Concurrent Modification Exception Entity Handling
Iterating through a Collection, avoiding ConcurrentModificationException when removing objects in a loop
I made a bootable Windows 7 USB using UNetbootin, and when I try to boot from the bootable USB and select the Default boot menu entry, it gets stuck at the UNetbootin boot menu and it keeps repeating an Automatic boot in 10 seconds... message in an endless countdown loop. Selecting Press [Tab] to edit options and editing the options has no effect. When I go back to the boot menu, it keeps repeating the same countdown loop.   I've tried redoing the UNetbootin extraction, but I still have the same issue. Algorithm for computing Hadamard product of two rational generating functions If I have two generating functions $A(x) = \sum_na_nx^n$ and $B(x) = \sum_n b_nx^n$   then the Hadamard product is $(A \star B)(x) = \sum_{n} a_nb_nx^n$.  Now when $A$ and $B$ are both rational functions ($P(x)/Q(x)$ with polynomials $P, Q$) I've seen non-constructive proofs that $A \star B$ is also rational.  Given two rational generating functions $A$, $B$, is there an algorithm that efficiently computes $A \star B$? Or at least a constructive proof you could use to write an algorithm? Using TIPA with fontspec SciFi movie (or miniseries) of the afterlife I am trying to find the name of a direct to TV movie, possibly a 2-3 part miniseries which I believe aired on the SciFi channel in the 90s. I don't remember who starred in it, but the movie opened with an astronaut attempting reentry whose shuttle ends up exploding. He awakes in a large bubble of air in a river and after reaching the surface and swimming to shore, meets several other people, from seemingly many different times throughout history (including one alien, who died on Earth).  Over the course of the movie, we learn the world is the afterlife, where everyone goes when they die. The major plot involves launching a steamboat (built by Mark Twain, no less) to travel up a river to the mountains, where the beings responsible for bringing everyone to this world are.  Does anyone know what the title of this movie/miniseries is? Mounting a device — role of /dev, /media and /mnt, and the mount command I have several closely related questions about what happens when I insert a CD. The files on the CD /media/Ubuntu\ 11.04\ i386/, but from what I've seen /dev/cdrom is also involved.   What is the difference between /dev, /media and /mnt? Following is what I have found from internet but I still have little idea:        /dev — this folder contains device   files    /media — this is a mount point for   removable devices   /mnt — this is a temporary mount point     What is the purpose of mount? In other words, if a device has been represented by the OS as a device file under /dev, why can it not be accessed via the device file directly without mounting?   Is mount only used for storage device, not for non-storage device, such as graphical card, network card, camera, ...? Where is a device file under /dev mounted to, under /media or under /mnt? I remember I have seen both, but am curious when to mount to which? I found my CD was automatically mounted to /media/Ubuntu 11.04 i386. I guess the device file of the CD is /dev/cdrom, but I cannot confirm it by looking into /dev/cdrom and /media/Ubuntu 11.04 i386:  $ ls -l /media/Ubuntu\ 11.04\ i386/ total 3522 -r--r--r-- 1 Tim Tim     143 2011-04-27 13:04 autorun.inf ... $ ls -l /dev/cdrw lrwxrwxrwx 1 root root 3 2011-05-28 15:12 /dev/cdrw -&gt; sr0 $ ls -l /dev/cdrom lrwxrwxrwx 1 root root 3 2011-05-28 15:12 /dev/cdrom -&gt; sr0   How can I find out which device file is for my CD? How do you add a timer to a C# console application Just this - How do you add a timer to a C# console application? It would be great if you could supply some example coding. How to show that $\sum_{k=1}^n k(n+1-k)=\binom{n+2}3$? How to get the entity ID for a custom field in Apex? I am looking for a way to get the 15 character entity ID for a custom field on my Lead object in an Apex controller. I have tried this:  private String getEntityIdFor(String fieldName) {         Map&lt;String, Schema.SObjectField&gt; fieldMap = Schema.SObjectType.Lead.fields.getMap();         return fieldMap.get(fieldName).getDescribe().getId();     }    Of course, there is no getId() method, but this is the closest I got.   Thanks for any help. "No root file system defined" error while installing ubuntu I am new to linux/ ubuntu and just downloaded the v11 of ubuntu to learn linux. I faced this "No root file system is defined" error while trying to install it. This is how I was proceeding -    Downloaded ubuntu v11 from the ubuntu.com website, wrote the iso into a bootable cd, and then got into the linux installation process on restarting; everything fine till here. In one of the screen during installation, there are three choices - install alongside windows, something else etc.. Since I have windows 7 in the C drive, I selected the first option - "Install alongside another OS".      Let me interrupt here to give my existing system details - HardDisk   size: 640GB.  Number of existing partitions - 5 C drive - label   windows - 160GB - has windows 7 installed D drive - label linux -   160GB - does not have any data E drive - label backup - 100GB - has   some data F drive - label entertainment - 100GB  - has some data G   drive - label work - 90GB  - has some data All of the above are in   NTFS format.    In the screen that follows, an image is shown with 2 parts and each part is shown to have size equal to 80GB. There is a horizontal slider in the middle of these two images, with which I can resize the partitions. The right side partition is labeled Linux. There is also an option to do 'advanced partitions'. On clicking advanced partitions on the above screen, a new screen is shown in which the partitions existing in my computer are shown - but the labels are different. I see that there are two partitions with size = 160GB each (as expected), and so I assumed that the first 160GB would be my existing C drive and the second on would be the partition which I had labeled as linux (drive D). So I selected the linux partition and clicked on proceed/ install now, and then this error was shown - "No root file system defined".. and I cannot proceed after this.   Please let me know two things here:   During the screen in point number 3 above, the image with slider was shown. Which partition (drive c: or d: or anyother) is being referred to here? Which one am I actually resizing - is it the existing c: drive which has windows 7 installed already, that is getting shrunk and then ubuntu getting installed in the remaining space? What does ""No root file system defined" error mean? How do I select the proper partition and continue with the installation?    P.S.:  I had already partitioned my drives as mentioned above, and the D drive with 160GB was specifically left free for installing ubuntu. I would like to Select D drive during setup and install ubuntu here, while still keeping the already installed windows7 in C drive.  Thanks! On the one side, the USA is just one country. Logic says it should be, then, singular, just like the United Kingdom is. Example:     The USA owns this domain.   On the other side, if I however expand "the USA" to "the United States of America", I'd tend towards using plural &mdash; the noun the verb agrees with, "States," is definitely plural. Example:     The United States of America own this domain. → The USA own this domain.   What form should I prefer? What is the difference between "var=${var:-word}" and "var=${var:=word}"? When I entered the -al attribute with the  command, I got the following:  anupam@JAZZ:~/blog$ ls -al total 76 drwxrwxr-x 13 anupam anupam 4096 Aug 28 21:45 . drwxr-xr-x 34 anupam anupam 4096 Aug 28 20:52 .. drwxrwxr-x  8 anupam anupam 4096 Aug 28 12:19 app drwxr-xr-x  2 anupam anupam 4096 Aug 28 12:19 bin drwxrwxr-x  5 anupam anupam 4096 Aug 28 12:19 config -rw-rw-r--  1 anupam anupam  154 Aug 28 12:19 config.ru drwxrwxr-x  3 anupam anupam 4096 Aug 28 12:37 db -rw-rw-r--  1 anupam anupam 1339 Aug 28 12:19 Gemfile -rw-rw-r--  1 anupam anupam 2871 Aug 28 12:19 Gemfile.lock drwxrwxr-x  7 anupam anupam 4096 Aug 28 21:45 .git -rw-rw-r--  1 anupam anupam  466 Aug 28 12:19 .gitignore drwxrwxr-x  4 anupam anupam 4096 Aug 28 12:19 lib drwxrwxr-x  2 anupam anupam 4096 Aug 28 12:29 log drwxrwxr-x  2 anupam anupam 4096 Aug 28 12:19 public -rw-rw-r--  1 anupam anupam  249 Aug 28 12:19 Rakefile -rw-rw-r--  1 anupam anupam  478 Aug 28 12:19 README.rdoc drwxrwxr-x  8 anupam anupam 4096 Aug 28 12:19 test drwxrwxr-x  6 anupam anupam 4096 Aug 28 12:33 tmp drwxrwxr-x  3 anupam anupam 4096 Aug 28 12:19 vendor   What does each column mean, and what does the total 76 signify here? SVG for images in browsers with PNG fallback GUI to CLI command translator Is there any application (or sequence of commands) for this function: seeing the result of the actions, while using a GUI interface, being automatically translated into a Terminal (or similar CLI environment) on the same machine.  I saw this in action long years ago in VBA for Applications (for example the Macros in Excel). I wonder if there is same function in Linux. Why doesn't GCC optimize a*a*a*a*a*a to (a*a*a)*(a*a*a)? Why does my query run fast in Environment A, but slow in Environment B? I have a piece of SQL that seems to run really fast in Environment A, but the exact same query runs really slow in Environment B!  Environments are supposed to be the same, so what should I do and/or where should I look in order to see why the query doesn't perform the same? Properties of $\liminf$ and $\limsup$ of sum of sequences: $\limsup s_n + \liminf t_n \leq \limsup (s_n + t_n) \leq \limsup s_n + \limsup t_n$ Let $\{s_n\}$ and $\{t_n\}$ be sequences.  I've noticed this inequality in a few analysis textbooks that I have come across, so I've started to think this can't be a typo:  $\limsup\limits_{n \rightarrow \infty} s_n + \liminf\limits_{n \rightarrow \infty} t_n \leq \limsup\limits_{n \rightarrow \infty} (s_n + t_n) \leq \limsup\limits_{n \rightarrow \infty} s_n + \limsup\limits_{n \rightarrow \infty} t_n$.  I understand the right two-thirds of the equation, and can prove it.  I'm stuck on the far-left third.  I don't understand how that is true. Exporting PDF with Hyperlinked Attributes from ArcMap? I'm using ArcGIS 10.1 and would like to export a map to a pdf, preserving feature's attributes. I would like to be able to identify, for example, a point feature from the map on pdf with its underlying features (essentially hyperlink to a document or URL). I know one can export to such a pdf in ArcMap, with an advanced option of exporting features with attributes. I use Adobe Acrobat Pro v.10, and cannot seem to be able to find a way to bring these attributes up.   Is this possible? The parametric equation  $$\begin{align*} x(t) &amp;= \cos t\\ y(t) &amp;= \sin t \end{align*}$$  traces the unit circle centered at the origin ($x^2+y^2=1$).   Similarly,   $$\begin{align*} x(t) &amp;= \cosh t\\ y(t) &amp;= \sinh t \end{align*}$$  draws the right part of a regular hyperbola ($x^2-y^2=1$).  The hyperbolic trigonometric functions are very similar to the standard trigonometric function.  Do similar functions exist that trace parabolas (because it is another conic section) when set up as parametric equations like the above functions?  If so, are they also similar to the standard and hyperbolic trigonometric functions? I improved an edit... but did I actually?