double not (!!) vs type coercion in JavaScript
When to use the double not (!!) operator in JavaScript
Processor: PIC18F66K22 Compiler:  C18 (XC8 is fine also)   I've just made (and succesfully tested) code to measure the voltage on AN4 analog pin.  Now I want to try something else, not quite sure if it's theoretically possible.  My test-board has a PIC processor, with VDD,AVVD connected to a supply (ranging from 0(if the battery is empty/disconnected) to 4,2(full battery).  Can I use ADC to measure the VDD(-in) of my board?  Why not?:   It's not an ANx pin, not sure how to make the ADC measure it? (Channel?) If the voltage on VDD(-in) drops, will my ADC reference voltage also drop? (So when my PIC only gets 3,3V the ADC will still say it's 100% (as the max Voltage on the chip, also the reference is 3,3V).   Why/what do you ask?:   Can I just measure Channel 30 (VDDCORE)? Could I set my Vref to Vdd and measure a precision voltage reference with the A/D converter. (Not sure how) Or I could add a wire from VDD-in to an ANx pin? Will Internal VREF+ (4.096V) stay 4+V when the VDD-in is around 3,4V? Is there some kind of transformator that makes it so? Internal VREF+ (4.096V) is a bit lower than the max of the battery (4,2V), does this mean I can damage the ADC? Or just that the result will be max when the battery is full. (4,2V out of 4,096V)     Please mind that my knowledge of Electronics is "low". I've learnt way more about the software part in my education, but I'd like to know more about (Embedded) Electronics as it's a crucial part in Embedded Engineering. (It's sad how my school doesn't see this.) I have two desktops (one of which I'm using as a server), my main machine has a weaker i5 cpu, my server has a stronger i7 cpu. On my main machine I am experiencing stutters because the CPU often runs at full load under regular use (strangely, I also use upwards of 10GB of RAM, no joke... The heaviest program I'm running is google chrome).  I was wondering if there was any possible way to share a cpu from one machine over network to another machine as an emulated processor, which could be used by the client machine in a similar sort of fashion as virtual machines use or "borrow" their host's cpu.  This way I could offload work onto the server's cpu when the main cpu is under full load to prevent annoyances like stutter, and possibly combine both of them for more intense tasks (like decryption, compilation, archiving or other multithreaded stuff)  Does this sort of software exist, or has anyone at least tried to make it? If not, is it feasible?  (This sort of program would also ideally be able to offload data onto the server's RAM for faster processing, since the now common gigabit connections get to have nearly the same speeds as a standard HDD this doesn't sound far fetched either)  To reiterate, what I am primarily looking for is the ability to offload work from a system's main cpu when it is under too much load and forwarding it to another computer's cpu over network. SQL Coalesce in WHERE clause I'm trying to implement optional parameters in a stored procedure that I have but I am running into a problem. Here's a simplified query to illustrate the issue:  SET ANSI_NULLS OFF  DECLARE @MiddleName VARCHAR(20); SET @MiddleName = NULL;  SELECT * FROM [Customer] WHERE [LastName] = 'Torres' AND [MiddleName] = COALESCE(@MiddleName, [MiddleName])   When I run this query I need to get one row back because one Torres has NULL in the [MiddleName] column. But the query returns zero rows. Using IFNULL() produces the same result. From researching COALESCE, I was under the impression that NULL would be returned if all expressions are NULL. As I am not a SQL expert I assume that I am missing something, but what is it.....  Thanks in advance for any help. How should we handle downvote retaliation? I have a situation where I'm trying to figure out what the right thing to do is on SO.    I see a question.  I answer the question.  I see there are a couple other answers.  One answers the question well, though with less explanation than my answer.  The other answer seems both wrong and irrelevant to the question (doesn't answer the question at all).  I comment to that effect.  The "wrong" part is edited out, but the author of the answer doesn't respond to how their answer actually answers the question.  In fact, they seem offended that I don't "get" it.  After giving them several chances to explain how their answer is relevant to the question and seeing their attitude, I decide to downvote their answer as I don't see how it addresses the question at all and the author won't explain.  They retaliate and downvote my answer and admit in their comments that their downvote of my answer has nothing to do with the content of my answer and only because they don't like me disputing their answer.  Did I do the right thing by downvoting their answer?  Do I just have to live with their downvote retaliation?  Anything I should have done differently?  I also have no way of knowing this for sure, but the next question I answered was upvoted, then downvoted so perhaps this same person is stalking my answers and downvoting other answers of mine too with no comment.  As long as this doesn't continue, I'm not losing sleep over a couple downvotes, but I do wonder if I should have done anything differently.  Followup Later After I Posted This Question: After thinking about it for a little while, the person who disagreed with me decided to delete their post.  So, eventually the message did get through to them.  I don't know if they rescinded their downvote or not (or if they even could). continuity, discontinuity derivative and relation to being derivative but its partials are not continuous is $$f(x) =\begin{cases} x^2\sin(\frac{1}{x}) \mbox{ for } x\neq 0 \\ 0  \mbox{ for } x= 0\end{cases}$$ a continuous function specially at point x=0?  And why being derivable its derivative is not continuous at x=0 since  $$f`(x) =\begin{cases} 2x\sin\frac{1}{x}-\cos\frac{1}{x} \mbox{ for } x\neq 0 \\ 0  \mbox{ for } x= 0\end{cases}$$?  I suspect this as to do with being derivable a function f $\mathbb{R}^n\rightarrow\mathbb{R}^m$ that don't imply its partial derivatives are continuous .this I don't get it so far.however partials derivatives if continuous is derivable.  Can you provide me a more general case than just one variable where f is derivable but its partials are not continuous? So I currently have this issue where my Epson WF-3620DWF can't find the blue and yellow cartridges. (They are official epson ones) and I have a full black cartridge in there. How do I force my printer to ONLY print in black and ignore the cartridge(s) not recognised error? How can I access and process nested objects, arrays or JSON? VMware won't work after Ubuntu Upgrade I upgraded to Ubuntu 15.10 and now if I want to open VMware Player it doesn't do anything. I also uninstalled and installed it again, still nothing.  What can I do? Prove any orthogonal 2-by-2 can be written in one of these forms.... I'd like to prove that any orthogonal $2 \times 2$ matrix can be written   $$\bigg(\begin{matrix}    \cos x &amp; -\sin x  \\     \sin x &amp; \cos x   \end{matrix}\bigg) \hspace{1.0em} \text{or} \hspace{1.0em} \bigg(\begin{matrix}    \cos x &amp; \sin x \\    \sin x &amp; -\cos x \end{matrix}\bigg)$$  for $0 \le x &lt; 2\pi$.  I have no idea how to do this. I feel like this is something I've missed and is really straightforward but I can't find it in my book... Is a +1/+1 counter I get from, say Unleash or Undying different than +1/+1 from something like  or ? If $A = \tan6^{\circ} \tan42^{\circ},~~B = \cot 66^{\circ} \cot78^{\circ}$ find the relation between $A$ and $B$ My trigonometric problem is:     If $A = \tan6^{\circ} \tan42^{\circ}$ B = cot$66^{\circ} \cot78^{\circ}$ find the relation between $A$ and $B$.    Working :   $$B = \cot 66^{\circ} \cot78^{\circ} = 1- \frac{\tan24^{\circ}+\tan18^{\circ}}{\tan42^{\circ}}$$  $$A= \tan6^{\circ} \tan42^{\circ} = 1- \frac{\tan6^{\circ} +\tan42^{\circ}}{\tan48^{\circ}}$$  but it seems  this is the wrong way of doing this...please suggest. Thanks! How to print results in SQLcmd window I use bash on both my Mac and as my cygwin shell. Overall, I'm quite pleased with it.  My one complaint however is that its TAB completion isn't as good as Windows Command Line TAB completion.   For example, if there are two files with the same prefix, then bash just beeps at me when I try to TAB complete. If I keep nailing TAB, then it will eventually show me a list of potential files.  I definately prefer how Windows will cycle through potential files right on the command line.   Is there a way to get bash to operate similar to Windows Command Line in this regard?  If there isn't (I do not want to switch shells), am I missing something about TAB completion in bash? Is there a more efficient way to use it? I found the question  Regarding the number of answers votes and also according to my personal taste I like to capitalize titles. But what exactly are titles? Only the single main book title? What about other smaller semantic parts? Chapter headings, sub-chapter, ... Difference between Ubuntu and Linux Mint Can someone please tell me the differences between Ubuntu and Linux Mint ?   I thought they were almost the same thing until I downloaded Ubuntu 13.10 versions of softwares for my Linux mint 16 system, and half of them didn't work. (I did that as those are the links I got when I searched for Linux mint versions) These androids show up day in suburban USA and start offering all their services for free - they are much better than the robot helpers that cost money - the protagonist is a salesman of the latter.   Soon, the 'helpers' are everywhere, and human beings effectively cannot do anything without these things keeping people 'safe'. Humans become infantilized and controlled.   Eventually it's discovered that one man created them, and he's been kept prisoner by them to prevent for his own safety.   This seems remarkably similar to the conclusion of the I, Robot movie. Principal component analysis "backwards": how much variance of the data is explained by a given linear combination of the variables? I have carried out a principal components analysis of six variables $A$, $B$, $C$, $D$, $E$ and $F$. If I understand correctly, unrotated PC1 tells me what linear combination of these variables describes/explains the most variance in the data and PC2 tells me what linear combination of these variables describes the next most variance in the data and so on.   I'm just curious -- is there any way of doing this "backwards"? Let's say I choose some linear combination of these variables -- e.g. $A+2B+5C$, could I work out how much variance in the data this describes? HTML and CSS is not working? Grid System in LaTeX Uniform distribution on the surface of unit sphere