Static methods can't run other methods?
Static Classes In Java
Is a NVIDIA GeForce with Optimus Technology supported by Ubuntu? I'm searching how to remove the chapter+section number on the theorem numbering with a section counter.  With no section counter it's like:  \newtheorem{thm}{Title} Chapter1 ----Section 1 --------thm 1 --------thm 2 ----Section 2 --------thm 3 --------thm 4 Chapter2 ----Section 1 --------thm 5 --------thm 6 ----Section 2 --------thm 7 --------thm 8   And with the section counter:  \newtheorem{thm}{Title}[section] Chapter 1 ----Section 1 --------thm 1.1.1 --------thm 1.1.2 ----Section 2 --------thm 1.2.1 --------thm 1.2.2 Chapter 2 ----Section 1 --------thm 2.1.1 --------thm 2.1.2 ----Section 2 --------thm 2.2.1 --------thm 2.2.2   And I want numbering my theorems like this:  \newtheorem???????? Chapter 1 ----Section 1 --------thm 1 --------thm 2 ----Section 2 --------thm 1 --------thm 2 Chapter 2 ----Section 1 --------thm 1 --------thm 2 ----Section 2 --------thm 1 --------thm 2   I know it's always a pain to remove such things, thanks for whoever will help me ^^ It's not clear to me how to choose Spells Known when creating a new character at a higher level.  Let's take the Bard as a working example first:  Bard level 2:   Spells Known: 5 Slots per Spell level: 1st &times; 3   Bard level 3:   Spells Known: 6 Slots per Spell level: 1st &times; 4, 2nd &times; 2   I'm interpreting this to mean that, if an existing 2nd-level Bard gains a new level (level 3), he's gaining 1 (one) new spell known. He can then choose the new spell known to be either 1st or 2nd, correct?  What I don't understand then, is the case of creating a new character starting at a higher level; say, creating a new Bard at level 3.  In that case you're forced to choose 6 spells, which must be from the list of 1st- and 2nd-level spells, correct?  When making this 3rd-level Bard from scratch, though, can I select 2nd level spells for all 6 spells known?  As another example, say you're creating a very high level Bard from scratch, starting at level 15. The book says your Spells Known is 19, and your spell slots are 1st × 4, 2nd × 3, 3rd × 3, 4th × 3, 5th × 2, 6th × 1, 7th × 1, and 8th × 1.  So, for those 19 Spells Known, you can choose any spells from 1st through 8th spell level. Am I free then to select as many spells as I can at 8th spell level (5 in number), working backwards, and in the end ignoring the 1st, 2nd, 3rd level spells entirely?  As another example, the Ranger doesn't know any spells at 1st level, nor have any spell slots, but the book says “You know two 1st-level spells of your choice from the ranger spell list.” Does it mean at 2nd level and above?  Long story short: When choosing Spells Known for a spellcasting character created above 1st level, am I allowed to choose my Spells Known at whatever spell level I like, just so long as I have at least one spell slot of that level?  I'm working on a D&amp;D 5e character generator and need to clarify this. Why can't enum's constructor access static fields? Why can't enum's constructor access static fields and methods? This is perfectly valid with a class, but is not allowed with an enum.  What I'm trying to do is store my enum instances in a static Map. Consider this example code which allows lookup by abbreivation:  public enum Day {     Sunday("Sun"), Monday("Mon"), Tuesday("Tue"), Wednesday("Wed"), Thursday("Thu"), Friday("Fri"), Saturday("Sat");      private final String abbreviation;      private static final Map&lt;String, Day&gt; ABBREV_MAP = new HashMap&lt;String, Day&gt;();      private Day(String abbreviation) {         this.abbreviation = abbreviation;         ABBREV_MAP.put(abbreviation, this);  // Not valid     }      public String getAbbreviation() {         return abbreviation;     }      public static Day getByAbbreviation(String abbreviation) {         return ABBREV_MAP.get(abbreviation);     } }   This will not work as enum doesn't allow static references in its constructor. It however works just find if implemented as a class:  public static final Day SUNDAY = new Day("Sunday", "Sun"); private Day(String name, String abbreviation) {     this.name = name;     this.abbreviation = abbreviation;     ABBREV_MAP.put(abbreviation, this);  // Valid } What is the motivation behind axiomatically forcing the underpinning group of a ring to be abelian? Noncommutative rings are vastly more complex than commutative ones, so I am assuming that allowing the additive operation to be noncommuting would just make matters worse. Is there something deeper here, or is this a restriction for the sake of convenience and simplicity? Evaluation of the limit $\lim\limits_{n \to \infty } \frac1{\sqrt n}\left(1 + \frac1{\sqrt 2 }+\frac1{\sqrt 3 }+\cdots+\frac1{\sqrt n } \right)$ Evaluate the limit : $$\lim_{n \to \infty } {1 \over {\sqrt n }}\left( {1 + {1 \over {\sqrt 2 }} + {1 \over {\sqrt 3 }} + \cdots + {1 \over {\sqrt n }}} \right)$$  I can use the sandwich principle, certain convergence criteria, Cesaro mean theorem, limit arithmetic.. things around this area.  Any help would be greatly appreciated, thanks!  Sorry for not elaborating more at the beginning, rookie first-post mistake I suppose. :) (How) Can I use existing stapled electrical wire to fish new wire? I nicked an electrical cable while doing a plumbing repair and so need to fix it. I previously  about repairing the damage in place, but there are receptacles 6-10 feet away on either side of the damaged wire, so it may not be too difficult to just pull new wire. Most of the wire is run horizontally through the studs, which is great, but it will at least be stapled at both boxes (and possibly more). The horizontal run is ~18" up from the floor, while the receptacles are ~6". There is also an inside corner the wire is run through. Wire is 12/2.  Is it possible to use the existing wire to fish the new wire, even though the existing wire is stapled? Would I need to open up the wall to remove the staples?  I found a , but that pertains to telephone wires which sometimes use different staples than electrical wires. I initially thought that dark energy must in some way violate conservation of mass and energy since the component of the energy density of space that comes from dark energy is constant, and space is expanding. Therefore, as space expands the energy in the universe that comes from dark energy would increase. I presumed the source of this energy was not coming from the conversion of other types of energy to dark energy, so it must violate conservation.  I decided to Google this and came upon this article:    It says that dark energy does NOT violate conservation and quotes Carroll, Press, and Turner (1992):  "…the patch does negative work on its surroundings, because it has negative pressure. Assuming the patch expands adiabatically [i.e. without loss or gain of heat], one may equate this negative work to the increase of mass/energy of the patch. One thereby recovers the correct equation of state for dark energy: P = – ρ c2. So the mathematics is consistent."  Is there a way to explain this in layman's terms? (The blog attempted to do this, but it was very unclear to me.) More specifically, can you explain where my initial train of thought described above fails when I erroneously concluded that dark energy violates conservation?  Thank you. How can I render a VisualForce Page as PDF and have a button on the page that saves this PDF as an attachment to a record?  I want to have a button on my object detail page, 'Generate PDF' which will open a VisualForce Page for preview. On the Preview page I need a button to Save or Save and Email this PDF.  Edit - I use the professional edition + API enabled, so I cannot write a controller but maybe replace that with ajax toolkit?   Is that doable? I know that I can use something like cat test.txt | pr -w 80 to wrap lines to 80 characters  wide, but that puts a lot of space on the top and bottom of the printed lines and it does not work right on some systems  What's the best way to force a text file with long lines to be wrapped at a certain width?   Bonus points if you can keep it from breaking words. Since it seems to me, that a lot of people still need sidebar workarounds, I would be interested to learn about the use-cases, experienced challenges and (most important) possible strategies to avoid them by using different approaches. This is related to the methods discussed here:   In my experience there are a few extremely important and constantly repeating patterns, which to my knowledge are still very hard to be solved using more official techniques. I will also contribute my own top-N use-cases, which are mostly related to UX and UI concerns. You are very welcome to add your own scenarios as answers and add comments on how you would avoid a workaround. My dream would be to team-elaborate strong and repeatable solution-patterns for the most common use-cases.  Finally I would be interested in the experiences of all of you who participate in the Aura pilot, which hopefully could make this kind of workarounds obsolete. Pass shell variable as a /pattern/ to awk How to fix dpkg error [2]? Every time I try to install or remove a package, I get this error. I thought maybe it was the hard disk, but a disk check gave me a clean bill of health. dpkg: unrecoverable fatal error, aborting: reading files list for package 'linux-headers-3.16.0-31': Input/output error E: Sub-process /usr/bin/dpkg returned an error code (2) A package failed to install.  Trying to recover:  I tried the solution of removing the listing for this file from the dpkg status file, but to no avail. I tried purging the package but no use. I'm stuck at this point as nothing I can find on Google helps. Update: This is now what the error says: dpkg: unrecoverable fatal error, aborting: E: Sub-process /usr/bin/dpkg returned an error code (2) A package failed to install.  Trying to recover:  After trying:  Update2: Seems the drive has bad sectors, but the reallocated sector count is 0. The drive is relatively old, however, so I expect some issues. I won't be able to replace it immediately, and until then I would still like to be able to keep the system up to date (especially for security reasons). I noted that there was an issue with coping some md5 checksums related to the package mentioned in the error, but I don't know what to do with those, such as if clearing them would allow dpkg to continue. I just installed Ubuntu alongside to Windows 7, and now Windows 7 will not boot.  When the system starts, it shows me entry for Windows 7 in the boot menu, when I click on the Windows 7 option in the boot menu, after few seconds it will show me the boot menu again and Windows will not boot. It shows me no error message. Windows 7 option is available in the boot menu but it just does not boot.  Here are my boot info results   update - 30/01/2012 I tried windows recovery - fix startup issues - that showed no problems but issues were not resolved  Then I tried the widnows recovery console and run following commands  bootrec /fixboot bootrec/ fixmbr bootrec /RebuildBCD   But that does not help, Now neither ubuntu nor windows will boot. When I boot from windows CD it shows me a valid windows installation in c:\ drive.  update After a lot of help I got from #ubuntu channel and trying out different things, ultimately I can now boot both windows and ubuntu, still, the issue is not completely resolved though.  Here's what made it work  Boot using ubuntu live CD and then run the testdisk utility as steps mentioned  Restart system and I was able to see the boot menu and boot into Ubuntu, then put the following code in boot/grub/custom.cfg. Restart and now I can see one more entry to boot win7, clicking on it boots windows.  menuentry "Windows 7 (loader) with grub ntldr workaround" --class windows --class os   {     insmod part_msdos     insmod ntfs     set root='(hd0,msdos1)'     search --no-floppy --fs-uuid --set=root FAF0F57DF0F54085     ntldr /bootmgr }   It will make windows boot probably but now windows have a dependency on Ubuntu and I can not remove Ubuntu or else windows will stop working.  Credit goes to 'Jordan_U' on #ubuntu channel.   update Here are the win7 boot details I got from EasyBCD  Windows Boot Manager -------------------- identifier              {9dea862c-5cdd-4e70-acc1-f32b344d4795} device                  partition=C: path                    \bootmgr description             Windows Boot Manager locale                  en-US default                 {04fe8f95-4b17-11e1-a45c-909d3d25f938} displayorder            {04fe8f95-4b17-11e1-a45c-909d3d25f938} timeout                 30  Windows Boot Loader ------------------- identifier              {04fe8f95-4b17-11e1-a45c-909d3d25f938} device                  partition=C: path                    \Windows\system32\winload.exe description             Windows 7 Home Premium locale                  en-US osdevice                partition=C: systemroot              \Windows resumeobject            {8d25a443-4b0a-11e1-a835-806e6f6e6963}   Note Still, I am looking for how can I have everything clean and how can I boot windows without having a dependency on Ubuntu. so that if ever I have to remove ubuntu, windows will keep booting file without ubuntu. The Civilization series of games is famous for having a way to play by e-mail. This allows people to take a long time on their turn without holding up the other players, as you do in a real-time game. Yet, I can not find any method to play by e-mail in the game menus. Does it exist? If so, how do you do it? Can I install a ROM made for a different device? Expected Value of Local Maxima and Local Minima Recently I came across this question:  Given a random permutation of integers 1, 2, 3, …, n with a discrete, uniform distribution, find the expected number of local maxima. (A number is a local maxima if it is greater than the number before and after it.) For example, if n=4 and our permutation was 1, 4, 2, 3, then the # of local maxima would be 2 (both 4 and 3 are maxima). I know the answer will be (n+1)/3 .I wanted to know what will be the answer when we have to consider the local maxima as well as the local minima i.e Finding out the expected number of local maxima and local minima. I am interested in determining the ages of all 70+ my servers. I would like to create a growth graph showing when servers and databases were added to the environment either/both monthly or annually. I executed the following query using the SSMS multi-query feature with only partial success.  SELECT [name], create_date FROM sys.databases   It's partial success because the master and model databases return with a date of 'April 8, 2003' when I know that I created some of these servers during the past couple years.  I refresh databases from one server to another several times a week, which appears to be causing issues with the database create date.   Is there a simple method to determine the actual create date for both servers and databases? Is any quotient of a Euclidean domain by a prime ideal a Euclidean domain? Let $R$ be a Euclidean domain, i.e., a ring with a norm $N : R \rightarrow \mathbb N$ such that for any $a,b\in R$ with $b\not=0$, we may write $a = qb + r$ for some $q,r \in R$ with $N(r) &lt; N(b)$. Let $I$ be a prime ideal of $R$, so $R/I$ is a domain. Must $R/I$ in fact be a Euclidean domain?   I know that this is true if we replace "Euclidean domain" with "PID", and false if we replace it with "UFD", so there is no clear intuition to be gained from similar concepts. My first attempts at a proof was to borrow a construction from analysis and define a norm on $R/I$ by  $N(a + I) = \inf\{N(a+i) : i\in I\}$  but this didn't really get me anywhere.   So, this fact true? If so, how can I prove it? If not, whats a counterexample? The legacy tray (see the screenshot below) will be removed in GNOME 3.26. I want to wean myself off it before the change arrives in Ubuntu (17.10 or 18.04).    Can I disable the legacy tray in Ubuntu GNOME 17.04?