How to install the amd Catalyst drivers in Ubuntu?
What is the correct way to install proprietary ATI Catalyst Video Drivers (fglrx) directly from AMD?
Circle-Rectangle collision detection (intersection) How can I tell whether a circle and a rectangle intersect in 2D Euclidean space? (i.e. classic 2D geometry) QGIS area calculation differs when on the fly CRS transformation enabled When I open QGIS, add the layer, and calculate the areas of the shapefile via field calculator I get a different area than when I open QGIS and check "Enable on the fly CRS transformation" and calculate the area. This is despite making sure that the project and the layer have the same Coordinate system (same EPSG number). What am I doing wrong?   I have a shapefile with area calculations made with ArcGIS (not be me, the data was handed to me and I have no clue for which CRS the area was calculated with ArcGIS). The shapefile layer CRS is EPSG: 21781 (Switzerland). In QGIS, if I do not change the OTF settings and leave the project CRS as EPSG:4326 (WGS84) I get the same value as the ArcGIS area value. However, if I change the OTF before adding the layer to EPSG: 21781 I get different area values. As I understand this suggests that ArcGIS Area was calculated with the CRS EPSG: 4326.  First workflow:   open QGIS  project CRS: EPSG 4326  add layer  project CRS adapts automatically and is EPSG 21781 now  calculate $area with field calculator    Second workflow:   open QGIS  project CRS: EPSG 4326  Turn on OTF, set project CRS to EPSG 21781  add layer  calculate $area with field calculator    Step 5 of the first and second workflow DO NOT produce the same area. Does a photon exert a gravitational pull? rent a car, rent out a car, hire a car English not my native language. I'm trying to understand what would be correct in British English.  If I want to use a car for some time. I can say, "I want to rent a car". But from my knowledge there may be a  misunderstanding. I can say the same words if I want to give a car to someone to use for some time and I want to receive payment.  So what would be correct and not misunderstanding?   1) I want to use a car for some time = "I want to hire a car" 2) I want to give a car to someone to use for some time = "rent out a car"   Is my understanding correct? From this , I now understand the gradient to be the directional derivative that returns the steepest slope at a point. However, reading my textbooks, they all say that the gradient is normal to the tangent plane. In the above SE question, the gradient sounds like it should be parallel to a direction in the $xy$ plane, not actually up on the surface.   My question is therefore do I have a misunderstanding of the tangent plane, gradient or directional derivative?   In addition, I question how the gradient always passes through the origin or the $xy$ plane? If for instance in the graphic, the gradient had been another direction (say horizontal), then it wouldn't pass through the origin! In addition, the gradient of other points in the graphic would satisfy this example. Many thanks! Constrain to any 2 axes during transform? I want to be able to lock my translation/scale operations to two axes at a time, say xy, xz or yz. It currently takes two operations (one for each axis).  Example, say for a cylinder, I would like to reduce the radius. I currently have to scale on the x axis first, then on the y axis, or I have to manually input the scale values in the object properties panel.  This option is easily accessible in 3dsmax via the axis constraints command bar. Or I can click the intersecting area between the 3d manipulator of the axes in question and move in that plane. I have an area which is divided into several zones the borders of which I have defined as separate layers.  The layers are defined by sql queries on a postgis table of line segments joined with a table that says which segments are part of which zone boundaries.  What I want to do is produce a set of maps where each map is a zoom to layer extent for each zone and which has standard header, legend and scale (which will preferably vary with the zone but could be fixed across all maps).  My first attempt was to get a new composer for each map -- that worked but was rather tedious.  Next I tried producing one map and printing it and then deleting the map frame and going into qgis to zoom to the next layer extent and make the boundary visible then hopping back into the composer to load it in.  This worked more or less.  Map was fine, legend was OK because it was the same for all the maps and the zone name was easy to edit but the scale needed to be deleted and set up again for each map.  Next I looked at Atlas Generation.  The manual seems to assume that you know how it works and all you need is a reminder about the details (like so many software manuals ;)  It seems to assume that you have something that you are iterating over but I can't see how to make it work -- there is nothing to iterate over to get the layers.  Any suggestions welcome!!  :)  Russell Find all entire functions $f(z)$ such that $|f(z)|=1$ for $|z|=1$ Let $R$ be a Artinian commutative ring with $1 \neq 0$. If $I$ is prime, then $I$ is maximal. Prove: Let $R$ a Artinian commutative ring with $1 \neq 0$. If $I$ is prime, then $I$ is maximal.     I got stuck on this. I understand that every ideal is generated by finitely many elements. Here is my approach:  It's enough to prove the following implication: $$ R/I \ \text{is a domain} \quad \Rightarrow \quad R/I \ \text{is a field}$$ Then only finding an inverse is left. So let $x \in R$ in arbitrary. We have to find an inverse element of $x+I \in R/I$, that as an element y so that $x \cdot y \in I+1$. We denote $I = (x_1, x_2, \cdots, x_n)$.  Now I have to find y so that $xy -1 = r_1 x_1+ r_2 x_2 + \cdots + r_n x_n$. This is where I no more knew what to do.   Your advise will be appreciated. What is the symbol on the supply voltage that looks like a shaded-in capacitor? I am looking at  (dual low-voltage power amplifier). On the fourth page, there is a sample circuit; right at the V+ input there is a symbol that looks like a capacitor. However, it looks like it is shaded in. What is that? Can my friend and I play minecraft together with different mods? I'm wondering if I could play Minecraft with my friend. A modded Minecraft, only myself with mods and him without mods.  Is it possible? Prove that any finite group $G$ of even order contains an element of order $2.$ Solving $ax \equiv c \pmod b$ efficiently when $a,b$ are not coprime I know how to compute modular multiplicative inverses for co-prime variables $a$ and $b$, but is there an efficient method for computing variable $x$ where $x &lt; b$ and $a$ and $b$ are not co-prime, given variables $a$, $b$ and $c$, as described by the equation below?   $ a x \equiv c \mod b $   For example, given  $ 154x \equiv 14 \mod 182 $, is there an efficient method for computing all the possibilities of $x$, without pure bruteforce?  Please note that I'm not necessarily asking for a direct solution, just a more optimized one.    I do not believe that the Extended Euclidean Algorithm will work here, because $a$ and $b$ are not co-prime.   Edit:  Follow up question, since the first one had a shortcut:  Could the be computed efficiently as well?  $12260x \equiv 24560 \mod 24755$.  $107$ needs to be one of the computed answers. I'm using the following syntax for my code snippets  \begin{minipage}{\textwidth} \begin{lstlisting}[caption=&lt;something&gt;, label=&lt;something&gt;] The REST Endpoint URL     is http://api.flickr.com/services/rest/  To request the flickr.test.echo service,     invoke like this:    http://api.flickr.com/services/rest/       ?method=flickr.test.echo&amp;name=value  By default, REST requests will send a REST response. \end{lstlisting} \end{minipage}   and I would like to have  \begin{code}[&lt;caption&gt;, &lt;label&gt;] ... code ... \end{code}   which would behave exactly the same.   So I tried this thing but it won't compile and I can't spot the problem  \newenvironment{code}[2][]%     {         \minipage{\textwidth}          \lstset{             basicstyle=\ttfamily,             breaklines=true,             captionpos=b,             frame=bottomline,             extendedchars=true         }         \begin{lstlisting}[caption=#1, label=#2]     }     {         \end{lstlisting}         \endminipage     }   Error when running pdflatex  ! Package inputenc Error: Unicode char \u8:�\expandafter not set up for use with LaTeX.  See the inputenc package documentation for explanation. Type  H &lt;return&gt;  for immediate help. How can I convert timestamps in a column to a date? I have a file containing this:  1415602803,LOGIN SUCCESS,AUTH,user2,192.168.203.63,10.146.124.73,59996,22 1415602807,LOGIN SUCCESS,AUTH,user1,172.24.31.10,172.32.1.1,48191,22 1415602811,LOGIN FAILED,AUTH,root,172.24.166.153,10.146.124.73,52506,22 1415602815,LOGIN FAILED,AUTH,user3,192.168.123.55,10.146.32.99,55750,22   I want to convert the timestamp to a date in this format:  2014-11-10 02:00:03,LOGIN SUCCESS,AUTH,user2,192.168.203.63,10.146.124.73,59996,22 2014-11-10 02:00:07,LOGIN SUCCESS,AUTH,user1,172.24.31.10,172.32.1.1,48191,22 2014-11-10 02:00:11,LOGIN FAILED,AUTH,root,172.24.166.153,10.146.124.73,52506,22 2014-11-10 02:00:15,LOGIN FAILED,AUTH,user3,192.168.123.55,10.146.32.99,55750,22   How can I do that?  I know this works: perl -pe 's/(\d+)/localtime($1)/e' (from ) but the output format is Mon Nov 10 02:00:03 2014.  I know this command can convert timestamps into my desired output: date -d@1415602803 +"%F %H:%M:%S", but I couldn't make it work with awk using system("cmd") because of all the quotations and whatnot. How much money do I need to show as proof of support when applying for a UK Standard Visitor visa? Why are there no Pokémon near me? Some of you might insist that it was not a murder, as we know that a rebounding spell had hit Ariana, as shown in .  However, a death in such a well known family would not go uninvestigated, I presume. Were the Dumbledore brothers investigated? How did they get away with their sister suddenly dropping dead?  I'd think that Ministry of Magic has means to recognize a death caused by magical means. That's how we know that Tom Riddle Snr. was killed by Avada Kedavra. So Ariana's failing health might be a poor excuse. How do neutrinos pass through the sun so quickly? If it takes thousands of years for light to escape our sun then how can neutrinos generated in the very center of the sun reach earth in just 8 minutes? Why is their speed so great that they can easily escape the pull of the sun at near light speed?     Solar neutrinos originate from the nuclear fusion powering the Sun and other stars. The details of the operation of the Sun are explained by the Standard Solar Model. In short: when four protons fuse to become one helium nucleus, two of them have to convert into neutrons, and each such conversion releases one electron neutrino.   The Sun sends enormous numbers of neutrinos in all directions. Each second, about 65 billion ($6.5\times 10^{10}$) solar neutrinos pass through every square centimeter on the part of the Earth that faces the Sun.[8] Since neutrinos are insignificantly absorbed by the mass of the Earth, the surface area on the side of the Earth opposite the Sun receives about the same number of neutrinos as the side facing the Sun.   - How to clear the interpreter console? Like most Python developers, I typically keep a console window open with the Python interpreter running to test commands, dir() stuff, help() stuff, etc.  Like any console, after a while the visible backlog of past commands and prints gets to be cluttered, and sometimes confusing when re-running the same command several times.  I'm wondering if, and how, to clear the Python interpreter console.  I've heard about doing a system call and either calling cls on Windows or clear on Linux, but I was hoping there was something I could command the interpreter itself to do.  Note: I'm running on Windows, so Ctrl+L doesn't work.