Is it legal to make a character very similar/exact from other game? E.g. take characters from Team Fortress 2 game, remake them in pixel art and use it in my game, but just change their names(with an intent to make money).  Would I get in trouble?

Most games build on other games' successes and many are downright clones. Where is the limit of imitation before legal issues come into play? Is it down to literary or graphic work like characters and storyline that cause legal problems, or can someone actually claim to own gameplay mechanics?  There are so many similar clone games out there that the rules are probably very slack or nonexistent, but I'd like to hear the views of more experienced developers / designers.


I understand that buffer overflows are more vulnerable in languages like C and C++, but a language like Java or C# that always checks for out-of-bounds exceptions... are buffer overflows still possible?

Does Java have buffer overflows? If yes can you give me scenarios?


which tutorials can get me to animate my very first 3D animation.  The way I learn is if I could find a video to follow along that will allow me to be successful at getting a ball to bounce or getting any basic object to become animated...by the end of the video.  A true bona fide quick start.  I have watched several youtube tutorials that claim to be for absolute beginners but I just need to have one very simple success under my belt and then my mind can rest at easing knowing that it's possible for me to animate an object.  Right now it seems impossible that I will ever be able to animate an object.

Since asking for tutorials, videos, resources, links to other content or downloads is considered off topic here, this is a specifically created Community Wiki which gathers resources for Blender and it has been approved by the .  Just write in the appropriate answer/section. If you have concerns, questions, post a  question, so we don't clutter the comments, but you can link your meta question from the comments.  Questions regarding such resources are not allowed anymore, except for very specific and on topic requests (ask on  if you're unsure about your question). Follow the instructions made in the question about how to post, what can be posted, etc.  Learning             Assets    (also see: )   Reference Images/Blueprints (also see: )    Tools    (also see: )      Other   Special Interest ()     Also see the .


How can we prove that every hyperplane (a subspace of dimension $n-1$) is a null space of a linear functional? I don't know how to prove this.  I tried a lot, but something is missing.

How do I prove that a subspace of a vector space $X$ is the null space of some linear functional on $X$? Say $\dim(X) = n$ and $Z$ is the subspace and $\dim(Z)=n-1$. Further, how to show that the functional is always uniquely determined to within a scalar multiple?  I'm having a difficult time coming up with a functional $f$ and don't understand how I would have to go about proving it unique to within a scalar multiple. Any help will be greatly appreciated.


Ubuntu 17.10 comes with modified gnome. I would rather use vanilla gnome the way i like it.  How can i install it?

Some people (me) would prefer the straight GNOME experience as opposed to the Unity style desktop offered in Ubuntu 17.10.  How can I get the standard GNOME desktop and interface?


I failed to complete my research project (undergraduate) in the time I said I would, because of overconfidence. It seemed like a quite simple project to both me and my advisor initially considering that it was very similar to a project another student of his had worked on, however for some reason (much of the blame is my own) I ran into countless difficulties and now I will not finish in time. How do I get past something like this? I do not know how to continue after such disappointment.  As an addendum: How does one develop an "aptitude" for research? I would like to go to graduate school, but a lot of the advice hinges on whether one not only enjoys but has an "aptitude" for research. Based on my minimal accomplishments this year, it seems clear that I do not currently have an aptitude for research. Can I ever develop such an aptitude?  Edit: I do not feel that this question is a duplicate. This is about UNDERGRADUATE research. Undergraduates have a very different situation - I cannot simply take another week and work on it as the semester will end soon, after which I will undertake an internship, and I have commitments to my courses and other things.  Also, this is not a case of me getting data that don't support my hypothesis - I do not have any data. Or rather, I have data, but it is meaningless until I finish my current project. Which I was supposed to do today.

I am a third year (starting fourth year in the fall) PhD student in mathematics. I've passed all qualifying exams and am currently doing research. As far as I can tell, I am not doing poorly. I have the good fortune of having a great advisor, being in a very supportive department, and having friends and family who genuinely care about my success.   The fact is research is hard. It appears to consist primarily of staring at a problem for days and days and days without getting anywhere. Sometimes, rarely, I do figure something out and that feels wonderful, but the overwhelming majority of my time appears to be spent banging my head against a mostly figurative wall. I am not complaining about the material being hard, and I am not averse to putting in hard work, but I get frequently discouraged when I realize the vast volumes of mathematics that I yet know nothing about (and probably never will). It's very hard to quantify progress - in particular, there are too few tangible returns after too many hours worked. I find myself thinking along the lines of "Oh, if only someone actually smart were thinking about this problem they would have solved it in moments" and so on.   I've talked about this to some number of people; here is some advice I have received:   Take a day off. Putting in hours upon hours of trying things doesn't magically lead to a solution, particularly if the brain is tired and just wants to sleep. Have a hobby. Since math research doesn't exactly provide instant gratification, a hobby might provide some instead.  Talk to other graduate students. Realize that many graduate students go through this.   I'm interested to know how other folks have dealt with being discouraged as a graduate student. Does it get better with time and experience? Is this a sign that research is not for me and that I should seriously consider a life outside academia?


So I noticed that my compainion had removed all his power armour peices, although he was still wearing the suit - turned out they'd all been damaged until unusable :(  How can I repair them, do I need to make him climb out (and if so, how?) or can I some how repair them while he's still holding each item?

After I read that companions don't drain the fusion core of a Power Armor when wearing it, I decided to try giving my armor to Nick so I'll always have it close by if I need it.  But I was wondering if there are any other drawbacks to that. For example, does the Armor get damaged or destroyed when the companion is under fire?


I am having an issue,  My log file on a large database keeps getting large. Its set to simple recovery and right now the log file is 40GB big.  It got to the stage where its filled up the HDD, and when I try and delte older rows in the databse, it tries to record this to the log file, and it cant cause the hdd is full so it cant delete the entry.  So how can I a?  Scrap / delete / empty the current log file, i have no need for the data in it.  or b:  Delete from from the table in a manner that doesn't log it in the log file?  I have tried:  DBCC SHRINKFILE(FSK_LoggingServer__log, 200); GO   but it returns this:     bdid, FieldId, CurrentSize, MinimumSize, UsedPages, EstimatedPages 32  2   4292352 512 4292352 512   and it does not shrink the file.

I'm not a SQL expert, and I'm reminded of the fact every time I need to do something beyond the basics. I have a test database that is not large in size, but the transaction log definitely is. How do I clear out the transaction log?


I installed Ubuntu out of a USB stick and created a dual boot in my windows 8 computer.  Now I was informed to use another computer for Ubuntu's purpose and I want to undo what I've done.  Is there a quick way to do it without hurting my windows 8 environment?

I have absolutely no experience with Linux, and I desperately need to get my computer back up and running again with Windows.  How do I remove Ubuntu and reinstall Windows?    Editor's note: many of the answers are about removing Ubuntu from dual-boot but keeping Windows (which is a bit complicated), while other answers are about removing Ubuntu from single-boot (which is easy: basically just format the disk while installing Windows). The question as written is ambiguous between dual-boot or single-boot.


What questions should be asked on which StackOverflow sister sites?

There seems to be more than a few computer science/programming Stack Exchange networks (is that the correct term?). Stack Overflow, being the first, has by far the most users, questions, and answers.  What is the reasoning for creating the others, and are there clear guidelines for which kinds of questions should be posted? I can see a large amount of potential overflow, many cases of people not getting a good answer to their question, because the person who has the answer isn't browsing that particular network at the moment.  I understand that they were probably created for organizational purposes, but wouldn't it almost make more sense to just have them as categories under Stack Overflow, keep them separated but still connected, instead of making people have to create multiple 'account's, one for each network?  I am sure there was a very good reason to break them up, but as someone that is new to SE, it can be somewhat intimidating to decide which one to post in to ensure you get a good answer. For example, if I am a computer science student, my first instinct might to be to post in the computer science network, until I see that it literally has 1% of the users as the Stack Overflow network, which still seems to be for programming/computer science related questions.  So my second instinct would then to be to post it into the Stack Overflow site on the basis that I have a significantly higher chance of my question being seen and getting a good answer. Then I notice that there is also a 'programmers' network, and I don't even begin to know where that fits in. I, and I am assuming most people, will probably just post on Stack Overflow to be safe.  My question is, other than the short little description blurb of each one, is there a clear cut set of guidelines which what each network is intended for, what kinds of questions should go to each one, and is anything being done to encourage people to post in these newer, smaller (more specialized?) networks as opposed to just posting in big daddy Stack Overflow?  Now again, this is for computer science/programming/"why isn't this code doing what I want?" related questions, I am not saying that if I had a question about Linux or WordPress or something I would have the same confusion.


I am trying to find a certain string within an array.  This is my code so far:  function getUserName(arrayName){ for (counter = 0 ; counter < arrayName.length ; counter++){     check = arrayName[counter].search("Jon");      if (check != -1){           result = arrayName[counter];     }                    break;   } }      The problem that I am running into is that if there is a name above Jon in the array (e.g Jon_111) the result would be Jon_111 and not Jon   What do I use to tell it to only find and return if it is exactly Jon.

What is the most concise and efficient way to find out if a JavaScript array contains a value? This is the only way I know to do it: function contains(a, obj) {     for (var i = 0; i < a.length; i++) {         if (a[i] === obj) {             return true;         }     }     return false; }  Is there a better and more concise way to accomplish this?


I'll ignore the fact that it isn't obvious what '20190927.6' is from the screenshot (it would be more obvious in the workflow context).   Obviously someone is following the pattern that the primary button should be labelled clearly as the effective outcome - in this case, clicking on the primary button should result in '20190927.6' being cancelled.  They've also included a secondary button which backs out of the process without making changes - labelled 'Cancel'.  Luckily, there's a design convention - so the blue button is probably the primary action, and the grey button is probably the secondary.  What would be a better way to label these buttons?  Given the 'are you sure' question, wouldn't Yes/No buttons be good enough in this instance?

When attempting to cancel a service or setting, "cancel" is the default action. What should the normal "cancel" button be called?  Redbox uses a playful "just kidding", which may not be appropriate in all circumstances.


Infestation is one of the new cantrips from Unearthed Arcana: Starter Spells. Here is the relevant text     The target must succeed on a   Constitution saving throw or take 1d6 piercing   damage. If the target takes any of that damage,   the target moves 5 feet in a random direction.   Roll a d8 for the direction...   Does the target's movement here provoke opportunity attacks from any of my adjacent allies?

If I cause an opponent to leave my reach with an ability, spell, or effect can I use my reaction to take an Opportunity Attack against them?


Here's an interesting question I came across.The person who gave it to me told me that it should not take more than $3$ minutes to solve this question. But I could not find any definite solution :( Maybe you guys could give me some help.Any hints would be appreciated.Here's the question:  Let $f(x)$ be a polynomial with integer coefficients. Suppose for $5$ distinct integers $a_i$, $1\le i\le5$, $f(a_i)=2$. Find an integer b (if it exists) such that f(b) = $9$.

The question that I am trying to answer is :  Suppose is $p(x)$ is a polynomial with integer coefficients. Show that if $p(a) = 1$ for some integer a then $p(x)$ has at most two integer roots.  I have no idea how to get started. Any help would be awesome!


Lets say we have a string in java. Can we compare this string to "" using the ==? For example:  String myString = ""; if(myString == "");

I have a question about comparing a string with the empty string in Java. Is there a difference, if I compare a string with the empty string with == or equals? For example:  String s1 = "hi";  if (s1 == "")   or   if (s1.equals(""))    I know that one should compare strings (and objects in general) with equals, and not ==, but I am wondering whether it matters for the empty string.


Would infinitesimal and infinite just be antonyms of each other?

What is the opposite of "infinitesimal"?  Infinitesimal means a value smaller than the minimum possible measurement. For example, if we have a ruler with 1 centimeter intervals, then any length measured shorter than 1 cm is infinitesimal for that measuring instrument - smaller than the smallest possible measurement, but still greater than zero.  The opposite of infinitesimal means a value larger than the maximum possible measurement. Analogously, if we have a 100 centimeter ruler, then any length measured longer than 100 cm is that opposite term.  "Infinite" is not the opposite of infinitesimal, although that term is commonly (mis)used. Infinity is an abstract concept for something that never ends, not merely a value above measuring capability. For example, the question "how long is this road?" may have the answer "the opposite of infinitesimal" if we lack the capacity to travel along a straight road in its entirety and measure its length. On the other hand, if the road is short enough to see in its entirety but loops in on itself, we could say that its length is "infinite".  A term I came up with for this is "supermaximum"; above the maximum possible measured value. I would like to know if an official term exists.


In my Total Commander icon properties, I see Run as administrator in two places: the Compatibility tab settings, and the Shortcut tab (Advanced button).      Question  Are they both the same?  If not, what's the difference?

There are two checkboxes for Run As Administrator in the Properties dialog for a shortcut in Windows 7. One is under the Shortcut tab in the Advanced Properties dialog, and the other is under the Compatibility tab.  I've seen this under Windows 7 and Windows Server 2008. It might be in Vista and other versions, but I'm not sure.  What is the difference between these two settings?


Which is correct and are there any differences in meaning or nuance?  I have the data on my iPad  I have the data in my iPad   I searched data on my iPad and data in my iPad on google, and got many results on both sentences.

Do you say IN one of the computers or ON one of the computers? Which is right?


I defined my own counter which resets every time I call the environment ``environment1''. It works as expected.  \newcounter{ado}[environment1]   I wanted it to be reseted as well when I call the environment ``environment2''. Is there a simple way like the following?  \newcounter{ado}[environment1,environment2]   I am using  \setcounter{ado}{0}   prior to evironment2 environments but i was looking for anything more appropriate.

To get the output Toc or pdf bookmark below:   Part I     Chapter I     Chapter II Part II     Chapter I     Chapter II   I need to reset the chapter counter. I google and get one method.   \makeatletter \@addtoreset{chapter}{part} \makeatother   Yes, It can output like this. But hyperref package can not link to right target for chapters after chapter I. That is said page ref link broken.  I like to define all style in style file. the mini-document:   \documentclass[]{book} \usepackage[]{hyperref} \usepackage{mini} % my own style file  \begin{document} \tableofcontents \part{Test} \chapter{One} \chapter{Two} \part{Test} \chapter{Three} \chapter{Four} \end{document}    and the mini style file:   \renewcommand\part{%   \if@openright     \cleardoublepage   \else     \clearpage   \fi \setcounter{chapter}{0}} % I reset manually here.


By the dupe, the table implies $\,(14441,3565) = (3565,189) = \ldots = (28,21) = (21,7) = (7,0) = 7\ \ $ I understand that Euclid's algorithm on GCD is based on doing division via subtraction $x = qy + r$. I also understand that the process is keep expressing the quotient in terms of the remainder. Example to find GCD of $14441$, $3563$:     x    = q * y +  r     14441 4 3565 189   3565 18 189 161   189 1 161 28   161 5 28 21   28 1 21 7   21 3 7 0     So the GCD is $7$. So basically we try to divide the $2$ original numbers and then try to see if the remainder can express evenly $y$ and keep doing that recursively i.e. try to find the smallest number that divides the remainder. But I am not sure I understand the intuition behind the idea. Why would that process lead to the smallest number that divides the original $x$? I also read that a core idea is that $gcd(x,y) = gcd(y,r)$ but I didn't really get that part too. Could someone please help?

Given: $a = qb + r$. Then it holds that $\gcd(a,b)=\gcd(b,r)$. That doesn't sound logical to me. Why is this so?    Addendum by LePressentiment on 11/29/2013: (in the interest of  and averting a duplicate)  What's the intuition behind this result? I only recognise the proof and examples solely due to algebraic properties and formal definitions; I'd like to apprehend the result naturally.


I'm trying to find a term that refers to both a position and a timestamp associated with that position. "Position in time" is a common phrase. Are there more technical terms?  A position and timestamp would be expressed like this: a car was at 40.7484° N, 73.9857° W at Apr 23 15:08:16 UTC 2018  I found this question which has a lot of terminology for referring to these things individually:

Where such a term would reference the location/time of an object, almost like it was of a property of the object. That is to say, if a duck is red, blue, yellow etc, we describe it has having a certain colour. If it's a nanometre, or 10km big, then it's property of size.  Now I know that where/when an object exists an object isn't a property of an object, but it is something unique to that object, so I think it would be useful to have a shorthand for 'geographical location', and 'time of existence'.  There are terms describing both time and location, such an event, or rendezvous (which I think is used to describe the when and where of a meeting between two humans) but I wan't a term that just describes one of each.


Prove that the sequence $\{u_n\}$ is defined by $0\lt u_1\lt u_2 \;\text {and} \;u_{n+2}=\sqrt {u_{n+1}u_n}\; \text{for}\; n\ge 1$, converges to $\sqrt[3]{u_1{u_2}^2}$.   I did this using subsequences, I posted below. This kind of problems are usually done by monotonicity and boundedness. So, I suspect if their is a solution to this problem using this method.  I answered this in this method .

I managed to show that the limit exists, but I don't know how to compute it.  EDIT:  There are initial terms: $a_1=1$ and $a_2=2$.


I input a file inp.txt using its path relative to the directory containing the main.tex file and where I will run pdflatex:  \documentclass{article} \begin{document}     \input{../inputs/inp.txt} \end{document}   Is there a way to specify the absolute path of inp.txt, e.g. ~/inputs/inp.txt?  Since I am looking for a general solution to include \includegraphics, \input and \include files I try to use TEXINPUTS and modify my script:  \documentclass{article} \begin{document}     \input{inp.txt} \end{document}   When I run  TEXINPUTS=~/inputs pdflatex main.tex   it turns out I have changed my working directory producing the error message:  ! I can't find file `filepath.tex'.   Adding multiple paths TEXINPUTS=~/inputs:. produces other problems.  Is there a simple and concise solution?

Sometimes it is convenient to use an absolute path to include a preamble. To do so, I use the following "hack":  \documentclass[a4paper, 12pt]{article} \newcommand{\folder}{/path/to/folder} \input{\folder/preamble}  \begin{document} \end{document}   Now my question is, whether there is a more elegant way to do this, especially a way which is compatible with one of the flatten scripts from  ?


I am having some trouble solving this equation for $x$: $$a^x + b^x = c.$$ I thought I should use logs but am unable to.

Well the question is to solve for $x$ in $$a^x+b^x=c \tag{a,b,c are constants}$$   Well as of me, I tried to put $\ln{}$ on both sides which does not seem to help. Apart from this I don't seem to have any other way to solve it.   I turned to WolframAlpha and the solution which was given was : $$x=\dfrac{-i(2\pi n +\pi)}{\ln{a}-\ln{b}} , {n \in \mathbb{Z}}$$  And if $n=0$ $$x=\dfrac{-i\pi}{\ln{a}-\ln{b}}$$  The only thing I am able to recognize is $e^{i\pi}=1$ ... i guess is used.  Link :   So I see that $x$ is independent of the constant $c$.  So how to solve it? Please help...Thanks!    EDIT - It seems that WolframAlpha is taking $c=0$ as suggested by Donkey_2009. And when i write "Solve for x in a^x + b^x = k" it is not returning anything. So are you guys aware of a method to solve this? Also are you guys aware of any other website/software like WA?    P.S. - Also I see that IF we know the values of $a,b,c$ resulting in something like $2^x+3^x=100$ , then Newton's method is the only method I am aware of that can solve it...  Any other suggestions?


I had installed 64 bit Ubuntu 13.04 on my desktop. For first two login It accept my password but from today system can not accept my password. I had not changed the password. Please suggest solution to recover password.

I'm working on a Ubuntu system, and my client has completely forgotten his administrative password. He doesn't even remember entering one; however it is there.  I've tried the suggestions on the website, and I have been unsuccessful in deleting the password so that I can download applets required for running some files. Is there a solution?


I realise SE is about questions and aswers which are judged on their own merits, regardless of the person who asks or answers. People's contributions to the community are represented by more or less objective metrics like reputation or tag scores.  However, once in a while I wish I could recognize users who were especially helpful, or just nice or cool, beyond the simple upvote. Maybe if I had the chance to help them, answering their questions would've been my priority. Or perhaps I'd consider editing their answer to correct eventual mistakes, when I wouldn't do the same to help average Joe. Or I just want to "bookmark" them for future referece, because I like how their personal statement is phrased.  The simplest way I can see to achieve all this is to add the same kind of star to user profiles as we have for questions. This wouldn't affect such users in any way (though it may be a good idea to display how many people starred them in their profile), and I would see a star on their card and have a list of them in my profile for quick access.

Possible Duplicate:          I want to Favorite Users.  There are several users whose questions I always enjoy reading.  I would like to be able to Favorite them so I don't have to remember their usernames.


There are similar questions already posted but they are about upgrading to relatively newer version of xubuntu but not a huge jump as in my case. I have 14.04 which is quite an old release can this be upgraded to 20.04 without reinstall ?  Thanks

I am currently using Ubuntu 10.04. I know there is a 10.10 release, but can I upgrade directly to 11.04? Could you walk me through the steps please?


It's been said by some people: If it's worth answering, it's worth upvoting  What about making an answer automatically upvote the question, unless they explicitly downvote it?  I suggest this because I have seen many cases where a reasonable question has literally five different answers, and nobody has upvoted it! This is not because it is a bad question, it's just that noone bothered to upvote it!  It seems that in the great majority of cases people are not upvoting questions out of apathy. It may be reasonable to somehow automatically upvote a question when it gets answered (except by the OP, of course). What do you think? Can it work?

A good question will receive many answers, and much more views than normal.    This level of activity is not reflected in the upvoting of said question. I recently encountered several such questions, which until I pointed this in the comments () stayed in the lower 0-2 upvotes.    My two suggestions:   Automatically upvote any question you answer, with the ability to cancel this up-vote. This makes sense to me, as I answer only questions I like/are good (and I suppose others too). Display popup message similar to:       Have you considered upvoting this question?    Addressing comments given so far: Answers do not mean a question is good, but it does imply you have an opinion on it. So why not prompt any one who answers to express their opinion by voting? (Similar to what happens when you upvote an answer to your own question).


I'm replacing pads on my TRP Hy-Rd brakes. These are cable actuated hydraulics. Using tire levers, wrenches, etc. I have not been able to push the two pistons far enough apart to fit the rotor between the pads. I can move one piston, but the other follows, so there's no increase in the gap. I've tried pushing the pistons apart both with and without the old pads in place. Not having any luck. Any suggestions?

Really struggling with these brakes now. Just installed new pads, but pistons won't separate far enough to put the wheels back in. Tried pushing the piston in using a  plastic tyre remover, but no joy. It seems like one pad (hub side in both cases, front and back) is a lot further out that the other, which suggests sticky pads.  I'm also a bit confused as the pistons move (both pistons on both brakes) as soon as the actuator arm starts moving. I thought they were supposed to have a delay as a valve closed, so I'm wondering if they're actually properly set up at all. I can't see where the bleed valve is though, and if it's opening.  Any advice gratefully received!  Edit; I think there's three problems I'm working on here; i.) The pads are asymmetric; the outside pads are barely showing, the inside ones are protruding by about 2-3mm. ii.) Even with the cable detached and the arms locked out I can't push the protruding pad in. It moves slightly under extreme force, but moves back after the force is removed. iii.) The pads move as soon as the brake lever moves, which I don't think is right.  I'm going to try and clean the edges of the pistons I can get to, as following this you tube video                                and see if that helps at all, will report back.


If every thing in the universe suddenly doubled in size, and the physical constants changed accordingly, would we notice any effects?  if not, how can we possibly say if its not happening right now. what if everything's growing in size and the constants with it and we dont even know?

My question has a silly formulation, but I want to know if there is some sensible physical question buried in it:   Suppose an exact copy of our Universe is made, but where spatial distances and sizes are twice as large relative to ours. Would this universe evolve and function just as ours?   Since mass is proportional to volume which is distance cubed, but strength of a rope is only distance squared, I think not everything would scale proportionally.   Does this mean that a universe with our physical laws that evolves like ours can only have one particular size? Or would the physical laws scale proportionally so that it evolves in the same way? If it has a particular size, what is it relative to? Another variation: suppose another exact copy of our Universe is made, but where everything happened twice as fast relative to ours. Would it evolve in the same way as ours?


I was doing a Quantum Mechanics problem and came across the quantity $(-1)^{(-{1\over2})}$ within an infinite square well wavefuntion of $\Psi(x,t)=\Psi_1+e^{i\phi}\Psi_2$  and asked to analyze its mathematical behavior when $\phi=0,\pi,\pi/2$, and $\pi/2$ in my $\Psi_2$ presented the problem. I can't find any resources in my textbook or online about this quantity, except for , which didn't totally address my concern. How should complex numbers be treated in such a situation? It seems almost dependent on an order of operation, but there are two possible results: $i$ and $-i$. $$(-1)^{(-{1\over2})} = {(-1)^{{(-1)^{({1\over2})}}}} = \left({1\over-1}\right)^{({1\over2})} = \left({1\cdot(-1)\over(-1)\cdot(-1)}\right)^{({1\over2})} = (-1)^{({1\over2})} = i$$ or omission of the num & denom multiplication of $(-1)$ could result in the same output as below: $$(-1)^{(-{1\over2})} = {(-1)^{{({1\over2})^{(-1)}}}} = (i)^{(-1)} = \left({1\over i}\right) = \left({1\cdot i\over i\cdot i}\right) = \left({i \over -1}\right) = \left({i\cdot(-1)\over(-1)\cdot(-1)}\right) = -i$$ As the other post mentioned, online calculators favor the second result, but I couldn't glean whether there was a reason for that bias. Between these two (or something else), is there a more correct or conventional result, especially in Quantum Mechanics? I know that square roots yield both positive and negative results, but I beleive that only applies to real numbers, and I haven't yet learned enough complex analysis to know how they're treated in complex spaces. Any help would be appreciated!

$-1=(-1)^1=(-1)^\frac{2}{2}=((-1)^2)^\frac{1}{2}=\sqrt{(-1)^2}=\sqrt{1}=1$  This proof bugs me for the following reasons:   Mathematicians have defined the symbol $\sqrt{}$ (Named the principal square root) to mean 'take only the positive square root of the number under the radical' This makes it so that the $y = \sqrt{x}$ is a function and therefore for every x-value (input) there is only 1 y-value (output). Therefore $\sqrt{x^2}=|x|$ due to the above definition. But then this means $\sqrt{(-1)^2} = |-1| = 1!!!!$   I really don't understand what's wrong with the above proof, the only way this could make sense is to define $\sqrt{a} = \pm k$ where the symbol know gives rise to two solutions to the equation, but then y = $\sqrt{x}$ is not a function and is simply a relation.   If we have $\sqrt{a}=\pm k$ then $\sqrt{(-1)^2}$ can be equal to -1 as well and then $-1=(-1)^1=(-1)^\frac{2}{2}=((-1)^2)^\frac{1}{2}=\sqrt{(-1)^2} = -1 = -1$ and everything works out fine.  Side Note: Why do we even want y = $\sqrt{x}$ to be a function anyway? What's the harm in defining $\sqrt{x} = \pm k$ where y = $\sqrt{x}$ is not a function?     Proof for $\sqrt{x^2}=|x|$  Let k = $\sqrt{x^2}$ where k is a constant.  $k^2=(\sqrt{x^2})^2=(((x^2))^\frac{1}{2})^2$  $k^2=x^2$  $k^2-x^2=0$  $(k+x)(k-x)=0$  $k = x$ or $k=-x$  But $\sqrt{a}>0$ for $a>0$ by definition of the principal square root.  $\therefore k \neq-x$  In order to make this identity work properly, an absolute value sign is required.  $\therefore \sqrt{x^2}=|x|$    Btw, my question is not the same as why $\sqrt{-1\times-1}\neq(\sqrt{-1})^2$ as I am not using the property $\sqrt{a}\sqrt{b}=\sqrt{ab}$ here and I am not bringing up the concept of imaginary numbers.


I'd like to transcode a video to have faster playback speed, for use on mobile devices / chromecast. VLC has this capability, but it seems to only work during playback. For example, if I use the following command line,  vlc -I dummy -vvv "${input}" \     --rate=1.0 \     --audio-time-stretch \     --sout-x264-preset faster \     --sout-x264-crf=31 \     --sout \     "#transcode{vcodec=h264,acodec=mp3,ab=128}:file{dst=$output}" \     vlc://quit   Adjusting the --rate parameter seems not to work with transcoding--the audio seems to be not present. It does work with basic playback.  Has anyone gotten this to work? (I'm doing it for Coursera lectures FWIW). Thanks in advance.

I have an .mp4 file to turn into a timelapse movie.  How can I encode every n frames from the source movie into a new movie file, preferably using ffmpeg?  Solutions that extract a bunch of stills from the original and then re-encode are not OK, it will use too march hard disk space (but solutions that just use temporary images one by one and pipe them in are OK)  I found the following video filter:  ffmpeg -i in.mp4 -vf select='not(mod(n\,25))' out.mp4  But it seems to need tweaking, my output video is now still the same length but with a very slow framerate.


What's to stop the Weasleys from simply creating money? Can't they create gold, silver, or bronze? Why not make muggle money and exchange it at Gringotts? Old clothes? Or just use a doubling charm when purchasing an item for infinite "new" clothes?

Why, oh why, don't the Weasleys "conjure" up some diamonds/gold/etc, sell 'em to Muggles, and get rich? They could buy a mansion (like the Malfoys), and live there happily ever after.  I know there's  that prohibits one from conjuring food (which doesn't make much sense to me, either). Even if it applied to gold, what about all the other elements/compounds/materials? Could the law really be 'don't let a wizard conjure something if it'll make them richer'? That's totally nonsensical.  Why does Wizard society still have poor people, especially if they're talented?


I have several tar files (~270) which untar into the following separate directory structure:  00001.tar -> /00001/001/file1.ima  00002.tar -> /00002/001/file2.ima  . . .  00270.tar -> /00270/001/file270.ima  I wondered if there is a specifier in the untar command that would allow me to not only untar the files, but also move the files (file1.ima, file2.ima, . . . file217.ima) to a common directory.  Does anyone know how to do this? Sorry if this is a simple thing to do; I am pretty inexperienced in this (obviously).  Thanks hugely in advance for any help on this!

I have a directory :  ../Music with a lot of music files in a lot of subdirectories.  How would i move all the files in the subdirectories to another directory ? Thus, i only want to move the files, i don't want to keep the subdirectory structure.


I am to convert an SVG image to TikZ code. I have never done that before thus I have a few questions. First of all do I need Inkscape or any other program like this? Maybe there is a method using just Python? Have you ever done that before? Are there any typical errors or problems?

I was wondering if anyone had managed exporting .svg files to TikZ code. I do not mean include an .svg file into a latex document, but rather to obtain the code of an image so you can then edit it with TikZ.   I know that this has been done here:  using inkscape and the svg converter svg2tikz () but I cannot reproduce it after installing inkscape.   When I run inkscape, I get the following message on the console (I run it from the console):     (inkscape:8700): Gtk-CRITICAL **: gtk_misc_set_alignment: assertion `GTK_IS_MISC (misc)' failed   I can still import an image and export to TikZ path but I get the following error message in a pop-up window:     Inkscape encountered an internal error and will close now.   Automatic backups of unsaved documents were done to the following locations:   /home/squeeze/New document 1.2012_06_19_18_10_24.0.svg   and the exported .tex file shows the following code which does not reproduce the image and compiles to a blank page:  \documentclass{article} \usepackage[utf8]{inputenc} \usepackage{tikz}  \begin{document}  \begin{tikzpicture}[y=0.80pt,x=0.80pt,yscale=-1, inner sep=0pt, outer sep=0pt]   \begin{scope}[cm={{2.4087301,0.0,0.0,3.1036527,(-508.27381,-1163.9469)}}]     \begin{scope}[cm={{1.25,0.0,0.0,-1.25,(213.2835,636.20725)}}]       \begin{scope}[scale=0.100]         \begin{scope}[cm={{2304.0,0.0,0.0,1195.2,(141.732,141.732)}}]         \end{scope}       \end{scope}     \end{scope}   \end{scope}  \end{tikzpicture} \end{document}   Has anyone done it?  I run Debian Squeeze; Inkscape is 0.47 and the forum on the inkscape-svg converter is not really active so I thought someone may have done it here.  I do not wish to specifically use .svg; I use GIMP usually, so if there is such a way to do it in GIMP, I am happy to do it (even better).  Here is an example of an .svg image that fails the above procedure:


I need to generate either backups or data dumps for about 30 tables.  I want to generate a file of some sort that contains the data for these tables and transfer them to a different system.  Each table has 3.8-4.5 million rows.  also a large number of these rows have columns with text that has newline characters which need to be handled correctly.  I'm using Sql Server 2012 and have SQL Server Management Studio.  Due to security and other particular reasons I cannot just use SQL Server Managment Studio's Import/Export Wizard for simply exporting tables from one database to another.  I have a requirement to get a dump of the data to transfer to a remote system.  I have tried SQL Server Management Studio's Generate Scripts capability, which does appear to handle the newline characters, however There is another issue.  In some of the fields the text is similar to "something blah \".  that slash causes a problem with the script that gets generated, because the Generate Scripts process wraps that text in ''  and with \' it basically escapes the single quote which corrupts the remaining data.  I have also tried to generate flat files via SQL Server Management Studio's Import/Export wizard and this doesn't appear to handle the newline characters correctly and again corrupting the remaining data.  Any help would be greatly appreciated.  and I can clarify any information that is missing.

Is there a tool for quickly backup and restore a table's data, preferably to a csv file?  It would be best if I could do it using batch. Run a .cmd file and data is backed up into a file with datetime name. And anytime needed I can just run another .cmd file to restore a file into the table.


The issue is that I'm trying to select  elements with $("a") and its affect only few of the  tags in the document, my code  $(document).ready(function() {     $.ajax({         type: 'GET',         url: 'http://localhost/queryProjects',         success: function(data) {             var el = $('

');             el.html(data);             var ProjectsObject = $("b:contains('projectName')", el).parent().next();             var ProjectsArray = $.makeArray(ProjectsObject);             var DescriptionsObject = $("b:contains('description')", el).parent().next();             var DescriptionsArray = $.makeArray(DescriptionsObject);             for (var i = 0; i < ProjectsArray.length; i++) {                 $("tbody:last-child").append('
' + (i + 1) + '	' + ProjectsArray[i].textContent + '	' + '' + DescriptionsArray[i].textContent + '	Run
');             }         }     });     $("a#link").click(function() {         $("table").hide();     }); });   I have tried with an ID and without, like $("a") and $("a#link").  the AJAX is irrelevant but just so you see how I inject my info to the document.  Thanks!

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


I am trying to install pocketsphinx and after installation I should run these commands:  export LD_LIBRARY_PATH=/usr/local/lib export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig   But I am interested to know where does this command add the paths? If I want to do it manually, how can I do that?

My variables are   LD_LIBRARY_PATH=/usr/lib/oracle/11.2/client64/lib ORACLE_HOME=/usr/lib/oracle/11.2/client64   How to save these variables permanently ?


Title says it all, Ive got many an adaptor lying around, do I need another 6v .8a at 240v?  I should note ive had it plugged into the mains with a standard international adaptor for over three years now no problem. looking to lose the adaptor.

Power supplies are available in a wide range of voltage and current ratings.  If I have a device that has specific voltage and current ratings, how do those relate to the power ratings I need to specify?  What if I don't know the device's specs, but am replacing a previous power supply with particular ratings?  Is it OK to go lower voltage, or should it always be higher?  What about current?  I don't want a 10 A supply to damage my 1 A device.


Kindly follow the below HTML code. I want to get the text "DefaultBP" in between the  tag. If I using this XPath "//div[@class='workspace']//h1", all the texts including  tag such as "Export", "Import", "Tariff List" & "Add Prefix" are displayed. I want only the text "DefaultBP". Hope to hear from you soon.
      <input  type="hidden"  name="addressRuleId"  id="addressRuleId" value="1"/>

DefaultBP                     Export                     <input type="hidden" id="status" name="status" value="null">                     <input type="hidden" id="bpCode" name="bpCode" value="defaultbp">                     <input type="hidden" id="bpName" name="bpName" value="DefaultBP">                     <input type="hidden" id="addressRuleId" name="addressRuleId" value="1">                     Import                                                               Add Prefix                     Tariff List

Hello I am trying to find Load # detail from . Also You can  too.  I have tried with xpath: //div[@class='equipment_item']//text()[preceding-sibling::strong[text()='Load #:']][1]    But getting the below error:  org.openqa.selenium.InvalidSelectorException: The given selector //div[@class=' equipment_item']//text()[preceding-sibling::strong[text()='Load #:']][1] is either invalid or does not result in a WebElement. The following error occurred: InvalidSelectorError: The result of the xpath expression "//div[@class=' equipment_item']//text()[preceding-sibling::strong[text()='Load #:']][1]" is: [object Text]. It should be an element. Command duration or timeout: 31 milliseconds


Transforming from logit to probabilities in logistic regression models facilitate the interpretation when terms are additive. But, what about interactions?   How can I interpret probabilities when terms include interactions between continuous predictors, just as the same way as interpreting logit relations?

I have data from a survey experiment in which respondents were randomly assigned to one of four groups:  > summary(df$Group)        Control     Treatment1     Treatment2     Treatment3              59             63             62             66    While the three treatment groups do vary slightly in the stimulus applied, the main distinction that I care about is between the control and treatment groups. So I defined a dummy variable Control:  > summary(df$Control)      TRUE FALSE         59   191    In the survey, respondents were asked (among other things) to choose which of two things they preferred:   > summary(df$Prefer)       A   B  NA's      152  93   5    Then, after receiving some stimulus as determined by their treatment group (and none if they were in the control group), respondents were asked to choose between the same two things:  > summary(df$Choice)   A    B  149  101    I want to know if the being in one of the three treatment groups had an effect on the choice that respondents made in this last question. My hypothesis is that respondents who received a treatment are more likely to choose A than B.       Given that I am working with categorical data, I have decided to use a logit regression (feel free to chime in if you think that's incorrect). Since respondents were randomly assigned, I am under the impression that I shouldn't necessarily need to control for other variables (e.g. demographics), so I have left those out for this question. My first model was simply the following:  > x0 <- glm(Product ~ Control + Prefer, data=df, family=binomial(link="logit")) > summary(x0)  Call: glm(formula = Choice ~ Control + Prefer, family = binomial(link = "logit"),      data = df)  Deviance Residuals:      Min       1Q   Median       3Q      Max   -1.8366  -0.5850  -0.5850   0.7663   1.9235    Coefficients:                     Estimate Std. Error z value Pr(>|z|)     (Intercept)           1.4819     0.3829   3.871 0.000109 *** ControlFALSE         -0.4068     0.3760  -1.082 0.279224     PreferA              -2.7538     0.3269  -8.424  < 2e-16 *** --- Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1  (Dispersion parameter for binomial family taken to be 1)      Null deviance: 328.95  on 244  degrees of freedom Residual deviance: 239.69  on 242  degrees of freedom   (5 observations deleted due to missingness) AIC: 245.69  Number of Fisher Scoring iterations: 4   I am under the impression that the intercept being statistically significant is not something that holds interpretable meaning. I thought perhaps that I should include an interaction term as follows:  > x1 <- glm(Choice ~ Control + Prefer + Control:Prefer, data=df, family=binomial(link="logit")) > summary(x1)  Call: glm(formula = Product ~ Control + Prefer + Control:Prefer, family = binomial(link = "logit"),      data = df)  Deviance Residuals:      Min       1Q   Median       3Q      Max   -2.5211  -0.6424  -0.5003   0.8519   2.0688    Coefficients:                                  Estimate Std. Error z value Pr(>|z|)     (Intercept)                         3.135      1.021   3.070  0.00214 **  ControlFALSE                       -2.309      1.054  -2.190  0.02853 *   PreferA                            -5.150      1.152  -4.472 7.75e-06 *** ControlFALSE:PreferA                2.850      1.204   2.367  0.01795 *   --- Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1  (Dispersion parameter for binomial family taken to be 1)      Null deviance: 328.95  on 244  degrees of freedom Residual deviance: 231.27  on 241  degrees of freedom   (5 observations deleted due to missingness) AIC: 239.27  Number of Fisher Scoring iterations: 5   Now the respondents status as in a treatment group has the expected effect. Was this a valid set of steps? How can I interpret the interaction term ControlFALSE:PreferA? Are the other coefficients still the log odds?


I'm trying install a lamp to my apartment but it didn't light up as I expected. I recently moved in and this is the first time I'm trying to install a lamp here. The spot where I'm trying to install the lamp is just a hole in the ceiling with three wires hanging out: Two brown (live?) and one blue (neutral?). Some Googling revealed to me that the separate live wires can be used to control specific bulbs in a multi-bulb lamp. Nearby there is a switch on the wall with two buttons which I assume is for these wires. So apparently the idea is that current flows from each live wire through the bulbs to the common neutral wire when to buttons are toggled on. One live wire and the neutral were connected in parallel to a connection strip, while the other live wire was connected alone to its own connection strip.  My lamp has a spring-powered connection strip with L and N labeled holes so I simply took one of the brown wires to L and the blue wire to N.  I removed the connection strips and tried to measure the voltage to see if the problem was somewhere else in the circuit, and I noticed that each of the live wires measures around 50-54 volts with respect to the neutral, even though the AC line voltage in my country is 240 volts. Even stranger, I measured this voltage regardless of the positions of the switch buttons! Only when I removed the fuse I got 0 volts.  So I assume the reason why the lamp didn't light up was that the voltage was way too low. Could somebody point what is it that I'm doing wrong, or is there something wrong with the wiring on my apartment?

I just replaced a broken light fixture in my closet. (The switch in the light fixture broke when I pulled too hard on the chain.)   When replacing the light fixture I noticed that there is only 30 V AC between the white and black wires. The ground wire is cut back and is not being used. By the way, the wiring in my house is all aluminum.   I know the new light fixture works. I checked it out with my multimeter, and I tried it in a different closet. But the light bulb won't turn on because there is only 30 V. (Even if I disconnect the light fixture completely there is still only 30 V.   It seems to me that it must be a problem with the wiring.  My attic does provide some (difficult) access to the wiring, but I am not sure where to start looking for the problem or what to look for. Can anyone offer some suggestions?


I read through several questions raised before, but couldn't find a direct solution. I'm using overleaf online latex editor to compile my .tex file. I handle a separate .bib file for references. I need my document to be referenced in Harvard (aka "authoryear") style, with et. al. in italics. Here's the partial code of my main document: \documentclass{article} \usepackage{natbib}  \begin{document}  I want to cite this \citep{auth} here.  \bibliographystyle{agsm} % 'agsm' is part of 'harvard' package \bibliography{ref}  \end{document}  In the ref.bib` file I has the following: @article{auth,   title = {xxx},   year = {2000},   author = {aaa, bbb, ccc and ddd} }  What I want here is (aaa et al. 2000) instead of (aaa et al. 2000). Please help. Thanks in advance.

I am using natbib and agsm for harvard-style referencing. My related code is  \usepackage{natbib} \bibliographystyle{agsm}   Then I am using \citep{} for citations. My problem is that in text I am getting     (Author et al. 2012)   but and I want     (Author et al. 2012)   Does anyone know how to change this and get 'et al' in italics in the text?  I am using TexPad and BibDesk and I have not been able to find the .bst files in Terminal.  I know that it is often correct to have the 'et al.' unitalicised but my university regulations requires italics.


I have a nice icon and I want to use it on all of the forms in my application. How can I do this?

Is there any way to set the same icon to all my forms without having to change one by one? Something like when you setup GlobalAssemblyInfo for all your projects inside your solution.


Based on the below link as an example:  ...if a link tag contains the class "add-selected", I want jquery to add an href called "#scrollTo" to all corresponding 's.       Add Selected    Final result after page loads should be:       Add Selected

How can you change the href for a hyperlink using jQuery?


I'm new with using Linux, so I don't know, how to install downloaded programms (downloaded with Firefox). Could anybody please give me a discription. Best would be in german, but english is ok too.

How can I install applications like Google Chrome on Ubuntu?  Are there any commands to install an application?    Index of answers:


10.9.5 here  Suddenly my Application Switcher won't cycle anymore on hold. It still can cycle between apps one by one, but if I hold command tab it will stop after reaching the right end of the row. Before that it used to keep cycling until I release command tab.  It's not so much that the loss of this minor feature is annoying, it is why it happened in the first place. As far as I know I didn't install any new app nor change anything. I found out that the same is true for any session not just mine. I also tried safe boot to no avail.  Thanks for any hint.

Is there anyway to have the Command+TAB app switcher continuously cycle instead of stop at the end when you hold down command and tab like it did pre Mavericks?


How do I plot a trail in ArcMap so that it runs from point A to point B? This is part of a larger model I am working on that takes various variables into account and creates a cost layer that I then can use to run a cost path analysis to determine the "cheapest" path between 2 points. Up until now, slope hasn't been too important. I am just now working with slope in the model, and I am trying to think of a method that would create a preference map of sorts to influence the trail to be plotted perpendicular to the slope. It is fine if the trail has a change in elevation, as that is pretty typical, but I want the slope to influence the trail and cause the generated trail to more closely conform to be perpendicular to the slope.

I'm a forester, and I do lots of work with LiDAR derived DEM's. I'm looking for a quick-and-easy tool to calculate the slope between two points. The application for this would be drawing a proposed road, where the slope of each road segment must be below a certain value. After quite a bit of searching, I'm unable to find a tool to accomplish this in ArcMap. Can anyone suggest an existing tool to accomplish this? I don't need the slope along the surface of a DEM; I simply need a FAST way to calculate the straight-line slope between two points. Currently, the only way I'm able to do this is as follows:  Load DEM into ArcMap. Create a new shapefile. Create a line feature with a single segment. Get the elevation values for the lines two vertices from the underlying DEM. Use math to calculate the slope of the straight line between the two vertices.  I'm looking for a workflow similar to the following:  Click on "slope" tool. Click on point A, then click on point B. Dialogue box displays the straight-line slope between point A and point B.  I've been looking for an existing solution to accomplish this, and have come up empty handed.


Let $\mathfrak{m}$ be a maximal ideal of $\mathbb{Z}[X,Y]$. Then does $\mathfrak{m}$ contain a prime number?  I think that for a prime ideal $\mathfrak{p} = (f_1, \dots, f_m)$ and a prime number $p$ which divides no coefficients of $f_i$. But I can't show it.

Suppose $k$ is a field that is finitely generated as a ${\mathbb Z}$-algebra.  (That is, $k$ is a quotient of ${\mathbb Z}[X_1,\dots,X_n]$ for some $n$). Does it follow that $k$ is finite?


Sometimes I lose a link to a deleted question and find it it my profile. It seems more helpful to have a complete list of deleted questions. But only recet deleted question links are available.

I would really like to see all of my questions and answers on the profile page, even if some of them were deleted, and I don't have enough rep to see them on the site. (Note that some questions are  after 30 days or 1 year, and the author might be oblivious about what happened.)   , the "deleted recent [questions/answers]" links in one's own user profile now list all respective posts that were deleted in the past 60 days, rather than just those that were originally posted in the last 60 days. , users with the "access to moderator tools" privilege (10k+ on designed sites, 2k+ on beta and non-designed sites) can use the search operator deleted:1 to see all their own deleted posts. , deleted questions and answers that were posted in the past 60 days, can be seen using the "deleted recent questions" and "deleted recent answers" links on the questions and answers tabs (at the bottom of the tab) in your user profile. For older posts: as of 2013-04-23 you can  if you already have a link to them, but they still aren't linked from the user profiles (not even just for you). Nor do you see inbox notifications for comments on them if you come back a few hours later. You have to have thought to bookmark your question, or you have to go digging for it in your browser history.


Here is the expression:     $$2(\sin^6x + \cos^6x) - 3(\sin^4 x + \cos^4 x) + 1$$   The exercise is to evaluate it.  In my text book the answer is $0$ I tried to factor the expression, but it got me nowhere.

I'm trying to prove a trigonometric identity but I can't. I've been trying a lot but I can't prove it. The identity says like this: $$3\sin^4x-2\sin^6x=1-3\cos^4x+2\cos^6x$$  The identity would be easy if $1-\cos^4x=\sin^4x$ and $1-\cos^6x=\sin^6x$ but we know that $\sin^4x+\cos^4x$ isn't equal with $1$ and $\sin^6x+\cos^6x$ isn't equal with $1$.   Can anybody help me?!  Thank you!


I want to build an Ender pearl dispenser that gives me a specific amount of pearls if i step on a pressure plate.   How do I do that?

Motivation: I have a grinder that spawns spiders which are then moved to a very small space. When they accumulate in big enough numbers, I pull a lever and let a piston crush them 11 times. Then I can kill them with one hit and harvest experience.     This becomes a problem once there are a lot of spiders - the game starts to lag and it is difficult (if not impossible) to have the precise number of hits.   Question: For some n, how do I create a circuit that generates n impulses before shutting down? Or in this case, how do I make a piston hit exactly 11 times?


How to list only files which begin with a period character? I want to know how this it possible with ls, grep and find.

I have a directory that contains thousands of files, some of them are hidden.  The command ls -a list all files, including hidden ones, but I need just to list hidden files.  What command should I use?


Hi I have a problem with a solution to my previous question about getting something to check if the server is started. So when I use Pgrep -f in my startup script to check if the MC server is running, it does the job, but after multiple restarts the terminal window starts showing pid numbers instead of the actual Minecraft commandline. This was not a problem before since I used to run it with GUI which I don't do anymore.  My startup script looks like this #!/bin/sh while true do     if ! pgrep -f server.jar     then         java -Xms6G -Xmx6G -XX:+UseG1GC -XX:+ParallelRefProcEnabled -XX:MaxGCPauseMillis=200 -          XX:+UnlockExperimentalVMOptions -XX:+DisableExplicitGC -XX:+AlwaysPreTouch -          XX:G1NewSizePercent=30 -XX:G1MaxNewSizePercent=40 -XX:G1HeapRegionSize=8M -          XX:G1ReservePercent=20 -XX:G1HeapWastePercent=5 -XX:G1MixedGCCountTarget=4 -          XX:InitiatingHeapOccupancyPercent=15 -XX:G1MixedGCLiveThresholdPercent=90 -          XX:G1RSetUpdatingPauseTimePercent=5 -XX:SurvivorRatio=32 -XX:+PerfDisableSharedMem -          XX:MaxTenuringThreshold=1 -Dusing.aikars.flags=https://mcflags.emc.gs -Daikars.new.flags=true          -jar server.jar --nogui     fi     sleep 5 done

I have a Bash script that runs a program with parameters.  That program outputs some status (doing this, doing that...). There isn't any option for this program to be quiet. How can I prevent the script from displaying anything?  I am looking for something like Windows' .


I saw  and did:  In the app software & updates, checked:  canonical-supported free and open-source software (main) community-maintained free and open-source software(universe).  Copping the code block in that thread (I could not show here because I do not have reputation) and pasted to sources.list, after replacing precise to focal. Saved, then, sudo apt-get update  The result was the number ‘58’ became ‘55’- only.  Visited repogen dot simplylinux dot ch  My version Focal was not on the list.   hp-check and got: error: 'libcups2' package is missing/incompatible  error: 'libdbus-1-dev' package is missing/incompatible  error: 'libjpeg-dev' package is missing/incompatible  error: 'libcups2-dev' package is missing/incompatible  error: 'cups-bsd' package is missing/incompatible  error: 'cups-client' package is missing/incompatible  error: 'libcupsimage2-dev' package is missing/incompatible  error: 'build-essential' package is missing/incompatible  error: 'libusb-1.0.0-dev' package is missing/incompatible  error: 'libusb-0.1-4' package is missing/incompatible  error: 'libsane-dev' package is missing/incompatible  error: 'libsnmp-dev' package is missing/incompatible  error: 'snmp-mibs-downloader' package is missing/incompatible  error: 'openssl' package is missing/incompatible  error: 'python3-pyqt4' package is missing/incompatible  error: 'gtk2-engines-pixbuf' package is missing/incompatible  error: 'python3-dev' package is missing/incompatible  error: 'libtool' package is missing/incompatible  error: 'libtool-bin' package is missing/incompatible  error: 'build-essential' package is missing/incompatible

I have Ubuntu 12.04 LTS. I need the correct output because I edited it because it wasn't working but it has only made it worse.


I know that according to the NDA which you accept before taking the exam it is prohibited to discuss, reveal, share etc but the question is very hot - let's suppose I've faced a bunch of questions which are ...ambiguous or strange or do not have the correct answer IMO and I want to discuss it (in fact ask a question(s) and discuss possible answers using hivemind).     Posting each question as a separate thread on different board (e.g. SO\SU\ShP\DBA etc) is a bad idea (as for me) that's why this question has risen.    To not mess with the NDA and Microsoft rights, let's say I can "wrap an exam question in a "veiled form" of a SO-type question" for example.    Maybe the other (better?) way exists of course.    The main idea is that there is no "dedicated" site to discuss exam questions all around the Internet - and of course, I wouldn't say that dumps-selling sites are the perfect place to discuss the Q&A.    Anyway, I'll be very appreciated for pointing me in the right direction - I really hope that this idea has visited not only me and not only today:)    PS Do not offer the born-to-learn community, please.

I have an idea or subject that should have a Q&A, and want to propose a new site. How can I do this?  Related:


So I'm doing the tensorflow tutorial found here:    Basically, my input is a [28x28] matrix (image) that I flatten to a [1x784] vector.  The tutorial then says:     We scale these values to a range of 0 to 1 before feeding to the neural network model. For this, cast the datatype of the image components from an integer to a float, and divide by 255.   My question is why do we need to normalize in this case? My understanding is that when we have features that are on different scales, we need normalization if not the output of the model is distorted. But in this case all pixel ranges go from 0 to 255 (all features are the same scale)  I went ahead and ran it with normalization, and get an accuracy of over 85%, whereas no normalization, my accuracy falls to 10%.  Any ideas?

I'm quite new to neural networks and currently I'm trying to train a non convolutional neural network on the MNIST data set. I'm observing some behaviour I don't quite understand.   This is the code written with keras as the library:  # the data, split between train and test sets (x_train, y_train), (x_test, y_test) = fashion_mnist.load_data()  y_train = keras.utils.to_categorical(y_train, 10) y_test = keras.utils.to_categorical(y_test, 10) model = Sequential()  early_stopper = EarlyStopping(patience=3)  model.add(Flatten(input_shape=(28,28))) model.add(Dense(128, activation="relu")) model.add(Dense(128, activation="relu")) model.add(Dense(10, activation="softmax")) model.compile(loss="categorical_crossentropy", optimizer="adam", metrics=["accuracy"])  model.fit(x_train, y_train, epochs=20, validation_data=(x_test, y_test), callbacks=[early_stopper])   This gives me a validation_acc of around 20%. The funny thing is, when I change the activation functions to "sigmoid", the loss function to "mean_squared_error" and the optimizer to "sgd" my performance improves to around 85% after 50 epochs.   Having read  I wonder what's the reason for the bad performance of the network I presented in the code. ReLU, cross-entropy and a dynamic optimizer like Adam all seem to improve on the idea of a very vanilla neural network with stochastic gradient optimization, mean squared error as loss and sigmoid activation functions. Yet I get a really bad performance and if I increase the number of nodes in the hidden layers I often get a network that doesn't learn at all.   EDIT: I figured out it has something to do with me not normalizing the input to values between 0 and 1 ... but why is this the problem?


Hi and thanks for any help re the below  This is a fairly complex question so I will attempt to ask it in a fairly basic manor.   I have data on the abundance of 99 different species of estuarine macroinvertebrate species and the sediment mud content (0 - 100 %) in which each observation was obtained. I have a total of 1402 observations for each species (i.e. a massive dataset).   Here is a subset of the raw data for one species to give you an idea of the data I'm working with (if I had 10 reputation points i'd upload a plot of real raw data:  Abundance: 10,14,10,3,3,3,3,4,5,5,0,0,0,0,0,0,0,0,0,0,0,0,0,6,6,6,0,0,0,0,12,0,0,0,34,0,0 Mud %:     0.9,4,2,10,13,14,6,5,5,7,22,27,34,37,47,58,54,70,54,80,90,65,56,7,8,34,67,54,32,1,57,45,49,4,78,65,45,35   The primary aim of my research is to determine an "optimum mud % range" (e.g. 15 - 45 %) and "distribution mud % range" (e.g. 0 - 80 %) for each of the 99 invertebrate species.  As you can see the abundance data for the above species contains a significant number of zero values. Although this significantly skews any sort of model that I run on the data (i.e. GLM, GAM), even if I model the non-zero data only, the model for certain species does not fit the data at all well.  So, my question is: what would be the best, most robust way to determine an "optimum" and "distribution" mud range for a given species, given that responses vary significantly between species?

This is a fairly complex question so I will attempt to ask it in a fairly basic manner.   I have data on the abundance of 99 different species of estuarine macroinvertebrate species and the sediment mud content (0 - 100 %) in which each observation was obtained. I have a total of 1402 observations for each species (i.e. a massive dataset).   Here is a subset of the raw data for one species to give you an idea of the data I'm working with (if I had 10 reputation points I'd upload a plot of real raw data):  Abundance: 10,14,10,3,3,3,3,4,5,5,0,0,0,0,0,0,0,0,0,0,0,0,0,6,6,6,0,0,0,0,12,0,0,0,34,0,0 Mud %:     0.9,4,2,10,13,14,6,5,5,7,22,27,34,37,47,58,54,70,54,80,90,65,56,7,8,34,67,54,32,1,57,45,49,4,78,65,45,35   The primary aim of my research is to determine an "optimum mud % range" (e.g. 15 - 45 %) and "distribution mud % range" (e.g. 0 - 80 %) for each of the 99 invertebrate species.  As you can see the abundance data for the above species contains a significant number of zero values. Although this significantly skews any sort of model that I run on the data (i.e. GLM, GAM), even if I model the non-zero data only, the model for certain species does not fit the data at all well.  So, my question is: what would be the best, most robust way to determine an "optimum" and "distribution" mud range for each species, given that responses vary significantly between species?     Just to clarify - the above data is a hypothetical example to give you an idea of how messy the abundance (that is count) data can be for a given species.  Regarding the poisson regression approach: I'm considering conducting a two-step GLM or GAM approach for each species; Step (1) uses logistic regression to model the "probability of presence"  for a given species over the mud gradient - using presence/absence data. This obviously takes into account the zero counts; and Step (2) models the "maximum abundance" over the mud gradient - using presence only count data. This step gives me an idea of the species typical response to mud where they DO occur. What are your thoughts on this approach?  I have R code for both steps for one particular species. Heres the code:       ## BINARY  aa1<-glm(Bin~Mud,dist=binomial,data=Antho) xmin <- ceiling(min(Antho$Mud))     xmax <- floor(max(Antho$Mud)) Mudnew <- seq(from=xmin, to=xmax, by=0.1) pred.dat <- data.frame(Mudnew) names(pred.dat) <- "Mud" pred.aa1 <- data.frame(predict.glm(aa1, pred.dat, se.fit=TRUE, type="response")) pred.aa1.comb <- data.frame(pred.dat, pred.aa1) names(pred.aa1.comb) plot(fit ~ Mud, data=pred.aa1.comb, type="l", lwd=2, col=1, ylab="Probability of presence", xlab="Mud content (%)", ylim=c(0,1))   ## Maximum abundance   aa2<-glm(Maxabund~Mud,family=Gamma,data=antho)  xmin <- ceiling(min(antho$Mud))      xmax <- floor(max(antho$Mud))  Mudnew <- seq(from=xmin, to=xmax, by=0.1)  pred.dat <- data.frame(Mudnew)  names(pred.dat) <- "Mud"  pred.aa2 <- data.frame(predict.glm(aa2, pred.dat, se.fit=TRUE, type="response"))  pred.aa2.comb <- data.frame(pred.dat, pred.aa2)  names(pred.aa2.comb)  plot(fit ~ Mud, data=pred.aa2.comb, type="l", lwd=2, col=1, ylab="Maximum abundance per 0.0132 m2", xlab="Mud content (%)")  AIC(aa2)   My question is: for step (2); will the model code need to be altered (i.e. family=) depending on the shape of each species abundance data, if so, would I just need to inspect a scatter plot of the raw presence only abundance data to confirm the use of a certain function? and how would the code be written for a certain species exhibiting a certain response/functional form?


Let $f$ be a holomorphic function on unit disk $D$. (a). express the Jacobian of the map $f$ in terms of $f$ or $f'$ (b).Give a formula for the area of $f(D)$  in terms of the Taylor Coefficients of $f$. (c).If $f(x)=z+\dfrac{z^{2}}{2}$,find the area of $f(D)$.  My solotion: (a). According to Cauchy-Riemann equation,I compute the Jacobian of the map $f$ as $|f'(x)|^{2}$.             （b).From the elementary calculus,the area of $f(D)$ can be computed  according to coordinate transform.So $\iint_{f\left(D\right)}dw=\iint_{D}\left|f'\left(D\right)\right|^{2}dz$.But I don't know how to express it in terms of Taylor coefficients.              (c).Followed from the result in (b), Area$f(D)$=$\iint_{D}\left|1+re^{i\theta}\right|^{2}drd\theta=\dfrac{4}{3}$  Are my results valid and what about answer for the second question?

Let $f$ have power series $f(z) = \sum_{n=1}^\infty a_n z^n$ in $D$, then prove that   $\mathrm{area}\, f(D) = \sum_{n=1}^\infty n \,|a_n|^2$.  Note: We define $\mathrm{area}\, S = \iint_S \mathrm{d}x\,\mathrm{d}y$.  I presume the way to do this is to take the integral $$\iint_{f(D)} \mathrm{d}x\,\mathrm{d}y = \iint_D \mathbf{J}_f (x+iy) \,\mathrm{d}x\,\mathrm{d}y = \int_0^1 \int_0^{2\pi} r \mathbf{J}_f (r e^{i \theta}) \mathrm{d}\theta\,\mathrm{d}r,$$ and letting $\gamma_r : [0,2\pi]\to\Bbb{C}, \,\gamma_r (\theta) = r e^{i\theta},\, \gamma_r '(\theta) = i\gamma_r (\theta),$ then we get $$\mathrm{area}\,f(D) = \int_0^1 \int_{\gamma_r}\frac{\lvert f'(z)\rvert^2 \bar{z}}{ir}\mathrm{d}z\,\mathrm{d}r.$$ Unfortunately, this approach seems to be a dead end. I think I'm meant to use Cauchy's Formula somewhere, but I can't see where that might be useful in this kind of question.


Any classic Whovian will know that the Master is never dead, just renegotiating his contract with life.  I just want to know how the writers justified his return as the Mistress in season 8.  What in-universe reason is there behind the Master's return?

How is it that       The Master   Came to be in the Nethersphere?  The last time we saw him      He died and refused to regenerate.  The Doctor even cremated his body.   So, given what previously happened to him, how was he now able to      Regenerate as Missy and take over the Nethersphere?


Im trying to round a number to an epsilon, but sometimes it works, sometimes it doesn't. Any explanations to this, and how to make it work?. The following code is in java, but suspect it is something common among other languages.  float roundToEpsilon(float number, float epsilon){   float makeInt = number / epsilon;    int bigNumber = (int) (number / epsilon) ;    float ret = bigNumber * epsilon;   return ret; }  float ep = .01; println(roundToEpsilon(random(0,1),ep));      Results  0.76 0.42 0.51 0.58 0.35999998 0.53999996 0.35999998 0.03   I dont know why I am getting this 0.35999998??

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


Are there any converters that can take a Scientific Word code and make it pure LaTeX code?  Don't read what follows:  Below this line is some nonsense I had to write in order to be able to ask the question.

I am using this program "Scientific Workplace", which seems to have a proprietary-non-standard version of LaTeX, i.e., a version that cannot be readily interpreted by standard Latex readers; I uploaded a .tex workplace file to someone who has a LaTeX reader, and no matter how he tried to open it, all he got was a garbled mess.  Does anyone know how to go around this, i.e., does anyone now if there is a special way of saving a file in Sci Workplace, or some other trick so that a Sci. Workplace-version Latex file can be  read by standard LaTeX readers?


It is well accepted that nothing with mass can travel at the speed of light in vacuum, $c$. Now let's say that a light wave is traveling through a medium that slows the wave's speed significantly (less than $c$). Since we are able to accelerate objects to over 99% the speed of light (via LHC), could we potentially create a situation in which we could view a stationary light wave as Einstein first wondered during his childhood?

While the speed of light in vacuum is a universal constant ($c$), the speed at which light propagates in other materials/mediums may be less than $c$. This is obviously suggested by the fact that different materials (especially in the case of transparent ones) have a particular .  But surely, matter or even photons can be accelerated beyond this speed in a medium?  If so, what are the effects?


Background: my code takes the changes of a git merge request and compares the extentions with a rule file, which says which file was changed (for example implementation file because .py was changed). Now I want to do a mapping. If something in the implementation files are changed I want to save this information. I just did an boolean implementation_check = False. My change_log_array list has so many arrays like my rules. If the rule is not triggered the array will stay empty (for example a file with requirements) Question: Now I have some empty arrays in my list (in the beginning or in the middle of the list). How can I check if an array is empty? like if x is not None:

For example, if passed the following:  a = []   How do I check to see if a is empty?


I just noticed today that if I click on "add comment" my cursor doesn't automatically jump to the newly opened comment box - I have to make a second click before I start typing. I think this just started happening today.

Clicking on Add Comment used to focus on the comment area so one could start typing immediately instead of having to click in the textbox (unless I just imagined it)  Can we please reinstate that process (or create it if it never existed)?  I find myself clicking on Add Comment and typing for a couple seconds before realizing that the comment box was not focused and I was doing nothing...


I cannot install aptitude tool on ubuntu 16.4. Whenever I try installing it, an error comes up as follows:  E: Could not open lock file /var/lib/dpkg/lock - open (13: Permission denied) E: Unable to lock the administration directory (/var/lib/dpkg/), are you root?   What does this mean and how do I solve this??

I get this error whenever I try to install programs using the terminal:  home@ubuntu:~$ apt-get install myunity E: Could not open lock file /var/lib/dpkg/lock - open (13: Permission denied) E: Unable to lock the administration directory (/var/lib/dpkg/), are you root?   Also I'm unable to install updates using the terminal.


In this part requires to replace it:      $sql = "SELECT * FROM wallets WHERE id = '$user' LIMIT 1";   Requires to do this: use the mysql_real_escape_string() function for the $user parameter  How to implement it?  $sql = "SELECT * FROM wallets WHERE id = '$user' LIMIT 1";   Eliminate vulnerability!

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


I am travelling from Toulouse to Gare Montparnasse, then to Gare du Nord.  I have read  but how to go in the opposite direction?

On Friday I'm going to Angers from Brussels. The train from Brussels, which is a Thalys, arrives in Paris Nord.   55 minutes later, the train to Anger, which is a TGV, departs from Gare Montparnasse.  How can I travel the fastest way from Garde du Nord to Gare Montparnasse? Should I take the metro or a taxi? And if I take the metro, are the railways close to the metro or is it a long walk?


I'm not sure is this is the right SE to ask but I'll ask non the less.  I'm trying to define a family relationship. I think the person is my step step first cousin once removed.  My my Grand-Father is his Step-Great-Grand-Father. My Mother and his Step-Grand-Father are Step-Brother/Sister.  This is also by marriage, not by blood line so is there another term for that?  [] = Male  () = Female  [F] = My Step-Uncle  [H] = His Step-Father  [H] + (I) = Currently married  [J] + (I) = J, divorced or passed away     (A)-+-[B]-----+-(C)        |         | [D]-+-(E)       [F]-+-(G)     |               |   [ME]             [H]-+-(I)-+-[J]                              |                            [Him]

Here at the Genealogy and Family History Stack Exchange we see many questions about relationship mapping which is also known as:   relationship calculation kinship terminology etc   If you are just trying to understand how to calculate "cousins and removes" then  provides an excellent guide.  However, if you are seeking an English term for a more complicated relationship between two members of an extended family, rather than asking a question like:          site users are encouraged to first review the answers below.    Note: This Q&A arises from  and is set to  to help make it canonical.


Consider a point particle in $n$ dimensions. For a Lagrangian $\mathcal L(\mathbf{q, \dot q}, t)$, we have that $\mathbf q(t)$ is a feasible trajectory for times $t_0<t<t_f$ iff it extremizes the integral $$ \int_{t_0}^{t_f}\mathcal L(\mathbf q(t), \mathbf{\dot q}(t), t)\;dt. $$ This is equivalent to saying that E-L equation $$ \frac{\partial\mathcal L}{\partial\mathbf q} (\mathbf q(t), \mathbf{\dot q}(t), t) =  \left[ \frac{d}{dt'} \frac{\partial\mathcal L}{\partial\mathbf{\dot q}} (\mathbf q(t'), \mathbf{\dot q}(t'), t') \right]_{t'=t} $$ is satisfied. Now, suppose that I give a Hamiltonian $H(\mathbf{q, p}, t)$ for the particle. Then, for a feasible phase space path $(\mathbf q(t), \mathbf p(t))$, there are Hamilton's equations \begin{align*} \frac{\partial H}{\partial\mathbf q}(\mathbf q(t), \mathbf p(t), t) &= -\mathbf{\dot p}(t)\\ \frac{\partial H}{\partial\mathbf p}(\mathbf q(t), \mathbf p(t), t) &= \mathbf{\dot q}(t) \end{align*} which are satisfied. Now, I am aware that I can construct a Lagrangian (supplying$\frac{\partial H}{\partial\mathbf p}(\mathbf{q, p}, t)$ in Lagrangian's $\mathbf{\dot q}$) and this will give me a corresponding action integral, which will be extremized iff the the above Hamilton's equations are satisfied. Question: Is there something that can be extremized in Hamiltonian formalism that is equivalent to Hamilton's equations, which does not rely on defining Lagrangians?

The least-action principle is a statement in classical physics saying that all bodies in a system follow a trajectory that minimize the following functional (ignoring explicit time dependence for now): $$ S[L] = \int dt L(x(t), \dot{x}(t)) \qquad\rightarrow\qquad  \frac{d}{dt}\Big(\frac{\partial L}{\partial \dot{x}}\Big) - \frac{\partial L}{\partial x} = 0. $$ The Hamiltonian of the same system can be constructed using the Legendre transform: $$ H(p, x) = \dot{x}\cdot p - L(x, \dot{x})\;;\quad p \equiv \frac{\partial L}{\partial\dot{x}}. $$ Pedagogically, one first studies Lagrangian Mechanics starting from the least-action principle, and eventually constructs an equivalent Hamiltonian Mechanics framework. But suppose I was a weird physicist who wanted to teach Hamiltonian mechanics first, and then later construct Lagrangian Mechanics. What would be the best way to do this?


this specific problem is something that I knew about for quite a long time but have been able to work around until now.    There is a wall behind the set of bricks, and since both objects are very close to each other, (though not touching), the view presents a choppy and ripped up version of the mesh I need.  Is there a way to prevent this? In the settings of the camera or blender at all? Is it a built in function or is it something I can turn off?  Thank you for any help.

I was following  on creating a watch and noticed that when I rendered the watch, some pieces were messed up.  I'm new to 3D modeling and I've just learned Blender, I can't explain it well, so here's a picture:    Other examples:     I don't know if it's a problem with my World texture, the object, or the object's texture/material, so I can't even guess how to fix it. What causes this? Is it possible to fix it?


I was wondering if given a huge Latex \documentclass[oneside]{book} is it possible to compile a specific range of pages, for example pages 11-35, to a PDF?  I want to compile a single chapter without having to copy and paste content, and move relevant packages into the new file.  I use Kile as my IDE.  Thanks in advance.

I am writing a large document with several chapters and I would like to work on each chapter separately. In my main.tex I include the chapters either like   \include{chap1.tex}  \include{chap2.tex}  \include{chap3.tex}   or   \input{chap1.tex}  \input{chap2.tex}  \input{chap3.tex}   I think \include is preferable if I want things to be referenced and cited correctly? but doing it the \include way latex main.tex I don't get any dvi output whereas with \input things compile fine to dvi. What's going wrong here?  I would then like to use \includeonly (or \excludeonly ) to work on individual sections of the document whilst maintaining the referencing etc.  A mwe can be handy:  \documentclass[a4paper,10pt]{article} \includeonly{chap1}  \begin{document}   \include{chap1}   \include{chap2}   \include{chap3} \end{document}


Can we change a HDD NTFS partition into a ext4 partition, without to loss any?  How?  Greetings & Blessings from Chile!  Juan

I have 2 TB of data on an NTFS drive which I would like to convert to EXT4 filesystem.  My OS runs on a (comparatively) small 60GB SSD.  Is there any way to convert the filesystem, apart from backing up and reformatting?


I am wondering, if the following is true without any other assumptions and if so, how to prove it:  Let $(M_t)_{t \geq 0}$ be a continuous local martingale on a filtered probability space $(\Omega, \mathcal{F}, (\mathcal{F}_t)_{t\geq 0}, P)$ that satisfies the usual conditions.  If $(M_t)_{t\geq 0}$is square integrable (that is, for all $t\geq 0$ we have $E[M_t^2] < \infty$) then $(M_t)_{t\geq 0}$ is a true martingale.  Thanks for any advice.

I can prove it briefly, but I found a "counter" example. (There must be a mistake in the following words...)  I can prove: X is a continuous local martingale, with $X_0=0$ a.s, then X is $L_2$ bounded iff $E[X]_\infty<\infty$  I can prove: X is a continuous local martingale, if $E[X]_\infty<\infty$, then X is a true martingale.  It seems that we can get: any $L_2$ bounded continuous local martingale is a true martingale.  But there is a "counter" example: If X is a standard Brownian motion in $R^3$, started at $0$,  I can prove (i) $Y_t =1/|X_{1+t}|$ is a local martingale; (ii) Y is bounded in $L^2$; (iii) Y is not a martingale.  Can I say: since Y isn't continuous, therefore Y is bounded in $L^2$, but not a martingale??? But I guess that we can prove Y is continuous almost surely. Is continuous L2 bounded local martingale a true martingale???


Suppose I want to delete all emails older than year 2012 in gmail. Currently, what I do is put Before: 2012 in the search box. However using this method, I have to delete the emails 100 conversations at a time. This is time-consuming and tiring on my finger muscles. How can I delete all emails older than year 2012 in gmail in one stroke?  EDIT: The answer in the possible duplicate no longer works. I am no longer able to select all conversations. Emails have to be selected and deleted 100 conversations at a time.

I'm getting the out-of-storage space error for Gmail:    Since I'm , what's the correct way to delete all e-mails within a label without creating a filter or deleting the label itself?


I am a newbie to this and was wondering how to go about building this shell script:  I have files in directory1 with filenames A1-001.xyz  A29-002.xyz  A82-003.xyz and I wanted to move these based on the 2nd part of the filename e.g. 001  002  003 into directory2 with folder name 001 002 003.  Here is what I have done so far:  for file in /path/to/directory1/** ; do echo "$file" | awk -F '[-]' '{print $2}' | cut -f 1 -d '.' ; done >> dummy.txt   input="dummy.txt" while IFS= read -r file; do echo "$file" | mv "$file" /path/to/directory2/$file ; done    My thinking was putting the output filenames from 1st part into a dummy.txt then reading the filenames and moving it. The 2nd part of the script doesn't seem to be working so are there any suggestions on how to do this?

I have this file/folder scheme:  /Aula   /Aula01   /Aula02 aula-01.1.mp4 aula-01.2.mp4 aula-01.3.mp4 aula-02.1.mp4 aula-02.2.mp4 aula-02.3.mp4   All the mp4 files are located in the root directory (Aula), which contains subfolders called Aula01, Aula02 and so on...  I'd like to move these files to their specific subfolder based on the two-digit number in the middle of the files' name and on the final part of the subfolders' name. Like this:  /Aula   /Aula**01**     aula-**01**.1.mp4     aula-**01**.2.mp4     aula-**01**.3.mp4   /Aula**02**     aula-**02**.1.mp4     aula-**02**.2.mp4     aula-**02**.3.mp4   I've searched around and I've found this script, but my knowledge is too limited to tweak it.  #!/bin/bash for f in *.{mp4,mkv}           # no need to use ls. do     filename=${f##*/}          # Use the last part of a path.     extension=${f##*.}         # Remove up to the last dot.     filename=${filename%.*}    # Remove from the last dot.     dir=${filename#tv}         # Remove "tv" in front of filename.     dir=${dir%.*}              # Remove episode     dir=${dir%.*}              # Remove season     dir=${dir//.}              # Remove all dots.     echo "$filename $dir"     if [[ -d $dir ]]; then     # If the directory exists         mv "$filename" "$dir"/ # Move file there.     fi done   Could someone help me out tweaking it, or helping with a better script for this situation?  Also is there a way to make the script to extract only the two-digits number regardless of the file name scheme, in case it differs from the ones in this example  Thanks!


I installed Ubuntu 32bit because I'm a noob and now I've uninstalled it to install the 64bit version.   After uninstalling I'm left with two new partitions a 80GB and a 26GB from the previous automatic dual-boot installation.   Are these partition sizes OK?    How do I manually install 64bit Ubuntu on these two partitions? Please tell tell me in detail what to put in "Use as:" (ext4 or something else?) and what sort of end to put: / or /home or /boot. On which partition.

I'd like to see the full How-To on how to use manual partitioning during Ubuntu installation. The existing guides (at least those I found here) cover only automatic part and leave untouched the manual part (or extremely short and contain no pictures).  I'd like to cover such situations:     If your disk contains other systems:


In my undergraduate complex analysis textbook, it claims that Cauchy Riemann equations is not a sufficient condition for the existence of derivative. Intuitively, I do not understand why this is true, as if you satisfied $$u_x=v_y$$ $$u_y=-v_x$$  it implies that both $$f_x \;\; and\;\; f_y$$ exist and therefore $f$ should be differentiable   Any hint would be much appreciated

Is following contradictory?  "Then $f = u + iv$ is complex-differentiable at that point if and only if the partial derivatives of $u$ and $v$ satisfy the Cauchy–Riemann equations (1a) and (1b) at that point. The sole existence of partial derivatives satisfying the Cauchy–Riemann equations is not enough to ensure complex differentiability at that point."  - [1, second paragraph]  They say that $f$ is complex-differentiable iff partial derivatives of $u$ and $v$ satisfy C-R equations, but still it is not enought to ensure complex differentiability at that point.  So do you need extra conditions as wikipedia says or not for $f$ to be complex differentiability? Can you give me example, where function satisfy C-R equations, but is not Complex differentiable at certain point?


When you level up you get some free goodies, but what happens to those if your backpack happens to be full at that time?   Are the new goodies lost? Are some (random) items in your backpack discarded or can you choose which ones? Or something else?

There's a default limit of 350 items in the bag (even though you can expand it through the shop). I am currently level 6 and have already ~250 items in my bag. I haven't done any battles yet, as all the gyms in my area are too strong for my pokémon at the moment. So I have a lot of Pokéballs, Heals and Revives that I don't need right now.  What happens once my bag is full? Will additional items go into a temporary overflow bag? Will I just lose them? Will they replace older items?  I'm afraid I will lose the valuable items gained through a level-up. Should I throw away items to avoid that? If so, what should I throw out first? Heals and Revives, as I don't need them right now? Or will they become too valuable later on and I should rather throw out some Pokéballs as those are the most common items to receive from a Pokéstop?  TL;DR: What happens with items that exceed my bag size limit and what is the best strategy to avoid losing valuable items?


Can anyone direct me to some beginner tutorials so I can learn the basics of Ubuntu 14.04 and what to configure/install?  Furthermore, any good tutorials for installing/configuring LAMP?

I set up a new VPS instance of Ubuntu and am wondering what the easiest way is to get up and running with a basic LAMP stack (i.e. which packages are required, which configuration options need to be tweaked, if any, etc.).


I recently installed Ubuntu 14.04 LTS Trusty Tahr on my laptop.   Its default Desktop Environment was Unity. I installed gnome-desktop-environment then I could use both unity DE and gnome DE on my laptop.   This made my bootup screen change to the Ubuntu GNOME logo, instead of the vanilla Ubuntu logo.   That's OK, but after some time I thought I will only use Unity, so I removed gnome-shell package and all of its configurations.   Now gnome-shell is removed but still I can see Ubuntu GNOME logo during boot. I can't see the cool Ubuntu logo which I saw at previous when Ubuntu 14.04 was freshly installed.  Is there any way to get back that look on starting up the system?  previous screen image:     I want it back.   my login screen is OK, login screen image:

I wanted to try out different desktop environments so I installed XFCE, KDE, GNOME, etc on top of Unity in Ubuntu 12.04  After a while I decided that I didn't like those other DEs and would stick to Unity. So I changed my default DE to Unity by configuring gdm.  sudo dpkg-reconfigure gdm   Now I am able to choose my DE at login time and all of DEs are working properly.   But the strange thing is that my boot up screen says 'lubuntu', my login screen is KDE, and my desktop is Unity.   How and why is this happening? Why didn't my gdm configuration have any effect? Does login and boot up screen need to be configured separately from the DE?  There are other similar questions here but they are not the same as this one. I do not want to remove the other enviroments I'm quite happy with having a list of DEs to select from. I want to know how to set proper defaults.


I have method:  public ReportBuilder addDiffs(List<String> diffs) {     if (this.diffs == null) {         this.diffs = new ArrayList<>();     }     this.diffs.addAll(diffs);     return this; }   And I want to make unit-test. As I khow it should be like:  @Test public void ReportBuilderTest() {     ReportBuilder builder = new ReportBuilder();     List<String> list = new ArrayList<>();     list.add("some string");      builder.addDiffs(list);      assertEquals(builder.getDiffs(), list)); }   It is example, but my class is inner service and i can't create getter for it. And diffs are private. How to make proper unit-test for this method? Maybe there is a problem with architecture?

How do I unit test (using xUnit) a class that has internal private methods, fields or nested classes? Or a function that is made private by having  (static in C/C++) or is in a private () namespace?  It seems bad to change the access modifier for a method or function just to be able to run a test.


When deriving the OLS estimators, we get to a point where we need to analyze asymptotically the following term:  $n^{-1}\sqrt{n} \sum_{i=1}^n (X_i - \mu_x)u_i$  We'll normally have the weaker assumption that $E(X_iu_i) = 0$, which will imply that $E((X_i - \mu_x)u_i) = 0$.   However, to apply the Central Limit Theorem, we need that the sequence $((X_i - \mu_x)u_i)_{i=1}^n$ be independent and identically distributed (i.i.d).  So my question is, given that the sequence $(u_i, X_i)_{i=1}^n$ is i.i.d by assumption, how can we grant $(u_i, X_i)_{i=1}^n$ is i.i.d?  $E(X_iu_i) = 0$ will only grant uncorrelatedness in this case.

Is the claim that functions of independent random variables are themselves independent, true?   I have seen that result often used implicitly in some proofs, for example in the proof of independence between the sample mean and the sample variance of a normal distribution, but I have not been able to find justification for it. It seems that some authors take it as given but I am not certain that this is always the case.


On Windows 7, the System process is taking up 100% CPU (well 50% on a dual-core) for a rather long time. Its CPU usage doesn’t seem to drop at all.  How can I diagnose this problem? What could be the cause? I don’t see any other problems with the system and am using an up-to-date copy of AVG, so I don’t yet believe it is malware.

I have noticed that from some time my system is freezing and its probably caused by the high CPU usage which is caused by the system process.  All applications I'm running is the Skype, TeamSpeak and Chrome so it definitely shouldnt eat that amount of CPU.  You can see the problem itself and running processes in the screenshot below:    Sometimes CPU usage is reaching 90%, but the average usage is like 40-65%.  My PC parameters:   Windows 8 (customer preview) Intel Core i3 - 2350M 8 GB RAM   I'd appreciate any help attempt! Regards.  --UPDATE--  As the user below posted a great answer, I have noticed that the process that is eating the most CPU in the system is called Arthurx.sys, simple google tells that it's a TPLink driver (an wifi adapter, I have bought like 2 weeks ago!) drivers has been installed from the Windows MSDN, but also tried to install the drivers from the attached CD, but it doesn't help. From the system start, it is using like 5% of the CPU only, but after 2-4 hours of working it is growing up and reaching 40-60% of the CPU usage.  Device name: TPLink WN722N