longtabu X-columns break with xcolor
longtabu and color compatibility
Run a command without making me wait How do I find least cost path over a DEM based on slope magnitude and direction? What sort of algorithms can I use to find a least cost path through a DEM where it costs more to traverse a cell going downhill or uphill than it does to follow the contour of the land?  All the examples I've seen involve creating a least cost surface where the magnitude of the slope is part of the cost - but the direction isn't.    Additionally, the examples assume the cost to travel through a cell does not depend on the direction of travel. I once had the task of determining the following performance parameters from inside a running application:   Total virtual memory available Virtual memory currently used Virtual memory currently used by my process Total RAM available RAM currently used RAM currently used by my process % CPU currently used % CPU currently used by my process   The code had to run on Windows and Linux. Even though this seems to be a standard task, finding the necessary information in the manuals (WIN32 API, GNU docs) as well as on the Internet took me several days, because there's so much incomplete/incorrect/outdated information on this topic to be found out there.  In order to save others from going through the same trouble, I thought it would be a good idea to collect all the scattered information plus what I found by trial and error here in one place. Let $X_n$ be iid random variables with $P(X_n=(-1)^kk)=\dfrac{C}{k^2\log k}$ for all $k\geq 2$. Here $C$ is just a constant so that the sum of probabilities is $1$. Find constant $\mu$ such that $S_n/n\to \mu$ in probability where $S_n=\sum_{k=1}^nX_k$.   Here $E(X_n)=\infty$. I'm a bit lost after this. In general how does one find constants like this? A generic question across most board games: once a player has taken their turn (taken their finger off the piece they are playing), should they be allowed to change their mind?  Similarly, if a player forgets to take a privilege, such as an occupied building in Puerto Rico giving an extra worker, or plantation, if they remember a few moves later, should they be allowed to take the privilege?  Very few rules explicitly express how these events should be dealt with, so they are generally left up to the group. However, my group's rules will change depending on the personality of the players playing (not all members are available each time we play). I would like to make this consistent, and would appreciate feedback on how others deal with this scenario. Error -504 on appliation installation Yes. I've read all other questions regarding this problem. Like this one:  It's the same problem as this one but with more background information and an other app:   The details: My device is an Ulefone Be Touch 2 running Android 5.0.  My connection is perfect. To be sure I tried different networks, among them are 3G, 4G and wifi on ADSL, VDSL, cable and fiber. I've also used Tor and 3 different VPN providers in 3 countries on 2 continents. Let's say I ruled the network out.   A single app does not install: OpenKeychain.  Currently I have 126 apps installed. It does not install via desktop browser > play store > install button.    I have enough free space (40GB). The app is 7MB.   Re-adding Google account and clearing caches did not work.    Even a complete device wipe and re-install didn't work.     Downloaded the apk and tried manual installation, same error.   I also own a Nexus 7 (2013 wifi) and the app installs fine on that device. Why isn't .profile sourced when opening a terminal? Just installed Ubuntu 14.04.1 LTS.  According to .profile,  # ~/.profile: executed by the command interpreter for login shells.  # This file is not read by bash, if ~/.bash_profile or ~/.bash_login exists.   There is no ~/.bash_profile or ~/.bash_login.  It does not seem to source .profile when opening a terminal.   Why doesn't it source .profile when opening a terminal? Why is .profile there if it is not sourced? How do I know/control what is sourced when a new terminal is opened? When a new terminal is opened, does it do a "login"? Where is a good place to add $HOME/bin to my path? .bashrc? Will that cause a problem because .profile has the same code? What are the common phrases, words, abbreviations that are used on Stack Overflow, Server Fault, Super User, Meta Stack Overflow, and the other Stack Exchange sites? This is meant to be a very quick overview, not an in-depth tutorial. When considering whether a term ought to be included, please use this test:  New user comes in and posts on day 1. What terminology or jargon are they likely to run into (comments, support, system messages, etc.) that cannot be understood from the context without prior experience with the site (that is, clear only if known). For example: &quot;This is a dupe. Flag a diamond mod to close or migrate to SU.&quot; Huh? Can these instruction be made clear from the glossary? Is it clear for those for whom English is a second language?  Please:  Edit the existing answer Insert relevant links to more detailed information on the term/phrase/abbreviation Add only factual information Keep it very, very brief, terse, and to the point Delete your own comments once they become irrelevant (integrated into the glossary) Use the Edit Summary box to note reasons for your edit, not comments  Please avoid:  Opinion Using abbreviations, terms, and phrases inside a description Unverified information Uncommon terms, abbreviations, phrases Long descriptions Unnecessary detail - link to the relevant FAQ instead Citations or examples of usage Inside jokes that are not common on all of the trilogy () Common Internet jargon (that is, , , , etc.) unless usage here differs significantly  Recurring discussion: While the experiment to keep meta-discussion in the comments is going well (that is, deleting them once consensus is reached) it is clear that some discussions will be recurring, and we'll have to keep a record around so people new to the glossary can understand the consensus already reached. Add a new answer if you believe a new issue is likely to come up repeatedly. For instance, discussion about what terms to include, whether the glossary should be broken up to make linking easier, or formatting issues might be best discussed in new answer/comment posts. Linux command line. Move all files and directories in directory, except some files and directories I installed blender for the first time, so I have the latest version, 2.78c.  I played with it for a bit.  Then I discovered I couldn't save my work.  I uninstalled it and reinstalled it.  Rebooted.  Same problem.  After a little testing, I realized I CAN save to my NAS storage drive.  I cannot save on my C: drive.  Any project.  Any folder.  C: always fails.  If I run blender as Administrator, it will save to the C: drive.  But not as my normal userid.  So it sounds like a bug of some kind.  I am running Windows 10.  Bitdefender A/V.  I use OneDrive.  I have a 2TB drive installed.  All clean and purring nicely.  Is there a better way to install it?  Or some change I can make (other than always running as administrator)?    Sounds like a bug - but hopefully there's a proper solution.  Thanks,  Jerry How do I get:  id       Name       Value 1          A          4 1          B          8 2          C          9   to  id          Column 1          A:4, B:8 2          C:9 Using ST_Union in PostGIS I have a spatial table (polygons,polylines) in a database. These are digitized by multiple people. For example, a state is divided into multiple Grids and given to multiple people to digitize using QGIS; which is connected to a postgres database. Now, I have to merge all those polygons and polylines. I don't know how to do this via ST_Union. I Used the following snippet to merge the polygons and polylines CREATE TABLE schema_name.polygon_un2 AS SELECT upg.un_geom,npg.Column1,npg.Column2,npg.Column3,npg.Column4,npg.Column5  FROM (  SELECT st_union(the_geom) As un_geom,(   SELECT oid FROM schema_name.polygon    WHERE oid = 100748191   ) FROM schema_name.polygon WHERE oid IN (100748191,100763519)  ) upg  INNER JOIN schema_name.polygon npg ON npg.oid = upg.oid;   DELETE FROM schema_name.polygon WHERE oid IN (100748191,100763519);  I have the interesecting polygon oid in a Seperate Table, I want to do this process in an update query and that should be a dynamic plpgsql function.  Green : Grid , Other : Polygon But This snippet did not work !! The snippet which i expect is  It should create a new row for the merged polygons and polylines (eg oid - 1 and 2 merged to oid 3).  The polygons which are not merged (eg 1 and 2 should be deleted) Is it bad to defrag a ssd? Or just pointless? I've read on some websites that it's bad to defrag an ssd. But I'm reading on this website now and one person was like "You didnt do any harm its just not necessary to defrag it." I feel like that's wrong since every other website I've read says it will damage the ssd. Suppose there are two users that have commented on an answer. Both have the same user name, and I want to reply to one of them. How can I do this?  It appears that, under the current system, there is no way for me to do this. Specifically, from , I see that:     4. Matching is performed in reverse chronological order, so if five people named John are participating, @john will match the most recent John   So, consider this a request to add this feature using an -n suffix or something similar; e.g. @john-2 could be used to reply to the second John from the top.  Update Thanks to  for nice answer of @name(userid) based auto-complete suggestion which has no loophole. It involves no counting from top &amp; has no consequences when a comment is deleted. But, I think @name(userid) should be used directly in comment as all form inputs at SE are text (nothing embedded).  Now, I'm trying to finalize it based on it: The system should allow optional @name(userid) format for reply. Provided userid with this format, system should ignore name. And, in the situation of duplicate name based confusion, system should demand this format as mandatory to submit comment.  How to get userid? In case of duplicate name based confusion, system should append (userid) in hypertext to their profile. It'd work for mobile version too. On full version, for easy fill-up, a hover reply icon would be fine (like hover vote up icon). Upon clicking it, system should fill @name(userid) in comment text box.  From reply reader side: Multiple Johns could be confused even if they didn't come from notification (because nobody remembers his/her own userid). So, highlight the background of comments which are replied to them. Can mobs go through doors? I was wondering if mobs can go through doors or not. It's the difference between me just putting up a door to my house, or putting up dirt instead. Euler's equations of rigid body motion from least action principle I would like to derive Euler's equations of rigid body motion from least action principle.   Suppose we are in free space so we have no gravity so Lagrangian is equal to kinetic energy.   $$ L = T = \int_M \rho(x)(x\cdot \Omega_B)^2 d^3x $$  where $\rho$ is density, $\Omega_B$ is angular velocity bivector in reference body frame and $M$ is the rigid body.  The action principle says(if I haven't messed up something) that   $$ 0 = \frac{d}{ds}\bigg|_{s=0}\int_0^T \int_M \rho(x)[x\cdot (\Omega_B(t)+s \delta \Omega(t))]^2 d^3x $$  for every $\delta \Omega$ with zero ends i.e. $\delta \Omega(0)=\delta \Omega(T) = 0$. I should get these equations:  $$ I(\Omega_B) - \Omega \times I(\Omega_B)=0 $$  where  $$ I(\Omega) = \int_M \rho(x) (x\wedge (x\cdot \Omega)) d^3x. $$  But I can't see where I would get the time derivative of $\Omega_B$ from the action principle. Can someone tell me what I'm doing wrong? I guess there is some trouble with that $\delta \Omega$ can't be completely arbitrary. If $A^2 = I$, then $\operatorname{rank} (A+I) + \operatorname{rank} (A-I) =n$ If $A^2 = I$ where $A$ is an $n\times n$ matrix, then why is $\operatorname{rank} (A+I) + \operatorname{rank} (A-I) =n$.   I am not sure why this seems to be true. RX 590 IN Blender and Cycles Render I don't know why, but I cant render anything in CUDA and OptiX but OpenCL work fine. I cant use Cycles render because it's very laggy. I have newest  version of Blender and an RX 590 Red Dragon 8gb. Why does that happen?  How can I turn on my gpu? Why are memory statistics in top and htop different? Whenever I use top and htop commands to see memory stats, they are always different as shown in figures. Which should I trust? Algorithm to match one input file with given numbers of file