Is ADD 1 really faster than INC ? x86
INC instruction vs ADD 1: Does it matter?
Help center still has the guidance about old Favorite tags Combine 4 cells in a table Here is a simple table.  I want to merge 4 cells. I want to combine the three "this" cells area in this table. I thought I have to use multirow and multicolum at same time. However, I could not find how to use it.  If possible, could you post the modified LaTeX source code?     My LaTeX code:  \documentclass{article} \usepackage{multirow}% http://ctan.org/pkg/multirow \usepackage{hhline}% http://ctan.org/pkg/hhline \begin{document}  \begin{table}[ph] \begin{center} \begin{tabular}{c|c|c|c|c} \hline \multirow{2}{*}{Raaa (k)} &amp; \multicolumn{4}{c}{C ()} \\ \hhline{~----}  &amp; 3.3 &amp; 2.5 &amp; 1 &amp; 0.5 \\ \hline \multirow{2}{*}{Raaa (k)} &amp; \multirow{2}{*}{this} &amp; this &amp; 0.5 &amp; 0.6\\ \hhline{~~~--}            &amp;                       &amp; this &amp; 0.7 &amp; 1.2 \\ \hline \end{tabular} \caption{R, C ripple size} \label{T:peak} \end{center} \end{table} \end{document} How to get icons in Safari favorites (aka favicons) to display correctly? I am using Safari on macOS Sierra. I have added several commonly-used sites to my favorites section, like so:    (there are 10 icons, and all but 2 of them are displayed as the proper, correct icon from the site. For example, the Wikipedia icon has the large W icon. However, for Google Drive and Gmail, the icons are just big, ugly, generic G's)  I would like for the two Google sites to correctly display their icons as well. At first, I thought it was because all 8 of the "correctly displayed" sites had successfully configured their "Safari settings" or something like that, while Google failed to do this (although this doesn't sound too plausible).  However, if I instead go to the top menu in Safari, click Bookmarks > Show Bookmarks, I get the following:    Strangely, this time, the two Google sites do have correctly displayed icons, while it is instead three other sites (out of the 10) that aren't displayed: namely Wikipedia, Amazon, and New York Times.  So it seems that there are two sets of icons, "big" and "small", and for big icons, Google Drive and Gmail are not displayed correctly, while the other 8 are, and on the other hand, for small icons, Google Drive and Gmail are displayed correctly, while Wikipedia, Amazon, and NYTimes are not.  I actually don't care too much about the small icons, but I would really like for all the big icons to display correctly. How can I do that? What is the accepted/most commonly used way to manipulate dynamic (with all dimensions not known until runtime) multi-dimensional arrays in C and/or C++.  I'm trying to find the cleanest way to accomplish what this Java code does:  public static void main(String[] args){  Scanner sc=new Scanner(System.in);  int rows=sc.nextInt();  int cols=sc.nextInt();  int[][] data=new int[rows][cols];  manipulate(data); }  public static void manipulate(int[][] data){    for(int i=0;i&lt;data.length;i++)    for(int j=0;j&lt;data[0].length.j++){          System.out.print(data[i][j]);           }     }   (reads from std_in just to clarify that dimensions aren't known until runtime).  Edit:I noticed that this question is pretty popular even though it's pretty old.  I don't actually agree with the top voted answer.   I think the best choice for C is to use a single-dimensional array as Guge said below "You can alloc rowscolssizeof(int) and access it by table[row*cols+col].".  There is a number of choices with C++, if you really like boost or stl then the answers below might be preferable, but the simplest and probably fastest choice is to use a single dimensional array as in C.  Another viable choice in C and C++ if you want the [][] syntax is lillq's answer down at the bottom is manually building the array with lots of malloc's. How to only append to clipboard (but not overwrite current data)? I am using Ubuntu 16.04, with Gnome 3.18. Using extensions I have gotten rid of the dash panel and only use the Applications Menu in the upper left-hand corner of the screen. (I don't have Unity.) What I can't figure out is how do you add a new program, move software around to different categories, and create new categories?  Also, any keyboard shortcut to access the Applications Menu? How can I say this? Let $E$ be a finite dimensional vector space over field $\mathbb R$ with $E^*$ as the dual space of $E$.($\dim E=n$)   $\Omega^P(E):=\{ \alpha\colon \overbrace{E\times\cdots\times E}^{p- times}\rightarrow \mathbb R\  \ , \alpha \text{ is alternating multilinear map}\}$ $\Omega^P(E^*):=\{ u\colon \overbrace{E^*\times\cdots\times E^*}^{p- times}\rightarrow \mathbb R\  \ , u \text{ is alternating multilinear map}\}$  I wish to prove that there exist an $\textbf{unique}$ bilinear form $B\colon \Omega^p(E^*)\times\Omega^p(E)\rightarrow\mathbb R$   such that for all $ f_i\in E^* \ , u_j\in E^{**}\simeq E \qquad  i,j=1,\cdots,p$, it has the following rule:  $B(u_1\wedge\cdots\wedge u_p,f_1\wedge\cdots\wedge f_p)=\det[f_i(u_j)]$.  $\wedge$ is wedge product between alternating maps i.e. $\alpha\wedge\beta(v_1,\cdots,v_{p+p})=\dfrac{1}{p! p!}\displaystyle\sum_{\sigma\in S_{p+p}}sign(\sigma)\alpha(v_{\sigma(1)},\cdots,v_{\sigma(p)})\beta(v_{\sigma(p+1)},\cdots,v_{\sigma(p+p)})$  How can I do this? All matrices which commute with all $2\times 2$ matrices I would like to find all matrices which commute with all $2\times2$ matrices.  I started solving problem in this way:    1) I have this matrix $A$ with real numbers: $$A=\left[\begin{array}{cc}a &amp;b\\c &amp;d\end{array}\right]$$ 2) Matrix which commute with matrix $A$ is matrix $B$: $$B = \left[\begin{array}{cc}e&amp; f\\ g &amp;h\end{array}\right]$$ 3) When i solve the equation $AB=BA$, I get this: $$\left[\begin{array}{cc}ae+bg&amp;af+bh\\ce+dg&amp;cf+dh\end{array}\right]=\left[\begin{array}{cc}ea+cf&amp;eb+df\\ga+ch&amp;gb+dh\end{array}\right]$$  How I can get the general look of wanted matrix? Having different horizontally  distributed equations inside an align environment, only lines are numbered, but not individual equations.    How can the left equations be numbered using subequations? See also the question   \documentclass{article} \usepackage{amsmath} \begin{document}   \begin{subequations}     \begin{align}        %\label{a}         a &amp;= a ,&amp;       \label{b}         b &amp;= b ,\\       %\label{c}         c &amp;= c ,&amp;       \label{d}       d &amp;= d .     \end{align}   \end{subequations} \end{document}     The solution should be able to either:    attach a label to the left equations, or modify the labels on the right to read (1a,b) and (1c,d)    I couldn't find anything in the documentation of amsmath or other packages. Proof of centripetal acceleration formula ($a_c = v^2/r$) for non-uniform circular motion The formula for centripetal (radial) acceleration is well known, and there exist many proofs for it: $$||a_c|| = \frac{||v||^2}{r}$$  However, all the proofs I've seen rely on the fact that it is uniform circular motion and the magnitude of the tangential velocity vector does not change. For instance, take the classic proof using similar triangles — the similarity can only be established if the final tangential velocity vector and the initial one are of the same length.  In addition, take  calculus based proof from Khan Academy, outlined as follows:     For this proof to work, $(d\theta / dt)$ must be considered a constant, $\omega$, that does not depend on time. In the case of non-uniform circular motion, however, this is not always true as since there exists a tangential acceleration along with a radial one, $\omega$ must depend on time and is not necessarily a constant value.  Intuitively I understand that the centripetal/radial acceleration depends only on the difference in orientation between two tangential velocity vectors, and that their magnitudes do not matter -- hence the formula intuitively holds true in the non-uniform case. However, how would you go about modifying either of the proofs presented so that they are still valid in this case? Or alternatively, is there another proof that holds valid even when there exists tangential acceleration?    As per the suggestion of one of the answers, I let $\omega$ vary with time and took its derivative as $\alpha(t)$. This is my work so far. Unfortunately, I am stuck after the last step.  \begin{align} \overset{\rightharpoonup }{p}(t) &amp;= r \cos (\theta (t))\cdot\hat{i}+r \sin (\theta (t))\cdot\hat{j} \\ \overset{\rightharpoonup }{v}(t) &amp;= -r \sin (\theta (t))\cdot\omega(t)\cdot\hat{i}+r \cos (\theta (t))\cdot\omega(t)\cdot\hat{j} \\ \overset{\rightharpoonup }{a}(t) &amp;= (-r \cos(\theta(t))\cdot\omega(t)^2 - r \sin(\theta(t))\cdot\alpha(t))\hat{i} \\ &amp;+ (-r \sin(\theta(t))\cdot\omega(t)^2 + r \cos(\theta(t))\cdot\alpha(t))\hat{j} \end{align}     From here on, $\theta(t)$ is represented as just $\theta$ for brevity   and clarity   $$\overset{\rightharpoonup }{a}(t) = -\omega(t)^2(r \cos\theta\cdot\hat{i} + r \sin\theta\cdot\hat{j}) -\alpha(t)(r \sin\theta\cdot\hat{i} - r \cos\theta\cdot\hat{j})$$ Is there a standard "never returns" attribute for C# functions? Can I add new methods to the String class in Java? Can I levitate an object without using an electromagnet? In Python, what are metaclasses and what do we use them for? Is there a proof of existence of time? It seems to me that there is no such thing as time. There  is only movement in the universe and we compare our own movement to a different object to have a sense of time. It can be a clock or a atomic vibration.  Does this view of time work within the current framework of phsics?  Do physicists have an explanation/proof about time's existence? In a world without air, I understand they definitely would. However, with drag taken into account, I think they wouldn't. Since the drag force varies proportional to the square of speed (ignoring the change in coefficient of drag with speed), wouldn't the total impulse due to drag on a bullet fired from a gun from a specific height horizontal to ground be higher than the total impulse on an identical bullet dropped from the same height with no horizontal velocity?  Also, when bullet spin is taken into account, the bullet fired from a gun should resist change in orientation; therefore, it should maintain a small but non-zero angle of attack, and also have a lift force, correct? Is momentum conserved in this situation? Suppose we have object A , which has momentum mv. Then it elastically collides with a wall, so it's momentum now -mv, So how is momentum conserved here ? I hope this isn't a silly question but I've been watching TNG and this bothers me.  The transporter 'pad' area is relatively small.  As a guess, maybe 12 people can fit on it.  But the vast majority of times it's being used by 2-3 people.  However, the transporter is able to beam people from anywhere on the ship to anywhere (within some distance I presume).  It's fairly common for them to perform a transport directly to the bridge.  So, why is there an actual room?    If a three man away team is to beam down to the surface of a planet - why do they have to walk all the way to the transporter room, then stand on the pad to get down there?  Why not simply beam them from where they are, to the surface.  The ship's computer is able to locate anyone on board. How to add indicator on a light switch to indicate the outdoor 3-way light is on? Have some carriage lights outside my garage that can be turned on from inside the house. It's common that the switch will get flipped and the lights will stay on when they're not wanted.  Is there some way I can add an indicator to the light switch so I can know if the light is on?  Note: the carriage lights are on a 3 way switch.