my program consist of solving equations and asking the user if he want to solve more equation, so even though i enter yes to continue but the loop terminate ,this is my code       public static void main(String[] args) {      String goAgain;      double A, B, C, solution;     Scanner scanner = new Scanner(System.in);     System.out.println("This program will print a solution of an equation");     System.out.println("of the form A*X*X + B*X + C = 0, where A, B, and");     System.out.println("C are values that you enter.");      do {         System.out.println();         System.out.println("Enter values of A, B and C : ");         System.out.print(" A = ");         A = scanner.nextDouble();         System.out.print(" B = ");         B = scanner.nextDouble();         System.out.print(" C = ");         C = scanner.nextDouble();         System.out.println();         try {              solution = root(A, B, C);             System.out.println("your solution is : " + solution);           } catch (IllegalArgumentException e) {             System.out.println("Sorry, I can't find a solution.");             System.out.println(e.getMessage());          }         System.out.println("Do you want to solve another equation ? ");         goAgain = scanner.next();         System.out.println(goAgain);      } while (goAgain == "yes"); }
I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?
My understanding is that a question is historically locked because the information in it is too valuable for the question to be deleted.   But if the "valuable information" becomes obsolete, what happens then?  We cannot modify the question content, or the answers for a historically locked question, right? How to get distance when acceleration is not constant? Which variables should I transform, center, and/or standardize in my data for Principal Component Analysis? I have multiple datasets that I am attempting to use principal component analysis (PCA) on in order to infer the underlying structure of the data.  I'm attempting to predict growth increment of conifers (the response which apparently needed to be cube root transformed for my original linear models).  My predictor variables include: continuous (some log-transformed like size-related variables, some compositional, and some traditionally scaled); binary; ordinal; and nominal (of which I'm pretty sure I can order with respect to site productivity).  I'm mostly attempting to make inferences because some of my previous models from linear regression have not produced significant terms corresponding to categories like health or climate and I feel that they should have.  I've read in Joliffe (2002) that I might want to leave my compositional data uncentered.  Forgive my naiveté, but I'm wondering if I should also do this for my binary data.  It also seems that I might not want to scale these since they're already on a 0 - 1 scale but I'm not sure.  After only using my continuous predictors (including compositional variables), it appears that a size principal component makes up the largest portion of the variability and Joliffe also mentions that one might want to attempt a "double-centering" of the log-transformed data if this is the case.  I don't know if this is even possible since the log-transformed data only makes up a small portion of my datasets.  Finally, I should ask if having such a combination of data types will complicate analysis so much that it will make inferences unreliable.  I am currently using R for this analysis.  Thank you. Trying to Remember a Book that explored evolution of Dinosaurs to intelligence and then encountering humans Many, many years ago, I read a book where dinosaurs were assumed to have suvived the K-T event (or it never happened), and they evolved to intelligent species that used not only language (which combined sound, posture, and colour changes on their skin) but also used technology.  In the series, a human is captured or somehow gets integrated with one of the evolved dinosaur groups.  Again, from a very faint memory, the dinosaurs had a level of technology that would be about middle ages, and the humans were much more analogous to American Indian.  That's really all I can recall about the book, and I am trying to find it for my daughter to read.  Can anyone help me out? Getting a stack overflow exception when declaring a large array The following code is generating a stack overflow error for me  int main(int argc, char* argv[]) {     int sieve[2000000];     return 0; }   How do I get around this? I am using Turbo C++ but would like to keep my code in C  EDIT:  Thanks for the advice.  The code above was only for example, I actually declare the array in a function and not in sub main.  Also, I needed the array to be initialized to zeros, so when I googled malloc, I discovered that calloc was perfect for my purposes.  Malloc/calloc also has the advantage over allocating on the stack of allowing me to declare the size using a variable. How Conditional Random Fields and Logistic Regression could be the same? If you have read  tutorial about CRF, on page 4 under the section Classification, it wants to relate CRF to Logistic Regression (or Maximum Entropy, as it is known by this name in NLP community).   The formulation of Logistic Regression is said to be  $ p(y|x) = \frac{1}{Z(X)}exp \{ \lambda_y + \sum_{j=1}^{K}\lambda_{y,j}x_{j}\} $.  On the other hand, on the Wikipedia  for logistic regression, the formulation is  $ f(t) = \frac{1}{1+e^{-t}} $  and the classifier's formulation is the explanation of this formulation which is derived from Logistic Function.  My question is, first, how Logistic Regression and Maximum Entropy Classifier are related to each other and are identical?   Second, the CRF tutorial says Logistic Regression (or Maximum Entropy Classifier) is simple CRF model, how? jQuery autocomplete tagging plug-in like StackOverflow's input tags? I installed Ubuntu alongside Windows but I did not disable secure boot as someone told me it could cause problems with boot loader. So when installation finished and I rebooted, the system went straight into Windows. I went to Ubuntu IRC Support and they told me to turn off the secure boot and reinstall Ubuntu. I did that but my system still boot into windows.  This is a picture of partitions on my system:    This is my first Ubuntu install on my new laptop. I followed everdaylinux guide to install it and I used something else option. Watermark TextBox in WinForms migrating / merging iphone contacts I have an iPhone 6 (with proper iTunes backup) where all of my contacts where, but I bought a new iPhone 7 and had to initialize it as new iPhone, due to several time-related constraints, so now I have a few but new contacts on my new phone, but none of the older ones, but would be the best practice oriented, for just recovering the old contacts from the iTunes backups?  PS: I still have the old iPhone 6, so it could be used as "temporary storage" if needed. Which is correct if I want to request for a pen?        Can I have your pen please?   May I have your pen please? What is the difference between the dashed and solid attack bars? I was flipping through my Pokemon list to see which kind of attacks they had, and I notice there was a small different between the attacks. Some attacks contained a dashed blue bar where as others contained a solid blue bar.   What is the difference and significance between the two? How do I disable System Integrity Protection (SIP) AKA "rootless" on macOs [OS X] I am a super newbie for Ubuntu and basically need Ubuntu for a Python package.  I would like to run a Python file in say e:/username/folder1/folder2/python.py. I tried every method online and the only reply is bash: cd./e: No such file or directory. I am not sure whether it is because of the bash windows or virtualenv.  When I use bash on Ubuntu on Windows, ls, it says VIRTUALENV_DIR. cd, it says /home/username. The cd .. etc changes the directory a little, but not another drive, nor the folder I would like it to find. This can probably be fixed quite easily. I tried to research and find the answer to this but couldn't find anything relevant.     Basically, I can access my website perfectly through its url. (ex. example.com)  Whenever I click a link, go to my /wp-admin, or go to any other page, my domain changes into the IP address. (ex. instead of showing example.com/about it would show 192.111.223.4/about)  How do I fix this? Do I have to edit a file or can this be fixed by adding a domain record?  Thanks. Ubuntu 20.04 Font and UI elements too big on login I'm running Ubuntu 20.04 on an ASUS X99-E-10G WS w/ an NVIDIA 1080Ti and an LG 4k 32&quot; monitor which persistently gets recognized as 27&quot;. When I log in, the text of certain UI elements is ~2x the normal size. After I go to settings/universal access and turn large text on and then off again, everything is the normal size I expect. Screenshot after logging in  After turning &quot;large text&quot; on  After turning &quot;large text&quot; off  How do I get the conditions I have after cycling the &quot;large text&quot; feature to be present immediately after booting? I have the 440 version of NVIDIA's drivers installed. How to merge records for query set We have a question related to a DB query :   CREATE TABLE `Action` (   `id` int(10) unsigned NOT NULL AUTO_INCREMENT,   `emp_Id` int(10) unsigned NOT NULL,   `name` varchar(60) NOT NULL,   `updated_action_at` datetime(3) DEFAULT NULL,   `created_At` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,   `notes` varchar(400) DEFAULT NULL,   PRIMARY KEY (`id`),    KEY `action_empId_fk` (`emp_Id`),    CONSTRAINT `action_empId_fk` FOREIGN KEY (`emp_Id`) REFERENCES `Employee` (`id`) ON DELETE CASCADE,  ) ENGINE=InnoDB AUTO_INCREMENT=502004 DEFAULT CHARSET=latin1   CREATE TABLE `ActionAssignedTo` (   `action_Id` int(10) unsigned DEFAULT NULL,   `emp_Id` int(10) unsigned DEFAULT NULL,   KEY `actionassignedto_emp_id_foreign` (`emp_Id`),   KEY `actionassignedto_action_id_foreign` (`action_Id`),   CONSTRAINT `ActionAssignedTo_ibfk_1` FOREIGN KEY (`emp_Id`) REFERENCES `Employee` (`id`) ON DELETE CASCADE,   CONSTRAINT `ActionAssignedTo_ibfk_2` FOREIGN KEY (`action_Id`) REFERENCES `Action` (`id`) ON DELETE CASCADE ) ENGINE=InnoDB DEFAULT CHARSET=latin1  CREATE TABLE `Employee` (   `id` int(10) unsigned NOT NULL AUTO_INCREMENT,   `vendor_Id` int(10) unsigned DEFAULT NULL,   `name` varchar(40) NOT NULL,   `mobile_Number` varchar(15) NOT NULL,   `active` tinyint(1) DEFAULT '1',   `updated_At` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,   `created_At` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,   PRIMARY KEY (`id`),   KEY `employee_vendor_id_foreign` (`vendor_Id`),   CONSTRAINT `employee_vendor_id_foreign` FOREIGN KEY (`vendor_Id`) REFERENCES `Vendor` (`vendor_Id`) ) ENGINE=InnoDB AUTO_INCREMENT=511 DEFAULT CHARSET=latin1   We want to find the action created by employee with Action.empId = 4 along with the list of Assignee (an action can be assigned to multiple people)  We have the following query :   Select     notes,             Action.id,             AssigneeName.name,             ActionAssignedTo.emp_Id  from       Employee inner join Action  on         (Action.emp_Id = Employee.id  and        Action.emp_Id in (select Employee.id                               from Employee                               where Employee.vendor_Id = 1)) inner      join ActionAssignedTo  on         Action.id =  ActionAssignedTo.action_Id inner join Employee as AssigneeName  on         ActionAssignedTo.emp_Id =  AssigneeName.id where      Action.emp_Id = 4   Now, lets say if Action with id = 10 was assigned to 2 people : John (empId : 2) And Jack (empId : 5) --> the above query returns following results :  (columns from the query)  notes                       | Action.id | AssigneeName.name | ActionAssignedTo.emp_Id 1. Finish Designing Queries | 10        | John              | 2 2. Finish Designing Queries | 10        | Jack              | 5   If we observe the above results the first 2 columns get repeated for the Assignees for SAME ACTION ID  --> is there a way we can merge them something like   1. Finish Designing Queries |10         | { John : 2  , Jack  : 5}   Basically records being merged into one. Q&A blank in Stack Exchange Android app v1.0.95 - S10e/Android 10 Recently upgraded to a Samsung S10e and Android 10, but all Q&amp;A in the Stack Exchange app v1.0.95 are blank.  The title and comments are visible, but question/answer posts are just white space. Accessing the About page in the app is also blank.  I tried clearing data, cache and re-installing the app, but I still get the same behaviour. Why is Ubuntu using so much memory? I have just turned on my PC and have two applications running; Thunderbird and Firefox. Whatever else is running is part of Ubuntu's feature set (as well as a few indicators).  This has been ongoing for weeks, so I'm not sure if it's normal behaviour or not.  Right now, my memory usage indicator says that Ubuntu is using 41% of my 6GB of RAM. I haven't even opened Gimp or my other day-to-day things. I'll be buying another 6GB of RAM, this week, so that I don't run out when using Gimp or Openshot, for example.  An overview of my running applications shows that Nautilus is using the most, yet it isn't even open. This seems a little excessive, or am I missing something? Example of a ring with an infinite inclusion chain of ideals I'm trying to track down an example of a ring in which there exists an infinite chain of ideals under inclusion. (i.e. $I_1 \subsetneq I_2 \subsetneq I_3 \subsetneq...$)