Good morning :)  So I had an exercise, which asks "how many monic irreducible polynomials are there of degree 3 over the finite polynomial ring $\Bbb F_p[X]$, where $p$ is some prime?"  I was wondering if you can do this via counting?  I know that there are $ p(p-1)/2$ monic irreducible polynomials of degree 2 over $\Bbb F_p[X]$.  And then I counted how many reducible polynomials of degree 3 there are, which is:  A reducible polynomial of degree 3 has to have at least one linear factor.  Then we have 4 options:  1) $(X-a)(X^2 + bX + c)$, where the quadratic term is irreducible. => There are $p^2(p-1)/2$ polynomials of this form.  2) $(X-a)^3$ => p polynomial of this form.  3) $(X-a)^2*(X-b)$, where $a$, $b$ distinct => $p(p-1)/2$. polynomials of this form.  4) $(X-a)(X-b)(X-c)$, where $a, b, c$ pairwise distinct => $p(p-1)(p-2)/6$ polynomials of this form.  And in total I have $p^3$ possible monic polynomials of degree 3 with coefficients in $\Bbb F_p$.  So then the number of irreducible, monic polynomials of degree $3$ over $\Bbb F_p$ is  $p^3 - (p^2(p-1)/2 + p + p(p-1)/2 + p(p-1)(p-2)/6) = p(p-1)(p+3)/3$ when I count it.  However I know the correct solution is supposed to be $(p^3 - p)/3$. Now I do not see where I made the mistake, if anybody here can spot my mistake I would be very thankful.  Thank you in advance. :)

Determine the number of irreducible monic polynomials of degree 3 in $\mathbb F_p[x]$ where $p$ is a prime.  I'd like to start off by acknowledging that I know there are many posts relating to similar problems both on here and mathoverflow, however none address my problem.  In class, my professor went over the monic polynomials of degree 2 by reasoning that there are $p^2$ distinct polynomials, the reducible ones look like $(x - a)^2$ and $(x - a)(x - b)$ for the first one there are $p$ of them and for the second one there are $p(p-1)/2$ of them, subtracting the reducible ones from the total ones gives $$p^2 - p - \frac{p(p - 1)}{2} = \frac{2p^2 - 2p - p(p-1)}{2} = \frac{2p^2 - 2p - p^2 + p}{2} = \frac{p^2 - p}{2}.$$  I'm trying to use similar reasoning for polynomials of degree three using the fact that there are $p$ irreducible monic linear polynomials and $p(p-1)/2$ irreducible monic quadratic polynomials. But I can never get the result shown  and .  My reasoning is as follows: Observe that reducible polynomials would look like $(x - a)(x - b)(x - c)$, $(x - a)^2(x - b)$, $(x - c)^3$ and $(x^2 + ax + b)(x - c)$ formed from irreducible linear and quadratic monic polynomials.    For the first type where all three are distinct we can surmise that there are $p$ choices for the first, $p-1$ choices for the second and $p - 2$ choices for the third. So we have $p(p-1)(p-2)$. (is it $p$ choose $3$? Do I have to account for order not mattering?) For the second type there are $p$ choices for the square, and $p-1$ choices for the linear polynomial, so we have $p(p-1)/2$. For the third type, we have shown that there are $p(p-1)/2$ choices for the quadratic polynomials and there are $p$ choices for the linear polynomial. So we have $p^2(p-1)/2$.   Subtracting these values from $p^3$ should give me what I'm looking for, which is $p(p^2 - 1)/3$. But I'm not getting that.  Can someone tell me where my reasoning is wrong? Or tell me how to go about counting the number of irreducibles? (I know there are other methods of getting the answer, even more general ones, but I'm looking for a simple counting method that can help me better understand where my reasoning is wrong and help me correct it.)


I burned a copy of Ubuntu to dvd, I went to install it on an Acer Aspire 5610z which had vista. I removed vista and put xp on it about 3 or 4 years ago. My problem is that I now have a black screen with the following two lines of text at the top:  This kernel requires an x86-64 CPU, but only detected an i686 CPU. Unable to boot - please use a kernel appropriate for your CPU  My question is how and where do I find a version of Ubuntu that will work with my CPU?

I'm trying to install Lubuntu on my laptop (sorta old 2005). [Laptop stats: Intel® Celeron® CPU 410 @ 1.46 GHz 1.47GHz, 448 MB of RAM]  I press Install and this message appears:   This kernel requires an x86-64 CPU, but only detected an i686 CPU.  Unable to boot - please use a kernel appropriate for your CPU.   What can I do to install Lubuntu on my computer?


list.append(x)   Add an item to the end of the list.  Okay. Let's write some code:  x = [[]]*3 x[0].append('foo') print x   and output is:  [['foo'], ['foo'], ['foo']]   Why?

I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


I am receiving the following Error:  Unknown property 'AddExistingSpecsExt.Specifications__c' Line 0   VisualForce Code  <apex:page controller="AddExistingSpecsExt">     <apex:form>         <apex:pageblock title="Associate Specifications to Products">             <apex:pageMessages />             <apex:pageblockbuttons location="top">                 <apex:commandbutton value="Associate" action="{!associate}" />                 <apex:commandbutton value="Cancel" action="{!cancel}"/>             </apex:pageblockbuttons>             <apex:pageBlockSection>                 <apex:pageBlockSectionItem>                     <apex:outputLabel>Specification Name</apex:outputLabel>                     <apex:outputText>{!Specifications__c.Name}</apex:outputText>                    </apex:pageBlockSectionItem>               <apex:pageBlockSectionItem>                     <apex:outputLabel>Specifications</apex:outputLabel>                     <apex:inputField value="{!Specifications__r.Product__c}"/>                 </apex:pageBlockSectionItem>                             </apex:pageBlockSection>         </apex:pageblock>     </apex:form> </apex:page>   Controller  public with sharing class AddExistingSpecsExt {      public Specifications__c loadedSpec { get; private set; }  public AddExistingSpecsExt() {     String specId = ApexPages.currentPage().getParameters().get('id');     if (String.isBlank(specId)) return;      List<Specifications__c> candidates = [         SELECT Id, Name, Product__c FROM Specifications__c WHERE Id = :specId LIMIT 1     ];     if (!candidates.isEmpty()) loadedSpec = candidates[0]; }     public PageReference associate () {          Specifications__c candidates = new Specifications__c ( Id = loadedSpec.Product__c, Name =loadedSpec.Id);          try {             Database.update(candidates);         } catch (Exception error) {             ApexPages.addMessage(new ApexPages.Message(ApexPages.Severity.ERROR, 'Error while associating.' + error.getMessage()));         }          PageReference page = new PageReference('/' + candidates);          return page.setRedirect(true);     }      public PageReference cancel () {         PageReference page = new PageReference('/' + Null);         return page.setRedirect(true);             }  }

I am receiving apex errors with the following code:   public with sharing class AddExistingSpecsExt {      public Specifications__c loadedSpec { get; private set; }  public AddExistingSpecsExt() {     String specId = ApexPages.currentPage().getParameters().get('id');     if (String.isBlank(specId)) return;      List<Specifications__c> candidates = [         SELECT Id, Name, Product__c FROM Specifications__c WHERE Id = :specId LIMIT 1     ];     if (!candidates.isEmpty()) loadedSpec = candidates[0]; }     public PageReference associate () {          Specifications__c candidates = new Specifications__c ( Id = Specifications__c.Product__c, Name = Specifications__c.Id);          try {             Database.update(candidates);         } catch (Exception error) {             ApexPages.addMessage(new ApexPages.Message(ApexPages.Severity.ERROR, 'Error while associating.' + error.getMessage()));         }          PageReference page = new PageReference('/' + candidates);          return page.setRedirect(true);     }      public PageReference cancel () {         PageReference page = new PageReference('/' + Null);         return page.setRedirect(true);             }  }   Attempting to add records to a related list through a custom button and small vf page.   The Error is Line 16      Invalid initial expression type for field Specifications__c.Id, expecting: Id   Any help?


Could not initialize the package information An unresolvable problem occurred while initializing the package information. Please report this bug against the 'update-manager' package and include the following error message:  E:Encountered a section with no Package: header,  E:Problem with MergeList /var/lib/apt/lists/dl.google.com_linux_earth_deb_dists_stable_main_i18n_Translation-pt%5fBR,  E:As listas de pacotes ou o ficheiro de status não pôde ser analisado ou aberto.

The computer gave me this output in a window:  E: Encountered a section with no Package: header E: Problem with MergeList /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_natty_main_binary-i386_Packages E: The package lists or status file could not be parsed or opened.   How can I fix this?


The difinition of the Continuity is the following. $f(x)$ is continuous at a point $a$ means for every $\epsilon > 0$ , we will get a $\delta > 0$ such that $|f(x) - f(a) < \epsilon|$ for all $x$ satisfying $|x - a| < \delta .$ By using quantifiers , we can write $(\forall \epsilon > 0) (\exists \delta > 0 ) [ \forall x ( |x- a | < \delta \implies |f(x) - f(a) | < \epsilon )]$ The negation of the above statement will be '$( \exists \epsilon > 0) ( \forall \delta > 0 ) [\exists c (|c - a | < \delta \implies |f(c) - f(a)  | \geq \epsilon )]$ .' But I want to know how to do that using generalized De morgan's Law. Can anyone please help me?

How can we come to the statement where $f$ is discontinuous at point $x_{0}$, when we know epsilon-delta proof:  $\forall {\epsilon}> 0 \: \:  \exists \delta _{\epsilon}> 0 \; : \left | x-x_{0} \right |< \delta _{\epsilon} \Rightarrow \left | f\left ( x \right )-f\left ( x_{0} \right ) \right |< \epsilon $  I believe we should get something like this:  $\left | x-x_{0} \right |< \delta _{\epsilon} \Rightarrow \left | f\left ( x \right )-f\left ( x_{0} \right ) \right |f\geq  \epsilon $  but i don't know how to come to this point using logical operators.


I have been reading articles and watching space exploration documentaries,as astronauts stay on earth before launching into space,there's gravitational pull or force that acts upon them and the shuttle.  On the other side,after launching off into space and leaving the earth's gravitational waves;there's unknowingly certain energy or force that exists.  Therefore,I'm intrigued to know whether still gravitational waves/force acts again beyond the earth?  And if there's a force/energy that exists,what is the scientific term for it?

Well, this question has been puzzling me for kinda long time, many people believe that orbiting astronauts feel weightless because they are "beyond the pull of Earth's gravity"...How far from the Earth would a spacecraft have to travel to be truly beyond the Earth's gravitational influence? If a spacecraft were really unaffected by Earth's gravity would it remain n orbit? If so, what is the real reason for weightlessness in orbit?


If $f:I\subseteq \Bbb R \rightarrow \Bbb R$ is injective and everywhere continuous in its domain then $f^{-1}$ is also continuous everywhere. Here  $I$ cannot be discrete set and $f$ is single variable function The above statement is always correct or not? I thought it is always correct. Am I correct or not?


Is there a way to achieve a plasma effect as found in Halo? I want to create the blue plasma/flame effect not as an animation but just an image.

I need this for an animation. I tried using a smoke simulator, but the flames rise upwards and that's not what I was aiming for. I want the flames to maintain the vorticity but still stick close to the surface. Can anyone help me out here? Update: With the previous answer's help (along with a particle system) I was able to achieve this, however, i want the flames to have a more sharper look to it. Something more akin to the plasma bolt from 'Sorcerer's Apprentice'


I need to remove my Google  from Stack Exchange network, how can I do that ? I need only my facebook login and that Google login is associated with my previous company email id.

How do I remove login credentials (emails or OpenIDs) from my account?     For more information, see "" in the .


I'm planning a travel in the end of November and I want to pass through the Mont Blanc Tunnel, beginning in Chamonix until Aosta. In this epoch of the year is it common to snow up coming to the tunnel?

I am interested in hiking this fall in France and camping along the way. In order to figure what gear I need to pack to camp (particularly for the sleeping bag), I would like to know what temperatures to expect.  I am interested in historical temperatures to figure the usual temperature and I might look at them for other seasons. If that matters, I am thinking about hiking in the Pays Basque (South West of France), the mountainous part.  Where (ideally online and for free) can I find such data? Are there resources that cover Europe, or even the whole world?


I'm creating input field dynamically in my page with some id like #MyField And when I try to catch click event by $('#MyField').click(function (){}) it doesn't work! Am I do it in wrong way?

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


I have to switch between two terminals very often.  One terminal is a ssh-session to a local test-server and the other terminal is a ssh-session to a remote production server.  I am used to switching between windows with ALT-TAB.  Is there a way to make Ubuntu 18.04 switch between both with ALT-TAB?

Currently if I hold ALT + TAB and then while still holding down ALT I press TAB I am able to go between applications in a little view and then when I release all the keys that application and all its windows come to the front.  And this is very useful, but I would like to know if there is a way of switching between individual windows with this keyboard shortcut in the same way rather than grouping windows with an application to switch to?  I am running Ubuntu GNOME 15.10 with GNOME 3.18.


I just installed the latest Ubuntu 13.10 and I'm trying to figure out what drivers I should install and how to do it. I have an integrated Intel GPU and a Nvidia GeForce GT 650M that should work together according to the Optimus technology. The software updater doesn't show any additional third-party driver available, though, and this makes me think that maybe there are no drivers for Linux 3.11 yet. So the question is: do I have to install additional drivers over the ones preinstalled by the system? If yes, where can I find them?  Thank you and please forgive the mistakes I could have done, but I'm completely new to Linux and I'm trying to get started..

I recently made the switch to Ubuntu. Everything on my laptop works fine except my hybrid graphics card. It is Intel graphics combined with Nvidia GeForce GT650M. I tried Bumblebee, but primusrun doesn't work (segmentation fault, core dumped) and optirun works with glxspheres64, but steam games look worse with optirun than with Intel graphics (e.g. Surgeon Simulator 2013 runs fine with Intel and hangs a lot with optirun)   I tried Nvidia Prime, but it gives me a black screen on startup after install, so I can't do anything and have to power off my PC with the power button. I also tried nvidia-prime 0.5 on Ubuntu 14.04, and then I get 'low-graphics mode' and I can't get to Unity.


I am novice to T-SQL and want to achieve the following in SQL Server 2014:  My source table looks like this.  Col1      Col1       Col2       Col3 ------------------------------------ Group1    Val1       Val2       Val3.1 NULL      NULL       NULL       Val3.2 NULL      NULL       NULL       Val3.3 Group2    Val1.2     Value2.2   Val3.4   I want to concatenate based on the First 3 Cols which form a group but has null in the subsequent rows, and the last cols values differ which needs to be concatenated.  The desired result should be following two rows instead of 4:  Col1      Col1       Col2       Col3 ------------------------------------ Group1    Val1       Val2       Val3.1,Val3.2,Val3.3 Group2    Val1.2     Value2.2   Val3.4   If is it possible just to create a view or a select query that will do. Please help me as I could not figure this out with my knowledge.  This is not as simple as the other example found in StackOverflow:  ANDY   |  A100 ANDY   |  B391 ANDY   |  X010 TOM    |  A100 TOM    |  A510   My data is more like  ANDY   |  A100 NULL   |  B391 NULL   |  X010 TOM    |  A100 NULL    |  A510

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 :)


Let $(X,d)$ be a metric space, and let $0 < a < 1$. Define $d^a$ by $(d(x,y))^a$. Show that $d^a$ is a metric on $X$.  I was able to show everything except the triangle inequality. It's obvious that we can write $$(d(x,z))^a\le(d(x,y)+d(y,z))^a$$ but I'm not sure where to go from there. Any hints? Sorry about the annoying format; I'm new to this site.

If $0<\alpha < 1$ and $d(x,y)$ is metric, show that $((d(x,y))^{\alpha}$ is metric.   It remains for me to show that the triangle inequality, or $((d(x,y))^{\alpha}\leq ((d(x,z))^{\alpha}+((d(z,y))^{\alpha}$, holds.  I begin with the fact that $d(x,y)\leq d(x,z)+d(z,y)$. Then I apply the function:  $(d(x,y))^{\alpha}\leq (d(x,z)+d(z,y))^{\alpha}$  What now? I was thinking of expanding the right side but maybe it is not the best idea? I got a hint where if $a\geq 0, b\geq 0$ and $a+b=1$, then $a^{\alpha}+b^{\alpha}\geq 1$ but I don't really know how to apply this hint.


In my attempt to divide a title into two lines, I fail in inserting therein a “carriage return” (or \r, or \n), to effectuate a two-line title.  I must add code before this line:  resultHdr = resultHdr + “Title B”;   I need to change the “resultHdr” earlier; It must already contain “Title A” - and a “carriage-return”, so that the line of code above would yield Title A and, on a next line, Title B.  It would seem absurdly simple to accomplish. But neither of these additions succeeded for me:?  resultHdr = "Title A” + "\n”; resultHdr = “Title A \r”; resultHdr = “Title A \n”; resultHdr = resultHdr +  document.createElement('br');   I fail in breaking the output line into two; It always shows up as “Title ATitle B” - all on the same line!  The program involves DOM scripting and here may lie the reason for my “faulty” rendering.  (There's a lot of stuff written on this, like typing in \\n or replacing with regular expressions, but they are years old and obviously things ain't still all that cut and dry). (Meanwhile - I'm stuck!)

I'm currently adding verbose tooltips to our site, and I'd like (without having to resort to a whizz-bang jQuery plugin, I know there are many!) to use carriage returns to format the tooltip.  To add the tip I'm using the title attribute. I've looked around the usual sites and using the basic template of:  link with tip   I've tried replacing the ? with:
 &013; / &#13; \r\n Environment.NewLine (I'm using C#)   None of the above works. Is it possible?


First of all, I've been looking everywhere and I have not found a functional solution.  I need to display the points from a data file exported from Qgis.  I tried Qgis2web, but I'd like to put everything up in the Leaflet from the beginning and then just update the data from Qgis.  Explorer does not report any errors, but it does not show points with markers.  Here is index:   <!doctype html>             <meta charset="utf-8">         <meta http-equiv="X-UA-Compatible" content="IE=edge">         <meta name="viewport" content="initial-scale=1,user-scalable=no,maximum-scale=1,width=device-width">         <meta name="mobile-web-app-capable" content="yes">         <meta name="apple-mobile-web-app-capable" content="yes">         <title>PinLeX</title>                           <link rel="stylesheet" href="css/leaflet.css" />

       And here map set (leafletmap.js):  var map;    function initmap() {     // set up the map     map = new L.Map('map');      // create the tile layer with correct attribution     var osmUrl='http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png';     var osmAttrib='Map data © OpenStreetMap contributors';     var osm = new L.TileLayer(osmUrl, {   minZoom: 8,    maxZoom: 18,    attribution: osmAttrib   })          // start the map in defined location     map.setView(new L.LatLng(48.974244, 14.478729),9);     map.addLayer(osm);    // PinLayer   var pinpoint = L.icon({   iconUrl: 'markers/pinpoint.svg',   iconSize: [26.599999999999998, 26.599999999999998],   iconAnchor: [16, 37],   popupAnchor: [0, -28]   });    L.geoJson(PinLayer, {   pointToLayer: function (feature, latlng) {             return L.marker(latlng, {icon: pinpoint});     },   }).addTo(map); }   And here GeoJson (transformed to js - PinLayer.js)  var PinLayer = { "type": "FeatureCollection", "name": "PinLayer", "crs": { "type": "name", "properties": { "name": "urn:ogc:def:crs:EPSG::3857" } }, "features": [ { "type": "Feature", "properties": { "id": null, "name": "Senovážné náměstí", "country": "Česká republika", "desc": "Popis není k dispozici.", "status": "v provozu", "photocell": "ne", "admin": "Statutární město České Budějovice (?)", "update": "7\/4\/2018", "spec": "České Budějovice", "type": "standartní pítko", "photo": null }, "geometry": { "type": "Point", "coordinates": [ 1611753.67562, 6270485.80685 ] } }, { "type": "Feature", "properties": { "id": null, "name": "Katedrála sv. Mikuláše", "country": "Česká republika", "desc": "Popis není k dispozici.", "status": "v provozu", "photocell": "ne", "admin": "Statutární město České Budějovice (?)", "update": "12\/4\/2018", "spec": "České Budějovice", "type": "standartní pítko", "photo": null }, "geometry": { "type": "Point", "coordinates": [ 1611428.44996, 6270639.98718 ] } } ] }

I am trying to get a GeoJSON with projected coordinates to show in Leaflet.  I have no problems loading GeoJSON with lat/lng (EPSG:4326). Here is a  where I load the GeoJSON with unprojected lat/lng.  I am using the Leaflet 1.0.0-beta.2 (954e83d) in the fiddle but I am happy to use another version.  I am aware of the coordsToLatLng method of L.geoJson but no idea how to make this work.  This is the GeoJSON with the projected (EPSG:3857) coordinates.  {     "type": "FeatureCollection",     "crs": {         "type": "name",         "properties": {             "name": "urn:ogc:def:crs:EPSG::3857"         }     },     "features": [{         "type": "Feature",         "properties": {          },         "geometry": {             "type": "Polygon",             "coordinates": [[             [-625570.6, 6465993.0],             [-305006.9, 6696510.8],             [-546330.2, 6768547.6],             [-445478.6, 7053093.0],             [-279794.0, 7056694.8],             [-359034.5, 7337638.4],             [-211359.0, 7485313.8],             [62380.8,   6955843.3],             [220861.7,  6909019.4],             [91195.5,   6700112.6],             [213658.1,  6682103.4],             [-625570.6, 6465993.0]]]         }     }] }     Notes: I am new to Leaflet. I come from a GIS background. I have a very good understanding of projections and transformations. I have a very good understanding of OpenLayers3. I use OL3 to do things such as this on a daily basis. The data in this post is obviously just an example. I am trying to learn Leaflet in order to compare the performance with OL3. I know how to use QGIS and can unproject the data manually but this is not the point of this post.  This is not a repost. I have checked every bit of information on coordsToLatLng but didn't find any good documentation and nothing like a working example. Certainly no fiddle.  Just saying this as I have read a lot of Leaflet posts on gis.stackexchange with half-a-code. And a lot of answers which suggest to change the data. I know that Leaflet is not a GIS system and the makers are not from a GIS background. In the last hour I have just read a lot of rubbish about Leaflet using EPSG:3857 as default SRS and WGS84 being an SRS.


So I tried rebooting my pc recently and now it won't let me log in. It just kicks me back to log in screen  I've tried rm./home/*/.xauthorith Cannot remove is a directory  And a few of the other more common ones like purging nvidia. Just said the was no nvidia to purge

My Ubuntu is stuck in a login loop when trying to enter my desktop. When I login, the screen gets black and soon after that the login screen comes back.   I've read that the problem might be caused by an error depending on the graphics, here's my graphics card: ATI Radeon 7670M


When I go to the rendered view, the object is very hard to see and I cant put any textures s on it.  and here is a rendered image of it  It's a .png file and the white surface should a plane, but there are no textures. This error corrupted every blender, including the already created ones. What should I do?

I don't know why but now, when i go in material preview or rendered (in solid mode it works fine), my object is entirely gray, or invisible idk, because it has the same color of the background. I've been working for days on this project without having this issue, it suddenly showed up. I tried opening other old projects and suddenly they all do the same so i guess it is some blender program setting that applies for all the projects, but idk how it happened cuz i didn't change anything :/, anyone got any tips?


I am making a 2D java game based on Space Invaders. In my Game class I have these 3 fields:  //enemies left to kill private LinkedList<Enemy> enemiesLeft = new LinkedList<Enemy>();  //enemies killed private LinkedList<Enemy> enemiesKilled = new LinkedList<Enemy>(); //missiles that have been fired private LinkedList<Missile> missiles = new LinkedList<Missile>();   In my checkCollision() method I run through each Enemy in the enemiesLeft list and check for collision with each Missile in the missiles list, but it throws a ConcurrentModificationException.  Here is the checkCollision() method:  private void checkCollisions(){   //make an iterator over enemies   ListIterator<Enemy> iterEnemies = enemiesLeft.listIterator();       //loop through enemies   while(iterEnemies.hasNext()){     //error is thrown at below line     Enemy e = iterEnemies.next();  //current Enemy      //go through each Missile     ListIterator<Missile> iterMissiles = missiles.listIterator();      while(iterMissiles.hasNext()){       Missile m = iterMissiles.next();  //current Missile       if(e.doesIntersect(m)){                  //remove Enemy from enemiesLeft and add it to enemiesKilled list       enemiesKilled.add(enemiesLeft.remove(enemiesLeft.indexOf(e)));       //remove Missile       missiles.remove(m);       }     }   }    updateScore(); }   And this is the error I get:  java.util.ConcurrentModificationException    at java.util.LinkedList$ListItr.checkForComodification(Unknown Source)    at java.util.LinkedList$ListItr.next(Unknown Source)    at Game.checkCollisions(Game.java:168)    at Game.run(Game.java:197)    at Game.main(Game.java:279)    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)    at java.lang.reflect.Method.invoke(Unknown Source)    at      edu.rice.cs.drjava.model.compiler.JavacCompiler.runCommand(JavacCompiler.java:272)   The game runs smooth until a collision occurs. Please help me!

We all know you can't do the following because of ConcurrentModificationException:  for (Object i : l) {     if (condition(i)) {         l.remove(i);     } }   But this apparently works sometimes, but not always. Here's some specific code:  public static void main(String[] args) {     Collection<Integer> l = new ArrayList<>();      for (int i = 0; i < 10; ++i) {         l.add(4);         l.add(5);         l.add(6);     }      for (int i : l) {         if (i == 5) {             l.remove(i);         }     }      System.out.println(l); }   This, of course, results in:  Exception in thread "main" java.util.ConcurrentModificationException   Even though multiple threads aren't doing it. Anyway.  What's the best solution to this problem? How can I remove an item from the collection in a loop without throwing this exception?  I'm also using an arbitrary Collection here, not necessarily an ArrayList, so you can't rely on get.


how to make an bright spot similar to a star ?  i  we tried to make a sphere and add emission to it but it didn't work it only made the sphere clear bright without looking like a star  you know something similar to this image right here

I'm kinda new to Blender. Currently playing around with version 2.8 to practice some rendering. Is there a way to achieve this 'light-star' effect for the blooming objects with the emission? If there is an alternative way then it's fine too. See these images below for references. Thanks in advance:


In the , on page 24, we can find the following plot:  Question: What is the dashed line really representing? After all, it says in the caption that this line represents "the background-only expectations". But why do I expect for background $\frac{\sigma}{\sigma_{\text{SM}}}\ne 1$!? To me, background means SM background, and hence $\frac{\sigma}{\sigma_{\text{SM}}}\ne 1$ should be $1$, not?

On the following Higgs $\rightarrow$ Tau Tau plot, since we are plotting the ratio of $\frac{\sigma}{\sigma_{SM}}$ on the y axis, shouldn't the expected for this be 1? i.e., shouldn't the expected 68% and 95% be centered at a dotted line at 1? Anything else seems to imply we are expecting something other than the Standard Model...


I have in file /tmp/users list of users ( each list contain diff users )  Example  more /tmp/users   root kafka yarn hdfs root root yarn moon apache start moon apache   I want to print the users that appears in the file /tmp/users and count them as the following  Expected results  apache - 2 Hdfs - 1 Kafka - 1 Moon - 2 Root - 3 Start - 1 Yarn - 2

I have Apache logfile, access.log, how to count number of line occurrence in that file? for example the result of cut -f 7 -d ' ' | cut -d '?' -f 1 | tr '[:upper:]' '[:lower:]' is  a.php b.php a.php c.php d.php b.php a.php   the result that I want is:  3 a.php 2 b.php 1 d.php # order doesn't matter 1 c.php


I'm currently refactoring/tidying up some old C code used in a C++ project, and regularly see functions such as:  int f(void)   which I would tend to write as:  int f()   Is there any reason not to replace (void) with () throughout the codebase in order to improve consistency, or is there a subtle difference between the two that I am unaware of?  More specifically, if a virtual member function in C++ is described as:  virtual int f(void)   and a derived class includes a member function:  int f()   is this a valid override?  Additionally, am I likely to encounter any linker problems based on almost identical signatures?

Consider these two function definitions:  void foo() { }  void foo(void) { }   Is there any difference between these two? If not, why is the void argument there? Aesthetic reasons?


I searched through a lot of forums and googled in general, but I just can't find the answer. So I will ask here, and am a hopeful of a solution from you folks.  New to Linux and all that, but pretty familiar with computers.  Installed 12.10 on an old Dell Dimension 3000 Desktop. Installation was slow but  completed without problems.  After reading around a bit, I am nearly positive that this must have something to do with the video drivers, but again, I have not seen anyone with exactly similar nature to my situation that has a valid solution.  After logging in, I am left with the wallpaper and a functioning cursor- nothing more. I am able to open a terminal with the hotkey ctrl+alt+t, and able to exit the GUI straight to command interface with ctrl+alt+f1.  Even after multiple updates, downloads, installs and even reinstallation, I am stuck. Anyone able to shed some light? Please ask for any necessary specifications.

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


I have a custom label : My_Label which stores a string like Error1,Error2,Error3. In my workflow rule I have to check if Custom field F1__c contains any of the error specified in My_Label then fire the email alert. How can I check in my workflow **if custom field F1__c contains any of the error string present in Custom Label?  Is it possible to achieve without creating multiple Custom Labels?

I have a picklist field-XYZ which contains a lot of values.Lets say (A,b,c,d...z) I am trying to write a rule criteria which will execute if the picklist value is any of the following (A,b,c...p).So instead of mentioning all the values in rule criteria , i created a custom label and put the values (a,b,c,d..p) in that and wrote the following in the rule criteria :   CONTAINS(TEXT(XYZ__c) ,$Label.CustomLabel))   This is not working even is the value of the picklist is equal to the one mentioned in the Custom Label.I guess the CONTAINS function is matching the whole value of custom label with Picklist.Is there other workaround/solution for this?


If there is another answered question here which addresses my question kindly point it out to me and I'll gladly delete this.  I am an American who is visiting the UK. I am scheduled to travel by bus to Dublin and then fly from Dublin to Athens in the Schengen zone. I gather most of the time there are no immigration checks when doing this by bus and hence ones entry may not be recorded.  I know that Americans do not need a visa to visit Republic of Ireland, however do I have to go to a border post to get my passport stamped? For example although Americans do not require a visa to travel to the UK, they need to go through immigration controls and be granted leave to enter. Is it the same for Ireland, or my leave to enter UK automatically equates leave to enter Ireland?  My exit from Ireland is by air so it will be captured so they will know I was there. Won't there be trouble at the airport when exit controls realize they do not have my proof of entry?

With the Common Travel Area forming a partially open-border zone, what should a non-EU/Schengen citizen travelling within it keep in mind?  For example, do passports get checked, and perhaps stamped, at internal CTA borders?


I am planning to travel from Sweden to Spain by plane. I lost my ID and waiting for replacement but I do not want to go over the hassle when boarding the plane. Would I need to show ID card knowing that I will be booking online? I believe if I book online and travelling to another Schengen country, I would not need to show ID and only the boarding ticket?

A friend recently got her ID stolen while she was in the Netherlands. She will soon need to fly to her home country Italy, but she doesn't know what to do.  What can one do in such a situation? As far as I know, since it's Schengen, you don't need an ID card to go through borders. On the other hand, this is air travel, so they always require it for security reasons.   Can she show another document that proves her nationality? A copy of the ID card? Anything?


I was considering the energy and work done on an object experiencing uniform circular motion in a vertical plane, eg. a ball on a string swung vertically, and I arrived upon these conclusions:   The kinetic energy must be constant as $K=0.5mv^2$ and since the object is moving in UNIFORM circular motion the magnitude of the velocity is constant. The gravitational potential energy, $U$ must change as the object varies in height   Though, as this is a closed system, the mechanical energy (sum of $K$ and $U$) must be conserved - however, this does not seem to be the case as the $U$ varies whilst $K$ is constant.   Does this imply that an external force has been applied to the system? How else can you account for this discrepancy?

This is the picture in my mind:    For centripetal force, I learned that: $T-mg\cos\theta= \frac{mv^2}{r}$  In vertical circular motion, the velocity is naturally going to decrease as kinetic energy is converted to potential energy as the particle moves up the circle- and thus resulting into a non-uniform circular motion.  However, I was told that if tension changes accordingly, the velocity will remain constant(as from the equation). What I do not get about this part of the explanation is that which force will balance mgsinθ (tangential force in the diagram  )?


Let $X \subseteq \mathbb{R}^d$. We want to show that $X$ is closed iff every Cauchy sequence in $X$ converges in $X$.  MY attempt:  Let $X$ be a closed set, and pick a convergent sequence $(x_n)$ in $X$. Since $X$ is closed, then we know that $x_n \to x \in X$. Since convergence implies Cauchy, then we have found that every Cauchy sequence in $X$ is convergent, as desired.  Conversely, suppose every Cauchy sequence converges in $X$, we want to show that $X$ is closed. To this end, pick a sequence $(x_n) \subseteq X$ such that $x_n \to L$. We want to show that $L \in X$. Since $(x_n)$ converges, then it must be Cauchy. And by hypothesis, then we must havethat $L \in X$.  Is this correct? thanks for any feedback in advanced.

Here's my proof in my own words, does it stack up?   Showing $A$ is complete implies $A$ is closed. Let $(x_n)$ be a convergent sequence in $A$. $A$ is complete $\implies (x_n) \to p \in A$. Hence $A$ is closed. Showing $A$ is closed $\implies$ $A$ is complete. Let $(x_n)$ be a convergent sequence in $A$. $A$ is closed $\implies (x_n) \to p \in A$. As every convergent sequence is a Cauchy sequence, $(x_n)$ is a Cauchy sequence in $A$ that converges to $p \in A$ and hence $A$ is complete.   That sound ok?  As an aside, it seems to me that the definition of completeness and closed are basically identical, why are there two definitions for the same thing? Am I missing something here?


I have a file that contains a list of dates in MM/DD/YYY format. Each of these is stored in a $date_variable inside a while loop. I also have:  current_date="$( date +%x )"  I need to compare the dates from the file to the $current_date.   How can I say "if current date = $date_variable + at least 7 days? or "if at least 7 days have passed since $date_variable, then do this".  I have tried working with "if" comparison operators, but I don't get the expected result because of the format of $date_variable.  Also, I find it hard to change the format of $date_variable because they are being taken from a webpage with curl and grep.  EDIT:  My script looks like this:  # Store current date in the MM/DD/YYYY format current_date="$( date +%x )"  # Iterate each line from hotfix_final and read the variables hf_link and release_date while read -r hf_link release_date; do    # Install hotfixes on POC machines   if [ "$current_date" > "$release_date" ]; then     wget "$hf_link"   fi  done </home/abc/hotfix_final # Set the file as input for the whole while loop   hotfix_final:  https://download.abc.com/hotfix 06/24/2019 https://download.abc.com/hotfix2 06/26/2019   and I'd like to say:  if "$current_date" = "$release_date" + at least 7 days; then ...; fi

I need to do date arithmetic in Unix shell scripts that I use to control the execution of third party programs.   I'm using a function to increment a day and another to decrement:   IncrementaDia(){ echo $1 | awk ' BEGIN {         diasDelMes[1] = 31         diasDelMes[2] = 28         diasDelMes[3] = 31         diasDelMes[4] = 30         diasDelMes[5] = 31         diasDelMes[6] = 30         diasDelMes[7] = 31         diasDelMes[8] = 31         diasDelMes[9] = 30         diasDelMes[10] = 31         diasDelMes[11] = 30         diasDelMes[12] = 31 } {         anio=substr($1,1,4)         mes=substr($1,5,2)         dia=substr($1,7,2)          if((anio % 4 == 0 && anio % 100 != 0) || anio % 400 == 0)         {                 diasDelMes[2] = 29;         }          if( dia == diasDelMes[int(mes)] ) {                 if( int(mes) == 12 ) {                         anio = anio + 1                         mes = 1                         dia = 1                 } else {                         mes = mes + 1                         dia = 1                 }         } else {                 dia = dia + 1         } } END {         printf("%04d%02d%02d", anio, mes, dia) } ' }  if [ $# -eq 1 ]; then         tomorrow=$1 else         today=$(date +"%Y%m%d")         tomorrow=$(IncrementaDia $hoy) fi   but now I need to do more complex arithmetic.   What it's the best and more compatible way to do this?


I have an object which would translate into a Dictionary in C# and I'm trying to loop through all my "keys" so that I can draw my objects in order.  Let's say that this dictionary contains three objects with the keys 1, 2 and 3.  for (var key in myDictionary) {     if (key === "indexOf" || key === "length")         continue;     // Do stuff... }   Now, in IE9+, Chrome and Firefox, the output will be 1, 2, 3 while in IE8 the output is 2, 1, 3. As it is crucial for my application that these objects are given in order you can understand that this is unwanted behavior.  My question, therefore, is: Why does this happen and is there a known workaround that fixes my issue?

Does the "for…in" loop in Javascript loop through the hashtables/elements in the order they are declared? Is there a browser which doesn't do it in order? The object I wish to use will be declared once and will never be modified.  Suppose I have:  var myObject = { A: "Hello", B: "World" };   And I further use them in:  for (var item in myObject) alert(item + " : " + myObject[item]);   Can I expect 'A : "Hello"' to always come before 'B : "World"' in most decent browsers?


I am close to finishing a degree in a combined program in computer science and physics, and I am thinking of applying to graduate school in environmental modelling, ideally with a strong mathematical and computational focus.  My overall GPA seems to be respectable, 3.72 (if I'm doing the conversion correctly). However, I have done much better in computer science courses (3.96) and worse in math (3.51) and physics (3.58).  The problem is that many of the grad programs I'm interested in are in math departments, and I fear that the low math GPA will exclude me from top programs. I should note that part of the reason for the math marks is that I took mostly honours courses, but I worry that admissions committees will not be able to tell (the course names don't always indicate this). I have, however, taken several courses in mathematical methods (both under computer science and math departments) and done very well, and am also taking a math-heavy graduate course in machine learning.  I have extended my degree by a semester to do a math minor, but unfortunately most of my marks for this will not be out by the time I apply for grad programs. I plan to study quite a bit for the GRE Math Subject Exam.  I have research experience in mathematical biology as well as currently working on an undergraduate thesis in environmental modelling. I will hopefully have one or two publications related to this research by the time I apply for schools.  How can I tailor my applications to have a good chance of getting into applied math programs? Will they care about my strong computer science marks, or my marks in specific courses? Should I try instead for computer science programs and go from there?

When applying to a PhD program in the US, how does the admissions process work? If an applicant is weak in a particular area, is it possible to offset that by being strong in a different area?  Note that this question originated from this . Please feel free to edit the question to improve it.


The question is simple, to prove that  $\sum_{n=1}^\infty{\frac{2}{2n}-\frac{2}{2n+1}}=2-2\ln(2)$. I did it by wirtting down some terms of the series, rearranging as follows: $$\sum_{n=1}^\infty \frac{2}{2n}-\frac{2}{2n+1}$$ $$2\sum_{n=1}^\infty \frac{1}{2n}-\frac{1}{2n+1}$$ $$2\left[\frac 12 - \frac 13 + \frac 14 - \frac 15+ \frac 16- \frac 17+ \frac 18- \frac 19+ \ldots\right]$$ $$2\left[1-\left(1-\frac 12 + \frac 13 -\frac 14 +\frac 15-\frac 16+\frac 17-\frac 18+\frac 19-\ldots\right)\right]$$ and noticing that the series inside the round parenthesis corresponds to $$1-\frac 12 + \frac 13 -\frac 14 +\frac 15-\frac 16+\frac 17-\frac 18+\frac 19-\ldots=\ln(2)$$ follows that: $$2[1-\ln(2)]=2-2\ln(2)$$ So what I'm wanting to clarify is if is there any other way to improve this answer, a more "elegant" way to come up to the infinite sum of the series.

I came across the following statements $$\sum_{n=1}^{\infty} \frac{1}{n(2 n+1)}=2-2\ln 2 \qquad \tag{1}$$ $$\sum_{n=1}^{\infty} \frac{1}{n(3 n+1)}=3-\frac{3 \ln 3}{2}-\frac{\pi}{2 \sqrt{3}} \qquad \tag{2}$$ $$\sum_{n=1}^{\infty} \frac{1}{n(4 n+1)}=4-\frac{\pi}{2}-3 \ln 2 \qquad \tag{3}$$ $$\sum_{n=1}^{\infty} \frac{1}{n(6 n+1)}=6-\frac{\sqrt{3} \pi}{2}-\frac{3 \ln 3}{2}-2 \ln 2 \qquad \tag{3}$$ The (1) by partial fractions $$\sum_{n=1}^{\infty}\frac{1}{n(2n+1)}=\sum_{n=1}^{\infty}\frac{1}{n}-\frac{2}{2n+1}$$ $$=\sum_{n=1}^{\infty}\frac{1}{n}-\frac{1}{n+\frac{1}{2}}$$ Recall the Digamma function $$\psi(x+1)=\gamma+\sum_{n=1}^{\infty}\frac{1}{n}-\frac{1}{n+x}$$ Therefore $$\sum_{n=1}^{\infty}\frac{1}{n}-\frac{1}{n+\frac{1}{2}}=\psi(1+\frac{1}{2})-\gamma$$ $$\sum_{n=1}^{\infty}\frac{1}{n(2n+1)}=\psi\left(\frac{3}{2}\right)-\gamma$$ In the same token we can derive the relation for the other three ralations. My Question is: can we calculate the values of the digamma function for those values without resorting in the Gauss´s Digamma formula? $$\psi\left(\frac{r}{m}\right)=-\gamma-\ln (2 m)-\frac{\pi}{2} \cot \left(\frac{r \pi}{m}\right)+2 \sum_{n=1}^{\left\lfloor\frac{m-1}{2}\right\rfloor} \cos \left(\frac{2 \pi n r}{m}\right) \ln \sin \left(\frac{\pi n}{m}\right)$$  I tried this approach also, but I think the resulting integral is divergent $$\sum_{n=1}^{\infty} \frac{1}{n(2 n+1)}=\sum_{n=1}^{\infty} \frac{1}{n}\int_{0}^{1}x^{2n}dx=\int_{0}^{1}\sum_{n=1}^{\infty} \frac{x^{2n}}{n}=-\int_{0}^{1}\ln(1-x^2)dx $$


There are some classical quantities, for which we know corresponding operators: e.g. position, momentum. For some others it's straightforward to compose these operators using expressions similar to their classical counterparts, e.g.  $$\vec L=\vec r\times\vec p\;\leadsto\; \hat{\vec L}=\hat{\vec r}\times\hat{\vec p}.$$  After checking that the resulting operator is Hermitian, we can use it as the operator for our quantity.  But in some cases we have to do some special considerations. E.g. one term of the Laplace-Runge-Lenz vector in classical mechanics, whose operator cannot be straightforwardly composed from simpler operators:  $$\vec p\times\vec L\;\not\leadsto\;\hat{\vec p}\times\hat{\vec L},$$  because such an operator wouldn't be Hermitian. Fortunately, we can easily form an appropriate Hermitian version of it by adding a symmetrizing term, so that the expression is equivalent to the original classically, but results in an Hermitian operator:  $$\vec p\times\vec L\;\leadsto\;\frac12\left(\hat{\vec p}\times\hat{\vec L}-\hat{\vec L}\times\hat{\vec p}\right).$$  But is there always a unique choice of an Hermitian combination of operators which would reduce to a given classical expression of corresponding observables? If not, what are some examples where one classical expression could be represented by more than one different Hermitian operators? Do we have any criteria of choosing one over others without need to do experiment?

I have been told that $$[\hat x^2,\hat p^2]=2i\hbar (\hat x\hat p+\hat p\hat x)$$ illustrates operator ordering ambiguity.  What does that mean? I tried googling but to no avail.


Let $G$ be the group of all $2\times 2$ matrices  \begin{bmatrix}a&b\\c&d\end{bmatrix} where $a,b,c,d$ are integers modulo $p$ for $p$ prime such that $ad-bc\not =0$.$G$ forms a group relative to multiplication. Then how do I find the order of $G$?  I really don't know how to proceed. All I could try is look at $p=3$. So, I tried to count the number of solutions to $ad-bc=0 \bmod p$ manually by squaring and adding the number of solutions to $ad=0 \bmod p$, $ad=1 \bmod p$, $ad=2 \bmod p$.Let that sum be $k$. Then the order of $G$ is $3^4-k=81-k$.  The same method however does not work with a general prime $p$. Would someone give me a hint to solve this problem? Thanks.

From problem 2.3.25 in Topics in Algebra, 2$\varepsilon$ by I. N. Herstein:     Let $G$ be the group of all $2 \times 2$ matrices $\left(\begin{array}{c c}a & b \\ c & d\end{array}\right)$ where $ad-bc \ne 0$ and $a,b,c,d$ are integers modulo 3, relative to matrix multiplication. Show that $o(G) = 48$.   I know that $o(G) \le 3^4 = 81$, since $a,b,c,d$ can each take one of 3 values (mod 3). I attempted to tighten this bound by finding the number of matrices such that $ad=bc$ (mod 3):   Suppose $ad=bc=0$ (mod 3). Then ($a = 0$ or $d = 0$) and ($b = 0$ or $c = 0$), leading to 36 possible values for $(a,b,c,d)$. Suppose $ad=bc=1$ (mod 3). Then ($a=d=1$ or $a=d=2$) and ($b=c=1$ or $b=c=2$), leading to 4 possible values for $(a,b,c,d)$. Suppose $ad=bc=2$ (mod 3). Then ($(a,d)=(1,2)$ or $(a,d)=(2,1)$) and ($(b,c)=(1,2)$ or $(b,c)=(2,1)$), leading to 4 possible values for $(a,b,c,d)$.   So, there are in total $36+4+4 = 44$ such $\left(\begin{array}{c c}a & b \\ c & d\end{array}\right)$ where $ad-bc=0$ (mod 3). That means there are at most $81-44 = 37$ such $\left(\begin{array}{c c}a & b \\ c & d\end{array}\right)$ where $ad-bc\ne 0$, i.e., $o(G) \le 37$. However, this contradicts the problem. Where did I go wrong? Can someone set me on the right path?


Recently, I have random occurence where I can't reach my server. When this occurs, about 1 ping on each 10 manage to ping back. The ping that do get through are within normal response time (about 42ms in my case).  The only information I could gather so far is my network usage graph. When those timeouts occur, my server recieves unusually HIGH traffic from the internet.   (today graph)  (this week graph)  If this may help, my server is supposed to be under a 100 mbits internet connection.  Am I right to think those spikes are related to my ping's timeout? Also, do anyone have any idea of what this traffic might be? It started about a week ago, nothing has drastically changed in my infrastructure for over a year.  Thank you for your help.

This is a  about DoS and DDoS mitigation.   I found a massive traffic spike on a website that I host today; I am getting thousands of connections a second and I see I'm using all 100Mbps of my available bandwidth.  Nobody can access my site because all the requests time out, and I can't even log into the server because SSH times out too!  This has happened a couple times before, and each time it's lasted a couple hours and gone away on its own.  Occasionally, my website has another distinct but related problem: my server's load average (which is usually around .25) rockets up to 20 or more and nobody can access my site just the same as the other case.  It also goes away after a few hours.  Restarting my server doesn't help; what can I do to make my site accessible again, and what is happening?  Relatedly, I found once that for a day or two, every time I started my service, it got a connection from a particular IP address and then crashed.  As soon as I started it up again, this happened again and it crashed again.  How is that similar, and what can I do about it?


Please explain why $10$ raised to the power of $0$ i.e., $10^0$ is equal to $1$ and $10^1$ is simply equal to $10$, then the numbers between $1$ and $10$ can be written as $10$ raised to some power between $0$ and $1$.

I have been a witness to many a discussion about numbers to the power of zero, but I have never really been sold on any claims or explanations.  This is a three part question, the parts are as follows...    1) Why does $n^{0}=1$ when $n\neq 0$?  How does that get defined?  2) What is $0^{0}$?  Is it undefined?  If so, why does it not equal 1?  3) What is the equation that defines exponents?  I can easily write a small program to do it (see below), but what about in equation format?    I just want a little discussion about numbers to the power of zero, for some clarification.    Code for Exponents: (pseudo-code/Ruby)  def int find_exp (int x, int n){     int total = 1;     n.times{total*=x}     return total; }


I'm gonna travel from Stockholm to Rome via British airways but have long layover in London Heathrow.  My question is:   Do I need transit visa to go outside airport and just explore city? if I do require visa can I get that visa on arrival to UK on the airport from British border control officer?

Is there a website or some other way to find out if I need a transit visa for a short stop in the UK on my way somewhere else? Ideally this should give me the answer for all nationalities, and take into account any other visas I may have.


I'm currently learning C and I am struggling on the concept of pointers. I want to calculate the size of a char array within the respective function to limit the amount of parameters needed: char palindrome(const char str[], int count);  int main() {     char input[] = "anna";     int size = sizeof(input) / sizeof(input[0]); // size = 5      palindrome(input, size);      return EXIT_SUCCESS; }  char palindrome(const char str[], int count) {     int size = sizeof(str) / sizeof(str[0]); // size = 1?      code...      return EXIT_SUCCESS; }  If anyone can explain why the value of size differs I would really appreciate it as I think the way I use '&' and '*' is partly incorrect.  for example a pointer would refer to the address of where the variable is stored (i.e. any variable change using asterisks would globally change x's value?). I don't understand the difference of declaring a variable compared to a pointer I think is the issue. Many thanks, Callum

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


Working from home during lockdown, I seem to need to use the Linux version of some proprietary software (Bruker OPUS). It's the only software that will read the proprietary file format. I don't have a Windows machine or an off-site licence, but the Linux binaries are a free download. The software was last updated nearly 10 years ago and  apparently doesn't run under 12.04 or later.  I've installed Lucid in a virtual machine.  While I can't get the guest extensions to install I can make ISOs to transfer stuff onto it. However OPUS needs libboost and probably other things (this seems to be one of several reasons it won't install on a newer OS) and the repository for Lucid no longer exists on archive.ubuntu.com/ubuntu/dists/.  So how can I satisfy dependencies for an OS so old the repositories aren't there any more?

Recently I have installed an older version of Ubuntu on my old machine. Whenever I try to install any software, I get an error saying it couldn't be found:  $ sudo apt-get install vlc Reading package lists... Done                Building dependency tree        Reading state information... Done     E: Couldn't find package vlc


I have got my BS and master both with honor with good GPAs. But Now I want to know which of these have more importance to US PhD program in Computer engineering. TOEFL and GRE  or publication records. What I am looking for is some case like this:   T : 107   G : x   p : 0 T : 98    G : x   p : 1   which case has more chance ?

When applying to a PhD program in the US, how does the admissions process work? If an applicant is weak in a particular area, is it possible to offset that by being strong in a different area?  Note that this question originated from this . Please feel free to edit the question to improve it.


I have had problems with converting strings (like inputs) into denary, as a string is a necessary for using hexadecimal (as it can't be stored as an integer because of the characters a-f being included). Here are two attempts that don't work: >>> hex_number = 'ff' #(255 in denary) >>> ascii(0xhex_number) SyntaxError: invalid hexadecimal literal >>> ascii('0x'+hex_number) "'0xff'"  I have also seen that you can use format() somehow, but that didn't work either. >>> format(hex_number, '16') #This was what the demo said to do. 'ff              '  How can I get it so that hex_number (hexadecimal) is converted to denary (aka decimal), or any other n-base number systems?

How do I convert a hex string to an int in Python?   I may have it as "0xffff" or just "ffff".


Drupal always change permissions of /sites/default and settings.php. Now I move it in my VPS and maybe I misconfigure user www-data access but i cannot remember what exactly.  Now Drupal does not change permissions.  This problem caused by my mistakes.  Please, how to return proper configuration to have a Drupal works fine?

I'm gearing up to deploy a Drupal 7 site and I can't find any documentation about what the recommended security-conscious file and directory permissions should be set to.  Specifically default/files/ (also sub directories?), settings.php, .htaccess and anything else I should be aware of.


I apologize if this has already been suggested elsewhere; I did a cursory search that did not return any results. At the least, it looks like this suggestion does not have it's own question on Meta.  There has been quite a bit of buzz regarding the Hot Network Questions (HNQs), and what should and should not be included.   I would suggest that, regardless of what is decided, the HNQs should be customizable. Of course, there should be a default list / behavior of what is included in the HNQs, which would be used from anonymous users and by default.   This default list may exclude certain sites, for various reasons. This question isn't meant to discuss the merits of this, but to point out that the pain of these decisions on certain users (some users will be upset if a site is excluded, others will be upset if a site is included) may be alleviated by allowing users to customize which sites show up in the HNQs.  For example, (I believe) many of the language sites are excluded from the HNQs by default, as the questions are not relevant to most users. Well, if I speak Chinese, it would be great to include that site in my HNQs. Or, if I am only interested in StackExchange for programming / technical questions, I may wish to limit my list to only those sites.  I know this feature would come at a "cost", of reducing StackExchange's ability to advertise certain sites to certain users (the whole point of the HNQs!). However, if a user deselects a site from their HNQs, it's likely they aren't interested in the site and wouldn't visit it anyways. I would also argue they will now be more likely to pay attention to the HNQs and visit other sites that they are interested in.  EDIT: Regarding the marked duplicate, ... That question is similar, although it sparked answers closer to "here's a workaround you can implement to achieve this functionality", rather than a discussion of whether this functionality should be implemented into the site. I think it's also worth revisiting this idea, as it seems the answer 4-5 years ago was "We're going to try some other things to improve HNQs before considering this," and obviously those things have been tried, to varying levels of success. I also think that the recent events around HNQs give this idea more merit.  In addition, most of the previous suggestions came from a place of "I want to exclude a site from my HNQs", whereas, this one comes from both directions, including "I want to include an excluded site in my HNQs". For example, I really enjoy Interpersonal SE, and it, along with the Workplace SE, are my big reasons for looking at the HNQs. Since it has been excluded, I have (1) not spent as much time looking at the HNQs, and (2) almost stopped looking at Interpersonal SE, due to the inconvenience.  The idea of excluding sites or questions for non-practical reasons (i.e. a title not being in English) is a fairly new one, as far as I am aware, and I think it warrants a revisiting of this suggestion.

I was going to make a filter for the "" by excluding some sites from it.  I noticed  which talks about "negative filtering" but does not explain how one can do it or if it is possible.  There does not seem to be a way to do this, though.  On the filter page, my only options are:  So how can I do "All sites except [list]"? It would also be nice if this could include similar functionality with the meta checkbox.  Something like "All main & meta sites except..."


Now that the jailbreak for iOS 9.2.1 has been released, can I downgrade my iPad Mini 1 to older versions? It is so slow with 9.2.1.

I'm trying to downgrade my iPhone from the current iOS to an older one, as per .  But every time I try, I always receive this error:     The iPhone could not be restored. This device isn't eligible for the requested build.     I have tried many times with and without DFU mode. Any ideas regarding this?


Is it possible to show :  lot # area dimensions of the polygon's lines highlighted polygon  with the only input being the lot #. The result should look like this:

Using native QGIS layer property definitions, I have successfully labelled each polygon in my layer with its area and perimeter.  Never satisfied, I now wish to label each side of each polygon with its length.  It would seem to be a common-enough requirement but I'm not getting good hits.


In R I can sample from a multivariate normal distribution as follows:  n         <- 100 # sample size mu        <- c(1, 5) # mean for each distribution            Va        <- c(0.2, 1) # variation for each distribution         CORa      <- 0 # correlation between the two                      Cova      <- CORa*(sqrt(Va[1])*Va[2])  # covariance between the two VCVmatrix <- matrix(c(Va[1], Cova, Cova, Va[2]), 2, 2) # variance-covariance matrix MVNData   <- mvrnorm(n, mu, VCVmatrix) # function for multivariate randome normal sampling        But I want to be able to replicate this without using the mvrnorm function (I've to create these data in a different language that doesn't have this function).  Someone at stackoverflow suggested this but it's not working out exactly right:  rho <- 0 dim1 <- rnorm(100, 1, 0.2) dim2 <- rho * dim1 + sqrt(1 - rho ^ 2) * rnorm(100, 5, 1)   If I compare the histograms of the distributions from the two methods, dim1 seems to have a much smaller variation than MVNData[,1].   hist(MVNData[,1], col='blue') hist(dim1, col='red',add=T)  hist(MVNData[,2], col='blue') hist(dim2, col='red',add=T)   Hope you can help.

Does anyone know of a tool that I can use to generate a set of data with known correlations (and to put the icing on the cake - output this in json,csv,txt or some common format)?  I am working on some data visualizations and want to evaluate which ones can more easily allow a user to spot correlations - visually.


I am not new to Apache but nor am I an expert (by any means). I've run sveral versions of WAMP and XAMP server set-ups. Most of my Apache configurations are simple. I usually run a default master configuration file (httpd.conf or apache.conf) and one or two includes (with a different port, for example) and some site-specific virtual host files.  Recently, I set up a server to use HTTPS. I bought certificate and set it up. It wasn't too bad, but it got me thinking. Each Apache configuration I set up seems to be a bit different. I don't apply any best practices; just bits and pieces built up from a default installation using only those changes to make my application run.  This is now bothering me. I run Apache 2.2 currently and I would like to adopt a convention for myself with which I can keep consistent, one that I could more easily deploy to more servers in a quicker fashion.  So my question is, what files should I use and how should they interact? For example, I think most people agree that loading up your main Apache configuration with tweaks is a bad idea. So should you strip it down to the bare minimum and implement multiple includes? How do you properly set up the sites-available directory (sites-enabled filled with symlinks)? Because there are many ways to do things and since Apache allows for directives to be used in multiple places with the same affect, I find that bits and pieces get spread out over all these files, including using something like mod_rewrite in an .htaccess file (which I'm starting to believe is a bad idea unless you are on shared hosting where that's the only way).  For SSL, do you set up a default-ssl file or project-ssl. How many virtual hosts do I run on one server?  I understand that my question is somewhat subjective. There is probably not an objective answer. But my my goal is to get as close to an objective answer as possible.  Then there is WSGI. If you deploy Django sites, this further complicates things. Should I use /home/user/project/project/wsgi.py or /var/www/project/index.wsgi? How do these files interact with the Apache configuration?  Here is a list of files that I'm concerned with:  /etc/apache2/apache.conf /etc/apache2/httpd.conf /etc/apache2/ports.conf /etc/apache2/envvars (mostly self explanatory) /etc/apache2/conf.d/project.conf /etc/apache2/conf.d/security /etc/apache2/sites-available/default /etc/apache2/sites-available/default-ssl /etc/apache2/sites-available/project /etc/apache2/sites-available/project-ssl   Why do some Apache installations have an Apache main configuration with modules included and others have mods-available and mods-enabled?  Like I said above, there seems to be a lot of overlap so I'm not surprised that this is a tricky topic to master.  Alternatively, if anyone knows a good reference that steps through this, I'd be interested in seeing it. I have a couple older Apache books and they just don't break it down. They assume you are complete beginner and that you leave the default alone. The Apache docs are pretty good and I go to them often, but a comprehensive source for what I'm looking for doesn't seem to exist (or, I haven't found the best search terms to find it).

This is a  about  the use of a *AMPP's stack.    I recently had a talk with some experienced people and they suggested to me not to use a WAMP stack, and instead install apache, mysql and php separately.  I don't understand why they have suggested this, though, so can anyone tell me?  Is there a particular disadvantage of WAMP, or a particular advantage to installing all of them separately?  Since a WAMP stack itself is composed of apache, mysql and php, then what's the difference between using the WAMP stack and installing them all separately?


I've seen this across nine different Stacks I follow, so I presume it's everywhere.  The last few days, I've been getting a little box in most (all?) questions with a bell icon inside and "get updates on questions and answers" -- but there's no active text in the box, the bell isn't active, and the only function that appears to be available is to close the box with the X in the upper right.  Is this a preview of an upcoming feature, a bug, or a bugged/failing feature that's supposed to be live? I've looked in other parts of the UI and don't see anything that lets me specifically follow a given question or answer. What's up with the bell box?  (referred here from boardgames.meta.stackexchange.com)

We are happy to announce that the  follow question and answer feature is now live across the Network, including Stack Overflow, all Stack Exchange sites, and all Meta sites. (International Stack Overflow sites will have it turned on in a day or two once we have translations all set.) You can follow any question or answer (that you did not author) by clicking on the [follow] button that is shown in the menu immediately below the post (alongside the [share] button):    After you have followed a post, you will get inbox notifications for all new answers (in the case where you followed a question), comments, edits, and notices. You will not receive notifications for any action that you performed. As was mentioned in the earlier post, we are not making changes at this point to the notifications received by a post owner, or due to @mentions. The initial release had been planned to only include question following. Thanks to many folks who chipped in over the past few weeks, we are happy to release both question and answer following at the same time. These are available in both the regular and mobile views. We are still planning on two more related releases:  Follows profile tab and question listing filter: A tab for follows will be added to your user profile activity page. Each user will be able to view this tab that will provide a listing of followed questions and answers, with standard sorts, and the ability to unfollow from the listing. Users (with the exception of moderators and authorized staff) will not be able to see this information about other users (nor will it be made public in the API, SEDE, or data dumps). We will be renaming the Favorites feature to Bookmarks. As we mentioned in the preview post, the feature will be the same as Favorites, with the name and icon updated to more accurately represent user expectations and usage. And you will be able to both "bookmark" and "follow" a question.  We hope that this new feature will allow you to have better access to the content that you care about and want to keep tabs on. Update (June 11, 2020): The user profile tab and the rename of Favorites to Bookmarks have been released.


How do you prove that the general norm equation $\sqrt[p]{\displaystyle\sum_{n=1}^{m} |x_n^p|}$ satisfies the inequality $\sqrt[p]{\displaystyle\sum_{n=1}^{m} |x_n^p|}\leq {\displaystyle\sum_{n=1}^{m} |x_n|}$? I think I'm pretty close, I have taken both sides to the $p$ power such that ${\displaystyle\sum_{n=1}^{m} |x_n^p|}\leq \left( {\displaystyle\sum_{n=1}^{m} |x_n|} \right) ^p$ where the RHS is the multinomial expansion  $${\displaystyle (x_{1}+x_{2}+\cdots +x_{m})^{n}=\sum _{k_{1}+k_{2}+\cdots +k_{m}=n}{n \choose k_{1},k_{2},\ldots ,k_{m}}\prod _{t=1}^{m}x_{t}^{k_{t}}\,,}$$ where $${\displaystyle {n \choose k_{1},k_{2},\ldots ,k_{m}}={\frac {n!}{k_{1}!\,k_{2}!\cdots k_{m}!}}}$$ From there, I need to somehow out a  ${\displaystyle\sum_{n=1}^{m} |x_n^p|}$ from the above multinomial summation.  One side question, is this in fact the triangle inequality at all? Either way, I'm pretty sure this inequality is valid since any such expansion should result in ${\displaystyle\sum_{n=1}^{m} |x_n^p|} \leq {\displaystyle\sum_{n=1}^{m} |x_n^p|} + K$ where K is a combination of all the ways the variables $x_1, x_2, x_3 \cdots x_m$ can be multiplied together, so it must be positive since the variables each represent a nonnegative length.  Edit: I see there is a method to prove this by taking the limit of the sum after showing this for the L2 norm. However, I am still interested in knowing how to solve for this $K$.

I can't seem to work out the inequality $(\sum |x_n|^q)^{1/q} \leq (\sum |x_n|^p)^{1/p}$ for $p \leq q$ (which I'm assuming is the way to go about it).


I put a bounty on another question and someone , but the answer contains a .zip file, because Stack Exchange has a limit on the maximum post length and the code exceeds that. Problem: The .zip file is hosted on the author's own website, and that website might not be available anymore one day, and an important part of the answer will be lost. How should I deal with the situation? Ask the answer author to upload their code on GitHub?

The basic scenario is that, in the course of answering a question, I might do a few searches and not really find a suitable link for additional information. If I've got some spare time and I'm familiar with the topic, it may make sense for me to write up an appropriate document, revisit my answer, and add the link.  Similarly, I might have some old code lying around that can be tidied up fairly quickly and contributed as an example - but it may be too big to just insert into an answer. A few snippets to illustrate the principle makes sense, but providing the full example has value too.  The problem is, where do I put these things?  I have a couple of options, of course - free ISP web space, free web hosts, a commercial host aimed at small sites, free file hosting etc - but they don't really seem quite appropriate to me.  The issue is that, like the questions and answers, I think these contributions should be editable by the community.  Is there a good or approved way to handle this kind of thing? Is it a real problem at all?


The compiler (g++-7) emits an error when compiling the following code:  #include <vector>  template<typename MetricType, typename DataType> class Label {   public:     using metric_type = Label<MetricType, int>;      template<typename LabelDataType> using label_type = Label<MetricType, LabelDataType>;   // ... };  template<typename LabelType> class Raptor {   public:     std::vector<typename LabelType::metric_type> works;      std::vector<typename LabelType::label_type<int> > throws_an_error; };  int main() {   Raptor<Label<int, int> > raptor;   return 0; }   The error message is  main.cpp:17:53: error: template argument 1 is invalid      std::vector<typename LabelType::label_type<int> > throws_an_error;                                                      ^ main.cpp:17:53: error: template argument 2 is invalid make[2]: *** [CMakeFiles/bin.dir/build.make:63: CMakeFiles/bin.dir/main.cpp.o] Error 1 make[1]: *** [CMakeFiles/Makefile2:73: CMakeFiles/bin.dir/all] Error 2 make: *** [Makefile:84: all] Error 2   I tried giving the std::vector an empty struct as the second template argument, but the error message stays the same.  I have no idea what this error message means and how to make this code compile. Especially I'm confused, because the field works does not produce any errors, also when commenting the errorneous field out, but the types metric_type and label_type<int> are equal.

In templates, where and why do I have to put typename and template on dependent names? What exactly are dependent names anyway?    I have the following code:  template <typename T, typename Tail> // Tail will be a UnionNode too. struct UnionNode : public Tail {     // ...     template<typename U> struct inUnion {         // Q: where to add typename/template here?         typedef Tail::inUnion<U> dummy;      };     template< > struct inUnion<T> {     }; }; template <typename T> // For the last node Tn. struct UnionNode<T, void> {     // ...     template<typename U> struct inUnion {         char fail[ -2 + (sizeof(U)%2) ]; // Cannot be instantiated for any U     };     template< > struct inUnion<T> {     }; };   The problem I have is in the typedef Tail::inUnion<U> dummy line. I'm fairly certain that inUnion is a dependent name, and VC++ is quite right in choking on it. I also know that I should be able to add template somewhere to tell the compiler that inUnion is a template-id. But where exactly? And should it then assume that inUnion is a class template, i.e. inUnion<U> names a type and not a function?


Suppose I set $ax+by=1$ such that $x, y$ are integers and $a$ and $b$ are elements.   The greatest common divisor of $a, b$ is $1$.   If $a=bc$, then $bcx+by=1$.   But then what do I do?

Well I thought this is obvious. since $\gcd(a,b)=1$,  then we have that $a\not\mid b$ AND $a\mid bc$. This implies that $a$ divides $c$. But apparently this is wrong. Help explain why this way is wrong please.   The question tells you give me two relatively prime numbers $a$ and $b$ such that $a$ divides the product $bc$, prove that $a$ divides $c$. how is this not obvious? Explain to me how my "proof" is not correct.


Consider this question: A helium balloon is held by a light string in the middle of the back of a very powerful truck. The back of the truck is sufficiently large that the balloon cannot hit the sides if it sways forwards or backwards on the string. The back of the truck is completely enclosed with no windows or ventilation from the outside. The truck now accelerates rapidly forwards. What is the motion of the balloon relative to the truck when the truck is accelerating? Does the balloon sway forwards, backwards or remain at the same position?  Now, the balloon should move forward as the air would be pushed backwards creating the higher pressure at the back. But the answer suggests that it won't move. How is that possible?

I noticed that when I had a helium filled, latex balloon inside of my car, it moved forward in the cabin as I accelerated forward. The faster I accelerated forward, the faster the balloon went from the back of the car to the front of the car. The balloon didn't have a string.  This became a game with my 4 year old as we drove home. We figured out where the balloon would go based on how fast I accelerated, turned corners etc.  I expected that it would act a lot like the water in a cup does, but it was the total opposite it seemed.  What forces caused this behavior?  I assumed it has something to do with the fluid dynamics in the closed cabin, but I can't figure it out.


I'm looking for a package if it exists or options to deal with schemes that use curly braces. In general, how can I do something like this:

I apologize if this has already been covered in some other posts, but I couldn't find it anywhere and I'm not even sure if "brace diagram" is the correct name in English.  I have found some examples of probability trees, and some others that are close (like this: ), but while playing with them I couldn't get the correct output (The part of the first "text here" when out of boundaries into the brace).  What I'm trying to do is something like this with TikZ:    I know there are some ways to do this with mathmode, but I'm really interested in learning a little more about TikZ and how it works for diagrams like this.


On this problem, I'm not sure what Big O definition they are referring. How would the big o definition help show this? I get that $|y-y_h|$< $M\beta (h)$, where $y_h$ is an approximate value to y at some point h, but don't really understand the question  Use the definition of $O$ to show that if $y = y_h + O(h^p)$, then $hy = hy_h + O(h^{p+1})$.

On this problem, I'm not sure what Big O definition they are referring. How would the big o definition help show this?  Use the definition of $O$ to show that if $y = y_h + O(h^p)$, then $hy = hy_h + O(h^{p+1})$.


The Question: I believe I’m right here, but I wanted to get some consensus before I rely on it in a game: Can I apply the ability: "{U}: Untap Soliton" to a different Soliton than the one that activated the ability? The Brief I’ve been looking for an infinite mill combo using  for a long time, and have been unable to find one, but I have come close. I now have a plan that will at least allow me to mill a player so much that it doesn’t matter that I can’t get the infinite mana needed to make the loop unending. The Steup:  Soliton has the ability:  {U}: Untap Soliton    has the ability to Soulbond, and if soulbonded has the ability:  {T}: Target player puts the top two cards of his or her library into his or her graveyard   If soulbonded to Stern Mentor, Soliton will also have the ability:  {T}: Target player puts the top two cards of his or her library into his or her graveyard    In a simple set up, of one Soliton soulbonded to one Stern Mentor, I can tap Stern Mentor and mill for two, then tap Soliton and mill for a further two, then pay one blue mana to untap Soliton, then tap Soliton to mill for two and so on… Assuming I have ten blue mana free this will allow me to mill for 24. The Issue: If I have two sets of Stern Mentor soulbonded to Soliton I can’t mill for any more than if I had just the one set because I am restricted by the amount of mana I have. The Plan: I also have several . These have the ability:  Whenever an ability of equipped creature is activated, if it isn't a mana ability, copy that ability. You may choose new targets for the copy.  Now I had originally hoped to clone Soliton’s ability onto an island card and create an infinite mana combo, but then I realised that if I cloned the ability: "{U}: Untap Soliton" onto something else the ability would still be "{U}: Untap Soliton", and I couldn’t untap the same Soliton that had just been untapped. I’m hoping that I can apply that ability to my other Soliton, that way, if I have two sets of Soliton equipped with Illusionist’s Bracers and soulbonded to Stern Mentor, I can tap one to mill, clone the mill ability inherited from Stern Mentor, do the same for the other set, then untap one Soliton and clone the ability across to the other. This will allow two to be untapped for the price of one. If we disregard cloning the ability inherited from the Stern Mentor this would up the mill to 44, but with the inheritance it would up the mill to 92. With 20 mana spare that we be upped to 184, that can be spread across as many players as I like.

Many abilities in MTG use a permanent's name in the ability. Does this mean that if I have 2 copies of that permanent, the ability will affect both permanents?  Activated ability example:  - If I activate the ability of one of my Vector Asps, can I choose which of them gain infect until end of turn? Or will they both gain infect?  Triggered ability example:  - If I cast a second Sin Collector, when it enters the battlefield, will each Sin Collector trigger and allow me to exile a total of 2 cards instead of 1?


I have bought a domian that is like service.city.example Where service is eg. "haircut".  Is it good to have this kind of domains as aliases to main domain company.example?  What would be best for SEO, serving the main domain content on this alias or redirect 301 from alias to main domain?

Lets say I have a domain already, for example www.automobile4u.com (not mine), with a website fully running and all.  The title of my "Website" says:    <title>Used cars - buy and sell your used cars here</title>   Also, lets say I have fully SEO the website so when people searching for the term buy used cars, I end up on the second or first page.  Now, I want to end up higher, so I go to the google adwords page where you can check how many searches are made on specific terms.  Lets say the term "used cars" has 20 million searches each month.  Here comes the question, could I just go and buy that domain with the search terms adress, in this case www.usedcars.com and make a redirect to my original page, and this way when people search for "used cars", my newly bought domain name comes up redirecting people to my original website (www.automobile4u.com)?  The reason I believe this benefits me is because it seems search engines first of all check website adresses matching the search, so the query "used cars" would automatically bring www.usedcars.com to the first result right?  What are the downsides for this?  I already know about google spiders not liking redirects, but there are many methods of redirecting...  Is this a good idea generally?


There are some one-way transparent glasses.  Light can pass the glass in this way, but cannot in the other way around.   It is quite contrary to the experience that the path of light is reversible.   So what is the reason behind?

How does a  work? If seen from the outer side, we can see through thinking it is transparent, while if seen from the inside, the glass acts as a mirror. How?


Let us consider the sequence $(a_n)_{n \ge 1}$ such that  $$a_n=\frac {1}{\sqrt {n^2+1}}+ \frac {1}{\sqrt {n^2+2}} + \dots +\frac {1}{\sqrt {n^2+n}}.$$ Show that the sequence is not monotone.  I found the problem, but the solution is wrong.

Let we have the following sequence  $$y_n= \frac{1}{\sqrt{n^2+1}}+\frac{1}{\sqrt{n^2+2}}+\cdots+\frac{1}{\  \sqrt{n^2+n}}$$ find the limit of the sequence $y_n$ decide whether it is increasing or decreasing


If I am NOT using a reference to a pointer when sending the base-pointer to another class constructor - and in this class binding the basepointer to a derived object of the base - the basepointer returns NULL.   Simply - what is the reason for this?   #include <iostream> using namespace std;  class Base {    public:       virtual void print() = 0; };  class Sub1 : public Base { public:    void print() {       cout << "I am allocated!\n";   } };  class App { public:     App(Base *b) {       b = new Sub1;    } };  int main() {    Base *b;    b = NULL;     App app(b);     if (b != NULL)       b->print();    else       cout << "Basepointer is NULL\n";     return 0; }   The crucial part here is the signature of the App-class constructor  when not using a reference to the basepointer i.e     App(Base *b)   the output is:     Basepointer is NULL   And when using a reference to the base-class i.e.    App(Base *&b)   the output is:   I am allocated!

I would like to clarify the differences between by value and by reference.  I drew a picture     So, for passing by value,  a copy of an identical object is created with a different reference, and the local variable is assigned the new reference, so to point to the new copy  How to understand the words: " If the function modifies that value, the modifications appear also within the scope of the calling function for both passing by value and by reference "  Thanks!


It's 19:01 now. This is what the Scheduled Tasks window on my Windows Server 2016 shows:    As you can see, the highlighted task is:   triggered to run at xx:15 every hour, is scheduled to run again at 19:15 and last ran at 16:15.   When I checked about an hour ago, the "Next Run Time" was "08.02.2017 18:15:00". However, as you can see in the screen shot, it did not run, and the task history does not tell me why.  For completeness, the remaining settings of the task are:   General tab: SYSTEM account, "run with highest privileges". Conditions tab: none checked. Settings tab: "Allow task to be run on demand", "Stop the task if it runs longer than 3 days" and "If the running task does not end when requested, force it to stop" are checked. If the task is already running, "Do not start a new instance" is selected.   What steps can I take to find out why the task does not start sometimes?

We have a 2012 server that has about 20 scheduled tasks that are used for monitoring.  We have built a 2016 server to replace it and as I move tasks to the new server I have run into an issue.  Most of our tasks run every few minutes.      In Server 2012 we would schedule the task to start at 1200AM of the current day (so a time in the past) and reoccur every X minutes.  The task would start at its next scheduled time.  Perfect.  In Server 2016 schedules that start in the past don't run.  So we had to schedule it to start in the future.  This is fine until you reboot.  Now the start time is in the past and it won't run.  It doesn't even register a failed run.  The Next Run Time column shows that it should run but doesn't.    Besides creating two triggers, one that starts in the future and another that starts on reboot (which we don't want to do since some tasks should only run at specified times), is there a better way?  This seems to be a bug.  The 2012 version worked great.  UPDATE  There is a workaround for this.  Create a one time schedule that runs indefinitely.  This works after restarts just like you would expect.  I know this isn't great for schedules that are "weird" but works fine for things that we want to run every 3 minutes or whatever.


I am working on an existing asp classic site and there are links that work but I don't understand how they are working. I have a link /shoponline/threads/threadreg and when I look at the site structure, there isn't a /shoponline/threads folder, but there is a /shoponline/thread.asp page and there is a /shoponline/threadT.asp page. There are a few examples like this on the site where the link ends in a plural like /shoponline/fabrics but the file it points to seems to be /shoponline/fabric.asp. Can someone explain how this link works?

Is there a mod_rewrite equivalent for IIS 7.0 that's   a) more or less complete   b) suitable for a production environment, i.e. battle-tested/dependable/secure  Do you have an experience-based recommendation?


Initially I had to show that for $0\le n \le 1$ and $a,b > 0$:  $$a^n + b^n \ge (a+b)^n$$  I made $u(x) = a^x + b^x - (a+b)^x$  $$u'(x) = a^x \log a + b^x \log b - (a+b)^x \log (a+b)$$  Now I get stuck. Cannot find where to go. please help me.

Prove $(|x| + |y|)^p \le |x|^p + |y|^p$ for $x,y \in \mathbb R$ and $p \in (0,1]$.  A hint is given that for $0 \le \alpha \le \beta$ there exist a number $\xi \in (\beta, \alpha + \beta)$ s.t. $$(\alpha + \beta)^p - \beta^p = p \xi^{p-1}\alpha \le \alpha^{p}$$.  I see that by proving the above hint the result holds for positive numbers.  In order to prove the above hint I've considered the Intermediate value theorem, however I've not yet succeeded.


I have a ASP.NET MVC 4 website bound to a MS SQL Server database. I can see among the many aspnet_ stored procedures some custom ones.  How do I know if these custom stored procedure are in use? Should I check the C# code or something else?  Thanks.

Is there an easy way to chase down table/stored procedure/function dependencies in SQL Server 2005+?  I've inherited a giant application with lots of tables and even more stored procedures and functions that are long and interlinked.    At the end of the day is there a way to build a dependency tree?  Ideally what I'm looking for goes in both directions:  For a table/procedure - what depends ON it?:  Show me all the stored procedures that eventually reference it (ideally in a tree view such that sub procedures nest out to the bigger procedures that call them)  For a procedure - what does IT depend on?:  Show me all the procedures and tables that a given procedure will (or could) touch when running.  It seems this tool shouldn't be that hard to make and would be incredibly useful for DB maintenance generally.  Is anyone aware of such a thing?  If this doesn't exist, why the heck not?  The built-in functionality in Management Studio is nice but the information does not appear to be complete at all.


I have a simple question I made my self but didn't find any answer and hints.  When I type for the man entries of a command, e.g. "man git", I get the following:  ...  DESCRIPTION        ...         See gittutorial(7) to get started, then see Everyday Git[1] ...        The Git User's Manual[2] has a more in-depth        introduction.         After you mastered the basic concepts, you can come back to this page to learn what commands Git offers. You can learn more about individual Git        commands with "git help command". gitcli(7) manual page gives you an overview of the command line command syntax.         Formatted and hyperlinked version of the latest Git documentation can be viewed at http://git-htmldocs.googlecode.com/git/git.html.   Could someone explain what are those "See gittutorial(7)...Everyday Git[1]...gitcli(7)" etc.? I mean, I know that they are telling "look at this resource if you want to know the basic concepts, for more info, etc.", but actually how should one interpret it? What is the meaning of the numbers (like 7, 1, 2, etc..) inside the parenthesis or brackets? And where I can find the resources the manual is telling me to see, do I have to type something in the man prompt, or search on the Internet?   I just would like to ask for an elucidation.   Thank you for your attention!

For example: man(1), find(3), updatedb(2)?   What do the numbers in parentheses (Brit. "brackets") mean?


I found the solution of series on Wolfram Alpha   for $\alpha = 1$  $\sum\limits_{k=1}^{n/2} \left(\frac{1}{\left(2k-1+2^{1/\alpha}\right)^\alpha} - \frac{1}{\left(2k+2^{1/\alpha}\right)^\alpha}\right)=\frac{1}{2} \left(-H_{\frac{n}{2}+1} + H_\frac{n+1}{2} -1 + \text{ln}(4)\right)$  Can someone tell how to prove this in the form of Harmonic numbers?

I found the solution of series on Wolfram Alpha    $ \sum\limits_{k=1}^{n} \left(\frac{1}{2k+1} - \frac{1}{2k+2}\right) = \sum\limits_{k=1}^{n} \frac{1}{(2k+1)(2k+2)} = \frac{1}{2} \left(H_{n+\frac{1}{2}} - H_{n+1} -1 + \text{ln}(4)\right)$  Can someone tell how to prove this in the form of Harmonic numbers?


I would like to annotate a figure with subfigures using latex such that the columns are labelled 'models' 1 -3 and rows labelled 'parameter 1 - 5'. Here is an example of desired output:    The only difference is that I would like the row annotation to be horizontal? Is this possible ?   Please note, I'm reasonably new to latex so I'm okay with the simplest solution and not necessarily the most elegant. Thanks  Edit  Just to address a question in the comments, this figure is being generated using figure and subfigure environments.

Is it possible to make a 3 by three grid of plots in a latex figure and then label only the columns and rows, rather than needing captions for each? So for example, I'd like columns to be labelled A, B and C and the rows 1, 2, and 3. I'd then be able to reference square (2, B) as the middle square.   I'm using a figure environment with 9 subfigure environments  \begin{figure*}[t]     \begin{subfigure}{0.3\textwidth}         \includegraphics[width=\linewidth]{/path/to/img1}     \end{subfigure}%     \begin{subfigure}{0.3\textwidth}         \includegraphics[width=\linewidth]{/path/to/img2}     \end{subfigure}%     \begin{subfigure}{0.3\textwidth}         \includegraphics[width=\linewidth]{/path/to/img3}     \end{subfigure}      \begin{subfigure}{0.3\textwidth}     \includegraphics[width=\linewidth]{/path/to/img4} \end{subfigure}% \begin{subfigure}{0.3\textwidth}     \includegraphics[width=\linewidth]{/path/to/img5} \end{subfigure}% \begin{subfigure}{0.3\textwidth}     \includegraphics[width=\linewidth]{/path/to/img6} \end{subfigure}      \begin{subfigure}{0.3\textwidth}     \includegraphics[width=\linewidth]{/path/to/img7}     \caption{Smad7 reproduced} \end{subfigure}% \begin{subfigure}{0.3\textwidth}     \includegraphics[width=\linewidth]{/path/to/img8} \end{subfigure}% \begin{subfigure}{0.3\textwidth}     \includegraphics[width=\linewidth]{/path/to/img9} \end{subfigure}       \caption{} \end{figure*}


May I ask what's the differences between libpam-ldap and libpam-ldapd when it comes to included packages and modules?  As i understand is nss-pam-ldapd the project of libpam-ldapd, which is an improvement of nss_ldap. So, is nss_ldap the same as libpam-ldap or is it just the NSS which is included in the libpam-ldap package which as been improved, and everything else is the same?  Trying to write a report, but cannot understand what's included in those two packages, especially in libpam-ldap.

On my servers I have my system users provisioned with Chef and have no desire to expose any additional users to these machines. I would however like to utilize pam for the authentication backend for my monit dashboard.  Do I need to set up libnss-ldapd to make pam_ldap work? Or am I thinking about this the wrong way. Would it really matter if I set up nss if /etc/pam.d/common-* don't use pam_ldap?


I have strings in currency format which i have to convert to float without using any js library.  2 079,15 EUR as an example should return 2079.15  Is there a simple way to do it ?     the solution proposed in  is not working in this case:      As it will return 207915 in case of 2 079,15 EUR instead of 2079.15      And will return 2079 in case of 2 079 EUR      A working solution should return even:   207915 in the 1st case and 207900in the 2nd case   or 2079.15 in the 1st case and 2079in the 2nd case.      The solution :  works in case of local "US" or "en-GB" but does not work for "FR".

I have a text box that will have a currency string in it that I then need to convert that string to a double to perform some operations on it.   "$1,100.00" → 1100.00  This needs to occur all client side. I have no choice but to leave the currency string as a currency string as input but need to cast/convert it to a double to allow some mathematical operations.


I have just upgraded to Ubuntu 13.10, and when I try to shut down the system, by using the up-right button of the screen, nothing happens. I have to switch off the computer manualy. Can anyone help me?

After the update neither my desktop (Asus) nor my laptop (HP) respond to the shut-down, log off or restart commands in the right top tool bar.  How do I fix the issue?