I have a paypal.class.php at SITE_URL/paypal/papal.class.php   getting this error :      Warning: include_once(/var/www/clients/client1/web15/web/includes/bootstrap.inc): failed to open stream: No such file or directory in /home4/solution/public_html/taconsultant/paypal/paypal.class.php on line 3      Warning: include_once(): Failed opening '/var/www/clients/client1/web15/web/includes/bootstrap.inc' for inclusion (include_path='.:/opt/php54/lib/php') in /home4/solution/public_html/taconsultant/paypal/paypal.class.php on line 3      Fatal error: Call to undefined function drupal_bootstrap() in /home4/solution/public_html/taconsultant/paypal/paypal.class.php on line 4   I am not able to access the user_load() function or any other Drupal function or variable in it. Is there a way to access Drupal variables in that particular file?  I have included it like this.      require_once '../includes/bootstrap.inc';      global $user;     $uid =$user->uid;          class paypal_class {             var $last_error;                 // holds the last error encountered             var $ipn_log;                    // bool: log IPN results to text file?             var $ipn_log_file;               // filename of the IPN log            var $ipn_response;               // holds the IPN response from paypal               var $ipn_data = array();         // array contains the POST values for IPN             var $fields = array();           // array holds the fields to submit to paypal              function paypal_class() {                // initialization constructor.  Called when class is created.                $this->paypal_url = 'https://www.paypal.com/cgi-bin/webscr';                $this->last_error = '';                $this->ipn_log_file = '.ipn_results.log';               $this->ipn_log = true;                $this->ipn_response = '';                // populate $fields array with a few default values.  See the paypal               // documentation for a list of fields and their data types. These defaul               // values can be overwritten by the calling script.                $this->add_field('rm','2');           // Return method = POST               $this->add_field('cmd','_xclick');              }             function add_field($field, $value) {                // adds a key=>value pair to the fields array, which is what will be                // sent to paypal as POST variables.  If the value is already in the                // array, it will be overwritten.                $this->fields["$field"] = $value;            }

This is what I have right now:  <?php     define('DRUPAL_ROOT', '/var/www/clients/client1/web15/web');     include_once(DRUPAL_ROOT . '/includes/bootstrap.inc');     drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL); //  drupal_flush_all_caches();        $users = views_get_view_result('userlist', 'uid_list');     $i = 0;     foreach ($users as $user) {         $filename = 'sites/default/files/generated_pdfs/individual_pdf_report_' . $user->uid . '.pdf';         generate_employee_pdf($user->uid, $filename);         error_log('Generated ' . $filepath);         $i++;     }     // create object     $zip = new ZipArchive();     // open archive     if ($zip->open("sites/default/files/generated_zips/individual-reports.zip", ZIPARCHIVE::CREATE) !== TRUE) {         die ("Could not open archive");     }     // initialize an iterator     // pass it the directory to be processed     $iterator = new RecursiveIteratorIterator(new RecursiveDirectoryIterator("sites/default/files/generated_pdfs/"));     // iterate over the directory     // add each file found to the archive     foreach ($iterator as $key=>$value) {         $zip->addFile(realpath($key), $value->getFilename()) or die ("ERROR: Could not add file: $key");     }     // close and save archive     $zip->close(); ?>   I'm getting a bunch of errors from the above when run standalone. Works fine in my module. Some of the errors are:  Warning: Invalid argument supplied for foreach() in drupal_depth_first_search() (line 56 of /var/www/clients/client1/web15/web/includes/graph.inc). Warning: Invalid argument supplied for foreach() in _module_build_dependencies() (line 229 of /var/www/clients/client1/web15/web/includes/module.inc). Warning: include_once(sites/all/modules/views_bulk_operations/actions/archive.action.inc): failed to open stream: No such file or directory in views_bulk_operations_load_action_includes() (line 56 of /var/www/clients/client1/web15/web/sites/all/modules/views_bulk_operations/views_bulk_operations.module).


Click image for larger version  It pops up randomly when I'm using my phone. However, it ALWAYS pops up when I open Google maps. It then seems to emulate a repeated clicking motion, which freezes my phone to the point I have to do a hard restart.  I am using am HTC One m8  (I'm not sure about this but I'm pretty sure I saw a literal mouse cursor come out of the blue dot one day)  I'm naming it the BDOD (Blue Dot Of Death)

Forgive me for the unclear title. Some time ago, my HTC M8, which is rooted and runs on a  showed something weird. Firstly, in the Google Maps App a mysterious blue dot appeared, that captures the screen completely and makes it impossible to quit or use the application. It looks like this (I could make a screenshot)     When this happens in Maps, the only thing I can do is a hard restart with Power+Volume Up.  Since I have seen this occasionally in the camera app as well, I suspect it is not a bug of Maps itself. I know that the Venom ROM is not standard but maybe this is connected to some setting and anyone has seen this. Btw, the Venom ran smoothly for almost 3 years now.  Question: Has someone a clue what this could be and how I can get rid of it?


I remember seeing this somewhere a while ago - I'd given it a go but it was - and still is - beyond my capabilities. The problem came with the tag: "requires knowledge of analytic number theory". I am not necessarily asking for a solution.  $$\left[\;\sum_{n\;\text{odd}} (-1)^{\frac{n-1}{2}}\frac{ \log n}{\sqrt{n}} \right]\left[\;\sum_{n \;\text{odd}} (-1)^{\frac{n-1}{2}}\frac{1}{\sqrt{n}} \right]^{-1}$$ Does anyone know where this is from? I am equally puzzled by the "hint". Does it have a number-theoretic interpretation that someone with basic (i.e. olympiad-level) knowledge of number theory could understand?  Would appreciate a reference if this appears in the literature somewhere.

This is another intriguing formula coming from Ramanujan's letter to G. H. Hardy dated 16th Jan 1913 $$\frac{\log 1}{\sqrt{1}} - \frac{\log 3}{\sqrt{3}} + \frac{\log 5}{\sqrt{5}} - \cdots = \left(\frac{\pi}{4} - \frac{\gamma}{2} + \frac{\log 2\pi}{2}\right)\left(\frac{1}{\sqrt{1}} - \frac{1}{\sqrt{3}} + \frac{1}{\sqrt{5}} - \cdots\right)$$ where $$\gamma = \lim_{n \to \infty}\left(\frac{1}{1} + \frac{1}{2} + \cdots + \frac{1}{n} - \log n\right)$$ is the Euler's constant.  This seems really a different kind of series dealing with $\sqrt{n}$ in the denominator and is so unlike the usual series for $\log (1 + x)$ or $\arctan x$ or even Abel's function $\sum x^{n}/n^{2}$. Please help me out in proving the above identity. Any reference having a proof would also be of great help.


I want to click on file to inherit the name for the file being saved. I can't read file names in the dialog box because the color is too faint. This is the same question as   That question does not have an answer but I don't have enough points to interact there so I have to post a new question.    Edited to add screen shots I tried to calibrate the monitor which no effect and did not change the readability of "unavailable" file names. I have added screenshots of previous operating systems to compare: Please tell me how Mojave is not to blame here:

I just updated my iMac to Mojave, and am still trying to setup my preferences.  I tried dark mode, but did not like it (half of me apps seem to ignore it anyway).  I switched to light mode, but this too has problems. The File Save dialog shows a list of Directories and existing files, but the latter are very light grey, almost indistinguishable from the background.    I have searched the Preferences menu, but can't seem to find any setting to set normal contrast levels like in High Sierra.


For Stiefel manifold, it contains all the orthogonal column matrices  $$St(d,M) = \{X \in R^{M \times d} | X^TX = I\}$$  For Grassmann manifold, it is  $$Gr(d,M) = \{col(X), X \in R^{M \times d}\}$$  For an objective problem $$ \min_{X \in St(d,M)} f(X)$$  can we solve above optimization using  $$ \min_{X \in Gr(d,M)} f(X)$$  Is above transform legal? or $f(X)$ should satisfy some conditions?

I'm working on an optimization problem on manifolds and I'm having a bit of a conceptual issue with choosing between the Grassmann and Stiefel manifolds. Grassmann(2, 3) is the linear subspace of dimension 2 within the space $\mathbb{R}^3$, so all planes through the origin. So a point on the manifold corresponds to a plane, invariant to linear mixing of support vectors. Stiefel(2, 3) would be all possible planes through the origin that are the span of two orthonormal vectors. So my questions are:   Does that mean that a point on the Stiefel manifold is also a point on the Grassmann manifold (in the sense that all linear subspaces of a given span can be reduced to the same orthonormal components)?  What do I gain by optimizing on the Grassmann vs the Stiefel manifold, if the parametrization of the points is the same?


In a previous question () it was asked whether nlme  can reproduce Welch's t-test.   Below is an abridged version of this older question:      A standard independent samples t-test (where it is assumed that the samples being compared are drawn from populations with equal variance) can be expressed as follows:           $$Y_i = \beta_0 + \beta_1 X_i + \varepsilon_i$$         where $Y$ is the outcome and $X$ is a binary variable corresponding to group membership. The significance test of $\beta_1$ will produce the same t statistic as the standard independent samples t-test. Thus, the two commands below produce the same statistics (with the same degrees of freedom):   t.test(extra~group, data = sleep, var.equal = TRUE)   lm(extra~group, data = sleep)   The provided answer to this question indicated that using gls (in the nlme package) with specificed weights   weights=varIdent(form = ~ 1 | group))    would do the trick.  I am curious whether this can also be implemented in lme4 (using lmer). When going through the help file of lme4 I could not find anything that corresponds to the weight option in nlme::gls.

How can Welch's t-test be expressed as a generalized least squares model?  A standard independent samples t-test (where it is assumed that the samples being compared are drawn from populations with equal variance) can be expressed as follows:  $$Y_i = \beta_0 + \beta_1 X_i + \varepsilon_i$$  where $Y$ is the outcome and $X$ is a binary variable corresponding to group membership. The significance test of $\beta_1$ will produce the same t statistic as the standard independent samples t-test. Thus, the two commands below produce the same statistics (with the same degrees of freedom):  t.test(extra~group, data = sleep, var.equal = TRUE) lm(extra~group, data = sleep)   Because a Welch's t-test allows for unequal variances between the samples being compared, my guess is that it would be equivalent to a generalized least squares procedure. The question then is, what call to gls (if this indeed the correct way of conceptualizing the problem) would produce the same results (including degrees of freedom) as:  t.test(extra~group, data = sleep, var.equal = FALSE)


/^(file.+)\.pdf$/g   This should be capturing the file names except the extension.  But that is not happen in my case.    Got this solution from this site

I want to match a portion of a string using a  and then access that parenthesized substring:  var myString = "something format_abc"; // I want "abc"  var arr = /(?:^|\s)format_(.*?)(?:\s|$)/.exec(myString);  console.log(arr);     // Prints: [" format_abc", "abc"] .. so far so good. console.log(arr[1]);  // Prints: undefined  (???) console.log(arr[0]);  // Prints: format_undefined (!!!)   What am I doing wrong?    I've discovered that there was nothing wrong with the regular expression code above: the actual string which I was testing against was this:  "date format_%A"   Reporting that "%A" is undefined seems a very strange behaviour, but it is not directly related to this question, so I've opened a new one, .    The issue was that console.log takes its parameters like a printf statement, and since the string I was logging ("%A") had a special value, it was trying to find the value of the next parameter.


I had always this problem when the notebook was suspended. But normally with a reboot everything goes right, but not now! Can someone help me?  After done lspci -nnk | grep Net -A2  02:00.0 Network controller [0280]: Qualcomm Atheros AR9485 Wireless Network Adapter [168c:0032] (rev 01)     Subsystem: Lite-On Communications Inc AR9485 Wireless Network Adapter [11ad:6627]     Kernel driver in use: ath9k     Kernel modules: ath9k

I recently bought a new computer that has an Atheros AR9485 wireless NIC. So far it has been working ok except this one issue: Randomly (as far as I can tell) it will completely lose the internet connection. The indicator in the top panel will still say we are connected but the machine has no internet connectivity whatsoever.    I've been able to get it working again by simply disconnecting from my wireless AP and then reconnecting, but this is annoying. Is there anything I can do to make the connection more stable?    I have tried passing the nohwcrypt=1 to the driver, but that made it impossible to connect to any AP, it just infinity attempted to connect.  sudo modprobe -rfv ath9k sudo modprobe -v ath9k nohwcrypt=1   I've also tried upgrading my kernel to Linux 4.0 but the problem persists.    Exact chip:  02:00.0 Network controller [0280]: Qualcomm Atheros AR9485 Wireless Network Adapter [168c:0032] (rev 01)     Driver:    $ ls /sys/class/net/wlan0/device/driver/module/drivers pci:ath9k  platform:ath9k     and lsmod:  user@host:~$ lsmod | grep -e ath -e ndis ath3k                  20480  0  bluetooth             491520  9 bnep,ath3k,btusb ath9k                 147456  0  ath9k_common           32768  1 ath9k ath9k_hw              458752  2 ath9k_common,ath9k ath                    32768  3 ath9k_common,ath9k,ath9k_hw mac80211              724992  1 ath9k cfg80211              540672  4 ath,ath9k_common,ath9k,mac80211    output from wireless script:    I'm running Ubuntu 15.04 on Linux 4.0.0-040000-generic on a Lenovo G510.   I'm wondering now if I could possibly have anything to do with my wireless mouse, which also operates on 2.4GHz..


I am trying to use to insert a date to my sqlite database.  public CardHolder(String firstName, String lastName, String barcodeNb,                          Date dateOfBirth,Date expiryDate)   Where I initiated this instance in the mainActivity    CardHolder person1 =new CardHolder("John","example","123123",new                     java.sql.Date(1993,9,3),new java.sql.Date(1993,9,3));   But it shows that java.sql.Date is deprecated, what should I use instead?

I am trying to use a  as input and then creating a query with it - so I need a .    I was surprised to find that it couldn't do the conversion implicitly or explicitly - but I don't even know how I would do this, as the Java API is still fairly new to me.


Provide a complete proof for the statement: prove that $\underbrace{\sqrt{2+\sqrt{2+\sqrt{2+\dots+\sqrt{2}}}}}_{\text{n radicals}}=2\cos{\frac{\pi}{2^{n+1}}}$

so I stumbled upon this equation/formula, and I have no idea how to prove it. I don't know how should I approach it: $$ \sqrt{2 + \sqrt{2 + \cdots + \sqrt{2 + \sqrt{\vphantom{\large A}2\,}\,}\,}\,}\ =\ 2\cos\left(\vphantom{\Large A}\pi \over 2^{n + 1}\right) $$  where $n\in\mathbb N$ and the square root sign appears $n$-times.  I thought about using sequences and limits, to express the LHS as a recurrence relation but I didn't get anywhere.  edit: Solved, thanks for your answers and comments.


I have an array that has the names of people. I want to use this array to cycle through every single person in the array and make a button with the name. That button will then get to console.log the name of the person. The problem here is that I don't think I can use onClick in a template string lateral. Here's something that it looks like.   let content = document.getElementById("content") var array = ["John", "Adam", "Sid", "Edward"]  array.forEach(element => {    function runEvent() {     console.log(element)   }   content.innerHTML += `<button onclick="runEvent()">${element}</button>` }) <div id="content"> </div>    How do I do this?

What is the scope of variables in javascript? Do they have the same scope inside as opposed to outside a function? Or does it even matter? Also, where are the variables stored if they are defined globally?


Say that I have good, collision resistant hash function H. Given a message M, the typical usage is h=H(M) to get it's hash.  Now, I want to propose two alternative methods of using this hash function, and compare them to the original function. First, I split my message M into equally sized chunks M1, M2, ..., Mn.  First method: the hash would be h=H(M1)⊕h(M2)⊕...⊕h(Mn) (⊕ is XOR).  Second method: the hash would be h=H(M1,1)⊕h(M2,2)⊕...⊕h(Mn,n), where comma means concatenation.  Now, it's obvious that the first hashing method is poor - I can shuffle the chunks around, and add two equal chunks without changing the resulting hash. But what about the second method? Are there any attack vectors? How does it compare to the original hash function?

Let's say we want to sign message $M$ with RSA using a safe hash function. However, instead of signing $\operatorname{hash}(M)$, We split the message into 64-bit blocks (|| is concatenation):  $$M = {m_0}||{m_1}||{m_2}||{m_3}\,...$$  For each block we calculate:  $${h_i} = \operatorname{hash}({m_i}||i)$$  and then we calculate the total hash:  $$h = {h_1} \oplus {h_2} \oplus {h_3}\,...$$  and sign $h$ with RSA instead of $\operatorname{hash}(M)$.  Why is it weaker than signing $\operatorname{hash}(M)$?  I know that the order of the blocks cannot be modified because of the concatenation of $i$, and that I cannot add the same block twice because of that too.  I think the answer involves collision, birthday or brute-force attack which may be faster than performing those attacks against $\operatorname{hash}(M)$ but couldn't show that. Any ideas?  P.S: Homework question - hint is enough :)


I have submitted an online application for a Canadian transit visa on 5 July 2018. I am an Indian passport holder and applied from Mumbai. I would like to know when I can expect to get my visa?  Also, as I submitted the application online, do I have to submit my passport physically to get a transit visa stamp?  Thanks in advance.

My question may look similar to another question, but it still doesn't answer my query.  I have submitted the application and still haven't been asked to pay a fee (When I completed the application, it said my total fee is 0 CAD. I'm not sure if it will change in the future.)   Also like I've said, my application has been online. So I can't figure out if I need to submit my passport physically for the transit visa.  ________________________________________________________________________________  I am a student with Indian nationality, currently living in the US.  I am travelling to India in a couple of days and I have a return flight from India to Phoenix, US with a layover in Toronto, Canada. I have learned that I need a transit visa and have applied for one. It says that the average time to process an application is 42 days.  I just want to know the complete procedure that takes place once I submit my application. I scanned all the required documents and have uploaded them while submitting my application.   Do I need to submit my passport to the nearest Canadian consulate? Does the transit visa come by post or is it available in electronic format? What happens if I don't have my transit visa by the time I fly and get to Canada?   Any help and clarification will be most appreciated.


I've posted the same thing in Ubuntu Forums and Steam community but not found a solution. sudo apt update followed by sudo apt upgrade leads to the following: Reading package lists... Done Building dependency tree Reading state information... Done Calculating upgrade... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies. steam:i386 : Conflicts: steam-launcher but 1:1.0.0.64 is to be installed Conflicts: steam-launcher:i386 steam-devices : Conflicts: steam-launcher but 1:1.0.0.64 is to be installed Conflicts: steam-launcher:i386 E: Broken packages   I don't know if there's any connection between the two, but software updater works perfectly fine. Steam also updates upon launch as per usual. When I run sudo apt update I'm told there are 22 packages with requiring upgrades so I'm hopeful of finding a fix. I've also run: sudo apt-get install unattended-upgrades sudo dpkg-reconfigure unattended-upgrades  But nothing happened. Thanks in advance. *Version info - Ubuntu 20.04 LTS and Steam API: v020 Package versions: 1591251555

Occasionally, when I'm installing stuff, I get an error like the following:  Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  package1 : Depends: package2 (>= 1.8) but 1.7.5-1ubuntu1 is to be installed E: Unable to correct problems, you have held broken packages.   How can I resolve this?


Short Introduction  In a classification problem, the objective is to identify to which of a set of categories a new observation belongs, on the basis of a set of examples whose category membership is known.  The bottom-line of any solution to this problem is to find a set of features that describes the classification of the examples into the corresponding categories (hypothesis).  When the size of the set of categories is large, we need more information to distinguish among the different categories (e.g., we could look for more features). Also, if the examples for a particular category have high variance (intra-class variance), it is more difficult to find the discriminant due to the existence of collisions between members of different classes.  Question  I'd like to know if there exists a quick exploratory method to evaluate how difficult a learning problem is. For example, I'd like to evaluate the number of collisions between different categories. The problem of training a classifier and performing some sort of cross-validation is that the solution is dependent on the choice of the learning model.

Almost in all texts which are discussing theorems of statistical learning, they assume analyzing arbitrary unknown distribution (the worst case). But in practice different problems (different data) have different levels of hardness, for example linear separable data is easier to learn than the data that are less (or not) separable by hyperplanes.  Are there any works on formalizing the hardness of data (similar to the stuff done in complexity theory)  Note: I am not sure if the same as analyzing VC-dimension or not, but I think it is not.


My fresh installation of Ubuntu seems to be having an issue detecting eth0. I have tried few things but nothing worked for me.  For example, I have tried what is being advised on this link.   Furthermore, I added these few lines to /etc/network/interfaces   which was originally empty.  auto eth0 iface eth0 inet dhcp   I also tried the following. After downloading the driver from here:   Entering the following commands:  cd e1000e-3.3.5.3/src   Editing nvm.c, function e1000e_validate_nvm_checksum_generic (line 563) to  s32 e1000e_validate_nvm_checksum_generic(struct e1000_hw *hw) {     /*     s32 ret_val;     u16 checksum = 0; u16 i, nvm_data;   for (i = 0; i < (NVM_CHECKSUM_REG + 1); i++) {     ret_val = e1000_read_nvm(hw, i, 1, &nvm_data);     if (ret_val) {         e_dbg("NVM Read Error\n");         return ret_val;     }     checksum += nvm_data; }   if (checksum != (u16)NVM_SUM) {     e_dbg("NVM Checksum Invalid\n");     return -E1000_ERR_NVM; } */       return 0; }   Finally, build and install:  make sudo rmmod e1000e sudo make install sudo modprobe e1000e   Upon entering the command ifconfig, I receive the following  lo        Link encap:Local Loopback             inet addr:127.0.0.1  Mask:255.0.0.0           inet6 addr: ::1/128 Scope:Host           UP LOOPBACK RUNNING  MTU:65536  Metric:1           RX packets:560 errors:0 dropped:0 overruns:0 frame:0           TX packets:560 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000            RX bytes:54167 (54.1 KB)  TX bytes:54167 (54.1 KB)  wlp3s0    Link encap:Ethernet  HWaddr a4:34:d9:92:f1:58             inet addr:192.168.1.82  Bcast:192.168.1.255  Mask:255.255.255.0           inet6 addr: 2602:306:3a54:4190:b664:4bd6:984d:dd39/64 Scope:Global           inet6 addr: fe80::f960:171e:a497:f047/64 Scope:Link           inet6 addr: 2602:306:3a54:4190:cba:bd01:e6fd:411c/64 Scope:Global           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1           RX packets:2141 errors:0 dropped:0 overruns:0 frame:0           TX packets:1230 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000    Upon entering the command inxi -SNxz, I receive the following:  System:    Host: abdu-Default-string Kernel: 4.13.0-36-generic x86_64 (64 bit gcc: 5.4.0)            Desktop: Unity 7.4.0 (Gtk 3.18.9) Distro: Ubuntu 16.04 xenial Network:   Card-1: Intel Ethernet Connection (2) I219-V bus-ID: 00:1f.6            Card-2: Intel Wireless 8260 driver: iwlwifi bus-ID: 03:00.0   So the card is being detected but cannot be used for some reason.  The output for ip link  1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: wlp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DORMANT group default qlen 1000     link/ether a4:34:d9:92:f1:58 brd ff:ff:ff:ff:ff:ff   Problem solved by following the instruction on this link:   Any help is appreciated.

I have a problem with an : when I boot it with Ubuntu 16.04 (or NixOS 16.03) the Ethernet port does not work.  The driver used is , it reports:  $ dmesg | grep e1000e [    5.643760] e1000e: Intel(R) PRO/1000 Network Driver - 3.2.6-k [    5.643761] e1000e: Copyright(c) 1999 - 2015 Intel Corporation. [    5.644308] e1000e 0000:00:1f.6: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode [    5.877838] e1000e 0000:00:1f.6: The NVM Checksum Is Not Valid [    5.907340] e1000e: probe of 0000:00:1f.6 failed with error -5   Under Windows 7 Ethernet port works fine: I can connect to the Internet. According to Windows, I have .  I have searched for "official" , but none is listed as supporting I219-V.  However, e1000e is listed as supporting I218-V, and I've got a confirmation from  mailing list that e1000e should support I219-V.  Just in case I tried using the latest version 3.3.4 of e1000e, but the error was the same: "The NVM Checksum Is Not Valid."  It looks like indeed there is a mismatch of the checksum of the non-volatile memory of I219-V.  I have tried another ASUS laptop of the same model, and the error was the same, so this does not look like an accidental corruption.  Neither ASUS nor Intel customer support could suggest any solution.  I have discovered , but according to the  (for version 1.6.13.0) it is only intended for PCI, not OEM on-board, Ethernet cards.  However, I decided to run it without parameters just to print the list of Intel network ports, and this is what I've got:  $ sudo ./bootutil64e  Intel(R) Ethernet Flash Firmware Utility BootUtil version 1.6.13.0 Copyright (C) 2003-2016 Intel Corporation  Type BootUtil -? for help  Port Network Address Location Series  WOL Flash Firmware                Version ==== =============== ======== ======= === ============================= =======   1   D017C2201F59     0:31.6 Gigabit N/A FLASH Not Present   I do not quite understand what "FLASH Not Present" means here.  I posed a  on SuperUser.SE about fixing the NVM checksum. Here I am asking if and how anyone managed to successfully install Linux with working Ethernet on an ASUSPRO B8430UA laptop or on any other laptops with Intel Ethernet Controllers which had "The NVM Checksum Is Not Valid" error.


Just installed Ubuntu 14.04.1 on a Dell 755.     Trying to install the above adapter. lsusb lists it as;  Bus 001 Device 004: ID 148f:760b Ralink Technology, Corp.   Any instructions I have found to get this chipset (MT7601UM) do not work.   Any help on this would be greatly appreciated! I bought 8 of these and they work great on Win 7. Just can't get it to run on Ubuntu or Zorin.

I am trying to install a Ralink wifi adapter in Ubuntu Desktop 14.04.  The system is not detecting the wifi.   lsusb lists the device as:  Bus 002 Device 004: ID 148f:7601 Ralink Technology, Corp.  I have the rt2800 USB driver listed in "/etc/modules"; Following some instructions on the web, I tried this command:  echo 148F 7601 | sudo tee /sys/bus/usb/drivers/rt2800usb/new_i  lsmod | grep rt2800 returns the following:  rt2800usb              26581  0  rt2x00usb              20041  1 rt2800usb rt2800lib              83150  1 rt2800usb rt2x00lib              48886  3 rt2x00usb,rt2800lib,rt2800usb mac80211              545990  3 rt2x00lib,rt2x00usb,rt2800lib crc_ccitt              12627  1 rt2800lib


I have two hard disks in my PC (160 GB & 80 GB). The 160 GB hard disk has Ubuntu 12.04 installed in it while the 80 GB hard disk has Windows XP. I added the 80 GB hard disk just a few days ago, before which I was using only the hard disk with Ubuntu.   Before the addition of the second hard disk, the Time & Date settings worked fine in Ubuntu(It showed the correct time and date every time I booted my PC). But now, whenever I boot my system, the time is wrong. Even if I set it correctly it becomes wrong the next time I boot my PC.  What is causing this problem and how can I resolve it?

Today I was installing Windows 7 on the same computer I have Ubuntu. For some reason, after installing Windows 7 and going back to Ubuntu the time went from the correct hour at that moment, 12:30PM to 7:30AM. This happened after installing Windows 7. For what I understand the BIOS has a time set, Ubuntu has the same time that is shown in the BIOS when installing it. At least up to this point is what I have seen. Now after installing Windows 7 (And believe me this is only for testing the performance of Windows 7 against Ubuntu in which case Windows 7 is falling behind a lot on the same hardware) the time changes in Ubuntu to the wrong one that is set in Windows 7.  I actually do not change the time in Windows 7 since this is one of the checks I am doing to see if the operating system can correctly grab the time. Windows 7 fails. Ubuntu does not BUT Windows 7 actually changes the time for Ubuntu if I boot with it afterwards.  So my question is, why/how does time change in Ubuntu after installing Windows.  NOTE - I have set Ubuntu time to "manual" instead of grabbing it from the Internet just to test out this.


I created a new non-root user and did the following:  useradd -m newusername  passwd newusername  usermod -a -G sudo newusername  chsh -s /bin/bash newusername    I need to install software as a non-root user, but when I'm logged in as that user,   cd Downloads   does nothing. The directory doesn't exist. Did I do something wrong when creating the user, or am I missing something?  cd /home/newusername/Downloads   does not work either.

How do I do this? I created a user without a home directory and now I want to create one. Not just a folder called new_user, I want the default home directory with all it's folders and hidden files, etc.


How would one go about proving the following identities?  $$\sum_{i=1}^n \sum_{i\neq j}^n \frac{z_i}{z_i-z_j} = \frac{n(n-1)}{2}$$ $$\sum_{i=1}^n \sum_{i\neq j}^n \frac{z_i^2}{z_i-z_j} = (n-1)\sum_{i=1}^n z_i$$ $$\sum_{i=1}^n \sum_{i\neq j}^n \frac{z_i^3}{z_i-z_j} = (n-1)\sum_{i=j}^n z_i^2+\sum_{i<j}^n z_i z_j$$ $$\sum_{i=1}^n \sum_{i\neq j}^n \frac{z_i^4}{z_i-z_j} = (n-1)\sum_{i=j}^n z_i^3+\sum_{i<j}^n z_i z_j(z_i+z_j)$$ $$\sum_{i=1}^n \sum_{i\neq j}^n \frac{z_i^5}{z_i-z_j} = (n-1)\sum_{i=j}^n z_i^4+\sum_{i<j}^n z_i z_j(z_i^2+z_i z_j +z_j^2)$$  I see the obvious pattern here. The problem is that the algebra involving the summation is giving me some difficulty.

I've been reading a research paper, and I'm interested in generalizing a certain theorem but I can't seem to understand how the following results are derived:  $$\sum_{i=1}^{n}\sum_{j\neq i}^n \frac{1}{z_i-z_j}=0$$  $$\sum_{i=1}^{n}\sum_{j\neq i}^n \frac{z_i}{z_i-z_j}=\frac{1}{2}n(n-1)$$ $$\sum_{i=1}^{n}\sum_{j\neq i}^n \frac{z_i^2}{z_i-z_j}=(n-1)\sum_{i=1}^n z_i$$ $$\sum_{i=1}^{n}\sum_{j\neq i}^n \frac{z_i^3}{z_i-z_j}=(n-1)\sum_{i=1}^n z_i^2 + \sum_{i<j}^n z_i z_j$$


Disclamer: the question i am asking is what determines what linux distro i'm using not "am i still useing ubuntu" now for the question. I use to think that a linux distro was defined by its desktop environment, but now I have 7 desktop environments. Am I still useing ubuntu? Have I made a ubuntu dirivitive? I know some distros have difrent ways you install stuff like debien & ubuntu use apt-get, & arch uses pacman. So what i'm asking is what determins which linux distro you are useing?

I installed Cinnamon on my Ubuntu OS.  Am I still using Ubuntu or Linux Mint when I use the Cinnamon desktop environment?


I was wondering if there is a general way to solve the functional equation  $$(\exists k)(f^\prime(x) = f(x+k))$$  I know that this is true for certain functions:  $$(e^{cx})^\prime = e^{c(x+\frac{\ln c}{c})}$$ $$\sin(x)^\prime=\sin(x+\tfrac{\pi}{2})$$  but I was wondering if these functions take a general form or are related to the eigenvalues of the second derivative, because both of these are.

Are exponential & trigonometric functions the only non-trivial solutions to $F'(x)=F(x+a)$?   $F(x)=0$ would be the trivial solution. Then, for $a=0$ (or  $a=2\pi i$), we have $F(x)=e^x$, and for $a=\dfrac\pi2$ there are $F(x)=\sin x$ and $F(x)=\cos x$. But the three are connected by  $e^{ix}=\cos x$ $+i\sin x$. Indeed, on a more  note, letting $F(x)=e^{\lambda x}$, we have $\lambda=\dfrac{W(-a)}{-a}$ where W is the . My question would be if these are the only ones, due to the special properties of the number e and the exponential function, or if there aren't by any chance more, which do not belong in the same family or category as these, i.e., which are not exponential or trigonometric in nature ? Thank you.


Find all number $n\in \mathbb N$ such that $\varphi (n)=14$   $\varphi (n)=p_1^{\alpha_1-1}\cdot p_2^{\alpha_2-1}\cdots p_n^{\alpha_n-1}(p_1-1)\cdots (p_n-1)=14$ so number that divide 14 $x|14$ is $x\in \{1,2,7,14\}$ so $p_i-1=1$ or $p_i-1=2$ or $p_i-1=7$ or $p_i-1=14$ $i\in \{1,2,\ldots n \}$ so $p_i=2, p_i=3, p_i=8, p_i=15$ since $8,15$ is not prime number then $p\in \{2,3\}$.  If we say that $n=2^{\alpha}$ then $\varphi (n)=2^{\alpha-1}=14$ so there is not such $\alpha \in \mathbb N$ that $\varphi(n)=14$ so $n\not=2^{\alpha}$  The same is for $n=3^{\beta}$ and $ n=2^{\alpha}\cdot 3^{\beta}$. So there is not exist $n\in \mathbb N$ such that $\varphi(n)=14$  Is this ok?

I did the following proof and I was wondering if its valid. It feels wrong because I didn't actually test the case when purportedly $n$ is not prime, but please feel free to correct me.  Assume there exists $n$ such that $\phi(n) = 14$. Assume $n$ is prime. Then $\phi(n) = n-1$. Then here, n-1 = 14, so n = 15.  We know since Euler's totient function is multiplicative that $\phi(xy)$ = $\phi(x)\phi(y)$, so $\phi(15) = \phi(3)\phi(5)$, but alas $\phi(3)\phi(5) = 2\cdot4 = 8 \ne 14$. If $n$ is not prime a similar argument follows since we know then that $n$ must be composed of prime numbers by the prime factorization theorem.


I have (I think) a standard sleep / turn off display settings in my Windows 10:    Yet my computer turns off display after 30 seconds since locking the computer.  If I lock computer manually, display's power is cut-off (display is turned off) after just 30 seconds since lock / stop of work. If I stop the work, but do not lock the computer then Windows locks it up after two minutes and then turns off the display after another 30 seconds.  To summarize: My display is never turned of after 15 minutes, despite above settings, it lasts turned on for between 30 seconds and 150 seconds at most.  How can I control when my display for locked computer is turned off, or how can I enforce that my display will always be turned of -- as set / said -- after 15 minutes and not even a second earlier?  Edit: I went through all advanced power settings etc., all for nothing -- everything I look or check, I can clearly see the same setting -- 15 minutes. I must be looking in an incorrect place, though.

I have my PC connected to a TV, because it's significantly cheaper than the same screen with "computer display" label.  To make us regret for the money saved, manufacturers of both types of devices ensured, that TVs should not turn off when no input signal. They use to display very bright, ugly and annoying screen "no signal" and eventually, they would turn off after minimum of 15 or 30 minutes.  However, Windows 10 lock screen turns the screen off like in a minute. Then it requires one click to "wake up", another click to activate pin or password input. It looks bad, it's annoying. BTW, what's the point in choosing lock screen background picture if it's hardly shown?  So I'm looking for the way to change power management settings for the lock screen. It's different form user settings.  It is NOT in Lock Screen Settings (where I would expect it). There is even an option "Screen timeout settings", but it is set to 1 hour. The screen is turned off after like 1 minute, not 1 hour, so it doesn't work. 1 hour is my user setting, it's works when I'm signed in to my desktop.


Are there any $n \times n$ $(n \ne 1)$ matrices satisfying $$Det(A+B)=Det(A)+Det(B)$$  Trivially the above equation is True for either $A=O$ or $B=O$ or $ A=B=O$  For $2 \times 2$ matrix i have tried  as follows:  Let $$A=\begin{bmatrix} a &b \\  c & d \end{bmatrix}$$  and $$B=\begin{bmatrix} p &q \\  r &s \end{bmatrix}$$  Then we have  $$Det(A+B)=(a+p)(d+s)-(b+q)(c+r)$$  $$Det(A)+Det(B)=ad-bc+ps-rq$$  Equating both we get  $$as+pd=br+qc$$  which is satisfied by infinite values of $a,b,c,d,p,q,r,s$   One such pair is  $$A=\begin{bmatrix} 2 &10 \\  2 & 3 \end{bmatrix} $$ and  $$B=\begin{bmatrix} 4 &1 \\  2 &5 \end{bmatrix}$$  is there any general way to find the matrices of higher order?

Well considering two $n \times n$ matrices does the following hold true: $$\det(A+B) = \det(A) + \det(B)$$ Can there be said anything about $\det(A+B)$?  If $A/B$ are symmetric (or maybe even of the form $\lambda I$) - can then things be said?


Let $f$ be a continuous function on a set $I\subset \mathbb{R}$. Does there always exist a function $F$ differentiable on an open set $J$ containing $I$ such that $F'=f$ on $I$ ?  The case where J is an interval has been studied in this thread

Let $f$ be a continuous function on a part $I$ of $\mathbb{R}$. Is they exist always a function $F$ differentiable on an interval $J$ containing I such that $F'=f$ on $I$?  If $I$ is an interval , it's ok  if $I$ is an open set , it's ok  But if $I$ is only a part of $\mathbb{R}$  ?


Which one is correct? Am I working in or at a bank?

What are the main purposes to ask someone 'Where do you work?' apart from to find out the type of place he or she works in?  I can answer:     I work in a shop.   I work in a hospital.   I work in an office.   But what other things can (or should) I use as a reply to this question?    Extra question:  sometimes I see     I work at a shop.    I work at a hospital.    I work at an office.   What's the difference between 'at' and 'in' in this case?


I want to export an FBX with textures. How do I do it? All I get is the model without textures. Please explain with as much detail as possible. Basically I want to convert an GLB into FBX with textures because Unity doesn't like GLB.

I created a interior scene and  i don't know how to bake a texture using cycles bake.


At  on field automorphisms by Professor Macauley, the proof that an automorphism, $\phi,$ on an extension field $F$ of $\mathbb Q$ fixes the rational numbers, i.e.  $$\phi(q)=q\quad\quad\quad  \forall \; q \in \mathbb Q$$  is given for the number $1,$ asserting that if $\phi(1)=q,$ $q$ can't be $0$ since, if it were,  $$\phi(2)=\phi(1+1)=\phi(1)+\phi(1)=0$$  and $\phi(\dot)$ would not be a bijection.  Likewise, since  $$q=\phi(1)=\phi(1\cdot1)=\phi(1)\cdot\phi(1)=q^2$$  and  $$q=\phi(1)=\phi(1\cdot1\cdot 1)=\phi(1)\cdot\phi(1)\cdot\phi(1)=q^3$$  we have to conclude that $\phi(1)=1.$  This is clear, but the question is      How does this proof generalize to the rest of rational numbers    $$\phi(n)=n;\;n>1,n=\frac{a}{b}; \, a,b\in \mathbb Q?$$

Let $\mathbb \phi $ be an automorphism of the group of rational numbers $\mathbb \ Q$ under addition.  Prove that $\mathbb \phi(x)=x \phi(1), \forall x \in Q. $


Data, Lore, and B4 all have yellow eyes and white metal exoskeletons. Why did Noonien Soong give them yellow eyes instead of blue or something natural? The Androids were supposed to be as human looking as possible but I don't see many people with yellow eyes. Wouldn't they have had a solution for their eye color and exoskeleton to appear more human in the future? In the TOS episode I Mudd, the Androids had a human exoskeleton color and normal eyes and that is earlier than TNG. Brent Spiner told a story of him asking Gene Roddenberry why did he have to have a different skin color but the answer he gave didn't really suffice.

Was there any reason why Dr Soong chose for Data's eyes to be yellow?  I can understand that he wasn't going for a completely human-looking android based on his skin color, but why yellow eyes?


How can I build a C compiler while offline? I have downloaded and transfered bison, make, build-utils, and dpkg yet without a gcc in this distro what can I do?

I have a friend who has got a computer that is not connected to the Internet. Is there any way to install software offline easily?


I'm struggling trying to prove $[\overrightarrow{x}, f(\overrightarrow{p})]= i\hbar\frac{\partial f(\overrightarrow{p})}{\partial \overrightarrow{p}}$. I already proved that $[x_i,p_i^n]=i\hbar \frac{\partial p_i^n}{\partial p_i}$ and I need to express $f$ in a power series but I don't know how to do that and derive the result. Can someone help me?

indicates that the following relation is "easily shown": $[x_i, F(\vec p)] = i \hbar \frac {\partial F(\vec p)}{\partial p_i}$, however I'm having some trouble showing it.  I think I'm just messing up the multivariable Taylor expansion (of $F(\vec p)$).  Can one of you walk me through it or link me to site that will?  Thanks.  Edit: Here's what I get (without using $x=i\hbar \frac \partial {\partial p}$ which I haven't proven yet): $$F(\vec p) = F(\vec 0) + \sum^3_{j=1} \frac {\partial F(\vec 0)}{\partial p_j}p_j + \frac 12 \sum^3_{k=1} \sum^3_{j=1} \frac {\partial^2 F(\vec 0)}{\partial p_k \partial p_j} p_j p_k + \dots$$ so $$(x_iF(\vec p) - F(\vec p)x_i)\psi$$ $$= x_i[F(\vec 0)\psi -i\hbar \sum^3_{j=1} \frac {\partial F(\vec 0)}{\partial p_j}(\nabla \psi)_j + \hbar^2\frac 12 \sum^3_{k=1} \sum^3_{j=1} \frac {\partial^2 F(\vec 0)}{\partial p_k \partial p_j} (\nabla \psi)_j (\nabla \psi)_k + \dots]$$ $$- [F(\vec 0)x_i\psi -i\hbar \sum^3_{j=1} \frac {\partial F(\vec 0)}{\partial p_j}(\nabla x_i\psi)_j + \hbar^2\frac 12 \sum^3_{k=1} \sum^3_{j=1} \frac {\partial^2 F(\vec 0)}{\partial p_k \partial p_j} (\nabla x_i\psi)_j (\nabla x_i\psi)_k + \dots]$$ where $$(\nabla x_i\psi)_j=\frac {\partial x_i}{\partial x_j}\psi + x_i\frac {\partial \psi}{\partial x_j} = \delta_{ij}\psi + x_i\frac {\partial \psi}{\partial x_j}$$ and $$(\nabla x_i\psi)_j(\nabla x_i\psi)_k=(\delta_{ij}\psi + x_i\frac {\partial \psi}{\partial x_j})(\delta_{ik}\psi + x_i\frac {\partial \psi}{\partial x_k}) = \delta_{jk}\psi^2 + x_j \psi \frac {\partial \psi}{\partial x_k} + x_k \frac {\partial \psi}{\partial x_j} \psi + x_i^2 \frac {\partial^2 \psi}{\partial x_j \partial x_k}$$ Thus: $$(x_iF(\vec p) - F(\vec p)x_i)\psi$$ $$=  x_i[F(\vec 0)\psi -i\hbar \sum^3_{j=1} \frac {\partial F(\vec 0)}{\partial p_j}\frac {\partial \psi}{\partial x_j} + \hbar^2\frac 12 \sum^3_{k=1} \sum^3_{j=1} \frac {\partial^2 F(\vec 0)}{\partial p_k \partial p_j} \frac {\partial \psi}{\partial x_j} \frac {\partial \psi}{\partial x_k} + \dots]$$ $$- [F(\vec 0)x_i\psi -i\hbar \sum^3_{j=1} \frac {\partial F(\vec 0)}{\partial p_j}(\delta_{ij}\psi + x_i\frac {\partial \psi}{\partial x_j}) + \hbar^2\frac 12 \sum^3_{k=1} \sum^3_{j=1} \frac {\partial^2 F(\vec 0)}{\partial p_k \partial p_j} (\delta_{jk}\psi^2 + x_j \psi \frac {\partial \psi}{\partial x_k} + x_k \frac {\partial \psi}{\partial x_j} \psi + x_i^2 \frac {\partial^2 \psi}{\partial x_j \partial x_k}) + \dots]$$ From here it doesn't look like those higher order terms are all going to cancel out.


I've written a static extension method that acts on an int, but I'd like to make it more robust to act on any , such as ushort or char. Is there any way to do this, short of code duplication?  Right now my method signature looks something like this:  public static class ExtensionMethods {     public static T MyCoolMethod<T>(this int value) where T : struct, IConvertible     {         ...     } }   Can I swap out int for some common interface, or do something else with generics to get it so this extension method can apply to any integral type?

Can anyone tell me if there is a way with generics to limit a generic type argument T to only:   Int16 Int32 Int64 UInt16 UInt32 UInt64   I'm aware of the where keyword, but can't find an interface for only these types,  Something like:  static bool IntegerFunction<T>(T value) where T : INumeric


I read about the derivative of the absolute value |x|, but why the absolute value is not differentiable at point zero, and when it becomes 1 or -1 {geometrically}?  Thanks

Okay, so $\displaystyle \frac{d}{dx} |x| = \frac{|x|}{x}$. But I have trouble seeing why.  Here's what I've tried: $$\frac{d}{dx}|x|=\begin{cases} \frac{d}{dx}x & \text{if }x > 0 \\ \frac{d}{dx}(-x)&\text{if }x < 0 \end{cases} = \begin{cases} \,\,\,\,1 & \text{if }x > 0 \\ -1&\text{if }x < 0 \end{cases}$$ But I do not see how that far-right expression can be used to arrive at $\displaystyle\frac{|x|}{x}$, besides graphing.


I have Ubuntu 14.04 installed on my Windows 7 PC using wubi. The system does not boot and I'm trying to mount root.disk file in order to restart it from a Ubuntu live USB. But terminal shows me:  mount: Stale file handle   I have no idea what it means, nor how can I solve it. Any idea?  The commands that I used were:  sudo mkdir /media/win7ub sudo mkdir /media/ubuntu1404 sudo mount -t ntfs /dev/sda3 /media/win7ub sudo mount -t ext4 -o loop /media/win7ub/ubuntu/disks.root.disk /media/ubuntu1404   I run WIndows 7 professional and my PC does not support UEFI. I installed WUBI 12.10

I would like to see a full how-to guide on how to install Ubuntu.


Is it correct to say "1 feet 1 inches"?  shows examples of such expressions. They might have been erroneously automatically generated, though. Notes: I'm not sure who would ever think this is a duplicate, but I just want to say that this question is, if anything, the opposite of what it's supposedly the duplicate of. There's no such question as "Why don't we pluralize “foot” in measurements?" here; I ask if it's correct to say "1 feet 1 inches" and that's it. Logically, I would assume that you don't say either "1 feet" or "1 inches" because those seem ungrammatical at the very least.

For example, to answer the question, "How tall are you?" valid answers include:   Five feet. Five foot three. Five feet, three inches.   Why the discrepancy between feet and foot, seemingly only in the second case.    This question is inspired by this question:   edit: I do not believe the answer to this is related to the other question. The explanation for the other question is because of how adjective modifiers work. My question is a very different case, unrelated to adjectives. My observation is that I am asking about a particular exception case which applies only when "foot" is followed by a number which is assumed to be inches. That's extremely specific, and I doubt that the etymology has any relation to why we leave adjective modifiers singular.


I'm trying to run "loadProgram" located in the motherboard class through the "Room" class.  I typed   theRoom.getTheComputer().getMotherboard().loadProgram("Windows"); But I get   Exception in thread "main" java.lang.NullPointerException     at Main.main(Main.java:12)<5 internal calls>  Main   public class Main {     public static void main(String[] args) {       Keyboard theKeyboard = new Keyboard("Test1", "Razer");     Motherboard theMotherboard = new Motherboard("RX-58","Asus",4, 6, "v2.44");      Computer theComputer = new Computer(theKeyboard, theMotherboard);     Room theRoom = new Room(theComputer);      theRoom.getTheComputer().getMotherboard().loadProgram("Windows");    } }   Room  public class Room {  private Computer theComputer;  public Room(Computer theComputer) {     this.theComputer = theComputer; }  public Computer getTheComputer() {     return theComputer; } }   Computer  public class Computer { private Keyboard theKeyboard; private Motherboard motherboard;  public Computer(Keyboard theKeyboard, Motherboard theMotherboard) {     this.theKeyboard = theKeyboard; }  public Keyboard getTheKeyboard() {     return theKeyboard; }  public Motherboard getMotherboard(){     return motherboard; } }   Motherboard  public class Motherboard {  private String model; private String manufacturer; private int ramSlots; private int cardSlots; private String bios;  public Motherboard(String model, String manufacturer, int ramSlots, int cardSlots, String bios) {     this.model = model;     this.manufacturer = manufacturer;     this.ramSlots = ramSlots;     this.cardSlots = cardSlots;     this.bios = bios; }   public void loadProgram(String programName){     System.out.println("Program " + programName + " Is now loading... " ); }  public String getModel() {     return model; }  public String getManufacturer() {     return manufacturer; }  public int getRamSlots() {     return ramSlots; }  public int getCardSlots() {     return cardSlots; }  public String getBios() {     return bios; }   }

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


I already read this question:  but it doesn't answer mine.  It seems to me, that the wildcards (especially *) are not consistently working correctly.  Assume I have a file with the name abc_d270_def_1000.fun. When I search in the Windows 8 Explorer for *000.fun, it doesn't find this file. But in Windows 7 the exact same search string does find this file. I did a bit of investigation and discovered that my file won't be found when I'm searching for  abc_d*70_def_1000.fun abc_d**0_def_1000.fun   but it will be found when I'm searching for  abc_d***_def_1000.fun abc_d2**_def_1000.fun abc_d27*_def_1000.fun   So it seems that the wildcards can not be placed before a number.  Is there a way to change this, so that I can search for *000.fun and my file will get found?

I have a bunch of PDF documents in a network folder that follow a similar file name structure:  CompanyName - $160.99.pdf  When I open the folder containing all the documents in Windows 7, I can search by the CompanyName, but not by the dollar amount. The search just simply shows no results when searching by dollar amount. It shows perfect results when I search by company name.  I've tried searching both with and without the dollar ($) sign, but no change. As in the above example, I would get nothing if I searched for 160.99 or $160.99.  I've searched high and low but I've found nothing similar or people with the same problem.  Any idea what would cause this behavior?


import java.util.Scanner; public class RandomTest {  public static void main(String[] args) {     Scanner input=new Scanner(System.in);     String[] alphabets={"a","b"};     String [] cipher={"b","c"};     System.out.println("Please enter a letter.");                 String word=input.nextLine();      for (int i=0;i<2;i++){         if (word.equals(alphabets[i])){             System.out.println("Preparing a cipher");             System.out.println("Here is the cipher: "+cipher[i]);              }     } } }   This code above works perfectly fine, but instead of saying (word.equals(alphabets[i])), if i put word==alphabets[i] it wouldn't work at all. While using the later, the program does not check if the input is equal to a value in the array. Why does this happen?

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


I'm trying to modify a file from /etc/ but I can't, because the file I want to modify require root permission and I accidentally erase it.   I tried to use some sudo commands but I can't because every time i get   unknown user : root

I can't seem to edit and save config files in the root system (eg: /etc/dhcp/dhcpd.config); it just says "permission denied" or the save option is blocked in the text editor.  I'm pretty sure I'm a root user, but how do I make sure? If I am a root user, how do I fix this?


On Ubuntu 12.10 when trying   sudo apt-get install mono-complete   to install mono, I get:  enter codReading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  mono-complete : Depends: mono-devel (= 2.10.8.1-5ubuntu1) but it is not going to be installed                  Depends: libmono-cil-dev (= 2.10.8.1-5ubuntu1) but it is not going to be installed E: Unable to correct problems, you have held broken packages.   I tried removing mono-devel and libmono-cil-dev but they are not installed.  I've tried   sudo apt-get clean && apt-get update && apt-get upgrade   but it does not help.   dpkg --get-selections | grep hold   does not give any results, so it seems that no packages are actually held.  I've also tried  dpkg --configure -a   and   apt-get install -f   neither of which helped either.  Strangely though, I do have mono installed in /usr/bin/mono. The way that I got into this mess was that I tried to get the latest versions by following the directions here: . apt-get was complaining about held packages at which point I did   sudo apt-get dist-upgrade   I don't know if that was the cause of my current problems. Anyway, after it continued to complain about packages being held, I removed that experimental mono deb source from my sources and removed mono-complete, and ran apt-get clean, update, and upgrade, to get back the blank slate. At that point, I tried to install mono-complete from a blank slate, and arrived to my current situation.  EDIT:  $ apt-cache policy mono-devel libmono-cil-dev mono-devel:   Installed: (none)   Candidate: 2.10.8.1-5ubuntu1   Version table:      2.10.8.1-5ubuntu1 0         500 http://us.archive.ubuntu.com/ubuntu/ quantal/main i386 Packages         100 /var/lib/dpkg/status libmono-cil-dev:   Installed: (none)   Candidate: 2.10.8.1-5ubuntu1   Version table:      2.10.8.1-5ubuntu1 0         500 http://us.archive.ubuntu.com/ubuntu/ quantal/main i386 Packages   @meebey of the linked experimental page recommends apt-get remove cli-common for a full mono removal which outputs this:  Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  mono-xsp4 : Depends: mono-xsp4-base (= 2.10-2.1) but it is not going to be installed E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.   RESOLVED I resolved this issue by adding the experimental ppa back and removed mono-complete and cli-common. Then I removed the experimental ppa again which got me back to a blank slate. For that reason I don't consider this a duplicate issue, but it doesn't matter.

Occasionally, when I'm installing stuff, I get an error like the following:  Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  package1 : Depends: package2 (>= 1.8) but 1.7.5-1ubuntu1 is to be installed E: Unable to correct problems, you have held broken packages.   How can I resolve this?


Is there a way to discover if an installed OS is workstation or server? Is it just a matter of the packages that are installed or is there some difference that can be detected?

I have a shared hosting. I have access to shell. The OS is Ubuntu, and I want to check whether it is the server version or desktop version.  When I log in through shell, it shows following information:  Linux [server-name] 2.6.32-24-generic #39-Ubuntu SMP Wed Jul 28 06:07:29 UTC 2010 i686 GNU/Linux Ubuntu 10.04.1 LTS


I have saved a HTML web page. I got a .html file along with a folder which has the same name. Both of these seem to be linked magically:   if I delete the HTML file, the folder gets deleted as well if I delete the folder, the HTML file gets deleted as well   The question is 2-fold:   how do I delete the folder without deleting the HTML file? how does that technically work? How does Windows or NTFS perform the necessary linking?   I'm on Windows 7 SP1 x64, all updates. The files were saved using Firefox 61.0.1. However, on the disk, it's shown as a "Chrome HTML Document".

When you right-click save-as a web page in FF, the page is saved along with a folder containing any associated media that page needs (images, js, etc).  My problem is that I want to reorganise the associated media folder, but wherever I move this folder, the saved .html file is moved as well. ARGH!   I can rename each folder, which breaks the "link" between html file and media folder, but there must be a cleaner way to do it. Does anyone else know?


After the update today I get the error message: File `tikz.sty' not found. There must be a problem with the latest version of MiKTeX 2.9.

I use Texstudio and Miktex on Win 7 as a portable version.  Today i updated my miktex-packages and everything worked fine except the "\usepackage{tikz}" command.  I made a fresh reinstall with the newest versions of miktex and texstudio, opened my latex-document and compiled it. Miktex installed all missing packages on-the-fly except pgf/tikz, wich gave an error instead. I installed it manually in the package manager but texstudio still says "File "tikz.sty" not found".  Unfortunately I have to use the portable version, because I don't have any admin rights. The last time I worked on that document, everything worked fine.  Any ideas?


I'm working on a website with 100s of locations. There is a location search page (Find Widget Dealer), a page for each state (Tennessee Widget Dealers) and finally a page for each individual location which has localized unique content and contact info (Nashville Widget Dealer). My question is is related to how I should structure my URL and the keywords within the URL. Keywords in my examples being the location and the product (i.e. widget).  Here is a quick overview of each of the 3 tiered pages, with the Nashville page being the most optimized:   Find Widget Dealer: Dealer Page only includes a location search bar and bullet list links to states Tennessee Widget Dealers: Page includes brief unique content for the the state and basic listing info for each location along with links to the local page) Nashville Widget Dealer: Page includes a good amount of unique content for this specific location (Most optimized page)   That said, here are the 3 URL structure options I am considering:   domain/widget-dealers/tennesee/nashville domain/dealers/tennesee-widget-dealers/nashville domain/dealers/tennesee/nashville-widget-dealer   Any help is appreciated! Thank you

I'm working for a website to convert the website URL to an SEO friendly URL. I plan to use this:  example.com/category-name/pageid-123-page-name  I looked at some similarly categorized, highly ranked websites. They have the same structure, except for one thing. In one case, the URL format was  example.com/category-name/pageid-123-page-name.html  Another was   example.com/category-name/pageid-123-page-name.php  Now I know the text in URLs help with SEO. Is it more helpful to have a file extension? If yes, which one is better?  Or if my current plan is okay, will it be better with a / at the end?


The moon's orbital radius is fixed as a function of its velocity (I know it is actually drifting..).  Since there is nothing in space to resist this velocity, it will continue orbiting "forever".  Now the earth has water.  As the moon orbits the earth (forever) its gravity pulls on the water causing work to be done moving the water around the earth's surface.  Moving this water doesn't cause the moon's orbital velocity to reduce.  Nor does the moon's mass change.  Nor does the moon appear to lose any energy as a result.  If the moon orbits the earth for eternity does it do work for eternity for free?  Where does the energy come from to continuously move water around the earth's surface?

Kind of an odd, random question that popped into my head. Tidal energy - earth's ocean movement, volcanism on some of Jupiter's moons, etc. - obviously comes from the gravitational interaction between large bodies. On earth the interactions with the moon are pulling water around the surface, creating some amount of heat due to friction, etc.   My question is, where does that energy come from exactly? More specifically, what potential energy source is getting depleted to do that work? Is the earth minutely slowing down in its spin - or are the orbits of earth and the moon subtly altered over time by the counteractive movement and friction of liquids and gasses?


I recently moved from having a main site like www.example.com with a subdomain associated site yyy.example.com, to moving everything off the subdomain to a subdirectory like www.example.com/yyy/, with the same hierarchy underneath the subdirectory, and now yyy.example.com is just a redirect page to the subdirectory, so yyy.example.com/abc/page-x is redirected to www.example.com/yyy/abc/page-x and so on.  The effect has been that the traffic increased by several times (the total page views are more than ten times at the present rate) what it was to the yyy subdomain. Previously almost all of the traffic to the yyy subdomain was from the www site. This is from monitoring the old yyy site for a year or more.  I'm curious to know if there's any research or results which would indicate whether this is universal (subdirectories beat subdomains) or "just me".

If I have example.com, and blog.example.com, do search engines see those as one site or two? Will using subdomains hurt SEO? I have some technical reasons why I can't use example.com/blog.


I was going through a document of Western Michigan University to understand the limitations of K-means clustering algorithms. Below is the link:  On slide no 33 its mentioned that K-means has problems when clusters are of different  Sizes Densities Non globular shapes  Since we explore our data and try to figure out the different groups that are present in our data through the k-means clustering algorithm, how would we know that the size of the clusters is different beforehand? We can visualize it if we have two-dimensional data but how it can be done if the data is n-dimensional? Is there any way to examine the data before proceeding to apply k-means. Also, the explanation for the limitation is: if we have different sizes of clusters, k-means will not give the desirable clusters as it tries to partition the clusters equally. But I don't think its always the case. I had applied k-means on the following dataset with k-means++ initialization  It gave me clusters with highly uneven distribution of 4346, 23, 3. I think I am missing some prerequisite steps before proceeding. Please help me clear my doubts. Thanks.

K-means is a widely used method in cluster analysis. In my understanding, this method does NOT require ANY assumptions, i.e., give me a dataset and a pre-specified number of clusters, k, and I just apply this algorithm which minimizes the sum of squared errors (SSE), the within cluster squared error.  So k-means is essentially an optimization problem.  I read some material about the drawbacks of k-means.  Most of them say that:   k-means assumes the variance of the distribution of each attribute (variable) is spherical;  all variables have the same variance; the prior probability for all k clusters is the same, i.e., each cluster has roughly equal number of observations;   If any one of these 3 assumptions are violated, then k-means will fail.  I could not understand the logic behind this statement. I think the k-means method makes essentially no assumptions, it just minimizes the SSE, so I cannot see the link between minimizing the SSE and those 3 "assumptions".


I want to understand the process of how your domain gets queried from dns servers after purchasing a domain. I have not yet tried hosting and have no plans atm but I am eager to learn.   Here is what I have deduced so far (some are still speculations as I could not find the exact details of how it works). First, after purchasing a domain from the registrar, you will configure the DNS servers that will be authoritative for your domain in the registrar's DB. I speculate that aside from the names of the dns servers you will also configure the IP addresses of your name servers so a dns lookup on the registrar's DNS servers can give the IP of your authoritative name servers. Also, a whois look up for your domain would return the name servers you have configured.    Now that people have a way to learn your nameservers ip address, they can query your own authoritative name servers for the ip address of your domains and sub domains.  I know it is much complicated than that, but what I want to clarify is how domain registration works and how TLD name servers KNOW who your name servers are so they can redirect requests for your domain to your name servers. At the moment I think that configuring your name servers in your registrar's db also configures the TLD name servers and the whois database. Is this correct? Or is there a separate process? I am confused whether or not the domain registrar also handles the TLD name servers.

I understand that domain name registrars, for each domain they manage, register the authoritative name servers for that domain with its top-level root name server.  My question is: how do they do this? Is there a special protocol they use? How do top-level root name servers authenticate queries from registrars to change authoritative name servers for a given domain? Is that even public knowledge?  For example, say you own example.com. You want to change the authoritative name servers for it. You give your registrar the addresses of the new name servers. So far, so good. They, in turn, echo that change with the top-level root name server (the one responsible for .com). What protocol is used for the query from your registrar? How does that root name server authenticate it? How does it know it's legit?  Migrated from SuperUser (


I'm a beginner in Blender 2.8. I have been following random tutorials on YouTube and even rendered my own project, but they've all been objects, while I started Blender with the aim of modelling characters. And now I feel like I've just been going all over the place and doing whatever looked cool without actually working towards my goal. Where should I start character modelling with Blender 2.8? It'd be really helpful if someone could point me in the right direction and guide me towards useful resources. Thanks!

Since asking for tutorials, videos, resources, links to other content or downloads is considered off topic here, this is a specifically created Community Wiki which gathers resources for Blender and it has been approved by the .  Just write in the appropriate answer/section. If you have concerns, questions, post a  question, so we don't clutter the comments, but you can link your meta question from the comments.  Questions regarding such resources are not allowed anymore, except for very specific and on topic requests (ask on  if you're unsure about your question). Follow the instructions made in the question about how to post, what can be posted, etc.  Learning             Assets    (also see: )   Reference Images/Blueprints (also see: )    Tools    (also see: )      Other   Special Interest ()     Also see the .


Okay - I'm quite new to Stack Overflow (et.all). Is there a way to search for the questions/answers marked community wiki?  I don't always know what I'm looking for - sometimes I'm just lurking to get new insight, and many of the posts, I've stumbled upon so far marked community wiki have been great, so for me it would make great sense to find all community wiki posts for a given Tag.  Make sense?

I tried a search, but I get answers also in the results. I'd like to search only questions.  I tried: wiki:1 question:1 (shot in the dark) but it didn't work, I still get answers in the results.  In contrast, perhaps a way to search only answers would be useful too  So I propose the question and answer search operator to combine


Without using man and in a single command from --help, I'd like to know further information for certain options. I know that for every command, by default the option -h or --help will print a help page with a list of available options. But how can I get only the description of a particular option?   In the web and here in particular we see a lot of instructions and commands and I'd like to read more about it without searching in the full list.  For example, I know that rsync -h means  -h, --human-readable        output numbers in a human-readable format   or that ls -l means  -l                         use a long listing format   How to get that specific information in a short command?

If I want to know the meaning of wget -b, I see the manual by man wget, then search the -b option.     -b    --background        Go to background immediately after startup.  If no output file is specified via the -o, output is redirected to wget-log.   I want to get the result by a command like man wget -b. (Of course this doesn't work.)  Is there a similar way to make it possible?


If not, then how would you prove it? I've thought of multiple examples that do not support this but cannot think of how to go about proving it.

(a) If sup A < sup B, show that there exists an element of $b \in B$ that is an upper bound for $A$.  I have argued that if sup A $\lt$ sup B, then choose an $\epsilon>0$ such that sup A +$\epsilon \in B$. Since $a \le $ sup A for all $a \in A$, it follows $a \lt $ sup A + $\epsilon$ hence sup A + $\epsilon $ is an upper bound of A as well as an element of B.  (b) Give an example to show that this is not always the case if we only assume sup A $\le$ sup B.  I am having trouble extending my argument into an example which makes me think that it may not be correct.   Question: Is my argument for (a) correct? If not how would one show this fact? Can you give an example asked for in (b)? Thanks in advance.  I need to understand how I am assuming what I am supposed to prove in my approach. Can someone elaborate on that please? The other question doesn't really address this issue.


I last visited the US in August 2017 and flew into Fort Lauderdale from the UK. I applied for my ESTA in June which was granted, and travelled to the US on my passport (an e-passport) which expired in October 2017 (roughly, 3 months left on said passport at the time of travel). I was aware there was a requirement for passengers to be in possession of a passport with a minimum of 6-month expiry from certain countries for entry into the US, but when I looked online, the UK was exempt from this:     Are one-year passports issued by the U.K. government valid for travel?      Yes, the passport is valid for travel to the United States.      The fact that it may not be valid for at least six months beyond your date of departure from the United States will not affect your eligibility to travel.      The United States has an agreement with the United Kingdom automatically extending the validity of a passport for six months past the passport’s expiration date. Therefore, your passport need remain valid only for the duration of your stay in the United States.      If you are traveling visa free, and your passport is valid for less than 90 days, you will be admitted only until the date the passport expires.   (Source: )  When I reached the automated security station where I was required to scan my passport, I received a message on the screen stating my passport did not have long enough left on it for the machine to process it. So I was ushered past the machine and into the immigration queue (the same queue which I would have joined if the machine had validated my passport).  I explained my situation to the immigration officer, and he said "We may have a problem here." I was tired and jet-lagged, and didn't fully grasp the situation, nor did I really question it. He went to speak to somebody in the back-room, came back, and permitted me entry into the US, but stated my ESTA is only valid until my passport expiration.  I don't understand what the problem could have been? And how having at least 6-months expiration on my passport would have cleared the problem. The ESTA lasts for two years, so surely the same situation could apply to somebody with 6-months expiration on their passport.

Many countries require a passport to be valid for six months. Sometimes these six months are counted from the date of departure, or from the date of entrance. Even though some of these countries only legally allow you to stay for 30 days or three months. What is the reason such a requirement is in place in many countries?


In Adobe Illustrator CC (latest version) I often find myself copy/pasting artwork from one file to another.  The problem is the artwork in one file is often larger than the destination Artboard, so I have to zoom out, re-size, then move back onto Artboard ... etc.  Is there a way I can 'smart paste' by telling illustrator to paste it, re-size it and fit it somewhere on the target Artboard?  Any help would be greatly appreciated.  Thank You.

I constantly create square background which I should adjust to artboard size.   Almost every time I miss one or two pixels (Retina is good for that), so I looked for one-click feature "click object to artboard size" and didn't find it.  Probably there is a faster way instead of inserting exact parameters of the artboard to the square dimensions?  Illustrator CS6.   Thanks.


I'm looping a buffered reader to pull lines from a dictionary, add them to an ArrayList, and then run them later in the program. Throughout this 15,000,000 line dictionary, blank lines come up about once every 30,000 lines. I don't expect all users of this program to use the dictionary I include, and I don't want to manually pick out and erase each blank line. When the program encounters this line, it throws a pesky NullPointerException, killing the program immediately. I've tried adding a try/catch to add the line if it's not blank and pass over a line that is null using continue. As always, here's my code:                  String line;                 if ((line = br.readLine()) != null) {                     try{                         passwordArray.add(line);                         System.out.println(line);                     } catch(NullPointerException npe){                         System.out.println("The line is null.");                         continue;                     }                 }   Stack Trace:  Exception in thread "main" java.lang.NullPointerException     at net.lingala.zip4j.core.ZipFile.setPassword(ZipFile.java:650)     at zZipCracker.zZipCracker.zZipCracker(zZipCracker.java:96)     at zZipCracker.zZipCracker.main(zZipCracker.java:55)   Line 96:  zipper.setPassword((String) passwordArray.get(0));   Looking at line 96, the blank line is being added and cannot run because the library I'm using requires a password that's length is greater than 0. Line 55 is just a call to the method where this entire process is completed.

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


Prove that if $I-BA$ is invertible then $I-AB$ is invertible.   Though I have found this question already posted and  also it has some answers like   Use:$(I−BA)(I+B(I−AB)^{−1}A)=I(I−BA)(I+B(I−AB)^{−1}A)=I $  I have done it like this.  $I-BA$ is invertible $\implies 0$ is not an eigen value of $I-BA\implies 1$  is not an eigen value of $BA\implies 1$ is not an eigen value of $AB\implies 0$ is not an eigen value of $I-AB\implies I-AB$ is invertible.  I have used the facts the    $AB,BA$ have same non-zero eigen values    Proof:Let $c\neq 0$ be a eigen value of $AB$ corresponding to eigen vector $\alpha$.Then $A(B\alpha)=c\alpha$  Now $(BA)(B\alpha)=B(AB\alpha)=c(B\alpha)\implies c$ is an eigen vector of $BA$ corresponding to $B\alpha$.Also $B\alpha\neq 0$ otherwise $c=0$ .  Similarly every eigen value of $BA$ is an eigen value of $AB$.  How to show that they have same eigen values for if $A,B$ are $n\times n$ matrices?  and    If $c$ is an eigen value of a matrix $M$, then $1-c$ is an eigen value of $I-M$.   Please check whether my answer is correct/not.

The problem is from  Algebra by Artin, Chapter 1, Miscellaneous Problems, Exercise 8. I have been trying for a long time now to solve it but I am unsuccessful.      Let $A,B$ be $m \times n$ and $n \times m$ matrices. Prove that $I_m - AB$ is invertible if and only if $I_n - BA$ is invertible.    Please provide with only a hint.


This is what I think I remember. A ship was sent to colonize a planet with a new generation of humans to save the species from problems on Earth. Once the ship arrived at the destination planet, it stayed in orbit, and robots birthed humans in a controlled environment. Once this generation of children were prepared, they were sent to the planet to populate it. After communication from the people of the new planet stopped, a second mission to investigate was sent from Earth? I think.  I remember that once the second ship arrived and some of the people on the second ship were allowed to go to the new planet there was a realization that there were no police and the population used a form of self-policing. If a person were to commit a crime, the witnesses of the crime were to punish the criminal. Even if that meant killing the criminal.  The society on the new planet did not use any form of currency. Instead the people were allowed to shop for their needs at will with no currency. Simply take what you need as you need it.  A fence painter had the same quality of life as a brain surgeon I think?  I think I read this book around 2009ish. Not sure when it was written or published.

I am looking for the title of a science-fiction book describing a colony (utopia) on another planet that has been established as a social experiment. The inhabitants had been brought up only by robots and therefore work perfectly as a society. I think there is no formal government and people work on what they are interested. If any catastrophe happens, they are able to form groups of specialists who react to the threat. Later there comes a group of outsiders who decide to join and live in the utopia. I am not sure, but author was probably Canadian.


I have many custom service files that I control with systemctl and up until today I have been putting these .service files in /usr/lib/systemd/system/, however today I obtained a new program and it automatically created the .service file in a location I didn't think of - /etc/systemd/system/.  Is this where I should have been putting the service files I have created myself? Both directories appear to work, so ultimately I know it doesn't make a difference, but what does convention dictate? Is there a more correct location to have these custom service files?

Before all the unit files were in /etc/systemd/system/ but now some are showing up in /usr/lib/systemd/system (<- on CentOS, or /lib/systemd/system <- on Debian/Ubuntu), what is the difference between these folders?


Prove that $|(Z/nZ)^*|=\phi(n)$  Can someone please direct me to that proof?  I couldn’t find it on the internet.  Thanks.

Show that number of elements in $(Z/nZ)^*$ is $\phi (n)$. $(Z/nZ)^*$ is set having those classes whose inverse exists.  If we prove that $(Z/nZ)$ has elements whose inverse exists are those who are relatively prime to n. Then my question will be proved  So i write let $gcd(a,n)=1$  $1= as+nt$   $as=1mod(n)$  as ~ 1  so class of a . class of s = 1  i.e inverse of class of a exists  Kindly suggest is this correct or some alternative option  Thanks


select  count(distinct(dateadd(d, 0, datediff(d, 0,checktime)))) as workingdays from departments,  dbo.USERINFO INNER JOIN dbo.CHECKINOUT ON       dbo.USERINFO.USERID = dbo.CHECKINOUT.USERID where  userinfo.name='Gokul Gopalakrishnan' and deptname='GEN/SUP-TBL'  and checktime>='2014-05-01' and checktime<='2014-05-30'   from the above code I am able to find total working days of employee between two dates.  workingdays 20   but  now I want other column name total business days.  I want to calculate total business days between two dates.  workingdays  businessdays 20              21   how can i do this?

How can I calculate the number of work days between two dates in SQL Server?   Monday to Friday and it must be T-SQL.


The below is just me trying to explain my thought process, but it's not necessary to read it to understand my question. My question is just: what does it mean when the rank of a matrix is MORE than the number of variables in the matrix?   Let's say A is an augmented matrix in reduced row echelon form. I know that:   If the rank of A is less than the number of variables in the system of linear equations that A is representing, then there are an infinite amount of solutions to the system (there are x free variables where x = number of variables-rank[A]). The way I justify this is: if there isn't at least one row per variable, at least one variables is "unaccounted for" and therefore can have an infinite amount of values.   If the rank of A is equal to the number of variables (i.e. x = 0 using the above definition of x), then there is a single, unique solution).   But what does it mean when there are MORE non-zero rows than variables? Using the above though process, this would mean that one variable is accounted for more than once. Does that mean there are no solutions to the matrix because one variable is said to have two different values? What if the values agree with each other?  Sorry if this is a stupid question, any help is greatly appreciated!

Consider the system of simultaneous linear equations  \begin{align} a_{11} &x_1 &&\; + \;&& a_{12} x_2   &&\; + \cdots + \;&& a_{1n} x_n &&\; = \;&&& 0 \\ a_{21} &x_1 &&\; + \;&& a_{22} x_2   &&\; + \cdots + \;&& a_{2n} x_n &&\; = \;&&& 0 \\ \vdots\;&\; &&     && \;\;\;\vdots\;\;\; &&                && \;\;\;\vdots\;\;\; &&     &&& \vdots \\ a_{m1} &x_1 &&\; + \;&& a_{m2} x_2   &&\; + \cdots + \;&& a_{mn} x_n &&\; = \;&&& 0 \\ \end{align}  for constants $a_{ij}$ and unknowns $x_j$ , in the case where $m < n$ prove that there  must exist infinitely many solutions to this system of equations.  Okay, so it's pretty easy to prove that this set of equations must have solutions because we have m equations and n values, we x_1=x_n=0 is our trivial solution and if we have more than this one solution, then out null space will be greater than {0} which implies we don't have an injective set of equations. As m is less than n we know the system is not injective, which tells us there must be non-zero solutions. But I want to show these solutions are infinite which means for x_n solutions, the solution should include a parameter. How can I go about this?


I follow some article to convert HTML page to master page and I stocked in snipped section. After converting, my HTML page and other design are rendered in above section of master page and SharePoint header part are rendered in below section. And I don't know how to use these HTML design with my SharePoint nav bar and quick launch and other controls so that it looks like same my HTML page.

There is functionality provided in SP2013 for converting html page to SharePoint master page. I have tried this functionality but each time it convert nothing. Is there any specific method that I need to follow? Or is there any specif layouts of html page need to be converted into SP 2013 master page?


Like in , I also have issues with an increasing CPU use of systemd-udevd, which is only temporarily resolved by (sudo) killing the specific process. However, my issue is not with the wifi, but with NVIDIA graphics:  Reading udevadm monitor gives repeated lines like:  KERNEL[408.860342] remove   /module/nvidia (module) KERNEL[408.901437] add      /module/nvidia (module) KERNEL[408.916478] remove   /module/nvidia (module) UDEV  [408.944573] add      /module/nvidia (module) UDEV  [408.969459] remove   /module/nvidia (module) KERNEL[409.039276] add      /module/nvidia (module) KERNEL[409.060769] remove   /module/nvidia (module)   and checking the less /var/log/syslog gives repeated versions of:  May 13 00:09:28 Lenovo-ideapad-100-15IBY kernel: [28462.698688] nvidia-nvlink: Nvlink Core is being initialized, major device number 240 May 13 00:09:28 Lenovo-ideapad-100-15IBY kernel: [28462.699064] NVRM: No NVIDIA graphics adapter found! May 13 00:09:28 Lenovo-ideapad-100-15IBY kernel: [28462.699186] nvidia-nvlink: Unregistered the Nvlink Core, major device number 240 May 13 00:09:28 Lenovo-ideapad-100-15IBY systemd-udevd[17923]: Process '/sbin/modprobe nvidia-modeset' failed with exit code 1. May 13 00:09:28 Lenovo-ideapad-100-15IBY kernel: [28462.776222] nvidia-nvlink: Nvlink Core is being initialized, major device number 240 May 13 00:09:28 Lenovo-ideapad-100-15IBY kernel: [28462.776574] NVRM: No NVIDIA graphics adapter found! May 13 00:09:28 Lenovo-ideapad-100-15IBY kernel: [28462.776690] nvidia-nvlink: Unregistered the Nvlink Core, major device number 240 May 13 00:09:28 Lenovo-ideapad-100-15IBY systemd-udevd[17923]: Process '/sbin/modprobe nvidia-drm' failed with exit code 1. May 13 00:09:28 Lenovo-ideapad-100-15IBY systemd-udevd[17923]: Process '/sbin/modprobe nvidia-uvm' failed with exit code 1. May 13 00:09:28 Lenovo-ideapad-100-15IBY systemd-udevd[17923]: Process '/usr/bin/nvidia-smi' failed with exit code 12. May 13 00:09:28 Lenovo-ideapad-100-15IBY systemd[1]: nvidia-persistenced.service: Start request repeated too quickly. May 13 00:09:28 Lenovo-ideapad-100-15IBY systemd[1]: nvidia-persistenced.service: Failed with result 'exit-code'. May 13 00:09:28 Lenovo-ideapad-100-15IBY systemd[1]: Failed to start NVIDIA Persistence Daemon.   The drivers are up-to-date, and all other software on the laptop has been upgraded (today) to the latest versions, so I'm not sure what could be causing this issue. I'm not having any problems with the graphics (apart from lag when the CPU usage gets high because of this process), so I'm at a loss.  How can I stop this repeating, and thus swallowing CPU?

Since I upgraded from Ubuntu 16 to 18.04, CPU usage is high. Sometimes 100% cpu usage, and when that happens we can't do anything. If we check on the process systemd-udevd, we find it is using 100% CPU. I have followed an answer to this question:  but now I can't use any browser.  I ran the command sudo mv /lib/udev/rules.d/71-nvidia.rules ~ and now I can't install a new browser or use the old one, and I still have this 100% CPU issue.     Note: I have installed Mint 19 version and found the same issue. I just downgraded to Mint 18.3 and CPU and memory usage are fine. Many others also reported the same issue.


Here is a recent example of this from  on English SE:  The Related questions should be filtered to remove any questions that already appear under Linked. This will avoid confusing the reader by making them think that these are two separate questions. Moreover, it seems that sometimes the score of the question can be different under Linked and Related due to caching, as pointed out in . Update I was not aware of , thanks for finding it. That was filed as a bug report, and was marked as . However, I would like to rebut the argument provided in the staff answer to that question, in order to have this reconsidered as a request to change the design. The staff answer was  It's not truly redundant because, though the links point to the same place, the fact that they're in both lists provides additional information. Specifically, it tells you that the system agrees that the link someone inserted is, in fact, related. The links are already pretty unobtrusive, so the small benefit outweighs the even smaller cost.  From a design perspective, what is the purpose of the sidebar providing links to similar question? The point of this feature, as far as I can tell, is to refer people who searched for this particular question to similar questions, so that they can find more useful information or perhaps the answer they are looking for in another similar question. The list of Related questions is returned by an algorithm which retrieves questions that have lexical and tag similarities. This is not an absolute list. What is ultimately displayed on the page is probably the top X most Related questions, where X seems to be 7. However, this is an arbitrary number. This does not mean that the 8th most Related question found by the algorithm, which is ultimately not displayed, is necessarily not worth displaying to the user. Websites like SO tend to have tons of questions related to a particular topic. It would be a waste to display the same question in both lists, if the purpose of the lists is ultimately the same (to refer users to questions that might help them). A Linked question, might, theoretically, not be all that relevant in reality. The same applies for a question deemed as Related by the algorithm. So, we do not gain any concrete information if a question appears in both lists. On the other hand, having a question appear in both lists is bad UX in my opinion. This is valuable space, and linking to the same post twice not only causes confusion, but can be a hassle. The way it is implemented now, the color change for a hyperlink that you have already clicked is very subtle and might not be discernible by users with low or moderate vision impairment. You would have to open the hyperlink, realize that it’s the same as the one you already saw, and then go back. So, why not link to a question that could potentially help the user, instead of linking to the same question twice?

The Linked and Related sections sometimes contain a link to same same question.  See for example , where one of the Linked questions is same as the first of the Related questions.  I think that this is redundant and duplicate links should be removed from Related section.


i am trying to write a shell script that i can then nohup as it is supposed to run for hours. i am a shell novice so I'm struggling with it a lot.  the script should first open some software (ACE data mining suite), which usually prompts the user for some input (choosing one of many possible input files; this can potentially be avoided by only placing one input file in the directory from which the script is called). i then need to start the algorithm by typing its name in (warmr).  in summary I need the script to:  1) open ACE 2) input file name into ACE (optional, can be avoided)  3) start the algorithm by inputting its name   input in steps 2-3 should be predefined -- i do not want to be prompted for it as i know what i want to run.  so far i have ace_script:  #!/bin/sh  /home/nfg/ACE-ilProlog-1.2.20/linux/bin/ace   adding echo "warmr" or read "warmr" avails to nothing. running ace_script fires up ACE which then complains of an error reading from the stream and shuts down.

I have a script that calls an application that requires user input, e.g. run app that requires user to type in 'Y' or 'N'. How can I get the shell script not to ask the user for the input but rather use the value from a predefined variable in the script?  In my case there will be two questions that require input.


From everything I've been able to find online, JavaScript allegedly uses IEEE 754 doubles for its numbers, but I have found numbers that can work in C doubles, but not in JavaScript. For example,  #include <stdio.h>  int main(){     double x = 131621703842267136.;     printf("%lf\n", x); }   prints 131621703842267136.000000 NOTE: IN AN EARLIER VERSION OF THE QUESTION I COPPIED THE WRONG NUMBER FOR C, but in JavaScript  console.log(131621703842267136)   outputs 131621703842267140. From everything I've read online, both C doubles and JavaScript numbers are 64-bit floating point, so I am very confused why they would output different results. Any ideas?

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


i am trying this sql query in java but its not working i want to insert data in one of the boxes of the row.  This is an image of the row and in the STUDENTS there are 2 names inserted made manually from MysSql, but i want to make it with code. This is my code: String sql = "INSERT INTO CS (Students) WHERE ID='"+ID+"'"VALUES(?,?,?,?,?,?,?,?)";                  PreparedStatement preparedStmt = cn.prepareStatement(sql);                preparedStmt.setString(1,null);                preparedStmt.setString(2,null);                preparedStmt.setString(3,null);                preparedStmt.setString(4,null);                preparedStmt.setString(5,null);                preparedStmt.setString(6,null);                preparedStmt.setString(7,null);                preparedStmt.setString(8,name);                preparedStmt.execute();  but it doest work. And the cn is this: cn=DriverManager.getConnection("jdbc:mysql://localhost:3306/university","root","");

What's wrong with this query: INSERT INTO Users( weight, desiredWeight ) VALUES ( 160, 145 ) WHERE id = 1;  It works without the WHERE clause. I've seemed to have forgot my SQL.


My friend and I live pretty far apart.We really want to play on a LAN world, but it won't let me see it.Can someone help please?

Minecraft's got an "Open to LAN" feature, which can be used to set up a local server when two computers running Minecraft are on the same network. Some young relatives of mine use this to play together whenever they're in the same house, but they'd like to be able to play together from their respective residences.  A server is not optimal because it's a bit complex. I've tried using Tunngle to spoof that the computers are on the same connection to no avail.  How can I convince Minecraft's "Open to LAN" that their two separate computers are on the same network?


I am trying to use the new colorbrewer library and get the following error:     Error: I do not know the key '/pgfplots/colormap/YlOrBr' and I am   going to ignore it.   \documentclass{standalone} \usepackage{pgfplots} \pgfplotsset{compat=1.13} \usepgfplotslibrary{colorbrewer} \usepgfplotslibrary{colormaps}  \begin{document}  \begin{tikzpicture}   \begin{axis}[]     \addplot3[surf, colormap/YlOrBr, samples=41, domain=0:360] {sin(x)*sin(y)};   \end{axis} \end{tikzpicture} \end{document}   Where is my mistake?  Edit: I previously updated pgfplots to 1.13 with the TexLiveUtility under Mac OS 10.11.3. It tells me now that I have the newest version. Also \pgfplotsset{compat=1.13} does not throw an error.

Is there an easy way to 'break' the axis in a pgfplots environment? What I'm talking about is something like     Any minimal plot will do as an example...for example  \documentclass{minimal}   \usepackage{tikz} \usepackage{pgfplots}  \begin{document} \begin{tikzpicture} \begin{axis}[ymin=0, ymax=80] \addplot {x*0};  \addplot {x^2+50}; \end{axis} \end{tikzpicture}  \end{document}   For example, in the below plot,    I want to break the axis from around y = 10 to y = 40.   Any ideas? Does PGF have this functionality? A search for `break' in the manual doesn't yield anything.