How to make low poly water with foam effect?
Animating Dynamic Paint with noise texture
Foreign key constraints failures Given the following tables:  CREATE TABLE `longdescs` (   `comment_id` int(11) NOT NULL AUTO_INCREMENT,   `bug_id` mediumint(9) NOT NULL,   `who` mediumint(9) NOT NULL,   `bug_when` datetime NOT NULL,   `work_time` decimal(7,2) NOT NULL DEFAULT '0.00',   `thetext` mediumtext NOT NULL,   `isprivate` tinyint(4) NOT NULL DEFAULT '0',   `already_wrapped` tinyint(4) NOT NULL DEFAULT '0',   `type` smallint(6) NOT NULL DEFAULT '0',   `extra_data` varchar(255) DEFAULT NULL,   PRIMARY KEY (`comment_id`),   KEY `longdescs_bug_id_idx` (`bug_id`),   KEY `longdescs_who_idx` (`who`,`bug_id`),   KEY `longdescs_bug_when_idx` (`bug_when`),   KEY `comment_id` (`comment_id`),   CONSTRAINT `fk_longdescs_bug_id_bugs_bug_id` FOREIGN KEY (`bug_id`) REFERENCES `bugs` (`bug_id`) ON DELETE CASCADE ON UPDATE CASCADE,   CONSTRAINT `fk_longdescs_who_profiles_userid` FOREIGN KEY (`who`) REFERENCES `profiles` (`userid`) ON UPDATE CASCADE ) ENGINE=InnoDB AUTO_INCREMENT=82727 DEFAULT CHARSET=utf8  CREATE TABLE `trace` (   `id` mediumint(9) NOT NULL AUTO_INCREMENT,   `comment_id` mediumint(9) NOT NULL,   `type` varchar(255) NOT NULL,   `short_hash` char(22) DEFAULT NULL,   `stack_hash` char(22) DEFAULT NULL,   `trace_text` mediumtext NOT NULL,   `quality` double NOT NULL,   PRIMARY KEY (`id`),   UNIQUE KEY `trace_comment_id_idx` (`comment_id`),   KEY `trace_short_hash_idx` (`short_hash`),   KEY `trace_stack_hash_idx` (`stack_hash`) ) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8  ALTER TABLE trace ADD CONSTRAINT `fk_trace_comment_id_longdescs_comment_id` FOREIGN KEY (`comment_id`) REFERENCES `longdescs`(`comment_id`) ON UPDATE CASCADE ON DELETE CASCADE; ERROR 1005 (HY000): Can't create table 'bugs4.#sql-4bb_6f1d' (errno: 150)   MariaDB [bugs4]> show warnings;  | Level  | Code | Message | | Warning |  150 | Create table 'bugs4/#sql-4bb_6f1d' with foreign key     constraint failed. There is no index in the referenced table where the referenced columns appear as the first columns.  | | Error   | 1005 | Can't create table 'bugs4.#sql-4bb_6f1d' (errno: 150)                                                                                                                       |   Any idea why I get that error? FYI I looked it up and it appears that it was a bug but not anymore. In a family with two children, what are the chances, if one of the children is a girl, that both children are girls? In a family with two children, what are the chances, if one of the children is a girl, that both children are girls?  I just dipped into a book, The Drunkard's Walk - How Randomness Rules Our Lives, by Leonard Mlodinow, Vintage Books, 2008. On p.107 Mlodinow says the chances are 1 in 3.   It seems obvious to me that the chances are 1 in 2. Am I correct? Is this not exactly analogous to having a bowl with an infinite number of marbles, half black and half red? Without looking I draw out a black marble. The probability of the second marble I draw being black is 1/2. How do I run executable scripts in Nautilus? When I double-click on a script in Nautilus to run it, the script just opens in my text editor with no option to run it. Using Nautilus, how do I run executable text files and/or scripts? How do I remap certain keys or devices? using $$ in a post causes strange number series to appear I want to create an effect on a character where their skin and clothing are effected by two different light sources. The clothing should only reflect a bright bounce light, but have the skin should not be affected by this light source.    In the example image I have two objects a cube, a sphere and three emission  lights . I want the two white lights to hit both objects, and I need the purple light to hit and reflect off of the sphere, but ignore the cube entirely (no reflections).  Someone suggested to composite the layers together, it works... but this is very impractical and cumbersome because it forces the background to be transparent and it will be a pain to try and layer together a more complex scene, especially if its animated which is what I want this effect for.  I know you can have objects ignore shadows and all kinds of other things so im hoping someone knows how to get an object to ignore light with a few settings. Deputy badge after a reputation of 3000 Mysterious! Beamer itemize has no bullets after adding a few packages this is my first time using beamer.  I copied a template from the sharelatex page on Beamer  Which works, and \begin{itemize} shows bullets     But after adding a few more packages that I need, all the bullets are gone!    What is going on and how can I fix this?  \documentclass{beamer}  \usepackage[utf8]{inputenc}    \usepackage{amsmath}  \usepackage{amsthm}     %Theorem Environment  \usepackage{amssymb}  \usepackage{multirow}  \usepackage{cancel}  \usepackage{amsfonts}  \usepackage{graphicx}  \usepackage{subfigure}  \usepackage{upgreek}     \usepackage{mathtools}  \usepackage{thmtools}  \usepackage{enumitem}       %Information to be included in the title page: \title{Sample title} \author{Anonymous} \institute{ShareLaTeX} \date{2014}  \begin{document}    \frame{\titlepage}    \begin{frame}  \frametitle{Sample frame title}  \begin{itemize} \item  This is a text in first frame.  \item This is a text in first frame. \item This is a text in first frame.  \end{itemize}  \end{frame}  \end{document} How do I set up new users with skel i have on my server a settings i use for all my users. every time i create a new user i have to copy all the settings over and over.  for example:   .vimrc. .profile .bashrc firefox homepage to our intranet evolution settings (server and username) etc...   i saw skel can do it, is there a easy way to setup a user with my settings when i adduser?  thanks Sharepoint 2010 - Deploy webpart as Feature scope = web I want to create and deploy a web part as web-scoped feature.  In Visual Studio 2010, when I make the feature scope=web, I cannot add the webpart to that feature as I am able to do when scope=site. Drawing a constant randomly distorted circle I am trying to draw a special and contradictive plot : A circle with random distortions which have to remain constant regardless of how many times I build the document.  An example of what I am trying to achieve can be seen below    This figure was produced with the following code  \documentclass{standalone} \usepackage{tikz}    \usetikzlibrary{decorations.pathmorphing}   \begin{document}     \begin{tikzpicture}         % axes         \draw[ultra thin] (-2.5, 0) -- (2.5, 0);         \draw[ultra thin] (0, -2.5) -- (0, 2.5);         % undistorted sphere         \draw[ultra thin, dashed] (0, 0) circle (2.25cm);         \draw[ultra thin, dashed, -&gt;] (0:0) -- (125:2.25);         \node at (-1, 1) {$R$};         % distrorted sphere         \draw[very thick] plot[domain=0:350,smooth cycle ] (\x:2+rnd*0.5);         \draw[very thick, -&gt;] (0:0) -- (45:2.1);         \draw[ultra thin, -&gt;] (1, 0) arc (0:45:1);         \node at (1.2, 0.4) {$\theta$};         \node at (0.7, 1.25) {$R(\theta)$};     \end{tikzpicture} \end{document}   The problem with the code is that whenever I make a change to it and rebuild the document, the "distorted" circle will have a different shape, since I am using the rnd function. The reason I would like to have a constant-random shape is because I would like to denote its radius at an angle θ, therefore it has to touch the outline of the circle.  Any idea on how to achieve such a thing? According to , POST is used to create a resource:  The POST method is used to request that the origin server accept the entity enclosed in the request as a new subordinate of the resource identified by the Request-URI in the Request-Line.  According to , PUT is used to create or replace a resource:  The PUT method requests that the enclosed entity be stored under the supplied Request-URI. If the Request-URI refers to an already existing resource, the enclosed entity SHOULD be considered as a modified version of the one residing on the origin server. If the Request-URI does not point to an existing resource, and that URI is capable of being defined as a new resource by the requesting user agent, the origin server can create the resource with that URI.  So which HTTP method should be used to create a resource? Or should both be supported? Novel(s) based on humanity fleeing from Earth and regressing to a pre-industrial state on a Colony so as to escape detection Shortly before his death, my father spoke to me about a series of novels that he had just finished reading which had a fascinating concept.  However I soon forgot the title(s) and author and I've been absolutely desperate to find out what they were.  The premise (as I understood) was that humanity had expanded out from the solar system into the local star systems before coming into contact with an incredibly aggressive species which was focused on wiping out the entire species.  Earth and her colonies were lost as remnants of the species fled.  Eventually it was decided by the military leadership to set up a colony in order to rebuild the human race.  However, in order for this colony to escape detection and to keep humanity from going back out into space and thus potentially running into this hostile alien race again, a series of satellites were set up around the planet chosen that would lock onto and destroy any form of technology (and usually the surrounding city) that went beyond pre-industrial standards.    One of the series protagonist is a long living android who possesses the consciousness of a human who was present at the original founding of the colony (and who seems shielded from detection) which observes as civilization is repeatedly regrown and torn down again and who attempts to try and reverse humanities self imposed lot in life.      From what I understood this was a series of novels, but I could be wrong. I've been trying to find this for years on my own with only a rough plot line as a guide and it's gotten me nowhere. How do I pass variables and data from PHP to JavaScript? How to make /sbin/shutdown, /sbin/reboot etc. require sudo again in 16.04? For whatever reason, we do no longer need to be root (or using sudo) to run /sbin/shutdown, /sbin/reboot etc.  This seems to be because those executables are now symlinks to /bin/systemctl which handles everything as normal user.  However, what if I want shutdown and reboot to require root authentication again? How can I achieve this? My specific question is with the ASUS M3N78-VM motherboard that my home server uses. I currently have 4x2GB installed for a total of 8GB but I was hoping to upgrade to say 16GB (4x4GB). The official specifications of that motherboard says it only supports up to 8GB but it was released back when only 2GB sticks were available. What, if any, would prevent it from working with 4GB sticks now that 4GB sticks are available?  My general question is with motherboards in general... what would prevent a motherboard from working with bigger sticks if its all just the same type (DDR2 for example and same speeds) of memory? Proving $\frac{1}{\sqrt{x}}\ge \frac{2}{x+1}$ for $x> 0$ Prove: $$\frac{1}{\sqrt{x}}\ge \frac{2}{x+1}, \quad\forall x&gt;0$$  Yeah, pretty much it. I've tried all manner of rearranging and just can't seem to get it. Thanks. I need to show that $$ \int\limits_1^{\infty}x^\alpha\sin(x^\beta)dx $$ converges if and only if $\alpha + 1 &lt; \beta$. I used substitution and integration to get $$ \lim\limits_{t\to\infty}\int\limits_1^tx^\alpha\sin(x^\beta)dx \overset{u = x^\beta}{\underset{du = \beta x^{\beta-1}}{=} }\lim\limits_{t\to\infty}\left(\frac{1}{\beta}\int\limits_1^{t^\beta}u^{\frac{\alpha + 1 - \beta}{\beta}}\sin{u}du\right) $$ If $\alpha + 1 -\beta &lt; 0$, then we have a product if a function with bounded anti-derivative and a differentiable decreasing function which tend to 0, and from Dirichlet's criterion, the integral converges.   For the converse, I used integration by parts $$  = \frac{1}{\beta}\lim\limits_{t\to\infty}\left(\left.-u^{\frac{\alpha + 1-\beta}{\beta}}\cos{u}\right|_1^{t^\beta} + \frac{\alpha+1-\beta}{\beta}\int\limits_1^{t^\beta}u^{\frac{\alpha + 1-2\beta}{\beta}}\cos{u}du\right) $$ For $\alpha + 1 -\beta\geq 0$, I get that the first term indeed diverges, but this is not enough to show total divergence. How can one show it? How do you prevent a user from posting data multiple times on a website Alternative to Photoshop or Paint.NET I have been moving toward Ubuntu from a long time Windows development background. The one program I cannot seem to do without is a graphic editor. I have seen recommendations for programs, but they turn out to be directed at children or tailored to working with personal photographs.  I am looking for something more for programming tasks like analysing colors, resizing, creating web graphics, etc. I have used Photoshop in the past and more recently have mostly used Paint.net for Windows.  Is there a program for Ubuntu that covers this area?