Related questions:   .       Dictionary aids:  -  -     Right after a new user registers for this site (and/or related ones), such user is quite limited in what he/she can do on these sites. I think I understand why. Such user cannot comment anywhere because the required privilege was not earned yet.  So such user needs to start "doing things on SE" to "earn" the required (eg 50) points somehow. But with all imposed limitations for such user, it is quite frustrating. Here are some examples of what it is like to be a :   If such user finds a question and wants to ask a related question, then he/she typically wonders about one or more of these possible questions (pretty sure there are other questions ...):   Should I post an answer? Am I actually allowed (already) to post an answer (maybe it requires a privilege I do not have yet)? I want to answer but I don't know for sure how to do actually so (and I want to avoid making a bad first impression). If I post an answer it might not comply with the guidelines (I want to prevent being perceived as not following them, as illustrated also by the rather scary ""). I don't know what could happen (I'm too new to realise / predict the possible consequences, due to lack of experience with how this community typically reacts).  Comments are disabled (see above), so that's not an option 'yet'. Sure there is a badge awarded for 'visiting' the  ( ...), but what does that really mean? How about making that specific batch (way) more difficult for it to be rewarded? Note to myself: did anybody ever file a  about that? Thanks  for suggesting visiting the help center as a possible (partial?) remedy.   So it appears that if such user doesn't 'answer' the question, he/she will not get any closer to being able to get out of what appears to be a newbie loop.  My Question: How can such user get more information, or just suggest something to the original poster (Note: often abbreviated as OP-er, whereas OP=Original Post ...)?  Credits to all participants for teaching/suggesting me (sometimes quite challenging ...), Especially to "James", a real SE "mentor". Start 'lurking' via his profile page to learn 'AbitMORE' and consider voting (up!) any of his impressive questions, and answers.  Notes to myself (haven't found a feature, or earned some privilege, to make it invisible ...): I'm the OP of this question, and " learned some other lesson" recently about the "power" that an OP seems to have regarding some hidden feature that is NOT documented (yet) in the official help pages ... at least I have not found such documentation yet. Todos:    File a  about it (or is it a ?) ... What are "my" options if I would want to "overrule" the voting to consider this question as a duplicate (I do not question that anymore, but just want to learn about such options). If I can't figure it out, I'll probably "ask" people like ... James! What's a 'catch 22' ? I do know what "lesson 101" is ... that doesn't help of course. It's tough to be a non-native-english SE-er ... awel, "merci mes amis"!
I have been reading Stack Exchange for years - mostly not logged in, and have never posted (this is my first). I'm simply not very talkative, and very good at googling.  Recently a few occasions have come up when I've wanted to comment on a question.  I wanted either to ask for, or provide, clarification which did not warrant a new answer.  How do I gain enough reputation to comment without:   asking questions which have already been answered or that I can figure out on my own, or posting my comment like as an answer (i.e. being  rude)?
Why is a Hyperplane called a "Hyper"plane? I just had this curious question. In other fields, the word "hyper" is actually used to refer to something which is "over; beyond; above" as defined by Google. An example of such terms would be Hyperglycaemia, defined by Wikipedia as:     a condition in which an excessive amount of glucose circulates in the blood plasma.   Or Hypersonic, defined by Google as:     relating to speeds of more than five times the speed of sound.   So, my question is, what would be the motive to give a Hyperplane such a name when it is defined as :     a subspace of one dimension less than its ambient space The Most Efficient Way To Find Top K Frequent Words In A Big Word Sequence Input: A positive integer K and a big text. The text can actually be viewed as word sequence. So we don't have to worry about how to break down it into word sequence. Output: The most frequent K words in the text.  My thinking is like this.    use a Hash table to record all words' frequency while traverse the whole word sequence. In this phase, the key is "word" and the value is "word-frequency". This takes O(n) time.  sort the (word, word-frequency) pair; and the key is "word-frequency". This takes O(n*lg(n)) time with normal sorting algorithm.  After sorting, we just take the first K words. This takes O(K) time.    To summarize, the total time is O(n+nlg(n)+K)， Since K is surely smaller than N, so it is actually O(nlg(n)).  We can improve this. Actually, we just want top K words. Other words' frequency is not concern for us. So, we can use "partial Heap sorting". For step 2) and 3), we don't just do sorting. Instead, we change it to be  2') build a heap of (word, word-frequency) pair with "word-frequency" as key. It takes O(n) time to build a heap;  3') extract top K words from the heap. Each extraction is O(lg(n)). So, total time is O(k*lg(n)).  To summarize, this solution cost time O(n+k*lg(n)).  This is just my thought. I haven't find out way to improve step 1). I Hope some Information Retrieval experts can shed more light on this question. I'm using Ubuntu 16.04 and there's no fglrx! Let $A \in {M_n}$ is nonsingular and each eigenvalue of $A$ is either $+1$ or $-1$.Why $A$ is similar to ${A^{ - 1}}$? Color gradient for bars in pgfplots I want that each bar in my diagram has a color gradient from black to white (from left to the right). However, for the following code, the gradient exists for the entire diagram such that the left bar is black, the middle one is gray, and the right one is white.   \documentclass{report}  \usepackage{pgfplots}   \begin{document}  \begin{tikzpicture}      \begin{axis}[ybar]          \addplot[left color=black,right color=white] coordinates {(1,2) (2,3) (3,4)};      \end{axis}  \end{tikzpicture}  \end{document} When estimating variance, why do unbiased estimators divide by n-1 yet maximum likelihood estimates divide by n? I am totally confused: On the one hand you can read all kinds of explanations why you have to divide by n-1 to get an unbiased estimator for the (unknown) population variance (degrees of freedom, not defined for sample size 1 etc.) - see e.g.  or .  On the other hand when it comes to variance estimation of a supposed normal distribution all of this doesn't seem to be true anymore. There it is said that the maximum likelihood estimator for variance includes only a division by n - see e.g. .  Now, can anyone please enlighten me why it is true here but not there? I mean normality is what most models boil down to (not least due to the ). So is the choice "division by n" yet the best choice for finding the best estimation for the true population variance after all?!? What is the difference between AOSP and AOKP? Confirmation that someone is listening to another person's speech When someone is telling you a very long and detailed story he usually wants to hear some "confirmations" (or response) that you are listening to his story. In Russian we often use something like "tak" (which has a meaning of "ok" and "well, proceed further"), "a-ha" or "uh-huh".  What word serves the same purpose in English and American English? As of today I only knew about ubuntu-bug which I could use to report bugs about a specific program. But now I learned about apport-collect and apport-bug which basically are:  apport-bug - Reports problems to launchpad using Apport to collect a lot of information about your system to help the developers fix the problem and avoid unnecessary questions and answers.  apport-collect - Works as apport-bug but it send the information to an already existing bug report. In my case it was apport-collect 1060268 Thanks to Brad Figg in Launchpad.  Are there any other tools to report bugs? How do I print all lines of a file with duplicate values in a certain column Given a file like this:  1,768,12,46576457,7898 1,123,435,134,146 2,345,6756856,12312,1311 5,234,567465,12341,1341 1,3245,4356345,2442,13 9,423,2342,121,463 9,989,342,121,1212   I would like to list all rows (in bash terminal) such that the value in column 1 appears at least twice (in column 1). The result should be  1,768,12,46576457,7898 1,123,435,134,146 1,3245,4356345,2442,13 9,423,2342,121,463 9,989,342,121,1212 How can I visualize or simulate the effect of different focal lengths? I have seen many camera review sites illustrate the effect of using different focal lengths on the same photograph using frames. There are also similar illustrations to compare different sensors (). I find this kind of visualization to be very useful in comparing the actual effect of the longer focal length\different sensor size. Of course the ability to do a wider focal length visualization would also be equally useful, but that's not possible.  Is there any ready-made software or plugin that enables this? If not, is there any simple technique to visualize the effect of longer focal lengths on an image (one would of course have to use the zoom information in the image EXIF data to accurately represent this)? All I can think of is to use some trigonometry to do the necessary calculations for the frame sizes for cropping. Return more than 2000 records (SOQL) I'm trying to retrieve a list of Account objects from Salesforce using SOQL. Originally my query was this:  var result = service.query("SELECT Id, Name, RecordTypeId FROM Account"); return result.records.Select(record =&gt; record as Account).ToList();   However this only returns a maximum of 2,000 records and I have over that which I need to be returned by this query. After some digging around I found an example in Java which loops over the SOQL query which will allow a maximum of 10,000 records to be returned. I tried to replicate this in C# but it differs slightly, here is what I have now:  var accounts = new List&lt;Account&gt;(); foreach (Account account in service.query("SELECT Id, Name, Composer_ID__c, RecordTypeId FROM Account").records)     accounts.Add(account);  return accounts;   However this still only returns a maximum of 2,000 records. How can I return more than 2,000 records by querying Account? How to combine low sample renders? How to sanity check a date in Java I find it curious that the most obvious way to create Date objects in Java has been deprecated and appears to have been "substituted" with a not so obvious to use lenient calendar.  How do you check that a date, given as a combination of day, month, and year, is a valid date?  For instance, 2008-02-31 (as in yyyy-mm-dd) would be an invalid date. Hogsmeade has a lot of individuals who live there, and it has the distinction of being the only non-muggle community in the UK. Are there any students at Hogwarts who live there during the summer?  I ask because  explicitly says that students must ride the train or not go to the school at all, which seems silly for someone who already lives at the destination.     Many pure-blood families were outraged at the idea of their children using Muggle transport, which they claimed was unsafe, insanitary and demeaning; however, as the Ministry decreed that students either rode the train or did not attend school, the objections were swiftly silenced. What does it mean if a Python object is "subscriptable" or not? Few days back I have installed ecryptfs, created a private directory using it. Now my Ubuntu login became super slow. I have tried removing ecryptfs from Synaptic. I found It, it can not be deleted that way. Somewhere I have read about this command  ecryptfs-setup-private --undo   But this command displays a rather confusing list of commands on terminal. I don't want to mess up my installation, neither want to loose my administrator account.  Now my question is, how can I safely remove /home/user/Private (.Private) and remove ecryptfs encryption ? Configuring dpkg stops processing when calling an HTTP request to Adobe Flash Player Is there a way to input particular sections of source code using \lstinputlisting (from the listings package) in a flexible way?  It's possible to use the firstline and lastline options to input particular line ranges, but this isn't robust to changes to the source file.  For example, suppose that the input source file is:  int square(int x) {   return x * x; }  int cube(int x) {   return x * x * x; }   In my LaTeX document, I can include the cube procedure using the command \lstinputlisting[firstline=5,lastline=7]{source.c}.  But suppose I later decide to rewrite the cube procedure.  The input source file becomes:  int square(int x) {   return x * x; }  int cube(int x) {   int x2;   x2 = square(x);   return x * x2; }   Now my LaTeX document will not show the final two lines of cube because the listing uses only lines 5-7.  I could manually update the line range, but this is tedious and error-prone.  Is there a way to mark sections of source code with some kind of label so that the listing will be robust to these sorts of changes?  For instance, perhaps the input source file would be something like  int square(int x) {   return x * x; }  /**\beginlabel{lst:cube} **/ int cube(int x) {   int x2;   x2 = square(x);   return x * x2; } /**\endlabel{lst:cube} **/   so that I could use something like \lstinputlisting[lines=lst:cube]{source.c} to include the section that I want and remain robust to changes.  I am open to using other packages for source code listings (e.g., minted) if helpful. Can anyone recommend a simple API that will allow me to use read a CSV input file, do some simple transformations, and then write it.  A quick google has found  which looks promising.  I just wanted to check what others are using before I couple myself to this API.