On several occasions I have seen answers that belong to a list of users (abstract or real) like :  15 revs, 9 users 85% Robert Cartaino   When  owns something, no reputation point changes occur, but in this particular case, there are only real users that "own" the answer.  How are reputation points computed if such an answer is upvoted or downvoted?  Answer based on comment: "Voting on a community wiki post (up or down) does not affect any user's reputation."
Some questions and answers are marked Community Wiki and are owned by a community wiki user:  (In fact, this very question is one of them)  Why have Community Wiki posts? How do Community Wiki posts work? How does a post become a Community Wiki post? How can the Community Wiki status be removed from a post? How can I find Community Wiki posts?
I want to say "someone (or something) intends to help, but instead it makes things worse". Is there any succinct expression or phrase for this?  Thanks. Inadvertent use of = instead of == It seems that   if (x=y) { .... }   instead of  if (x==y) { ... }    is a root of many evils.  Why don't all compilers mark it as error instead of a configurable warning?  I'm interested in finding out cases where the construct if (x=y) is useful. How does the Comma Operator work How does the comma operator work in C++?  For instance, if I do:  a = b, c;     Does a end up equaling b or c?   (Yes, I know this is easy to test - just documenting on here for someone to find the answer quickly.)  Update:  This question has exposed a nuance when using the comma operator.  Just to document this:  a = b, c;    // a is set to the value of b!  a = (b, c);  // a is set to the value of c!   This question was actually inspired by a typo in code.  What was intended to be  a = b; c = d;   Turned into  a = b,    //  &lt;-  Note comma typo! c = d; Geometric interpretation of the multiplication of complex numbers? I've always been taught that one way to look at complex numbers is as a Cartesian space, where the real part is the $x$ component and the imaginary part is the $y$ component.  In this sense, these complex numbers are like vectors, and they can be added geometrically like normal vectors can.  However, is there a geometric interpretation for the multiplication of two complex numbers?  I tried out two test ones, $3+i$ and $-2+3i$, which multiply to $-9+7i$.  But no geometrical significance seems to be found.  Is there a geometric significance for the multiplication of complex numbers? give a variable to an operator For a workflow tool I made a panel in which it displays each separate library that is linked in my file. For each library I want to add some buttons that does stuff to the library in question.  So in this example I have my panel which shows for example 2 libraries and for each one it creates a "reload" button.  Now my question is.. How do I make it so the reload button only reloads the library I want to reload? I would probably have to give the button an id or something so it knows for which library it was created...  my code so far:  import bpy  libs = bpy.data.libraries  class Reloadlib(bpy.types.Operator):     """Reloads the current Library"""     bl_idname = "my.reload_lib"     bl_label = "Reload"      def execute(self, context):         libs[?????].reload()         self.report({'INFO'}, 'Reloading ' + libs[?????].name)         return {'FINISHED'}  class LibPanel(bpy.types.Panel):     """Creates a Panel in the scene context of the properties editor"""     bl_label = "Scene Libraries"     bl_idname = "SCENE_PT_layout"     bl_space_type = 'PROPERTIES'     bl_region_type = 'WINDOW'     bl_context = "scene"      def draw(self, context):         layout = self.layout         scene = context.scene         layout.label(text="Libraries:")          for i in libs:             layout.label(text= i.name.replace(".blend",""))             row = layout.row()             sub = row.row()             sub.operator("my.reload_xref", icon = "FILE_REFRESH")  def register():     bpy.utils.register_class(Reloadlib)     bpy.utils.register_class(LibPanel)  def unregister():     bpy.utils.unregister_class(Reloadlib)     bpy.utils.unregister_class(LibPanel)  if __name__ == "__main__":     register()   Where the question marks are is where I should be able to make the difference between the first [0] or second [1] library in the libs[] array.  In future I would also like to ad an 'open' and an 'unlink' button for each library so I can make changes to the other file. But this works by the same principle as the reload button. Where is the default folder for Apps? I am relatively new to the linux world. I use OSX at home and Windows at work. In those worlds, there is a default folder for applications (C:\Program Files, /Applications). Is there any such directory in Ubuntu?   I understand that this is not very important and any location in the file system should be ok, but was just wondering whether there are such standard locations (I think there would be one). For instance where is Firefox or Libre Office (that are installed by default)?  Got this question when I was trying to install eclipse. Downloaded the zip, and was wondering... How to preserve detail when downscaling scanned photos? I'm mixing analog with digital photography — I tend to take better photos when I can't look at a small digital screen, unconsciously forcing me to take the picture before I shoot instead of checking afterwards if it succeeded. I also like the grain film gives me.  However, most shots aren't worth spending much time in the darkroom, and scanning them is a lot faster. I'm wondering how best to convert the film to digital.  Scanning at lower than maximum (non-interpolated) resolution of my image scanner tends to exaggerate the contrast of the grain and screw up the mid-tones because of that.1 On the other hand, the resulting size of the scans are major overkill in most cases (I don't print them at A0 size), so I want to downscale the pictures. However, the grain confuses most methods and results in loss of detail and/or loss of the characteristic grain. For example, bicubic sharper tends to result in a "bigger" grain than the original. Now, the best compromise I've found so far is simply using bilinear interpolation, but I doubt that this is the best method to preserve both overall details and the look of the grain.  In short: when processing the scanned negative, how do I "best" preserve both image quality and the characteristic look of the grain?   As Stan Rogers pointed out below, there's a difference between truly scanning the grain of the film, and scanning the "grainy" character of film at lower resolutions. This question is about the latter; Stan Rogers explains how to do the first.  I'm looking for alternatives to the standard Photoshop options to try out, and reasons for each. Is the fact that every film has a different grain characteristic a problem? Are customized advanced noise reduction methods perhaps an option?  1. I'm using a Minolta DiMAGE Scan Elite 5400, using the software provided by Minolta.  As requested, here is a scanned picture with different resize methods. Just scanned this, scanning a B&amp;W negative to get better tonality range. I turned off grain dissolver, automatic dust and scratch removal, etc, for obvious reasons. On the right the pictures are upscaled again with Nearest Neighbor. I set the 8 bit scan to 16 bits before downscaling, assuming it reduces risks of banding if I choose to mess with curves, channel mixers, etc. No other modifications (usually I first retouch dust &amp; scratches, and in the end channel mix the picture to B&amp;W, then switch to 8 bits again). Teleporting a player from the overworld to the end Where can I find a complete reference for the $PS1 variable? The default PS1 variable on my machine (Kubuntu 13.10) is this:  \[\e]0;\u@\h: \w\a\]${debian_chroot:+($debian_chroot)}\u@\h:\w\$   I'm looking for a reference for how the $PS1 variable works that, at a minimum, allows me to understand the above PS1 variable. pgrouting unexpected output How can I set the value of auto property backing fields in a struct constructor? Given a struct like this:  public struct SomeStruct {     public SomeStruct(String stringProperty, Int32 intProperty)     {         this.StringProperty = stringProperty;         this.IntProperty = intProperty;     }      public String StringProperty { get; set; }     public Int32 IntProperty { get; set; } }   Of course, a compiler error is generated that reads The 'this' object cannot be used before all of its fields are assigned to.  Is there a way to assign values to the backing fields or the properties themselves, or do I have to implement properties the old-fashioned way with my own explicit backing fields? Enable disk encryption after installation What is the best choice for .NET inter-process communication? data.table and table unexpected behavior Offer a network-wide newsletter Eclipse issues warnings when a serialVersionUID is missing.       The serializable class Foo does not declare a static final   serialVersionUID field of type long   What is serialVersionUID and why is it important?  Please show an example where missing serialVersionUID will cause a problem. Iterating through columns in table using ModelBuilder? I am unable to find any info on how to use ModelBuilder to run a certain spatial analysis function on each column in a table.  I have a table to sample locations and at each location there are a series of measures (e.g. temperature, flow rate, number of certain species).  For each of those attributes (columns in the table), I was to run the IDW function from the surface tools.  This would be easy if I had each attribute in a separate shp/feature class, but not very efficient.  I tried Iterate Feature Selection, but was unable to pass the field name as the Z value in the IDW function.  This is for ArcGIS 10.1 (Basic and Spatial Analyst license) How do I explain current and voltage to a lay man? A man asked me this question in suburban train when I told him that I am an electrical engineer. Of course I replied him that current is the flow of electrons and in order for the current to flow there should be a potential difference between them. But the man didn't know what electron or potential difference was either. How do I pronounce "ratio 1:1"? How do I pronounce "ratio 1:1"?  Should I pronounce it "ratio 1 to 1"? Recent fluid-mechanical experiments by the groups of Couder in Paris and Bush at MIT, mimic a surprisingly wide range of quantum effects. The essential ingredient of these fluid-mechanical systems is a background or pilot-wave that guides the droplets.  Now, surprisingly, a simple analysis of a Bell-type experiment shows that, in the presence of a background field, one of the premises of the Bell inequality, namely measurement independence (MI), is violated. See the paper  (available ). Therefore such classical droplet experiments could violate a Bell inequality. More importantly, if this analysis is correct, background-based hidden-variable theories are admissible, even if they are local (in the sense of ‘involving only (sub)luminal interactions’) and even if they are compatible with free will.   My question: to me the analysis seems fully sound, but maybe there is still an unphysical hypothesis that slipped in ?