Apache's htcacheclean doesn't scale: How to tame a huge Apache disk_cache?

We have an Apache setup with a huge disk_cache (>500.000 entries, >50 GB disk space used). The cache grows by 16 GB every day.  My problem is that the cache seems to be growing nearly as fast as it's possible to remove files and directories from the cache filesystem!  The cache partition is an ext3 filesystem (100GB, "-t news") on an iSCSI storage. The Apache server (which acts as a caching proxy) is a VM. The disk_cache is configured with CacheDirLevels=2 and CacheDirLength=1, and includes variants. A typical file path is "/htcache/B/x/i_iGfmmHhxJRheg8NHcQ.header.vary/A/W/oGX3MAV3q0bWl30YmA_A.header".  When I try to call htcacheclean to tame the cache (non-daemon mode, "htcacheclean-t -p/htcache -l15G"), IOwait is going through the roof for several hours. Without any visible action. Only after hours, htcacheclean starts to delete files from the cache partition, which takes a couple more hours. (A similar problem was brought up in the Apache mailing list in 2009, without a solution: )  The high IOwait leads to problems with the stability of the web server (the bridge to the Tomcat backend server sometimes stalls).  I came up with my own prune script, which removes files and directories from random subdirectories of the cache. Only to find that the deletion rate of the script is just slightly higher than the cache growth rate. The script takes ~10 seconds to read the a subdirectory (e.g. /htcache/B/x) and frees some 5 MB of disk space. In this 10 seconds, the cache has grown by another 2 MB. As with htcacheclean, IOwait goes up to 25% when running the prune script continuously.  Any idea?   Is this a problem specific to the (rather slow) iSCSI storage? Should I choose a different file system for a huge disk_cache? ext2? ext4? Are there any kernel parameter optimizations for this kind of scenario? (I already tried the deadline scheduler and a smaller read_ahead_kb, without effect).


Question  I am installing a LEMP stack on a fresh minimal install of Ubuntu 14.04 LTS.  When I tried to install MySql   sudo apt-get install mysql-server   it returned an error with the following explanation:  mysql-server depends on mysql-server-5.5; however: Package mysql-server-5.5 is not configured yet.   How do I solve this problem?  What I have read  This question is very similar to , however, that question was (incorrectly, I believe) marked as a duplicate of . None of the answers to these two questions solved my problem.   I have also seen . This question was closed for being unreproducible. However, I can reproduce my problem every time I try to install mysql server on a fresh minimal installation of Ubuntu 14.04 (the key word being minimal).   Purpose of this question  I finally solved my problem, but I could not add an answer to any of the questions I linked to above, so I am creating a new question here so that I can answer it myself.


What is the current status of consecutive days logged in using the SE (Android) app?

I'll not have access to my PC in a few days, and since I have a 270 consecutive streak going on over at SO I was wondering the following:  Does the Android SE app qualify for consecutive access? And if so, what do I need to do to gain the consecutive access to a particular SE site?  I can see an issue with that with the app you access the whole SE platform, but not your specific sites.  I haven't been able to find any up to date FAQ, apart from meta questions of a year old, hence I'm requesting the current status.


I've already searched for it in google or stackexchange but didn't find anything. Is there anything for linux (exactly Kali Linux) for scrolling with the scroll mouse button? I mean, you know, like when in Windows I click on scrollMouseButton while on scrollView, there appears and icon and when I move my mouse pointer up, it scrolls up. When down - scrolls down.


Install Ubuntu on an external hard drive

If I install Ubuntu on an external hard drive USB 3.0 is it gonna be slow to work on and do some gaming (Metro, borderlands etc.)?


Why do fonts set to the same (pixel) number of size differ drastically in actual size when displayed on screen?

Something that has always puzzled me is the fact that when I change the font used in a program, even though in theory the font size is remains the same, the actual displayed size differs dramatically. For example, Inconsolata at 13 looks so much smaller than Source Code Pro at 13, so that I have to set it to 15 to make my eyes comfortable. In another example, Proxima Nova seems to be smaller than Helvetica Neue.  Why do I feel such a phenomenon? Is it only because different fonts have different single-character width, such that some fonts simply look more cuddled together? Or is it actually that font size doesn’t really mean a lot regarding the real size of individual characters (both height and width), and that different fonts might have radically different actual sizes even though the theoretical sizes specified are the same? If that’s the case, then font sizing looks to be a very confusing matter. Why isn’t there a more uniform way to represent the actual size a character is going to occupy on screen so that switching between fonts would be easier?


Restrict the range of a script that replaces input data to a certain range

There is this question regarding adding checkbox functionality to Google Drive: . And a great  is:     In the Google Sheets spreadsheet go to Tools -> Script Editor.   Enter the following code:   function onEdit() {   if(SpreadsheetApp.getActiveRange().getValue() == 1) {     SpreadsheetApp.getActiveRange().setValue('=CHAR(10004)');     SpreadsheetApp.getActiveRange().setBackgroundRGB(0,255, 0);   }   if(SpreadsheetApp.getActiveRange().getValue() == 0) {     SpreadsheetApp.getActiveRange().setValue('=CHAR(10060)');     SpreadsheetApp.getActiveRange().setBackgroundRGB(255, 0, 0);   } }      Enter into any cell a 1 for a tick, and a zero for a cross.    This code is great and it works beautifully, but I would like to know how to ONLY apply that to a range of cells and not to the whole spreadsheet.  By example, cells: G25 x I47


Existence of elements of order $p^k$ in a finite group

By Cauchy's theorem, if a prime number $p$ divides the order of a group $G$, then there is an element $g$ in $G$ whose order is $p$. In addition, if $|G|$ admits a prime decomposition with a factor $p^k$, then Sylow's theorem tells us that a subgroup of order $p^k$ must exist.   My question is the following. If $|G|$ admits a prime decomposition with a factor $p^k$, does this imply that an element of order $p^k$ must exist in $G$?   Update: As explained in Mindlack's answer (among others), the implication does not hold and simple counterexamples exist. In the comments, Mindlack discusses special cases where such an element exists.


I need a book on mathematical optimisation which covers as many topics from the following list as possible:   Introduction (Graphs, Paths, Network Planning, Spanning Trees, Matchings),  Matroids (Independence Systems and Matroids, Bases, Circuits and Ranks, Maximization over Independence Systems and Matroids Minimization over Bases Systems) Running Time of Algorithms (Algorithms, Encoding Length, Polynomial-time Algorithms, first Polynomial-time Computations),  Dynamic Programming (Multilevel Decision Processes, Knapsack Problem, Shortest Walks and Paths), Optimization in Networks (Flows and Cuts, Augmentation, Algorithm of Dinic),  Elements of Complexity Theory   It would also be helpful if you could tell me the prerequisite background for the same.


Open Finder window from current Terminal location?

If I am in a specific path in a Terminal window, how can I open that same window in a new Finder window?   Note: This is the opposite of .


Why don't applications update by calculating difference?

I have Ubuntu computers and an Android phone, and it's always perplexed me why the default update manager on Ubuntu and Google Play on the phone don't update existing versions of applications by calculating the difference between them and the new versions. I'm sure this is the case with other operating systems as well (which is why this question isn't in Ask Ubuntu or Android enthusiasts)  Consider, for example, the latest update (a minor release) of  (as of April 18,2012). The "What's new" section says it includes a critical bug fix. It's safe to assume a lot of code wasn't modified, and yet, when you update the app, it downloads over 6 MB, as if it's a fresh install.   Why can't the update servers calculate the difference (a la git) with installed versions and send only the difference? Can it really be that hard to do that with all versions? Wouldn't the saved bandwidth be a major motivation?  Edit 6 Dec 2016: Google just announced that they are going to use file-by-file patching for Android APK updates -


How do I read a text file of about 2 GB?

I have a .txt file whose memory is more than 2 GB. The problem is I cannot open it with Notepad, Notepad++ or any other editor programs.  Any solutions?


I would like to input items in a bibliography as follows:  Author(for example: Mike)  item 1: article  item 2: book  item 3；...  How can I do this?  Could anybody help me? Thanks in advance. There is a little difference from others. I need the following form  Milnor, J.:  [1]. Construction of universal bundles: I, Ann. Math., (2)63:272-284 (1956).  [2]. Construction of universal bundles: II, Ann. Math., (2)63: 430-436 (1956).  Milnor, J., and M. A. Kervaire:  [3]. Bernoulli numbers, homotopy groups, and a theorem of Rohlin, Proc. Intern.       Congr. Math., 1958.


Can I use the equals operator to match a case-sensitive String that contains underscore? str1.trim() == "Aavik_aArjun"   Or should I use a regex for this simple match as the equals operator is not working?


Interpretation of p-value in Mann-Whitney rank test

I am testing Mann-Whitney rank test with two vectors a and b. Vectors are almost similar so I expect a p-value near 0, but the returned p-value is near 1. What is the reason? I read  and also run the code with different parameters, but don't get anything near to what I expect.  from scipy.stats import mannwhitneyu import operator import numpy as np  a = [1000,100,10,1,10,100,1000,10000,1000,100,10,1] b = [999,100,10,1,10,100,1000,10000,1000,100,10,1]  print(mannwhitneyu(a, b))   The output of the code:  MannwhitneyuResult(statistic=73.5, pvalue=0.95291544831453867)   Edit:  Let's formalize the problem to eliminate any misunderstanding (please edit the question if something is wrong):  What I try to prove is that rank distribution of data are approximately equal,   Null hypothesis ($H_0$)= "ranked distribution of a and b are approximately equal"  Alternative hypothesis ($H_a$)= "ranked distribution of a and b are not equal"  significance level (alpha) = 0.05  p-value= 0.95  (p-value > alpha) so there is no sufficient evidence that $H_a$ is correct, but we cannot also conclude that ($H_0$) is true.   Instead if (p-value < alpha) was true, then we would have enough evidence against H0 and Ha can be accepted.  So what happened here is that I could not disprove the null hypothesis. However, it doesn't mean that null hypothesis is false. It is like an investigation to accuse MR X of being guilty:   $H_0$=" MR X guilty" $H_a$=" MR X not guilty"  We guess he is not guilty, but we don't have enough proof against him: (p-value > alpha), but that doesn't mean that ($H_0$) would not be true. If we could obtain enough evidence and state (p-value < alpha), then we disprove $H_0$ and we can conclude that Ha is true and he is not guilty.


If $f$ is $L^p$ then $f\circ \phi$ is $L^p$

Let (X, B, µ) be a measure space and M ∈ (0, ∞). Suppose that $\phi : X \to X$ is a map satisfying that $$\phi^{-1}(A) \in B$$ and $$\mu(\phi^{-1}(A)) \leq M\mu(A)$$ for all $A \in B$ Then I need to show that if f is $L^p$, then $f\circ \phi$ is in $L^p$ too for $p$ greater than or equal to 1. I already showed that $$\int_X f \circ\phi d\mu \leq M\int_X f d\mu$$ but I don't see how to conclude, I tried to split the integral into one part where $f\circ\phi \leq 1$ and the other where $f\circ\phi \geq 1$ but I'm at a dead end. Thank you. (Oh and I try not to use the pull-back measure since I haven't seen it in my lectures)


Do users know that clicking the logo on a website will take them to home page?

I had a discussion with a colleague about using "Home" link in main (top) navigation. I know that I should give more options to users, so, my question is not about I should use "Home" link or logo link (or both), is more related about users consciousness about this feature.  Is there any study made about user consciousness related to clicking logo to navigating to home page?


program lagging terribly despite using 1% of CPU and only 134m of ram, any assistance would be great

just installed blender onto my laptop, was working just fine on my ancient crippled pc yet now the whole program lags to an unusable degree, it takes five seconds to even open the file menu and the 3d navigation window is nearly unusable.   has anyone else had a similar issue and found a solution?


Remove Ubuntu 14.04 LTS from a desktop computer

I was given a computer with Ubuntu 14.04 LTS on it. I am not familiar with this system and it will not support a device that i would like to connect to the computer and use. I want to remove the Ubuntu so that i can install windows. When I put in the windows disc nothing happens so i have read that i need to remove Ubuntu first.  I have no idea at all how to do this. Can someone please give me the step by step to remove it. I greatly appreciate anyones help. I have never removed software but was so thankful to be given the computer that i have so i need to get windows on it so that I can use it. Thanks!


SQL: Understanding how FULL OUTER JOIN works

I have tables called Movie, Genre and Keyword, from which I have created a view called 'genkeyword'. The view 'genkeyword' has a lot of tuples, so it can be accessed at .  The following query calculates the frequency of genres that the movies in genkeyword have in common with Harry Potter and the frequency of keywords that the movies in genkeyword have in common with Harry Potter. It then combines the results of the two queries using a full outer join.  SELECT     * FROM     (         SELECT             title,             year,             count(distinct genre) as genre_freq         FROM             genkeyword         where             (                 genre in (                     select                         genre                     from                         genkeyword                     where                         title = 'Harry Potter and the  Deathly Hallows'                 )             )             AND title <> 'Harry Potter and the Deathly Hallows'         group by             title,             year     ) a      FULL OUTER JOIN (         select             title,             year,             count(distinct keyword) as keyword_freq         FROM             genkeyword         where             keyword in (                 select                     keyword                 from                     genkeyword                 where                     title = 'Harry Potter and  the Deathly Hallows'             )             and title <> 'Harry Potter and the Deathly Hallows'         group by             title,             year     ) b ON b.title = a.title;   The output of the above query is the following:  title               |   year    |   genre_freq   |    title    |    year    | keyword_freq  Cinderella              2015         2              Cinderella      2015        2     Enchanted               2007         1              Enchanted       2007        3  How to train your dragon  2010       2               null           null       null The Shape of Water        2017       2        The Shape of Water    2017       1          I know that for two result sets A and B, a full outer join outputs the rows that match in A and B, as well as the rows in A that don't have matching rows in B and the rows in B that don't have matching rows in A.  However, in the third row of the output (where the movie is 'How to train your dragon'), why are there null values for the title and year attribute? I know that the for the keyword_freq the value would be null because the movie does not have any keywords in common with Harry Potter, but wouldn't the title and year attributes have the values 'How to train your dragon' and 2010 respectively?  Any insights are appreciated.


Firefox: change/disable default keyboard shortcut configuration

I have installed the  add-on and configured it to toggle Offline Mode on Firefox, whenever I press Ctrl + Shift + O. It worked fine on previous versions of Firefox (before version 28.0).  However, now, when I have the Developer Tools pane open, pressing Ctrl + Shift + O causes the pane to switch to the Toolbox Options tab and consequently my 'toggle offline' option does not get triggered. (This happens only when the keyboard is 'focused' on the Developer Tools pane; if I'm actually working on a web page (i.e. some web page element is in focus), Ctrl + Shift + O always works regardless of whether the Developer Tools pane is open or not.)  I don't think a plugin or add-on would help in this regard, because the Ctrl + Shift + O shortcut assignment seems to be part of Firefox's Developer Tools pane itself. (After all, Keyconfig, via which I customized that shortcut, is also an add-on!)  As such, I'm looking for a possible way of altering the configurations of the Developer Tools toolbox (or Firefox itself, for that matter) in order to regain control of my keyboard shortcut Ctrl + Shift + O. (Well, I know it would be easier to change my shortcut to a different one, but I'm so accustomed to pressing Ctrl + Shift + O whenever required, that I cannot get rid of it now. :) ) I have been looking up the issue on the web for quite a long time, but still could not arrive at a satisfactory solution.  Any ideas/suggestions are highly appreciated.


Robby McKilliam says in a comment to  post:     It should be pointed out that, from the frequentists point of view, there is no reason that you can't incorporate the prior knowledge into the model. In this sense, the frequentist view is simpler, you only have a model and some data. There is no need to separate the prior information from the model   Also, , @jbowman says that frequentists use regularization by a cost/penalty function, while bayesians can make this a prior:     Frequentists realized that regularization was good, and use it quite commonly these days - and Bayesian priors can be easily interpreted as regularization.   So, my question is, can frequentists in general incorporate into their models what Bayesians specify as priors? Taking the regularization as an example, is the cost/penalty function really integrated into the model, or is this a purely artificial means of adjusting the solution (as well as making it unique)?


Regular expression to select whole string consisting of all characters type

I am learning about regular expressions and don't know how to write a regular expression for selecting a whole string which can consist of any character.  For example string like " Happy coding_programming with-C"


Let $l^2 = \{x = (x_n)| x_n \in \mathbb{R}, \sum_{n=1}^{\infty} x_n^2 < \infty\}$  be the Hilbert space of square summable sequences and let $e_k$ denote the $k^{th}$ co-ordinate vector (with $1$ in $k^{th}$ place, $0$ elsewhere). Which of the following subspaces is NOT dense in $l^2$?   span$\{e_1-e_2, e_2-e_3, \ldots\}$ span$\{2e_1-e_2, 2e_2-e_3, \ldots\}$ span$\{e_1-2e_2, e_2-2e_3, \ldots\}$  span$\{e_2, e_3, \ldots\}$                                                        I have knowledge in Analysis , metric spaces , Topology. Still I find this problem   unacquainted. Can anyone please tell me which portion to read to be able to answer this question?


In MySQL 'USE INDEX' is not working But 'FORCE Index' seems working fine

EXPLAIN EXTENDED   SELECT * FROM table_name  --  FORCE INDEX(dummy_date)   USE INDEX(dummy_date)  where dummy_date   between '2020-12-01' AND '2020-12-31'  AND name='something';  ALTER TABLE `table_name` ADD INDEX `dummy_date_index`(`dummy_date`)  When I execute this query then indexing is not working but if I use force index then its working with index. Please let me know the correct approach to use the index for millions of rows.


Numerical Approximation of Differential Equations with Midpoint Method

I want to proof that the local truncation error of the Midpoint Method is    $d_{k+1}=O\left(h^{3}\right)$    Approach  The local truncation error is defined as:  $d_{k+1}=u(t_{k+1})-\underset{u_{k+1}}{\underbrace{\left[u(t_{k})+\triangle t\cdot\phi\right]}}$   $u(t_{k+1})\rightarrow$  exact solution of the differential equation $u'(t)=f(u,t)$, which is being approximated $\Phi\rightarrow f\left(u(t_{k+1})+\frac{1}{2}\left(\triangle t\right)\cdot f\left(u(t_{k}),t_{k}\right),t_{k}+\frac{1}{2}\left(\triangle t\right)\right)$ incremental Function called the Midpoint Method   The first step is to write the term $u(t_{k+1})$ as its Taylor expansion: $u(t_{k+1})=u(t_{k})+\frac{1}{1!}\cdot h^{1}\cdot u^{(1)}(t_{k})+\frac{1}{2!}\cdot h^{2}\cdot u^{(2)}(t_{k})+\frac{1}{3!}\cdot h^{3}\cdot u^{(3)}(t_{k})+O\left(h^{4}\right)$  Then the second step is to write the incremental function in a fashion that the elements can cancel out with the previously introduced Taylor expansion of $u(t_{k+1})$.  I found a solution to the second step, but i do not understand how it is formed. And i would be happy if someone could explain in detail and write out the rules which  lead to it. The solution goes as follows:  $\Phi\rightarrow f\left(u(t_{k+1})+\frac{1}{2}\left(\triangle t\right)\cdot f\left(u(t_{k}),t_{k}\right),t_{k}+\frac{1}{2}\left(\triangle t\right)\right)$  What happened here?  $=f\left(u\left(t_{k}\right),t_{k}\right)+\frac{1}{2}\cdot h\cdot f_{t}\left(u\left(t_{k}\right),t_{k}\right)+\frac{1}{2}\cdot h\cdot f\left(u\left(t_{k}\right),t_{k}\right)\cdot f_{y}\left(u\left(t_{k}\right),t_{k}\right)$  $+\frac{1}{2}\cdot\left(\frac{1}{2}\cdot h\right)^{2}\cdot f_{tt}+\left(\frac{1}{2}\cdot h\right)^{2}f\cdot f_{tu}+\frac{1}{2}\left(\frac{1}{2}\cdot h\right)^{2}\cdot f^{2}f_{uu}+O\left(h^{3}\right)$  I understand that there is some kind of differentiating going on, but i cant figure it out. Can someone provide the steps involved?    Edits  I found out that total derivatives are used somehow, but i do not have written out the exact transformation steps.


split text contains spaces but keeps words inside quotations as one unit

I want to split text into list, where file name with spaces should be treated as a single item: example  s = 'cmd -a -b -c "file with spaces.mp4" -e -f'.split() print(s)   output:  ['cmd', '-a', '-b', '-c', '"file', 'with', 'spaces.mp4"', '-e', '-f']   desired output:  ['cmd', '-a', '-b', '-c', '"file with spaces.mp4"', '-e', '-f']   I tried using some for loops but it gets nasty, is there a decent way using regex or anything else which doesn't looks ugly


If I throw a fair dice  $12$ times, the expected number of $6$ is $2$  i.e $6$  is expected to happen  $2$ times when the dice is thrown $12$ times. But the probability of getting $6$ exactly $2$ times is ${12}\choose{2}$$(1/6)^{2} (5/6)^{10}$ which is less than $1$.    I am a first reader of probability. I am quite curious to know why this is happening?    you are expecting $6$ appearing two times . On the other hand you are telling that the possibility of appearing 6 ,  two times is very low. How these two fact go simultaneously? I can not understand this.  I feel that the probability of getting six, two times should have been close to $1$. Can anyone please explain me where I am going wrong?


I have a 1TB external hard drive that I recently formatted to NTFS. It was mounting on my Ubuntu 11.10 fine until just now. I didn't make any changes to affect my OS or my exhdd.  The error that I get is:  Error mounting: mount exited with exit code 13: $MFTMirr does not match $MFT (record 0). Failed to mount '/dev/sdb2': Input/output error NTFS is either inconsistent, or there is a hardware fault, or it's a SoftRAID/FakeRAID hardware. In the first case run chkdsk /f on Windows then reboot into Windows twice. The usage of the /f parameter is very important! If the device is a SoftRAID/FakeRAID then first activate it and mount a different device under the /dev/mapper/ directory, (e.g. /dev/mapper/nvidia_eahaabcc1). Please see the 'dmraid' documentation for more details.   I did read  and . But neither helped.  I tried installing ntfsfix but no such package exists anymore. I have never used this HDD on a windows machine. If I need to use an other machine to do stuff to fix this, I have access to a mac.  Any advice?   This is my sudo fdisk -l output: What in the world is GPT? I didn't do that. It used to be NTFS.  Disk /dev/sda: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000586fb     Device Boot      Start         End      Blocks   Id  System /dev/sda1   *        2148   961320312   480659082+  83  Linux /dev/sda2       961320313   976773167     7726427+   5  Extended /dev/sda5       961320314   976773167     7726427   83  Linux  WARNING: GPT (GUID Partition Table) detected on '/dev/sdb'! The util fdisk doesn't support GPT. Use GNU Parted.   Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xcfd88605     Device Boot      Start         End      Blocks   Id  System /dev/sdb1               1  1953525167   976762583+  ee  GPT


The commutator of two elements $a, b \in G$ is defined as $[a, b] = aba^{−1}b^{−1}$.   Let $[G, G] =\langle [a, b] | a, b \in G\rangle $ be the generated subgroup of all commutators of the elements of $G$.   Let $H\triangleleft G$.   Prove that  $G/H$ is abelian iff $ [G, G] \subseteq H$.  I have previously proved $[G,G] \triangleleft G$ and $G/[G,G]$ is abelian The following solution is provided, but there are some things I don't understand. I feel need the intermediate steps  they are not provinding to fully understand it. Can someone shed some light? Solution: If $G/H$ is abelian for every $a, b \in G$ it follows that $abH = baH$,that is $aba^{−1}b^{−1} \in H$.  (1)  How do they get this?  so for every  $a, b \in G$ we have $[a, b] = aba^{−1}b^{−1} \in H$,  but now the subgroup $[G, G]$ generated by the elements of the form $[a, b]$ is contained in $H$.  (2) They proved one commutator is in $H$, how does it extent to the whole generated subgroup?  Viceversa, if $ [G, G]  \subseteq H$ then for every $a, b \in G$ we have $(abH)(a^{−1}b^{−1}H) = H = 1_{G/H}$;  (3) I would write $(abH)(a^{−1}b^{−1}H) =[a,b]H$, why does this equals H?  So $abH = (a^{−1}b^{−1}H)^{−1} = baH$.


Why is there a peeking duck in my profile pic?

In , you may see something odd: a peeking duck.    I've just recently uploaded this new profile picture of mine. I checked it after the upload and everything's fine. After a few hours, I opened my profile and there it is, the duck has somehow become afraid of the people viewing it.  Is this a bug, a feature, or is it just the duck?  I am about to re-upload my profile pic, but I've decided to drop first this topic to meta.  And if you're curious,  is the original picture.    ADDITIONAL: I've used the non-gravatar way to upload the picture.  ADDITIONAL 2: The problem only shows in the profile view. No problem in chat, less info profile view, and in the questions and answers.  UPDATE: Re-uploaded picture. Status normal (for now, at least).


Why is this preg_match letting almost anything through?

I'm trying to use preg_match to test an URL.  here's a part of my code:  $url_array[0] = $_REQUEST['url0']; $url_array[1] = $_REQUEST['url1']; $url_array[2] = $_REQUEST['url2']; $url_array[3] = $_REQUEST['url3']; $url_array[4] = $_REQUEST['url4'];  foreach ($url_array as &$val) {     if(substr($val, 0, 7) != "http://" && substr($val, 0, 8) != "https://" && substr($val, 0, 4) != "www." && $val != "") {         $val = "http://".$val;     } }  foreach ($url_array as &$val) {     if(!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i", $val) && $val != "") {     header("Location: {$_SERVER["PHP_SELF"]}?p=home&x=urlerror");     exit;     } }   The problem is it lets through random stuff like http://i'll just use whatever ;G characters here and it'll be fine as an URL. Why is this?  Thanks! -G  FINAL CONCLUSION:  Regex for URL sorta sucks, I exchanged it for this:  foreach ($url_array as &$val) {     if(!filter_var($val, FILTER_VALIDATE_URL) === true && $val != "") {         header("Location: {$_SERVER["PHP_SELF"]}?p=home&x=urlerror");         exit;     } }   And it seems to work perfectly. :)  Thanks to @Passerby and @Chris85


Does .html extension in URL help for SEO?

I am working on dotNET and I have changed URL extension from .aspx to .html. Is it good to use .html extension ? My actual URL is www.example.com/Project.aspx?Id=2&Type=this-is-something I have replace this as www.example.com/Projects/2/this-is-something Is it fine ? Else give me suggestion which URL should I use for SEO. I can make URL anyhow I want using URL Rewriting. I want to make it best URL for SEO. Please help me regarding this.


If an astronaut had stationed in International Space Station for the duration of mission, 17 years, would he be older?

Today the NASA International Space Station started the 100000 orbit after 17 years in the space. I just wonder if there were a team of astronauts which were in the Lab for all the duration of last 17 years, how much older they would be due to the combination of Einstein's especial theory of relativity and general theory of relativity?   Here is the link to NASA's youtube video.


What's the difference between a method and a function?

Can someone provide a simple explanation of methods vs. functions in OOP context?


\cline with \usepackage[czech]{babel} doesn't work

I'd like to use \cline command in my table, but it doesn't work when I use it together with \usepackage[czech]{babel}. What I should do? Thanks.  Here is my example code:  \documentclass[10pt,a4paper]{article} \usepackage[left=2cm,right=2cm,top=2cm,bottom=2cm]{geometry} \usepackage[cp1250]{inputenc} \usepackage[czech]{babel} \usepackage[T1]{fontenc}  \begin{document}  \begin{tabular}{|c|cc|c|} \hline  11 & 12 & 13 & 14 \\ \cline{2-3} 21 & 22 & 23 & 24 \\ 31 & 32 & 33 & 34 \\ \cline{2-3} 41 & 42 & 43 & 44 \\  \hline  \end{tabular}  \end{document}


When I choose the Connection Type in VPN Connections, I have only PPTP and I can't find OpenVPN, but I already installed it via terminal with the command sudo apt-get install openvpn easy-rsa  Why I can't find it?


Is $(-\infty,3]\cap(0,1)^c\cap[-1,\infty)$ closed? Open? What are interior points?

$$\text{Let }\;\;A_1 = (-\infty, 3]\cap (0, 1)^c \cap [-1, \infty), \quad A_2 = \left\{(-1)^n \frac {\sqrt 2\,n}{n+1}: n = 1, 2, \ldots\right\}$$      Is $A_1$ open? Is $A_1$ closed? Find interior points of $A_1$. Find limit points of $A_2$.   1) I think first answer is not opened and closed, and I'm not sure how to find interior points.  2) $A_2$ converges to $\sqrt2$, so can you say $\sqrt2$ is the limit point of $A_2$? What is the difference between "limit point" and "limit"? And how to find limit points of $A_2$?


How to calculate limit of a recursive without starting point?

I want to find limit of the sequence $x_{n+1}=x_n(2-ax_n)$ but I don't have the start point. Is it possible to find it's limit when $n\to \infty$?


Why is it "your Majesty", but "my Lord"?


How do services that make subsites (ie. new subdomains) get those sites indexed by Google and other search enginex?

Services like tumblr, github pages, quora blogs, etc. make new subdomains when a user signs up or makes a site.  So the subdomains are like: blogname.tumblr.com , pagename.github.io, blogname.quora.com, etc.  How do google and other search engines find out about these new sites?  Is it as simple as having a sitemap.xml file being "resubmitted" to google?  See . I know that you can resubmit sitemaps to google via an HTTP request, but what about for new sites without a previously submitted sitemap?  Or do the owners of the subdomain (the user who set up the new site) have to submit their site manually via  ?  Just getting started learning about SEO and how google crawls the web. Couldn't find anything that answer this (or I'm just bad at Google), hoping someone can answer. Thanks!  Edit: I read through this:  But the question still holds for sites where subdomains are generated dynamically.


Measuring length of two wires inside copper with a TDR

I have a cable as in the drawing. The black parts are insulators and the brown parts are copper, so there is a big copper cable and inside are two smaller copper cables. When the big copper cable is tied to ground I can use a time domain reflectometer (TDR) on the smaller cables to determine the length of the cable. What happens if the big copper cable is in use with a current running through it that is 1000 times bigger than the current running through the two smaller copper cables? Will I still be able to determine the length with a TDR? I think there shouldn't be a capacitance between the two smaller copper cables - but how am I then able to measure with it a TDR?


I installed a custom module that created few content type that I'm no longer need it. I disable and uninstall that module but I still have the content type. And it bother me every time I see it. So I try to delete it however, I cant because for some reason doesnt have the delete button. So now I have 5 content type that I don't need. Can anyone have a solution on how to remove these content types ?  In this picture you will see that doesnt allow me to delete the content type.


Differences between the variations in Noether's theorem and Hamilton's Principle

Noether’s theorem can be defined for the invariance of the action under variations of paths induced by a coordinate transformation which depends continuously on a parameter, $\epsilon$, $q_i(t) \rightarrow \bar{q}_i(t, ε)$, $\bar{q}_i(t, 0) = q_i(t)$.  What differences are there between the variations, $δ_{q_i}$, considered in Hamilton’s principle, and the variations considered in Noether’s theorem?


How can I prove that $$\|f\|_{L^r}\leq \|f\|_{L^p}^\alpha \|f\|_{L^q}^{1-\alpha }$$ if $\alpha \in[0,1]$, $\frac{1}{r}=\frac{\alpha }{p}+\frac{1-\alpha }{q}$ and $f\in L^p\cap L^q$. It looks to be something with Holder, but I can' conclude.


Why don't the people in The Walking Dead use more disguises?

So, it is established that using the bodily fluids of a zombie hides you from zombies. The characters know this. (They also may know that keeping semi-disabled zombies also works).  Why don't they just keep the innards around to keep themselves safe?


Regarding the "Error Downloading: insufficient space" error in the Google Play store

I've spent a long, long time searching for a viable, long-term fix for this problem; though I'm beginning to believe that Google Play (or Google Play Services) is to blame. I recently factory reset my phone running KitKat 4.4.2, which has both 16GB of Internal Storage (not an internal SD Card) and a 16GB external microSD card. Even with over 12GB of space remaining (after the factory reset, I was free to download apps from the store with no errors for a while, though it was visibly running a different version), it gives me this error. This is 12GB of Internal Storage, I have over 7GB more on the SD card.  I'm currently at a loss about this. I've attempted to rollback both the Store and the Services apps, and it only clears me to download apps for 5-10 minutes (if that) before giving me the same old error. “Error while downloading There is insufficient space on the device”.  Update: While writing this question up, yet again I attempted to download three apps. The first proceeded through the process without any issue (keep in mind that I had not changed anything since the last time an error was encountered - I simply unlocked the phone and clicked install on the already-open Play Store page for Facebook Messenger), while the second and third spat out the same old error.  I have attempted to clear my cache/move it to another partition, clear the data on both the Store and Services apps as well as the caches, and several other things. APK files never fail to install when attempting to install from an external source. This issue is also not local to this phone alone, my previous model did the exact same thing without the allowance for one download that I just experienced.  Edit regarding "duplicate question": Whether this is a duplicate question or not, I have found no valid solution for this, regardless of how many threads I have looked at and how many different methods I have tried. I've purchased a new cellphone to try and bypass this error ffs. It is not my home internet, as I have attempted to update apps and download new apps from both my mobile internet connection and from several (more than five) different internet sources; inclusive of a USB-tethered internet connection shared from both my computer and a friend's computer. I would like to state that this question is different in the light that I have tried and exhausted every method I have come across, without a single ounce of lasting success.  To put it bluntly, I think that Google needs to get off their asses and fix the problems that so many people are so blatantly reporting.


Are there other kinds of bump functions than $e^\frac1{x^2-1}$?

I've only seen the bump function $e^\frac1{x^2-1}$ so far.  Where could I find examples of functions $C^∞$ on $\mathbb{R}$ that are zero everywhere except on $(-1,1)$?  Are there others that do not involve the exponential function?  Are there any with a closed form integral?  Is there a preferred function?


Can we deduce $f^p\in W^{1,1}(U)$ if $f\in W^{1,p}(U)$

Assume $U$ is some open set in $\Bbb{R}^n$. Let $f\in W^{1,p}(U)$ then we know $f^p \in L^1(U)$ ,can we further deduce $D(f^p) \in L^{1}(U)$ that is $f^p \in W^{1,1}(U)$? This may refer to the chian rule but $t\mapsto t^p$ does not has bounded derivative.If chain rule holds then easy to see $D(f^p) \in L^1(U)$ by Holder inequality I have found the solution


Packages are removed when I use "apt-get install" with a hyphen after the package name

In an attempt to install cuda, I copy-pasted some apt-get install packages. For unknown reasons the line that I got run in the end is the following:  sudo apt-get install libgtk2.0-   The result was that many packages got removed. Randomly picking a few:  libreoffice-* python-* xfce4-*    The list is huge. A considerable number of system parts have been uninstalled. Now this seems like a serious deviation from what I expect when I run apt-get install.  What is going on?


Comparing a date between two date ranges i.e,.fromDate and toDate in java

How to check whether a given date is between two dates but it should not check with the time in given date.  I have tried with after but it checks for time range too.  Could anyone help me to know about this ?  TIA.,


Is there a website that lists the cheapest flights to meet between two cities?

My significant other and I currently live on opposite coasts of the United States. We'd like to meet somewhere for the holidays, but we don't really care where; it can be a small town in the middle of nowhere; we like the idea of it being somewhat random :-)  Initially we saw that  listed flights by ascending price (without having to enter a destination city), so we were going to meet at the first coinciding airport after searching from each of our origin cities. However, we eventually realized that smaller and less popular destinations were all bunched up at the bottom of the list (among the last pages), requiring us to click "Get prices" in order to get prices—so they were not included in the sort.  Does anyone have any recommendations (websites or alternative ideas) for accomplishing what we're trying to do? Thanks in advance!  P.S. We do have strict constraints for the dates of travel; so the website doesn't necessarily have to give us any "grid" or other views for flexible dates. We're interested in flexible locations only.


Commands that may take a variable number of arguments

I have a situation where I want to define a command that takes a variable number of arguments, where the number of arguments is known programmatically via a \count, and process the parameters in some way (say as if they are a list).  As an example, say I'd like to output the parameters as a comma-separated list.  \newcommand{\makecsv}[N]{#1, #2, ..., #N}   The code that I've come up with to do this kind of operation (in a generic-ish way) essentially takes a command, \csv and expands it recursively N times. \csv needs to know how to continue the recursion, and has some state that I'd like to thread through the recursion (rather than using \global).  \documentclass{report} \usepackage{etoolbox}  \makeatletter \newcommand{\ifzero}[3]{%   % #1: count   % #2: state for #3   % #3: macro to expand to   % - should take at least 2 parameters   % - ##1: count threaded through   % - ##2: macro state threaded through   \ifnum\c > 0     \def\tmp@f##1##2##3{##1{##2}{##3}}%     \advance#1 -1%   \else     \def\tmp@f##1##2##3{)}% note closeparen here (could be param)   \fi   \tmp@f{#3}{#1}{#2}% } \makeatother  \newcommand{\csv}[3]{   % #1: count   % #2: separator state   % #3: string to concat   %    #2#3\ifzero{#1}{, }{\csv}% }  \newcommand{\makecsv}[1]{%   \ifzero{#1}{}{\csv}% }  \makeatletter \newcommand{\decl}[3]{%   % #1: decl id   % #2: decl symbol   % #3: # params   \csgdef{decl@#1}{#2}%   \global\expandafter\newcount\csname decl@#1@nparams\endcsname%   \csuse{decl@#1@nparams} #3\relax% }  \newcommand{\usedecl}[1]{%   \newcount\c   \c \the\csuse{decl@#1@nparams}   \csuse{decl@#1}(\makecsv{\c}% } \makeatother  % declare some interface routines \decl{foo}{FOO}{3} \decl{bar}{BAR}{4}  \begin{document} \usedecl{foo}{p1}{p2}{p3}\par \usedecl{bar}{p1}{p2}{p3}{p4}\par \end{document}   Is this a reasonable thing to do in 2e, or is there some sort of standard approach to this that is normally used?  Edit 1  It seems like my original MWE wasn't adequate to describe why someone might want this. I've updated the MWE with a use case. \decl allows authors to declaratively define a C-style function, and \usedecl allows the author to generate a use of the function, with its parameters bound to specific arguments.  This is similar enough to what I'm doing that it should help motivate the example.


Can LyX automatically save the PDF output in the same folder?

I use LyX 2.0.4 (on Mac OS 10.7) and would like it to do the following:   whenever I hit "View" it should automatically save the pdf output of the lyx file in the same folder the lyx file resides. Whenever I hit "View" again it should overwrite the older version of the pdf. Is that possible?  This is similar to the behavior I know from TeXShop.


Coloring cells correctly when using tabu, multicolumn, and multirow

I have made the following table header using tabu, however as you can see there is a white line separating the two merged cells of the \multirow. Does anyone have any advice on how to fix this?  Code used to produce the above table: \begin{table}[h!]   \centering   \captionabove{Overall bond energies for different base pairs}   \begin{tabu} to 0.95\textwidth { | X[c] | X[c] | X[c] | X[c] | X[c] | X[c] | X[c] | }     \hline     \taburowcolors 1{lightgray .. lightgray}                                 & \multicolumn{3}{c|}{$R_e$ [\AA]} & \multicolumn{3}{c|}{$\Delta E$ [eV]} \\ \tabucline{2-} \rowcolor{lightgray}     \multirow{-2}{*}{Structure} & this work & reference & difference & this work & reference & difference \\ \hline   \end{tabu} \end{table}


Inviting chat users to participate in external surveys

A user . Posting surveys as questions is not ok on SE sites for pretty obvious reasons. But what’s the official policy for chat rooms?


Code to display random ordered posts in Categories across pages

I need to display in random order posts in multiple categories that have multiple pages. Example - 100 posts in an Automotive category with only 20 posts displayed per category page - the order is random but does not duplicate across pages.  Right now I have this code below but it is not working - it keeps randomizing on each page which causes people to see duplicate posts.   It would be better if we could have a way to tell it to reorder - much like Turboseek or Powerseek  add_filter( 'posts_orderby', 'randomise_with_pagination' ); function randomise_with_pagination( $orderby ) {     if( is_category( 'art, asseen, auto, baby, business, cstore, candles,  cell-phones, closeouts, clothing, collectibles, cosmetics, crafts,  customer-returns, dollar-store, dvd-video, electronics, fashion-accessories,  flags, food-grocery, furniture, general-merchandise, gifts, handbags,  health-beauty, holiday-seasonal, housewares, incense, jewelry, knives, lawn- garden, leather, licensed, logistics, made-in-usa, military, music,  novelties, party-greeting-cards, patriotic-items, perfumes, pet-supplies,  professional-supplies, promotional items, religious, security defense,  shoes, smoking-products, socks-hosiery, sporting-goods, store-supplies,  sunglasses, tools-hardware, toys-games, trade-shows, uncategorized, vaping,  watches' )  ) {         // Reset seed on load of initial archive page         if( ! get_query_var( 'paged' ) || get_query_var( 'paged' ) == 0 ||  get_query_var( 'paged' ) == 1 ) {             if( isset( $_SESSION['seed'] ) ) {                 unset( $_SESSION['seed'] );             }         }          // Get seed from session variable if it exists         $seed = false;         if( isset( $_SESSION['seed'] ) ) {             $seed = $_SESSION['seed'];         }               // Set new seed if none exists             if ( ! $seed ) {                 $seed = rand();                 $_SESSION['seed'] = $seed;              }               // Update ORDER BY clause to use seed              $orderby = 'RAND(' . $seed . ')';      }      return $orderby;  }   My question was identified as already answered but it is different because the code is not working across pages - I must have done something wrong.


When in Edit Mode, I find sometimes I want to move an edge, or at least two vertices, in a direction that would be perpendicular to their orientation along their existing edge.  At that moment, the Transformation Orientation selections (Normal, Local, Global, et al) have no vectors pointing in that direction.  How might I, or is it possible to, change the "polarity" of those manipulator vectors (independent of the given selections: Global, Local, Normal, Gimble, View) so that one of them is pointing in the perpendicular direction to the line/edge between the vertices?


How do I connect to my Bluetooth headset?

I have an ACER C7 Chromebook with Ubuntu 12.04 installed.  Also I have two apps installed Bluetooth Manager and Bluetooth.    I am trying to connect an  to Ubuntu. I have tried to set up the new device and pair, but the headset is never recognized.  I checked hard and soft setting for Bluetooth and they are on.  I am new to Ubuntu 12.04 and Linux and need specific instructions.


Using FILTER or IMPORTRANGE to bring in and filter data from another spreadsheet

I want to bring in data from a separate sheet and filter it.  I can get IMPORTRANGE to work like this:  =IMPORTRANGE("URL","A:J)   But that doesn't filter. I can only get FILTER to work in the same sheet like this:  =FILTER(Sheet1!A:J, C:C="Yes")   Is there anyway to bring these two functions together and FILTER data from another spreadsheet into a new sheet, based on column C info?  The reason for doing this is to then use the auto notification setting, so whenever someone enters "yes" into the sheet I can be notified.


Small rip in one of the internal pages in Indian passport

I live in the US and need to travel to India next month. I just realized one of the internal pages is ripped. Does that mean I cannot travel ?   Passport processing is taking upto 8 weeks and tatkal is not possible unless you have an emergency. Please advice


Does every object of virtual class have a pointer to vtable?  Or only the object of base class with virtual function has it?  Where did the vtable stored? code section or data section of process?


Pokemon GO missing google sign up option

Recently I downloaded Pokemon GO but when I try to sign up with google account,the option isn't there. Help please. I use a LG G2 mini


Add a 3mm margin to every side of an A4 document

I have created a document in LaTeX and the document is complete, but the printers have asked for a 3mm white board applied to the PDF, so the overall size is 6mm wider and taller than standard A4.  How would I do this?  I found a similar question but this is for A5 paper instead:   \documentclass[a4paper, twoside, 12pt, hidelinks, final]{article}  \usepackage[top=1in, bottom=1in, left=0.75in, right=0.75in, headheight=35.4pt, footskip=35.4pt]{geometry}  \begin{document}  \clearpage\mbox{}\clearpage  \end{document}```


Adding OpenWeatherMap WMS layer using PyQGIS?

I would like to add in QGIS real time weather data.  I found this  and this  and I tried to follow the example, but without any success.  I've added a WMS weather data layer for precipitation to the QGIS map, as follows:  First, the parameters for the service:  service = 'crs=EPSG:900913&dpiMode=7&featureCount=10&format=image/png&layers=precipitation&styles=&url=http://wms.openweathermap.org/service'   Next, create the raster layer, specifying WMS as the type:  rlayer = QgsRasterLayer(service, "precip", "wms")   Finally, add the precipitation layer to the map:  QgsMapLayerRegistry.instance().addMapLayers([rlayer])   the example didn't show any error in the code and no data was added to the weather layer either, I'm not sure why?


Is it better to use USB A or USB B or RS232 to communicate over long distances?

As per the previous post (which was 5 years ago), I have a  that has three forms of serial communication. One is an RS232, the other is USB A and finally a USB B. So I have three options to connect my PC to this device. The device sends the scanned RFID tags through this serial connection to my PC. I want to place the reader 60 meters away from my PC. Which type of serial communication should I use?


What camera do you offer to a beginner for his first dslr or dslr like

I'm new on photography, actually not new yet. I'm confused on which camera to choose for my first. There is up to 400$ in my packet for my first camera. I've searched alot and found two main dslr like cameras; Canon Sx50 hs and Sony HX300.   But then, I read some posts about high noise on higher iso levels on dslr like cameras such these two. Then I tried to find an entry level dslr camera but couldn't find, because I don't know about cameras. Could you please help me on this?


Is there a word that defines describing something in the past with modern language?

For example, Jane Austen's carriage went up and down the hills like a roller coaster.


After editing .bashrc, Ubuntu doesn't seem to be able to find some libraries/packages anymore. Any idea why?

Student coder here. I am trying to complete a project that asks me to install  a package called "libncurses5-dev" and run a program through Ubuntu.  It worked the first day, thankfully. However, on the second day I wanted  to set my default directory to my homework folder so that I could skip the  cd /mnt/c/Users/... step and just go straight to where my programs are. I  tried to follow a tutorial online but I believe I made a typo or something  because afterwards my Ubuntu kept crashing! I could not open it for long  enough to fix it, the error was something along the lines of "directory does  not exist." So, I uninstalled and reinstalled Ubuntu. I redid the process of  installing all the packages I needed for coding on WSL. However, when I need  to run my program, it keeps saying that I am missing a package. When I try  to install that package, it says the package does not exist. Please see the  attached files, which show what the project is supposed to look like and  what it looks like now. I looked at image 2 again and it shows that I made a typo in the library name, but after trying it again I get the same error  anyways. Thanks in advance for the help.


Can anyone tell me how I can turn RAID off on a DL380-G5.  I just want the disks connected directly without any RAID as I want to use this to test Microsoft's software RAID.  Can't seem to find anything in the BIOS to do this.


Displaying user's default image with User Picture Field module

I am installing the User Picture Field module to take over the Drupal default user picture but it does not display the default user image when empty (D7, Bartik.)  What snippet should I add to the page--user--edit.tpl.php template so that the uploaded user picture is displayed OR the default "nophoto.jpg" file when the user has NOT uploaded a picture.  I can do the first part and display the uploaded picture but I can't get the "nophoto.jpg" to display. The "nophoto.jpg" is located in public://pictures/nophoto.jpg and I do not use image styles.  Any and all help is appreciated.  Thank you :)


Changing data source of layers with ArcPy?

How do I change the data source of all layers in a map document using ArcPy and Python?


What is the standard measurements of a cricket ground?

What is the standard measurements such as straight distance , on-off distance, radius of the ground etc of a cricket ground ?


How can I get a text superscript of the hash (#) symbol in Latex to work? I tried \textsuperscript{\#} to no avail.   I should have been more specific in my question. I am using \usepackage{fontspec} and \usepackage{xltxtra}, with \setmainfont{Calibri}. While Latex/Xelatex prints the #, it does not print it as superscript. When I use fonts Arial, Computer Modern, or Palatino, Latex correctly prints the # as superscript.   \documentclass[10pt, a4paper]{article} \usepackage{fontspec} \usepackage{xltxtra} \usepackage{microtype}  \defaultfontfeatures{Mapping=tex-text,Ligatures=TeX} \setmainfont{Calibri} \begin{document} \textsuperscript{\#}example \end{document}


Problem after starting the game, nothing happens when I click Bulbasaur, Squirtle, or Charmander

I started Pokemon Go yesterday and have had the same problem since. The professor gives me pokeballs and then screen appears of my avatar and 3 Pokemon (Bulbasaur, Charamander, Squirtle). But when I click any of the Pokemon nothing happens. Any suggestion?


Is there a way to tell apt about a manually installed program?

Here's my basic issue:  £ apt show cmake | grep -i version Version: 3.5.1-1ubuntu3 £ apt show debhelper | grep -i breaks Breaks: cmake (<< 3.9~), dh-systemd (<< 1.38), meson (<< 0.40.0~) £ cmake --version cmake version 3.11.20180516-gacb971 £   cmake was built and installed from source.  I can't uninstall the apt version because many packages depend on it.  The debhelper package is from a neovim ppa (16.04), and is honestly probably broken for 16.04 (breaking cmake<3.9 on a 16.04 system doesn't make sense), but...it's actually not an issue on my system.  But of course apt refuses to install it.  Is there a way to tell apt what my cmake version actually is?  Of course, cmake 3.11 is not an apt package and could be missing things, so I doubt it.  If not, what might be a good solution to this problem?


So I am doing a search GUI for full pc systems. The button Get Info is the action button that retrieves the values from the MySQL database and puts them in the jTextfields, but when I press on Get Info, nothing happends, and no errors.  This is the method that gets all the info, and the method is located in class DBAccess which contains all the SQL methods + the connection to database.    public SQLException getpc(fullpc fp) {         ResultSet rs;         connect ();         try {             rs = stmt.executeQuery("SELECT * FROM fullsystems WHERE Name = " + fp.name);             while(rs.next()) {                 fp.id = rs.getString("ID");                 fp.name = rs.getString("Name");                 fp.cpu = rs.getString("Processor");                 fp.gpu = rs.getString("Graphics");                 fp.ram = rs.getString("Memory");                 fp.p = rs.getString("Price");                 fp.quant = rs.getString("Available quantity");             }         }         catch (SQLException e) {             return e;         }         return null;     }     And this is the class that contains all the attributes of the table:    package area51project; public class fullpc {     public String id;     public String name;     public String cpu;     public String gpu;     public String ram;     public String mem;     public String p;     public String quant; }     And at last, the code that is put into the Get Info button:    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                                   fullpc fp = new fullpc();         DBAccess db = new DBAccess();         fp.name = (String) jComboBox1.getSelectedItem();         db.getpc(fp);         cpu.setText(fp.cpu);         ram.setText(fp.ram);         storage.setText(fp.mem);         gpu.setText(fp.gpu);         price.setText(fp.p);         quantity.setText(fp.quant);               }      The jCombobox1 is just the combobox that is near the Get Info button, so I choose the name of the PC, and then pressing the button shows the info of that PC in the jTextfields. However, Price and Quantity are shown in jLabels.  Help?


I implemented the Strauss model with the metalness, transparency and smoothness parameters, taking the formulas from the book "Programming vertex geometry and pixel shaders", this is how I implemented it:    float fresnel(float x) {     float Kf= 1.12;     float result= 1.0/pow(x-Kf,2.0) - 1.0/(Kf*Kf);     result/= 1.0/pow(1.0-Kf,2.0) - 1.0/(Kf*Kf);     return result; }  float shadow(float x) {     float Ks= 1.01;     float result= 1.0/pow(1.0-Ks,2.0) - 1.0/pow(x-Ks,2.0);     result/= 1.0/pow(1.0-Ks,2.0) - 1.0/(Ks*Ks);     return result; }  vec4 Strauss(vec3 L, vec3 N, vec3 V, float smoothness, float metalness, float transparency)  {     vec3 H= reflect(L,N);     float HdotV= max(dot(H,V),0.0);     float NdotL= max(dot(N,L),0.0);     float NdotV= max(dot(N,V),0.0);     float k=0.1;      // Diffuse component     vec3 diffuse= NdotL * (1.0 - metalness * smoothness) * (1.0 - pow(smoothness,3.0)) * (1.0 - transparency) * vec3(materialDiffuse);      // Specular component     float r= (1.0-transparency) - (1.0 - pow(smoothness,3.0)) * (1.0 - transparency);     float j= fresnel(NdotL) * shadow(NdotL) * shadow(NdotV);     float reflect= min(1.0,r+j * (r+k));     vec3 C1= vec3(1.0,1.0,1.0);     vec3 Cs= C1 + metalness * (1.0 - fresnel(NdotL)) * (vec3(materialSpecular) - C1);     vec3 specular= pow(-HdotV, 3.0/(1.0-smoothness)) * reflect * Cs;      return max(lightDiffuse * vec4(diffuse,1.0) ,0.0) + max(lightSpecular * vec4(specular,1.0), 0.0); }   The parameters metalness, smoothness and transparency are uniforms. I try to vary them, but I cannot get something similar to this result:      This is what I get with roughness 0.9, transparency 0.1 and metalness 0.1 :      It is practically equal to a lambert shader! I tried a lot of parameters combination, but I never get a shiny teapot like it should be. I also debugged the shader, and it seems like the specular component is zero in many parts of the teapot. I tried to add an if that makes look red all the areas where the specular component is zero, that's the result:      I checked many times the formulas and the implementation, and it seems like I've done all correctly. What's the problem?


How do I transfer files from PC to Xbox?

I only play Minecraft on Xbox, but I am trying to upload maps from my PC to the Xbox. I keep getting stuck as the PC does not recognise the download files as Minecraft is not installed on the PC. Horizon does not recognise the file formats in the downloaded files stored on the PC.


IDE: Microsoft SQL Server Management Studio  Mistakenly I have cleaned a table data using  delete from table tblBookData   and now it has cleaned that table, please tell me is there any way to get back that data?   If yes than please tell me the process, as I have studied there is a way to get back data if we have not closed the session.


How to make JCheckbox array of dynamic length?

I am trying to build an application for which i need to display number of check boxes that depends on the number of input.  For example: If user inputs 100, so i will create 100 check boxes.  Currently in example i am trying to make an array of JCheckboxes of fixed length. But it is giving Null Pointer Exception.  I need to store the value of check boxes because i will perform action accordingly whether a particular check box is selected or not after the user click Button.     JCheckBox [] chk=new JCheckBox[10];          for(int i=0;i<10;i++)          {              gbc.fill=GridBagConstraints.HORIZONTAL;              gbc.gridx=0;              gbc.gridy=i+1;              JCheckBox xp=chk[i];              jp.add(xp,gbc);          }     Exception in thread "main" java.lang.NullPointerException     at java.awt.Container.addImpl(Unknown Source)     at java.awt.Container.add(Unknown Source)     at UI.<init>(UI.java:93)


If so, is the empty function  from it to any other space  considered a continuous function? I can't really convince myself either way.


My question is, how can I prove that $\sin(5x)$ is not uniformly continuous?


How to skip lines in lstlisting with dots?

I am wondering if package listings has a feature that can skip a few lines and substitute them with some dots, to produce something like the following  1 | error_temp = error - ((numpy.linalg.norm(b, 'fro')) ** 2.0) ... | ... 5 | error -= (numpy.linalg.norm(b[j, :])) ** 2.0  I would like to be able to specify a few lines and ask listings to substitute them with dots and also print a few dots as its line number to indicate that it is skipping a few lines here. Also, when the skipping is over, resume to the actual line number as if the skipped lines were not skipped. Here is my minimal working example, which might not help though \documentclass{article} \usepackage{listings} \lstset{breaklines = true, frame = trBL, tabsize = 4, basicstyle = \small \ttfamily, keywordstyle = \color{blue}, stringstyle = \color{red}, rulecolor = \color{black}, numbers = left, numberstyle = \tiny}  \begin{document}  \begin{lstlisting}[language = Python, escapeinside = {(*@}{@*)}] error_temp = error - ((numpy.linalg.norm(b, 'fro')) ** 2.0) (*@ \cdots @*) error -= (numpy.linalg.norm(b[j, :])) ** 2.0 \end{lstlisting}  \end{document}  The problem with the code is, it would not skip line numbers and it can not print dots as line number for skipped lines. Please let me know if it is not clear of what I am trying to do, thanks in advance!


When I searched the net about magnetic field lines,  told something about contour lines and that magnetic materials placed along a magnetic field has some specific loci, which i did not understand. Can someone explain it to me in details.  Also how do we know that tangent to a magnetic field line gives the direction of magnetic field? I am very confused.


Which one should I use for page title?        Apple — Tasty Fruit   Apple — A Tasty Fruit   Apple — The Tasty Fruit      The article is only about tasty apple.


Is Tolkien's Middle-earth in our Universe?

I started reading The Hobbit to my daughter last night having read most of Tolkien's books in my youth, but haven't read them again for some years.  In the first few pages of The Hobbit, Tolkien talks about Hobbits being less common 'these days' such that 'big folks like us' probably don't know much about them. Taken in isolation, these first few pages strongly imply that the events take place in our world, presumably many many years ago.  However, this isn't the impression one gets from any of the other books, as far I can remember. Particularly The Silmarillion presents a creation story that takes some elements of the Ambrahamic faiths' creation stories, but is clearly a different story. I don't get the impression that Tolkien intends these other stories to be about our world.  What was Tolkien's likely meaning behind this passage?


How do I determine if a number is prime?  I'm writing a program where a user inputs any integer and from that the program determines whether the number is prime, but how do I go about that?


Have problems resizing NTFS disk. What should I do to create a 10GB free space disk?

Rakesh Godhala said:      You can select the partition as ntfs, resize the partition to 470GB.   So I click the /dev/sdb4, "change..." button, comes up "edit partition" dialog.  But after selecting "use as" to "NTFS" , there is no option for me to resize the C partition to 470GB.  So, what should I do to create a 10GB free space disk?  Could you please tell me which buttons I should hit to get over this problem?  All buttons are showed in the pictures I have uploaded at:  .  OK, I chose "something else" , because I cannot choose "replace windows 8 with Ubuntu".  I click "continue", so I faced the dialog (as the two pictures in previous question show).  I do not know which buttons should I hit.  This is the picture:


I have an SD card and it still says that error in sufficient storage

When I upgrade an Android application from Google Play, it gets downloaded, then the upgrade stops with the message      Error: Insufficient storage available.   I have a 32 GB SD card so I want to download to the SD card but it only puts apps on the internal memory. How can I get apps to install to the SD card?


Cardinality of the set of all total orders on $\Bbb{N}$

I need to compute the cardinality of the set of all total orders on $\Bbb{N}$.  Now, by definition there is an inclusion of this set into $\mathcal{P}(\Bbb{N}\times\Bbb{N})$, and so has cardinality $\le 2^{\aleph_0}$.  Now, finding an injection from $\mathcal{P}(\Bbb{N})$ to the set in question is much harder. I have the solution below, which I don't really understand and don't intuitively see. It feels like the usual $\le$ with some priority to elements of the set injected, but not quite.  Can anyone extrapolate some meaning from this, or provide a nicer solution?  (apologies for the laziness of not rewriting the solution)


I've seen an equals sign with a small exclamation mark on top being used to say "equals because of data that was given in the problem", for example for a boundary condition or initial value in a differential equation.  A rough picture of what I mean:       ! f(x) = 4   How do I typeset this in LaTeX? I've tried $=^!$ (which doesn't produce the desired result) and looked through the "relations" section of the  without success.


How to load more than 10 files with range in executable args?

I have this working command line expression: program --files path_to_mydir/mydata_[0-9].csv I would like to go from [0-100] but this is not working. program --files path_to_mydir/mydata_[0-100].csv Also, bonus ask, what do you call [0-10] wrt shell scripting and bash scripts? Thanks Edit: while similar this question is not asking about ls


IEEE rejects my paper saying that it is plagiarised

I submitted a paper to one of the journals in IEEE and editor responded with a rejection letter saying that it is plagiarized. But am very sure I have not copied any content or idea from other authors and have cited all references correctly.  I had submitted the paper in another journal of IEEE ( Transactions in Vehicular Technology) and the editor wrote back advising me to submit in a different journal as this was a survey paper.  What might be the reason? Can I write back to the editor? Please help.


I need to design a circuit so that it can convert 0 - 80 V DC to 0 - 3.3V DC. I need to give the output of a battery which is in the range of 0 - 80 V to an STM32F103 microcontroller. Since the operating voltage of the STM32 is 3.3V it is not possible to directly take the output. I need to convert it to a range of 0 - 3.3 V in order not to blast the controller. Can you please suggest a method to do that. Is it possible to achieve it using potentiometers. If yes can you please explain how the circuit should be?


Removing the broken package completely affects other packages

I was trying to install mega using dpkg and now, I have a broken package in my system, and when I run the Synaptic Package Manager and click on "Mark for complete removal" on the package, it gives me a warning box that says this will affect other packages.  The broken package is megasync:  Also, I am seeing this annoying white dash sign in a red circle on the top-right of my screen, and it says:  An error occurred, please run Package Manager from the right-click menu or apt-get in a terminal to see what is wrong. The error message was :'Error:BrokenCount>0'. This usually means that your installed packages have unmet dependencies. ..  Now, how should I go about it and remove the broken package completely from the system without messing up my system? Edit: sudo apt update voidRealm@voidRealm:~$ sudo apt update Get:1 http://in.archive.ubuntu.com/ubuntu focal InRelease [265 kB] Hit:2 http://dl.google.com/linux/chrome/deb stable InRelease                                                                          e Hit:3 https://deb.nodesource.com/node_12.x focal InRelease                                                                             Hit:4 http://in.archive.ubuntu.com/ubuntu focal-updates InRelease                                                                      Hit:5 http://in.archive.ubuntu.com/ubuntu focal-backports InRelease                                                                    Hit:6 http://security.ubuntu.com/ubuntu focal-security InRelease                                                                       Hit:7 https://brave-browser-apt-release.s3.brave.com stable InRelease                                                                  Hit:8 http://archive.canonical.com/ubuntu focal InRelease                                                                              Ign:9 https://repo.mongodb.org/apt/ubuntu focal/mongodb-org/4.0 InRelease                                            Hit:10 http://ppa.launchpad.net/dawidd0811/neofetch/ubuntu focal InRelease          Err:11 https://repo.mongodb.org/apt/ubuntu focal/mongodb-org/4.0 Release    404  Not Found [IP: 99.86.42.60 443] Hit:12 http://ppa.launchpad.net/maarten-baert/simplescreenrecorder/ubuntu focal InRelease Hit:13 http://ppa.launchpad.net/obsproject/obs-studio/ubuntu focal InRelease Hit:14 http://ppa.launchpad.net/ubuntuhandbook1/apps/ubuntu focal InRelease Reading package lists... Done                       E: The repository 'https://repo.mongodb.org/apt/ubuntu focal/mongodb-org/4.0 Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.  sudo-apt upgrade voidRealm@voidRealm:~$ sudo apt upgrade  ^Citing for cache lock: Could not get lock /var/lib/dpkg/lock-frontend. It is held by process 4557 (synaptic)... 16s


Any solutions to the functional equation?

while randomly thinking about functions, i tried to find general solutions to the equation:  $f(g(x)) = f(x)g(x)$  i managed to find one particular solution without any mathematical proof   for $ a  \in \mathbb{R}$:  $\hspace{2cm}$ $f(x)= x + a $ $\hspace{2cm}$ $g(x)= \frac{a}{x+a-1}$  Are there other solutions to this equation and can the solution that I found be obtained mathematically?


I'm currently trained in Algebra, Calculus and Statistics in high school level. Basically, I've no knowledge at all in number theory as this subject is not taken seriously in my country.  I was thinking to self-learning number theory by books. But the books I found in the internet are really hard and complicated for me as I've no number theory background at all.   Recently, I was asked by a 10 years old kid for a question which is related to number theory. I've no idea at all how to solve that, it was really embarrassed.   So can anyone recommend me some books for number theory which are suitable for me?


I have windows 8 pre-installed on my laptop. I downloaded ubuntu 12.04LS and installed it with wubi installer.But on restarting  windows 8 is loaded directly and I cant get access to ubuntu... will anyone please help me??


iTunes won't back up bc it's corrupt or incompatible

I can't back up my iPhone to iTunes and haven't been able to for almost a year.   I updated my phone, I've reinstalled iTunes, |I've deleted the backups existing in the preferences.  Any forum I've looked at only shows how to fix it on a Mac, and I don't have one of those. I've got a windows machine.


I'm creating a simple console application in python and I'd like to replicate the shell functionally where pressing the up or down key lets you cycle through previous commands.   I can easily store a list of previous commands but the hard part is catching up and down key presses. I have read that you can do this using a ui library like Qt but this seems overkill for such a simple thing.  Does anybody know of a lightweight and simple way to do this that uses no non standard modules?


Laplace transform of inverse gaussian distribution

Can someone write in details how i can derive the Laplace transform of the Inverse Gaussian distribution? I think i am missing something during the calculation of the interval which gives the Laplace transform $L(s)=E(e^{-sX})$, so can anyone help by providing the exact calculations?


Elliptic Curve and Divisor Example help (Step 1)

I have an elliptic curve $E$ over $\mathbb{F}_{11}$ defined by $y^2=x^3+4x$ with the point at infinity $\mathcal{O}$  I have a divisor of $E$, defined by $$D=\left[(0,0)\right]+\left[(2,4)\right]+\left[(4,5)\right]+\left[(6,3)\right]-4\left[\mathcal{O}\right]$$  I know that $\text{deg}(D)=1+1+1+1-4=0$ and it is clear that $\text{sum}(D)=\infty$  Therefore $D$ is the divisor of a function - we want to find this function  I am given \begin{align}\text{div}(y-2x)&=\left[(0,0)\right]+2\left[(2,4)\right]-3\left[\mathcal{O}\right]\\ \text{div}(x-2)&=\left[(2,4)\right]+\left[(2,-4)\right]-2\left[\mathcal{O}\right] \end{align}  I am then told that we can express $D$ as follows:  $$D = \left[(2,4)\right]+\text{div}\left(\frac{y-2x}{x-2}\right)+\left[(4,5)\right]+\left[(6,3)\right]-3\left[\mathcal{O}\right]$$  However, when I expand this back out, I get the following:  \begin{align}D &= \left[(2,4)\right]+\text{div}\left(\frac{y-2x}{x-2}\right)+\left[(4,5)\right]+\left[(6,3)\right]-3\left[\mathcal{O}\right]\\ &= \left[(2,4)\right]+\text{div}(y-2x)-\text{div}(x-2)+\left[\left(4,5\right)\right]+\left[(6,3)\right]-3\left[\mathcal{O}\right]\\ &= \left[(2,4)\right]+\left(\left[(0,0)\right]+2\left[(2,4)\right]-3\left[\mathcal{O}\right]\right)-\left(\left[(2,4)\right]+\left[(2,-4)\right]-2\left[\mathcal{O}\right]\right)+\left[\left(4,5\right)\right]+\left[(6,3)\right]-3\left[\mathcal{O}\right]\\ &= \left[(0,0)\right]+2\left[(2,4)\right]+\left[(4,5)\right]+\left[(6,3)\right]+2\left[\mathcal{O}\right]-\left[(2,-4)\right] \end{align}  which clearly isn't equivalent to the original $D$ unless $$\left[(2,4)\right]+2\left[\mathcal{O}\right]-\left[(2,-4)\right]=-4\left[\mathcal{O}\right]$$  Can anyone either explain what I've done wrong or show me how I can obtain the above equation please    This question comes in three parts:   Step 1 - This one Step 2 -  Step 3 -


How do I wrap a macro definition in an environment?

I'm creating a style file, and want to store the body text of the abstract environment so that I can put it on my custom titlepage. I could have required that my users enter the abstract as  \customabstract{Abstract text goes here}`   which I would have implemented as something like  \newcommand{\customabstract}[1]{\gdef\abstracttext{#1}}   However, I would prefer that the user is able to use environment notation,  \begin{customabstract}Abstract text goes here\end{customabstract}   To do this, I thought I could define something like  \newenvironment{customabstract}{\gdef\abstracttext\bgroup}{\egroup}   But this definition makes \abstracttext expand to \bgroup, which is not what I wanted. I tried to solve the problem by \expandafter,  \newenvironment{customabstract}{\expandafter\gdef\expandafter\abstracttext\bgroup}{\egroup}   but this results in a runaway error.  Is there any way to acheive what I want? Answers that helps me understand the inner workings of TeX (instead of just referring to a custom package) are preferred.


Why redirecting output sometimes produces an empty file?

The power of shell pipeline is so great that sometimes fails me.   Example  Just as an example, the pipeline  echo abc > file.txt cat file.txt | sed 's/a/1/' > file.txt   gives me an empty file.txt. Realizing that the shell probably calls > first, I made a change:  echo abc > file.txt {cat file.txt | sed 's/a/1/'} > file.txt   Again it surprises me by another empty file file.txt. An ugly way that finally works is  echo abc > file.txt echo $(cat file.txt | sed 's/a/1') > file.txt   which forces the shell to run a subshell first, and then redirect.  Question  While I'm aware of better practice of sed, which allows you to get rid of echo, cat, grep.. etc, what I am curious about here is to learn shell's grammar completely. This questions is not about how to fix the particular problem above.  Q1(EDIT: off-topic) Is there a good resource for me to learn the grammar?  I'm afraid that different shells could have different grammars, so  Q2 Can I make shell verbose, and see clearly what it is doing every completely every single time I run a command?  Q3(EDIT: off-topic) Any other advice on good practices? Thank you!


Booting from Ubuntu ISO CD - Windows 7 partitioning

Do I partition Windows 7 hard disk before I install Ubuntu using disk utility in Windows 7? Or do I do it with my Ubuntu ISO CD after booting? And can I choose the size of the partition using Ubuntu ISO CD?


How to stop Blender from making the CPU overheat?

Apparently my CPU or GPU overheats when Blender renders more than a few minutes.  The computer suddenly powers down, taking down all running apps, email I'm writing, etc.  This is almost never a problem with still scenes, which finish soon enough, but often with animation renders.    The problem occurs with either Cycles or BI renders.  I'm running on a custom-built quad core 64-bit linux desktop system.  (I'm not the one who built it. I am  a knuckle-dragging caveman with hardware issues.) (Yes, all the fans are blowing and dust has been cleaned off.)  So far the only way to prevent this for now is to choose in camera properties: Performance, Threads, Fixed, 1.     Someday, I'll get better hardware, but in the meantime, I suspect Blender could run indefinitely, even with multiple threads, if I could make it pause for perhaps one minute between each frame when animating, just to cool down. How to make this happen?  At least, a way to run an arbitrary Python script between frames, or once per minute during any rendering. Such a script could contain a sleep stat  Even better, if Blender could throttle its rendering effort based on readings of the CPU temperature sensor.   Is that possible?  UPDATE: I've nearly forgotten about this issue, since writing a quick Python script to watch the CPU temperature, sending SIGSTOP and SIGCONT as gandalf3 describes. Zero crashes ever since. I reboot my machine once or twice per year for kernel upgrades, otherwise it's 100% up.  ANOTHER UPDATE: I took the machine apart, popped off the CPU heatsink, and applied fresh thermal paste.  Ever since, the CPU temperature has been running something like 30deg (C) cooler all the time.  Zero shutdowns, and I don't use the Python script any more unless I'm feeling paranoid.


How can I find $\lim_{n\to \infty}\left(\cfrac{1^p+2^p+\cdots+ n^p}{n^p}-\cfrac{n}{p+1}\right)$?

Please help me to find the following limit:  $$\lim_{n\to \infty}\left(\cfrac{1^p+2^p+\cdots +n^p}{n^p}-\cfrac{n}{p+1}\right),$$ where $p\in \mathbb{N}$.


needed to create some content types that have a field that creates a vote, as a poll. Have you tested the modules and Advanced Poll Pollfield but as yet there is not a production version-these contain some errors.  Someone has a solution in order to implement content types with polls?


Why sample with replacement in bootstrap?

If I want to test the accuracy of a predicted coefficient based on my data set $N$, then I create a bootstrap sample by sampling from by data set with replacement $N$ times, and then refit my model and calculate the estimate once again.   Why do we sample WITH replacement?


How do I solve this tricky definite integral ?!

$$I=\int\limits_0^1\dfrac{x^2-1}{\ln x}\mathrm dx$$  I tried numerous substitutions but nothing seems to work.. any ideas ???!


How to get before/after information from change events

I'm changing a field in my lightning component and handle the change with a default lightning change handler. I can not make use of  since I'm in a loop,  (already created )  <aura:iteration items="{!v.values}" var="value">     <ui:inputNumber change="{!c.numberChanged}" value="{!value}" /> </aura:iteration>   In my controller I'm now trying to handle that change. But to do so, I need the the old field value. Is there anything in the retrieved event object, that contains this information? I digged deeper into the event methods and tried to output whatever I found, but there was nothing useful. Is the event technology documented somewhere in detail?  numberChanged: function(cmp, evt, helper) {     console.log(evt.getEventType());     console.log(evt.getType());     console.log(evt.getName());     console.log(evt.getPhase());      console.log(evt.getSource());     console.log(evt.getSource().getEvent());     console.log(evt.getSource().toString()); },   Output:        COMPONENT   ui:change   change   bubble   -   [Object with a few methods]   null   SecureComponentRef: markup://ui:inputSmartNumber {3765:949;a}{ key:    {"namespace":"MY_NAMESPACE"} }      3765:949 seems to be an internal identifier, it's not the numbers I changed.    EDIT1: since I found , it feels like there is more information behind the getSource(), but where is it documented?    EDIT2: Added more information to make clear why <aura:handler name="change" ...> won'work


Unable to Install Wine on Ubuntu 14.04.2?

It's giving me following error mentioned below after trying to install wine v1.7 on ubuntu 14.04.2:   libgbm1 : Depends: libgl1-mesa-dri  libudev1 : Depends: libcgmanager0 but it is not going to be installed  wine1.7 : Depends: wine1.7-amd64 (= 1:1.7.44-0ubuntu1) but it is not going to be installed            Depends: binfmt-support (>= 1.1.2)            Depends: wine1.7-i386 (= 1:1.7.44-0ubuntu1)            Recommends: cups-bsd            Recommends: gnome-exe-thumbnailer but it is not going to be installed or                        kde-runtime but it is not going to be installed            Recommends: ttf-mscorefonts-installer but it is not going to be installed            Recommends: winetricks but it is not going to be installed E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.


The exact value of $\lim_{n \to \infty} \frac{a_n}{\sqrt[4]{n^3}}$

Let $a_1=1$ and $a_{n+1}=a_n+\frac{\sqrt{n}}{a_n}$. If it exists, find $$\lim_{n \to \infty} \frac{a_n}{\sqrt[4]{n^3}}$$   Obviously, $a_n \to \infty$ and $a_n$ is strictly increasing. I tried to get rid of that $n$ in the limit and get only $a_n$ terms in the numerator so that I could substitute $a_n$ to $x \to \infty$ and maybe use L'Hospital to finish. But $a_{n+1}, a_n$ and $\sqrt{n}$ are so tightly connected that I didn't manage to do that.  Another approach was Cesaro-Stolz, writing the limit as $$\lim_{n \to \infty}\left(\sqrt[4]{\frac{\sqrt[3]{a_n^4}}{n}}\right)^3=\left(\lim_{n \to \infty}\left(\sqrt[3]{a_{n+1}^4}-\sqrt[3]{a_n^4}\right) \right)^\frac{3}{4}$$ but I encountered the same issue. I'm even wondering if there is a nice closed form for the limit.  Edit: As pointed below, if the limit exists, then its value is $\frac{2}{\sqrt{3}}$. How can we prove that it exists?


a number of children has gone to school or have gone to school

Please help, in this sentence is "a number" an attribute or the subject of the sentence?


How to do division of two numbers which are already under modulo 'm'?

How to do division for the following example?  Case 1 : Without modulo  n1 = 40, n2 = 8  Quotient = n1/n2 = 5    Case 2 : With modulo  m = 6  n1 = n1 mod m = 4 (AND) n2 = n2 mod m = 2  Quotient = 4 / 2 = 2  Now,In case 1, Quotient = 5, but in case 2, Quotient = 2. How to do division on numbers such that both numbers are already under modulo 'm'?


TextView change text first click doesn't work

This TextView has two functions. Firstly, it can switch the password between two status, HIDE and SHOW. Then it change the TextView text between "SHOW" and "HIDE". The first function can work perfectly. But the second didn't work very well. Whenever I open my app. The first click on the TextView, It only change the password status, but not the TextView text. Unless I click multiple times, both function would be work. After several test, I found only the TextView text can not work when I clicked the widget at the very first time. I am a noob on Android Studio, so I think this might be just a simple question. Are there anyone can tell me why this happened, please! Thank you!     TVtoggle.setOnClickListener(new View.OnClickListener() {         @Override         public void onClick(View v) {             if (TVtoggle.getText() == "SHOW") {              ETpassword.setInputType(InputType.TYPE_TEXT_VARIATION_VISIBLE_PASSWORD);                 ETpassword.setSelection(ETpassword.length());                 TVtoggle.setText("HIDE");             }             else {                 TVtoggle.setText("SHOW");                  ETpassword.setInputType(InputType.TYPE_CLASS_TEXT |                  InputType.TYPE_TEXT_VARIATION_PASSWORD);                 ETpassword.setSelection(ETpassword.length());             }         }     });


How to get XY coordinates of a control at runtime in WPF?

How to get XY coordinates of a control at runtime in WPF ?


I have a 32GB iPad 1 that I have had running for about six years. Recently, there was a virus and I had to reset it. I did so successfully. It has iOS 5.1.1 (9B206) installed.  In General > Software Update I see "iOS 5.1.1 Your software is up to date".  When I go to the App Store and try to install Netflix, I am informed that "this application requires iOS 9.0 or later". Obviously, I can't do so.  Is there a way to install ANY version of Netflix on my iPad?


What does it mean for a variable to be free for something?

"If $\mathscr{B}$ is a wf and $t$ is a term, then $t$ is said to be free for $x_i$ in $\mathscr{B}$ if no free occurrence of $x_i$ in $\mathscr{B}$  lies within the scope of any quantifier $(\forall x_j)$, where $x_j$ is a variable in $t$."   This is how Mendelson defines the expression 'free for $x_i$ in $\mathscr{B}$'. He goes on to say that it means that, if $t$ is substituted for all free occurrences (if any) of $x_i$ in $\mathscr{B}(x_i)$, no occurrence of a variable in $t$ becomes a bound occurrence in $\mathscr{B}(t)$'.   I still can't understand what 'free for' means. Could anyone provide examples along with explanations?   Mendelson also distinguishes between 'free for', 'free' and 'free occurrence', distinctions that I haven't yet fully grasped.


See permissions for new files on a given directory

I don't understand how my Linux machine is operating on new files.   I have an Amazon Linux AMI (RHEL based distro) and when I execute umask I get 0002, so I get whenever I create new stuff other users won't get write access.  But then I go to my home directory and I type:  $ mkdir myDir $ touch myDir/myFile $ ls -l | grep myDir   and I get  drwxrwxr-x 2 myself myself 4096 May 11 22:37 myDir   and for the folder:  $ ls -l myDir -rw-rw-r-- 1 myself myself 0 May 11 22:37 myFile   So apparently there's more going on there then my umask, since myFile permissions are more restrictive than just write protection.  Digging deeper, if I try:  $ sudo touch /var/run/myPidFile.pid $ ls -l /var/run/ | grep myPidFile.pid -rw-r--r-- 1 root    root       0 May 11 22:42 myPidFile.pid   So myPidFile.pid gets a much more restrictive default permission, under /var/run then myFile gets under my home folder.  We could blame the root umask but if I run umask under root I get 0022 which is indeed more restrictive then my user's 0002 umask but still doesn't explain how the execution bit permission isn't set.  So how can I understand a folder's default permission on Linux?


Let $A$ be a nonsingular $n \times n$ matrix, $\|\cdot\|$ be any natural norm, and $K_{p}(A)=$ $\|A\|_{p}\left\|A^{-1}\right\|_{p} .$ Let $\lambda_{1}$ be the smallest and $\lambda_{n}$ be the largest eigenvalues of the matrix $A^{t} A$ (b) Show that $K_{2}(A)=\sqrt{\frac{\lambda_{n}}{\lambda_{1}}}$. (Hint: One should use the $\|A\|=\sqrt{\rho\left(A^{t} A\right)}=\sqrt{\rho\left(A A^{t}\right)}$ relation) For part $(b)$, it seems minimal eigenvalue of matrix $A$ will be the largest eigenvalue of the inverse of matrix $A$, so we have to use this idea but could not understand formally why square roots are needed for $K_{2}(A)$ and how spectral radius is necessary for this part?!


Can I work on my projects (self-employed) while visiting another country?

I am self-employed as an indie game developer and would like to visit New Zealand and Australia to do some touristing.  Can I work on my projects (programming/design/online marketing/support) while visiting another country, say New Zealand or Australia? Can I do that for a month-long visit? What about longer periods: 90 days, 6 months? Can I do that under a regular tourist visa or do I need a different visa? Do I need to worry about taxes?  Not as important, but:  Does the answer change if I (a) take on any (online) freelance work or (b) hire out some (online) freelance work while there?  Note that I am a US citizen. Also, assume things will return to the pre-COVID normal and the travel will take place long after the pandemic is over. Similar questions, but asking about the UK:  (answer is no?) and Japan:  (conflicting answers, but it also seems like a no?).


The meaning of though in the end of this sentence

I was reading the declaration that Michael Jackson´s daugther posted about her smoking cigarettes these past days, outside a restaurant. And she wrote a sentence like this:  "Sure as hell beats everything else in my past though".  I get that when she refers to " sure as hell beats everything else in my past", she means that the action of smoking isn´t the worst thing she has done in her life. But I would like to understand what "though"means in the end of the sentece of hers.  Thank you, folks.


Evaluate $\tan^{2}(20^{\circ}) + \tan^{2}(40^{\circ}) + \tan^{2}(80^{\circ})$.  Can anyone help me with this? Thank You!


I'm currently playing a Deva Wizard in a D&D 4th campaign, and I often found that I would like to have more options for my at-will powers. I know I could have made a Human, but I didn't.  Is there any way to have more at-will power(s) at some point, or am I "stuck" with only 2 ?


I am trying to install oracle database in Ubuntu 16.04 LTS. I had unzipped the oracle database file in opt folder,but now when I am trying to give execute right to the sqldeveloper file using chmod +x sqldeveloper.sh, it's throwing this error:  chmod: changing permissions of 'sqldeveloper.sh': Operation not permitted


First-order logic and second-order logic confusion

First-order logic uses only variables that range over individuals (elements of the domain of discourse); second-order logic has these variables as well as additional variables that range over sets of individuals. For example, the second-order sentence $\forall P\,\forall x (x \in P \lor x \notin P)$ says that for every set $P$ of individuals and every individual $x$, either $x$ is in $P$ or it is not (this is the principle of bivalence). ("Second-order logic", Wikipedia)   And     In the formal language of set theory, the axiom schema is:   $\forall w_1,\ldots,w_n \, \forall A \, \exists B \, \forall x \, ( x \in B \Leftrightarrow [ x \in A \land \phi(x, w_1, \ldots, w_n, A) ] )$   Comparing and contrasting these two, I find that in the latter case, set $A$ can be considered as set of individuals that was quanitifed by universal quantifier. So, how is this different from second-order logic (in the first case, I would be referring to set $P$.)?


When I first heard of , I originally thought it was quite a powerful cantrip that would allow the castor to sacrifice 1 attack in order to be granted insight into the target's elemental weaknesses and resistances. It reminded me of my first campaign when I walked into it at level 4 and felt lost hearing my DM state "your attack seems to have done nothing" even when I knew it was a hit.   However, I now realize that was a false understanding of the rules. As such, I was wondering:  Is there a spell, item, or other game feature that would give my character insight to an enemy's weaknesses and resistance?  I am curious about any possible solution that would let a group know why the arcane wizard is not taking any damage in the middle of a fight, for example.


Why can I vote to reopen a deleted question?

I've seen .  Voting to undelete will not work because it was deleted by a moderator, but I managed to vote for reopening for some reason.  I doubt this is intentional, perhaps not as important, but still.


how do I convert unix string to proper datetime format in python

I have a unix string. And want to display that in tableau date format which expects 5 arguments   import dataextract as tde from datetime import datetime  tdefile=tde.Extract('USCSVExtract.tde') tableDef.addColumn('CreationDate', tde.Type.DATE)  date_object = datetime.strptime(story.CreationDate, '%Y-%m-%d-%H:%M:%S.Z') newrow.setDate(3,date_object) table.insert(newrow) tdefile.close()   value of story.CreationDate is 2014-10-31T20:02:36.622Z  I am unable to figure out T20:02:36.622Z this part


Wedge sum of circles and the Infinite Earring

The (countably infinite) wedge sum of circles is quotient of  disjoint countable union of circles $\amalg S_i$, with points $x_i\in S_i$ identified to a single point, while the infinite earring H is the topological space defined by the union of circles in the Euclidean plane $\mathbb{R}^2$ with center $(1/n, 0)$ and radius $1/n$ for $n = 1, 2, 3, ...$. In the definition of countably infinite wedge sum of circles, it is not specified the size of circles, the points which to be identified to a single point etc. So we can take disjoint union of circles of radius $1/n$ and identify a point from each to a common single point to get the infinite earring. I couldn't understood the difference between these two topological spaces. Can one explain more precisely the difference between these two spaces?


I have 2 questions.  1- How to use a diagonal seperator for the table hearders n and k in a good way.  2- How to align the back of the arrow to the rightand the head to the left of the numbers?    \documentclass{article}  \usepackage{tikz} \usetikzlibrary{matrix,chains,scopes,arrows}  \begin{document} \begin{center}     \begin{tikzpicture}       \matrix[matrix of math nodes,column sep=1em,row sep=0ex] (ex5mx) {         n\backslash{}k & 0 & 1 & 2 \\         0 & -0.3887696362 & ~ & ~ \\         1 & -0.3892561049 & -0.3894182612 & ~ \\         2 & -0.3893777792 & -0.3894183372 & -0.3894183423 \\       };        %\draw[thin,black] ([xshift=0em,yshift=0em]ex5mx-1-1.north west) -- ([xshift=0em,yshift=0em]ex5mx-1-1.south east); %\drule       \draw[thin,black] ([xshift=0.5em,yshift=0em]ex5mx-1-1.north east) |- ([xshift=1.058em,yshift=0em]ex5mx-4-1.south east); %\vrule       \draw[thin,black] ([xshift=-0.5em,yshift=0.25em]ex5mx-1-1.south west) |- ([xshift=3em,yshift=0em]ex5mx-1-4.south east); %\hrule        %1st rows       {[start chain,every on chain/.style={join={by <-*, blue!30}}]         \chainin (ex5mx-3-3);         {[start branch] \chainin (ex5mx-2-2); }         {[start branch] \chainin (ex5mx-3-2); }       }        {[start chain,every on chain/.style={join={by <-*, blue!30}}]         \chainin (ex5mx-4-3);         {[start branch] \chainin (ex5mx-3-2); }         {[start branch] \chainin (ex5mx-4-2); }       }        %2nd rows       {[start chain,every on chain/.style={join={by <-*, blue!40}}]         \chainin (ex5mx-4-4);         {[start branch] \chainin (ex5mx-3-3); }         {[start branch] \chainin (ex5mx-4-3); }       }      \end{tikzpicture}     \end{center} \end{document}