Hi i am getting the error below when i try and update my ubuntu server through command line:     Reading cache      Checking package manager      Cannot upgrade      An upgrade from 'zesty' to 'bionic' is not supported with this tool.   i used the following commands to try and update:  sudo apt update  sudo apt dist-upgrade  sudo apt autoremove do-release-upgrade   im trying to upgrade from 17.04  my sourcelist content is:  ## EOL upgrade sources.list # Required deb http://archive.ubuntu.com/ubuntu/ artful main restricted universe multiverse deb http://archive.ubuntu.com/ubuntu/ artful-updates main restricted universe multiverse deb http://archive.ubuntu.com/ubuntu/ artful-security main restricted universe multiverse  # Optional deb http://archive.ubuntu.com/ubuntu/ artful-backports main restricted universe multiverse
I've installed ubuntu 17.04 and I want to upgrade it to 18.04. When I tried to do:   sudo do-release-upgrade   I got a message saying An upgrade from 'zesty' to 'bionic' is not supported with this tool. Need inputs to proceed on this.  sudo do-release-upgrade Checking for a new Ubuntu release Your Ubuntu release is not supported anymore. For upgrade information, please visit: http://www.ubuntu.com/releaseendoflife  Get:1 Upgrade tool signature [819 B]                                            Get:2 Upgrade tool [1,257 kB]                                                   Fetched 1,258 kB in 0s (0 B/s)                                                  authenticate 'bionic.tar.gz' against 'bionic.tar.gz.gpg'  extracting 'bionic.tar.gz'  Reading cache  Checking package manager  Can not upgrade   An upgrade from 'zesty' to 'bionic' is not supported with this tool.
YA coming-of-age fantasy series, protagonist keeps pigs I lost a series books during a move and I'm thinking I might like to get them for my son.  They are about a teenage orphan who lives with a (sort of) wizard who's primarily known for his prize pig. There is a "bad guy" but he doesn't do much - he starts off the action in one by scaring the pig, and the boy has to chase after it. He goes on several such adventures, notably one to "find his true nature" that ends with him staring into a pool.  I suppose it could be the early books of , but I'm pretty sure I read them in the 1980s, not 90s, and title seems wrong. And unlike the Wiki description, in the series I'm thinking of, there's no real magic to speak of - its "out there" but does not seem to be part of the action that I recall. How is the no-cloning theorem compatible with the fact that fan-out gates work? I have some difficulty with understanding no-cloning theorem. Simply speaking, according to the theorem, it is not possible to copy a quantum state.  On the other hand, CNOT gate can be used as so-called fan-out gate which purpose is to copy one qubit to another one, previously in state $|0\rangle$.  It seems that these two facts negate each other.   My question: How is no-cloning theorem compatible with the fact that fan-out gate works? I showed up here to write a perfectly normal rant about misaligned pixels, and there's a big fat checkbox cluttering up the "Ask" page:    WHAT THE EEEEK IS THIS NEW ABOMINATION? ANOVA assumption normality/normal distribution of residuals How do you find time period as a function of time for a simple pendulum that is in the form of a hollow sphere that is filled with mercury and there is a hole in the bottom through which the mercury is constantly falling at a fixed rate? I tried creating a function for the time period to check how it varies with the mass of mercury, but I had too many variables.   EDIT: This question was a concept based multiple choice question in my homework book. The option were time period becomes erratic, time period increases, time period decreases, time period first increases then decreases. Should we have a subjective version of every Stack Exchange site? Homeomorphism is bijective Here is my question:  Is a homeomorphism, that is, a continuos function whose inverse function is also continuous, always bijective? Show that the operator norm is submultiplicative We had in our lecture on numerical analysis the following: Let $\mathrm{Lin}(X,Y)$ be the set of all linear maps $X\rightarrow Y$. Let $A\in\mathrm{Lin}(\mathbb R^l,\mathbb R^n)$ and $B\in\mathrm{Lin}(\mathbb R^n,\mathbb R^m)$ and $\|C\|_{op}:=\max_{\|x\|\leq1}\|C(x)\|$. Then our lecturer followed $\|A\circ B\|_{op}\leq\|A\|_{op}\cdot\|B\|_{op}$. So he didn't prove it and so I've tried it by my own. My attempt: $$\begin{aligned} \|A\circ B\|_{\mathrm{op}} &amp;= \max_{\|x\| &lt; 1}\|(A \circ B)(x)\| \\ &amp; \leq \max_{\|x\| &lt; 1} \|A\|_{\mathrm{op}} \|B(x)\| \\ &amp;= \|A\|_{\mathrm{op}} \max_{\|x\|\leq1}\|B(x)\|\\ &amp;= \|A\|_{\mathrm{op}}\|B\|_{\mathrm{op}} \end{aligned}$$ But this seems too easy. I am really interested in a nice proof so anybody could help? Thanks a lot! I'm always wondering: most GNU/Unix tools take options in the form "minus something", sometimes followed by an argument. What if you got a file named minus something?  $ ls -f $ rm -f $ ls -f $ mv -f abc mv: missing destination file operand after `abc' Try `mv --help' for more information. $ cat -f cat: invalid option -- 'f' Try `cat --help' for more information.   or  $ ls -ohello.c $ gcc -ohello -ohello.c gcc: fatal error: no input files compilation terminated.   This is just out of curiosity; I don't have a use case for this. How to connect a GUI button to function? Find a parabola touches the line $y=x$ and $y=-x$ at $A(3,3)$ and $B(1,-1)$ If a parabola touches the line $y=x$ and $y=-x$ at $A(3,3)$ and $B(1,-1)$, then find the focus, axis of the parabola and its directrix.   What I thought: Since the 2 tangents are perpendicular,the origin must lie on the directrix and the line joining A and B is a focal chord. Don't know how to proceed from here.. Is there a single word for "moving unhinderedly"? Do trees really get a large share of their mass from the carbon in the air? I remember hearing that trees and other plants actually obtain a large amount of their mass from the carbon floating in the air, not the ground beneath them. Does the makeup of air actually contain enough carbon to support this theory, and is a tree's surface area actually large enough to obtain the amount of carbon it needs directly from the air? Performance evaluation of auto.arima in R and UCM on one dataset I started evaluating and comparing some methods in forecasting. I used Price of dozen eggs in US, 1900–1993, in constant dollars in the R software FMA package. I held out the last 10 years for assessment of forecast. Below are the results:  I used auto arima method in the R software. Obviously the results are way off. Am I doing something incorrect ? Below is the forecast. It does not recognize the declining trend.     I also used an unobserved components model (UCM) and obtained a good forecast,  as below.   Without outliers/level shifts there are very large standard errors and therefore wide confidence bands.  After some iterative work, below is the output with outliers/level shifts (I know I'm overfitting here) but it did a pretty good job in forecasting; there are also narrow confidence bands.    In looking at just this example the UCM seems to predict the hold-out sample more accurately than auto.arima.  Why is auto.arima not providing a reasonable forecast?  Are state space models/UCMs better for forecasting long range?  Are there any benefits of using one method over other? What fallacy dismisses a conclusion because supporters give invalid arguments for it? Two footnotes in a heading, only one is displayed at the end of the page I'm adding two footnotes to a section heading:  \documentclass{article} \usepackage[english]{babel} \usepackage[utf8]{inputenc} \usepackage[T1]{fontenc} \usepackage{lipsum}  \usepackage[stable]{footmisc}  \usepackage{titlesec}  \begin{document} \section{test \footnote{This is footnote no1.} \footnote{This is footnote no2.} } \lipsum[4] \end{document}   The heading will have both of the footnotes, but at the end of the page only the second is displayed. The problem appears to be \usepackage{titlesec}, because it works fine without it.    Stuff I specified in \usepackage{titlesec}:  \renewcommand\thesection{\arabic{section}}  \renewcommand\thesubsection{\arabic{subsection}}  \renewcommand\thesubsubsection{\arabic{subsubsection}}  \titleformat{\section}[block]{\Large\scshape\centering}{\thesection}{1em}{}  \titleformat{\subsection}[block]{\large\scshape}{\thesection.\thesubsection}{1em}{}  \titleformat{\subsubsection}[block]{\large\scshape}{\thesection.\thesubsection.\thesubsubsection}{1em}{}   Thanks in advance! C# and USB HID Devices Should I use the past tense with did? Should I use the past tense with did? For example, I was to say:     The important question is: Did they knew what it means or not?   Or should I say:     The important question is: Did they know what it means or not?   In other words: Should I use past tense with did?  I looked at this:    but it didn't really answer my question. How can I instantiate a generalized hash function? I've come across a bunch of "strange" hash function notations, such as the following ones and now I don't know how to choose / instantiate them.  Can you please explain me what this notation means and how I can actually instantiate such a hash function?  The notation in question: $$H_1:\mathcal M \rightarrow \mathbb F_p$$ $$H_2:\mathcal M \rightarrow \mathbb Z_n^*$$ $$H_3:\mathcal M \rightarrow \{0,1\}^l$$ $$H_4:\mathcal M_1\times ...\times \mathcal M_k\rightarrow \mathcal S$$  where $\mathcal M\in\{\mathbb F_p,\mathbb Z_n^*,\{0,1\}^*,\mathbb G,...\}$ where $\mathbb G$ is a generic (but there instantiated) group and $\mathcal S\in\{\mathbb F_p,\mathbb Z_n^*,\{0,1\}^l\}$ C# Mono - Low Level Keyboard Hook