a step away from hibernate! I'm having trouble enabling my hibernate feature. I have installed Ubuntu 12.04 LTS 64bit using Wubi on my Asus N53SN hybrid laptop ( Intel + Nvidia). After Updating through ubuntu Update manager AND turning off my Nvidia card using Bumblebee, I no longer have an issue with suspending (aka standby, right?) my laptop and the laptop fan running at the full speed all the time. Oh and I also installed Jupiter and have set it on power saver ( CPU temp= 48 centigerades. is it ok?). any ways, I thought these were important to know in order for my problem to be solved.  So when I tried to hibernate using uswsusp, it seemed like ubuntu was doing some things, the colorful screen went black with white texts, it didn't turn off; but everything went back to normal (but there were no sound/wireless problem). having a 8gb ram, I checked my swap size and I thought that I should increase it. I did that using this code that is available on the WubiGuide:  sudo su swapoff -a cd /host/ubuntu/disks/ mv swap.disk swap.disk.bak dd if=/dev/zero of=swap.disk bs=1024 count=2097152 mkswap swap.disk swapon -a free -mrm swap.disk.bak   (I thought 2gbs is ok since I won't have 2gb of applications running to take ram memory. maybe I am wrong here.) then, I try : sudo s2disk but I get:     s2disk: Could not use the resume device (try swapon -a). Reason: No such device   I do what he (!) asks, but nothing happens. I again try to run s2disk, but I get the same error.  can you help me out? I think since I have no trouble with with suspend then I am just one step away from having hibernate.  EDIT: I came across this question   I didn't think that this would interfere. So there is no way to hibernate with a swab FILE?
How do I enable hibernation on Wubi? I installed Ubuntu on my Windows 7 Sager laptop using Wubi. Hibernate (i.e. suspend to disc) is not an option from the power icon, only suspend, shutdown, etc. Hibernate is also not an option from my battery/lid close options. I understand that hibernation is disabled by default in Ubuntu 12.04. I tried running pm-hibernate but I get the following message:  Looking for splash system... none  s2disk: Snapshotting system   and then the computer just hangs with a black screen. According to the documentation  if this fails then I can't enable hibernate but it offers no help in making pm-hibernate succeed.  Could swap be my problem? It looks like I have very small swap:  user@ubuntu:~$ cat /proc/swaps Filename                Type        Size    Used    Priority /host/ubuntu/disks/swap.disk            file        262140  0   -1   The advice on  is only for the author's set up (e.g. I don't have an Ubuntu install disk since I used Wubi) and he says that 'INFO: This will not work for 12.04, resume from hibernate work differently in 12.04.'  Any advice? I really need to get hibernate working to use my laptop as a, er, laptop.  Thanks
Torsion elements of a group aren't necessarily a subgroup In a question from an exam in an undergraduate group theory course, we were asked to prove or disprove that the set of all Torsion elements of a group is necessarily a subgroup.  I knew that the set of Torsion elements is closed under the inverse operation, but was later told that it is not closed under multiplication, therefore disproving the claim. However, I couldn't find any examples of a group $G$ and two elements $a,b$ such that both $a$ and $b$ have a finite order, but $ab$ doesn't. I know that for this to happen $G$ must be an infinite and non-Abelian group, but still couldn't find a valid example.   What are some examples of groups/elements fulfilling the aforementioned property? Why is the second order perturbative correction to the ground state energy always down? How do you post to an iframe? How do you post data to an iframe? In C# why can't a conditional operator implicitly cast to a nullable type I would like to create a XeLaTeX layout where  multicol's columns (two in this case, no figures, text only) are tilted where they meet. The lines still should be ordinary lines below each other, but the start/end points of each line should glide a bit each line for it to look something like this:  xxxxxxxxxx  xxxx xxxxxxxxxx  xxxx xxxxxxxxx  xxxxx xxxxxxxxx  xxxxx SECTION   xxxxxx xxxxxxxx  xxxxxx xxxxxxx  xxxxxxx xxxxxxx  xxxxxxx xxxxxx  xxxxxxxx xxxxxx  xxxxxxxx xxxxx  xxxxxxxxx xxxxx  xxxxxxxxx xxxx  SUBSECTION xxxx  xxxxxxxxxx   So not the whole column is tilted, but one gets narrower while the other one gets wider.  I've seen examples using \parshape, but those I found are based that one counts lines and more or less manually defines the shape. I also would need that LaTeX keeps the multicol functionality (page breaks, text flow, ...) and does this automatically on each page for a longer chapter.  How do I create such a layout? If multicol is not easy to mix with this layout, what would be an alternative? How does linear regression use the normal distribution? In linear regression, each predicted value is assumed to have been picked from a normal distribution of possible values. See below.  But why is each predicted value assumed to have come from a normal distribution? How does linear regression use this assumption? What if possible values are not normally distributed? How to get this only in small letters (lowercase)? I used the following code to give out the category name (without link) in a single post.  How would it be possible for the category name that is given out to only appears in small letters ?  I just think this has to be made with substring, but I dont get it :) Could somebody please help me :)  &lt;?php foreach((get_the_category()) as $category) { echo $category-&gt;cat_name . ' '; } ?&gt; We are doing the research about applying remote sensed data on hydro logical model . After delineating, the river basin from DEM data using Argis9.3, We have to map the remote sensed data derived from products like PERSIANN. Our task now is to create the grid with the same resolution with the available remote sensed data( for example 0.25degree x 0.25 degree). and have a certain corner that matches with the obtained data.   Does anyone know how to deal with our problem? Using launchd to update MacPorts I want to use launchd to update my MacPorts tree periodically (i.e. port selfupdate.  I have created /Library/LaunchDaemons/org.macports.selfupdate.plist:   $ ls -l /Library/LaunchDaemons/org.macports.selfupdate.plist -rw-r--r--  1 root  wheel  669  8 Nov 12:49 /Library/LaunchDaemons/org.macports.selfupdate.plist   It has the following contents:   &lt;?xml version="1.0" encoding="UTF-8"?&gt; &lt;!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"&gt; &lt;plist version="1.0"&gt; &lt;dict&gt; &lt;key&gt;Label&lt;/key&gt; &lt;string&gt;org.macports.selfupdate&lt;/string&gt; &lt;key&gt;ProgramArguments&lt;/key&gt; &lt;array&gt;     &lt;string&gt;/opt/local/bin/port&lt;/string&gt;     &lt;string&gt;selfupdate&lt;/string&gt; &lt;/array&gt; &lt;key&gt;StandardOutPath&lt;/key&gt; &lt;string&gt;/var/log/org.macports.selfupdate.log&lt;/string&gt; &lt;key&gt;StandardErrorPath&lt;/key&gt; &lt;string&gt;/var/log/org.macports.selfupdate.err&lt;/string&gt; &lt;key&gt;RunAtLoad&lt;/key&gt; &lt;true/&gt; &lt;key&gt;StartInterval&lt;/key&gt; &lt;integer&gt;604800&lt;/integer&gt;&lt;!-- 1 week --&gt; &lt;/dict&gt; &lt;/plist&gt;   I've loaded it and verified that it's loaded:  $ launchctl list | grep macports -   78  org.macports.selfupdate   But it doesn't look like it actually run.    $ port info wireshark Warning: port definitions are more than two weeks old, consider updating them by running 'port selfupdate'. wireshark @1.12.8_3 (net) ...   What am I missing? How do I enable hardware virtualization technology (VT-x) for use in Virtualbox? Why are there two Address lines in Address forms? Experience and a quick Google Images search suggests that it's standard to provide two fields for Address/Street. A colleague argues that it's perceived as two alternative addresses, and that the fact that there's only one country, state, zip, phone just makes it more confusing. I tried to think of a good explanation for having two fields but couldn't. To the reason of "there are some very long addresses" he replies "then why don't they use a multiline input field which would make it clearer that it's the same address".  So, what's the reason? And is it only standard for the US or for Europe as well? How can the speed of sound increase with an increase in temperature? Is $x^3+y^3+z^3-1$ irreducible over a field $k$ of characteristic $\neq 3$? Is $x^3+y^3+z^3-1$ irreducible over a field $k$ of characteristic $\neq 3$?   If I can show that $y^3+z^3-1$ is irreducible, I believe I can use Eisenstein's criterion. But I don't see how to show even this.  The other approach on my mind is to show that $k[x,y,z]/(x^3+y^3+z^3-1)$ is an integral domain, but this doesn't seem particularly promising either. How do I combine two lists into a dictionary in Python? "errno 5 - input/output error" when trying to install Ubuntu Today I downloaded Ubuntu for my laptop. It runs great from a bootable USB, but when I tried to install it, I got the following error message: The installer encountered an error copying files to the hard disk:  [Errno 5] Input/output error  This is often due to a faulty CD/DVD disk or drive, or a faulty hard    disk. It may help to clean the CD/DVD, to burn the CD/DVD at a lower   speed, to clean the CD/DVD drive lens (cleaning kits are often    available from electronics suppliers), to check whether the hard disk   is old and in need of replacement, or to move the system to a cooler   environment.     I tried everything to install it on my laptop including redownloading the Ubuntu ISO image, but nothing worked. Can you forgo your readied action to take an opportunity attack instead? Example:   Player 1 uses the ready action to do something when something happens (unimportant) Goblin, decides to charge across the battlefield and attack Player 2, but happens to cross paths with Player 1 possibly provoking an opportunity attack (here lies my question)   Could Player 1 decide to ignore their readied action and use their reaction to attack the goblin? This would of course take up their reaction so they could no longer take their readied action when it triggers.  If so; let's say it is a fireball that was readied (or any spell), would Player 1 be required to drop the fireball spell? They technically cast it as part of their ready action, but I would understand if this would be a downside to using a reaction before their readied action triggered (maybe this should be another question, but please answer it anyway and tell me if I need to create a separate one so you can answer it there too :P). There is  with this exact same prompt which got several down-votes for not showing  their work.  So I'll show what work I've got.  I know being a harmonic function implies satisfying the Mean Value Property, thus what I thought I'd do is consider two arbitrary points in $\mathbb{C}$ and prove that:  $$|u(z) - u(w)|=|\frac{1}{2\pi}\int_0^{2\pi}u(z - re^{i\theta})d\theta - \frac{1}{2\pi}\int_0^{2\pi}u(w - te^{i\theta})d\theta| $$ $$= |\frac{1}{2\pi}\int_0^{2\pi}u(z - re^{i\theta}) - u(w - te^{i\theta})d\theta|$$  Now what I wan't to do is take r and t to infinity and prove this integral goes to zero, but I can't figure out how to do that.  I've used the fact that my harmonic function u is defined on all of $\mathbb{C}$ in taking t and r to infinity but I still need to use the fact that it's bounded.  I also read through the proof of Liouville's Theorem, given as an answer in that other post, which seems intuitively correct but rather un-rigorous.  It actually says that the value in the center of a ball is equal to the average over the ball's volume.  I imagine this can be proven from the average over the boundary since the average over the boundary will not change as you continuously shrink the boundary down to its center. This however would require the difference of two surface integrals, or is there a simpler way?   I was also considering using the Maximum Modulus Principle somehow but I haven't found a way yet.  I've probably made this way more complicated than it has to be, hopefully someone can help me, thanks! =].  Edit: Ok after thinking some more about the accepted answer in that other post, I've decided what I need to do is look at the canonical holomorphic function whose real part is my harmonic function u, and prove that holomorphic function is bounded.  From there I can prove that since it's entire and bounded that it's constant, and from there prove that then its real part must be constant.  So could someone talk a bit about the construction of this canonical holomorphic function? How can I reconnect to a ssh session after a broken pipe? Why should I install hardware drivers if my computer is working fine? I've just installed Windows 7 on my PC.  I went online to look for drivers. For , Foxconn offers LAN drivers, on-board audio drivers, and chipset drivers. And for , Nvidia offers a graphics card driver, obviously.  But then I stopped and wondered... what benefit would I gain from installing them?   The LAN cable is plugged in and I'm online; no problems there.  The on-board audio is working fine.  A quick Google tells me that a chipset is responsible for moving data around my motherboard – which seems to be happening OK!  And my graphics look perfect.    So why should I install the drivers? What would they give me, other than badly designed "management" interfaces, and pointless "notifications" whenever I plug in an audio jack?  If there are different considerations for each of the components – chipset, audio, LAN, and graphics (and any others you think I should be aware of) – please break it down in your answer.     Update: I've had a couple of answers already, saying that I'll get better stability, bugfixes, etc.   Can I slightly expand my question... Can I get all these same benefits if I install the drivers via Windows Update? And if I do this, would I avoid having to install the vendor-specific UIs, which I find so annoying? Pullback of locally free sheaves is locally free states that if $f:X \rightarrow Y$ is a morphism of ringed space, $G$ is a locally free $O_Y$-module, then $f^*G$ is a locally free $O_X$ module.     Suppose that $G$ is a locally free $O_Y$ module, hence it is a free $O_Y|_U=O_U$ module. We have an induced map  $$f^{-1}(U) \rightarrow U$$ given by restriction of morphism of ringed spaces.   Hence, as $\bigoplus O_U \simeq G|_U$, $f^*:Mod(O_U) \rightarrow Mod(O_{f^{-1}(U)})$ is functorial, $f^*(G|_U) = (f^*G)|_{f^{-1}(U)}$, we have isomoprhism,  $$ \bigoplus O_{f^{-1}(U)} \simeq (f^*G)|_{f^{-1}(U)} $$