In some tutorials path is set in ~/.profile however in some other tutorials they use etc/path or ~/.bashrc, can you explain whats the difference and how it works in linux ubuntu. I am sorry for such a basic question but I am using linux for the first time in my life. Or if someone could guide to a tutorial which explains the whole path setting concept.

What are correct places for:   Global environment variables meant to affect all users? User-specific environment variables?


I have two pipe delimited files as below  File 1  TEST|123456 TEST|123457 TEST|123458 TEST|123459 TEST|123460   File 2  TEST|123456|RAY|DOE|| TEST|123457|JANE|DOE|| TEST|123458|ROSE|DAWN|| TEST|123459|GEORGE|BRID|| TEST|123460|RALPH|DOE|| TEST|123461|JOHN|DOE|| TEST|123462|STEVE|SMITH||   File 3 - Desired Output  TEST|123461|JOHN|DOE|| TEST|123462|STEVE|SMITH||   I want to use the first and second column of file1 and file2 as key to getting the unmatched rows from file 2.

Will it be possible to use diff on a specific columns in a file?  file1  Something  123 item1 Something  456 item2 Something  768 item3 Something  353 item4   file2  Another   123 stuff1 Another   193 stuff2 Another   783 stuff3 Another   353 stuff4   output(Expected)  Something  456 item2 Something  768 item3 Another   193 stuff2 Another   783 stuff3   I want to diff the 2nd column of each file, then, the result will contain the diff-ed column but along with the whole line.


I was currently doing the introductory course of python provided by mit on edx. And, the professor is currently teaching the use of functions as objects. I am having confusion in one of the codes where he is defining a function and taking two arguments- one is a list and other is some other function.  def applyToEach(l,f):     for i in range(len(l)):         l[i]=f(l[i])  l=[1,-2,3.4]  applyToEach(l,abs) print(l)   My question is: the changes/modifications in the list is taking place inside the function. So, how they are getting reflected outside the function? According to me, there should not be any changes in the list when I print it because I made all the changes inside the function. I mean that different environments are created for different functions and it worked this way only in the previous exercises and therefore changes are not reflected in our main environment. Correct me wherever I am wrong, because when I am running this code, the modified list is getting printed. So, where I am wrong in the given logic?

I'm trying to understand Python's approach to variable scope. In this example, why is f() able to alter the value of x, as perceived within main(), but not the value of n?  def f(n, x):     n = 2     x.append(4)     print('In f():', n, x)  def main():     n = 1     x = [0,1,2,3]     print('Before:', n, x)     f(n, x)     print('After: ', n, x)  main()   Output:  Before: 1 [0, 1, 2, 3] In f(): 2 [0, 1, 2, 3, 4] After:  1 [0, 1, 2, 3, 4]


I want to align three tikzpictures/pgfplots picture below each other. But they have different ytick labels (varying lenghts/widths). Check the attached screenshot.  Is there a possibility to determine a fixed length/width for the ytick labels?

I have a colorbar in pgfplots and would like to have the y tick labels aligned to the right.  Using  colorbar style={yticklabel style={align=right}}   did not work for me.  The left colorbar shows the default behaviour and the right the wanted bahaviour but with clumsy code (see MWE below).    MWE:  \documentclass{standalone} \usepackage{pgfplots} \pgfplotsset{compat=newest} \begin{document} \begin{tikzpicture} \begin{axis}[ hide axis, scale only axis, height=0pt, width=0pt, colorbar, point meta min=-20, point meta max=20, colorbar style={     height=10cm, }] \addplot [draw=none] coordinates {(0,0)}; \end{axis} \end{tikzpicture} \begin{tikzpicture}%[xshift=2cm] \begin{axis}[ hide axis, scale only axis, height=0pt, width=0pt, colorbar, point meta min=-20, point meta max=20, colorbar style={  yticklabel={$$},     height=10cm, }] \addplot [draw=none] coordinates {(0,0)}; \end{axis}  \foreach \x [evaluate=\x as \xeval using 20-\x*4] in {0,1.25,...,10} \node[anchor=east] at (1.75,-\x) {\pgfmathprintnumber{\xeval}};  \end{tikzpicture} \end{document}![enter image description here][3]


I have a problem for a while now: there is always an extra page at the end of my documents. I notice that this happens when I use simultaneously minitoc and float.  I track this issue down to this minimal code :  \documentclass{report} \usepackage{float} \usepackage{minitoc} \begin{document} \end{document}   I can compile this without any error and it generates an empty page with page number 1. (I use TeX Live 2013 on Linux, and I happens both with LaTeX and pdfLaTeX).  How can I simultaneously create tables of content by chapter and use the [H] option in \begin{figure}[H] ?  Update after egreg answer: here is a new minimal example with some text, that creates always a new page.  \documentclass{report} \usepackage{float} \usepackage{minitoc} \begin{document} \include{ch01} \end{document}   You can put anything in ch01.tex and an extra page will be created.

The minitoc package adds extra page when used with float and lastpage packages. I figured out that this problem can be resolved by loading minitoc package before float and lastpage packages. In LyX the float package is loaded automatically and could not figure out how to force LyX  use minitoc package before loading float and lastpage packages. Thanks in advance for your help.  \documentclass[a4paper,12pt]{book} \usepackage[english]{babel} \usepackage{blindtext} \usepackage{lastpage} \usepackage{fancyhdr} \usepackage{float} \usepackage{minitoc} \begin{document} \dominitoc \tableofcontents \mainmatter \chapter{First Chapter} \minitoc \section{Introduction} \blindtext[1] \section{Material \& Method} \blindmathpaper \chapter{Second Chapter} \minitoc \section{Introduction} \blindtext[1] \section{Material \& Method} \blindmathpaper \end{document}   Edited  It is also working in LyX 2.1.1 if I remove \includepdf[pages={1},scale=1]{Back.pdf} at the end of the document. However if I include \includepdf[pages={1},scale=1]{Back.pdf} at the end of the document it adds extra page. Any thoughts.   Updated  I've narrow downed the problem. My following MWE in .Rnw format adds extra page at the end of document when using minitoc package. Thanks again for your help.  \documentclass[a4paper,12pt]{book} \usepackage{minitoc} \usepackage[english]{babel} \usepackage{blindtext} \usepackage{lastpage} \usepackage{fancyhdr} \usepackage{float} \usepackage{pdfpages} \begin{document} \dominitoc \tableofcontents \mainmatter  \chapter{First Chapter} \minitoc \section{Introduction} << Test >>= 1:50 @  \blindtext[1] \section{Material \& Method} \blindmathpaper \includepdf[pages={1},scale=1]{Back.pdf} \end{document}


Motivation I have learned algebraic topology. In simplical homology, we define $C_k(X)$ as an abelian group freely generated by $k$-dimensional skeleton $X^{(k)}$, and boundary operator $\partial_k$ actually takes the $k-1$ dimensional faces.  So can we do the same on topological (or smooth) manifold? Let $M$ be an $m$-dimensional manifold. $D_k(M)$ consists of $k$-dimensional submanifolds and $\partial_k$ takes their boundary.  Does this concept exist? Is there any reference about this? Any advice is helpful. Thank you.

Consider a manifold $M$, and denote by $\Delta _p M$ the set of all submanifolds of dimension $p$ (with or without boundary) of $M$.   Define $G_pM$ to be the free abelian group generated by $\Delta_p M$, and define $\partial : G _p M \rightarrow G_{p-1} M$ to be the linear extension of the boundary "operator" on manifolds: which takes a manifold $M$ and gives back the boundary $\partial M$.  Does this give rise to an homology theory? If so, is it interesting in any way?


Hi i'm creating a beamer presentation and trying to make my equation beautiful. Is it possible to make color rectangle or circle in align and then write something about that part of the equation.    \begin{align}     \bigwedge\limits_{i,j} E(i,j) = \exists_{m,c} m c^{2}      \tag{Eqn}\label{energy}   \end{align}   I want to create a color box around E(i,j) and then use a pointer/arrow and tell that E(i,j) is a variable representing energy, m represents mass and c represents change. I have tried \colorbox but do not able to get how to point the box and comment. Thanks.

I am preparing a presentation on statistics. I want to include a slide on Bayes' Theorem which says:  p(\theta | D) = \frac{p(D|\theta) p(\theta)} {p(D)}   I want to explain each term using arrows. How can I do this?  I tried to follow this  but my main problem is that I have a fraction. How can I split the fraction?   is exactly what I want to do. Without the last line.


Sorry for the "newbie" question.    When I create an object on the "stage", especially a large object, if I push it far into the back ground, it starts to disappear.  If I push far enough it seems to disappear behind some invisible wall.   Is there a limit to how far the horizon is in Blender? Can that be changed somewhere in settings?  I don't see any obvious settings that effect that.  Thanks for your help!  RonK95

I'm having an odd issue - When I try to zoom in on a detail using my MMB, the "camera" in the 3D view seems to be cutting off the exterior surface of my object and showing me the inside instead. I'd expect this behavior, but only when I was much more zoomed in.  If I zoom out a bit (one click on the scroll wheel) then I can see the exterior as I intend.  Is there any way to adjust this behavior?  Thanks!


I have a data set with two groups of 13 people (condition: sim and con), who get a score for a task (value). They perform a number of tasks at various time points, which form columns Task and timepoint, but for the example below I have just selected a single task and timepoint for simplicity.  I want to formally compare if the distributions are different: they are not normally distributed, and on quick inspection of the raw data and on a plot they are markedly different (not 'science' I know). I am using wilcox.test as a Mann-Whitney U in R.  The problem I am having is the first time I run the test, I try to run it on the tibble, with the condition as the grouping factor, and the W/U value seem to 'disagree' - I've worked though below.  My question is: 1)Clearly there is something wrong with my formula in the first example, but I have tried reading the help and tinkering with subset, but to no avail, so shere have I gone wrong in the first attempt? (ideally I would like to run this a number of times for different Tasks, the missing column, and I don't want to manual have to pull out a vector for each condition for each Task. 2)Which W/U is correct? I would assume it the lower value (3, see below), as it 'agrees' with the p value.  Many thanks in advance.  I'm using R version 3.3.2, in R Studio, and have loaded the tidy verse package.  # A tibble: 26 x 2  condition value   <fctr>           <int>  1       sim              99  2       sim             100  3       con             242  4       con             255  5       con             194  6       sim             135  7       con             504  8       sim             131  9       sim             115 10       sim             159 # ... with 16 more rows   If I run a Mann-Whitney U test on the data:  wilcox.test(value ~ condition, data = q)   I get the follow result:  Wilcoxon rank sum test with continuity correction  data:  value by condition W = 165, p-value = 3.445e-05 alternative hypothesis: true location shift is not equal to 0   However, the U/W value seemed high (above the  on the tables when I checked manually) yet the p value would lead me to reject the null hypothesis. So I separated the tibble into two purely numeric vectors (one for each condition) and repeated the test:  qsim <- q$value[q$condition == "sim"] > qsim [1]  99 100 135 131 115 159 105  77 178 131 120 175 191 130  qcon <- q$value[q$condition == "con"] > qcon [1] 242 255 194 504 545 344 194 198 208 173 349 280  wilcox.test(qsim, qcon)      Wilcoxon rank sum test with continuity correction  data:  qsim and qcon W = 3, p-value = 3.445e-05 alternative hypothesis: true location shift is not equal to 0   The p-value is the same, but the U/W value is lower (and far more in keeping with what I would expect by visually comparing the vectors, let alone plotting them).

What is the practical difference between wilcox.test(x,y, paired=F) and wilcox.test(x~y, paired=F) (i.e. using comma vs. tilde sign) in R, and how to interpret the resulting W-statistic? This should be the same statistical test, but the two methods produce different results.  I have a data frame with 24 rows, each containing information about the sex  and the length of an individual:  mydata<-structure(list(ID = 1:24, Sex = structure(c(2L, 2L, 2L, 2L, 2L,  1L, 2L, 1L, 2L, 1L,1L, 2L, 1L, 1L, 2L,2L, 2L, 2L, 1L, 1L,2L, 2L, 2L, 2L), .Label = c("F", "M"), class = "factor"),Length = c(63.8,79.6, 58, 140, 293, 28.6, 147, 31.3, 33.2, 4.55, 16.4, 19.5, 26.4, 3.34, 29.3, 42.9, 55.6, 122, 30.3, 48.4, 130, 64.7, 93.3, 76.1)), .Names = c("ID", "Sex", "Length"), class = "data.frame", row.names = c(NA, -24L))  I want to explore differences in length between the two sexes using Mann-Whitney U test.  Version 1:  wilcox.test(mydata$Length[mydata$Sex == 'M'], mydata$Length[mydata$Sex == 'F'], paired=F)          Wilcoxon rank sum test  data:  mydata$Length[mydata$Sex == "M"] and mydata$Length[mydata$Sex == "F"] W = 118, p-value = 0.0003698 alternative hypothesis: true location shift is not equal to 0   Version 2:  wilcox.test(mydata$Length ~ mydata$Sex, paired=F)          Wilcoxon rank sum test  data:  mydata$Length by mydata$Sex W = 10, p-value = 0.0003698 alternative hypothesis: true location shift is not equal to 0   They both give me the same P-value, but drastically different W statistics (118 vs. 10). I can't see why this is, or know which one to use for inferences or reporting. Should I not expect to get the same answer from both methods? And how would one go about interpreting the resulting W-statistics?


I have ubuntu 13.04 and windows 7.  I heard that kubuntu is more like windows, so I wanted to try it.  Is it possible to triple boot them?  If it is can you tell me how to.  I have installed ubuntu on a partition.

I would love to triple-boot Windows XP Pro, Ubuntu 12.10, and Backtrack 5 R3, but is this safe for my harddrive/other OSs on the computer?


i want to add weathering/dirt to the leather armor on a model, but the leather texture is procedural, and i want to use a mostly transparent image texture so i can select where to apply the effect to add the dirt and whatnot, but i cant find out how without the image parts that are painted completely covering the procedural texture

I'm designing this animal-type creature, and want to add a transparent .png image to its face with the face features (object has a subsurf). On the left is the image with the features, on the right is the part of the object where I want it to be.    I tried to import the image as a plane, but matching the shape of the plane with the face didn't work, and the lines of the face left shadows on the head, and could be seen as a different object from some angles (although it's the closest I've gotten yet). It looked like this:    So , I tried selecting the faces of the head that the features should go over, and create a new material for it. Unfortunately, since the .png is transparent, the result produced was this:    (where it's impossible to tell the transparency from a black background default color, and where I wouldn't know where to start to adjust size and position).  I also tried UV mapping, but then the whole object became black with the features repeated all over.   Is it something I have to go into Nodes for? I'm kind of stuck here. Creating a new material and applying it is simple, but applying a material that is an image is a bit more complex it seems... Ideally, I would reproduce the same technique for the adhesive bandage on its arm (seen on the right of image 1).


I have a dataset contains both numerical and non-numerical columns.  I want to use PCA, is there any way to handle both?

I have a dataset that has both continuous and categorical data. I am analyzing by using PCA and am wondering if it is fine to include the categorical variables as a part of the analysis. My understanding is that PCA can only be applied to continuous variables. Is that correct? If it cannot be used for categorical data, what alternatives exist for their analysis?


Let $f(t)=t \sin \frac 1 t$ if $0 < t \le 1$, and $f(t)=0$ if $t = 0$.  Consider the curve $\gamma$ with parametric representation $\phi : [0, 1] → \mathbb{R}^2$ defined by $\phi(t) = (t,f (t))$. Prove that $\gamma$ is a continuous curve which is not rectifiable.  for continuity, do I just show that $t\sin\frac{1}{t}$ is continuous on the interval given? To prove it is not rectifiable, I have to show that length of $\phi$ is infinite. Do I show the integral of the derivative of $t \sin \frac 1 t$ is infinite?

Let $f$ be a function defined on $[0,1]$ by   $$f(x) = { 0, \text{ if } x = 0} $$ $$f(x) = { x \sin \frac 1 x , \text{ if } 0 < x \leq 1} $$  Prove that the curve $\{(x, f(x)) : x \in [0,1]\}$ is not rectifiable.   I'm not sure how to approach this. The general idea seems logical, we're proving that the length of the curve is infinite, but the method seems difficult to find.


Let $C$ is positive oriented $|z|=1/2$ circle.  Calculate $\int_C \frac{e^{1/z^2}}{z-1}dz$  I think I can solve it via using residue. The only singular point is $0$ in there. Should I write Laurent series of $e^{1/z^2}$ in $1<|z-1|< \infty $ neighborhood?  Last, if the circle were $|z|=1$ what should I do in that situation?  Thanks in advance

Find the value of $\displaystyle\int_{|z|=2}\frac{e^{1/z^2}}{1-z}dz$   The first idea I had was to apply Cauchy's integral formula. But can this be done? $e^{1/z^2}$ is not holomorphic on the interior of $|z|=2$. Still, if we would apply this we would obtain:  $\displaystyle\int_{|z|=2}\frac{e^{1/z^2}}{1-z}dz=-2\pi ie$.  Another way I think, is to apply the residue theorem. For $1-z$ has a simple zero at $z=1$ and $e^{1/1^2}\neq 0$, then the residue of $e^{1/z^2}/(1-z)$ at $z=0$ is $-e$. Again we obtain $2\pi iRes(g;0)=-2\pi ie$, where $g=\frac{e^{1/z^2}}{1-z}$.  But again, it seems to me this is not right because $g$ has two singularities, at $z=1$ and $z=0$. What we might do about $z=0$? The answer is not $-2\pi i e$?


How would you solve for the closed form solution of a(n) given the general form of the third order linear homogenous recurrence relation with real constant coefficients.  $a_n=Pa_{n-1}+Qa_{n−2}+Ra_{n−3}$  with the initial terms of a_1, a_2, and a_3  given that the roots of the characteristic equations have  1)two repeated roots and a real root  2)three repeated roots  (can you give answers for both cases please)  When I search the web I get these results  1)$a_n = nAx_1^n + Bx_1^n + Cx_2^n$,for the case when there are two repeated roots  and  2)$a_n = n^2Ax^n + nBx^n + Cx^n$, for the case when there are three repeated roots  Can anyone help derive the closed form of each case in order to get such results?  Please help  I'm new to the system so i didn't quite know how to get the symbols right (sorry) if you're uncertain about anything please ask

How would you solve for the closed term form of $a(n)$ given the general form of the third order linear homogenous recurrence relation with real constant coefficients.  $a(n)-P\,a(n-1)-Q\,a(n-2)-R\,a(n-3)=0$  with the initial terms of a1, a2, and a3  and given that the roots of the characteristic equations have   two repeated roots and a real root three repeated roots   (can you give answers for both cases please)  For second order recurrence relations I know that you can use generating functions to deduce a closed form because it is then expressed as a arithmetic series which can be converted into a closed form.  However in the case of the general term of the third order recurrence relations if I follow the same steps what I did with the second order recurrence relation, instead of getting a simple arithmetic series I seemed to get a second order recurrence relation inside the series.  What am I doing wrong?  or is there a different method of approach in this case?  When I search the web I get these results  S(n) = nAx1^n + Bx1^n + Cx2^n,for the case when there are two repeated roots  and  S(n) = n^2Ax^n + nBx^n + Cx^n, for the case when there are three repeated roots  I just don't know how to get to these results  Please help


When browsing any StackExchange site, my Firefox console displays this warning:     This site makes use of a SHA-1 Certificate; it's recommended you use certificates with signature algorithms that use hash functions stronger than SHA-1.   To be clear, it's not the SE cert that is at fault, but the CA root certificate.  The warning points to  for more information.   Whether one chooses to connect via https or not, this is a concern because of mixed content on the sites, and because the GlobalSign Root CA certificate that is the root for *.stackexchange.com has a weak or insecure signature (SHA1 with RSA). That can currently result in a visible warning, depending on which browser is used. Today, actual functionality is unaffected, but should be expected over time.   () "...expect SHA1 certificates issued after 1/1/2017 may stop working at any time." Internet Explorer will distrust SHA-1 certificates after 2016.  () Same timeline. () Is actively sunsetting SHA-1 support. Sites with end-entity (“leaf”) certificates that expire on or after 1 January 2017, and which include a SHA-1-based signature as part of the certificate chain, will be treated as “secure, but with minor errors”. That refers to SE, currently.   Will you be upgrading to more secure certificates at next renewal?

So it looks like Stack Exchange now supports HTTPS (to some extent). Which is awesome! But there are a few problems, the main one being that some content is delivered over the CDN, which is plain HTTP. This causes browsers to complain about "unsecured content":


I am relatively new to LaTeX and most of my answers have been solved with some quick googling, but this specific problem has left me scratching my head with its specificity.   I am writing a paper and trying to include some hyperlinks, so I imported hyperref which caused many of the citations I used to create the following three errors:    ! Undefined control sequence.\hyper@@link ->\let \Hy@reserved@a\relax@ifnextchar [{\hyper@link@ }{\hyp... ...ies them out \cite{Griff_1997, Natura2000} ! Argument of @@cite has an extra }.\par ...ies them out \cite{Griff_1997, Natura2000} ! Paragraph ended before @@cite was complete.\par ...ies them out \cite{Griff_1997, Natura2000}   My preamble is defined as:  \documentclass[titlepage]{article} \usepackage[utf8]{inputenc} \usepackage{geometry} \usepackage{graphicx}  \usepackage{titlepic} \usepackage{apacite} \usepackage{setspace} \usepackage{textcomp} \usepackage{gensymb} %to wrap the urls in the references \usepackage[hyphens]{url} %\usepackage{multicol} \usepackage{listings} \usepackage{hyperref}   \font\myfont=cmr12 at 28pt  \font\myfontini=cmr12 at 20pt \font\myfontinini=cmr12 at 18pt  \geometry{left=2.5cm,right=2.5cm,top=2.5cm,bottom=2.5cm}   With an example of the first created error being   \begin{document}  Mediterranean temporary ponds (MTPs) are bodies of water under 10 hectares which  exist across southern Europe as ephemeral habitat and home to many creatures  which have evolved to the annual cycle which dries them out \cite{Griff_1997,  Natura2000}.  \bibliographystyle{apacite} \bibliography{testref}  \end{document}   and my bibtex for those two entries being   @report{Natura2000, author = {Ernesto Ruiz}, title = {Management of {N}atura 2000 habitats $*$ {M}editerranean temporary ponds 3170}, institution = {European Commission}, year = {2008}, OPTlanguage = {EN}, url = {https://ec.europa.eu/environment/nature/natura2000/management/habitats/pdf/3170_Mediterranean_temporary_ponds.pdf}, }  @article{Griff_1997, author = {Griffiths, R. A.}, title = {Temporary ponds as amphibian habitats}, journal = {Aquatic Conservation: Marine and Freshwater Ecosystems}, volume = {7}, number = {2}, pages = {119-126}, doi = {10.1002/(SICI)1099-0755(199706)7:2<119::AID-AQC223>3.0.CO;2-4}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/\%28SICI\%291099-0755\%28199706\%297\%3A2\%3C119\%3A\%3AAID-AQC223\%3E3.0.CO\%3B2-4}, year = {1997} }   Perhaps it is just something small that I am not noticing, but I would appreciate any help in this matter. Thank you!

I would like to edit my document but I have a compile error somewhere between the \href and the apacite but can't locate it. I've tried blocking out code and taking out references, with varying results.  \documentclass[a4paper,12pt]{article} \usepackage[english]{babel} \usepackage[utf8]{inputenc}  % TOC, Citations, Refereneces, and Appendicies \usepackage{apacite} % \cite{ref1,ref2} %Warning - unsupported tocstyle code \usepackage[tocindentauto]{tocstyle}     \renewcommand{\thesection}{\Roman{section}}      \renewcommand{\thesubsection}{\arabic{subsection}.}     \renewcommand{\thesubsubsection}{\roman{subsubsection}.} %\usepackage{hyperref} %\urlstyle{same} %\hypersetup{ %   colorlinks=true, %   urlcolor=cyan, %   linkcolor=blue, %   citecolor=green, %   filecolor=magenta, %   pdftitle={Sharelatex Example}, %   pdfpagemode=FullScreen, %} \usepackage[toc,page]{appendix}  \begin{document}    ...to be installed \cite{church13,hershkowits97}. \bibliographystyle{apacite} \bibliography{bibliography} \end{document}   Here are the bibliography.bib entries then  @ARTICLE{church13,    author       = {K.H. Church and H. Tsang and R. Rodrigiguez and P. Defembaugh and R. Rumpf},    year         = 2013,    title        = {Printed circuit structures, the evolution of printed circuit boards},    journal      = {Circuit Insight},    volume       = {},    number       = {},    pages        = {},    howpublished = {},     url          = {http://www.808multimedia.com/winnt/kernel.htm}, }  @ARTICLE{hershkowits97,    author       = {N. Hershkowits and R.A. Breun},    year         = {1997},    title        = {Diagnostics for plasma processing (etch plasmas) (invited)},    journal      = {Review of Scientific Instrumentation},    volume       = {68},    number       = {1},    pages        = {880--885},    howpublished = {}, }


I somehow have added buttons for Shut Down, Reboot and Logout into the app launcher in Ubuntu. This is a pretty fresh install of Ubuntu and it wasn't there when I started. If I had to pinpoint one moment this started, I would say it MIGHT be when I accidentally tried to install Unity Tweak Tool not realising I am using a GNOME desktop (it was late, I was tired...). This did result in a bunch of things being installed like Rhythmbox which I have since removed, but these buttons can't be removed as far as I can tell. Has anyone seen this before? Can you suggest what might remove these useless buttons?

I’m new to Ubuntu. I don't know where the log out, reboot and shut down icons in my application list came from. I just need to remove this from here.


Has Lucas ever given any reason to think the name "Millennium Falcon" is an indirect reference to US military aviation FALCON codes?  From  we see that FALCON 1000 means "Cool it, the Chaplain's here" or, , "Cool it the Padre is here".  Note that religion is a common StarWars subtext, and the Millennium Falcon is often trying to escape the "Father".  Also, I could have sworn I remember Han saying "Cool it" at some point but I can't find any proof of that.  Somewhat related to  but that seems to be asking for a in-universe answer, whereas I want a behind-the-scenes answer.

I'm particularly interested in how the "Millennium" part pertains to the ship itself. It wouldn't hurt to explain the "Falcon" part either though.


Is there an equivalent to the yum "whatprovides" option in apt-get?   For example on CentOS  yum whatprovides /usr/share/gdm/themes/TreeFlower/background.png   Tells me   redhat-logos-4.9.99-11.el5.centos.noarch : CentOS-related icons and pictures. Repo        : base Matched from: Filename    : /usr/share/gdm/themes/TreeFlower/background.png   Can I get similar functionality on the command line in Ubuntu?

Simple enough question: is there some shell command (or GUI method) I can use that, given the path to a file on my system, tells me what package put it there? Assuming the file did in fact come from a package, that is.  Bonus question: what if it's a file that isn't installed on my system? Is there, say, a website that will let me look up a file and see what packages, if any, provide it?


We know that Thanos      killed half of the universe, but did he only kill advances lifeforms or simpler ones, too?   Is there any evidence or examples where Thanos cut the line between different lifeforms?  I think Thanos is a really consequent character, so it would be reasonable      to disintegrate half of all life.   There was a question (unfortunately I can't find it anymore), if the event affected half of the population of every planet, or the whole universe. So my follow-up question would be:  Did the event affect half of all lifeforms on a planet as a whole or only half of one specific species separately?      Note that on the latter case the chance that all humans die/live can vary much more, because only one litre of water contains millions (or billions) of animals, so the number of humans is insignificant.

We know that Thanos' plan was to       instantly destroy half of all life in the universe    His plan doesn't appear to apply to lower or non sentient life forms      if it did half the trees in the final Wakanda scene would have disintegrated too   Does his plan apply to all beings more powerful than himself?


New here, so please go easy on me! I've searched other articles on the subject but can't quite find the answer i'm looking for. Hoping someone can help.   Two separate classes, object class and main method. I need to print the object details using toString, but I can't work out how to print the toppings, which are being passed as an array from the main method. The code runs ok, but when I call getToppings() from the toString method, it just prints the id of the array object name, rather than the contents of the array itself.  Can anyone help?  Thanks in advance, Marc  package toString;  /*  * class to represent a pizza object.   */  public class Pizza {    private String name;    private String [] toppings;    private double price;    public Pizza(String reqName, String [] reqToppings, double reqPrice)   {     name = reqName;     toppings = reqToppings;     price = reqPrice;   }    public String getName()   {     return name;   }    public String[] getToppings()   {     return toppings;   }    public double getPrice()   {     return price;   }    public String toString()   {     return "The pizza name is " + getName() + ", the toppings are " + getToppings() + " and the price is £" + getPrice();   }  }  package toString;  public class TestPizza   {     public static void main(String[] args)       {      String[] pepperoni = {"Pepperoni", "minced beef"};     String[] diavalo = {"Pepperoni", "minced beef", "chillies"};     String[] chicken = {"Chicken", "sweetcorn"};      Pizza [] pizzaList = new Pizza[3];      pizzaList[0] = new Pizza("Pepperoni", pepperoni, 6.95);      pizzaList[1] = new Pizza("Diavalo", diavalo, 7.95);     pizzaList[2] = new Pizza("Chicken & Sweetcorn", chicken, 8.95);      System.out.println(pizzaList[0].toString());      System.out.println(pizzaList[1].toString());     System.out.println(pizzaList[2].toString());      }  }

In Java, arrays don't override toString(), so if you try to print one directly, you get the className + '@' + the hex of the  of the array, as defined by Object.toString():  int[] intArray = new int[] {1, 2, 3, 4, 5}; System.out.println(intArray);     // prints something like '[I@3343c8b3'   But usually, we'd actually want something more like [1, 2, 3, 4, 5]. What's the simplest way of doing that? Here are some example inputs and outputs:  // Array of primitives: int[] intArray = new int[] {1, 2, 3, 4, 5}; //output: [1, 2, 3, 4, 5]  // Array of object references: String[] strArray = new String[] {"John", "Mary", "Bob"}; //output: [John, Mary, Bob]


I wanted to mess with some basic commands and one of the commands that I have heard of quite frequently was one that gives someone an item than can break and place entities, blocks or items.  I have looked at some ways to write it and I use this as an example for giving myself a block of stone that can be placed on a chest:  /give Steve stone{CanPlaceOn:["chest"]}   ...but it ends up not working. Can someone explain to me why?

This question was recently split into different questions for each workaround. See   meta posts for more information.   Can you use NBT tags in commands? I’ve tried commands that normally work in Java Edition like: give @s minecraft:planks 30 1 {display:{Lore:["Wooden planks"]}} give @s stone_pickaxe{Unbreakable:1b} give @s item_frame{EntityTag:{Invisible:1b}} summon villager ~ ~ ~ {Offers:{Recipes:[{buy:{id:"emerald",Count:5b},sell:{id:"diamond_sword"}}]}} summon tnt ~ ~ ~ {Fuse:20s}


I have a database table that constantly getting data, more specifically every 30s. I need to select data in user specified days range. For example from 30 days in the past till now and it would return data even if there is no results available.  My table structure:  id | timstamps | io_a | io_b | ______________________________  1 | 2016-12-20 09:50:44| 1 | 0 |   For example i need to select from 2016-11-21 till today - 2016-12-20 and that i would get results even if there is no results.  Example:  2016-12-01 08:50:34 2016-12-02 08:50:34 2016-12-03 08:50:34 etc. till 2016-12-20 09:50:44   SOLVED:  used this query and it worked.  SELECT * FROM table WHERE timestamps > :laikasn AND timestamps < NOW() ORDER BY timestamps

I'm building a quick csv from a mysql table with a query like:  select DATE(date),count(date) from table group by DATE(date) order by date asc;   and just dumping them to a file in perl over a:  while(my($date,$sum) = $sth->fetchrow) {     print CSV "$date,$sum\n" }   There are date gaps in the data, though:  | 2008-08-05 |           4 |  | 2008-08-07 |          23 |    I would like to pad the data to fill in the missing days with zero-count entries to end up with:  | 2008-08-05 |           4 |  | 2008-08-06 |           0 |  | 2008-08-07 |          23 |    I slapped together a really awkward (and almost certainly buggy) workaround with an array of days-per-month and some math, but there has to be something more straightforward either on the mysql or perl side.   Any genius ideas/slaps in the face for why me am being so dumb?    I ended up going with a stored procedure which generated a temp table for the date range in question for a couple of reasons:   I know the date range I'll be looking for every time The server in question unfortunately was not one that I can install perl modules on atm, and the state of it was decrepit enough that it didn't have anything remotely Date::-y installed   The perl Date/DateTime-iterating answers were also very good, I wish I could select multiple answers!


I am thinking of buying an almirah made up of iron and wish to store my laptop inside it. Is it safe ? My concern is that iron being a ferromagnetic material could interfere with the electronics of the laptop. I have learnt from internet that hard disks are safe even near ordinary permanent magnets, but do not know if there are any other parts which might be damaged by proximity to permanent magnets or ferromagnetic materials. Thanks

When I first started using computers, law of the land in computer class was never bring magnets near anything computer related, lest you lose all your data or screw up your monitor.  Now I am pretty sure magnets will still royally mess up a standard hard drive, and I know for a fact they screw up a CRT monitor.  Though I am also pretty sure they do not screw up a LCD monitor?  Now I have my phone which uses magnets to determine if it's docked, and it made me wonder.  Is it the power of the magnet preventing data loss or the sheer fact that whatever memory type in the phone is immune to it?  What about ear buds, as I know those have tiny magnets in them. Are those capable of damaging any electronic device currently in use?  I'm wondering if I'm being paranoid, but I really am not sure what magnets will damage and what they won't!  Is there a list, or rule of thumb for determining what will be hurt by magnets and what won't be?


I have enough security that I was alerted to a PHP backdoor that was uploaded to a WordPress site hosted on one of my servers. It was removed within minutes of being uploaded so no damage was done. No other sites show abnormal file uploads and have been checked for extra files and any files that were recently changed or added. It seems that only one site was affected. I was thinking that maybe the new WP or the theme has a bug that allows someone to upload files.  My main question is how can someone upload a file to a server without FTP or access to WordPress to upload it. I found the first uploaded file in the root of the directory.  I have already scanned and clean the site so now I just would like to figure out how they uploaded the file.

This is a  about Server Security - Responding to Breach Events (Hacking)   See Also:                  Canonical Version I suspect that one or more of my servers is compromised by a hacker, virus, or other mechanism:   What are my first steps? When I arrive on site should I disconnect the server, preserve "evidence", are there other initial considerations? How do I go about getting services back online? How do I prevent the same thing from happening immediately again? Are there best practices or methodologies for learning from this incident? If I wanted to put a Incident Response Plan together, where would I start? Should this be part of my Disaster Recovery or Business Continuity Planning?   Original Version       2011.01.02 - I'm on my way into work at 9.30 p.m. on a Sunday because our server has been compromised somehow and was resulting in a    attack on our provider. The servers access to the Internet   has been shut down which means over 5-600 of our clients sites are now   down. Now this could be an FTP hack, or some weakness in code   somewhere. I'm not sure till I get there.      How can I track this down quickly? We're in for a whole lot of   litigation if I don't get the server back up ASAP. Any help is   appreciated. We are running Open SUSE 11.0.            2011.01.03 - Thanks to everyone for your help. Luckily I WASN'T the only person responsible for this server, just the nearest. We managed   to resolve this problem, although it may not apply to many others in a   different situation. I'll detail what we did.      We unplugged the server from the net. It was performing (attempting to   perform) a Denial Of Service attack on another server in Indonesia,   and the guilty party was also based there.      We firstly tried to identify where on the server this was coming from,   considering we have over 500 sites on the server, we expected to be   moonlighting for some time. However, with SSH access still, we ran a   command to find all files edited or created in the time the attacks   started. Luckily, the offending file was created over the winter   holidays which meant that not many other files were created on the   server at that time.      We were then able to identify the offending file which was inside the   uploaded images folder within a  website.      After a short cigarette break we concluded that, due to the files   location, it must have been uploaded via a file upload facility that   was inadequetly secured. After some googling, we found that there was   a security vulnerability that allowed files to be uploaded, within the   ZenCart admin panel, for a picture for a record company. (The section   that it never really even used), posting this form just uploaded any   file, it did not check the extension of the file, and didn't even   check to see if the user was logged in.      This meant that any files could be uploaded, including a PHP file for   the attack. We secured the vulnerability with ZenCart on the infected   site, and removed the offending files.      The job was done, and I was home for 2 a.m.            The Moral   - Always apply security patches for ZenCart, or any other CMS system for that matter. As when security updates are released, the whole   world is made aware of the vulnerability.   - Always do backups, and backup your backups.   - Employ or arrange for someone that will be there in times like these. To prevent anyone from relying on a panicy post on Server   Fault.


I often get confused which one to use after any. Or are both correct?  Do you have any room available on March 22nd?   Do you have any rooms available on March 22nd?

While I was answering a question on ELL, I got confused with a  from a fellow user. After I indicated that:     "Do you have any idea to prove it?'   is grammatically correct, the OP commented that "ideas" should be used in place of "idea".  The comment befuddled me. I thought until now that "any" should be followed by singular noun and not plural. So I searched Google and saw it's a huge debate going on and there is no end to it. I got no perfect and trustworthy source. So I thought to post the question here.  So what is the right rule? Should singular or plural be used after "any"?


I have this very simple code:    public class Player{     private int x,y,velX,velY,width,height,id;     private boolean isControllable;       public Player(int _x,int _y,int _width,int _height,int _id,boolean _cont){         x = _x;         y = _y;         width = _width;         height = _height;         id = _id;         isControllable = _cont;         if(_cont == true){             addToCont();         }     }      private void addToCont(){         Main.controllable.add(this);     }  }   And this:    public class Main {      public static Render render = new Render();     public static Controlls controll = new Controlls();      public static LinkedList<Player> controllable;      public static void main(String[] args) {         controllable = new LinkedList<Player>();         render.height = 750;         render.width = 1000;         render.RenderWindow();     } }   As You can see I am trying to add this instance of player class to the linked list. But it returns an error:    Exception in thread "main" java.lang.ExceptionInInitializerError Caused by: java.lang.NullPointerException at game.Player.Player.addToCont(Player.java:23) at game.Player.Player.<init>(Player.java:18) at game.Main.Render.<init>(Render.java:28) at game.Main.Main.<clinit>(Main.java:9)   What am I doing wrong?

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


I've flagged many posts for link-only answer when the user posts only a link with no explanation (e.g., to documentation). However, some users return after the fact (I've seen 3-4 hour delays in the past) to add some example code. If my flag still says "active," as in it hasn't been reviewed yet, shouldn't I be able to delete it?

Sometimes you vote to close something and the OP then changes it to fix the issue or issues. You can't take a close vote back though. It would be nice if you could.    With the new Duplicate close changes and the review queues, it's even more important to be able to remove accidental or erroneous close votes: close votes now place a banner on the question (for dupes) or put the question into a queue for other users to look over.  An easy "undo" button could save a bunch of people some time and grief for these accidental/no longer desired close votes.


I'm trying to use <lightning:recordEditForm> in a Lightning Component as an Action Override using lightning:actionOverride interface.  I've overridden the Contact New button with this Lightning Component. Issue is, it opens the form, but it won't pre-populate the AccountId from the source record (as I'm coming from Contact Related List of Account record).   Strange thing that happened was, if I use same code on any other Object (which has a Record Type enabled on it), then I can see in the URL an additionalParams parameter with the parent record's ID value.  So for an object without a Record type, when overridding Standard New action, it does not generate any additionalParams parameter with source record id.  Is this a bug?   And do anyone have a way to make the component work and read the source record value, in actionOverride?  My Lightning Component Code (below):  ContactFormOverride.cmp  <aura:component implements="force:hasRecordId,lightning:actionOverride">     <aura:attribute name="disabled" type="Boolean" default="false" />     <aura:attribute name="saved" type="Boolean" default="false" />     <aura:attribute name="showSpinner" type="Boolean" default="true" />     <aura:attribute name="recordId" type="String" />
         <aura:if isTrue="{!v.showSpinner}">             <lightning:spinner />         </aura:if>         <aura:if isTrue="{!!v.saved}">             Record ID: {!v.recordId}
             <lightning:recordEditForm   onload="{!c.handleLoad}"                                         onsubmit="{!c.handleSubmit}"                                         onsuccess="{!c.handleSuccess}"                                         objectApiName="Contact">                                  <lightning:messages />                  <lightning:inputField fieldName="FirstName" />                 <lightning:inputField fieldName="LastName" />                 <lightning:inputField fieldName="AccountId" />                 <lightning:inputField fieldName="Birthdate" />
                     <lightning:button disabled="{!v.disabled}" variant="brand" type="submit" name="save" label="Save" />
             </lightning:recordEditForm>             <aura:set attribute="else">
Saved! New record id is {!v.recordId}
             </aura:set>         </aura:if>
 </aura:component>   ContactFormOverrideController.js  ({     handleLoad: function(cmp, event, helper) {         cmp.set('v.showSpinner', false);     },     handleSubmit: function(cmp, event, helper) {         cmp.set('v.disabled', true);         cmp.set('v.showSpinner', true);     },     handleError: function(cmp, event, helper) {         // errors are handled by lightning:inputField and lightning:messages         // so this just hides the spinner         cmp.set('v.showSpinner', false);     },     handleSuccess: function(cmp, event, helper) {         var params = event.getParams();         cmp.set('v.recordId', params.response.id);         cmp.set('v.showSpinner', false);         cmp.set('v.saved', true);     } })

I have action override on New Case button which runs our custom component.  As you know, we can create a new Case from different places in org, e.g. from related lists. When creating a Case from related list on Account using standard action in Lightning we have prepopulated AccountId to the lookup field. Is it possible to do the same with custom component? I can't catch the AccountId using force:hasRecordId, because action override redirects me to the new page with custom component where I don't have a context of Account. URL also doesn't contain its Id. What can I do to grab Id of context object and populate it to my component?


I am wondering how can I create a point corresponding to the maximum elevation value of a DEM. I mean, from the DEM I can easily get the maximum elevation. For the sake of a viewshed analysis, I would like to create a point feature corresponding to the spot with maximum elevation. I guess it is simple, but I am having difficulties in finding the right procedure.   I am using arcgis 10.1 (with advanced license).

I am using ArcGIS Desktop 10.1.   I am trying to find the location of the highest value pixel in my Direct Solar Radiation Raster. I can see the extent of the data in my raster but don't know where the highest value pertains to.   Is there a way to simply select pixel with highest value or create a point at highest value?


Let $G:=S_n$ and let $V:=k^n$.   Suppose characteristic of $k$ does not divide $n$.   Define $U:=\{(a_,...,a_n \mid \sum a_i=0\}$  If $\exists$ subspace $U' \subseteq U$ s.t.  $\{e\} \neq U'$ and $gU' \subseteq U'$ $\forall g \in S_n$,   Then $U'=U$.   So $\subseteq$ is clear,   Pick $0 \neq \alpha \in U$, then $\alpha = (a_1,...a_n)$  Since characteristic of $k$ does not divide $n$, we know all entries cannot be equal, furthermore we know all entries cannot be zero and. Where do I go from here to ensure $\alpha \in U'$ ? i.e., $U$ has no nontrivial proper invariant subspaces.

Let $G=S_n$ and let $V$ be the permutation module of $G$ with basis $\{x_1,\ldots,x_n\}.$  Let $\lambda, \mu \in \mathbb{C}$ to allow one to define a $\mathbb{C}G$-homomorphism $\rho:V \to V$ by $$\rho(x_j):=\lambda x_j+\mu\sum_{i \neq j}x_i.$$  By using the above fact or otherwise, how can we prove that $V$ is the direct sum of two non-isomorphic irreducible $\mathbb{C}G$ -submodules?  I tried to prove this by construction. A familiar irreducible submodule in this case is the $1$-dimensional space $U:=\operatorname{span}\{x_1+\cdots+x_n\}$. I intend to find another $(n-1)$-dimensional submodule $W$  which makes $V=U\oplus W$ hold, but it's hard to do so. Is there a way to use the fact instead of a random construction?


I have a scenario:  Previous consultants and users had initially done some work inside our Production org (we have NEVER DEPLOYED to Production - they simply started to do the setup of this company's system there, then days/weeks later, created Sandboxes to continue the effort).  They also installed managed packages that (most) will be used in the system (a couple will not).  There is no "return Production to virgin status" option built into SF.  Does anyone have information on how to properly "empty" a Production org, where Sandboxes are still attached and won't be affected?  I received a general response from SF, but it's not very helpful, especially if we're trying to keep this at an "Advanced SF Admin's" level.     After discussing this further, it is possible to use the Metadata API   to delete the metadata in your Production org (with either the   Force.com IDE, Workbench or ANT deployment tool), and this will leave   your full sandbox unaffected. However, make sure not to refresh the   sandbox after doing so until you've pushed the changes you want from   full sandbox. We would not be able to do this for you but here are   some documentation around these tools and the way to force destructive   changes:              We have one single Object that will stay in Production with associated Chatter and file attachments.  Therefore, I want to "gut" Production, excluding:   Requirements custom object and it's data Chatter (it will ONLY be on Requirements object anyway) Any files uploaded (they will ONLY be on Requirements object)   My initial thought, keeping this out of a Developer level solution, is:   Uninstall ALL packages Use Change Sets to identify anything "custom" per "area" and search-and-delete from there Check for any data in any objects (other than Requirement) and delete (DataLoader/etc)   Is there something better?  Is there a PACKAGE or UTILITY I don't know about that may do this?    UPDATE 2017-06-06: The idea is to keep this out of Developer-level solutions.  [Advanced] Administrator level at the maximum.

I have a production org to which i deployed metadata from dev sandbox using Ant. There is no connection between dev sandbox and production. How can i refresh the production org to a starting point ?


I have a subdomain set up as an online file index. However, I am interested in the best practices for filenames. For example, all of my directories are lowercase, but some of my files contain uppercase letters. Is this standard practice? If not, what are more acceptable options?

I have web directories with upper case letters and site is on Apache server.  Example: www.example.com/ServiceTools/page.htm  I have read that using upper case letters in folder name is bad practice and could cause problem with accessing page and produce 404 pages?  Should I change folder to lowercase and will this have influence on SEO?   www.example.com/servicetools/page.htm


When entering a Q&A at the same time (i.e. "Answer your own question" is checked), if you click the preview box for the answer, a black box is displayed  instead of your answer.  I have tested on HTC One V, Android 4.0.3, SE app v0.1.31.  Screenshot

This is a bit of a more unusual bug to report:    The screenshot above is unedited - the black box is rendered by the Stack Exchange application.  Phone:  running Android 4.0.4 (ICS)


What exactly needs to be escaped in javascript strings.  Or, more specifically, why does   var snaphtml = '<script src="http://seadragon.com/embed/lxe.js?width=auto&height=400px"></script>';   give a syntax error?  Escaping the final <\/script> seems to fix the syntax error, but this doesn't make sense to me as a javascript beginner.

Why do some sites (or advertisers that give clients javascript code) employ a technique of splitting the <script> and/or </script> tags up within document.write() calls?  I noticed that Amazon does this as well, for example:  <script type='text/javascript'>   if (typeof window['jQuery'] == 'undefined') document.write('<scr'+'ipt type="text/javascript" src="http://z-ecx.images-amazon.com/images/G/01/javascripts/lib/jquery/jquery-1.2.6.pack._V265113567_.js"></sc'+'ript>'); </script>


I'm trying to compile the new ACM latex template for my camera ready paper provided in   This template doesn't compile for me and shows following error:  ! pdfTeX error (font expansion): auto expansion is only possible with scalable fonts. \@EveryShipout@Output ...@Org@Shipout \box \@cclv   How can I fix it? It is the template! No changes.  ! pdfTeX error (font expansion): auto expansion is only possible with scalable fonts. \@EveryShipout@Output ...@Org@Shipout \box \@cclv l.121 \end{enumerate} Here is how much of TeX's memory you used: 18161 strings out of 493698 267992 string characters out of 3144404 402755 words of memory out of 3000000 20985 multiletter control sequences out of 15000+200000 54348 words of font info for 144 fonts, out of 3000000 for 9000 1186 hyphenation exceptions out of 8191 60i,11n,94p,1105b,468s stack positions out of 5000i,500n,10000p,200000b,50000s ! ==> Fatal error occurred, no output PDF file produced!   P.S. Interestingly when I use an online compiler such as Sharelatex, it looks fine.  P.S. 2: Thanks to everybody, especially Boris: I re-installed the liberty font on miktex package manager, but that changes made my miktex not work for unknown reasons! I re-installed the whole miktex packages from scratch using ProText and now I can compile :)

I'm using a custom class file.  My main file looks like this:  \documentclass[12pt,a4paper]{thesis} \begin{document} \frontmatter     \pagenumbering{alph}      \pagenumbering{roman}     \clearpage      \cleardoublepage     \tableofcontents     \clearpage     \listoffigures     \clearpage     \listoftables   \mainmatter        \part{test}       \input{test} \end{document}   If I put this in my test.tex it does work:  \chapter{test} \label{chapter:test} test    When it becomes more text (lets say 40x the word "test") I get the error stated in my question title.  To test it I brought my class file down to this:  \ProvidesClass{thesis} \NeedsTeXFormat{LaTeX2e}  % Based on the memoir class \DeclareOption*{\PassOptionsToClass{\CurrentOption}{memoir}} \ProcessOptions \LoadClass{memoir}   I'm totally confused what is causing my error now.  This is the complete error:  ! pdfTeX error (font expansion): auto expansion is only possible with scalable  fonts. \AtBegShi@Output ...ipout \box \AtBeginShipoutBox                                                    \fi \fi


Could someone help me how do I shift text level somewhere inside the map area where I find some comfortable space and insert an arrow to understand what is the label for.

Has anyone been using callout labelling with QGIS, either trunk or stable?   Used for clustered points. That means the point stays where it is, the label maybe moved if required and a leader (plain or pointed) shows the linkage between the label and the point.   How could I do it (you know what I mean, no coding....)?


I have seen that there are some questions about transferring rep to other people and there is obviously the bounty system for that. What I want to know is if I can transfer my own reputation or somehow benefit from one site to another?

Possible Duplicate:             I came from Stack Overflow where I participate more frequently, but now I had an issue that I found would be better to be posted on Server Fault, because configuring LDAP isn't a programming topic. It’s my first posting there, which results in enormous restrictions:    I cannot post my answer I had to remove the links   This is caused by the reputation restrictions. They are justified for users which are new to the system, but as more and more Stack Exchange sites arise to separate topics, I think if you have once understood the idea of Stack Exchange, you don’t have to be educated on each site again.  So I would like to propose a sharing of the reputation across all Stack Exchange sites.


My method keeps returning 0. Can someone help me find why the GPA will not properly compute?  public static double getGPA(String a) {     double value = 0;     double sum = 0;     for(int i = 0; i<a.length(); i++)     {         String grade = a.substring(i,i+1);         if(grade == "A") value = 4;         if(grade == "B") value = 3;         if(grade == "C") value = 2;         if(grade == "D") value = 1;         if(grade == "F") value = 0;         sum += value;     }     return sum/(a.length()+1); }

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


I am trying to create 2 programs that have common code. I need one to add or delete data to/from an array that can be read by the other. Right now I have created a dll that has the class, but my problem is that I don't know how to properly instantiate it so that both programs will be using the same data. Both processes would not be running at the same time.

I have a C++.NET app and a C#.NET app. I would like them to communicate via shared memory.  How is it possible in .NET version 2.0 ?  Mainly want to share a queue object.


I know that there are exactly $2^{\aleph_0}$ Turing degrees, but I am trying to realize the reason: I am convinced there can't be more than $2^{\aleph_0}$ of them, but why can't there be less? I know it should be trivial...

So I know there are precisely $2^{\aleph_0} $ Turing degrees, but is there a proof of this somewhere?


I have Windows 7 and Ubuntu 14.04 on my machine.  It's an average home configuration, and I use it for web development too.    4GB DDR2  300 GB HDD 2,2Ghz Dual core Nvidia 8600GT GPU    Ubuntu boots very fast, much faster than Windows... and uses much less RAM than Windows, but damn man, Ubuntu is laggy as hell, it is nowhere near as smooth as Windows. Firefox is slow  as hell, it works but not nicely like on Windows. I know that Linux is made for servers, but UI is just awful. I don't want my Linux to look fancy like a brand new Mac, I just want it t run as smooth as Windows does. Any tips?  Edit:  Here is my output from terminal when run lspci -nnk | grep -A3 VGA  01:00.0 VGA compatible controller [0300]: NVIDIA Corporation G84 [GeForce 8600 GT] [10de:0402] (rev a1)     Subsystem: CardExpert Technology Device [10b0:1401]     Kernel driver in use: nouveau 03:00.0 Ethernet controller [0200]: Broadcom Corporation NetXtreme BCM5754 Gigabit Ethernet PCI Express [14e4:167a] (rev 02)

What are your tips for improving overall system performance on ubuntu? Inspired by this  I realized that some default settings may be rather conservative on Ubuntu and that it's possible to tweak it with little or no risk if you wish to make it faster.  This is not meant to be application specific (e.g. make firefox load pages faster), but system wide.  Preferably 1 tip per answer, with enough detail for people to implement it.  A couple of mine would be:   Install  (via Software Center or sudo apt-get install preload); Change  value - "which controls the degree to which the kernel prefers to swap when it tries to free memory";   What are yours?  PS: Since this is not intended to have a unique answer but rather, several useful tips, I'm making this community wiki out-of-the-box.


So I have seen previous questions regarding this situation, but all of them appeared to be for fun and silly one shots. What’s different in this case is I’m trying to run a long and intense campaign. The monk of the party recently gained the feat magic initiate and took the Druid cantrip produce flame. He asked me about when he used an unarmed strike while his hand was on fire if the damage from the fire would be added. I wasn’t sure so I just added a small amount of fire damage at the time. After doing f some research I understand that the flaming hand can do other things like holding a sword or a shield, but I don’t know if I should allow him to add damage. By the way I am new to DnD so I’m sorry if I missed something obvious which would answer my question. Thank you for your time.

With the wording of , it seems like you take the cast the spell action to make the flame appear.  You can then attack with it later - it does use the wording "ranged spell attack."  It never addresses what you can do with it otherwise, even though you are still holding a handful of flame.     What if a tavern brawler or a Monk punches with the hand holding the flame, or uses that hand to make a special melee attack (grapple or push?)      Would that be considered a spell attack, or an unarmed strike because the hand is passively holding the flame?  Could you use the flame as an improvised weapon?    Or would it be something else?  Note: I am making a character for a silly one shot. I am not planning on trying to pull this off for a serious campaign, but it is worth trying as a goofy concept. This side note probably won't affect any answers but I wanted to include it anyway.


I need an operative definition of "measuring time in general relativity" that takes in consideration also the presence of strong gravitational fields between me and clock, able to deviate the light that I see coming from the hands in such a way to see an irregular, non periodic movement of them: in special relativity is extremely important to define how someone measure time, because is in the comparison of two measurements that appear the dilation of time, but in general relativity nobody cares about it. Now, if there is no operative definition of "measuring time", how is it possible to say that the proper time is the one "measured" if I don' t have a standard definition?

Apologies in advance for the long question.  My understanding is that in GR, massive observers move along timelike curves $x^\mu(\lambda)$, and if an observer moves from point $x^\mu(\lambda_a)$ to $x^\mu(\lambda_b)$, then his clock will measure that an amount of time $t_{ba}$ given by the curve's arc length; $$   t_{ba} = \int_{\lambda_a}^{\lambda_b}d\lambda \sqrt{-g_{\mu\nu}(x(\lambda))\dot x^\mu(\lambda)\dot x^\nu(\lambda)} $$ will have elapsed where $g_{\mu\nu}$ is a metric on spacetime with signature $(-,+,+,+)$.    Why is this so?     Here is how I would attempt to justify this fact in special relativity with $g_{\mu\nu} = \eta_{\mu\nu}$.  Consider an inertial observer $O$ in $\mathbb R^{3,1}$, and suppose that this observer sees a clock, which I'll call observer $O'$ moving around on a curve $x^\mu(\lambda)$.  If $O'$ were also an inertial observer, then given any event with coordinates $x^\mu$ as measured by $O$, observer $O'$ would measure the coordinates of the event to be $x'^\mu = \Lambda^\mu_{\phantom\mu\nu} x^\nu + x_0^\mu$ for some Lorentz transformation $\Lambda$.  If $O'$ is not inertial, then this is no longer true, and there is some more complicated family of transformations, say $T_\lambda$ between events as seen by both observers.  I would argue, however, that if we were to partition the interval $[\lambda_a, \lambda_b]$ into a large number $N$ of intervals $I_1=[\lambda_a, \lambda_i], \dots, I_N=[\lambda_{N-1}, \lambda_b]$ with $\lambda_n = \lambda_a+n\epsilon_N$ and $\epsilon_N=(\lambda_b-\lambda_a)/N$, then on each interval $I_n$, $O'$ is approximately an inertial observer in the sense that $$   T_{\lambda_n} = P_n + \mathcal O(\epsilon_N), \qquad (\star) $$ for some Poincare transformation $P_n$.  Then we would note that since $O'$ is stationary in his own reference frame, he measures his worldline to have the property $\dot x'^\mu(\lambda) = (\dot t(\lambda), \mathbf 0)$ so that $$   I_{ba}=\int_{\lambda_a}^{\lambda_b}d\lambda \,\sqrt{-\eta_{\mu\nu}\dot x'^\mu\dot x'^\mu} = \int_{\lambda_a}^{\lambda_b} d\lambda \, \sqrt{\dot t^2} = t(\lambda_b) - t(\lambda_a) = t_{ba} $$ On the other hand the integral on the left can be written as a Riemann sum using the partition above, and we can invoke ($\star$) above to get \begin{align}   I_{ba}  &= \lim_{N\to\infty}\left[\sum_{n=1}^N \epsilon_N\sqrt{-\eta_{\mu\nu}\dot x'^\mu(\lambda_n)\dot x'^\nu(\lambda_n)}\right] \notag\\ &= \lim_{N\to\infty}\left[\sum_{n=1}^N \epsilon_N\sqrt{-\eta_{\mu\nu}\dot x^\mu(\lambda_n)\dot x^\nu(\lambda_n)} + \mathcal{O}(\epsilon_N^2)\right] \notag\\ &= \int_{\lambda_a}^{\lambda_b}d\lambda \,\sqrt{-\eta_{\mu\nu}\dot x^\mu\dot x^\mu} \end{align} Combining these two computations gives the desired result.  How do others feel about this argument?  I'm not completely comfortable with it because of the assumption $(\star)$ I made on $T_\lambda$.  I imagine that in GR a similar argument could be made by invoking local flatness of the metric.


I learnt that the permeability of an ion across the membrane contributes to the membrane potential as much as(or even more than) its concentration and electrical gradients. And so far I've made peace with the fact that Sodium, having a very low permeability, doesn't contribute much (through its own movement) to membrane potential despite having a high electrochemical gradient directed towards the cell's interior. Now, the confusing thing is that, if I imagine dumping some sodium ions (with their positive charge) on the cell's exterior, this would affect the electrical gradient of potassium (and in fact other ions)--because more positivity is recorded externally-- making potassium in particular less "ready" to diffuse out of the cell. The result of which would be a depression (that is a more negative value ) of the resting membrane potential. If potassium's extracellular concentration were increased instead, a similar effect would be observed. What exactly is wrong with this reasoning? I'm putting this forward because my Professor mentioned only extracellular potassium ion as having an effect on membrane's resting potential.

Why do we say there is an overall negative charge on the intracellular side of the plasma membrane at rest, and an overall positive charge on the extracellular side when both potassium and sodium are positively charged ions, and they are in relatively equal amounts on either side? It seems to me that both sides should be positively charged, and I can't get my head around it.


My graphics graphics card is a Radeon HD 4250 and ATI has dropped the support for x-server version higher than 1.12. Are there any alternative graphic drivers I can use besides the opensource driver, Gallium 0.4. If not what's the best config I can do to boost performance so that it's similar to the proprietary driver. I'm running Ubuntu 13.10 64bit, and my graphics are: Gallium 0.4 on AMD RS880.

After upgrading to 12.10 quantal, the packaged version of fglrx no longer works. I discovered that this is because there is a separate 'legacy' fglrx driver for the HD 2k-4k series cards, but it is incompatible with the xorg server on 12.10.  This is the most current version of the driver for HD 2000 through HD 4000 series cards. You can't use the non-legacy fglrx driver, but you can use the open-source radeon driver if you prefer your WM compositing to be laggy and your YouTube videos to play like they would on a Pentium MMX series:    Usually this driver can be installed in the following way, necessary because apt-get install fglrx would pull in the non-legacy driver:  wget http://www2.ati.com/drivers/legacy/amd-driver-installer-12.6-legacy-x86.x86_64.zip unzip amd-driver-installer-* sudo sh ./amd-driver-installer-*.run --buildpkg Ubuntu/quantal sudo dpkg -i fglrx*.deb sudo aticonfig --initial -f   If you use a different version of fglrx (for example, a newer 12.9 that doesn't support those cards) then the final command will give you an error no supported hardware detected or something similar. However, everything works at this point and you will get a reasonable xorg.conf:  ... other stuff  Section "Device"         Identifier  "aticonfig-Device[0]-0"         Driver      "fglrx"         BusID       "PCI:1:5:0" EndSection  ... other stuff   At this point you're supposed to reboot and everything will be working with the fglrx driver. However, upon rebooting, you'll be treated to the following errors in Xorg.0.log when fglrx attempts to load:  (EE) Failed to load /usr/lib/xorg/modules/drivers/fglrx_drv.so: /usr/lib/xorg/modules/drivers/fglrx_drv.so: undefined symbol: noXFree86DRIExtension   Some searching around will show that this is a problem with the legacy ATI drivers not supporting xserver 1.13 or newer. () ATI has released a fixed driver for its most recent (HD 5000 series or later) cards, but not for the 'legacy' cards yet. The non-legacy ATI drivers can't be used with the old cards.  What should an Ubuntu user, using one of these HD 2000-4000 series cards, do?    Wait for an updated 'legacy' ATI driver that properly works with xserver 1.13?   Downgrade back to 12.04 Precise, which uses xserver 1.11? Try to downgrade xserver on 12.10 Quantal to 1.12, which could possibly break Unity and GNOME? Forced upgrade to HD 5000 series or later card? (Not possible with integrated graphics...) Some other 1337 action that fixes this problem painlessly?


I'm creating a game in python and I need to get the first player to move round the table after each turn;  I've created a player object which contains a name that remains constant and an order which changes after each turn.  However I can't order by players so that the first player changes each time;  class Player:     def __init__(self):         self.order = 0         self.name = 0   player_count = 10 players = []  for i in range(player_count):     players.append(i)     players[i] = Player()     players[i].name = i     players[i].order = i  #def play_turn():     #pass  for i in range(player_count):     if i + 1 == player_count:         players[i].order = 0     else:         players[i].order += 1 players.order.sort()  #play_turn()   It is saying:  AttributeError: 'list' object has no attribute 'order'

I've got a list of Python objects that I'd like to sort by an attribute of the objects themselves.  The list looks like:  >>> ut [<Tag: 128>, <Tag: 2008>, <Tag: <>, <Tag: actionscript>, <Tag: addresses>,  <Tag: aes>, <Tag: ajax> ...]   Each object has a count:  >>> ut[1].count 1L   I need to sort the list by number of counts descending.  I've seen several methods for this, but I'm looking for best practice in Python.


When we try to execute a stored procedure without sending values to it's required parameter , it gives an error like below.      I wanna know, is there any way to problematically capture the all parameters for a given stored procedure ?  Eg: Parr[] string =  GetSpParameters("StoredProcedureName); //I need to develop the "GetSpParameters" function.  Thanks.

Using C# and System.Data.SqlClient, is there a way to retrieve a list of parameters that belong to a stored procedure on a SQL Server before I actually execute it?  I have an a "multi-environment" scenario where there are multiple versions of the same database schema. Examples of environments might be "Development", "Staging", & "Production". "Development" is going to have one version of the stored procedure and "Staging" is going to have another.  All I want to do is validate that a parameter is going to be there before passing it a value and calling the stored procedure. Avoiding that SqlException rather than having to catch it is a plus for me.  Joshua


I have the following HTML5 document:  <!doctype html>      <meta charset="utf-8">     <meta name="viewport" content="width=device-width; initial-scale=1.0;" />     <link href='http://fonts.googleapis.com/css?family=Open+Sans' rel='stylesheet' type='text/css'>     <link href='css/styles.css' rel='stylesheet' type='text/css'>     <title>My title</title>
some text

text1

text2

item 1

item 2

item 3

         When opening this file in Eclipse I get the following error message: Unknown tag (main)  The version of Eclipse is as follows: Eclipse Java EE IDE for Web Developers, Version: Luna Service Release 1 (4.4.1), Build id: 20140925-1800

I really love Eclipse (PDT)... But i'm developing sites using HTML5 and CSS3 and it mark the HTML5 tags like <nav>, <section> and <article>  as invalid tags (inexistent).  How can I add those new tags to it?  And what about CSS3 rules?  I read something about remove the "invalid tag" check... and that's not what I want. :(


I want to get difference between two dates using the datediff and i want to exclude the weekends.The Code below.  SqlDataAdapter sda = new SqlDataAdapter("SELECT [uSerial] " +", DATEDIFF(dd,[RestartDate],getDate()) as statusDuration ,[cutRefs] " "FROM [dbo].[tblFTTH_Fault_Tool]", conn); DataTable ds = new DataTable(); sda.Fill(ds); GridView1.DataSource = ds; GridView1.DataBind();   kindly assist.

How can I calculate the number of work days between two dates in SQL Server?   Monday to Friday and it must be T-SQL.


I am searching for some directories in find command and if that directory is present then I need to take some action on it. But what is happening is: At some places though the main directories (for which I am searching) hidden .svn directories are present and they are populating as a result of find.   I dont want this .svn dir to be a part of find result.  Here is the find command which i am using :   find <search dir> -mindepth 3 -maxdepth 3 -type d  -regex ".*/V[0-9]+/.*+/.*+")

I'm using the find command on a Mac to search for a folder called test1. Now test1 folder could be present in the .Trash folder also. How do I exclude the .Trash folder from getting reported in search results or basically any folder I wish to exclude?  $ find $HOME  -name test1 -type d /Users/theuser/.Trash/test1 /Users/theuser/test1  /Users/theuser/Downloads/test1    I want the result to be just  /Users/theuser/test1 /Users/theuser/Downloads/test1    I used grep:  find $HOME  -name test1 -type d | grep -v '.Trash'    to filter out the .Trash result, but I'm interested in knowing if using find alone achieves the same results.


When I am experiencing DDoS @10Gbps, if I have BGP router with 10M table entries in it, can I perform search on the offensive network?  I would do this the way, that first I would remove routing to me for first /8 and see if DDoS will stop. And then search this way the source of the DDoS on the complete 32bit address space.  I am not familiar with BGP a lot, not sure how long it propagates and how long such search would take and what would be impact. Also not sure if I can actually prevent some network stop routing to me by their ip numbers I download from RIPE and Arin.  This is particularly for dealing with spoofed attacks, as normal ones can be traced more effectively.  Or how much bandwidth do I need and no of locations to sustain any kind of DDoS in Europe? I can re-route traffic with Route 53 latency based DNS. Recent disclosed strike I read about was around 13Gbps, would 20Gbps be enough?

This is a  about DoS and DDoS mitigation.   I found a massive traffic spike on a website that I host today; I am getting thousands of connections a second and I see I'm using all 100Mbps of my available bandwidth.  Nobody can access my site because all the requests time out, and I can't even log into the server because SSH times out too!  This has happened a couple times before, and each time it's lasted a couple hours and gone away on its own.  Occasionally, my website has another distinct but related problem: my server's load average (which is usually around .25) rockets up to 20 or more and nobody can access my site just the same as the other case.  It also goes away after a few hours.  Restarting my server doesn't help; what can I do to make my site accessible again, and what is happening?  Relatedly, I found once that for a day or two, every time I started my service, it got a connection from a particular IP address and then crashed.  As soon as I started it up again, this happened again and it crashed again.  How is that similar, and what can I do about it?


Let $ A $ be a ring.  Let $ I $ be a preordered set, filtering.  Let $ \Sigma $ a multiplicative subset of $ A $.  Suppose for any given $ i \in I $ a multiplicative subset $ S_i $ of $ A $ contained in $ \Sigma $.  Make the following assumptions:   $ \Sigma = \displaystyle \bigcup_i S_i $ For $ (i, j) \in I^2 $ with $ i \leq j $, elements $ S_i $ become invertible in $ S_ {j}^{-1} A $.   $ \mathcal{D} = ((S_{i}^{-1} A)_{i \in I} \ , \ (S_{i}^{-1} A \to S_{j}^{-1} A)_{i \leq j}) $ is a commutative diagram in the category of filter $ A $ - algebras.  Question :  Show that $ \displaystyle \lim_{\longrightarrow} \mathcal{D} \simeq \Sigma^{-1} A $.  To do that, we need to show that :  $ 1) $ exist morphisms $ \pi_i: S_{i}^{-1} A \to \Sigma^{-1} A $ such that $ \pi_{i + p} f_{i, i + p } = \pi_{i} $.  $ 2) $ for any group $ B $ equipped with morphisms $ \pi_i: S_{i}^{-1} A \to B $ such that $ p_{i + p} f_{i, i + p} = p_{i} $ there exists a unique morphism $ g: \Sigma^{-1} A \to B $ such that $ p_i = g \circ \pi_i $.  But, i d'ont know how to do it.  Thank you in advance for your help.

Let $ A $ be a ring.  Let $ I $ be a preordered set, filtering.  Let $ \Sigma $ a multiplicative subset of $ A $.  Suppose for any given $ i \in I $ a multiplicative subset $ S_i $ of $ A $ contained in $ \Sigma $.  Make the following assumptions:   $ \Sigma = \displaystyle \bigcup_i S_i $ For $ (i, j) \in I^2 $ with $ i \leq j $, elements $ S_i $ become invertible in $ S_ {j}^{-1} A $.   $ \mathcal{D} = ((S_{i}^{-1} A)_{i \in I} \ , \ (S_{i}^{-1} A \to S_{j}^{-1} A)_{i \leq j}) $ is a commutative diagram in the category of filter $ A $ - algebras.  Question :  Show that $ \displaystyle \lim_{\longrightarrow} \mathcal{D} \simeq \Sigma^{-1} A $.  Thank you in advance for your help.


Since we are external observers, an object falling in a black hole should take an infinite amount of time right? If so, what is the answer to my question in the title?

One thing I know about black holes is that an object gets closer to the event horizon, gravitation time dilation make it move more slower from an outside perspective, so that it looks like it take an infinite amount of time for the object to reach the event horizon. It seems like a similar process should slow the formation of the black hole itself: As the star collapses, its gravitational time dilation make itself collapse more slowly. This make me wonder, are what astronomers claim to be black holes really black holes, or are they stars that progressively make themselves more similar to one without actually reaching the stage of having an event horizon?  EDIT: Contemplating one answer, I realize the question is ambiguous. What does finite time mean in general relativity. Here is a less ambiguous question: Is there a connected solution of 3+1 dimensional general relativity with one space-like slice not have a singularity, and another space-like slice having one.


I am trying to install Office 2007 Standard on Windows 8.  When I attempt installation, I get an error saying "The program can't start because MSVCR71.dll is missing from your system."  I've looked and the DLL is not in either the System32 or the SysWOW64 folder.  I've tried downloading the DLL and rebooting, but I got the same error.  I've tried running regsrv32 msvcr71.dll in a command prompt, but I get an error saying "The module msvcr71.dll failed to load.  Make sure the binary is stored at the specified path or debug it to check for problems with binary or dependent .DLL files."  Google told me that the DLL is part of Visual C Runtime.  I've tried reinstalling that, but the DLL did not appear.  I do have DLLs called msvcr100.dll and msvcr110.dll, so it is probably an old version.  I'm not sure what else to try, and Google hasn't been much help.  Office 2007 is listed as  with Windows 8.

msvcr71.dll is missing on Windows 7 and I can't register my dll throw regsvr32  I just can't understand why it can happen Does this dll come with OS, or I can install C++ runtime libraries, or .NET framework to present this file in Windows?  The question is: what (C++ runtime/NET framewor/...) have I to download to present this file in Windows 7?


This is the python function from my pluralsight python class:  def raise_to(exp):     def raise_to_exp(x):         return pow(x, exp)     return raise_to_exp   And the instructor now opens an interactive session and does the following:   from raise_to import raise_to square = raise_to(2), and then goes on to do square(5)   and that produces the result of 25. How or why pass in two distinct arguments? Now I ran a debug on this code and this is what I observed. When I do this:  def raise_to(exp):     def raise_to_exp(x):         return pow(x, exp)     return raise_to_exp  square = raise_to(2)  print(square)   I get : <function raise_to.<locals>.raise_to_exp at 0x00000246D1A88700>, but if I do as the instructor  def raise_to(exp):     def raise_to_exp(x):         return pow(x, exp)     return raise_to_exp  square = raise_to(2)  print(square(5))    I get 25. I would like to know how this works. I know this is referred as a python factory function but how does it work. Is the function storing the first argument for later use with the second argument passed in?

I've been reading a lot about closures and I think I understand them, but without clouding the picture for myself and others, I am hoping someone can explain closures as succinctly and clearly as possible.  I'm looking for a simple explanation that might help me understand where and why I would want to use them.


Given that all functions in Coq will terminate, it cannot cover the entire $RE$. So what is the class it can achieve? Is it $R$?

Since it does not allow nonterminating computation, Coq is necessarily not Turing-complete. What is the class of functions that Coq can compute? (is there an interesting characterization thereof?)


Let $f:\mathbb{R} \to \mathbb{R}$ be continuous satisfying: $f(x+y) = f(x) + f(y)$. Show $f$ is linear.  What I thought would be simple and still probably is, I'm having trouble with. So to show this function is linear, I have to show it satisfies two properties:  1) for any $x+y \in \mathbb{R}$ that $h(x+y) = h(x) + h(y)$  This one is satisfied, just by definition of the function.  2) for any $x \in \mathbb{R}$ and scalar $c \in \mathbb{R}$ then $h(cx) = ch(x)$  I'm having trouble proving this. Since there is no explicit function which would make this easier I'm left struggling how to apply continuity. I thought perhaps if I said:  "suppose $f$ is continuous at the point $a$. Then by definition:   $\forall \epsilon > 0$ and $\forall a >0$ there exists $\delta > 0$ such that if $|x-a| < \delta \rightarrow |f(x) - f(a)|< \epsilon$.   So I thought if I adapt this definition and instead say $\forall \epsilon > 0$ and $\forall a >0$ there exists $\delta > 0$ such that if $|cx-ca| = |c||x-a| < \delta \rightarrow |c||f(x) - f(a)|< \epsilon$.  I'm not sure that really says anything at all, but it is what i came up with.  Advice on how to proceed?

I need to find all functions $f:\mathbb R \rightarrow \mathbb R$ such that $f(x+y)=f(x)+f(y)$. I know that there are other questions that are asking the same thing, but I'm trying to figure this out by myself as best as possible. Here is how I started out:  Try out some cases:  $x=0:$ $$f(0+y)=f(0)+f(y) \iff f(y)=f(0)+f(y) \iff 0=f(0) $$ The same result is for when $y=0$  $x=-y:$ $$f(-y+y)=f(-y)+f(y) \iff f(0)=f(-y)+f(y) \iff 0=f(-y)+f(y)\iff \quad f(-y)=-f(y)$$ I want to extend the result of setting $x=-y$ to numbers other that $-1$, perhaps all real numbers or all rational numbers. I got a little help from reading other solutions on the next part:  Let $q=1+1+1+...+1$. Then  $$f(qx)=f((1+1+...+1)x)=f(x+x+...+x)=f(x)+f(x)+...+f(x)=qf(x)$$ I understood this part, but I don't understand why this helps me find all the functions that satisfy the requirement that $f(x+y)=f(x)+f(y)$, but here is how I went on:  Thus  $$f(qx)=qf(x)$$ and it should follow that $$f \bigg (\frac {1}{q} x\bigg)= \frac{1}{q}f(x)$$ where $q\not =0$, then it further follows that  $$f \bigg (\frac {p}{q} x\bigg)= \frac{p}{q}f(x)$$ where $\frac{p}{q}$ is rational, and lastly it further follows that  $$f (ax)= af(x)$$ where $a$ is real. Thus functions of the form $f(ax)$ where $a$ is real satisfies the requirement of  $f(x+y)=f(x)+f(y)$.  I don't know how much of what I did is correct\incorrect, and any help would be greatly appreciated. Also is there any way that I can say that functions of the form $f(ax)$ where $a$ is real are the only functions that satisfy the requirement of  $f(x+y)=f(x)+f(y)$? Or do other solutions exist?  Again, thanks a lot for any help! (Hints would be appreciated, I'll really try to understand the hints!)


As you know, Firefox has been update to 57.00 but some extensions doesen't work for me. For that i want to pass 56.00 and i remove Firefox 57.00, after that i download Firefox 56.00 version and lastly i copy Firefox 56.00 folder, to there /usr/local directory.  When i give the firefox command, on command line it's work, Firefox open but there is a no icon launcher.  When i search the Firefox starter icon, i can't found anything.  Now how i can create a launcher for Firefox?  PS: I am not using Unity, i'm using XFCE.

In older versions it was easy to create a launcher on my desktop. All I had to do is right click on my desktop and select the "create launcher" option.  How can I create such launchers now?


I need password that includes special characters that are with OWASP standard   pattern="^(?=.*?[A-Z])(?=.*?[a-z])(?=.*?[0-9])(?=.*?[#?!@$%^&*-]).{8,}$"   Currently my password conditions are:   Length of at least 8 characters long Contain at least 1 lowercase letter [az] Contain at least 1 capital letter [AZ],  Contain at least 1 number [0-9] Contain at least 1 special character (currently only #?! @ $% ^ & * -)   When I try to add more special characters (all 33 according to OWASP) I always get some problems (bad verification or not working)

I am tired of always trying to guess, if I should escape special characters like '()[]{}|' etc. when using many implementations of regexps.  It is different with, for example, Python, sed, grep, awk, Perl, rename, Apache, find and so on. Is there any rule set which tells when I should, and when I should not, escape special characters? Does it depend on the regexp type, like PCRE, POSIX or extended regexps?


I ended up with a folder that cannot be deleted. The issue started out as Windows 7 complained about a deletion I performed in an old recyclebin with a message 'filename too long 434 instead of 256 characters' (or something very similar). I tried lots of things like those mentioned in this very similar question:   But I did not succeed. I succeeded in renaming and removing lots of subfolders but not all of them. This is what's left visibly, a folder from the recyclebin:  C:\RECYCLER\S-1-5-21-842925246-2025429265-682008880-1013\   Inside this folder is another one named com4 but that is only visible to a tool like Total-Commander. I was not able to display this folder com4 by say:  dir *.* /A:s dir *.* /A:h   I find interesting that apparently something is in there because the following command results in: access denied. So Windows 7 recognizes an object but does not reveal or delete it.  rd "\\c:\RECYCLER\S-1-5-21-842925246-2025429265-682008880-1013\com4\   Even though I am using an elevated command prompt and logged in as admin without any limitations (I assume).  Any ideas how to get rid of this folder named com4? Getting rid of anything below c:\RECYCLER is fine as well.

Windows seems to have a length limit on file names when trying to delete, though it won't prevent those files from being created.  Our build process creates a number of temporary files (many build off of a WSDL) that run afoul of this limit.  Our ant script is somehow able to delete them when doing a clean, but sometimes I need to delete the workarea directory (where all the temp files go) without actually doing a full clean from ant.  This is the same errors , but the answers there don't really work for me as I'm dealing with a directory, not a file, and I don't always know what specific files or subdirectories are causing the problem.  And I'm trying to avoid any manual process (other than triggering a single command) to actually delete them.  If I try deleting the directory from Explorer I get the error   Cannot delete [file name]: The file name you specified is not valid or too long.   Specify a different file name   Trying Remove-Item in powershell gives the following error:  Remove-Item : The specified path, file name, or both are too long. The fully qualified file name must be less than 260 characters, and the directory name must be less than 248 characters. At line:1 char:12 + Remove-Item  <<<< -force -Recurse <directory>   Does anyone know of any tools or easy ways to get around this delete error without having to manually find the problem files and move/rename them?


'We are one, a global team that makes/make each other better.'   Which would be the correct?

I'd say Microsoft have a way of bending the rules and I know that McLaren have won the championship. While this sounds strange, I believe it is correct English (sorry, I'm not native).   But when it's a small company, would you still use it this way? Is a company always plural, or are small companies singular? I.e., would you say Bakery Johnson makes fine bread or Bakery Johnson make fine bread? Is it My book seller, Woody's, have moved or is it has moved?


For me that subtracting a negative number becomes addition is currently magic. I have watched and read a number of "explanations" and they all basically boils down to:     -- = +   Which for me is magic!  None of these sources have been able to give me a logical and mentally understandable explanation about how exactly subtracting a negative number becomes addition.  As a frame of reference, the below makes sense:     2 + (-4) = -2   For me this is logical. It that tells that the number to add starts at a minus, a deficit.  However how:     2 - (-4)   becomes     2 + 4   is beyond my current understanding of how math works.  The closest I can get is that negative + negative is somehow turning into positive. But that to me is currently just a magical rule.  I think I have missed something very important here, something that makes what I at the moment see as illogical for others clearly is logical and makes perfect sense.  I would be immensely grateful to the person who will take their own time to explain to me how this works, because right now I am very stuck.

Why subtraction of a negative number from a positive number is addition? Eg: $a - (-b) = a + b$ When looking through the number scale I am unable to relate this, please kindly clarify ?


I was searching "C++ returning array from function" on Google when I noticed that the top two results - Stack Overflow and Tutorialspoint - had exactly the same short description beneath the search result.  I compared the  to the  and see that they're almost the same, but not exact copies.  I read  about what to do if plagiarism is suspected, so I thought to check the  to see how old the Tutorialspoint page is, and found it's been . The Stack Overflow answer is from October 2016.  It seems to me that this answer is on the borderline of Stack Overflow etiquette so, more for my own enlightenment, I'm curious as to what Stack Overflow pros think of this.  In favor of the answerer:   An attempt is made to sculpt the Tutorialspoint example to the question asked Links to other pages seems to be frowned upon in answers, so perhaps the answerer thought this was the best way to share what he found to be a good resource This is the only answer the answerer has given so there's no pattern of these type of answers   Against the answerer:   The top part of the SO answer is word-for-word copied from the Tutorialspoint page There's no link to the Tutorialspoint page The attempt to sculpt the Tutorialspoint example mostly involves renaming variables The answer itself doesn't add anything above and beyond the other 20-someodd answers to the question   Again, I'm mostly curious about how a seeming edge case like this is handled.

How should I act if I discover a user plagiarizing fellow users' posts? What if I find someone plagiarizing external resources without attribution?  See also:


We are a Norwegian family traveling on United from Oslo via Heathrow then Newark to Toronto Pearson. We have almost 90 minutes between the flight from Heathrow landing in Terminal B (20:30) and the flight to Toronto leaving from Terminal C (21:57).    Do we have enough time to catch our flight to Toronto?    Should we have checked in luggage or should we only take handbags in order not to waste time?    What do we have to do in Newark and how long does it usually take?    This will be on a Thursday evening.

I am arriving from Frankfurt(FRA) to Newark(EWR) and I must pass the Customs and Border Control before catching the next flight to Baltimore (BWI). Both flight are on the same ticket by United Airlines (UA51 and UA4775)   Is 2 hours and 45 minutes enough time to catch the next plane, or do I have to expect longer waiting times and should go for a different route? I'll be traveling before the AirTrain starts operating. What is the best way to get from Terminal B to C?  I have heard that there is a transfer shuttle bus that connects the terminals such that you don't need to leave security area. What is the schedule for this bus? I'm not sure about the procedure for arriving from abroad. As far as I understood, I'll need to:  Collect my check-in luggage  Pass border control and customs (Immigration) Transfer from Terminal B to C Check my luggage into Domestic Flight Go through Security Check    Is there a way to optimize this procedure to save time? Can I re-check my luggage in terminal B?  What are my options if I miss the connection? Just go to the UA counter and ask to reserve the next possible flight?


After going from 16.04 to 18.04 I noticed that there are a few things missing (apart from the obvious lack of the useful Alt+alt menu search)   I install Netbeans 9 and when I run it, there is no right click and lock in launch panel... How do I keep it handy in the leftmost launcher? It also has awful simple looking checkboxes and tabs within Netbeans (Java?) but that's another topic. Middle scroll doesn't seem to do anything on the leftmost launcher. You used to be able to jump through all the terminal windows or windows of a certain app with the scroll wheel which is very handy.

I would like to switch between windows using the scroll wheel of the mouse over each app icon in Ubuntu dock, as we could do in Unity, but apparently this doesn't work in Ubuntu 17.10. Is there a way to enable it?   Related:


I have 2 questions   When to use "myself" and "by myself"   Can I write "my{space}self" instead of "myself"?

I get confused with the following. Any explanation would be greatly appreciated.         I can't do it myself.    I can't do it by myself.


How can I change the last edited date of a file? There doesn't seem to be anything like:  chlastediteddate  12/7/12 file   What command can do this? Is there a way to do this without changing what the computer thinks is the date, editing the file, and correcting what the computer thinks is the date?

What's the point of the touch command? I know I can create empty files with it, but so is also the case with echo -n.  Otherwise, why would someone need to change the timestamps of a file? Unless to create the false impression about the age of a file, I don't see any other use, and this one is not a legitimate one (from my point of view).