A valid alternative(s) to siunitx package
avoid space after commas used as thousands separator in math mode
Stop terminal auto executing when pasting a command Right, this is a slightly annoying feature because something this happens, and other times it doesn't, very odd.  I paste a command into the terminal with a view to tweaking its arguments, and sometimes it executes the second I paste it. Sometimes it doesn't.  This ranges from embarrassing ( posting nonsensical comments on an IRC ) to dangerous.   How can I shut this feature off for good? I never, never, never want the terminal to auto execute when I paste to it. Redefining nodata value into zero in QGIS I have an image which I clipped with an AOI polygon. The contour area was set to pixel value = 0 and I have a nodata value of -32768. I want to redefine the nodata value into zero. I used to do this with ArcMap easily in the raster calculator, but in QGIS I don't see how I could do it. Any ideas? Values of $\sum_{n=0}^\infty x^n$ and $\sum_{n=0}^N x^n$ Why does the following hold:  \begin{equation*} \displaystyle \sum\limits_{n=0}^{\infty} 0.7^n=\frac{1}{1-0.7} = 10/3\quad ? \end{equation*}  Can we generalize the above to      $\displaystyle \sum_{n=0}^{\infty} x^n = \frac{1}{1-x}$ ?   Are there some values of $x$ for which the above formula is invalid?  What about if we take only a finite number of terms? Is there a simpler formula?     $\displaystyle \sum_{n=0}^{N} x^n$   Is there a name for such a sequence?    This is being repurposed in an effort to cut down on duplicates, see here: Coping with  duplicate questions.  and here: . Stitch first and edit later or vice versa? I have a set of three images imported in Lightroom 3.6 which I want to stitch into one panorama using Photoshop's CS5.5 Merge to Panorama tool. As I see it I have two options in doing so.   Doing all modifications (colour, brightness, contrast, etc...) first, syncing the changes between the three photos and then stitch them together. Stitching the photos first and then use Lightroom to apply modification to the whole image.   Which of these two methods is considered to be best practice? My request is simple: Many times, there will be a question where some people feel like it should be closed. At the same time, I'll feel like it's a perfectly legit question, and it should therefore NOT be closed. Right now, I have to wait till it gets enough close votes (which it always does for some reason, as soon as 1 or 2 people vote to close, e/o else decides to vote as well) and then vote to re-open. How about, as soon as there's one vote to close, there should be an option to counter the close vote, something like "vote not to close" or whatever. This would then bring the "Vote to close" number down by one. Only when the vote to close outnumbers the vote not to close by 5, that's when a question is indeed closed. Any thoughts? DXF file not to scale in Blender When I open the DXF file in LibreCAD, then it shows the correct size of an object, but when I import that file in Blender, then the size of that object becomes very large. Understanding the -exec option of `find` I find myself constantly looking up the syntax of  find . -name "FILENAME"  -exec rm {} \;   mainly because I don't see how exactly the -exec part works. What is the meaning of the braces, the backslash and the semicolon? Are there other use cases for that syntax? Is there a way to choose a beginning and ending edge and auto select all the edges in between? I have been using Blender for quite a long time and I just want to make sure that there isn't a better way of selecting edges, that I might not be aware of. It is so cumbersome to have to click every single edge when I don't want to select an entire edge loop but a portion of one instead. I was wondering if there is some way in to specify a start edge and an end edge and then be able to auto select every edge in between? Quantum Field Theory from a mathematical point of view I'm a student of mathematics with not much background in physics. I'm interested in learning Quantum field theory from a mathematical point of view.  Are there any good books or other reference material which can help in learning about quantum field theory? What areas of mathematics should I be familiar with before reading about Quantum field theory? Is there any hint of of the first Wizarding War being an international event? Is there any hint that the MoM or anywhere else got support in combating voldemort the first time around? Or is everything completely UK-centric?  I can't remember anyone in the second war being specifically sent from europe to help, even though we see international wizards in book 4. But I don't think all the events of the first war are covered in the books.  So are other bodies like the MoM involved in the first war, or was it isolated in the UK? No such file or directory but I can see it! I'm trying to run a python script, on a headless Raspberry PI using winSCP and get the following error message:  Command '"./areadetect_movie_21.py"' failed with return code 127 and error message /usr/bin/env: python : No such file or directory.   When I try and run from terminal, I get:  : No such file or directory.   I try a similar python script, in the same directory, with the same python shebang, the same permissions and using the same user pi, and it works.  I also do a ls and I can see the file, so I don't know why it will not run. How do I bake a texture using Cycles bake I created a interior scene and  i don't know how to bake a texture using cycles bake. I have a friend who is playing with me on a server we've created. Unfortunately, he is on a  Mac whereas I am on a Windows machine. I told him that I should be able to compile and send a .minecraft folder to him so that we can both play. Unfortunately, he can't find his .minecraft folder where it is supposed to be. Is it hidden and how can I unhide it? Error: the question could not be loaded When I was trying to open  I just added using the iOS app I received this error:     Error The question could not be loaded   Reproduction scenario:   add a question; in my case it didn't open it directly; it doesn't show up in the list yet; I opened my profile and clicked the question; bang! Trying to understand what happens with a brokerage firm's customers when it goes bankrupt (case of study: Lehman Brothers) I'm trying to understand how secure it is to own mutual funds/ETFs, not in terms of market volatility etc., but in terms of judicial security (i.e. what happens to your holdings if the firm goes bankrupt). To understand it, I have read this article about the bankruptcy of Lehman Brothers:  Note: From now on, I'm always referring to investors who own funds/ETFs managed by Lehman Brothers, not by investors who invested in Lehman Brothers or subprime mortgages (e.g. S&amp;P 500 ETF investors). From the above article, what I have understood is that the funds/ETFs managed by Lehman Bros. were shifted to other brokerage firms to be managed by them. Is this what actually happened? Still, what happens with the investors if, hypothetically, no brokerage firm in the world wants to manage these financial products? There exists $C\neq0$ with $CA=BC$ iff $A$ and $B$ have a common eigenvalue Question:  Suppose $V$ and $W$ are finite dimensional vector spaces over $\mathbb{C}$. $A$ is a linear transformation on $V$,  $B$ is a linear transformation on $W$. Then there exists a non-zero linear map $C:V\to W$ s.t. $CA=BC$ iff $A$ and $B$ have a same eigenvalue.  ===========This is incorrect==========  Clearly, if $CA=BC$, suppose $Ax=\lambda x$, then $B(Cx)=CAx=C(\lambda x)=\lambda (Cx)$, so $A$ and $B$ have same eigenvalue $\lambda$. On the other hand, if $A$ and $B$ have a same eigenvalue $\lambda$, suppose $Ax=\lambda x, By=\lambda y$. Define $C:V\to W$ s.t. $Cx=y$, then $BCx=By=\lambda y=C\lambda x=CAx$. But I don't kow how to make $BC=CA$ for all $x\in V$.   ====================================== Wikipedia lists the following pseudocode for HMAC:  function hmac (key, message)     if (length(key) &gt; blocksize) then         key = hash(key) // keys longer than blocksize are shortened     end if     if (length(key) &lt; blocksize) then         // keys shorter than blocksize are zero-padded ('∥' is concatenation)          key = key ∥ [0x00 * (blocksize - length(key))]      end if      // Where blocksize is that of the underlying hash function        o_key_pad = [0x5c * blocksize] ⊕ key      // Where ⊕ is exclusive or (XOR)     i_key_pad = [0x36 * blocksize] ⊕ key       // Where '∥' is concatenation        return hash(o_key_pad ∥ hash(i_key_pad ∥ message))  end function   Why are they there?  How were they chosen?  It seems to me that  $hash(key + hash(message))$ (where + is concatenation) would suffice.    Obviously I'm missing something.  What is it? MySQL Case problem I am trying to run a SQL code (I use MySQL). What I want to do is to set DATE_REACT a value when the first condition is satisfied, and a different value when the first condition is not satisfied. The problem is that the first condition is executed always, even when it shouldn't. What I am doing wrong?  UPDATE BILLS SET STATE = 2, DATE_REACT = CASE  WHEN (DATE_EM &lt;= CURTIME() &lt;= ADDTIME(DATE_EM, '00:02:00')) THEN ADDTIME(CURTIME(), '00:13:00') ELSE ADDTIME(DATE_REACT, '00:13:00') END WHERE STATE = 1; Does $\sum\limits_{k=1}^n 1 / k ^ 2$ converge when $n\rightarrow\infty$? I can prove this sum has a constant upper bound like this: $$\sum_{k=1}^n \frac1{k ^ 2} \lt 1 + \sum_{k=2}^n \frac 1  {k (k - 1)} = 2 - \frac 1 n \lt 2$$ And computer calculation shows that sum seems to converge to 1.6449.  But I still want to know:  Does this sum converge? Is there a name of this sum (or the series $\frac{1}{k^2} $)? Get on what tile has mouse clicked