Prove that $a+b+c\le \frac {a^3}{bc} + \frac {b^3}{ac} + \frac {c^3}{ab}$

One of my friend had just given me an inequality to solve which is stated below.   Consider the three positive reals $a, b, c$ then prove that      $$a+b+c\le \frac {a^3}{bc} + \frac {b^3}{ac} + \frac {c^3}{ab}$$   I have solved this inequality very easily using Muirhead. But my friend has no idea what Muirhead inequality is. So I want to know whether there is any other method to solve this problem except for Muirhead's inequality.


If A and B are correlated with C, why are A and B not necessarily correlated?

I know empirically that is the case.  I have just developed models that run into this conundrum.  I also suspect it is not necessarily a yes/no answer. I mean by that if both A and B are correlated with C, this may have some implication regarding the correlation between A and B.  But, this implication may be weak.  It may be just a sign direction and nothing else.    Here is what I mean...  Let's say A and B both have a 0.5 correlation with C.  Given that, the correlation between A and B could well be 1.0.  I think it also could be 0.5 or even lower.  But, I think it is unlikely that it would be negative.  Do you agree with that?    Also, is there an implication if you are considering the standard Pearson Correlation Coefficient or instead the Spearman (rank) Correlation Coefficient?  My recent empirical observations were associated with the Spearman Correlation Coefficient.


How to find the value of the infnite product  $\frac {7}{9}$x$\frac {26} {28}$x $\frac {63} {65}$x . . . x$\frac {n^3-1} {n^3+1}$x . .  Somebody please help me.


Suppose that p ≡ 3 (mod 4)   and $r = \frac {p-1}2$  Show that $r! \equiv (−1)^k \pmod p$  where k is the number of non-quadratic residues modulo p which are smaller than $\frac p2$  I know from Wilson's Theorem for a prime p:  $(p−1)! \equiv −1 \pmod p$  I don't know where to start from ..   I managed to show that   $r! \equiv \pm 1 \pmod p$  any help or hint will be appreciated


I am trying to mirror or rotate(180) my layer some thing like  this "-->" to this "<--". Is there any built in plugin or support available to do this job or i have to write code in pyqgis?  I don't know what the exctly term is better to asked either it is invert, filp, rotate or mirror.


Change the default editor when sudo visudo

When doing sudo visudo, the default editor is nano. I want to change it to vi or vim.     I already made vim the default editor, and use it as a substitute for gedit to open php, .txt, .c and .h files, by placing a vim.desktop file in ~/.local/share/applications/ and by correctly editing either  ~/.local/share/applications/mimeapps.list or /etc/gnome/defaults.list. However apparently this does not apply to nano.    Any clue ?


How to find program name(s) of an installed package?

When I have installed a package using apt, is there a way to find out by which command(s) I can run the installed program(s)?  For instance, the package httpcode is not available as httpcode, and the package description (apt show httpcode) does not explain how to run it. How could I have found out that it’s run via hc from the command line?  There are two slightly hacky workarounds I found:    Assuming that programs are by default installed in usr/bin, I ran ls -ltc | head -n 10 to find recenlty touched files there, and indeed I found hc. Similarly to 1, dpkg -L httpcode returns a list of files created by installing the package, which also lists /usr/bin/hc.   Is there a better solution to this problem that doesn’t hinge upon the intuition of where the program might be stored on disk?  I also found that man httpcode does open the man page of the program, even though I called it with the package name as argument. Does this always work (if the program provides a manpage)?


Prove $\operatorname{rank}(AB) = \operatorname{rank}(B)$

I am given the info that A is an invertible  m by m matrix and B is a m by n matrix. By solving for the null space $ABx=0$, I get $A^{-1}ABx=A^{-1}0$, therefore $Bx=0$. I concluded that the null spaces of A and AB must be equivalent, and therefore the nullity(AB) = nullity(B) = some number p. Therefore rank(AB) = n-p = rank(B)   (because both AB and B are m by n matrices).   Is this proof valid, specifically the null space step?


Is there a standard pronunciation for gender-neutral -@ or -x

More and more I see, especially in activist communities, Spanish-derived words ending in x or @ in order to neuter the gendering inherent in the original language. For example: latinx (or latin@) as opposed to latina and latino. How, though, are these endings pronounced? Please provide evidence of how this orthography is most commonly pronounced. Note 1: I recognize this is in an English Language site, rather than a Spanish language site, but this phenomenon is very much happening in English, albeit with Spanish loan words. Therefore the question is relevant to non-Spanish-speaking English speakers. Note 2: A question like this can lead to politically charged or, at least, sarcastic comments. Please refrain from bringing in your biases for or against. Note 3: This question is not seeking opinions as to how some people pronounce the suffixes. Answers should address evidence of a developing orthodoxy in pronunciation.


Open new Chrome window with different profile from command line

I want to run a command line that opens a new chrome window with another profile. I tested the following commands: Preconditions:  I have two profiles: Profile 1 and Profile 2  Chrome is already running with Profile 1   open -a "Google Chrome.app" --args --profile-directory="Profile 2" The above command does nothing other than bringing focus to the currently running chrome with Profile 1 I also tried: open -a "Google Chrome.app" --args --profile-directory="Profile 2" --new-window The effect is the same. I want to run a command line that opens a new chrome window with Profile 2 while there is already a Chrome window running with Profile 1


I have to render an image of 27000 x 7000 for a 150dpi print. The scene is quite big, but cycles preview and a render in 2700x7000 works as expected.  If I hit render my memory raises up to 20gb, but my cpu usage is at 5%. Why cycles does not using the full cpu power during the render process?  Here are my rendersettings:  Pathtracing Samples:3000 Tilesize: 64x64 Bounces: Max 12 | Min 3 Diffuse: 4 Glossy: 4 Transmission: 12 Volume: 1   Is there a way to optimize things?


There exist two functions f, g satistfying: $\int f(x)·g(x)dx = \int f(x)dx ·\int g(x) dx$?

I know that the integral of two functions is not the product of the integrals, but there exist two functions f, g satistfying:  $$\int f(x)·g(x)dx = \int f(x)dx ·\int g(x) dx$$


junit & java : testing non-public methods

JUnit will only test those methods in my class that are public.  How do I do junit testing on the ones that are not (i.e., private, protected)?    I can test them by not using junit, but I was wondering what the junit standard method was.


A person who says that everything in this life is not permanent / is a lie. A person who believes in things only after he has seen/experienced them.


I have a script that works well when I ssh to the server to execute it myself, but has problems when , a continuous integration server, runs it.  I am automating tests on an embedded linux system (the target). The target is connected to Server A (RHEL 5) via serial and operated over minicom. Server B (FC 12) builds the tests that actually run on the target, and can ssh to Server A. Server C (RH) hosts Hudson, with Server B as a slave.   I've written a runscript (http://linux.die.net/man/1/runscript) script to do everything needed on the actual target; it boots the image, mounts a directory from Server B and executes the tests. A bash script on Server B invokes minicom with the runscript script along with some companion actions. I have a bash script on Server B which uses   ssh -t -t ServerA bashScript.sh   to get those tests run on the target. I am on Server C, I can get those tests run by ssh'ing to Server B and executing the script that ssh's to Server A which executes minicom with runscript. Whew.  To review:  Server A: Hudson uses its slave mechanism to ssh to Server B.  Server B: kickOffTests.sh has the line ssh -t -t ServerA runTests.sh  Server A: runTests.sh calls a perl script which invokes minicom -S my.script ttyE1  Target, after booting: Mounts a directory from Server B, where the tests are, and enters that directory. It invokes yet another bash script, which runs the tests, which are compiled C executables.  Now, when I execute any of these scripts myself, they do what they should. However, when Hudson tries to do the same thing, over in the minicom session it complains about a line in the "yet another bash script" that invokes the C executable, ./executable, with ./executable: cannot execute binary file  I still have a lot to learn about linux, but I surmise this problem is a result of Hudson not connecting with a console. I don't know exactly what Hudson does to control its slave. I tried using the line export TERM=console in the configuration just before running kickOffTests.sh, but the problem remains.  Can anyone explain to me what is happening and how I can fix it? I cannot remove any of the servers from this equation. It may be possible to take minicom out of the equation but that would add an unknown amount of time to this project, so I'd much prefer a solution that uses what I already have.


Is it just me or is it a bit illogical that  \documentclass[a4paper]{article} \begin{document} \makeatletter \@ifundefined{chapter}{}{} \makeatother \ifdefined\chapter chapter\else no chapter\fi \end{document}   returns chapter. So basically \@ifundefined actually ends up defining the macro (making it equal to \relax)


Ridge\Lasso -- Standardization of dummy indicators

Say I have a data set with say 5000 rows and about 150 columns (5000 samples, 150 predictors/features) and I'm interested in a applying a ridge or lasso regression. (Let us assume using a logit link function -- if it matters). Again, if it matters, we'll say that some features are highly correlated -- e.g., that more than half of them are actually dummy variable indicators. Let us also say we are more concerned with prediction accuracy than model interpretability (if we wanted a clean interpretation, we would not use a penalized regression!)  Now, the standard recommendation for penalized linear models is to standardize the data (I believe Tibshirani recommends this always. By standardize, I mean center and scale by the mean and standard deviation). However, this will destroy a lot of the structure inherent in the data set. It doesn't make sense to do this I think - since this will lead to what were binary indicators always being present in the model unless Lasso zeroes them out.  Is there a better way to deal with this issue? One could normalize the rows (e.g., Normalizer() in sklearn) which will preserve structure, but in practice this gives me vastly different results.  Should one standardize all inputs? Only non-binary ones? What about ordinal categories (say a column with 1,2,3,... measuring, say, years of education). Normalization or min/max scaling?  Clarification: By standardizing binary inputs, you remove the sparsity in the data set, as you must first subtract the mean. This is what I mean by "destroying the structure".


Removing coincident points with z values greater than minimum

I am trying to run a spline interpolation on some terrestrial LiDAR data, but it keeps failing (I'm getting error 010235 - returned error from spline process and error 010067 - error executing grid expression).  I think it's due to the fact that there may be coincident points (ie. points with the same xy but different z values).   Can anyone suggest a way to delete the duplicate points with z values greater than the minimum? I can't do it manually because I think there may be a lot of duplicates (I tried the collect events tool, and there were many coincident points).


Steepest descent method and how to find the weighting factor

I am trying to understand the numerical method of finding a minimum, the steepest descent method. \begin{equation} x_1 = x_0 - \alpha \frac{df}{dx} \end{equation} I understand the idea behind it and how to set up the equation, but I do not get:   How to find the "right" weighting factor $\alpha$. Why the next search has to occur orthogonal to the previous search direction.   Thanks in advance for the answers.


Undocumented increase in minimum bounty value?

I recently discovered that if I have posted an answer to a question, the minimum bounty I can offer for that question is +100 (instead of the usual +50).   Temporarily deleting the answer reinstates the +50 bounty (a workaround!).  As far as I can tell, this is not mentioned in  , , or . I've also tried  but didn't get very far.  So:   Should the FAQs be updated to include this information? Why have this rule in the first place if it's so easily bypassed?     Update:  This is indeed a new feature (introduced in ) to .This is mentioned explicitly in a few   but, as far as I can tell, not in FAQs. This information is therefore out of reach of mere mortals who do not have a finger on the pulse of MSO/SE.   The loophole mentioned above , but as of this update, can still be exploited (tested on superuser).  We can haz bugfix and faq update, pliz?


how to show output console in GUI using Java Netbeans

Im using netbeans with design (palette). I want to show my output console into GUI in netbeans. So here is my code that I want to execute. I put this to button function, and it works. But I the result show up in output console, I intention to show it in the interface too.  User user = status.getUser();             Date dated = status.getCreatedAt();             PreparedStatement stmt = null;             Connection conne = null;             try {                 Class.forName("com.mysql.jdbc.Driver");                 System.out.println("Connecting to database...");                 conne = DriverManager.getConnection("jdbc:mysql://localhost/jat?useUnicode=true&characterEncoding=UTF-8", "root", "");                 System.out.println(status);                 System.out.println("Inserting records into the table...");                 stmt = conne.prepareStatement("set names 'utf8'");                 stmt.execute();                 stmt = conne.prepareStatement("set character set utf8");                 stmt.execute();                 stmt = conne.prepareStatement("INSERT INTO tweet(ID,date,name,statusLocation,text,source) VALUES (?,?,?,?,?,?)");                 stmt.setInt(1, (int) status.getId());                 stmt.setString(2, getTimeStamp());                 stmt.setString(3, status.getUser().getScreenName());                 stmt.setString(4, user.getLocation());                 stmt.setString(5, status.getText());                 stmt.setString(6, status.getSource());                 stmt.executeUpdate();                 System.out.println("this record inserted!");                 System.out.println("==================");             } catch (SQLException se) {                 se.printStackTrace();             } catch (final Exception e) {                 e.printStackTrace();             }         }         @Override         public void onTrackLimitationNotice(int arg0) {         }         @Override         public void onStallWarning(StallWarning sw) {             throw new UnsupportedOperationException("Not supported yet.");          }     };            FilterQuery fq = new FilterQuery();     double lat1 = 121.300000d;     double long1 = 25.020000d;     double lat2 = 121.380000d;     double long2 = 25.030000d;     twitterStream.addListener(listener);     double[][] bb = {{lat1, long1}, {lat2, long2}};     fq.locations(bb);     twitterStream.filter(fq);}   When the 'run' button executed, the result just displayed in the output console, not in my interface.  And this is my interface look like:   Thank you so much for any reply


How to assign players in MC to a scoreboard team automatically when they join?

I am yet again needing some help with making my Minecraft: Hunger Games map and in order to teleport each player to their podium, I set up a group of 24 command blocks setting them to teleport each team to each podium, for example:   /tp @a[team=P1] x y z, /tp @a[team=P2] x y z   But what I need is something to automatically assign a person when they join the server to a team, but each person must join a different team and I mustn't have two people in the same team. Any suggestions on how I may accomplish this?


How we can solve like this integral $\int \frac{dx}{x^n+1}$ (Hypergeometric function)

In the wolfram given equation $\displaystyle\int \dfrac{dx}{x^n+1}=x\ {}_2F_1\left(1,\dfrac{1}{n};1+\dfrac{1}{n};-x^n\right)$,  But what it's mean? How we can solve without this.


I have just swapped from an Iphone 6s to an Iphone SE. I reset my old phone and and erased all contents and settings but I forgot to remove my icloud account. I've logged on to my icloud account and looked under 'my phone' but all i can see on there is my new phone. When I go into account settings I can see my old iphone 6s and there is an option to remove it from account. If I do this will that mean that my icloud had been removed? Thanks in advance for your help.


I was getting the error     AttributeError: '_RestrictContext' object has no attribute...   with my addon (in Blender 2.72), then I found that access to bpy.context and bpy.data is restricted in addon code, as explained here    Instead of using bpy.context, I can use the context parameter of execute() and invoke(). But what can I use instead of bpy.data?


there is a lot or there are a lot? over here or at here?

I am an English learner. While I was watching a documentary video, this caption really confused me a lot.   Is it correct to say there is a lot? I thought it is supposed to be there are a lot.  Also, what is the difference between over here and at here?


Does it violate copyright law if I include an image of a book page in a question?

When I read a (math or statistics) textbook, sometimes I do not understand some of the equations or proofs in the book. Is it OK to take a picture of the page in the book (or ebook) that has the equations or proofs, and include it in the question as a supplemental matreial? Does this violate any copyright law?


Is it possible to Host single website on multiple server?

I have a file sharing website . It's hosted on a dedicated server which have 16gb RAM and 2tb storage . Now I need more storage and RAM but my hosting service can't provide more than 2tb on single machine . Can I host this site on 2 server with another 2 Tb storage . Will I get 4tb storage for my site . I'm using apache as a server , MySQL for database and php for server side language .


The question timeline indicates when a question becomes a hot network question but doesn't seem to indicate when  it loses  its "hot network question" status, unless a moderator manually removed it from the hot network questions. Where can I see at what time a hot network question lost its "hot network question" status?


I would like to know the derivation of the general equation of a conic:  $$Ax^{2} + Bxy + Cy^{2} + Dx + E y + F = 0$$  I have searched over the internet, but I did not find any resource which doesn't make use of trigonometry.


Reading from an InputStream using read(...)

Just trying to keep the reading as simple as possible. However, the while loop seems to return after 1 loop.  try {    final int SIZE = 512;     byte[] buffer = new byte[SIZE];    int bytesRead = 0;     while(inputStream.read(buffer) != -1) {        bytesRead++;    }     jsonString = buffer.toString();    System.out.println("bytesRead: " + bytesRead + " [ " + jsonString + " ]"); }   It should return something like this:  {"errCode":"7500","errDesc":"unknown"}   But when I get printed out is this:  bytesRead: 1 [ [B@5361bf4c ]   Seems it prints out an memory address or just rubbish.  If I use the following:  inputStream.read(buffer, 0, SIZE);   I get the following:  bytesRead: 0 [ [B@53623578 ]   Many thanks for any advice,


Why does instanceof return false for some literals?

"foo" instanceof String //=> false "foo" instanceof Object //=> false  true instanceof Boolean //=> false true instanceof Object //=> false false instanceof Boolean //=> false false instanceof Object //=> false  12.21 instanceof Number //=> false /foo/ instanceof RegExp //=> true  // the tests against Object really don't make sense  Array literals and Object literals match... [0,1] instanceof Array //=> true {0:1} instanceof Object //=> true  Why don't all of them? Or, why don't they all not? And, what are they an instance of, then? It's the same in FF3, IE7, Opera, and Chrome. So, at least it's consistent.


Alpha and Omega Limit Sets in Polar Coordinates

I guess here I am not sure how to get started, I know the definitions:  The $ω$-limit sets of points are the set of points that the system of equation approach as time goes to infinity, and the $α$-limit sets of points are the points approached as t goes to negative infinity. But I am not sure how the eigenvalues or vectors help me determine the limit sets.  But I don't understand how to apply them.  My conclusion for both of these question is that $α(0)=ω(0)={0}$ because in both cases the origin is a fixed point. Is this correct? Are the more limit sets than these?  Consider the systems of equations and find all the $α$- and $ω$-limit sets of points in the plane.  a.  $$\dot {x}=y+x(x^2+y^2-1)$$  $$\dot {y}=-x+y(x^2+y^2-1)$$  which in polar coordinates, is given by:  $$\dot {r}=r(r^2-1)$$ $$\dot {ø}=-1$$  $$r^2=x^2+y^2$$ $$r \dot {r}=x \dot {x}+y \dot {y}$$ $$=r^2(r^2-1)$$ $$r \dot=r(r-1)(r+1)$$  So I understand how the got the value for $\dot {r}$, but I don't understand how to get the value for $\dot {ø}$  The fixed points will be when $\dot {r}=0$ so when r=1, -1, 0.   From my book: "Because $\dot {ø}$=-1, thus the solution goes clockwise around the origin at unit angular speed." Why??   b.  $$\dot {x}=y+x(1-x^2-y^2)(x^2+y^2-4)$$  $$\dot {y}=-x+y(1-x^2-y^2)(x^2+y^2-4)$$  which in polar coordinates, is given by:  $$\dot {r}=r(1-r^2)(r^2-4)$$ $$\dot {ø}=-1$$


What counts as a 'player kill' for purposes of mob loot/XP?

...other than obvious - sword, bow, punching.  For example, the  has an entry on Zombie Pigman:     Rare drops      2.5% chance to drop a gold ingot if killed by a player      8.5% chance to drop their golden sword when their death is registered as a player kill.      The chances of each can be increased by 1% per level of Looting.      Experience      Zombie pigmen drop 5 experience (12 if baby), when their death is registered as a player kill.   I know there exist pigmen-based XP farms that don't involve the player attacking any pigmen directly. So what sort of deaths count as 'player kill' for the purpose of loot/XP drop? - at least from the more common/practical ones... I'm well aware there are hundreds of ways one can kill a mob.  (if you have the extra knowledge about how these affect pigmen hostility; in particular if any drop XP but don't make zombie pigmen hostile, that would be a nice addition to the answer.)


How to verify if the client files are the same as the server files?

In a client-server game architecture, what are the possible ways to verify that the client has not modified things like gfx assets or client side scripts?  Obviously no solution is perfect, but I would love to hear some ideas.  I am thinking something like an hash on all the files in the resources directory. Does that sound feasible?


I just upgraded from 12.04 to 14.04. Now any Arabic text is displayed as squares, as shown in the image below. I tried installing the Arabic language pack but this did not solve the problem.


This is returned as the last row, the group record ID looks cut off Group_Member__c:{Id=a181K000005jd11QAA, Contact__c=0031K00002tTqaQQAS, Group__c=a171K00000  Query is             list<group_member__c> gmm = ([SELECT id, contact__r.mobilePhoneString__c, group__c from group_member__c where (is_sms_group__c = true and status__c = 'Active')]);         system.debug(gmm);    Maybe the ID is correct and the discrepancy is at system.debug? Edit - just realized the query isn't returning all of the records I need. Double-checked data by creating an equivalent report. Very weird


Ok so this is the first time I am answering my own question. I am doing this because I have (until recently) really struggled with this and could not - for love nor money - find a solution online.  I like the 'standard' integral signs (given by \int, and more importantly, the 'standard' double integral signs (given by \iint in LaTeX using the amsmath package. A long time ago, I was creating a document and used these signs (no problem so far). However, a few weeks pass and I suddenly realise that, without my knowledge, all of the double integral signs have changed from the standard ones, to the shorter straight ones:    I had no idea how to reverse the effects or how they came about in the first place.  As it turns out (which I found out only recently) the wasysym package is to 'blame'. Unfortunately, this is really quite a useful package as it turns out. So I had no solution and just accepted that my document will not look as nice as it should. Oh well.  More recently I had the same situation with a new document, but this time I knew a little more about LaTeX so I thought: "No! I am going to solve this problem if it takes me all night!". Well it didn't... it actually took me nearly no time at all.  I simply used the \renewcommand command, changing \iint to mean \int\int.  My Question: Is there a more elegant way of doing this? I have not encountered a problem with my solution as of yet, but I am aware it is a bit of a cheat's way out.


How to find root of derivative of any polynomial/equation?

Let   $$f(x) = (x-1)(x-2)(x-3)(x-4)(x-5),\quad -\infty< x<\infty.$$   The number of distinct roots of equation   $$\frac{d}{dx}f(x) = 0$$   is exactly ?     The only method that I know is to multiply and then find the derivative of function then apply Sturm's theorem but it seems vague when you have to solve the question in 3 to 5 minutes . So you are requested to suggest a plausible alternative approach.


Calibrating/Correctly draining an Extended Battery

I recently purchased an extended battery for my ailing Galaxy S4. It's supposedly rated at 4000 mAh over the previous 2600 mAh OEM battery.  First time I threw it in, I turned on the phone, chucked in the battery, and sat it on the charger for an hour or so.  It actually lasted a pretty long time. About 2 days and 5/6 hrs. SoT (not fantastic for 4000 mAh, but it's new so what the heck).  So, listening to the advice of others, I threw it on the charger until completely topped off while the phone was shut down. Again, I discharged it from 100%. However, this time, the battery drained much faster than usual. There weren't any particular apps draining the battery, it just drained faster.  Seeing as this was strange, I drained it to 0%, and charged it back up. Still, the same terrible battery drain. It may be I have to cycle it a couple more times.  Advice? How should I correctly calibrate an extended battery?


Bibliography style for BibLaTeX similar to BibTeX+Beamer

I pretty much like how the bibliography is rendered via BibTeX+Beamer as demonstrated by the Metropolis beamer theme:    Does there exist some BibLaTeX style with a similar look and feel? In particular I like the separation/newline between author, title, and remaining parts.


In the admin area, to create a custom block, I go to:  Structure, Block layout, + Add custom block.   Once I create the custom block in the UI, I see a textarea field called "Body" where I can enter content.  How can I dynamically render the node author's name and profile picture in my custom block. I know I can type it in, but I would like to be able to insert some code (PHP, Twig or token) so that it pull's the author's name and profile image dynamically and prints it on the block. I do not want to use a views block, but a custom block instead.


c# parameter passing in ref with class field

I want to swap the field in the ConvexHull class just like swap( points[0], points[1] ).  How do I have to do?  public class ConvexHull {     List<Point> points;      public void run ()     {         Point.swap ( ref points[ 0 ], ref points[ 1 ] );  //Error!!     } }  public class Point {     private double x, y;      Point () { x = y = 0; }     public static void swap(ref Point a, ref Point b) {         Point c = a;         a = b;         b = c;     } }


What does a sound of infinite Hz sound like?

Say an airplane flies at Mach 1. The doppler effect causes the front of the sound emitted by the plane to reach infinite frequency:    $f = \left ( \frac {343+0}{343-343} \right ) f_0 = ∞$  If the plane suddenly stopped, and there was an observer in front of the sound waves to receive the sound, what would the bunched up waves sound like to the observer? Would they cancel each other out and cause no sound?


How do I migrate an SVN repository with history to a new Git repository?

I read the Git manual, FAQ, Git - SVN crash course, etc. and they all explain this and that, but nowhere can you find a simple instruction like:  SVN repository in: svn://myserver/path/to/svn/repos  Git repository in: git://myserver/path/to/git/repos  git-do-the-magic-svn-import-with-history \ svn://myserver/path/to/svn/repos \ git://myserver/path/to/git/repos   I don't expect it to be that simple, and I don't expect it to be a single command. But I do expect it not to try to explain anything - just to say what steps to take given this example.


What is the best way to stop people hacking the PHP-based highscore table of a Flash game

I'm talking about an action game with no upper score limit and no way to verify the score on the server by replaying moves etc.   What I really need is the strongest encryption possible in Flash/PHP, and a way to prevent people calling the PHP page other than through my Flash file. I have tried some simple methods in the past of making multiple calls for a single score and completing a checksum / fibonacci sequence etc, and also obfuscating the SWF with Amayeta SWF Encrypt, but they were all hacked eventually.  Thanks to StackOverflow responses I have now found some more info from Adobe -  and  - which I think I can use for the encryption. Not sure this will get me around CheatEngine though.  I need to know the best solutions for both AS2 and AS3, if they are different.  The main problems seem to be things like TamperData and LiveHTTP headers, but I understand there are more advanced hacking tools as well - like CheatEngine (thanks Mark Webster)


Alternative Slick/Smart method to disply Recursive Replying Comments?

I want to avoid the classical way of replying into replying into replying that goes like this      Comment     --> Reply 1     --> Reply 2     ---->Reply 3     ---->Reply 4     ------->Reply 5     ---->Reply 6   I will be expecting lots and lots of replying levels and the horizontal space is limited.  So I am looking for any good alternatives to that matter. Any ideas?


I read on Wikihow that when you double batch that you should multiply seasonings times 1.5, then adjust to taste. Similarly for alcohol, multiply by 1.25.  I am writing a story in which one character is making a triple batch of baked macaroni and cheese. What would the multipliers for seasonings? What if my character makes a recipe involving alcohol?


Prevent elevation (UAC) for an application that doesn't need it

Having recently migrated from Vista 32bit to Windows 7 64bit, one of my programs now requires admin rights.  I use a rather exotic text editor (Crimson Editor). Although not designed for Vist/Win7 it worked well with Vista. But under Windows 7, the program executable gets this UAC shield added to its icon (even though the "Run as administrator" flag in the compatibility tab is not set) and prompts for elevation whenever I run it.  How does Win7 determine that this notepad-like application needs admin rights? How can I override this false heuristic?


How to prove the Lipschitz property and convergence of infimal convolution functions?

Here is my problem.  Suppose $f:\mathbb{R}^n\rightarrow \mathbb{R}\cup\{+\infty\}$ is a positive function. Define $f_n(x)=\inf \{f(y)+nd(x,y):y\in \mathbb{R}^n\}$. Prove that $f_n(x)$ is Lipschitz continuous and $f_n(x)\rightarrow f(x)$.  I find $f_n(x)$ are increasing, $f_n(x)\leq f(x)$ and for each $n$, $f_n(x)$ is upper semi-continuous  without using the condition $f\geq 0$. I wonder how this condition make sense. Thanks~


What is the difference between currying and partial application?

I quite often see on the Internet various complaints that other peoples examples of currying are not currying, but are actually just partial application.  I've not found a decent explanation of what partial application is, or how it differs from currying. There seems to be a general confusion, with equivalent examples being described as currying in some places, and partial application in others.  Could someone provide me with a definition of both terms, and details of how they differ?


If $x\equiv  a\pmod{n}$, prove that either $x\equiv a\pmod{2n}$ or $x\equiv a+n\pmod{2n}.$  Well I am a bit stuck in this congruence problem. I tried out :- $n\vert x-a$ so for $2n|x-a$, $x-a$ must be even but I am not able to prove what if $x-a$ is odd, how can I prove that $x-(a+n)$ will be even and divisible by $2n$. Is this the right approach? Though it seems a very vague one, I can't think of any other.


Attorney at law, is there any other kind?

I have wondered from time to time about the phrase "attorney at law." Are there other kinds of attorneys? Attorneys at arms? If not, why do we specify?


What happens to unregistered users' comments/answers after migration?

Recently a question of mine was migrated from unix.se to SO. After a few hours I noticed that all answers and comments from a given user had disappeared (there were only 3 or 4 users who contributed). I could be wrong but I don't think he is registered on SO.  What happens to comments and answers from a user registered on site A but not on site B when a question is migrated from site A to B?  He may have deleted them himself (I don't know why he would have), in which case it's moot, but if SO deleted them, that kind of stinks because they were valuable comments (and also added context to some conversation).


Do we have to update everytime using 'sudo apt-get update'command whenever we install anything?

Whenever I am installing anything through the terminal, the provided code includes sudo apt-get update (to update the local repository catalog), but do we have to run the command each time we install something? Does the catalog really get updated so quickly??  This is a different question because I am asking whether I have to use the command before every install.  I am not asking what it means since I know what it means, but I don't understand the necessity of updating it every single time.


What is the difference between would not and did not?  For example:     I called my girlfriend but she wouldn't stop.   I called my girlfriend but she didn't stop.


I'm using the acronym package. Normally, if I enter an acronym like this:   This is a system with \ac{LTI} propertiesSystem. It can be ...   The pdf shows something like this:      This is a system with linear, time invariant (LTI) properties. It can be ...   But I would like to have something like this:     This is a system with LTI (linear, time invariant) properties. It can be ...   How can I set up the acronym package to put the brackets around the description and not around the acronym?  edit:  I tried now using this self defined command:  \newcommand{\A}[1]{\acs{#1} (\aclu{#1})}   It shows the acronym first and the long version in brackets. But if I use the same acronym later, the full description ist shown again and again. I would prefer, that it is shown just the first time...


Selecting or pasting image with certain aspect ratio cause it to get out of the box

When uploading image and selecting an image to insert (or dragging/pasing), a preview of the image is shown in the Uploader modal, before "Add picture" is clicked.  For some images, the preview breaks out of the modal's dashed box, e.g.        Possible fix might be changing the CSS rule on:  .modal.image-upload .modal-dropzone-default, .modal.image-upload .modal-dropzone-preview   From:  height: 246px;   To:  min-height: 246px;


Is there any Possibility to reset the partitions after installation

I installed Ubuntu 16 on a 8GB pendrive (Bootable Drive) and created two partitions for Ubuntu(Ext4 - 6000MB, Swap - 2000MB). I want to resize the partitions without re-installing the Ubuntu. Is there any possibility???


URL redirection from 'More site stats on' link in Beta sites

In every beta site, we usually see the Site Stats side bar in the right hand side, at the end of side bar there is link for more stats in Stack Exchange site. For an example: In  when hover the link it shows the URL as , click on that it will redirect to Stack Exchange All sites page.  But what is the use of the #health at end of the URL, it is expected to highlight the Health beta in the All sites page? or some other purpose?


I am trying to store objects of inherited types into a std::deque array.  I succeed to store the elements, but when I try to use them, only the parent properties are preserved.  enum Family { parent_, child_};  class Parent {  public:      double a;      Family type;      Parent(double a_, Family type_=Family::parent_) {         a = a_;         type = type_;     }      void print() {         std::cout << "I am the parent. a:" << a << std::endl;     }  };   class Children: public Parent {  public:      double b;     double c;      Children(double a_, double b_, double c_) : Parent(a_, Family::child_) {                 b = b_;         c = c_;     }      void print() {         std::cout << "I am the children. a:" << a << ", b:" << b << ", c:" << c << std::endl;     } };   void class_inheritance_test() {      std::deque<Parent> vec;      vec.push_back(Parent(1.0));     vec.push_back(Parent(2.0));     vec.push_back(Children(10.0, 20.0, 30.0));      for (Parent &e : vec)         if (e.type == Family::child_){             Children* ch = static_cast<Children*>(&e);             ch->print();         } else {             e.print();         }        }   The output of this piece of code is:  I am the parent. a:1 I am the parent. a:2 I am the children. a:10, b:0, c:-1.30018e-231   Clearly, when I cast back the Children from its storage as a Parent, the properties defined in the Children class are lost.  I see that the problem is either in the way I store the objects or in the way I cast them back to the class they are supposed to be.  I would appreciate some guidance on how to store objects of multiple types in a vector and be able to use them back.  The other examples I have seen do not include properties, and for my problem I must have properties.  EDIT ------------------------------  For those in the future, the solution is to use shared_ptr:  void class_inheritance_test() {      std::deque<std::shared_ptr<Parent>> vec;      vec.push_back(std::make_shared<Parent>(1.0));     vec.push_back(std::make_shared<Parent>(2.0));     vec.push_back(std::make_shared<Children>(10.0, 20.0, 30.0));      for (std::shared_ptr<Parent> e : vec)         if (e->type == Family::child_){             std::shared_ptr<Children> ch = std::static_pointer_cast<Children>(e);             ch->print();         } else {             e->print();         }        }   The output is exactly what is expected:  I am the parent. a:1 I am the parent. a:2 I am the children. a:10, b:20, c:30


How to change or add location to pictures in new Photos app on OS X?

Since I updated my iPhoto to new Photos App from Apple, I cannot find where to change or add location information to pictures. I had a rich collection of places in my iPhoto.


I'm using Ubuntu GNOME 16.10 and was trying to install WPS Office. I tried to install using software centre But it wasn't installing without giving any error logs. Then I opened it with Gdebi installer. Here is what I saw.    I have already trying enabling multiverse repositories.  Edit: I have downloaded the amd64 package from the WPS official site, but even now installing through terminal I still get the missing dependencies error.


What is the simplest way to capitalize first letter of every sentence in LaTeX?

I have been working in LaTeX for a while, and during the typing I noticed that many places I skipped pressing the Shift key to make the first letter of a sentence capital. After checking here and there on internet, I found that LaTeX doesn't have any option to do that automatically and there are some macros etc which can do, but I want to know if there is any simple way to do it. Especially when you have a report of hundreds of pages and finding each one is a bit hard to manually update to a capital letter.  MS Word does it automatically.


My father died Jan 12th and no social security payment was posted to his bank account in Jan.& directly deposited on Feb. 4th.  Does that money belong to his estate or will the dept. of social security take it back?  Is social security paid in arrears?


What ability modifier, if any, would apply to a firearm attack roll?

I'm playing D&D 5e, and I'm not sure what ability score applies to firearm attack rolls. (Using the stats from the DM's Guide.)


Change animation fps at certain times (i.e. slow down the animation for a moment)

What I want is to fly by an object, and once we are really close to it, slow down time to give a nice look (animation of the objects in the scene is also slowed down) and then move on.  What this basically boils down to is this: we should have less frames per second at the 'slowed down' moment (less frames passing by in the same time means that the animation passes by slower) and then increase the fps afterwards.  Now, how do I do that? Or are there other ways to do it easily?


If a ball carrier falls to the ground, how many seconds will the umps allow the clock to run?

If a ball carrier falls to the ground, and the other team wishes to run the clock because they are leading, how many seconds will the umps allow the clock to run?


Have to click on triangle to view reputation breakdown

Have a look at .  To expand / collapse each day to show / hide the breakdown, you have to click the triangle. However, wherever you hover on the line you get the hand cursor, suggesting you can click.  Please can we be able to click anywhere on the line?


Please guide me to draw this : graph of $x \geq 5$ and $y \geq 5$

how can I draw the graph for this   the graph of $x \geq 5$ and $y \geq5$ is?  please guide me to draw it   thanks in advance


What is the result of unpacking with * or **?

What is the result of unpacking? I thought the unpacking result is a first class citizen that I can use as an object. >>> print(*range(5)) 0 1 2 3 4  However, apparently it cannot be evaluated to be an object and I cannot get its type. So, I wonder what is the unpacking operation generating? >>> *range(5)   File "<stdin>", line 1 SyntaxError: can't use starred expression here  >>> type(*range(5)) Traceback (most recent call last):   File "<stdin>", line 1, in <module> TypeError: type() takes 1 or 3 arguments  >>> *values, = 1,2,3  >>> values [1, 2, 3] >>> *values   File "<stdin>", line 1 SyntaxError: can't use starred expression here


What is the source of Earth's magnetic field?

I saw on Discovery channel that the source of Earth's magnetic field is the molten iron and metals in the earth's core. The spinning of these liquid metals produces the same effect as electric current in a coil which produces a magnetic field. The scientist in the program proved the concept by conducting an experiment where a big metal sphere where winded by a metallic tube in which molten Sodium was pumped so it circulate around the sphere in a similar way that happens inside earth. The experiment showed that a magnetic field was successfully produced.  My question is :  How could a circulating neutrally charged particles produce a magnetic field?  It is like having two electric currents one due to the negative charges (electrons) and the other is due to positive charges (nucleus) with same value and in opposite direction so there should not be a magnetic field. so how does this happen?


Uses of "have you had" and "did you have"

When to use have you had and did you have in sentence?  e.g.  1) To ask some if he had his lunch or not?  Have you had your lunch?  Or  Did you have your lunch?  2) To ask some if he faced this situation in past or not?  Have you had this situation when you were doing this?  Or  Did you have this situation when you were doing this?


check/uncheck all or some checkboxes with javascript or jquery?

I have a page where I have a form at the top of the page that a user can select certain cities to filter on. So far it looks like this:    <?php    $start=_GET['start'];  $end=_GET['end'];   if(empty($start)){    $start=date("Ym"); } if(empty($end)){ $end=date("Ym");  }   $places=array(); if(!empty($_GET['cities'])){   foreach($_GET['cities'] as $loc){ array_push($places,$loc);  } }else{  $places=('CHI','DET','LA','NYC','DAL','SPR','PHI','PITTS','HST','KMZ','SCR','BUF','ALB','UTI','DEC','QNC','SNF');  }  ?>  //html <form method='GET'> START:<input type='text' name='start' value= '<?$start?>'> END: <input type='text' name='end' value='<?$end?>'> <input type='checkbox' name='cities[]' value='CHI' <?= (in_array('CHI', $places)) ? 'checked' : ''; ?> >CHICAGO <input type='checkbox' name='cities[]' value='DET' <?= (in_array('DET', $places)) ? 'checked' : ''; ?> >DETROIT <input type='checkbox' name='cities[]' value='LA' <?= (in_array('LA', $places)) ? 'checked' : ''; ?> >LOS ANGELES <input type='checkbox' name='cities[]' value='NYC' <?= (in_array('NY', $places)) ? 'checked' : ''; ?> >NEW YORK <input type='checkbox' name='cities[]' value='DALLAS' <?= (in_array('DAL', $places)) ? 'checked' : ''; ?> >DALLAS <input type='checkbox' name='cities[]' value='SPR' <?= (in_array('SPR', $places)) ? 'checked' : ''; ?> >SPRINGFIELD <input type='checkbox' name='cities[]' value='PHI' <?= (in_array('PHI', $places)) ? 'checked' : ''; ?> >PHILADELPHIA ......rest of the cities....  <input type='submit' value='Filter'>   </form>   <?  $SQL="SELECT NAME,     ID,     PHONE,     EMAIL,     EVENT,     LOCATION   FROM SHOPPERS  WHERE LOCATION IN ('".implode("', '", $places)."')  AND EVENT BETWEEN '{$start}' and '{$end}'  AND ID BETWEEN '25687' AND '28050'  ";   //and then fetch array to print out results... ..... ?>   This works just fine now. As soon as the page loads, all the cities are checked and the user can check/uncheck whatever they want. However, now, I want to add some boxes/buttons right above the cities with the state names in them, so that if I just want to filter on cities in Illinois, I can click/unclick that and it would check/uncheck Chicago, Decatur and Quincy. I also want to put two new buttons, one to select all and one to clear all.  So the two new buttons would look something like this:    <input type="button" class="check" value="Select All" />   <input type="button" class="check" value="Clear" />   Any help? Thank you


How to prove $\lvert \lVert x \rVert - \lVert y \rVert \rvert \overset{\heartsuit}{\leq} \lVert x-y \rVert$?

I'm trying to show that $\lvert \lVert x \rVert - \lVert y \rVert \rvert \overset{\heartsuit}{\leq} \lVert x-y \rVert$. A hint would be nice.


To prove this sequence does not contain a perfect square

I have to prove that the sequence $\{11,111,1111, \dots \} $ doesn't contain any perfect square numbers. I can realize it but I am unable to prove it. Please help.


Is $\lim_{n \rightarrow \infty} a_{n+1}/a_n=L \implies \lim_{n \rightarrow \infty} \sqrt [n] {a_n}=L$ true? If not, is there a counter example?

We were told, in recitation class, about a test for sequences convergence (not series) Which goes as follows:  if $\lim_{n \rightarrow \infty} \frac{a_{n+1}}{a_n}=L$ then $\lim_{n \rightarrow \infty} \sqrt [n] {a_n}=L$.  In a previous question I asked:    I was told that this fact is not true. My question is, can anyone think of a counter example for it? Because, If yes, Then I would like to let my tutor know about it, but, I don't want to doubt him befor I am sure of it.  Thank you!


Should I use plural noun after ''both'' in the sentence below?

Set the Max depth parameter of both the Reflection and Refraction roll-out to 10. I am not sure whether roll-out should be plural or not in this particular case.


Is an infinitely-long integer in the natural numbers?

Say you constructed a number by counting out the positive odd numbers, in sequence:  $\{1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55...\}$  $135791113151719212325272931333537394143454749515355575961636567697173757779...$  This number would clearly be infinitely long, as there are an infinite number of odd numbers to choose from. Would this number be considered a natural number?  Follow-up:  If this number is not natural, what specifically disqualifies it? It certainly appears on the number line, just infinitely far from the origin, and it is a whole number. Moreover, which of the basic sets is this number a member of, and why?


Finding the number of ways to make change for a given amount

I want to find the number of ways to make change for $22.22 using pennies, nickels, dimes, quarters, half dollars, and dollars. I have a textbook with generating functions for this, but I don't exactly see what to do.


How to return two values of same datatype from a single function in java?

I want to return two values from method which is used to get input from the user and after getting input I haev to return those values in another method as a parameter/argument. i tried to use "return a,b" but its not working. please suggest me the solution.... ` public static int fnInput(){     Scanner sc1 = new Scanner(System.in);      System.out.println("Enter 1st Number:");     int a = sc1.nextInt();      System.out.println("Enter 2nd Number:");     int b =  sc1.nextInt();          return a,b;  } ` I tried to use this array method too but this method is also not working and returning the values ` public static int fnInput(){     Scanner sc1 = new Scanner(System.in);      System.out.println("Enter 1st Number:");     int a = sc1.nextInt();      System.out.println("Enter 2nd Number:");     int b =  sc1.nextInt();          return new int[] {a ,b };  } `


Boot Camp partition broken and can't be repaired in OS X 10.10.4

Suddenly my Boot Camp partition vanished: not visible in Finder, not visible on startup. In Disk Utility I can see the volume, but it's broken (verification log):  Verifying volume "disk0s4" Verifying file system. ** /dev/rdisk0s4 Invalid BS_jmpBoot in boot block: 2b0601 File system check exit code is 8. Error: This disk needs to be repaired. Click Repair Disk.   …and cannot be repaired:  Verify and Repair volume “disk0s4” Repairing file system. ** /dev/rdisk0s4 Invalid BS_jmpBoot in boot block: 2b0601 File system check exit code is 8. Updating boot support partitions for the volume as required. Error: Disk Utility can’t repair this disk.  Back up as many of your files as possible, reformat the disk,  and restore your backed-up files.   Before there was another message, something about   Mount of disk0s4 blocked by dissenter.   Terminal's diskutil list command:  #:                       TYPE NAME                    SIZE       IDENTIFIER 0:      GUID_partition_scheme                        *1.0 TB     disk0 1:                        EFI EFI                     209.7 MB   disk0s1 2:                  Apple_HFS Macintosh HD            596.5 GB   disk0s2 3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3 4:       Microsoft Basic Data                         199.3 GB   disk0s4   and another one:  sudo gpt -vv -r show /dev/disk0  gpt show: /dev/disk0: mediasize=1000204886016; sectorsize=512; blocks=1953525168 gpt show: /dev/disk0: Suspicious MBR at sector 0 gpt show: /dev/disk0: Pri GPT at sector 1 gpt show: /dev/disk0: Sec GPT at sector 1953525167      start        size  index  contents          0           1         MBR          1           1         Pri GPT header          2          32         Pri GPT table         34           6                 40      409600      1  GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B     409640  1165055256      2  GPT part - 48465300-0000-11AA-AA11-00306543ECAC 1165464896     1269536      3  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC 1166734432   397446048         1564180480   389343232      4  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7 1953523712        1423         1953525135          32         Sec GPT table 1953525167           1         Sec GPT header   Once, I had as similar problem after partition resizing and had successfully solved it with this guide. But here I see some differences - now naming is not detected and you can't see BOOTCAMP in Finder sidebar. So, I'm not taking chances and won't follow  until someone will advise me so.  iMac14,3 (21.5-inch, Late 2013) , OS X Yosemite (10.10.4)  Here is sudo fdisk /dev/disk0  Disk: /dev/disk0    geometry: 121601/255/63 [1953525168 sectors] Signature: 0xAA55      Starting       Ending  #: id  cyl  hd sec -  cyl  hd sec [     start -       size] ------------------------------------------------------------------------  1: EE    0   0   2 - 1023 254  63 [         1 - 1564180479] <Unknown ID> *2: 07 1023 254  63 - 1023 254  63 [1564180480 -  389343232] HPFS/QNX/AUX  3: 00    0   0   0 -    0   0   0 [         0 -          0] unused        4: 00    0   0   0 -    0   0   0 [         0 -          0] unused


What is the quotient of a cyclic group of order $n$ by a cyclic subgroup of order $m$?

Suppose that $H$ is a (cyclic) subgroup of order $m$ of a cyclic group   $G$ of order $n$. What is $G/H$?   It's a very simple question but I am still struggling with getting accustomed to the notion of the quotient group.   Now, I know that $m$ divides $n$ and that $G/H$ will be a group of cosets such that $\{gH:g\in G\}$. As a result, there will be $n/m$ of such cosets. I was wondering I can say anything more specific than just that?


How to delete a class from production using destructiveChanges.xml

Can any one tell me the steps to delete a class using destructiveChanges.xml


Drawing a large binary matrix as colored grid in TikZ

I have a pretty big binary matrix of maybe 70 rows and 64 columns. For ease of viewing, I would like to draw this matrix in TikZ where e.g. a 1 is represtented by a red square and a 0 is a white square. Does anyone have any idea how I could obtain this?  Ideally, I would have something where I can just load the matrix from a file and TikZ would handle everything else. Otherwise, I am also happy with a solution having to do find/replace every 0 by some string, and replace every 1 by another string.  Thank you in advance!  Example matrix:  10110101010 10010101010 01010111010 11110010100 01100011001 11101010111 10101010111


I trying to remember the name of a book I read 20 or 30 years ago. A man is stranded on an alien world.  He gets badly injured and a bug like alien heals him by creating a organic heart.  The aliens are solar powered and must wall themselves off at night for protection from predators. All their technology is based on organics.  The human shows them a battery and they are able to modify their bodies to have organic batteries and stay awake at night.


I have to find a splitting field of $x^{6}-3$ over $\mathbb{F}_{7}$

I want to find a splitting field of $x^{6}-3$ over $\mathbb{F}_{7}$. I learned that Finite field containing $\mathbb{F}_{7}$ is the form of $\mathbb{F}_{7^m}$ and it is normal extension. So I've tried to find smallest m containing a single root of $x^{6}-3$. If  $x^{6}-3$ is irreducible in $\mathbb{F}_{7}$, then $\mathbb{F}_{7^m}$ is splitting field of  $x^{6}-3$. But I don't know where I should start. Even, I cannot prove that $x^{6}-3$ is irreducible. For polynomial of degree less than 3, there is a method to determine whether it is irreducible or not. But this is not the case. And the try using Gauss' Lemma and Eisenstein is failed, because I cannot find ring $R$ of which field fraction is $\mathbb{F}_{7}$. Is it wrong approach for this kind of question?


Can't load GRUB all of a sudden (UEFI problem)

So, the last time I used my Ubuntu installation was last night. Today, as I booted it up, it told me that booting grubx64.efi is not allowed. Easy enough. I know how to re-enable it from my BIOS.  After re-enabling it, I try booting again and get the following error:     error: Secure Boot forbids loading module from (hd0, gpt7)/boot/grub/normal.mod   And then there's this some kind of 'grub resuce' CL prompt below that error. Never figured it out except that ls is a valid command. Using ls displays various (hdx , *) files/directories/drives.  Note that, as I never got to load Windows 8 from GRUB despite various tutorials, I use rEFInd to switch between loading GRUB (which, in turn, I use to load Ubuntu) and Windows 8.  How do I re-enable GRUB (and get to Ubuntu) and does anyone know what just caused this problem? I remember installing Ubuntu updates last night but I can't remember if there was anything that might relate to something UEFI-specific.


Prove that there is no non-zero linear operator on $\mathbb C^{2}$ such that $(\alpha | T\alpha) = 0$

I'm stuck on this problem for a long time. I can't find a proper solution for this without using complex calculations. I hope some one can help me with this problem:          Let $ (\;|\;)$ be the standard inner product on $\mathbb C^{2}$. Prove that there is no non-zero linear operator $T$ on $\mathbb C^{2}$ such that $(\alpha|T\alpha) = 0\;$ for every $\alpha$ in $\mathbb C^{2}$. Generalize.


Quantum Stat-Mech Proof of an Inequality for the Partition Function

I have the following problem that I was unable to solve for class, but I had a couple first steps that I started with that I am unable to finish.  I know I can't get this since it's already been turned in, but I would like to see if this was even a viable option for doing this proof in the first place.  ``Given an orthogonal set of states, $\{\phi_{n}\}$, and a Hamiltonian, $\hat{H}$, show that the partition function, $Q_{\beta}$, satisfies the following $$ Q_\beta \geq \sum_{n}\exp\{-\beta \langle \phi_n|\hat{H}|\phi_n\rangle \}$$ with equality holding when the $\phi_n$ states are eigenstates of the Hamiltonian.''  I started by dropping in the identity in the exponential (as eigenstates of the Hamiltonian) $$ \sum_n \exp\{ -\beta\sum_k \langle \phi_n|\psi_k\rangle\langle \psi_k |\hat{H}|\phi_n\rangle\}=\sum_n \exp\{ -\beta \sum_k E_k |c_{nk}|^2\}$$  Then I am left with showing that $$\sum_n \exp\{ -\beta \sum_k E_k |c_{nk}|^2\} \leq \sum_k \exp\{ -\beta E_k\}$$ with equality showing up again the same way, with a Kronecker delta $\delta_{nk}$ collapsing the sum in the exponential.  I realize I didn't make it very far, so this might not be the best way to show this, but it seems manifestly true just by looking at it, but I can't actually show it.  Does anyone have any hints about how to continue with this?


Should answers that can attribute severe legal consequences be discouraged?

Context:   The  may be the ethically correct thing to do, but there's certainly legal ramifications with it that should not be ignored. While the answer has a bolded disclaimer that points this out, this doesn't change the fact that the content of the answer itself can cause serious harm.  Should such answers be discouraged on this site? Should they be redirected to Law.SE?


Combine flag and edit queues from main and meta on SE 2.0 sites

Abstract  There's no need to have two flag queues (one for meta, and one for main) for moderators to check.  There's also no need to have two edit queues, if suggested edits were allowed on meta sites.  We should have one flag queue and one edit queue for both main and meta SE 2.0 sites.  Background  Most of these sites have a low traffic level and low participation.  How low traffic are they?  Moderators get pinged in their global inbox for questions on Meta sites because we're desperately trying to make sure that any traffic is successful.  Our meta traffic is picking up rapidly, but it's nowhere near the point that it's sensible to check meta's  flag queue.   The Problem  The flag and edit queues are currently separate on the meta and main sites.  This reduces the flag handling time, and is yet another queue for mods to check.  The undesirability of a separate edit queue is used to justify the  on meta sites.   The Solution  The flag queue on meta should be integrated with the main site flag queue.  Additionally, suggested edits should be implemented on meta, and this queue integrated with that of the main site.


Ordinal regression with categorical covariates and predictors

I am trying to do an ordinal logistic regression (ordinal outcome variables with more than 2 categories) with nominal (more than 2 categories for some) predictor variables, as well as nominal (more than 2 categories for some) covariates/moderators.  First of all, I would like to test for effect interaction to see which of my covariates/moderators are indeed moderators so that I can treat them as such.  Second of all, I would like to know what's the best way to come up with the optimal model? Do I need to do dummy variables for the covariates? Can I do a stepwise for ordinal regression?


How do calculators calculate the value of trigonometric functions?

I have an obsession about trig functions. I find them to be so mysterious, because I really don’t understand calculus (other then trying to make sense of it in a few YouTube videos, which doesn’t work for me).      Anyhow I was wondering if someone can explain how calculators find the ratios for sine and cosine by just typing in the degrees.   This seems impossible to me from a logical standpoint. I don’t see any pattern other then as the angle increase the ratio for cosine gets exponentially smaller. If anyone can tell me how you get an exact number for something that has no pattern, please explain it to me in the simplest possible way.  Pretend you're explaining it to your 10-year-old child.  I am very visual so anything with pictures would work. If you start getting into Taylor series with calculus, I won’t understand.  I’m basically looking for a simple explanation of what the calculator is doing without getting deep into the math.  Thanks in advance.  Cheers


$\chi^2$ distance and multivariate gaussian distribution

I want to know how to write the $\chi^{2}$ distance between two multivariate Gaussian distributions $f$ and $g$ in terms of their parameters only. The parameters of $f$ is the vector $\mu_{1}$ and a covariance matrix $\Sigma_{1}$. The parameters of $g$ is the vector $\mu_{2}$ and a covariance matrix $\Sigma_{2}$.


what is the difference in the usage of the following?

What is the difference in the usage of "whom" and "who"? please also tell me the rules behind their usage and some examples to clarify their difference.


Let $D := \{z \in \mathbb{C}: |z| < 1\}$ and $f\colon D \rightarrow \mathbb{C}$ be holomorphic. Suppose $\lvert f(z)\rvert \leq 1$ on $D$, show that $$\frac{|f(0)| - |z|}{1 + |f(0)||z|} \leq |f(z)| \leq \frac{|f(0)| + |z|}{1 - |f(0)||z|} \ \forall z \in D.$$  I have tried using Cauchy Integral Formula to $f$ and expanding $f$ at $0$, but I have no idea why $f(0)$ appears in the inequality in the former case. Both answers and hints are appreciated and thanks in advance!


What Happens When A Gravitational Wave Interacts With Another One?

If two gravitational waves came in contact with each other what would happen? In another question entirely, what happens when a higher gravitational field interacts with a weaker one.


Problem: $f$ is a function from $\mathbb{R}$ to $\mathbb{R}$, here $\mathbb{R}$ is the set of real numbers. $f$ cannot be continuous if $f$ takes every value exactly twice.  Now this question is really old and asked many times before on stackexchange. But every solution is by crude manipulation. I want to know if there exists an insightful solution of this.   My problem: I have solved the problem before like this, first assume the function is continuous and then by applying intermediate value property lead to some contradiction. But if the problem is a more general one, like if the function takes every value thrice, the same argument works, but the solution becomes lengthier. That's why I am asking for some more nice solution, may be using some advanced tools.


I purchased 20 GB extra of storage for my iPad and iPhone on iCloud. But my devices say they are still full. How do I get the storage to show up so I can download an update, apps etc.?


$\mathbb{C}[t]$ is not flat $\mathbb{C}[t^2,t^3]$-module

Let $A=\mathbb{C}[t]$ and $B=\mathbb{C}[t^2,t^3]$. We can naturally regard $A$ as a $B$-module. I want to show that $A$ is not flat $B$-module.   Let $f:A\otimes_B A \to B\otimes_B A,\ x\otimes y \mapsto t^2x\otimes y$.  $f(1\otimes t)=f(t\otimes 1)$, so it is enough to show that $1\otimes t \neq t\otimes 1$ in $A\otimes_B A$. But I can't show it. How to prove it?  Thanks!


How to prove that $\sum_{n=1}^{\infty} \frac{|\sin n|}{n}$ and $\sum_{n=1}^{\infty} \frac{\sin^2 n}{n}$ both diverge?

How can I prove that $\sum_{n=1}^{\infty} \frac{|\sin n|}{n}$ and $\sum_{n=1}^{\infty} \frac{\sin^2 n}{n}$ both diverge?  I thought of using Comparison test, but I couldn't find any sequence to compare with.  This question is from the book 'Real Analysis and Foundations' by Steven G. Krantz.


How to append a scene from an existing .blend file to the current .blend file?

I just want to append a scene (named "fred" which is the ONLY scene in the file) to the existing open blend file. Seems like this should be easy, but I can't find out how to do this. So, after the append there should be two scenes: the orignal one and a new one named "fred".  I know the name and location of the file and the scene I want appended.  Thanks for any help.


The error "there is no line to end here" when using \\~\\ or \newline

When I want to have a space between lines I use \\~\\ or \newline  For example       Hello this is an example      \\~\\     Goodbye   I get the error there is no line to end here.  What am I doing wrong?


What does this $\asymp$ symbol mean? (subject: analytic number theory)

I'm reading a  by Andrew Granville on analytic number theory.  On page 22 of the paper, there appears a strange looking symbol, undefined.  I've circled it in red in the screenshot below.    Since it's not defined in the paper, I'm assuming it must be standard notation.   From the context, I'm assuming it means something like "as compared to", or "with reference to", but that's just a guess.  Can anyone identify the symbol, even better explain what it means and/or provide a reference?  Is there a name to speak the symbol?  Thanks in advance.


I'm sure variations on this come up a lot, but I was specifically interested in a response to a claim made by a particular article:     The article is aiming to disprove the idea that an 'observer' collapsing a wave function has anything to do with consciousness or human observers.  At one point it argues that the reason an electron in the double slit experiment has its wave function collapsed when detected before entering one slit or the other is due to the photons fired at it to detect its position having momentum and physically interacting with it. The author uses the analogy of tennis balls being fired into a dark room and using a tennis racquet to detect them - the method of detection causes a change in their behaviour.  Now in this instance that's all well and good, but firing photons is not the only means of detecting something. In the Schrödinger's cat thought experiment, for instance, a Geiger counter is used. As far as I understand it, these simply detect passively rather than firing out photons with momentum.  I know many people disagree with the wave function collapse theory and prefer decoherence (which I'm still wrapping my head around) but I'm interested to know if this is something that's explained within collapse theory or if it's something that's seen as disproving it.


Which Marvel TV episodes are related to the MCU movies?

I've kept up to date with the movies from the MCU, but I am grossly out of date with the TV series, of which I think there is only Agent Carter (not as relevant for the movies I think, besides that scene in Captain America 2), and S.H.I.E.L.D. (which from what I've seen seems more relevant, with  coming in phase 3).   I've gained what I can from . But I can't tell which of the episodes listed are relevant to the movies (clearly, it seems that none are essential), and which movies are relevant to the episodes.  So which episodes are related?


PCB Design - Polygon pour remove islands or not?

Sometimes a polygon pour (I use Altium, so I am using it's naming reference, for other packages it can be power plane and etc.) makes a dead copper area, and the software gives you the option to remove it or no, but why someone will want to not remove it? The only reason I can think someone will want a dead copper area is to make fabrication faster since there will be less copper to remove, and to make it cheaper since less chemicals will be used.  Is this right? Or there are other options that I cant see? Thank you!


Let $G$ be abelian group and $H=\{ x^{2}/x\in G\}$    $H$ is it a subgroup of $G$ ?   H is subset of a group G is a subgroup if :  (i)$\quad  e \in H$ (e is The identity element of G)  (ii) if $x, y \in H$, then $x\ast y \in H;$  (iii) if $x \in H$, then $x^{-1} \in H.$  indeed,  For  ii) let $x,y \in H$ then $x \ast y=(xy) \in H$  i'm stuck in that level so i can't prove (i) or (ii) true or flase    If H is subgroup of G can i general that  for  $H^{n}=\{ x^{n}/x\in    G\}\quad  \forall n \in \mathbb{N} $


What was the joke that Geordi told Data in TNG: "Encounter at Farpoint"?

states:     Apparently at some point during this mission, Geordi La Forge told Data a joke, which the humorless android did not "get" until years later, when he activated his emotion chip during the events of Star Trek: Generations.    Is it known what the joke is?


How to calculate information included in R's confusion matrix

I want know the formulas for the information highlighted in the confusion matrix in the picture below:


How to access deleted question via data explorer?

Deleted questions only get soft-deleted. They are not shown anymore,   (but accessible to >10k-rep-users). Thus, they should be available   via the data dump.  How would you access, say, ?    It was alleged that this question is a duplicate of .   The duplicate-origin contains the information (in the question, it has no answers) that the data dump does not contain deleted questions, yet  offers deleted SO questions. Thus, it might be possible.


How can I choose good avocados at the supermarket?

I've been trying to ignore my burning desire to make some guacamole because every time I go to the supermarket to buy avocados I can't manage to pick out good ones.  They always either become too soft before I have a chance to do anything with them or are hard and not very tasty.  How can I tell when an avocado is perfectly ripe?


Is it possible to wrap the heading of a column of an attribut table within the print composer?

The "wrap text on" function seems not to work for the heading of the columns, only for the rows.  I'm using QGIS 2.14.4


Hi I using java and testng for my test suite and allure report for reporting , issue is I am not able to figure out how to implement condition where  Blacklist specific header value Logged response only if test case failed.  I am using Listners at class level package testListnersT;  import com.aventstack.extentreports.markuputils.ExtentColor; import com.aventstack.extentreports.markuputils.MarkupHelper; import configurationAPI.BaseConfiguration; import io.qameta.allure.Attachment; import io.restassured.RestAssured; import io.restassured.filter.log.LogDetail; import io.restassured.filter.log.RequestLoggingFilter; import io.restassured.filter.log.ResponseLoggingFilter; import org.testng.ITestContext; import org.testng.ITestListener; import org.testng.ITestResult;  import java.io.ByteArrayOutputStream; import java.io.PrintStream;  public class ListenersT extends BaseConfiguration implements ITestListener {      private final ByteArrayOutputStream request = new ByteArrayOutputStream();      private final ByteArrayOutputStream reponse = new ByteArrayOutputStream();      private final PrintStream requestVar = new PrintStream(request, true);      private final PrintStream responseVar = new PrintStream(reponse, true);       public void onFinish(ITestContext arg0) {         // TODO Auto-generated method stub      }      public void onStart(ITestContext arg0) {         RestAssured.filters(new ResponseLoggingFilter(LogDetail.BODY, responseVar),                 new RequestLoggingFilter(LogDetail.BODY, requestVar));     }      public void onTestFailedButWithinSuccessPercentage(ITestResult arg0) {         // TODO Auto-generated method stub      }      public void onTestFailure(ITestResult result) {         childTest.info(result.getThrowable());         childTest.fail(MarkupHelper.createLabel("FAIL", ExtentColor.RED));     }      public void onTestSkipped(ITestResult arg0) {         // TODO Auto-generated method stub     }      public void onTestStart(ITestResult arg0) {         // TODO Auto-generated method stub      }      public void onTestSuccess(ITestResult arg0) {         logRequest(request);         logResponse(reponse);     }       public byte[] attach(final ByteArrayOutputStream log) {         final byte[] array = log.toByteArray();         log.reset();         return array;     }      @Attachment(value = "request")     public byte[] logRequest(final ByteArrayOutputStream stream) {         return attach(stream);     }      @Attachment(value = "response")     public byte[] logResponse(final ByteArrayOutputStream stream) {         return attach(stream);     }  }  Below is sample test code  @Epic("Entity")     @Story("Service")     @Description("Test Desc")     @Test(priority = 1, groups = {"testOne"})     public void verifyTEST(Method method) {              domainURL = env.apiBaseURL();                       body = JsonBuilderFactory.buildObject()                 .add("id", 12345)                                 .getJson();          response = given()                 .config(config.logConfig(LogConfig.logConfig().blacklistHeader("key")))                 .header("Content-Type", "application/json")                 .header("key", Key())                 .body(body.toString())                 .post(domainURL);         assertThat(response.path("statusMsg").toString()).as("").contains("SUCCESS");     }


Considering all opposing players are on the left side of the pitch, is player 22 offside ? I drew this on paint so please pardon the laziness. Might seem odd as a question but all opposing players are on my side (left side) of the pitch does that not free the player 22 ?


If we have a clause like $$(x,y)$$ and $$(x,\neg y)$$ we can derive empty clause but why do we derive the empty clause and not the empty set? When would we derive the empty set?  My question is regarding the difference between an empty SET and CLAUSE not how to derive them. I know how to derive the clauses above. I was just using a previous question as an example.  For example why do we get the symbol on line 7 while in the other picture we get { } on line 5.


Show that $\lim_{h \rightarrow 0} \frac{a^h-1}{h}$ exists

I want to prove that for $a\gt 0$ and $h\in \mathbb{R}$ the  $$\lim_{h \rightarrow 0} \frac{a^h-1}{h}$$ exists. There is no point of definition for a since it is just a real number greater $0$. Since this problem is set in the context of school and the students do not know the $\log$ function, I just wanted to use the properties of the natural exponential function.   I wanted to use a sequence that converges against $0$ and is monotone and bounded. But I'm not sure whether this might work.  The reason to consider this limit in the first place is to determine the derivative of the exponential function $x \mapsto a^x$.  However, I am not currently interested in computing this limit or derivative—I just want to show that the limit exists.


How to organize this type of list in alphabetical order by the name key?

I'm using python 3 I was able to create a list with dictionaries, now I need to sort by the "name" key in alphabetical order. contact= [     {         'name': 'Jhon',         'id': 18,         'tel': "11111111111"     }, {         'name': 'Brian',         'id': 56,         'tel': "2222222222"     }, {         'name': 'Adrian',         'id': 20,         'tel': "3000000000"     } ]  The result should look like this: contact= [     {         'name': 'Adrian',         'id': 20,         'tel': "3000000000"     }, {         'name': 'Brian',         'id': 56,         'tel': "2222222222"     },{         'name': 'Jhon',         'id': 18,         'tel': "11111111111"     } ]


Conceptual questions: Variance of a process

Wikepedia, at , mentions an expression of variance for an AR(1) process. I am learning signal processing (beginner level) and facing difficulty in understanding some basic relations. It shall be really helpful if the following doubts are answered.  An AR(1) process is defined by $$X_t = c+\theta X_{t-1} + \epsilon_t$$  where $\epsilon_t$ is a zero mean white Gaussian noise.  We may compute expected values  $$E[X_t] = E[c] + \theta E[X_{t-1}]+E[\epsilon_t]$$  implying $E[X_t] = \mu = c/(1-\theta)$.  I am interested in the variance, which is defined as $$\text{Var}(X_t) = E[X_t^2] - \mu^2.$$  However, I read that $$\text{Var}(X_t) = \sigma_\epsilon^2/(1-\theta^2).$$  How is this derived?


Windows 10 fresh installation on Windows 8.0 OEM Notebook

I have a Windows 8.0 laptop (Windows was pre installed). I think there is a possibility of upgrading to Windows 10 using media creation tool or use Windows 8 key for Windows 10 fresh install. Since I do not have direct access to the key (OEM product) and don’t want lose time to upgrade to Windows 8.1 first and update it etc. my question is: will Windows 10 accept the Windows 8.0 key from the BIOS? Microsoft update policy has changed since 2015!!! Please do not associate this question with previous one.


I am getting the following error when image styles are being created on my Drupal 7.24 site:     mod_fcgid: stderr: PHP Fatal error:  Allowed memory size of 134217728   bytes exhausted (tried to allocate 73834563 bytes) in   modules/system/image.gd.inc on line 237"   My style is doing a scale and crop down to 300x200.  I know this could be a problem with my memory limit, which is currently 128M.  As this is high, this doesn't seem like an issue.   Could it be from the use of the " module for my image names?


Why is there a $2$ at the denominator of the mean squared error function?

In the famous , in chapter 1, equation 6, the Quadratic Cost (or Mean Squared Error) in a neural network is defined as  $ C(w, b) = \frac{1}{2n}\sum_{x}||y(x)-a||^2 $  where $w$ is the set of all weights and $b$ the set of all biases, $n$ is the number of training inputs, x is the set of all training inputs, y(x) is the expected output of the network for input x, and $a$ is the actual output of the network for input $x$, with respect to $w$ and $b$.  Most of this formula seems very clear to be, except the $2$ in the denominator. If I understand it correctly, we are summing up the squared vector length of (the actual output minus its expected output), for each training input (giving us the total squared error for the training set) and then divide this by the number of training samples, to get the mean squared error of all training samples. Why do we divide this by $2$ as well then?  In other places I've seen that Andrew Ng's lecture defines the Mean Square cost in a similar way, also with the $2$ in the denominator, so this seems to be a common definition.


Why can I feel the air inside the pump pressing against my finger when it is at 1 bar (atmospheric pressure)?

Atmospheric pressure is approximately 1 bar, but when I cover my bike pump with my finger and increase the pressure to 1 bar I can feel it pushing my finger away - how come?  I'm guessing that what bike pumps call 1 bar is actually 1 bar above atmospheric pressure - otherwise they it should read 1 bar to begin with, right?  I am disappointed that as a 4th year physicist I can't figure this out...


Can I splice a chandelier cord to reach a junction box?

I purchased a Arteriors' Geoffrey chandelier. Unfortunately, when I got it home I realized that the chain and wire are not long enough to hang from our 14' ceiling.  I called an electrician to install it and he told me I would have to have the fixture's wiring completely replaced before they would install. Is there a reason why I cannot purchase additional wire and chain and extend?  The printing on the wire: (UL) E309953 SPT-2 2x1.31mm (16AWG) 105oC 300V VW-1 FT2 TOONG YEAN HSF  There is also a ground wire separate from this that runs to the fixture.


There exists surjections from A onto B and vice versa, and there is no bijection between the sets?

Looking at the top answer on this page,    A user said,      There are models of ZF such that $A,B$ are sets for which exists   surjections from $A$ onto $B$ and vice versa, however there is no   bijection between the sets.   Can anyone give an example of this?  If A is the set of real numbers and B is the set of natural numbers , then there will be a surjection from A to B, but no surjection from B to A.  Is this what surjection even means.  Here is a surjection from real to naturals  1.5 → 1  1.7 → 1  2.3 → 2  2.6 → 2  f(A) = int(A) → B  But there is no surjection from the naturals to the reals (Cantor's diagonal proof)  So, how is it even possible to have "There exists surjections from $A$ onto $B$ and vice versa, and there is no bijection between the sets"? Did he, maybe, mean there is no way to find the formula for the bijection?


Meaning of different icons in the SSMS Object Explorer

I have noticed that the Database symbol to the left of the Server name in the object explorer tends to differ without any obvious reason. Two servers have a database symbol with a Green arrow on them and another server has a database symbol with a blue question mark (?). I use windows authentication on all servers. What is interesting is that I have two virtual desktops open (all connected to the same servers, but only one VDesktop has the blue icon/symbol. the rest are Green with a white arrow on them). I just noticed this and was curious if anyone knew what they meant?   Just curious, because the Blue Question Mark is on my production server. Just want to make sure its no cause for concern. Sorry if the answer is very obvious


Why does my setup for no password prompt in /etc/sudoers not work?

My sudo version is  $ sudo --version Sudo version 1.8.16 Sudoers policy plugin version 1.8.16 Sudoers file grammar version 45 Sudoers I/O plugin version 1.8.16  $ which sudo /usr/bin/sudo  $ whereis sudo sudo: /usr/bin/sudo /usr/lib/sudo /usr/share/man/man8/sudo.8.gz   :  # User privilege specification root    ALL=(ALL:ALL) ALL # my change for scaling down cpu freq t       ALL=(ALL) NOPASSWD: /home/t/program_files/hardware/cpu/cpuFreq/changeCpuFreq.sh   But after I reboot Ubuntu 16.04, I still need to provide password when running the script with sudo:  $ sudo /home/t/program_files/hardware/cpu/cpuFreq/changeCpuFreq.sh  1600000 [sudo] password for t:    I was wondering why?  Note that in /etc/sudoers,    I notice that the separator between root and ALL is a tab, and I also separate t and ALL with a tab, and the other separators are spaces. Originally I separated t and ALL with a few spaces, which didn't work. Does what the separator is matter? /home/t/program_files/hardware/cpu/cpuFreq/changeCpuFreq.sh is pathname without any symlink, and originally, I tried a symlink, which didn't work. Does a symlink matter or not?   Thanks.    Update:  As the reply by steve suggested, I changed the line in /etc/sudoers to be  t       ALL=(ALL) NOPASSWD: /home/t/program_files/hardware/cpu/cpuFreq/changeCpuFreq.sh *   by adding * at the end, but it doesn't work.  Currently my /etc/sudoers looks like  # # This file MUST be edited with the 'visudo' command as root. # # Please consider adding local content in /etc/sudoers.d/ instead of # directly modifying this file. # # See the man page for details on how to write a sudoers file. # Defaults        env_reset Defaults        mail_badpass Defaults        secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin"  # Host alias specification  # User alias specification  # Cmnd alias specification  # User privilege specification root    ALL=(ALL:ALL) ALL # my change for scaling down cpu freq # t     ALL=(ALL:ALL) NOPASSWD: /home/t/program_files/hardware/cpu/cpuFreq/changeCpuFreq.sh * t ALL=(ALL:ALL) NOPASSWD: /home/t/program_files/hardware/cpu/cpuFreq/changeCpuFreq.sh *  # Members of the admin group may gain root privileges %admin ALL=(ALL) ALL  # Allow members of group sudo to execute any command %sudo   ALL=(ALL:ALL) ALL  # See sudoers(5) for more information on "#include" directives:  #includedir /etc/sudoers.d   The groups of t include adm (is adm same as admin?) and sudo:   $ groups t t : t adm cdrom sudo dip plugdev lpadmin sambashare   The commands allowed to be run by t are:  $ sudo -l Matching Defaults entries for t on ocean:     env_reset, mail_badpass,     secure_path=/usr/local/sbin\:/usr/local/bin\:/usr/sbin\:/usr/bin\:/sbin\:/bin\:/snap/bin  User t may run the following commands on ocean:     (ALL : ALL) NOPASSWD:         /home/t/program_files/hardware/cpu/cpuFreq/changeCpuFreq.sh *     (ALL : ALL) ALL


How can I mitigate the risk of switching to portable HDDs for long-term archiving?

I have quite a few DVDs of non-critical archived material - burned in different years, different disc manufacturers, different drives - but certainly some are now about 10 years old.   I've read this question:    about long-term archival media, and I understand there is no silver bullet, but my dilemma has some specific constraints:   I (think I) have to replace my aging DVDs with something I'm willing to spend no more than a few hundred USD, maybe even less. In fact, if I lost this entire archive, I would be annoyed and distraught, but not devastated. The archived material does not become useless if some of it is lost I want to reduce the amount of space my archive takes up; right now my DVDs are in an 'album' of sleeves.   So, I was considering switching to a portable HDD. I'm assuming that I'll replace it every 10 years or so with whatever is available then; but I still fear for the longevity of this choice. With that in mind,   How useful is it to use ZFS with Reed-Solomon codes for storage? Are there other software solutions (not RAID, since we're talking about a single drive, but perhaps RAID between areas of the drive) I could use to increase longevity? Is it a good idea to buy two different portable HDDs and occasionally overwrite one of them with the other? Is the longevity of SSDs higher than that of HDDs when writes are infrequent, as in my case? Should I maybe just get a BluRay recorder and some good-quality discs instead?   To emphasize: I need to make a decision for my own specific scenario.


How can I align 2 paths perfectly? No matter what I do I get a little space (gap between the 2 paths I create, and they are straight lines not as I saw in other questions with pixel problems)  An example:    Between every triangle is a little space, like in the example. It isn't obvious and it doesn't bother, but if I use the image (as an SVG or something) it is really obvious.


Is it true that the set $P$ of all injections $\mathbb{N} \to \mathbb{N}$ is equal to the set $\mathbb{R}$

$\mathbb{R}$-real. $\mathbb{N}$-natural. Is it true that the set $P$ of all injections $\mathbb{N} \to \mathbb{N}$ is equal to the set $R$?


displaying image metadata in Tex or LaTex

Hi I've been struggling with a Floss solution to showing keywords or descriptions of an image as a caption beneath it.   My particular use case is that I have a folder of hundreds of images, I use on average 40 of these images at a time that will be laid out for printing. I don't want to manually input a description or keyword for each image as this is already part of the image metadata. Is there a way to display the image metadata in Tex or LaTex?


Users posting a series of identical comments should be brought to moderator attention

We've had a number of instances over on Stack Overflow involving users who get to the reputation level where they can comment, then spam comments across the site. Due to the lack of community review around comments, these spammed comments can remain on the site for months before someone notices and flags one. Moderators then have to go and manually remove each of these comments. In the last few months, I've personally had to deal with two users who spammed their website across 200+ questions each.  This isn't just limited to people spamming comments with a URL in them. We've had a number of users spray the same nonsense comment or insult across tons of posts and have no one seem to notice for months.  What I'd like is some kind of system-generated notification when a user has posted a barrage of copied-and-pasted comments. This could possibly be triggered when a user has posted a set number of identical comments in a row (4 of them, maybe) or maybe even if they've posted the same comment multiple times. We receive similar system-generated flags when users post duplicate answers, edit many of their posts in a row, or delete many of their own posts at a time.  This system-generated flag should ignore comments generated by review (which have the same text in them). I'm thinking that it shouldn't ignore comments generated by custom off-topic reasons, because someone using the exact same close reason over and over again might be something we want to look into.  The flag itself won't do anything to a user, and would only appear to moderators. I imagine there will be a number of false positives, but it should be easy for us to check these and identify the well-intentioned stock comments from the problematic ones.   We currently have no means of detecting comment spam, so even if this didn't have a great hit rate it would still be beneficial on the balance. Running sample queries for this seems to indicate that it wouldn't have that much noise.  This would allow us to catch comment spam early, and prevent it from living on the site or developing into a more serious problem.


How many $3 \times 3$ integer matrices are orthogonal?

Let $S$ be the set of $3 \times 3$ matrices $\rm A$ with integer entries such that $$\rm AA^{\top} = I_3$$ What is $|S|$ (cardinality of $S$)?   The answer is supposed to be 48. Here is my proof and I wish to know if it is correct.  So, I am going to exploit the fact that the matrix A in a set will be orthognal, so if the matrix is of the form \begin{bmatrix}         a_{11} & a_{12} & a_{13} \\         a_{21} & a_{22} & a_{23} \\         a_{31} & a_{32} & a_{33} \\         \end{bmatrix}  Then each column and row will have exactly one non-zero element which will be +1 or -1. Thus, I have split possibilities for the first column into three cases and counted the possibilities in each case as follows :- $$a_{11} \neq 0$$ or $$ a_{21} \neq 0$$ or $$ a_{31} \neq 0$$  In case 1), we obviously have two possibilities(+1 or -1) so we consider the one where the entry is +1. Now, notice that the moment we choose the next non-zero entry, all the places for non-zero entries will be decided because of the rule 'each column and row will have exactly one non-zero element'. Meaning, if b and c are remaining two non-zero entries, we only have two possibilities left  \begin{bmatrix}         1 & 0 & 0 \\         0 & b & 0 \\         0 & 0 & c \\         \end{bmatrix}  or  \begin{bmatrix}         1 & 0 & 0 \\         0 & 0 & c \\         0 & b & 0 \\         \end{bmatrix}  Using the fact that b and c are simply $$\pm1$$  In each of the above matrices, we get 4 possibilities for each of the matricies. Thus, 8 possibilities in totality. Basically, we are getting 8 possibilities on the assumption that  $$a_{11} = 1$$  Thus, we get 16 possibilities on the case that $$a_{11} \neq 0$$  Following, the second and third cases analogously, we get a total of 16 possibilities in each of them and 48 possibilities in total.    Source :- Tata Institute of Fundamental Research Graduate School Admissions 2016


Why should the energy (of an eigenstate) be greater than the lowest point of the potential?

In  (on Scattering states and the step potential) by Dr. Barton Zwiebach, at $2:28$, the professor says:  "The energy of any energy eigenstate here has to be bigger than the lowest point of the potential..."  The reason provided seems a little vague - I am unable to understand how the above statement is being concluded. Could someone kindly help?


I'm trying to install ubuntu but bloody windows is making it difficult (Most of my programs stopped working after windows downloaded an update).  I tried to install ubuntu when the computer start up, even pressing f8 but it keeps going to windows.


I have a continuous response and independent variable. Can I use a neural network? to give some detail: the response variable is spray drift and the dependent variables are spray distance, wind speed and tempreture.


Named entity recognition and class imbalance

I have implemented Maximum-entropy Markov model (MEMM) for the Named entity recognition (NER) problem. I have four classes: geographical, people, material (book titles etc) and other.  Class other is overrepresented in the training & test datasets. It occurs 88% (about 40k samples) of the time.  I'm sure other authors must have had this problem. How do you suggest I go about solving this problem?  EDIT: A single data sample is a whole tagged sentence. Most of the sentence is tagged as other. I'm guessing the resampling techniques won't work here? Do you suggest I use single tokens for training dataset, instead of whole sentences?  EDIT 2: In response to my post being a duplicate: you do realize you've linked to a question that was asked 2 years after mine, right?


How to calculate remainder using Fermat's Little Theorem

I want calculate remainder when $2^{1000}$ is divided by $5^{4}$ Can I calculate it using Fermat's Little Theorem?


Nested Sequence of Topological Space and the Coherent Topology; Munkres Topology 35.9

This is problem 9 from chapter 35 in Munkres:    Here's my attempted solution:  a.   The fact that the coherent set is in fact a topology on $X$ is simple. I won't show it here.  In order to show that $X_i$ is a subspace of $X$ we must show that $\tau_i = \{X_i \cap U | U$ open in $X \}$, where $\tau_i$ is the given topology of $X_i$.  So let $U_i \in \tau_i$. Let $j < i$. Since $X_j$ is a subspace of $X_i$ (by induction), $X_j \cap U_i$ is open in $X_j$. For $i < j$ we have that, again by induction, that $X_i$ is closed in $X_j$. Since $X_i - U_i$ is closed in $X_i$ we have that $X_j \cap (X_i - U_i) = X_j - U_i$ is closed in $X_j$. So $U_i$ is open in $X_j$. It follows that $U_i = X_i \cap U_i$ where $U_i$ is open in $X$. The other direction is direct from the definition.  b.   Let $f: X \to Y$ be with $f_{|X_i}$ continuous for each $i$.  Take $x \in X$, and let $f(x) \in V$ open in $X$. $\exists x \in X_i$ for some $i$ and $f_{|X_i}(x) \in V$ as well. Since $f_{|X_i}$ is continuous $\exists x \in U_i$ open in $X_i$ s.t $f_{|X_i}(U_i) \subset V$. But $f(U_i) = f_{|X_i}(U_i)$. We've showed above that $U_i$ is open in $X$, so $f$ is continuous.   c.  Let  $A,B$ be closed and disjoint in $X$. Define $f_0: A \cup B \to [0,1]$ by $f(A) = \{0\}$, $f(B) = \{1\}$ which is continuous. We note that $A \cup B$ is closed in $A \cup B \cup X_1$ because $(A \cup B \cup X_1) \cap (A \cup B) = A \cup B$ and $A \cup B$ is closed in $X$.  By Tietze extend $f_0$ to $f_1:A \cup B \cup X_1 \to [0,1] $. Do so inductively (the above argument works for any $i$), to get $f_i$ a continuous extension of $f_{i-1}$. Define $f: X \to [0,1]$ by $f(x) = f_i(x)$ whence $x \in X_i$, it is well defined since the sequence is of extensions and the spaces are nested. By clause b. $f$ is continuous. We see that $A \subset f^{-1}([0,\frac{1}{2}))$ and that $B \subset f^{-1}((\frac{1}{2}, 1])$, disjoint open neighbourhoods of $X$.


I've tried to use \protect to make the following \edef work but no luck. Can it be done somehow?  \documentclass{article}  \usepackage{xstring}  \begin{document}  \def\abc{a,b,c} \edef\result{\StrSubstitute[2]{\abc}{,}{ }}  \result  \end{document}   NOTE: I know I can do the same using etoolbox or xpatch (and I already did that), but became curious about the problem above.


How was Dumbledore able to defeat Grindelwald, since Grindelwald had the Elder Wand?

This question:  just speculates on the transfer of ownership of the Elder Wand. But the Elder Wand is supposed to greatly enhance the powers of the wielder. Grindelwald knew he wasn't a match for Dumbledore on even terms:     Over the years, Grindelwald raised an army and began a reign of terror that spread through several European countries and murdered many wizards and Muggles, though he never attempted to take power in Britain for his fear of his former friend, Dumbledore, who was "a shade more skillful" than he was.    But the possession of the Elder Wand should have given him the edge to be able to defeat him. The Elder Wand is supposed to make a wizard nearly invincible, their spells should always be more powerful than the opposing wizard.   How was Dumbledore able to defeat Grindelwald when he was facing the most powerful wand ever made?


Is this application creating stored procedures on the fly?

We are running a transaction program that uses MS SQL Server. Lately as our number of users and locations have grown, speed/response seems to be an issue.  When looking at *sys.dm_exec_sql_text*, I see a lot of queries starting with "CREATE PROCEDURE", of which some are over 1000 lines of code. Is the application creating stored procedures on the fly or is it merely executing these stored procedures? I thought executing a stored procedure is started using "EXEC"?  If the application is constantly (re)creating the procedures, is it likely that this causes performance issues?