=-2000000; var minx=6000000; var maxy=600000; var maxx=10003750;      // allow testing of specific renderers via "?renderer=Canvas", etc var renderer = OpenLayers.Util.getParameters(window.location.href).renderer; renderer = (renderer) ? [renderer] : OpenLayers.Layer.Vector.prototype.renderers;    //define the layers needed     g_phys  =   new OpenLayers.Layer.Google("Google Physical",{type: google.maps.MapTypeId.TERRAIN, numZoomLevels:20}, {isBaseLayer:true});     g_sat   =   new OpenLayers.Layer.Google("Google Satellite",{type: google.maps.MapTypeId.SATELLITE, numZoomLevels:20},{isBaseLayer:true});     bboxes  =   new OpenLayers.Layer.Vector("Bounding Boxes", {rederers:renderer});    //delete feature on select bboxes.events.on({"featureselected":function(e){bboxes.removeFeatures(e.feature); erasefeature(e);}}); //refresh on visibility change bboxes.events.on({"visibilitychanged":refreshMap}); //do stuff on modification of vector bboxes.events.on({"afterfeaturemodified":modbox});   //create new set of option for the map var options = {             projection: new OpenLayers.Projection("EPSG:3857"),             units: "m",             maxResolution: "auto",             maxExtent: new OpenLayers.Bounds(miny, minx, maxy, maxx),             theme: null,             layers: [                 //define the base layers for the map                 g_phys,                 g_sat,                 bboxes                      ]          };   //create new map object based on "map" div map=new OpenLayers.Map('map',options);

I want to overlay some data whose projection is WGS-84 on Google map layer in OpenLayers. But I just can't make them in the right place. I did as follows:  map = new OpenLayers.Map('map', {                    numZoomLevels: 20,         projection: new OpenLayers.Projection("EPSG:900913"),         displayProjection: new OpenLayers.Projection("EPSG: 4326")         }); googlelayer = new OpenLayers.Layer.Google("Google street", {sphericalMercator: true}); map.addLayer(googlelayer); veclayer = new OpenLayers.Layer.Vector("vector", {                                     projection: map.displayProjection                                     }; var geojson_format = new OpenLayers.Format.GeoJSON(); veclayer.addFeatures(geojson_format.read(jsonData));   Though I have assigned veclayer in 4326 projection, but it is still interpreted as 900913, and the display coordination system is also 900913, though I set displayProjection to 4326. What mistake do I make?


Generator(g) of multiplicative group (Zp where p is primary) is   an element the power of which by modulo(g^i mod p) can produce all   the elements of this group.   I have just tested this definition via python code and have not got the expected results. For example, lets take   p=11, so  Z* = {1,2,3,4,5,6,7,8,9,10}  I found only 4 elements, powers of which are actually generates all the memebers: {8, 2, 6, 7}. That is what I got (for 1<=i<=p, but i tested i up to 10^10):  1^i  :{1} 2^i  :{1, 2, 3, 4, 5, 6, 7, 8, 9, 10} 3^i  :{1, 3, 4, 5, 9} 4^i  :{1, 3, 4, 5, 9} 5^i  :{1, 3, 4, 5, 9} 6^i  :{1, 2, 3, 4, 5, 6, 7, 8, 9, 10} 7^i  :{1, 2, 3, 4, 5, 6, 7, 8, 9, 10} 8^i  :{1, 2, 3, 4, 5, 6, 7, 8, 9, 10} 9^i  :{1, 3, 4, 5, 9} 10^i :{1, 10}   Does this mean nothing but 2,6,7,8 are generators? Could you explain what is it I misunderstood?

I have this question, since I'm confused about this concept. Let's say I have a cyclic group, for example $\mathbb{Z}_7^{\times} = \left\{1, 2, 3, 4, 5, 6\right\}$. What is the relationship between the amount of generators for this group and $\phi(7)$, with $\phi$ Euler's function?   I found the generators as $\left\{3, 4, 5, 6 \right\}$. I know that if $G$ is a cyclic group of order $n$, and $g$ is a generator, then $g^s$ will also be a generator if and only if $gcd(s,n) = 1$. But then I read somewhere that if $n$ is prime (which in our case it is), then $\phi(7) = 6$ and the amount of generators should be $6$? This cannot be true for the group $\mathbb{Z}_7^{\times}$, since $1$ cannot possibly be a generator for multiplication.  For example, if I have the cyclic group $\mathbb{Z}_{13}^{\times}$, what is the best method to find a generator, and to find how many there are?


I switched to Michael, then Franklin, and then Trevor and there are no missions for anyone apart from a blue "B". I went there as Michael and I couldn't activate the mission. Can someone please tell me what I'm meant to do?

Trevor mentioned doing some flight training before starting the heist, which I did, but I haven't received word from Trevor about starting the mission. I read online that Michael's flight training and Franklin's shooting range training are optional, but I still have no indication on how to start the heist on my map. (The only marked missions are Lester's, which I'm leaving for later.) Is this bugged?


I'm trying to install a package (android-studio) through ppa, and am having some troubles. I'm 95% sure it is related to the corporate proxy we're behind of.  These are my settings:  env | grep -i proxy http_proxy=http://1.2.3.4:5678/ ftp_proxy=http://1.2.3.4:5678/ socks_proxy=socks://1.2.3.4:5678/ https_proxy=http://1.2.3.4:5678/  set | grep -i proxy ftp_proxy=http://1.2.3.4:5678/ http_proxy=http://1.2.3.4:5678/ https_proxy=http://1.2.3.4:5678/ socks_proxy=socks://1.2.3.4:5678/       -p --http-proxy --no-http-proxy\       -p --http-proxy --no-http-proxy\       -p --http-proxy --no-http-proxy\       -p --http-proxy --no-http-proxy\       -p --http-proxy --no-http-proxy\       -p --http-proxy --no-http-proxy\       -p --http-proxy --no-http-proxy\   Then, when I execute the command, the process gets stuck while trying to download the package from terminal.  sudo apt-get install android-studio Leyendo lista de paquetes... Hecho Creando árbol de dependencias        Leyendo la información de estado... Hecho Paquetes sugeridos:   default-jdk Se instalarán los siguientes paquetes NUEVOS:   android-studio 0 actualizados, 1 se instalarán, 0 para eliminar y 2 no actualizados. 4 no instalados del todo o eliminados. Se necesita descargar 0 B/36,2 kB de archivos. Se utilizarán 98,3 kB de espacio de disco adicional después de esta operación. (Leyendo la base de datos ... 885309 ficheros o directorios instalados actualmente.) Preparando para desempaquetar .../android-studio_162.3934792~trusty_amd64.deb ... --2017-05-18 10:37:30--  https://dl.google.com/dl/android/studio/ide-zips/2.3.2.0/android-studio-ide-162.3934792-linux.zip Resolviendo dl.google.com (dl.google.com)... 216.58.202.206, 2800:3f0:4001:815::200e Conectando con dl.google.com (dl.google.com)[216.58.202.206]:443...    PS: I can download the file through browser, and using wget from terminal  Does any1 know how I could solve this, even if I have to use a temporal setting or command?  Thanks

I am using Ubuntu 16.04 Beta 2 at the moment and every time I try to update at home via sudo apt-get update or upgrade trough sudo apt-get upgrade I wont get any feedback. Even installing of anything will have the same result. It will just "hang up" on 0% while fetching data.  $ sudo apt-get update [sudo] password for niclas:  0% [Connecting to archive.ubuntu.com (2001:67c:1560:8001::11)] [Connecting to archive.canonical.com (2001:67c:1360:8c01::1b)]   I have no idea how to solve the problem. I already tried to ping6 archive.ubuntu.com with 100% packet loss while just ping wont have any loss.  I changed the DNS-Server (IPv4 & IPv6) to Google's one no solution either.


Cameras can show a graph divided by 3 vertical lines. What does this graph describe about the picture, and how can I learn how to read it?

I realize that an image histogram is a graphical display of an images tonal distribution (i.e. horizontal darks to lights, vertical pixel distribution), but how does one really use it and why? I mean, can't you determine everything you need just by looking at the image?


I have a Mysql database having data below:  Thermometer -10℃ - 110℃  I copied that degree symbol from other website.  I did declare on my html like some example here:  <meta http-equiv="Content-Type" content="text/html;charset=utf-8" />   But it just wont show up when I call this data using php to my website, it only display  Thermometer -10?C - 110?C   What else do I need to do??

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


Let $a$, $b$, $c$ be integers. Show that if $a$ and $b$ are coprime   and $a$ and $c$ are coprime then $a$ and $bc$ are coprime.   My approach:  Suppose that $a$ and $b$ are coprime, $a$ and $c$ are coprime but $a$ and $bc$ are not coprime. This implies $gcd(a,b)=1$, $gcd(a,c)=1$ and that $\exists$ $d$ $\in$ $\Bbb N$ such that $gcd(a,bc)=d$ where $d>1$. Since $d>1$ then $\exists$ $p$ a prime number such that $p|d$.  We know that $p|d$ and $d|a$, this implies $p|a$. Also, $p|d$ and $d|bc$, this implies $p|bc$. By Euclid's lemma, we have two cases:  Case 1: $p|a$ and $p|b$, this implies $gcd(a,b)\ge p$. Since $p\ne1$, we have contradiction.  Case 2: $p|a$ and $p|c$, this implies $gcd(a,c)\ge p$. Since $p\ne1$, we have contradiction.  Since these cases are collectively exhaustive, then we have contradiction and $a$ and $bc$ must be coprime.  Is this approach sound? Is there an easier way?

How do I go about proving this?  If $\gcd(a,b)=1$ and $\gcd(a,c)=1$, then $\gcd(a,bc)=1$. I'm very confused with gcd proofs.


Let $f_{1}(x),f_{2}(x),\dots,f_{n}(x)$ be $n$ bounded and uniformly continuous functions on $\mathbb{R}$. Prove that their product $f_1(x)f_2(x)\cdots f_n(x)$ is also a uniformly continuous function on $\mathbb{R}$  My approach is to use mathematical induction. At the last step, I need to prove that the product of two uniformly continuos functions (which are the product of the first $n-1$ uniformly continuous functions by inductive hypothesis and the $n^{\text{th}}$ function), which doesn't require me to use the fact the functions are bounded.   So, I sense that this approach is not correct (but I'm not sure why) as I didn't use the fact that the functions are bounded. If it's really wrong, how do I make use of the fact that the functions are bounded? Thank you :)

prove that if two real valued  functions are uniformly continuous on some interval $I$  and each is bounded on $I$ then their product $f\cdot g=f(x)\cdot g(x)$ is also uniformly continuous on $I$ . Is boundedness of each function  on $I$ is  necessary for the product


I know that a double-periodic function is a function $f$ such that $f(z)=f(z+2\pi)$ and $f(z)=f(z+2\pi i)$. My idea is to use Louisville's Theorem which states that if $f$ is entire and bounded in the $\mathbb{C}$-plane, then $f$ is constant throughout the $\mathbb{C}$-plane. Since $f$ is entire, I know that I only have to show that $f$ is bounded. But does it simply follow that $f$ is periodic means $f$ is bounded?

Let $f: \Bbb C \to \Bbb C$ be an entire (analytic on the whole plane) function such that exists $\omega_1,\omega_2 \in \mathbb{S}^1$, linearly independent over $\Bbb R$ such that: $$f(z+\omega_1)=f(z)=f(z+\omega_2), \quad \forall\,z\in \Bbb C.$$Prove that $f$ is constant.   The intuition seems clear to me, we have the three vertices of a triangle given by $0$, $\omega_1$ and $\omega_2$. All points in the plane are one of the vertices of that triangle under a suitable parallel translation. The constant value will be $f(0)$, fine. Throwing values for $z$ there, I have found that $$f(n\omega_1) = f(\omega_1) = f(0)=f(\omega_2) = f(n\omega_2), \quad \forall\, n \in \Bbb Z.$$  I don't know how to improve the above for, say, rationals (at least). Some another ideas would be:   Checking that $f' \equiv 0$. I don't have a clue of how to do that. Write $w = a\omega_1+b\omega_2$, with $a,b \in \Bbb R$, do stuff and conclude that $f(w) = f(0)$. This approach doesn't seem good, because I only have a weak result with integers above. Finding that $f$ coincides with $f(0)$ on a set with an accumulation point. This seems also bad: the set on with $f$ coincides with $f(0)$ by which I found above is discrete.    Nothing works and this is getting annoying... And I don't see how analyticity comes in there. I'll be very thankful if someone can give me an idea.  (On a side note.. I know that this title is not informative at all. Feel free to edit if you come up with something better.)


I am making a topdown isometric real time game using Monogame.   I know how to get the mouse position for my camera view. How do I get the mouse coordinates relative to the entire scene?    My game's rendering looks isometric, but it's actually simply 2D and the illusion of isometric projection is done with a simple script that converts the cartesian coordinates for the mouse position to isometric ones, which I pass into a simple grid pathfinding algorithm that makes paths from them. This worked well for me when I used Game Maker.

I'm creating a game in XNA similar to Minecraft - Minecraft 2D  It looks like this    Here's how it works:   All blocks are generated once with fixed x,y coordinates and just re-drawn.      //generate world     for (int i = 0; i < 25; i++)     {         blocks.Add(new Block("top", i * 32, 32 * 7, Color.White));         for (int j = 8; j < 20; j++)         {             blocks.Add(new Block("dirt", i * 32, 32 * j, Color.White));         }     }  When user clicks on a block, I just browse through all blocks and check whether block exists.  if ((mouseCoordinate.X - (mouseCoordinate.X % 32)) == block.x && (mouseCoordinate.Y - (mouseCoordinate.Y % 32)) == block.y) {       //destroy block }  Currently, without any camera movements, everything works. When I move my camera just about 32px to the right, for example, it's all broken. I can't do previous step anymore.  What I need: I need to get mouse position relative to the map, not to the game window. How can I get mouse position relative to the map? Basically, I want mouse position 0,0 on the point I have circled here     How do I calculate it?  EDIT: here's my camera class (yes, Matrix)  using System; using System.Collections.Generic; using System.Linq; using System.Text; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.GamerServices; using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Input; using System.Reflection; namespace MojePrvniHra {     public class Camera2d     {     protected float _zoom; // Camera Zoom     public Matrix _transform; // Matrix Transform     public Vector2 _pos; // Camera Position     protected float _rotation; // Camera Rotation      public Camera2d()     {         _zoom = 1.0f;         _rotation = 0.0f;         _pos = Vector2.Zero;     }// Sets and gets zoom     public float Zoom     {         get { return _zoom; }         set { _zoom = value; if (_zoom < 0.1f) _zoom = 0.1f; } // Negative zoom will flip image     }      public float Rotation     {         get { return _rotation; }         set { _rotation = value; }     }      // Auxiliary function to move the camera     public void Move(Vector2 amount)     {         _pos += amount;     }     // Get set position     public Vector2 Pos     {         get { return _pos; }         set { _pos = value; }     }      public Matrix get_transformation(GraphicsDevice graphicsDevice)     {         _transform =           Matrix.CreateTranslation(new Vector3(-_pos.X, -_pos.Y, 0)) *                      Matrix.CreateRotationZ(_rotation) *                      Matrix.CreateScale(new Vector3(Zoom, Zoom, 1)) *                      Matrix.CreateTranslation(new Vector3(graphicsDevice.Viewport.Width * 0.5f, graphicsDevice.Viewport.Height * 0.5f, 0));         return _transform;     }      } }   and here's how I start my spriteBatch         spriteBatch.Begin(SpriteSortMode.BackToFront,                 BlendState.AlphaBlend,                 null,                 null,                 null,                 null,                 cam.get_transformation(graphics.GraphicsDevice));


I was working on tf.matmul op with multidimensional input arguments. For example given in code below,  import tensorflow as tf import numpy as np  nn_arch = [100,1200] batch_size = 128  n_ = np.random.normal(size=[batch_size,nn_arch[1],nn_arch[0]]) w_ = np.random.normal(size=[nn_arch[1],nn_arch[0]]) x_ = np.random.normal(size=[batch_size,nn_arch[0],1])  n = tf.constant(n_) w = tf.constant(w_) x = tf.constant(x_) nw = n + w c = tf.matmul(nw,x) sess = tf.InteractiveSession()  c_ = np.zeros(shape=[batch_size,nn_arch[1],1]) for i in range(batch_size):     c_[i,:] = (n_[i,:,:] + w_).dot(x_[i,:,:])  print(sess.run(c)-c_) print(np.max(np.abs(sess.run(c)-c_)))   This function will print the last line with value of the order of 1e-15. Why is there a this small amount of difference between two ops, that are basically doing same calculations at same precision float64?

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


I just did a fresh install of Ubuntu 16.04 on a desktop computer. During the installer, the auto network script failed so I configured it manually (entered my own IP, entered in the subnet mast, entered in the default gateway) and everything was okay with no problems. It connected successfully and finished the install.  Now that it's installed, I'm not getting any network connectivity - I can't even ping the gateway. I'm using wifi and am unable to use ethernet. ifup/ifdown on enp2s0 doesn't have an issue. I tried with DHCP, but DHCP just hanged and didn't solve it either. I also verified the requested IP address wasn't in use on the network.  root@ubuntu:/home/liam#  lshw —class network  *—network      description: Ethernet interface      product: RTL8111/8168/8411 PCI Express Gigabit Ethernet      vendor: Realtek Semiconductor Co., Ltd.      physical id: O      bus info:  pci@0000:02:00.0     logical name: enp2s0      version: 06      serial: b8:97:5a:32:c1:5f     size: 10Mbit/s      capacity: 1Gbit/s      width: 64 bits      clock: 33MHz      capabilities: pm msi pciexpress msix vpd bus_master cap_list      configuration: autonegotiation=on broadcast=yes driver:r8169      resources: irq:25 ioport:d000(size=256) memory:f0004000-f000  *-network DISABLED      description: Wireless interface      physical id: 1      bus info: usb@1:2     logical name: wlxec086b1eaf1b      serial: ec:O8:6b:1e:af:1b      capabilities: ethernet physical wireless      configuration: broadcast=yes driver:r8188eu multicast=yes     Output of /etc/network/interfaces  # This file describes the network interfaces available on your system # and how to activate them. For more information, see interfaces(5).  source /etc/network/interfaces.d/*  # The loopback network interface  auto lo  iface lo inet loopback   # The primary network interface  auto enp2s0 iface enp2s0 inet static          address 192.168.1.200         netmask 255.255.255.0          network 192.168.1.0          broadcast 192.168.1.255          gateway 192.168.1.254          # dns-* options are implemented by the resolvconf package         dns-nameservers 192.168.1.254          wpa-ssid ATT548CA          wpa-psk frank777  #auto enp2s0 #iface enp2s0 inet dhcp  #       wpa-ssid ATT548CA #       wpa-psk frank777    EDIT: Wireless Info Script results:

Connecting to the wireless is relatively simple.  After some struggle, you have wifi in your installer. You can install Ubuntu Server and everything is alright. You are ready to boot your new system.    After setup finished, wifi settings disappeared.  tl;dr: How do I connect to a wireless (WPA2 Personal) network from Ubuntu Server 12.10?    What I have tried so far:  Connected with iw* commands. Obtained IP address with dhclient. Put these commands to etc/rc.local.  On boot, the server waits 120 seconds with message "Waiting for network to come up"  To fix this, I removed everything /etc/network/interfaces (wpa-psk and wpa-ssid). This did not work. It was still waiting. I found an answer, which said I could just remove the /etc/... (the file that was in charge of the 120 second wait time.)    I did that, and kept a backup of it. Now the server waits ~3 seconds (modified sleep within the file) and boots up. However, there's no network connection available. It's some dhcp error.  As I was out of options, I tried using the one in comment. The one that used "tee". Turns out it does not work either.    How can this whole thing be so inconsistent? How can they not install the firmwares on the ISO while it would perfectly fit (673+~10MB = 683). How can the installer NOT copy the necessary files and set up the connection to be used later? (Or ask if the user wants to use it.)


My father and I have the same IP address on my network. (I found this on cmyip.com) This makes it impossible for me to host servers (for instance minecraft or terraria) and I don't know the solution. Everyone I've asked so far says "Set a manual IP" but nothing I've found shows me how.  Anyone got any help? I kind of desperate after a year and a half of this...

My PC is behind a NAT router that has a public IP address. If I want to host a website then I believe I need a domain name which I can purchase from some site which would pledge to resolve all DNS requests for that domain name and send the IP address of my NAT router (assuming I do not want to host my domain name on their servers). Now I want to host a web server on my computer.   What changes should be done to the NAT router's configuration to forward all HTTP requests for example.com to my PC in the internal network. Is the above strategy correct? Is it commonly used?


I am not a native speaker, but I noticed that sometimes people use Bachelor or Bachelor's in some context, although I don't understand the difference:  See for instance also this question   For instance I would call myself a Bachelor student, but do I do my Bachelor's studies or my Bachelor studies?   Actually, I don't understand the difference between Bachelor and Bachelor's and I don't know when to use one or the other. Could anybody help me with that?

The question asks it all really. When referring to a master's degree, do you use an apostrophe or not? That is, is it "a master's" or "a masters"?


I just booted 1st time into Ubuntu Server 14.04.1 LTS (no GUI), enabled UFW, went to update with sudo apt-get update and the results showed this:  Ign cdrom://Ubuntu-Server 14.04.1 LTS _Trusty Tahr_ - Release amd64    (20140722.3) Trusty InRelease Ign cdrom://Ubuntu-Server 14.04.1 LTS _Trusty Tahr_ - Release amd64 (20140722.3) Trusty/main Translation-en_CA Ign cdrom://Ubuntu-Server 14.04.1 LTS _Trusty Tahr_ - Release amd64 (20140722.3) Trusty/main Translation-en Ign cdrom://Ubuntu-Server 14.04.1 LTS _Trusty Tahr_ - Release amd64 (20140722.3) Trusty/restricted Translation-en_CA Ign cdrom://Ubuntu-Server 14.04.1 LTS _Trusty Tahr_ - Release amd64 (20140722.3) Trusty/restricted Translation-en Reading package lists... Done   This is not what I expected to see. In my current desktop environment there is a long list that scrolls past in the terminal.  I assume that there are no repositories listed in the /etc/apt/source.list (haven't figured out how to read contents of that file yet)  What should I do?

There are now errors when updating and I cannot install most software due to a corrupted  /etc/apt/sources.list   file. Is there a copy I can download to replace it?  The file would be for Ubuntu 12.04 (Final Beta) in the United States.


I have a table that I want to insert on a page, but at least one (perhaps both) of the following conditions are met:   The table is too wide to fit within the text block or page. That is, I'm exceeding some horizontal restriction. The table is too tall to fit within the text block or page. That is, I'm exceeding some vertical restriction.   What are my options to make this table fit? If it doesn't fit, regardless of my attempts, what other options exist?


Recently, I was planning to install Opera browser on my system, so I visited the official website, and downloaded the .deb file, and installed it. However, to my concern, for every update, I will be needing to download the .deb file again and again, since I have not updated the repository in Software & Updates section. At this point I thought, Chrome itself added the repository, so maybe Opera must have done it too, but it didn't. Same issue with the Discord application, i.e., I have to visit the official website and download the .deb file for timely-updates. However, I found that the Ubuntu software market ships both, Opera and Discord, but as snap packages. So I thought to give it a try, since it would relief me of downloading the .deb files from the official website, and I can update them with just a command. Here, I was recommended by some friends of mine that I shouldn't opt for the snap, because of some errors or something, which I am currently completely unaware of, and instead go for the official .deb files. Can someone explain me the differences? EDIT: Since past few months, Chromium has too moved itself to the snap packages. Does this have any difference from past when it was in apt-get package system?

This is not a duplicate of the following questions     because:  My question specifically states that I am interested in end-user experience, not ease or efficiency of development, which is what the other question largely refers to.  As has been noted, development/deployment affects end-user experience, but it is not all there is to it, and neither of the referenced questions address issues that directly impact an end-user's ability to use the application (e.g. trouble accessing data on other partitions, sluggishness, etc.) Maybe "compelling" wasn't the right word to use; my intent was to ask about real-world, experiential consequences, i.e., things that happen or  don't happen, as opposed to theoretical/architectural statements that, while presumably accurate, don't appear to be backed up with any real-world examples to support the statement. I should have stated more directly that my intention was to get answers that consider the balance of "advantages" to snaps against the real-world downsides experienced by end-users. The "duplicate" question is largely theoretical, and doesn't discuss end-user experience at all. The "duplicate" question makes no mention of anything remotely similar to the example I used here, i.e., that there is an end-user downside to snaps (in this case, lack of access to data on other partitions and snap app performance) that isn't discussed in any available documentation that I can find.   While I understand that snap has a big advantage in making apps more widely available, is there any compelling reason to choose snap over apt, if the app is available for my distro/version via an apt package? I am curious because I've been doing some reading about snaps, and all the excitement about the method seems to be about things that are advantageous for app developers, but I've seen virtually nothing on how this makes life easier for end users (aside from the obvious; that they may be able to install apps that aren't otherwise available on their distro/version). I installed snapd and installed a couple of snaps and was really frustrated and disappointed.  The snap apps are slow and it's difficult, if not impossible, to access files on other partitions from within the snap. While I've seen plenty of info that says snaps are "faster," "easier," "safer," etc., I haven't been able to find anything that explains why or how this is actually the case. Being very new to Linux, I am wondering if maybe I'm just missing something obvious? To be clear, I understand why the technology might be useful overall, but I can't find anything that explains whether/why it is a better option even when the app in question is available for install via a more traditional method, and all dependencies are met.


I have a table that looks like this. let's call it table1:  |attributeMask | |--------------| | ,300,302,400 |  | ,301,500     |  | ,900,876     |    These are varchar values.  Then I have another table2:   columnNumber  |  |------| | 300  |  | 500  |  | 900  |    These ones are int.  What I need is a query to compare columnNumber with values inside attributeMask.  For example, I need to find inside attributeMask, rows that has 300 (for each row. the second columnNumber is 500, and I will compare this 500 with the respective row from it's own attributeMask that can be ,299,34,500). I'm trying to use FOR XML PATH or other functions but I have no idea what to do.  This is the entire query that i could create until now:  select  top 3       t1.[Name]    ,t1.ColumnNumber    ,t3.AttributeMask     ,t3.changeData     ,t3.CreatedOn    ,t3.ObjectTypeCode    ,t3.UserId from metadataschema.attribute     t1 inner join  metadataschema.Entity t2     on t1.EntityId=t2.EntityId inner join AuditBase              t3     on t2.ObjectTypeCode=t3.ObjectTypeCode where t2.ObjectTypeCode=1  //this is wrong. but is this part that I need to fix and convert(varchar,t1.ColumnNumber) in (select t3.AttributeMask from  AuditBase) //until here and t3.CreatedOn BETWEEN '20190902' AND '20190913'  and t1.[Name] in ( 'address1_postalcode','smart_caixapostal','smart_tipologradouro','smart_complementoprincipal','smart_estado','smart_logradouroprincipal','smart_bairroprincipal', 'new_regiao','smart_numero','address1_city','smart_pais','smart_validarendereco','smart_cepcobranca','smart_caixacobranca','smart_validarendereco_cob', 'smart_tipologradourocobranca','smart_logradourocobranca','smart_numerocobranca','smart_complementocobranca','smart_bairrocobranca','smart_municipiocobranca', 'smart_estadocobranca','territoryid','smart_paiscobranca','smart_cepmkt','smart_logradouromkt','smart_complementomkt','smart_ufmkt','smart_tipodelogradouromkt', 'smart_bairromkt','smart_ddidddmkt','smart_caixapostalmkt','smart_numeromkt','smart_municipiomkt','smart_telefonemkt' )

I'm currently trying to create a View from a Table that does the following:  Table A ╔═════════════╦═══════════════╗  ║ PART NUMBER ║   FILE NAME   ║ ╠═════════════╬═══════════════╣ ║  PN0001-01  ║      FOO      ║ ║  PN0002-01  ║      BAR      ║ ║  PN0003-01  ║    FOO,BAR    ║ ║  PN0004-01  ║  BAR,FOO,FOB  ║ ╚═════════════╩═══════════════╝   To create  View B ╔═════════════╦═══════════════╗  ║ PART NUMBER ║   FILE NAME   ║ ╠═════════════╬═══════════════╣ ║  PN0001-01  ║      FOO      ║ ║  PN0002-01  ║      BAR      ║ ║  PN0003-01  ║      FOO      ║ ║  PN0003-01  ║      BAR      ║ ║  PN0004-01  ║      BAR      ║ ║  PN0004-01  ║      FOO      ║ ║  PN0004-01  ║      FOB      ║ ╚═════════════╩═══════════════╝   So, essentially, I need to take records from Table A and insert them into View B, where if the record from A has a LIKE '[,]' property, then that field is split into multiple records in B, depending on the number of times the ',' is present, with the text between each ',' being given its own record in View B.


Prove that:- Any group of order 4 is either cyclic or isomorphic to Z2*Z2 where Z2 is residue group of natural numbers modulo 2.

I want to prove at any group of order $4$ is isomorphic to either $\Bbb Z_4$ or $\Bbb Z^*_8$. I know that these two groups are not isomorphic to each other because they have different order, but I cannot go further to prove at any group of order 4 should be isomorphic to either of them. Help would be greatly appreciated.  Thanks!


As far as I know, it is necessary to multiply the focal length by the crop factor. My Sony Nex 5 has a crop factor = 1.5 For lens Helios 77M-4 1.8/50 focal length will 50 * 1.5 = 75  Is this true for Sony Nex?  And also for M39 lenses?

My friend has a Tamron 24mm lens on his Nikon D5000 and he says that because of its age and the fact it is manual focus, it is still actually a 24mm on his crop sensored camera. Is this right? If so, which 50mm lenses would still be 50mm on the Nikon d5100?


Sorry for the silly question... :)  I found this statement in a query:  select * from table a, table b WHERE a.id =b.id(+)   What does the plus between brackets mean?  Thank you

Found the following in an Oracle-based application that we're migrating (generalized):  SELECT     Table1.Category1,     Table1.Category2,     count(*) as Total,     count(Tab2.Stat) AS Stat FROM Table1, Table2 WHERE (Table1.PrimaryKey = Table2.ForeignKey(+)) GROUP BY Table1.Category1, Table1.Category2   What does (+) do in a WHERE clause? I've never seen it used like that before.


I did install Ubuntu 13.10 on my old PC. Everything went fine except for when I login into my account there is no menubar, no icon bar, just only my wallpaper. I can do thing like creating a new folder and even access settings (so I did setup my internet connection) and I can acces the log thingy (forget how to call it) by pressing ctrl+alt+F1, but I can't do anything else with it. I had this same issue also when I did try to Install Ubuntu in the past (that was version 12.Idontknowanymore). I did spend this whole evening searing how to fix this on the internet, but without any succes.  My computer isn't really super, I think it has about 1GB RAM, and the original OS is Windows XP (I did pick the 32Bit version of Ubuntu).  Does anyone knows how I can fix this problem and start using Ubuntu? Thanks  Sincerely, Ingo

When I login, nothing happens.   I am presented with my desktop wallpaper.    No Dash, no Launcher, nothing.


1950's (?) black and white movie, husband and wife scientists have radio in their home picking up transmissions possibly from Mars. Their kid says "How about Pi?" (the number) while eating a piece of pie, suggesting that the number Pi be used as a code to check if the signals are intelligent by testing if they recognize the sequence of digits and continue it.  Movie had political overtones.

I am looking for the title of a 1950s science fiction movie, involving an astronomer trying to decode some extraterrestrial signal, where the juvenile (male) character asks 'how about pi?' which all the adults interpret as a foolish 'how about pie?' question.


Regarding the firestorm that was Monica's firing, mods resigning, SE non-apologizing, then backpedaling, then apologizing, then putting out the wildly negatively received FAQ on the new CoC regarding pronouns, it's been pretty hard to follow, hard to understand, and frustrating to hear about.  What hasn't been hard to follow and identify, however, is the both explicit and subtle instances of homophobia, queerphobia, and transphobia that have emerged.  I suppose, since most everyone is frustrated with the new pronoun CoC, LGBT-phobes have decided they can blend their bigotry in with the general and appropriate outrage that isn't directed at the LGBT+ users on SE, but rather SE's mishandling of an important issue.  As a queer woman, seeing comments with lots of upvotes criticizing queer and trans users and blaming this mess on them, lamenting political correctness that requires you refer to someone how they'd like you to, and anger at the fact that SE sort of, maybe, at the very beginning, wanted to protect LGBT users, is very troubling and uncomfortable for me to see.  I feel, right now, with all of this in mind, like I can't be open about my identity on SE.  To my fellow LGBT+ users, do you feel the same way?  If this is the case with others as well (and me hopefully not just being a snowflake), how can we fix this?  Most importantly, can we fix this?   (My question is, is this issue fixable, not, is it an issue.)

I am a member of the network and posting anonymously for my safety.  CW: References to and examples of hate speech  I don't want to put blame anywhere, but unfortunately due to the huge turmoil created by the recent CoC changes, several right-wing websites have started reporting and thus directed attention of far-right groups to this network. I don't want to provide any links, but it's not too difficult to find examples with your favorite web search engine.  Now, while you have the typical gut wrenching hate speech with murder and torture fantasies, there was one particular case where someone posted pseudo-code for automatically going through the member database of SE and finding users who have listed their pronouns in their "about me" section. The pseudo-code then moved those users into a category for torture and extermination. While at this point it's pseudo-code I fear it's not too unlikely to think that someone could put this into a working tool for doxxing LGBTQ users on this platform. It seems that the Neo-Nazis consider the downvotes on the CoC FAQ an affirmation of their views.  I therefore have removed my pronouns from my "about me" section. This is unfortunate. In the past I did feel welcome. The few situations in the past where someone misgendered me have all been resolved quickly and easily, with everyone being friendly, understanding and accepting when I corrected them.  Now I don't dare correct people any more, not because I fear backlash from the particular person in the particular situation, but because literal Neo-Nazis are now watching this platform with horrible intentions.  I have no idea how to fix this, but I guess we can only wait for things to settle down.


Both of the yellow spheres are exactly identical, but the one in the glass cube looks more bleached than the right one. Which variables should I be looking at to make the color of the left sphere look as vivid as the right one? Thank you all always!

Which factors should I look at to make the reflection as neat as that of the reference image? Some of the thigs I've tried:  Increasing roughness, but still have too many distorted reflections and also I can't see the yellow sphere in the cube clearly like the reference image.  Changing variables on Ray visibility, but nothing seemed to work. Material of the cube is set to default material with : Specular 0.5 / Roughness 0 / Transmission 1 level   Reference  My Cube  – Bottom and left sides has way too many distortions.


I am planning to upgrade my internet bandwidth from 150 Mbps to 350 Mbps in my office network. How do I confirm that this upgrade has been completed by service provider and I am getting 350 Mbps?

What is the simplest way to check my actual broadband connection speed?


I asked this before but I'm having problems still. I need to connect nine LEDs in parallel with a 9 volt battery. The wire leading away from the 9V separates into three and on each three are three LEDs in series. A calculator told me that if I have 2.25 volt, 28 mA LEDs on each branch I need an 82 ohm resistor. If I have an 82 ohm resistor and 9/82 is .10976... wouldn't my current be too low? I just don't know how to do it. How do I decide which resistor I need to use with an LED?

I'm trying to work out what value resistor to use in a LED circuit. The equation I'd use to do this is:  $$ R = \frac{V_{cc} - V_f}{I_f} $$  Seems logical, and makes complete sense. The answers to the question  confirm this too.  I have the following LEDs:   \$ V_f = 3.3V \$ \$ I_{f_{typ}} = 20mA \$   Using a 5V power supply:   \$ V_{cc} = 5V \$   Plugging these into the above equation gives:  $$ \begin{eqnarray} R & = & \frac{V_{cc} - V_f}{I_f} \\   & = & \frac{5V - 3.3V}{20mA} \\   & = & 85\Omega \end{eqnarray} $$  All good so far.  However, if I use the calculator at , that gives me 100Ω. If I use the ElectroDroid app on my phone, that gives me 85Ω.  So, I assume that the linear1 calculator is using a different method of calculating this resistor value; is there some better way of doing this?


What is the maximum number of images allowed per question?  I believe it's five links per question, but unsure about images.  If there's a good way to circumvent, that would be appreciated.    Sometimes it's not possible to grab text.  (for what it's worth, pushing the limit .)

There's one question in SO I'm planning to answer with a really long answer. While I'm still baking my post, these questions dawned to me:   What is the maximum character length of a post? How many links can I include, at most? How about the number of images? What is the character limit on the question title? Do the limits on questions apply to answers as well, or do they have different ceilings?


I use "natural scrolling" on my mouse, and in the last few days I've found that after unplugging my mouse and then plugging it back in, those settings are reverted. In order to return to using natural scrolling I must first turn off the setting (because the settings display shows it's still on) and then turn if back on again. Restarting the computer while the mouse is plugged in will also return scrolling to its intended setting. Any help regarding this is much appreciated.  Ubuntu 20.04.1 LTS GNOME version 3.36.3 Not really sure what other version info is relevant here.

After a recent kernel upgrade, I started noticing an annoying issue: the "Natural scroll direction" changes every time I change the keyboard/mouse set on my laptop (Dell Inspiron 15).  More specifically, I have one Logitech set at work and a different set (also Logitech) at home.  It seems as though every time I switch peripherals the scroll direction is changed.  I want the Natural Scrolling to be left by default and not arbitrarily switch to the 'regular' scrolling direction. I believe this may have started after the update to the 5.4.0-52 64-bit kernel (Ubuntu 20.04 LTS, GNOME version 3.36.3).  I should note that around the same time I purchased a new set of keyboard/mouse combination for home, though I did not notice the issue until the kernel update a few days later. What is worse, the toggle button in the Settings > Mouse & Touchpad > Mouse > Natural Scrolling is NOT changed but the scrolling direction changes.  That is, when I just change locations, the scrolling direction is 'regular' while the Natural Scrolling is turned on.  To fix this, all I have to do is to toggle the button twice and then it comes back to my preferred scrolling direction. Has anyone else experienced this issue?  If so, any way you suggest to fix it without having to change the direction every time I change peripherals.


I get a "An error occurred during voting" error message in a red popup when deleting a comment fails. But that message is misleading as I wasn't voting the comment but deleting it. It should be "An error occurred during deleting".  Steps to reproduce:   Post a comment, say, 'Blah blah bladdeddy blah!' Disconnect your device from the internet Press the delete button X next to the comment You get "An error occurred during voting" which is misleading

I had posted a comment on a question asking the OP to provide more information on the exact problem. Seeing that, the OP posted more information about the question and I decided to delete my comment as its purpose was achieved. But when I tried to delete the comment, I got an error message. This is the error message I got when I tried to delete that comment.    The problem is not with the comment not getting deleted. I could wait for a while and delete the comment later, but the problem is with the error message which is displayed when trying to delete the comment.     An error occured during voting   This error message for a comment deletion failure is certainly not the best.  So, can we please have a more relevant error message, something like     An error occured while deleting the comment   or anything better the devs could come up with, when we the deletion of a comment fails?


Similar to this question  which was intended for javascript, it has spawned off numerous  for various different languages. I'm curious if the following can ever evaluate to true in PHP:  ($a == 1 && $a == 2 && $a == 3)   To follow up a bit more, it seems  will yield the desired result (This was not the case for javascript, due to the way type casting works in both languages). A few answers (in javascript) worked with === as well, so in PHP with typechecking (===), can the following ever yield true?  ($a === 1 && $a === 2 && $a === 3)

What is the difference between == and ===?  How exactly does the loosely == comparison work? How exactly does the strict === comparison work?  What would be some useful examples?


I'm a Little confused about some numbers in C-Code. I have the following piece of Code  int k; float a = 0.04f;  for (k=0; k*a < 0.12; k++) {   * do something * }   in this case, what is the type of "0.12" ? double ? float ? it has never been declared anywhere. Anyways, in my program the Loop above is excuted 4 times, even though 3*0.04=0.12 < 0.12 is not true. Once I Exchange 0.12 with 0.12F (because I am globally restricted to float precision in all of the program), the Loop is now executed 3 times. I do not understand why, and what is happening here. Are there any proper Guidelines on how to write such statements to not get unexpected issues?  Another related issue is the following: in the Definition of variables, say  float b = 1/180 * 3.14159265359;   what exactly "is" "1" in this case ? and "180" ? Integers ? Are they converted to float numbers ? Is it okay to write it like that ? Or should it be "1.0f/180.0f*3.14159265359f;"   Last part of the question,  if i have a fuction   void testfunction(float a)   which does some things.  if I call the fuction with testfunction(40.0/6.0), how is that Division handled ? It seems that its calculated with double precision and then converted to a float. Why ?   That was a Long question, I hope someone can help me understand it.

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


As per my code:  using System.Collections; using System.Collections.Generic; using UnityEngine; using UnityEngine.UIElements; using Cursor = UnityEngine.Cursor;  public class FirstPersonController : MonoBehaviour {     public float speed = 5;     public float jumpPower = 4;      Rigidbody rb;     CapsuleCollider col;       private GameObject player;     private float minClamp = -45;     private float maxClamp = 45;     [HideInInspector]     public Vector2 rotation;     private Vector2 currentLookRot;     private Vector2 rotationV = new Vector2(0,0);     public float lookSensitivity = 2;     public float lookSmoothDamp = 0.1f;     public Camera cam;     public GameObject crossHair;     bool isActive;      // Start is called before the first frame update     void Start()     {         Cursor.visible = false;         Cursor.lockState = CursorLockMode.Locked;          rb = GetComponent<Rigidbody>();         col = GetComponent<CapsuleCollider>();         player = transform.gameObject;         crossHair = GameObject.FindWithTag("CrossHair");       }         // Update is called once per frame         void Update()     {         float Horizontal = Input.GetAxis("Horizontal") * speed;         float Vertical = Input.GetAxis("Vertical") * speed;         Horizontal *= Time.fixedDeltaTime;         Vertical *= Time.fixedDeltaTime;         transform.Translate(Horizontal, 0, Vertical);             if (isGrounded() && Input.GetButtonDown("Jump"))          {             rb.AddForce(Vector3.up * jumpPower, ForceMode.Impulse);         }          if (Input.GetKeyDown("escape"))         {             Cursor.lockState = CursorLockMode.None;         }          if (Input.GetButtonDown("Sprint"))         {             speed = 15;             //Debug.Log("Sprint Button Held Down");         }          if (Input.GetButtonUp("Sprint"))         {             speed = 5;             //Debug.Log("Sprint Button Let Go");         }          if (Input.GetKeyDown(KeyCode.H))         {             isActive = !isActive;         }          if (isActive)         {             crossHair.SetActive(true);         }         else         {             crossHair.SetActive(false);         }            rotation.y += Input.GetAxis("Mouse Y") * lookSensitivity;         rotation.y = Mathf.Clamp(rotation.y, minClamp, maxClamp);         player.transform.RotateAround(transform.position, Vector3.up, Input.GetAxis("Mouse X") * lookSensitivity);         currentLookRot.y = Mathf.SmoothDamp(currentLookRot.y, rotation.y, ref rotationV.y, lookSmoothDamp);         cam.transform.localEulerAngles = new Vector3(-currentLookRot.y, 0, 0);     }      private bool isGrounded()     {         return Physics.Raycast(transform.position, Vector3.down, col.bounds.extents.y + 0.1f);     }    }   I can't figure out what I am doing wrong in my code, I tried to write a first person controller from scratch.  The full project can be downloaded from:   My player goes through any wall or object easily despite it having colliders on the objects and a rigidbody and collider on the player.  I have gone through my code line by line and I cannot work out what is wrong? If someone could please advise me what to change or add to my code to fix this, or / and explain the concept, presumably physics related, as to why this is going wrong please?

I need help with a script for a very simple car that uses transform.Translate:  public class car1 : MonoBehaviour {      public PauseMenu pause;     [Space]     public Car_Script car_s;     public float speed;     public GameObject car;      void FixedUpdate()     {          if (car_s.InCar == true)         {             if(pause.isPaused == false)             {                 if (Input.GetKey(KeyCode.W))                 {                     car.transform.Translate(Vector3.forward * Time.deltaTime * speed);                      if (Input.GetKey(KeyCode.A))                     {                         if (speed <= 0)                         {                         }                         else                         {                             if (speed > 0F && speed <= 50F)                             {                                 car.transform.Rotate(Vector3.down, 2F);                             }                             else if (speed > 50F && speed < 90F)                             {                                 car.transform.Rotate(Vector3.down, 1.3F);                             }                             else if (speed > 90F)                             {                                 car.transform.Rotate(Vector3.down, 0.9F);                             }                          }                     }                     if (Input.GetKey(KeyCode.D))                     {                         if (speed <= 0)                         {                         }                         else                         {                             if (speed > 0F && speed <= 50F)                             {                                 car.transform.Rotate(Vector3.up, 2F);                             }                             else if (speed > 50F && speed < 90F)                             {                                 car.transform.Rotate(Vector3.up, 1.3F);                             }                             else if (speed > 90F)                             {                                 car.transform.Rotate(Vector3.up, 0.9F);                             }                          }                     }                 }             }         }     } }   Whenever I drive the car it immediately goes through walls.   I have colliders on everything. The car has mesh colliders set to convex.   I've searched around quite a bit for answers and it seems that a common one is using rigid bodies. But whenever I even put a rigid body on the car, it flies out into the sky.


I'm not sure if "the" before "long-term consequences of climate change" (and in similar cases of "the noun of noun") is necessary or optional. My instinct tells me I should use it, but I've seen so many people leave it out. I can't find any rules on this. Here's the full sentence:  Communication around climate change has so far focused on the long-term consequences of climate change.  Or could it be:  Communication around climate change has so far focused on long-term consequences of climate change.

Which of the following expressions is correct?:   The political implications of ... Political implications of ...   Is the The necessary here? When I search the web using Google, in most cases The is used. Here is an Ngram comparison of the two terms:    We can see from this that sentences starting with "The political implications of ... " are, according to these figures, over 10,000% more prevalent than sentences beginning with "Political implications of ... " in printed books available on Google. Why?


I need to drive several indicator LEDs at <2mA.  Each LED has a nominal Vf between 3.2V and 3.3V (Vf max up to 4V).  In the past I've had the luxury of (a) current-limiting resistors or (b) constant-current power supplies.    But what do I do when my entire circuit has to run off a single 3.3V SMPS, and the microprocessor outputs are limited to 25mA? Here solution A isn't applicable, and the budget doesn't allow solution B (unless maybe all the LEDs can share a single current-limited supply--they don't all have to be on at the same time--and yet I still get to control the LEDs from a microprocessor directly, without external transistors.)  Background:     I have a microprocessor with a few PWM outputs, but not enough for every LEDs.  (yes, multiplexing is possible) This is an ultra-low-power, portable application. BOM cost has to be low, low, low.

Modern electronics industry has developed very efficient LEDs with nice and fancy colors (“true green” , “cyan”, and “blue”) based in InGaN technology, or similar. Some of these LEDs are specified as having forward voltages of 3.2 to 4.2 V. Here are examples of such LEDs, , or surface-mount .  But the usual MCUs are powered from 3.3 V supply, and the GPIO output is usually at 3.1-3.2 V, which seems to be barely enough to drive these LEDs . How can I use these LEDs as indicators of some signal statuses, or power rail status? Do I need a series resistor R1 here?    If yes, how do I choose its value?  DISCLAIMER: This "question-answer" comes as elaboration of the original question , to address the particular use case of LEDs as logic state indicators.


In Star Trek : TNG, the android Data has a cat named Spot. Spot appears in several episodes in multiple seasons. Has this role always been played by the same cat? Or have there been other 'Spots'?

After seeing a question regarding the acquisition of Data's cat Spot, the point was brought up that Data's  midway through the series.  My question is, how? I have thought up two possibilities (see below to my own answer) but I'm wondering if there aren't possibly others that might fit better. Exhibit A- Spot the Younger  Exhibit B- Spot the Older


This has been modified so as to not duplicate.  Please remove that status or provide a link the the duplicate.  When one sees this "banned" icon in the system tray:    How does one determine which program's icon failed to load?  Hovering over it fails to do so.  Clicking on it drops down a blank area.

Affects:  14.04 / 14.10 / 15.04 / 15.10 / 16.04 / 16.10  I started my dropbox deamon today, with the following result in the panel:     The icon with the warning/failed symbol should be my Dropbox icon. I cannot right-click or left-click it, so no interaction.  I am running Xubuntu 15.10 on 4.2.0-27-generic x64. I also tried to re-install Dropbox, reinstall nautilus-dropbox, recursively delete ./cache/sessions/ as well as set other themes and icon sets.  Apparently nothing helped and similar problems described here and on other boards are similar, not the same and do not work in my case.


Some questions on Stack Overflow could be answered with a minimal amount of leg-work and research by the poster. The questions are either trivial, such as "How do I print a number as hex instead of decimal?" or are extensively covered by tutorials and articles both on Stack Overflow and the web at large ("How do I write a simple template in C++?"), or both.  As we all know,  on Stack Exchange. There are some very good reasons for that which are well-covered in the discussions here on Meta.  Many of these questions, despite being so easy that the poster should have found the answers with 5 seconds of searching, do have good answers here, and recurring questions can easily be marked as duplicates. This seems perfectly appropriate where possible. The more general questions ("How do I learn C?") can be closed as Too Broad.  But I feel like there is a gap between "Duplicate" and "Too Broad" that is not covered by any existing close reason. Sometimes the question is specific, extensively covered by outside material, and yet not covered on Stack Overflow. I really miss the old "" close reason, which partially covered this gap.  Now that it's gone, though, what should we do with questions like this? Questions where there's no exact match on SO, but where you can find an answer yourself in 5 seconds by searching Google?  If the question doesn't have an exact match, should we just answer it anyway -- in the spirit of "building a knowledge base" -- even if that basically means quoting stuff from reference material that could be found in 5 seconds of Googling? Or is there perhaps room for a new close reason to cover this kind of thing? How much hand-holding do we want Stack Overflow's body of work to do?

How should you respond to "Give me a fish" / RTFM questions? I mean the case where people post questions simply to get someone else to write their code for them, on topics that would usually be the first result on Google if they had taken the effort to search once before posting.   Usually I just plug in a link that points them to the right place... and the Google search terms I used if I'm annoyed (aka I do their Google search for them). This is the "teach them to fish" approach. But given the big and growing SE user-base, these questions usually elicit someone to post an actual code sample — the "give them a fish" approach.   I'm wondering what the community thinks about this. I'm thinking we're making lazy people even lazier with the latter approach. The person just scrapes the code off the response and into his source and off he goes without being any smarter. The person is going to repeat the same behavior the next time he is stuck. Although I'm fine with people choosing to maintain their intellectual status-quo, is SE encouraging the wrong behavior?


In C# I usually use String when I'm utilizing a method and string when declaring a variable. I read elsewhere that this is the preferred method to keep things clean and that made sense to me. In Visual Studio 2015, I'm getting a new message I haven't gotten before when I use String: Name can be simplified. The VS suggestion is to use string instead.  Why is string now preferred over String in VS2015 whereas it wasn't in 2013??  Not a duplicate of . That one asks what the difference is overall, I'm asking why VS is now suggesting one over the other; I don't know if a technical difference has changed or something to that effect.

Example (note the case):  string s = "Hello world!"; String s = "Hello world!";   What are the guidelines for the use of each? And what are the differences?


I'm trying to get an intuition about choosing the right "k" for  K-Fold validation. Is the following right?  Average of the OOS MSEs should generally decrease as k increases.  Because, a bigger "k" means the training sets are larger, so we have more data to fit the model (assuming we are using the "right" model).  Variance of the OOS MSEs should generally increase as k increases.  A bigger "k" means having more validation sets. So we will have have more individual MSEs to average out. Since the MSEs of many small folds will be more sparse than MSEs of few large folds, variance will be higher.  Thank you! :)

How do  methods compare in terms of model variance and bias?   My question is partly motivated by this thread: . The answer there suggests that models learned with leave-one-out cross-validation have higher variance than those learned with regular $K$-fold cross-validation, making leave-one-out CV a worse choice.  However, my intuition tells me that in leave-one-out CV one should see relatively lower variance between models than in the $K$-fold CV, since we are only shifting one data point across folds and therefore the training sets between folds overlap substantially.  Or going in the other direction, if $K$ is low in the $K$-fold CV, the training sets would be quite different across folds, and the resulting models are more likely to be different (hence higher variance).  If the above argument is right, why would models learned with leave-one-out CV have higher variance?


I have a WPF application (VB). I initialize a TextBlock item, when I click in a button,  the TexBlock content changes from an empty string ("") to a "foo" string.  I would like to get the value (you know, select it and then copy/paste) but I cant.  What kind of property I have to change in the TextBlock item in order to have this feature on ?  Thanks in advance the community !

How to allow TextBlock's text to be selectable? I tried to get it to work by displaying the text using a read-only TextBox styled to look like a textblock but this will not work in my case because a TextBox does not have inlines. In other words, how to make it selectable?


It seems there's no way to upload images from the App. This can come really handy at different instances and would be a great addition.

I would like to request implementation of uploading images to questions/answers from the Stack Exchange Android app, especially now as it would definitely help uploading screenshots for reporting bugs and feature requests.


I know people sometimes write unclear questions. I think some of them can never figure out how to make their question clearer. I think for some of them, the only way they're ever going to learn is if somebody makes an attempt to try and guess what they're confused about. Then they might slowly learn from experience how to write a question in a way that will get them the answer they were looking for. Also, sometimes they might resolve their own confusion later and might then answer their own question explaining it and mark it as accepted but that can't be done if it's closed or deleted. Once they do that, that might also give other Stack Exchange users insight on what types of answers tend to solve the author's problem. Everybody has a limit in how much quickly they can gain knowledge. It may be a good idea to adopt the following point system with points that are distinct from reputation points and are more like money where you can buy something if you have enough. Everyone has a site specific point system for every Stack Exchange website and a network point system. A main site is completely distinct from its meta site for points. Everyone starts with 1 point on each of them. On each website, their number of points for that website goes up by 1 every 30 days until it reaches a maximum of 5 and it goes down by 1 each time they ask a question on that website. Also, each time they ask a question anywhere on the network, the number of points for the network goes down by 1 and it goes up by 1 every 30 days until it reaches a maximum of 5. They can only ask a question on a website when they have at least 1 point for that website and at least 1 point for the network. Investing less time studying one subject doesn't seem to enable you to increase the amount of time you invest in studying a topic you're already investing a lot of time in by much. This way, people will ask fewer questions for the amount of knowledge they gained and they'll have more of a tendency to all be unique and different. Also, more attention will be drawn to each question on average. As a result of more attention drawn to each question, some people would have so much time to invest in a single question that if they had the right skills, they could figure out how to interpret the question when it's unclear.

I'm relatively new to Stack Overflow and already have experience with getting both a question and an answer deleted.  I understand why  was closed, but the closing happened too fast. The first time I looked at my question after posting it, it was already closed; I didn't get the chance to respond.  The deletion of  was done by mistake. The deleter wrote that I should have deleted the answer by myself to avoid bothering the moderators. That was offensive, IMO.  I suggest implementing a time period, e.g. one day, during which questions cannot be closed. That way, authors would have the chance to explain the causes of their answers.


I have constructed two variable importance plots in r using random forests regression the dependent variable is wheat yield and the independent variables are topographic and vegetative parameters. I am wanting to know which topographic/vegetative variables have the most importance influence on wheat yield. I have done this for two years of data.  The variable importance plot is shown below for both years.  How do I interpret this? the node purity for the two years is different?  Also, how do I know which plot is most accurate?  The variation explained in 2015 is 70%. while the variation explained in 2016 is 40% (the graph for 2016 looks more accurate though?) - please correct me if I am mistaken.  library(randomForest) rf1 <- randomForest(Yield_2015~TWI +Upslope_length+ Curvature + Aspect+Slope+NDVI_2015+SAVI_2015,                 data=Topo_yield) rf1$importance varImpPlot(rf1,main="Important variables for Yield 2015") rf2 <- randomForest(Yield_2016~TWI +Upslope_length+ Curvature + Aspect+Slope+NDVI_2016+SAVI_2016,                 data=Topo_yield_16) varImpPlot(rf2,main="Important variables for Yield 2016")

I've been playing around with random forests for regression and am having difficulty working out exactly what the two measures of importance mean, and how they should be interpreted.  The importance() function gives two values for each variable: %IncMSE and IncNodePurity. Is there simple interpretations for these 2 values?  For IncNodePurity in particular, is this simply the amount the RSS increase following the removal of that variable?


I can successfully run a .cmd file by typing its name (tsc in this case):  C:\Windows\system32>tsc --version Version 1.0.3.0   It instantly prints the result and terminates.  There is no tsc in C:\Windows\system32, so presumably it is being launched somewhere from a location specified in my %PATH%. I've searched through the drive and found a bunch of tsc.cmd files. How can I know, which of them is being launched?  Related, probably a duplicate:

Is there an equivalent of the Unix  command in Windows?   So that I could figure out where commands I can run actually is.


Why is Blender not saving my render after I already set the output location This seems to be themost common problem I see in all the forums Ive read so far, yet after doing it, its still not saving anything? I do Render>Render image and see the render in blender but its not in the folder I specified

Every time I render an image and try to save it, it just disappears. How do you exactly save a render? I am using a mac.


When I insert a cd in drive, it starts up the Parole Media Player.  How do I change that so the VLC Media Player, which is installed on my PC, becomes the default player?

I can't seem to set VLC media player as the default video player. I have gone to System Settings → System Info → Default Applications, and changed "Video" to VLC media player.  However, all movies still open with Movie Player (Totem) by default. The video default application setting appears to have no effect. I have tried changing the setting and logging out/rebooting, but it doesn't appear to work.  Is there some command-line magic that can work on this?


The task:  We have over 1500 .msg files in Salesforce, which are Outlook containers for Mail conversations plus attachments. The idea is to build a script, which downloads all files, extract each attachment and Mail conversation and uploading the files to Salesforce with the corresponding opportunities. It is convenient for us to use JSForce at the moment. Querying all the files in the database works fine. But VersionData is path to the actual document, not the document itself.  The Problem:  Here is the important part of the code:  conn.queryAll(oneLine`   SELECT ContentDocumentId,     ContentDocument.Title,     ContentDocument.FileExtension,     ContentDocument.LatestPublishedVersion.VersionData,     ContentDocument.LatestPublishedVersion.Id   FROM ContentDocumentLink   WHERE ContentDocument.FileExtension = 'msg' AND     LinkedEntityId = '${teamId}' `)   .then(result => {     result.records.map(document => {       if (!document.ContentDocument.LatestPublishedVersion) {         /* error handling */       }       const filename =         document.ContentDocumentId + '.' +         document.ContentDocument.FileExtension        const dataPath = document.ContentDocument.LatestPublishedVersion.VersionData       conn.request(dataPath)         .then(data => {           fs.writeFile(`./files/${filename}`, data, () => {             console.log(`downloaded ${filename}`)             /* Do stuff */           })         })         .catch(requestError => {           fs.appendFile(logNames.requestErrors, `${requestError}\n\n\n\n\n`,() => {})         })     }) ...   It will successfully download files, but they seem to be corrupted, because none of them can be viewed by any program suitable to open .msg files.  I had another approach like this:  ...   .then(result => {     result.records.map(document => {       if (!document.ContentDocument.LatestPublishedVersion) {         /* error handling */       }       const filename =         document.ContentDocumentId + '.' +         document.ContentDocument.FileExtension        const fileDesc = fs.createWriteStream(`./files/${filename}`)         .on('error' , error => {           console.error(error)         })       conn         .sobject('ContentVersion')         .record(document.ContentDocument.LatestPublishedVersion.Id)         .blob('VersionData')         .pipe(fileDesc)         .on('error', error => {           console.error(error)         })         .end(() => {           console.log('Closing FD')           fileDesc.close()         })     })   Here, nothing happend. Nothing was downloaded and no error was printed or logged.  The documentation seems to be not up-to-date or at leat not helpful to me. I appreciate every help i can get.

I am trying to retrieve VersionData with a standard REST API call from a VisualForce Page a then upload it to a S3 bucket but end up with corrupted files. I believe this is an encoding problem on the client side as plain text or CSVs work like a charm. I can upload VersionData from Apex but there are heap and request size limitations so I need to send the data from the client.   This is the call and returned string, I tried changing mimeType and encoding on both sides (SF call and S3 upload) with no luck.   Any ideas how to properly process images or pdf files? Thanks a lot  THE PROBLEM IS NOW SOLVED  Files should not be treated as strings. I solved the problem by leaving jQuery's ajax as I did not succeed to request a response type. By switching to plain JS and making a GET call (XMLHttpRequest) with response type set to blob I received an Object, instead of a string. Base64 string can be then retreived using JS FileReader.


Trying to understand the multivariable proof of the least square estimations. I have difficulty differentiating the loss function with regards to $\vec{\beta}$. \begin{align}   \frac{\partial L\left(D, \vec{\beta}\right)}{\partial\vec{\beta}}     &= \frac{\partial \left(Y^\textsf{T}Y - Y^\textsf{T}X\vec{\beta} - \vec{\beta}^\textsf{T}X^\textsf{T}Y + \vec{\beta}^\textsf{T}X^\textsf{T}X\vec{\beta}\right)}{\partial \vec{\beta}} \\     &= -2X^\textsf{T}Y + 2X^\textsf{T}X\vec{\beta} \end{align} I am stucked when we have to derive with regards to $\beta$ a term containing $\beta^T$. How should that deal be with ?

It's stated that the gradient of:  $$\frac{1}{2}x^TAx - b^Tx +c$$  is   $$\frac{1}{2}A^Tx + \frac{1}{2}Ax - b$$  How do you grind out this equation? Or specifically, how do you get from $x^TAx$ to $A^Tx + Ax$?


Let's say there's a series of the form $$S=\frac{1}{10^2}+\frac{1\cdot3}{1\cdot2\cdot10^4}+\frac{1\cdot3\cdot5}{1\cdot2\cdot3\cdot10^6}+...$$ Now i had written the rth term as $$T_r=\frac{1\cdot3\cdot5....(2r-1)}{1\cdot2\cdot3.... r\cdot10^{2r}}=\frac{2r!}{r!\cdot r!\cdot2^r\cdot10^{2r}}$$ I came to the second equivalence by mutliplying and dividing the first expression with $2\cdot4\cdot6....2r\;$and then taking out a power of 2 from each of the even numbers multiplied in the denomininator.  From the looks of it, these expressions tend to give the idea of being solved using binomial most probably the expansion for negative indices but I don't understand how to get to the result from here

How to find infinite sum How to find infinite sum $$1+\dfrac13+\dfrac{1\cdot3}{3\cdot6}+\dfrac{1\cdot3\cdot5}{3\cdot6\cdot9}+\dfrac{1\cdot3\cdot5\cdot7}{3\cdot6\cdot9\cdot12}+\dots? $$   I can see that 3 cancels out after 1/3, but what next? I can't go further.


I have installed owncloud-client from Ubuntu repositories. But it opens a popup on every startup, which informs about a new version. Therefor I decided to get the update from a 3rd party repository and I have added deb http://download.opensuse.org/repositories/isv:ownCloud:devel/xUbuntu_12.04/ / so my sources.  But now my Software Updater opens a dialog titled Not all updates can be installed and suggests to make an Partial Upgrade. What does that mean, what will the partial upgrade do with my Ubuntu and what consequences do I have to expect?

So here is my story...  I was doing upgrades to ubuntu the other day, and the power went out right in the middle of the upgrade, so now when I try to do upgrades it keeps asking me if I want to do a partial upgrade. I have heard this is bad and should be avoided, I also know there is a way to fix this via the command line, but I can't remember how, nor can I find anything on the internet.  Any help would be appreciated. Thanks


Is there any way I could find how much bytes are allocated for RandomArray in this code  #include<stdio.h> #include<stdlib.h>      int main()     {     int *RandomArray;     int n;     srand(time(NULL));      RandomArray=malloc(sizeof *RandomArray * (rand()%11));     printf("%d  %d",sizeof(RandomArray),sizeof(*RandomArray));      return 0;     }   Also I don't know whether above code will ever have any kind of practical usage. But I am looking from programming perspective.

I've allocated an "array" of mystruct of size n like this:  if (NULL == (p = calloc(sizeof(struct mystruct) * n,1))) {  /* handle error */ }   Later on, I only have access to p, and no longer have n. Is there a way to determine the length of the array given just the pointer p?  I figure it must be possible, since free(p) does just that. I know malloc() keeps track of how much memory it has allocated, and that's why it knows the length; perhaps there is a way to query for this information? Something like...  int length = askMallocLibraryHowMuchMemoryWasAlloced(p) / sizeof(mystruct)   I know I should just rework the code so that I know n, but I'd rather not if possible. Any ideas?


I want to show my custom CTI Adapter only on Console but not on all pages (Home, Contacts & Etc.). How can I do this,  Screen where I don't want to show,   Screen where I want to show,   Note: I am new to Salesforce. So, assuming that this is a valid question!

Open CTI Softphone VF page is showing in salesforce left side. How to remove this ? Screenshot attached


I am getting started coding a win32 windows application and ran across a c++ syntax that I haven't seen before in some  on the MSDN.  LRESULT CALLBACK DemoApp::WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) {      /* Code omitted for clarity */      ::SetWindowLongPtrW(     hwnd,     GWLP_USERDATA,     PtrToUlong(pDemoApp)     );      /* Code omitted for clarity */  }   I am used to seeing a class / namespace preceding the :: operator.  What does this mean when there is no preceding identifier.  Also, is there a name for this construct so I can efficiently Google more information?  Thanks!

In C++, what is the purpose of the scope resolution operator when used without a scope? For instance:  ::foo();


When you hold a can of spray and press on it to let out some spray, you feel the can is getting colder. How does this happen? For temperature to decrease you have to take energy out of the system, how does the temperature of a spray can decrease by simply letting some air out? Many explanations I have heard don't make sense to me, like "molecules are more spaced apart so heat is more spread out". Temperature isn't a measure of energy density right? Temperature is the average kinetic energy of the molecules. Energy is removed from the system because some particles exit the system, but shouldn't the average kinetic energy remain constant? PV=nRT, less n and less P give us constant V and T.

We all use deodorant and they always feel cold, why is that?  Is it because it is liquid inside the bottle and a gas when it is released?


Show that $\mathbb{Z}[\sqrt{-2}]$ is unique factorization domain. I am unable to proceed. Any help, thanks in advance.

We're proving that $\mathbb{Z}[\sqrt{2}]$ is a Euclidean domain, using the norm function $$\nu (a + b\sqrt{2} ) = |a^2 - 2b^2|$$ and the first part says that since $\nu (a + b\sqrt{2} ) = |(a + b\sqrt{2})(a - b\sqrt{2})|$ it's clear that $\nu (xy) = \nu(x) \nu(y)$? ... Can someone please explain to me how this is clear?


package com.sm.mongo;      import com.mongodb.MongoClient;     import com.mongodb.MongoClientURI;     import com.mongodb.client.MongoCollection;     import com.mongodb.client.MongoDatabase;     import org.bson.types.ObjectId;      public class JavaMongoConnection {      public static void main(String[] args) {          //System.setProperty("jdk.tls.trustNameService", "true");          MongoClientURI uri = new MongoClientURI(                 "mongodb+srv://admin:admin123@cluster0-bkruu.mongodb.net/test?retryWrites=true&w=majority");              MongoClient mongoClient = new MongoClient(uri);             MongoDatabase database = mongoClient.getDatabase("test");      } }   This is my code, and whenever I run this code, I get the error:  Exception in thread "main" java.lang.NoClassDefFoundError: com/mongodb/MongoClientURI   I looked at  and I tried their solution where I went to Run Configurations --> Dependencies and looked under Classpath Entries to make sure that I have bson-xxx.jar, mongodb-driver-xxx.jar, and mongodb-driver-core-xxx.jar listed. I have these listed and despite this, I keep getting the same error as in that stackoverflow post.   Any help would be appreciated.

I am getting a NoClassDefFoundError when I run my Java application.  What is typically the cause of this?


John is the mentor of Anna. John introduces Anna as:    "Anna, whom I've had the pleasure of being the mentor of".    Would the following be more correct?   "Anna, of whom I've had the pleasure of being the mentor"

Like many others, I commonly find myself ending a sentence with a preposition.  Yes, it makes me cringe.  I usually rewrite the sentence, but sometimes (in emails) I just live with it.  To, with... you know who you are.  Should I keep fighting myself on this one, or is it okay in some circumstances?


I have my dock preferences to auto-hide. When I plug in my Cinema Display it works as expected: the dock hides when the mouse isn't hovering over it. Is it possible to disable this functionality ONLY on the Cinema Display and keep it happening on the macbook?  For clarification: When my cinema display is plugged in I should be able to see the dock at all times on my cinema display, but it should still auto hide on macbook screen.

When at home I use my 13" MacBook Pro hooked up to an 27" external monitor. When working on my 27" screen I prefer to have a visible dock at all times. I have enough screen real estate to afford this luxury.  When I'm on the road working on my 13" screen I prefer to automatically hide the dock as it really gets in the way when screen real estate is limited.  I now manually switch between enabling and disabling hiding (using ⌥⌘D) but I would prefer this to happen automatically. Can I enable hiding the dock on my MacBook monitor and disable hiding the dock on my external monitor?


I don't know how to explain the issues at hand in a way that nonphysicists are certain to understand. Can anyone point me to some resource (book, video, it doesn't really matter) that will help me?

It is well known that quantum mechanics and (general) relativity do not fit well. I am wondering whether it is possible to make a list of contradictions or problems between them?  E.g. relativity theory uses a space-time continuum, while quantum theory uses discrete states.  I am not merely looking for a solution or rebuttal of such opposites, more for a survey of the field out of interest.


public abstract class BaseClass     {         private int id;          public int Id         {             get { return id; }         }      } public class SubClass : BaseClass     {         public SubClass(int id)         {             this.id = id;         }     }  How would I make the constructor work if I want id to be private and Id to be read only ? And should I also have the constructor in my BaseClass even tho I want it to be abstract class ?

If I inherit from a base class and want to pass something from the constructor of the inherited class to the constructor of the base class, how do I do that?  For example, if I inherit from the Exception class I want to do something like this:  class MyExceptionClass : Exception {      public MyExceptionClass(string message, string extraInfo)      {          //This is where it's all falling apart          base(message);      } }   Basically what I want is to be able to pass the string message to the base Exception class.


I have this class definition in .h file:  class PolygonPath {   public:     template<class T> explicit PolygonPath(const Polygon<T> &);     template<class T> Polygon<T> toPolygon() const; }   In .cpp file, I define my methods. Then, I would like to define explicit template for   Polygon<float> and Polygon<long>. So, I define them like that:  template class PolygonPath::PolygonPath<float>(const Polygon<float> &); //Fail template class Polygon<float> PolygonPath::toPolygon<float>() const; //Ok template class PolygonPath::PolygonPath<long>(const Polygon<long> &); //Fail template class Polygon<long> PolygonPath::toPolygon<long>() const; //Ok   For constructor, I'm not able to define an explicit template specialization. I have this error at compilation: "error: ‘PolygonPath’ is not a class template". I also try with this syntax:  template <> PolygonPath::PolygonPath(const Polygon<float> &)   It compiles but I get another error at link: "undefined reference to `urchin::PolygonPath::PolygonPath(urchin::Polygon const&)'".

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


Upon visiting Meta Stack Exchange today, I noticed that my gravatar had been replaced with the default geometric art image.    Upon further research, it appears that it is still there on , , and , but seems to be gone    .  I used to have this same gravatar on all Stack Exchange sites.  What caused it to stop working?  How can I get it back?

I have had the same network-wide profile avatar for many years; it's a custom image which I installed nework-wide soon after I registered for Stack Overflow back in 2011. I still see that image e.g. on  and  but not, for instance, on this site, or e.g. on   (The example originally linked to my Unix & Linux profile instead of Super User but I experimentally changed my profile back to the gravatar one there.)  I routinely update my profile presentation text every few months, and did so again a few days ago. Comments below seem to indicate that others who recently edited their profile are experiencing the same problem.  My preferred avatar is a Gravatar which is connected to my email address, which has always been the same (MD5 091f411d57db5be8298e057a32e5ad72). The replacement seems to be a generic identicon with a different MD5. I don't recall seeing this identicon as an option in my profile before:    You'll notice that the gravatar is still visible as an option, but I can find no way to replace it on all sites in one go. I switched back to the gravatar one on Unix & Linux and noticed that the help next to the "Save" button says     Your profile will be updated on all public communities.   but alas, that did not in fact happen. Do I really have to go over 170+ member sites and manually select my gravatar on each?


What is the maximum voltage that can be put on a metal sphere before electrons fly off it or the metal itself explodes due to electrostatic forces?

Suppose I charge a sphere and leave it in vacuum for 10 years. After that time, I want its surface charge density to be in the order of 10^5C/m^2. Would that be possible? Would it depend on the material used and how? Would adding or removing electrons make a difference (positively vs negatively charged)?


FYI: this is for a simple quiz with just a single input field for each answer.  I have the following Javascript if statement to check if the value entered into an input field is correct (in this case, if the value entered is 'england').  $('input').keyup(function () {     if ($(this).val().toLowerCase() == 'england') {         //Stuff     } else {         //Other Stuff     }; });   However, I want to allow for alternative spellings, so I need a few possible answers for each question - it seems sensible to use an array for this as so...  var ans1 = new Array(); ans1[0] = "England"; ans1[1] = "Englund"; ans1[2] = "Ingland";   How can I change my if statement to say 'if the input field value equals any of those values from the array, then do the following'?  Any help would be greatly appreciated! Thank you.

What is the most concise and efficient way to find out if a JavaScript array contains a value? This is the only way I know to do it: function contains(a, obj) {     for (var i = 0; i < a.length; i++) {         if (a[i] === obj) {             return true;         }     }     return false; }  Is there a better and more concise way to accomplish this?


I have to create a Tikz picture of a limacon which is given in polar coordinates by the equation r = 0.5 + cos(θ) for θ between 0 and 2π. Note:makethe x-axis between 􀀀0.2 and 1.7 with a scale of 3 and the y-axis between 􀀀1 and 1 with a scale of 3.  My document is of the form:  \documentclass{article} \usepackage{tikz}  \begin{document}  \begin{figure}[h!]  \centering  \begin{tikzpicture}[xscale=3, yscale=3, domain=-0.2:1.7]  \draw[<->] (-0.2, 0) -- (1.7, 0)   node[above]{$x$};  \draw[<->] (0,0) -- (0,5)   node[right]{$y$};  \draw[colour=purple, smooth]   plot(HERE);  \end{tikzpicture}  \end{figure}  \end{document}   However, I do not know how to write the function in '' plot(HERE); ''. Can anyone help me? Thanks.

How would I create a TikZ picture of the limaçon $r=0.5+\cos(\theta)$?   Would I have to convert it to cartesian coordinates or is there a way to plot the polar form?


I am getting following error while running the command to update apache. $ apt-get install -f apache2  The following packages have unmet dependencies:  apache2 : Depends: apache2-bin (= 2.4.41-1+ubuntu18.04.1+deb.sury.org+5) but it is not going to be installed E: Unable to correct problems, you have held broken packages.  I checked almost all the answers here but none of them resolved the issue. I also tried all the commands to list the broken packages but none of them shows the list. I upgraded the Ubuntu today and now getting this error. Can someone help on this?

After upgrading from 10.04 to 12.04 I am trying to install different packages.  For instance ia32-libs and skype (4.0).  When trying to install these, I am getting the 'Unable to correct problems, you have held broken packages' error message.   Output of commands:  sudo apt-get install -f Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.   After running this:  sudo dpkg --configure -a foo@foo:~$ sudo apt-get install -f Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.


I'm playing around with the bash shell for Windows 10 and I noticed that I was in the root mode (whoami returns root). I'm still fairly fresh at bash but I know enough to know that using root mode is dangerous if you don't absolutely know what you're doing (like me).   exit and Ctrl+D don't work.  Any tips to log out of sudo?  EDIT: I created a new user account with adduser and it took me out of root mode.

I installed the WSL Bash on Windows 10 and set my user to e.g. 'abc' but now I want to change it to something else.  How can I change the user name of the user I'm logged in as?  When I open bash it automatically logs me in with my current user.


If I understand things correctly the popular COVID 19 vaccine gives the body RNA that teaches the body cells to create a protein that looks like the virus. And then the body learns to fight against it. Now my question is, why not to give the body directly the protein and skip the RNA stuff. If it's hard to create that protein, why not use animals for that. Many people are against the vaccine because of the RNA, so maybe it's a better approach?

How do mRNA vaccines work? To my intuitive understanding, for an mRNA vaccine to work, the mRNAs injected into the patient need to first enter a cell and get translated into proteins. Those proteins must then somehow exit the cell so that they can be seen by T cells. An mRNA vaccine hence appears considerably more complex than a traditional/protein vaccine. I envision these three steps as critical  mRNAs get in cells mRNAs get translated proteins exit cells  Am I right to think that such vaccine must go through these steps (or is there some other way around)? I failed to find anywhere explanations about these three steps? Could you give some explanations what exactly we inject to ensure these three steps will happen? What are the advantages of mRNA vaccines over traditional vaccines? I was thinking of potential advantage of such a complex vaccine and thought that maybe it has the advantage of inputting proteins into the bloodstream at a rate (rate that decreases over time with the half-life of the mRNA) while a traditional/protein vaccine makes a single large input of protein into the bloodstream. I am thinking, that might reduce risks of strong inflammation caused by the vaccine. Would it be true? I read from   RNA vaccines can be produced faster, more cheaply, and in a more standardized fashion (with fewer error rates in production), which can improve responsiveness to serious outbreaks.  Can you please explain why this is true?


If it were possible to launch a projectile at the speed of light from a body with the mass equal to that of our sun but a density such that its escape velocity was the speed of light how far would it go into empty space before its velocity dropped to one metre per second and how long would it take?  The question was only partly related to light escaping from dense bodies but before seeking the answer to light i will re-frame the question as follows;  If a projectile were launched from a body with the mass equal to that of our sun but a density such that its escape velocity was only 1/100th of the speed of light how far would it go into empty space before its velocity dropped to one metre per second and how long would it take? This move the question away from relativity issues. I think the distance is actually 2*G*M but how long does it take?

I have a couple of questions about light here, and sorry of they are silly..  So since anything that goes beyond the event horizon can't go out, so what if a light beam was pointed somewhere behind the event horizon to the outside, would light have a slower speed then get sucked back? and what if the light particles were somehow exactly on the event horizon, would the light stand still?  And why can't light stand still? why does it always move at that really high speed?


Why is $y{(\log_a(x))} = \log_a{(x^y)}$?   I feel like I'm missing something here. Sorry if I put the title wrong..

While I understand the proof of the power rule for logarithms for positive integers, I can not prove them for fractional and negative powers. Also curious to know what would a proof for irrational powers look like?


Trying to make a script that will copy some files between machines, and unzip them. (Running CentOS 6.7) Everything seems to work except the unzip part,   This is the command giving me some issues,   ssh -i /root/.ssh/qasynd.key file_sync@10.5.107.82 'unzip /home/root/tmp/*.zip'   Ignoring the user/directory structure as that's just for the command, what could cause this? I did try to point it to /usr/bin/unzip as opposed to just unzip.

I put together a script to do some file operations for me. I am using the wild card operator * to apply functions to all files of a type, but there is one thing I don't get. I can unzip all files in a folder like this  unzip "*".zip   However, to remove all zip files afterward, I need to do   rm *.zip   That is, it does not want the quotation marks. The unzip, on the other hand, does not work if I just give it the * (gives me a warning that "files were not matched").   Why is this different? To me, this seems like the exact same operation. Or am I using the wild card incorrectly?   in Unix do not really go into this, and I could not locate anything in the rm or zip docs.  I am using the terminal on a Mac (Yosemite).


There are many tools around to block unwanted SMSs. Samsung Galaxy S3's Jelly Bean offers a native call&sms blocker too. But some senders are not phone numbers, they are alphanumeric strings. I would like to get rid of this spammer, and my provider says they can't block SMSs on their own. Currently, I wouldn't like to block "anonymous" SMS because I haven't yet received spam (better say mobbing) from undisclosed/private senders. I've tried to use , but it doesn't seem to support named senders too. Any suggestions on how to deal with this?

In India, we often receive SMSs which do not actually have a number, but instead, have a name like 'VK-AMSWAN'. SMS blockers like Truecaller don't have any facility to recognise such senders, and keep asking for a number to block.  How do I block such senders? I cannot blanket block all unknown SMSs because even banking information comes from such named senders.  Edit: When using third party SMS apps like chomp SMS, there is an option to show contact number below contact name. Guess what it shows for the spam?  VK-AMSWAN (name)  VKAMSWAN (where the number shows up for other contacts)  -_-  Edit 2: Thank you so much for your suggestions, guys. :) But it seems SMS blocking isn't as well developed as call blocking is. Truecaller actually rejects spam calls without you ever knowing about them. No SMS blocker I've seen has this facility so far. All they do is receive the messages and hide them. If someone can locate a method to fully block spam SMS, please do tell. :)


If $A$ is an $n\times m$ matrix, is the formula $im(A)=im(AA^T)$ necessarily true? Explain.  I believe this to be true when $n=m$ but am unable to prove if it's true where $n\neq m$. I also don't understand how to prove either way with a formula.  any help would be appreciated.

How can I prove $\operatorname{rank}A^TA=\operatorname{rank}A$ for any $A\in M_{m \times n}$?   This is an exercise in my textbook associated with orthogonal projections and Gram-Schmidt process, but I am unsure how they are relevant.