Using TeXworks, I can put the following code at the very top of a TeX document:  % !TeX program = LuaLaTeX % !TEX encoding = UTF-8   When TeXworks sees that, it will automatically use LuaLaTeX as compiler, and utf-8 encoding for this document, even if the program preferences are set to something else.  Alternatively, I can use various commands such as  \ifluatex{no problem}{stop, and inform the user}   My question: For the various TeX-specific editors (not general text editors), would the processing instructions for TeXworks also do the same thing? Or, is there some general way of ensuring the correct processing from the very start, without having to detect and generate an error later?

Occasionally, I see other people's documents starting with two lines like that:  % !TEX TS-program = xelatex % !TEX encoding = UTF-8 Unicode   It's clear to me that the first line declares the engine that should be used for compilation, and the second lines states the text encoding of the input file. It's not clear to me, however, when and why I should use such expressions.  More detailed questions on this subject matter would be:   How can I compile without determining which engine I want to use so that I would even need that comment? Which editors/programs pick up on these directives? Who introduced them? Is there any "documentation" of possible values etc.? Are there more such expressions? Are they standardized in any way? Can I add options to the compilation engine, e.g. pdflatex -enable-write18 or xelatex -interaction=nonstopmode? What does the "TS" in TS-program stand for? What additional value does the encoding line provide if I'm already using inputenc? Are there any downsides to using them or reasons not to use them?   Meta: Even though it technically contains multiple questions, I'm pretty sure this question conforms with our standards as a catch-all question on a narrow topic. I guess I know some partial answers to some of my questions, but I'll leave that up for people who have experience with these expressions. I just wanted to provide a question that allows for a maximal amount of information on this subject matter.


With my oneliners I often want to fetch a whole file inside a string. With only core modules the only solutions I know considering $file = 'foo' are:  $str = do {local $/; open $fh, '<', $file; <$fh>};   Or   $str = qx{cat $file};   The second method is shorter to write, easier to understand, but involves a lot more complexity behind the curtain (sys_execve).   Is there any better way or a nice sugar that I don't know?

Yes,  but there must be a canonical or most efficient or most concise way. I'll add answers I know of and see what percolates to the top.  To be clear, the question is how best to read the contents of a file into a string. One solution per answer.


In Harry potter series we saw that Albus Dumbledore died at 116 years, nicolas flamel is more than 600 years old.  So what is the average age for a wizards?

In the Harry Potter series is it clear that magically-inclined individuals (witches/wizards) will live to be considerably older than their Muggle counterparts? From the question , it is given that Dumbledore was roughly 115 years old when he died, and at that age he hardly seemed ready to kick the bucket naturally.  With that in mind, how old will a wizard typically live to be, barring accidents or murder?


I try to replace "_" to "/"  $ echo "hahahaa_the_cat_hahahaa" | sed "s/_///g"   It doesn't work.

I would like to replace $fileWithPath in $file, however this doesn't work because (I think) path is not escaped. How to escape it?  sed -i 's/${fileWithPath}/HAHA/g' $file


I know the cursor can be altered to indicate a page loading:  $('body').css( 'cursor', 'progress' )   for instance... But I'm looking for a way to put the page itself in a loading stage, like the browser is doing when a page is loading, on the spot where normally the favicon would be displayed. Is there a way to change the status of that to waiting?

I have a web application that's branded according to the user that's currently logged in. I'd like to change the favicon of the page to be the logo of the private label, but I'm unable to find any code or any examples of how to do this. Has anybody successfully done this before?  I'm picturing having a dozen icons in a folder, and the reference to which favicon.ico file to use is just generated dynamically along with the HTML page. Thoughts?


I have a windows laptop .  I want to run xcode or its playground to practice on the Swift? Is there any software or solution for that?  please answer with the possible links to have?

Is there any way to tinker with the iPhone SDK on a Windows machine? Are there plans for an iPhone SDK version for Windows?  The only other way I can think of doing this is to run a Mac VM image on a VMWare server running on Windows, although I'm not too sure how legal this is.


Fund all such mappings where $A=\{1,2,3,4\}$, $B=\{1,2,3,4,5,6\}$ and $f:A \to B$ is an injective mapping such that $f(i) \neq i ~\forall i=1,2,3,4$.   I'm thinking about using the principle of inclusion and exclusion but I'm somewhat not sure how to do that. I think I'm getting lots of cases. Basically, I'm considering all possible values $i$ (for $1\leq i \leq 4$) can map to and that's basically $5$ for each $i$ since $f(i)\neq i$. After that, we will use PIE to rule out the cases when the condition $f(1)\neq f(2)\neq f(3)\neq f(4)$ isn't satisfied. But I think that's a bit of a big thing. Please continue from here; I'm not exactly getting to the destination.  Also, if some nice bijection exists, it would be quite appreciated.

How many injective functions  $f:[1,...,m]\to{[1,...,n]}$ has no fixed point? $(m\le n)$  I thought about the next thing:  $f(x_1)\neq x_1$, Means i can choose for $x_1$ - (n-1) options,  But then, for $x_2$, there are two options:   If i choose $f(x_1)=x_2$ then for $x_2$ i still have (n-1) options. If i choose $f(x_1)\ne x_2$ then for $x_2$ i'll have (n-2) options.   So how can i take care of that? Or am i looking the question totally wrong?


I have OpenStreetMap data, which represents larger roads (e.g. dual carriageways, aka divided highways) as parallel lines.  The question is answered for ArcGIS or Skeletron , for example using ESRI's  or Collapse Dual Lines to Centerline tools.  Does anyone have suggestions for how to do this within PostGIS? I am working on a server without ArcGIS, and would like to avoid the overhead of transferring the data back and forth across machines.  Update The linked question isn't really answered, and is looking for a solution that is not PostGIS. This should be kept open.

Streets in Openstreetmap have more detail than I need. For instance I do not need seperate street tracks for each driving direction, instead I just want to show the general path of the street. Example:    OSM linestrings for a street    Simpified linestring(s) (here it is just one, but in case of sidearms would be > 1)  input:  collection of linestrings output: collection of linestrings  simplified lines = f(osm lines) f = ?   the output is a collection as well, since sidearms should remain available.  How do I programatically simplify such linestring collections?  Would like to use JTS, NTS, GEOS but not PostGIS if possible.


I modelled something and want to select some specific faces for this object to give it another material. Works with applying. But now I have an existing material and don't know how to change it (e.g. make it darker) without changing it for all the other faces too.  When I click on the second material slot and want to change it and apply, the first slot changes too. How do I avoid that?

I want to create a new material based on an existing material. For that a need a copy of the existing material as a starting point. How can I make such a copy?


We have $n,n+1, n+2 \in \mathbb Z^+$  Their product can't be a whole exponentiation. Why?    I noticed that $gcd(n,n+1)=1$ and $gcd(n+1,n+2)=1$ This could be a good starting point in the proof. But how do I proceed? Thanks

I am trying to prove that the product of three consecutive positive integers is never a perfect power. Can anyone point to gaps in my proof and/or post an alternate solution?  Let the three positive consecutive integers be $n - 1$, $n$ and $n + 1$ and let $(n - 1)n(n + 1) = h^k, k \ge 2$. Note that $\gcd(n - 1, n) = 1$ and $(n, n + 1) = 1$ implies that $n$ itself must be a perfect power and of the form $z^k$ (which is apparent once we look at the canonical representation of $h^k$). That means $n^2 - 1$ must be a perfect power itself and of the form $a^k$. If $n$ is odd, $n = 2m + 1$ for some $m \in \mathbb{N}$ i. e. $(n - 1)(n + 1) = 2m(2m + 2) = 2^2m(m + 1) = a^k$. Using the fact that $(m, m + 1) = 1$, $m$ and $m + 1$ must be perfect powers themselves and so $k\leq 2$. Coupled with fact that $k > 1$, we infer $k = 2$. So, $n^2 - 1 = a^2$ which implies $n$ is not a natural number. We are left with the case when $n$ is even. Let $n = 2t + 1$. $(n + 1, n - 1) = 1$ as both are of (by the Euclidean algorithm). That means $n - 1$ and $n + 1$ are perfect powers. So, let $(n - 1) = b^k$ and $(n + 1) = l^k$. So, $l^k - b^k = 2$ for natural $l$ and $p$ and $k>1$. I will prove that the diophantine equation has no solutions. Consider the function $f(k) = l^k - b^k - 2$. $f'(k) = \frac{1}{l}e^{k\log l} - \frac{1}{b}e^{k\log b}>0$ if and only if $e^{k(log\frac{l}{b})}>\frac{l}{b}$. Taking logarithm again, we get an equivalent condition $(k - 1)\log\frac{l}{b}>0$ which is true as $k>1$ and $l>b$ as log is a monotonically increasing function.  Is my proof correct? Please feel free to chip in with your own solutions!


MWE:  \documentclass[12pt]{article}  \usepackage{tikz} \usetikzlibrary{arrows.meta, graphs, matrix, quotes}  \usepackage{fancyhdr} \pagestyle{empty}  \begin{document}   \begin{tikzpicture}     \matrix[matrix of nodes, column sep= 2em] {       |(n1)| node 1 & |(n2)| node 2 \\       |(n3)| node 3 \\     };     \graph[use existing nodes]{       n1 -> ["label"] n2;       % n2.east -> ["label"] n3.east;       n2.east -> [to path={-- ++(1em, 0)  |- (\tikztotarget)}]  n3.east;     };   \end{tikzpicture}    \begin{tikzpicture}     \matrix[matrix of nodes, column sep= 2em] {       |(n1)| node 1 & |(n2)| node 2 \\       |(n3)| node 3 \\     };     \graph[use existing nodes]{       n1 -> ["label"] n2;       n2.east -> ["label"] n3.east;       % n2.east -> [to path={-- ++(1em, 0)  |- (\tikztotarget)}]        % n3.east;     };   \end{tikzpicture} \end{document}     In the first example, I have shaped the edge. In the second one, I have labeled, but not shaped, that edge. I tried using to path and the quotes syntax together, but:   If I do it in that order, it has no effect (only shaped edge) If I reverse the order of the options, the label appears, but the edge is straight   How can I do both things at the same time?

I can put labels onto normal edges fine, but when the edge has a style applied to it, the label is no longer applied.  Any idea what is going on/how to fix this?   \documentclass{standalone} \usepackage{tikz} \usetikzlibrary{graphs,quotes} \begin{document} \tikz[hv path/.style = {to path={-| (\tikztotarget)}}] \graph[grow down sep, branch right = 4em] { A ->["this prints"] B ->{C,D}; A ->[hv path,"this doesn't"] D; };  \end{document}


I just would like to know if there is a way to check if a div with the overflow hidden attribute can be checked to see if it has content overflowing it or not. Jquery

Can I use JavaScript to check (irrespective of scrollbars) if an HTML element has overflowed its content? For example, a long div with small, fixed size, the overflow property set to visible, and no scrollbars on the element.


This is my code:  var data = {}; data.uuid = uuid; data.method = "addAddress";  //Other parameters var par = {}; par.name = "test"; par.surname = "test";  data.concat(par); //doesn't work  var url = myURL; var result = $.ajax({     url: url,     data: data,     async: false });   I want to merge two variables array. It is possible to merge this variables?

I need to be able to merge two (very simple) JavaScript objects at runtime.  For example I'd like to:  var obj1 = { food: 'pizza', car: 'ford' } var obj2 = { animal: 'dog' }  obj1.merge(obj2);  //obj1 now has three properties: food, car, and animal   Does anyone have a script for this or know of a built in way to do this?  I do not need recursion, and I do not need to merge functions, just methods on flat objects.


So I put some pulled pork in the crock pot on low for about 5 hours when my boyfriend turned it off without me knowing.. Recipie said 7 hours total on low. So after about 3 hours of it being off we turned it on warm and left it on overnight.. In the morning I turned it back up to low and it cooked for about another 5 hours (I was told you can't really overcook pulled pork, just gets more tender) and I am wondering if it is safe to eat??

If I leave fully-cooked food (particularly meat) out at warm temperature - say on the counter or in a crock pot that's been turned off -  how long will it stay safe to eat?  Does it make any difference if I re-cook the food afterward?


I have a Component that I attach to projectiles spawned by my character. I would like to make a callback function that is called when the projectile hits a valid target. In Component.h I declare a function :     template<class T>     void OnTargetHit( void (T::*Callback)() );  In Component.cpp is implementation: template<class T> void UInterpolationComponent::OnTargetHit( void (T::*Callback)() ) {     (T::*Callback)(); }  Now in my Character.cpp I would like to Get the component and assign it a "callback" function, a function that would be triggered when te target is hit, ofcourse this component could be applied to different Actors, therefore I want to pass a function from the calling class so I provide a specific implementation:     AActor* Projectile = GetWorld()->SpawnActor<AActor>(PrimaryAttackProjectile_BP, GetActorLocation(), Rotation);      UInterpolationComponent* InterpComp = Cast<UInterpolationComponent>(Projectile->GetComponentByClass(UInterpolationComponent::StaticClass()));     InterpComp->InterpSpeed = 1800.f;     InterpComp->bHoming = false;     InterpComp->StaticTarget = Location;     InterpComp->bIsDestroyable = true;     InterpComp->OnTargetHit<ACartagraCharacter>(&CalculateDamage);  The problem is with the last line of code :     InterpComp->OnTargetHit<ACartagraCharacter>(&CalculateDamage);  I'm not sure if I should pass an ampersand or not, If I should Include the class name, I tried all of the following:     InterpComp->OnTargetHit<ACartagraCharacter>(CalculateDamage);     InterpComp->OnTargetHit<ACartagraCharacter>(&ACartagraCharacter::CalculateDamage);  None of them work, either gives me an ampersand error, or if in the last case presented it gives me a linker error. I also tried making them static functions, but that doesn't make too much sense as the component is instanced on each spawned projectile. I'm new to template functions and not sure how I'm supposed to do this. Please help.

Quote from :     The only portable way of using templates at the moment is to implement them in header files by using inline functions.   Why is this?  (Clarification: header files are not the only portable solution. But they are the most convenient portable solution.)


I am trying to modify this report that I have. The report is supposed to identify changes to attributes of a set of data.  For example, a person and his address with respect to his lease renewals. So imagine that the person was at address-1 from 1-1-2018 through 3/12/2018, then moved to another address-2, initially signing lease for 3/12/2018 through 12/31/2021, but then changed the lease later to 3/12/2018 through 10/1/2018. He then went ahead and extended his lease from 10/2/2018 to 12/31/2020. In this case, i want to not show the initial lease signing period of 3/12/2018 through 12/31/2021. The current table stores all of these records and i don't want this particular row to be shown just so the end user doesn't get confused.   The way I look at it, if i am able to get all the "duplicates" in columns Person, Person_ID, Phone_Number, end_date and then for those duplicate rows only keep the highest start_date, i would be able to be report out the right way. I am, however, stuck in my ability to eliminate the min(start_date) from those rows while showing all of the data.   select      subset.person,      subset.person_id,      subset.phone_number,      subset.end_date,      count(*) from subset group by      subset.subset.person,      subset.person_id,      subset.phone_number,      subset.end_date having count(*)>1 order by person_id;   Now for these rows, i need to select the max(start_date) and keep only those in the report (I think i am stuck there).   So the table essentially shows the following:  Person  Person ID   Phone Number    Address 1   Zip Code    Start Date  End Date Jane    1   8792029484  some address-1  12345   3/5/2016    11/9/2018 Jane    1   8792029484  some address-2  34455   11/10/2018  12/31/9999 Jane    1   8792029484  some address-2  34455   11/10/2018  12/7/2018 Jane    1   8792029484  some address-2  34455   12/8/2018   12/31/9999 John    2   9808845768  another address-1   68687   1/1/2013    11/9/2018 John    2   9808845768  another address-2   89384   11/10/2018  12/31/9999 John    2   9808845768  another address-2   89384   11/10/2018  12/7/2018 John    2   9808845768  another address-2   89384   12/8/2018   12/31/9999   For Jane and John, I don't want the following rows to be displayed:      Jane    1   8792029484  some address-2  34455   11/10/2018  12/31/9999     John    2   9808845768  another address-2   89384   11/10/2018  12/31/9999   Expected result:     Person   Person ID   Phone Number    Address 1   Zip Code    Start Date  End Date    Jane 1   8792029484  some address-1  12345   3/5/2016    11/9/2018    Jane 1   8792029484  some address-2  34455   11/10/2018  12/7/2018    Jane 1   8792029484  some address-2  34455   12/8/2018   12/31/9999    John 2   9808845768  another address-1   68687   1/1/2013    11/9/2018    John 2   9808845768  another address-2   89384   11/10/2018  12/7/2018    John 2   9808845768  another address-2   89384   12/8/2018   12/31/9999

Table:   UserId, Value, Date.   I want to get the UserId, Value for the max(Date) for each UserId. That is, the Value for each UserId that has the latest date. Is there a way to do this simply in SQL? (Preferably Oracle)  Update: Apologies for any ambiguity: I need to get ALL the UserIds. But for each UserId, only that row where that user has the latest date.


I have two .csv files namely file1.csv and file2.csv  file1.csv  ADIS BAP3 Mercury_System nxh-2003 DR_FeatureUP_PT   file2.csv  ADIS,projects.adis EcoSystems,projects.ecosystems em1xxxsw,projects.em1xxxsw BAP3,projects.bap3 Dirana4,projects.dirana4 Mercury_System,projects.mercury_system nxh-2003,projects.nxh-2003 DocStore,projects.docstore DR_FeatureUP_PT,projects.dr_featureup_pt   Desired output.csv  ADIS,projects.adis BAP3,projects.bap3 Mercury_System,projects.mercury_system nxh-2003,projects.nxh-2003 DR_FeatureUP_PT,projects.dr_featureup_pt   I have already tried couple of codes below, but none of them worked for me as per the requirement  grep -Ff file1.csv file2.csv > outfile.csv  awk -F, 'NR==FNR{seen[$0]++;next} ($1 in seen)' file1.csv file2.csv > outfile.csv   file1.csv contains 2500 rows and file2.csv contains 118 rows, so it should compare and give me only results which are matching to file2, output should be matching to 118 rows/results.

I am using Solaris 10 and so grep options involving -f don't work.  I have two pipe-separated files:   file1:  abc|123|BNY|apple| cab|234|cyx|orange| def|kumar|pki|bird|   file 2:   abc|123| kumar|pki| cab|234   I would like to compare the first two columns of file2 with file1 (search through the entire contents of file1 in first two columns) if they match print the matched line of file1. Then search for the second line of file 2 and so on.   Expected Output:  abc|123|BNY|apple| cab|234|cyx|orange|   The files I have are huge, containing about 400,000 lines, so I would like to make the execution fast.


Let $l_p=\{(x_n)\in\mathbb{R}^\mathbb{N}: \sum_{n=0}^\infty |x_n|^p<\infty\}$ and consider the following norm in $l_p$: $$\|x\|_p=\left(\sum_{n=0}^\infty|x_n|^p\right)^{1/p}$$ for $x=(x_n)_{n\in\mathbb{N}}$. I'm studying this norm, and I have to prove that the inequality $\|x+y\|_p<\|x\|_p+\|y\|_p$ holds for $x\neq \lambda y$, $\lambda>0$.   My attempt: the restriction is needed because if $y=\lambda x$ then the equality $$\|x+y\|_p=\|(1+\lambda)x\|_p=|\|x\|_p+\lambda\|x\|_p=\|x\|_p+\|y\|_p$$ holds ever.   Now I do the particular case $y=-\lambda x$, for $0<\lambda\leq 1$ (and $x\neq 0$) then:  $$\|x+y\|_p=\|x-\lambda x\|_p= \|(1-\lambda)x\|_p=(1-\lambda)\|x\|_p=\|x\|_p-\lambda\|x\|_p<\|x\|_p+\|y\|_p$$  (the ''$<$'' is because $\|x\|_p>0 $)  Now if $\lambda>1$, I found that the inequality holds again with '''<'' just following a similar approach.     But how can I proceed in the general case? Thanks in advance!

I'm following the book Measure and Integral of Richard L. Wheeden and Antoni Zygmund. This is problem 4 of chapter 8. Consider $E\subseteq \mathbb{R}^n$ a measurable set. In the following all the integrals are taken over $E$, $1/p + 1/q=1$, with $1\lt p\lt \infty$. I'm trying to prove that $$\int \vert fg\vert =\Vert f \Vert_p\Vert g \Vert_q$$ if and only if $\vert f \vert^p$ is multiple of $\vert g \vert^q$ almost everywhere. To do this, I want to consider the following cases: if $\Vert f \Vert_p=0$ or $\Vert g \Vert_q=0$, we are done. Then suppose that $\Vert f \Vert_p\ne 0$ and $\Vert g \Vert_q\ne 0$. If $\Vert f \Vert_p=\infty$ or $\Vert g \Vert_q=\infty$, we are done (I hope). If $0\lt\Vert f \Vert_p\lt\infty$ and $0\lt\Vert g \Vert_q\lt\infty$, proceed as follows. When we are proving the Hölder's inequality, we use that for $a,b\geq 0$ $$ab\leq \frac{a^p}{p}+\frac{b^q}{q},$$ where the equality holds if and only if $b=a^{p/q}$. Explicitly $$\int\vert fg \vert\leq \Vert f \Vert_p \Vert g \Vert_q \int\left( \frac{\vert f \vert^p}{p\Vert f \Vert_p^p} + \frac{\vert g \vert^q}{q\Vert g \Vert_q^q}\right)=\Vert f \Vert_p \Vert g \Vert_q.$$ From here, we see that the equality in Hölder's inequalty holds iff $$\frac{\vert fg \vert}{\Vert f \Vert_p \Vert g \Vert_q}=\frac{\vert f \vert^p}{p\Vert f \Vert_p^p} + \frac{\vert g \vert^q}{q\Vert g \Vert_q^q}, \text{ a.e.}$$ iff $$\frac{\vert g \vert}{\Vert g \Vert_q}=\left( \frac{\vert f \vert}{\Vert f \Vert_p} \right)^{p/q},\text{ a.e.}$$ iff $$\vert g \vert^q\cdot \Vert f \Vert_p^p=\vert f \vert^p \cdot \Vert g \Vert_q^q,\text{ a.e.}$$ Q.E.D. But, assuming that $\Vert f \Vert_p\ne 0$ and $\Vert g \Vert_q\ne 0$, what about when $\Vert f \Vert_p=\infty$ or $\Vert g \Vert_q=\infty$? How can I deal with it? In the case of Minkowski inequality, suppose that the equality holds and that $g\not \equiv 0$ (and then $\left( \int \vert f+g \vert^p\right)\ne 0$). I need to prove that $\Vert f \Vert_p$ is multiple of $\Vert g \Vert_q$ almost everywhere. I can reduce to the "Hölder's equality case". I can get $$\vert f \vert^p=\left( \int \vert f+g \vert^p\right)^{-1}\Vert f \Vert_p^p\vert f+g \vert^p$$ $$\vert g \vert^p=\left( \int \vert f+g \vert^p\right)^{-1}\Vert g \Vert_p^p\vert f+g \vert^p$$ almost everywhere, but again, using the finiteness and nonzeroness of $\Vert f \Vert_p$ and $\Vert g \Vert_p$.


I am trying to center graphics in TexShop. This is the code that I am using but the graphics are not getting centering whatever I try to do.    \begin{figure}[H]     \centering     \includegraphics[height = 2.3in]{/Users/LOCATION/Matrix1.png}        \caption{Generated Matrix} \end{figure}   The code is giving me this image    I tried using   \begin{center} ... end{center}   instead of \centering but nothing seems to be fixing the problem.  EDIT 1 : Full Code  \documentclass[11pt]{article} \usepackage{graphicx} \usepackage{amsmath} \begin{document}  \begin{figure}[H]      \centering     \caption{Generated Matrix}       \includegraphics[height = 2.3in] {/Users/Max/Desktop/Math IA/PhysicsDrawings/Matrix1.png} \end{figure} \end{document}

I want to import graphics into my main input file using the macro \includegraphics. It does not work if the filename contains spaces.   also discusses this subject, but there is no solution there.  My compilation routine is latex->dvips->ps2pdf (because of PSTricks).


I have a Mac Mini with no attached camera. I would like to use the feature of Preview that allows you to insert a signature. This relies on taking an image of your signature using an isight/facetime/webcam. I do not have on.  I do have a MacBook pro on which I use the signature function. Is there a way to copy a file from the the MacBook Pro to the Mac Mini to enable this function on the Mini?

A follow on to . Is it possible to just copy the plist file containing the signature from one Mac to another? Is there a recommended method for exporting and import signatures from one Mac to another I should follow instead?  I could "sign" a blank PDF and take a screen shot of it but but I really want the same password to go along with the image so it's 100% the same signature on the other Mac as the one I'm using on this Mac.


In ArcGis, we can check x y size of each pixel in raster property. How to check in Qgis?

How do you get the cell size of a GRASS raster in QGIS? QGIS has properties, but no raster cell size.


How do you format an external hard drive to ext4 via the command line in ubuntu?

I want to know how to format a storage drive from the terminal. Helpful things to provide in the answer would be often used options for commands and base knowledge that one can use to extrapolate future uses. Specifically I would like to know how to format in the different file systems such as NTFS, FAT32, EXT4, etc. Information on how to partition the drive via terminal is also wanted.  I am trying to format a high capacity external hard drive (EHDD) into NTFS - from the terminal.   I know I can use gparted for this as well as other GUI programs, but I still want to now how to do it from the terminal.


I have imported assets in blender and saved it. After I have added some assets and deleted the old ones. But the file size keeps on increasing.

I made a huge project, wanted to reduce file size from 1.3GB to below 1GB. Compressing did not help. I removed objects from scene. Also textures. I then realized, the file size even was the same when I delete ALL objects. Why?  Download of sample:   Before deleting all: 1.2GB, after: 1.1GB.


I have an attribute table with a real data type column named "Volume". Some of these cells have no value, and I want to replace the NULL with a dummy value like -999.  In the Field Calculaor I select "Update Existing Field", select the "Volume" field and I attempt the following:  1) I code CASE WHEN NULL THEN -999 END - Result: the entire column becomes NULL.   2) Then I try CASE WHEN  "Volume" IS NULL THEN -999 END - Result, the NULL valued cells now show -999 BUT all the other formerly filled cells are now NULL. After many hours of trying other expression variations I can't figure this out. My guess is I am missing a basic concept.  Oh, and how can I "undo" a bad field calculator update besides quitting QGIS and  discarding the updates.

I'm trying to replace selected string values in an attribute table, eg. "Text1" for "Text2" (QGIS 1.8.0), patriculary for those rows with NULL values. I have been trying to use the replace expression (and any other that I have found) with no luck.  Are there any wildcard characters that I may be able to use in future?


when I ever I want to make most of the things in terminal I faced this problem ,even when I try to run sudo apt upgrade , it also appear I try to reinstall it by using sudo apt install --reinstall linux-headers-5.4.0-56 linux-headers-5.4.0-56-generic and it appear also

sudo apt update && sudp apt upgrade -y now shows the error message E:The package linux-modules-5.4.0-56-generic needs to be reinstalled. But I can't find an archive for it.  and nothing proceeds. How can I fix this problem? Thanks.


Our server was compromised last week.  The developer team I was working on hadn't been backing up our work or using GIT Hub, so everything that we've been working on is on the server.  I know that we need to rebuild the server.  I was wondering if there is anyway to salvage the project, or if we should delete our changes and start over.

This is a  about Server Security - Responding to Breach Events (Hacking)   See Also:                  Canonical Version I suspect that one or more of my servers is compromised by a hacker, virus, or other mechanism:   What are my first steps? When I arrive on site should I disconnect the server, preserve "evidence", are there other initial considerations? How do I go about getting services back online? How do I prevent the same thing from happening immediately again? Are there best practices or methodologies for learning from this incident? If I wanted to put a Incident Response Plan together, where would I start? Should this be part of my Disaster Recovery or Business Continuity Planning?   Original Version       2011.01.02 - I'm on my way into work at 9.30 p.m. on a Sunday because our server has been compromised somehow and was resulting in a    attack on our provider. The servers access to the Internet   has been shut down which means over 5-600 of our clients sites are now   down. Now this could be an FTP hack, or some weakness in code   somewhere. I'm not sure till I get there.      How can I track this down quickly? We're in for a whole lot of   litigation if I don't get the server back up ASAP. Any help is   appreciated. We are running Open SUSE 11.0.            2011.01.03 - Thanks to everyone for your help. Luckily I WASN'T the only person responsible for this server, just the nearest. We managed   to resolve this problem, although it may not apply to many others in a   different situation. I'll detail what we did.      We unplugged the server from the net. It was performing (attempting to   perform) a Denial Of Service attack on another server in Indonesia,   and the guilty party was also based there.      We firstly tried to identify where on the server this was coming from,   considering we have over 500 sites on the server, we expected to be   moonlighting for some time. However, with SSH access still, we ran a   command to find all files edited or created in the time the attacks   started. Luckily, the offending file was created over the winter   holidays which meant that not many other files were created on the   server at that time.      We were then able to identify the offending file which was inside the   uploaded images folder within a  website.      After a short cigarette break we concluded that, due to the files   location, it must have been uploaded via a file upload facility that   was inadequetly secured. After some googling, we found that there was   a security vulnerability that allowed files to be uploaded, within the   ZenCart admin panel, for a picture for a record company. (The section   that it never really even used), posting this form just uploaded any   file, it did not check the extension of the file, and didn't even   check to see if the user was logged in.      This meant that any files could be uploaded, including a PHP file for   the attack. We secured the vulnerability with ZenCart on the infected   site, and removed the offending files.      The job was done, and I was home for 2 a.m.            The Moral   - Always apply security patches for ZenCart, or any other CMS system for that matter. As when security updates are released, the whole   world is made aware of the vulnerability.   - Always do backups, and backup your backups.   - Employ or arrange for someone that will be there in times like these. To prevent anyone from relying on a panicy post on Server   Fault.


Let $A=$ $\{$ $\sum_n a_n3^{-n}$ : $a_n$ $=$ $0,2$ $\}$.  Show that $A$ as a subset of $[0,1]$ is closed:  My idea consists of taking a point $x$ in the complement of $A$.  However, I'm not sure then how to proceed. Can every element of [0,1] be expressed as a sum of $b_n3^{-n}$?  Where  $b_n=1?$  would the complement of A be of that form? May I have hints?  Please use this definition of A rather than any alternative definition.

I have encountered the definition of Cantor set and its property. Cantor set is constructed by removing the middle third open set of each interval .So each time we get some union of closed sets. As $F_0=[0,1]$ $F_1=[0,1/3]\cup [2/3,1]$ $F_2=[0,1/9]\cup [2/9,1/3]\cup [2/3,7/9]\cup [8/9,1]$ So on , That for $F_n$ we get the Union of $2^n$ closed interval . I know that finite union of closed interval is closed, but this is not true for arbitarly union. As I had a counterexample:  $\cup$ {{1/n}|for $n$ $\in N$} as this is not closed as $0$ is not in  that union. So what is the argument here to say that $F_n$ is closed for any $ n$ . As we are using this fact to prove the Cantor set to be closed as $F=\cap_{n\to \infty} F_n$ i.e arbitarly intersection of closed set is closed . Where am I misunderstanding? Any help will be appreciated.


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

How can you enumerate an enum in C#?  E.g. the following code does not compile:  public enum Suit {     Spades,     Hearts,     Clubs,     Diamonds }  public void EnumerateAllSuitsDemoMethod() {     foreach (Suit suit in Suit)     {         DoSomething(suit);     } }   And it gives the following compile-time error:     'Suit' is a 'type' but is used like a 'variable'   It fails on the Suit keyword, the second one.


I have a   It has 26" rims. Which of these spokes type do I need for my bike? Strongest or best match for the spokes I already have.  DT Swiss Champion Stainless PG Spokes DT Swiss Champion Stainless DB Spokes   thank you

I have lots of bikes and lots of interesting wheel sizes, I would like to know how to calculate the right spoke lengths for a wheel.  I appreciate that there are probably rather a lot of variables but this is something that has been an issue for me from time to time so being able to work out the right spoke length for an arbitrary wheel (did I mention that I have half a dozen or more different wheel sizes in the garage?) would be useful.  To be clear - I don't want a calculator, I want to know what the sums are.


Let $a>$ 0 and $k \in \mathbb N$. Evaluate  $$\lim_{n\rightarrow \infty} a^{-nk}\prod_{j=1}^k(a+\frac{j}{n})^n.$$  How is this accomplished?

Let $a > 0$ and let $k \in \mathbb{N}$. Evaluate: $$\lim_{n\to \infty}a^{-nk}\prod ^k_{j=1}\left(a+\frac{j}{n}\right)^n$$  Clueless on this problem. Seek your help.


When I type ps -ef , there are lots of special kernel thread processes showing.  I am not interested in kernel threads; I am only interested in user process/thread.  Is there a way that I can hide the kernel threads?

How can I ask ps to display only user processes and not kernel threads?  See  to see what I mean...


In simple linear regression analysis, is it possible that "two variables are correlated but regression (main effect) is not significant"?  What does the result mean?  NOTE: My question is different from  because my question is in simple linear regression analysis.

X and Y are not correlated (-.01); however, when I place X in a multiple regression predicting Y, alongside three (A, B, C) other (related) variables, X and two other variables (A, B) are significant predictors of Y. Note that the two other (A, B) variables are significantly correlated with Y outside of the regression.   How should I interpret these findings? X predicts unique variance in Y, but since these are not correlated (Pearson), it is somehow difficult to interpret.  I know of opposite cases (i.e., two variables are correlated but regression is not significant) and those are relatively simpler to understand from a theoretical and statistical perspective. Note that some of the predictors are quite correlated (e.g., .70) but not to the extent that I would expect substantial multicollinearity. Maybe I am mistaken, though.    NOTE: I asked this question previously and it was closed. The rational was that this question is redundant with the question "". Perhaps I do not understand the other question, but I believe these are entirely separate questions, both mathematically and theoretically. My question is entirely independent from if "a regression is significant". Furthermore, several predictors are significant, while the other question entails variables not being significant, so I don't see the overlap. If these questions are redundant for reasons I do not understand, please insert a comment prior to closing this question. Also, I was hoping to message the moderator who closed the other question to avoid identical questions, but I couldn't find an option to do so.


I'm trying to implement login with microsoft in my react native application I am using the lib "react-native-msal" for it. on IOS is working correctly but on android i'm having this error:  [Error: Attempt to invoke interface method 'com.facebook.react.bridge.ReadableArray com.facebook.react.bridge.ReadableMap.getArray(java.lang.String)' on a null object reference]  the error happens here: let config: MSALConfiguration = null;    if (Platform.OS === 'ios') {     config = {       auth: {         clientId: 'my_client_id',         authority:           'url_here',         redirectUri: 'url_here',       },     };   } else {     config = {       auth: {         clientId: 'my_client_id',         authorization_user_agent: 'DEFAULT',         authority:           'url_here',         redirectUri: 'url_here',         authorities: [           {             type: 'AAD',             audience: {               type: 'AzureADMyOrg',               tenant_id: 'ID_HERE',             },           },         ],       },     };   }  const pca = new PublicClientApplication(config, false);    try {     await pca.init();     const user = await pca.acquireToken(); // I think the error happens with this line

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


I want to decrypt a file that has been encrypted using AES-128 in CBC mode using OpenSSL. I got the “.key” file – which is 32 digits – but when I try to decrypt with OpenSSL, the program asks me for “-iv” and I don't know the IV of that file so it won't decrypt. Is there is any other way to decrypt the file without knowing the IV?   I tried with another file of which I have the correspondent IV and it works, and when I don't supply that IV, the decryption fails too.  By the way: is there anyway to know what type of encryption was used to encrypt a file?

Let's say that there is a binary file encrypted with AES in CBC mode (i.e. using a key and initialization vector). If key is known, but IV is not, is it easy to fully decrypt the file?  How hard is it?


Why is user100380 showing up in my posts instead of my full name? This is happening on all the stack exchange sites to which I am posting.

I would like to use a nickname to identify my posts, not a user + number as shown when I log in.   How do I cause the log-in process to log me in as my nickname and not the user + number id (user178183) you have assigned?  Is this perhaps 'OpenIDs are wrongly identified'?  By the way, my nicknames are intrader or mozillanerd, depending on the occassion.


This is a jfiddle    This is the result:   I want the circled div to be at the bottom of the purple div.  The circled div is this div

                          Service Level                          0%

   I tried to do this   position:relative;     bottom:0px;   but nothing changed, could u help please  (and please why my solution didn't work?)

Say I have the following CSS and HTML code:    #header {   height: 150px; }

Header title
   Header content (one or multiple lines)
     The header section is fixed height, but the header content may change.  I would like the content of the header to be vertically aligned to the bottom of the header section, so the last line of text "sticks" to the bottom of the header section.  So if there is only one line of text, it would be like:   ----------------------------- | Header title | | | | header content (resulting in one line) -----------------------------   And if there were three lines:   ----------------------------- | Header title | | header content (which is so | much stuff that it perfectly | spans over three lines) -----------------------------   How can this be done in CSS?


I am having a problem authenticating in Ubuntu 12.04. I have no password. I have bought my computer online. There is no password when I log in. It's showing me unsuccessful password. So I cannot download any app from the Ubuntu software system.

I'm working on a Ubuntu system, and my client has completely forgotten his administrative password. He doesn't even remember entering one; however it is there.  I've tried the suggestions on the website, and I have been unsuccessful in deleting the password so that I can download applets required for running some files. Is there a solution?


The nutrients from replicated food would probably be used up by the body fairly quickly, but what about materials that aren't directly consumed? Is it possible that after a period of time they would return to whatever they were before being replicated?

As  on "How did Voyager replace its photon torpedoes?"     What is special about a photon torpedo that would make them unmanufacturable without specialized tools that Voyager did not have? Everything except the payload should be doable with the push of a replicator button. And the warhead itself is just M/AM is it not?   Are there things a Replicator cannot replicate? What are the actual limits of a Replicator? Could a living being be replicated?


The Schema.org is a great tool to attract people. As I found from few sources, it doesn't provide any SEO benefits, besides the neat UI from search engines, though I wonder whether Google or any other search engine will ban website from excessive usage. For example if site has more than 10000 articles and all they marked 5 star, does this violate the usage of Schema.org and is it possible to get ban from search engines

I've inherited a site where I noticed that    there is an excessive use of Schema.org in all navigation elements pages describing products are marked as itemtype="http://schema.org/CreativeWork"   So I'm wondering if these tags are sending the wrong message and not truly optimized. I realize that the nav (1) is done in some themes, but I'm more worried about (2). Can it be a hit SEO-wise to mislabel pages instead of products?


Photon pair production in electron-positron annihilation is necessary to conserve the linear momentum. In such discussions the electron-positron pair collide with equal and opposite momentum, if they collide without the above condition then only a single photon can conserve the momentum (or two or more photons with different energies). Another question is why more than two photons are not produced in the symmetric collision of electron-positron.

I'm an engineer and have been reading about PET scanners and how they rely on the fact that a positron-electron annihilation will cause two photons to be emitted at 180 degrees from each other. After a bit of research I am left wondering on a couple of points.  From :     Conservation of energy and linear momentum forbid the creation of only one photon.   Is this simply because emitting one photon would produce a force in one direction without an equal and opposite force?     In the most common case, two photons are created, each with energy equal to the rest energy of the electron or positron.   Does it follow then that there is a (lesser) probability that 3 photons can be emitted at equal energy and equal angle of 120 degrees?


I am searching for a good free firewall and network monitor as the littlesnitch but I can't pay for this app. I want a firewall that will protect me but more of that to monitor any connection in or out of my mac so that to check if any malicious connections are establishing from or to my mac.  Thank you.

Little Snitch can block internet traffic of a particular app. Can I do something similar without (paying) Little Snitch, either by using free alternatives or configuring the OS X firewall directly?


I have (please don't fight the reason) the following html

  and now need to add position: fixed via jQuery $(".something").css("position", "fixed");  which leaves me with the following markup in the inspector

  And noooow I want to erase ; position: fixed from the style-attribute again. The only solution I came up with is storing the initial position-value via .data() and then on reversing setting it again. But that leaves me with the following markup..

  Unfortunately I can't have the position-property in the style-attribute afterwards. It overwrites my css coming on some class changes etc. what I want: I am now looking for a way to delete the parts of the style-attribute that jQuery has put there... something like $(".something").css("position", unset); Please NO !important suggestions for my css! I am more looking for a clean way to solve this issue in general, rather than a solution for my specific problem here

If I set a CSS value on a specific element using:  $('#element').css('background-color', '#ccc');   I want to be able to unset that element-specific value and use the cascaded value, along the lines of:  $('#element').css('background-color', null);   But that syntax doesn't seem to work – is this possible using another syntax?  Edit: The value isn't inherited from the parent element – the original values comes from an element-level selector. Sorry for any confusion!


find /path/to/wordpress -type f -exec chmod 664 {} \;    It seems that it find stuffs whose type is file and then exec chmod  What does {} and \ and ; is for?

I find myself constantly looking up the syntax of  find . -name "FILENAME"  -exec rm {} \;   mainly because I don't see how exactly the -exec part works. What is the meaning of the braces, the backslash and the semicolon? Are there other use cases for that syntax?


I have a set of external hard disks I'm using for backups, so except for the backup in the middle of the night they shouldn't show any activity. Now on one of the drives the LED has been blinking for hours, indicating some activity.    Is there a way to find which program/process is accessing the drive?  I'm using Windows 7 Home Premium.

Possible Duplicates:             Once or twice a day my computer starts writing significantly hard to the hard drive, the HD led is ON and the performance hit is noticeable. A strange observation is that the Task Viewer does not show I/O activity - even Process Explorer shows no CPU activity and no I/O bytes read or written.  Is there a way to know which application is using the hard drive and how much data is it reading or writing?


I asked a questing a few weeks ago, and asked a follow up question as a answer to that post? Apparently that's not allowed, so I am making this post instead.  The question is based on this thread:   Question:  The op amp that I chose has sufficient properties. However, I can't get my schematic to work. See the picture below for my schematic.  The output I am getting is my Vcc+, which is odd. I am not getting the pulses that I was looking for. I think I did something wrong, does anybody have any ideas?    Thanks!

I have built a scintillation detector. The detector outputs 0,1 ms 50-200 mV negative pulses from a photomultiplier (DC). The pulse shape is shown in the picture below.     To detect the pulses I need to change their properties (still DC however). Their new shape has to be pretty much identical, but more than 500 mV positive voltage (their duration can be 0,1 ms to 0,5 ms, but preferably 0,3 ms to 0,4 ms). The shape is, again, illustrated in the picture above.  Does anyone with more experience than me have a small form-factor schematic that will work? If I need to, I have a 5 V rail that I can power something with.   Thanks!    Update: The op amp that I chose () has sufficient properties. However, I can't get my schematic to work. See the picture for my schematic.   The output I am getting is my Vcc+, which is odd. I am not getting the pulses that I was looking for. I think I did something wrong, does anybody have any ideas?    Thanks!


Let $\alpha$ and $\beta$ be linear operators on a vector space V. Suppose that $\alpha$ satisfies a non-zero polynomial. Prove that when V is $\alpha$- cyclic, we have $\alpha \circ \beta = \beta\circ\alpha,$ then $\beta = p(\alpha)$ for some polynomial p.  My approach was to let the $p'$ be the minimal polynomial that satisfies alpha. Then let $p'(\alpha\circ\beta) = p'(\beta\circ\alpha)$ but I can't seem to proceed from here.  I think the next step I want to show is that there is a polynomial that satisfies $\beta$, but after that I am just stuck

Let $T$ be a linear operator on the finite dimensional vector space $V$. Suppose $T$ has a cyclic vector. Prove that if $U$ is any linear operator which commutes with $T$, then $U$ is a polynomial in $T$.


I always wondered how freelancers and businesses add their events to Google and Bing to make them searchable like this:    Finally I found some forum explaining that Google read them from JSON-LD format which you should embed into a web page on your web site.   I followed instructions and made one for my site in the beginning of the week for the upcoming weekend. However 5 days since it still not shown up if you type "events in walnut creek ca this weekend".  Here is .  I've also added JSON-LD for the business itself on a home page.  Any ideas what did I do wrong?

Google confirms our site has thousands of valid MusicEvent structured data objects presented using JSON-LD, as indicated in the Structured Data section of Webmaster Tools. However, rich snippets for the events do not show up in any search result pages. The Rich Cards tab in Webmaster Tools says:     We did not find any structured data for rich cards on your website.   The structured data is valid with no errors in the Structured Data Testing Tool. We do generate some warnings occasionally for missing endDate and price fields. Comparing our code to a survey of other sites whose rich snippets do appear, we are not doing anything unique in terms of our markup.  The data has been there for months, in fact over the months we've tried also using Microdata format. The Structured Data section indicates that many pages were crawled this week.  Besides SDTT validation, what else can I check to troubleshoot this issue?


Recently I passed 200 reputation and got the 100 point Association Bonus.  For the week, it says I only earned 105 reputation, then it says under my profile that I earned 210. Does the association not help? Do I quality for the Mortarboard badge?

Formerly List of all badges with full descriptions.  What are badge name's requirements? Why didn't I get badge name ? Which badges can I earn multiple times?    Jump to:                    Note: Some badges are awarded based on score. The term score means the total number of upvotes minus the total number of downvotes.  Any badge with a *** next to it is one of 20 badges that count towards the  displayed on a moderator candidate in an election. The candidate score is a total of 40 points: the first 20 are awarded based on the user's rep divided by 1000 and rounded down; the second 20 represents the total number of unique badges earned of the 20 that count. Note that if the same badge is earned multiple times, it will only count once towards the candidate score.  Any badge with a "(retired)" next to it is no longer awarded, but is retained by users who previously earned them. See  for more info on what it means for a badge to be retired.       Visit the  of the  on any site to see a complete list of badges that you can filter by earned, unearned, or type.


I need help for finding a context-sensitive grammar for the following language: $$ L = \left\{ ww \left| w \in \left\{a, b\right\}^* \right. \right\} $$ Would that be a correct context-sensitive grammar? S  -> ε | AUAV | BUBV   (1) U -> AUC | BUD          (2) CA -> AC                (3) CB -> BC                (4) CV -> AV                (5) DA -> AD                (6) DB -> BD                (7) DV -> BV                (8) U  -> ε                 (9) V  -> ε                 (10) A  -> a                 (11) B  -> b                 (12)

I need to find a context-sensitive grammar for the copy language $$L = \{ww \; | w \in \{0,1\}^* \}$$  This is what I got so far:  $\begin{eqnarray} S & \Rightarrow & \lambda \; | \; X \\ X & \Rightarrow & 0XA \; | \; 1XB \\ XB & \Rightarrow & CX \\ XA & \Rightarrow & DX \\ CX & \Rightarrow & X0 \\ DX & \Rightarrow & X1 \\ 0X & \Rightarrow & 0 \\ 1X & \Rightarrow & 1  \end{eqnarray}$  This works fine for 0101 but fails even for 00 or 11.  Could you please help me to find a solution?  Thanks in advance!


I know that to get a vector perpendicular to another two vectors, we need to take the cross product of that two vectors. But I don't know why it is like that. Anybody pls explain why it is so intuitively or just give me the proof or something........., Thank you!

I was wondering if anyone could give me the intuition behind the cross product of two vectors $\textbf{a}$ and $\textbf{b}$. Why does their cross product $\textbf{n} = \textbf{a} \times \textbf{b}$  give me a vector which is perpendicular to a plane?  I know I can just check this by using dot product but I'm not totally satisfied with "it just works" answer =)  Thank you for any help! =)


I have 2000 questionnaires from respondents which ask 33 different questions about which issues are present in their lives - i.e. alcohol abuse, domestic violence, mental health, child abuse, learning difficulties etc.  Each question can only be answered yes/no (which I've re-coded as 1/0).  I'd like to use this dataset to start creating n profiles of respondents via which variables naturally cluster together e.g. (alcohol abuse and domestic violence), (mental health, child abuse, domestic violence), (alcohol abuse, learning difficulties) across some/all of the 33 differnt variables.   Is two-step clustering in SPSS the most suitable method of analysing these data to identify say, 5 key cluters?  Thanks! :)

(This question is an edited version of a question I  which one user recommended would benefit from more focus).  I have 2000 questionnaires from respondents which ask 33 different questions about which issues are present in their lives - i.e. alcohol abuse, domestic violence, mental health, child abuse, learning difficulties etc.  Each question can only be answered yes/no (which I've re-coded as 1/0).  I'd like to use this dataset to start creating n profiles of respondents to define which variables naturally cluster together e.g. (alcohol abuse and domestic violence), (mental health, child abuse, domestic violence), (alcohol abuse, learning difficulties) across some/all of the 33 differnt variables.    indicates that hierarchical cluster analysis is not appropriate for a dataset of this scale/type due to sensitivity of the position of how data is sorted in the dataset, and recommends two-step cluster analysis instead.   Consequently, I'd be really interested in your input on whether hierarchical, two-step or other methods are most appropriate for exploring clusters of responses that natually associate together using a binary dataset.


In a question  was another question     My question is, why this direction and not the opposite?   This part of the post received no attention and so I ask it here explicitly.

At school I learnt the  to remember the resulting direction of different phenomena, such as geometrical cross products, mechanical torque, or the direction a screw will move when turning it. This directions are however decided by humans, and we could have easily defined the directions in the opposite way.  However the right hand rule also predicts phenomena which is not arbitrarily set by humans, but is intrinsic to the nature. If you have a coil in which you put some current, and the nature creates a magnetic field in a direction perpendicular to it, the direction depends on the right hand rule.  My question is, why this direction and not the opposite? Nature tends to be symmetric and not have apparent preferences for two equal options, so in a so why is one direction preferred over the other one? Why doesn't a "left hand" rule apply?


I can't remember when I read it - but likely the 70s. The young boy was so enamoured with travelling to the Mars that he built his own ship (which I think was box shaped) and flew there and came back.  That's all I remember. I'd like to get it for my kids now if anyone can remember it.

Probably in the late 1960s or early 1970s I read a book the general plotline of which was: a teenage boy builds his own spacecraft that operates by pulling and/or pushing gravity. He takes the home-built craft to Mars where he is stranded when one of the vacuum tubes in the device burns out.  I read the book probably 40 years ago so publication most likely 60s or earlier. A key component of the gravity gadget was a vacuum tube, so that almost certainly pens it in the 50s. Doubt if it was from foreign source, the writing was quite American biased.   I think he traveled alone, but that follow up question made me think his girlfriend might have gone with him.  It has been too many years for that detail to be remembered.   Light sci fi, nothing dark in the storyline. Situational jeopardy, no bad guys. I hate to spoiler the ending just in case someone wants to read it, but I can add if it would help.  OK. It was suggested I include the ending, so (SPOILER ALERT!!!)      After being stranded and surviving quite well, a team from earth arrives to look for him.  A member of the expedition was either his mother (I think) or his father.  What happened was, back home they figured out what he had done, but were unable to duplicate the technology.  And the space agency REALLY wanted that drive.  So the "rescue" mission was really just to try to recover the technology, as they had never expected to find him still alive. Surprise surprise...


Given an AND gate, an OR gate, and inverters as needed, design an SR flip flop with S and R active low (0).   I understand that to make such a flip flop, I would have to place inverters on the circuit so that the AND and OR gates behave like NOR gates, as NAND with S=0, R=0 would lead to a race condition. However, I have no idea how I would place inverters in such a way for it to behave like NOR gates.

I started studying flip-flops recently and I am stuck at this point: At some video tutorials, people explain the SR flip-flop like this:  So they use NAND gates, producing a transition table like this: |     t     | t+1 |  S  |  R  |  Q |  0  |  0  |  INVALID |  0  |  1  |  1 |  1  |  0  |  0 |  1  |  1  |  ?  However, some other people explain the SR flip-flop using NOR gates:  (source: ) which has a different transition table. Are both correct? Why do both exist?


I need to retrieve Table Names from Linked Oracle Database which is on Linked Server with Microsoft SQL Server.  e.g. I can get table names in SQL Server using:  SELECT TABLE_NAME, COLUMN_NAME  FROM INFORMATION_SCHEMA.COLUMNS  WHERE COLUMN_NAME LIKE '%TELEPHONE%'   but, I need Oracle Code.  I am using Microsoft SQL Server with a linked server to Oracle.

How do I query an Oracle database to display the names of all tables in it?


I installed Ubuntu 12.04 and now I want it deleted from my computer. I installed Ubuntu on a USB stick so I could dualboot my HP with windows 7 but now I want it removed. How do I do this?

I have absolutely no experience with Linux, and I desperately need to get my computer back up and running again with Windows.  How do I remove Ubuntu and reinstall Windows?    Editor's note: many of the answers are about removing Ubuntu from dual-boot but keeping Windows (which is a bit complicated), while other answers are about removing Ubuntu from single-boot (which is easy: basically just format the disk while installing Windows). The question as written is ambiguous between dual-boot or single-boot.


I am planning to migrate from my Sony DSC-HX1 bridge camera (28-560mm) to Canon EOS 800D.   Now I had learned that 'x' based zoom values are not applicable to DSLR's and I am lost with all the mathematical calculations, so my questions is:  What lens will provide me all capabilities of my earlier bridge camera like shooting Macro, landscape, portraits, zoom range etc. effectively?

What is the rule to convert the 'mm' notation to the 'optical zoom' notation? I searched a bit and found this one:  optical zoom = maximum focal length / minimum focal length   For example a 18-55mm lens would have a 3x optical zoom, and a 18-200mm lens would have a 11x optical zoom. Is that right?


Is there any difference between defining variables:  var p_tr1 = $('

') $p_tr = $('

')   i'm using netbeans, and variables have different highlighting.  I looked through FF debugger and found that variables are equals

I quite often see JavaScript with variables that start with a dollar sign. When/why would you choose to prefix a variable in this way?  (I'm not asking about $('p.foo') syntax that you see in jQuery and others, but normal variables like $name and $order)


My computer originally had Windows 8 on it.  I completely reformatted my laptop and put Ubuntu 14.04 on it.  I tried using wine but It won't run my Technic launcher for Mine Craft.  I also can't get the Linux version of the Technic launcher to work.  So, I want to reinstall Windows 8 beside the Ubuntu so I can use the 8 for gaming and the Ubuntu for the rest of it.

I have Ubuntu on my laptop. Now I want install Windows 7 in a dual-boot. How can I do this? I can't lose my Ubuntu files, and I'm afraid that I might break . Go  for UEFI only!


Let $A$ be an $n\times n$ complex matrix with $trace(A)=0$. We need to Show that $A$ is similar to a matrix with all $0'$ s along the main diagonal.  What I thought: $A$ is not zero matrix, also $A\ne cI$ for any $c\in\mathbb{C}^*$  so $\exists v\in \mathbb{C}^n$ which is not an eigen vector of $A$, then I thought of taking a basis whose first two vectors are $v,Av$ and then with respect to this basis what will be the matrix $A$?  Thanks for helping.

Prove that if $A$ is a square matrix and $\mathrm{Tr}(A)=0$, then there exists an invertible matrix $R$ such that the matrix $T=R^{-1}AR$ has all entries on its main diagonal equal to $0$.   It seems like the formula $A=S\Lambda S^{-1}$, but maybe it does not help.  Thanks so much.


When $\theta$ is very small why $\sin \theta$ is similar to $\theta$ and $\cos\theta$ similar to $1$? Is it related to limits or we can prove it simply by using diagrams?

What is the reason that  for $x<0.5$, $\sin(x)\approx x$?  Are there more known properties of these kind for other trigonometry functions?


If these are the vertices for a parallelogram,   (0,0), (-1,3), (4,-5), (3,-2)  how do I find the area?  I know it's supposed to be a 2x2 matrix and I need to find the determinant for it but I don't know which columns of it to use. Am I supposed to draw it out?  Am I supposed to shift one of the vertices to?

I need to find the area of a parallelogram with vertices $(-1,-1), (4,1), (5,3), (10,5)$.  If I denote $A=(-1,-1)$, $B=(4,1)$, $C=(5,3)$, $D=(10,5)$, then I see that $\overrightarrow{AB}=(5,2)=\overrightarrow{CD}$. Similarly $\overrightarrow{AC}=\overrightarrow{BD}$. So I see that these points indeed form a parallelogram.  It is assignment from linear algebra class. I wasn't sure if I had to like use a matrix or something.


I am using a MacBook Pro Retina with US international keyboard layout, latest OS. Is there a way to change ˜ to produce ~ without pressing the space after it? And is there a way to configure ' to work the same way? Like I don't need accents so If I type 'a I want to get 'a and not á without the extra space key press.

I've been working on macs for a couple of years now, and recently switched jobs (Software dev). Before when I  was typing something like "e would not automatically merge into ë. This is really annoying in terminal And I don't know how to disable this as of now (I googled but not sure what I should be looking for). One of the most annoying things I encountered was when I need to go to my home dir in terminal (using tilde) when tying by default it will complete to ˜/ whilst I would like to see it act like before: ~/ which requires me to type an extra space.  I never need the auto completion for accents since I'll use the menu which opens when you hold the key instead.  Does anyone know what could cause and get rid of this behaviour.  My keyboard settings are US-Internation (which is normal in the Netherlands) and my MacBook is fully updated to El-Capitan.


Brief description: Randomly select two items from an array and then remove them from the array, and then randomly select one item from two already randomly selected items. I know this has probably been asked before, But all the answers I could find I didn't know how to apply to my code. Here is my code: string[] teams = { "Team 1", "Team 2", "Team 3", "Team 4", "Team 5", "Team 6",     "Team 7", "Team 8" };  Console.WriteLine("The available teams are: "); for (int i = 0; i < teams.Length; i++) {     Console.WriteLine(teams[i]); }  Random rnd1 = new Random(); int r1 = rnd1.Next(teams.Length); Random rnd2 = new Random(); int r2 = rnd2.Next(teams.Length); Console.WriteLine("Round 1: " + teams[r1] + " vs " + teams[r2]);  How can I make it so that the two teams will always be different, and so that I can do a Round 2 which will be another two different teams? Another thing that I need to do is to make it so that when the two teams are picked for a round (let's say it's Team 3 and Team 7) to randomly select out of those two teams so I can decide a winner. I've tried a bunch of things and none of it worked, I mostly need help with the first problem but if anyone can help with the second one as well that'd be appreciated.

What is the best way to randomize an array of strings with .NET? My array contains about 500 strings and I'd like to create a new Array with the same strings but in a random order.  Please include a C# example in your answer.


I need a german Stemmer processor for my Search API in Drupal 8.  seems to be the right choice, but I can't get it to work. Snowball Stemmer requires a library. I think it is the wamania/php-stemmer. It should be installed with composer but I am not familiar with composer. I tried following: composer require drupal/snowball_stemmer  But I am getting  [InvalidArgumentException]                                                                                Could not find package drupal/snowball_stemmer at any version for your minimum-stability (stable). Check the package spelling or your minimum-stability    I tried also: composer require drupal/snowball_stemmer --dev --ignore-platform-reqs  but getting the same error. How I can install Snowball Stemmer with a german library?

I've found ,  and  which are releated to my question, but no longer seem to apply since Drupal 8.1 and the deprecation of .  Also popular guides such as  appear to no longer apply as they also mention composer manager.   The other solution opposed to composer manager, alter the core composer.json file feels like too much core hacking and would probably break with every Drush update of Drupal core(?).  More specifically, I am attempting to update  from Drupal 7 to 8. I have created my composer.json file as follows:  {   "name": "drupal/views_vcards",   "description": "Allows creation of vCards using the fields provided by the Views module.",   "type": "drupal-module",   "license": "GPL-2.0+",   "homepage": "https://drupal.org/project/views_vcards",   "require": {     "maennchen/zipstream-php": "0.3.*"   } }   But if I put a composer.json file in my module folder, how do I make Drupal aware that that file is there, and how do I make sure the required zipstream-php library is downloaded?  Simply running composer update from the Drupal root does update a lot of Drupal dependencies, but it does not include the composer.json files that are in the modules folders. I also don't assume I should be calling composer install from inside all modules with dependencies.  How do I make Drupal aware of a module's dependency without using composer manager and/or hacking core?  UPDATE:  The  appears to have support a wildcard path:  {     "require": {         "wikimedia/composer-merge-plugin": "dev-master"     },     "extra": {         "merge-plugin": {             "include": [                 "composer.local.json",                 "extensions/*/composer.json" // < ---- THIS LINE             ],             "require": [                 "submodule/composer.json"             ],             "recurse": true,             "replace": false,             "merge-dev": true,             "merge-extra": false         }     } }   Why doesn't core merge modules/*/composer.json, that would solve everything right?  Update 2:  THe reasoning for not supporting this is covered in  (which also has been quiet for some time now).


I know it's impossible to hide source code but, for example, if I have to link a JavaScript file from my CDN to a web page and I don't want the people to know the location and/or content of this script, is this possible?  For example, to link a script from a website, we use:  <script type="text/javascript" src="http://somedomain.com/scriptxyz.js"> </script>   Now, is possible to hide from the user where the script comes from, or hide the script content and still use it on a web page?  For example, by saving it in my private CDN that needs password to access files, would that work? If not, what would work to get what I want?

I want to make a JavaScript application that's not open source, and thus I wish to learn how to can obfuscate my JS code? Is this possible?


In Java, I have heard time and time again that too much memory can impact performance negatively. When I state memory, I am referencing virtual memory. Specifically I hear this more often than not when it comes to java -xmx.   I understand assigning too much virtual memory and systems with a low amount of RAM, but other engineers I have talked with have told me that even on higher-powered machines, you still want to ensure xmx is not overzealous. Is there a standard calculation everyone uses to determine this information such as on a 16GB machine you only use 1/4 for xmx? 1/8th for page file? I ham having a hard time grasping why too much memory is a bad thing.   I have been searching all over the internet and so far my google-ninja skills have not been sufficient to find a good answer.  I have looked at  and this does not really appear to answer my question (or I am just slow and need to re-read it a couple of times). I understand that systems will pull a chunk of memory and reserve it for themselves and I understand increasing xmx if out of memory errors are appearing.   My understanding is that xmx should not just be given a higher memory number (ex. 8096) unless the application requires it. I fail to understand what is so bad about assigning (ex. 8096), even if the application runs fine with (ex. 4096) etc.

Does anyone have experience with using very large heaps, 12 GB or higher in Java?   Does the GC make the program unusable? What GC params do you use? Which JVM, Sun or BEA would be better suited for this? Which platform, Linux or Windows, performs better under such conditions? In the case of Windows is there any performance difference to be had between 64 bit Vista and XP under such high memory loads?


I have two different widgets on one of my pages. They both display posts, but from different categories. One widget has pagination. Now when I switch to another page, the 2nd widget doesn't display anything. I suppose this is due to some pre-filtering done on the new page, resulting in no posts of the 2nd widget's target category being in the post list. Like e.g. all posts from the 2nd widget's category would be on page 1, so they are not available on page 2 since the post query/fetch WP does ahead of loading my page has already skipped them.

Could I theoretically use multiple php code areas / widgets in a page, each doing their own posts query and fetching with wp_query and get_posts() and use a page template that has no post loop?


In gravity, a particle mass $m$ is in linear motion on the x axis with a mass $M$ at the origin. Initially $v_0$ velocity and position $x_0$. After time delta T, what is the new position and velocity, $v_1$ and $x_1$? I have a degree in physics from 50 years ago and have forgotten how to solve this!

Two particles with initial positions and velocities $r_1,v_1$ and $r_2,v_2$ are interacting by the inverse square law (with G=1), so that  $$ {d^2r_1\over dt^2} = - { m_2(r_1-r_2)\over |r_1-r_2|^3} $$ $$ {d^2r_2\over dt^2} = - { m_1(r_2-r_1)\over |r_1-r_2|^3} $$  (the inverse square law along the line of separation). What is the complete solution of these differential equations? What is the position of the two objects as a function of time?  After reading a lot on Wikipedia, I've come to the definition of center of mass and relative coordinates:   $$R(t) ~=~ \frac{m_1 r_1 + m_2 r_2}{m_1+m_2}$$  $$\ddot{r}(t) r(t)^2 ~=~ (m_1+m_2)G$$  Where $R$ is the center of mass, and $r$ is the displacement between the particles... Is this correct? How do I proceed to solve the differential equation?


I have a paper that I wrote in Word with accompanied math equations (for my undergraduate level research paper for mathematics degree) and I just am not at all familiar with LaTeX. I was wondering what resources I could use to get this paper re-written into LaTeX. I will never need to use the program again, so I was really looking for someone who could convert it for me. I would be interested in paying.   If hiring somebody for this isn't an option, could someone maybe help me write it? This program seems like a lot of work where I only have 4 days to get it re-written.

I am a final year graduate student and I have my thesis (about 350 pages) in Microsoft Word format. I would like to convert the document into a LaTeX "camera" ready PDF. Is there any easy way to do this? I am very new to LateX..


Suppose that $f$ is a uniformly continuous function defined on $\mathbb Q \cap [0,1]$. Show that there is a unique continuous function $g$ defined on $[0,1]$ so that $$g(x)=f(x) \text{ for every } x \in \mathbb Q \cap [0,1].$$    Not sure what I am supposed to do here. I've seen answers where a sequence was defined to converge to a point $x \in \mathbb Q \cap [0,1]$ but I'm not understanding why we are doing this.  I know that continuity preserves converges of sequences and uniform continuity preserves Cauchy sequences.  Any help on getting started with this exercise?

Working on the following problem from Munkres:      Let $(X, d_{X})$ and $(Y, d_Y)$ be metric spaces; let $Y$ be complete.   Let $A \subset X$. Show that if $f:A \to Y$ is uniformly continuous,   then $f$ can be uniquely extended t a continuous function $g:  \overline{A} \to Y$, and $g$ is uniformly continuous.   If there exists such an extension, it must be unique, and $f(x) = \lim_{n \to \infty}f(x_n)$ for $x_n$ a sequence in $A$ converging to $x \in \overline{A}$. To show this limit exists, let $x_n \to x$, then $f(x_n)$ is Cauchy, since uniformly continuous functions take Cauchy sequences to Cauchy sequences. Then $f(x_n)$ converges by completeness, and I claim it converges to $f(x)$.  Now, to show $g$ is uniformly continuous, I kind of brute-forced it, and I was wondering if anyone had a more elegant method. (I consider the proof up to now pretty elegant.) What I did was: Suppose for contradiction that $\exists \epsilon >0$ s.t. $\forall \delta >0\,\, \exists x_\delta, y_\delta \in \overline{A}$ s.t. $d(x_\delta, y_\delta)< \delta$ and $d(g(x_\delta), g(y_\delta))> \epsilon$. Let $\delta := \delta_{\epsilon}/2$, where $\delta_\epsilon$ is taken from the uniform continuity of $f$. Now $d(g(\cdot), g(\cdot))$ is continuous...in particular, it is continuous in each variable separately. Therefore we can vary $x_{\delta}$ and $y_{\delta}$ a little bit, to get $x^*,\, y^* \in A$ such that $d(x^*, y^*)<\delta_{\epsilon}$ and $d(f(x^*), f(y^*))>\epsilon$, a contradiction.   Does anyone know a more elegant method to show the uniform continuity?


when I start my computer it asks to boot into windows 8 or EasyRE, how to remove the EasyRE entry from bootloader and directly boot into windows 8 without being asked to select OS

How do I modify the boot menu in Windows 8?  There's an entry that I want to remove for a "boot from VHD" option that no longer exists.


I'm only asking this out of curiosity since I've seen posts/discussions about getting into "top" graduate programs etc. This mentally (wanting to get into a "top" ranked program) makes sense (depending on one's priorities) for undergraduate study, since the selectivity is what gives the degree its "prestige."  This may also hold true for law or medical school programs where rankings may reflect the level of training one receives and/or directly affect internship/residency opportunities etc. However, I'm not sure how this would apply to a research degree. For example, in masters or PhD research programs, you're applying to conduct research under the auspices of a specific advisor. Thus, it seems that alignment of research interests and personal compatibility should be prioritized over "rank" of the program. Obviously one still has to meet certain admissions criteria regardless of the program they're applying to, but it doesn't make sense (to me anyway) to rank/judge research oriented graduate programs the way one would an undergraduate or "professional" program (i.e medical or law school etc). Also, will the quality of one's graduate education or future academic career opportunities be affected by the rank of the program? Personally, my main priorities are location combined with compatibility of an advisor. However, I was curious as to what criteria are used to rank graduate programs and why would one prioritize rank of program over other factors.

What I'm trying to understand is, to what degree does the status/rank of the University (where one completes his/her Ph.D) matter while shaping his/her career after graduation? I would like to know the weight given to one's school in both the following cases:   While applying for post-docs/faculty positions in academia While applying to industrial research labs   For instance, I've read on some forums (I can't locate the link now) that while considering prospective applications for tenure-track faculty positions, very few Universities accept a candidate who has completed his/her Ph.D from a lower ranked school having a lesser "brand" value, irrespective of the fact whether he/she has published equally original work as his/her counterpart from an Ivy league college. How much truth is in this statement? It would be really great if someone already in academia, either as a newly-accepted faculty or someone on the Faculty Hiring committee could share their experiences/statistics on this regard. I'm simply interested to know the answer, without commenting at all on whether such a practice is justifiable.  Similarly, what about recruitment to internationally acclaimed research labs (like  or ) - what importance do they place on the pedigree of a candidate's college, before taking into consideration what they published ?  I'm personally interested in answers related to the field of Computer Science (theory), but the question is applicable to any prospective grad student in any discipline in my opinion. Feel free to share your personal experiences post-Ph.D in detail, as that would give me (and future viewers of this question) about what its like to carve a career once you are out of school!


I am unable to upgrade Ubuntu 14.04 or install any new software as I always get the following error:  Reading state information... Done You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies:  libc6-dev : Depends: linux-libc-dev but it is not going to be installed  libnss3 : Breaks: libnss3:i386 (!= 2:3.19.2-1ubuntu1) but 2:3.26.2-0ubuntu0.14.04.3 is to be installed  libnss3:i386 : Breaks: libnss3 (!= 2:3.26.2-0ubuntu0.14.04.3) but 2:3.19.2-1ubuntu1 is to be installed  libnss3-nssdb : Depends: libnss3 (= 2:3.26.2-0ubuntu0.14.04.3) but 2:3.19.2-1ubuntu1 is to be installed E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).   I tried running   sudo apt-get -f install   but it doesn't work as I get the following error in output:  Reading package lists... Done Building dependency tree        Reading state information... Done Correcting dependencies... Done The following packages were automatically installed and are no longer required:   account-plugin-windows-live kde-l10n-ar kde-l10n-engb libntdb1 libupstart1   linux-headers-3.16.0-30 linux-headers-3.16.0-30-generic   linux-image-3.16.0-30-generic linux-image-extra-3.16.0-30-generic   python-ntdb python-pexpect python-renderpm python-reportlab   python-reportlab-accel Use 'apt-get autoremove' to remove them. The following extra packages will be installed:   libnss3 The following packages will be upgraded:   libnss3 1 upgraded, 0 newly installed, 0 to remove and 146 not upgraded. 3 not fully installed or removed. Need to get 1,126 kB of archives. After this operation, 30.7 kB disk space will be freed. Do you want to continue? [Y/n] Y Get:1 http://archive.ubuntu.com/ubuntu/ trusty-updates/main libnss3 amd64 2:3.26.2-0ubuntu0.14.04.3 [1,126 kB] Fetched 1,126 kB in 5s (214 kB/s)     (Reading database ... 292354 files and directories currently installed.) Preparing to unpack .../libnss3_2%3a3.26.2-0ubuntu0.14.04.3_amd64.deb ... Unpacking libnss3:amd64 (2:3.26.2-0ubuntu0.14.04.3) over (2:3.19.2-1ubuntu1) ... dpkg: error processing archive /var/cache/apt/archives/libnss3_2%3a3.26.2-0ubuntu0.14.04.3_amd64.deb (--unpack):  trying to overwrite shared '/usr/share/doc/libnss3/changelog.Debian.gz', which is different from other instances of package libnss3:amd64 dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Errors were encountered while processing:  /var/cache/apt/archives/libnss3_2%3a3.26.2-0ubuntu0.14.04.3_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1)   Edit: There is an error icon appearing just next to clock in top status bar, which contains text      An error occurred, please run Package Manager from the right-click menu or apt-get in a terminal to see what is wrong. The error message was: 'Error: Brokencount > 0'. This usually means you installed packages have unmet dependencies.   By clicking on Show Updates in this icon menu I get window (New Important Security and hardware support update.      WARNING: Security updates for your current hardware Enablement stack ended on 2016-08-04    By trying to click install on this window, it still gives me an error installing.  How can I fix my system so that I can upgrade?

For example:  $ sudo apt-get install curl Reading package lists... Done Building dependency tree Reading state information... Done You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies: bsh : Depends: libjline-java but it is not going to be installed groovy : Depends: libjline-java but it is not going to be installed rhino : Depends: libjline-java but it is not going to be installed E: Unmet dependencies.   Try 'apt-get -f install' with no packages (or specify a solution).   I get the same or similar errors when I attempt to install clojure1.3, leiningen, and several other packages.   When I try the suggestion made in the error message, this is what happens:  $ sudo apt-get -f install  Reading package lists... Done Building dependency tree        Reading state information... Done Correcting dependencies... Done The following packages were automatically installed and are no longer required:   diffstat linux-headers-3.2.0-26-generic linux-headers-3.2.0-26 dh-apparmor dkms html2text libmail-sendmail-perl libsys-hostname-long-perl Use 'apt-get autoremove' to remove them. The following extra packages will be installed:   libjline-java Suggested packages:   libjline-java-doc The following NEW packages will be installed:   libjline-java 0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded. 23 not fully installed or removed. Need to get 0 B/72.0 kB of archives. After this operation, 129 kB of additional disk space will be used. Do you want to continue [Y/n]? Y (Reading database ... 226243 files and directories currently installed.) Unpacking libjline-java (from .../libjline-java_1.0-1_all.deb) ... dpkg: error processing /var/cache/apt/archives/libjline-java_1.0-1_all.deb (--unpack):  trying to overwrite '/usr/share/java/jline.jar', which is also in package scala 2.9.2-400 Errors were encountered while processing:  /var/cache/apt/archives/libjline-java_1.0-1_all.deb E: Sub-process /usr/bin/dpkg returned an error code (1)  $ sudo apt-get upgrade Reading package lists... Done Building dependency tree        Reading state information... Done You might want to run 'apt-get -f install' to correct these. The following packages have unmet dependencies:  bsh : Depends: libjline-java but it is not installed  groovy : Depends: libjline-java but it is not installed  rhino : Depends: libjline-java but it is not installed E: Unmet dependencies. Try using -f.


I'm struggling to decide whether to jettison use of the word fact, because the definition appears to be not solid enough to support continued usage. What do I mean by that? Look at one "meaning ladder" (taken from Random House via ) among several on the same page:  fact  something that actually exists: Your fears have no basis in fact. something known to exist or to have happened. a truth known by actual experience or observation; something known to be true. something said to be true or supposed to have happened. an actual or alleged event or circumstance, as distinguished from its legal effect or consequence.   This definition marches us from something that exists to something that is merely supposed to be true to something that may be "actual or alleged." (And yes, I am aware that dictionaries don't dictate the meanings of words; they record meanings from usages. And the meanings of this word as it is used and recorded in English seem to be antagonistic toward each other.) What are we to do with all this? Does a fact require the modifier true to be judged genuine? When we preface a statement with "in fact" don't we mean What follows is the truth? The aforementioned dictionary certainly thinks so:  in fact, in truth; really; indeed: They are, in fact, great patriots.  Here fact and truth are equated absolutely. So I'm wondering: how do we distinguish between what is a fact in the sense of absolute truth and what is a fact of a lesser order? Other words can have many shades of meaning, but this one seems somehow like it shouldn't. So if I hear the word fact without hearing true before it, does it even deserve the term? A cautionary note I'm not really looking for a discussion of truth in the philosophical sense. The scope of this question is limited to the meaning of a word in English, not the meaning of an absolute concept as rational beings can or should understand it. What I'm really after, as I mentioned in a comment, is whether the adulteration of this particular word renders it, ultimately, meaningless, and therefore something to be avoided. In conclusion, I offer this quote from Howard K. Zinn, from his Afterword to A People's History of the United States:  But there is no such thing as a pure fact, innocent of interpretation. Behind every fact presented to the world—by a teacher, a writer, anyone—is a judgment. The judgment that has been made is that this fact is important, and that other facts, omitted, are not important

I've seen this so many times and it drives me crazy. The latest was the actor Paul Giamatti setting some story straight in the press about him: "It's unfortunately an incorrect fact about me and it's all over the place."  I've seen this written so many times, in magazines, books, but surely a fact is, by definition, true. So there cannot be any such thing as a "false" fact. Right?


Sorry for the structure and maybe some mistakes in the post - I'm not a Mathematician and not a native English speaker, so I will use Google Translator + Grammarly for help. Please, if you want and can - help me to find an answer to this sequence of questions:  Does an inverse number to zero (null) exist? 1.1) If yes - what is it? 1.2) Or/And - is the one solution or several? 1.3) Or/And - is there an equal or different weight of these solution/-s in mathematical society? Does a meta of number exist?  My own naive thoughts (briefly and simply): About 1 question: if we can imagine that "zero" (null) is a mathematical concept of "nothing", so maybe exists a mathematical concept of "everything"? Maybe if I call "zero" (null) an "Absolute Emptiness", so maybe we should create "Absolute Fullness"? Remark - I don't mean any sort of infinities, like infinity small values (maybe they called "infinitesimals") and their opposites - infinite big values (plus or minus, I suppose it doesn't matter in this context, and don't know their right definitions, sorry) - because these entities have values and they have some sort of scope of properties, let's call them "Relatives". About 2 question: if we can operate not just different values, but also their "Absolute Emptiness" (which for me looks confusing, because if I have the right understanding, we trying to operate by "nothing" with serious faces =))) - maybe there is an existing core property of a number, lets call it's "meta". This "meta" means the existence of some object, which we want to operate. Or maybe, it would be useful to separate operating of "Absolutes" (like only two objects - "zero" (null) and it's inverse) and "Relatives" which has a range from infinity small number (no matter of sign) to infinity big number (also not matter of sign)? If we do this separation, maybe we displace problems like division by zero or just will look at the problem from another angle - because it seems like when we dividing the non-zero value by zero (or do other 3 arithmetic operations) we work with 2 types of entities/properties ("Relative" and "Absolute") which maybe require a different approach, because for my understanding (of course with Dunning–Kruger effect xDD) there is no fundamental/crucial/disbalance problem to divide non-zero infinity small/big/mediocre value by non-zero infinity small/big/mediocre value (or do other 3 arithmetic operations, or other general operations), are you agree? It would be so nice if you give me answers to those questions because I even don't how trivial these questions are. P.S. If there are no one/multiple clear answers, maybe you can suggest a path/sequence of books (from zero to goal) which I must read/understand and that is will help me solo find answers to the questions above. Thanks you in advance.

In the definition of a field one of the required properties is that  every element other than zero has a multiplicative inverse.  It's vague whether the zero is forced not to have an inverse or not, as in is the property  every element other than zero has a multiplicative inverse and zero does not  or  every element other than zero has a multiplicative inverse and zero may or may not?  Regardless, what differences would occur if we adopted one definition as opposed to the other?


I've installed IBM Installation Manager on Ubuntu 18.04 but when I started the following message pops up: Could not find the program 'gksudo'  I've tried to install it by running the commands below: sudo apt install gksudo sudo apt install gksu  But they don't seem to be a part of Ubuntu anymore. I've also read it somewhere. How to workaround the problem? Adding the universe repository didn't help: $ sudo add-apt-repository universe 'universe' distribution component is already enabled for all sources.  $ sudo apt update Hit:1 http://dl.google.com/linux/chrome/deb stable InRelease Get:2 http://security.ubuntu.com/ubuntu bionic-security InRelease [88,7 kB]                                                                                Hit:3 http://ru.archive.ubuntu.com/ubuntu bionic InRelease                                                                                Hit:4 http://ru.archive.ubuntu.com/ubuntu bionic-updates InRelease                                                                                Hit:5 https://download.docker.com/linux/ubuntu bionic InRelease                                                                                Hit:6 http://ru.archive.ubuntu.com/ubuntu bionic-backports InRelease                                                                            Hit:7 https://repo.skype.com/deb stable InRelease                                                                                Hit:8 https://deb.nodesource.com/node_12.x bionic InRelease                                                              Fetched 88,7 kB in 1s (94,6 kB/s)                   Reading package lists... Done Building dependency tree        Reading state information... Done All packages are up to date.  $ sudo apt install gksu Reading package lists... Done Building dependency tree        Reading state information... Done Package gksu is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  E: Package 'gksu' has no installation candidate  I also tried to solve it in almost the same way suggested here:  But I created a bash script with the command suggested there (pkexec ...)and created a link /usr/bin/gksudo to it. After that I started the IBM installation manager. The password dialog appeared, but after I entered the password the dialog was closed and nothing else happened. As a workaround I start the IBM Installation Manager in terminal by issuing the command: sudo /opt/IBM/InstallationManager/eclipse/IBMIM

I've read a lot of threads about gksu being removed from many Linux flavours, including Ubuntu 18.04.  Many state that gksu is an abomination and no user should ever need to use anything like it.  I have 2 examples where, as far as I know, I must have something that allows me to run as root (not just for editing files).    First, I have a need to start mysql only after an encrypted folder is opened on (GUI) command.  This means having a script run by the encryption system that starts the mysql service.  That has to be done as root, so I use gksu in that startup script which asks me for a password.  How else can I start a service from a GUI system?  I also run Ubuntu system backups as root, otherwise many system files can't be backed up.  So the desktop file uses gksu to start the backup.  pkexec looks complicated, needing policy files.  Is that the only alternative, and if so, why is it any safer?  Other answers to similar questions don't seem to address individual issues that people have now that gksu is no more (or harder to find...).  I think such questions from non-expert users would benefit from more detailed answers.  I now have some, and so would like to answer my own question.


I'm new to Blender and am experimenting using it to design a landscaping project. I have a DXF file with contour lines for the land and have managed to import these into Blender. My aim is to have a full surface that reflects the site, and where I can start manipulating the slope and adding shapes onto it.  I now have a series of lines with heights, but that are not connected to each other and don't have an edge around them. After a long time trying to just join the edges using a combination of selecting them and choosing "Connect vertex path" or "Merge vertices > at center" (when connect didn't work) I thought maybe I'd be able to create a plane from it. However this only created small patches of planes so I'm guessing I've done something wrong. I was thinking as a next option I could just create a plane of the same size underneath it and manually drag each point up to match a point on one of the contour lines. This would probably take quite a while - is there any better option out there?

Hi Guys,  I have a set of points in 3D. How can I convert this into a surface ?


I need help with the math equivalent for excel formula PMT(). There is an answer @ below thread... BUT nothing is mentioned with regards to the option parameters of PMT() i.e. FV and Type. Can anyone please guide with math equivalent with FV?

I need to create a JavaScript form that does the same calculation as this =PMT() function.   mortgage = 220000 rate= 4.75% term = 30   The example formula I have is =PMT(4.75%/12,30*12,220000*-1)  What would be the equation for this function? I tried to look up this function but it doesn't explain it very well.