List of algorithms?
How to create my own list of things
Linear transformations map lines to lines I need help with this question:  Let $T$ be a linear map from $\mathbb{R}^n \to \mathbb{R}^m$, and let $L$ be a line in $\mathbb{R}^n$. Show that $T(L)$ is also a line (is it not enough to just consider lines in the plane). Check if wp-login is current page How can I check if the current page is wp-login.php or wp-signup.php ?  Are there more elegant solutions than using $_SERVER['REQUEST_URI'] ? How come gas molecules don't settle down? If the earth's gravity exerts a net downward gravitational force on all air molecules, how come the molecules don't eventually lose their momentum and all settle down? How is the atmosphere is still miles thick after billions of years? I'm designing this animal-type creature, and want to add a transparent .png image to its face with the face features (object has a subsurf). On the left is the image with the features, on the right is the part of the object where I want it to be.    I tried to import the image as a plane, but matching the shape of the plane with the face didn't work, and the lines of the face left shadows on the head, and could be seen as a different object from some angles (although it's the closest I've gotten yet). It looked like this:    So , I tried selecting the faces of the head that the features should go over, and create a new material for it. Unfortunately, since the .png is transparent, the result produced was this:    (where it's impossible to tell the transparency from a black background default color, and where I wouldn't know where to start to adjust size and position).  I also tried UV mapping, but then the whole object became black with the features repeated all over.   Is it something I have to go into Nodes for? I'm kind of stuck here. Creating a new material and applying it is simple, but applying a material that is an image is a bit more complex it seems... Ideally, I would reproduce the same technique for the adhesive bandage on its arm (seen on the right of image 1). Why can "find" not be used in PowerShell? What does find.exe find objectionable about the parameters when it is used in a PowerShell console shell?  These commands work as expected in a cmd.exe shell:  PS C:\Windows\System32\WindowsPowerShell\v1.0&gt; find /i "System.Diagnostics.Process" *.ps1xml FIND: Parameter format not correct PS C:\Windows\System32\WindowsPowerShell\v1.0&gt; find /i "System.Diagnostics.Process" *.ps1xml FIND: Parameter format not correct PS C:\Windows\System32\WindowsPowerShell\v1.0&gt; C:\Windows\System32\find.exe /i "System.Diagnostics.Process" *.ps1xml FIND: Parameter format not correct PS C:\Windows\System32\WindowsPowerShell\v1.0&gt; C:\Windows\System32\find.exe /i "System.Diagnostics.Process" .\DotNetTypes.format.ps1xml FIND: Parameter format not correct Modern electronics industry has developed very efficient LEDs with nice and fancy colors (“true green” , “cyan”, and “blue”) based in InGaN technology, or similar. Some of these LEDs are specified as having forward voltages of 3.2 to 4.2 V. Here are examples of such LEDs, , or surface-mount .  But the usual MCUs are powered from 3.3 V supply, and the GPIO output is usually at 3.1-3.2 V, which seems to be barely enough to drive these LEDs . How can I use these LEDs as indicators of some signal statuses, or power rail status? Do I need a series resistor R1 here?    If yes, how do I choose its value?  DISCLAIMER: This "question-answer" comes as elaboration of the original question , to address the particular use case of LEDs as logic state indicators. Difference between pts and tty $11$ out of $36$? I got this by writing down the number of possible outcomes ($36$) and then counting how many of the pairs had a $6$ in them: $(1,6)$, $(2,6)$, $(3,6)$, $(4,6)$, $(5,6)$, $(6,6)$, $(6,5)$, $(6,4)$, $(6,3)$, $(6,2)$, $(6,1)$. Is this correct? How do I show that $a^p + b^p > (a + b)^p$ for $a,b>0$ and $0<p<1$? A question on my math homework asks us to show that if $0 &lt; p &lt; 1$ and $a, b &gt; 0$, then $a^p + b^p &gt; (a + b)^p$. I have no idea how to do this, any pointers? Why disable Fast Boot on Windows 8 when having dual booting? Is there a way to simulate a numeric keypad on apple wireless keyboard in OSX? I'm tempted to get an Apple Wireless Keyboard but the lack of a number pad is a concern. I'm interested whether there is some form of software you can use where for example you hold some control keys down and you can use a set of keys like the following as a substitute numeric keypad:   7890 uiop jkl; m ./ Windows 10 Icon Gone Missing TL;DR: The Windows 10 upgrade icon went missing. How do I get it back in order to update my system? I am running Windows 7 SP1.   I woke up this morning... er, noon all excited about Windows 10. I had reserved my copy using the clever little icon in the taskbar a few weeks back, so I thought I would be set to go. I booted my computer and checked the icon to see if it would download the update. It still behaved the same as if Windows 10 wasn't launched yet. I supposed this was normal behaviour. After all, Microsoft can't roll out the update to everyone at once.   Windows Update did want me to install several updates though. I installed KB2952664, KB3064209 and KB3048761. Everything went fine, and I was prompted to restart my system.   After restarting, the icon wasn't there anymore. I tried a lot of solutions including the answers provided by our awesome community on , and the answer provided to  posted on the Microsoft Windows support forums.   How do I get the icon back in order to update my system?  UPDATES:   Installing from the Media Creation Tool does not working with an error "Something Happened" with as description "Something Happened". Both are translated from Dutch.  I tried to install it from the Media Creation Tool using PowerISO to mount the created ISO. It will not accept my product key, even though I am able to verify my Windows installation is already registered and the product key is correct. I looked into the Event Log, and GWX-Ins has a bunch of error messages saying: Error message: GWX Main: App failed to start hresult. After that it says what is roughly translated to English as "Cannot find the element". How to pass a list of columns to data.table where some are predetermined Blog Overflow database error , which is linked from site-specific blogs, says  Error establishing a database connection  I believe this is an error. C# 3.0 auto-properties — useful or not? Note: This was posted when I was starting out C#. With 2014 knowledge, I can truly say that auto-properties are among the best things that ever happened to the C# language.  I am used to create my properties in C# using a private and a public field:  private string title; public string Title {     get { return title;  }     set { title = value;  } }   Now, with  3.0, we got auto-properties:  public string Title { get; set; }   I know this is more a philosophical/subjective questions, but is there any reason to use these auto-properties except from saving five lines of code for each field? My personal gripe is that those properties are hiding stuff from me, and I am not a big fan of black magic.  In fact, the hidden private field does not even show up in the debugger, which is OK given the fact that the get/set functions do nothing. But when I want to actually implement some getter/setter logic, I have to use the private/public pair anyway.  I see the benefit that I save a lot of code (one vs six lines) without losing the ability to change the getter/setter logic later, but then again I can already do that by simply declaring a public field "Public string Title" without the need of the { get; set; } block, thus even saving more code.  So, what am I missing here? Why would anyone actually want to use auto-properties? I installed Ubuntu alongside Windows but I did not disable secure boot as someone told me it could cause problems with boot loader. So when installation finished and I rebooted, the system went straight into Windows. I went to Ubuntu IRC Support and they told me to turn off the secure boot and reinstall Ubuntu. I did that but my system still boot into windows.  This is a picture of partitions on my system:    This is my first Ubuntu install on my new laptop. I followed everdaylinux guide to install it and I used something else option. I've got a few macros that perform floating point lookups and calculations for me and I'm interesting in plotting their results. They're the kind of calculation which requires if/else, so they can't be easily written as a simple math formula for \addplot.  Thanks to a previous question (), I now know to use \pgfmathdeclarefunction, but after trying it I've found that addplot seems to prepend a "0Y" or "1Y" to values before passing them as function arguments. My external macros aren't prepared to handle this extra text, and I'm not sure why it's there.   In the course of testing things out, I've also found that calling a function defined with pgfmathdeclarefunction can also change the positioning of the graph...  \documentclass{article}  \usepackage{xparse}  \usepackage{pgfplots} \pgfplotsset{compat=1.10}  \begin{document}  % Example of a macro which does math outside of pgf     \ExplSyntaxOn     \DeclareExpandableDocumentCommand \doubleMacro { m }%      {%       \fp_eval:n { #1*2 }%Math performed by a package other than pgfplots      }%     \ExplSyntaxOff    %Demo: macro does work in regular text \doubleMacro{1.1}.  % Defining custom pgf functions for plotting      \pgfmathdeclarefunction{mathDoubleMacro}{1}{%         \pgfmathparse{\doubleMacro{#1}} %Calls macro which performs math done by another package     }      \pgfmathdeclarefunction{mathDoublePgf}{1}{%         \pgfmathparse{#1*2} %Uses pgf to do the same thing as an external macro could     }  %Generic plot with function given directly to \addplot \begin{center} \begin{tikzpicture}     \begin{axis}         \addplot[domain=0:1] {2*x};     \end{axis} \end{tikzpicture} \end{center}  %Plot using first macro: complains about 'Unknown fp word Y.' \begin{center} \begin{tikzpicture}     \begin{axis}         %\addplot[domain=0:1] {mathDoubleMacro(x)};%Commented out because it gives problems     \end{axis} \end{tikzpicture} \end{center}  %Plot using second macro: works, but graph is displaced to the right of the expected position \begin{center} \begin{tikzpicture}     \begin{axis}         \addplot[domain=0:1] {mathDoublePgf(x)};     \end{axis} \end{tikzpicture} \end{center}  \end{document}   If I define mathDoubleMacro as calling a non-existent macro, then the errors show which x-values which the addplot is trying to evaluate y at:    0Y0.0e0  1Y4.1666e-2 1Y8.3332e-2 ...  1Y9.9998401e-1   What are these nY's all about, and why does \addplot[domain=0:1] {mathDoublePgf(x)} give a graph with different positioning? How can I balance uniformity of style files against modularity? I'm using Windows/TeXworks/MiKTeX, and I would like to have one style file I can use anywhere in any document in my top-level folder. If I want to add a new command or renew an old one, I'd like that to be available in all documents recursively contained in my top-level folder. I have a very hierarchical structure to my top-level folder. So this would seem to point to having a single file that TeXworks knows about. Could I add a path in Preferences -> Typesetting -> Paths for TeX and related programs? I've tried that, possibly superficially, without any success. Adding the correct folder to the Windows PATH variable doesn't seem to do the trick, either.   On the other hand, suppose I want to send someone a TeX file? It would be nice in such circumstances to be able to have the style file in the same folder as the TeX file. If I do that, how could I ensure that it's always up-to-date? Is there a script available somewhere that could take my master style file and push it down to all pre-existing lower-level locations?   Just to reiterate: I want uniformity of my style files in my very hierarchical folder structure. However, I would also like modularity, in that each folder is self-contained. How can I achieve that?  Also, out of curiosity, since I may acquire a Linux computer soon, how would I do this in, say, *ubuntu with TeXlive? How can I swap Ctrl and Fn keys on a corporate computer? Our computers have been upgraded to HP EliteBook 8570p machines and while they're very nice machines, they are also very large -- so large that the left Ctrl key is too far away, making Ctrl+V really difficult to do with one hand.  I'm sure there are ways to re-map the keys so that their signal is swapped. But add the factor of corporate security, is there still a reasonably simple approach to this?  I'm sure you'd like more information before you can answer -- I'll try to add updates based on comments and answers. I have put a bounty on , however I don't see it appear in the  (also not when I'm not logged in).  Why is this. Aren't all bounty questions supposed to be visible there?