The title is basically my question. Is Fashionable for views on all questions asked during Winter Bash on all sites or on just one site?  It has an explanation of:     get over 9,000 combined total views on all questions that you asked during Winter Bash   But that doesn't get me anywhere with what I am asking.
The Winter Bash is back and the hats are listed below.  As always, there are only two answers: one for the secret hats, and one for the regular hats. The secret hat list will be updated as we learn them.  Only edit the secret hat answer with definitive and correct triggers. This is not the place to post guesses.    If you'd like to discuss Winter Bash, hats or just have a question about the WB please come over to the .  Please keep the comments here clean. As always comments are not meant for discussion, conversation, "I just got hat X", etc use the  for that (the remaining meta mods will periodically clean the comments). I know you are excited you just got a secret hat, but please instead of posting a comment come over to the  and tell us all there.  Provided that "It's important to know your history... in more ways than one"  again this year, here are the hats from prior years:
Strange result when removing item from a list while iterating over it Does a polymorphed creature remember who his friends are? This question is about an efficient way to compute principal components.   Many texts on linear PCA advocate using singular-value decomposition of the casewise data. That is, if we have data $\bf X$ and want to replace the variables (its columns) by principal components, we do SVD: $\bf X=USV'$, singular values (sq. roots of the eigenvalues) occupying the main diagonal of $\bf S$, right eigenvectors $\bf V$ are the orthogonal rotation matrix of axes-variables into axes-components, left eigenvectors $\bf U$ are like $\bf V$, only for cases. We can then compute component values as $ \bf C=XV=US$. Another way to do PCA of variables is via decomposition of $\bf R=X'X$ square matrix (i.e. $\bf R$  correlations or covariances etc., between the variables ). The decomposition may be eigen-decomposition or singular-value decomposition: with square symmetric positive semidefinite matrix, they will give the same result $\bf R=VLV'$ with eigenvalues as the diagonal of $\bf L$, and $\bf V$ as described earlier. Component values will be $\bf C=XV$.   Now, my question: if data $\bf X$ is a big matrix, and number of cases is (which is often a case) much greater than the number of variables, then way (1) is expected to be much slower than way (2), because way (1) applies a quite expensive algorithm (such as SVD) to a big matrix; it computes and stores huge matrix $\bf U$ which we really doesn't need in our case (the PCA of variables). If so, then why so many texbooks seem to advocate or just mention only way (1)? Maybe it is efficient and I'm missing something? How can I fix apt error "W: Target Packages ... is configured multiple times"? Script to Notify me when something happens on a shared directory The situation is:  I have a shared directories from many other machines where other users work on.  I need to be notified whenever a user create, modify or delete a directory or file from his local directory which I share using smb...  It looks like the folder actions in the MAC systems..  Is there a software that do that?!  If there is no such application, any help in writing a script for that is appreciated..  Thanks in advanced... What is the difference between "INNER JOIN" and "OUTER JOIN"? Also how do LEFT JOIN, RIGHT JOIN and FULL JOIN fit in? Is there a way to make rigid body interact with softbody physics? I'm trying to have a surface with soft body hold obects that are falling on it with rigid body physics, but for some reason, no what matter what mass I give it, the objects just fall trough the softbody enabled surface.  Is there a toggle or a value I need to change to make them stay there? A question of Euclidean domain Leave the door open vs Leave the door opened Is there any subtle difference between:   We need to carry in some stuff so open the door and leave it open. We need to carry in some stuff so open the door and leave it opened.   I mean "leave it like that (in that state)". Set the Max depth parameter of both the Reflection and Refraction roll-out to 10. I am not sure whether roll-out should be plural or not in this particular case. Consider the atomic spectrum (absorption) of hydrogen.     The Bohr's model postulates that there are only certain fixed orbits allowed in the atom. An atom will only be excited to a higher orbit, if it is supplied with light that precisely matches the difference in energies between the two orbits.   But how precise does 'precisely' mean. Of course, if we need energy $E$ to excite the electron to a higher energy level, and I supply a photon with just $E/2$ I would expect nothing to happen (since the electron cannot occupy an orbit between the allowed ones). But what if I supplied a photon with energy $0.99E$, or $1.0001E$ or some such number. What will happen then?  I think that the electron should still undergo excitation precisely because the lines we observe in the line spectrum have some thickness. Which means that for a given transition, the atom absorbs frequencies in a certain range.   Is my reasoning correct? If not, why? How does Bohr's model explain this? How about modern theory?   If I'm right, what is the range of values that an atom can 'accept' for a given transition? What happens to water level when ice XII melts? There exists this famous idea that if all floating icebergs melt, water level will stay the same (because the water replaced by ice is the volume of the melted ice). Now,   Is this always so, if you allow more exotic forms of ice (take e.g. ice XII with density 1.29) ? Is this always so on/in earth ?   EDIT:  I was looking a possibility that you would have water as a liquid that contains pieces of water as a solid. No land is assumed to exist here. "Ice" is always floating or sunken(if possible).  To reformulate, can Ice be sunken in water in any circumstance (pressure, temperature)?  EDIT 2:  Wikipedia: "Ice VII has a density of about 1.65 g cm-3 (at 2.5 GPa and 25°C)".   And water as an incompressible liquid has a density of 1 g cm-3. This means that ice VII is at the bottom of the "lake" and will expand when it melts. Is this true? And are there environments in earth where this (or similar) can happen? As far as I know, the diamond symbol is given to the folks who  are the community elected moderators, for example,  are employees of the Stack Exchange, Inc., for example,   In those regards,  is neither a , nor is he a part of the  since March 1st, 2012. So my question is, other than the fact that he is the , is there any other reason why he still has the diamond symbol next to his name and whether he can still exercise his moderation abilities? :) Note: I do not have any problems with him having the Diamond Symbol. I just wanted to know the reason and whether he still has those privileges or not. In fact, I'd be very happy to know that he still has those privileges because, you know, he knows the site, the Best. :) Note: as of October 2017, . How can i make my Java Swing GUI Components [Right To Left] for Arabic language from NetBeans Desktop Application? How to find the center of an ellipse? How do I unload (reload) a Python module? I have a long-running Python server and would like to be able to upgrade a service without restarting the server. What's the best way do do this?  if foo.py has changed:     unimport foo  &lt;-- How do I do this?     import foo     myfoo = foo.Foo() I have a Windows XP box (NTFS filesystem) on which I found a file named NUL. I have not been able to remove this file in any usual way. The file appears to be owned by Administrator in the SYSTEM group, unlike any other file in the same directory (the other files are owned by my user id).  How do I get rid of this file? Where did it come from? Using Static Variables in a Custom Module I'm trying to define a static variable for use in my custom module. I want it to let me pass a number from function to function. I'm using drupal_static() but I can't get it to work. How do I do this?  This is the code I'm using to define my static variable.  $var = &amp;drupal_static(__FUNCTION__); if (!isset($var)) {   // generate contents of static variable   $var = '8'; } return $var;   I've tried putting it in a custom module.    function viewusercontact_locateuser($value, $key, &amp;$counter) {    global $user;     /**********In here***********/     if ($value['uid'] == $user-&gt;uid) {       ........    } }   I can't seem to get it to work. What am I doing wrong?  (I got my code from the following guides) I've set up the physics of a swinging wrecking ball and set the animation to run for 240 frames.  This was not long enough for the entire "swing" of the ball-and-chain.   I'm unable to reset the timeline, but I can set the end frame to (say) 1000 frames, but when I try to play the animation, the animation progress halts at frame 240 and I cannot get it to go any further.   There are no markers or keyframes in the timeline.  What should I do to "force reset" the animation-timeline, to allow changes to the length? Is it correct to say "12:00am"? I've read in various places the first minute of a day described as 12:00am.  Now, whilst I personally prefer to use 24h clock notation and therefore don't have this problem as I can simply describe this minute as 00:00, how is one supposed to express this time using am/pm notation?  Is 00:00am common (strange because there is no 00:00pm), or is the least-bad way to say 12:00am (strange IMHO because it seems to imply that the previous hour was 11:00am when it was actually 11:00pm)?