Cannot install and upgrade python packages on Ubuntu 14.04

I am trying to install some python packages but I am getting this kind of error every time.  Exception: Traceback (most recent call last):   File "/usr/lib/python2.7/dist-packages/pip/basecommand.py", line 209, in main     status = self.run(options, args)   File "/usr/lib/python2.7/dist-packages/pip/commands/install.py", line 317, in run requirement_set.prepare_files(finder)   File "/usr/lib/python2.7/dist-packages/pip/req/req_set.py", line 360, in prepare_files ignore_dependencies=self.ignore_dependencies))   File "/usr/lib/python2.7/dist-packages/pip/req/req_set.py", line 512, in _prepare_file finder, self.upgrade, require_hashes)   File "/usr/lib/python2.7/dist-packages/pip/req/req_install.py", line 273, in populate_link     self.link = finder.find_requirement(self, upgrade)   File "/usr/lib/python2.7/dist-packages/pip/index.py", line 442, in find_requirement all_candidates = self.find_all_candidates(req.name)   File "/usr/lib/python2.7/dist-packages/pip/index.py", line 400, in find_all_candidates for page in self._get_pages(url_locations, project_name):   File "/usr/lib/python2.7/dist-packages/pip/index.py", line 545, in _get_pages page = self._get_page(location)   File "/usr/lib/python2.7/dist-packages/pip/index.py", line 648, in _get_page return HTMLPage.get_page(link, session=self.session)   File "/usr/lib/python2.7/dist-packages/pip/index.py", line 757, in get_page "Cache-Control": "max-age=600",   File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/sessions.py", line 480, in get return self.request('GET', url, **kwargs)   File "/usr/lib/python2.7/dist-packages/pip/download.py", line 378, in request return super(PipSession, self).request(method, url, *args, **kwargs)   File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/sessions.py", line 468, in request resp = self.send(prep, **send_kwargs)   File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/sessions.py", line 576, in send r = adapter.send(request, **kwargs)   File "/usr/share/python-wheels/CacheControl-0.11.5-py2.py3-none-any.whl/cachecontrol/adapter.py", line 46, in send resp = super(CacheControlAdapter, self).send(request, **kw)   File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/adapters.py", line 376, in send timeout=timeout   File "/usr/share/python-wheels/urllib3-1.13.1-py2.py3-none-any.whl/urllib3/connectionpool.py", line 610, in urlopen _stacktrace=sys.exc_info()[2])   File "/usr/share/python-wheels/urllib3-1.13.1-py2.py3-none-any.whl/urllib3/util/retry.py", line 228, in increment total -= 1 TypeError: unsupported operand type(s) for -=: 'Retry' and 'int'   I looked it up on this site and Stack Overflow and all the solutions suggest installing  wheel   or  setuptools   But I am getting   Requirement already satisfied   The same problem occurs for trying to upgrade python packages. What should I do?


I have multiple tables with data on some clients. What I want to achieve is to output the amount that a certain client was billed for, in the first month he was billed.   So I run the code similar to the one bellow:  SELECT company,clientid,COALESCE (signed.value,reactivated.value) as 'Activation' , Amount FROM `tblclients` LEFT JOIN tblcustomfieldsvalues  as signed  ON tblclients.clientid = signed.relid and signed.fieldid = 5 LEFT JOIN tblcustomfieldsvalues  as reactivated ON tblclients.userid = reactivated.relid and reactivated.fieldid = 27 LEFT JOIN (     SELECT clientid,sum(total) as Amount FROM tblinvoices       WHERE month(invoicedate)=month(Activation) Group by clientid) as f on tblclients.clientid = f.clientid    My problem is that when I do the last join it gives an error : Unknown column 'Activation' in 'where clause'.  If I switch that to current_date the rest of the query works.  Any idea on how to make this work ?  Later edit: I might have oversimplified the query, I also have a COALESCE


Prevent default a link which was added dynamically in jquery 3.6

I wanna preventDefault a dynamically added link that is not getting recognized by the on() method. However, the static link which was already on the page preventDefault()'s itself with the same function. <!DOCTYPE html>       <title>         Testing Phase     </title>         <input type="text" id="txt" name=""> <input type="button" id="btn" name="" value="Add">
     This static link works with the on() method!


I first remember hearing hate for presta valve caps in the video where Lance Armstrong changes a bike tire.  He says:     See that little black thing?  Don't put that back on when you're done... ever.   I thought it was just a joke, until someone commented on a thread of mine (on a bike forum) and said that the valve caps are super lame.    Personally, I always leave my valve caps on because it keeps dirt off of the valve, and in turn out of my pumps.  Now, when I made that argument on the forum the other member commented saying     I totally get the keeping dirt out. Coolness [of taking them off] far outweighs the logic of those little bastards. They have gone the way of wheel reflectors and dork discs.   Any bling will be negated by presta valve caps installed.   Can someone please describe to me why there is so much hatred for these little things?  I get that they kind of resemble a guy's genitalia, but I feel like it's not really that big of a deal.


Recently I had to factory reset my LG Stylo 3 running Android 7. Now the section in my settings that was "Developer Options" is no longer there. How can I get it back?


Best way to monitor ubuntu desktop machine

I'm trying to find a simple solution to monitor all desktop machines of my network (~ 35 Ubuntu desktop). I do not want to use passive monitoring like Munin or Cacti but with an active agent on the desktop, i wish only keep a day or a week of data retention i do not need more.  In fact i plan to use New Relic Server to monitor as my servers. Is there a best way ?


Why is Debian updating old package versions instead of offering new versions? (openssl)

I am a very inexperienced server owner and wanted to make sure I have a fix for heartbleed. After updating, "openssl version" still shows 1.0.1e and I wondered what to do to get a heartbleed free version. After googling I found out about "openssl version -b" and Debians "backporting policy"Since my build is from 8.April I assume I have a fixed version. You can find several discussions of users like me being unsettled by this. They are essentially invalidating the significance of version numbers. Why are they doing this?


What' s $E[Y] = E[f(X)]$? $X\sim N(\mu,\sigma^2)$ and $f()$ is cdf of std normal rv?

What's the expected value of $Y= \Phi(X)$ where $X$ is a normal random variable with mean $\mu$ and variance $\sigma^2$ and $\Phi$ being the cdf of a standard normal distribution?


How can I make a LaTeX poster with all affiliations on the same line, using Beamer?

I'm using the beamer class and all the examples I can find have the author affiliations on different lines. My research project requires us to have them all on 1 line, with superscripts indicating the author's correct affiliation. Here is my current code.   \title{Title goes here}  \author[shortname]{Author1 \inst{1} \and Author2 \inst{2}     \and Author3     \inst{3}} \institute[shortinst]{\inst{1} Affil1 \and                    \inst{2} Afil2 \and \inst{3} Afil3 }   For the record, I tried reading  but didn't understand it. Simple examples are needed with my knowledge level.


Why is a hash of blocks - with index - weaker than hashing the entire thing?

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 :)


CSS breaking on Top Answer User list for long names

I spotted that CSS is breaking on Top Answer User list for long names. The image is not rendered and long names are causing a small scrolling section.


Getting the value of option and display it on the select box

Hi I know this was asked many times, I'm looking for a simple solution.  <select onchange="this.options[this.selectedIndex].value">     <option>--Select--</option>     <option value="1">One</option>     <option value="2">Two</option>   </select>   When a user select an option let's say One the select box would display the numerical 1.  Thanks in advance


$\displaystyle \dfrac{\int_{0}^{1}{(1-x^{50})^{100}}dx}{\int_{0}^{1}{(1-x^{50})^{101}}dx} =$ $  ?$  I tried putting $x=sin(a)$ but I could do nothing about the 100 and 101 powers, they made the integration not solvable for me.  How should I do or approach this question?


If the inner product of Ax with x is 0 for all x, then A=0.

Given matrix $A\in M_{n}(\mathbb{C})$, if $\left<Ax,x\right>=0$ for all $x\in \mathbb{C^n}$, then $A=0_{n}$. (Here $\left<a,b\right> = b^{\ast}a$ where "*" is the conjugate transpose.)  Can anyone help me prove this? By Schur's theorem, A is similar to a strictly upper-triangular matrix, which is nilpotent. I'm not sure if this will help me.   ETA: In the comments I linked to an answer in which the author states "for $\lambda\neq 0$ we get $\left<Ax,y\right>=-\frac{\bar{\lambda}}{\lambda}\left<Ay,x\right>$. For fixed $x,y$ we can vary $\frac{\bar{\lambda}}{\lambda}$, so that $\left<Ax,y\right>=0$. Can someone help me understand that last statement, i.e. how we can get $\frac{\bar{\lambda}}{\lambda}$ to be $0$?


How can I attack with two weapons on the same turn?

So I'm a bit lost on how dual wielding works in D&D 5th edition. In chapter 6 of the PHB, page 195, Two-Weapon Fighting is described as below....     When you take the Attack action and attack with a light melee weapon that you’re holding in one hand, you can use a bonus action to attack with a different light melee weapon that you’re holding in the other hand. You don’t add your ability modifier to the damage of the bonus attack, unless that modifier is negative...   As it describes you need a Bonus Action to attack with the other weapon. So essentially, I would be unable to dual wield weapons and attack with both on the same turn UNLESS I had a spell or ability that granted me a bonus action. Is that correct?  Also there is a Dual Wielding Feat (PHB page 165) that I know has a few bonuses, such as an additional +1 AC and so on. I kind of understand that, Dual Wielding is a passive ability. But I am simply lost as to if I'm capable of two weapon fighting at all.   In the end my goal is to fight people with two shortswords as a Rogue, and have a few daggers on me to throw, in pairs, at a target. This would allow me some ranged attacks, versus always being close the enemy.   Please help me, I'm really confused and lost.


Calculating probability that you are dealt a full house

What is the probability that you are dealt a "full house"? (Three cards of one rank and two cards of another rank.)  why can't I calculate the probability in the following way?  The number of ways I can select 2 suits from one rank = $$13 \choose 2$$ The number of ways I can select 2 suits from one rank = $$4 \choose 2$$ The number of ways I can select 3 suits from another rank = $$4 \choose 3$$  so p should be $$\frac{{13 \choose 2}{4 \choose 2}{4 \choose 3}}{52\choose5}$$  My question is how can I tweak my approach and reach the right answer.


import java.util.Scanner;  public class test {  /**  * @param args  */ public static void main(String[] args)  {     Scanner input = new Scanner (System.in);     boolean US1 = false;     boolean game;     int score = 1;     int wage = 0;        int fin_score = 0;     String ans;      if (US1 == false) {         game = false;         System.out.println (score);         System.out.println("Enter a wager");         wage =  input.nextInt();     }      if (wage < score) {         System.out.println ("What is the capital of Liberia?");         ans = input.next();          if (ans.equalsIgnoreCase("Monrovia")) {             System.out.println ("You got it right!");             System.out.println ("Final score " + fin_score);         }     } } }   I have found a bunch of solutions using InputMismatchException and try{}catch{} but they never work when they are implemented in my code.  is there a way to implement these here? I am trying to make a loop that iterates until the wage entered is an integer


Product notation $\prod$ when product does not commute

This is kind of a dubious question, but is the product notation $\prod$ often used in noncommutative rings?  For example, if $M_i$ are matrices, I guess the common definition of $\prod$ is $$\prod_i M_i=M_1\,M_2\dots$$  but is it also sometimes used as $$\prod_i M_i=\dots M_2\,M_1\text{ ?}$$  If not, is there a common notation for the latter product?


Imagine I'm on a spacecraft that was accelerated to 1.0$c$ could I only move backwards?

Imagine I'm in a sapcecraft1 that is moving with 1.0$c$ or at least is so close to that speed that a few miles per hour would just be left to reach $c$.  So when I'm traveling now in the direction this thing moves, what would hapen? Would I forcefully be unable to move in that direction, so this thing would be like a rattrap while it is moving at that speed?  Or would I be able to catch up with bypassing lightwaves?    1This could be a planet, a man made thing a star or what ever would be most reasonable here.


If a character casts Fog Cloud around themselves before moving away from an enemy, do they provoke an opportunity attack?

Our party was forced to brawl against a group of orcs in order to gain their respect to speak with their chieftain (long story, we had very good reason for doing this). It then became a battle royale.  Our wizard was at low health and next to our paladin, and had the idea to cast fog cloud to capture himself and the paladin within it so he could leave combat. He cast the spell, and then came down to the debate of whether the paladin would get an opportunity attack even though she was blinded.   The wizard was in threat range, but does an effect that causes an area to become heavily obscured cause the Paladin to lose threat range and the wizard be able to successfully flee to another area of the ring?  Or does the paladin still have threat range and attack the wizard, even with fog cloud covering both of them?  I looked over the rules for 15 minutes after this situation, but nothing came up.  It was ruled in-game that it was fine to make an opportunity attack with disadvantage, but that just doesn't feel right. She might have heard the wizard stepping away, but the fog cloud was already in place. By the D&D rules, would the paladin have been able to make the opportunity attack or not?


Are there any non-magical folk born to two magical parents?

I just started re-watching the Harry Potter series, and I had a curious thought.  We know that Harry was born to two parents who were capable of magic, and is able to to do magic. We know that Hermione was born to two Muggle parents, and can also do magic.  Is there anybody born to two magical parents, who is unable to do magic themselves?


How can I switch to Minecraft 1.6.4 so I can be able to load world bioms for Minecraft 1.7.3/.4. I've looked up and tried a lot of thing but cant to seem to the solution. If anyone has an advice it would be very helpful.


Prove: $\int_0^\infty \sin (x^2) \, dx$ converges.

$\sin x^2$ does not converge as $x \to \infty$, yet its integral from $0$ to $\infty$ does.  I'm trying to understand why and would like some help in working towards a formal proof.


Ambiguity of chi-squared test of association; how can the conclusion change using the ''same'' sample?

Recently I have been struggling with the following two questions regarding the chi-squared test of independence / association during reading an article.        Is the chi-squared test able to detect no association between two groups among three at two levels? That is in a 3X2 contingency table.   Does the chi-squared test change its behavior with a larger sample that was otherwise perfectly proportional to a smaller sample?     I prepared a sample data set in R to seek the answers of these two questions. Though my initial discomfort about the chi-squared test have been proven, but over-acceptance of this test statistic in the scientific community have forced me to re-think. May be I have been missing something here.    # Question 1 x1 = c(100, 450, 450) x2 = c(600, 450, 450) d1 = rbind(x1,x2) colnames(d1) = c("Type 1", "Type 2", "Type 3") rownames(d1) = c("No", "Yes") d1 chisq.test(d1) # Significantly associated (not independent), though "Type 2" & "Type 3"  #  were not different at all!   # Question 2 d2 = d1/50 d2 chisq.test(d2) # Not significant!!!  d3 = d2*2 d3 chisq.test(d3) # Significant!!!


When I try to use an image for the world sky material it doesn't show the image in viewport and render, instead it shows the base color and it's black in render view, it is only happening with new .blends , I tried opening other .blends and it works,  as you can see in the picture, the sky is not showing correctly and instead it shows the base color of it which is purple-ish black


“Intel Wireless-AC 9560 : This device is not working”, Even when I am able to connect through Wifi perfectly

I am currently using Ubuntu 20.04. My Laptop uses Intel Wireless-AC 9560 chipset.     I am getting the above comment in the Additional Drivers menu of "Software & Updates". As you can see I am able to connect to my WiFi perfectly without any problems still I see the "This device is not working" message in the Additional Drivers section.  Is this a bug of some kind? How do I solve it such that I am able to see something similar to what I see right now for my Nvidia Graphics.   I can also confirm that I see the required firmware installed in my Laptop (double checked from the Intel website).   Note : I have my exact question . I thought I'll edit it because the image was not in English and didn't state any information except that it wasn't working. But some people (not all :) ) just rejected my review without even giving any proper explanation. Actually, there was the automated reason that I should have written it as a comment or an answer (wow, do people just review edit suggestions for the sake of it?). I hope that at least you'll look at my profile and understand that I don't have commenting powers as of yet (ouch). I request you to not mark this question as duplicate as I need some solution (enter an innocent puppy face).


I have a table with 2 columns plateno and alerts.  table Data  plateno    alerts   A         1   B         2   C         2   A         3   B         2   A         4   A         1   Now I want to get the result like this:  alerts->   1  2  3  4 --------------------------- A          2  0  1  1 B          0  2  0  0 C          0  1  0  0   I mean 'A' has two alerts of type '1',1 alert of type '3' and '4'...and so on..  Here is my query I am trying with  Select count(alert)  from mytable  group by plateno


what is a single word for a quest or journey of self discovery

i need assistance with finding a single word to describe a quest (non religious) for self discovery. i have already tried looking in a thesaurus, to no avail.


Why do we use expectation in reinforcement learning?

In reinforcement learning we use lot of expectations, what's the logic behind them?  Like in reward function, we use expected return instead of return, in value functions V and action-value functions Q we use expectation. Almost every-term in reinforcement learning is written in the form of expectation. Why?  Why do we use expectations?


Why is a multiple defined to require an integer?

Per , a multiple is the product of any quantity and an integer. The requirement for an integer strikes me as subjective. Why do we define a multiple in a manner that require an integer be present in the multiplication step.


What are all the different ways to create an object in Java?

Had a conversation with a coworker the other day about this.  There's the obvious using a constructor, but what are the other ways there?


Who is better for a low computer Ubuntu or others like xubuntu or lubuntu

Ubuntu, Lubuntu, xubuntu, Kubuntu who of this is better for a low PC with only 1 GB ram and who have better programs and games and personalizations.


syntax for using head with filename stored in variable

I'm trying to store the first 5 lines from a file in the variable url.  But I get an error   -n5: command not found   fn_all_urls stores the path to the file /home/urls.txt  My Line is:  url=head -n5 ${fn_all_urls} #get first 5 lines in file echo "$url"   I'm using bash on Ubuntu 18.04 64 bit


Block specfic port for the access of the application from outside with impacting the access to local host scripts

I have setup one application 'phanthomjs' that is running of specific port 6423 I wish that it should be accessible to script that are run locally on the box 'localhost', not accessible from outside.  phantomjs--webdriver=6324  my current script make use of TCP and run on same box and we make use server name as localhost for making connection to the application.  Is there any way to in Redhat Linux box to block the access to this port from outside?


Why is a finite integral domain always field?

This is how I'm approaching it: let $R$ be a finite integral domain and I'm trying to show every element in $R$ has an inverse:   let $R-\{0\}=\{x_1,x_2,\ldots,x_k\}$,  then as $R$ is closed under multiplication $\prod_{n=1}^k\ x_i=x_j$,  therefore by canceling $x_j$ we get $x_1x_2\cdots x_{j-1}x_{j+1}\cdots x_k=1 $,  by commuting any of these elements to the front we find an inverse for first term, e.g. for $x_m$ we have $x_m(x_1\cdots x_{m-1}x_{m+1}\cdots x_{j-1}x_{j+1}\cdots x_k)=1$, where $(x_m)^{-1}=x_1\cdots x_{m-1}x_{m+1}\cdots x_{j-1}x_{j+1}\cdots x_k$.   As far as I can see this is correct, so we have found inverses for all $x_i\in R$ apart from $x_j$ if I am right so far. How would we find $(x_{j})^{-1}$?


Disable Automatic Restarts in Windows 10 Home Anniversary Update

I have a Windows 10 Home PC that is often unattended but doing important work. The work follows no particular schedule, and may take place at any time of day or night.  As things stand, Windows 10 (anniversary update) is configured to automatically restart and install updates during inactive times. The user can configure the inactive times, but the OS forces the user to have no more than 12 active hours a day. This means that the machine may well choose to restart at a time that is highly disruptive to our work and when there is no user around to prevent the restart.  For this reason, I would like to ensure that Windows never automatically restarts. How can I achieve this?


How do I enable Ubuntu (using full disk encryption) to call LUKSsupend before sleeping/suspending to RAM?

This question is related to  by @Stefan, but it is not a duplicate of it. The questions are slightly different: the author simply wanted to know if this had been implemented, while I'm asking for help specifically on how to do this (in a particular way). Additionally, the other question got no useful answers for implementers, except a recent one that merely linked to my attempt at this. Having explained the "duplicate" issue... I'm on Ubuntu 14.04 using full disk encryption (LVM on top of LUKS) and I would like to incorporate luksSuspend into the suspend procedure (and later use luksResume) so that I can suspend to RAM without leaving key material on memory and the root unlocked. I've tried to port a , so far without success: I honestly have no idea of what I'm doing... Can anyone help me port this (or create something like this from scratch)? Or, at least, can anyone point me to documentation about how to hook stuff into the suspend procedures and how to keep the necessary binaries and scripts (such as cryptsetup) available even after all IO to root has been blocked (by luksSuspend)? Concerning how to keep the necessary binaries and scripts available for resume, this  copied them to /boot; I would like however to use something more in the lines what Vianney used in the script I mentioned before, because that approach appears to be a bit more elegant in this aspect. I haven't reached much, but my development can be found on .


$R$ is a sets of positive integers that $((a,b),(c,d))\in R \leftrightarrow a.c=b.d$   Prove that $R$ is an equivalence relation.


According to my textbook the implication P --> Q has the following truth table:    I don't understand the last two rows. For example in the last row, how can we determine P --> Q if all we know is that both P and Q is false. Shouldn't the truth value be unknown in that case?


Extending a homomorphism of a ring to an algebraically closed field

Let $A$ be a subring of a ring $B$. Suppose $B$ is integral over $A$. Let $\Omega$ be an algebraically closed field. Then every homomorphism $\psi\colon A \rightarrow \Omega$ can be extended to a homomorphism  $\phi\colon B \rightarrow \Omega$?


I happened upon  question, where the questioner commented on every answer with "I'd love an up vote!"    Is it correct to flag such clutter, perhaps as not constructive / off-topic, or is there a better way to correct users that beg for up votes (and similar behavior) via comments.


I like knowing / to know things in advance

There is a very small difference in meaning between the two forms. The -ing form emphasises the action or experience. The to-infinitive gives more emphasis to the results of the action or event. We often use the -ing form to suggest enjoyment (or lack of it), and the to-infinitive form to express habits or preferences.    I couldn't understand what they mean by "emphasises the action" and "emphasis to the results". as example, which of the following sentence is correct?        I don't like surprises. I like knowing things in advance.   I don't like surprises. I like to know things in advance.


pgfplots: colorbar: align y ticklables to the right

I have a colorbar in pgfplots and would like to have the y tick labels aligned to the right.  Using  colorbar style={yticklabel style={align=right}}   did not work for me.  The left colorbar shows the default behaviour and the right the wanted bahaviour but with clumsy code (see MWE below).    MWE:  \documentclass{standalone} \usepackage{pgfplots} \pgfplotsset{compat=newest} \begin{document} \begin{tikzpicture} \begin{axis}[ hide axis, scale only axis, height=0pt, width=0pt, colorbar, point meta min=-20, point meta max=20, colorbar style={     height=10cm, }] \addplot [draw=none] coordinates {(0,0)}; \end{axis} \end{tikzpicture} \begin{tikzpicture}%[xshift=2cm] \begin{axis}[ hide axis, scale only axis, height=0pt, width=0pt, colorbar, point meta min=-20, point meta max=20, colorbar style={  yticklabel={$$},     height=10cm, }] \addplot [draw=none] coordinates {(0,0)}; \end{axis}  \foreach \x [evaluate=\x as \xeval using 20-\x*4] in {0,1.25,...,10} \node[anchor=east] at (1.75,-\x) {\pgfmathprintnumber{\xeval}};  \end{tikzpicture} \end{document}![enter image description here][3]


Occasionally, in an otherwise-anonymous paper review, the reviewer will voluntarily sign their name, revealing their identity to the author.  Should reviewers do this, and under which circumstances?  (For the purposes of this question, assume that the reviewer knows the author's name - that is, the review process is not double-blinded.)


Regression on a portion of the graph with columns (at the beginning)

Based on the MWE of , I want to apply the regression only to a portion of the graph as in , but not just the last portion. I want to do regression on the beginning so that the instruction skip first n=3 do not apply.  I can't make it work as I wish, i.e. regression only on the initial part of the graph. The command select coords between index={1}{3} generates an error.  \begin{tikzpicture}  \begin{axis}[ytick={1,...,6}]  \pgfplotstableread{%  X Z Y  1 3 0  2 4 1  3 5 2  4 6 6 }\test  \addplot[only marks, mark=*]       table[x=X, y=Y] {\test};  \addplot[   no markers,dashed, red,       select coords between index={1}{3}           ]            table [      header=false,      x=X,      y={create col/linear regression={y=Y}}] {\test};  \end{axis}      \end{tikzpicture}   When commenting the line with select coords between index the regression applies to all graph, and this is not what I want


How do I calculate standard errors for sums of OLS coefficients?

I'm estimating a simple OLS regression model of the type: $y = \beta X + u$  After estimating the model, I need to generate a weighted combination of coefficients (e.g. $w_1 \beta_1 + w_2 \beta_2$) and estimate standard errors for the combined statistic.  What's the right way to calculate the standard errors of the sum of coefficients?  I've got this far: I have plenty of cases, so it's safe to say that the asymptotic normality assumption is satisfied.  Let's call $s_1$ and $s_2$ the standard errors for $\beta_1$ and $\beta_2$, respectively.  If the $\beta$'s were independent estimates, we could use the basic sum-of-normals function to say that the variance of $\beta_1+\beta_2$ is $w_1^2s_1^2 + w_2^2s_2^2$.  But unless I'm deeply mistaken, the $\beta_1$ and $\beta_2$ aren't independent.  Is there a simple way to fold the variance-covariance matrix of $X$ in to solve this problem?


Circles $c_1$ and $c_2$ with origins $O_1$ and $O_2$ are on plane. $O_1Z$ and $O_1X$are tangents to Circle $c_2$.These tangents intersect $c_1$ in $A$ and $B$.$O_2Y$ and $O_2T$are tangents to Circle $c_1$.These tangents intersect $c_2$ in $C$ and $D$. Prove $AB=CD$   Figure   Things I have done: I was able to Prove that quadrilateral $JO_1LO_2$ is Kite (Triangles $O_2J O_1$ and $O_2L O_1$ are congruent by Angle-Side-Angle). So  $JO_1=LO_1$ and $CO_2=DO_2$. $O_1A=O_1B$ because Both of them are radius.So $JA=BL$.Similar to this,$CJ=DL$. So By Side-Angle-Side, $CJA$ and $DLB$ are congruent.So $AC=BD$. So if I Prove that $AC ||DB$,then $CABD$ will be a Parallelogram So $DC=AB$ will be true.This where I stuck.    I would Appreciate if someone could edit title to something better.


Same priority for masters in a CAN network

I'm aware that messages on the CAN network are assigned priorities. I'm  working on a 2oo3 voting system, and if each of the messages by the three masters are given three unique id's, I'll be making masters among the three masters for the messages i.e. I'll be prioritising among the masters.   I have considered the approach where the slaves keep transmitting the data (either periodically or when they detect a change in the inputs), so that by this way all the three masters can receive the data at the same time and act on the same data. Or, another approach wherein the three masters decide among themselves who will request the slave and when the slave replies, all three masters will process the data at the same time.  I want to know if there is a way, by using a CAN network, I can ensure that the three masters are given the same priority without going with the slave sending approach as mentioned above, and making sure that the masters initiate all actions and not the slaves.   Note: I'm aware of how useful ID's are in arbitration. I just want to know if there a way by which this method is possible.


Thanks for looking into my post. I am new to the stock investment. Current Microsoft book value is 15$ but the Market value is 198$ How to decide value of the stock? How can I say its overvalued and whats the original value of the stock? Which parameter decides its worth to buy or not?


implicit SerialVersionID is used even after defining explicit ID, Why?

Here in my class I have provided the serialVersionUID explicitly, but while using 'serialver' command in command prompt for this same class the UID is generated by the system as well.  Could anyone please throw some light over the understanding of use for explicit  and implicit SerialVersion UID?     class Emp implements Serializable {  private static final long serialversionUID =                              1293488886969693L;          int age;    public Emp(int age)  {      this.age = age;  }   }


Gravity and the Second Law of Thermodynamics

I was wondering about the hypothetical - and apparently improbable -  when I stumbled upon this seeming contradiction.  A certain volume of space with a uniform distribution of particles has maximum entropy.  However, the action of gravity would condense these particles, decreasing the entropy of the system, which would violate the second law of thermodynamics.  My question is simply: what am I missing here?  What is the solution to this contradiction?


Is TLS_RSA_WITH_RC4_128_SHA still a secure cipher to use?

I have read numerous times that the RC4 cipher itself is considered broken in TLS. Still many websites are using the TLS_RSA_WITH_RC4_128_SHA configuration even to date.  Now, I know that sometimes different uses of a cipher mitigate different attack scenarios, so my question is straightforward: Is this particular cipher configuration still considered secure, or are companies just not fast enough in changing to other configurations?


When should a how title end in a question mark?

I've read up on several questions before finally deciding to post. This should be something trivial but I would like to know when it is most appropriate or if it is standard practice to end a how title with a question mark. Here's an illustration.    Scenario one(what I think should be correct):    How to build a smart car.    Scenario two:    How to build a smart car?  In my perhaps misguided interpretation, the second scenario makes it seem like whoever is posing the question would like to let us know  how whatever action they're asking about can be done.  Say I need to ask a question on this forum, can I phrase my title like: "How to ask questions on this forum?" or "How to ask questions on this forum."?  TLDR: How do I use a question mark with a  "How to do x" kind of title?


If X is separable, then ball $X^*$ is weak-star metrizable.

Here is a proof in Conway's book. But there is something I don't understand.   Why choose $\{x_n\}$ in ball $X$? Why not in $X$? I didn't see where the condition $\{x_n\}$ is dense using there. Without $\{x_n\}$ dense I can still get $x^*-y^*=0$.    Thank you!


I've been doing some shell scripting.  It always gives me a headache.  Clearly this language has evolved organically, much as real life languages; new constructs have been dynamically added, constantly introducing new rules and complexities.  Here is an example:     I understand that people like to avoid polluting the variable   namespace; hence the function and the local part, which in turn forces   the use of double quotes, which in turn forces the need to double up   some but not all backslashes (and to know which ones -- oy!). I find   that unnecessarily complicated. Granted, there's a tiny risk of   collision if someone overrides BLUE or whatever, but on the other   hand, the double-quote solution also carries the risk that a terminal   will have backslashes in its escape sequences. And since the contents   of the escape sequences are being parsed in the double-quote solution,   but not in the single-quote solution, such a terminal could mess   things up. Example of the difference:      taken from    It is common to find this level of complexity in technical conversations about shell scripting.  Also there exist a multitude of different shells with subtle syntactic differences.  If a group of experts started from scratch, I bet they could come up with a universal shell scripting language that was much easier to learn, understand and program.  Just as a group of C experts planned C++, or C++ -> C#  There is an ANSI C standard, but is there something similar for shell scripting?  Might it be possible to construct an intermediate shell language, that can expand to various shells?  Is there any effort in this direction, or are we just stuck with things the way they are, like the QWERTY keyboard?


Update Manager crashes, says it needs 3.2.0.58.69 but linux-image-generic on system is 3.2.0.59.70

Recently Update Manager ceased working. Ubuntu Software Centre, when I enter it instead, offers to repair, then fails and offers to repair again, and so on. This is the key sentence I keep getting and am sick of seeing: linux-generic depends on linux-image-generic (= 3.2.0.58.69); however: Version of linux-image-generic on system is 3.2.0.59.70.  It makes no sense to me. Why would linux need an earlier version than the one installed to update itself? I am not certain, but it may be that this problem started after attempting to install Google Chrome. When I checked with Synaptic PM, having tried some of the suggested apt commands at the unmet dependencies thread to no avail, it identified linux-generic as broken, tried to update to 3.2.0.60.71, but then failed again, saying it needed the earlier version (which synaptic says is installed).But that 3.2.0.60.71 is installed instead! So, it says it needs to upgrade, but then acts like it already has. I have not seen anyone else with precisely (no pun intended) this problem on these forums, though someone else unknown has saved virtually the same system response on pastebin .


I want to create a trigger to check what is being deleted against business rules and then cancel the deletion if needed. Any ideas?  The solution used the Instead of Delete trigger. The Rollback tran stopped the delete. I was afraid that I would have a cascade issue when I did the delete but that didn't seem to happen. Maybe a trigger cannot trigger itself.


The Off Topic close dialog has a small alignment issue. The link to  is misaligned with the rest of the text on that line.  The problem only occurs when there is a vote count for that close reason.    Not exactly a major world problem, but I thought I'd point it out.  Firefox 23.0.1, Windows 7


Calculate sum of series $\sum \frac{n^2}{n!}$

I have to calculate sum of series $\sum \frac{n^2}{n!}$. I know that $\sum \frac{1}{n!}=e$ but I dont know how can I use that fact here..


Remove quotes from inbook reference title with biblatex

I use BibTeX and biblatex to create a bibliography. In my BibTeX database I define a @inbook reference with author, title, year and booktitle. Now the problem is that the reference is rendered as:     Author (year): “Title”. In: BookTitle.   I need to remove the quotes around the title.  I already have a custom cite style file with some other definitions, but I did not find where to remove these quotes.


Can any channel be written as $\Phi(X)=\operatorname{Tr}_{\mathcal Z}[U(X\otimes \sigma)U^\dagger]$ for any state $\sigma$?

We know that every CPTP map $\Phi:\mathcal X\to\mathcal Y$ can be represented via an isometry $U:\mathcal X\otimes\mathcal Z\to\mathcal Y\otimes\mathcal Z$, as $$\Phi(X) = \operatorname{Tr}_{\mathcal Z}[U(X\otimes E_{0,0})U^\dagger],\quad\text{where}\quad E_{a,b}\equiv \lvert a\rangle\!\langle b\rvert.\tag1$$ Showing this is quite easy e.g. from the Kraus representation. If $A_a:\mathcal X\to\mathcal Y$ are Kraus operators for $\Phi$, then $$U_{\alpha a,i0} \equiv \langle \alpha,a\rvert U\lvert i,0\rangle = \langle \alpha\rvert A_a\lvert i \rangle \equiv (A_a)_{\alpha,0}.\tag2$$ We can, of course, replace $E_{0,0}$ with any pure state in (1) without affecting the result. This shows that, given any channel $\Phi$ and any pure state $\lvert\psi\rangle\in\mathcal Z$, we can represent $\Phi$ as in (1) (with $E_{0,0}\to\lvert\psi\rangle$). However, what about the more general case of $E_{0,0}\to\sigma$ with $\sigma$ not pure? To analyse this case, consider a channel written as $$\Phi(X)=\operatorname{Tr}_{\mathcal Z}[U(X\otimes \sigma)U^\dagger]\tag3$$ for some state $\sigma=\sum_k p_k E_{k,k}\in\mathrm{Lin}(\mathcal Z)$ (appropriately choosing the computational basis for $\mathcal Z$). The relation with the Kraus operators reads in this case $$\Phi(X)_{\alpha,\beta} = \sum_{\ell k ij} p_\ell U_{\alpha \ell,i k} X_{ij} U^*_{\beta\ell,jk} = \sum_{\ell,k} (A_{\ell,k}XA_{\ell,k}^\dagger)_{\alpha\beta}\tag4$$ with $$(A_{\ell,k})_{\alpha,i} \equiv  \sqrt{p_\ell} U_{\alpha\ell,ik}, \qquad A_{\ell,k} = \sqrt{p_\ell} (I\otimes \langle \ell\rvert)U(I\otimes \lvert k\rangle).\tag5$$ There is now a difference: the number of Kraus operators must be larger than the rank of $\sigma$ (which determines the number elements spanned by the index $k$ in $A_{\ell,k}$). Indeed, a different way to state this same fact is to notice that the $\Phi$ in (3) is a convex combination of several channels: $$\Phi(X) = \sum_k p_k \Phi_k(X), \qquad \Phi_k(X)\equiv \operatorname{Tr}_{\mathcal Z}[U(X\otimes E_{k,k})U^\dagger]. \tag 6$$  This leads me to the question: can any $\Phi$ be written as in (3) for any $\sigma$? More precisely, given $\Phi$ and $\sigma$, can I always find an isometry $U$ such that (3) holds? The question arises from the fact that, because when $\sigma$ is not pure (3) leads to $\Phi$ be a convex combination of other maps as shown in (6), I would think that there should be maps that are "extremal", in the sense that they cannot be written as convex combinations of other maps, and that such maps shouldn't be writable as (3) for $\sigma$ not pure.


I am trying to create a button on a button click and if this created button is also clicked there should be another action.  Here is my code:  //EDIT FUNCTION             $('.edit').on('click', function(e){                 e.preventDefault();                 content = $(this).prop('name');                 id = $(this).prop('id');                 if(!document.getElementById('editnews')) {                     jQuery('#edit').append('
<textarea id="editnews" value="'+id+'"></textarea>
');//is not shown, needed to stop, damn online lib                     jQuery('#edit').append('<button name="'+id+'" class="saveedit btn btn-success btn-mini"> Save</button>');                 }                 $('#editnews').val(content);             });          // EDIT (SEND) FUNCTION         $('.saveedit').on('click', function(e){             console.log("oke");             e.preventDefault();             $.ajax({                 type: 'POST',                 url: 'index.php?page=news',                 data: {editid:$(this).prop('name'), editcontent:$('#editnews').val()}             }).done(function(response) {                 location.reload();             });         });   So the first edit function works fine, but the second not as the button could not be tracked. Hope you can help meh


What's the difference between 'shot' and 'shot at'?

There are two sentences like this.   The hunter shot at the bird. The hunter shot the bird.   Maybe I think that 'shot at' in number 1 sentence means that the hunter shot the bird but missed it. whereas hunter in number 2 sentence succeeded. What's the difference between 'shot' and 'shot at'in meaning? Please, tell me the difference.


Installing Groovy Gorila from Ubuntu 20.04

I have Ubuntu 20.04. I want to install ubuntu 20.10 Groovy Gorilla without uninstalling 20.04 and just want to update it . How can I do that?


C# Can I use an enum as a for loop in place of int

So, I had this bright idea. I need to loop though all directions in a flathead hex. So, given the enum  public enum HexDirectionFlat {     UP, UP_LEFT, DOWN_LEFT, DOWN, DOWN_RIGHT, UP_RIGHT }   Is then this a valid for-loop?  for(HexDirectionFlat dir = HexDirectionFlat.UP; dir <= HexDirectionFlat.UP_RIGHT; dir++)   If so, are there any performence reasons not to use this?


Is it possible to generate electric energy from the radiation of radioactive materials

I wonder if it is possible to generate electric energy from the radiation of radioactive materials like nuclear waste? If it is then wouldn't that also mean that it could be used as an energy source for a very long time since the radiation takes a long time to decay?


Python - how to explain assigning data to array in this case

Please see the code below, why by doing  array[0][0] = 'Tadaaaa'   changed 5 elements instead of one?  First, create an empty array:  x, y = 5, 3  # when you multiply it's copying, so the ids of each item is the same array = [[set()] * y] * x array   I will get:  [[set(), set(), set()],  [set(), set(), set()],  [set(), set(), set()],  [set(), set(), set()],  [set(), set(), set()]]   Then assign a value to elements:  array[3][2].add('BBC') array   I will get:  [[{'BBC'}, {'BBC'}, {'BBC'}],  [{'BBC'}, {'BBC'}, {'BBC'}],  [{'BBC'}, {'BBC'}, {'BBC'}],  [{'BBC'}, {'BBC'}, {'BBC'}],  [{'BBC'}, {'BBC'}, {'BBC'}]]   But when I do:  array[0][0] = 'Tadaaaa' array   I get:  [['Tadaaaa', {'BBC'}, {'BBC'}],  ['Tadaaaa', {'BBC'}, {'BBC'}],  ['Tadaaaa', {'BBC'}, {'BBC'}],  ['Tadaaaa', {'BBC'}, {'BBC'}],  ['Tadaaaa', {'BBC'}, {'BBC'}]]   What's going on here?  I thought I would get something like this:  [['Tadaaaa', {'BBC'}, {'BBC'}],  [{'BBC'}, {'BBC'}, {'BBC'}],  [{'BBC'}, {'BBC'}, {'BBC'}],  [{'BBC'}, {'BBC'}, {'BBC'}],  [{'BBC'}, {'BBC'}, {'BBC'}]]


Need help fixing this Rock Paper Scissors game

The following code does not show any errors, however, when I tried to input user play, I get tons of errors.  public static void rockPaperScissors(Scanner input) {     // TODO Auto-generated method stub     String user = null, computer = null;     int computerRand;     Random num = new Random();     System.out.println("Lets play Rock, Paper, Scissors.\nPlease enter a move\n");     computerRand=num.nextInt(3)+1;      if (computerRand==1)         computer="R";     else if (computerRand==2)         computer="P";     else if (computerRand==3)         computer="S";      System.out.println("Enter user play");     user=input.nextLine();      if (user==computer){         System.out.println("Tie. Try over!");         }     else if (user==("R")){         if (computer==("S"))             System.out.println("Rock beats Scissors. You win!");     else if (computer==("P"))             System.out.println("Paper covers rock. CPU wins..");     }     else if (user==("P")){         if (computer==("S"))             System.out.println("Scissors cut paper. CPU wins..");     else if (computer==("R"))             System.out.println("Paper covers rock. You win!");     }     else if (user==("S")){         if (computer==("P"))             System.out.println("Scissors cuts paper. You win!");     else if (computer==("R"))             System.out.println("Rock beats scissors. CPU wins..");     }              System.out.println("Computer play is: "+computer);  }


Capillary action and conservation of energy

When I dip a paper towel in a cup of water the water gets drawn up due to . How is this reconciled with conservation of energy, as it would seem on the surface that the potential energy of the system has gone up with no work being done?


An individual model in an animation, which isn't effected by compositing and lighting of the animation

I'm trying to create an animation, everything is set up in the animation, including the composition. However since creating it, I wanted to add a logo at the end. I've created the logo and put it into the scene. However when it's on it's own and has it's own personal lighting it looks much better. In the scene the lighting which is needed for the rest of the animation to look good ruins it. Is it possible to fix this?  The compositor nodes, the logo in the scene and the logo before it goes into the scene is as follows:      As you can see the quality of the initial image (even though all settings are the same) is bad when it's placed into the new environment. It no longer looks metallic or shiny.  Ideally i'd like the stars (which are caused by another scene and added in the compositing section) to not shine through the Logo either. So it essentially blocks out the light from behind it.  The light at the moment is coming from two sources, One placed just above and behind the camera at an angle, and one just behind and below the text.  Just for context in case it's needed: The logo spins in from the background to the foreground landing just behind the text which is placed right up against the "lens".  Thank you for any help :)  Edit: Thank you cegaton, the link you posted solved my problem with the stars and already it looks MILES better. Thank you so much for that.  Still struggling to make the D Logo look Darker and more metallic. Going to have a mess around with angles and moving the lights to see what I can come up with. Thank you though cegaton. Big Help!


I am reading GTM 9, and I am trying to compute a structure constants of an abstract Lie algebra using Jacobi identity: $[x[yz] + [y[zx]] + [z[xy]] = 0$. Apply it on $[x_l [x_i x_j] + [x_i [x_j x_l]] + [x_j [x_l x_i]] = 0$ and use $[x_i x_j] = \sum_k a_{ij}^k x_k$.   In the book the equation is    My question is why need not we sum by index m? Just k?


What is the meaning of super script 2 subscript 2 within the context of norms?

I am new to optimization. I keep seeing  that have a superscript 2 and a subscript 2 on the right-hand side of a norm. For instance, here is the least squares equation  min $ ||Ax-b||^2_2$  I think I understand the superscript 2: it means to square the value of the norm. But what is the subscript 2? How should I read these equations?


What is the standard measure of fit quality for least absolute deviation regression (the analog of $R^2$)

When one runs an OLS regression, one often prefers to look at $R^2$ rather than the mean squared error, though both measure goodness of fit. $R^2$ is dimensionless and has some advantageous properties: for example, it's related to other important quantities such as correlation, and it behaves nicely if you scale or translate your data.  When I run an LAD regression, I can look at the sum of absolute errors or the mean absolute error or something. But is there a different statistic, something like $R^2$, that people tend to look at instead?


How do I create a customized ISO of Ubuntu that can be installed on multiple systems, a la OEM configuration?

I am working on created a customized version of Ubuntu (with certain NEEDED customizations) that will, aftewards, need to be installed on others computers. I know about OEM install, but how do I customize the ISO with the packages and setup files I need?


Problems with Chrome browser after suspending the computer on Ubuntu 20.04

Kubuntu 20.04, 64 bit GPU: Geforce GT610 nvidia-driver-390 Chrome Version 85.0.4183.83 Intel i5-4430, core 4, 4 thread , 3GHz RAM: 16GB  Each time I go into suspend mode and then resume, Chrome browser displays the current tab as full of sand of colors, something like dithering in image processing.  Other tabs display glitches too. The current solution is to close and reopen the browser. I tested nvidia-driver-418 but got a black screen problem and reinstalled nvidia-driver-390. The problem is more evident in Chrome, but it sometimes appears in vscode in small areas. There, hovering the mouse over the affected place or resizing the window fixes the problem. In Kubuntu the avatar of the user in the application launcher also shows dithered.  I tested in the same machine with fedora 32 workstation(gnome), nvidia driver, and had the same problems with Chrome browser.  Could it be a GPU problem? Thanks in advance for any directions in how to fix the problem or information on what is causing it.


Outlook Rule - Move mail that is READ and Older than X days

Outlook 2010. Want to create a rule that moves all mail from my inbox to another folder:   Has been read Is older than X days   I was looking at Auto-archiving, but it does not seem to let me be this specific with my criteria.


In the UK (and sometimes Australia), a vacuum cleaner will be called a hoover, regardless of its brand. Likewise, the verb "to vacuum" is replaced with "to hoover".  With a brand name being used in such a way, does it still require a capital letter? Why or why not? Does its capitalisation depend on region?


How, within MS Access can I send a 'test' email to validate that an email can be delivered without it being delivered

As the subject says.  We all know that we can validate the characters in an email address to validate if it is a 'legal' address depending on various standards.  Is it possible to send an email that will be received by the recipients server, but not actually delivered in order to identify if it is a live email address?  I'm currently writing some Access VBA to send out frequent emails to third parties and need to be able to identify before emails go out, that they are going to a live address.


Prevent posts with links to jsfiddle and no code

It's extremely common for people to ask and answer questions with no code other than a link to  or similar service. These of course are not appropriate. I have personally been unable to access jsfiddle for hours due to the site being down while browsing Stack Overflow.   In an effort to help educate people on why this is a bad idea and at the same time improve posts on SO, I suggest some measures be put in place to prevent it from happening.  For example, if the question or answer has:   A link to , , or any other site in a specified list (but let's be realisitic, the one that really matters the most is jsfiddle) No formatted code   ...prevent it from being posted, with a message or link explaining why. There may be edge cases where it does make sense, so perhaps we'd need to allow the user to click through the message and post anyways, but at least they will have been warned/educated.  If we need to discuss whether or not "link only, no code" posts are problematic and not appropriate, then so be it - but I think it's obvious and that topic has been well covered. Is there anything we can do to prevent them and encourage people to put their code in their post?  This issue is very specific to jsfiddle, I would like to see something that directly addresses that. If another site becomes the defacto code demo site, then we can cross that bridge when we get to it or look for more general solutions to this ever growing problem. I think that awareness of the issue is key to preventing it, and people don't read the FAQ nearly enough as it is - we need some direct intervention.  According to the owner/creator of jsfiddle, Stack Overflow makes up . That's a huge amount. Sure they aren't all "link only" posts, but I want to emphasize how much SO is using jsfiddle in particular to dump their code.  People aren't doing this to harm the site, the usually think they are helping out by making their post easier to read. They need to understand why this is actually a problem, and why relevant code must be posted on the site, not somewhere else. If more people understood, I think the problem would start to go away on it's own - but we'd still need something to deal with newer users who aren't familiar with the rules and goals of SO and Stack Exchange, don't hang out in meta, don't read the FAQ, etc. However, the less examples of jsfiddle-link-only posts there are, the less people will imitate them.  I honestly think that if people understood the problem more, it wouldn't be as much of an issue. This doesn't mean blocking jsfiddle, but preventing posts that rely on links to it. A lot of people are confused about that, and ask me "Since when is jsfiddle not allowed?". It's allowed, but your post should hold up without the link. People need to understand that - a warning message would probably be enough.  I do not feel that this specific issue is "status-completed". I think it's still a major problem that's bound to get worse as the months and years go by.  Here are some examples from the past few hours, as of 2012/10/17 6:45 PM EST:                   Here are some more from this morning, 7:30 AM 2012/10/18 (all questions, all within the last couple of hours). I could have easily found a lot more but it was getting boring:                   These were ridiculously easy to find (took me about 3-4 minutes). I don't think the recent change has done very much to help the situatuion. There are literally entire threads on SO that are just passing jsfiddle links back and forth, and it's been like that for a long time - and bound to continue unless something is done to address this specific issue.


Differentiating $ \left( 1 - \frac {1}{x} \right)^x $

I have a calculus question. How does one differentiate $\left(1-\frac{1}{x}\right)^x$, for x>1? It should be positive right?


How do I fix the warning about "conflicting distribution" when doing apt update after installing MKL?

After installing MKL using instructions from , when I do a  sudo apt update   It throws a warning:  Reading package lists... Done W: Conflicting distribution: https://apt.repos.intel.com/intelpython binary/ InRelease (expected binary/ but got )


Is it true that whenever any non rigid body moves, there must be a delay between the ends?

Very sorry if this is still considered a duplicate to , but unfortunately the answer to this question cannot address this because mine is a nonrigid body and involve biological locomotion concepts Basically, there is an annoyingly curious question asked by my friend (quoted here for reference), which I probably have knew that the answer is false but I lacked the key ideas to explain why  如果有一種生物的體積好像銀河系這麼大 連體積都超越很多很多光年 它爬一爬，就已經不知多少光速的千萬倍? (English translation (brackets are his elaborations)): Say if there exists a lifeform the size of a galaxy, isn't it true that when it moves (e.g. crawl by its limbs), the speed of its movement will be many times of the speed of light c (lightyears of distance in a few seconds as measured in its rest frame)?  =================================================================================== Therefore, instead of asking the above question, I am more interested in the answer to the key element that form this question, which is as follows:  Q1. When we wave our arms in air from point A to point B like a fan, it does look like our entire arm is moving in unison from one point to another. Is the true picture that there is a negligible delay between the movement at the base of the arm and the palm from point A to B, thsat only become significant when the movement approaches the speed of light or the arm is lightyears in length? Q2. Is the principle in Q1 applied to all non rigid bodies, thus whenever it was being moved from point A to point B, it looks like as if the whole thing moved in unison, but in reality e.g. the leftmost side reached point B faster than e.g. the rightmost side?  (PS I don't say "topmost" and "bottomost" side is to avoid the gravitational time dilation factor that might be at play, so that the key confusion and the fundamental mechanism at play can be put into focus) ============================================================================= EDIT2: It was pointed that the answer to Q1 was the same as the answer to the rod However of all the answers in the , only the following seemed to touched on the confusion of Q1  BebopButUnsteady When you move one end of the steel rod, it makes part of it bend and stretch which exerts a force on the next section which makes that move and which makes a new part bend and stretch and so on and so on until you reach Alpha Centauri. This moves along at some speed which is characteristic for the metal which is fast enough that we don't really notice in day to day life. All relativity tells us is that that characteristic speed is less than the speed of light - it turns out for real metal its much less than the speed of light.  Elaboration on Q1: why does the hand looks like it is moving like an unbroken whole? do the combined delay due to the nerve impulse and the sequence of muscle contraction is still not slow enough to caused our arm to look disjointed as each cell in the arm move from one place to another in the waving motion? That is, is the principle mentioned by BebopButUnsteady in the link sufficient to address Q1, or is there other subtleties because of the nonrigid and biological nature of the arm?


I have a report that depending on a condition displays other two columns or not. What I need is to resize width of the always visible columns when the condition is set to not display these other two columns in order to not have a huge blank space in the report. Is it possible? All columns displayed:  Huge blank space when the two columns are not to be displayed:  The second image shows the blank space that I need to fullfill by proportionally resize the two columns displayed width.


Regarding spatial relationships, what is the Dimensionally Extended 9 Intersection Model (DE-9IM)?

In plain English what is the ?   What is the meaning of each row/column in the matrix?  How can I use that information to build a relation matrix?


How do I use palettegen and paletteuse on the same command with FFmpeg?

I'm trying to use FFmpeg to convert a bunch of Png's into a gif, while setting the duration of each frame and while using an optimal palette (and other parameters, such as dither) on a single command.  I was reading , but the examples are using two commands and a temporary palette.png file.    Here's what I got, without using palettegen and paletteuse:  -vsync 2 -safe 0 -f concat -i "concat.txt" -y "example.gif"   The concat.txt file contains each frame path and duration, like:  file 'C:\0.png'   duration 0.066    It outputs a gif with a default palette as expected.    So, my question is how can I use palettegen and paletteuse on the same command, without a temporary file?


Can I install Ubuntu 14.04 LTS on a laptop without pae?

Since my computer dates back to 2003, has an Intel Pentium M processor and is therefore not yet equipped with pae, I want to know if it is possible to install newer versions of Ubuntu as the version 12.04 LTS now? Lubuntu and Xubuntu have not worked for me and I do not want to, because their support will end soon.   I have successfully installed version 12.04 (the non-pae version), but should like to the current version Ubuntu 14, is that possible? Would an update to bring something? Because newer Ubuntu versions still run my knowledge, only with pae?


When approaching a sheet of paper between the sun and an object (a Lego here) the shadow of the object seems to get bigger .  Can you please explain why?  Thank you! :)


Is it safe to use a voltage divider for Arduino and DC motor controller?

I have ordered a Dual H-Bridge 12A continuous (30A peak) Polulu motor driver shield for my upcoming (first time ever, a 1.2m long tank made of wood) robot project.   I was thinking about how to supply the power to all the components in the circuit without wasting much power, but the only thing I can come up with is this simple voltage divider connected in parallel to the motor drive:    Knowing the Arduino can handle max 5V I did make sure to make it a bit lower.  But my wonders go to the fact that I am suspicious that connecting the motor driver and Arduino to the same power source isn't a great idea? Or am I paranoid?  And what about power waste by the voltage divider, how can I reduce/minimize it? Make the resistors smaller? (15/10 ohm - but more error and higher current)  Is there a formula to find the most effective R1 and R2?  Do I have to worry about current spikes?  Any other things I could miss in this simple-yet-suspicious circuit?  Also, if I wanted to simulate any possible scenario, which components should I choose in the circuit to keep it as simple as possible (for simulating in Multisim 13)?


Let $n>0$ and $p(z) = z^n + a_{n-1}z^{n-1} + \cdots + a_0$. Then there exists $z$ on $|z|=1$ such that $|p(z) | \geq 1$

I tried a proof by contradiction using Rouche's theorem but I couldn't see how  Rouche's theorem would help in this situation.  What would happen if $|p(z)|<1$ for all  $z$ in $|z|=1$  Could somebody help me out?   New approaches are welcome.


biblatex-biber: How to customize the order in the bibliography?

I am having difficulties with setting up the layout of my bibliography. I would like to have a numeric style which does a none sorting so its order is as it appears in the text. Plus I would like my bibliography entry to look like this (so authoryear style):     References      [1] Surname, Y.G. Year. Title ...   I don't know what to do and can't come up with anymore keywords to look for it. I just started using biblatex.  My setup is as follows:  \documentclass[12pt,a4paper]{scrartcl} \usepackage[english]{babel} \usepackage[utf8]{inputenc} \usepackage{csquotes} \usepackage{textcomp} \usepackage{hyperref}  \usepackage[     backend=biber,     bibstyle=authoryear,     citestyle=numeric-comp     sorting=none, ]{biblatex}  \bibliography{mybib}  \begin{document}  Structures \cite{definition}  \newpage  \printbibliography  \end{document}


Introduction of the vector potential $A_{\mu}$ for the local gauge invariance of the complex scalar field lagrangian

In Ryder, when trying to restore the local $U(1)$ gauge symmetry of the complex scalar field $\phi=\phi_1+i\phi_2$, the final Lagrangian consists of the following four parts: $$L_0=(\partial_{\mu}\phi)(\partial^{\mu}\phi^*)-m^2\phi^*\phi$$ which is the free particle Lagrangian, $$L_1=-eJ^{\mu}A_{\mu}$$ which is where the $A_{\mu}$ is introduced, $$L_2=e^2A_{\mu}A^{\mu}\phi^*\phi$$ and $$L_3=-\frac{1}{4}F^{\mu\nu}F_{\mu\nu}$$ with $F_{\mu\nu}=\partial_{\mu}A_{\nu}-\partial_{\nu}A_{\mu}$, which is gauge invariant. On top of $L_0$, the additional $L_1$ and $L_2$ seems to be quite natural. However, for the $L_3$ part, it doesn't seem to be necessary to me, while Ryder's argument is that "the field $A_{\mu}$ must presumably contribute by itself to the Lagrangian". If we now look back, we know that the $L_3$ term actually gives us the Maxwell's equations. but I'm still not convinced by Ryder's argument. So the question is how do we know that $A_{\mu}$ must contribute to the Lagrangian?


Why pronunciation of "Crooked" is "Crook-ked"?

I've noticed that the pronunciations of "picked" gives its sound like "pick" with final sound "d" but for "Crooked" and "Naked" Why do they pronounce them like "Crook-ked" and "Nake-ked"?   How can I know when i must pronounce the word like "picked" and when I must pronounce the word like "Crooked"?


I have the following enum  public enum Outcome {    DontKnow = 0,    Good = 1,    Bad = 2,    NotBad = 3 }   In my Results class, I have a property with this enum:  public class Result {    public int Id { get; set; }    public string Name { get; set; }    public Outcome FinalOutcome { get; set; } }   As I read data from the database -- using SqlDataReader -- how do I assign its value?  while(reader.Read()) {    Id = Convert.IsDbNull(reader[0]) ? Convert.ToInt32(0) : Convert.ToInt32(reader[0]);    Name = Convert.IsDbNull(reader[1]) ? string.Empty : reader[1].ToString();    FinalOutcome = Convert.IsDbNull(reader[2]) ? WhatGoesHere? : WhatGoesHere?; }


Optimal Blade Pact Warlock with Fiend Patron for DPR/AC without Multiclassing

contains a guide on how to best build an amazing melee Warlock. However, it depends on Multiclassing, which is not allow in the campaign I plan to play in.   The requirements are:    Fiend Patron Blade Pact Optimization goal: Highest DPS/AC.   The original post also had a requirement for Dragonborn as race, but that is not so important for me; if another race leads to a better outcome, so be it.  The campaign I play has the following house rules:    Both ability upgrade and feat instead of a choice Point-Buy of an ability to 16 (with cost 12) is allowed Variant Human is allowed No multi-classing   How to best adapt the above mentioned warlock to our campaign? The basic idea of having a fiend warlock that is strong in melee should be kept, but its fine if other details are changed to improve the build.  It should be playable at lower levels already, not optimized for L20.


How to delete spaces between different shapes after you divide a shape in multiple ones in adobe illustrator?

I'm a beginner with adobe illustrator and for a project we need to split letters(A,B,C..) in many pieces because we need it for an application, and I did that using shape builder tool, pathfinder-divide, knife tool etc but when I save it as SVG(we need it like that) the shapes have a bit space in borders(like a white line). Does anybody know how can I divide without those lines or hide them?


Allow only one website using iptables in a linux router

I have a Linux server I'm using as a router for my internal network. I need to block all the websites except one or two using iptables.  How can I set this up?


Convert a C# DateTime to JavaScript DateTime

I am trying to convert a C# DateTime variable into something that is able to be passed into a Javascript function through NewtonSoft.Json.  At the moment what I am using is:  var jsonSettings = new JsonSerializerSettings(); jsonSettings.DateFormatString = "dd/MM/yyy hh:mm:ss"; string modelFromDate = JsonConvert.SerializeObject(@Model.FromDate, jsonSettings);   However this does not seem to be working since when I use Chrome Dev Tools I get the error that      modelFromDate is not defined   in the following code:  $(".go").on("click", function () {     if (new Date(modelFromDate) < new Date(1994, 1, 1)) {         alert("invalid date");     } });   I am using ASP.NET Core MVC.


Why is /tmp a symlink to /private/tmp on Mac OS X? In other words, why isn't /tmp just a regular directory, like on Linux or BSD? I understand how it works and I don't mind it, I'm just interested in the (historical?) reasoning behind it.


"What have you done since you got up this morning?" or "What have you been doing since you got up this morning?"

Why I have to use here Present Perfect or Present Perfect Continous? Do both mean the same?  What have you done since you got up this morning? What have you been doing since you got up this morning?


Why the $r$ is cubed in the vector notation for of Newton's Law of Universal Gravitation?

I'm learning about astrodynamics on my own and I was wondering why the $r$ is cubed in the vector notation for of Newton's Law of Universal Gravitation:  $$\vec{F}_g=\frac{Gm_1m_2}{|\vec{r}|^3}\vec{r}$$  I am familiar with Newton's Law of Universal Gravitation of the form:  $$F_g=\frac{Gm_1m_2}{r^2}$$  Is there something obvious I'm missing?


How do you prove Gautschi's inequality for the gamma function?

here on math.SE have used as an intermediate step the following inequality that is due to Walter Gautschi:  $$x^{1-s} < \frac{\Gamma(x+1)}{\Gamma(x+s)} < (x+1)^{1-s},\qquad x > 0,\; 0 < s < 1$$  Unfortunately,  that the  is pointing to is not easily accessible. How might this inequality be proven?


What need a template RegEx to get a domain name.  For example, i have:  lifenews.ru www.forbes.com goo.gl ya.ru   and get:  lifenews forbes goo ya


Can a bare infinitive verb as the first word of a sentence form a clause?

I’ve stumbled upon the following sentence reading a blogpost:     Come C++11 (programming language) there are some extra options for our ownership policies.   What does come mean here? It doesn’t look analogous to any clause I’m aware of.  (Well, I understand the general meaning of the sentence but I don’t understand how come in such a syntactic form fits in here. If anything (maybe the blog author was incorrect?), the sentence means that after C++11 has come there are those options.)


What does it mean be gravity propagates with $c$?

I know that gravity propagates with speed of light. Does it mean that if Earth's orbit will disturb after 2 years if a supermassive black hole suddenly appears 2 light years away? Is this related to gravitons which will transmit gravity by travelling at speed of light?


Add 'sequential activity of thread' convenience

At the moment, if I want to look at the activity of a thread I've already read (new Answers, new Comments, new Answer/Question edits), I have to go through a tedious process. Luckily, we got a lastactivity button, but that only shows the latest activity:    By sequential activity, I mean a list of links sorted by latest activity first.  The reason I want this feature is because I often want to know what activity I missed. In my case, this is on threads I've Starred, in which I don't wanna miss a thing. It's easy to miss stuff when relying on lastactivity, especially on busy and/or large threads.    UPDATE: Good to know , but  it would nice if it was easily accessible. An example would be the following, where history links to that activity:  active: 8 months ago (history)


I am a senior Siebel CRM developer having more than 8 years of working experience. Now, I am very keen and excited to learn Salesforce and get certified as soon as possible.   Please guide me where to start from scratch ?


How to keep code running whitin a script

I have a simple script which displays current memory usage, disk usage, and CPU load within a terminal. Here is the code so you can see what I mean:  free -m | awk 'NR==2{printf " | Memory Usage: %s/%sMB (%.2f%%)|\n", $3,$2,$3*100/$2 }'  df -h | awk '$NF=="/"{printf " | Disk Usage: %d/%dGB (%s) |\n", $3,$2,$5}'  top -bn1 | grep load | awk '{printf " | CPU Load: %.2f |\n", $(NF-2)}'   The problem is that it only runs that code within the script 1 time. I need to automatically keep running that script every 1 second without having to keep reloading the script. So basically I just want it in some sort of continuous loop while the script can do other stuff.   The reason I want it to continue to refresh every 1 second, is because it only shows the CPU usage 1 time right when you run the script, but CPU changes frequently, so I need it to keep displaying current data.


Using equation numbers as part of examples

I want to use equations that I have already numbered as part of an example. i.e. above the example I define an equation for potential energy (3.2), then showing students how to use it in an example I want to write out the equation again and use the same number.  Potential energy is given by E=mgh (3.2)  Example: find the potential energy gained of a 30 kg child that climbs 10 m of stairs. E=mgh (3.2)  Can this be done?


How to uninstall ubuntu-desktop in Bash on Windows

I ran the command sudo apt-get install ubuntu-desktop to see if the UI would work within Bash for Windows (which was just released in the Windows 10 Anniversary Update).  Now that I know it doesn't work, I want to uninstall everything it installed (a little over 1,000 packages).  Is there an easy way to do that?  Or is there a way to for me to just start over cleanly with Bash for Windows?


Bind jquery filter to non-existing elements

Is it possible to bind a jquery filter method to elements that don't exist yet? I have a table that is not built before page load, and a table row search that is supposed to filter out rows. Since table rows can also be added and removed, I need to be able to pre-bind the method handler. Example  class ElementSearch {      constructor($input, $elementClass){         let self = this;         this.$input = $input;         this.$elementClass = $elementClass;         this.$input.on('input', function(){             self.filterElements($(this).val());         });          return this;     }      /**      * Hide or show elements according to the search string      * @param {string} search       * @return ElementSearch      */     filterElements(search){         search = search.toLowerCase();         let self = this;         this.$elementClass.filter(function(){              let $this = $(this);             if($this.text().toLowerCase().indexOf(search) > -1){                 $this.fadeIn();             }             else {                 $this.fadeOut();             }         });         return this;     } }   In my App I create ElementSearch before the table is even defined or built. So I try this  this.elementSearch = new ElementSearch($input, $('body table tbody tr'));  Hoping that it will call filter on all tr elements even though they don't yet exist. This doesn't work (this.$elementsClass length = 0) but if I then set it after the table is built, it works.  Is there any way to do this?


Question view counts can be hard to read when over 1,000. For example:   "viewed 10000 times" would be clearer as "viewed 10,000 times":      "viewed 298513 times" would be clearer as "viewed 298,513 times":        Thousands separators are used elsewhere, for reputation:          For question counts:


Number of pairs $(A,B)$ with $\gcd(A,B)=B, A \ne B^2$ with $A,B \le n$

How many pairs $(A,B)$ of integers up to $n$ are there such that $\gcd(A,B)=B$, not counting those pairs where $B^2=A$?   If we consider $n = 5$ we have $25$ possible pairs. They are $$(1,1),(1,2),(1,3),(1,4),(1,5),(2,1),(2,2),(2,3),(2,4),(2,5),\dotsc,(5,5)$$  Of them, $8$ pairs satisfy the above condition. My main objective is to find the number of such pairs if $n$ is given, with a efficient method. One of my friends showed me a method but he didn't state the reasoning behind it.  Here, I'm presenting his method for $n=10$. $$ \begin{align} & 2 \cdot \left(\left(\left\lfloor\frac{10}{1}\right\rfloor - 1\right) + \left(\left\lfloor \frac{10}{2} \right\rfloor - 2\right) + \left(\left\lfloor \frac{10}{3} \right\rfloor - 3\right)\right) \\ =& 2 \cdot ((10 - 1) + (5 - 2) + (3 - 3)) \\ =& 2 \cdot (9 + 3 + 0) \\ =& 24 \end{align} $$ Can anyone explain the reasoning behind the above method in details and clearly?


Is there a problem with Beamer in the latest MiKTeX update?

This is about MiKTeX Revision 2.9.6360.  Immediately after the latest MiKTeX update, my Beamer files stopped compiling.  When i tried to compile a file that had been working fine I got a Package installation popup saying:  tex\latex\beamer\beamerbasemodes.sty  Is missing.  It is part of the following package  beamer   So i clicked to have it installed.  All that achieved is that i got an error message  ! LaTeX error: File 'beamerbasemodes.sty' not found   I repeated this a few times with minor changes to the file, and then went to the MiKTeX Package Manager to see what parts of Beamer are installed.  It said none were.  Either the update had removed Beamer, or the attempt to install beamerbasemodes on the fly had done it.  So I reinstalled it by hand.  In fact i did this several times in various ways.  It made one difference.  Sometimes the problem package was identified as  translator.sty  In case it would help, I ran Update FNDB and restarted my machine.  Each time I installed Beamer, the Package Manager then reported that Beamer was installed.    But when I tried to compile the file, the same things happened all over.   And when i went back to the MiKTeX Package Manager it reported Beamer is not installed.   Is Beamer now out of date?  Or is this a problem on the new update?  Is there a simple fix i can use?


On a BIOS-GPT system (i.e. no UEFI):   I partition my disk this way:   1) 2MiB with the bios_grub flag  2) 1GiB ext2 for /boot  3) 30Gib ext4 for / for Gentoo.  4) the rest divided for other distros and for /home.   My question is concerning the second partition, the ext2 for /boot/.  In gparted, do I need to set the 'boot' flag?  I read conflicting  about it:         "Some buggy BIOSes or EFIs configured to boot in BIOS/CSM/legacy mode might also have problems with booting from GPT labeled disks. If that is the case, it might be possible to work around the problem by adding the boot/active flag on the protective MBR partition which has to be done through fdisk with the -t dos option to force it to read the partition table using the MBR format."    ...    "When using the UEFI interface to boot the system (instead of BIOS), mark the boot partition as the EFI System Partition. Parted does this automatically when the boot option is set on the partition:"    ...    "Type a to toggle the bootable flag on a partition and select 2. After pressing p again, notice that an * is placed in the "Boot" column."       elsewhere I read that the 'boot' flag on an uefi system was for a partition of type fat32 (vsfat).   Basically, I am confused: the 'boot' flag is to be used for BIOS or for EUFI or both?  Should I set it for my ext2 /boot/, or I shouldn't, or it doesn't matter either way?


Normalize Y-axis by y=(y-min(Y))/(max(Y)-min(Y))

I am new to pgfplots and would like to get your help on my question. Basically I need to read y value from a file that only contains a list of data (in one column), normalize each value by y=(y-min(Y))/(max(Y)-min(Y)) where max(Y) is the maximum value in the list and min(Y) is the minimum value in the list and plot them. For example, if I have {1,2,3,4} then on the plot, the value of y will be {0, 1/3, 2/3,1}.   I use \addplot table [x expr=\coordindex, y index = 0] {filename}; to draw x and y on the plot. What's the normalization expression for y? Is there existing function to do that? If not, can we extract the max(Y) and min(Y) in pgfplots?


Is there a term for the acceptance of a made up term that then became the name of the object/idea/action once it was invented?   Example: Cyberspace. It was first used by William Gibson in his cyberpunk novels, but when actually invented, it now is widely used across the world (or at least across the United States).  Is there a term for this phenomenon?


getting an runtime Exception in thread "main" java.lang.NullPointerException please help to resolve the same

I am new in the programming field, so while trying to run the below code I am getting the java.lang.NullPointerException at line number 19 and 32.   import java.io.*; import java.util.*; import java.text.*; import java.math.*; import java.util.regex.*;  public class Solution {      static int binary[];     static int i = 0;      static void DecToBin(int num)     {         while (num > 0) {              **binary[i++] = num % 2;**             num = num / 2;          }              for (i = i - 1; i >= 0; i--) {                 System.out.println(binary[i]);             }     }      public static void main(String[] args) {         Scanner sc=new Scanner(System.in);         System.out.println("Enter a decimal number");         int n=sc.nextInt();         **DecToBin(n);**      } }   Output:   Enter a decimal number 4 Exception in thread "main" java.lang.NullPointerException at Solution.DecToBin(Solution.java:19) at Solution.main(Solution.java:32)


How does oracle sql's to_date and iw work internally

The following sql is to calculate the week number of 20811231, the result is 1, which means 20181231's year week is 201901  select to_number(to_char(to_date('20181231','YYYYMMDD'), 'iw')) from dual   What I am doing now is to write a java method that does the same thing as the above sql: input 20181231, the method will output 1,and for other inputs, the output should also be the same.  I want to ask how I can achieve this using java.util.Calendar class


How do I detect players being on a block without pressure plates or tripwires? Preferably with command blocks. This is on Minecraft: Java Edition.


Why is the Cantor function not absolutely continuous?

Is there an easy way to see that the Cantor function is not absolutely continuous that directly uses the definition of absolutely continuous?


Did Spike get his reflection back with his soul?

I watched the episode  of Buffy the Vampire Slayer.  How come it takes Principle Robin Wood seeing Spike fighting to know he was a vampire?   Only a scene earlier Robin Wood is driving a car with Spike on the back seat, he seems to directly look in the mirror but surely if Spike has no reflection he’d have worked out right away he’s not human.


I understand why $e^{i\pi} = -1$and as a result  $e^{i2\pi}=\left(e^{i\pi}\right)^2=1.$ These results can be confirmed using Euler's formula  But why does $e^{i\pi/3}\neq -1$ as we can write it $(e^{i\pi})^{1/3}$ and as such $(-1)^{1/3}$ the cubic root of $-1$ is $-1$ itself.  Yet using Euler's formula we get $e^{i\pi/3}=\frac{1}{2}+i\frac{\sqrt 3}{2}$.


Everytime I do the CanPlaceOn command it says i'm wrong

My command is  /give @p lever 1 0 {"can_place_on" : {"blocks" : ["diamond"]}}   and it keeps responding by saying     Component 'can_place_on' is not a supported component.   What did I do wrong?


I have heard mixed responses on this topic, so what is a sure fire way to destroy a PHP session?    session_start(); if(isset($_SESSION['foo'])) {    unset($_SESSION['foo'];    ... } session_destroy();   In the most simple of cases, would this sufficient to truly terminate the session between the user and the server?


Let's say we have $2$ particles facing each other and each traveling (almost) at speed of light.    Let's say I'm sitting on #$1$ particle so in my point of view #$2$ particle's speed is (almost) $c+c=2c$, double light speed? Please say why I am incorrect :)    EDIT: About sitting me is just example, so in point of view of #1 particle, the second one moves at (almost) $c+c=2c$ speed?


If "clearly evident" is redundant, what word or phrase suggests being indisputable but not readily apparent?

A  asks whether the modifier "clearly" changes the meaning of "evident". I would have said, prior to examining a few dictionaries, that evident did not necessarily mean readily apparent, but to my surprise it does.  This brings me to ask what word or expression would mean something can be taken as a true fact, but not through an easily constructed (not obvious or readily apparent) rationale?   For example, if Sherlock Holmes says something is true while everyone else is still sitting on their hands, then it is evident to Holmes, but not to the rest of the world. So, from everyone else's point of view, it is not readily apparent, and (by definition) apparently it is not evident, clear, or clearly evident at all, based on the dictionary definitions. But (let's stipulate) it is true and deducible from the observable evidence. What would we call this?  Update  An update is highlighted above. I can see from some of the answers and comments that I may have gone off my mark with the phrase "not through an easy-to-follow rationale”, and I have modified the question to correct this. I understand that there can be rationales, arguments, or proofs that, once explained, may or may not be easy to follow. What I intend is that the rationale to support the indisputable conclusion is not (initially) easy to recognize or construct (not readily apparent) in the first place. I apologize for the confusion. (The original can be seen in the change history.)  Update 2  Shortly after offering a bounty to this request, I recalled a single word that I now believe is a very good match to the parameters specified in this inquiry as it is stated above. That word has not yet been suggested (or approached) by any answer or comment (active or deleted) at the time of this edit. This request is changed to a single word request. (However, if you feel a single word fits well but not without some additional supporting words, please offer your thoughts in an answer.) While my curiosity for the term has already been met, the request and bounty remain as an open challenge. I will post my own answer once the bounty has expired and been awarded.


What are "preferred" stocks? How are they different from normal (common) stocks?

What are "preferred" stocks?  How are they different from normal (common) stocks that you can buy on a stock exchange?


Why is there a diode connected in parallel to a relay coil?

In most electrical circuits with a relay, a diode is connected in parallel to the coil of the relay. Why? Is it always a good practice?


How can I mount partition disk0s4 that became inaccessible after a clean installation of Mountain Lion?

The hard drive on my MacBook Pro has two partitions. One with the OS and the other with data.  Yesterday, from a USB boot drive, I performed a clean installation of Mountain Lion to the OS drive. I created the USB boot installer from InstallESD.dmg that I received from purchasing the OS from the Mac App Store.  Now I can't see or mount my data partition.  I'm wondering if there's a problem with the MBR. In Disk Utility it shows up as "disk0s4", but it's greyed out.  Any ideas on how I can mount the data partition so I can get my data off it?  For diskutil list disk0 the result is:   /dev/disk0    #:                                 TYPE NAME         SIZE       IDENTIFIER    0:                GUID_partition_scheme             *500.1 GB   disk0    1:                                  EFI              209.7 MB   disk0s1    2:                            Apple_HFS MacBook OS    99.5 GB   disk0s2    3:                           Apple_Boot Recovery HD  650.0 MB   disk0s3    4: 46860E2C-2310-4F96-99F6-616D0B4CB55D              399.6 GB   disk0s4   Here's the result of diskutil info /dev/disk0s4  Device Identifier:        disk0s4 Device Node:              /dev/disk0s4 Part of Whole:            disk0 Device / Media Name:      MacBook Data  Volume Name:              Not applicable (no file system)  Mounted:                  Not applicable (no file system)  File System:              None  Partition Type:           46860E2C-2310-4F96-99F6-616D0B4CB55D OS Can Be Installed:      No Media Type:               Generic Protocol:                 SATA SMART Status:             Verified  Total Size:               399.6 GB (399629668352 Bytes) (exactly 780526696 512-Byte-Blocks) Volume Free Space:        Not applicable (no file system) Device Block Size:        512 Bytes  Read-Only Media:          No Read-Only Volume:         Not applicable (no file system) Ejectable:                No  Whole:                    No Internal:                 Yes Solid State:              No


How to find the right questions that I can answer?

I believe most people . Surely some use the "" link above, or the others filtering options. Others just attack them randomly when they're feeling a thrust of need to answer questions. And there are the foreigns who come across questions for whatever reason (such as google) to eventually give an answer.  I don't have a method, but I see there are way too many unanswered questions (right now,  and ). There's probably at least one question there that I could answer, but I'm finding it quite too hard to find the ones that are "right for me".  So, how do you do to find your answerable questions?  I couldn't even find a duplicate to this, as I figure there must be one.


Where are the developer options in Android 4.2?

I wanted to access the developer options to enable adb access on Android 4.2 but cannot find it.  How can I enable that?  Once I've activated the menu, how can I hide it again?


i create a custom page to display loop of cpt with custom field.   I need to add a numberic pagination and i try with this code but not work.  Functions.php  function pagination_bar() {     global $wp_query;      $total_pages = $wp_query->max_num_pages;      if ($total_pages > 1){         $current_page = max(1, get_query_var('paged'));          echo paginate_links(array(             'base' => get_pagenum_link(1) . '%_%',             'format' => '/page/%#%',             'current' => $current_page,             'total' => $total_pages,         ));     } }   custompage.php   <?php $paged = ( get_query_var( 'paged' ) ) ? get_query_var( 'paged' ) : 1; $loop = new WP_Query( array( 'post_type' => 'salmi',         'posts_per_page' => 15,         'paged'          => $paged ) ); while ( $loop->have_posts() ) : $loop->the_post(); ?>

<?php the_title(); ?>

             <?php if( get_field('audio_salmi') ): ?>                 <a href="<?php the_field('audio_salmi'); ?>" >             <?php endif; ?>             <?php if( get_field('salmi_pdf') ): ?>                 <a href="<?php the_field('salmi_pdf'); ?>" >             <?php endif; ?>

              <?php pagination_bar(); ?>       <?php endwhile; wp_reset_query(); ?>    Where is wrong?? Thanks


Here is the code:  import bpy import csv import sys csv_path = sys.argv[1]  file = open(csv_path) reader = csv.reader(file)  header = next(reader) # 1st line is header  data = [ ] for row in reader:     name0 = row[0]     name1 = row[0]     pathout = 'test-videos/' + row[5] + '.m4v'     s = bpy.context.scene     f = s.objects['FirstName']     f.data.body = name0     f1 = s.objects['FirstName01']     f1.data.body = name1+'?'     bpy.context.scene.render.filepath = pathout     bpy.ops.render.render(animation=True)  bpy.ops.wm.quit_blender()   And here is the error message:  Read blend: /PI-SAT/proj001/proj001-master.blend Traceback (most recent call last): File "/PI-SAT/proj001/proj001master.py", line 9, in <module> header = next(reader) # 1st line is header File"/Applications/Blender/blender.app/Contents/Resources/2.79/python/ lib/python3.5/codecs.py", line 321, in decode (result, consumed) = self._buffer_decode(data, self.errors, final) UnicodeDecodeError: 'utf-8' codec can't decode byte 0xef in position 23: invalid continuation byte Error: File format is not supported in file '/PI-SAT/proj001/test.csv' ... opened default scene instead; saving will write to /PISAT/proj001/test.csv   I have read the file with a different script using the exact same code as in lines 2 - 15 and then printing the names and pathout. Running the script from the command line, not from within Blender, it works perfectly.  I have also run the part of the script within the for loop outside of the loop as a script from the command line and it works perfectly.  What am I missing about the CSV file? I created it in Excel on my Mac; is that a problem?


class A{   int i;   public:   A():i(0){cout<<" A : "<<i<<endl;}   A(int a);     virtual int val(){ return i+1; }  };  class B :public A{  int i;   public:   B():A(),i(0){cout<<" B : "<<i<<endl;}   B(int a):A(a),i(a) {   }    int val(){  return i;} };   A::A(int a):i(a){    cout<<" A ; "<<i<<endl;    A* ap = new B;    cout<<" from A "<<ap->val()<<endl; ///expect 1 but got 0; }  int main(){   A a(5); }   I expected the return val of call ap->val() to be 1, since I thought virtual mechanism doesn't work in constructor, but here I got value to be 0, since ap->val() resulted in call to B::val(). Why ?


when i execute this schedule apex class from developer console  the class is scheduled at 4 different timings as queue. when "schedule Job2" running i got this exception in debug log shows      "|EXCEPTION_THROWN|[21]|System.AsyncException: The Apex job named   "Scheduled Job0" is already scheduled for execution"   and in debug log the future call shows  : "Number of future calls: 1 out of 50"  but  i'm not getting the any records pulling from external source   this is scheduled class  global class SchedulingService implements Schedulable {      global void execute(SchedulableContext SC){            ServiceNowUpsert.GetIncident('abcd','1234','https://abcd.service-now.com');                    String day = string.valueOf(system.now().day());           String month = string.valueOf(system.now().month());           String hour = string.valueOf(system.now().hour());           String minute = string.valueOf(system.now().minute() + 15);           String second = string.valueOf(system.now().second());           String year = string.valueOf(system.now().year());            String cronStr = '0 0,15 * * * *';//changes required           String strJobName = 'Job-' + second + '_' + minute + '_' + hour + '_' + day + '_' + month + '_' + year;           // String strSchedule = '0 ' + minute + ' ' + hour + ' ' + day + ' ' + month + ' ?' + ' ' + year;           //System.schedule(strJobName, cronStr, new SchedulingServiceNow()); //changes required           System.schedule('Scheduled Job0', '0 0 * * * ?',  new SchedulingService ());              System.schedule('Scheduled Job1', '0 15 * * * ?', new SchedulingService ());           System.schedule('Scheduled Job2', '0 30 * * * ?', new SchedulingService ());           System.schedule('Scheduled Job3', '0 45 * * * ?', new SchedulingService ());            for( CronTrigger c:[Select State,Id,EndTime,CronExpression From CronTrigger where                                               NextFireTime= null  AND State='DELETED' Limit 100]){                          System.abortJob(c.id);                 }             }        }     This is my apex class   global with sharing class ServiceNowUpsert {      @TestVisible static HttpResponse res;      @future(callout=true)      global static void GetIncident(String username1, String password1, String endpointUrl1){           Http http = new Http();         HttpRequest req =  new HttpRequest();         Blob headerValue = Blob.valueOf(username1 + ':' + password1);         String authorizationHeader = 'BASIC ' +         EncodingUtil.base64Encode(headerValue);         req.setHeader('Authorization', authorizationHeader);         req.setHeader('Content-Type', 'application/json');  //displays data in JSON format           req.setEndpoint(endpointUrl1+'/api/now/table/incident?sysparm_query=sys_updated_onONLast+hour%40javascript%3Ags.hoursAgoStart%282%29%40javascript%3Ags.hoursAgoEnd%280%29&sysparm_fields=impact%2Cincident_state%2Cshort_description%2Csys_id%2Ccontact_type&u_sftype=true');                req.setMethod('GET');           res = http.send(req);         System.debug('MyResult == :'+res.getBody());            Deserialization.ResponseResult theresult1 = (Deserialization.ResponseResult)JSON.deserialize(res.getBody(),  Deserialization.ResponseResult.class);         System.debug('MyResult == :' + theresult1 );           List<Case> casesToUpsert = new List<Case>();                 for(Deserialization d : theresult1.result ){                  Case c = new Case();                  c.Priority = d.impact;                 c.Status = d.incident_state;                 c.Subject = d.short_description;                 c.ServiceNowId__c = d.sys_id;                 c.Origin = d.contact_type;                  casesToUpsert.add(c);          }         system.debug('Cases to UPsert ::: ' +casesToUpsert);          if(casesToUpsert.size()>0){             Database.upsert(casesToUpsert,false) ;         }              }  }   How to work my scheduled class perfectly running for every 15 mins and pulling the records from external source?