Ubuntu 16.04 - Unity doesn't load - no Launcher or Dash appears

UPDATE: None of the provided answer to this date (2017.10.16) have helped me solve the problem, so in a fair world no one should get the bounty. I should emphasis that the provided answer were either not in the direction of answering the question (like those who suggested installing Gnome) or their suggestion didn't work on the computer that I have this issue on. Nevertheless i appreciate the time and effort they have put into this.   This might look like a duplicate post but IT'S NOT since none of the suggestions and solutions in other posts worked in my case.  Problem description: Everything was going fine but I faces some sort of lags, so I rebooted the computer and after logging in to my account, Unity didn't load properly. I rebooted multiple times and ... Nothing.  What I did: I tried all the solutions and suggestion out there an none of the solutions out there worked. Things like:  the top 10 suggestions here:   or  unity-tweak-tool --reset-unity   or  unity --reset-icons   or  unity --reset   or  gconftool --shutdown sudo killall -r -I gconf sudo killall -r -I dconf rm -rf .compiz* .gconf* .config/dconf/ .config/compiz*   My Idea and question: Based on a suggestion of my friend, I tried to login with another user and it worked! everything was fine, which narrowed down that some settings in my account is corrupted!  The question is, Which files should I transfer from the other account that Unity works fine on to my own account?  When I try to run Unity from terminal I get the following:  $unity unity-panel-service stop/waiting unity7 stop/waiting unity-panel-service start/running, process 6549 unity7 start/running, process 6648


Need help removing Ubuntu from a single boot hard disk

I bought a used PC recently (an old hp 8200 elite) that arrived with ubuntu 19.10 installed.  I never used It and I want to install windows istead. The problem is I can't do anything on this os. Everything I try doesn't work.  The PC boots directly to ubuntu. There's no a second partition. I can't use windows tools since I can't open .exe files.    I tried Woeusb but after 1 hour of "installing for i386-pc" I gave up.  I tried to format manually, the usb drive I downloaded other programs since there was no a format option, nor I knew the command if there is one. After 40 minutes it gave me an error.   I feel like I never used a PC in my life. It's so frustrating.  Can you guys please help me?


How to decide where a machine learning question belongs: the AI Stack Exchange site, Cross Validated, Data Science SE, etc

If I have a machine learning question, I am able to post it in any of Cross Validated, Data Science SE, or AI SE. Does it make sense to have so many different places to post the same type of content rather than some consolidated place to post machine learning questions? Why should I pick one over another? All I'm able to infer from  that CV is aimed for more theoretical problems and Data Science is for more applied questions.    Where does that leave the AI SE?  What incentive is there to ever post in the AI SE over one of the other two, given that the other two have larger communities and are more likely to get a response back?  Also, since SE discourages cross-posting, how can I get my question to have the attention of both communities?


A stick is broken in three parts of any length ,  if we join the pieces then what's the probability of getting a acute angled triangle?


Can work done by friction be positive? Please explain with an example. Is the work done by friction on a moving car positive?


One Ubuntu 16.04 system finds the package libsqlite3-dev, but another does not

I do the following on one Ubuntu machine (Ubuntu 16.04.3 LTS)  sudo apt-get install libsqlite3-dev   it shows  E: Unable to locate package libsqlite3-dev   But if I perform the same command on the other one (Ubuntu 16.04.3 LTS too), it shows the following and the package is installed successfully   After this operation, 1,699 kB of additional disk space will be used. Get:1 http://sg.archive.ubuntu.com/ubuntu xenial/main amd64 libsqlite3-dev amd64 3.11.0-1ubuntu1 [508 kB]      Fetched 508 kB in 1s (383 kB/s)            Selecting previously unselected package libsqlite3-dev:amd64.   I suspect the repository:   http://sg.archive.ubuntu.com/ubuntu xenial/main amd64    is not in the first machine repository list. How should I add it?


I have two paths:   fred\frog   and  ..\frag   I can join them together in PowerShell like this:  join-path 'fred\frog' '..\frag'   That gives me this:  fred\frog\..\frag   But I don't want that. I want a normalized path without the double dots, like this:  fred\frag   How can I get that?


I have seen lots of examples of how to create a table in R from a data.frame, but my question is how can I create a table from a graph output in R?   I am working with the package AdehabitatHR, and I have produced some graphs showing variation in area (metres) as a function of $k$.  Thus can someone tell me how to create a table from a (xy) line graph.  This is my script  #Read the data file Ade <- read.csv("Ade.csv", header=TRUE, dec=",")  data <-SpatialPointsDataFrame(Ade[,4:5],as.data.frame(Ade[,2]))  #Check the data frame is correct str(data) head(data, 2) # Examines the changes in home-range size for various values of k LoCoH.k.area(data, krange=50:90, percent=95, unin = c("m"), unout = c("km2"),    duplicates=c("random"), amount = NULL)


I know the whole 200 400 800 is based on the speed of the film & say youre in a dark room with dim lighting, 800 would be a better choice to use.. But i have searched through flickr and i see most people using superia 200 film with their 35mm cameras . Why? The lower the number , the better the photo? It has been confusing me for a while now . I shoot with an olympus XA2 usually with a 400 roll & the right asa settings and a lot of my photos come out blurry or zoomed in for some reason. Im mostly concerned about technique and image quality . When i say quality i dont mean extremely sharp & clear either. I just dont want blurry photos & i dont mind the dreamy, light leaks either.     Sometimes the photos come out extremely highlighted & dark , unfocused , blurry .. I have half a roll that came out cluelessly out of focus & cropped even though i set the settings correctly .


Download and installation of LaTex for Linux Ubuntu

I'm using Ubuntu and I want to download and install LaTeX, what should I choose and where can I find it?   Thanks.


What does "paths must precede expression" mean when using find?

I want show all the files that have a .bak extension.  kaykav@ubu2:~/Documents$ ls cdIndex1-60  met.bak  tem.bak   I type the cmd :  $ find . -name *.bak  I'm in the correct Directory for this. I get the following message:     find: paths must precede expression: tem.bak   What does that mean? Man pages are no help.


Is being an honors student really worth it?

This is a something I'm really concerned about. I am an undergraduate physics major, and I've been in the honors program at my university for a little while now, and that means certain things. I must take at least 1-2 honors courses (or do an honors-contract in a normal course) every semester, I must make a yearly update to a personal portfolio/e-portfolio, I must obtain a sufficient amount of research-group credit hours before I graduate, and I must defend an undergraduate thesis.  I do like all of this, but what starts to bother me is one other requirement, as well as a few things within the program. We must attend at least one 'Honors Student Council' event per semester (not a big deal, but these are ridiculous/stupid most of the time). Also, most of the other students in the program are snobs and stuck-up compared to other non-honors students. I do like the chance to learn a lot more about the material presented in my classes through honors and course-contracted classes, but I'm starting to think that I could just do that on my own - that is, set that up with professors on my own.  However, I don't really know how useful having an 'honors' distinction on a degree will be. Is it very useful? I've been thinking of quiting the honors program, but I wouldn't want to do it if it will drastically hurt me later on. For example, how much of an impact does having an honors distinction have on graduate school/job applications?


I tried using this:  $ if [$a == 1] then { echo 'yes'; } fi;   but I get an error:  -bash: syntax error near unexpected token `}'   What is the correct format?  I tried several with no luck.


Android 10 system taking up too much hard drive space

I have a Nokia 5.3 running Android 10. Of the 64GB hard drive space, the system file is currently taking up 52GB. Couple of days back, it was taking up 48GB and my phone was complaining of running out of hard drive space, so I removed some old apps and files to free up some room, and now it looks like the system file has just expanded to take up the available free space, and again it's complaining about running out of hard drive space. How do I go about reclaiming some of the space taken by the system folder(s), as I can't believe that it's needed to write 4GB worth of data in a few days, nor that the OS really needs 52GB of hard drive space, when my old phone only had a 32GB hard drive for the same OS. (apologies, I'm not entirely sure what tags to use for this)


I am quite new in QGIS and I really need your help.  I have a map of Kenya divided into 68 districts and I have coordinates of 30.000 schools. The points have one variable besides the latitude and longitude data called "distance to nearest school".   First I imported the map. Then I imported the spreedsheet and transformed it to a SHP file like the map. So now I have two SHP files.    The points have three variables: "Latitude", "Longitude" and "Distance to nearest school". I want to have a fourth variable called "District" and take the mean of the "Distance to nearest school" for each district.


I want to download Ubuntu mobile os for android

I have dual core, 512 MB ram mobile device. Which Ubuntu OS can I install in my device? Please give me download links to support my mobile configuration.


Deleted /etc/apt, now apt-get gives a relocation error?

I was trying to delete the sources.list file for apt. After deleting, instead of issuing cd /etc/apt, I did sudo rm - r /etc/apt and now I've deleted it. I tried creating the /etc/apt directory again and running:   $ sudo apt-get update && apt-get upgrade    This returns an error message as follows:  apt-get: relocation error: /usr/lib/x86_64-linux-gnu/libapt-private.so.0.0: symbol _ZTI17pkgAcquireStatus2, version APTPKG_5.0 not defined in file libapt-pkg.so.5.0 with link time reference   How do I restore my /etc/apt directory and fix apt?


In page 29 of the third edition of the Python Cookbook, the author makes the following statement:     "... might also be done by creating a sequence of tuples and passing them to the dict() function. For example:           p1 = dict((key, value) for key, value in prices.items() if value > 200)      The author's referral of the argument passed to the dict() constructor as a "sequence" kinda got me wondering... what exactly is for ... in ...? It isn't an expression is it? One can't just type into a Python interpreter: for x in (1,2,3) and receive a result? The  for list(), for example suggests constructor expects an iterable but it's unclear to me what's going on.


I have a problem with encoding Polish letters in TeXmaker. What I mean by this is that:    when I write Polish letters in TeXmaker they are visible as Polish letters: ą, ę, ć and so on  yet after compilation what I get in dvi or pdf are just question marks similarly, if I open tex file written in TeXmaker and containing Polish letters in WinEdt, what I get are question marks as well if I produce a file containing polish letters in TeXmaker, close it and re-open in TeXmaker — again question marks   I know there must be some problem with encoding, yet I have no idea how to solve it.     The question has been marked as duplicate, however the original answer which was pointed to me does not concern the problem of Polish signs in TeXmaker and in a source file. Texenthusiast's answer below helped me to solve that problem as well.


Definition of quadratic residues in $\mathbb{F}_q$, where $q = p^n$.

For $\mathbb{F}_p$, I know that the definiton of quadratic residue (and non-residue)  is :  $a $ is a quadratic residue if $gcd(a,p) =1$ (i.e $a \neq 0 $ in $\mathbb{F}_p$) and $x^2 \equiv a $ $mod(p)$ has a solution.   $a $ is a quadratic non-residue if  $gcd(a,p) =1$ (i.e $a \neq 0 $ in $\mathbb{F}_p$) and $x^2 \equiv a $ $mod(p)$ has no solution.   Now what are the definition in case of $\mathbb{F}_q$ where $q=p^n$? Is the condition $gcd(a,q) =1$  there in the definition?   Also in case of $\mathbb{F}_p$ we get $(p-1)/2 $ residues and $(p-1)/2 $ non-residues. Is there a similar result in case of $\mathbb{F}_q$?


I am currently running a dual boot system for windows 10 and ubuntu 18.10. I have 1.5 TB for windows and 500 GB for ubuntu. I want to do a fresh installation of ubuntu 19.04, and completely remove windows from my laptop, giving me 2TB for ubuntu. I know how do a fresh installation, but I don't know how should I do it so as to remove windows and merge those 2 partitions into 1. Can someone please give me some hints on how I can do this? Thanks...  On a side note, I read on Ubuntu's site that that 19.04 won't receives updates after Jan 2020, does it mean that it may be a bad idea to install 19.04?


Customize nemo keyboard shortcuts in Ubuntu 13.04

I'm on Ubuntu 13.04 and ran through the steps outlined on .  I understand that Nemo is a cloned-fork off of Nautilus and was hoping that I'd be able to adjust the keyboard shortcuts for it in the same way... For Nautilus  we can edit the "accels" file at ~/.config/nautilus/accels.  Does Nemo not have this ability?  The version of Nemo on my system is 1.8.2.


Our names are personal things that people attach great value to, so in general we should try to accommodate a person's full name.  However at the same time, a persons name (especially in an app) is read by other people more often than it is read by themselves, and is primarily there to identify them to someone else.  So there is a solid argument for a name length limit.  The question then becomes, what a sane length limit is.  The  uses a limit of 70 characters for a full name field in their internal systems, but it seems to me that 70 characters is somewhat excessive if usability is the prime criterion.  Does anyone know of any studies on limiting a users name length (the name that is displayed, not their username) and the UX implications?  Feedback from experience and UX testing of this would also be good.    Please note that I am not asking how to display a long name or about technical issues in implementing long names.  For that there are already good answers. This is solely about the UX considerations in choosing a name length limit.


For a closed subset $Y$ of a space $X$ we have the following inequlity of topological (covering) dimensions: $$\dim{Y} \leq \dim{X}$$ (assuming at least one of those is finite).  I have two questions related to that:   Does the above inequality hold for any (not necessarily closed) $Y \subseteq X = \mathbb{R}^n$? Can you come up with some nice counterexamples to the above inequality when we skip the assumption that $Y$ is closed? By nice I mean something nicer than my counterexample described below.   Not nice counterexample  I'm not happy with it, because it is not even a Hausdorff space and it is quite artificial for me.  Let $C_n=[n-1,n] \times [0,1]^{n-1}$ ($C_1=[0,1]$). Then $D_m = \bigcup_{n=1}^m C_n$ (for $m \in \mathbb{N} \cup {\infty} $). Define the topology $\tau_m$ on $D_m$ with a normal euqlidean metric on $D_m \subseteq \mathbb{R}^m$. For $m<\infty$ $D_m$'s dimension is $m$ since it is a finite sum of closed subsets $C_n$ and maximum of their dimensions is $m$*. For $m=\infty$ we can notice that $D_N \subseteq D_m$, $D_N$ is closed and its dimension is $N$ and then go with $N$ to infinity.  The exact counterexample:  (1) We can define $(D'_m, \tau'_m)$ as $(D_m \cup \{Inf\}, \tau_m \cup \{D'_m\})$. Then its dimension is zero since the only open set containing $Inf$ is the whole space so it must be included in any open covering. However zero-dimensional $D'_m$ contains $D_{m'}$ for any $m' \leq m$, which dimension is $m' \gt 0$.  (2) Moreover one can define more additional (containing $Inf$) sets in topology in such a way that they don't have to contain the whole $D_m$ but only its "tail" without some initial part $D_{m'} \subsetneq D_m \subseteq D'_m$ ($m' \lt m$) and then the dimension of the whole space would be $m'$.  *I haven't seen the proof that $\dim{\mathbb{R}^n}=n$, but I strongly believe in it.  EDIT:  As Brian points below, my inequality is not true with Engelking's definition of $\dim$ with functionally open sets. The definition that I meant is the following (X is any topological space):     A space X is said to be finite dimensional if there is some integer $m$ such that for every open covering $A$ of X, there is an open covering $B$ of X that refines $A$ and has order at most $m+1$. The topological dimension of X is defined to be the smallest value of $m$ for which this statement holds; we denote it by $\dim$X.   (Munkres J.R., Topology, paragraph 50)  I'm sorry for the lack of precision.


Please explain to me this:  What is the physical mechanism of the field and atraction force; in which way a force (electro, magnetic or gravity) is transmited between two objects? I will try to explain that question with a few sub-questions (basicly the same ones): On the extreme basic level, the question is: how two particles (proton and electron) atract each other? I know they have opposite charges, but how that charges atract each other? How they "comunicate" that information? How they "produce" atraction force? On the other hand - is it the same mechanism with gravity force? How two bodies "comunicate" their masses? How they start to move toward each other despite their inertial masses? Where that energy come from? What is that force? I know it's a "bit" messy question, but what is the essence of that atraction?  Thanks a lot. Boris


What is the maximum AC possible without using magic items?

What is the maximum AC a PC can acquire without the use of magic items?  Allowed content are feats, spells, and temporary effects - but not effects from allies, magical items, or UA content.


Ward model implementation: specular component too weak

I'm trying to implement the Ward shading model, the anisotropic, computationally efficient version:       This is how I made it:    float alphaX=0.5, alphaY=0.5; // asinotropic roughness float minFloat= 1.e-6;   vec4 Ward(vec3 L, vec3 N, vec3 V) {     vec3 H= normalize(L+V);     float NdotL= max(dot(N,L),0.0);     float NdotV= max(dot(N,V),0.0);      vec3 e= vec3(1.0,0.0,0.0);     vec3 T= normalize(cross(N,e));     vec3 B= normalize(cross(N,T));     float HdotT= max(dot(H,T),0.0);     float HdotB= max(dot(H,B),0.0);     float HdotN= max(dot(H,N),0.0);      float beta= -2.0 * ( pow(HdotN/alphaX, 2.0) + pow(HdotB/alphaY,2.0) ) / (1.0 + HdotN);     float den= max(minFloat, 4.0 * pi * alphaX * alphaY * sqrt(NdotL * NdotV) );     vec4 specular= Ps * 1.0/den * exp(beta);     return (Pd + specular) * NdotL; }   But I get a result similar to a lambertian surface or Oren-Nayar model, where the specular component is absent:


An example of a group such that $G \cong G \times G$

I was trying to find an example such that $G \cong G \times G$, but I am not getting anywhere. Obviously no finite group satisfies it. What is such group?


Should exploratory data analysis include validation set?

I know that EDA should be performed on the training set but not on the test set.   But my question is: we usually split the training set into training and validation datasets. Should we perform EDA on both of them?


Questions about proving $\lnot \lnot a = a$

This is all in the context of a Hilbert system with modus ponens $A, A\to B \vdash B$ and axioms:  Axiom $1$: $A \to (B \to A)$   Axiom $2$: $(A \to (B \to C)) \to ((A \to B) \to (A \to C))$   Axiom $3$: $(\lnot B \to \lnot A) \to (A \to B)$  So I tried to prove double-negation elimination by doing the following:  \begin{array}{ccc} 1 & \{ \lnot \lnot a \} \vdash \lnot \lnot a & \text{Premise}\\ 2 & \{ \lnot \lnot a \} \vdash \lnot \lnot a \to (\lnot \lnot \lnot \lnot a \to \lnot \lnot a)  & \text{ Axiom } 1\\ 3 & \{ \lnot \lnot a \} \vdash \lnot \lnot \lnot \lnot a \to \lnot \lnot a  & \text{ Modus Ponens } 1, 2\\ 4 & \{ \lnot \lnot a \} \vdash (\lnot \lnot \lnot \lnot a \to \lnot \lnot a) \to (\lnot a \to \lnot \lnot \lnot a)  & \text{ Axiom } 3\\ 5 & \{ \lnot \lnot a \} \vdash \lnot a \to \lnot \lnot \lnot a  & \text{ Modus Ponens } 3, 4\\ 6 & \{ \lnot \lnot a \} \vdash (\lnot a \to \lnot \lnot \lnot a) \to (\lnot \lnot a \to  a)  & \text{ Axiom } 3\\ 7 & \{ \lnot \lnot a \} \vdash \lnot \lnot a \to  a  & \text{ Modus Ponens } 5, 6\\ 8 & \{ \lnot \lnot a \} \vdash a  & \text{ Modus Ponens } 1, 7\\ 9 & \vdash \lnot \lnot a \to a  & \text{ Deduction Theorem } \\ \end{array}  And then I continued on, to prove double negation introduction:  \begin{array}{ccc} 10 & \vdash \lnot \lnot \lnot a \to \lnot a & \text{Double Negation Elimination}\\ 11 & \vdash (\lnot\lnot \lnot a \to \lnot a) \to (a \to \lnot \lnot a) & \text{ Axiom } 3\\ 12 & \vdash a \to \lnot \lnot a & \text{ Modus Ponens } 10, 11\\ \end{array}  My questions:   Am I allowed to invoke the deduction theorem in the middle of a proof like this (step $9$)? Is this considered a context change? Is context-changing allowed? Are the proofs even right/correct? Assuming it's all correct: Are we able to combine them to say that $a \to \lnot \lnot a$ and $\lnot \lnot a \to a$, therefore $a \iff \lnot \lnot a$ or is this symbol not allowed? What ultimately let us say $\lnot \lnot a = a$, the use of the equal sign here?


Ubuntu OS install in Android Mobile device using ubuntu-device-flash

For past few days I have been looking for a way to install Ubuntu Touch on my Moto-G(XT1033). So I tried some process and it failed with failed to enter recovery.  root@ram:/home/ram/Downloads# ubuntu-device-flash touch --channel=ubuntu-touch/stable/ubuntu --bootstrap --device=mako     2015/11/02 23:24:46 Device is |mako|     2015/11/02 23:24:46 Flashing version 24 from ubuntu-touch/stable/ubuntu channel and server https://system-image.ubuntu.com to device mako      Failed to enter Recovery      +++++   Could anyone please help me on this issue. And if there is any process that was working for the installation of Ubuntu OS in mobile, please comment out here. Thanks in advance.


I'm trying to filter every string which are not valid (simple) email adress. Thus starting with a dot is a "no go".  But my expression doesn't reject strings like .test@test.be  preg_match('/^(?<!\.)[\w0-9\.]+(?<!\.)@+(?<!\.)[\w0-9\.]+\.\w{1,3}(\s*<[^>]+>)?$/', $part)  Shouldn't /^(?<!\.) do the trick?  EDIT: This question is not a duplicate of the indicated question.  I am not asking about the context, I want more information about look behind, the approach itself, not the specific use-case.


Probability of algebraic solutions for polynomials with integer coefficients

Polynomials of degree larger than 4 with integer coefficients may have non-algebraic solutions, that is, zeros that do not have an  (over the integers).  How likely is this to happen?  For example, of the $(2M+1)^{n}$ polynomials of degree less than or equal to $n\geq 5$ with coefficients in $\{-M,\dots,M\}$, what is the asymptotic behavior, as $M\to\infty$, of the proportion of those polynomials with no/at least one/only algebraic solutions?


When I try the command  drush sql:sync @dev.dev @self or drush sql:sync @dev.dev @local it errors with:   Undefined class constant &#039;MYSQL_ATTR_SSL_CA&#039; in Drush\Sql\SqlMysql->creds() (line 60 of /Users/kevinquillen/Servers/foo/vendor/drush/drush/src/Sql/SqlMysql.php).  [error]  Drush command terminated abnormally due to an unrecoverable error. [5.47 sec, 7.92 MB]   [error]  Failed to import /tmp/foo_20180405_152230.sql.gz into target. [5.48 sec, 7.91 MB]   Previously, I could do drush sql-sync @source @destination and it worked just fine (from the host OS).  Not really sure where to go from here, I recently upgraded from Drush 8 to 9. The problem also happens on another project.  drush @local sql:connect -vvv works. A basic query with sql:query also works.  Why can't I sync from remote to local anymore after the upgrade?  Remote environment: Acquia Cloud  Local environment: DrupalVM  DrupalVM config.yml:  # Update the hostname to the local development environment hostname. vagrant_hostname: local.mysite.com vagrant_machine_name: mysite  # Set the IP address so it doesn't conflict with other Drupal VM instances. vagrant_ip: 0.0.0.0  # Use Ubuntu 16.04 LTS to match Acquia Cloud environments. vagrant_box: geerlingguy/ubuntu1604  # Set drupal_site_name to the project's human-readable name. drupal_site_name: "My Site"  # Provide the path to the project root to Vagrant. vagrant_synced_folders:   # Set the local_path for the first synced folder to `.`.   - local_path: .     # Set the destination to the Acquia Cloud subscription machine name.     destination: /var/www/mysite     type: nfs  drupal_build_composer_project: false # Toggling this to `true` would invoke `composer install` with the # projects own `composer.json` successfully. drupal_build_composer: false drupal_composer_path: false drupal_composer_install_dir: "/var/www/mysite" drupal_core_path: "/var/www/mysite/docroot" ssh_home: /var/www/mysite  drupal_db_user: drupal drupal_db_password: drupal drupal_db_name: drupal  # Set this to 'false' if you don't need to install drupal (using the drupal_* # settings below), but instead copy down a database (e.g. using drush sql-sync). drupal_install_site: false  # Drupal VM automatically creates a drush alias file in your ~/.drush folder if # this variable is 'true'. configure_drush_aliases: false  # This is required for front-end building tools. nodejs_version: "9.x" nodejs_npm_global_packages:   - name: bower   - name: gulp-cli   - name: yarn nodejs_install_npm_user: "{{ drupalvm_user }}" npm_config_prefix: "/home/{{ drupalvm_user }}/.npm-global" installed_extras:   #- adminer   - drupalconsole   - drush   - mailhog   - memcached   - nodejs   #- solr   #- selenium   - xdebug  # PHP 5.6 (PHP 7.1 is being tested, see: https://docs.acquia.com/node/25726). php_version: "7.1" php_install_recommends: no php_memory_limit: "256M" php_display_errors: "On" php_display_startup_errors: "On" php_realpath_cache_size: "1024K" php_sendmail_path: "/opt/mailhog/mhsendmail" php_opcache_enabled_in_ini: true php_opcache_memory_consumption: "192" php_opcache_max_accelerated_files: 4096 php_max_input_vars: "4000"  php_packages_extra:   - "php{{ php_version }}-bz2"   - "php{{ php_version }}-imagick"   - imagemagick  # XDebug configuration. # Change this value to 1 in order to enable xdebug by default. php_xdebug_default_enable: 1 php_xdebug_coverage_enable: 0 # Change this value to 1 in order to enable xdebug on the cli. php_xdebug_cli_enable: 0 php_xdebug_remote_enable: 1 php_xdebug_remote_connect_back: 1 # Use PHPSTORM for PHPStorm, sublime.xdebug for Sublime Text. php_xdebug_idekey: PHPSTORM php_xdebug_max_nesting_level: 256 php_xdebug_remote_port: "9000"  post_provision_scripts:   - "../../../acquia/blt/scripts/drupal-vm/post-provision.php"


How to solve the E:Malformed entry 55 in list file /etc/apt/sources.list (Component), problem

I am new to Ubuntu and so far I have this problem: I've tried to install skype and couldn't do it. Then the software "app" stop working and I get an error of Failed to load the package list, followed by details:  E:Malformed entry 55 in list file /etc/apt/sources.list (Component),   E:The list of sources could not be read.   I'm really rookie at this, but I've tried my best figuring out through older ask ubuntu questions of the "E:Malformed entry 54"  but that is not working.   Please help.


I've looked at a lot of similar questions about this but haven't found anything to solve my issue.  I would like to be able to open an ssh connection to my university's server and keep the connection open in the background. What I'm doing is I ssh into the uni server and run a script, then scp a file from there to my remote, like:  $ssh remote@remote.edu "./bin/script" remote@remote.edu's password: $scp remote@remote.edu:~/some_file.txt . remote@remote.edu's password:   I do this sequence of commands a ton, and eventually my connection gets refused because the university mistakes it for malicious software. So what I'd like to be able to do is open the ssh connection once, then keep it open so I can continuously run the script on the remote server. I don't want to open the ssh connection in another terminal as its very annoying having two terminals open and constantly alt+tab'ing to the wrong one. Surely there must be a way to do this, I would really appreciate some help.


Continuity definition by image rather than pre-image

One definition of continuity is that the pre-image of an open set is open. Can I define Continuity as that the image of an open set is open AND the image of close set is close? If this is not correct, are there any counterexamples?


Why $ \sum_{k=0}^{\infty} q^k $ sum is $ \frac{1}{1-q}$ when $|q| < 1$

Why is the infinite sum of $ \sum_{k=0}^{\infty} q^k = \frac{1}{1-q}$ when $|q| < 1$  I don't understand how the $\frac{1}{1-q}$ got calculated. I am not a math expert so I am looking for an easy to understand explanation.


How to show this  $$\sum_{k=0}^{n-1} [x+\frac{k}{n}]= [nx]$$ for every $x\in \mathbb{R}, n\in\mathbb{N}$. Where the function $[x] = \max\{p \in\mathbb{N}: p\leq x\}$ is the floor function?


Give examples of compact spaces $A,B$ such that $A\cap B$ is not compact

If a topological space is Hausdorff then arbitrary intersection of compact sets is compact.  How to find examples of compact  subsets $A,B$ of a topological space $X$ such that $A\cap B$ is not compact


What does particles with asterisk superscript * mean, such as $Z^*$ or $W^*$, in decay production?

I can always find that in some articles the production of higgs decay written as "$\rm H\to {ZZ}^*\to 4l$", "$\rm H\to ZZ\to 4l$", "$\rm H\to Z\gamma^*\to\ldots$” What dose it mean when some particles with a superscript *? Such as “$\rm Z^*, W^*, \gamma^*, \ldots$". What’s the difference between them and "$\rm Z, W, \gamma$"?


I know the CMYK code.(100, 64, 0, 75) I want to know the Ral color for this code. I need help from someone I know.


Consider $n$$(>1)$ spots created around a circle. A man jumps from one spot to another in the following manner. He starts from some selected spot. From there, he skips exactly one spot in the clockwise direction and jumps to the next one. Then skips two spots and jumps to the next and then three spots and so on. He is allowed to visit the same spot more than once. Suppose that after some time he ends up visiting all the spots. Is it possible for the value of $n$ to be odd?   Well, the answer is obviously no. I tried to assume that it is odd and then take "$\mod n$" to prove that all possible remainders will not come. Though that seems to be the right path, I am not able to conclude. Please help!


python: can I reimport an external config file and let the program read it without restarting the program itself?

Sorry, I'm new to python, and I'm struggling finding what I need. I'm also sorry on how I wrote the title (probably the same reason why I can't find what I need, I don't know what to search for..) The question is really simple, but I don't know if it can be done. I have a python file (bot.py) which reads some variables from another file (a configeth.py file). import configeth  so, is there any way for me to edit the "configeth.py" file while the bot.py is still running, and tell him to import and use the updated file without having to kill the bot and start it again??? thanks a lot, really appreciated.


This code is working as expected.  [user@linux ~]$ cat script.sh #!/usr/bin/bash file="$1" while read IP; do     echo xx $IP done < "$file" [user@linux ~]$   ip.txt  [user@linux ~]$ cat ip.txt 127.0.0.1 127.0.0.2 127.0.0.3 [user@linux ~]$   output  [user@linux ~]$ ./script.sh ip.txt xx 127.0.0.1 xx 127.0.0.2 xx 127.0.0.3   But when I put xx to the end, it's replacing 127.  #!/usr/bin/bash  file="$1" while read IP; do     echo $IP xx done < "$file"   What's wrong with this code?  [user@linux ~]$ ./script.sh ip.txt  xx.0.0.1  xx.0.0.2  xx.0.0.3 [user@linux ~]$   dos2unix? Tried that many times, didn't work  [user@linux ~]$ dos2unix script.sh dos2unix: converting file script.sh to Unix format ... [user@linux ~]$ [user@linux ~]$ ./script.sh ip.txt xx 127.0.0.1 xx 127.0.0.2 xx 127.0.0.3 [user@linux ~]$   p/s - not sure the best subject for this question. If you have better suggestion, let me know


Word Question Involving the Definition of the Derivative

A skydiver jumps out of a plane from a height of $2200$m. The skydiver's height, $h$ meters above the ground, can be modeled by the function $$s = 2200 - 4.9t^2$$ How fast is the skydiver falling at $t = 4$s?  If the skydiver is approaching a height of $2200$m, I reasoned that I could use the following definition to find the solution $${f(x+h)-f(x)\over h}$$ I entered the function into this definition and got stuck when I got to this$$f'(x) = \lim_{x\to 0} {2200-4.9t^2-9.8th-4.9h^2\over h}$$ Where can I go from here? Can I continue with this method or did I make a mistake a few steps back? New Solution  How does this look?


Let K={(1),(12)(34),(13)(24),(14)(23)} show that K is a normal subgroup of the alternating group of degree A4 and find all the members of A4/K and write down the group table for A4/K.   i know that K is the Klein four group and i have already proven it is a normal subgroup but i need a start on approaching the A4/K part of this question no direct answers are necessary,just ideas thank you! :)


Recently, I was reading about Hawking Radiation in A Brief History of Time. It says that at no point can all the fields be zero and so there's nothing like empty space(quantum fluctuation etc.). Now, the reason mentioned was that virtual(force-carrier) particles cannot have both a precise rate of change and a precise position(Uncertainty Principle).  So, my question is :  video says that virtual particles don't follow normal physical laws. So, how can we say that they obey the uncertainty principle?


Is this grammatically correct - "I miss to swim"

I read  article and here it is mentioned that "I miss to swim" is grammatically incorrect. However, I do not see any issue with it.  Could some language expert please clarify.


What are pros and cons for MacPorts, Fink and Homebrew?

I'm just migrating from Ubuntu Linux to Mac, and everything is new and I'm re-learning a lot of stuff.  On Linux I had the excellent apt-get to manage software packages. I googled for an alternative on Mac and found about MacPorts, Fink and Homebrew.  I will use this computer primarily to develop Ruby on Rails applications.  So, what are the differences between them? Which are the upsides and downsides? Which one is best maintained and has more packages?


I tried to quit from the musical community, I logged off, I tried to follow the instructions that I found in other responses here in Meta, but no matter what I do, I still have a user account there. How can I quit from a community?  Thanks!


Is this true?  If $A$ and $B$ are sets, then $A=\emptyset $ if and only if $B = A \bigtriangleup B$.  If $A=\emptyset$ then $B=\emptyset$ too?  Could someone help me please?


Story identification: Short story from late 70s re simultaneous past/present/future

Trying to identify a short story (possibly read in Asimov's SF magazine) from the late 70s. A man - possibly a professor or scientist - is working or somehow involved with a young man and young woman. I think they have some interest in either time travel or the properties of time. The professor/scientist has a device or capability that allows him to see the couple's past/present/future - basically their entire lives) at the same time.


Number of Subspaces that contains other Space

In $GF(2)$, How Can I calculate the number of subspaces of dimension $k<w$ that contains a fixed subspace of dimension $k'<w$:


Looking for the language to describe a solution I am looking for...  As a systems admin for an educational institution, I would like to: a) post our tests in an encrypted form b) at a certain time, make the contents available to the user (online or not) c) after a certain time, re-encrypt the file, and/or delete the content.  During the unencrypted time, I would like to prevent copy operations, cut/paste etc. to protect the content...  Is this "mission impossible" type encryption style even possible to protect our content?  If so, what would it be called?  Many thanks for your assistance


Getting NullPointerException in Java for loop

I have 3 classes, Main, Contacts, and ContactsManager. I'm getting the following error in my "searchContact" method. I don't know how to fix. I am looping through the array of contact indexes for as many contacts represented by the "friendsCount variable. Please help me fix the searchContact method. Thank you.  ContactsManager class  public class ContactsManager {      // Fields     Contact [] myFriends;     int friendsCount;      // Constructor     ContactsManager() {         this.friendsCount = 0;         this.myFriends = new Contact[500];     }      // Methods     void addContact(Contact contact) {         myFriends[friendsCount] = contact;         friendsCount++;     }      Contact searchContact(String searchName) {         for(int i = 0; i < friendsCount; i++) {             if(myFriends[i].name.equals((searchName))) {                 return myFriends[i];             }         }         return  null;     } }   Contacts class  public class Contact {      String name;     String email;     String phoneNumber;  }   Main class  public class Main {      public static void main(String[] args) {         ContactsManager myContactManager = new ContactsManager();          Contact con1 = new Contact();         con1.name = "Albert";         con1.phoneNumber = "9545899977";          myContactManager.addContact(con1);          Contact con2 = new Contact();         con1.name = "Jason";         con1.phoneNumber = "9545899944";          Contact con3 = new Contact();         con1.name = "Larry";         con1.phoneNumber = "9545899911";          Contact con4 = new Contact();         con1.name = "Mary";         con1.phoneNumber = "9545899933";          Contact con5 = new Contact();         con1.name = "Saraht";         con1.phoneNumber = "9545899900";          myContactManager.addContact(con2);         myContactManager.addContact(con3);         myContactManager.addContact(con4);         myContactManager.addContact(con5);          System.out.println(myContactManager.searchContact("Jason"));     } }


invoke setOnPreferenceChangeListener on Null reference object

Here is the complete error log  03-27 08:08:30.264 D/SubSettings( 7079): Launching fragment com.sakura.settings.fragments.BatterybarSettings 03-27 08:08:30.275 D/AndroidRuntime( 7079): Shutting down VM 03-27 08:08:30.275 E/AndroidRuntime( 7079): FATAL EXCEPTION: main 03-27 08:08:30.275 E/AndroidRuntime( 7079): Process: com.android.settings, PID: 7079 03-27 08:08:30.275 E/AndroidRuntime( 7079): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.android.settings/com.android.settings.SubSettings}: java.lang.NullPointerException: Attempt to invoke virtual method 'void androidx.preference.Preference.setOnPreferenceChangeListener(androidx.preference.Preference$OnPreferenceChangeListener)' on a null object reference 03-27 08:08:30.275 E/AndroidRuntime( 7079):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3270) 03-27 08:08:30.275 E/AndroidRuntime( 7079):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409) 03-27 08:08:30.275 E/AndroidRuntime( 7079):     at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) 03-27 08:08:30.275 E/AndroidRuntime( 7079):     at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 03-27 08:08:30.275 E/AndroidRuntime( 7079):     at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 03-27 08:08:30.275 E/AndroidRuntime( 7079):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016) 03-27 08:08:30.275 E/AndroidRuntime( 7079):     at android.os.Handler.dispatchMessage(Handler.java:107) 03-27 08:08:30.275 E/AndroidRuntime( 7079):     at android.os.Looper.loop(Looper.java:214) 03-27 08:08:30.275 E/AndroidRuntime( 7079):     at android.app.ActivityThread.main(ActivityThread.java:7355) 03-27 08:08:30.275 E/AndroidRuntime( 7079):     at java.lang.reflect.Method.invoke(Native Method) 03-27 08:08:30.275 E/AndroidRuntime( 7079):     at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:491) 03-27 08:08:30.275 E/AndroidRuntime( 7079):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930) 03-27 08:08:30.275 E/AndroidRuntime( 7079): Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void androidx.preference.Preference.setOnPreferenceChangeListener(androidx.preference.Preference$OnPreferenceChangeListener)' on a null object reference 03-27 08:08:30.275 E/AndroidRuntime( 7079):     at com.sakura.settings.fragments.BatterybarSettings.onCreate(BatterybarSettings.java:110) 03-27 08:08:30.275 E/AndroidRuntime( 7079):     at androidx.fragment.app.Fragment.performCreate(Fragment.java:2596) 03-27 08:08:30.275 E/AndroidRuntime( 7079):     at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:831) 03-27 08:08:30.275 E/AndroidRuntime( 7079):     at androidx.fragment.app.FragmentTransition.addToFirstInLastOut(FragmentTransition.java:1197) 03-27 08:08:30.275 E/AndroidRuntime( 7079):     at androidx.fragment.app.FragmentTransition.calculateFragments(FragmentTransition.java:1080) 03-27 08:08:30.275 E/AndroidRuntime( 7079):     at androidx.fragment.app.FragmentTransition.startTransitions(FragmentTransition.java:119) 03-27 08:08:30.275 E/AndroidRuntime( 7079):     at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManagerImpl.java:1853)   I am unable how should I initialize onPreferenceChangeListener, I also tried looking for code references to other places but couldn't figure out how they are initializing it. My whole code is at .   Thanks a lot in advance.


I have submitted a paper for a conference organized by the IRES. (details here: ) they accepted my paper within one day and instructed me to register. How will I know it is scam or not? Thanks in advance!


What is the probability of getting sum exactly n as total for throwing x dice?

"What is the probability of getting sum exactly 420 as total for throwing 100 dice?" is the actual question. But maybe I can modify it as title?  Just give me directions by which I can be able to solve the problem. How can we calculate such probability of large dices? Do I need to go with theoretical probability to solve it?


How to prevent LaTeX from line-breaking a phrase?

How can I prevent LaTeX from putting line-breaks into a phrase?  I could replace dashes with  and spaces with non-breaking spaces, but I'm looking for a more general solution in case I need other characters in such phrases.


Any number coprime with 10 dividing at leat one number of the form 111...111

How can I prove that any number coprime with 10 (either prime or not) can divide at least one number of the form 111...111?


A very quick way to prove a set is measurable.

All examples of non-measurable subset of $\mathbb{R}$ (in the Lebesgue sense) seem to need the axiom of choice in some way or the other. Hence, can we say:     The set $A\subseteq \mathbb{R}$ is measurable because the axiom of choice was not used to define it.   Is that a valid argument? Or does there exist non-measurable sets that do not require the axiom of choice?


Fully charged MacBook Air turns off when power cord removed

I have a MacBook Air, 2009, with a recently replaced Apple battery in December 2012. Recently, when power cord comes off, the computer shuts down. Also, it usually will not restart unless power cord is attached.


I am not sure if the title is correct, my problem is that I have a class and functions inside it, I would like to check if the value for the function is set and if not set other value  class some_class {     private $width;      function width( $value )     {         // Set another default value if this is not set         $this->width = $value;     } }  $v = new some_class();   // Set the value here but if I choose to leave this out I want a default value $v->width( 150 );


Is it considered good practice to edit region based spellings?

Recently I've noticed that some of my questions/answers on various communities have been edited for reasons such as "spelling mistakes".  They've included things such as changing "initialise" to "initialize" and other things in that nature.  As I am from Ireland and speak Irish English, which is more or less the same as British English, the words I am typing are correct. Side note: even as I typed "initialize" in that earlier example - the z version is underlined in red to show an error.  Am I in the wrong here and should I be using American spellings for Stack Exchange communication or are those people just a bit narrow minded?


How to change text to bold when font does not support bold

I have a 100 page document, I used colored text many places to highlight with below command in my preamble  \newcommand\bluetext[1]{\textcolor{blue}{#1}}   its working great however did not realize at the time of writing that i would require color printer for this. I wanted to change colored text to bold - I change the above command as below    \newcommand\bluetext[1]{\textbf{#1}}   It removed the colors but did not give me any bold letters, is it because of the font? or I am doing anything wrong? I am using sanskrit 2003 font.    In the attached image all the circled text should have appeared bold.  Thanks for your help - Here is the MWE  \documentclass[24pt]{article} \usepackage{fontspec} \usepackage{polyglossia} \usepackage{color} \usepackage{amstext, amsmath} \setmainfont[Script=Devanagari]{Sanskrit2003} \setdefaultlanguage{sanskrit} \newcommand\bluetext[1]{\textcolor{blue}{#1}}  %\newcommand\bluetext[1]{\textbf{#1}} % Blue Text \begin{document} १.१.१\bluetext{वृद्धिः}\textsuperscript{१/१} आत्\textsuperscript{१/१} ऐच्\textsuperscript{१/१}     \\ १.१.२     अत्\textsuperscript{१/१}  एङ्\textsuperscript{१/१} गुणः\textsuperscript{१/१}     \\ १.१.३     \bluetext{इकः}\textsuperscript{६/१} \bluetext{गुणवृद्धी}\textsuperscript{१/२}    \\  १.१.४     \bluetext{न}\textsuperscript{०/०} धातुलोपे\textsuperscript{७/१} आर्धधातुके\textsuperscript{७/१}    \\ १.१.५     क्क्ङिति\textsuperscript{७/१} च\textsuperscript{०/०}     \\ \end{document}


How do I find and remove any rule or newline in an output?

I have written an app to compare the response I get for a request with its standard response. If they differ I need to find the difference. Since the response I get for the request has \r and \n in between it doesn't match with the standard response even though the responses are the same.How do I remove these \r and \n which are in the response string I get? Please advice.  <R> <T>Expired</T> <K>Service</K> <E></E> <S>0,license </S> </R>


Merging two incoming broadband lines for faster Internet

We have a broadband line coming into our building which delivers around 8-10Mbps, which is okay but not great. Fiber is available in our area (30-100Mbps) but it's not available where we are just yet.   Is there some way we could connect two lines (which we would take from two different providers so we would have redundancy if one failed) and merge them into one signal which we could distribute?  Is there some sort of setup that can do this?  Of course we have the option of a leased line but for 12Mbps symmetrical upload/download we'd be looking at around £500 per month compared to £15 per month for normal or fiber broadband.  I made a small pseudo flow chat of the setup below:


Prove $n^{\aleph_0} =c= \aleph_0^{\aleph_0}$

This is an exercise I'm trying to solve. My attempt $$c=2^{\aleph_0}\leq\aleph_0^{\aleph_0}\leq (2^{\aleph_0})^{\aleph_0}= 2^{\aleph_0\cdot\aleph_0}=2^{\aleph_0}=c$$ So all values in the inequality are equal and $c= \aleph_0^{\aleph_0}$ But I don't know how to prove $n^{\aleph_0}=c$ I would like a similar approach to the one I made (if it's valid :/ ) Thank you!


What is the purpose of this 4-pin interface on SATA HDDs and why doesn't it exist on SSDs?

I have 4 HDDs here with me, from 3 different manufacturers, and all of them have the following 4-pin extra interface beside the SATA connector:    Looking on internet, I can see that it exists on all HDD devices, but not on SSDs:    On old IDE devices there was a similar interface used to select operational mode(master/slave), but on SATA it doesn't makes sense any more.... So, could someone tell me what this interface is intented to do and why it doesn't exists on SSDs? It is used on any practical situation?


Where should I ask Node.js related questions?

Where should I ask Node.js or anything related to server-side JavaScript questions?   Can anyone suggest me the right place?


Is Gravity a part of the Strong Nuclear Force?

In episode 7 season 5 of Through the Wormhole, they say that gravity could just be a manifestation of the strong nuclear force and that the force carrier are a pair of Gluons. Is this valid in anyway?


Find all $n>1$ such that $\dfrac{2^n+1}{n^2}$ is an integer.   I know that $n$ must be odd, then I don't know how to carry on. Please help. Thank you.


can I get Windows 10 over Ubuntu because I have Ubuntu and I want Windows back

Right now I have Ubuntu 15.10 and I want to get Windows 10 on it. I don't want it in a window on Linux. I want it so that when I turn my computer on it is there. I have the ISO right now what do I do? Windows 10 is free so I don't need the key for so I don't have to buy a new windows. I have look at all the question people have said and the answers are not helping. (don't care about the GUI for booting to Linux)


I am trying to get a math beamer presentation to work and it seems that cleveref is causing problems. The MWE below gives the error   Paragraph ended before \@ynthm was complete   In the documentation of cleveref, one finds the following remark:     The beamer document class rededefines the \label command in a   particularly devious way that breaks cleveref's optional argument to   that command.   What optional argument?  Does that mean that cleveref and beamer are simply incompatible? Is there any way around that problem?  MWE:  \documentclass{beamer}  \makeatletter \let\th@plain\relax \makeatother  \usepackage{ntheorem} \usepackage{cleveref}  \theoremstyle{plain}  \newtheorem{MainThm}{Main Theorem}  \crefname{MainThm}{Main Theorem}{Main Theorems}  \mode<presentation>{\usetheme{Frankfurt}}  \begin{document} \begin{frame}{Test}     \begin{MainThm}         blabla     \end{MainThm} \end{frame} \end{document}


Very interesting method for multiplication of natural numbers

In some book I saw this example on how to multiply numbers $83$ and $157$.  $$83 \qquad 157$$ $$41 \qquad 314$$ $$20 \qquad 628$$ $$10 \qquad 1256$$ $$5  \qquad 2512$$ $$2  \qquad 5024$$ $$1  \qquad 10048$$  The procedure is that in the left column we divide numbers by two and write down the result under the number we divided (if the number is odd then we take integer which is closest to the result and less than the result) and we repeat the procedure until we arrive at the number one.  In the right column we just take the next number to be twice as big as the previous one.  Now we look at the two columns and discard those numbers in the right column if they correspond to the even number in the left column, so we discard $628$ and $1256$ and $5024$.  If we now add the remaining numbers in the right column we obtain $157+314+2512+10048=13031$ but $13031=83 \cdot 157$.  So my questions would be:  1) Does this method works for every two natural numbers $m,n$?  2) Can someone explain why this method works?


My F statistic is really high - what does this mean?

Source |       SS       df       MS              Number of obs =     300 -------------+------------------------------           F(  5,   294) =16580.50        Model |  1.1499e+10     5  2.2998e+09           Prob > F      =  0.0000     Residual |  40778600.2   294  138702.722           R-squared     =  0.9965 -------------+------------------------------           Adj R-squared =  0.9964        Total |  1.1540e+10   299  38593905.2           Root MSE      =  372.43   Should I be worried about this- does your F statistic size matter?  How do i find out what the p value of my model is - is it the p value attached to _cons in the bottom of my coefficients?  what do i test this F stat against and what warrants significance?


Disable three-letter pings from chat to save Oliver, Olivier and Olive from Oli's pings

So apparently there's a feature (undocumented or otherwise) that allows you to ping people based on the first three letters of their name. I guess I can sort of see what went through its developer's mind but it causes a problem.  My name is Oli. It's short for Oliver. In the Ask Ubuntu chat room, we've recently had three people who match the @Oli ping, me and two with longer names that start "Oli". There are hundreds of people like this in the network.  So when somebody talks to me, they get pinged too. I'm a moderator so people talk to me quite a lot. That means it's got to be pretty hellish if your nick starts with "oli". You're getting loads of pings that aren't actually for you.  In reflection (given that there's tab completion), this is a stupid feature. It should be taken out back and shot.    This appears to have  and got a slight fix but has that since regressed? Today an Oliver was getting pings for me so the full-word-match thing advertised in the answers isn't catching any more.  And in terms of making tab-completion a viable option (not all people know about it, not all people have tab keys, eg phones), how about that if you write a possibly ambiguous @name:   It works out who based on who's chatting, and/or Offers the user an option for each ambiguous @name used so only the correct people are ever pinged. Or something similar as the username is tapped in...


I got the difference between polar vectors and axial vectors (pseudovectors).   An example of pseudovector is $\mathbf{B}$. But why exactly the magnetic field is a pseudovector and its components parallel to an coordinate axis do no change signs if I reverse that axis?


whats the lim$\left(2^n+3^n\right)^{\frac{1}{n}}$ of this sequence to infinity?

lim$\left(2^n+3^n\right)^{\frac{1}{n}} $   I set  $y=$lim$\left(2^n+3^n\right)^{\frac{1}{n}} $  ln$(y)=$  lim  $(1/n)$  ln$(2^n+3^n) $  and I get zero  multiplied with  infinity.  How should i proceed? Tips are  welcomed as well


Say, there's a Java (C#, Javascript, etc) question involving array and tagged only 'java'. Two months ago nobody would lift a finger to add 'arrays' tag: the benefit is tiny, if it exists at all.  Yet, last few days I've been noticing a lot of such edits and not sure what to do. Some users even go on retagging rampage, updating every question they can lay their hands on (you can see them repeatedly in the list of pending edits).  I don't mind those guys getting their lousy 1000 reputation this way (well, only a little), but somehow I feel that the system was intended for slightly more substantial changes.    What would you do in this case? Approve or reject?  PS Some examples from the last few minutes


Let $d \in \mathbb{Z} \setminus \{0, 1\}$ square free, $K = \mathbb{Q}(\sqrt{d})$, $\mathcal{O}_K$ the corresponding ring of integers, $\mathfrak{a} \subseteq K$ a fractional ideal $n, n' \in \mathbb{N}$ with $n\mathfrak{a}, n'\mathfrak{a} \subseteq \mathcal{O}_K$.   I'm currently trying to prove that the definition of the idealnorm for fractional ideals is well defined. Inside this proof I need the following result: $[n\mathfrak{a} : nn'\mathfrak{a}] = [\mathcal{O}_K : (n')]$ or more general $n\mathfrak{a} / nn'\mathfrak{a} \cong \mathcal{O}_K / (n')$ as abelian groups.  I don't know how I could approach this step. Any help is welcome!  Duplicate claim: My proof looks similar to the one posted , but the linked post doesn't prove the question I asked here.


What's the difference between point and shoot camera brands?

Our old camera broke, so we decided to buy a new one, but we can't choose between similar models from Fujifilm, Canon, and Nikon. Many people advised me to get the Canon, but in my opinion the Fujifilm looks better. What's the difference between these brands, and in general is there a particular reason I should pick one over another?


The set of integers is not open or is open

Baby Rudin gives the example of the set of all integers being not open if it is a subset of $\mathbb{R}^2$.  If we consider the set of integers in $\mathbb{R}$, is this set also not open? I can find a neighbourhood which will contain any point, $p$, however is it a requirement that a neighbourhood contains more than one point?  I'm trying to understand this fully and have searched through the various posts that have a slight relation and can not find out specifically how these take interior and isolated points into account and how these relate to openess.


Speak in games via the Kinect with Xbox One

Is it possible to hear / speak to lobby chat and my teammates mid-game via the Kinect? I'm not wearing headphones and I'm not in a party.


Finding points on a line a given distance from a given point

The line $l$ has gradient $-2$ and passes through $A=(3,5)$. $B$ is a point on $l$ such that $\overline{AB}=6\sqrt5$. Find coordinates of each possible points of $B$.   There are two $x$-coordinates and two $y$-coordinates and so far I have got to $(3-x)^2+(5-y)^2=180$. What do I do from here?


File cannot be deleted due to being used by System

I have a file I can't delete as "it is used by System". I tried rebooting, turning off and on, then I tried using Revo Uninstaller forced delete and FileAssassin, but none of them worked. I checked if it was a virus using ESET 9 but the file is not infected, it is just "used by System" and cannot be deleted. Any ideas on removing that file?   EDIT: I'm using Windows 10 64 bit. The file itself is a file I made into a .bin some time ago, nothing important. I did close Daemon of course, still no clue why System uses it.


Prove that $\sin x + 2x \ge \frac{3x.(x+1)}{\pi} $

Prove that $$\sin x + 2x \ge \frac{3x.(x+1)}{\pi}\quad\forall x \in   \left[0,\frac{\pi}{2}\right].$$  My work: $$ 3x^2 + (3-2\pi )x  - \pi \sin x \le 0 $$ $$ f(x) = 3x^2 + (3-2\pi )x -\pi \sin x $$ $$f(0)=0 $$ $$f\left({\pi\over 2 }\right) ={\pi\over 2 }\left(1 -{\pi\over 2 } \right)$$  What should I do next ?


Doesn't receive email from other mail servers

I really need your help. I am trying to set up first time my own mail server using Postfix, Dovecot IMAP/POP3 and MySQL backend on a Ubuntu server. I can successfully receive and send mail to my local server, However I can only send mail to to other mail servers like gmail and outlook but unable to receive. and always get this  The recipient server did not accept our requests to connect. Learn more at  [xyz.example.com. xxx.xxx.xxx.xxx: timed out]  my domain is something like xyz.example.com not www not mail.example.com I have used dig MX xyz.example.com which produce ;; ANSWER SECTION: xyz.example.com.     60      IN      MX      60 xyz.example.com.  However when I try mxtoolbox.com to test smtp  SMTP Connect Failed To Connect More Info Session Transcript: Connecting to xxx.xxx.xxx.xxx Connection attempt #1 - Unable to connect after 15 seconds. [15.05 sec]  I have also tried telnet xyz.example.com 25  along with 465, 587, 993, 995 Trying 123.345.567.789. Connected to xyz.example.com. Escape character is '^]'. 220 xyz.example.com ESMTP Postfix (Ubuntu)  When I tried telnet externally  couldn't open connection to the host, on port 25: connect failed"  My domain is certified but I am using openssl certificate for encryption. I don't know what I am doing wrong, please guide me and help me out. Thanks in advance


I was dual-booting Windows 7 and Linux Ubuntu on my desktop, and today is the day they gave out free Windows 10 upgrades.  How exciting!  I got the update, and it was installing, and I left to go take a 30 minute nap.  However, when I came back to my computer, it led me to the grub rescue prompt.  error: no such partition. Entering rescue mode... grub rescue>   I get the following when I type ls:  grub rescue> ls (hd0) (hd0,msdos5) (hd0,msdos3) (hd0,msdos2) (hd0,msdos1)   After a quick look through of people who encountered the grub rescue prompt, I typed set and got the following  grub rescue> set cmdpath=(hd0) prefix=(hd0,msdos6)/boot/grub root=hd0,msdos6   I was still kind of lost after finding that certain commands like normal didn't work, and then I found a video tutorial where you boot from a Linux image cd and run some commands on the terminal.  Luckily, I had my CD with me, and booted from there.  When I typed sudo fdisk -l into the terminal however, this is what I got:  ubuntu@ubuntu:~$ sudo fdisk -l  Disk /dev/sda: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xc03ede74     Device Boot      Start         End      Blocks   Id  System /dev/sda1   *        2048      206847      102400    7  HPFS/NTFS/exFAT /dev/sda2          206848  1547022335   773407744    7  HPFS/NTFS/exFAT /dev/sda3      1547022336  1547943935      460800   27  Hidden NTFS WinRE /dev/sda4      1547945982  1953521663   202787841    f  W95 Ext'd (LBA) /dev/sda5      1915731968  1953521663    18894848    7  HPFS/NTFS/exFAT   Says here none of my devices has the Linux system in them!  And I couldn't follow the video tutorial any more than that...  I teased my brain a little and determined that sda2 contained my Windows system (since I remember my C: drive has around 700-ish GB of space).  After thinking a little bit more, I remember assigning around 200-ish GB of my hard disk space to something that's Ubuntu related when installing Ubuntu.  I don't exactly remember which, but I think it was basically Ubuntu "hard disk space", and it didn't have any boot files in them.  I assigned two other things for linux, but they were very small in size (not breaking the 1 GB mark yet).  So, can anyone here help me out get my upgrade back on track?  I won't mind if I end up having to completely remove the partitions that have Linux in them.


I'm checking a technical paper submission and came across the phrase          We propose spherical Gaussian based approximations to calculate this analytically.      and wondering if this needs a hyphen or not. I'm inclined towards          spherical Gaussian-based      but could it also be           spherical-Gaussian-based      which is what some of the other questions on hyphenation here are based on.


C++ undefined reference to member of generic class

I am new to C++ and got this error for hours and I hope someone can help me with this.  So basically I have got 2 classes: Matrix,DenseMatrix with DenseMatrix being the subclass of Matrix.    For some simple mathematical operations like adding two matrices which are always the same for any type of matrix, I wanted to implement a function in the class Matrix.   T &mul(const Matrix &other);   The idea is that calling mul on a subclass (e.g DenseMatrix), the result will also be a DenseMatrix. However the other matrix does not need to be the same class, just any subclass of Matrix. That's why I use generic types and my classes are defined like this:  class DenseMatrix : public Matrix<DenseMatrix> class OtherMatrix: public Matrix<OtherMatrix> class OtherMatrix2: public Matrix<OtherMatrix2> ...   So that calling mul will return a matrix of the same type and the argument is simply a Matrix without diamond-brackets.  Now the Problem is that I am getting the following error:  DenseMatrix mat{6,6}; DenseMatrix mat2{6,6}; mat.add(mat2);  >>> undefined reference to `Matrix<DenseMatrix>::add(Matrix<DenseMatrix> const&, int)'   I was thinking that maybe I need to introduce a second generic type for the argument of the function but I am not sure how to do this.  I am very happy if someone could help me with this one.    Matrix.h:  template <typename T> class Matrix {     T &add(const Matrix &other, int threads = 1); }   Matrix.cpp:  #include "Matrix.h" template<typename T> T &Matrix<T>::add(const Matrix &other, int threads) {     std::cout << "ADDING";     return *this; }   DenseMatrix.h:  class DenseMatrix : public Matrix<DenseMatrix> {   }


Same strings, but from different sources. How to correctly compare?

I have a string:  java.lang.IllegalArgumentException: local part cannot be "null" when creating a Qname   which I'm pulling from a log file on a unix server.   and I have this same exact string which I'm pulling from a windows .txt file to compare against the string from the unix server:  java.lang.IllegalArgumentException: local part cannot be "null" when creating a Qname  I'm trying to determine if they are equal, but the .equals() method in java is letting me know that they are not equal.   How can I go about determining that they are indeed equal?


Does the sequence $(\sqrt{n} \cdot 1_{[0, 1/n]})_n$ converge weakly in $L^2$?

Let $f_n (x) = \sqrt n 1_{[0,1/n ] } (x) \in L^2 (\mathbb R)$. Does $f_n$ converges weakly to $0$ in $L^2$?  I tried to prove it by using Hölder's inequality or the Lebesgue differentiation theorem, but neither seems to work. I also can't find a counter example. Any help is appreciated.


def fib(N):     if N <= 1:         return N     return fib(N-1)+fib(N-2)   I cannot calculate the Big-O for this function, anyone can help me using math method. Thanks！


"Series" – a noun of multitude similar to "lot", "majority", "percentage", "proportion"– verb agreement

According to Garner's fourth edition  Though serving as a plural when the need arises, series is ordinarily a singular noun. But it is also a noun of multitude, so that phrases such as a series of things take a plural verb. However, the collocation there {has been - is} a series has predominated in print sources. Common nouns of multitude: lot, majority, mass, minority, multitude, percentage, proportion, variety.  However,  reads  When it has the singular sense of "one set," it takes a singular verb, even when series is followed by of and a plural noun: A series of lectures is scheduled.  Are these dissimilar usages stylic advice? Secondly, the inversion after there also chooses singular elsewhere; why is it so?  When the verb precedes the noun percentage, a singular verb is required. That is, a higher percentage of them are, but there is a higher percentage of them.


Bone Heat Weighting: failed to find solution for one or more bones (automatic weight painting error)

I was attempting to make an animatable 'humanoid' rig with rigfy. However I have ran into a problem that I am unable to find any solutions to. Bone Heat Weighting: failed to find solution for one or more bones Without Rigfy: Front:  Side:  With Rigfy: Front:  Side:


Why is the expected value $E(X^2) \neq E(X)^2$?

I wish to use the  to calculate the variance of a normal-distributed function. For this, I need the expected value of $X$ as well as the one of $X^2$. Intuitively, I would have assumed that $E(X^2)$ is always equal to $E(X)^2$. In fact, I cannot imagine how they could be different.  Could you explain how this is possible, e.g. with an example?


Approaches for Real time copy of database on same SQL Server instance

I have a draft of requirements that look like this:   Production database should be copied in real-time to "Pre-prod" database The Pre-prod database should be available to read and update It should be possible to make schema and data changes to Pre-Prod Schema and data changes on Pre-prod should not effect Prod   The databases will be on the same SQL Server instance.  I'm wondering what approach to take? Transactional Replication seems the best option, but applying schema changes to a subscriber seems like a recipe for disaster.  Mirroring is out because the mirror will not be available; log shipping is out for similar reasons.  Are there any other technologies I should be considering?


Proving the open interval $(0,1)$ is uncountable

I am currently able to prove this statement using the Cantor diagonalisation argument, my question is whether there is another way (more simple or more complex) to prove this statement, without diagonalisation?


I imported my shapefile dat to R with readOGR, coordinates are given in easting and northing, I'd like to change it to latlon and tried:  dat_latlon <- spTransform(dat, CRS("+proj=longlat +datum=WGS84"))   However, I get this error message:  Error in spTransform(xSP, CRSobj, ...) :    No transformation possible from NA reference system   And str(dat) shows that:    ..@ proj4string:Formal class 'CRS' [package "sp"] with 1 slots   .. .. ..@ projargs: chr NA   So I guess I have to assign the projection first? Somewhere here (or stackoverflow) I found this:  dat@proj4string <- "+proj=tmerc +lat_0=0 +lon_0=9 +k=1 +x_0=3500000 +y_0=0 +datum=potsdam +units=m +no_defs"   but I only get an error:  Error in checkAtAssignment("SpatialPointsDataFrame", "proj4string", "character") :    Zuweisung eines Objektes der Klasse “character” ist für @‘proj4string’ in einem Objekt aus Klasse “SpatialPointsDataFrame” nicht zulässig; is(value, "CRS") ist nicht TRUE   (sorry for German - apparently it's not valid to assign an object of class character in an object of class SpatialPointsDataFrame).  Now I am stuck, can you help me?


I remember seeing an upper bound for the binomial $\binom{n}{k}$ with an exponential function, something like $\binom{n}{k}\leq \left(ne/k\right)^k$. What exactly is it, and are there other similar good upper bounds for $\binom{n}{k}$?  Edit: As the link in Macavity's comment shows, the bound is indeed $\binom{n}{k}\leq \left(ne/k\right)^k$. How can we prove this?


tikz: Distribute evenly and randomly circles

I want to fill a part of a picture with more or less evenly and randomly distributed circles which should not overlap. It would be okay if circles are only partly inside the shape.  The density should be like what you see on this page  with values 80-100. (But I do not need so many circles, 30 should be enough, I could repeat the pattern).   I cannot use a grid and "wobble" the circles a bit: The circles are too large and it simply does not look randomly.   Currently I am thinking about a random attempt: Get some random point, measure its distance to existing circles, either paint or throw the point away. Try 100 times and hope that you get the right number of circles (and that it does not take too long). But perhaps someone has a better idea.   The example draws the circles simply manually:  \documentclass{article} \usepackage{tikz} \usetikzlibrary{backgrounds} \begin{document}   \begin{tikzpicture}[framed,gridded,radius=0.5cm]  \draw[red](0,0) rectangle (5,5);   \draw (1,1) circle;   \draw (2.3,1.1) circle ;   \draw (4.5,0.8) circle ;   \draw (5.1,1.8) circle ;   \draw (0.4,3.3) circle ;   \draw (2.1,2.8) circle ;   \draw (3.8,3.5) circle ;   \draw (4.8,4.2) circle ;   \draw (0.8,4.9) circle ;   \draw (2.1,4.1) circle ;   \draw (3.8,2.0) circle ;   \draw (3.5,0.6) circle ;   \draw (3.0,5.0) circle ;      \draw (4.1,5.1) circle ;             \draw (0.9,2.1) circle ;  \end{tikzpicture}  \end{document}


PHP: Write Non ASCII Characters got from HTML form to a file with PHP

I'm programming a quite simple PHP Script, that writes a string (sentence) gotten from an HTML FORM into a file. This string sometimes contains Non-ASCII Characters, in my case german umlauts, äöü. But instead of writing them to the file correctly it just writes little question-mark-symbols. How can I fix that?   <?php header('Content-type: text/html; charset=utf-8');   #   $_POST["message"] #   $_POST["random"] #   $_POST["date"]  #$MESSAGE = utf_encode($_POST["message"]);  $countfile = fopen("filecount", "r");  $filecount = fread($countfile,filesize("filecount")); fclose($countfile);   $filename = $filecount + 1; echo($filename);  if ($_POST["random"]){  $newmessagefile = fopen($filename, "w"); fwrite($newmessagefile, $_POST["message"]); fclose($newmessagefile);  $countfilew = fopen("filecount", "w"); fwrite($countfilew, $filename);  fclose($countfilew); }   else {      $newmessagefile = fopen($_POST["date"], "w");     fwrite($newmessagefile, $_POST["message"]);     fclose($newmessagefile);      $specialdaysfile = fopen("specialdays", "a");     fwrite($_POST["date"]);     fclose($newmessagefile);  }  ?>


Ubuntu 18.04.3 LTS  sudo apt-get upgrade -f Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done Calculating upgrade... Done The following packages were automatically installed and are no longer required:   python3.7-distutils python3.7-lib2to3 Use 'sudo apt autoremove' to remove them. The following packages will be upgraded:   libpython3.7-stdlib snapd 2 to upgrade, 0 to newly install, 0 to remove and 0 not to upgrade. 1 not fully installed or removed. Need to get 13.7 MB/15.4 MB of archives. After this operation, 1,700 kB of additional disk space will be used. Do you want to continue? [Y/n] y Get:1 http://ny-mirrors.evowise.com/ubuntu bionic-updates/main amd64 snapd amd64 2.42.1+18.04 [13.7 MB] Fetched 13.7 MB in 3s (4,641 kB/s) (Reading database ... 356632 files and directories currently installed.) Preparing to unpack .../libpython3.7-stdlib_3.7.5-2~18.04_amd64.deb ... Unpacking libpython3.7-stdlib:amd64 (3.7.5-2~18.04) over (3.7.4-1+xenial2) ... dpkg: error processing archive /var/cache/apt/archives/libpython3.7-stdlib_3.7.5-2~18.04_amd64.deb (--unpack):  trying to overwrite '/usr/lib/python3.7/distutils/__init__.py', which is also in package python3.7-distutils 3.7.4-1+xenial2 dpkg-deb: error: paste subprocess was killed by signal (Broken pipe) Preparing to unpack .../snapd_2.42.1+18.04_amd64.deb ... Unpacking snapd (2.42.1+18.04) over (2.40+18.04) ... Errors were encountered while processing:  /var/cache/apt/archives/libpython3.7-stdlib_3.7.5-2~18.04_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1)  sudo apt --fix-broken install Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following packages were automatically installed and are no longer required:   python3.7-distutils python3.7-lib2to3 Use 'sudo apt autoremove' to remove them. The following additional packages will be installed:   libpython3.7-stdlib The following packages will be upgraded:   libpython3.7-stdlib 1 to upgrade, 0 to newly install, 0 to remove and 0 not to upgrade. 2 not fully installed or removed. Need to get 0 B/1,745 kB of archives. After this operation, 94.2 kB disk space will be freed. Do you want to continue? [Y/n] y (Reading database ... 356635 files and directories currently installed.) Preparing to unpack .../libpython3.7-stdlib_3.7.5-2~18.04_amd64.deb ... Unpacking libpython3.7-stdlib:amd64 (3.7.5-2~18.04) over (3.7.4-1+xenial2) ... dpkg: error processing archive /var/cache/apt/archives/libpython3.7-stdlib_3.7.5-2~18.04_amd64.deb (--unpack):  trying to overwrite '/usr/lib/python3.7/distutils/__init__.py', which is also in package python3.7-distutils 3.7.4-1+xenial2 dpkg-deb: error: paste subprocess was killed by signal (Broken pipe) Errors were encountered while processing:  /var/cache/apt/archives/libpython3.7-stdlib_3.7.5-2~18.04_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1)  uname -a Linux user 4.15.0-70-generic #79-Ubuntu SMP Tue Nov 12 10:36:11 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux


Point in polygon algorithm for multiple polygons

I've a Google map with bunch of polygons on it.  Here is a problem I'm interested in: Given a lat,lng point, what's the best way to determine all the polygons that this point lies in?  The obvious way is to run a "point in polygon" algorithm iteratively for each polygon, but I was wondering if there an efficient algorithm to answer such queries especially if you have thousands of polygons.


how to fix java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Boolean' on a null object reference

java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Boolean com.pregbodan.preglogistics.DBHelper.checkusername(java.lang.String)' on a null object reference i keep getting this error on this page     reg_btn.setOnClickListener(new View.OnClickListener() {             @Override             public void onClick(View v) {                 final String fullname, email, username, password, verpassword;                 fullname = String.valueOf(reg_name.getText());                 username = String.valueOf(reg_username.getText());                 email = String.valueOf(reg_email.getText());                 password = String.valueOf(reg_password.getText());                 verpassword = String.valueOf(reg_verpassword.getText());                  if (email.isEmpty()) {                     reg_email.setError("Please enter email id");                     reg_email.requestFocus();                 } else if (password.isEmpty()) {                     reg_password.setError("Please enter your password");                     reg_password.requestFocus();                 } else if (fullname.isEmpty()) {                     reg_name.setError("Please enter your password");                     reg_name.requestFocus();                 } else if (verpassword.isEmpty()) {                     reg_verpassword.setError("Please enter your password");                     reg_verpassword.requestFocus();                 } else if (username.isEmpty()) {                     reg_username.setError("Please enter your password");                     reg_username.requestFocus();                 } else if (username.equals("") || password.equals("") || email.equals("") || fullname.equals("") || verpassword.equals(""))                     Toast.makeText(register.this, "Please enter all the fields", Toast.LENGTH_SHORT).show();                 else {                     if (password.equals(verpassword)) {                         Boolean checkuser = DB.checkusername(username);                         if (checkuser == false) {                             Boolean insert = DB.insertData(username, password, fullname, email);                                 if (insert == true) {                                     Toast.makeText(register.this, "Registered successfully", Toast.LENGTH_SHORT).show();                                     Intent intent = new Intent(getApplicationContext(), MainActivity.class);                                     startActivity(intent);                             } else {                                 Toast.makeText(register.this, "Registration failed", Toast.LENGTH_SHORT).show();                             }                         } else {                             Toast.makeText(register.this, "User already exists! please sign in", Toast.LENGTH_SHORT).show();                         }                     } else {                         Toast.makeText(register.this, "Passwords not matching", Toast.LENGTH_SHORT).show();                     }                 }             }         });


Question about Maximum Modulus Principle

Let $f_1, f_2, \ldots ,f_n$ be holomorphic functions on a region $\Omega$. Show that if $\phi (z)=|f_1(z)|+|f_2(z)|+\ldots +|f_n(z)|$ attains a maximum value on $\Omega$, then $f_i$ is constant for each $i=1,\ldots ,n$.


Is accessing a bool field atomic in C#? In particular, do I need to put a lock around:  class Foo {    private bool _bar;     //... in some function on any thread (or many threads)    _bar = true;     //... same for a read    if (_bar) { ... } }


Do spells cast through magic items require expensive material components?

I have a Staff of the Woodlands, which allows me to cast the spell Awaken. Awaken has an expensive material component of "an agate worth at least 1,000 gp, which the spell consumes". Is that agate required and consumed when Awaken is cast through the Staff, or does casting it through the Staff somehow modify or remove that requirement?


Tangents are drawn from the point ($\alpha$,$\beta$) to the hyperbola  $3x^2 - 2y^2 = 6 $ and are inclined at angles A and B to the x -axis. If $\tan A. \tan B = 2$, prove that $\beta^2$=2$\alpha^2$ - 7.  I tried the following concept,The points on Hyperbola from where tangent are drawn are $(\sqrt2*(\sec A),\sqrt3*(\tan A))$ &  $(\sqrt2*(\sec B),\sqrt3*(\tan B))$   The two tangents are $\frac{\sec A}{\sqrt2}$-$\frac{\tan A}{\sqrt3}$=1 and  $\frac{\sec B}{\sqrt2}$-$\frac{\tan B}{\sqrt3}=1$, I tried entering ($\alpha$,$\beta$) and using condition $\tan A. \tan B = 2$ but not able to get the result $\beta^2$=2$\alpha^2$ - 7.


Why we mutilply wavefunction with conjugate of it to obtain the probablity density of particle?


Time dilation in outer space vs in a gravitational field?

I have been wondering how could aging process differ for a person moving close to velocity of light or for a person close to a very strong gravitational field compared to a person who is in a slow motion. This indicates that molecular reactions happening in our body slows down when you move closer to velocity of light? And if so how is that possible?


If U is a T-invariant subspace of V is there necessarily another T-invariant subspace$-W S.T. U\oplus W = V?$

Suppose $V$ is a vector space over $\Bbb F, T:V\to V$ is a linear operator  and $U$ is a T-invariant subspace of V. is there necessarily another T-invariant subspace$-\,W\,\,  S.T. \,U\oplus W = V?$   I suspect this is in fact not true but cannot come up with a counter example.


Netflix not working on Ubuntu 19.10 with Chromium

I have not much do add to the title, for some reason works with Firefox but not with Chromium and I would like to fix it. I searched on the web and seems I'm not the only one but found not good answer, not one at least that fixed my problem. I red that could be something related to DRM content reproduction on the browse. I red  question but no solution for me.


Words like 'disgruntled' with no positive counterpart

"I was thoroughly gruntled."  Are there many words like 'disgruntled' where there is no positive counterpart? And was there ever a word 'gruntled'? And if not, where did 'disgruntled' derive from?


Will my coffee end up colder if I wait to put in the milk?

When I receive a cup of coffee, and I'm not yet ready to drink it, will it lose less heat if I immediately add the milk, rather than wait to add the milk just before I drink it?  (Bonus points for estimate of difference based on 5 minute wait!)


What's the real difference between a postdoc and a research fellow? (Which one is considered a 'better' experience?'

As the title suggests, it's not clear to me the actual difference between a postdoc and research fellow, especially when looking at the typical academia road. I understand that (maybe?) there is a difference between how the two are funded, but which one that (naturally) shows more qualities that can be appreciated when looking for a job as a lecturer? Qualities like 'Independent researcher that can design and lead high quality research programs'. Edit: If it helps, I am talking specifically about the UK system.


drupal_add_js not work in form validation failed

I add js file with drupal_add_js in hook_form_alter, it is ok and I see it in list of js loaded in page, but when I submit form and form not validate and return to that form (after validation failed) I don't see js files that added to form, why this happened? and how can add my js file in that form after validation failed ?   some part of my code   function mymodle_form_alter(&$form, $form_state, $form_id) {   if ($form_id == 'news_node_form') {     drupal_add_js(drupal_get_path('module', 'mymodule') . '/js/mymodulejsfile.js'); //, array('scope' => 'footer','weight' => 10));   } }   code work correctly in add and edit form, but when form submit and validation failed it show validation error but my js file not loaded in page (I checked html source and check firebug script files), but there is not my js file,


How can I run the Android emulator together with another VM?

Whenever I open an Android emulator when a different kind of VM is already running, I get the "usual" error messages:     emulator: Failed to sync vcpu reg   emulator: Failed to sync HAX vcpu context    it is recommended not to run another VM, but what if I need the another VM for development, or to run the server for my Android app on it? Is there a way to run a VirtualBox Linux guest VM and the Android emulator at the same time? My host OS is OSX if that matters.


In Python, how to set the proper context in order to set the strength of a sun lamp (in Cycles)?

I'm trying to use Python to create a sun lamp (in Cycles mode) and then change it's strength.  I began by performing the operations manually and then copying the Python code that was produced in the top output area.  When I then run the script, the sun lamp is created, but I get an error before the strength can be set.  Here's the code:  import bpy  bpy.context.scene.render.engine = 'CYCLES' bpy.ops.object.lamp_add(type='SUN', view_align=False, location=(0, 0, 0)) bpy.context.space_data.context = 'DATA' bpy.data.node_groups["Shader Nodetree"].nodes["Emission"].inputs[1].default_value = 2   Which produces this error:  File "/Text", line 5, in <module> AttributeError: 'SpaceTextEditor' object has no attribute 'context'   It seems as though the problem is that I'm not properly telling Blender what object I want to change?    The answer (thanks to poor):  import bpy    bpy.context.scene.render.engine = 'CYCLES' bpy.ops.object.lamp_add(type='SUN', view_align=False, location=(0, 0, 0)) bpy.context.object.data.node_tree.nodes['Emission'].inputs['Strength'].default_value=3


Is there an equation to calculate the average speed of liquid molecules?

I seem to remember from first year physics that we can calculate the RMS speed of a stationary, ideal gas with $v=\sqrt{\frac{3RT}{M}}$. Does a similar equation exist for liquids?


instant upload after select file in a file or image field (quit upload button)

In the normal fashion you have to select the file you want to upload in a file field or image field and then click "upload" button.  this is not very "user friendly"  How to upload the image or file just after the user selects it in the window without the necessity of click "upload" button.


PHP - Get substring after last occurrence of needle not including needle

If I have abcxyz.doc for example and want to return the extension minus the dot, so just doc as a substring. I cannot rely on the extension always being 3 chars.  <?php $x = 'abcxyz.doc'; ltrim(strrchr($x, '.'), '.');   Is this the best I can do, or is there a more elegant way to do this?


Why does this "common" idiom for thread-safe event-calling in C# works at all?

I'm reading Effective C# and I came across the following pattern to improve event-calling behavior and make it thread-safe:      public class EventSource {         private EventHandler<int> Updated;         private int counter;           public void RaiseUpdates(){           counter++;           var handler = Updated;           if (handler != null){               handler(this, counter);         }   The book claims that since there a "shallow copy" in the assignment to handler, the call handler(this, counter) will call all registered clients even if moments before one of them unsubscribed. But aren't delegates in C# reference types? Wouldn't this assignment just create a new reference for the underlying delegate object?


Is this request for proof of funds for Russian citizen legitimate?

I have a friend in Moscow who has paid for her trip to Australia.She has claimed that 2700 USD is required by the authorities (30 USD / day for a 90 day tourist visa) to support herself.  Now she wants to borrow this money from me. Is the proof of funds a legitimate requirement for Russian citizens? She claims to have gone through an agency.


A place in Pennsylvania with unknown projection

I have a shapefile with no projection. As a result, the (X,Y) coordinate cannot be understood.   This place is in south eastern Pennsylvania, and its longitude and latitude is about -75.2° and 40.1°. Can anyone guess its "projection coordinate" ? PS: I have asked  and the projection of that one is "Pennsylvania State Plane South (3702)". Unfortunately, It doesn't match this one.


Equivalences of definitions of submanifolds in $\mathbb{R^n}$

A subset $M \in \mathbb{R}^n$ is called a smooth k-dimensional submanifold of $\mathbb{R}^n$, $k \leq n$, if any point $x \in M$ has a neighborhood $O_x$ in $\mathbb{R}^n$ in which $M$ is described in one of the following ways:  (1) there exists a smooth vector-function $$F:O_x \to \mathbb{R}^{n-k}, \text{  } rank \frac{dF}{dx}|_q=n-k $$ such that $O_x \cap M = F^{-1}(0)$  (2) there exists a smooth vector-function $$f:V_0 \to \mathbb{R}^{n}$$ from a neighborhood of the origin $0 \in V_0 \subset \mathbb{R}^k$  with $$f(0)= x \text{   and   } rank \frac{df}{dx}|_0=k $$ such that $f: V_0 \to O_x \cap M$ is homeomorphism.  (3) there exists a smooth vector-function $$\Phi:O_x \to O_0 \subset \mathbb{R}^{n},$$ onto a neighborhood of the origin  $0 \in O_0 \subset \mathbb{R}^n$  with $$\text{  } rank \frac{d \Phi}{dx}|_x=n $$ such that $ \Phi(O_x \cap M)= \mathbb{R}^k \cap O_0$   I am trying to show the equivalence of these definitions and my first question is why is each definition imposing itself on the rank?


superclass object or subclass object? why?

I'm a Java beginner and I can't understand when I should create an instance of the superclass or subclass. I'm studying some tutorials online and I found a few times something like the following code:  package test;  class ABC{    public void myMethod(){     System.out.println("Overridden Method");    } } public class test extends ABC{     @Override    public void myMethod(){     System.out.println("Overriding Method");    }     public static void main(String args[]){     ABC obj = new test();     obj.myMethod();    } }   Why I should use ABC obj = new test(); instead of test = new test();? If I need a new ABC object wouldn't it make sense to just use ABC obj = new ABC();?  Thank you, sorry for the noobie question.


How do I call emergency services for someone in Ireland when I am in the US?

I know this question sounds ridiculous but it's important and I need to know the answer. If I knew that somebody in Ireland was in trouble and needed help (say for example: an ambulance) but there was no one else around them that could help them, how would I go about calling emergency services for them?   For example: I am on the phone to a friend in Ireland every day and I worry about how would I be able to help them if something came on suddenly (like they starting having a fit or something) and they weren't able to hang up our call and dial emergency services themselves.  I've done my research and already know that 999 and 112 are the main numbers for emergency services in Ireland, but would my call even go through to them? I'm in the US and don't have international calling, so my calls won't even go through to any other numbers outside of the US (though I can receive them).   Would I have to dial an area code before dialling 999 or 112? If you dial 999 or 112 in the United States, will you be connected to something else entirely? (Like a 411 type of deal?) or what if I just dialled 911 and explained the situation, would THEY get in contact with emergency services in Ireland?


saving odd numbers between two number in an array

Trying to save odd numbers between 2 numbers in an array  public class OddNumber {      static int[] oddNumbers(int l, int r) {         if (r <= l)             return null;         int size = ((r - l) / 2) + 1;         int arr[] = new int[size];         int p = 0;         for (int i = l; i <= r; i++) {              if (i % 2 != 0) {                 arr[p] = i;                 p++;             }         }         return arr;     }      public static void main(String[] args) {         System.out.println("Odd numbers between 2 & 9 are: " + oddNumbers(2, 9));     } }   It is always giving same junk value "Odd numbers between 2 & 9 are: [I@15db9742". I dont know what is the problem


What is this '°͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌' strange character?

I saw this °͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌͌ strange character online. I also noted that:   It needs 26 backspaces to delete but behaves like one character when selecting.   It is drawn vertically covering many rows above.  What is this character and why is it behaving like this ?


Are mods allowed to use secondary account(s) to cast non-decisive votes?

(Motivated by , now falsely dupe-closed question.) Mods can not cast non-decisive votes. . Sometimes they would like to talk with users so that the diamond does not alter their communication context. Sometimes they might like to feel the site as an ordinary mortal do. Shog (CM at the time) says :  If the second account allows you to do something on the site that your normal account would be prevented from doing, it is abuse.  On this definition, doing these as a mod, likely qualifies as an abuse: because the normal account of the mod is prevented to act as an ordinary user account. However, it is very likely, that this definition is about the increase of the privileges of the normal users, and not when mods want to decrease their privileges on some reason. Mods I've talked about it* categorically denied that they would use any socks, although he did not make clear that they would be allowed it, if they would want to. So what is the case? Are they allowed to use secondary accounts or not? *These are in long-deleted comment chats, I have no way to find/cite them.


Evolution threads extra lines before signature

I am using html emails with outlook style signature and with every reply in a thread, the signatures for each email gets a few additional lines above it... any ideas? (the issue is roughly like this)  # initial email Hello world,  -- # <- signature starts here from a. # next reply Hello back,  -- from b. ... Hello world    -- # <- additional lines above signature. from a.   etc.


Can you use a colon to introduce just a single item instead of a list?

Colons are usually used to introduce a list of some kind after an independent clause; however, would it work for a single item? For example, can you write     For 3 years, I ate hamburgers: my friend's favorite food.   If you do not use a colon here, what should be used?


Previously working version of Ubuntu now boots to black screen

I forgot to close my laptop or lock the screen before I went to work the other day, and when I came home my laptop was stuck on a black screen. I should also mention I have a cat who loves to walk and sit on my keyboard and I feel like she was probably the cause of this(I left bash open). I can get to grub when I restart, but if I try to boot with Ubuntu I just get the black screen again. I can't access the login page. I also have Windows 8.1 installed and I can boot that with no problem.  Any help would be greatly appreciated :)  Edit: I think it may be an issue with my drivers for my graphics card. I have an AMD Radeon HD 8510G. I haven't been able to bypass the black screen to update my drivers though. There was another post about this but the instructions weren't working for me. I tried changing quiet splash to nomodeset and radeon.modeset=0 but I still get the black screen when I boot.


A script for making another script deal with all files in sequence?

I have found a nicely working script to convert pdf files into txt format, with ocr.   But it converts only one pdf file each time. I need to mass-convert them.   I have no knowledge of script writing. The script is at below.   How can I mass convert them?  #!/bin/bash  ## script to: ##   *  split a PDF up by pages ##   *  convert them to an image format ##   *  read the text from each page ##   *  concatenate the pages   ## pass name of PDF file to script INFILE=$1  ## split PDF file into pages, resulting files will be ## numbered: pg_0001.pdf  pg_0002.pdf  pg_0003.pdf pdftk $INFILE burst  for i in pg*.pdf ; do      ## convert it to a PNG image file     convert -density 200 -quality 100 $i ${i%.pdf}.png      ## read text from each page     tesseract ${i%.pdf}.png ${i%.pdf}.txt  done  ## concatenate the pages into a single text file cat pg*.txt > ${INFILE%.pdf}.txt  exit   Note: I have read the similar questions but couldn't figure it out.


I'm working on a  and would like to know how to structure my map data. I suppose this question could also be extended to any sort of top down 2d game. Anyways! My game will contain object types like terrain, doors, switches, monsters, and items. How should the objects be stored within a map?   Some ideas I've gathered online:   The map is a 2d array. Each cell in the array can store multiple references to objects occupying it. The map contains several layers of 2d arrays, and each layer stores references to objects of a specific type. Like 1. but only store static terrain information in the 2d array. The rest of the objects are dynamic and stored in lists for each type.