Fairly basic question, imagine  int a = 5; int[] b = new int[1]; b[0] = 5;   Do both a and b take up the same space in memory? I assume b is larger than a as it has to store the length of itself somewhere, so I thought it would be IntPtr.Size larger, but I am not sure.   I am trying to write code where the length of the array is determined at runtime, and can be 1 or larger (<10). I didn't know if I should just make an array if the length is set to one, or to have a special case in the code and just use the underlying type for length == 1.  I know that a is a value type while b is a reference type.

What is the memory layout of a .NET array?  Take for instance this array:  Int32[] x = new Int32[10];   I understand that the bulk of the array is like this:  0000111122223333444455556666777788889999   Where each character is one byte, and the digits corresponds to indices into the array.  Additionally, I know that there is a type reference, and a syncblock-index for all objects, so the above can be adjusted to this:  ttttssss0000111122223333444455556666777788889999         ^         +- object reference points here   Additionally, the length of the array needs to be stored, so perhaps this is more correct:  ttttssssllll0000111122223333444455556666777788889999         ^         +- object reference points here   Is this complete? Are there more data in an array?  The reason I'm asking is that we're trying to estimate how much memory a couple of different in-memory representations of a rather large data corpus will take and the size of the arrays varies quite a bit, so the overhead might have a large impact in one solution, but perhaps not so much in the other.  So basically, for an array, how much overhead is there, that is basically my question.  And before the arrays are bad squad wakes up, this part of the solution is a static build-once-reference-often type of thing so using growable lists is not necessary here.


Is it correct to make a sentence interrogative only with question mark (and tone) and without following essential grammatical rules?  For example, people usually say     You are going to the stadium?   instead of      Are you going to the stadium?   But, what about writing? I think doing so in writing may be problematic. Is there any specific rule for that?

For example, I found the following sentence written by a native English speaker (UK) so I'm going to assume that he knows how to put it the right way, although I wouldn't use this form.     I now have a bit more time to fix bugs   etc but I'm open to offers if anyone   wants to help maintain this module   with me?   Is it correct or is the question mark misused here?


I wanted to have a go at creating my very own Linux Distribution. Could you suggest some nice and easy-to-follow tutorials (preferably text based and not videos). I have heard something about Arch Linux but I don't know how to go from there. What do I need?

Some of my friends and I are interested in starting a new Linux distro. How do we do that? What do we need to plan? Backstory I represent a community of Linux sysadmins/implementors whose special needs include, among others:  A specific 'lean' kernel config Package management that fits our 'field needs' Binary packages optimized for our 'use cases' X-less system  To the point: We have need of a specially-configured production-quality Linux distribution to be run exclusively as Para-Virtualized Production Servers. Rather than jumping through all the hoops and loops every time we need a VM-ized Server, we would very much like a semi-prepared system, optimized for its environment. Since these VMs would be Production Servers, stability is a must, and honestly the available package management systems we're currently aware of just do not provide assurance. Zypp and Conary are the closest ones to our needs, but again still miss on some points.


Is there any difference between a directory name such as  mydirectory   and  mydirectory/   I noticed this happens when I execute ls in some directories - some of the directory names have a slash and some don't. This is problematic because if I want to access a file contained in a directory, I may need to add a slash at the end:  vi $mydirectory"/"$myfile   or simply do   vi $mydirectory$myfile

I'm working on a python script that passes file locations to an scp subprocess. That's all fine, but I'm in a situation where I may end up concatenating a path with a filename such that there's a double '/ in the path. I know that bash doesn't care if you have multiple file separators, but I'm wondering how exactly that is rectified. Is it bash that strips extra /s or does it really not matter ever?  I ask because it will save me several lines of code to check for extra /s while concatenating. I know it's not a big deal, but I'm curious as well. I have a bash script that has the line cd //usr (instead of cd /usr), which seems to imply there might be a significance to using multiple /s in a path


In relativistic physics, paricularly in General Relativity and Quantum Field Theory, we often find the use of the two terms 'invariance' and 'covariance'. But I couldn't find any mention of the difference between the two terms.  Are these two terms different or are they same? What do they exactly mean?

Just wondering about the definitions and usage of these three terms.  To my understanding so far, "covariant" and "form-invariant" are used when referring to physical laws, and these words are synonyms?  "Invariant" on the other hand refers to physical quantities?  Would you ever use "invariant" when talking about a law? I ask as I'm slightly confused over a sentence in my undergrad modern physics textbook:     "In general, Newton's laws must be replaced by Einstein's relativistic laws...which hold for all speeds and are invariant, as are all physical laws, under the Lorentz transformations." [emphasis added]      ~ Serway, Moses & Moyer. Modern Physics, 3rd ed.   Did they just use the wrong word?


In textbook ordinary least squares we want to find a vector of coefficients $b_{k+1\times n}$ such that the sum of the squared deviations of what's observed ($y_{n\times 1}$) from what's assumed to be systematic $Xb$ (or $u'u$ for $u=y-Xb$) is minimized. In addition to the observables $y,X$ we make assumptions about the distribution of $u$ eg $u\sim N(0,1)$.  Is it possible to solve for the inverse linear problem ie. given observables $X$ and an arbitrary but given $b^*$ vector of coefficients, we wish to derive those $y$ that would have produced as a solution of the direct problem, the exact vector $b^*$?  My Approach  I have tried producing $u$ such that for $g=X'u$, $g'g$ is minimized but the result does not produce reasonably looking $y$'s even though when the $y's$ are used in the direct problem as a dependent variable yields the desired $b^*$'s.  (The generated $y$ data seem to be evenly dispersed above and below the regression line, leaving a narrow corridor around the regression line empty, as illustrated below:  ).  Motivation  The motivation is to be able to generate datasets (collections of $n$ $y$'s) that display persistently the desired regression line (given by the $b^*$'s) when OLS is used on them, for a given set of regressors $X$.

I'm giving a presentation about fitting lines.  I have a simple linear function, $y=1x+b$.  I'm trying to get scattered data points that I can put in a scatter plot that will keep my line of best fit the same equation.   I'd love to learn this technique in either R or Excel--whichever is easier.


I have main.aspx and second.aspx.The code in main.aspx:  <form id="form1">

 </form>   And in second.aspx:
     <asp:Textbox runat="server" id="txt1"></asp:Textbox>     <input type="button" id="bttn" value="send"></input>
   At the run time I'm loading second.aspx page into main.aspx div id="main".  $("#main").load("second.aspx #second");   I'm trying to get the textbox value from main.aspx.But when I tried   $("#bttn").click(function(){     var t=$("txt1").val();     alert(t); });   It gives nothing.It seems to be never going into the function.How can get the value from the textbox.

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 set a post to private on a WordPress multisite so users should be redirected to a 404 page. The permalink of this post is http://local.website.com/en/event.  Now WordPress seems to redirect requests to event to event-30-01-2016. WordPress seems to focus on the lower number after the event string. Example: it will prioritise event-29-05-2015 over event-30-05-2015.  I want to keep the URLs for posts like event-* but I want event to redirect to 404 since I kind of disabled the page.  My settings on /wp-admin/options-permalink.php are set to Post name.  I don't have any special rewriteRules in .htaccess for events.  This is my .htaccess:  # BEGIN WordPress RewriteEngine on RewriteBase / RewriteRule ^index\.php$ - [L]  # add a trailing slash to /wp-admin RewriteRule ^([_0-9a-zA-Z-]+/)?wp-admin$ $1wp-admin/ [R=301,L]  RewriteCond %{REQUEST_FILENAME} -f [OR] RewriteCond %{REQUEST_FILENAME} -d RewriteRule ^ - [L] RewriteRule ^([_0-9a-zA-Z-]+/)?(wp-(content|admin|includes).*) $2 [L] RewriteRule ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L] RewriteRule . index.php [L] # END WordPress   Is there maybe a hook that I could use in order to disable this kind of redirection?

Wordpress has a feature whereby it will automatically redirect your URLs if it percieves them to be written wrongly. Here is an example: I have a page called my-page  If I go to:  www.mysite.com/something/my-page/   it will immediately redirect me to   www.mysite.com/my-page/   as nothing exists at the first URL.   How can I turn this feature off, and instead just get a 404 if incorrect URL's are typed in?


I want to copy a object from Illustrator and paste it into a Photoshop document with the same color mode and profile.    When I use the Eyedropper Tool on the pasted object in Photoshop the color seems to be slightly off.    Both the Illustrator and the Photoshop document have their Color Mode set to RGB.    Both Applications are using synchronized color settings.    This also happens when the object is dragged or Placed. It does not happen when copying from Photoshop to Illustrator.  Could there be a problem with my color management settings? What actually happens to the color information, when it is copied from one application to another?

What I want to achieve:  I want to copy an image in Illustrator and paste it into Photoshop. The image is just a grey circle with a #d1d1d1 fill and no stroke.  The problem:  Bottom line, the color of what I'm pasting changes.The pasted image is a different shade of grey: #d5d6d8.  What I've tried:  I've checked my color settings in both Photoshop and Illustrator (Edit > Color Settings). The settings are identical.   Any ideas on what's causing the color difference?


The title sums it all, I just am seeking an answer in the Middle Earth world, not the Tolkien nor the Peter Jackson's world. I believe it is already a singularity to find a dwarf attracted to an elf and vice versa. So is it possible for the two breeds to reproduce? If it is, what can the outcome be? A hybrid, and dwarfish elf or an elvish dwarf?  Please do excuse my lack of knowledge of the middle earth, I only watched the movies and didn't have the chance to read any written material about it, so if this is a redundant question, just let me know.

I know Tauriel is a Jackson created character, but I wondered if anywhere in the legendarium there was fodder for the story arc between her and Kili.  I do not have access to all my books for the time being and recall stories of love between men and elves in the Silmarillion and Appendices but don't remember any such stories between elves and dwarves and wondered if there was any basis of inspiration for this aspect of their relationship within Tolkien's works.   This movie, of course, departs even further from the original than those made before it, but as a story unto itself, I can still appreciate the ride, so if there is no Tolkien basis, what inspired Jackson, Boyens, and Walsh to create this particular arc?  Is there interview info or anything?


so i tried to make a grass and i wanted to change colour with colour ramp. it's a particle effect. when i change the colours and mix it only bottom base layer changes the colours. but the actual blades of "grass" stay the same one colours.

I'm trying to make carpet with a pattern. I applied an image texture to a particle emitter and it looks okay.  However I want the carpet strands to be more realistic so I made an object to emit instead..  But now I'm at a loss as to how to apply the pattern texture to the whole carpet again because the strands now take their material from the single object.


I started using Ubuntu along with Windows, then i decided to remove Windows entirely and just use Ubuntu. The problem is that everytime i boot my computer i see the grub screen, then i have to select "Ubuntu" to start the system. Altough it's not a big deal, i would like the system to boot Ubuntu immediately.  I'm using ubuntu 19.10.  Edit: i tried editing /etc/grub/defaults with any combination of GRUB_TIMEOUT et al settings i could find online and save it with update-grub but with no luck, it seems it ignores every directive i put there.

Hello can someone give me short tutorial how to:   Remove Windows 7 from my dual boot system (Ubuntu/Windows7) Let me use free space as new partition for data (so I don't need to extend Ubuntu itself here) Remove windows 7 option from boot screen   Update:  Thanks to Lekensteyn answer I successfully deleted windows. Now I created new partition (formatted to ext4), but I can not use it. I cannot copy files there, only as root.  Also when booting, Ubuntu complains it didn't find /windows partition (of course it didn't, I removed it). I feel like I should update some tables or what, any ideas?


I would like to rename files within each sub-directory by adding the name of the sub-directory. Following the answer from , I tried:  rename  's/(.*)\//$1\/$1_/' */*   However for lots of sub-directories it doesn't work. I have 13,000 sub-directories each containing about 300 files. I get  -bash: /usr/bin/rename:  Argument list too long   I tried:  ls | xargs rename 's/(.*)\//$1\/$1_/' */* find . -maxdepth 1 -type f -print0 | xargs rename 's/(.*)\//$1\/$1_/' */*   Both give the same error:  -bash: /usr/bin/xargs:  Argument list too long   EDIT  xargs -L  rename 's/(.*)\//$1\/$1_/' */* xargs -L1  rename 's/(.*)\//$1\/$1_/' */*   Same error:  -bash: /usr/bin/xargs:  Argument list too long

I just asked a  related to how I can count the files of particular extension. Now I want to cp these files to a new dir.  I am trying,  cp *.prj ../prjshp/   and   cp * | grep '\.prj$' ../prjshp/   but they are giving the same error,     bash: /bin/cp: Argument list too long   How do I copy them?


I am using VAIO T series with Win 8 preinstalled, I have installed Ubuntu 12.04.3 on a different partition and set GRUB at default. But whenever I choose to boot Win 8, the next time I start the laptop, it Windows Boot Manager which shows up at default. How can I set GRUB default constantly?

I have a Sony VAIO S series with Windows 8 preinstalled, and I installed Ubuntu 12.10 on a new partition. When the PC boots Grub is display, and I can choose between Windows 8 (didn't worked at the beginning, had to change Grub settings) and Ubuntu 12.10. When I select Ubuntu 12.10 everything is OK, but when I use Windows 8, and I restart Grub isn't displayed anymore (Windows 8 boots immediately).  I booted a Ubuntu 12.10 LiveUSB, used efibootmgr, and found out that Windows 8 (each time it boots) changes EFI default bootloader from Grub to Windows Boot Manager.  How do I change this in Windows 8? I read something about bcdedit, but it does not work or I don't know how to use it...


Say I have a large amount of input and excepted output. Can I instruct visual studio to run test methods on all elements of the collection as separate unit tests?  [TestClass] public class CalcTests {     private static IDictionary<string,string> data = new Dictionary<string,string>()     {         {"1+1","2"},         {"sin(9^180)!7", "pi"}     }      // This will run all cases, but provides little insight as cases might vary wildly in complexity     [TestMethod]     public void TestCalc()     {         foreach(var entry in data) {             Assert.AreEqual(Calc(entry.Key), entry.val);         }     } }

I know that MSTest doesn't support RowTest and similar tests.  What do MSTests users do? How is it possible to live without RowTest support?   I've seen DataDriven test features but sounds like too much overhead, is there any 3rd party patch or tool which allow me to do RowTest similar tests in MSTest?


I am making a word list from all the words typed into a program that will be working with the text entered into it.  I want to use a stream editor like sed or awk to search the first word of every line in a document and return the line number when a pattern -stored in a variable- is found. I have this much working correctly so far:  awk $1 '{print $1 " " NR""}' dictionary.txt | awk '/^**myWord** /' | cut -d" " -f2   However, I cannot figure out how to use a variable in place of "myWord". For example, I get only errors when I use:  read=searchWord  awk $1 '{print $1 " " NR""}' words.txt | awk '/^**$searchWord** /' | cut -d" " -f2

Having the following in one of my shell functions:  function _process () {   awk -v l="$line" '   BEGIN {p=0}   /'"$1"'/ {p=1}   END{ if(p) print l >> "outfile.txt" }   ' }   , so when called as _process $arg, $arg gets passed as $1, and used as a search pattern. It works this way, because shell expands $1 in place of awk pattern! Also l can be used inside awk program, being declared with -v l="$line". All fine.  Is it possible in same manner give pattern to search as a variable?  Following will not work,  awk -v l="$line" -v search="$pattern" '   BEGIN {p=0}   /search/ {p=1}   END{ if(p) print l >> "outfile.txt" }   '   ,as awk will not interpret /search/ as a variable, but instead literally.


I tried to change the HTML form, input type file. Here is my code:  HTML, form id = form  <input class="upload_file" type="file" id="file" name="file" />   .CSS  I tried both: .upload_button{   background: url('../images/upload_btn_bg.png') no-repeat;   width: 200px;    height: 40px; }  #form input[type=file]{   background: url('../images/upload_btn_bg.png') no-repeat;   width: 200px;    height: 40px; }   None of both of those methods works. I did see from some website, like facebook, youtube, google or twitter, they have different style. Wonder how they do it.

How do you style an input type="file" button?


I'm trying to identify a trio of books I read as a teenager. They were set not too far in the future with the main character getting into a series of adventures with three older soldiers(?) One of the older men walked with a cane which was really a blaster. One of the novels included the moon having been turned into a big casino and one turned on the fact that the bad guy had an allergy to the main character which was used to identify him. It's been driving me nuts for a while, any help appreciated.

I am searching for the title of a book I read a long time ago, from the style I would say that it was "golden age" sci-fi. The Earth is attacked by a race of aliens who have set up camp on the moon and are bombarding Earth with poison gas shells. Ordinarily this would not be a problem as Earth is protected by a superweapon called AKKA, that can easily see off any threat. However due to fear of it falling into the wrong hands it is stored dismantled, and the aliens have cleverly kidnapped the scientist(s) who can can reassemble it. Our heroes, who are out on space patrol beyond Pluto survive the initial attack and travel to the aliens homeworld and rescue at least one scientist and return him to Earth. There, using just bits of random junk, he constructs an AKKA device and points it at the moon, which simply vanishes along with all the aliens on it. The meaning of AKKA is never revealed in the book, as far as I can remember.   I also remember that before setting off, the heroes take a bit of time out to tune up their 6-cylinder space engine for maximum performance, that was some good thinking.


i am asking if i can install .exe (GTA IV) on my ubuntu from 2  DVD ( using wine ), does it require any other programs ? Thanks.

I have tried playing GTA IV on PoL and Wine without luck. It works with every other game I have tried, including World of Tanks, Portal, Portal 2, Half-Life, BioShock, World of Warcraft,  Garry's mod and more. In my tests I installed the game and then applied the 1.0.7.0 patch. Now I cannot get it to boot, always crashes with the only error message being the playonlinux one.  I also tried with Wine, to no avail. Whole install works fine, then will not launch from the desktop shortcut or the /home/.wine/drive_c/program files(x86)/rockstar games/launchgtaiv.exe  It actually almost worked with update 3, but couldn't start the game or even change screen resolution. Changing wine version to the one recommended in the wine directory caused an error saying GTA IV needs a sound card to run. Changing sound driver is not an option because it says that there are none, but only with anything but wine ver. 1.3.23  My Specs:  CPU - AMD A10-6800K RAM - 4GB GPU -  9600GT (2007 version) (512MB DDR3) (Proprietary Drivers) HDD -  750GB hybrid drive


I would like to make my computer dual boot. I saw from Lenovo Setup utility that boot mode is UEFI so I need to make my bootable USB on GPT style. So how can I burn Windows 10 bootable usb on Ubuntu 20.04 with GPT style?

I'd like to create a Windows bootable USB stick, but I don't have a Windows machine with me at the moment to do so. How could I achieve the same using Ubuntu?


Here's the textbook problem I need to solve:  Write a recursive function that solves the following for a given number n:     The result I get for n = 6 is 120.184056 The result I want for n = 6 is 120.184052 The result I get for n = 7 is 720.147296 The result I want for n = 7 is 720.147339 My question is, why are my decimals off? The error seems to be increasing as I increase the n. My code: #include <stdio.h> #include <stdlib.h>  double factorial(int num) {     if(num==1)     {         return 1;     }     else     {         return num * factorial(num-1);     } }  double recurisve(int n, int c) {     double addend, enumerator;      if(c%2==1)     {         addend = c/2+1;         enumerator = factorial(n - c/2);     }     else if(c%2==0)     {         addend = n - (c-1)/2;         enumerator = factorial((c-1)/2+1);     }      if(c==n)     {         return addend + enumerator;     }     else     {         return addend + enumerator / recurisve(n, c+1);     } }  int main() {     int n;      scanf("%d",&n);      printf("%lf",recurisve(n,1));      return 0; }

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


I am using watchdog, a python package to monitor changes in the file system. The code works fine on Mac but it seems that the delete event is not monitored correctly in ubuntu. If I do a rm instead of move the file to trash, watchdog is able to detect the change. I am wondering whether there is a difference between moving to trash and rm command on the terminal in ubuntu that might lead to this behavior.  Thank you very much!

I read from a book where it says, the command rm deletes the inode and not the file. Which means if I delete with the rm command, then it cannot be restored.   I'm very new to Ubuntu environment. Now my doubt is, how does the Del key works? It is not deleting the inode as far as I am concerned, because I can restore it from my Trash folder. So am I right to say that Del  key is doing a mv command to Trash folder leaving the inode unchanged? Or am I missing something here?


I need to find a ,b real numbers such that polynomial $\P(x)=x^{4}-4 x^{3}+10 x^{2}+a x+b$ has 2 double roots. I have tried this $P^{\prime}(x)=4 x^{3}-12 x^{2}+20 x+a=0$ but I still have a so I cant find roots. I know I can write this polynomial as (x-A)^2*(x-B)^2 where A and B  are 2 double roots but I dont know how to proceed from here?

Given the polynomial $f = X^4 - 6X^3 + 13X^2 + aX + b$ you have to find the values of $a$ and $b$ such that $f$ has two double roots.  I went about this by writing the polynomial as: $$f = X^4 - 6X^3 + 13X^2 + aX + b = (X - r)^2(X - s)^2$$  ... and from there I arrived at a system of four equations from where I could find the desired values. However, there's quite a bit of work to do it this way; is there a shortcut?


I have made two activities. Main activity and  a second activity having a textview. My main activity is having a button and on button click i switch from this activity to other activity and just after that i call the method from main activity below the Intent part method named show() which changes the text of textview which is in second activity but as soon as i do so the application crashes.  03-23 01:33:44.791  26520-26520/com.dubey.abhishek.myapplication E/AndroidRuntime﹕ FATAL EXCEPTION: main     Process: com.dubey.abhishek.myapplication, PID: 26520     java.lang.NullPointerException             at com.dubey.abhishek.myapplication.Recipe.Showdetails(Recipe.java:43)             at com.dubey.abhishek.myapplication.MainActivity$1.onClick(MainActivity.java:54)             at android.view.View.performClick(View.java:4467)             at android.view.View$PerformClick.run(View.java:18776)             at android.os.Handler.handleCallback(Handler.java:808)             at android.os.Handler.dispatchMessage(Handler.java:103)             at android.os.Looper.loop(Looper.java:193)             at android.app.ActivityThread.main(ActivityThread.java:5292)             at java.lang.reflect.Method.invokeNative(Native Method)             at java.lang.reflect.Method.invoke(Method.java:515)             at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:828)             at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:644)             at dalvik.system.NativeStart.main(Native Method)

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


I have been looking at disassembled c recently (all compiled with gcc). I noticed every function begins with  push rbp  mov rbp, rsp   And ends with  pop rbp   Or the equivalent registers. I’ve heard this referee to as setting up a new stack for the function, but how does this actually benefit the code. Wouldn’t the code work exactly the same without it, as rbp can’t be accessed or chanced in c (without inline assembly) and pointers and variables are all offsets from rsp

I'm a beginner in assembly language and have noticed that the x86 code emitted by compilers usually keeps the frame pointer around even in release/optimized mode when it could use the EBP register for something else.  I understand why the frame pointer might make code easier to debug, and might be necessary if alloca() is called within a function.  However, x86 has very few registers and using two of them to hold the location of the stack frame when one would suffice just doesn't make sense to me.  Why is omitting the frame pointer considered a bad idea even in optimized/release builds?


I have a task to create a poll. The idea behind this poll is to be visible on a website, but without users. You dont need to be logged in user to answer the poll. However what I need is to make it so that after voting once you can't vote twice. This is something not really hard and something I have seen often in news sites.   The general solution for this is the cookie. You store information in the cookie and if they submit an answer you store that information in the cookie and you are all good.  However I want to do something even better - I want to make it so if you open Chrome and vote and then open Mozilla you wont be able to vote again.  The first thing that came to mind was using the IP, but then..what if you have multiple computers on one connection? Like in a big office building?  This means that I will need something that is unique to one specific computer no matter his internet connection.  What came to mind is to use something specific and unique to generate ID for the cookie. This means that by using something unique I will generate an ID which always will be the same for a specific computer, no matter the browser and no matter the connection. You can erase the cookie and then when I create new one it will be created with the same ID and I will be able to recognize that someone with that computer already voted for the poll.  My question is - what is unique to computers which I can access via the browser and how? I am using PHP with Symfony  and javascript for Front-end.  Again I will summarize what I want to achieve - some way to allow me to recognize a user (computer) without log-in even if that user deleted all cookies and switches browsers or is on different connections. He can use VPN or move from one country to another one and switch internet providers or anything of that sort...as long as he is on the same computer and that computer hasn't received braking changes (fixes, upgrades, etc.) I need to recognize it.

I need to figure out a way uniquely identify each computer which visits the web site I am creating. Does anybody have any advice on how to achieve this? Because i want the solution to work on all machines and all browsers (within reason) I am trying to create a solution using javascript. Cookies will not do. I need the ability to basically create a guid which is unique to a computer and repeatable, assuming no hardware changes have happened to the computer. Directions i am thinking of are getting the MAC of the network card and other information of this nature which will id the machine visiting the web site.


I need to make email validation on client side same with FILTER_VALIDATE_EMAIL. So what would be the equivalent regex on javascript with the FILTER_VALIDATE_EMAIL?  I found that FILTER_VALIDATE_EMAIL regex is from here:  but when I tried to copy paste the regex to javascript I get SyntaxError: Invalid regular expression: /#<error>/: Invalid group

Over the years I have slowly developed a  that validates MOST email addresses correctly, assuming they don't use an IP address as the server part.  I use it in several PHP programs, and it works most of the time.  However, from time to time I get contacted by someone that is having trouble with a site that uses it, and I end up having to make some adjustment (most recently I realized that I wasn't allowing 4-character TLDs).  What is the best regular expression you have or have seen for validating emails?  I've seen several solutions that use functions that use several shorter expressions, but I'd rather have one long complex expression in a simple function instead of several short expression in a more complex function.


What are the solutions in positive integers of the equation:  $${1+2^x+2^{2x+1}=y^2}$$ I tried to factorize the equation but it didn't help much. Clearly $y $ is an odd integer. Substituting $y =2n+1$, we get  $2^x+2^{2x+1}=(2n)\cdot{(2n+2)}$ $\Rightarrow (2^{x-2})\cdot(1+2^{x+1})=(n)\cdot(n+1)$ Which is the product of 2 consecutive integers. Does it help? I don't know.


What package is used to make slides like these:   It's two vertical slides at a time in a split screen format.

I found  presentation document by D. J. Bernstein. Is it possible to create it in latex?  Screenshot


I'm currently working on two research papers that I will send in a month to a peer-review journal, but I need to write my CV right now to apply for a job. In my CV there are currently three sections:  Refereed Journal Articles Refereed Conference Papers Other scientific publication [where I've included some non-refereed publications]  In your opinion, what is the best title for a section about the two papers I'm currently working on, which are going to be submitted to peer-review journals soon, but are currently in progress?

If I have works that are almost submitted to journals, or are in journal review, is it appropriate to include these on my CV?


Is there any measurable time dilation when Earth reaches perihelion? Can we measure such a phenomena relative to the motion of the outer planets?

What I mean is, the Earth orbits around the sun at around 30km/s, while I understand that this isn't a very high velocity does time dilation still occur to say a person who is completely stationary in space. And one last thing, the earth rotates at a higher velocity at the equator than at the poles, so would time dilation also occur there? So that people at the equator travel at a slower time relative to the poles? Again, I know that to see observable effects of time dilation you need to reach extremely high velocities and that these velocities would only result in a very tiny time dilation.


Failed to download repository information  W:GPG error: (http)://ppa.launchpad.net raring Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 464AD83D4631BBEA, W:Failed to fetch http://ppa.launchpad.net/bisigi/ppa/ubuntu/dists/saucy/main/binary-amd64/Packages  404  Not Found W:Failed to fetch http://ppa.launchpad.net/bisigi/ppa/ubuntu/dists/saucy/main/binary-i386/Packages  404  Not Found E:Some index files failed to download. They have been ignored, or old ones used instead.   I've try all the way from the question 'failed to download repository information'  thanks for the help

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


A leader should be selected by randomly choosing one of three parties A, B and C. The parties use the following protocol:   $A → B: N_A$ (where $N_A$ is a nonce)  $B → C:$ $N_{AB}$ $= N_A$ ^ $N_B$ (where $N_B$ is a nonce, and ^ is the ex-or operation}  $C → A:$ $N_{ABC}$ $= N_{AB}$ ^ $N_C$ (where $N_C$ is a nonce) ( Now both A and C know $N_{ABC}$)  $A → B$: $N_{ABC}$ (Now B knows $N_{ABC}$, too)  ( Each of the three parties can now compute $p = N_{ABC} mod 3$, where $p = 0$ denotes A, $p = 1$ denotes B, and $p = 2$ denotes C ).  Discuss the security of the protocol and establish if and how is it possible for some of the parties to deterministically choose the leader, being the others not aware of the fraud.  Then fix the protocol too.  I am training with security exercises, but I don't know how to approach to this. Can you give me some help?

Several people are playing a game with random events and require a way to produce a random number. (Such as dice rolls or a lottery.)  Can this be done such that each player has the power to be reasonably sure that the random number was fairly selected, without having to trust anyone else?  This question stems from a discussion in comments to my answer on the . I came up with a protocol but someone else spotted a flaw. This site seems more appropriate. Please feel free to make use of my answer to that question.


I killed Grelod the kind without talking to anyone from the brotherhood does this mean I cannot join?

I accidentally killed the orphanage lady before I started the quest. She just pissed me off, sadly it will not acknowledge that I have finished the quest and I haven't been contacted. Is there another way to join the Dark Brotherhood?


In leveling up the blacksmith, he will definitely craft some gear that is of no use to the monk (for example, a two-handed sword).  Does he eventually craft gear that is monk-specific?  Is it worth leveling the blacksmith to the point where such gear becomes available?

My blacksmith is at Level 3 (Adept) and I don't see fist weapons that I can craft.  Will be able to craft any fist weapons later? If so, what are the requirements?


Is there away to render update the objects that move while the back drop will be in scene? I have a huge scene setup it takes 3 to 4 mins per frame to render on the 1920 x 1080, I have learned many things to reduce render time while keeping good quality but in scene where camera doesn't move, only the character or car etc. I would like to render only updating the movement rather than doing whole picture but keeping the background in the render. When I have a good video editing software I know I can croma key characters etc. But would be nice to able to skip that process if possible.

I'm using an older Nvidia chip that hates running viewport renders, and I need to check if changes to the materials on a few objects not far from the center of my scene are (I'm rendering a floorplan with an orthographic camera from above, so I'm looking down on objects and want to check if the displacement materials are working correctly).  Is there any way to select a bit of the image and have it render first or without having to render the rest of the image? I'm aware that you can tell the image to render from an edge, but my stuff's about equidistant from either side of the scene.


I need to prove that $$\sum\limits_{k=0}^{n}2^k \binom{n}{k}=3^n$$  for any integer $n$. Induction seems to be the straightforward solution, but I have failed at it:  \begin{align} \sum\limits_{k=0}^{n}2^k \binom{n}{k}=\\\sum\limits_{k=0}^{n-1}2^k \binom{n}{k}+2^n=\\ \sum\limits_{k=0}^{n-1}2^k \binom{n-1}{k}\frac{n}{n-k}+2^n=\\ \sum\limits_{k=0}^{n-1}2^k \binom{n-1}{k}\left(1+\frac{k}{n-k}\right)+2^n=\\ 3^{n-1}\sum\limits_{k=0}^{n-1}2^k \binom{n-1}{k}\frac{k}{n-k}+2^n=\\ \end{align}  The last step is the induction hypothesis and the base of induction is trivial. I'm not sure what to do next.  There might also be a combinatorical proof: the expression on the left is the amount of ways to pick some balls out of $n$ balls and color each one of them in either of 2 colors. However, I do not follow how that is equal to $3^n$.

How can I show that the sum   $$ \sum_{k = 0}^n 2^k \binom{n}{k}$$  is equal to $3^n$?


I'm new in Java and I find it very complicated because of the errors that I come across with. So I have a problem with this piece of code:  Main Class:  public class Main {    public static void main(String[] args){       Answer a = new Answer();       String ans = null;       while(ans != "A"){          ans = a.create();          System.out.print(ans + "\n");       }    }  }   Answer class:  import java.util.Scanner;  public class Answer {    public String create(){      Scanner s = new Scanner(System.in);      return s.next();    }  }   I want the program to allow me to write something. Then, if what I've written hasn't been the letter A, the program must allow me to write something else, otherwise has to stop. But, even though I write "A", the program is still keeping on, allowing me to write something else. What's wrong with the code?

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


you have been hired by a gem mining company to develop a classification system that can classify gems as part of the automated sorting system.   you decided to use a network with one hidden layer. how would you go about determining the best number of hidden units to use in this layer

I have read  thread on how to select the appropriate number of hidden units and according to Introduction to Neural Networks for Java (second edition) by Jeff Heaton, one of the possibilities is - The number of hidden neurons should be between the size of the input layer and the size of the output layer.  However, I am trying to approximate some basic functions with neural networks in 3D space, having 2 inputs and 1 output, but if I choose only 2 hidden units, the approximation is not satisfaying at all. Only with more hidden neurons I get better results. Is there something I am missing?


Does it mean any day in a timeframe of 60 days max to the action, in other words: it could be 1 day or 59 days before?

I know that both can mean "inside" but what I don't have clear is whether both mean the same when talking about time. For example:   The party is in two days = The party is within two days ??   According to this link  within means a limit that can be exceeded, so I'm wondering too if say "the party is within two days max" is correct or redundant.


The render preview in cycles shows nothing but overlays. So I can see outlines, emptys, the camera... but not the actual objects, materials, light... .  When I render an image every thing seems right. Its is only the the viewport and it is not the clipping border. The problem is only in cycles, eevee works fine. I use Blender 2.83. Here is the . I am lost and can't work that way. Please, does someone know what to 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?


Why does mod(x,4) is 4 when x = {12, 24, 32}? should be 0, as in x = 4 and x = 8.   \documentclass{article} \usepackage[a4paper, total={6in, 9in}]{geometry} \usepackage{tikz} \usepackage{pgfplots} \pgfplotsset{compat=1.15}  \begin{document}  \begin{tikzpicture} \begin{axis}[ axis x line = middle, axis y line = left, style={draw=none}, xmin=-0, xmax=32, ymin=-1, ymax=6, width=15cm,height=10cm, ylabel=$y$, xtick={0,1,...,32}, %ytick=\empty, xlabel=t] \addplot+[const plot,samples at={0,1,...,32}] {(mod(x,4))}; \end{axis} \end{tikzpicture}  \end{document}

Am trying to align this in group of 3's but a bar in the AAAAAAAA group keeps going off alignment.   Note: I have checked  ,  and   and they don't answer my question - our data input format is different.  MWE:    \definecolor{bblue}{HTML}{82B1FF} \definecolor{rred}{HTML}{FF8A80}  \begin{filecontents}{testdata.csv} ALB,VAL,ERR,COR AA,20.61,0.32,bblue AA,20.88,0.55,bblue AA,20.41,0.29,bblue AAA,26.22,0.94,bblue AAA,26.43,0.45,bblue AAA,26.86,0.61,bblue AAAA,29.91,0.76,bblue AAAA,30.39,0.11,bblue AAAA,30.11,0.49,bblue AAAAA,34.71,0.43,rred AAAAA,34.87,0.99,rred AAAAA,34.81,0.26,rred AAAAAA,40.33,0.64,rred AAAAAA,40.18,0.03,rred AAAAAA,40.4,0.83,rred AAAAAAA,45.77,0.47,rred AAAAAAA,45.93,0.95,rred AAAAAAA,45.35,0.3,rred AAAAAAAA,50.35,0.13,rred AAAAAAAA,50.34,0.85,rred AAAAAAAA,50.66,0.55,rred \end{filecontents} \pgfplotstableread[col sep=comma]{testdata.csv}\datatable \makeatletter \pgfplotsset{     /pgfplots/flexible yticklabels from table/.code n args={3}{%         \pgfplotstableread[#3]{#1}\coordinate@table         \pgfplotstablegetcolumn{#2}\of{\coordinate@table}\to\pgfplots@yticklabels         \let\pgfplots@yticklabel=\pgfplots@user@ticklabel@list@y     } } \makeatother \begin{figure}  \begin{tikzpicture} \begin{axis}[     ylabel=A labels,  y label style={at={(-0.1,0.5)}},      y = -0.3cm,     ybar, %=2*\pgflinewidth,     draw opacity=0.5,     bar width=6pt,     enlarge y limits={abs=7pt},     xbar,      width=.36\textwidth,     xlabel= unit,     %flexible xticklabels from table={testdata.csv}{ALB}{col sep=comma},      flexible yticklabels from table={testdata.csv}{ALB}{col sep=comma},     yticklabel style={font=\small,xshift=0.5ex,  anchor=east},       %xtick=data     ytick=data,     xmajorgrids ] %\pgfplotsinvokeforeach {0}{     \addplot     %style={color=cyan,fill=bblue,mark=none};     plot [error bars/.cd, x dir=both,x explicit ]          table[y expr={(\coordindex) - mod(\coordindex,3)/8},x=VAL, x error=ERR ] {\datatable};  \end{axis}  \end{tikzpicture}  \end{figure}


Can anyone explain the difference between "macro" and "telephoto"?  I know that a macro lens will give you a magnification of 1:1 but how does it differ from a telephoto lens?

I've read a few threads on here that mention some  of macro lenses and found some marketing fluff in the box for my Canon about them as well, but being a complete novice I was left a bit confused.  Can someone please provide me with a top-to-bottom explanation of what a macro lens does?


Let $G$ be a Hausdorff topological group, let $F$ be a closed and let $K$ be compact, both subsets of $G$.  Then $FK$ is closed in $G$.      Attempt:  $aF$ is closed in $G$ for each $a \in G$.  All we have to do is show that $FK$ is compact since a compact subset of a Hausdorff space is closed.  $FK \subset \bigcup\limits_i U_i$

This could be classified as "homework", but I tried to solve this, made research online, and still failed, so I'll be glad to get some hints.  Let $G$ be a topological group, let $A$ be a compact subset of $G$, and let $B$ be a closed subset of $G$. Prove that $AB$ is closed.  If both $A$ and $B$ are not compact, but closed, this can fail, for example, if we let $A$ be the set of integers and $B$ the set of integer multiples of $\pi$, then both are closed, but $A+B$ is a proper dense subset of $\mathbb R$, so can't be closed. Also if $A$ is compact but $B$ is not closed, this easily fails.  Thanks


Unfortunately i delete my Document folder in Ubuntu 12.04 Desktop.  How to Recover the Document folder using commands...

Are there any tools, methods, incantations to recover recently deleted files on Ubuntu?  If it makes any difference, I want to recover a  2.x database file. But would be better to have a method/tool that works on any kind of file.


I ran these 2 commands simply in the terminal:  export PATH="$PATH:/home/milkncookiez/Developer/android-studio/bin" export PATH="$PATH:/home/milkncookiez/Developer/PhpStorm/bin"   in the 2 bin folders I have the files studio.sh and phpstorm.sh. In that same terminal session when I simply wrote the name of the files - the programs were ran.  When I opened another terminal - did not work. I added these both lines in the ~/.profile file, opened a new terminal session but it still does not work. How do I set the 2 variable changes to be permanent for all terminal sessions?

I want to add a directory to search my search path. I know I have to modify the PATH environment variable. However, I want the change to be permanent, so that it is always in effect, for every Terminal (bash) window I open.  There is an overload of confusing and possibly conflicting information in   I am using Ubuntu 10.04. Suppose I want to add /usr/local/foo to my PATH. Which file (.bashrc, .profile, .bash_login, etc...) should I modify and what should the new line(s) look like?


in 16 bit assembly you can use a 16 bit register like or use one of the 2 8 bit registers that comprise it why can you only use the high memory addresses in 32 and 64 bit assembly ?

%AX = (%AH + %AL)  So why not %EAX = (%SOME_REGISTER + %AX) for some register %SOME_REGISTER?


I must determine whether the following series converges: $$\sum_{n=1}^{\infty}\ln\left(n\sin\left(\frac{1}{n}\right)\right)$$  I know that in general, I must use the limit comparison test, but I cannot find an expression to which I can compare it. For instance, I have tried the usual process:  For $n$ large, we have that $\lim_{n\to \infty}n\sin\frac1n=1$, and so, $\ln(1)=0$. This fails the divergence test, but it cannot be concluded automatically that the series is convergent either. How may I proceed here? Any help would be appreciated.

Prove that $\displaystyle \sum_{n=1}^\infty \;\ln\left(n\sin\frac{1}{n}\right)$ converges.   My Work: $$\left|\ln \left(n \sin \frac{1}{n}\right)\right| \leq\left|\ln \left(n \sin \frac{1}{n^{2}}\right)\right| \leq\left|\ln \left(\sin \frac{1}{n^{2}}\right)\right|$$ I was going to use comparison test. But now stuck. Please give me a hint.


when I tried to print a small receipt I ran into the problem with print. all document display for print.when I click the print button.and after printed the document print button also printed on the page.i need to print receipt only on the page .i used window.print(); for print.

Pepsi Cola

                         Order #  &nbsp; &nbsp; 11111

                         Invoice   22344

                                     No	                                     Pname	                                     Qty	                                     Price	                                     Total

                                                                              1                                     	                                          Cake                                     	                                          2                                     	                                         120	                                         240

                         Sub Total &nbsp;&nbsp;240

                         Pay  &nbsp;&nbsp; 220

                         Due &nbsp;&nbsp;   20
                     <input style="padding:5px;" value="Print Document" type="button" onclick="myFunction()"></input>

   javascript

How do I print the indicated div (without manually disabling all other content on the page)?  I want to avoid a new preview dialog, so creating a new window with this content is not useful.  The page contains a couple of tables, one of them contains the div I want to print - the table is styled with visual styles for the web, that should not show in print.


A couple minutes ago I had a flag on a question. The question is now fine, but I can not reopen it, because I'm connected from the iOS app.  I can see only the reason that my question was flagged and a link how to write a question. Is there any reopen button?

Currently, when I want to reopen a question via my mobile device, I have to go to Safari or other browser app to do this.  Is it possible to add an option to vote to reopen via the app itself?


Here is the very elaborate, confusing, even befuddling image which I have selected at the time of this strange error occurring.

I want to enable GPU rendering, but there is no option in User Preferences > System:    Why is this? How can I get cycles to render using my GPU?


How can dark matter particles (WIMP's) get ever more densely clumped during the evolution of the universe, as we see for example in the Millennium simulation, if they can't loose kinetic energy by emitting radiation?

I understand that dark matter does not collapse into dense objects like stars apparently because it is non-interacting or radiating and thus cannot lose energy as it collapses. However why then does it form galactic halos? Isn't that also an example of gravitational collapse?


I am a new D&D player. I am just wondering if there is a maximum number of hit dice. In the PH, it says that you gain up to half of the maximum number of hit dice that you have. It is on page 186 under Long Rest. I can’t find anything else related to this. If you can help, it helps a lot. Thank you.

I am trying to fill in the "Alternative Character Sheet" (one of the ). It asks me for my "Maximum Hit Dice" and the "Remaining Hit Dice". What do these terms mean?


I am visiting Denmark for 4 months. I will need a mobile tariff with data for my Android phone. I won't be making many calls. Does any of the Danish providers offering a prepaid card with large data quota (at least 500 MB/month)? Or will I have to sign a contract?

Next month I am traveling to country X, where I would need Y minutes of calls, Z text messages and most importantly Q megabytes of data. How can I find the cheapest/most reliable SIM card for my needs?


I overstayed on a UK Visa (a couple of years) for personal reasons, then I've decided to leave voluntary, without telling them I'm leaving , I bought the ticket and left in 2018, I did check in, none of them told me anything, no immigration control, no passport check, no stamp nothing at all,  My question is :  Will they know I have overstayed? In the future will this bring me a problem to enter the UK?  How to check if I'm allowed or not to enter in the future?

I have a problem. I overstayed my uk tourist visa for about 10 months and decided to return voluntarily. However during my exit in February 2016, I did not meet any immigration officer at the Heathrow Terminal 3 before boarding the plane. I just went through the normal boarding process everyone went through without getting my passport stamped as an overstayer. Now I have gained admission to study a master's program in September in the uk and would like to make an application for a visa at the uk embassy In my home country. Is there any likelihood that the visa officer might know I overstayed my first visa even though nothing shows in my passport? Any help please? Thank you. Note my passport was never expired so it's the same passport I came back with.


I have upgraded to Ubuntu 14.04LTS from 13.10. Before upgrade sound was working fine, but after that its not working.Before trying below reference sound was working only through headphone but after below these  reference sound not working neither through headphone nor speakers(in-build). I tried solving from below reference link.    And i have attached logs for pulseaudio to the below reference link.    but after this sound icon always showing mute which was showing near battery icon, but when checked from system settings->sound->output volume its showing unmuted. I tried changing from mute to unmute from icon near battery icon but its not changing. And after playing videos its showing "An error occurred Could not initialize supporting library" error message is coming. Please suggest how to resolve this issue.

I have upgraded to Ubuntu 14.04LTS from 13.10. Before upgrade sound was working fine, but after that its not working. I tried solving this issue from a reference link     but still my problem is not resolved.


Sometimes I see code like this on Stackoverflow:   int main() { if(true){ return 0; } else{ return 1; } while(true){return -1;} }   I will usually suggest this edit:   int main() {     if(true){         return 0;     }     else{         return 1;     }     while(true){return -1;} }   I feel like not using spaces before and after brackets is OP's style, and should be respected. Indention however should be mandatory.  My edit was followed by another edit from a user:   int main() {     if(true)     {         return 0;     }     else {         return 1;     }     while(true) { return -1; } }   Should I've done this in the first place? I find it more readable the latter way, but OP may not be happy about it.  Of course it is nitpicking what I do now, but what about if the post is edited again in this way:   int main( ) {     if( true ) {         return 0;     } else {         return 1;     }     while( true ) {          return -1;     } }   Is this tolerable? My question is: should the formatting style be mimicked when editing posts? If so, what parts should be mimicked?

Some people like to put the open { bracket on a separated line, e.g:  if(...) {     //... }   Is editing this code by merging the first two lines into single one rude?


In a Ubuntu 14.04 server I am experiencing a massive hard disk activity which has no apparent justification: it comes as a burst, it lasts a few minutes and then disappears. It consumes system resources and slows down the whole system.  Is there a (command-line) tool which can be used to monitor the disk activity, listing the processes that are using the disk and the files involved? Something like htop for the CPU.

Occasionally, something on my system starts hammering the disk. I would like to log data that would let me know about I/O usage per process, then I could go back to it later and see what keeps doing this. How should I go about solving this problem? Bonus points for solving this for arbitrary block devices.


If I understand correctly, the words September, October, November and December all come from French counterpart Septembre, Octobre, Novembre and Decembre, and ultimately from Latin septem, octo, novem and decem with a suffix -bre. Therefore I suppose their original meaning were from "7th month of a year" to "10th month of a year".  Apparently those words stand for "9th month" to "12th month" nowadays, so why and how did this happen?

I'm not a native English speaker but I'm always trying to do my best. Unfortunately I have a real problem with dates for some odd reason, I couldn't learn when was my birthday until I was 12 years old.  Anyway, as I was learning names of the months on English, and since I know some Latin from high school I noticed that English months don't match up with their Latin numeral counterparts. For example:  September - 9. month October - 10. month November - 11. month December - 12. month  While on latin septem, octo, novem and decem are words for 7, 8, 9 and 10.  So, does anyone know why is that. At first I thought it had something to do with switch from Julian to Gregorian calendar but I figured it's too small of a difference.  Anyone? :)


I want to create an extension method that extends to all numeric types (int, ushort, double, etc). Extending IComparable does this, but it also extends the method to types where my function may not make sense (for example, clamping a char to a range between two characters). There isn't an interface just for numeric types, so I have to use IComparable. Is there a way for me to write my method so it'll only extend to the classes or structs I choose? For example, it will extend IComparable<float> and IComparable<int>, but not IComparable<char>. // Restricts an integer value to a range between min and max values. // This method works, but also extends to chars and other things it doesn't make sense for. static class Extensions {     public static T Clamp<T>(this T x, T min, T max) where T: IComparable<T> {         if(x.CompareTo(min) < 0) { return min; }         if(x.CompareTo(max) > 0) { return max; }         return x;     } }  Of course I could write an extension method for each type, or manually check with GetType() and throw an exception, or just accept that my function will clamp chars. But if I don't want to do those things, and if I don't work tirelessly to fix inconsequential non-issues, then I'm not a programmer.

Can anyone tell me if there is a way with generics to limit a generic type argument T to only:   Int16 Int32 Int64 UInt16 UInt32 UInt64   I'm aware of the where keyword, but can't find an interface for only these types,  Something like:  static bool IntegerFunction<T>(T value) where T : INumeric


I have an enterprise edition license for my Sql Server 2008R2 and want to know how many databases can I create on it without additional licensing costs  My question is not about number of databases that can i create on a single instance which is the case answered in several questions but databases without any additional costs. Please help me.  Thanks in advance

This is a  about Licensing.    Questions on licensing are off-topic on Server Fault.  If your question has been closed as a duplicate of this question, then this is because we want to help you understand why licence questions are off topic rather than just telling you "it just is". In all likelihood, this question will not address your question directly, it was not meant to.    I have a question regarding software licensing. Can the Server Fault community please help with the following:   How many licenses do I need? Is this licensing configuration valid? What CALs do I need to be properly licensed? Can I run this product in a virtual environment? Can I downgrade this product to an earlier version? Am I entitled to feature X with license Y?


I'm using format to test a function in Python.  I would like the output of a function   def test(f,k):     print "{0}({1})={2}".format(f,k,f(k))   given   test(Sqrt,4)   to be  Sqrt(4)=2   But format is giving back the type 'function' and a memory address inside angle braces.  Is there a neat way to shorten the output to get what I'm after?

In Python, how do I get a function name as a string, without calling the function?  def my_function():     pass  print get_function_name_as_string(my_function) # my_function is not in quotes   should output "my_function".  Is such function available in Python? If not, any ideas on how to implement get_function_name_as_string, in Python?


Let's say I have two lenses of 50mm, one with maximum aperture f/1.8 and another with f/1.4.   I understand that when using maximum aperture, for the latter lens more light will get to the film or photo sensor. That seems logical.  However, someone has told me that if in both lenses I will use f/1.8 aperture, still the latter lens will have more light. So, using same aperture shutter time will be still shorter for the latter lens. That sounds illogical to me.   Can you explain what makes lens brighter?

As an example, say you have two lenses:  300mm f/2.8 being used at f/8 300mm f/4 being used at f/8  My understanding is that by definition the amount of light coming through the aperture means that you will still have to take both shots at the same shutter speed (for the same exposure).  That said, why then pay for a lens that can work down to f/2.8 if, for example, you're going to use it regularly at f/8? (eg. at f/2.8 sometimes the depth of field can simply be too shallow - in the above example, take bird photography).  Some have told me the f/2.8 lens requires more glass to achieve f/2.8 and therefore it lets in more light and can shoot at a faster shutter speed at the same aperture - but I really don't think that makes sense.  The only other possibility that makes sense is that typically lens manufacturers will produce a better build quality on a lens that can achieve f/2.8, so, for example, you might get sharper images because of better build quality, but that has nothing to do with the lens' ability to stop to f/2.8.


Natural laws often feature squares and square roots, and second-order differential equations. Cubic laws, cube-roots, and third-order differentials are fairly rare.  (Some counter-examples: square-cube laws turn up when area/volume effects are scaled, and Stefan–Boltzmann law involves a fourth-power. Perhaps I'm just ignorant but I struggle to come up with many more.)  Is there a deep reason why higher-order effects would be rarer?

I mean, why is $F=ma$? Why not $m^{0.123}$, $a^{1.43}$ or some random non-integers or irrational?  I hope you understand that my question isn't limited just to force, energy, velocity, etc.; it also extends to the area of a square, circle, etc. and all other formulas.  I think the whole thing starts with direct proportionality.  Most of them tell about the area of a circle, $A = πr^2$, where π is 3.14159..... an irrational number! It's not about the constant. I am talking about the power of a physical quantity.  I know why it has pi. It's because we chose the constant for area square to be one. If we chose it to be 1 for the circle then the area of a square will have a constant, 1/pi.   I've edited the question to 'rational exponents' since all are giving me examples of decimal non-integers.


Webmaster tools show in "URL Errors" links to m/ and mobile/. My site have no active links to these URLs and they are not mentioned in sitemap.  Why google trying to access them?

I have a bog standard WordPress 4.2.1 site. I recently added it to Webmaster Tools and it is showing me URL errors (404s) that are linked from a weird URL: http://com.example.www/:http  (I have replaced my domain name with 'example'.)  There are two URL errors shown in Crawl > Crawl Errors > Smartphone:   mobile/ m/   When I click on either of this items, a popup appears telling me that Google could not crawl the page because it is non existent (which is true). When I click the Linked From tab, it shows that it is linked from http://com.example.www/:http  Where is this weird URL coming from?  EDIT:  The .htaccess is as follows:  # Begin default subdomain redirect # RewriteEngine on RewriteCond %{HTTP_HOST} ^example.co.uk RewriteRule ^(.*)$ http://www.example.co.uk/$1 [R=permanent,L]  RewriteCond %{HTTP_HOST} ^example.com RewriteRule ^(.*)$ http://www.example.com/$1 [R=permanent,L] # End default subdomain redirect #  # BEGIN WordPress <IfModule mod_rewrite.c> RewriteEngine On RewriteBase / RewriteRule ^index\.php$ - [L] RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule . /index.php [L] </IfModule> # END WordPress


I need to kill java process from a batch file I am using command  Wmic Path win32_process Where "CommandLine Like '%MyApp.jar%'" Call Terminate   I got the output at cmd "No Instance (s) Available"

Is there a command line utility that kills all processes with a specific command line?  E.g. kill all processes named "java.exe" with a command line that contains "-jar selenium-server.jar". This is possible through process explorer.


I keep getting a : java.lang.NullPointerException error message.  the: healthDamage(selectedCardOption.GetHealthAdjustment());  Then the error says "Null pointer access: The variable selectedCardOption can only be null at this location"  I guess I'm not sure why it keeps breaking the game. Also, where would I even add the option in to make it work?   I tried making a local variable field and it didn't work.   // Gather input from player   Integer input = scanner.nextInt();          // Showing Player Number They Selected         System.out.println("You've Selected Option: " + input.toString());         System.out.println("");          // Process Card Option         CardOption selectedCardOption = null;         for (int i = 0; i < card.getOptions().size(); i++) {             CardOption cardOption = card.getOptions().get(i);              if (cardOption.GetInput() == input) {                 selectedCardOption = cardOption;             }         }         // Only process if valid         if (selectedCardOption != null) {             if (selectedCardOption.GetIsExit()) {                 System.out.println("You've chosen to leave.. Thanks for playing!");                 running = false;             }         } else {             // Adjust Health and Skill based upon selection             healthDamage(selectedCardOption.GetHealthAdjustment());             System.out.println(                     "You've taken" + Integer.toString(selectedCardOption.GetHealthAdjustment()) + "Damage!");              skillIncrease(selectedCardOption.GetSkillAdjustment());             System.out.println(                     "You've added" + Integer.toString(selectedCardOption.GetSkillAdjustment()) + "this time");             // TODO: Logic to handle sub cards         }         if (selectedCardOption.getCards() != null && selectedCardOption.getCards().size() > 0) {             Random r = new Random();             int cardIndex = r.nextInt(selectedCardOption.getCards().size());             card = selectedCardOption.getCards().get(cardIndex);         }   The game is supposed to bring up a series of questions. It breaks upon starting.

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


I want to install Ubuntu/Lubuntu over the top of the C: drive where Windows 10 is now installed, removing it completely while preserving my data on the other partition doesn't gets formatted.  Is there any way to do that?   Thanks

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


We have a reputable news domain which is about 17 years old. We want to redirect this domain from example-all.tld to exampleall.tld. We will implement a 301 permanent redirect for all URLs.  Now traffic is coming from search on Google for the brand name and business keywords.  For these keywords we are first in the search results for pretty much all search engines.  We have many organic backlinks for example-all.com domain, Moz Domain Authority 64 & Page Authority 70.  When we redirect the domain, what types of SEO problems will befall the website? Will we get the same value of previous domain for backlinks, Google search, reputation, etc?  Is there any other method for this redirect from an SEO perspective?

As part of graduating from Area51 and becoming a full fledged site we sometimes change domain names from http://topic.stackexchange.com to http://example.com. Aside from the obvious 301 redirect rules to support existing urls transparently, are there other techniques that would aid in the preservation of SEO?


Can anyone help me out by suggesting any good software or any other way to increase downloading speed for files downloaded through firefox.

This question exists as it fills a specific criterion.  While you are encouraged to help maintain its answers, please understand that "big list" questions are not generally allowed on Ask Ubuntu and will likely be closed per the . More information on the .   What download managers are available for Ubuntu? Can you provide the link as well?


I don't know when I've started having this, but with my MacBook Air 2015 13", the volume icon only shows "Headphones" as an output device option.  The icon is not greyed out, nor is there any red light coming from the headphone jack. The startup chime works fine as well.   Resetting NVRAM - didn't work Resetting SCM - didn't work Re-plugging in the headphones (multiple times) - didn't work Twirling the headphone plug (multiple times) - didn't work Blowing in the headphone jack (multiple times) - didn't work

After plugging my headphones out, suddenly there is no sound from the internal speakers. When I press volume buttons, I see a circle-backslash symbol below the speaker icon.  Restarting doesn't help. However I do hear the startup chime. What should I do?


Related;   Could you cast Control Winds and direct it to be a gust towards say a dragon and counter the breath weapon? I find it hard that think that in the face of winds strong enough to cut one's movement in half that an exhaled attacks wouldn't just get blown back at the attacker.  The difference is that control winds is constant turbulence of wind as opposed to warding wind's simply circling the caster. This is a difference of a small barrier trying to counter a breathe weapon versus a constant force pushing in the opposite direction.  Am I missing something about the breath weapon? Does magic simply hold a red dragon's flames in that 15 foot cone in spite of the gale blowing in the opposite direction?   Counter to the answer given; We are talking about gale force winds countering a directional breath attack. Which consist of; fire, lightning, acid, poison gas, and cold AIR! The only one I can logically see not being effected too much by strong opposing winds is the lightning. Everything else by common sense should be pushed aside by winds traveling over 40mph/60kpm. So I ask, does the spell description lacking stating such bypass common sense?

Potential combat with a Green Dragon. The most damaging item in a Green Dragon's arsenal is its Poison Breath. The text of poison breath is some variant of this for Green Dragons:     The dragon exhales poisonous gas in a xxx-foot cone. Each creature in that area must make a DC YY Constitution saving throw, taking ZZ (AAd6) poison damage on a failed save, or half as much damage on a successful one.   The text of Warding Wind states that one of its effects is:     It hedges out vapor, gas, and fog that can be dispersed by strong wind.   Can this effect stop the Poison Breath from getting into the creatures within the Warding Wind Spell?


I'm just completely lost, how does movement and attacking work? And what about battles with people and monsters moving around?

Our target play style for combat encounters would be to use battle boards roughly half the time (when there is enough of interest in play that the tactics are fun to play out), and to skip that with faster "cinematic" combat otherwise.  We have not been 100% successful. The problem is the numbers-driven descriptions in the rules. Needing to be "adjacent" (within 5 feet) for abilities such as Protection style fighting, ranged weapon ranges, spell effects and movement speeds are all much easier to resolve on a grid. Running those rules without a board rapidly devolves into sketches with numbers written on them and/or "mother, may I?" style of play because the DM needs to rule who is next to who, and which monsters are in the spell radius. These rulings also quickly get out of sync with player expectations when there is no map and we want to run combats quickly.  It doesn't help that the numbers involved come in pretty much all multiples of the base 5 feet. There is no obvious close/short/medium for effects and ranges. If there were such then I think it would be much easier for the DM to categorise and hand-wave things.  I was hoping that both board-based and no-board style of play would feel equally viable. But the focus on numbers seems to push toward board playing, at least for my group.  We would still like to pay heed to the differences in movement, range, area-of-effect etc of the rules in play. At least in the general sense of creature X is faster than creature Y, or weapon/spell A has better range than weapon/spell B.  Going beyond "just don't sweat the details", how can a group like mine play with the D&D 5e rules as written, without a map, but without leaning on the DM to resolve all our questions of "So, am I next to the Paladin?", or "Is it in range?"      Clarifying: "just don't sweat the details" is a welcome approach to solving the problem, but please give some examples of how this works in practice; i.e. which details can be removed and how?


I have a directory that is set up as \server\\year\month\day\x, .../y and .../z. I need a batch file that will delete videos located in the x folder in each user's directory for each month day and year based on a retention period (IE 60 days). Then delete the files in Y based on a different period (IE 730 days)  I have forfiles -p "\\server\username\year\month\day\x" -s -m *.* -d -60 -c "cmd /c del @path" but I am not sure how to do the loop in the path to search all of the sub directories from the network folder to find only the X folders.   Is there a way to do this without using the created on date attribute, just in case the camera's date/time was incorrect when the video was taken. Thanks in advance for the help! (If anyone knows a syntax that I could research I would greatly appreciate it)

I am having issues making this syntax work correctly. What I would like to do is remove all tmp and bak files from the specified directory and all subdirectories if the modified date is older than 7 days.  for %G in (.tmp, .bak) do forfiles -p "C:\test\cad projects" -s -m *%G -d -7 -c "cmd /c del @path"   My syntax was gathered from .  If I change my search mask to only include one desired extension then I get correct results.  forfiles -p "c:\test\cad projects" -s -m *.bak -d -7 -c "cmd /c del @path"   I don't do much with batch files so I was hoping someone could assist. Thanks for reading.


I want to receive my javascript object such as   { "user": { "active": true,  "dob": '1988-09-11', "group": 14, "department: "business"" } }   from input using a node package such as readline-sync and store it as an object to be able to access to the values seperately using their keys. The readline-sync stores my input as an string I tried to convert it to javascript object using   let obj= JSON.parse(JSON.stringify(stringObj));   but still it is string.  Is it possible to receive a string from the input and convert it object?

Given a string of JSON data, how can I safely turn that string into a JavaScript object?  Obviously I can do this unsafely with something like:  var obj = eval("(" + json + ')');   but that leaves me vulnerable to the JSON string containing other code, which it seems very dangerous to simply eval.


I have used a random forest model for regression analysis. Now, I am having difficulty in working out what can be used in measuring variable importance.  The importance function provides the mean decrease in accuracy and the mean decrease in MSE.   the question is:  why the absolute value of importance is not very helpful and how to build relative importance values.

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


I am trying to get an animation that has 3 render layers to have a transparent background.  How would I do this?  Simply checking the transparent box under film does not work with multiple layers  Thanks for any help.  (Cycles)

This is what I have so far:  The rendered image has a transparent background, but the glare filter creates an output with a black background, so after merging the two togheter, the background turns black but I need it to be transparent, what can I do?


I am looking for a LaTeX editor that can manage Hebrew and RTL, and that is supported on OSX, I came across many but did not find that works. Thanks

What editors/IDEs are available for easing the process of writing TeX/LaTeX documents? Please state some useful features like code completion, spell checking, building final DVI or PDF files, etc.  This question is undergoing a systematic refurbishment, see  on Meta. If you’d like to see another editor feature covered here or to take care of an editor that’s not covered yet, share your ideas in that meta question.  List of editors Links to answers.


If you see the  and total user rep, then the first thing that pops up is:    Obviously, the person only has 27K total rep.

My Area51 site proposal, , just got into commitment phase two days ago. Why does it show that I have 69K reputation, when I actually have 9.7K?


The PC is recognising my HP printer but I am still unable to print. I have tried both the methods (Method 1 and 2) mentioned in this , but it is still not working. The terminal didn't complete installation by method 2, I waited for 4-5 hours hoping it will complete but it didn't. Please help me find a solution

Let's assume that one has some modern HP printer and/or scanner which is  supported by HPLIP package from official repository. Or supported by newer version of HPLIP package (see  about installation).  From official documentation () it is known that device needs proprietary/binary driver or plugin.  How should one install such plugin?


How can I check whether a particular button was clicked or not in ASP.NET?  I think I need to perform some operation on Page_Load. This shouldn't be entering to Button_Click event to find. Is there any way that I can find where it was clicked or not on Client Side and take it to Page_Load?

In c#, how can I check to see if a link button has been clicked in the page load method?   I need to know if it was clicked before the click event is fired.


If organisms can carry DNA with 6 bases which supposedly stores increased genetic information, why living organisms evolved to have DNA made of 4 bases and not 6 or other number? is there any theory about this, were the chemical process to reach those 2 additional bases much more complex or something?

In short  Looking at the genetic code, it appears that most redundancy is on the third letter rather than on the first or the second letter of the codon. Why has it evolved this way?    Longer version  In order to compare the relative redundancy accounted by each letter of the codon, let's assume that that every codon occurs at equal frequency. It is probably wrong but useful for the sake of the calculations. Using observed frequencies of codon usage in a given population would change the following probabilities but the question of why some positions in the codon has more redundancy than some others still hold.  A substitution of the first letter of the codon has a probability of $\frac{1}{2048}≈0.00005$ (Stop codon) to be synonymous. A substitution of the second letter of the codon has a probability $\frac{3}{256}≈0.012$ (nucleobases U and G) to be synonymous. A substitution of the third letter has a probability of exactly $\frac{2}{3}$ to be synonymous.  Probability of a substitution to be synonymous given that it occurred on the...   First letter: $\frac{1}{2048}≈0.00005$ Second letter: $\frac{3}{256}≈0.012$ Third letter: $\frac{2}{3}$   Why are there more redundancy on the third position than on the second (which has more redundancy than the first position) in the codon?


The below is a snippet that updates a customers name using SQL*Plus. It works ok for all customers except for customers whose name contains a '&' symbol even though the name is 'enclosed'.   sqlplus -s $user/$pass@$db << EOF UPDATE order_address SET name = '$customer_name' WHERE address_type = '2' AND order_number = '$order_number'; COMMIT; EXIT; EOF   What should be done so that it works even on customers whose name contains a '&'?  Update: It seems it does actually work but wherever there is a '&' it puts 'COMMIT;' so the name shows as 'A COMMIT; B' instead of 'A & B'.

I have a SQL script that creates a package with a comment containing an ampersand (&). When I run the script from SQL Plus, I am prompted to enter a substitute value for the string starting with &. How do I disable this feature so that SQL Plus ignores the ampersand?


The Stack Exchange Android app hasn't been working for me for half a year. I only still have it for the notifications.  Even after reinstalling, notifications are the only feature that works. When I start the app, it only loads for some time and then shows a loading error. No home page, no notification drawer.  I also see that it's last been updated in 2017. Have they been working on a PWA the last two years or what?  I'm using an HTC one M9 with Android 7.1.

It's been a while since the Stack Exchange team last had an iOS or Android developer, and the development job on the apps have not had any insights for years.  That, however, doesn't deny the fact that there are still many users to them. As a consequence, people are continuing to submit bug reports and sometimes feature requests about them.  If development on iOS/Android apps has ceased indefinitely, what should we do to their bug reports and feature requests?  Are we going to keep them with the hope that development on apps will resurrect one day, or just ignore them and telling users that development has frozen?


For example, 'foo bar' would be quoted as `foo bar', or ``foo bar''. Is it encouraged or general practice to use this quoting syntax? It seems to be quite common in some documentation.

I've noticed that man pages and other documents formatted by Unix utilities often use double backticks `` followed by double single quotes '' to wrap quoted phrases instead of the double quote character ". Single quotes are similarly replaced. Why is this?  Here are a couple examples, from the man page for grep:   To find all occurrences of the pattern `.Pp' at the beginning of a line:         $ grep '^\.Pp' myfile   The apostrophes ensure the entire expression is evaluated by grep instead  of by the user's shell.  The caret `^' matches the null string at the  beginning of a line, and the `\' escapes the `.', which would otherwise match  any character.   The grep utility is compliant with the IEEE Std 1003.1-2008 (``POSIX.1'')  specification.


Take WinDbg for example. By default it installs into C:\Program Files (x86)\Windows Kits\10\Debuggers\x86\windbg.exe (and x64), which means there are two executables with the same name.  How can I put both of those in my path under different names, so that I can pick which one I'm launching?

I added addresses of python 2.7, and Anaconda 4.1.1(Python 3.5) to PATH variable in Windows 10, whenever I run "python" from cmd, program which was added earlier is executed.How can I access both of them depending on my choice without altering name of either


I have this page:    I want my div .container-home to be align vertically to the center.  CODE HTML:

   How do I do this?  I found these examples but we did not implement them.    Thanks in advance!  EDIT:  I add:  body{display table;} .container-home{display:table-cell;vertical-align;middle;}   but not working.

I want to center a div vertically with CSS. I don't want tables or JavaScript, but only pure CSS. I found some solutions, but all of them are missing Internet Explorer 6 support.
Div to be aligned vertically
   How can I center a div vertically in all major browsers, including Internet Explorer 6?


I came across this construct while reviewing some older unix shell scripts, what does it mean, and why is is used?  ${1+"$@"}

I've noticed that sometimes wrapper scripts will use ${1:+"$@"} for the parameters rather than just "$@".  For example,  uses  exec "$binary" $opts ${1:+"$@"}   Can anyone break ${1:+"$@"} down into English and explain why it would be an advantage over plain "$@"?


I will be giving an introduction to Historians or introduction of Historians. Which one is correct? 'to' or 'of'?

What exactly is the difference between "introduction to" and "introduction of"?  For example: should it be "Introduction to the problem" or "Introduction of the problem"?


OALL8 issue occurs while deploying an application on JBoss 6.1 EAP.  Here is the stacktrace:     java.sql.SQLException: OALL8 is in an inconsistent state at   oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112)   at   oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:146)   at   oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:208)   at oracle.jdbc.driver.T4C8Oall.marshal(T4C8Oall.java:352) at   oracle.jdbc.driver.T4CPreparedStatement.doOall8(T4CPreparedStatement.java:199)   I am using racojdbc14.jar to connect to the oracle database.   Oracle Database: Oracle 11g. It is an RAC Cluster  Can anyone please post the solution to resolve this issue?

As part of upgrading JRun, we are moving from a 1.4 JVM to a 1.6 JVM. Now I am getting a really strange oracle db error: "OALL8 is in an inconsistent state". I have pinned down the problem to insert queries that do not use bind variables at all - all inline parameters. If I run the query without any bind variables, I get the above error. As soon as I replace one of the hard coded values with a bind variable - everything works without error.  The other strange bit is that after executing the query, it is in fact committed to the database. I can connect from another session and see the inserted row. I have tried wrapping the query in a transaction and it seems to succeed as the behavior is unchanged from the query without an explicit transaction.  Here are the relevant details:  Java Version: 1.6.0_12-b04 Virtual Machine Version: 11.2-b01 (HotSpot Server) Oracle Server: 10.2.0.4 Oracle Client: 11.1.0.7.0 through ojdbc6.jar    Update: I am using cfqueryparam - they are called bind variables in the oracle world. While that does solve the immediate problem, we have a rather large legacy code base that we can't realistically go through all of to update the queries as part of upgrading from CF7 to CF8.  Even though I have pinned down one specific situation that fails (and encapsulated it in an mxunit test) - that doesn't mean there aren't other areas where this may be an issue. I would really like to have a solution in place that removes the OALL8 error rather than coding around it.  Update 2: After checking with our DBA he had set a parameter called CURSOR_SHARING to SIMILAR. The Oracle default is EXACT. What is happening is when ColdFusion hands the query off to be executed, Oracle is turning all the literal values to bind variables and that appears to be confusing ColdFusion. Turning the setting back to EXACT allows the literal queries to work just fine.  Update 3: Oracle finally issued us an out-of-band patch for JDBC. It was identified as a JDBC error. The latest drivers should include it when they are finally updated. If you have support you can also request the patch through their TAR system.


By definition, if $A$ is a $ n \times n $ matrix, an inverse of $A$ is an $ n \times n $ matrix $A^{-1}$ with the property that:  $$ A^{-1}A=\mathbb I_n \ \ \land \ \ AA^{-1}=\mathbb I_n \ \ \ \ (1)$$   where $ \mathbb I_n $ is the $ n \times n $ identity matrix.  Are there any cases where $ A^{-1}A=\mathbb I_n$ but $AA^{-1} \neq \mathbb I_n$ or the other way around (and thus making (1) a false statement) ?

If $A$ and $B$ are square matrices such that $AB = I$, where $I$ is the identity matrix, show that $BA = I$.    I do not understand anything more than the following.   Elementary row operations. Linear dependence. Row reduced forms and their relations with the original matrix.   If the entries of the matrix are not from a mathematical structure which supports commutativity, what can we say about this problem?  P.S.: Please avoid using the transpose and/or inverse of a matrix.


I have an abstract class say CTest which contains only the abstract method f1() and nothing else. Similiarly, i have a Interface ITest with the only method f1(). Here both the CTest abstract class and ITest interface does the same thing.   The one difference is that, the Interface provides the flexibility that it can be implemented in any classes which already derived from other class but abstract classes cannot.   Apart from the above difference, What is the actual difference between these two? and which one is efficient here(CTest or ITest)? When i should use what? Any specific scenario's in OO Design and any general suggessions on this are helpful

This may be a generic OOP question. I wanted to do a generic comparison between an interface and an abstract class on the basis of their usage.   When would one want to use an interface and when would one want to use an abstract class?


Let's say I have 2 account, account A & B. I don't want to use account A anymore, yet I still want to retain all the files. I want to move account A's belongings to account B. How do I do that?

Some time ago, when I installed Ubuntu, I chose a rather stupid username for my account that I do not want to use anymore. How do I change this (including the name of my home directory, and the name in the terminal) without losing settings for applications? How do I keep permissions and my keys for various authentification (e.g. email, SSH, GPG and more)? What settings could possibly get lost if I changed my username?


What I am trying to do is set up one script that will check the ratio of height over width and then determine WHICH dimension to scale to fit HD(1920x1080). Is this possible using standard FFMPEG commands?  I also need to crop either height or width if the resulting dimension is larger than 1080 or 1920 respectively.  I've already read this   so i know how to scale if you know in advance WHICH dimension of your source video is larger.

I have a html 5 video player which is 700px wide, 400px high. I'm trying to use avconv to use ffmpeg to resize (while retaining the aspect ratio) and making sure it fits into my player.  Input can be a file of any size, so I need to resize the larger ones but center the smaller ones with black bars. So far I've tried: -s and -aspect, I've seen pad being used with the -vf switch but don't understand how it works enough to get what I need.    This is a rough idea of what I need. I'm not sure if it's even possible. It's almost like CSS's max-width/max-height. I realise this may just be a jumble of words but if anyone happens to understand what I'm talking about, I'd appreciate help, Thanks.  avconv command:  avconv -y -i control.avi -vcodec libx264 -b 2000k -bufsize 20M -acodec aac -strict experimental -ar 44100 -ab 256k bigbuck_out.mp4


How can I convert underscore separated words to "camelCase"? Here is what I'm trying:  echo "remote_available_packages" | sed -r 's/([a-z]+)_([a-z])([a-z]+)/\1\U\2\L\3/'   But it returns remoteAvailable_packages without changing the p in packages.

If I have a string that looks like this:  "this_is_the_string"   Inside a bash script, I would like to convert it to PascalCase, ie UpperCamelCase to look like this:  "ThisIsTheString"   I found that converting to lowerCamelCase can be done like this:  "this_is_the_string" | sed -r 's/([a-z]+)_([a-z])([a-z]+)/\1\U\2\L\3/'   Unfortunately I am not familiar enough with regexes to modify this.


I think that logically, I understand the concept because no matter what polynomial you have you can always factor it into something with a x to a power plus or minus some real number, and that real number can be a fraction, or an irrational number, or a whole number. However, I am not sure how to write this in a reasonable mathematical way.

I want to prove that every real polynomial of odd degree has at least one real root, using  the intermediate value theorem.  Let $P(x) = x^{2n+1} + a_n x^{2n} + . . . + a_0$ for each $a_i \in \mathbb{R}$ and $n \in \mathbb{N}$.  By the fundamental theorem of algebra I know that $P(x)$ has exactly $2n+1$ complex roots, so  $P(x) = (x+r_1)(x+r_2) . . . (x+r_{2n+1})$ for each $r_i \in \mathbb{C}$  I do not know how to complete this but I do know that, at some point, I probably have to show that each root with imaginary part non zero has to come in conjugate pairs, and since $2n+1$ is odd there is at least $1$ root that is imaginary part $0$ and thus real.


Whenever a foreign particle enters into someone's body, it is attacked by the white blood cells. I just want how it is that, when sperms enter the female body, they are not attacked by the the woman's immune system?

Why do the white blood cells allow foreign bodies like sperm to exist inside body cavity without any reaction?   White blood cells function is to fight against foreign bodies (from the text books).


I want to create my own protocol "openect://" and use it to navigate across an archive.  using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Diagnostics;  namespace ConsoleApp91 {     class Program     {         static void Main(string[] args)         {             Process.Start(@"openect://www.archive.com/chair.jpeg");         }     } }

I have seen:   http://www... ftp://blah.blah... file://blah.blah... unreal://blah.blah... mailto://blah.blah...   What is that first section where you see http and the like called?  Can I register my own?


I want to create a select option in Razor pages from Enum object Description This is my code: <div class="dropdown-box">     <select id="type-select">         @foreach (var item in Enums.OrderStatus)         {             <option>@item</option>         }     </select> </div>  and the enum: public enum OrderStatus {     [Description("در انتظار تایید")]     PendingForAccept = 0,      [Description("تمام شده")]     Finished = 1,      [Description("لغو شده")]     Canceled = 2,      [Description("رد شده")]     Rejected = 3,      [Description("تایید شده")]     Accepted = 4 }  How can I extract items descriptions of this enum to string

I have the following enumeration:  public enum AuthenticationMethod {     FORMS = 1,     WINDOWSAUTHENTICATION = 2,     SINGLESIGNON = 3 }   The problem however is that I need the word "FORMS" when I ask for AuthenticationMethod.FORMS and not the id 1.  I have found the following solution for this problem ():  First I need to create a custom attribute called "StringValue":  public class StringValue : System.Attribute {     private readonly string _value;      public StringValue(string value)     {         _value = value;     }      public string Value     {         get { return _value; }     }  }   Then I can add this attribute to my enumerator:  public enum AuthenticationMethod {     [StringValue("FORMS")]     FORMS = 1,     [StringValue("WINDOWS")]     WINDOWSAUTHENTICATION = 2,     [StringValue("SSO")]     SINGLESIGNON = 3 }   And of course I need something to retrieve that StringValue:  public static class StringEnum {     public static string GetStringValue(Enum value)     {         string output = null;         Type type = value.GetType();          //Check first in our cached results...          //Look for our 'StringValueAttribute'           //in the field's custom attributes          FieldInfo fi = type.GetField(value.ToString());         StringValue[] attrs =            fi.GetCustomAttributes(typeof(StringValue),                                    false) as StringValue[];         if (attrs.Length > 0)         {             output = attrs[0].Value;         }          return output;     } }   Good now I've got the tools to get a string value for an enumerator. I can then use it like this:  string valueOfAuthenticationMethod = StringEnum.GetStringValue(AuthenticationMethod.FORMS);   Okay now all of these work like a charm but I find it a whole lot of work. I was wondering if there is a better solution for this.  I also tried something with a dictionary and static properties but that wasn't better either.


I tried to install python3 using these commands.  1. python3 -V 2 sudo apt-get install idle-python3.4   But however after installed python3 I just wanted to remove what I installed, so I unstalled python. Now my computer's GUI has been removed. How do I recover Ubuntu?

I am a new Ubuntu user running Ubuntu 13.04.  I've been trying to install and use a DeDRM tool, but I've been having problems doing so. I was following some directions that said I needed a version of Python 2.7, but not anything Python 3.0 or later (because 3.0 versions are missing some necessary libraries?). I tried to install Python 2.7.5.6, but it didn't work. I thought it was probably because I had the later version of Python, so I went through terminal and removed Python 3.3, so I could install the earlier version of Python.  Now that I've uninstalled Python 3.3, a lot of applications no longer work, including the terminal and the Ubuntu Software Center. I have no idea how to fix this problem now.