I have a List<Animal> , which contains 100s of objects. There'll be a field which is AnimalType that will be common. I need to fetch  this value.              List<Animal> foundAnimal = db.Animals                 .Where(a => a.Name == "Elephant"                     )).ToList();   The foundAnimal object has a element called AnimalType (Which is an int) which is the same for all "Elephants". I need to retrieve this value from the above List.   How can I do that ?  Animal object  private string Name {get;set} private int Age{get;set} private int AnimalType{get;set}   What I tried:  var ani = foundAnimal.Distinct();   But the above gives me a list of Distinct Animal objects. What I need to know is the value that is common in the Animal Object (for the name Elephant)  which is a int value.  UPDATE  new Animal {Name = "Elephant" , Age 12 , AnimalType = 1 }  new Animal {Name = "Elephant" , Age 12 , AnimalType = 1 }  new Animal {Name = "Elephant" , Age 12 , AnimalType = 1 }  new Animal {Name = "Ant" , Age 12 , AnimalType = 2 }  new Animal {Name = "Ant" , Age 12 , AnimalType = 2 }  new Animal {Name = "Elephant" , Age 12 , AnimalType = 1 }  new Animal {Name = "Elephant" , Age 12 , AnimalType = 1 }  new Animal {Name = "Elephant" , Age 12 , AnimalType = 1 }    The list will give me Animals where Name is Elephant  List<Animal> foundAnimal = db.Animals             .Where(a => a.Name == "Elephant"                 )).ToList();   The above Will return Only Objects where the Name is equal to Elephant.  All what I need is to get the AnimalType which is 1 when Name == Elephant.   Hope I was able to explain this clearly.

I am playing with LINQ to learn about it, but I can't figure out how to use Distinct when I do not have a simple list (a simple list of integers is pretty easy to do, this is not the question). What I if want to use  on a list of an Object on one or more properties of the object?  Example: If an object is Person, with Property Id. How can I get all Person and use Distinct on them with the property Id of the object?  Person1: Id=1, Name="Test1" Person2: Id=1, Name="Test1" Person3: Id=2, Name="Test2"   How can I get just Person1 and Person3? Is that possible?  If it's not possible with LINQ, what would be the best way to have a list of Person depending on some of its properties in .NET 3.5?


I am working with some real estate data on housing units. For a given market, I have data on occupied units, rents, and control variables such as population, demographics, income levels etc. I'd like to obtain the diminishing marginal effect and the elasticity estimate. i.e the point at which rents have a diminishing effect on occupied units. I attempted to do this using ols - log-log regression, I need non-linear model to fit the data. import statsmodels.formula.api as sm  model1 = sm.ols(formula = 'np.log(Occupied_units) ~ np.log(Rent) + np.log(Income) + np.log(unemployment)', data=df).fit()  My question is, what non-linear models can I use to estimate this diminishing effect? and how do I interpret the results? i.e the point at which the effect starts to diminish.

I am working on an price optimization problem for a Real Estate company. Basically, we'd like to optimize their rental price to maximize revenue on their properties. I have submarket level data such as rental price, occupancy rate, comparable units, operating expenses (fixed cost) in the market, etc. So for a given set of prices p = {40....60}, the objective is to find the optimal price point i.e the point where marginal revenue => marginal cost. The first answer on this question is one of way of doing it, however, I may not always have probability distribution and the relationship between price and predicted occupancy is non linear:  Simple Linear: 𝑝𝑟𝑖𝑐𝑒(𝑠𝑖)=𝑏+𝑐×𝑝(𝑠𝑖) where 𝑐 is a scaling constant. Implies that price and probability are linearly related.   I have attempted to use log-log regression to calculate elasticities: import statsmodels.formula.api as sm  mod = sm.ols(formula = 'np.log(Occupancy) ~ np.log(Rent) + np.log(Income) + np.log(unemp) + np.log(comparable)', data=df).fit()  mod.summary()   The regression above fits price and economic control variables on occupancy rates. With R-Square of 0.94, I am suspicious of this model and there is likely an endogeneity problem. What non-linear methods can I fit to find the optimal rental price. Open to any other ideas/suggestions as well.


I understand a proton is made up of quarks/gluons. I want to know if a proton has an actual core? Also whether protons have a core/surface temperature.

What constitutes protons? When I see pictures, I can't understand. Protons are made of quarks, but some say that they are made of 99% empty space. Also, in this illustration from Wikipedia, what's between the quarks?


I have written these lines in a file  AA BB CC   With the following python code  f = open("foo.txt",'r') for line in f:     print (line)   I see that there is a newline between each line that is reads from  AA  BB  CC  # terminal prompt   How can I remove those new lines?

I'd like to do it in Python. What I'd like to do in this example in C: #include <stdio.h>  int main() {     int i;     for (i=0; i<10; i++) printf(".");     return 0; }  Output: ..........  In Python: >>> for i in range(10): print('.') . . . . . . . . . . >>> print('.', '.', '.', '.', '.', '.', '.', '.', '.', '.') . . . . . . . . . .  In Python print will add a \n or space, how can I avoid that? Now, it's just an example, don't tell me I can first build a string then print it. I'd like to know how to "append" strings to stdout.


I solved the following exercise:  Find an integer $n$ such that $U(n)$ contains a subgroup isomorphic to $\mathbb Z_5 \oplus \mathbb Z_5$.  Here $U(n)$ is the group of units modulo $n$.   To solve it I used that $U(st) = U(s) \oplus U(t)$ when $s,t$ are coprime and $U(p^n) = \mathbb Z_{p^n - p^{n-1}}$. I tried the first few primes until I found two with the property that $\mathbb Z_{p^n - p^{n-1}}$ is divisible by $5$.   My result:  $$ U(3025) = U(5^2 \cdot 11^2) = \mathbb Z_{20}\oplus \mathbb Z_{110}$$  It seemed clear to me that I had found the smallest number with this property since I chose the first primes I found. Then I looked at the solution which is  $$ n =275$$     What other methods are there to solve this question so that I can find   the smallest such $n$?   Obviously, while possibly correct, my method does not find the smallest $n$.

Let $U(n)$ to be the set of all positive integers less then $n$ and relatively prime to $n$. Then $U(n)$ is a group under multiplication modulo $n$.  A. Find integer $n$ such that $U(n)$ contains subgroup isomorphic to $Z_5\oplus Z_5$.  B. Show that there is an $U(n)$ containing a subgroup isomorphic to $Z_3 \oplus  Z_3$, but not isomorphic to $Z_4 \oplus  Z_4$.


It is a common practice, people calling and writing Tony for Anthony, Mike for  Michael, Max for Maxwell etc. It is correct to write or call ? I mean Anthony and tony can be two different names. Why confusing then?

Why is Robert called Bob and John called Jack sometimes? What is the history of or reason for this practice in changing the English names of people?


I've been trying to think up of two combinatorial proofs but I'm confused on the first and just completely stuck on where to begin for the second.   $$\sum_{k=-m}^n \binom{m+k}{r}\binom{n-k}{s} = \binom{m+n+1}{r+s+1}$$ For the RHS, I understand that it is basically looking at the number of $(r+s+1)$ subsets that can be formed from $(m+n+1)$. On expanding the LHS to yield $\binom{0}{r}\binom{n+m}{s}+\binom{1}{r}\binom{n+m-1}{s}...\binom{m}{r}\binom{n}{s}+\binom{m+1}{r}\binom{n-1}{s}+...\binom{m+n}{r}\binom{0}{s}$, I see that it is basically adding together the various ways of drawing a constant $r$ and $s$ from two changing populations that sum up to $m+n$. However, I don't actually see where the $+1$ comes from. Is there anything wrong with my intepretation of the LHS? $$\sum_{i=1}^n (i-1)(n-i) = \binom{n}{3}$$ I know that RHS is counting the number of subsets of 3 that can be formed from $n$. However, I do not have any idea of how to be interpreting the LHS.

Restrictions on the variables for this identity are as follows: $a \geq m \geq 0$ and $n \geq b \geq 0$.  I have not gotten far with this, but these are my very rudimentary thoughts: We need to define a special element, somehow, and then carve up the $m + n$ remaining elements to be chosen out of the remaining pool of $a + b$ elements by writing $a + b = a - i + b + i$. From the $a - i$ pile, we choose $m$ things. From the $b + i$ pile, we choose $n$ things. My problem is, what is going on with this special element? How is it being defined so as to split things in this precise way?  A hint would be great for the moment.


When I copy the specific Excel cells and paste them on a Stack Exchange site, it's automatically pasting as an image. It would be great if it is pasted as the . OS   : Windows 10 Excel: Office 365 Version 1908 For example, after pressing Ctrl+V or ⌘+V, the following image is added:  Instead, the following native HTML table should be generated:     S/No Item Qty     1 Product 1 10   2 Product 2 15   3 Product 3 30

I am trying to ask a question on SE, have some mock data in Excel I've copied, and am simply trying to paste in to my question.  I've done this before dozens of times, but suddenly am having this issue.  However, when I do so, I get prompted to upload an image. (This happens with Ctrl + V and also right click --> Paste):    Am I overlooking something?  Edit: Playing around, I can copy from Firefox/browsers and Word, and paste in to the box as usual. Excel seems to be the only one giving the issue so far.  Edit2:  are still having this issue.


I'm trying to make this test method work.      //test @isTest  private class CoreValuesExtTestClass {     static testMethod void validateCoreValues() {        Core_Values__c cv = new Core_Values__c(Account__c='6', HSE__c='6', Professionalism_Integrity__c='6', Quality_Accuracy__c='6', Technology_Innovation__c='6', Value_for_Money__c='6', Timeliness__c='6');        System.debug(cv.Account__c + cv.HSE__c + cv.Professionalism_Integrity__c + cv.Quality_Accuracy__c + cv.Technology_Innovation__c + cv.Value_for_Money__c + cv.Timeliness__c);         // Insert book        insert cv;         // Retrieve the new book        cv = [SELECT Account__c, HSE__c,Professionalism_Integrity__c,Quality_Accuracy__c,Technology_Innovation__c,Value_for_Money__c,Timeliness__c FROM Core_Values__c WHERE Id =:cv.Id];        System.debug(cv.Account__c + cv.HSE__c + cv.Professionalism_Integrity__c + cv.Quality_Accuracy__c + cv.Technology_Innovation__c + cv.Value_for_Money__c + cv.Timeliness__c);         // Test that the trigger correctly updated the price        System.assertEquals('6', cv.Account__c);        System.assertEquals('6', cv.HSE__c);        System.assertEquals('6', cv.Professionalism_Integrity__c);        System.assertEquals('6', cv.Quality_Accuracy__c);        System.assertEquals('6', cv.Technology_Innovation__c);        System.assertEquals('6', cv.Value_for_Money__c);        System.assertEquals('6', cv.Timeliness__c);     } }   for this class  public class CoreValuesExt {     ApexPages.StandardController sc;     public boolean readonly {get; set;}     public Core_Values__c cv {get; set;}     public integer countEdit = 1;     public string buttonValue {get; set;}     public integer recordScan;      public CoreValuesExt(ApexPages.StandardController sc)     {         this.sc = sc;         cv = new Core_Values__c();         cv.Account__c = sc.getid();          readonly = true;         buttonValue = 'Edit';         recordScan = [SELECT COUNT() FROM Core_Values__c WHERE Account__c = :cv.Account__c];        if (recordScan != 0){        cv = [SELECT id, HSE__c, Professionalism_Integrity__c, Quality_Accuracy__c, Technology_Innovation__c, Timeliness__c, Value_for_money__c FROM Core_Values__c WHERE Account__c = :cv.Account__c];         }      }      public ApexPages.PageReference Save()     {         return sc.Save();     }      public void ApplyAction()     {         countEdit++;         Integer modolus = Math.mod(countEdit, 2);         String total = cv.HSE__c + cv.Professionalism_Integrity__c + cv.Quality_Accuracy__c + cv.Technology_Innovation__c + cv.Value_for_Money__c + cv.Timeliness__c;         if(modolus == 0)         {             readonly = false;             buttonValue = 'Save';         }         else         {             if(total != 'nullnullnullnullnullnull')                {             if (recordScan == 0){             insert cv;             readonly = true;             buttonValue = 'Edit';             }             else             {             update cv;             readonly = true;             buttonValue = 'Edit';             }             }         }        } }   Unfortunately, the tests pass nothing, how do I make this work. Any help would be appreciated, thanks

I need help. I am currently trying to test this code before uploading  public class CoreValuesExt { ApexPages.StandardController sc; public boolean readonly {get; set;} public Core_Values__c cv {get; set;} public integer countEdit = 1; public string buttonValue {get; set;} public integer recordScan;  public CoreValuesExt(ApexPages.StandardController sc) {     this.sc = sc;     cv = new Core_Values__c();     cv.Account__c = sc.getid();      readonly = true;     buttonValue = 'Edit';     recordScan = [SELECT COUNT() FROM Core_Values__c WHERE Account__c = :cv.Account__c];    if (recordScan != 0){    cv = [SELECT id, HSE__c, Professionalism_Integrity__c, Quality_Accuracy__c, Technology_Innovation__c, Timeliness__c, Value_for_money__c FROM Core_Values__c WHERE Account__c = :cv.Account__c];     }  }  public ApexPages.PageReference Save() {     return sc.Save(); }  public void ApplyAction() {     countEdit++;     Integer modolus = Math.mod(countEdit, 2);     String total = cv.HSE__c + cv.Professionalism_Integrity__c + cv.Quality_Accuracy__c + cv.Technology_Innovation__c + cv.Value_for_Money__c + cv.Timeliness__c;     if(modolus == 0)     {         readonly = false;         buttonValue = 'Save';     }     else     {         if(total != 'nullnullnullnullnullnull')            {         if (recordScan == 0){         insert cv;         readonly = true;         buttonValue = 'Edit';         }         else         {         update cv;         readonly = true;         buttonValue = 'Edit';         }         }     }    }   }  With this trigger.  trigger CoreValuesTrigger on Core_Values__c (before insert) {  Core_Values__c cvs = Trigger.new; CoreValuesExt.ApplyAction(cvs);  }   But when I try to save, I get a message saying:      Illegal assignment from List to   CoreValuesExt__Core_Values__c at line 3 column 1   "  How do I go through with this? I need help. Thanks


I'm looking for the software used to create the UI mockups in Ubuntu's documentation, for example, here:   Thanks.      Edit: The replies I got here are a bit off mark. I do agree, though, that my question is a duplicate. I eventually found the answer here:

As part of my job as a web developer, I spend an amount of time doing UI prototypes to show the client. It's a pain in the behind but sometimes it has to be done.  I've seen Shuttleworth (and the design team) pump out images like this:    That's made by something called ... Something that balances on top of Adobe Air (yack!) and costs $79.  I've tried it but it kept falling over. I think it had something to do with Air not the app itself. My point is if I'm paying out for something, I want it to be native.


d1 = {'Adam Smith':'A', 'Judy Paxton':'B+'} d2 = {'Mary Louis':'A', 'Patrick White':'C'} d3 = {}  for item in (d1, d2):     d3.update(item)  print(d3)   In this Python Code, the task is to merge the dictionaries and assign the merged dictionaries to the third dictionary. They used the for loop aproach which is a bit confusing for me as I'm not able to understand the loop part.   Could you help me determine that loop-debugging part?

I have two Python dictionaries, and I want to write a single expression that returns these two dictionaries, merged (i.e. taking the union).  The update() method would be what I need, if it returned its result instead of modifying a dictionary in-place. >>> x = {'a': 1, 'b': 2} >>> y = {'b': 10, 'c': 11} >>> z = x.update(y) >>> print(z) None >>> x {'a': 1, 'b': 10, 'c': 11}  How can I get that final merged dictionary in z, not x? (To be extra-clear, the last-one-wins conflict-handling of dict.update() is what I'm looking for as well.)


I'm programming in c#. I have written a method to generate random imei, which has 15 numbers from 0 to 9. I combine them using StringBuilder and return the whole code as string.  public static string randomIMEIgenerator() {     var builder = new StringBuilder();     while (builder.Length < 15)     {         builder.Append(Rnd.Next(10).ToString());     }     return builder.ToString(); }   Now the thing is that I want to run this method x times, because I want to generate x imei codes. Why when I write for loop I get this error?     An object reference is required for the non-static field, method, or   property   My main function:  private static readonly Random Rnd = new Random(); int x = 5; public static void Main(string[] args) {     for (int i = 0; i < x; i++)     {         randomIMEIgenerator();     } }   I also want to store all of those randomly generated imei's to an array. Should I just do it like that?  String[] array = new String[x]; for (int i = 0; i < x; i++) {     array = randomIMEIgenerator(); }   However my main question is about that error.  P.S. If I run this only one time, it generates one imei number. So the method randomIMEIgenerator is working properly.

Consider:  namespace WindowsApplication1 {     public partial class Form1 : Form     {         public Form1()         {             InitializeComponent();         }          private void button1_Click(object sender, EventArgs e)         {             //int[] val = { 0, 0};             int val;             if (textBox1.Text == "")             {                 MessageBox.Show("Input any no");             }             else             {                 val = Convert.ToInt32(textBox1.Text);                 Thread ot1 = new Thread(new ParameterizedThreadStart(SumData));                 ot1.Start(val);             }         }          private static void ReadData(object state)         {             System.Windows.Forms.Application.Run();         }          void setTextboxText(int result)         {             if (this.InvokeRequired)             {                 this.Invoke(new IntDelegate(SetTextboxTextSafe), new object[] { result });             }             else             {                 SetTextboxTextSafe(result);             }         }          void SetTextboxTextSafe(int result)         {             label1.Text = result.ToString();         }          private static void SumData(object state)         {             int result;             //int[] icount = (int[])state;             int icount = (int)state;              for (int i = icount; i > 0; i--)             {                 result += i;                 System.Threading.Thread.Sleep(1000);             }             setTextboxText(result);         }          delegate void IntDelegate(int result);          private void button2_Click(object sender, EventArgs e)         {             Application.Exit();         }     } }   Why is this error occurring?     An object reference is required for the nonstatic field, method, or property 'WindowsApplication1.Form1.setTextboxText(int)


Here are three ways to say the same thing. I wonder if there are particular rules regarding to the position of adverb phrases:     Then play those passages over and over again in your memory   Or,     Then play those passages in your memory over and over again   Or,     Then play over and over again those passages in your memory   I think the last is the worst choice but the first twos seem ok. The first is better because "over and over again" is closer to "play" so it is emphasized. Agreed?

For example:     Ever wish you could share information broadly   Could it be rewritten to:     Ever wish you could broadly share information   Are there any rules for the position of the adverbs.


I am remotely connected to a system using ssh and want to run nmap on a system from there. But every 5 minutes, my SSH connection breaks and so the process running on my shell stops.  How can I run nmap in the background so that any SSH session can interact with the process?

I sometimes have long running processes that I want to kick off before going home, so I create a SSH session to the server to start the process, but then I want to close my laptop and go home and later, after dinner, I want to check on the process that I started before leaving work. How can I do that with SSH? My understanding is that if you break your SSH connection you will also break your login session on the server, therefore killing the long running process.


In my Android ZTE, I'm trying to upload things. Let's say, I'm uploading a resume, I will get a message saying it can't be delivered due to low memory.  I have deleted things like games and pictures that I thought consumed my memory, but still, I get that message.  How do I increase my phone's free flash memory?

I have an Android Voyager, RCT6773W22B. It's version 5.0.  When I first got it, and years after that, I could download at least five apps downloaded at a time and have a great sum of pictures in my gallery. I would still have space after this. Over time, I would delete apps I didn't use anymore. If I wanted to download something else and there wasn't enough space, I would delete apps and/or pictures I don't need.  Now, I can't download anything due to internal storage. I have no apps, five pictures (not taken with the camera), and I've cleared the cache on everything except Chrome. It tells me my internal storage is completely full and I can't move anything to an SD card. What do I do?


I have a group called service in /etc/group that has user webserver as a member.   I am trying to write to a file in /home/service using user webserver. I have a script that confirms that user webserver has write permission to /home/service, yet when I want to write to /home/service/entries_for_processing, then I get a permission denied error, even though both /home/service, and /home/service/entries_for_processing are writable by group service.  What don't I understand about group permissions that it denies me permission to write to /home/service/entries_for_processing as a member of service group?  Below are the permissions of /home/service and /home/service/entries_for_processing:  # file: home/service/entries_for_processing # owner: service # group: service user::rw- group::rw- other::---  # file: home/service/ # owner: service # group: service user::rwx group::-w- other::---   By the way, the script I mentioned that confirms that user webserver can write to /home/service, also strangely confirms that webserver cannot write to /home/service/entries_for_processing nor to any other file I try to open or create in /home/service.

In my CMS, I noticed that directories need the executable bit (+x) set for the user to open them. Why is the execute permission required to read a directory, and how do directory permissions in Linux work?


So, I was browsing through Chrome for something around three days ago in Google, and when I clicked a search result, noticed a weird think happening in the URL bar. Generally, clicking a link shown in Google search results, let's say abc.com/somewebpagehere should lead me directly to that webpage. But, I saw that instead of taking me directly to that website, I was seeing this right after clicking the search results:    The URL was being prefixed by go.lnkam.com instead of google.com which we generally see. Searching on the web tells me that this is a malware issue, ran a full scan using Windows Defender but could locate none. Can someone suggest something better?  (P.S.: I've not checked whether this issue persists in other browsers or not, I rarely use them)

What should I do if my Windows computer seems to be infected with a virus or malware?  What are the symptoms of an infection? What should I do after noticing an infection? What can I do to get rid of it? how to prevent from infection by malware?   This question comes up frequently, and the suggested solutions are usually the same. This community wiki is an attempt to serve as the definitive, most comprehensive answer possible. Feel free to add your contributions via edits.


How would I be able to get N results for several groups in an oracle query.  For example, given the following table:  |--------+------------+------------| | emp_id | name       | occupation | |--------+------------+------------| |      1 | John Smith | Accountant | |      2 | Jane Doe   | Engineer   | |      3 | Jack Black | Funnyman   | |--------+------------+------------|   There are many more rows with more occupations.  I would like to get three employees (lets say) from each occupation.  Is there a way to do this without using a subquery?

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


I can't think of a word that would summarize this phrase into one coherent adjective. It's for a thesis I'm writing about a musical composer.

What is a one word substitute for something which is "easily understood"? I can think of clear but I guess there are other better words.  Edit 1.  Will the answer be different for easily understandable? (As opposed to  easily understood)  Edit 2. Here's an example to more narrowly indicate the sort of usage desired:     The manual should be precise and easily understandable.


I know there's something wrong with the way the indirect-object pronoun "him" and the gerund "having" are being used here, but I can't put my finger on it or find it on Google. Here's another example:  The whip was unable to muster the votes of her caucus members, due to them being divided over the amendments.

I assume that the following sentences are grammatically correct:   He resents your being more popular than he is. Most of the members paid their dues without my asking them. They objected to the youngest girl's being given the command position. What do you think about his buying such an expensive car? We were all sorry about Jane's losing her parents like that.   I'm still getting used to this possessive gerund structure. It sounded so weird to me at first. Is the structure used in both formal and informal contexts? Are there any alternative structures that result in the same meaning and are more frequently used? (Examples taken from )


Equation \eqref{eq:sp1} represents the reduced state of the system after tracing over environment.(Page number 358) $$\mathcal{E}(\rho) = \mathrm{tr}_{env}(\lbrack U(\rho \otimes \rho_{env} )U^{\dagger}\rbrack). \tag{8.6} \label{eq:sp1}$$ And then they say in page 359 that initially $\rho_{env} = |0\rangle\langle0|$ and then we apply $U$ to the combined state.(here $U$ is CNOT). The equation \eqref{eq:sp1} becomes (after plugging these values) $$ \mathcal{E}(\rho) = P_{0}\rho P_{0} + P_{1}\rho P_{1} \tag{8.7} \label{eq:sp2}$$ where $P_{m}=|m\rangle\langle m|$. How are they arriving at \eqref{eq:sp2}?

In the Quantum Operations section in Nielsen and Chuang, (page 358 in the 2002 edition), they have the following equation: $$\mathcal E(\rho) = \mathrm{Tr}_{env} [U(\rho \otimes \rho_{env})U^\dagger]$$ They show an example with $\rho_{env} = |0\rangle \langle0|$ and $U = \mathrm{CNOT}$, and claim that the final solution is: $$P_0\rho P_0 + P_1\rho P_1,$$ where $P_0=|0\rangle \langle0|$ and $P_1=|1\rangle \langle 1|$. These are my steps so far to get this, but I don't know how to trace out the environment after this: Let $\rho$ be $|\psi \rangle \langle \psi |$, so that $\rho \otimes \rho_{env} = |\psi, 0\rangle \langle \psi, 0|$. Applying the unitary $U$, we have $$ |00 \rangle \langle 00| \psi, 0 \rangle \langle \psi, 0 | 00 \rangle \langle 00 |  + |00 \rangle \langle 00| \psi 0 \rangle \langle \psi 0 | 10 \rangle \langle 11 | \\  + |11 \rangle \langle 10| \psi 0 \rangle \langle \psi 0 | 00 \rangle \langle 00 |  +  |11 \rangle \langle 10| \psi 0 \rangle \langle \psi 0 | 10 \rangle \langle 11 |. $$ I don't know how to trace out the environment in the above state. Also, I realize that I have considered only a pure state, if anyone can show it for a general state that would be great.


I am currently using biber with the style apa. \usepackage[backend=biber,style=apa,mincitenames=2]{biblatex}  I would generally like to cite only one author. However, for papers where I am co-author I would like to cite the first two authors. Is this possible? Example:  The work was previously proposed by author 1, et al., however it was also investigated in author2, myself, et al.  Is it possible to introduce a \citetwo command? Currently, I am using biber with mincitenames=2. However, I would prefer only citing two authors where it is useful.

I'm using the authoryear style in biblatex with the following options name length options:   maxcitenames=1, mincitenames=1, maxbibnames=999, minbibnames=999   So citations (usually issued with \cite) are properly typeset with only one author like     Shakespeare et al, The...   However I want to typeset a single citation (via \fullcite) with all authors listed, eg.     W. Shakespeare, J. Austen and D. Adams, The...   How can I temporarily increase the values of maxcitenames and mincitenames? Or is there another way to typeset only the \fullcite citatation with all names?


I think datum is the singular of data,but where I should use it???I am getting confused between both,if there is one data? Will I use datum? Please give me some proper example to clear out it.thank you.

Which sentence is correct:     In this section you can make a payment: verify carefully that all the data submitted is correct and confirm by clicking the Proceed button.   or     In this section you can make a payment: verify carefully that all the data submitted are correct and confirm by clicking the Proceed button.


I read this book back in middle school and I've been trying to remember more about it and possibly read it again.  I remember the cover was a greenish blue. It would have been around the 2004-2005 time frame. I remember the whole book had an overall dark and industrial dystopia feeling to it.  From what I remember, the book's main character was an orphan and imprisoned in a large orphanage where the kids where forced to work. There was some sort of accident during a routine transfer and he escaped with some other kids. These other kids ended up fighting a government-type military who was trying to capture them... there was also something to do with a creature or aliens.   I want to say it started with a "C".

I can't really remember how long ago it was, but I think the book was marketed towards children/teens.  All I remember is the basic premise of the story.  Some story about these unusual little blue electric critters that only certain people could see, and these kids took it upon themselves to go about destroying them since they fed off energy or something like that.  Not sure whether they fed off people or off electricity... or both maybe?  I think the dominant method of destroying them was an electric baton that was taken from law enforcement.  I wanna call them buzz batons, but that's probably thanks to Artemis Fowl.


I need to draw line from my central node to every other node. I know how to draw from point to point:           \draw[darkblue2, thick](virt-manager)--(libVIRT);   I know also that I can specify where the draw goes out/in with:  \draw[darkblue2, thick][out=270](virt-manager)to[in=110];   But the draw are rounded and that's not what I want. Here is the code, in black this is what I need:  \documentclass{article} \usepackage[margin=2.5cm]{geometry} \usepackage{tikz} \usetikzlibrary{arrows.meta,                 backgrounds, bending,                 calc, chains,                 %decorations.pathmorphing,                 fit,                 %petri,                 positioning,                 quotes,                 shapes.misc}  \definecolor{darkblue}{RGB}{31,22,70} \definecolor{darkblue2}{RGB}{21,126,251} \usepackage{graphicx} \usepackage{float} \begin{document}   \begin{figure}[H]   \centering      \begin{tikzpicture}[     mynode/.style={fill=#1,minimum height=1cm,minimum width=5cm,rounded corners,                    draw=white,very thick,font=\sffamily\color{white}},     mynode/.default=gray!20]         \node[mynode=darkblue!50] (libVIRT)at (b) {libVIRT};         \node[above  = of libVIRT,mynode=darkblue!20, minimum width = 2cm] (OpenStack) {OpenStack};         \node[left = of OpenStack,mynode=darkblue!20, minimum width = 2cm] (virsh) {virsh};         \node[left = of virsh,mynode=darkblue!20, minimum width = 2cm] (virt-manager) {virt-manager};         \node[right =of OpenStack,mynode=darkblue!20, minimum width = 2cm] (oVirt) {oVirt};         \node[right =of oVirt,mynode=darkblue!20, minimum width = 2cm] (else) {autres};          \node[below = of libVIRT,mynode=darkblue!80, minimum width = 2cm] (kvm) {kvm};         \node[left =of kvm,mynode=darkblue!80, minimum width = 2cm] (ESX) {ESX};         \node[left =of ESX,mynode=darkblue!80, minimum width = 2cm] (LXC) {LXC};         \node[right =of kvm,mynode=darkblue!80, minimum width = 2cm] (Xen) {Xen};         \node[right =of Xen,mynode=darkblue!80, minimum width = 2cm] (autres) {autres};          \draw[darkblue2, thick][out=270](virt-manager)to[in=110](libVIRT);      \end{tikzpicture}        \caption{blabla} \end{figure}       \end{document}

Sorry if duplicate (I'm sure duplicate) but I really can't find the way to do it in manual. I have created next block chain.     Here you can see curved line between last and third blocks. But I want something like this:  And the question: how can I сonnect them in this way? I'm sure that it is pretty simple. MWE:  \documentclass{article}  \usepackage{tikz} \usetikzlibrary{shapes,arrows,positioning,automata}  \begin{document} \begin{tikzpicture} \node[draw, thick, rectangle] (0) {Data arrival}; \node[draw, thick, rectangle, below of=0] (1) {Coks backoff procedure}; \node[draw, thick, rectangle, below of= 1] (2) {Get trigger-frame?}; \node[draw, thick, rectangle, below of= 2] (3) {Performs backoff procedure}; \node[draw, thick, shape aspect=2.7, diamond, below =0.5cm of 3] (4) {$b<0$?};   \path[>=latex, auto = right,every loop]  (0) edge[] node {} (1) (1) edge node {} (2) (2) edge node {} (3) (3) edge node {} (4) (4.east) edge[in=0, out=0, looseness=3] node[right] {N} (2.east) ;      \end{tikzpicture} \end{document}


I am trying to display something like    ó í ö ß   ... basicalliy European alphabet Italy, France, Spain, Portugal, Germany. Should not be too hard.  I load this package \usepackage[utf8]{inputenc}. As far as I know utf-8 contains these characters. But, when I compile, I get     Unicode char not set up for use with latex    And Fórum turns out to be nothing more then a F. Why is that?

TeXShop seems to default to 'Western (ISO Latin 9)', but a template I've been using is defaulting to 'Western (Mac OS Roman)'.  I'm using a package   Which encoding should I use with TeXShop on a Mac?    NB I'm using TeXShop for undergraduate mathematics assignments in english only.


I recently saw this video about an HR lady explaining how ML algorithms are used to screen CVs, once you apply for a role on company's website.   She says you should copy and paste the job description on your CV, in white, so that it is not visible, and the ML algorithm will pick up your CV for it to be reviewed by HR...  Is there any way I can do this on LaTeX?

I am trying to make a picture for the cover of my thesis using LaTeX. I have a background picture and I would like to have transparent (math) text on top of it, how do I achieve this? I have tried to install the transparent package, but was not successful.


I have a terrible problem, my joomla website is being abused to massively send spam. I have no clue on what is actually happening, but my postfix mail queue is constantly filled with thousands of spam mails being send from my server to external mail addresses. As a from-address a randomly created alias on my domainname is being used.  To solve this problem I would like my Postfix mail server to only process mail from known mail aliases... just I have no clue on how to achieve this and the technical information I can find about postfix just is to dificult for me to understand.  So I was hoping that somebody could tell me how I can configure my postfix mailserver to only process mail (that is from internal to external) for known mail aliases (or at least a list of mail address that can be used in the from-field and all other mail just being rejected).

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


I recently came up with the following concept. It is very simple, and may have been thought of before.  A picture says more than a thousand words, so here is it explained in a picture:   Note that water was used to make the example easier to understand. Another gas (denser than Gas A and B) could be used instead, resulting in less friction than when using water.    At first glance, it seems that this machine could run for an indefinite amount of time.  But I do not deem it possible to break the law of energy conservation. However, I have a hard time finding out what kind of force would cause this machine to slow down and stop.

I realize this isn't possible, but I can't see why not, especially if you change the model a little bit so that the balls simply travel through a tube of water on the way up, rather than exactly this model.  Please be clear and detailed.  I've heard explanations like "the balls wouldn't move" but that doesn't do it for me - I really do not see why the balls on the right would not be pulled/pushed up, and the rest of the chain wouldn't continue on.


I obtained a model fit: Sales = 1020 -8.8*Price +2.1*online reputation  after substituting the value of online reputation, I came out with following demand equation: 1036.8-8.8*Price Now to take out the revenue (sales*Price) I converted it to revenue function: 1036.8*Price - 8.8*Price^2  Now can I implement MAB for finding the price in order to maximize the revenue

I ran linear regression on my hotel reservation data and obtained the following model fit in R:  Sales = 170.2 + 3.6*Days_left_to_checkIn + 7.6*Revenue - 9.6*Room_Rate -7.67*cancellation_price + 4.8*Number_of_cancelled_Room -8.9*Online_reputation_of_Hotel  After this, I used the Optimize function to optimize the equation for maximum revenue (Revenue = Room_Rate* Sales)  after substituting all the values of variables I got this equation  f=-9.6*Room_Rate^2 + Room_Rate*253.56  Optimize(f, lwr=10, upr=524)  What is the next step to calculate Room_Rate to maximize the revenue (revenue = Room_Rate * Sales)? Is there any better way to optimize the function of demand?


Two questions I asked received some downvotes on Stack Overflow.   Has anyone encountered random script errors on comment lines in IE8?   Does object literal notation containing functions execute faster than plain functions?   Question one is not a poll, it asks if this is a known problem.  Question two is a question about code performance that has a technical answer not open to debate, I just don't know it.    Questions I would not ask on SO:    3) Is a verbose programming style an issue when compression, minification and obfuscation are available? 4) Can someone provide a list of available obfuscation tools?  Those involve opinion, discussion, and (as I just learned) lists. Would these questions also be voted down or rejected on Programmers.stackexchange.com or is that a more appropriate venue?  Related to this, is Programmers  the appropriate place for subjective and discussion oriented questions instead of using Stack Overflow?

There seems to be more than a few computer science/programming Stack Exchange networks (is that the correct term?). Stack Overflow, being the first, has by far the most users, questions, and answers.  What is the reasoning for creating the others, and are there clear guidelines for which kinds of questions should be posted? I can see a large amount of potential overflow, many cases of people not getting a good answer to their question, because the person who has the answer isn't browsing that particular network at the moment.  I understand that they were probably created for organizational purposes, but wouldn't it almost make more sense to just have them as categories under Stack Overflow, keep them separated but still connected, instead of making people have to create multiple 'account's, one for each network?  I am sure there was a very good reason to break them up, but as someone that is new to SE, it can be somewhat intimidating to decide which one to post in to ensure you get a good answer. For example, if I am a computer science student, my first instinct might to be to post in the computer science network, until I see that it literally has 1% of the users as the Stack Overflow network, which still seems to be for programming/computer science related questions.  So my second instinct would then to be to post it into the Stack Overflow site on the basis that I have a significantly higher chance of my question being seen and getting a good answer. Then I notice that there is also a 'programmers' network, and I don't even begin to know where that fits in. I, and I am assuming most people, will probably just post on Stack Overflow to be safe.  My question is, other than the short little description blurb of each one, is there a clear cut set of guidelines which what each network is intended for, what kinds of questions should go to each one, and is anything being done to encourage people to post in these newer, smaller (more specialized?) networks as opposed to just posting in big daddy Stack Overflow?  Now again, this is for computer science/programming/"why isn't this code doing what I want?" related questions, I am not saying that if I had a question about Linux or WordPress or something I would have the same confusion.


NOOB WARNING I was using my computer as normal when I got a notification that I was almost out of space in my computer. I checked in files and it said I had 420 gb or something left. I thought that was weird. I had recently plugged in a Harddrive in my computer to install Windows on because I had some troubles before while installing Windows before on my ssd. I unplugged the hdd and I tried booting my pc without the hdd plugged in (btw I had nothing installed on this drive) but when I booted it came in to this weird black screen with a lot of text on. I cant do anything, I have tried to press ctrl alt f1 or f2 but they dont work and neither does ctrl alt t. I dont know what to do because im a noob with ubuntu. I have plugged the drive back in again but I keep booting in to the same black screen with text on. I run version 18.04 (I think) right now,

I am trying to boot Ubuntu on my computer.  When I boot Ubuntu, it boots to a black screen.  How can I fix this? Table of Contents:


founded the site , which allows bypassing publisher paywalls.  If this service is used by researchers to access papers that would otherwise be out of their reach - due to their university not having subscribed to publishers or not being able to buy papers due to budget constraints - is it a good idea / wise to thank Alexandra in the Acknowledgement section of a paper citing the otherwise unattainable papers?  For example, "We would like to thank Alexandra Elbakyan for her work / contributions to science" without explicitly mentioning any specifics.  A similar question was already asked with the top rated answer pointing out that it would be unwise for paper authors to . This seems like a reasonable point.  Reseachers thanking someone for their contribution to science does not seem illegal and might get some readers of a paper to research the background of the acknowledgement.

My stance is that these websites are a great boon to the research community and they were certainly extremely helpful for my research. I think they should be applauded rather than persecuted, and while they may be illegal now, I think a way to make them legal should be found (in the same way I can download articles legally through my university's subscription to all the major publishers and journals).  Can I thank them in the acknowledgements section of my thesis?


I don't understand why after getting value from hashmap and updating hashmap, the local value changing at updated value. I always thought that java works on pass by value not by reference. @Component @RequiredArgsConstructor public class ParametersCompare {      @NonNull     private final ParameterRepository parameterRepository;      public boolean isAnyChange(String object, List<Parameter> currentParameter) {         Map<String, String> parameterHistory = parameterRepository.getHistoricalParameter(object);         parameterRepository.updateParameters(currentParameter, object);         return isAnyChange(parameterHistory, currentParameter);     }   @Service public class ParameterRepository  {      private final Map<String, Map<String, String>> oldParameters = new TreeMap<>();      public void updateParameters(List<Parameter> currentParameters, String object) {         Map<String, String> oldParameters = this.oldParameters.computeIfAbsent(object, s -> new HashMap<>());         updateParameters(currentParameters, oldParameters, object);     }      public Map<String, String> getHistoricalParameter(String object) {         Map<String, String> currentParameters = this.oldParameters.get(object);         if (object == null) {             return Collections.emptyMap();         } else {             return currentParameters;         }     }       private void updateParameters(List<Parameter> currentParameters, Map<String, String> oldParameters, String object) {         currentParameters.forEach(parameter -> oldParameters.put(parameter.getName(), parameter.getValue()));         this.oldParameters.put(object, oldParameters);     } }  After line parameterRepository.updateParameters(currentParameter, object);  oldParameters is changing to variable received from currentParameter. Thanks in advance for pointing why is changing. best regards

I always thought Java uses pass-by-reference. However, I've seen a couple of blog posts (for example, ) that claim that it isn't (the blog post says that Java uses pass-by-value). I don't think I understand the distinction they're making. What is the explanation?


I know that,  $S=\left(\displaystyle\frac{1}{1^3}+\frac{1}{5^3}+\frac{1}{9^3}\cdots\right) - \left(\displaystyle\frac{1}{3^3}+\frac{1}{7^3}+\frac{1}{11^3}\cdots\right)$  which is why it probably holds some kind of relation to the zeta-function. I tried looking it up on the internet but couldn't find anything related to $\zeta{(2k+1)}$  I want to show that $S=\displaystyle\frac{\pi^2}{32}$  Any hints ? (not asking for a complete solution) Thanks.

Prove that : $$\sum_{k=0}^{\infty} \frac{(-1)^{k}}{(2k+1)^3}=\frac{\pi^3}{32}.$$    I think this is known (see ), I appreciate any hint or link for the solution (or the full solution).


There is a combinatorics problem I want to tackle by writing a program for it. I want feedback on the algorithm I have thought of implementing. I have not implemented it yet because I want to first discuss all the possibilities (and it is obvious that a naive implementation would be useless).  According to , Code Review is supposed to be used to discuss the implementation of the algorithm. The problem is that I do not have any code to review, and I precisely want to avoid writing it until I've had the discussion.  I am assuming either Programmers or Computer Science, but it'd be good to know before asking.


<lightning-output-field variant="label-hidden" field-name="Company__c">                             </lightning-output-field>   it showing black i want to change the color of my output how i can achieve this

How can I change the colors of lightning-button?  I tried doing this in my css:  .my-button {     background-color: #14a6bc;     color: #ffffff; }   and applying that class to my <lightning-button> and removing the variant but I still get the base colors? I am trying to use these examples:


Attack on Titan has lots of Germanic features such as the music and wall names. In the case of the walls:     "Rose" was the East Germany's secret codename plan to build the Berlin Wall.   Where does the other wall names Sina and Maria come from? Are there any references to the walls' names inside the story-line?

I'm not sure whether this question will make sense or not but what is the symbolism or meaning behind the logos or symbols that are associated with the walls of Maria, Rose & Sina?      Are they suppose to represent the current King or are they some sort of recognizement of some past Kings and Queens in AOT in the last 100 years? What are the logos suppose to mean? Who is in them? If its not a person, is it suppose to represent or show how humans have managed to survive from titans in 100 years?  I haven't watched the anime in a while so whether it was revealed or not (I am not sure) however I am pretty sure they didn't address it. Does anyone know?


How do I convert a string to a byte[] in .NET (C#) without manually specifying a specific encoding?  I'm going to encrypt the string. I can encrypt it without converting, but I'd still like to know why encoding comes to play here.  Also, why should encoding even be taken into consideration? Can't I simply get what bytes the string has been stored in? Why is there a dependency on character encodings?


I'm making a blackjack game as a beginners project. I'm having trouble with exiting multiple loops. Instead of exiting the blackjack game and stopping the program that's running when the input is "Leave" the loop continues.  This is the part of my code that I'm having problems with.  def deal_cards():     while deck != []:        # code here that's irrelevant          while player_sum <= 21:             if player_sum == 21:                 print('BLACKJACK!')                 break             move = input('What would you like to do: ') # this is the player input. When the input is              if move == 'Hit' or move == 'hit' or move == 'HIT' or move == 'HIt' or move == 'hIt':                 card = random.choice(deck)                 deck.remove(card)                 player_sum = player_sum + card                 print('You got a ' + str(card) + '. Your sum is ' + str(player_sum))                 if player_sum > 21:                     print("YOU BUSTED")                     break             elif move == 'Stand' or 'stand' or 'STAND':                 print('The dealer has: ' + str(dealer_sum))                 while dealer_sum < 17:                     card = random.choice(deck)                     deck.remove(card)                     dealer_sum = dealer_sum + card                     print('The dealer has: ' + str(dealer_sum))                 if dealer_sum > player_sum and dealer_sum <= 21:                     print('You lost')                 elif dealer_sum == player_sum:                     print('Even. You get you money back')                 elif dealer_sum < player_sum:                     print('YOU WIN!')                 elif dealer_sum > 21:                     print('The dealer busted. YOU WIN!')                 break             if move == 'Leave' or 'leave' or 'LEAVE': # this is where the  # problem is. I want the entire program to end. I tried using break and # return but I don't seem to get it wotking.  welcome_screen()

Given the following code (that doesn't work):  while True:     #snip: print out current state     while True:         ok = get_input("Is this ok? (y/n)")         if ok.lower() == "y": break 2 #this doesn't work :(         if ok.lower() == "n": break     #do more processing with menus and stuff   Is there a way to make this work? Or do I have do one check to break out of the input loop, then another, more limited, check in the outside loop to break out all together if the user is satisfied?


I have a laptop with Ubuntu 12.04.6 LTS as the OS. I want to install  Ubuntu Studio 19.10 Eoan Ermine on this laptop which is the Asus Eee PC with USB 2.0.

This is the third time I've tried to install Ubuntu Server 14.04.03 64-bit on the same laptop, and each time it caused different problems.  Each time I wrote the same iso image to a USB flash drive by using a different application and OS.   Universal USB Installer (pendrivelinux.com) from Windows WinImage writer from Windows built-in image writer from Linux Mint 17.2    The iso image is the same in all three cases, the USB flash drive is the same, and the laptop is the same. However each time the installation of Ubuntu gave me different installation options. For example, the last time I installed Ubuntu, it didn't show all the packages to choose while installing (Basic Ubuntu server, etc.).


If I want someone to tell me the location of their Google Chrome User Data folder, is there a line they can paste in the omnibar to find out? In Firefox, I can type about:cache and it lists the location. But in Chrome it lists the content of the cache, not the location of the folder.

Where are the user profile directories of Google Chrome located in? It may seem like a very simple question, but I couldn't find it. I checked inside %APPDATA%, but there were noting relevant there. My OS is Windows 7 Ultimate x64 SP1.


I found in one book this way to declare variables:  class JerseyNumber {     public string Player { get; private set; }     public int YearRetired { get; private set; }      string JerseyNumber(string player, int numberRetired)     {         Player = player;         YearRetired = numberRetired;     } }   What will change if I'll remove the code:  { get; private set; }

In C#, what makes a field different from a property, and when should a field be used instead of a property?


I suggest providing a summary of the purpose of a StackExchange site up-front (i.e., near the top of the page).  Probably as a "Rounded/Squared Question Mark" button to the left of the site's logo, which upon click will pop up a box containing the site's description. Implemented this way, it won't become a clutter, and yet allow for a long-and-detailed description.  This feature will, IMO, help newcomers quickly find out what a certain SE Site is about.  (In fact, I'm not a newcomer (have been using SE for quite some time), yet when I landed on an SE Site I had to spelunk quite a bit to find out what exactly the site was about, to determine whether my question should be asked in that site or on another.)    Edit: After reading  I have to disagree. That question was specifically about new user. But this question is about a newcomer to an SE subsite, not necessarily a new SE user.  As I have explained in my endnote of the original question, *I* am not a new SE user, yet when I happened on a subsite that I have never visited before, say , I honestly have no idea what the site was about (i.e., what questions are welcome and what are not). And I have been a not-new-user for quite some time I forgot how to find info about the site.  I scroll dooooown, see "About Us", clicked... and off I went to a page about "The StackOverflow Company", not about the SE subsite. Only after clicking "Tour" did I find information to what a subsite is about. And that led me to a new page (or opens a new tab depending if I forgot to hold Ctrl or not).

Important: This question is being asked here, and not on the Programmers Meta,  because I believe that several SE sites suffer from this same, specific problem.    On Programmers, I see a pattern emerging.   New User sees the "Programmers" site title, and asks their incomplete, "fix my broken code" question. Community members comment that their question is off-topic, and recommend Stack Overflow.  New User says "thanks" and leaves, leaving their undeleted question for the community to clean up.    What seems clear to me is that:   New User has never seen the "What kinds of questions can I ask about here" page, or if they have, they've clicked through it without reading it. New User doesn't know how to move their question to the right place properly  (i.e. post on new site, delete from old site). Community cleanup of such questions is onerous.  The moderators on Programmers, following the principle that the community should moderate itself for the most part, are not proactive about removing such questions unless they're especially egregious. Migration is even more onerous.   OK, so we have the .  Here's what it says about topicality, about halfway down the page:    Note to those who are confused about Programmers' site scope: it's all right there, in black and white.  However, I do notice a problem.  It's circled in red.  That's our fault, the fault of the Programmers community.  What we really meant to say was "Don't ask your code troubleshooting questions here; those belong on Stack Overflow."  Coding tools deserves its own bullet.  We should fix that.  However, what are the chances that the user is actually seeing this, and evaluating whether or not they should ask their question based on this?  So here's my question, in two acts:  ACT I:  Is there a way to highlight the pain points of a particular site to new users specifically, so that we can be very clear that we don't want those questions that are clearly and unambiguously off-topic on our site, before they ask their question?  ACT II: Failing that, is there a way that we can fast-track the removal of such questions so that they no longer pollute our front page?


I am wondering if I had a  in play and played a , would it trigger a 'creature enters the battlefield' effect?

At what point do creatures entering the battlefield begin to be affected by enchantments and abilities of creatures already on the battlefield?  For example, 's ability triggers when creatures of power 2 or less enter the battlefield.  If I play a 2/2 creature while  is in play does the Mentor's ability trigger?  Similarly if I play a 2/2 human creature while  is in play (face up) does the Mentor's ability trigger? (It clearly has no effect if the card is transformed (face down) and the Mentor's ability would trigger.)


I am trying to install git on Ubuntu 14 with the following code  sudo apt-get install git   I get this output :  The following packages have unmet dependencies:  git : Depends: liberror-perl but it is not installable        Recommends: ssh-client E: Unable to correct problems, you have held broken packages   I am trying to install ssh-client by the following code:  sudo apt-get install openssh-client   then get this error:    Reading package lists... Done Building dependency tree        Reading state information... Done Package openssh-client is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  E: Package 'openssh-client' has no installation candidate

After upgrading from 10.04 to 12.04 I am trying to install different packages.  For instance ia32-libs and skype (4.0).  When trying to install these, I am getting the 'Unable to correct problems, you have held broken packages' error message.   Output of commands:  sudo apt-get install -f Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.   After running this:  sudo dpkg --configure -a foo@foo:~$ sudo apt-get install -f Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.


I want to play games from mini clip website, tried it in Firefox. Even though it has flash player installed through software center, the games are not working. I tried chromium, but was unable to install flash. Tried to follow the methods already explained in forums.  sudo apt-get update replies with a lot of errors like this:     W: Failed to fetch    Unable to connect to pk.archive.ubuntu.com:http:   Please help me to install Google Chrome with Flash Player.

I am trying to install chrome browser via command line.  I tried this:  $ apt-cache search chrome browser   The results show that the proper term is "chrome-browser," so I tried that:  $ sudo apt-get install chrome-browser   And then "Y" for the Y/n question.  But the installation threw errors.  Does someone see anything wrong with the commands I issued?


So I have followed the tutorial of the Unity Quiz game and wondered that If i want the game to present only up to 10 questions but the pool of questions have 20 or so so this is the script from the tutorial that I have somewhat edited.     I have a script called Game Controller   void Start()         {             dataController = FindObjectOfType<DataController>();                                // Store a reference to the DataController so we can request the data we need for this round          currentRoundData = dataController.GetCurrentRoundData();                            // Ask the DataController for the data for the current round. At the moment, we only have one round - but we could extend this         questionPool = currentRoundData.questions;                                          // Take a copy of the questions so we could shuffle the pool or drop questions from it without affecting the original RoundData object          timeRemaining = currentRoundData.timeLimitInSeconds;                                // Set the time limit for this round based on the RoundData object         UpdateTimeRemainingDisplay();         playerScore = 0;         questionIndex = 0;          ShowQuestion();         isRoundActive = true;     }   void ShowQuestion()     {         RemoveAnswerButtons();          QuestionData questionData = questionPool[questionIndex];                            // Get the QuestionData for the current question         questionText.text = questionData.questionText;                                      // Update questionText with the correct text          for (int i = 0; i < questionData.answers.Length; i ++)                              // For every AnswerData in the current QuestionData...         {             GameObject answerButtonGameObject = answerButtonObjectPool.GetObject();         // Spawn an AnswerButton from the object pool             answerButtonGameObjects.Add(answerButtonGameObject);             answerButtonGameObject.transform.SetParent(answerButtonParent);             answerButtonGameObject.transform.localScale = Vector3.one;              AnswerButton answerButton = answerButtonGameObject.GetComponent<AnswerButton>();             answerButton.SetUp(questionData.answers[i]);                                    // Pass the AnswerData to the AnswerButton so the AnswerButton knows what text to display and whether it is the correct answer         }     }      The script that Hold the Questions and Answers   using UnityEngine; using System.Collections; using UnityEngine.SceneManagement;  public class DataController : MonoBehaviour  {     public RoundData[] allRoundData;      void Start ()       {         DontDestroyOnLoad (gameObject);          SceneManager.LoadScene ("MenuScreen");     }      public RoundData GetCurrentRoundData()     {         return allRoundData [0];     } }

I need a quick algorithm to select 5 random elements from a generic list. For example, I'd like to get 5 random elements from a List<string>.


so I'm working on a basic Slot Machine program for my school and I keep getting this exception. I understand what it means but I dont understand why it reads my image files as null.   Exception in thread "main" java.lang.NullPointerException at ui.UI.<init>(UI.java:22) at ui.Driver.<init>(Driver.java:27) at ui.Driver.main(Driver.java:39)   Any help is NEEDED!  I'm also not sure how optimal my code is so any tips on that would be great.  package ui; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.util.ArrayList; import java.util.Collections;  import javax.swing.*;   public class UI extends JPanel { private ArrayList<ImageIcon> images; private ArrayList<JLabel> labels; JPanel panel1; JButton a;  public UI() {     ImageIcon imageGreen = new ImageIcon("C:/Users/Liam/workspace/CSE115-Lab8a/Images/Green.png");     ImageIcon imagePurple = new ImageIcon("C:/Users/Liam/workspace/CSE115-Lab8a/Images/Purple.png");     ImageIcon imageRed = new ImageIcon("C:/Users/Liam/workspace/CSE115-Lab8a/Images/Red.png");      images.add(imageGreen);     images.add(imagePurple);     images.add(imageRed);     setLayout(new GridLayout(3, 2));       for(ImageIcon s : images) {         JLabel label = new JLabel(s);         labels.add(label);         add(label);      }     a = new JButton("SPIN");     add(a);      ActionListener click = new ActionListener() {         @Override         public void actionPerformed(ActionEvent e){             JLabel label = new JLabel();             removeAll();             updateUI();             Collections.shuffle(labels);             add(label);             updateUI();             }         };         a.addActionListener(click); } }   Driver  package ui; import javax.swing.*; import java.awt.*; import java.awt.Dimension;     public class Driver extends JFrame {  private static final long serialVersionUID = -3413552064004843029L; private JPanel panelMain; private UI panel;  public Driver() {     setLayout(new GridLayout(2, 1));     setPreferredSize(new Dimension(420, 90));     setResizable(false);     setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);      panelMain = new JPanel();     panelMain.setBackground(Color.WHITE);     panelMain.setBounds(0, 0, 420, 90);     panelMain.setPreferredSize(new Dimension(200, 40));     add(panelMain);      panel = new UI();     panelMain.add(panel);     pack();       }  public static void main(String[] args) {     Driver frame = new Driver();     frame.setVisible(true);   }  }   THANKS!

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?


Not able to figure out the difference between hard and soft voting in context to ensemble based methods  In my view they are doing the same thing.   In hard voting, the voting_classifier counts the number of each class_instance and then assigns to a test_instance a class that was voted by majority of the classifiers. In soft computing, there is a probability term coming that takes the average of probabilities for each class and then uses it to classify the test_instance.  How are they different from one another? Any mathematical formulation etc. that could make the difference between them more obvious?  For soft voting classifier, I also read that "it gives more weight to highly confident votes". How is it implemented mathematically. Is it the weighted average that the author is talking about or anything else?

I'm reading . Then I'm not able to figure out the difference between hard voting and soft voting in context to ensemble based methods.  I quote descriptions of them from the book. The first two images from the top are description for hard voting, and last one is for soft voting.        In my view hard voting is majority decision, but I don't understand soft voting and the reason why soft voting is better than hard voting. Would anyone teach me these?


Canon 70D does provide 3 options of getting raw images - Small, Medium and Raw. I would like to know whats the difference between 3. Recently i did my tour and got some very good results from medium raw images. Would like to know the following things 1. I do understand size of the image varies in the 3 cases and what is the extent of information loss in Full vs Medium Raw 2. Which option to use in what condition. 3. Didn't look like 70D did any software processing in case of any of the raw images but does it w.r.t Medium and Small Raw

Most mid- and high-end DLSRs offer two or three sizes for RAW capture.  When the camera is generating the medium or small sized RAW files, how does it make them smaller?  Does it capture less information onto the sensor?  Does it capture the full amount of information and then apply some sort of in-camera compression?  Does it do something else that I'm not describing?


In my samsung galaxy s4, i am playing my youtube playlists like 10 or 20 musics and when i switch off the screen then the music stops.  How can i play forever the music even the screen is on or off?  For example:  1) i am in Gym  2) i open the youtube music playlist and let it play by switching off my screen and head phone is on  3) now when i am doing my workout the music is stoopped  How can i keep it play forever unless i manually close it.

The stock YouTube app (here on 2.1-eclair, but applies to all android versions) stops playing when I minimised, switched to another application or even when I lock the phone. And when I resume it restart downloading the clip from the beginning. Is there any way that I can play YouTube clips in the background? Note, I only the audio to continue playing.


A hash function H is secure in terms of pre-image resis-tance. Does this imply that H has second pre-image (aka weak collision) resistance?

Let the preimage resistance be defined as »given a hash value $h$, it is hard to find any message $m$ such that $\operatorname{hash}(m)=h$«, and let the second preimage resistance be defined as »given a message $m_1$, it is hard to find any message $m_2$ such that $\operatorname{hash}(m_1)=\operatorname{hash}(m_2)$«.  Then if you are given a preimage resistant hash function $H$, what modifications could we do in order to make a hash function $H'$ that is preimage resistant, but not second preimage resistant?  Someone suggested that we could do the following:     Take a preimage resistant hash function; add an input bit $b$ and replace   one input bit by the sum modulo 2 of this input bit and $b$.   But I am not sure if that will work, could anybody explain to me why that makes $H'$ not second preimage resistant?


When I scroll through the bash history with the arrow keys and hit (for example) the following string:  git clone hgit clone https://github.com/electron/electron-quick-start   In the next line of history I get something like this:  git clone hls   Where ls is the command from history and git clone h is my unwanted artifact.  The following lines from .bashrc are suspect:  PROMPT_DIRTRIM=2 YELLOW="\[\033[0;33m\]" RED="\[\033[0;31m\]" GREEN="\[\033[0;32m\]" ORANGE="\033[38;5;208m" PROMPT_COMMAND='echo -ne "\033]0; ${USER}@${HOST}\007"' PS1="${YELLOW}\u@\h:${ORANGE}\w ${GREEN}\$ "

I've tried to change my prompt by editing .bashrc:  export PS1="\e[0;32m[\u@\h \W]\$ \e[m"   This seems to work, but ctrl-r to access reverse history ends up with my typing not appearing in the same place as it will be interpreted (like ). It is fine when using the up or down arrows to select previous commands though.  I've had a look at that question, but can't seem to work out where to apply the escape characters in my prompt. I've tried a few combinations but then I break normal text typing functionality or simple back/forwards through history.  If you could include an explanation of which instances of characters need escaping and why, that would help me (and hopefully others) learn.


I have seen this code    void path(     const char * p);   » more...  void path(     const std::string & p);   » more...   Can I do the following modification, basically reversing the * and &.  void path(     const char & p);   » more...  void path(     const std::string * p);   » more...

I know references are syntactic sugar, so code is easier to read and write. But what is the difference between a pointer variable and a reference variable?


The sentence says that the opposite edges of the tetrahedron ABCD are perpendicular and the fact that  $AB^2+CD^2=AC^2+BD^2=BC^2+AD^2$ and I need to prove that the heights of the tetrahedron are concurrent, but I am stuck. I need a vectorial proof.

Can anyone give me a vectorial solution to the following problem:     Prove that if each pair of opposite edges of the tetrahedron $ABCD$ is perpendicular (that is, $AB \perp CD$ and $AC \perp BD$ and $AD \perp BC$), then the heights of the tetrahedron are concurrent.   Here, the heights (also known as the altitudes) of tetrahedron $ABCD$ are the perpendicular from $A$ to the plane $BCD$, and three other similarly defined perpendiculars.  Tetrahedra satisfying the condition of this problem are called , and this appears to be a known result.


I recently received a message telling me "Your bounty on question "" has expired - answer auto-selected."  But how can that be? None of the answers truly solved my problem, especially because I had to develop a workaround to finally have what I wanted.  And now 25 points have been given to an answer that didn't serve my purpose? Seriously?!  How do I undo this?

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


this is a simple add on just to select a loop so i can make the mean crease value 1  I do this alot and the constant moving mouse right is starting to hurt my had for models then will be subdivided.  I just want to press on a edge, (use the assigned shortcut key to active the add on) it will then select the loop and set the value of mean crease to 1.  This only works with the scripting editor, I can't get the add on to work after saving as test.py any help please.  I get the following errors :  addon_utils.disable: edge crease not disabled Modules Installed (edge crease) from 'C:\\Users\\RTJ\\Documents\\edge crease.py' into 'C:\\Users\\RTJ\\AppData\\Roaming\\Blender Foundation\\Blender\\2.80\\scripts\\addons' Traceback (most recent call last):   File "C:\Program Files\Blender Foundation\Blender\2.80\scripts\modules\addon_utils.py", line 351, in enable     mod = __import__(module_name)   File "C:\Users\RTJ\AppData\Roaming\Blender Foundation\Blender\2.80\scripts\addons\edge crease.py", line 35, in <module>     class EdgeCrease(bpy.types.Operator):   File "C:\Users\RTJ\AppData\Roaming\Blender Foundation\Blender\2.80\scripts\addons\edge crease.py", line 42, in EdgeCrease     bpy.ops.mesh.loop_multi_select(ring=False)   File "C:\Program Files\Blender Foundation\Blender\2.80\scripts\modules\bpy\ops.py", line 195, in __call__     BPyOpsSubModOp._view_layer_update(context)   File "C:\Program Files\Blender Foundation\Blender\2.80\scripts\modules\bpy\ops.py", line 157, in _view_layer_update     view_layer = context.view_layer AttributeError: '_RestrictContext' object has no attribute 'view_layer' "   the script:  bl_info = {     "name": "Edge Crease  ",     "author": "RTJ3DCosplay",     "version": (1, 0),     "blender": (2, 80, 0),     "location": "",     "description": "delete in context",     "warning": "experimental, not stable, at your own risk",     "wiki_url": "https://your web or web of the maintainer",     "category": "category where the addon is located" }  import bpy         import bmesh import mathutils import collections import math  from bpy_extras import view3d_utils from bpy.types import (         Operator,         Menu,         Panel,         PropertyGroup,         AddonPreferences,         ) from bpy.props import (         BoolProperty,         EnumProperty,         FloatProperty,         IntProperty,         PointerProperty,         StringProperty,         )  class EdgeCrease(bpy.types.Operator):     """Edge Crease"""     bl_idname = "object.edge_crease"     bl_label = "Edge Crease"     bl_options = {'REGISTER', 'UNDO'}   # this is all i'm trying to do,  # i select on edge then active this to loop select and set value to 1  # id be happy just to set to 1 each time      bpy.ops.mesh.loop_multi_select(ring=False)      bpy.ops.transform.edge_crease(value=1)    def register():     bpy.utils.register_class(EdgeCrease)    def unregister():     bpy.utils.unregister_class(EdgeCrease)   if __name__ == "__main__":     register()

I got this error message when I try to enable my addon.  dataBrush = bpy.context.blend_data.brushes  AttributeError:'_RestrictContext' object has no attribute 'blend_data'   Please some help    I am working on an dynamic palette for sculpt brushes


I know how robots.txt works but I am confused at one point, the point is what is the difference between these two, I know that they have the same function but which one is more valid than the other, and which one should I use when I want to make all my content public for search engines. (note: i know that disallow: /make other function) what is the difference between this: User-agent: * Allow: /  and this: User-agent: * Disallow:

User-agent: * Disallow: /  User-agent: Googlebot Allow: /   I use this command in my robots.txt file. But i do not think this is right. What should be the right command? Some article i have found where told not to do this in robots.txt  #Code to not allow any search engines! User-agent: * Disallow: /   And also found that we should disallow Googlebot except the js and css file.  User-agent: Googlebot Allow: /*.js* Allow: /*.css* Allow: /google/   So what should be the right way to do?


It'd be neat if users could enable Stack Exchange notifications through  and .

A very nice feature for Stack Overflow (and other Stack Exchange sites) would be to indicate the number of notifications (if any) in the browser tab like seen on Facebook:    Of course that would require automatic update if content has changed. Some kind of 'push-notification' which would be a nice feature as well.


I installed openssh server on Ubuntu 14.04.  My machine name is called "machine" and my username is "machine" so that when I'm on a terminal it says "machine@machine".  Question: When I try to connect to my machine from an SSH client (iPhone through 3G), what do I type in for:   username example.hostname.com:port   I assume the answer to (1) is "machine".  But what about (2)?  How do I find out my hostname and port?

Okay, so I have a PC in my home network, running Ubuntu on a VM with openssh server installed.    How can I remotely access it from another computer outside the home network, using the internet? What IP address do I use to connect to it? What kind of port-forwarding do I need to do?


In The Computer Journal I was looking at the  page, I did not understand the below instruction-     Authors should supply a list of between three and five referees who   would be suitable to referee the paper. Please enclose full name,   email and full postal addresses.   I thought after paper submission, the editors will review it & recommend if there any changes are necessary. But according to above instruction it seems that author has to provide suitable referee list. Then editors will review submitted paper.  In this specific context, What does referee mean? How does it differ from editor? Also if an independent researcher needs to submit paper, where does he find more than 2 referees? Is referee equivalent to peer?

Please submit, with the manuscript, the names, addresses (including   countries), and e-mail addresses of five potential referees who are   outside the authors' institutions and must not have conflict of   interest with the authors.   Do you think I should name 5 researchers from a similar area that are not affiliated with my university and co-authors? Is this what referees are?


The same windows appear as I switch on the computer. Like if I had selected "Save session for future logins" though I don't. I remember launching some GUI apps with sudo, can it be the source of the problem?  How can I fix it?

There's something strange going on with my Xubuntu setup (13.10 at the moment, but I remember having this issue in 13.04 as well, before upgrading). Each time I log in, the system reopens the applications that I didn't close before shutting down the computer last time. This is strange since in the session and startup settings I don't have the Automatically save session on logout setting checked. What can I do to fix this issue ?


Given $A$ be $n×n$ matrix such that $A^{n}=0$, but $A^{n-1}$ not equal to zero a vector $v$ belongs to $\Bbb{R}^{n}$. Proof that {$V,AV,\cdots,A^{(n-1)}V$}  is a basis.

Let $A \in Mat_{n \times n}(F)$ a matrix which satisfies $A^n=0$ and $A^{n-1} \ne 0$ for some positive integer $n$. Let $v \in F^n$ be such that $A^{n-1}v \ne 0$.  Prove that $\{v, Av, A^2v,...,A^{n-1}v\}$ is a basis for $F^n$.     So, from definition of $A$, I know that $A^iv \ne 0$ for all $0\le i \le n-1$. I know I need to prove the set is linearly independent and span $F^n$ to prove it's a basis, but I just don't know how.


It is possible to filter questions by user reputation ? I.e. if you mind to solve today more difficult questions and not ordinary (i know about featured questions but it is not same i mean).  Or you just want answer today on questions for users which reputation>100, because not feel good to filter newbie info.  Say it may be implemented as minimum asker's reputation in filter, may be minimum asker rating should be not more than half of your own.  Other case - you want learn a theme, and got guru info, so you can filter by tag and by minimum answerer reputation.  .

There seems to be a deluge of questions by folks with rep of 1-10. Many of these questions are "homework" or questions that are annoying to me "please read my 500 line script and tell me whats wrong with it" Is there any way to filter questions by reputation?


I used dd to copy an Ubuntu 18.04 installation from a 64GB partition on drive X to a 128GB partition on drive Y. See the below images for the problem; I am still limited to 64GB despite having a 128GB partition.         EDIT: Answer is below. I used resize2fs to grow the filesystem.

I resized the root partition with GParted, from 20 GB to 40 GB, but the filesystem still reports a size of 20 GB.  How can I use all 40 GB?    Update  The resized partition was an LVM Physical Volume (/dev/sda2), and the boot partition is ext4 (/dev/sda1).


My iMac went dead, and was trying to recover data from it by connecting Thunderbolt.  The dead iMac's hard drive did not appear on the other Mac. As a next step, I was trying to reboot to use Disk Utility for Target Disk mode, when my iMac showed this blinking icon with file and question mark.  What does this mean and what am I supposed to do?

Today i format my "OS X El capitan" partition for installing "Yosemite". But due an error in bootable yosemite usb it didn't install on this partition. After some hours when i turned on iMac and hold down "option" key for boot into usb but just blank screen and mouse show. And every time when i turend on iMac it only show flashing folder with question mark. I've tried to resolve it by reseting "NVRAM". But after restarting problem still same.  Also I've tried many "Startup key combinations for Mac" but didn't work any combination on startup.  Also i have important data in my other one partition. Please can anyone tell me what i do for resolving that issue Without loosing my data?


After updating Firefox to 40.0, the default profile fails to render any windows (including the menu bar and the rest of the GUI). However, I can navigate to any page, and copy page contents via the keyboard.  I've tried using firefox --safe-mode, but I get the same results: the window is blank as though nothing is rendering.  If I create and use a new profile via firefox --ProfileManager, the new profile works perfectly fine. I suspect something in default profile was corrupted.  How can I reset an existing profile, and retain my history, bookmarks, cookies, and ideally extension settings?

Mozilla firefox fills system memory and gets killed during startup if I use my "default" profile, even when started in safe mode. I'm using Kubuntu Linux.  $ firefox -safe-mode Killed $   Upgrading did not help (from firefox 3.6.13+build3+nobinonly-0ubuntu0.10.04.1 to firefox_3.6.16+build1+nobinonly-0ubuntu0.10.04.1_i386.deb).  I created a new profile and it works, safe mode is not required.  How can I repair the "default" profile? I'd like to have access to the data stored there (bookmarks, history, scrapbook, passwords etc).


I am not sure if this is a bug, but the 'recent questions'/'questions' feed button:           that is present on the bottom right side on most communities is not showing a parsed feed in Google Chrome.   I tried it on IE and it seems to work:    But in Chrome (v73) it shows the raw XML:

When I clicked on recent questions feed on bottom of the site, I was navigated to the /feeds endpoint; where I can see the code.   I don't know if this a bug, or does the page always show such code?


By the second law of thermodynamics, entropy tends to increase when the system is let on itself. And if entropy is a measure of disorder, how come mixing oil in water and letting the system reach equilibrium, ends up with the oil and water well separated? I see no disorder whatsoever, while in reality the entropy increased compared to the initial state (oil and water seemingly well mixed by e.g. shaking the container).

The oil, vinegar and other liquids in homemade salad dressing separate into layers after sitting for a while, making the mixture become more organized as time evolves.  Why doesn't this violate the 2nd law of thermodynamics?  I assume that the answer is that since the separation is due to gravity, the effect is due to an external force and so the system isn't closed which is necessary for the 2nd law, but I'm not sure.  If that's the answer, then what happens if I consider the whole system include the salad dressing, gravitational field and whatever mass is generating the gravitational field?  The entropy of the salad dressing seems to decrease and so the entropy of some other component of this system must be increasing, but it's hard to see what this other component would be.


I have a PDF with a strong password (contains uppercase, lowercase letter, digits, special characters). Now I don't know what's the length of the password. All I care about is contents of the file.  I am trying PDF Password Cracker Enterprise v3.1 it allows you to specify min and max password length and uses a Brute-Force type of attack. Problem is brute force attack takes a hell lot of time. For past 24 hours it's running the attack but so far it has only reached 6 characters.  Any way I can remove the password without actually cracking it !?

I have a couple of ebooks as PDFs with passwords, however my ebook reader (sony prs600) doesn't seem to support PDFs with passwords.  What is the easiest of removing the password from a PDF (I know the password, which presumably helps a lot).  It's a bit annoying buying a book and then only being able to read it in front of a computer.


I am trying to have a label with the text "I(X;Y)". However, it fails to compile due to the semicolon. Is there any way to escape the semicolon?  Edit: The following code works perfectly  \documentclass[tikz,border=3.14mm]{standalone}  \begin{document}  \begin{tikzpicture} \node at (0,0){$I(X;Y)$}; \end{tikzpicture} \end{document}   However, in my document I had \usepackage{breqn} and compilation does not complete when used with it.  \documentclass[tikz,border=3.14mm]{standalone} \usepackage{breqn}  \begin{document}  \begin{tikzpicture} \node at (0,0){$I(X;Y)$}; \end{tikzpicture} \end{document}

I just occurred a strange error in tikz. The following MWE never finishes on my machine (MikTeX, breqn Version 0.98e, tikz Version 3.0.1a):  \documentclass[11pt,a4paper]{article} \usepackage{tikz} \usepackage{breqn} \begin{document}     Some text     \begin{tikzpicture}         \draw (0,0) node {$|x|$};     \end{tikzpicture} \end{document}   Questions:    Why does this happen? (or is it just my configuration?) How can I avoid it? \| works fine, but that results in a double line and is not what I want.   Of course I could just remove breqn (then it compiles fine), but I'd like to avoid that since I use it often in my document.  This is the end of the produced log file:  \eq@hshift=\dimen204 \eq@given@sidespace=\dimen205 \mathindent=\dimen206 \eq@final@linecount=\count144 \eq@wdR=\dimen207 \EQ@continue=\toks29 \lr@level=\count145 \GRP@queue=\toks30 \c@parentequation=\count146 \GRP@box=\box56 \GRP@wholebox=\box57 \darraycolsep=\skip58 \cur@row=\count147 \cur@col=\co


I'm currently learning Computer Science (first year), and I have a task in my Java course, in which I need to create a Country class. One of the methods I need to implement is  public City[] getCities(), which, as the name implies, should return an array including all cities in the country. Here is the code I used to implemet that:  public City[] getCities() {     int cnt = INITIAL;     for (int i=INITIAL; this._cities[i] != null; i++) {         cnt++;     }      City[] existingCities = new City[cnt];      for (int i = INITIAL; i > cnt; i++)         existingCities[i] = this._cities[i];      return existingCities; }   Now on my main method:  Country us = new Country("USA"); System.out.println(us.getCities());   And the output looks like this:  [LCity;@7852e922   I couldn't find a solution where the return type is City[] (or arrayName[]), which is required.  Thanks in advance!

In Java, arrays don't override toString(), so if you try to print one directly, you get the className + '@' + the hex of the  of the array, as defined by Object.toString():  int[] intArray = new int[] {1, 2, 3, 4, 5}; System.out.println(intArray);     // prints something like '[I@3343c8b3'   But usually, we'd actually want something more like [1, 2, 3, 4, 5]. What's the simplest way of doing that? Here are some example inputs and outputs:  // Array of primitives: int[] intArray = new int[] {1, 2, 3, 4, 5}; //output: [1, 2, 3, 4, 5]  // Array of object references: String[] strArray = new String[] {"John", "Mary", "Bob"}; //output: [John, Mary, Bob]


in classical physics frequency represents how many cycles in one unit time, but I do not know how we define a frequency for a particle? what does it mean for a particle to have a frequency, the book I read it from just says Energy is proportional to the frequency of the photon but where is frequency?

If you emit a single photon, wait an interval, emit a second photon, wait the same interval, and keep repeating, is the resultant stream of photons describable by the frequency at which you emitted each one? Or does each photon have its own "frequency", independent of the rate of emission? I thought the former description explained the Doppler effect.


I'm working on the following problem:  Find all harmonic functions on $\mathbb R^2$ of the form $f(x^2+y^2)$, where $f$ is of class $C^2$.  What I've done so far: Define $u(x,y)=f(x^2+y^2)$. Then the second-order partial derivatives of $u$ are $$ u_{xx}=2f'(x^2+y^2)+4x^2f''(x^2+y^2),\\ u_{yy}=2f'(x^2+y^2)+4y^2f''(x^2+y^2). $$ If $u$ is harmonic then $u_{xx}+u_{yy}=0$, so we have $$ f'(x^2+y^2)+(x^2+y^2)f''(x^2+y^2)=0. $$ At this point I'm not quite sure what to do. Any help would be appreciated!

Find all real-valued functions $h$, defined and of class $C^2$ on the positive real line, such that the function $u(x,y)=h(x^2 + y^2)$ is harmonic.   I was thinking that it will be harmonic only if $h$ will be constant.  My attempt:    Since $u$ is harmonic, $$ u_{xx}+u_{yy}=0 $$  $ u_{xx}=4x^2h_{xx}+2h_x $ and $u_{yy}=4y^2h_{yy}+2h_y$. So,  $$ 4\Big(x^2h_{xx}+y^2 h_{yy}\Big)+2\Big( h_x+h_y \Big) =0$$ After that I stuck. Any hint will be appreciated.


I'm simply trying to make my character turn in his place, whether he's standing still or moving, currently, he isn't turning what-so-ever. Here is the code that I currently have for turning:  I AM NO LONGER USING THIS TURNING FUNTION vvv  void Turning() {     Ray camRay = Camera.main.ScreenPointToRay(Input.mousePosition);     RaycastHit floorHit;      if (Physics.Raycast (camRay, out floorHit, camRayLength, floorMask))     {         Vector3 playerToMouse = floorHit.point - transform.position;         playerToMouse.y = 0f;          Quaternion newRotation = Quaternion.LookRotation(playerToMouse);         playerRigidbody.MoveRotation(newRotation);     } }   So what should be happening is my character should turn and face toward wherever my mouse is pointing, but that isn't happening and I'm not sure why.  Thank you in advance for any assistance.    WHAT I AM USING NOW  I have alternatively tried another bit of code which I will post below, I completely got rid of what is above in place of this:   Vector3 mousePos = Camera.main.ScreenToWorldPoint(Input.mousePosition); transform.LookAt(mousePos);   This will actually make the camera follow the mouse, but it goes crazy, the camera seems to spin in circles rapidly : here is actually a gif of what is happening.  Could anyone help me figure how how to fix it?