I don't know how I triggered this user, but for me it was really a kinda funny thing to happen. In this situation, what should you do?  This user answered a question but with just a link; I suggested that putting some examples would be great for his answer, but suddenly this guy started to rage, as you can see in the image below. Now I won't blame him - maybe he just had a hard time or anything else - but officially, these things should not be happening, right? What can we do?

I recently responded to  that appeared to post an extension to their answer in a comment, (what I thought was) kindly letting them know that comments may not last forever.  However, it ended up in this kerfuffle:    After posting the reply comment, I felt that it wasn't the best course of action to have taken, but to take it back also seemed inappropriate.  What should I have done, and does my original comment seem appropriate in the given situation?


My system is infected by a malware that keeps modifying a particular configuration file. Is there a way/tool to find out which program is making change to a particular file?  I am simply looking for a tool that can help monitor changes to a particular file. Not really a full fledged forensics response.

This is a  about Server Security - Responding to Breach Events (Hacking)   See Also:                  Canonical Version I suspect that one or more of my servers is compromised by a hacker, virus, or other mechanism:   What are my first steps? When I arrive on site should I disconnect the server, preserve "evidence", are there other initial considerations? How do I go about getting services back online? How do I prevent the same thing from happening immediately again? Are there best practices or methodologies for learning from this incident? If I wanted to put a Incident Response Plan together, where would I start? Should this be part of my Disaster Recovery or Business Continuity Planning?   Original Version       2011.01.02 - I'm on my way into work at 9.30 p.m. on a Sunday because our server has been compromised somehow and was resulting in a    attack on our provider. The servers access to the Internet   has been shut down which means over 5-600 of our clients sites are now   down. Now this could be an FTP hack, or some weakness in code   somewhere. I'm not sure till I get there.      How can I track this down quickly? We're in for a whole lot of   litigation if I don't get the server back up ASAP. Any help is   appreciated. We are running Open SUSE 11.0.            2011.01.03 - Thanks to everyone for your help. Luckily I WASN'T the only person responsible for this server, just the nearest. We managed   to resolve this problem, although it may not apply to many others in a   different situation. I'll detail what we did.      We unplugged the server from the net. It was performing (attempting to   perform) a Denial Of Service attack on another server in Indonesia,   and the guilty party was also based there.      We firstly tried to identify where on the server this was coming from,   considering we have over 500 sites on the server, we expected to be   moonlighting for some time. However, with SSH access still, we ran a   command to find all files edited or created in the time the attacks   started. Luckily, the offending file was created over the winter   holidays which meant that not many other files were created on the   server at that time.      We were then able to identify the offending file which was inside the   uploaded images folder within a  website.      After a short cigarette break we concluded that, due to the files   location, it must have been uploaded via a file upload facility that   was inadequetly secured. After some googling, we found that there was   a security vulnerability that allowed files to be uploaded, within the   ZenCart admin panel, for a picture for a record company. (The section   that it never really even used), posting this form just uploaded any   file, it did not check the extension of the file, and didn't even   check to see if the user was logged in.      This meant that any files could be uploaded, including a PHP file for   the attack. We secured the vulnerability with ZenCart on the infected   site, and removed the offending files.      The job was done, and I was home for 2 a.m.            The Moral   - Always apply security patches for ZenCart, or any other CMS system for that matter. As when security updates are released, the whole   world is made aware of the vulnerability.   - Always do backups, and backup your backups.   - Employ or arrange for someone that will be there in times like these. To prevent anyone from relying on a panicy post on Server   Fault.


I'd like to understand common and practical username creation conventions which could be used in companies as unique names of user accounts. Let's say a small company with perspective of growth wants to consolidate its home-grown IT and want to deploy their first enterprise-wide solution. What username would be assigned e.g. to Martin Scorsese, Leonardo DiCaprio, Joey McFarland and Emma Tillinger Koskoff? Please illustrate on these names as they cover some less typical cases. Please do not simply suggest a naming scheme, but add an explanation of its rules. Mind the conflict resolution when person with duplicate name joins the company or when different names in some cases lead to same username.  I already have experience with naming scheme which would lead to: mscorsese, ldicaprio, jmcfarland and etkoskoff. It does not give nice result when sorted and usernames are not very readable, but they are kept short and avoid most common duplicates (John and Adrian Smith won't collide).  I'm especially interested in username schemes suitable for companies up to 1000 employees, but experience with usernames in large corporations (100.000+ employees) is welcome, too.

I'm interested in finding out what people's experiences with standard usernames is. I've always been in places that used {firstInitial}{lastname} (sometimes with a length-limit). Now I've users that want {firstname}.{lastname} - and now it comes up that the period may cause problems.  Specifically:   What is the best username length limit to use to maintain compatibility across all uses? What characters should be avoided?   UPDATE: The reason I didn't mention specifics is that I wanted to be general enough to handle anything that might come up in the future. However, that may be too general of a requirement (anything can happen, right?).  This is our environment: Ubuntu Server Lucid Lynx 10.04 LTS, Red Hat Enterprise Linux 5.6 and up, Windows Server 2003 and Windows 2000 Server (with Active Directory in Windows 2000 Native Mode), Zimbra 7.x for mail, and OpenLDAP in the near future.  UPDATE: I should mention (for completeness) that I saw  (though it didn't answer my asked question) and also this , both of which were very informative.


Can Junit be multi threaded say multiple threads trying to run different Junit tests to complete faster assuming each TestCase is mutually independent .. I could not find any configuration as such .

I'm using JUnit 4.4 and Maven and I have a large number of long-running integration tests.  When it comes to parallelizing test suites there are a few solutions that allow me to run each test method in a single test-class in parallel. But all of these require that I change the tests in one way or another.  I really think it would be a much cleaner solution to run X different test classes in X threads in parallel. I have hundreds of tests so I don't really care about threading individual test-classes.  Is there any way to do this?


I am writing code for Elliptic Curve Cryptography. I have a class class EllipticCurvePoint.  class EllipticCurvePoint{     FieldElement x, y; };   I need to support point-at-infinity (which should behave as if it is an object of type EllipticCurvePoint). Only thing I can think of is to reserve (-1, -1) for this but x and y can assume values only from {0, 1, ..., p-1} (p being the Field they belong to). If I want to represent it this way, I would need to add support for -1 in the classes FieldElement and Field too.   I have also overloaded the + and the * operators which work perfectly fine for other points. But I cannot think of a way to represent point-at-infinity which can work homogeneously with the rest of the code and I wouldn't have to change the parent classes(Field and FieldElement).  Is there any elegant way to achieve this? Thanks a lot for your time!

I'm testing an implementation of Bitcoin, which uses the curve Secp256k1 for ECDSA, and I want to see how it handles the point at infinity ($0$) if present in a signature. For example, r could be the x coordinate of the encoding of the point at infinity.   How is the $0$ encoded? Can it be encoded?  I found that bouncycastle prefixes the encoding of 0 with 0x00, and has some other defined prefixes (ECCurve.decodePoint()) but I don't known how this information applies (or even if it does apply to) to the encoding of $(r,s)$. This info seems to be in the X9.62 standard.


public class PickListController {   global static list<SelectOption> getPicklistValues ('Employee__c' , 'Priority__c') {     list<SelectOption> options = new list<SelectOption>();      // Get the object type of the SObject.     Schema.sObjectType objType = obj.getSObjectType();       // Describe the SObject using its object type.      Schema.DescribeSObjectResult objDescribe = objType.getDescribe();          // Get a map of fields for the SObject      map<String, Schema.SObjectField> fieldMap = objDescribe.fields.getMap();        // Get the list of picklist values for this field.      list<Schema.PicklistEntry> values =      fieldMap.get(fld).getDescribe().getPickListValues();       // Add these values to the selectoption list.      for (Schema.PicklistEntry a : values)      {          options.add(new SelectOption(a.getLabel(), a.getValue()));       }      return options;    }  }

I have a Student object and have a pick list field  "Student Status" in this object. Status can be Full-Time OR Part Time. Now my requirement is i want this student status list, Part-Time or Full-Time in apex controller. how can i do this?  If i get a student record it will only give me that particular student status Full-Time or Part-Time. But i need all options that are available in student status field.  Please help me


So, this equation we get when we find  that makes new hamiltonian=0. There are 4 main transformations: F1(q,Q,t), F2(q,P,t), F3(p,Q,t), F4(p,P,t). On practice and in every book I've seen, we use F2 and F1 to solve Hamilton Jacobi equation, but can we use F3 and F4?

The derivation of the Hamilton-Jacobi equation using canonical transformations is typically done involving a type-2 generating function.  Is it possible to use a another type of generating function, namely type 1, 3 or 4?


whenever I run :   sudo apt-get update   I get this message below:   W: The repository 'cdrom://Ubuntu 16.04 LTS _Xenial Xerus_ - Release amd64 (20160420.1) xenial Release' does not have a Release file.  N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.  N: See apt-secure(8) manpage for repository creation and user configuration details.  W: The repository 'ppa.launchpad.net/kirillshkrogalev/ffmpeg-next/ubuntu xenial Release' does not have a Release file.  N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.  N: See apt-secure(8) manpage for repository creation and user configuration details.  E: Failed to fetch cdrom://Ubuntu 16.04 LTS _Xenial Xerus_ - Release amd64 (20160420.1)/dists/xenial/main/binary-amd64/Packages  Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs  E: Failed to fetch cdrom://Ubuntu 16.04 LTS _Xenial Xerus_ - Release amd64 (20160420.1)/dists/xenial/main/binary-i386/Packages  Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs  E: Failed to fetch ppa.launchpad.net/kirillshkrogalev/ffmpeg-next/ubuntu/dists/xenial/main/binary-amd64/Packages  404  Not Found  E: Failed to fetch ppa.launchpad.net/kirillshkrogalev/ffmpeg-next/ubuntu/dists/xenial/main/binary-i386/Packages  404  Not Found  E: Some index files failed to download. They have been ignored, or old ones used instead.   I used    sudo nano /etc/apt/sources.list   and comment or remove lines that include cdrom. eg:  deb cdrom:[Ubuntu-Server 16.04 LTS Xenial Xerus - Release amd64 (20160420.3)]/ xenial main restricted>   I was be able to remove it. when I ran sudo apt-get update , got the error message below.  W: The repository 'http://ppa.launchpad.net/ubuntu-on-rails/ppa/ubuntu xenial Release' does not have a Release file.  N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.  N: See apt-secure(8) manpage for repository creation and user configuration details.  E: Failed to fetch http://ppa.launchpad.net/ubuntu-on-rails/ppa/ubuntu/dists/xenial/main/binary-i386/Packages  404  Not Found  E: Some index files failed to download. They have been ignored, or old ones used instead.   could anyone shed some light on this please ? Thanks a million in advance.

PPA seems to be constantly offline. Whenever I use sudo apt-get update, this error is shown:  W: Failed to fetch http://ppa.launchpad.net/ 404  Not Found   How do I fix these errors?


--Editing this as my question was marked as a duplicate. I'm having an issue implementing STUFF and the "trick" FOR XML PATH when my query contains a join.  I have a single column that I have been trying to convert to a single column and single row. The data structure returned from the query below is:  col1 1  2 3   I'd like it to be comma delimited like so:     col1     1,2,3  The query I have is as follows:  select    u_id from    tabl1 tb   inner join CTEE f on f.aid = tb.a_id group by    u_id   I tried to incorporate STUFF and a FOR XML PATH in this query but keep failing to do so. Can anyone point me in the right direction. I've done this for multiple columns when concatenating rows into a comma delimited column, but for some reason this is driving me crazy.

I'm trying to migrate a MySQL-based app over to Microsoft SQL Server 2005 (not by choice, but that's life).  In the original app, we used almost entirely ANSI-SQL compliant statements, with one significant exception -- we used MySQL's group_concat function fairly frequently.  group_concat, by the way, does this: given a table of, say, employee names and projects...  SELECT empName, projID FROM project_members;   returns:  ANDY   |  A100 ANDY   |  B391 ANDY   |  X010 TOM    |  A100 TOM    |  A510   ... and here's what you get with group_concat:  SELECT      empName, group_concat(projID SEPARATOR ' / ')  FROM      project_members  GROUP BY      empName;   returns:  ANDY   |  A100 / B391 / X010 TOM    |  A100 / A510   So what I'd like to know is: Is it possible to write, say, a user-defined function in SQL Server which emulates the functionality of group_concat?   I have almost no experience using UDFs, stored procedures, or anything like that, just straight-up SQL, so please err on the side of too much explanation :)


Following program:  #include <stdio.h> #include <stdlib.h>  int main() {     int *array;     array = malloc(sizeof(int)*100);      for(int i=0; i<sizeof(array); i++) {     printf("%d\n",i);     }     free(array); }   It display 0-3. But I expected 0-399. I thought the size will be calculated through 4*100.

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


When I try the following in racket:   (* 1.1 1.1)   why does it return   1.2100000000000002   instead of  1.21   while   (* 1.2 1.2) ; is 1.44, as expected   Edit  and the following returns false:  (= (* 1.1 1.1) 1.21); #f

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


I use ssl to secure RMI and JMS communications between clients and server. I add keyStore and trustStore files to resource folder of my project. When the project run through Netbeans, these file are loaded without any problem, using below codes:  System.setProperty("javax.net.ssl.keyStore", "src/main/resources/certificates/keyStore.ks"); System.setProperty("javax.net.ssl.keyStorePassword", "pass"); System.setProperty("javax.net.ssl.trustStore", "src/main/resources/certificates/trustStore.ts"); System.setProperty("javax.net.ssl.trustStorePassword", "pass");    But, when I run this project through its jar file, these files cannot be loaded.   Is there any alternate way to config SSL instead of using System.setProperty() and specifying the paths to keyStore and trustStore files?   Also, it works in both modes (run through Netbeans and Jar file).

I'm trying to do something like   URL clientks = com.messaging.SubscriptionManager.class.getResource( "client.ks" ); String path = clientks.toURI().getPath(); System.setProperty( "javax.net.ssl.keyStore", path);   Where client.ks is a file stored in com/messaging in the jar file that I'm running.  The thing that reads the javax.net.ssl.keyStore is expecting a path to the client.ks file which is in the jar. I'd rather not extract the file and put in on the client's machine if possible. So is it possible to reference a file in a jar?  This doesn't work as getPath() returns null. Is there another way to do this?


Say you're doing something computational where each data point is a tile in a (not necessarily Euclidean) 2-dimensional tiling, for instance, a Life-like cellular automata. You might want a data structure where tiles that are near in distance are also near each other in memory. You might choose your tiling based on what's easy to represent this way.  For a tiling of the Euclidean plane, you probably have square tiles backed by a 2d array with array point a[i][j] = tile $a_{ij}$; you might have hex tiles instead, which can also be backed by a 2d array as explained in .  For a tiling of the sphere, it's pretty common to start with a sub-triangulation of the icosahedron and subdivide it into 5 2d arrays plus 2 points for the north pole, as explained in . It looks like a geodesic dome.  Is there a 2d hyperbolic tiling that admits a representation in a nice data structure? The only software I've ever seen that uses hyperbolic tiling in this way is the game HyperRogue (a roguelike on the hyperbolic plane). It just has an object for each tile, and each tile keeps a record of its neighbors. It works but it's not pretty.

Rephrasing     (one year later)    (original question is below)   Apparently the original question wasn't clear, or nobody knows an answer (or both).  So I will try to rephrase it.   Look at your favorite .  This question asks for a labeling system for the points.  Of course we could draw the grid on the Poincare disk, and use real numbers (the (x,y) coordinates of each point), but in practice that would raise all sorts of precision issues that could surely be avoided if one had a proper symbolic coordinate system.  You shouldn't need real numbers if you're staying on grid points!  Just like (2,3)+(0,1) is trivial to do by hand (or in your head) for the square grid, we'd like some form of symbolic coordinates (i.e. consisting of finite sequences of symbols) for a hyperbolic grid, in which simple operations on small grid vectors are similarly easy.  If you take some sequence of left and right turns in a hyperbolic grid city, what should you keep track of in your head so you can take the optimal route back to your starting point?  In a Euclidean square grid, it is {(int)X, (int)Y, (enum)direction you are facing}, and we all know how to use this.  Is there any hyperbolic grid where this question has a nice answer?    Original Question  If we consider the Euclidean plane, then a square grid works well with using two integers (the coordinates) as a representation for vectors that lie on the grid.  Does anybody know of a similarly nice representation for working in the hyperbolic plane?  Desirable features of any such system:  $-$ It should be easy to add two vectors.  $-$ It should be easy to see if two vectors are the same.  $-$ It should be easy to see if two vectors are close.  $-$ It should be easy to rotate a vector by an angle that is a symmetry of the grid.  $-$ Every point in the plane should be near some vector. (The grid shouldn't have large empty regions.)   Note that "addition" using continuous coordinates would most naturally be defined in terms of parallel transport, and it is neither commutative nor associative.  On a grid, however, the issue of orientation needs to be addressed differently, since parallel transport along arbitrary grid vectors will introduce rotations that are not a symmetry of the grid, so to remain on the grid, addition will need to be defined using something other than parallel transport.  Since hyperbolic grids have an exponential number of points (as a function of distance from the origin), our symbolic coordinates will need to have a length proportional to the length of the vector.  Don Hatch has a web page which gives some .  ("Easy" means an efficient algorithm that is doable by hand, like how the algorithms for addition and subtraction using the standard digit-sequence representation of integers can be used for the Euclidean square grid. Using hyperbolic functions of real numbers, always keeping track of enough digits to identify the nearest grid point, does not count as easy!)    Addendum: Many readers seem to be disturbed by a little voice saying "But vectors don't make sense in the hyperbolic plane!": What that voice is really saying is that the hyperbolic plane doesn't give you all the nice properties you are used to in Euclidean space or in vector spaces.  So if you define vectors as objects having specific properties you are used to (such as having a direction that is unaffected by parallel transport), then that definition may not correspond to anything in the hyperbolic world.  You could use the term isometry, but that is typically a fixed mapping from the space to itself, and in the hyperbolic plane the isometry corresponding to a vector would depend on the starting point. (However, isometries will be central to any solution, I assume.) And a geodesic is a fixed path within the space, no different from a hyperbolic line or segment.  The paper  offers one solution.  offer another.  I deliberately leave them undefined in this question, as I am looking for any workable system.


In Drupal 7, what methods are there to add additional textfields to the user registration page at /user/register? I mainly want to also get their first + last name during registration. There doesnt seem to be a way via the interface to add these extra fields as required for sign up.   What is the quickest way of adding these extra text fields on sign up?

In Drupal 7, is there a way to add more fields to the registration process? I was thinking along the lines of birthday, fullname, gender, twitter, etc. Also how do I access this data once it's in, so I can output it to my template files?


Is it a good idea for someone in the middle class to invest in physical gold as a safe guard against economic crisis?  If not, why not? If yes, still why? I'm also curious what percentage of savings should be kept in physical gold. What if you're from the lower middle class, or upper middle class, does that affect anything?

I'm becoming more interested in buying gold / silver coins as a hedge against inflation and especially hyperinflation. I know very little about this, and there are thousands of sites on the internet about this. I'm sure many of them are a little less than honest.  For those of you who are experienced with this, could you point me to reputable sites that can explain how to go about doing this and perhaps reputable sites where gold and silver coins can be purchased?  Thanks very much.


I'm trying to make a multi column layout. Seen as CSS3 adoption of column layouts is still thin on the ground, I was thinking maybe I could grab the first half of all my posts (and then the second), and add them in their own UL elements.  I'm not sure how / if this is possible with a Wp_Query?  I want to end up with my posts in alphabetical order, but split into two lists (using two queries, I guess), thus:

a
 . . .
m

n
 . . .
z

   I could then style each list with CSS and get a layout kind of like a multi column layout in CSS3.  Does anyone have any ideas about how to structure my queries here?  edit to explain how this isn't a duplicate  It's about forming a two column layout sure, but the question is very different: 'how to get half of all posts', not how to solve a very specific layout use case as is the linked 'duplicate'. (which I didn't find on account of it not being the same question).  Further, I was looking for posts sorted alphabetically, vertically descending, not A|B, C|D as in the example.

I am trying to output a list of stockists in two columns from left to right, sorted alphabetically:  A | B  C | D  E | F  G | H  Currently, the code below is sorting half the posts alphabeticly and then starting half way through with the rest alphabeticly:  A | C  E | G  B | D  F | H  Any idea on where I am going wrong?  <?php  query_posts(  array( 'order' => 'ASC' , 'orderby' => 'title' , 'posts_per_page' => -1 , 'post_type' => 'stockist_directory', 'regions' => 'metropolitan' ) ); if (have_posts()) : while(have_posts()) : $i++; if(($i % 2) == 0) : $wp_query->next_post(); else : the_post(); ?>

<?php the_title(); ?>
   <?php the_field('shop_address'); ?>
   <?php the_field('suburb'); ?>, <?php the_field('postcode'); ?>
   Phone: <?php the_field('phone_number'); ?>
   <a href="<?php the_field('website_address'); ?>">Website
  <?php endif; endwhile; else: ?> <?php endif; ?>  <?php $i = 0; rewind_posts(); ?>  <?php if (have_posts()) : while(have_posts()) : $i++; if(($i % 2) !== 0) : $wp_query->next_post(); else : the_post(); ?>

<?php the_title(); ?>
   <?php the_field('shop_address'); ?>
   <?php the_field('suburb'); ?>, <?php the_field('postcode'); ?>
   Phone: <?php the_field('phone_number'); ?>
   <a href="<?php the_field('website_address'); ?>">Website
 <?php endif; endwhile; else: ?>  <?php endif; ?>


I want to if this sentence is correct.      Collecting metals from electronic waste and reusing them to make other products is called the “urban mining industry.   In the sentence the two gerunds are used as a subject and the verb is 'is', the singular form. Is is correct? Is it wrong if I use 'are' as a verb?

I'm trying to find out whether I should use a singular or plural verb when there are multiple gerunds as the subject of the sentence. For example:  Running the correct course and keeping a steady pace are/is necessary in order to win.  With either one of these by itself, "is" would be correct:  Running the correct course is necessary in order to win. Keeping a steady pace is necessary in  order to win.  With both gerunds combined, I can't seem to figure out whether the verb should stay singular since each phrase is singular, or if it should become plural since there are two connected by "and". If we just treat the gerunds as regular nouns, then obviously it would become "are", but I'm not sure if gerunds have the exact same rules as regular nouns. I know that if the sentence was:  Running the correct course and keeping a steady pace are both necessary.  That "are" would be correct, but without the "both" it sounds incorrect to me. Does anyone know the official rule here?


Are there any canon sources of a person using the Force to deactivate an opponent's lightsaber during combat?  There's  because somebody could just use the Force to activate it. There's even a comment there about somebody using the Force to deactivate a weapon,      If a lightsaber was only activated by the Force, how would that stop a Sith from deactivating a Jedi's lightsaber?   but as far as I can tell there's no question of deactivating one during combat as suggested by the comment above.  There's also . (Different from activating one using the Force.)  And there's .  But no question that I found about merely deactivating one to disarm an opponent. Seems like a fairly simple way to win a lightsaber duel. Has anyone done this during combat?

Lightsabers turn OFF when its wielder drops it or he/she dies. It means there's some kind of pressure button on lightsabers which needs to be always pressed to keep is ON.  In case of lightsaber throw, one uses the Force for that. It means, lightsabers can be turned ON using the Force.  Why doesn't someone try to turn ON enemy's lightsaber to do some lethal damage to someone nearby? Or, has this happened in any canon?


BB-8 seems to have a sense of humour and have a cheeky/nasty side to him but is there a full list of what he is meant to be saying (not just fanboy hopeful assumptions)?  As there is dialog for Chewie and other characters who speak other languages but does any exist for this droid in particular?

When R2-D2 and BB-8 converse in The Force Awakens for example, is there any written record of what the two characters were saying to each other?  I mean actual dialog, if it exists, and not something like ”BB-8 beeps excitedly”.


When I hover over the text, the text moves. The reason that the text is moving is that I remove the bold effect on hover. How to stop the text to move on hover?  #menu li a{     color:#595959;     font-size:14px;     font-weight:bold;     position: relative;      overflow:hidden;     padding:2px 5px; }  #menu li a:hover{     color:#FFFFFF;       font-weight:normal;     background-color:#e11d3b;     -webkit-border-radius: 5px;     -moz-border-radius: 5px;     border-radius: 5px;      text-decoration:none;    }

I created a horizontal menu using a HTML lists and CSS. Everything works as it should except when you hover over the links. You see, I created a bold hover state for the links, and now the menu links shift because of the bold size difference.  I encounter the same problem as . However, the post does not have proper solution. I've searched everywhere for a solution and can't find one. Surely I can't be the only one trying to do this.  Does anyone have any ideas?  P.S: I don't know the width of the text in menu items so I cannot just set the width of the li items.    .nav { margin: 0; padding: 0; } .nav li {      list-style: none;      display: inline;      border-left: #ffffff 1px solid;  } .nav li a:link, .nav li a:visited {      text-decoration: none;      color: #000;      margin-left: 8px;      margin-right: 5px;  } .nav li a:hover{      text-decoration: none;      font-weight: bold;  } .nav li.first { border: none; }

item 0

item 1

item 2

item 3

item 4


Currently using the standard math font and was hoping to modify the standard \omega symbol. How do I go about configuring this so that I can get the \omega symbol from a different font package, say {fouriernc}, or something. Appreciate the help.

Is there a general way to change the font of a particular symbol without switching packages?  For example, suppose I'm using Computer Modern for my entire document, but I want the "subset" operator to look as it does in mathabx.  How can I redefine it to appear in this way?


Why these two code snippets have different behaviors  char p[] = "hello"; p[0] = 'W'; //works fine   While this gives a segmentation fault  char *ptr = "hello";  ptr[0] = 'W'; // undefined behavior   What is the difference between both codes,why i am unable to modify the string using pointer?

The following code receives seg fault on line 2:  char *str = "string"; str[0] = 'z';  // could be also written as *str = 'z' printf("%s\n", str);   While this works perfectly well:  char str[] = "string"; str[0] = 'z'; printf("%s\n", str);   Tested with MSVC and GCC.


I am new in Machine learning techniques and in fake news detection by using these algorithms (SVM, nn, logistic regression,..). I would like to understand how an algorithm can learn from a training set which include news and fake news, what it will be necessary to have (target), what type of information can be relevant for a good analysis and learning ... I read many papers and most of them do not mention the type of news used, the criteria for building the classifiers, but they only show the results of the prediction when a new news is generated. This could be perfectly fine, but it could be also easily to say: I got this amazing results!, without understanding how these results were got. I would appreciate if you could show me an example of how an algorithm can learn from text (not necessarily news, but also tweets, or something else would be fine). Following discussion with Erwan: one of his previous answer partially has answered my question. However I would like to understand the following. One needs to have a corpus, then label news/tweets in fake/not fake, then run the model. But how the algorithm works on texts and takes relevant words or features for detecting fake news? So my question is: If I have a corpus on Trump, would the algorithm be able to detect fake news on Vitamin C, without any words (verb, adj, noun,..) in common between the two dataset, except stopwords?

I would like to work on a project for Fake News Detection especially for Indians news which are in different languages and different formats.   Fake news as image with no or very less text Fake news on a blog site Fake news as Tweets Fake news in Hindi Fake news in the watsapp group and shared across.   Need your help on the approach. One approach I can think of is using OCR we can read the content of the post, then search those content in the google. If the news is not present in any of the famous print media then we can tag it as fake. However there can be many challenges in this. What if the print media itself gives any fake news shared by someone.  How to handle the scenario where there is no text in the image but the information shown as image is fake.  How to handle posts written in Hindi. ?  And even if we detect fake news, is there any way to make the person accountable for sharing it. ? I know it is little difficult problem to solve. But is there any work currently done by any company on this. ?  Any starting point for me to get into this domain ?


TLDR     While editing questions, is there any problem if I change the spelling of words in American English to British English unknowingly (as suggested by my computer)?   The long version  I am an Indian and my system language is set to Indian English.  There are lots of differences in spelling between American English and Indian English (Indians use British English).  Well, some examples are here from           centre <=> center   fibre <=> fiber   litre <=> liter   theatre <=> theater   colour <=> color   flavour <=> flavor   humour <=> humor   labour <=> labor   neighbour <=> neighbor   analyse <=> analyze   breathalyse <=> breathalyze   paralyse <=> paralyze        While editing questions, The American English words are highlighted by a red color indicating there is a typo.    But actually it is not a typo and for some words, I know it is American English. But some words, I don't know whether it is a typo or an American English word.  If the highlight is inside a code block, I leave it as it is.  But in other places, sometimes I correct it by doing    Is there a problem in doing so? If I doubt a word whether it is a typo or is a local version of English, what should I do? Correct it or leave as it is? What is the official statement of SE about this?

I just saw someone edit the title of  question to  the spelling from favourite (The British spelling) to favorite (The US-English spelling).  Does SOFU have an accepted standard on language and spelling? Which is it?


I have the next problem:  I am making a simple cast:   TargetBot2Params params = (TargetBot2Params)bot.getParams();   But I get the next error:  Inconvertible types   Requiered: TargetBot2Params   Found: UT2004BotParameters   And I dont know why occurs this, because I think that it doesnt do the cast.  Anyone knows why occurs this?  Thanks for your time.

Here's what I've been trying to do, in a nutshell:  class example <T extends Number> {     private int function(T number)     {         int x = (int) number;         ...     }     ... }   Basically, I'm trying to make it so that T is a number so I can convert it to an int inside that function. The problem is that I'm getting an "incovertible types" error, so I must be doing something wrong.


I have recently purchased my new laptop ASUS Vivobbok S14. i7, 8gb, 512gb version which comes with windows 10 pre installed. I am willing to install ubuntu 18 on this machine. Is there a support for my machine?? I have been reading many posts and came to know that there are backlight keyboard and wifi issue after the installation. And the battery backup is also reduced as compared to windows. I am a programmer, I need to upgrade only if there is full support/drivers available for my machine.

I have a device on which I would like to install Ubuntu. How do I find out if Ubuntu will work on it?


EDIT: I am convinced that this is not a very helpfull idea.  When I first found Stack Overflow I was amazed at the speed at which people answered my questions. The quality was amazing as well and I solved a lot of issues with the help of this community.  Over time I started to feel the urge to give back. Nowadays I spend most of my idle time at work helping to answer PHP questions on SO.  What I keep running into is ungrateful people who do not bother reading answers, clicking links or even putting the tiniest bit of effort into providing the information needed to solve their issues.  Those users mostly have a name that starts with "user" and is followed by a long random number. Because they care so little, they didn't even bother to pick a nickname.  I co-run a free DIY Self-help Bike Workshop. Basically people come in, they can use the tools for free, we provide recycled parts that we get from donated old bikes and we help people to fix their bikes.  Sometimes, people come in and just demand that we fix their bike for free and they demand modern, quality parts and someone even suggest we just bring him the bike to his house once we finished fixing it.  My Point is: Maybe the registration process does not have to be that easy.  It might end up destroying a community that is already flooded with very low quality questions.

When a user signs up , their username is something along the lines of "user########"  Granted, in the welcome email it does say something along the lines of "Head over to your user account page to chose a display name!", however only a few people actually read that email.  I'm not saying we should restrict people from changing their display name again in the future - Everyone would still be able to do so. It's just that when you sign up you choose an initial display name that will be what your first display name is instead of "user########".


Look at this:        There are several problems:   | help | chat | log out | is on its own line and should be on the same line as Area 51 Right angle thing (∟) is out of place No space between site icon and site name anywhere No space between lines in the "Your Communities" list   Please fix.

The content in the site switcher, inbox and achievements of the Area 51 are misaligned. I can verify the issue in recent Google Chrome and Mozilla Firefox browsers with 100% zoom.


Could someone guide me through logic for this combinatorial proof   Let $c_n$ denote the number of triangulations of a regular $(n + 2)$-gon by non-intersecting diagonals.

Assume $C_n$ is the number of triangulations of a polygon with $n+2$ sides. Using a combinatorial proof, show that $(4n+2)C_n=(n+2)C_{n+1}$.  I don't even know where to start with this one. I understand the triangulation after doing some googling, but I don't know where to go from here to prove the above using just a combinatorial formula.


I am trying to dynamically expand a list to include duplicates. I managed to achieve this without VBA, but after condensing several columns containing intermediary functions I have tied myself in a knot of circular references. I'm not convinced I can get it working again, so I turn to SU for help.  I have a table as below:          APPLE  BANANA   CHERRY  DATES JOHN      x                x PAUL              x GEORGE    x       x RINGO     x       x        x      x   I need to create from this two columns containing the following:  JOHN         APPLE JOHN         CHERRY PAUL         BANANA GEORGE       APPLE GEORGE       BANANA RINGO        APPLE RINGO        BANANA RINGO        CHERRY RINGO        DATES   That is, each individual instance of Fruit is listed. I am able to create the second column, i.e. the list of fruits according to the Eater; I just can't get the first column.  From here the list will be expanded again. Let's say I have another table:  FRUIT    LINES APPLE      2 BANANA     3 CHERRY     1 DATES      2   The ultimate list I would like to end up with is:  JOHN         APPLE          1 JOHN         APPLE          2 JOHN         CHERRY         1 PAUL         BANANA         1 PAUL         BANANA         2 PAUL         BANANA         3 GEORGE       APPLE          1 GEORGE       APPLE          2 GEORGE       BANANA         1 GEORGE       BANANA         2 GEORGE       BANANA         3 RINGO        APPLE          1 RINGO        APPLE          2 RINGO        BANANA         1 RINGO        BANANA         2 RINGO        BANANA         3 RINGO        CHERRY         1 RINGO        DATES          1 RINGO        DATES          2   That is, each line is repeated according to the number in the "Fruit/Lines" table. I'm sure this second step is just a replication of the first step, rather than one complete set of functions.  Any help will be appreciated.  The duplicate question, , doesn't cover the dynamic element; steps 5 and 6 are "copy list and paste values" and "filter column and delete nulls" are not suitable for this application.

I have multiple items that are available in multiple distribution centers (i.e., a many-to-many relationship). There is currently one row per item, with one column for each distribution center. A cell in the row for item X and the column for distribution center Y is marked with the code for distribution center Y if item X is available there and blank otherwise. An item with multiple distribution centers will have multiple distribution center codes (in their respective columns). So the current sheet looks like:      |   A    |         B         |*|                      S-AJ                      | 1   |  ID #  |   Description     |…|              Distribution Centers              | 2   |   17   |   Ginkgo Biloba   |…|      |      |      |      |      |      |  SE  | 3   |   42   |   Ginseng         |…|      |  MP  |  MS  |      |  NW  |      |      |                      ︙   Columns C through R contain other attributes of the items, such as UPC code, cost, and price, which are not relevant to this question. My actual sheet has 18 distribution centers, spanning columns S through AJ; I reduced that to get the example to fit into Stack Exchange’s window.  I need to have a single distribution center column, with a single distribution code per row, and then duplicate the rows as needed for items that currently contain multiple codes. The result should look like:      |   A    |         B         |*|   S  | 1   |  ID #  |   Description     |…|  DC  | 2   |   17   |   Ginkgo Biloba   |…|  SE  | 3   |   42   |   Ginseng         |…|  MP  | 4   |   42   |   Ginseng         |…|  MS  | 5   |   42   |   Ginseng         |…|  NW  |                      ︙   where cells A3:R3, A4:R4, and A5:R5, contain the same information.  The only way I can think of doing this, which would be time consuming, would be to copy the item number into multiple rows; and in the column that has the distribution code I would change code for the item that is available in each distribution center. I will be doing this for 900 items. Is there an easier way to do this?


I have directory named "public" in every directory inside Documents. I want to copy file named File.txt in every directory "public".  cp -r File.txt Documents/*/public/   doesn't seam to work. What should I do?

Is it possible to copy a single file to multiple directories using the cp command ?  I tried the following , which did not work:    cp file1 /foo/ /bar/ cp file1 {/foo/,/bar}   I know it's possible using a for loop, or find. But is it possible using the gnu cp command?


For example, ‘speaker’ sounds like ‘speager’ and ‘Stop it’ sounds like ‘stob it’.

I am a Chinese student beginning to learn English. I am curious to know why the word student is pronounced with the sound of d instead of t. Likewise, why is the sound of b used instead of p when people say suspend?


II would like to store two values (an email and a password) in a MySQL db using PHP. The input is passed to the PHP page via Ajax in jQuery (through an onclick event on a website). Now I want to protect this PHP query against SQL injection - I am talking about a standard website so I don't want to overdo it but I think some standard protection can't be bad. Below is what I had before just to ensure that the general procedure is working which it is. I then tried to increase security by using password encryption and statements but I am not sure if I did this the right way + I don't know if and how this needs to be applied to the Select part as well (where I am checking if the email already exists). I've seen plenty of pages on this topic but as a beginner that's exactly my problem here. Can someone tell with this as an example what should be changed or added here and maybe provide some short explanations ? I would like to keep using MySQLi if possible. Old PHP: $conn = new mysqli($servername, $username, $password, $dbname); $conn->set_charset("utf8"); if($conn->connect_error){     die("Connection failed: " . $conn->connect_error); } $email = $_POST["email"]; $pw = $_POST["pw"];   $sql = "SELECT email FROM Users WHERE email = '" . $email . "'"; $query = $conn->query($sql); if(mysqli_num_rows($query) > 0){     echo "Record already exists"; }else{     $sql = "INSERT INTO Users (email, pw) VALUES ('" . $email . "', '" . $pw . "')";     if($conn->query($sql)){         echo "Update successful";     }else{         echo "Update failed";     }; } $conn->close();  New PHP: $conn = new mysqli($servername, $username, $password, $dbname); $conn->set_charset("utf8"); if($conn->connect_error){     die("Connection failed: " . $conn->connect_error); } $email = $_POST["email"]; $pw = password_hash($_POST["pw"], PASSWORD_BCRYPT);   $sql = "SELECT email FROM Users WHERE email = '" . $email . "'"; $query = $conn->query($sql); if(mysqli_num_rows($query) > 0){     echo "Record already exists"; }else{     $sql = $conn->prepare("INSERT INTO Users (email, pw) VALUES ('" . $email . "', '" . $pw . "')");     $sql->bind_param('s', $name);     $sql->execute();     $result = $sql->get_result();     if($result){         echo "Update successful";     }else{         echo "Update failed";     }; } $conn->close();

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


I am writing a platform independent Java console tool and within which will have to execute some commands in separate independent terminal at runtime.  However, I need to know which terminal should I be using gnome-terminal or xterm. i.e. the one available on that particular system. Since there are many different linux variants are available. I want to support at least the most obvious ones.  Normally in Java System.getProperty("os.name") returns Linux but it doesn't tell you if its Ubuntu or any other Linux varient. So It is difficult to know which terminal to start at runtime. Whether gnome-terminal or xterm or if there is anything else as well that I don't know.  Working sets:  In Windows:  cmd /c start java -jar jarTool arguments   In Ubuntu:  gnome-terminal --execute java -jar jarTool arguments   or  xterm -e java -jar jarTool arguments   Also just for additional information,I am using Runtime.getRuntime().exec(args or commands) to start terminal from Java program at runtime.

Say I need to write a script that will launch a terminal and execute a command and I need that to work on various systems. How can I do that in a safe and portable manner?  Is xterm always installed? I assume that any *nix with a GUI must have some terminal emulator. How can I get to it? Debian systems  x-terminal-emulator but that, apparently,  in Red Hat, let alone non-Linux *nixes.


git status command doesn't show new untracked directories and I can't git add them.. How can I resolve this? New and untracked files are shown, the problem is only with new directories.

How can I add an empty directory (that contains no files) to a Git repository?


We already have a  and the Canadian cell-phone marker is equally twisted with most carriers being helpful at telling what technologies and standards they use. As I am about to go to Mexico and would like to bring my Motorola Charm cellphone running on Rogers' network, this is perfect time to found out how to do this homework :)   Given an already-owned cellphone and which runs on an existing network. How does one find out if a phone will work on a specific destination country? How to find out if it will accept a local SIM which would give better rates  than roaming?   For using a local SIM, obviously assume the phone is unlocked. Mine is.

I've used my phone overseas with local SIM cards a lot, but recently had a surprising experience where one local SIM card simply wouldn't work with my phone but did work first time on my partner's, even though both were similar (unlocked Android phones) and another SIM card from a different local provider did work. Looking into it, it looks like there are various different standards around, but it all gets very technical very quickly.  Is there any simple way of looking up which SIM cards in a particular country will work with a particular model of phone, for calls, texts and internet access?


The points I recall:   colony on the moon populated by people that naturally just cause technological malfunction colony is self-sufficient: they charge earth-bound corps a testing fee on new tech one of the items under test is an airlock made up of a mesh of nanobots: you can just walk through and the nanobots seal around you   I read it once, enjoyed, want to reread and can't for the life of me google up the title or author.  Thanks in advance.  ...Stu

I am looking for the name and author associated with a story that I read in a magazine (probably Analog) in the mid 1990s.  The primary conceit was that there exist certain people around whom machines, computers etc. simply fail more often then they do when these folks are not around. There is a log-scale for denoting how strong the effect is.  Other useful tidbits:   It may have been one of a running time-line. It took place at a special facility on the moon---out of the way of others who might come to harm---with heavy redundancy of simple systems to provide atmospheric services, food, etc . and where these people have been (voluntarily, I believe) concentrated for research purposes. The narrator notes that everyone in this select group owns their own crowbar (using it to achieve egress from their own cubicle after a failure of the door...) It involved a nanotech spacesuit design. There is mention of a no-fly zone around the facility.


Is is optional for the author/illustrator to make character designs for all side characters?  Like in the case of anime adaptations, are some designs purely anime original

If it comes to light novels there are always some pictures that show a new character or scene. But when it comes to a character, who decides the design? For example, if I were an author and my work gets a publisher, then they would hire an illustrator. So when it comes to the design of a character (let's take character as a simple example) will the publisher decide that her hair is short and red or will the author decide that she has long, black hair? Also feel free to tell me some other example like maybe the illustrator can choose the design. :)


How do I test for items with a data value, like gray dye or purple wool, using the {Item:id} command?  I have tried using {Item:{id:minecraft:dye:7}} and {Item:{id:351/7}}

Let's say I want to track a group of players to see which one of them (if any) have a specific block type in their inventory that's of a specific datavalue; for instance Red Wool (minecraft:wool with a data value of 14).  I already know how to detect if a player has any wool in their inventory: /testfor @a {Inventory:[{id:"minecraft:wool"}]}. However, this doesn't discriminate between the various colours.  It'll find anyone with any colour wool, whereas I want to find only players with red wool.  I've tried modifying the data tag to also include a data value, such as /testfor @a {Inventory:[{id:"minecraft:wool",data:14}]} but this results in unmatched NBT tags and the  error message <Player> did not match the required data structure.  Obviously it's because data (or Data, damage, dataID, etc.) isn't the name of the NBT tag, or that the structure is wrong.  I realize I can accomplish this using the /clear command, but that's a bit clunky when running on a 20Hz /fill clock.  How can I filter out specific data values when using the /testfor or /scoreboard players commands?


I have a dual boot Ubuntu 18.04 and Windows10. Since 3 month, I use this configuration without any bug, but this morning, when I launch ubuntu from grub, no graphic interface appear just a terminal which ask me to type my login and my password. After this, I can use the terminal like all of the terminal and acceeded to my file but I haven't graphic interface. Does someone have a solution?

How to switch between virtual console and GUI in Ubuntu? I wanted to see what key functions would allow me to switch between the two.


Problem:     Prove that if the formula below makes sense, then   $$\DeclareMathOperator{\rank}{rank} \rank {AB} + \rank {BC}  \le \rank {ABC} + \rank B$$   I really don't know where to start. Can you give me a hint?

I was looking for an answer for this problem in terms of matrices, but I really don't know how to prove this result. The proposition says that:  Let $A\in M_{m\times k}(\mathbb{C})$, $B\in M_{k\times p}(\mathbb{C})$ and $C\in M_{p\times n}(\mathbb{C})$, then $\textrm{rank}(AB)+\textrm{rank}(BC)\leq \textrm{rank}(B)+\textrm{rank}(ABC)$


I have an Acer Chromebook C7. Intel processor. I am somewhat familiar with basic coding in the terminal and all that. I am not thrilled with Chrome OS, so I'd like a nice linux desktop/OS that I can run on it instead. A full OS would be great, but it would be nice if I could test out different options first. Regardless, I have looked everywhere and tried downloading a ton of different links and codes, installing to usb boot, etc. But I can't seem to get a recent Ubuntu with applications, internet, etc. Permissions or not being able to find the source or something always stops me from getting any release. How can I do it?

I have installed Ubuntu 13.04 on my desktop (runs like a charm). Then I used Crouton to install Ubuntu 12. 04 on my chromebook samsung (ARM). It also works quite well.  Here comes my question. Can we have a true Ubuntu (preferably 13.04) on my ARM chromebook?  It seems that the Crouton/Ubuntu is not 100% the real thing.  The best option would be to have the full Ubuntu 13.04 and remove the Chrome OS.


I frequently see the abbreviation "No" to mean "Number" (or "Nos" to mean "Numbers") instead of the much more common meaning of the word (a negative statement or denial).  Sources cited  say it's the correct abbreviation, but don't really explain why it got that way or why it remains true today.   This seems odd because of (a) the strong negative association with that choice of abbreviation, especially when letters are used instead of a , (b) the availability of other abbreviations like "Num." or "Nr." or "#", and (c) the fact that the English word "Number" doesn't have an o in it (the abbreviation makes more sense in Spanish, for example, as short for "Numero," but even there it's  not used without superscripts due to confusion with "no" as a negative word).   Why does English use "No." as an abbreviation for "Number?"

Why the disparity? And why use 'No.'? Is it from the French?  And the hash or pound sign seems a weird choice too, is there a history or any reason involved?


The moment of inertia of a massive object about a given axis describes how its mass is distributed about that axis. I understand that a rotating black hole of a given mass and angular velocity possesses angular momentum, and one would think that it therefore possesses a certain moment of inertia about its axis of rotation. My question is this: can knowledge of that moment of inertia tell us anything about how the black hole's mass is distributed about its axis of rotation?

My question is in the title: Do black holes have a moment of inertia?  I would say that it is: $$I ~\propto~ M R_S^2,$$ where $R_S$ is the Schwarzschild radius, but I cannot find anything in the literature.


Assume that we have a $K_{17}$ and we color every edge of it with 3 colors ( Like Red, Blue & green ).    Prove that for every coloring of $K_{17}$ with 3 colors, After coloring, We have a one-color $K_3$.    Note 1: What i tried is that i picked and vertex like $v$ and i fixed it.  Then I said this vertex is connected to $16$ other vertices ($v_1,\cdots,v_{16})$. By the pigeonhole principle we know that there exists a color that at least 6 of the edges between $v$ and $v_i$'s. Without loss of generality, We say that color is blue and that 6 vertices are $(v_1,\cdots,v_6)$. Now we see the edges between $v_i$'s. If there exists a blue edges between these vertices, We are done !  What i'm stuck on is what to do if there is no blue edge between $v_i$'s.    Note 2: Don't use ramsey numbers.  Thanks in advance.

If the edges of the complete graph $K_{17}$ (on 17 vertices with no three collinear) are each colored one of three colours can it be proven to have two or more monochromatic triangles?


My use case is that our Salesforce org will do callout to external system at different times of the day. All these data are stored in a custom object, which basically stores the external system URL and the time at which salesforce needs to do callout. Currently, I have around 15 such records, which may increase or decrease in the future. One option I have is to create a separate batch job for all the records to do callout. That means I need to write a 15 batch job. I'm looking for is a way where I can do all callout from one single batch by scheduling it dynamically at different intervals of time.

I've recently run across multiple needs to execute multiple different batch jobs at the same time, and almost immediately hit the (somewhat inexplicable) SFDC limit of 5 batch jobs queued at once.  I've worked around this limit in a number of ways, none of which seem ideal to me.   returning a Iterable<SObject> from the start method, which contains a mix of all the SObjects I need to act upon, and then use dynamic inspection to figure out what I'm supposed to be doing on each row in the execute method. This seems fine for small jobs, but wouldn't presumably scale to millions of records due to heap size etc. using a scheduled apex job that runs once, executes a batch, and then that batch in its finish method schedules another apex job (to run in say 1 minute) that executes the next batch in the chain, and so on.   Is there a more viable/flexible pattern that I could be using? What I really need is a flexible work queue where on-demand, not-very-time-sensitive batch jobs can be queued for future (serial) execution based on user activity. And that doesn't violate platform limits of batch jobs or scheduled jobs - really needs to contribute a max of 1 scheduled or batch job at any given point.  Not sure it will help, but the characteristics of the job set I'm envisioning are this:   each task executes on a single SObject type and does one job: e.g. setting unset fields, doing fake M-D rollups, etc. some tasks are operating on a small subset of a table, others need to walk over every Contact/Lead/etc. with potentially millions of rows per batch job. while some tasks are known to be needed every N hours / days, most of them are needed only after some user-driven operation: e.g. click a big red button in an admin console, do something to more than N records, or a new/updated record of a certain type requires its downstream records to be operated upon.


I have been trying to disable Microsoft Edge on my computer for some time and believe I need to resort to having it automatically closed on runtime. The idea would be to render Edge unusable, while it still being present on the system (since it is not possible to remove). I am able to have a task run on Task Scheduler, but beyond that will I need clear instruction and possible links to tutorials. I have asked a  but it was ineffective (either me or the code itself- my question may not have been clear). Keep in mind in your answer I have no experience with CMD or PowerShell and so all instructions will have to be made very explicit.

I want to disable the new Microsoft Edge running on an HP laptop equipped with Windows 10.  Various instructions say select the Microsoft Edge folder, right click the mouse, and then rename the folder.  However, the "rename" option does not appear after right-clicking.


How do I log on to my root account when I turn on my computer instead of logging on as an ordinary user? This means that when I log in with my root account, any software is opened by default root and has all the rights to the file.

I want to login as root, but when I enter   sudo -s   and enter password, this message is shown: "you are not in sudoers file", and when I enter   su   and enter password, this is shown: "authentication failure".  My os has one account only. about past1 hours ago I log on as root and do some commands , when I logout , I can't login another time!


Unity's physics engine isn't deterministic (ie. the results aren't always the same on all computers) so I haven't Idea that how billiard games Implemented.Is there a way to Implementing fake and deterministic  physic in unity? I mean I want to make billiard without using Rigidbody    I found this open source project that didn't use physic! this is what I need but unfortunately it's full c++ and I haven't enough time to convert it to c#

I'm making a billiard game and I have two questions:  How do I find the velocity of two balls when they collide with each other and how do I apply it to both balls?  I already know the angles that they're gonna move, I just need to find the velocity that they'll move in those directions.  My game is in 3D, and I'm using Unity. I don't want to use Unity's built-in physics to compute the result in this case, I'd like to know how to compute it myself.


I am trying to rename files in src folder bitcoin/src by using:  find . -exec rename 's/bitcoin/altcoin/' {} ";"   also tried:  find ./ -type f -readable -writable -exec rename -e 's/bitcoin/altcoin/g' {} \;   and I got this:  find: ‘rename’: No such file or directory   I am trying to fork bitcoin to my own altcoin, using Ubuntu 18.04!  What's the problem and how can I fix it?

I'm trying to to execute a script, which uses the command rename.   When I execute it, I get a message rename: command not found. Any ideas?   if [[ -z '$3' ]]; then     shopt -s dotglob     rename "$EXPRESSION" ./* else     rename "$EXPRESSION" "$3" fi


What is correct : 72 hour or 72 hours? In a article I have seen 72 hour rather than 72 hours.

Being a non native speaker of English, this type of sentence always bites me:     It was a pleasant four hours journey from Nashik to Pune.   Should it be hour or hours?


In uniform circular motion, the force is perpendicular to the instantaneous direction of motion. So work done is zero. But if an object is in elliptical orbit such as a planet, I find it hard to understand how the force is perpendicular to direction of motion. And if it is not, some work is done which also doesn't seem to make sense.

As we know, the velocity of the planet changes as it orbits around the sun, both in its magnitude and direction. The centripetal acceleration causes the change in the direction of velocity but I want to know what is the tangential force that acts on the planet to change the velocity by its $magnitude$. The answer normally as to why the speed changes is: If  the  force  that  the  Sun  exerts  on  the  planet increases  (as  the  planet moves closer),  then  the acceleration   of  the  planet must  increase,  resulting  in a  higher  orbital  speed,  and vice  versa. But this force is not along the body but towards the sun. So such a force should only change its direction.


We say that a sequence $\left\{y_n\right\}$ is a rearrangement of a sequence $\left\{x_n\right\}$ if there is a 1-1 correspondence $f : \mathbb{N} \rightarrow \mathbb{N}$ such that $\forall$ $n \in \mathbb{N}$, $y_n = x_{f(n)}$. Suppose $\left\{y_n\right\}$ is a rearrangement of $\left\{x_n\right\}$. Prove that $\left\{y_n\right\} \rightarrow L$ iff $\left\{x_n\right\} \rightarrow L$.   1) How do I prove this ?

Is this statement true? i.e. If $f(n)$ is injective and $p_n \rightarrow L$, does $p_{f(n)} \rightarrow L$?? (I realize that it's technically only a rearrangement if $f(n)$ is bijective.)   My attempt at a proof:  Since $p_n \rightarrow L$, we have that, for all $n$ except $n \le N$, $d(p_n, L) < \epsilon$.  Let $S = \{n \ | \ f(n)\le N\}$, let $n_0$ be the largest $n \in S$, we know there is such a largest $n$ because $f(n)$ is injective. Now we have that $\forall \ n > n_0 \ f(n) > N$ which implies that $p_{f(n)} \rightarrow L$, as required.  Is this correct? Does my proof work?


Using substitution with $u=\sin{x}$, The integral of $\sin{x}\cos{x}$ is equal to $\frac{1}{2}\sin^2{x}$. This is the solution I require.  However, why is it that when I use the double angle formula $\sin{2x} = 2\sin{x} \cos{x}$, and integrate $\frac{1}{2}\sin{2x}$, I get a completely different answer of $-\frac{1}{4}\cos{2x}$ even though $\sin{2x} = 2\sin{x} \cos{x}$.

$$ \int \sin \theta\cos \theta~d \theta= \int \frac {1} 2  \sin 2\theta~ d \theta=-\frac {1} 4  \cos 2\theta$$ But, if I let  $$ u=\sin \theta , \text{ then }du=\cos \theta~d\theta $$ Then $$ \int \sin \theta\cos \theta~d \theta= \int u ~ du =\frac { u^2 } 2 =\frac {1} 2 \sin^2 \theta $$ Since $$ \sin^2 \theta =\frac {1} 2 - \frac {1} 2 \cos 2\theta$$ The above can be written as $$ \int \sin \theta\cos \theta~d \theta= \frac {1} 2 \sin^2 \theta =\frac {1} 2 \left( \frac {1} 2 - \frac {1} 2 \cos 2\theta \right)=\frac {1} 4-\frac {1} 4 \cos 2\theta   $$ Why are the two results differ by the constant $1/4$? Thank you.


I am getting this error when I try to run this query. I am drawing a blank on why this is happening. Everything else is running correctly. Any help or advice would be appreciated.      COUNT(Allergies_Types__c) childDairy FROM Child_Consent_Form__c                                              ^ ERROR at Row:9:Column:75 Didn't understand relationship 'Child_Consent_Form__c' in FROM part of   query call. If you are attempting to use a custom relationship, be   sure to append the '__r' after the custom relationship name. Please   reference your WSDL or the describe call for the appropriate names.                SELECT                      puLocation__r.Name LocationName,                      puLocation__r.notes__c LocationNotes,                     puLocation__r.Milk_Location__c MilkLocation,                     puLocation__r.Location_type__c LocationType,                     Child_Consent_Form__c.Active_Inactive__c,                     count(ID) numberofchildren,                     count(Allergies__c) childrenwithalergies,                     (SELECT COUNT(Allergies_Types__c) childDairy FROM Child_Consent_Form__c                         WHERE Allergies_Types__c INCLUDES ('Dairy-free'))              FROM Child_Consent_Form__c               WHERE     Child_Consent_Form__c.Active_Inactive__c = 'Active'              GROUP BY puLocation__r.Name,                        puLocation__r.notes__c,                       puLocation__r.Milk_Location__c,                       puLocation__r.Location_type__c,                       Child_Consent_Form__c.Active_Inactive__c

Say I have a master-detail relationship between two objects, Schematic__c and Part__c.  I can SOQL query the master from the detail: [SELECT Schematic__r.Name FROM Part__c]  If I'm building a query from strings, I resolve the schema name, for example in a managed package:  SObjectType.Part__c.Fields.Schematic__c.Name //gives me 'ns__Schematic__c'   But when traversing into the master object, the __r relationship suffix is what I need to surface. I've toyed around with the obvious Schema.SObjectType variations but I'm not having much luck:  SObjectType.Part__c.Fields.Schematic__r.Name //Schematic__r is not a field of ns__Symbol__c   What's the correct way to resolve the ns__Schematic__r.Name token without replacing the suffix?


Can anybody help me ? Which is correct ?     Each of the actors did their part well. or Each of the actors did his part well.   Thanks in advance.

I often use  to keep my sentences gender neutral. Many of my friends (none of them are native speakers), however, consider this to be grammatically incorrect, and suggest me not to use it in formal English exams.  My questions are:   Is singular they widely accepted in English speaking countries such as America and Britain? Is it formal enough to be used in formal situations, such as a public speech? Is it casual enough to be used in informal situations, such as gossiping among friends?


Somebody (not a native speaker) told me that "I was with my sister" is grammatically incorrect and the present perfect tense should be used instead ("I have been with my sister"). Is this true?

I have read many online articles. I've read questions and answers on this site. I still can't get my head wrapped around the difference between past simple and present perfect  I know the difference is between finished time (use past simple) and unfinished time (use present perfect). But as a non-native English speaker, this still makes no sense to me. I am not implying any kind of time period.     I have posted on SE   I posted on SE   I just want to convey that the action completed in the past. I don't want to provide any connotation whether the action just completed, or completed at certain period in past.  Maybe with "I", I know the time period, but what if I am talking about someone else.     He has posted on SE   He posted on SE   I don't know the time frame that "he" did the action. I don't know what "he" was planning (continuous action, or at specific time). I just know the action took place in the past. I don't know if it just finished. I don't know if there is a consequence to the action or not.  It seems to me that I am forced to imply a time frame. So my question is: if I don't want to imply any time frame, or at least to imply as little as possible, what should I use?


I have found  which is most probably . There is a bounty of 50 rep (not much I know..)  Is still would be interested in what happens, if none answers the question, but it is flagged and confirmed as duplicate

It's possible to offer and award bounties of reputation on questions.   What is a bounty? How can I find questions that have a bounty attached? How do I start a bounty? When can I start a bounty? Why is the system requiring me to choose a bounty amount that's higher than the minimum? Can I use Markdown formatting in the bounty remarks? Can I edit the remark? How long is the bounty period? How do I award a bounty? Can I award a bounty to my own answer? Can I award a bounty to an old answer? If I offer a bounty on someone else's question, can I award the bounty to their answer? After awarding the bounty, can I remove it or move it to another answer at a later time? What happens if there's no answer after the bounty period? What happens if I feel my question is still unanswered? What is automatic awarding? Are bounty awards exempt from the 200 points/day reputation limit? How does Community Wiki mode affect bounties? How does user deletion or post dissociation affect bounties? Can I award a bounty to an answer from a deleted user or one where the author was dissociated? Can I offer a second bounty after the first one has expired? Can I raise my bounty? What happens if a bounty question is closed or deleted? Why can't I vote to close or migrate a bounty question? What happens if I delete my account while I have an active bounty? Do I keep an awarded bounty when I delete my answer? What happens if a question where I awarded a bounty later gets deleted or migrated? Can I cancel my bounty? Can I affect / divide / share part of my bounty to two (or more) users? How many outstanding bounties can a single user have?      See also:  in the Help Center


I had Windows 7 installed on my laptop, with hard drive partitioned. I installed Ubuntu formatting the drive as it didn't detect I had Windows 7 too already. It installed correctly, but now when I'm also trying to install Windows I don't have a drive of NTFS file system as it converted to ext4 completely (all 500 GB WD). Please help me in installing Windows too.

I have Ubuntu on my laptop. Now I want install Windows 7 in a dual-boot. How can I do this? I can't lose my Ubuntu files, and I'm afraid that I might break . Go  for UEFI only!


I am trying to write a query in Oracle which will return max value. I have 3 tables Employee, customer , orders.  SELECT a.ID_Employee, a.NAME, a.SURNAME, SUM(c.value) AS "value"  FROM Employee a, CUSTOMER b, ORDERS c WHERE a.ID_Employee = b.ID_Employee and b.ID_CUSTOMER = c.ID_CUSTOMER group by a.ID_Employee, a.NAME, a.SURNAME ;   The result of questions :  id_Employess Name  Surname  Value 7654         KENNETH MARTIN 27348 7555         DANIEL PETERS  11060 7820         PAUL   ROSS    20796,8 7844         MARY   TURNER  58055,9 7560         SARAH  DUNCAN  36191,2 7521         CYNTHIA WARD   9984,2 7499         KEVIN  ALLEN   7870,8 7789         LIVIA  WEST    32274,2 7557         KAREN  SHAW    33655,65   And i need max value from this result should be :   id_Employess Name  Surname  Value 7844         MARY   TURNER  58055,9

Table:   UserId, Value, Date.   I want to get the UserId, Value for the max(Date) for each UserId. That is, the Value for each UserId that has the latest date. Is there a way to do this simply in SQL? (Preferably Oracle)  Update: Apologies for any ambiguity: I need to get ALL the UserIds. But for each UserId, only that row where that user has the latest date.


The problem of question mark in citation can be solved by compiling using Latex+Bibtex+Latex+Latex locally. However, it doesn't help when I submit the .tex file to a online editorial system of a journal. The conversion engine of the system can only do a single-time compiling so that the question marks are always there. The system only allows to upload .tex file, not supporting other types. Does anyone know any solution to this? Thank you!

I need to submit my TeX file to journal but they request     Do not include a separate .bib file or .bbl file with your submission   and     please run BibTeX before submitting your paper, and include (read-in) the resulting .bbl file within the reference section of your paper   If I upload a TeX file but not the .pdf file including the .bib results. How should I merge my .bib file  with my TeX file ?


Let $M(n;R)$ denote the set of all $n×n$ matrices with real entries (identiﬁed with $R^{n^2}$ and endowed with its usual topology) and let $GL(n;R)$ denote the group of invertible matrices. Let G be a subgroup of $GL(n;R)$. Deﬁne   $H$ = { $A \in G$ : there exists a continuous function $f$ from $[0,1]$ to $G$ and $f(0) = A$ and $f(1) = I$.}  Then $H$ is a normal subgroup.  Can I do it by not using topological group?

Let $M(n;\mathbb{R})$ denote the set of all $n \times n$ matrices with real entries (identified with $\mathbb{R}^{n^{2}}$ and endowed with its usual topology) and let $GL(n;\mathbb{R})$ denote the group of invertible matrices. Let $G$ be a subgroup of $GL(n;\mathbb{R})$. Define $$H = \biggl\{ A \in G  \ \biggl| \ \exists \ \varphi:[0,1] \to G \ \text{continuous such that} \ \varphi(0)=A , \ \varphi(1)=I\biggr\}$$  Then is $H$ normal in $G$?  For proving $H$ normal i should verify two things:   First $H$ is a subgroup. For all $A \in G, B \in H$, we must have $A \cdot B \cdot A^{-1} \in H$.   That's it i  am not able to proceed any further.


What is the correct spelling of Marshalling/Marshaling? I also have problems with other derived variants of marshal:   marshaller / marshaler marshalling / marshaling marshalled / marshaled   Google hasn't help much, also different spell checkers have different opinions.   What are the rules here?

Some verbs can have double Ls in the gerund form; for example:   modeling; modelling   traveling; travelling   Which form should we use, or which form is used more in the literature?


What is the result of unpacking? I thought the unpacking result is a first class citizen that I can use as an object. >>> print(*range(5)) 0 1 2 3 4  However, apparently it cannot be evaluated to be an object and I cannot get its type. So, I wonder what is the unpacking operation generating? >>> *range(5)   File "<stdin>", line 1 SyntaxError: can't use starred expression here  >>> type(*range(5)) Traceback (most recent call last):   File "<stdin>", line 1, in <module> TypeError: type() takes 1 or 3 arguments  >>> *values, = 1,2,3  >>> values [1, 2, 3] >>> *values   File "<stdin>", line 1 SyntaxError: can't use starred expression here

In the following method definitions, what does the * and ** do for param2?  def foo(param1, *param2): def bar(param1, **param2):


Noether's Theorem states that if a Lagrangian is symmetric for a certain transformation, this leads to an invariant: Symmetry of translation gives momentum conservation, Symmetry of time  gives Energy conservation etc.  The Galilean principle stating that all reference frames that move with constant speed relative to each other are equivalent is also a symmetry principle: Setting up a physical system that is identical to the original except for a constant velocity (boost) added will have the same behaviour.  Shouldn't there be an invariant associated with this symmetry? If yes, what is that invariant?

Noether's Theorem is used to relate the invariance of the action under certain continuous transformations to conserved currents. A common example is that translations in spacetime correspond to the conservation of four-momentum.  In the case of angular momentum, the tensor (in special relativity) has 3 independent components for the classical angular momentum, but 3 more independent components that, as far as I know, represent Lorentz boosts. So, what conservation law corresponds to invariance under Lorentz boosts?


Can you tell me whether COSN () is a good conference? Its a new conference introduced by ACM with a strong PC committee. Last year, the acceptance rate was around 16%. I have recently finished a manuscript that I would like to try in either COSN, or WISE () which is an established rank A conference. Can you tell me which one will be a better venue in terms of exposure/visibility? My manuscript is on social network mining which is within the scope of both conferences.

Nowadays, in almost every scientific field, there are hundreds of conferences. Many call for papers emails fill our mail boxes.  Freedom of choice is great, but, how to choose to which conference send a paper?  Should I choose one...   based on the scientific relevance? based on the scientific vicinity to your paper theme? based on its prestige? because of some official ranking? because it provides the best food?


Installing Ubuntu 14.04 inside Windows 8; can anybody help me? Is it safe to install Ubuntu inside Windows 8? I am not getting info about installing Ubuntu in Windows 8. In Windows 7 we can use Wubi, but what about with Windows 8?

I have Windows 8 Release Customer Preview on my laptop. I tried to install Ubuntu on it with Ubuntu Windows installer (I have always used this to install, although that was on Windows 7), it installs and asks to reboot, then immediately Windows 8 boots up.  I do not have the option to choose what OS to boot. How can I boot to Ubuntu? VM is not exactly what I would like to use, but it is an option, however a last resort. Any help?


I know that some adjectives are written after the hyphen "-" like sentence one below. Actually I don't know the grammatical rule behind that, but could I replace sentence one with sentence two?     They are genes-related issues. They are genes-relevant issues.

Should I use a hyphen to connect the following words? What is the general rule about that?  environment friendly  -->  environment-friendly frontend   --> front-end backend   --> back-end speedup   --> speed-up


A  brought up a particular quote that made me wonder about Professor Quirrell's character. The quote is from Dumbledore:     Quirrell, full of hatred, greed and ambition, sharing his soul with Voldemort, could not touch you for this reason. It was agony to touch a person marked by something so good.”    - Harry Potter and the Philosopher's Stone, Chapter 17 (The Man with Two Faces)   Was Quirrell full of hatred, greed, and ambition because he was sharing his soul with Voldemort? My recollection of Quirrell's background is a little hazy but I thought he was generally regarded as a smart wizard but had something to prove. Which is why he went hunting vampires and ended up being possessed by Voldemort. I don't recall any background of him being power hungry or having any major character flaws that would imply he would want to help Voldemort come back to power.  How much of Quirrell's actions were controlled by Voldemort as opposed to Quirrell acting of his own free will? What motive did Quirrell have to kill Harry Potter / help Voldemort?

Can it be inferred from canon whether Quirrell was a willing host to Voldemort? Was he a supporter of him before he became his host?  If he was tricked, for example, by meeting a weakened, ghostly form of Voldemort who promised great reward for helping, and then afterwards he was just forced to do all the evil he did, I would not count it as being a willing host.


If I have function:  function Thing( name_of_thing ) {     this.name = name_of_thing; }   Is there a way to know if invoked by:  var my_thing = new Thing( 'Something' ); // result: { name: "Something" }   versus:  var my_thing = Thing( 'Something' ); // result: undefined

Given a function:  function x(arg) { return 30; }   You can call it two ways:  result = x(4); result = new x(4);   The first returns 30, the second returns an object.  How can you detect which way the function was called inside the function itself?  Whatever your solution is, it must work with the following invocation as well:  var Z = new x();  Z.lolol = x;  Z.lolol();   All the solutions currently think the Z.lolol() is calling it as a constructor.


How do I change the specific tags of the questions and answers I receive in the monthly newsletter? Much appreciated.

Stack Overflow is huge and varied. Wouldn't it be great if I could just subscribe to a newsletter with a list of my favorite tags? If I love dealing with , I think it would make sense for my version of the newsletter to focus more on Android questions.  Or, if I sign up for the  newsletter, but don't own a Mac, it would be nice if I my newsletter would focus on the part of the site I do follow (i.e., iOS).  So I would like to suggest that the newsletters for each site (optionally) take into account the user's favorited and ignored tags for that site.  I know that you can receive emails about specific filters, but I don't think that's a good solution for users who already receive the newsletter. Most of the questions it highlights cover topics that I have no interest in. It would be much better if I could filter out all the noise and get down to my likely favorites.


How to prove this inequation. $$(\frac{n}{m})^m\le C_n^m\le(\frac{en}{m})^m$$ where $0<m\le n$ and $C_n^m$is the Combinatorial number. I tried to prove the left part by using the convexity of $\ln$, but it can't work on the right part. the proof of the left part: $$ \ln(\frac{n}{m})^m=m(\ln n-\ln m) \\ \ln C_n^m=\ln n + \cdots+\ln (n-m+1)-\ln m - \cdots \ln 1=\sum_{i=1}^m(\ln (n+i-m)-\ln i) $$ Due to the convexity of $\ln$ function: $$\ln n-\ln m \le ln (n+i-m)-\ln i$$ so： $$\ln(\frac{n}{m})^m \le \ln C_n^m$$

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?


My laptop is dual booted with Windows and Ubuntu. I have updated my Ubuntu grub by the sudo update-grub. Now, when I rebooted my laptop, it is not showing the grub screen where I can access my windows OS.

I installed Windows 7, which ate Ubuntu's boot file. When starting up the computer, it now goes straight to Windows, without giving me the option of booting Ubuntu.   How can I get Ubuntu back?


On Android App I am not able to go to question that I have marked as favorites. Did you forget add this section on Android App or it is so hidden?

I know there is a way to  from the app, but I cannot find a practical way to  follow the activity on the questions I favorited.  The only way I found was to type infavorites:mine into the search box and sort by active. But there is no way to bookmark a search, and repeatedly typing this search command on a small screen is no fun.   I understand not all desktop site features can be built into the app. But following the activity on my favorite questions is precisely the sort of things I'm likely to do from a mobile device.


So I'm designing a CD cover for my friends band. And I will have to use a photo of them for that cover. How am I supposed to create it so that it won't pixelize if they want to use that for a big advertisement (like a billboard or something simmilar). Sorry for my english, it's not my native lanugage :)

For wall-sized graphics and large banners (e.g. 3m × 5m), what is an acceptable PPI for print? As I understand it 300 ppi is the typical for 'small' artworks (esp. for clean text resolution). However, for small artworks, the audience usually engages at a much closer distance. Therefore, in the interests of keeping a bitmap file down to a reasonable size, can you get away with a much-reduced PPI for a large format/banner print?


The new service was expected to be a success; __________ very few customers upgraded their accounts.   My student chose "although" for the blank but "yet" is correct. What is the grammatical reason for that?  This is a  from the Reading section (part 5).   Any help with this question is appreciated!

The new service was expected to be a success; ____very few   customers upgraded their accounts.  A. yet   B. just   C. moreover    D. although   In this sentence, I am confused between “yet” and "although". I think although is more correct, but the answer is yet. Please help me make clear about the usage of yet. Thank you very much


Can someone explain how to prove the following identity involving Fibonacci sequence  $F_n$  $F_{2n} = {n \choose 0} F_0 + {n\choose 1} F_1 + ... {n\choose n} F_n$ ?

Prove: $\binom{n}{0}F_0+\binom{n}{1}F_1+\binom{n}{2}F_2+\cdots+\binom{n}{n}F_n=F_{2n}$;  I was stuck with this question for a while... Help me please!!! Thanks!!!


Some spells like  and  specify that only an unwilling creature makes a saving throw:     If the target is unwilling, it can make a Constitution saving throw.    and     An unwilling creature must make a Wisdom saving throw to avoid the effect.   ... but is an unconscious character able to make this judgment (and therefore be eligible to make a saving throw)?  Mind you, I've seen  on opting in to certain spells, but I'm specifically asking about opting out so as to be eligible for the saving throws.

This situation came up last week during our session. The party was facing a pretty difficult mob of enemies and one of the party members was knocked unconscious. Seeing the situation worsening, one of the players decided to use the  (DMG p. 197). In the text, it says:     The rod then instantly transports you and up to 199 other willing creatures you can see to a paradise that exists in an extraplanar space.   At first glance I thought this was actually a pretty good time to use the rod. The question came up though, what about the party member who is unconscious? In the end I made the call that the character went with them to keep things moving and more fun.  However, I'm feeling like back pedaling a bit and notifying my players that for future uses, the line "... willing creatures..." will be more strictly enforced as I don't feel like an unconscious creature could be willing.  Did I handle this the right way?


Find a basis for the vector space of symmetric matrices with an order of $n \times n$  This is my thought: by definition of symmetry, $a_{i,j}=a_{j,i}$. Therefore, the basis should consist ${n^2-n} \over 2$ matrices to determine each symmetric pair. In addition, it should also consist $n$ matrices to determine each term in the diagonal.    Therefore, the dimension of the vector space is ${n^2+n} \over 2$.   It's not hard to write down the above mathematically (in case it's true).    Two questions:     Am I right? Is that the desired basis? Is there a more efficent alternative to reprsent the basis?     Thanks!

Describe a basis for the vector space of symmetric n x n matrices. What is the dimension of this space?


Let $A$ and $B$ be two $n$-by-$n$ real matrices such that $A+B = AB$.   How do I prove that $AB= BA$?   I have tried using the trace function on $A+B-AB$. But I could not get any Ideas. Kindly provide me with hints.

$A$ and $B$ are $n\times n$ matrices and $A+B=AB$. I have an interesting proof that this implies $A$ commutes with $B$, but the proof only works when $||B|| \lt 1$. I'm looking for a way to salvage the proof so that it works for all $B$.  $$A=AB-B$$ $$A=(A-I)B$$ by repeatedly substituting $A$ with $(A-I)B$ on the RHS, $$A= (A-I)B^N - \sum_{i=1} ^{N-1} B^i$$  Since the space of $n\times n$ matrices is Banach (hence complete) under the standard operator norm, the limit $\sum_{i=1}^{\infty}B^i$ is well defined given $||B|| \lt 1$. Hence, taking the limit as $N \rightarrow \infty$, $$A =  -\sum_{i=1}^{\infty}B^i$$  Now the LHS commutes with B, hence so does the RHS.    Is there some trick to extend the method to work with any $B$ where $||B|| \geq 1$? I know that the result is true due to another simple algebraic proof, but I'd like to see if this method can be salvaged.


I am giving my old laptop to my brother and am trying to change everything to his name. I have tried every online tutorial I could find and nothing has worked so far. I need to change allie@Nolan's Machine:~$ to Nolan@Nolan's Machine:~$

I have accidentally typed my name wrong when I created the administrator account. Although I managed to change the user name at the login screen, I am unable to rename the /home/oldusername to /home/newusername. I tried most of the online tutorials, and it failed.  The code I tried was this:  usermod -l newusername -m -d /home/newusername oldusername   But the output is:  cannot lock /etc/passwd; try again later.   How can I fix the issue and change the folder to newusername and expect all the applications to work as before?


I am considering buying a 13" MacBook. Please note that this would be my first Apple device. The two the options that I am considering are:   MacBook Air, 2013, 13", 128GB SSD, 1.4GHz dual-core Intel Core i5, 4GB DDR3 MacBook Pro with Retina display, 2013, 13", 128GB SDD, 2.4GHz dual-core Intel Core i5, 4GB DDR3   There are some issues that I am concerned about:   Performance Is the 128GB enough? (How much would the OS take up of this?) The MacBook Pro seems to be quite tough. Does it also apply to the Air? I am also interested in Windows alternatives... I am looking for "13 ultrabooks with long battery life + SSD and decent computing power. Could you recommend any? In general, what are the pros and cons of MacBook Air vs. Windows ultrabooks?   Thanks a lot

I can see that the 13" version of MacBook Pro and MacBook Air is same $1199, but the Pro is more feature-loaded than Macbook Air. Why would anyone buy MacBook Air? What's the catch in this?    I was thinking of buying a MacBook for development purposes, and worried if there's any problem in the Pro version, because it comes with more features (like more storage).  Edit:    Thanks for the answer guys, I bought a MacBook Pro a week ago and already loving it.


How do you prove that $$\lim_{n \to 0}\frac{\cos(n)-1}{n}$$ equals to $0$? I can't use L'Hôpital's rule because when differentiting cosine using $$\lim_{h \to 0}\frac{\cos(x+h)-\cos(x)}{h}$$ we get that exact limit at some point. I assume we have to use the squeeze theorem.

I know with l'Hopital's rule it becomes $-\sin(x)$ which has the limit $0$. However, I have been wondering how to evaluate this limit without l'Hopital's rule.


I'm looking for a import Aes Ctr on c# I have found this code that working great but it is in Javascript, somebody know if there is corrispettive on c#?  Aes builtin on c# is not the same I have just tried it.    I tried this code:  but I don't have same output on original javascript.  Thanks for help.  It is not the same of other question () cause there isn't IV and Key.

I can't seem to find a nice clean example of using AES 128 bit encryption.  Does anyone have some sample code?


it has been a while I used ubuntu for my daily driver because of me needing VST files in music production, recently picked up this thinkpad.  Anyways, whenever I try to download something from youtube this error shows up  ERROR: Signature extraction failed: Traceback (most recent call last):   File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 905, in _decrypt_signature     video_id, player_url, s   File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 797, in _extract_signature_function     raise ExtractorError('Cannot identify player %r' % player_url) ExtractorError: Cannot identify player u'/yts/jsbin/player-vflAmElk-/en_US/base.js'; please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; see  https://yt-dl.org/update  on how to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.  (caused by ExtractorError(u"Cannot identify player u'/yts/jsbin/player-vflAmElk-/en_US/base.js'; please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; see  https://yt-dl.org/update  on how to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.",)); please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; see  https://yt-dl.org/update  on how to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.   I had been using the same code my past using ubuntu 12.04. what do I miss?  youtube-dl --extract-audio --audio-format mp3 <url>

I use youtube-dl to download videos for watching later offline. Usually, it works fine. However, due to frequent changes on the video sites, it sometimes requires a quick update. It wasn't a problem before on 13.04 but after upgrading to 13.10, I get  # youtube-dl -U It looks like you installed youtube-dl with a package manager, pip, setup.py or a tarball. Please use that to update.   I tried updating it via apt-get but there is no new package. So the app's update mechanism has been disabled and the maintainers aren't keeping up, what is the solution? How do I update it?  And why was it changed at all? It was updating a package manager version just fine in raring.   I'm already running into compatibility problems.   $ youtube-dl "http://vimeo.com/55784152" [vimeo] 55784152: Downloading webpage [vimeo] 55784152: Extracting information ERROR: Unable to extract info section; please report this issue on https://yt-dl.org/bug . Be sure to call youtube-dl with the --verbose flag and include its complete output. Make sure you are using the latest version; type  youtube-dl -U  to update.   QUICK UPDATE:  As requested,  # type youtube-dl youtube-dl is hashed (/usr/bin/youtube-dl)  # apt-cache policy youtube-dl youtube-dl:   Installed: 2013.08.29-1   Candidate: 2013.08.29-1   Version table:  *** 2013.08.29-1 0         500 http://pl.archive.ubuntu.com/ubuntu/ saucy/universe amd64 Packages         100 /var/lib/dpkg/status


I want to get the href-link from this:
test1

test2
    I'm trying this:  var nodes = doc.DocumentNode.SelectNodes("//a[@class='abc']/@href");   ...InnerHtml becomes
test1

test2
, not the link in the href...

I'm trying to retrieve a specific image from a html document, using html agility pack and this xpath:  //div[@id='topslot']/a/img/@src   As far as I can see, it finds the src-attribute, but it returns the img-tag. Why is that?  I would expect the InnerHtml/InnerText or something to be set, but both are empty strings. OuterHtml is set to the complete img-tag.  Are there any documentation for Html Agility Pack?