When clicking a column in the reputation graph on my profile, the previous days' details are displayed, even if no changes happened on that day. The tooltip also shows the wrong date. In the example below (taken on StackOverflow), clicking on "Aug 14" shows data for Aug 13 while the tooltip at Aug 13 shows August 12.    Note that even if my question is a duplicate of , it was closed and fixed, but the issue seems to have reappeared and as such I'm posting it again.  Browser I'm using is Opera 30.0.1835.125 on Windows 10
So when we view reputation, there is graph view. However, it seems to be off by a day. Here's what I mean:   I'm sure 70 + 20 + 15 is not 15. Its 105, which is what we see below:   And 40 + 10 is NOT 105, unless you did  :)     Anyways 40 + 10 is 50:   So yeah. Did you do what that post on codegolf says? Devs better fix that :)
In class we've seen that $a$ (the weights) must satisfy $$X^T (y-Xa) =0$$  Here $X$ is a $(n\times d)$ matrix (so we have $n$ samples in $\mathbb R^d$)  let's denote the residuals $r = y-Xa$. In our class notes, it is written that     The normal equations require the residuals to be orthogonal to each of the columns of $X$.   Why?     Therefore, the solution of the linear regression is a projection of $y$ onto the subspace spanned by $v_1 , \ldots , v_d$ (the columns of $X$)   Can you please explain this? If I root my Android phone, will I lose all of my data? PostgreSQL multi-column unique constraint and NULL values I have a table like the following:  create table my_table (     id   int8 not null,     id_A int8 not null,     id_B int8 not null,     id_C int8 null,     constraint pk_my_table primary key (id),     constraint u_constrainte unique (id_A, id_B, id_C) );   And I want (id_A, id_B, id_C) to be distinct in any situation. So the following two inserts must result in an error:  INSERT INTO my_table VALUES (1, 1, 2, NULL); INSERT INTO my_table VALUES (2, 1, 2, NULL);   But it doesn't behave as expected because according to the documentation, two NULL values are not compared to each other, so both inserts pass without error.  How can I guarantee my unique constraint even if id_C can be NULL in this case? Actually, the real question is: can I guarantee this kind of uniqueness in "pure sql" or do I have to implement it on a higher level (java in my case)? Difference between a Structure and a Union Is there any good example to give the difference between a struct and a union? Basically I know that struct uses all the memory of its member and union uses the largest members memory space. Is there any other OS level difference? SQL function as default parameter value? I tried changing a default parameter value with this:  ALTER PROCEDURE [dbo].[my_sp] @currentDate datetime = GETDATE()   and all the SQL pre-compiler gave me was this error:     Msg 102, Level 15, State 1, Procedure my_sp, Line 8 Incorrect syntax near '('.   I have already created the procedure. (I'm not sure if that's relevant.) I was using a null default value and checking for that later, but that doesn't seem proper. Can I do this in one line?   Update: I was going off of :      [ = default ] Is a default value for the parameter. If a default value is defined, the function can be executed without specifying a value for that parameter.            Note:     Default parameter values can be specified for CLR functions except for the varchar(max) and varbinary(max) data types.         When a parameter of the function has a default value, the keyword DEFAULT must be specified when the function is called to retrieve the default value. This behavior is different from using parameters with default values in stored procedures in which omitting the parameter also implies the default value.   Am I reading this wrong?  Many thanks. How to measure the component value on a PCB? How can I vertically center a "div" element for all browsers using CSS? I'm looking for a class in java that has key-value association, but without using hashes.  Here is what I'm currently doing:   Add values to a Hashtable. Get an iterator for the Hashtable.entrySet(). Iterate through all values and:   Get a Map.Entry for the iterator. Create an object of type Module (a custom class) based on the value. Add the class to a JPanel.  Show the panel.   The problem with this is that I do not have control over the order that I get the values back, so I cannot display the values in the a given order (without hard-coding the order).  I would use an ArrayList or Vector for this, but later in the code I need to grab the Module object for a given Key, which I can't do with an ArrayList or Vector.  Does anyone know of a free/open-source Java class that will do this, or a way to get values out of a Hashtable based on when they were added?  Thanks! How do I keep both the background and foreground in the image in focus at the same time? How do you have both the background and foreground in the image in focus at the same time?  Last week I was attempting a shot where I had the back of a hat in focus and in the distance you could see a mountain. I wanted both in focus, but could either focus on the mountain or the hat. I ended up taking the in-focus shots of both and merging them in Photoshop. While that isn't difficult I would prefer to shoot the shot as accurate as possible. From what I have read aperture is important in the depth of field but what are the techniques for keeping both the background and foreground in focus?  I am using a Nikon D5100 with a 18-55mm f/3.5-5.6 (standard kit lens) and a 55-200mm  f/4.5-5.6.    almost answers my question, but I am a bit confused. Can someone explain this a bit differently? Thanks! Probability that a quadratic polynomial with random coefficients has real roots The following is a homework question for which I am asking guidance.     Let $A$, $B$, $C$ be independent random variables uniformly distributed between $(0,1)$. What is the probability that the polynomial $Ax^2 + Bx + C$ has real roots?   That means I need $P(B^2 -4AC \geq 0$). I've tried calling $X=B^2 -4AC$ and finding $1-F_X(0)$, where $F$ is the cumulative distribution function.  I have two problems with this approach. First, I'm having trouble determining the product of two uniform random variables. We haven't been taught anything like this in class, and couldn't find anything like it on Sheldon Ross' Introduction to Probability Models.  Second, this strategy just seems wrong, because it involves so many steps and subjects we haven't seen in class. Even if I calculate the product of $A$ and $C$, I'll still have to square $B$, multiply $AC$ by four and then subtract those results. It's too much for a homework question. I'm hoping there might be an easier way. Unique constraint that allows empty values in MySQL In the book I'm reading at the moment () it says that if you don't declare a default constructor for a class, the compiler supplies one for you, which "zeroes out each data member". I've experimented with this, and I'm not seeing any zeroing -out behaviour. I also can't find anything that mentions this on Google. Is this just an error or a quirk of a specific compiler? Spider-Man is the one franchise that is on course to a third reboot in a span of 15 years.   My question is what was the reason for these numerous reboots of Spider-Man which pretty much follow the same origin story for the Marvel superhero.  Has the comic creator or studio ever spoken out about the reasoning behind the same? What are the differences between executing shell scripts using "source file.sh", "./file.sh", "sh file.sh", ". ./file.sh"? Error: 'else' without 'if' Do fontsize environments exist? Without any doubt there are fontsize switches in the form of control sequences (described  for instance.) But, from time to time I ran into code examples where environment versions of those were used, e.g. \begin{small}...\end{small}. After testing those successfully I began to incorporate them into my TeX vocabulary.  A few days ago @GonzaloMedina commented on one of my answers that those environments do not exists and constructions relying on them work by pure coincidence. Then I tried to find out more about those ominous environments. Ominous because they don't seem to be somehow documentated. (The only thing I found that tried to explain them in a somehow systematical manner was some Wikibooks resource.)  Are these environments real or not? How does Dijkstra's Algorithm and A-Star compare? I am able to backup my app's data from the root/data/data/you.package.name directory by just moving it to SD card manually. however, when i reverse the process,                                                                                                               AKA paste the data back to simulate a restore, the app just force closes, i have tried it with a bunch of apps and noticed the same reaction. Where am i wrong? Can the milky way actually be photographed ? I know the image is manipulated, and is probably a composite, but how do you capture such contrast in the milky way? Is an equitorially mounted scope required? Any advice or pointers are welcome, thanks.  I'm heading out towards much less light polluted areas middle of next week and I want to try some nighttime sky captures with my 7D.  Additional info: I just found  on wikipedia that says: 54s, tripod mounted 5D, 16mm lens, f/2.8, ISO800. What else do I need to be aware of? My 7D is only an APS-C and the widest lens I have is 19mm. I'm thinking that might not be wide enough to capture an interesting shot? I own a 2016 Macbook (with the USB-C charging) - at the time and in response to all of the reports of poor cables and poor chargers, I bought a meter so I could see what the throughput of my cables/chargers was. However, having run some tests I'm now not sure what to consider normal / what is harmless to the battery.   For all tests I used an original Apple C-C cable - though was able to replicate with two third party cables I own.  I have the original Apple block charging at 14.3 V / 1.99 A and a third party block that charges the same.  Another third party block which advertises USB PD and 3 A is currently charging at 20 V / 1.43 A  I've done some research online but I can't find any articles that indicate what a normal USB PD output is relative to the devices that connect to it and would appreciate any guidance / assistance.   TL;DR: Have Apple charger which charges at one voltage/amperage. Bought several others advertised at PD which are higher voltage, lower amperage. Not sure what is 'safe', or 'fast', or does least overall damage to battery.