Does two different regulators act as different power supplies for MCU and Relays
ATMEGA328P standalone sketch doesn't work as expected
Struct padding in C++ $F(x)$ versus $F[x]$ where $F$ is a field According to ,  The collection of all algebraic objects of a given type will usually be a proper class. Examples include the class of all groups, the class of all vector spaces, and many others. In category theory, a category whose collection of objects forms a proper class (or whose collection of morphisms forms a proper class) is called a large category.  I am aware of Russell's Paradox, which explains why not everything is a set, but how can we show the collection of all groups is a proper class? Fold a plane. then fold again Imagine a piece of paper and you fold it in half and then fold it again. that's what I am trying to do and cant. If I use bones the influence of the bones won't allow me to because I need 2 bones to control the same area. If I try shape keys it just deforms the mesh if I try to make it in multiple steps or does the wrong animation because it draws the shortest path instead of rotating from a point like a piece of paper would. Casting vs using the 'as' keyword in the CLR When programming interfaces, I've found I'm doing a lot of casting or object type conversion.  Is there a difference between these two methods of conversion?  If so, is there a cost difference or how does this affect my program?  public interface IMyInterface {     void AMethod(); }  public class MyClass : IMyInterface {     public void AMethod()     {        //Do work     }      // Other helper methods.... }  public class Implementation {     IMyInterface _MyObj;     MyClass _myCls1;     MyClass _myCls2;      public Implementation()     {         _MyObj = new MyClass();          // What is the difference here:         _myCls1 = (MyClass)_MyObj;         _myCls2 = (_MyObj as MyClass);     } }   Also, what is "in general" the preferred method? Does C1 code coverage analysis exist for Ruby? I'm currently using  to get C0 code coverage analysis for a rails project that I'm working on.  However, those results are practically meaningless- I have 100% coverage according to rcov (as it only covers C0 analysis) and I've barely written half the test cases for the functionality that exists thus far.  I'm used to the useful results from the code coverage in Visual Studio 2008 Team, which has C1 coverage.  Are there any tools that provide similar coverage for ruby? Working with large numbers in PHP To use  as you would require when using the  with large numbers (100,000+), it calls for some very large calculations.  When I multiply two large numbers (eg: 62574 and 62574) PHP seems to cast the result to a float. Getting the modulus value of that returns strange values.  $x = 62574 * 62574; var_dump($x);          // float(3915505476) ... correct var_dump($x % 104659); // int(-72945)  ... wtf.   Is there any way to make PHP perform these calculations properly? Alternatively, is there another method for finding modulus values that would work for large numbers? Brute-force attacking One Time Pads feasible? I have a ciphertext encoded with One Time Pad. I do not know the key. How can I find the possible keys which when decoded, will result in a meaningful plain text? I just came across this idiom in some open-source Python, and I choked on my drink.  Rather than:  if isUp:     return "Up" else:     return "Down"   or even:  return "Up" if isUp else "Down"   the code read:  return isUp and "Up" or "Down"   I can see this is the same result, but is this a typical idiom in Python? If so, is it some performance hack that runs fast? Or is it just a once-off that needs a code review? In going through the review tool I often come across poor quality answers to poor quality questions. In particular, I will occasionally see questions that are simply asking for links to products, asking for tools, etc. Here are three examples that I've come across just this morning.        Clearly it's appropriate to go to the question and vote to close it (these are examples of not constructive) if they aren't already closed, but what should be done with the answers?    Should the answer be marked for deletion? Much of the normal reasoning for not providing link only answers is defeated if the question is simply asking for links. I'm tempted to mark them as 'looks good' for that reason, because it's the question that is flawed. Is that correct, or should I evaluate all answers as if they were responding to a quality question? Apparently,     the Fisher analysis aims at simultaneously maximising the   between-class separation, while minimising the within-class   dispersion. A useful measure of the discrimination power of a variable   is hence given by the diagonal quantity: $B_{ii}/W_{ii}$.     I understand that the size (p x p) of the Between (B) and Within-Class (W) matrices are given by the number of input variables, p. Given this, how can $B_{ii}/W_{ii}$ be a "useful measure of the discrimination power" of a single variable? At least two variables are required to construct the matrices B and W, so the respective traces would represent more than one variable.  Update: Am I right in thinking that $B_{ii}/W_{ii}$ is not a trace over a trace, where the sum is implied, but the matrix element $B_{ii}$ divided by $W_{ii}$? Currently that is the only way I can reconcile the expression with the concept. Where to start with the Star Wars books? Basically asking what were the motives behind each theory. What was it that led physicists toward these ideas? Flag Question Link After 3k Rep I noticed from a question about flagging vs closing (forgive me, I cannot find the link, please post it if you know it), that flags are CONVERTED into close votes for questions automatically. Can somebody confirm this?  If confirmed, I was wondering why the link (again, for questions only) is simply not removed to avoid confusion? In the following method definitions, what does the * and ** do for param2?  def foo(param1, *param2): def bar(param1, **param2): I'm looking into developing an ordering app for a potential client. The main part that I'm concerned about in this question is the payment mechanism. I would assume that there are already multiple plugins or similar programs out there, but I'm not sure where (or if) I should be asking for recommendations. Credit cards: How is a cash advance different from a purchase? Why are the fees so high? Multi-partition multi OS bootable USB I want to create a recovery flash drive. I have my 8 gb flash drive[Kingston data traveller] with me. I also have the required .iso files for a>Ubuntu 13.10 b>Boot-repair disk c>AVG Rescue CD  I Wish to create 4 partitions(3 for each bootable .iso and one for data storage. Also, I want a way in which I can select which OS to boot each time I boot from USB.   So, is there a way to install GRUB on USB as well as the three other live distros? And how to create such a setup? How to make math font huge I have a situation very similar to the ones depicted in two previous questions I found ( and ), but still different (I address why my situation is different later on in the question).  The problem  I am really panicking, my computer has been in unbootable status for two days now and because of coronavirus lockdown, in Italy there is no any opened tech shop, at this point I do not know what to do and any help is very much appreciated.  I had a ~50 GB linux partition on the SSD (total ~250 GB) of my 15” Macbook Pro mid-2015. I created this partition to boot ubuntu back in 2016 and I used it regularly alongside macOS. About one year ago I updated to Mojave 10.14, and this is the macOS version my computer is running now (I am mentioning it because I suppose that the update changed the file system of my macOS partition to APFS, keeping unmodified the ubuntu partition, I guess).  Today I decided to remove the ubuntu partition, I started the computer on macOS, opened Disk Utility, find the ~50 GB partition assigned to ubuntu on the pie chart, I clicked on the “-“ sign to remove the partition and then “Apply”. Disk Utility returned to me instantly with an error (not remember exactly the text, but I remember that no error code was given) saying it could not perform the operation, so I googled a bit some solutions (MY COMPUTER WAS PERFECTLY WORKING) and I found a post suggesting to perform some operations from ubuntu, so I decided to restart my computer in order to open ubuntu - I repeat, it was perfectly working, many apps opened and fully working, etc. - and...  It booted into “GNU GRUB version 2.02”  I tried to restart my mac keeping “option” pressed, but it could only find the “EFI Boot” disk (picture attached) which is the one I usually select to boot Ubuntu. Also, Ubuntu now doesn’t even work anymore, because if I select “EFI Boot” it starts “GNU GRUB version 2.02”.  Now I really started panicking, I don’t care about data of the ~50 GB ubuntu partition, but so foolishly I haven’t backed up the ~200 GB macOS data, and I am just so affectionate to them, I would really like to recover them.  Data Recap   15” Macbook Pro mid-2015 Right now I am booting from the network. 256 GB SSD partitioned in: ~200 GB APFS macOS partition - FileVault encrypted - running Mojave 10.14 ~50 GB ubuntu partition - don’t remember the file system (data here doesm’t matter to me)   Photos Attached   diskutil list gpt -r show /dev/disk1 disk1 information from Disk Utility Disk Utility overview of the physical disk booting situation with only the “EFI Boot” partition   Why my situation is different  My situation is different from other questions because of 3 reasons:   The ~50 GB ubuntu partition is disappeared, maybe corrupted, indeed if you add up all the disk's size in diskutil list, you still miss ~50 GB. I have 2 disks at the same time (index 2 and index 3) that are in the FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF status When I call gpt -r show /dev/disk1 I don't get any "Suspicious MBR at sector 0" message unlike others users that wrote other questions.   Update 1  I just wanted to confirm that I am booting the mac from Network Recovery and also my Disk Utility version. Disk Utility Version is: "Version 13 (606)" - "Copyright 2002-2014 Apple Inc.". Is seems, indeed, pretty old.