Why Pandas Dataframe (and Python) have a strange float-precision decimal value assignment which impacts rounding?
Is floating point math broken?
Do we have different badges in different SE sites Inverse elements in the absence of identities/associativity. Moving here does not mean moving to a new city or something like that. I am talking about the people that just can't stay at one place. It is impossible for them to sit put at one place and relax. How do I install drivers for Realtek RTL8812BU? Anything I should keep in mind before I start mixing and matching between D&D 3.5e and Pathfinder? Anything I should keep in mind before I start mixing and matching between D&amp;D 3.5e and Pathfinder?  Off the top of my head, the biggest difference is feats every 2/3 levels. Would it affect balance if I picked every 3 levels instead of 2? I think PF options are still pretty solid regardless... $\mathbb Z[i]/ \langle 1+2i \rangle \cong \mathbb Z_5$ I am trying to prove that $\mathbb Z[i]/ \langle 1+2i \rangle$ is isomorphic to  $\mathbb  Z_5$.   The only thing that came to my mind was trying to apply the first isomorphism theorem using an appropiate function. If I consider the euclidean function $N: Z[i] \setminus \{0 \}  \to  \mathbb N$ defined as $N(a+bi)=a^2+b^2$, then I can express any element $z$ in $\mathbb Z[i]$ as $z=(1+2i)q+r$ with $N(r)=1,2,3,4$ or $r=0$.   If I define $f:\mathbb Z[i] \to \mathbb  Z_5$ as $f(x=(1+2i)q_x+r_x)=\overline{r_x}$, then it is clear that $f(x)=0$ if and only if $x \in  \langle 1+2i \rangle$. The problem with this function is that it doesn't satisfy $f(x+y)=f(x)+f(y)$ and it is not surjective for if $r_x=f(x)=3 (5)$, then if $r_x=a+bi$, we have $a^2+b^2=3$, which is absurd.  I don't know what else to do, any suggestions would be appreciated. How do you deserialize json properties that are reserved words in apex? The AC adapter supplied with my laptop is designed to accept voltage in the range of 100-240VAC at 50-60Hz, but the AC cable that plugs into the adapter unit itself is only rated to 125VAC 7.5A 2.5A.  I know the adapter can accept 220V power, but is it safe to use this cable with the AC adapter to plug into a 220V socket?  Edit: The part in question is a 90W HP Smart AC Adapter.  The laptop does not cause the AC adapter to draw more than about 80 watts from the socket (as measured with a Kill A Watt meter).  Edit 2: The amperage rating of the cable as marked on the attached label is 2.5A, not 7.5A. RegEx for Javascript to allow only alphanumeric Stack Overflow has successfully borrowed at least one XBox feature (Achievements).  I'd like to see another feature borrowed as well. Let's say I'm playing Halo online and another player is being a bigot.  I have the option to add him to a list of ignored users.  After doing that, all the racist things he says will never be heard through my headphones anymore. Now, on Stack Overflow, I'd like the ability to add a user to a list of ignored users.  This would hide all of that user's comments, and maybe his questions and answers as well (not sure if hiding questions/answers is necessary). This serves multiple purposes:  It would make it easy for users to avoid other users' flamebait. It would give users a more appropriate response to flamebait. The ability to start flame wars would be reduced, since fewer users would see those comments. Users would now have an incentive to be more diplomatic, as there is now a negative consequence to the behavior (the silent treatment). Administrators could review which users are the most often ignored, which would be a strong indication that someone should be  or even locked out of their account. Administrators wouldn't have to spend as much time dealing with complaints about abusive users, since users would have a better way to respond.    makes a good point in a comment to an answer, that I thought should get more visibility:  I had a problem, reported it and got the response &quot;not bad enough to do anything about, sorry&quot;. Which is kind of true, because the only options available to the mods are the nuclear one (penalty box) and the zero-effect one (do nothing). We need a middle ground option where abuse can be handled for you without also being handled for everyone. How to use mysql JOIN without ON condition? Responsive Web Design - what should happen when the mobile device is rotated? Currently, the standard behaviour for viewing web pages on a mobile is that:   If viewed in portrait the text is smaller because the width of the device is small and the whole page width needs to fit into view. If viewed in landscape the view 'zooms in' as the width is now wider so that the text is larger and more readable, but with less content on screen as a result.   So, this brings a dilemma. When creating a responsive website what should happen on device rotation? (Not on initial page load, I am referring to what should happen once the site is loaded and you decide to then rotate the screen)   When rotated from portrait to landscape should you:   a) Re-detect the device widths and map the contents according to the new dimensions (thereby retaining the same font / images sizes as when viewing portrait). b) Keep the same dimensions and on rotation just bring the content to fit the window (thereby zooming in the content to make it more readable for viewers if the portrait orientation text is too small).          &ndash; Wireframes created with   Bear in mind that with a traditional web-page viewed in the mobile you have the option of pinch-to-zoom the text, so if it's too small you can zoom in. With a responsive site this isn't an option because the site will fit the dimensions so there is nothing to zoom into.  (I guess there is a third option too - use responsive fonts so that the font sizes change according to the screen width. But that's probably a different question altogether). How do you beta test an iphone app? How can you beta test an iPhone app?  I can get it on my own device, and anyone that gives me a device, I can run it on theirs, but is there a way to do a limited release via the app store for beta testing?  Related: Also, see  on getting your app onto phones without using the App Store. Keep box-shadow direction consistent while rotating Often I see code blocks pasted into questions with no formatting, or terrible formatting.  It's sometimes quite a chore to fix these: you have to either manually space out each line, or paste the code into an IDE, format it there, and paste it back.  Could we have a button/function where you could highlight a code block, and it would turn this:  foreach (var i in stuff) { if (i==1) { Whatever(); } }   into this:  foreach (var i in stuff) {   if (i==1) {     Whatever();   } }   I realise the function would have to work differently based on the language in the code block. Perhaps  it could use the same rules as the prettify code.  Also, it wouldn't be a big deal if it gets the language wrong and breaks the code, since you can always just ctrl+z. When I open this ssh tunnel:  ssh -nXNT -p 22 localhost -L 0.0.0.0:8984:remote:8983   I get this error when trying to access the HTTP server running on localhost:8984:  channel 1: open failed: administratively prohibited: open failed   What does this error mean, and on which machine can you fix the problem? $g^\frac{p-1}{2} \equiv -1 \ (mod \ p)$ Let $p$ be an odd prime, and let $g$ be a primitive root modulo $p$. Prove that $g^\frac{p-1}{2} \equiv -1 \ (mod \ p)$.  I've seen this solution on the math stack exchange but most of the solutions use quadratic reciprocity. Unfortunately, I skipped that section because it seemed very hard, but the proof that  $g^\frac{p-1}{2} \equiv -1 \ (mod \ p)$ seems easy with it.  Is there another way to solve this This question is proposed in the chapter of Finite Abelian Groups.  DEF:In elementary number theory, an integer $g$ is called a primitive root for the modulus $n$ if $\mathbb{Z}_n^\times$ is a cyclic group and $[g]_n$, is a generator for $\mathbb{Z}_n^\times$. Foobar2000-like music player? Flash Player works on Firefox, but not on Chromium? I want to play online games, and other online stuff that requires Flash Player on the internet. Flash Player works just fine under Firefox, but in Chromium I just get a blank page. I don't know what is the exact problem or know to fix it. I bought a Minecraft account for my little brother for Christmas, and I'd like to play with him on my server every now and then. If I log in while he's on, however, it kicks him off since we have the same username. Is there any way to change my username so that I can play with him, or anything I can do so that we can both play together using this account on my server?  I'm open to anything that could let us play, whether it be username changes, server property changes, etc.