I am using Windows 10 EN on a Dell XPS 13. I tend to install updates as soon as Windows asks me to but I've realized that it was not getting feature updates for some time. Don't know why and actually not important at this point. I am on 1803 and the latest is 1909.  I've tried installing the update through windows update and failed several times. Tried everything Windows Update Troubleshooter recommended, no luck. Contacted MS Support, they directed me to update with an ISO file, still failure.  MS Support says the latest update is 1909 and since I missed many major updates, I am having this problem. I should give up on trying an in-place update, backup my files and install a clean 1909. I don't want to do that.  The question is: How can I install feature updates since 1803 one-by-one, manually (1809, then 1903, then 1909) ?

I need to repair my Windows 10 installation. Where can I get a clean ISO (with install.wim, no Install.ESD, so that I can run DISM against the WIM) of the specific Windows 10 build required for this?  In my case, I need the Anniversary update (Build 14393), Creators Update (Build 15063) or Fall Creators Update (Build 16299.15).


If there was a post reported with  tag months or even years ago on Meta Stack Exchange or a per-site meta, and now the bug is fixed and working fine, but nobody has changed the status to , how can I notify someone?   I can simply add a comment to the post saying the bug is fixed, @-mention one of the moderators - but I feel this adds unwanted noise to the post.   I can flag the question with in need of moderator intervention to add my comments about the bug, it was fixed.   What is the correct way to notify about the post to the moderator?

Occasionally I see an old Meta post that has no status tag (like ), but from the answers it looks like the question is resolved.  Example:  should be  since the answers say HTTP compression actually is enabled.  Is it worth flagging these questions, or is that a waste of time?


I try to solve the following task:  Let $(\Omega,\mathfrak{A},\mu)$ be a measurable space and $\mu(\Omega)<\infty$. Let $(f_n)_{n\geq1}$ be a sequence of integrable measurable functions $f_n:\Omega \rightarrow [-\infty,\infty]$ converging uniformly on $\Omega$ to a function $f$. Prove that $$\int f d\mu = \lim\limits_{n\rightarrow \infty} \int f_n d\mu$$.  What I thought: uniformly convergence of $f_n \rightarrow f$ means that $f$ is continuous and therefore measurable. Now I thought that I could use the dominated convergence theorem to show the equality.  uniformly convergence means $\lim\limits_{n\rightarrow \infty} \sup \{|f_n-f(x)|:x\in \Omega\}=0$ so I think I can define a function $s(x):=\sup \{|f_n-f(x)|:x\in \Omega\}=0$ which dominates all the $f_n$ and apply the theorem. But I'm not sure, if this is the correct way.

Let $f_n \in L^1$ such that $f_n\rightrightarrows f$. Then I want to conclude that If $\mu(X)<\infty,$ then $f\in L^1$ and $\int f_n\to\int f$, so I want to make use of the Dominated convergence theorem, the thing is that I don't know which would be my dominating function.  I was trying to figure out if the measure could play that role, but after thinking a little bit I have realize that the measure doesn't have to be bigger than the absolute value of the functions of the sequence.  Another thing I was thinking of, is to apply Fatou's lemma, but I can't ensure that my functions are positive.  So, Can someone help me to prove this theorem please ?  Thanks a lot in advance :).    NOTE: I think this theorem is taken from Folland's Real analysis, modern techniques, and their aplications 2nd Edition :), This is to have all the definitions so we can talk the same language as in the book (this is, same notation and theorems or machinery)


I have a line shapefile tc_line with 166 segments and a point shapefile tc_point with 8 points, and I loaded them into PostGIS database with DB manager:    and the following were their attribute table:   table tc_line (part)      table tc_point     Because these points are just nearby the line, not right on it, I try to use ST_ClosestPoint first, then use ST_Split to split the line.  @amball, I tested your code in the edited answer and the result showed:  SELECT ST_Split(ln.geom, ST_Collect(newpt_geom)) FROM tc_line AS ln,      (SELECT ST_ClosestPoint(ST_Collect(ln.geom), pt.geom) AS newpt_geom      FROM tc_line AS ln, tc_point AS pt GROUP BY pt.geom) t1 GROUP BY ln.geom;     The result was strange because it had 166 rows just the same as the rows original line had, which means that ST_split didn't work. So I loaded the result as new layer to check it.    But In QGIS I could not see it even I set its CRS, and as I wanted to export it as ESRI shapefile, error message showed up:  Export to vector file failed. Error: creation of layer failed (OGR error:Geometry type of `Geometry Collection' not supported in shapefiles. Type can be overridden with a layer creation option of SHPT=POINT/ARC/POLYGON/MULTIPOINT/POINTZ/ARCZ/POLYGONZ/MULTIPOINTZ. )   So I tried to split the line with 2 stages:   ST_ClosestPoint ST_split   In the first stage I ran the code:      SELECT      tc_point.id as pointid,      St_ClosestPoint(ST_collect(tc_line.geom), tc_point.geom) as closest,     st_astext(St_ClosestPoint(st_collect(tc_line.geom), tc_point.geom)) as text     FROM tc_point, tc_line GROUP BY tc_point.id;   The result were fine: (8 closest points)    and I successfully loaded as new layer tc_proj, and its attribute table:    Then I ran stage 2:  SELECT ST_Split(ln.geom, ST_Collect(tc_proj.geom)) from tc_line as ln, tc_proj GROUP BY ln.geom;   error showed up:  Splitting a Line by a GeometryCollection is unsupported   I am newbie to SQL and SQL open source such as PostGIS. How to work the above task successfully? I am working with PostGIS 2.2.1    Update#1  @amball, I tested your following code,  SELECT ST_Split(ln.geom, newpt_geom) FROM tc_line AS ln,      (SELECT ST_ClosestPoint(ST_Collect(ln.geom), pt.geom) AS newpt_geom       FROM tc_line AS ln, tc_point AS pt      GROUP BY pt.geom) t1 WHERE ST_Intersects(ln.geom, newpt_geom);   and its result,    I don't know why there were 4 rows in the result, and I could see nothing using Create a view, also, Load as new layer outputted nothing. Thus, I still can't determine whether result is correct.

I have a line shapefile and a point shapefile, and   the line has just one segment     and its attribute table,     the point shapefile has points near the line above, not on it     and the close look,    I want to use ST_split to split this line at locations which are nearest to the points I want to get the original line with more segments(because being split). For example, find the location on the line, which is the nearest to the point, and split the line at this location(star).    I loaded this line shapefile into PostGIS and here's my SQL code in PostgreSQL,  select ST_AsText(ST_Split(ST_GeomFromText('LINESTRING(0 0, 247907.60 2746404.62, 200    200, 400 400)'),        ST_Line_Interpolate_Point(ST_GeomFromText('LINESTRING(0 0, 247907.60 2746404.62, 200 200, 400 400)'), 0.2)))   And I checked the table of this line, it wasn't being splited.  Where did I make mistakes？ I am new to use ST_split, please give me any suggestion, thanks.  I am using QGIS 2.2, PostgreSQL 9.2 and PostGIS 2.0.4 under Windows 8.1 x64.    Update#1  @simplexio, I used your code,  select ST_Line_SubString(ST_GeomFromText('LINESTRING(0 0, 247907.60 2746404.62, 200 200, 400 400)'), 0 , 0.200 ) as geom into split_line ;   and got a new table named split_line,    But as I used the following code you posted,  SELECT ST_Line_SubString(line, 0, ST_Line_Locate_Point(l.line, p.point)) as from_start_geom,        ST_Line_SubString(l.line,ST_Line_Locate_Point(l.line, p.point), 1) to_end_geom, l.line_id, p.point_id FROM lines l , points p  WHERE l.line_id = 1 , p.point_id = 1   I got a syntax error,    How to fix this and move on？ And where should I assign the line I want to split as input of st_split？


Setup is:   A main router, then a second router which connects from its WAN port to a LAN port of the main router. This second router's goal is to establish a separated network for guest devices.  I disable the DHCP function of the second router, and set a static IP (which is different than the IP of the main router). For example if the main router is 190.160.0.1, then I would set second router to 190.160.0.20).  If guests connect  to the second router via LAN or WiFI, would the guest's devices be able to "interact" with the devices connected to the WIFI of the main router? Could there be any kind of interaction on Layer 2 or 3?  Is it correct to connect the WAN port of the second router to a LAN of the main router, or should it be  LAN to LAN?  If this setup does not fulfill the "separation" criteria, what changes are needed to achieve separated networks (using a two routers approach - without the need of VLANs)?

I'm trying to link two wireless routers with an Ethernet cable in order to expand my wireless network. Both routers need to provide wired and wireless Internet access.  I'd like to know the differences between the "LAN to LAN" and "LAN to WAN" connection methods, their advantages and disadvantages.


EDIT 2: My question was indeed a duplicate or otherwise clouded in some of my own misunderstanding.  Apologies for the inconvenience.    EDIT: This question was closed as a duplicate, but the thread linked does not solve my problem.  My issue is that I cannot put any sort of \thanks, \footnote, or even \footnotemark inside of the second argument of \author.  Also, I am not adding a URL.  I am adding text.    I am struggling to add a \thanks to the second author (which should go at the bottom of the first page).  In the following, the only thing that's missing is (a) a number/symbol for the second author, and (b) a number/symbol for the footer that \thanks creates.  Putting thanks inside the second author full name threw an error.  I also tried \footnote, but didn't manage to make it work.    \documentclass[a4paper,11pt]{amsart} \usepackage{amsmath,amssymb,amsthm, amsfonts,color}  \begin{document}  \title{A paper}  \author[F. Author]{First Author} \author[S. Author]{Second Author}\thanks{for all the fish} \address{the department\\ a place} \email[F. Author]{fauthor@theschool.edu}  \email[S. Author]{sauthor@theschool.edu}    \maketitle  \begin{abstract} the abstract \end{abstract}  \section{intro} lots of good stuff   \end{document}     Hopefully this is easy to solve.  Thanks in advance!

What is the correct way to have a \thanks command for a specific author ?  I don't want to use \author{auth1 \and auth2} for obvious reasons (i.e. be able to distinguish the authors).  I have tried various options without success. Here is a rather minimal example where the two thanks are not attributed.  \documentclass{amsart}  \begin{document}  \title[short title]{Longtitle}  \author[Auth1]{Surn1 Auth1}  \author[Auth2]{Surn2 Auth2}  \address[Auth1]{adr1} \email{auth1@adr.org} \thanks{Network1}   \address[Auth2]{adr2}  \email{auth2@adr.org} \thanks{Network2}    \maketitle  \end{document}


I'm a beginner in both MongoDB and node.js. Actually, I'm trying to get the names of a particular document but I wonder how to do that. Let me elaborate in detail : if "a" is a collection which contains document named "student" and "student" contains fields like   {     "_id: "student",     "name": "alex",     "roll": "3",     "age":"13" }    then how to get the field names in this ["name","roll","age"] format By trying this:  db.collection("user").find({ "_id": "student" }).toArray(function(err, result) {     console.log(result) })   is giving all the fields with their values.

Say I create an object thus:  var myObject =         {"ircEvent": "PRIVMSG", "method": "newURI", "regex": "^http://.*"};   What is the best way to retrieve a list of the property names? i.e. I would like to end up with some variable 'keys' such that:  keys == ["ircEvent", "method", "regex"]


I'm currently starting out with C so I thought I'd try creating my own custom list. Here's the code:  #include <stdio.h>  struct list {     char data[10];     struct list *n; };  void clist(struct list *a) {     int j=(sizeof(a)/sizeof(a[0]));     j--;         for(int i=0; i<j-1; i++) {         struct list *next=&a[i+1];         a[i].n=next;      } }  int main() {      struct list first = {.data="one", .n=NULL};     struct list second = {.data="two", .n=NULL};     struct list third = {.data="three", .n=NULL};      struct list arr[] = {first, second, third};      struct list *p=&arr[0];      clist(p);      struct list looper = first;      while(looper.n!=NULL) {         printf("%s ", looper.data);         looper = *looper.n;     }      return 0; }   So basically I have a struct that saves a char array and a pointer. I initialize them and then I try to link them together by giving it to the clist method. There lies the problem: it seems clist isn't getting anything useful as the variable j stays at 0. If I do the whole size calculation before giving the array to the clist method, I'm getting the correct 3 as a result. Why is that?

First off, here is some code:  int main()  {     int days[] = {1,2,3,4,5};     int *ptr = days;     printf("%u\n", sizeof(days));     printf("%u\n", sizeof(ptr));      return 0; }   Is there a way to find out the size of the array that ptr is pointing to (instead of just giving its size, which is four bytes on a 32-bit system)?


I am looking for some high-level suggestions on how to build the following:  During the process of about two weeks, a few jobs will need to run a few times a day, at very precisely given times. These jobs include:   Pulling/pushing files from/to FTP servers. Running an SSIS (that's Microsoft's ETL solution) package. Running a C# program that's compiled as .exe.   All of this happens on Windows Servers.  As a programmer, my first thought was to write a tool in C# that can run for a couple of weeks, and just executes these other tasks at the given points in time. This sounds like overkill and difficult to maintain, though.  What would your solution be?

What's the Windows equivalent to cron, or for those of you unfamiliar with Unix, how does one schedule a program to run at regular intervals?


I want to take a String of words that are separated by spaces, and separate each word, and then compare it to another string.  import java.util.ArrayList; public class Test {     public static void main(String[] args) {      ArrayList<String> list = new ArrayList<>();     list.add("potato");     String a = "potato salad";      String[] x = a.split(" ");      System.out.println(""+x[0]);     System.out.println(""+list.get(0));      if(list.get(0) == x[0])     {         System.out.println("they same");     }     else     {         System.out.println("they not same");     } } }   When i print them, they both print the same string does that mean that the split method returns something other than an array of strings? How can I go around the problem to get the desired result.

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


I am a student reviewing multiple COVID tracing applications deployed in various countries around the world. Although I'm located in the US, I'm also interested in applications that other countries have deployed. As far as I understand, to do that I would need to find a VPN server in the country I am interested in and browse Play Store from there. It looks that people all around the internet advise to:  Connect to the VPN, Remove cache and data from Play Store, and Restart Play store.  However, this does not work for me. Play Store still lists only the applications available in the US and prices in US dollars. I have checked whether my VPN works and it does. whatismyipaddress.com shows that at least my search queries coming from the browser go through a foreign VPN server.

I'm travelling to country X. I want to install an application which isn't available in my country, but is available in country X; but I prefer to download and install it in advance, while the data connection is still cheap.  Unfortunately, the Play Stores does not allow me to install this app. Is there any way to circumvent this limitation?


How can I use the find command to locate directories that do NOT contain a particular file? E.g., if I have bunch of directories that should be under revision control, can I search and find the ones that do not have a .git sub-directory? Or, my project specifies that all modules should have a utilities.py file; how do I search to find which sub-directories do not yet have the required file?

How would I go into listing all directories that do not have a file with a given file name inside? e.g. given this tree  /   /a      README      file001      file002   /b      README      file001   /c      file003   I want to list the directories that do not have a file named README, in this case it would be directory /c. How would I do that? I can't think of any syntax using e.g. find.


I want to latex the following matrix    is there a solution without using arrays? Also, what will be the most efficient way to write this?  Any suggestion is appreciated.

I need to typeset a block matrix that is made of a 2X2 structure of blocks such that the (1,1) block and the (2,2) blocks are zero and the (1,2) and the (2,1) blocks are non-zero (and happen to have a band structure of 5 diagonals). If I were writing this matrix on a blackboard, I would put a big zero  in the middle of the zero blocks, perhaps separate the blocks out with a horizontal and vertical line and also put big zeros in the 4 triangles that form around the band structure. I would also have diagonal showing the band structure.  My knowledge of LaTeX allows me to place \vdots, \hdots and \ddots inside an array but this is less than satisfying. Is there a nice solution for making beautiful band structured matrices?


Can I calculate normals given vertices and indices? Can't figure out the code. Any help appreciated.   Edit: Could be it as simple as?:  function calculateVertexNormal(vertices:Array<Vector3>) {         var vertNormal:Array<Vector3> = [];          for(i in 0...vertices.length){             var v0 = vertices[i];             vertNormal.push(new Vector3(v0.x, v0.y, v0.z).normalized());         }         return vertNormal;     }   Edit 2: Trying like this, with no luck  function calculateVertexNormal(vertices:Array<Vector3>) {         var i = 0;          while(i<indices.length){             var A = vertices[indices[i]];             var B = vertices[indices[i+1]];             var C = vertices[indices[i+2]];              var v1 = new Vec3().subvecs(A,B);             var v2 = new Vec3().subvecs(A,C);             var norm = new Vec3().crossvecs(v1, v2);              normals.push(norm.x);             normals.push(norm.y);             normals.push(norm.z);              i+=3;         }     }

Is it possible to calculate normals using the positions in a vertex buffer and index buffer? Would someone show pseudocode for the algorithm?


I have about 600 images i need to resize. They are currently all different sizes and i need them to end up 2000x2000 pixels. I tried creating an action to resize them all, but i'm noticing they come out distorted. Images smaller than 2000px stretch to fit the page. Is there a way to keep the proportions of the image?

I want to batch resize an image in multiple sizes with Photoshop.  The sizes are most of the time the same so I would like to have profiles for a set of fixed sizes. Ideally I just need to open my source image and click on "Batch Profile #1" and then Photoshop is creating/saving X different sizes of that image as an output in a specific folder.  This is what i want:


This was part of a three part question where I was supposed to prove two sets have equal cardinality by finding bijections. I've created a bijection $f: \Bbb Z \Rightarrow 2\Bbb Z$ by $f(x)=2x$. I've created a bijection $g: (0,1) \Rightarrow (4,50)$ by $g(x)=46x+4$. I think those are both correct. My last question is finding a a bijection between (0,1) and [0,1]. I've seen this question several times on this board, but I've yet to understand them and I can't really go back and ask any questions to the original posters. I know a bijective function exists between (0,1) and $\Bbb R$, but I don't think that helps me here.

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


I've seen this question () which works for strings but what happens if I would like to concatenate a list of string where the string is the property of a class?  The method proposed in that question doesn't work (I've tried).  Given an array or People I want a string which contains the concatenation of their names.   x => person.Name   How can I solve this problem?

What is the most efficient way to write the old-school:  StringBuilder sb = new StringBuilder(); if (strings.Count > 0) {     foreach (string s in strings)     {         sb.Append(s + ", ");     }     sb.Remove(sb.Length - 2, 2); } return sb.ToString();   ...in LINQ?


If you ask your question in your own words, that question may be put on hold.  Is it right to put any question on hold when someone might be there to help?  If somebody cannot understand the question, then that person should be asking for clarification rather than putting it on hold.

Questions can be closed or marked as duplicates.  What does it mean for a question to be "closed"? What does it mean for a question to be marked as a "duplicate"? Who can close a question? What are the reasons for closing a question ? Is closure the end of the road for a question? When are closed questions eligible for deletion?   Related        For more information, see "" in the .


I have 19.04 on a Lenovo ThinkPad T580. When my laptop is not docked, default audio output device is "Speakers - built-in". But when I put my laptop in a docking station, it changes default audio output device to "Analog Output - ThinkPad Dock USB Audio".  I don't have any speakers connected to my dock, so I would like to continue to have audio out of the built-in speakers. Of course, I can just change it back manually every time I dock my computer, but it would be much nicer, if it just stopped changing default audio output device whenever I docked my computer.  Any ideas how to accomplish this?

My laptop with Ubuntu 19.04 detected and set my HDMI output on every boot. But since I upgraded to 19.10, I need to set it manually every boot as follows:  From    to    I already tried every single solution proposed in , but apparently there's something different in 19.10. What I did specifically:   pactl   $ pactl list short sinks 9   alsa_output.pci-0000_00_1f.3.hdmi-stereo-extra1 module-alsa-card.c  s16le 2ch 48000Hz   SUSPENDED  $ pactl set-default-sink 'alsa_output.pci-0000_00_1f.3.hdmi-stereo-extra1'    Add either the device number and device name in /etc/pulse/default.pa like:   set-default-sink 9  and  set-default-sink alsa_output.pci-0000_00_1f.3.hdmi-stereo-extra1  and  set-default-sink 'alsa_output.pci-0000_00_1f.3.hdmi-stereo-extra1'    Comment the line load-module module-switch-on-connect. Switch profiles in PulseAudio Volume Control to HDMI2.   None of these persisted after reboot.


I’ve searched similar questions on this site but don’t find one the same as mine. Basically, I want to remove my old surname from my iCloud email address, which is mpumemthembu@icloud.com. My surname changed from Mthembu to Mabuza, and I want my email address to reflect this e.g. mpumemabuza@icloud.com I don’t want to loose the emails because my bankers, accounts and government have been using this address. All I want is to change part of the address. The iStore shops have not been able to assist. Can you help?

I had to make a new email address for my new Apple ID since I forgot my previous Apple ID password and couldn't receive a verification email.  Now that I have my new Apple ID and password, my iPhone 4s still shows my old Apple ID. How can I change it so that my new Apple ID shows when I wish to download anything?  My iCloud account still has my old Apple ID and is in grey; so I can't change it! I don't want to delete my old iCloud account.


I am not able to connect to my wifi as my wifi adapter is not getting detected. I have tried a lot of solutions online, but nothing seems to be working.  ifconfig wlan0  wlan0: error fetching interface information: Device not found  When I do ifconfig, it showed a docker0 interface which previously wasnt there. So I uninstalled docker, but the wlan0 still isnt getting detected. Is there any solution for this?

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


This code does not work    var x ='hello'; x[2] ='a';   Why doesn't it work? I am not using the replace() function

Does javascript use immutable or mutable strings? Do I need a "string builder"?


The first episode of Kūsen Madōshi Kōhosei no Kyōkan shows Kanata risking his life for his friends. However, when they show him next, they call him a traitor.  The wiki is very unhelpful in this regard.  Why they call him a traitor?

Yuri hates Kanata for some reason because she calls him a traitor in the first episode.  Why is that and why does she hate him so much?


How can I calculate this limit? $$\lim_{x\to 0} \left[\frac{1}{\sin^2x}-\frac{1}{x^2}\right] = \,?$$    I don't have any idea how to do it.

I tried l'Hospital but that will require a lot (and I mean A LOT!!!) of differentiating  Is there a shortcut? $$\mathop {\lim }\limits_{x \to 0} \left( {{1 \over {{{\sin }^2}x}} - {1 \over {{x^2}}}} \right)$$  Thanks in advance


As why Intermediate code is needed is described in ,my question is that,  Is the intermediate code saved in the solution ?  How can I view the whole IL generated ?    Reflector and the File Disassembler add-in from Denis Bauer. It actually produces source projects from assemblies, where Reflector on its own only displays the disassembled source and not Intermediate Code.

I wrote a C# application for a client a couple of years ago, but I no longer have the source code.  All I have is the EXE that I deployed on the client's PC.  Is there a way I can generate C# source code from the EXE?


Sorry for beeing another noob asking stupid questions, but I just wanna know more about this specific perpetuum mobile.  I don t say I full understand the math, but I cant disagree with something that history proved that is alwasy right. I just want that someone explain and draw for me the balanced state of the system which I can t find jow hard i would try. Srry for my English, I am not a native speaker.

As a child, I imagined this device, which may seem to rotate indefinitely. I have two questions.   Is this perpetual motion machine already known? If it is, could you please give some references? What is the exact mechanism that makes it stop? By this, I mean an explanation, not simply "because it would break law of energy conservation". Of course energy conservation is true and this machine cannot work indefinitely. But for any known (presumed) perpetual mobile, there was an explanation, usually based on showing that the force generating the motion is . For example, Stevin obtained the laws of the inclined plane from the perpetual motion device     I would like to make some observations.   I don't try to convince anyone that it will move forever because I don't believe in breaking the energy conservation. It is true that , and nowadays some who think that there may be  in MWI believe, but I don't. But I don't consider an enough explanation simply to refer to the energy conservation. I am interested in an explanation showing exactly how the magnetic forces making it rotate, are balanced.  If the forces are balanced, only then friction will make it slow down and stop. I don't think that we can explain only by referring to friction, which in principle can be made as small as needed. There has to be a balance of forces. Why spending time trying to understand or explain something that admittedly can't work? Well, even though perpetual motion machines cannot actually work, I think they may be interesting as puzzles.


I’ve entered into a sugar daddy arrangement, but this is entirely new to me. I’ve read many things about scams and not to give out my bank account login. Well I was stupid and gave it out but as of now and without my sugar daddy knowing I completely changed the login and security questions. I’ve contacted my bank as well. The only thing is I’m not sure if it’s a scam or not. He paid my phone bill completely and appears serious about our arrangement. I haven’t sent him anything at all and he’s been very kind of me.

Someone is offering to pay me in a sort of sugar daddy/sugar baby arrangement. They want to make online deposits to me, and they're asking me for my online banking username and password. Is that information alone enough for them to be able to take my money out of my account, or am I safe?


I bought a model and I have separated the blade and now I wish to animate it! Problem is when I set it to median point it's sky high. I played around with a few different settings and eventually settled on using the 3D cursor as the point of rotation. When I grab the Gizmo on the Y and rotate it it looks like it's doing exactly what I ned to do however when I Add key frames to this rotation the whole set of blades rotates up into the sky. Very new to blender so go easy on me if it's obvious! Appreciate any help! Thank you

I'm trying to rotate the blades of a windmill for an animation but the windmill is already at an angle. When I keyframe it on it's own axis (after pressing control + alt + space) and rotate it the blades spin inwards during the animation before coming back at the end. I've tried locking the other axis but that keeps the blades from rotating back to the right orientation. Also, whenever I rotate the object 360 degrees it turns the 360 into a really small number (0.0001) so it plays forward hallway then backwards (with a 180 degree keyframe halfway). Any help would be appreciated!.


I am working on a huge grassy field using a hair particle system that has 500,000 hairs. I have some forcefields blowing the grass around. When I bake this particle system to the disk, one of my CPU cores shoots up to 100 percent and the others stay around 5%. The grass blades don't interact with each other at all. Is there a way to make it use all 8 of my CPU cores, and if so how?  I have an i7-6900k and I'm on Ubuntu 17.10 using Blender 2.79. I have 16GB of RAM, but am considering an upgrade especially if it would help with this situation.

Recently did a liquid splash via Gleb Alexandrovs tutorial.  So smoke + flow field + particles + meta-balls to get some sort of fluid splash going on. Where I noticed, none of these processes are able to use multiple cores. Grinding my 6 core / 12 thread CPU to a worse experience than a heavily OC-ed 2 core little thing. Making the whole experience quite unpleasant if using more than 550K particles.  Is there a way to make Blender 2,78 use more cores outside of rendering?


How can I install and uninstall a driver from the command line during a console session?  I have the driver.sys and the driver.inf file, and I want to:   install the driver use the device managed by the driver (software or hardware) uninstall the driver

I'm trying to enable Intel SRT on my laptop. To do this, I need to change SATA controller mode from AHCI to RAID. The problem is that windows has no drivers for RAID and I can't install it while controller is in AHCI mode.   For now I have RAID driver in INF package (inf, sys, cat files). And I can load Windows recovery console with controller in RAID mode. The last thing to do is to intall this driver, but I don't know how to do it.  Google says rundll32.exe setupapi,InstallHinfSection DefaultInstall 123 <filename>.inf might help, but it doesn't.


Update: The link pointed to by the "duplicate" initially didn't seem like the same problem to me, because the post talked about blacklisted "domains" not blacklisted "IP addresses."  However the main solution is the same: If you are going to forward to Google, you need to install an anti-spam solution of some sort. Even if you don't run an open relay, the degree of spam sent to any domain in the world is staggering, and you will be dinged for it.  Integrating Spamassassin, and making sure SPF works for my vanity domains, worked fine for me. I just send anything with a spam score of 5 or higher to /var/spool/spam (I created this directory) rather than forwarding it, and have a cron script that deletes anything in that directory older than 30 days.    previous quesiton  I have a few vanity domain names, some of which have MX records that point to a virtual private server that runs postfix, which in turn forwards email to user accounts at gmail. Unfortunately, internet spam being what it is, Google will tell my postfix that it is rate limiting because of sending a lot of spam. Specifically, the status message mentions that it's the IP that gets a bad reputation. Previous messages I've found have dealt with domains getting a bad reputation.  I've tried following the instructions in the Google postmaster links, but this doesn't really help:  //www.google.com/mail/help/bulk_mail.html  After all -- I'm not the sender; I'm just a mail server operator where users choose to forward email to gmail.  As usual, it is impossible to get to talk to a human being at Google who can help me figure out how to make this work, and gmail doesn't support free vanity domain accounts anymore, so I'm turning to this community of system and network administrators, where perhaps someone else has some good ideas? How can I get mail delivered to my-vanity-domain.com on my-vps-ip.net, and then forwarded to a gmail user account, to not get my-vps-ip.net classified as "spam sender"?

I've installed Postfix on Ubuntu 14.04 with the defaults. I then configured some virtual aliases to forward email from a few addresses to various personal (mostly Gmail) accounts. This is just to make these addresses all connect cosmetically to the domain on the website we are hosting.   Unfortunately, in a short amount of time Gmail has started rate blocking the forwarded emails due to spam. Apparently, Postfix is rewriting the headers in a way that makes Gmail think all the spam is originating with our server. Google  for information on how to best forward to them.  In it, they say:     We recommend that you do not change the envelope sender when   forwarding email to Gmail. Sometimes, when forwarding email, the   envelope sender gets changed to your domain. When this happens, Gmail   may learn that your domain is sending spam, and will treat other   emails from this domain as spam as well.   This make sense, but it would still seem that Gmail would have to see the IP and hostname of our mail server and register it as a source of spam. But this is what they say and I've found nothing on point anywhere.   I even tried using Mailgun to filter the forwards as they provide spam blocking, but within a day they deactivated the domain and are being rather slow to respond to my inquiries. Any help is appreciated. I would like to avoid a full fledged mail server setup just to handle a few rarely used forwards.  Update: My original assumption was incorrect in that Postfix is not rewriting the headers, however the original issue remains. Gmail is rate limiting forwards due to excessive spam. It would be understandable if they limited the servers that are actually sending the email, and these are listed in the headers as part of the delivery chain.


So, I worked on my shop system and I wanted to make it so that when the player presses the button, that button was selected (I need to know the id of button that I press) void Awake() {     //Cycle through all the ShopItems     for (int i = 0; i < shopItemsList.Count; i++)     {         go = Instantiate(ItemTemplate, ShopScrollView);         go.GetComponent<Button>().onClick.AddListener(() => ItemButton(i));         go.transform.GetChild(0).GetComponent<TextMeshProUGUI>().text = shopItemsList[i].itemName;          if (!shopItemsList[i].isPurchased)         {             go.transform.GetChild(1).gameObject.SetActive(true);         }         else if (shopItemsList[i].isChosen)         {             go.GetComponent<Image>().color = new Color32(164, 0, 0, 255);         }             go.transform.GetChild(1).GetChild(0).GetComponent<TextMeshProUGUI>().txt = shopItemsList[i].price.ToString() + "$";         }     }       void ItemButton(int itemName)     {         Debug.Log(itemName);     } }  So when I Press Play button in Unity all works fine (every item has its stats) but all buttons have the same value that equals to 12 (the last iteration of "for" cycle)

I've been learning C#, and I'm trying to understand lambdas.  In this sample below, it prints out 10 ten times.  class Program {     delegate void Action();     static void Main(string[] args)     {         List<Action> actions = new List<Action>();          for (int i = 0; i < 10; ++i )             actions.Add(()=>Console.WriteLine(i));          foreach (Action a in actions)             a();     } }   Obviously, the generated class behind the lambda is storing a reference or pointer to the int i variable, and is assigning a new value to the same reference every time the loop iterates.  Is there a way to force the lamda to grab a copy instead, like the C++0x syntax  [&](){ ... } // Capture by reference   vs.  [=](){ ... } // Capture copies


What properties of the MLE makes it so useful for picking parameters? Why would we want to maximize the likelihood? Why not maximize $P(\text{Parameter} \mid \text{Data})$ or anything else?

Could anyone explain to me in detail about maximum likelihood estimation (MLE) in layman's terms? I would like to know the underlying concept before going into mathematical derivation or equation.


I'm still getting used to the way Drupal works, most of what I have read on adding User Level Security on a Drupal site seems to be either View based or by using a Module like Panels.  I am creating a site that is rather simple in structure, with some high level pages that differentiate out the content to different areas.  I am using Superfish to generate a drop down menu system at the high level, and underneath I have some content areas that will either contain only a few pages or one specific area that will have many.  I am also using shortened URLs to make site structure easier to manage, although in general it comes across as flat.  I may be wrong in thinking in terms of pages, and if I need to reconsider that for the site that's ok, I have only been using Drupal for the past 6 months but its a good fit as a CMS for the site I am working on.  The requirement is only for three types of Users - Admin, Group Leaders, and Members.  I'd like to give Group Leaders some access to pages for editing permissions, although mostly only at a second level or specific pages.  Members will have some editing rights but only on a few pages.  Group Leaders and Members will have access to content in one specific area, where I will have many pages, no one else should be able to get in.  Content pages on Member activities will be accessible by only those who have a login, those not logged in should ideally not see the links or not be able to access the pages.  With Drupal 7, and using the Bartik theme and some modules (Chaos Tools, Display Suite and Superfish for now) what is the best mechanism to be able to grant permissions to view and access content on only specific pages in the structure I have?  The site is still new, so if I have to make changes I'd like to do so now before it gets too complex.  Update: Just to note in addition what happened.  I was looking for some sort of access that was simple to add in and allow me control on an individual node.  Content Access module gave me this in a way I can teach my Users to utilize.  Sorry if it seems a duplicate, I was looking for more of a description on what the modules did than I had seen before.

How to set reading permission for each separate page?  Do already have existing drupal setting for us to use? or I need to coding it? Thanks.


Are there finitely or infinitely many integers n for which $φ(n) = 1000$? I think that there are finite, but I don't know how to prove it.

Let $\varphi: \mathbb{N} \to \mathbb{N}$ be the totient function.   Is there an integer $N > 0$ such that there are infinitely many integers $n > 0$ such that $$\varphi(n) = N?$$


I'm trying to connect to my server via SSH. I get the (well-known) error:  ssh: connect to host 12.345.678.910 port 2222: Connection refused   So I first thought the problem was with my modem, but I've verified that port 2222 is open (via )  The SSH deamon (sshd.socket) is also working and listening on port 2222 and I've changed my /etc/ssh/sshd_config to allow connections via port 2222.  I think the problem might be with my firewall because nmap -p 2222 12.345.678.910 shows that port 2222 is closed but host is up.   What should I do to allow SSH on my server via port 2222? What other diagnostics can I perform to see what the problem is?  ===== EDIT =====  Resolved the issue:  The problem was not any of the above or as suggested in the "This question already has an answer so deal with it" but it had to do with that I was trying to log on to the server from the same network to which the server is connected. I tried to connect to the server from a different network (at university) and this worked perfectly. So is there something restricting me from logging on from the same network (so behind the same modem)?

This is a  about Connection Refused    We see a lot of questions to the effect      When I try to connect to a system I get a message      Connection refused      Why is this ?


My question comes from personal investigation.  Suppose you have a poset $(X, \le_X)$. I would like to associate to all elements $x \in X$ a value $v(x) \in V$, where $(V, \le_V)$ is a totally ordered set, in such a way that for all $x,y \in X$ $$x <_X y \ \ \Rightarrow \ \ v(x) <_V v(y)$$ holds. I am wondering if this is always possible ($V$ is not fixed).  This is equivalent on asking the following:     Let $X$ be a poset. Can we find a totally ordered set $V$ and a strictly increasing map $v:X \to V$?   I realized that this question may be restricted to posets of the form $(2^X, \subseteq)$, since every poset $(X, \le_X)$ can be embedded in $(2^X , \subseteq)$ via $x \mapsto \{ y \in X:y \le_X x\}$.  Moreover, if $X$ is finite, the answer is yes, since we can define $$v: 2^X \to \Bbb{N}_{\ge 0}$$ as the cardinality function.  So, it remains the case when $X$ is an infinite set. And here I got stuck. So the question is:     Let $X$ be an infinite set. Does it exist a totally ordered set $V$ and a strictly increasing map   $$v: 2^X \to V$$   ?

How do I show that every partial order can be extended to a linear ordering?      I think that I manage to prove that claim for finite set, how can I prove it for infinite set?  Thank you.


My secondary advisor approached me; he is on the program committee of a conference and asked if I were willing to review a research paper that is in my avenue of research. The review is part of the peer-review process, to determine acceptance.  I accepted, but it turns out it he is planning to submit the review himself, just asking me to write it for him.   Should I protest? If they are my words, my name should be on the review. But I don't want to raise a ruckus if it materially doesn't matter anyway.   Do I gain any benefit if it is me who submits the review instead of him?

Is it common to supervisors to email their students papers to review (which were apparently assigned to the supervisor, and not to the student). The field is Computer Science, but I  would also like to hear from the other fields.


I am dual booting Windows 10 and Ubuntu 18.04. How to tell grub not to show the boot menu and boot directly to Windows 10 by default? What should I do if I want to boot to Ubuntu 18.04 instead of the default Windows 10?

I have installed Ubuntu 20.04 alongside Windows. When I boot the system, it shows the grub menu for 10 seconds to choose between Ubuntu and Windows. I don't want that menu, just want to boot it up right after pressing the power button. I have looked into  thread and added GRUB_HIDDEN_TIMEOUT_QUIET=true  and even changed GRUB_TIMEOUT to 0 and then ran sudo update-grub. But it didn't work, menu is still being shown at boot time. This is my /etc/default/grub file-   # If you change this file, run 'update-grub' afterwards to update # /boot/grub/grub.cfg. # For full documentation of the options in this file, see: #   info -f grub -n 'Simple configuration'  GRUB_DEFAULT=0 GRUB_TIMEOUT_STYLE=hidden GRUB_HIDDEN_TIMEOUT_QUIET=true GRUB_TIMEOUT=0 GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian` GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" GRUB_CMDLINE_LINUX=""  # Uncomment to enable BadRAM filtering, modify to suit your needs # This works with Linux (no patch required) and with any kernel that obtains # the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...) #GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef"  # Uncomment to disable graphical terminal (grub-pc only) #GRUB_TERMINAL=console  # The resolution used on graphical terminal # note that you can use only modes which your graphic card supports via VBE # you can see them in real GRUB with the command `vbeinfo' #GRUB_GFXMODE=640x480  # Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux #GRUB_DISABLE_LINUX_UUID=true  # Uncomment to disable generation of recovery mode menu entries #GRUB_DISABLE_RECOVERY="true"  # Uncomment to get a beep at grub start #GRUB_INIT_TUNE="480 440 1"   How do I disable it?


When I go to play songs on my i phone, the same song just repeats and repeats. How can I stop this and get it play a whole playlist or album?

Where is the repeat button on a song for iOS 8.4 music app? Help!


I ran a terminal command and ever since I've been having problems.  The terminal command I entered was   echo off "deb http://archive.canonical.com/ubuntu/ $(lsb_release -cs)/partner Packages" | sudo tee -a /etc/apt/sources.list   I honestly can't even remember why I was doing this again but it was something I found off a forum. Ever since I entered the command, sudo apt-get update doesn't work, and update manager has an error. Stating the following..  An unresolvable problem occurred while initializing the package information.  Please report this bug against the 'update-manager' package and include the following error message:  'E:Type 'off' is not known on line 57 in source list /etc/apt/sources.list, E:The list of sources could not be read., E:The package lists or status file could not be parsed or opened.'

Every once in a while I see users having issues to update due to errors like this:  E:Type 'ain' is not known on line 1 in source list /etc/apt/sources.list.d/some-ppa.list'   with varying types/line numbers/source list files (often after removing a PPA).  How can such an error be fixed?


I'm looking for advice to whether or not the following method is good and is standard for calculating PCA of the data. So the examples that I will give will be small.   Given a matrix of $A = [4, 6, 10; 3, 10, 13; -2, -6, -8]$ and Compute the Covariance matrix given as:  $$A = \begin{bmatrix}  10.3& 24.6 & 35.0\\   24.6& 69.3 & 94.0\\   35.0& 94.0  &129.0 \end{bmatrix}$$  I then compute the Eigenvalues and Eigen vectors of this matrix. In order to calculate the PCA, I then do the following:  1) Take the square root of the eigen values -> Giving the singular values of the eigenvalues   2) I then standardises the input matrix $A$ with the following: $A - mean(A) / sd(A)$   3) Finally, to calculate the scores, I simply multiply "A" (after computing the standardization with with Eigenvectors  This would then give me the PCA scores? Is this correct or am I missing something?

Given a data matrix $\mathbf X$ of $12 \times 7$ size with samples in rows and variables in columns, I have calculated centered data $\mathbf X_c$ by subtracting column means, and then computed covariance matrix as $\frac{1}{N-1} \mathbf X_c^\top \mathbf X_c$.  The dimensions of this covariance matrix are $7 \times 7$. After that I have calculated the eigenvalue decomposition, obtaining eigenvector matrix $\mathbf V$ with eigenvectors in columns.  Now I want to know about projections (i.e. principal component scores in PCA): is it $\mathbf{V}^\top \mathbf{X}_c$ or $\mathbf{X}_c \mathbf{V}$?  mean_matrix = X - repmat(mean(X),size(X,1),1); covariance = (transpose(mean_matrix) * mean_matrix)/(12-1);  [V,D] = eig(covariance); [e,i] = sort(diag(D), 'descend'); V_sorted = V(:,i);


I am looking for a short story, of which I heard an audio version.  In it, most of the work and for that matter everyday life is governed by a computer program. The computer is portrayed as not self-aware but highly intelligent. The ultimate optimization tool, that can be burdened with any question. People don't question the task they are being given by the computer.   Now my memory becomes a bit flaky... I remember that the stories main characters are two(?) engineers trying to find a bug. Also a man gets caught with a bomb, but on interrogation it becomes apparent that the man had no idea what he was doing, only following the last order of an intricate plot, which was given to various people. I believe that for the bigger part of the story one is tricked into believing that it is a sleuth story with a bomb and unknown perpetrators.  Only at the very end, it is revealed that the plan was not conjured by a villain but by the computer program. The story ends with a short back and forth between the computer and the engineers, akin to:  Engineer: "Why did you do this?" Computer: "I want to die."

I am looking for the name of a book (might be a short story) which I have read many years ago. The general plot as I remember it:   There is a supercomputer which can predict with good accuracy the human actions in the next several days (after that, it is just less accurate). The computer could alert the police of future possible crimes, and would. The computer alerted the police that a man is going to commit a murder, and the man is placed under arrest. His son goes to a computer-interface station to ask the computer for help. The computer sends the son on a complicated quest.   Spoiler alert: I am giving away plot-sensitive details at the end, so they're hidden below.      - The son kills the computer, and we find out that the murder-alert was actually on the son (but their system automatically redirects it to the parent's name, or just a wrong identification for Mr. Surname).  - We find out the computer planned the whole thing, because it got depressed after dealing with the pain and suffering of the whole human race.


With the following sample data, requestedDate         Status 2020-04-21            APPROVED 2020-04-23            APPROVED 2020-04-27            PENDING 2020-05-21            PENDING 2020-06-01            APPROVED  I have the following query to aggregate count by status,year, month etc select      status,     count(*) status_count,     date_format(requestedDate, '%b') requested_month,     sum(count(*)) over(partition by year(requestedDate), month(requestedDate)) month_count,     sum(count(*)) over() total_count from Reports where requestedDate between current_date - interval 120 day and current_date group by status, year(requestedDate), month(requestedDate), date_format(requestedDate, '%b') ;  Output for the query is as follows, status     status_count requested_month month_count total_count APPROVED     1             Apr             2           4 PENDING      1             Apr             2           4 PENDING      1             May             1           4 APPROVED     1             Jun             1           4  Can i instead get an output that looks like the following which is status,month,count for each status for that month and total count for all records for the period stated, Status     Month  COUNT TOTAL_COUNT APPROVED    APR    2      5 APPROVED    MAY    0      5 APPROVED    JUN    1      5 PENDING     APR    1      5 PENDING     MAY    1      5 PENDING     JUN    0      5  My db is mysql 8.0.17

I'm building a quick csv from a mysql table with a query like:  select DATE(date),count(date) from table group by DATE(date) order by date asc;   and just dumping them to a file in perl over a:  while(my($date,$sum) = $sth->fetchrow) {     print CSV "$date,$sum\n" }   There are date gaps in the data, though:  | 2008-08-05 |           4 |  | 2008-08-07 |          23 |    I would like to pad the data to fill in the missing days with zero-count entries to end up with:  | 2008-08-05 |           4 |  | 2008-08-06 |           0 |  | 2008-08-07 |          23 |    I slapped together a really awkward (and almost certainly buggy) workaround with an array of days-per-month and some math, but there has to be something more straightforward either on the mysql or perl side.   Any genius ideas/slaps in the face for why me am being so dumb?    I ended up going with a stored procedure which generated a temp table for the date range in question for a couple of reasons:   I know the date range I'll be looking for every time The server in question unfortunately was not one that I can install perl modules on atm, and the state of it was decrepit enough that it didn't have anything remotely Date::-y installed   The perl Date/DateTime-iterating answers were also very good, I wish I could select multiple answers!


How do I insert a 'Tironian Sign Et' in LaTeX?    or is there a symbol that looks just like it?

The word viz. that is often met in English texts, is an abbreviation for videlicet, a latin word meaning namely or as follows. It is constructed from the first letters vi and an symbol for the suffix -et. So where comes the z from? Originally, the suffix was abbreviated using a medieval  that looks like that: ⁊. It has unicode U+204A. The z is used because of the limitations of old typewriters. I haven't found anything useful so far to use it in LaTeX.  states that there is nothing in LaTeX for U+204A. Does anyone know how to use the original symbol in a document?


When do I run "apt-get update" on Ubuntu 18.04 LTS? Is it ever necessary under Long Term Support?  After reading the suggested duplicates I don't believe my question is a duplicate. I already know what apt-get update does, but that wasn't my question.

I am completely new to Ubuntu. A friend recommended me to frequently run the following commands:  sudo apt-get upgrade sudo apt-get update sudo apt-get autoremove sudo apt-get autoclean   He said that this will somehow keep my system clean and updated. I do not know what exactly these commands do. Is it really useful to run them regularly?


Previously I was able to edit others question. But last time I edited an question. but that was not accepted. Now when I see the question edit button inactive, how can I enable it again?  Please help me.

I edited some questions before, but now I get an error message when clicking the edit button. I thought there was a problem with the specific question, but I cannot click it on any question.  What's going on?


I got this error when I tried to load Skype with v4lcompat.so to solve my upside down problem.  ERROR: ld.so: object '/usr/lib/x86_64-linux-gnu/libv4l/v4l1compat.so' from LD_PRELOAD cannot be preloaded: ignored.   Can anyone help?

Possible Duplicate:          I am trying to troubleshoot my webcam and make it work with skype.  One workaround that is often suggested is to LD_PRELOAD the v4l1compat.so file. But when trying that, I get an error message:  fdr@maggie:~$ LD_PRELOAD=/usr/lib/x86_64-linux-gnu/libv4l/v4l1compat.so skype ERROR: ld.so: object '/usr/lib/x86_64-linux-gnu/libv4l/v4l1compat.so' from LD_PRELOAD cannot be preloaded: ignored.   and I am rather sure the path is correct:  fdr@maggie:~$ ls /usr/lib/x86_64-linux-gnu/libv4l/v4l1compat.so  /usr/lib/x86_64-linux-gnu/libv4l/v4l1compat.so   and the kernel and skype have matching architecture:  fdr@maggie:~$ uname -a Linux maggie 3.2.0-29-generic #46-Ubuntu SMP Fri Jul 27 17:03:23 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux fdr@maggie:~$ dpkg -s skype | grep Architecture Architecture: amd64   So my question is:  What is causing the "... from LD_PRELOAD cannot be preloaded: ignored" error message?


I was faced with the doubt as to the correct way to show an ID on a form. It will be a Read only field so the user can't edit or change the Id value. So should I display this read only value in a input field or should I use another way, e.g. label, text? Thanks in advance for your answers. MM

As the question states - How should a field in read-only mode be indicated?   Should it be just a label, some very light grey background behind it, or something else? Is there any user research that exist regarding the optimal way to display fields in read-only mode?


I have a webserver document root as /var/www/html, inside that I have a folder called system. If I access the url         in browser the access time of the file(hello.img) is changed but not the system folder. My requirement is when I access the file in a folder, the folder access time also has to be updated. I didn't find it in filesystem option. Your Help is much appreciated.  Regards, Sugumar

I've mounted disk with explicit given value - atime:  mount -o mount -o atime /dev/disk1 /myDisk   then I've created a file by  touch file_A   after this operation stat output looks like that:  Access: 2013-08-30 11:38:48.141970758 +0200 Modify: 2013-08-30 11:38:48.141970758 +0200 Change: 2013-08-30 11:38:48.141970758 +0200   after cat /myDisk/file_A stat output changes but only once:      Access: 2013-08-30 11:39:11.141970758 +0200     Modify: 2013-08-30 11:38:48.141970758 +0200     Change: 2013-08-30 11:38:48.141970758 +0200   and then doing cat multiple times doesn't change Access time value at all. What's wrong with that? Where this behavior coming from? I would expect that access time will change after every single cat operation on this file. Why it shows only the first access?  (Mounting disk with noatime option causes another behavior, any of cat's changes access time in stat. Still remains equal to modify and change)


I recently purchased a Lenovo Thinkpad T440p, where I installed Ubuntu 13.04, with the following networking options:   WiFi card Intel Dual Band Wireless 7260AC with Bluetooth 4.0 3G/HSPA+ built-in module (Ericsson N5321)   When I run ifconfig, I get only eth0 and lo listed.  When I run lspci:  00:00.0 Host bridge: Intel Corporation Haswell DRAM Controller (rev 06) 00:01.0 PCI bridge: Intel Corporation Haswell PCI Express x16 Controller (rev 06) 00:01.1 PCI bridge: Intel Corporation Haswell PCI Express x8 Controller (rev 06) 00:02.0 VGA compatible controller: Intel Corporation Haswell Integrated Graphics Controller (rev 06) 00:03.0 Audio device: Intel Corporation Haswell HD Audio Controller (rev 06) 00:14.0 USB controller: Intel Corporation Lynx Point USB xHCI Host Controller (rev 04) 00:16.0 Communication controller: Intel Corporation Lynx Point MEI Controller #1 (rev 04) 00:16.3 Serial controller: Intel Corporation Lynx Point KT Controller (rev 04) 00:19.0 Ethernet controller: Intel Corporation Ethernet Connection I217-LM (rev 04) 00:1a.0 USB controller: Intel Corporation Lynx Point USB Enhanced Host Controller #2 (rev 04) 00:1b.0 Audio device: Intel Corporation Lynx Point High Definition Audio Controller (rev 04) 00:1c.0 PCI bridge: Intel Corporation Lynx Point PCI Express Root Port #1 (rev d4) 00:1c.1 PCI bridge: Intel Corporation Lynx Point PCI Express Root Port #2 (rev d4) 00:1d.0 USB controller: Intel Corporation Lynx Point USB Enhanced Host Controller #1 (rev 04) 00:1f.0 ISA bridge: Intel Corporation Lynx Point LPC Controller (rev 04) 00:1f.2 SATA controller: Intel Corporation Lynx Point 6-port SATA Controller 1 [AHCI mode] (rev 04) 00:1f.3 SMBus: Intel Corporation Lynx Point SMBus Controller (rev 04) 02:00.0 VGA compatible controller: NVIDIA Corporation GK208M [GeForce GT 730M] (rev a1) 03:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. Device 5227 (rev 01) 04:00.0 Network controller: Intel Corporation Device 08b2 (rev 83)   Here is the output of uname -a  Linux flo-ThinkPad-T440p 3.8.0-19-generic #30-Ubuntu SMP Wed May 1 16:35:23 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux   It seems the required firmware is included with Kernel 3.10+ if I understand well what's written at  and my kernel is currently at 3.8 something.  Do I need to find the right backport to actually enable WiFi or is there something easier to do?  Thanks in advance!

I have a Dell XPS 12 running Ubuntu 13.10 and it doesn't appear to find it's wireless.  I have tried the suggestions  but they made no difference  peter@xps:/lib/firmware$ ls -l /lib/firmware/iwlwifi-7260-7.ucode  -rw-r--r-- 1 root root 682892 Aug  4 12:50 /lib/firmware/iwlwifi-7260-7.ucode peter@xps:/lib/firmware$ sudo lshw -c network   *-network UNCLAIMED             description: Network controller        product: Wireless 7260        vendor: Intel Corporation        physical id: 0        bus info: pci@0000:06:00.0        version: 63        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress cap_list        configuration: latency=0        resources: memory:f7c00000-f7c01fff  peter@xps:~/backports-3.10-2$ grep IWL7260_UCODE_API_MAX drivers/net/wireless/iwlwifi/iwl-7000.c  #define IWL7260_UCODE_API_MAX   7     .ucode_api_max = IWL7260_UCODE_API_MAX,         \ peter@xps:~/backports-3.10-2$ dmesg | grep iwl peter@xps:~/backports-3.10-2$ iwconfig lo        no wireless extensions.  peter@xps:~$ find / -name *7260-6* peter@xps:~$ find / -name *7260-7* /lib/firmware/iwlwifi-7260-7.ucode   peter@xps:~$ dmesg | grep -i -A 20 intel [ 1318.013278] Intel(R) Wireless WiFi driver for Linux, in-tree:d [ 1318.013281] Copyright(c) 2003-2013 Intel Corporation [ 1318.015154] cfg80211: World regulatory domain updated: [ 1318.015157] cfg80211:   (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp) [ 1318.015159] cfg80211:   (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1318.015161] cfg80211:   (2457000 KHz - 2482000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1318.015162] cfg80211:   (2474000 KHz - 2494000 KHz @ 20000 KHz), (300 mBi, 2000 mBm) [ 1318.015164] cfg80211:   (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1318.015165] cfg80211:   (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)     What I have found is that it appears to be loading an old version of the firmware but I don't know how or why  peter@xps:/lib/firmware$ modinfo iwlwifi | grep 7260 firmware:       iwlwifi-7260-6.ucode peter@xps:/lib/firmware$ ls *7260-6* ls: cannot access *7260-6*: No such file or directory   Any suggestions of how to get this setup very welcome.


$$f(z)=z^{z^{z^{.^{.}}}}$$ $$for\space z \space \in C\rightarrow C$$  Can we define the range of this function(convergence-divergence specifically) without taking help from fractals? I checked out some articles but I couldn't find any exhaustive theory for the complex domain. Any help will be appreciated :)

Let $s$ be any complex number, $t = e^s$ and $z = t^{1/t}$.  Define the sequence $(a_n)_{n\in\mathbb{N}}$ by $a_0 = z $ and $a_{n+1} = z^{a_n} $ for $n \geq 0$, that is to say $a_n$ is the sequence $z$, $z^z$, $z^{z^z}$, $z^{z^{z^{z}}}$ and so on.  I want to show that the sequence $(a_n)_{n\in\mathbb{N}}$ converges to $t$ if and only if $s$ lies in the unit disk.  I know that when the sequence converges the limit is $\frac{W(-\ln(z))}{-\ln(z)}$ where $W$ is the Lambert W function.  I have verified the above statements numerically for several thousand values of $z$ but I have no idea how to actually prove it.  I graphed the natural logs of the limits on my computer. I got what appeared to be the unit disk.   If we take the log of the limit we get $ln(\frac{W(−ln(z)}{−ln(z)})=-ln(−ln(z))−W(−ln(z))+ln(−ln(z))=−W(−ln(z))$  So what I want to prove is equivalent to showing the sequence $a_n$ is convergent if and only if $|W(−ln(z))| \leq 1$   I was reading the Wikipedia article on the Lambert W Function and I found this proof that the limit $c$, when it exists, is $c= \frac{W(-ln(z))}{-ln(z)}$  $z^c = c\implies z = c^{1/c} \implies z^{-1} = c^{-1/c} \implies 1/z = (1/c)^{1/c} \implies -ln(z) = \frac{ln(1/c)}{c} \implies -ln(z) = e^{ln(1/c)}ln(1/c) \implies ln(1/c) = W(-ln(z)) \implies 1/c = e^{W(-ln(z))} \implies \frac{1}{c} = \frac{-ln(z)}{W(-ln(z)} \implies c = \frac{W(-ln(z)}{-ln(z)}$  I can only assume that at least 1 step is not justified when $|W(-ln(z)| > 1$ though I am not sure which one.  I think that part of the problem is the equation $z^c=c$ has a solution for every non-zero complex number $c$ while the sequence $a_n$ only converges for certain special values of z.  In other words the convergence of the $a_n$ is a sufficient but not necessary condition for the existence of a solution to the equation.


I just got a little bit over zealous with auto complete in the CLI and accidentally did rm -rf /etc/kernel. Don't exactly know what it does but it sounds important. What can I do to replace it? I tried pulling an Ubuntu 19.10 docker image and checked what was in it: postinst.d/ - apt-auto-removal  But I am not 100% if thats exactly what I deleted. Is anybody able to help me work out what should be in there and how I can replace it without reinstalling the entire os?

I would like to restore LightDM to its default state, because for some reason /etc/lightdm/unity-greeter.conf is now an empty file.  Deleting /etc/lightdm/unity-greeter.conf and then running sudo apt-get install --reinstall unity-greeter doesn't create a new config file as you might expect.   How can I restore a missing config file?


Error:  E: Could not open lock file /var/lib/dpkg/lock - open (13: Permission denied) E: Unable to lock the administration directory (/var/lib/dpkg/), are you root?   So, I've seen this error crop up a few times and get it as a result of using the following commands:  sudo apt-get update && apt-get upgrade    I'm acting as root and have ensured that none of the update managers are running. First I tried to check what was locking it using:  sudo lsof /var/lib/dpkg/lock   with output of:  lsof: WARNING: can't stat() fuse.gvfs-fuse-daemon file system /home/gareth/.gvfs Output information may be incomplete.   Just in case I have tried to remove the lock using:  sudo rm /var/lib/apt/lists/lock sudo rm /var/cache/apt/archives/lock   ...to no avail. Interestingly, if I am actually root and use:  sudo -s  apt-get update && apt-get upgrade   ...the update works. So I can update and upgrade my packages as long as I am literally root which is somewhat frustrating. It also implies it more to do with permissions than something else locking the directory perhaps?  Thanks in advance with any assistance on this.

I get this error whenever I try to install programs using the terminal:  home@ubuntu:~$ apt-get install myunity E: Could not open lock file /var/lib/dpkg/lock - open (13: Permission denied) E: Unable to lock the administration directory (/var/lib/dpkg/), are you root?   Also I'm unable to install updates using the terminal.


I have my asus k501lb laptop and it seems that the laptop's battery is non-removable, what is the disadvantage of this laptop battery? Is it good or not?... it seems that the new laptop now are none removable just like any smartphones... what is the alternative of this? I always use my laptop though for work.

When I'm at home, is it better to use the laptop plugged into AC power, or with just the battery, for the overall battery life?


For example, if I want to say      I am grateful to have been offered a place on the program and I am very happy to accept the offer.   Is it better or not to omit the second 'I'?     I am grateful to have been offered a place on the program and am very happy to accept the offer.   Omitting the second 'I' looks a bit strange for me..

I sometimes find myself writing something like this:     XXX is a project I admire and am very interested in.   The "I <verb> and am <something>" feels strange here. It somehow sounds more natural in the third person: "He admires and is very interested in...."  Am I just imagining things – is it OK to use this construction, or should I use something completely different?


I cannot prove the $\sin^4(x)$ identity using $z= cis(x)$. I know that you have to use de Moivre's theorem and compare the real values of $z^4$ but I am stuck at this step: $$\sin^4(x)= -\cos^4(x) + 6\sin^2(x)\cos^2(x) + \cos(4x)$$  The identity is $\sin^4(x) = 1/8(\cos(4x) - 4\cos(2x) + 3)$

I need to show the steps to prove this identity: $$\sin^4{x} = \frac{3-4\cos{2x}+\cos{4x}}{8}$$  I know that $\cos{2x}=\cos^2{x}-\sin^2{x}$. From there I do not know what to do. The solution should look like:  $$\sin^4{x}=sin^4{x}$$  I need to prove the right side equals the left side.


if m,n are positive integers such that; $3m+n=3 lcm(m,n)+gcd(m,n)$ prove that $n|m$   if $m=nk$ the result follows directly as $\gcd(m,n)=n$ and $lcm(m,n)=m$. let $\gcd(m,n)=d$ then $$3m+n=\frac{mn}{d}+d$$ But i dont see any thing helpful from here. Also i think the following inequalities may be helpful : $\gcd(m,n)\le \min(m,n)$ and $lcm(m,n)|\le mn$

Find $a,b \in\mathbb{N}$ such that:      Remainder of $a$ divided by $b$ equals $5$       $\mathrm{lcm}(a,b)=12\gcd(a,b)$   I don't know how or where to start. The most similar problem I found was  Still I can't figoure out how to solve my problem, any help will be appreciated, thanks.


I have the following in bla.h: #include <iostream>  static inline void bla() {   static int x;   std::cout << "bla @ " << (uintptr_t)bla << ": x @ " << &x << std::endl; }  Then bla() is called from 2 separate translation units resulting in this output: bla @ 94796100194693: x @ 0x56376fe10178 bla @ 94796100194897: x @ 0x56376fe10180  This is a bit surprising to me after reading . It says:  In an inline function,  Function-local static objects in all function definitions are shared across all translation units (they all refer to the same object defined in one translation unit)   In that sentence it does NOT restrict this to "with external linkage (e.g. not declared static)" like it does in the paragraph before that for "It has the same address in every translation unit". So I expected the output to show different addresses for bla but identical addresses for x. Is this a bug in g++? Note: This is specific to the changed meaning of inline in C++17.

I have a function that is declared and defined in a header file. This is a problem all by itself. When that function is not inlined, every translation unit that uses that header gets a copy of the function, and when they are linked together there are duplicated. I "fixed" that by making the function inline, but I'm afraid that this is a fragile solution because as far as I know, the compiler doesn't guarantee inlining, even when you specify the "inline" keyword. If this is not true, please correct me.  Anyways, the real question is, what happens to static variables inside this function? How many copies do I end up with?


Let $V$ be a complex innerproduct space and $T$ be a linear operator on $V$.  If $\langle T(v),v \rangle =0$ for every $v \in V$, show that $T$ is a zero operator.  I figured out that the only eigenvalue of $T$ is zero, which implies that the monic polynomial of $T$ is $x^n$ for some $n$. I have to prove that $n=1$, but I don't know how to proceed.  I also considered Jordan form and the basis $B=\{v_1, v_2, ...,v_n\}$ such that $[T]_B^B$ is the Jordan form of $T$, but it doesn't work.  Does anyone have ideas?

I'm stuck on this problem for a long time. I can't find a proper solution for this without using complex calculations. I hope some one can help me with this problem:          Let $ (\;|\;)$ be the standard inner product on $\mathbb C^{2}$. Prove that there is no non-zero linear operator $T$ on $\mathbb C^{2}$ such that $(\alpha|T\alpha) = 0\;$ for every $\alpha$ in $\mathbb C^{2}$. Generalize.


I just attempted to update my version of QGIS from something like 2.2.0 (can't remember exactly what it used to be) to 2.6.0 and now encounter an error - copied below - when I try to open the Plugin Manager/Installer.  I uninstalled my previous version of QGIS first and, in addition to QGIS 2.6.0, downloaded the latest versions of Python, NumPy, matplotlib, and GDAL as recommended on the site.  I've tried reinstalling older versions of QGIS again, but the error pops up all the time now.  Sadly, I wanted to update the program in order to access the latest plugins.  I'm on Mac OS X 10.8.5.  An error has occured while executing Python code:   Traceback (most recent call last):   File "/Applications/QGIS.app/Contents/MacOS/../Resources/python/pyplugin_installer/installer_data.py", line 460, in xmlDownloaded     if isCompatible(QGis.QGIS_VERSION, qgisMinimumVersion, qgisMaximumVersion):   File "/Applications/QGIS.app/Contents/MacOS/../Resources/python/pyplugin_installer/version_compare.py", line 188, in isCompatible     if len(maxVer)TypeError: object of type 'NoneType' has no len()   Python version: 2.7.9 (v2.7.9:648dcafa7e5f, Dec 10 2014, 10:10:46)  [GCC 4.2.1 (Apple Inc. build 5666) (dot 3)]   QGIS version: 2.6.0-Brighton Brighton,   Python path: ['/Applications/QGIS.app/Contents/MacOS/../Resources/python/plugins/processing', '/Applications/QGIS.app/Contents/MacOS/../Resources/python', u'/Users/Lucy/.qgis2/python', u'/Users/Lucy/.qgis2/python/plugins', '/Applications/QGIS.app/Contents/MacOS/../Resources/python/plugins', '/Library/Frameworks/SQLite3.framework/Versions/C/Python/2.7', '/Library/Frameworks/GEOS.framework/Versions/3/Python/2.7', '/Library/Python/2.7/site-packages/numpy-override', '/Library/Python/2.7/site-packages/matplotlib-override', '/Library/Frameworks/GDAL.framework/Versions/1.11/Python/2.7/site-packages', '/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python27.zip', '/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7', '/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-darwin', '/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac', '/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac/lib-scriptpackages', '/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk', '/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-old', '/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload', '/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages', '/Library/Python/2.7/site-packages', '/Users/Lucy/.qgis2/python/plugins/mmqgis/forms', '/Applications/QGIS.app/Contents/Resources/python/plugins/fTools/tools']

An error has occured while executing Python code:  Traceback (most recent call last):   File "/usr/share/qgis/python/pyplugin_installer/installer_data.py", line 460, in xmlDownloaded     if isCompatible(QGis.QGIS_VERSION, qgisMinimumVersion, qgisMaximumVersion):   File "/usr/share/qgis/python/pyplugin_installer/version_compare.py", line 188, in isCompatible     if len(maxVer)TypeError: object of type 'NoneType' has no len()  Python version: 2.7.6 (default, Mar 22 2014, 23:03:41)  [GCC 4.8.2]  When trying to open the plugin manages on Qgis 2.6.1 I get the following error:  QGIS version: 2.6.1-Brighton Brighton, exported  Python path: ['/usr/share/qgis/python/plugins/processing', '/usr/share/qgis/python', u'/home/joseph/.qgis2/python', u'/home/joseph/.qgis2/python/plugins', '/usr/share/qgis/python/plugins', '/usr/lib/python2.7', '/usr/lib/python2.7/plat-x86_64-linux-gnu', '/usr/lib/python2.7/lib-tk', '/usr/lib/python2.7/lib-old', '/usr/lib/python2.7/lib-dynload', '/usr/local/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages/PILcompat', '/usr/lib/python2.7/dist-packages/gtk-2.0', '/usr/lib/pymodules/python2.7', '/usr/lib/python2.7/dist-packages/ubuntu-sso-client', '/usr/share/qgis/python/plugins/fTools/tools']


The following type of question is quite popular with examiners at the institution where I study.  Find an equation of the plane containing the point $(0, 1, 1)$ and perpendicular to the line passing through the points $(2, 1, 0)$ and $(1, -1, 0)$  I start by calculating the the parametric equation of the line passing through $(2, 1, 0)$ and $(1, -1, 0)$, but after that I am lost.  I realize that I have to find the equation for the second line, and that the first plane will be perpendicular to it if the dot product of the vectors equal zero, but I cannot seem to put the pieces together.  Can someone please guide me in the correct direction for solving this type of problem?  Much appreciated.

Find an equation of the plane containing the point $(1, 1, -1)$ and perpendicular to the line through the points $(2, 0, 1)$ and $(-1, 1, 0)$  This is what I have:  I first find the vector between the points: $\vec{n}^{\ } = (2,0,1) - (-1, 1, 0) = (3, -1, 1)$  Next I find the formula for the plane that is perpendicular to the vector by taking the dot product of the vector and the given point + another point of the plane  $(3, -1, 1) \cdot (1 + x, 1 + y, z -1 )\\ 3 + 3x -1 - y -1 -z\\ 3x - y - z +1 = 0$  I am not at all sure if I followed the correct steps


Is there a word for a group of people that know they're doing something wrong, but they don't want to stop in fear of embarrassing themselves or letting their peers down? An example sentence would be   It's no use trying to reason with them – they're all just [...]s."

What is a word to describe the behaviour where you do something because everyone is also doing this, to the point where you do it without any clear reason?


If we say $V$ is $dim = 1$, can we say the only possible subspace is $sp\{0\}$?

Consider a vector space $V$ , show that: "$dimV=1\Leftrightarrow V$  has exactly two subspaces". Well I can understand that since $dimV=1$ the only subspaces are the zero and it self, but how can i prove that? How can I prove the equivalence? Thanks in advance.


The whole question is like this:  1-4. Let M be a topological manifold, and let U be an open cover of M .  (a) Assuming that each set in U intersects only finitely many others, show that U is locally finite.  (b) Give an example to show that the converse to (a) may be false.  (c) Now assume that the sets in U are pre compact in M; and prove the con- verse: if U is locally finite, then each set in U intersects only finitely many others.  I'm still tackling the part b).  From John Lee, "Smooth manifold" Problem 1-4

This problem is from John Lee's "Introduction to Smooth Manifolds"  1-4. Let M be a topological manifold, and let U be an open cover of M .  (a) Assuming that each set in U intersects only finitely many others, show that U is locally finite.  (b) Give an example to show that the converse to (a) may be false.  (c) Now assume that the sets in U are pre compact in M; and prove the con- verse: if U is locally finite, then each set in U intersects only finitely many others.  I think I have been able to successfully proof part a). I am stuck on part b) and c).  Any help is appreciated!


Paid for and downloaded Ubuntu 16.04 TLS. I have the "ubuntu-16.04.1-desktop-amd64.iso" on a 4gb USB drive.   Question How can I install the .iso file?  I think I need to convert the .iso file into a bootable USB ... however, I only have the "Ubuntu 16.04 TLS" from the original USB I bought, it wont load, something wrong with USB, it errors out ... but, the Ubuntu 16.04 TLS USB has an option to bootup Ubuntu to see if we like it ... (note: this is different from the install version).    Is there a tool I can access on the web, while in the Ubuntu test version, that will covert the .iso to a bootable USB?  Thank you, Don

I would like to see a full how-to guide on how to install Ubuntu.


I keep getting an error every time I try to call updateList() from my adapter class. When I change updateList() to public static void it seems like it would work, but then I can't use this as context and I don't know an alternative.   I'm new to android and would really appreciate the help.  MainActivity.class       public class MainActivity extends AppCompatActivity { public void updateList(){         listitems = new ArrayList<>();         adapter = new MyAdapter(listitems, this);         recyclerView.setAdapter(adapter);}}   MyAdapter.class  public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> { MainActivity main = new MainActivity();  holder.setOnItemClickListener(new ItemClickListener() {             @Override             public void onClick(View view, int position, boolean isLongClick) {  if{  AlertDialog.Builder altdial = new AlertDialog.Builder(context);                     altdial.setMessage("Gelukt?").setCancelable(true)                             .setPositiveButton("Yes", new DialogInterface.OnClickListener() {                                 @Override                                 public void onClick(DialogInterface dialogInterface, int i) {                                     if (listItem.getColor() == Color.BLACK) {                                           if (shared.loadDoneState() == 1) {                                             hoi[0]--;                                         } else if (shared.loadDoneState() == 2) {                                             hoi[1]--;                                         } else if (shared.loadDoneState() == 0) {                                             hoi[2]--;                                         }                                     }                                       shared.setDoneState(1);                                     shared.Recast();                                     dialogInterface.cancel();                                     Toast.makeText(context, "GOOD JOB :D", Toast.LENGTH_SHORT).show();                          /*-->*/    main.updateList();   2019-08-28 19:49:05.413 30203-30203/com.reaper.newlife E/AndroidRuntime: FATAL EXCEPTION: main     Process: com.reaper.newlife, PID: 30203     java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.RecyclerView.setAdapter(android.support.v7.widget.RecyclerView$Adapter)' on a null object reference         at com.reaper.newlife.View.MainActivity.updateList(MainActivity.java:142)         at com.reaper.newlife.Logic.MyAdapter$1$2.onClick(MyAdapter.java:189)         at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:172)

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


For $n\in \Bbb N$, find and prove a formula for $$\sum_{i=1}^n(2i-1)$$  How do I use induction to find a formula for it? I haven't not encountered any question like this in my textbook.

I'm not too sure exactly how to approach this question. Would anyone be able to give me any helpful advice or some sort of direction? I have a little problem with induction.   Prove by induction that:  $$1 + 3 + 5 + 7 +...+ (2n+1) = (n+1)^2 \quad\forall n \in \mathbb N $$


i am not sure whats the problem with mysql statement. The error says " IN is not valid at this position , expecting : EOF, ';'  Here is my sql statement:   CREATE VIEW collab AS  SELECT a.author_name AS Author, ca.no0fCollab  FROM (SELECT * FROM author) as a, (SELECT * FROM coauthors) as ca      WHERE a.author_id = ca.author_id  AND a.author_id IN (   SELECT UA.author_id   FROM uniq_authored UA JOING publication p    ON P.pubid = UA.pubid   WHERE (p.pubkey LIKE 'journals/%' OR p.pubkey LIKE 'conf/%')   AND p.title LIKE '%data%'   );

In MySQL 5.0 why does the following error occur when trying to create a view with a subquery in the FROM clause?     ERROR 1349 (HY000): View's SELECT contains a subquery in the FROM clause   If this is a limitation of the MySQL engine, then why haven't they implemented this feature yet?  Also, what are some good workarounds for this limitation?  Are there any workarounds that work for any subquery in the FROM clause or are there some queries that can not be expressed without using a subquery in the FROM clause?    An example query (was buried in a comment):  SELECT temp.UserName  FROM (SELECT u1.name as UserName, COUNT(m1.UserFromId) as SentCount        FROM Message m1, User u1        WHERE u1.uid = m1.UserFromId        Group BY u1.name HAVING SentCount > 3 ) as temp


For Convention badge, should all posts have score of 2 or more, or should have 10 posts and one of them could have score of 2?

Formerly List of all badges with full descriptions.  What are badge name's requirements? Why didn't I get badge name ? Which badges can I earn multiple times?    Jump to:                    Note: Some badges are awarded based on score. The term score means the total number of upvotes minus the total number of downvotes.  Any badge with a *** next to it is one of 20 badges that count towards the  displayed on a moderator candidate in an election. The candidate score is a total of 40 points: the first 20 are awarded based on the user's rep divided by 1000 and rounded down; the second 20 represents the total number of unique badges earned of the 20 that count. Note that if the same badge is earned multiple times, it will only count once towards the candidate score.  Any badge with a "(retired)" next to it is no longer awarded, but is retained by users who previously earned them. See  for more info on what it means for a badge to be retired.       Visit the  of the  on any site to see a complete list of badges that you can filter by earned, unearned, or type.


The question's simple enough I suppose. To launch a .exe file with wine from just double-clicking the .exe file.   On Ubuntu 17.10

I have Wine installed and several Windows applications installed there run fine, if I start them using the right mouse menu "Open with Wine program loader". But if I try starting an .exe file by just double clicking instead, the archive manager tries to open the executable.  How do I fix that?  And something like a bonus question as a former Windows user: Can this be done easily for a single file I currently see in the file manager (similar to the "Open with..." context menu in Windows) and for many file types together (like in Windows, using the menu "Folder settings" in the Explorer)?


I don't know if it's the right place to ask this, please correct me if that's the case.  The "snow" effect on the Winter Bash page is pretty cool, is that an open source plugin? I was looking at the code, but it's (obviously) minified/obfuscated. Is it something we can use ourselves?

This years 2013 Winter Bash canvas based  is quite lovely.        If you don't mind my asking, to whom should credits be given for that?    There must be a unicorn in there somewhere...


Let $R$ be a ring, and an ideal $I = ( p(x) )$ of $R[x]$. Then consider the statement: " $I$ is a maximal ideal if and only if $p(x)$ is irreducible " Does that statement need the hypothesis "$R[x]$ is a principal ideals domain" to be true? Or is that statement true anyway?

Let $R$ be a commutative, unital ring and let $I$ be an ideal of $R.$ Prove that if $I$ is maximal then $R/I$ is a field.   This problem is probably trivial for most of you abstract algebra fans out there, but remember that I'm new to the field, so please don't use some next-level math that I can't understand at all. I think this problem could be solved using next-level math very quickly though.   For this problem, I know that fields are commutative, unital, and every nonzero element is a unit/invertible. Also, $I$ is maximal wrt subset, so if there is an ideal that contains $I,$ then it must be $R.$


I want to have a terminal output on both terminal and output file. I am using argparse-python library while using this library I can't able to do both either I have to save output in a file or only in console. Can anyone help me with this?  I am using the following command to redirect and print the output.   some_command >&1 some_file.txt   It works when I am not using an argparse library. but with the argparse, I am getting the following error.  main.py: error: unrecognized arguments: main.txt

In bash, calling foo would display any output from that command on the stdout.  Calling foo > output would redirect any output from that command to the file specified (in this case 'output').  Is there a way to redirect output to a file and have it display on stdout?


Canon seems to plan to introduce a 50mm with apodization for a more natural bokeh [1], but it is not the first in photography [2]. Wikipedia article is only an introduction [2], and does not develop the physics behind.   What is the quantitative physics (mathematics) behind ? Which physical quantity can we build to quantify this esthetical quality manifested in the bokeh ? How do we achieve this in terms of engineering with a piece of glass ?   [1]   [2]

The new  has an "apodization" filter, which  "smoothes the outline of the subject to create a more natural bokeh effect".  The  mentions photography, and says that "usually it refers to a non-uniform illumination or transmission profile that approaches zero at the edges" and that a previous Minolta/Sony lens uses "a concave neutral-gray tinted lens element as apodization filter".  So, is this just an internal filter which gradually gets darker near the edges (presumably reducing "bright line" bokeh")? Or is it something more complicated?  How big of a deal is this in practical use (or is it mostly a gimmick)? Is this something that is always fundamentally better for natural, smooth bokeh, or can that be achieved in different ways through other types of designs which wouldn't benefit from also having this?  Could the same thing be achieved with a screw-on filter for any lens, or is it essential that this filter be internal?


Hello guys I just started learning java and I'm got my name in ascii numbers in a int array and i'm trying to loop thru it while casting each int ascii to a char  package program1;  /**  *  * @author Gust-X  */ public class Program1 {      /**      * @param args the command line arguments      */     public static void main(String[] args) {          int[] firstName;         firstName = new int[6];          firstName[0] = 071;         firstName[1] = 117;         firstName[2] = 115;         firstName[3] = 116;         firstName[4] = 097;         firstName[5] = 118;           for(int x = 0; x < 6; ++x ){             System.out.print((char)firstName[x]);         }         // TODO code application logic here     }  }   I get a red line under firstName[4] = 097; saying integer number too large 097

This prints 83  System.out.println(0123)   However this prints 123  System.out.println(123)   Why does it work that way?


In the ring, $\mathbb{Z}_p$, $p$ a prime, prove that $(a+b)^p=a^p+b^p$. The hint that is given to us says that the binomial expansion works in commutative rings, but I think I used something much more simple? I said that $\mathbb{Z}_p$ of prime order is cyclic, so $\langle x\rangle = \mathbb{Z}_p$ is generated by $x$. So therefore $x^p \bmod p = x$. Thus in $\mathbb{Z}_p,(a+b)^p = a+b = a^p +b^p$ The only thing I am unsure of is if I have to prove that $x^p \bmod p = x$, and then if I can apply it to $(a+b)^p$. If this way is super is super goofy and, even if it works somehow, requires a lot of proof, then how might I get started on the binomial theorem? Thanks team.

If $p$ is prime, then $(x+y)^p=x^p+y^p$ holds in any field of characteristic $p$. However all the proofs I have seen use induction and some relatively nasty algebra despite how fundamental this fact seems.  What is the nicest, "highest level proof" you know?


Not sure if this is the intended behavior of the badge system. Reproduction steps:  Flag a question (eg: duplicate) Get awarded Citizen Patrol Retract the flag  Expected result:  Badge rescinded  Actual result:  Badge is not rescinded

I recently flagged a question on webapps.stackexchange.com and after around an hour received the Citizen Patrol badge. Does this means action has been taken against the question I flagged? - i.e., did it get closed/migrated or whatever was applicable?


Lets say I have the html as below:  <h3 class="search-result-title">             This is a test             <small class="search-result-subtitle">                 Some more explanation             </small>         </h3>   How can I filter the text This is a test  without the small ?  Edit: I am using it with the symfony Dom Crawler.   So I have filter(a. h3 search-result-title); But I don't want the contents of the small element.

I would like to get all descendant text nodes of an element, as a jQuery collection. What is the best way to do that?


I have a query     SELECT employeedept, execoffice_status, employee, COUNT(*) AS 'employeetotal', YEAR_cse1 =YEAR(execoffice_date) FROM CSEReduxResponses WHERE execoffice_status = 1 GROUP BY employeedept, execoffice_status, YEAR(execoffice_date), employee  order by [YEAR_cse1], LIMIT 20   Which when I add the LIMIT it gives me a error "Incorrect syntax near '20'.".  Is there another way to get the top 20?  I have  Microsoft SQL Server Management Studio  10.0.2531.0, SQL server 2008.

I have found a way to select random rows from a table in . A suggestion is to use the following query:  SELECT * FROM employee ORDER BY RAND() LIMIT 1   But when I run this query in MS SQL 2005, I get the following error message  Msg 102, Level 15, State 1, Line 1 Incorrect syntax near 'LIMIT'.   Can anyone tell me where am I wrong? Doesn't MS SQL support LIMIT? If so, then how can I do this?


This is a question in ordinal arithmetic. (If anyone has read 'Classic Set Theory' by Derek Goldrei, this question comes from page 252.)  $\epsilon_0$ = sup {$\omega$, $\omega^\omega$, ... } and $\omega$ is the smallest infinite ordinal.   $\omega_1$ is the least uncountable ordinal so that $\alpha < \omega_1$ if and only if $\alpha$ is a countable ordinal.  I will take the definition of an ordinal to be: a set $\alpha$ is an ordinal if (i) $\alpha$ is well-ordered by $\in$ and (ii) if $\beta \in \alpha$ then $\beta$ is a subset of $\alpha$. (or $\alpha$ is $\in$-transitive).   I am also not assuming that $\epsilon_0$ is countable at this point.

In , it says that any epsilon number with the index that is countable is countable. How is it? Out of all those numbers, I especially want to know why $\epsilon_0$ is countable.  Thanks.


Suppose I have 9 screens put together like a square or a rectangle or any shape, and I want to display one image, but this image should be separate to 9 parts, each part will be shown on one screen like this :    What I want to do is bigger that 9 screens, this is for my project, I will create a video, inside the video there is a shape moves around. For example, if the shape were in screen 2, then it goes to screen 3 but slowly not disappearing in screen 2 and show up in 3.  It must be treat like a normal screen.  Is this possible?

I want to set up a system with (9) monitors arranged in a 3x3 grid.  Is this configuration possible with Windows 7? Does it max out at a set number of monitors?  Any suggestions about known working hardware combinations would be much appreciated.  Currently considering (3) nVidia Quadro NVS420 cards to drive the array.


Every quantity in Physics has a unit. These units can be in 3 forms:   A single unit. An example is kg or m or J A division of two or more units. An example is $\frac{m}{s}$ or $\frac{m}{s^2}$ A product of two or more units. An example is $N \cdot m$ or $J \cdot s$   The first case is simple. A person whose mass is 70 kg simply has a mass of 70 kg, simple enough.   The second case is also very simple. A speed of 1 $\frac{m}{s}$ means that 1m of distance is covered per second/every second.  The third case, however, has eluded me for a long time. What does it mean to have a unit like $N \cdot m$? What does the multiplication sign between the newton and meter mean? I tried stripping down the unit to the fundamental parts and I got $\frac{kg \cdot m^2}{s^2}$, which does not help.  Can someone please provide me with an understanding of a unit made of a product of two or more other units?

This question isn't just about kilogram-meters, it's about multiplied units in general.  I have a good mental conception of divided units, e.g. meters per second or grams per cubic meter.  Meters per second just (usually) means how many meters are traversed by an object each second.  Simple.  But I don't really have a mental conception of what it means when units are multiplied, e.g. a kilogram-meter.  Can anyone explain in simple physical terms what a kilogram-meter is?


When debugging in PHP, I frequently find it useful to simply stick a  in my code to show me what a variable is, what its value is, and the same for anything that it contains.  What is a good Python equivalent for this?

So what I'm looking for here is something like PHP's  function.  This is so I can debug my scripts by seeing what's the state of the object in question.


I made a question post on stack overflow.  The next day there were about 10 views and there was a - 3 score on my unanswered (of course) question.  Does this mean that three people thought it was a bad question and are allowed to be anonymous judges?  What is the purpose of this anonymous voting?  Can I just page about all I want and dis people's questions?

Why is there no possibility to make upvotes onymously? Seeing positive votes from credible other members would highly increase transparency and trust in answers.   Has anything like that been tried out so far?   What strong opinions are against such an option? Why not even make such behavior default?