create an (almost) hexagonal mesh on an ellipsoid
Create hexagonal mesh on 3D Parametric Plot and 3D spheres?
I run sudo apt-get install git-all in Ubuntu 16.04 and see the following in the end  Setting up runit (2.1.2-3ubuntu1) ... start: Unable to connect to Upstart: Failed to connect to socket /com/ubuntu/upstart: Connection refused dpkg: error processing package runit (--configure):  subprocess installed post-installation script returned error exit status 1 dpkg: dependency problems prevent configuration of git-daemon-run:  git-daemon-run depends on runit; however:   Package runit is not configured yet.  dpkg: error processing package git-daemon-run (--configure):  dependency problems - leaving unconfigured No apport report written because the error message indicates its a followup error from a previous failure.                       Errors were encountered while processing:  runit  git-daemon-run E: Sub-process /usr/bin/dpkg returned an error code (1)   I get the error after rebooting my system also. It really blocks my whole system.  I run killall update-notifier. I run sudo apt-get install git-all but  I get the same error message. I run pgrep -a apt but get nothing as output. I run pgrep -a update but get nothing as output.  A bug report about the case .    In Grub, Choose Advanced options > Ubuntu (Upstart) Linux kernel 4.22. Doing the same only in terminal without systemd causes the same error.      Why is this error here with runit? Word for people who don't make their deadline Proving that $\lim\limits_{x \to 0}\frac{e^x-1}{x} = 1$ Prime/Maximal Ideals in $\mathbb{Z}[\sqrt d]$ What's the difference between "these" and "those"? First of all, I'm not a native English speaker, but in school I learned that these is used if referring to something near, and those is used when referring to something far away (temporally or locally). But now I'm sometimes watching English movies and notice sentences like "Have you seen those boots?" while the boots were only centimeters away. Is this just not correct, or have I learned the wrong rules?  Another question is, what if I'm referring to something abstract such as ideas or thoughts so that I can't say if they are far away or not. Should I use those or these?  Edit  So it can't be really wrong in any case if I use these respectively those? Tangent bundle : is a manifold I have studied what a differentiable manifold is, and what a tangent space at a given point is, and read the proof that its dimension is equal to the dimension of the manifold. Here a tangent vector is a derivation on the germs of differentiable functions at a point.  Now I am trying to see that the tangent bundle is indeed a differentiable manifold. I get that for an open set $U$ in Eucliden space, it takes the form $U \times \mathbb R^n$ with the vector $\sum a_i x_i$ giving the tangent vector $\sum a_i \partial /\partial x_i$. Now the book says that it is "obvious" that these glue up and give a differentiable manifold.  I may be stupid; but I will be grateful if somebody can hold my hand through this "obvious" statement. When there are too many linked questions to fit in the sidebar, it shows a link to &quot;see more linked questions...&quot;. Clicking on this link takes you to a front-page type showing only the linked questions. You can then use the tabs to sort by &quot;active&quot; to show the most recently active linked questions. However, the gray popup that appears when new questions are posted shows up for any recent activity, not just activity on the linked questions. Clicking through then updates the list, appending more questions to the top of the list, regardless of whether or not they're linked to the question at hand. To reproduce:  Go to  Wait for activity  Screenshots:   Now obviously this isn't a show-stopper, but I thought it might be worth mentioning.  Update June 2020 This is still relevant.  While sitting on the &quot;linked questions&quot; page for a specific question - in the above screenshot,  - and sorted by newest, when a new question is asked the &quot;1 question with new activity&quot; banner will show up, even if that new question does not link back to the question that you were on. The following MWE compiles (for me)  \documentclass{article}  \usepackage{pgfplots} \pgfplotsset{compat=newest} \usetikzlibrary{external} \tikzexternalize[prefix=figures/externalized/]   \begin{document} \begin{figure}     \centering     \begin{tikzpicture}          \begin{axis}  %           \addplot3[surf,mesh/rows=129,mesh/cols=129,mesh/ordering=y varies] table[x=X,y=Y,z=psi] {figures/data/LidDrivenCavity/Lid_SPIKE_128x128_Re1000_psi.dat};              \addplot3[contour gnuplot,mesh/rows=129,mesh/cols=129,mesh/ordering=y varies] table[x=X,y=Y,z=psi] {figures/data/LidDrivenCavity/Lid_SPIKE_128x128_Re1000_psi.dat};          \end{axis}      \end{tikzpicture}     \caption{ciao} \end{figure} \end{document}   where the data file is . If I de-comment the first \addplot3 and comment the second one, then I get an error. The final part of the log file (the interesting one, I think) is  ===== 'mode=convert with system call': Invoking 'pdflatex -shell-escape -halt-o n-error -interaction=batchmode -jobname "figures/externalized/prova-figure0" "\ def\tikzexternalrealjob{prova}\input{prova}"' ======== \openout3 = `prova.auxlock'.  runsystem(pdflatex -shell-escape -halt-on-error -interaction=batchmode -jobname  "figures/externalized/prova-figure0" "\def\tikzexternalrealjob{prova}\input{pr ova}")...executed.  \openout3 = `prova.auxlock'.   ./prova.tex:22: Package tikz Error: Sorry, the system call 'pdflatex -shell-esc ape -halt-on-error -interaction=batchmode -jobname "figures/externalized/prova- figure0" "\def\tikzexternalrealjob{prova}\input{prova}"' did NOT result in a us able output file 'figures/externalized/prova-figure0' (expected one of .pdf:.jp g:.jpeg:.png:). Please verify that you have enabled system calls. For pdflatex,  this is 'pdflatex -shell-escape'. Sometimes it is also named 'write 18' or som ething like that. Or maybe the command simply failed? Error messages can be fou nd in 'figures/externalized/prova-figure0.log'. If you continue now, I'll try t o typeset the picture.  See the tikz package documentation for explanation. Type  H &lt;return&gt;  for immediate help.  ...                                                l.22    \end{tikzpicture}  ?  PGFPlots: reading {figures/data/LidDrivenCavity/Lid_SPIKE_128x128_Re1000_psi.da t} Runaway argument? {\pgfkeyssetvalue {/pgfplots/execute at begin plot visualization}{}\pgfkeyssetv alue \ETC. ./prova.tex:22: TeX capacity exceeded, sorry [main memory size=5000000]. &lt;argument&gt; ...5e-1],2Y7.753628e-3]}{2Y8.20894\ETC.  l.22    \end{tikzpicture}  If you really absolutely need more capacity, you can ask a wizard to enlarge me.   Here is how much of TeX's memory you used:  20761 strings out of 493054  547383 string characters out of 6134761  5000001 words of memory out of 5000000  23958 multiletter control sequences out of 15000+600000  3640 words of font info for 14 fonts, out of 8000000 for 9000  1141 hyphenation exceptions out of 8191  62i,4n,84p,728b,1519s stack positions out of 5000i,500n,10000p,200000b,80000s ./prova.tex:22:  ==&gt; Fatal error occurred, no output PDF file produced!   similar (or the same) error appears if externalization is not enabled/used.  My TeX distribution is TeX Live on Mac OS X 10.9.5 and I use TeXShop as editor.  Once I (partially) solved a  on Windows+MikTeX+TeXniccenter by modifying/adding options to the command executed when compile button is pressed. I say partially since I actually solved the problem for some data file. Then I experienced the same problem with larger datafile and/or different plots (I don't remember anymore) and didn't find a way out, no matter how much I extended the memory.  What should I do now? I want to boot Ubuntu into recovery mode but there is no grub menu entry allowing me to do so. I pressed e and now I am able to edit boot options. It looks like that:  setparams 'Ubuntu , with Linux 3.6.0-26-generic'  recordfail gfxmode $linux_gfx_mode insmod gzio insmod part_msdos insmod ext2 set root='(hd0,msdos5)' search --no-floppy --fs-uuid --set=root &lt;uuid&gt; linux /boot/vmlinuz-3.5.0-26-generic root=&lt;uuid&gt; ro ipv6.disable=1 quirt splash $vt_handoff initrd /boot/initrd.img-3.5.0-26-generic   The  documentation says:     Boot to the recovery mode even if it is not listed on the menu:         Remove existing kernel options from the linux line and add single      But this sentence doesn't make any sense, maybe the wiki page is broken somehow. How to modify the boot menu to boot directly into recovery mode?  Note: I don't have access to grub config or anything else, only the boot menu edit page is available. How do I install python imaging library (PIL)? How do I install the python imaging library (PIL) on Ubuntu?  I tried doing  sudo apt-get install python-imaging   but now when i run     python selftest.py (a script I got from somewhere on the  website) I get (among other warning messages):  ... *** JPEG support not installed *** ZLIB (PNG/ZIP) support not installed ... *** 1 tests of 57 failed.   Have I somehow messed up the PIL -- how do I fix that?  Is maybe the PIL just fine, but that "selftest.py" is not really the right program for checking to see if PIL is installed properly -- how else can I tell if PIL is installed properly or not?  (I'm using Ubuntu 12.04 LTS "Precise Pangolin").  (What I'm ultimately trying to do is to add a 2D barcode generator to some python code, and all the 2D barcode generators I could find that were written in python all seemed to use the PIL). Icon for pinned tabs in Safari? It would be nice to  for .  As it is, SE kind of stands out (in a not cool way): How long would the conference be for? I want to know if this is grammatically correct " How long would the conference be for?". Annoying Viber notification What is a 'multi-part identifier' and why can't it be bound? I continually get these errors when I try to update tables based on another table. I end up rewriting the query, change the order of joins, change some groupings and then it eventually works, but I just don't quite get it.  What is a 'multi-part identifier'? When is a 'multi-part identifier' not able to be bound? What is it being bound to anyway? In what cases will this error occur? What are the best ways to prevent it?    The specific error from SQL Server 2005 is:     The multi-part identifier "..." could not be bound.   Here is an example:  UPDATE  [test].[dbo].[CompanyDetail]  SET Mnemonic = [dbBWKMigration].[dbo].[Company].[MNEMONIC],                 [Company Code] = [dbBWKMigration].[dbo].[Company].[COMPANYCODE]  WHERE [Company Name] = **[dbBWKMigration].[dbo].[Company].[COMPANYNAME]**   The actual error:     Msg 4104, Level 16, State 1, Line 3 The multi-part identifier   "dbBWKMigration.dbo.Company.COMPANYNAME" could not be bound. reveals x2 code snippets. The first result is to  which has a lot of documentation and explanation, along with some useful discussion underneath.   However, , whilst not containing so much documentation, includes sample code for passing commands such as start, stop and restart. It also creates a PID file which can be handy for checking if the daemon is already running etc.  These samples both explain how to create the daemon. Are there any additional things that need to be considered? Is one sample better than the other, and why? I am trying to print a large quantity (several megabytes) of UTF-8 encoded text which consists of Chinese and Latin characters (and maybe a sprinkling of others). I would like to print it in several columns per page, in a very small, condensed font, preferably with control over line spacing. I'd quite like inter-column lines, but I can live without them. The aim is to print to PDF for transfer, as well as to paper.  I have tried enscript and a2ps, but neither of these support Unicode.  I have also tried paps, but this produces bitmapped outputs which cannot be PDF'd effectively, and also look terrible.  Is there a modern way to print UTF-8 text like this without resorting to something like constructing it manually in Python? Any way to add CSS for a single page/node? I'm cleaning up my big crazy style sheets (possibly pertinent to a future question) and I'm wondering the best way to add custom CSS to a specific node or page. In particular, my work site's home page is a Panel Page and it has a bunch of different styling. Right now the CSS is just included with the main theme style sheet. Is there a way to say, &quot;if this is node Foo, then add foo.css&quot;? Is  what I'm looking for? I might be interested in generalizing this to other nodes/sections/etc, but at the moment I just want to handle this one item. Hamiltonian Cycle Problem At the moment I'm trying to prove the statement:     $K_n$ is an edge disjoint union of Hamiltonian cycles when $n$ is odd.   ($K_n$ is the complete graph with $n$ vertices)  So far, I think I've come up with a proof. We know the total number of edges in $K_n$ is $n(n-1)/2$ (or $n \choose 2$) and we can split our graph into individual Hamiltonian cycles of degree 2.   We also know that for n vertices all having degree 2, there must consequently be $n$ edges. Thus we write $n(n-1)/2 = n + n + ... n$ (here I'm just splitting $K_n$'s edges into some number of distinct Hamiltonian paths) and the deduction that $n$ must be odd follows easily.  However, the assumption I made - that we can always split $K_n$ into Hamiltonian paths of degree 2 if $K_n$ can be written as a disjoint union described above - I'm having trouble proving. I've only relied on trying different values for $n$ trials and it hasn't faltered yet. So, I'm asking:     If it is true, how do you prove that if $K_n$ can be split into distinct Hamiltonian cycles, it can be split in such a way that each Hamiltonian cycle is of degree 2? How do you iterate backwards through an STL list? What are the differences in targets, and when should I switch to one? So I get the 4 options for target selection are:   Attackers Badges Randoms K.O.s   What I don't understand is the pros/cons for selecting each one, and what situations would make each one useful.  Things like Badges and K.O. makes no sense to start off with because nobody starts off with badges, and nobody is going to start off near death unless they are purposely trying to lose (by hard dropping int he same position). I've tried the strategy then of just sticking with Attackers, but then I all of sudden get wave after wave of garbage late into the game.    So it begs the question -- what are the differences in target choices, and how can I use that to my advantage to become a Tetris 99 champion?