How do I report that a question should be moved to a different site (from stackoverflow.com to superuser.com, in example)?
I posted a question which was closed as off-topic and it seems like it could fit on another site in the network. How can I go about moving it there?   What is migration? When can a question be migrated, and who can migrate it? When should I consider migration, and when is it inappropriate? What causes a migration to be blocked and what happens after? What causes a migration to be rejected and what happens after? Anything else I should know about migration?
Overflow: Visible on SVG What would you consider to be the best exception type to throw when an extension method is called on a null instance (where the extension method does not allow it)? Since extension methods are nothing but static methods you could argue that it should be ArgumentNullException, but on the other hand they're used like instance methods so it might be more natural to use the NullReferenceException. Let's take the following example:  public static string ToInvariantString(this IFormattable value, string format) {     return value.ToString(format, CultureInfo.InvariantCulture); }   This way a NullReferenceException will be thrown if the value parameter is null.   The other example would be:  public static string ToInvariantString(this IFormattable value, string format) {     if (value == null) throw new ArgumentNullException("value");     return value.ToString(format, CultureInfo.InvariantCulture); }   EDIT: In some of the answers you have pointed out that an extension methods can be called like a static method and in those cases a null reference exception would be wrong, which is a great point, and actually one of my concerns, not sure why I forgot to mention that in the question in the first place.   Someone also pointed out that it's wrong to throw a NullReferenceException, and yes, it is. That's why I don't throw it, I just let it happen (let the CLR throw it) by not guarding the method.  I think I favor the ArgumentNullException (that's what I've use so far) but I still think there is at least room to argue for an against the NullReferenceException since it seems more natural in most places where the method is going to be used. A positive harmonic function on the punctured plane is constant How to schedule a cron job to run a video fill every 5 minute? How to pass multiple operator properties via UI layout? Count and limit the number of files uploaded (HTML file input) For an odd prime $p$, prove that any primitive root $r$ of $p^n$ is also a primitive root of  $p$   So I have assumed $r$ have order $k$ modulo $p$ , So $k|p-1$.Then if I am able to show that $p-1|k$ then I am done .But I haven't been able to show that.Can anybody help me this method?Any other type of prove is also welcomed. Action to crop a photo with user input. The batch processing I'm stumped.  All I need to do is open my photo, have the action stop to wait for me to decide where the crop should be (to center the important part of the photo), then close that photo so the batch processing can go get the next photo.  I see the "inset stop" is the key, but it never allows me to crop, it just moves on to the next photo. How do you prove a number is prime? I am a software engineer but try to keep up with maths as I really enjoyed the subject at school. I just saw a great TED talk:   The talk states that the current largest known prime is $2^{57885161}-1$  This got me thinking - how does one actually prove whether a number this large is prime or not?  Is it just done by brute force via a computer algorithm or are there any well known mathematical techniques for doing so?  I would be really grateful for any pointers as I am eager to learn about these techniques (if they exist). pyPdf for IndirectObject extraction Following this example, I can list all elements into a pdf file  import pyPdf pdf = pyPdf.PdfFileReader(open("pdffile.pdf")) list(pdf.pages) # Process all the objects. print pdf.resolvedObjects   now, I need to extract a non-standard object from the pdf file.   My object is the one named MYOBJECT and it is a string.  The piece printed by the python script that concernes me is:  {'/MYOBJECT': IndirectObject(584, 0)}   The pdf file is this:  558 0 obj &lt;&lt;/Contents 583 0 R/CropBox[0 0 595.22 842]/MediaBox[0 0 595.22 842]/Parent 29 0 R/Resources   &lt;&lt;/ColorSpace &lt;&lt;/CS0 563 0 R&gt;&gt;     /ExtGState &lt;&lt;/GS0 568 0 R&gt;&gt;     /Font&lt;&lt;/TT0 559 0 R/TT1 560 0 R/TT2 561 0 R/TT3 562 0 R&gt;&gt;     /ProcSet[/PDF/Text/ImageC]     /Properties&lt;&lt;/MC0&lt;&lt;/MYOBJECT 584 0 R&gt;&gt;/MC1&lt;&lt;/SubKey 582 0 R&gt;&gt; &gt;&gt;     /XObject&lt;&lt;/Im0 578 0 R&gt;&gt;&gt;&gt;   /Rotate 0/StructParents 0/Type/Page&gt;&gt; endobj ... ... ... 584 0 obj &lt;&lt;/Length 8&gt;&gt;stream  1_22_4_1     ---&gt;&gt;&gt;&gt;  this is the string I need to extract from the object  endstream endobj   How can I follow the 584 value in order to refer to my string (under pyPdf of course)?? With a firmware password set on a Retina MacBook Pro, what are recovery options? I am considering setting a firmware password on my Retina MacBook Pro for security reasons. If I do this and later lose the password (or other such extenuating circumstances), how can the data be recovered? Is it even possible? How can I filter items with a certain enchantement? I am trying to build a custom Adventure Island. At this moment I am trying to limit the allowed items on this island. I'm trying to do this by filtering on a certain enchantment which is not item-specific.  For example.   When you want to filter an wooden sword with a custom name, you use this command:  /testfor @p[r=5] {Inventory:[{tag:{display:{Name:"Custom Sword"}}}]} &lt;   When you want to filter a wooden sword with a custom name and specific enchantement, you can use:  /testfor @p[r=5] {Inventory:[{tag:{display:{Name:"Custom Sword"},ench:[{id:16,lvl:1}]}}]} &lt;   But how can I filter on items with a specific enchantment on ANY item? I tried:  /testfor @p[r=5] {Inventory:[{tag:{ench:[{id:16,lvl:1}]}}]} &lt;   But this ain't work. Does anyone know how to solve this issue? doesn't has to /have to This question is a  of the common question asking for calculus references. It is here to  away the repetition, and give a canonical resource for calculus references.      I'm looking for a resources to learn single-variable calculus. Encouraging users to create an account (and keep it) UV coordinates on a deformed plane I added a plane to a scene, subdivided it, and deformed it with proportional editing:    I'd like to UV unwrap this plane, making the mapping what the would have been without the edit mode deformations. In other words, I'd like my UV map to look like a square grid.  Is it possible to UV map this deformed plane to a square grid? Or do I need to start from scratch, and make sure I unwrap it before I do the edits? Calculating the longest distance within polygon in QGIS I want to calculate the "diameter" of polygons in QGIS.  The "diameter" defined as the distance between the two most distant points of the polygon.  I couldn't find a fitting solution in the field calculator. Maybe you have some ideas? Adding user to a group - Why had to reboot? I was not able to access the VirtualBox shared folder, so I made the user part of the vboxsf group. But, still not able to access it. Rebooting the guest resolved the problem. Is it a bug? A reboot is not required to add a user to a group.   sudo usermod -a -G vboxsf praveensripati   There was similar query .  I am using 11.10 and don't remember seeing similar behavior in 11.04. What happens if my order exceeds the bid or ask sizes? What will happen if my order exceeds the bid or ask size? For example, if the bid or ask is 100 shares, but I want to buy 100,000 shares, is it possible to do so? Use variable with TOP in select statement in SQL Server without making it dynamic