Upgrade to 18.04 from 16.10 I have an ETL/database server running on a 16.10 system. I get errors when trying to apt install packages so I’d like to upgrade. Is it safe to do so?  It looks like I need to run commands to edit files.   Database has streaming replication and I rsynced all of my files (I hope) to another system.
Can I skip over releases when upgrading? I am currently using Ubuntu 10.04. I know there is a 10.10 release, but can I upgrade directly to 11.04? Could you walk me through the steps please?
I am looking for a story about the future of mankind, in which most people have been enslaved in a virtual reality. It ends with the revelation that the people are just lying there imagining their lives with their heads in a trough of feed.  It explains that chemists began to create compounds that could be released into the air to manipulate citizens - causing them to live, shop, think as desired by whoever was in charge. Eventually these tools got subtle enough that they could simulate reality using just these airborne compounds.  This was clearly a prescient view of what later became computer-based virtual reality fiction. I'm having some trouble understanding cosets.  If I understand it correctly, cosets form a partition. So, if I have $|G:H| = 2$, then $G = H \cup xH$. Right?  In an exercise, I'm asked the following:  "For $G$ group and $H \le G$ such that $|G:H| = 2$, prove that $x^2 \in H$ for any $x \in G$"  If $x \in H$, then $x^2 \in H$ because $H$ is a group. But, if $x \notin H$, then $x \in gH$ for any $g \in G$, right? Then $x^2$ = $(gh)^2$ but I can't see why this is in $H$.  Can you give me some hint? Thanks for stopping by. How to install the latest stable version of Chromium? Is there an easier way to install Chromium than what is described ?  Furthermore, is there an easier way to stay up to date with current Chromium releases rather than having to re-build Chromium each release? (a script which automatically grabs and installs the latest build possibly?).  Related: I was reading through some of the questions and answers here on the Rings of Power and I just wondered why the ring effects, affected different races in a slightly different way.  I know other questions ask and answer some of these things, but I just wondered why the Rings of Power caused greed in Dwarves for ever more amounts of treasure.  It's true that Dwarves loved mining and loved wealth and were built of sturdier stuff than men, but why did the Rings of Power not control Dwarves in the way the other Rings of Power controlled men and why did it produce greed and not invisibility? This question is a sequel of sorts to my  about .  In the paper, the authors performed molecular dynamics (MD) simulations of parallel-plate supercapacitors, in which liquid resides between the parallel-plate electrodes.  The system has a "slab" geometry, so the authors are only interested in variations of the liquid structure along the $z$ direction.  In my previous question, I asked about how particle number density is computed.  In this question, I would like to ask about how the electric potential is computed, given the charge density distribution.  Recall that in CGS (Gaussian) units, the Poisson equation is   $$\nabla^2 \Phi = -4\pi \rho$$  where $\Phi$ is the electric potential and $\rho$ is the charge density.  So the charge density $\rho$ is proportional to the Laplacian of the potential.  Now suppose I want to find the potential $\Phi(z)$ along $z$, by integrating the Poisson equation.  How can I do this?  In the paper, on page 254, the authors write down the average charge density $\bar{\rho}_{\alpha}(z)$ at $z$:  $$\bar{\rho}_{\alpha}(z) = A_0^{-1} \int_{-x_0}^{x_0} \int_{-y_0}^{y_0} dx^{\prime} \; dy^{\prime} \; \rho_{\alpha}(x^{\prime}, y^{\prime}, z)$$  where $\rho_{\alpha}(x, y, z)$ is the local charge density arising from the atomic charge distribution of ionic species $\alpha$, $\bar{\rho}_{\alpha}(z)$ is the average charge density at $z$ obtained by averaging $\rho_{\alpha}(x, y, z)$ over $x$ and $y$, and $\sum_{\alpha}$ denotes sum over ionic species.  The authors then integrate the Poisson equation to obtain $\Phi(z)$:  $$\Phi(z) = -4\pi \sum_{\alpha} \int_{-z_0}^z (z - z^{\prime}) \bar{\rho}_{\alpha}(z^{\prime}) \; dz^{\prime} \; \; \; \; \textbf{(eq. 2)}$$  My question is, how do I "integrate the Poisson equation" to obtain equation (2)?  How do I go from  $\nabla^2 \Phi = -4\pi \rho$ to equation (2)?  In paricular, where does the $(z - z^{\prime})$ factor come from?   Thanks for your time. Given a continuous random variable $X$ and the pdf find.... There is a pattern excercise:  First pattern: We have $X$ and the probability density function is usually:  $$ f(x) = \begin{cases}   {ax+bx^2} &amp;  {0\lt x \lt 1} \\   0 &amp; \text{else}   \end{cases} $$  Then we are given $E|X| = 0.6$   And usually asks to find:  a) $P\{X&gt;0.5\}$  b) $Var(X)$    Second pattern:  $$ f(x) = \begin{cases}   {cx^4} &amp;  {0\lt x \lt 2} \\   0 &amp; \text{else}   \end{cases} $$  Where c is a constant. Find:  a) Mean value of $X$  b) Variance of $X$     Third pattern (it's more like a reverse problem):  We are given $Y= \sqrt{X}$, find it's cumulative distribution function (CDF) and  it's probability density function (pdf).    Update:  The third one is transferred to a .  This is not homework. I'm self-studying and in need of some help. Thank you. How to prevent a background process from being stopped after closing SSH client in Linux Why are z-values replaced with zero after in_memory use in Python? The beamer command \alt&lt;*overlay specification*&gt;{foo}{bar} will insert foo if the current slide is within the given overlay specification, and bar otherwise.  It's equivalent to   \only&lt;*overlay specification*&gt;{foo}\only&lt;*complementary overlay specification*&gt;{bar}   Here is a sample document using it:  \documentclass{beamer} \begin{document} \begin{frame} \begin{align*} y &amp;= \frac{(x^2+1)\sqrt{x+3}}{x-1} \\ \ln y &amp;= \ln (x^2+1) + \frac{1}{2} \ln(x+3) - \ln(x-1) \\ \frac{1}{y} \frac{dy}{dx}       &amp;= \frac{2x}{x^2+1} + \frac{1}{2(x+3)} - \frac{1}{x-1} \end{align*} So \[ \begin{split} \frac{dy}{dx} &amp;= \left(\frac{2x}{x^2+1} + \frac{1}{2(x+3)} - \frac{1}{x-1} \right) \alt&lt;2&gt;{\frac{(x^2+1)\sqrt{x+3}}{x-1}}{y} \end{split} \] \end{frame} \end{document}   This is very useful and saves typing.  But if one of the alternatives is larger than the other, it leads to jiggling slides.    What I would like is a overlay-specification-aware command \altvisible that would take the same amount of space on each slide.  So it would have to insert a box as big as the bigger of the two, and then set the correct material.  So the above document with \altvisible instead of \alt would not jiggle.  Any takers? Seasonal Loan Amortization An example of a sequence of Riemann integrable functions $(f_n)$ that converges pointwise to a function $f$ that is not Riemann integrable. I have been given the example $$ f_n(x)= \begin{cases} 1, &amp; \text{if}\; x\in\{(x_k)_{k=1}^{n}\}, \\ 0, &amp; \text{otherwise.} \end{cases} $$ Here the sequence $(x_k)_{k=1}^{\infty}$ is the sequence that "enumerates" elements of $\mathbb{Q}$. The sequence of functions converges pointwise to $$ f(x)= \begin{cases} 1, &amp; x\in\mathbb{Q}, \\ 0, &amp; x\notin\mathbb{Q}, \end{cases} $$ which isn't Riemann integrable. However, I am not quite convinced that $f_n$ is integrable. I would like some help in seeing how $f_n$ is Riemann integrable. Also, I would like more examples of sequences of Riemann integrable functions $f_n$  that converge pointwise to a function $f$ that is not Riemann integrable. Minor grid in pgfplot not showing when specifying ticks manualy Firstly I would like a minor tick between every major tick in my pgfplots graph (and minor grids). I wrote minor tick num=1 but it doesn't work. I am not using a logarithmic axis so it is unrelated to other questions.  Secondly, why is the tick label "1" missing for each axis? How do I get that to display?     \documentclass{standalone} \usepackage{pgfplots} \begin{document} \begin{tikzpicture}  \begin{axis}[% footnotesize, width=4in, height=4in, axis equal, scale only axis, separate axis lines, grid=both, every outer x axis line/.append style={black}, every x tick label/.append style={font=\color{black}}, xmin=0, xmax=1, xlabel={X}, every outer y axis line/.append style={black}, every y tick label/.append style={font=\color{black}}, ymin=0, ymax=1, ylabel={Y}, minor tick num=1, xtick={0,0.1,...,1}, ytick={0,0.1,...,1}, axis background/.style={fill=white}, legend style={at={(0.97,0.03)},anchor=south east,legend cell align=left,align=left,fill=white} ]  \end{axis}  \end{tikzpicture}% \end{document} I need some help importing MrSID Raster files in QGIS. I am running 2.6.0 on Linux Mint 17. After an internet search I have found a couple of resources that are perhaps outdated. The most promising is found here :    However when I attempted to follow the instructions my terminal and I could not find the file "libgdal-mrsid-src" on either the stable or unstable Ubuntu GIS repos. Has anyone had success or could lead me in the right direction? Margin on child element moves parent element Some questions are getting closed as duplicates - good, the system is working. Unfortunately, some are getting closed as duplicates of other questions which are already deleted. This leaves all 1-9,999 reputation users left scratching their heads when they try to view the duplicate. Even worse, imagine being the author of the question and having your question closed as a duplicate when the original question isn't accessible.  I think something is wrong. Today I undeleted a question (left it closed) since it was referenced in the close-reason for another question. Comments indicated that people were clearly irritated that they could not access the duplicate     [Comment] Ok, who thought it was a good idea to close this as duplicate of a deleted question, which most people cannot even see? For the record, I'm reopening - clearly there's enough interest in this question. – Kobi 14 hours ago   ---   [Comment] The PosibleDuplicate link is broken. Voting to reopen. – Rahul G 7 hours ago   ---   [Flag] Closed as duplicate of a deleted question, fail. Thanks for moderating. – {username removed} 14 hours ago   My undelete-action was short-lived, as a few users returned to delete the post again.  It certainly cannot be desirable to reference posts that the vast majority of users cannot even see, especially when the author of the redundant question cannot see (at the time of writing this, the author has a reputation of 18).  I'm not sure what the solution is to this, but I'd like to hear some ideas.  Questions  Question:  Duplicate of: Ubuntu 18.04 not detecting full RAM size How many actuations are "too many actuations"? Changing plurality in parentheses If a set of parentheses lies between a subject and its verb, and the parentheses contain an substitutive subject whose singularity/plurality disagrees with the original subject, whose singularity/plurality should be chosen for the verb?  In other words, in the following example, should "questions" (and its verb "are") be singular, or should they remain plural as shown?     Many (if not every) questions on this StackExchange are answered.   My intuition tells me that the two words in question should remain in plural forms, since the text in parentheses only interrupts the sentence (and the sentence would be grammatically incorrect if everything in parentheses were removed and the words were in singular form).  On the other hand, when read aloud (assuming one reads the text in parentheses), this has an uncomfortable sound to it, and I've seen others write in what would be the above example's singular-form case, so I'm curious to find out which is correct.  And, thinking about it, I suppose the same question would apply when commas are used in place of parentheses. Take the function  $$ \begin{cases}f(x,y)=(x^2+y^2)/\sin(\sqrt{x^2+y^2}) &amp; \text{when } 0&lt;\lvert (x,y)\rvert&lt;\pi\\   0 &amp; \text{when } (x,y)=(0,0) \end{cases}$$  I got that this function is differentiable at $(0,0)$. I calculated the partial derivatives at $(0,0)$ of which both were $0$ and trying to show the definition of differentiability is not satisfied but I keep getting that it is. Plz help. Can I shrink the transaction log file on a mirror database? This is a followup question to  about why I couldn't shrink the log file on the principal database.  To make a long story short, I setup database mirroring but forgot to make sure the job that backed up the transaction log was running again, and the transaction log grew to almost 60GB.   Since mirroring was set up, this size increase was duplicated on the mirrored server, and eventually took up all the disk space and made the mirror database unusable.  Per  about transaction log maintenance on a mirror database, you can't back up the log on the mirror, but when asked specifically in  about how to shrink an overgrown log file on a mirror database, a  was left that      One way to do this would be to failover to the mirrored database and   do the shrink there. Thoroughly test this out in a non-production   environment to ensure it has the behavior you want/expect.   This seems to suggest that there might be other ways to shrink the log file on a mirror, and this method might not necessarily be safe to do on a production server.  Is there a way to safely shrink the transaction log file on a database mirror?