So I'm brushing up on my vanilla Javascript, specifically for animation, and I came across a tutorial with the following code:  function sprite(options){          var spr = {},             frameIndex = 0,             tickCount = 0,             ticksPerFrame = options.ticksPerFrame || 0,             numberOfFrames = options.numberOfFrames || 1;          spr.context = options.context;         spr.width = options.width;         spr.height = options.height;         spr.image = options.image;         spr.loop = options.loop;          spr.render = function(){             console.log("render");             //console.log("height: ", spr.height);             //console.log("width: ", spr.width);             //console.log("context: ", spr.context);             //console.log("image: ", spr.image);              // Clear Canvas             spr.context.clearRect(0, 0, spr.width, spr.height);              // Draw animation             spr.context.drawImage(                 spr.image,                 frameIndex * spr.width / numberOfFrames,                 0,                 spr.width / numberOfFrames,                 spr.height,                 0,                 0,                 spr.width / numberOfFrames,                 spr.height             );         };          spr.update = function(){             tickCount += 1;              if (tickCount &gt; ticksPerFrame){                 tickCount = 0;                  if (frameIndex &lt; numberOfFrames - 1){                     frameIndex += 1;                 } else if (spr.loop) {                     frameIndex = 0;                 }             }         };          return spr;     }   I understand all of the logic and everything, but how are    frameIndex tickCount ticksPerFrame numberOfFrames   accessible from the render() and update() methods after spr has been returned? As far as I can tell, they're local functions to the sprite function and shouldn't be accessible after instantiation.
How would you explain JavaScript closures to someone with a knowledge of the concepts they consist of (for example functions, variables and the like), but does not understand closures themselves?  I have seen  given on Wikipedia, but unfortunately it did not help.
Plotting a Continuous signal Prove that: $(f(x))^{2} + (f'(x))^{2} \leqslant \max(a,b)$ where $(a,b) \in \mathbb{R}^2$ Let $f\in C^2(\mathbb{R},\mathbb{R})$.   Assume there exist  $(a,b) \in \mathbb{R}^2$ such that  $\forall x \in \mathbb{R}, (f(x))^{2} \leqslant a$ and $(f'(x))^{2} + (f''(x))^{2} \leqslant b$.   Prove that: $$(f(x))^{2} + (f'(x))^{2} \leqslant \max(a,b)$$ for all $x \in \mathbb{R}$.   I tried to use taylor lagrange with the integral form of the remainder but I did not succeed.  Ì really don't know how to tackle  the problem.   Any suggestion, Hint (or Answer) will be very helpful,  Thank you in advance, Strange set notation (a set as a power of 2)? I am not very well versed on set theory or syntax, but I thought I knew the basics.  However, in a book about databases I am reading now, the author uses $2^x$ to signify "a set of $x$."  For example, $2^{\text{dogs}}$ is a set of $\text {dogs}$, etc.    The author never really explained this or why he does it, I just picked up the meaning from context.    I am not sure why the exponent operator is used, nor am I sure what the number $2$ has to do with it.  The sets being represented are NOT powers of $2$ (in size)... they come in all sizes.  Is this a valid notation?  I have not seen it anywhere before... rsync over ssh "error in protocol data stream" (code 12). ssh works I tried:  rsync -v -v -e 'ssh -p YY' ./testfile me@XXXXX:/home   Error Message  opening connection using: ssh -p YY -l me 146.6.84.206 rsync -&gt;-server -vvve.s . /home  [sender] make_file(testfile,*,0) send_file_list done send_files starting server_recv(2) starting pid=17537 rsync: connection unexpectedly closed (9 bytes received so far) [sender] rsync error: error in rsync protocol data stream (code 12) at io.c(600)[sender=3.0.6] _exit_cleanup(code=12, file=io.c, line=600): about to call exit(12)   This works fine:  ssh -p YY me@XXXXX   Which suggests to me the problem is neither that sshd is not running nor that port YY is firewalled. I have checked anyway.  What other problems could there be?  EDIT: The problem seems to have been "self resolving." I could not replicate the following day. I started my local computer up. Perhaps notably I had a different IP address than last time. And now rsync magically works. I'd appreciate guesses as to what it could have been in light of it going away. Refreshing Formula Fields Dynamically (without save) I have an "invoice" custom object which has a couple of summarising formula fields in. I also have a complicated and dynamic visualforce page for building the invoice objects.  As the user is completing this form, different areas are dynamically updated to show "latest" values. This is all fine where I am copying data about or performing bespoke lookups and maths, but - in what is really the simplest case - a formula field, I can find no way to get the value to update, without performing some weird cyclic save + reload of the whole object.  This is inappropriate for a couple of reasons (the object should not be saved until the invoice is complete + accepted) and the other option I have found online is to spoof the value by duplicating my formula field maths into the custom controller and re-executing them there - also unacceptable from a code/logic location/duplication perspective.  Is there anyway to "force" an object/page to recalculate it's formula fields, either through standard or extended controllers? The residue at $\infty$ I am stuck on the following problem :      $\,\,\,\,$*Problem*$\quad$The residue of an entire function at $\infty$ is $0$.      Solution: True. This follows from the definition of the residue at $\infty$ together with the Cauchy-Goursat Theorem. Another way to see this is to take the Taylor expansion for $f$ at $0$ $\displaystyle f(z)=\sum_{n=0}^\infty a_nz^n$ and replace $z$ with $1/z$ to get the Laurent expansion for $f(1/z)$ at $0$: $\displaystyle f(z)=\sum_{n=-\infty}^0a_{-n}z^n.$ Then we have that the residue at $\infty$ is given by the negative coefficient of the $1/z$ term of    $$ \dfrac1{z^2}f\left(\dfrac1z\right)=\sum_{n=-\infty}^{-2}a_{-n-2}z^n, $$   which is clearly $0$.   I am having trouble to understand the last few lines (in italic) in the given solution. Can someone give lucid explanation? Thanks and regards to all. How do I get the UI thread's Dispatcher? Why there is much interest in the study of $\operatorname{Gal}\left(\overline{\mathbb Q}/\mathbb Q\right)$? Integral representation $B_T^3$ I have to find a $F_t$ such that $B_T^3=E[B_T^3]+\int_0^T F_t dB_t$. I have shown by ito formula that $B_T^3=\int_0^T 3 B_s^2 dB_s+\int_0^T 3 B_s ds$. Could you please help me? Ralink RT3290 bluetooth adapter does not work, but wifi works perfectly. QGIS save postgis table error : no result buffer I've a polygon layer on PostGIS, and when I try to add featureS using QGIS it gets error when I save the edit.   Here is the error notification "no result buffer".     I found a similar case here : . But it doesn't give me the answer to solve it. Any ideas ? How can I change my default text editor from gedit to Emacs? How do I create a WiFi hotspot sharing wireless internet connection (single adapter)? Delete all files except files with the extension pdf in a directory FM Transmitter oscillation problem I've been trying to get this simple FM transmitter to work over the past few days and I could use some help in a few areas.      First iteration was on a breadboard with all parts included.  The exception being I didn't have a 0.1uH coil handy but I had another coil rated at 0.7uH (using my LCR meter).  I also didn't have a C4 value of 4.7pF but I had a 10pF value.  I figured I could just tune it later.  I hooked a scope up to it and got no oscillation.  I tried connecting the probe to the gate and the collector separately and together.  Still no oscillation.  Second iteration.  I removed the audio component of the circuit.  Essentially everything to the left of C2.  I had gotten that working no problem anyway so I figured I would concentrate on the oscillator.  This time I tried different values for the inductor ranging from 20uH to 1mH and different fixed values for the variable cap (10pf, 20pf, 30pf).  These were all ceramic caps. No love.  Third iteration. I tested the transistor to make sure that wasn't the issue.  Seems fine.  PN2222A variety. (Also tried 2N3904 and BC547). I then modeled this up on a piece of perf board.  I even found a SMD inductor of 0.1uH so now I thought I would be good.  Tested all the pieces on the meter before installation. Still nothing. I'm not seeing anything on the spectrum analyzer either.  Questions:   Do you think my benchtop power supply is causing a problem?  All the various versions of this type of FM transmitter circuit on YouTube and the Internet all seem to use a battery.  Any chance the 60Hz main power is messing with things?  I've put .1uF and higher caps on the power rails. I have a 200Mhz SIGLENT SDS1202X-E scope.  I've built and tested other oscillators up to a few MHz before with no issues.  Any thoughts on that being the issue?  I would expect to see something on the scope right? Any chance the probe is dampening the oscillations?     I know there are a lot better FM transmitter circuits out there I was just experimenting with this (and others like it) and couldn't get any to work. How to test apex classes with Pagereference? I'm struggling to test a class with pagereference. Following is the class...  public with sharing class redirectOrderPartner{  public String currentRecordId {get;set;} public orders__c orderId {get;set;}  public redirectOrderPartner(ApexPages.StandardController controller) {      }     Public Pagereference go(){      currentRecordId  = ApexPages.CurrentPage().getparameters().get('orderid');      system.debug('---currentRecordId  ---'+currentRecordId  );     orderId = [select id from orders__c where name =: currentRecordId limit 1];      system.debug('---orderid---'+orderId);      PageReference pageRef = new PageReference('/apex/OrderTrackingClass?id='+orderId.id);     pageRef.setRedirect(true);     return pageRef;    }   }   Following is what I tried....    @isTest  public class redirectOrderPartner_TEST  {             static testMethod void Test(){            Account acc = new Account(Name='ABC Corp.');           insert acc;            orders__c tempOrder = new orders__c(name = '0001234567', account__c = acc.id );           insert tempOrder;            Test.startTest();            PageReference pageRef = Page.redirectOrderPartner;           Test.setCurrentPage(pageRef);            ApexPages.Standardcontroller sc = new ApexPages.Standardcontroller(tempOrder);           ApexPages.currentPage().getParameters().put('Id',tempOrder.name);           PW_redirectOrderPartner ec = new redirectOrderPartner(sc);           ec.go();                                   Test.stopTest();       }   } I get the following error message on testing..     System.QueryException: List has no rows for assignment to SObject   What am I missing? Thanks i m using ubuntu 10.10. please tell me how to type in hindi fonts in open office word. please help Rails lists have .first and .second – is there a .hundredth or .sixty_nineth ? How to increase JAVA Heap Size? Preventing console window from closing on Visual Studio C/C++ Console application