I looked around and seems like its not possible according to another post. As a workaround, i'm using a bunch of white images to act as the background color change. Any way to change the black color itself or a better workaround?
I would like to render an animation as a series of .png images with transparent backgrounds for use in a video. Is this possible?
What is the difference between data mining, statistics, machine learning and AI?  Would it be accurate to say that they are 4 fields attempting to solve very similar problems but with different approaches? What exactly do they have in common and where do they differ? If there is some kind of hierarchy between them, what would it be?  Similar questions have been asked previously but I still don't get it: Circle Rolling on Ellipse I've gotten interested in describing a circle rolling on an ellipse; specifically, the curve traced out by a point on the circumference of the circle. I want a symbolic solution to the general case, radius $r$, axes $a$ and $b$. I've written nine polynomial equations in terms of various angles and lengths.  Exactly what "solution" means is subject to debate.  Let $(u,v)$ be the point on the circle. Similar to the cycloid, I would like an equation for $u$ in terms of a "natural" angle in the problem.  Similarly, an equation for $v$.  Perhaps it is necessary to have a differential equation, so maybe $du/dt$, $u$, and $t$, where $t$ is an angle in the problem.  I would have thought this was known, but I can't find it anywhere. How to approximate the student-t CDF at a point without the hypergeometric function? Is there a way to closely approximate the CDF of a student-t distribution at a point $x$ without involving the hypergeometric function? For example, by using a series expansion, or expressing the CDF in terms of simpler functions?  The t-distribution can   $$t = \frac{X\sqrt{n}}{Y}$$  where $X$ is normally distributed with mean 0 and variance $\sigma^2$; $\frac{Y^2}{\sigma^2}$ has a chi-squared distribution. Maybe this expression can help simplify the t CDF?  I am trying to write an algorithm to compute the student-t CDF for any real number, so using the hypergeometric function will be extremely difficult. I am also trying to avoid integrating the PDF to get the CDF. Chinese Passport Holder Transit in South Korea A Chinese passport holder with a US visa has a flight scheduled from Beijing to Los Angeles in mid-November.  This person wants to go to South Korea for a 3 day conference; the conference is one week prior to the PEK-LAX flight.  If this person buys a round-trip ticket from China to Korea, will the transit visa be sufficient? Or will they need a regular visa?    Extra info:  What if the original ticket were modified to make it ICN-PEK-LAX?  . It says "Holding a confirmed onward flight ticket for departure within 30 days." Would a return ticket to China than a flight to LAX a week later be sufficiently "onward"? Blurry Text On Model After Render Logistic regression in R resulted in perfect separation (Hauck-Donner phenomenon). Now what? I'm trying to predict a binary outcome using 50 continuous explanatory variables (the range of most of the variables is $-\infty$ to $\infty$). My data set has almost 24,000 rows. When I run glm in R, I get:  Warning messages:   1: glm.fit: algorithm did not converge   2: glm.fit: fitted probabilities numerically 0 or 1 occurred    I've read the other responses that suggest perfect separation might be occurring, but I'm confident that isn't the case in my data (though quasi-complete separation could exist; how can I test to see if that's the case?). If I remove some variables, the "did not converge" error might go away. But that's not always what happens.  I tried using the same variables in a bayesglm function and got the same errors.  What steps would you take to figure out exactly what's going on here? How do you figure out which variables are causing the problems? Is there a way to open a raster that is stored in ESRI V10.0 Geodatabase in QGIS V2.4?    I can open the vector layer, but there does not seems to be a way to open a raster. Is it possible to explicitly tell Stack Overflow the language of the code block you are including? Possible Duplicates:             Stack Overflow awesomely detects what language a code block is and syntax highlights it accordingly. But sometimes it fails. Is it possible to explicitly tell it what the language is?  php:  if ( force_ssl_admin() &amp;&amp; !is_ssl() ) {     if ( 0 === strpos($_SERVER['REQUEST_URI'], 'http') ) {         wp_redirect(preg_replace('|^http://|', 'https://', $_SERVER['REQUEST_URI']));         exit();     } else {         wp_redirect('https://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI']);         exit();     } }   ruby:  def destroy   @payment = Payment.find(params[:id])   @payment.destroy    redirect_to :back end   yaml (FAIL)  foo: this is foo! bar: this is bar! id: 5 What is the structure in "as best you can"? I instinctively translate it "as best as you can", however this makes no sense.  What is the real structure behind this phrase?  I'll include an  to illustrate the historical presence of this phrase:    Whatever the structure is, I'm guessing that it has something to do with 19th century grammar. I would like to treat a user as a non-gender noun and refer to it with the gender-neutral pronoun, it. E.g.,     The user defines two variables, x and y. It then multiplies each variable by a prime number.    However, on  I found this:      The word "it", however, has an extremely impersonal connotation, even offensive, in common usage and is rarely used in English to refer to an unspecified human being or person of unknown gender. This is because the word "it" connotes that the person being specified is inferior to a person or is an object.   Is to appropriate to refer to a person of unknown sex as it?  Should I rephrase my sentence as follows:     The user defines two variables, x and y. The user then multiplies each variable by a prime number. Syntax of bash alias definition I'm using Cygwin, and have installed all the developer packages as well as most if not all of the other packages. When I provide an alias for gcc, I get the error  -bash: alias: gcc: not found   What could I be doing wrong?  I am typing the following command into the terminal:  alias gcc "gcc -ansi -Wall -g -O0 -Wwrite-strings -Wshadow -pedantic-errors -fstack-protector-all"   FYI, this alias works on other systems. I've always heard this reasoning, and it makes obvious sense, but how do you actually show it for some arbitrary product? Would it be something like this?  $$(a(b(cd)))e=((ab)(cd))e=(((ab)c)d)e=abcde?$$  Do you just say that the grouping of the parentheses now corresponds to just multiplying straight through? Thanks. Questions with ignored tags still visible in iOS app I have set to ignore [php] tag and chose to hide questions in preferences:        But I still see questions tagged [php] in the iOS app.         Seems the app can't distinguish options for ignored tags.   App Version: 1.6.5.3 Device: iPad Air 2 (Wi-Fi) OS Version: Version 10.3.1 (Build 14E304) fsck error on boot: /dev/sda6: UNEXPECTED INCONSISTENCY; RUN fsck MANUALLY Print lines between (and including) two patterns I want to start grepping from the lines that has CK at the end of line and stop grepping when the line has D at the end. I tried grep "$CK" "$D" file..txt, but it didn't work.  Input:  kkkkkkkkkkk    jjjjjjjjjjjjjjjjjj   gggggggggggg/CK   JHGHHHHHHHH    HJKHKKLKLLL    JNBHBHJKJJLKKL   JLKKKLLKJLKJ/D   GGGGGGGGGGGGGG   GGGGGGGGGGGGGG   The desired output:  gggggggggggg/CK   JHGHHHHHHHH    HJKHKKLKLLL    JNBHBHJKJJLKKL   JLKKKLLKJLKJ/D I need to use a different version of circuitikz. How can I do that? Is it true that $\mathbb{R}$ and $\mathbb{R}^2$ are isomorphic as abelian groups? I think the answer is yes.   Sketch of the proof Consider $\mathbb{R}$ as a vector space over $\mathbb{Q}$. Let $\{e_\lambda:\lambda\in\Lambda\}\subset\mathbb{R}$ be its Hamel basis. Then $\{(e_{\lambda_1},e_{\lambda_2}):\lambda_1,\lambda_2\in\Lambda\}\subset\mathbb{R}^2$ is a Hamel basis of $\mathbb{R}^2$. Consider set theoretic bijection $i:\Lambda\to\Lambda\times\Lambda$ define map $\varphi:\mathbb{R}\to\mathbb{R}^2$ by its action on element of Hamel basis of $\mathbb{R}$ by equality $\varphi(e_\lambda)=(e_{i(\lambda)_1},e_{i(\lambda)_2})$. This is an isomorphism between $\mathbb{Q}$-vector spaces $\mathbb{R}$ and $\mathbb{R}^2$.  Question Could you tell me is this proof correct, and if it is not, where is the mistake?  EDIT: Thanks to GAJO we found that this proof is wrong. The correct one basis is  $$ \{(e_\lambda,0):\lambda\in \Lambda\}\cup\{(0,e_\lambda):\lambda\in\Lambda\} $$ So we had to look at bijections of the form $i:\Lambda\to\Lambda\coprod\Lambda$ and the desired linear operator is defined by equalities $\varphi(e_\lambda)=(e_{i(\lambda)},0)$ if $i(\lambda)$ lies in the first copy $\Lambda$ and $\varphi(e_\lambda)=(0,e_{i(\lambda)})$ otherwise. It seems that OTP encryption is unbreakable. I have read some articles (Wikipedia, Blogpost, etc.), but I could not find any information about how they are used.  If I wanted to create a messenger service, how would I distribute the OTP keys? Both the sender and the receiver need this key before the message is sent, right?   And how do I make sure no one else gets these keys? Android - Read Only File System IOException Black screen after installation of Ubuntu 18.04 I did a fresh complete install of Ubuntu 18.04 on my ASUS M32CD desktop.   Everything during install went fine. At the end it said it was complete complete, and would reboot. Popped the disc out. Rebooted itself back into bios so I changed it back from CD boot as primary to HD.  When it booted up for Ubuntu screen and then everything went black and can’t do anything now! Ugh. Help