I'm wondering where on StackExchange I could ask for how other people interpret a specific license agreement and also whether people have rejected to agree to the specific liencese agreement because of certain aspects within it.  It would be very helpful to gain insights from other people's view on the specific service agreement in order to decide whether or not to agree to the license and start using the service.  The specific service I'm interested in is . Their  states in section 3.2 that:     You hereby grant Company an irrevocable, non-exclusive, royalty-free, transferable license, with rights to sublicense, to use, reproduce, modify, display, perform and create derivative works of the Applications, the Content and the Brand Features and Marks for the sole purpose of allowing the Company to provide the Company Software and the Services to You.   For me it is very important that the content I would put into my Firebase database would remain mine and that it would only be used by/accessible to those that I explicitly grant access.  The license agreement says that I would grant Firebase the right to use the content (which is something I do not wish to agree to), but on the other hand it also says that Firebase is only granted to do so for the sole purpose of providing the service to me.  I'm confused by this and would appreciate any sites that I can ask questions about this issue.
Is it appropriate to ask questions about software licenses/licensing on ? Or is the appropriate place  ? Or is there no appropriate site currently and we should suggest such a site on ?
When you die, what contributes to your "Score"? When you die, 3 things happen.    You swear  A message appears in the chat log describing how you died A "You died" screen appears, with the options to quit or respawn, and a "Score".   What contributes to this score? Does the series $\sum\limits_{n=1}^\infty \frac{1}{n^3 \sin^2n}$ converge or diverge? I have this series given by $$\sum\limits_{n=1}^\infty \frac{1}{n^3 \sin^2n}.$$ I know that the terms are all nonnegative. Can I get a subsequence of $\frac{1}{n^3 \sin^2n}$ such that its sum diverges to $+\infty$? Integration of secant $$\begin{align} \int \sec x \, dx  &amp;= \int \cos x \left(  \frac{1}{\cos^2x} \right)  \, dx \\ &amp;= \int \cos x \left(  \frac{1}{1-\sin^2x} \right) \, dx \\ &amp; = \int\cos x\cdot\frac{1}{1-\frac{1-\cos2x}{2}} \, dx \\ &amp;= \int \cos x \cdot\frac{2}{1+\cos2x} \, dx  \end{align}$$  I am stuck in here. Any help to integrate secant? Double rm verification in zsh When I do a rm * in zsh, I get something like this:  2014-06-08 10:14:23 $ rm * zsh: sure you want to delete all the files in /home/assay/assay/log [yn]? y rm: remove regular file `development.log'? y   First zsh asks me if I am sure I want to delete all, and then rm asks for for each specific file.  How can I just have the zsh verification? How do I add Python to the Windows PATH? I want to be able to run Python commands from the Windows CMD. However, if I don't specify Python's full path for each command, I get an error saying "Python is not recognized as an internal or external command, operable program or batch file."  How do I add Python to the Windows PATH permanently? Optimizing a "black box" function: Linear Regression or Bayesian Optimization... what's the difference? Goal: I have a function $f(x,y)=z$ (two variables for illustration only) which I know almost nothing about--it has a compact domain which I can determine, it is non-negative, and bounded above.  My goal is to find the maximum value $f(x,y)$ takes on its domain.  I can query the function and I know the values at a few points: $f(x_1, y_1)=z_1, f(x_2, y_2)=z_2,..., f(x_n, y_n)=z_n$.  Optimization via Linear Regression:  I have used linear regression (and related methods like the lasso) to model functions like this in the past; this is the method that I am very comfortable with.  Typically, I might try to find a polynomial (of degree $k$) which relatively accurately models the data. The end result would be to say that:   $$f(x,y)\approx \beta_1 + \beta_2 x + \beta_3 y + \beta_4 x^2 + \beta_5 xy + \beta_6 y^2 + ... + \beta_{m}y^{k}.$$  Determining the coefficients is done by solving the .  The "best degree" for the polynomial might be determined using $k$-fold cross validation.  Once the "best" polynomial has been determined, one can choose any of a number of methods to optimize it (Newton's method, gradient descent, hill climbing, etc).  Then, if all goes well, the optimal value on the polynomial corresponds to an optimal value of $f(x,y)$.  Bayesian Optimization:  Recently, I was describing this technique (linear regression) to a colleague who asked: "What is the difference between that and Bayesian Optimization?"  I've been attempting to answer this question for the last couple days, and so far I don't have anything really conclusive.  After reading , trying to read  and getting stuck reading  I think I understand the following about BO:   Start with a prior (a guess as to what family of functions the black box belongs to... or at least some family of functions which you believe might be able to describe $f$ well).  It looks using a  as a prior is popular. Specify whatever is needed to build your prior (for GP this is a covariance function). As you go along, you maintain two evolving functions, a "mean" function $m(x,y)$ and a "confidence interval" function $c(x,y)$.  Basically, you can predict the value at any point by evaluating $m(x,y)$ and you are confident that $f(x,y)\in [m(x,y)-c(x,y), m(x,y)+c(x,y)]$. Bayesian optimization provides a systematic way of updating/exploiting the model by alternatively selecting points where the confidence interval is wide (you are very uncertain about the value) or at optimal points on the model $m(x,y)$.   My Question: Is it fair/correct to say that the major difference between Bayesian Optimization and simply optimizing the linear regression model is that Bayesian Optimization provides the systematic way of sampling with the goal of optimizing the model and reducing uncertainty whereas the linear regression model ignores the idea of uncertainty and doesn't explicitly provide a means of updating the model?  Said another way, is the linear regression model an example of what might be a "mean" function $m(x,y)$ in Bayesian Optimization?  If I stick with linear regression, specify how to compute the uncertainty, and provide a means of updating/improving the model (exploit/explore) am I just doing Bayesian Optimization (without calling it that)?  Background: My background is in pure mathematics (graph theory) but my new job has me working with a lot of data (so I'm self learning statistics).  With that in mind, my statistics vocabulary is somewhat limited (so I appreciate answers that either avoid technical terminology or briefly explain any technical terminology used)--for example, Monday was the first time I heard/read the word "prior" used in a stats sense and I'm still not 100% sure I understand that correctly. Which gears combinations shouldn't be used? Is there any general rule or recommendation to avoid usage of certain gears combinations (for 2xN and 3xN gears systems)? Do they differ for mtb and road bikes?  I know that it's recommended not to use biggest front chainring with big chainrings on cassette (and opposite) because parts will wear faster and I will loose a bit of pedaling efficiency, but I'm not sure, if I should avoid 2 or 3, or even more biggest (smallest in opposite case) chainrings on cassette. Ubuntu Server VM: copy paste? I've installed Ubuntu Server under Virtualbox just to get a nice little shell. I've also installed the VirtualBox "Guest Additions" and set "Shared Clipboard: Bidirectional".  I still can't seem to get any copy-paste working. Am I missing something here?    I've installed  which gives mouse support in server mode (no X), and allows copy-paste using the mouse, but still the VirtualBox integration doesn't work. What's the meaning "them" here? I've confused about the word "them" in the middle of the sentence:     They know all about them   Westovers in Idaho.   Could you please tell me what the meaning of "them" here is?     Does it mean "they know about the oils which are made by Westovers in Idaho"?   The full text is here:      Dad had always said he wanted to build a room the size of a cruise ship   but I’d never thought he’d have the money. I looked to Mother for an   explanation but it was Dad who answered. The business was a roaring   success, he explained. Essential oils were popular, and Mother had the best   on the market. “Our oils are so good,” he said, “we’ve started eating into the   profits of the large corporate producers. They know all about them   Westovers in Idaho.”   Educated by Tara Westover I am building a regression model and I need to calculate the below to check for correlations   Correlation between 2 Multi level categorical variables Correlation between a Multi level categorical variable and continuous variable  VIF(variance inflation factor) for a Multi level categorical variables   I believe its wrong to use Pearson correlation coefficient for the above scenarios because Pearson only works for 2 continuous variables.   Please answer the below questions   Which correlation coefficient works best for the above cases ?  VIF calculation only works for continuous data so what is the alternative?  What are the assumptions I need to check before I use the correlation coefficient you suggest?  How to implement them in SAS &amp; R? Convergence of the series $\sum a_n$ implies the convergence of $\sum \frac{\sqrt a_n}{n}$, if $a_n>0$ I need help to solve following problem from Rudin's Mathematical analysis book:    Convergence of the series $\sum a_n$  implies the convergence of $\sum \dfrac{\sqrt {a_n}}{n}$, if $a_n&gt;0$  I tried to construct a suitable convergence sequence $b_n$ such that $\sum b_n$ converges and $a_n \leq b_n$ but, I am not able to find such sequence $b_n$ .  Thanks for the help and sugestions. messenger()->addMessage not working after a $form_state->setResponse In the submitForm of a custom form, I have this:    switch ($form_state-&gt;getValue('suscribe')) {   case 0:     $iStatus = 1;     break;   case 1:     $iStatus = 3;     $sFileName = 'sites/default/files/_private/bulletins/' . $form_state-&gt;getValue('adherent')[1] . ".pdf";     $response = new BinaryFileResponse($sFileName);     $response-&gt;setContentDisposition(       ResponseHeaderBag::DISPOSITION_ATTACHMENT,       'bulletin.pdf'     );     $form_state-&gt;setResponse($response);     break; }  $storage = \Drupal::entityTypeManager()-&gt;getStorage('member'); $id = $form_state-&gt;getValue('adherent')[0]; $entity = $storage-&gt;load($id); $entity-&gt;status = $iStatus; $entity-&gt;save();  \Drupal::messenger()-&gt;addMessage($this-&gt;t('Your wish has been recorded.'));   suscribe is a Yes/No radio button. $form_state-&gt;setResponse($response); triggers the automatic download of a pdf document.    The message (Your wish...) is correctly displayed in case 0. In case 1, the message shows only if I refresh the page (or go to another page). How can I have the message displayed without doing another action after submitting the form in case 1?    By the way, database is correctly updated in both cases. I'm using Drupal 8.6.10. I have been thinking about ways of teaching electronics and I'm wondering if the following is true...  For starters, when we talk about voltage as energy per unit charge, is this energy manifest simply as the kinetic energy of the electron?  So, all other things being equal, will the electrons coming out of a 4 volt battery will have twice the velocity of electrons coming out of a 1 volt battery because of ${1 \over 2}mv^2$?  This would seem to imply that the voltage drop across different parts of the circuit is essentially a comparison of the electron speeds at those points.  Furthermore doesn't this imply that the electrons are nearly halted by the time they reach the positive terminal of the battery? This makes intuitive sense to me, it seems pedagogically sound, and it provides an explanation for how electrons "know" to give up their energy across the circuit -- electrostatic repulsion communicates later resistances to earlier parts of the circuit.  How much of the above is correct? The one things that makes me suspicious is that, in this picture, electron density at the positive terminal of the battery is very high, and repulsive forces would prohibit this. On the other hand, if the Joules per Coulomb are not coming from kinetic energy, then what? The field? But wouldn't that just dissipate as light?  Something is wrong but I don't know what. Can I downgrade to Mavericks after installing Yosemite (beta/developer preview)? I have installed the developer preview for Yosemite.  Huge mistake. Everything in my workspace is broken.  I don't have any sort of backup image. I was wondering if I could re-download Mavericks and run the installer - would that effectively downgrade me back to Mavericks? We have a fairly big MS SQL 2008R2 database that resides on a SSD drive. The drive itself only has ~110Gb of space, and the database files are the only files on the drive.  The database is in "Simple" recovery mode, and only has two files, .MDF and .LDF.   The disk is now nearly full: the MDF is currently 109Gb in size. However, SSMS tells me there's nearly 18Gb of "Space Available" (in the 'General' properties page), and if I go through the motions of Shrinking the file it also tells me there's 18Gb of space free. SSMS also tells me the database size is around 132Gb, which surprises me - that wouldn't fit on the drive!  From what I've read, shrink is a really bad idea. However, I'm starting to see replication errors (could not allocate space for object). We've previously tried shrinking the database, but within a few hours the file was back to it's original size.  How should we proceed - given there's apparently 18Gb of free space, should SQL automatically use that free space? Or is it as simple as: we really need more disk space? What does the '!' really do when it's added to an ex command (:wq! | :w! | :q! )? I understand that it means force to do something.  When doing $ vim -R file I enter in read-only mode, but this works as preventive mode only   -R  Readonly mode.  The 'readonly' option will be set for all the     files being edited.  You can still edit the buffer, but will     be prevented from accidentally overwriting a file.  If you     forgot that you are in View mode and did make some changes,     you can overwrite a file by adding an exclamation mark to     the Ex command, as in ":w!".  The 'readonly' option can be     reset with ":set noro" (see the options chapter, |options|).     Subsequent edits will not be done in readonly mode.  Calling     the executable "view" has the same effect as the -R argument.     The 'updatecount' option will be set to 10000, meaning that     the swap file will not be updated automatically very often.   But what I can't get yet is why it makes the instruction to skip permissions even if the file's owner is root user, besides it also change owner &amp; group. Proof of A ⊆ C and B ⊆ C ⇔ A ∪ B ⊆ C I know that this is valid because by thinking about it, you can see it's true, but I'm just not sure how I would go about actually proving it mathematically. I've kind of tried proof by contradiction, since that's what I use most of the time, but it doesn't seem to work.    In my mind, A ∪ B ⊆ C kind of just implies that A ⊆ C and B ⊆ C. Do extension fields always belong to a bigger field? Let $F$ be a field, $E_1$ and $E_2$ are two distinct extension fields of $F$. Is it the case that we can always somehow find a field $G$ that contains both $E_1$ and $E_2$? In other words, could extensions of fields have different 'direction's such that they are incompatible?  Edit: I began to think about this problem while reading a proof. $F$ is a field. $a$ and $b$ are algebraic over $F$. $p(x)$ and $q(x)$ are two polynomials in $F[x]$ of minimum degree that respectively make $a$ and $b$ a zero. The proof claims that there is an extension $K$ of $F$ such that all distinct zeros of $p(x)$ and $q(x)$ lie in $K$. For a single polynomial, I know this kind of field exists because of the existence of splitting field, why it is true for two polynomials? valueOf() vs. toString() in Javascript Systemd is really slow in comparison to upstart I have been using Ubuntu for a long time now, this is what happened when I use:  Systemd: It performs really bad using systemd: it uses 95% of the CPU all the time and the PC gets really hot. Also it takes a really long time to boot (about 1.5 min, and sometimes it does not boot at all as it has a black screen at boot.)  Upstart: When I tried the upstart options at boot, it performs as expected, booted in seconds, and it was awesome as it should be.  Laptop:   AMD A8 Radeon SSD   Questions:   Why does upstart perform better than systemd? How can I debug systemd? Should I switch to upstart? If yes, how do I do it?