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  • Using Taylor Polynomials Programmatically in Maple

    - by kzh
    I am trying to use a Taylor polynomial programmatically in Maple, but the following does not seem to work... T[6]:=taylor(sin(x),x=Pi/4,6);convert(T[6], polynom, x); f:=proc(x) convert(T[6], polynom, x); end proc; f(1); All of the following also do not work: f:=convert(T[6], polynom); f:=convert(T[6], polynom, x); f:=x->convert(T[6], polynom); f:=x->convert(T[6], polynom, x);. Is there a way of doing this without copying and pasting the output of convert into the definition of f?

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  • Using Taylor Series to Avoid Loss of Precision

    - by Zachary
    I'm trying to use Taylor series to develop a numerically sound algorithm for solving a function. I've been at it for quite a while, but haven't had any luck yet. I'm not sure what I'm doing wrong. The function is f(x)=1 + x - sin(x)/ln(1+x) x~0 Also: why does loss of precision even occur in this function? when x is close to zero, sin(x)/ln(1+x) isn't even close to being the same number as x. I don't see where significance is even being lost. In order to solve this, I believe that I will need to use the Taylor expansions for sin(x) and ln(1+x), which are x - x^3/3! + x^5/5! - x^7/7! + ... and x - x^2/2 + x^3/3 - x^4/4 + ... respectfully. I have attempted to use like denominators to combine the x and sin(x)/ln(1+x) components, and even to combine all three, but nothing seems to work out correctly in the end. Any help is appreciated.

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  • Need help programming with Mclauren series and Taylor series!

    - by user352258
    Ok so here's what i have so far: #include <stdio.h> #include <math.h> //#define PI 3.14159 int factorial(int n){ if(n <= 1) return(1); else return(n * factorial(n-1)); } void McLaurin(float pi){ int factorial(int); float x = 42*pi/180; int i, val=0, sign; for(i=1, sign=-1; i<11; i+=2){ sign *= -1; // alternate sign of cos(0) which is 1 val += (sign*(pow(x, i)) / factorial(i)); } printf("\nMcLaurin of 42 = %d\n", val); } void Taylor(float pi){ int factorial(int); float x; int i; float val=0.00, sign; float a = pi/3; printf("Enter x in degrees:\n"); scanf("%f", &x); x=x*pi/180.0; printf("%f",x); for(i=0, sign=-1.0; i<2; i++){ if(i%2==1) sign *= -1.0; // alternate sign of cos(0) which is 1 printf("%f",sign); if(i%2==1) val += (sign*sin(a)*(pow(x-a, i)) / factorial(i)); else val += (sign*cos(a)*(pow(x-a, i)) / factorial(i)); printf("%d",factorial(i)); } printf("\nTaylor of sin(%g degrees) = %d\n", (x*180.0)/pi, val); } main(){ float pi=3.14159; void McLaurin(float); void Taylor(float); McLaurin(pi); Taylor(pi); } and here's the output: McLaurin of 42 = 0 Enter x in degrees: 42 0.733038-1.00000011.0000001 Taylor of sin(42 degrees) = -1073741824 I suspect the reason for these outrageous numbers goes with the fact that I mixed up my floats and ints? But i just cant figure it out...!! Maybe its a math thing, but its never been a strength of mine let alone program with calculus. Also the Mclaurin fails, how does it equal zero? WTF! Please help correct my noobish code. I am still a beginner...

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  • Function approximation with Maclaurin series

    - by marines
    I need to approx (1-x)^0.25 with given accuracy (0.0001 e.g.). I'm using expansion found on Wikipedia for (1+x)^0.25. I need to stop approximating when current expression is less than the accuracy. long double s(long double x, long double d) { long double w = 1; long double n = 1; // nth expression in series long double tmp = 1; // sum while last expression is greater than accuracy while (fabsl(tmp) >= d) { tmp *= (1.25 / n - 1) * (-x); // the next expression w += tmp; // is added to approximation n++; } return w; } Don't mind long double n. :P This works well when I'm not checking value of current expression but when I'm computing 1000 or more expressions. Domain of the function is <-1;1 and s() calculates approximation well for x in <-1;~0.6. The bigger the argument is the bigger is the error of calculation. From 0.6 it exceeds the accuracy. I'm not sure if the problem is clear enough because I don't know English math language well. The thing is what's the matter with while condition and why the function s() doesn't approximate correctly.

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  • DOM: element created with cloneNode(true) missing element when added to DOM

    - by user149327
    I'm creating a tree control and I'm attempting to use a parent element as a template for its children. To this end I'm using the element.cloneNode(true) method to deep clone the parent element. However when I insert the cloned element into the DOM it is missing certain inner elements despite having an outerHTML value identical to its parent. Surprisingly I observe the same behavior is in IE, Firefox, and Chrome leading me to believe that it is by design. This is the HTML for the node I'm attempting to clone. <SPAN class=node><A class=nodeLink href="/SparklerRestService2.aspx?q={0}" name=http://dbpedia.org/data/Taylor_Swift.rdf> <IMG class=nodeIcon alt="Taylor Swift" src="images/node.png"><SPAN class=nodeText>Taylor Swift</SPAN></A><SPAN class=nodeDescription>Taylor Swift is a swell gall who is realy great.</SPAN></SPAN> Once I've cloned the node using cloneNode(true) I examine the outerHTML property and find that it is indeed identical to the original. <SPAN class=node><A class=nodeLink href="/SparklerRestService2.aspx?q={0}" name=http://dbpedia.org/data/Taylor_Swift.rdf><IMG class=nodeIcon alt="Taylor Swift" src="images/node.png"><SPAN class=nodeText>Taylor Swift</SPAN></A><SPAN class=nodeDescription>Taylor Swift is a swell gall who is realy great.</SPAN></SPAN> However when I insert it into the DOM and inspect the result using FireBug I find that the element has been transformed: <span class="node" style="top: 0px; left: 0px;"<a class=nodeLink href="/SparklerRestService2.aspx?q={0}" name=http://dbpedia.org/data/Taylor_Swift.rdf>Taylor Swift</a><span class="nodeDescription">It's great</span></span> Notice that the grandchildren of the node (the image tag and the span tag surrounding "Taylor Swift") are missing, although strangely the great grandchild "Taylor Swift" text node has made it into the tree. Can anyone shed some light on this behavior? Why would nodes disappear after insertion into the DOM, and why am I seeing the same result in all three major browser engines?

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  • Case insensitive Regex without using RegexOptions enumeration

    - by spoon16
    Is it possible to do a case insensitive match in C# using the Regex class without setting the RegexOptions.IgnoreCase flag? What I would like to be able to do is within the regex itself define whether or not I want the match operation to be done in a case insensitive manner. I would like this regex, taylor, to match on the following values: Taylor taylor taYloR

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  • First Look - Oracle Data Mining

    - by kimberly.billings
    In his blog, JT on EDM, James Taylor shares his analysis of Oracle Data Mining, including its new GUI and Exadata integration. While Oracle Data Mining has been available for a while, it is now easier to access and try via the Amazon Cloud. Using the Oracle 11gR2 Data Mining Amazon Machine Image (AMI), you can launch an Oracle Data Mining-enabled instance directly through Amazon Web Services (AWS) and connect to it using the Oracle Data Miner graphical user interface. The new Oracle Data Mining GUI, which will be available to beta customers soon, provides more graphics, the ability to define, save and share analytical "work flows" to solve business problems, and provides more automation and simplicity. Taylor comments that, "the UI looks to have a nice look and feel including graphical model development flows, easy access to the data, nice little micro graphs when browsing data records and more." On using Oracle Data Mining with Exadata, Taylor writes, "Oracle says that the use of the ODM routines in the Exadata kernel is faster than running a native ODM model in the database by a factor of 2 and that this increases as more joins are used. This could mean that ODM outperforms even third party in-database analytics." Taylor concludes his blog with a positive overall review, stating that "ODM is a nice product for Oracle database customers and well worth looking into. The new UI will only make it more so." Read the blog. var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www."); document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E")); try { var pageTracker = _gat._getTracker("UA-13185312-1"); pageTracker._trackPageview(); } catch(err) {}

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  • How to get only one row for each distinct value in the column ?

    - by Chavdar
    Hi Everybody, I have a question about Access.If for example I have a table with the following data : NAME | ADDRESS John Taylor | 33 Dundas Ave. John Taylor | 55 Shane Ave. John Taylor | 786 Edward St. Ted Charles | 785 Bloor St. Ted Charles | 90 New York Ave. I want to get one record for each person no matter of the address.For example : NAME | ADDRESS John Taylor | 33 Dundas Ave. Ted Charles | 90 New York Ave. Can this be done with queries only ? I tried using DISTINCT, but when I am selecting both columns, the combination is allways unique so I get all the rows. Thank you !

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  • Jquery Flexslider - can't see navigational images (manualControl)

    - by Kim Thomas
    I've spent a lot of time looking at the post on 3/13/12 re: manual controls, but isn't getting me all the way there...probably because I don't know jquery. Sorry, newbie on board. I'm trying to get the right/left arrows to show, as well as the 1, 2, 3...at the bottom. They are there, I see the lists on Firebug, just don't know how to add them to the "hook" (?) so they appear. Here is the code I have in header: <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js" type="text/javascript"></script> <script src="jquery.flexslider.js"></script> <script type="text/javascript" charset="utf-8"> $(window).load(function() { $('.flexslider').flexslider({ animation: "slide", slideshow: false, controlNav: true, manualControls: ".flex-control-nav li a", controlsContainer: ".flex-container" }); }); </script> Here is my html: <div class="flex-container"> <div class="flexslider"> <ul class="slides"> <li><img src="images/tah_home.jpg" alt="taylor art house home page" width="600" height="320"/> <p class="flex-caption">Taylor Art House Home Page</p></li> <li><img src="images/tah_blog.jpg" alt="taylor art house blog page" width="600" height="320" /> <p class="flex-caption">We created a blog that fits seemlessly into Taylor Art House's look</p></li> <li><img src="images/tah_artwork_page.jpg" alt="taylor art house art page" width="600" height="320" /> <p class="flex-caption">One of Taylor Art House's gallery pages, using a Wordpress plugin</p></li> <li><img src="images/tah_arch_portfolio.jpg" alt="jon taylor architecture portfolio page" width="600" height="320" /> <p class="flex-caption">We created links to toggle from TAH to Jon Taylor Architecture</p></li> </ul> </div><!--end flexsider--> </div><!--end flex-container--> Here is the Flexslider CSS: /* * jQuery FlexSlider v1.8 * http://www.woothemes.com/flexslider/ * * Copyright 2012 WooThemes * Free to use under the MIT license. * http://www.opensource.org/licenses/mit-license.php */ /* Browser Resets */ .flex-container a:active, .flexslider a:active, .flex-container a:focus, .flexslider a:focus {outline: none;} .slides, .flex-control-nav, .flex-direction-nav {margin: 0; padding: 0; list-style: none;} /* FlexSlider Necessary Styles *********************************/ .flexslider { width: 100%; margin: 0; padding: 0; } .flexslider .slides > li { display: none; -webkit-backface-visibility: hidden; } /* Hide the slides before the JS is loaded. Avoids image jumping */ .flexslider .slides img { max-width: 100%; display: block; } .flex-pauseplay span { text-transform: capitalize; } /* Clearfix for the .slides element */ .slides:after { content: "."; display: block; clear: both; visibility: hidden; line-height: 0; height: 0; } html[xmlns] .slides { display: block; } * html .slides { height: 1%; } /* No JavaScript Fallback */ /* If you are not using another script, such as Modernizr, make sure you * include js that eliminates this class on page load */ .no-js .slides > li:first-child { display: block; } /* FlexSlider Default Theme *********************************/ .flexslider { width: 600px; background: #fff; border: 4px solid #999; position: relative; margin: 30px 0; -webkit-border-radius: 5px; -moz-border-radius: 5px; -o-border-radius: 5px; border-radius: 5px; zoom: 1; } .flexslider .slides { zoom: 1; } .flexslider .slides > li { position: relative; } /* Suggested container for "Slide" animation setups. Can replace this with your own, if you wish */ .flex-container { zoom: 1; position: relative; margin-left:100px; } /* Caption style */ /* IE rgba() hack */ .flex-caption { background:none; -ms-filter:progid:DXImageTransform.Microsoft.gradient(startColorstr=#4C000000,endColorstr=#4C000000); filter:progid:DXImageTransform.Microsoft.gradient(startColorstr=#4C000000,endColorstr=#4C000000); zoom: 1; } .flex-caption { width: 96%; padding: 2%; margin: 0; position: absolute; left: 0; bottom: 0; background: rgba(0,0,0,.3); color: #fff; text-shadow: 0 -1px 0 rgba(0,0,0,.3); font-size: 14px; line-height: 18px; } /* Direction Nav */ .flex-direction-nav { height: 0; } .flex-direction-nav li a { width: 52px; height: 52px; margin: -13px 0 0; display: block; background: url(theme/bg_direction_nav.png) no-repeat; position: absolute; top: 50%; cursor: pointer; text-indent: -999em; } .flex-direction-nav li .next { background-position: -52px 0; right: -21px; } .flex-direction-nav li .prev { left: -20px; } .flex-direction-nav li .disabled { opacity: .3; filter:alpha(opacity=30); cursor: default; } /* Control Nav */ .flex-control-nav { width: 100%; position: absolute; bottom: -30px; text-align: center; } .flex-control-nav li { margin: 0 0 0 5px; display: inline-block; zoom: 1; *display: inline; } .flex-control-nav li:first-child { margin: 0; } .flex-control-nav li a { width: 13px; height: 13px; display: block; background: url(theme/bg_control_nav.png) no-repeat; cursor: pointer; text-indent: -999em; } .flex-control-nav li a:hover { background-position: 0 -13px; } .flex-control-nav li a.active { background-position: 0 -26px; cursor: default; } Here is how it appears in Firebug: <div class="flex-container"> <div class="flexslider" style="overflow: hidden;"> <ul class="slides" style="width: 1200%; margin-left: -1800px;"> <li class="clone" style="width: 600px; float: left; display: block;"> <li style="width: 600px; float: left; display: block;"> <li style="width: 600px; float: left; display: block;"> <li style="width: 600px; float: left; display: block;"> <li style="width: 600px; float: left; display: block;"> <li class="clone" style="width: 600px; float: left; display: block;"> </ul> </div> <ol class="flex-control-nav"> <li> <a class="">1</a> </li> <li> <li> <li> </ol> <ul class="flex-direction-nav"> <li> <a class="prev" href="#">Previous</a> </li> <li> <a class="next" href="#">Next</a> </li> </ul> </div> Finally, here is a link to the jsFiddle file (I saw someone wanted that in other flexslider post): http://jsfiddle.net/kthms/Wxmsp/ Link to page: http://www.kajortdesigns.com/tah.php I've tried every combo of class from the CSS in the manualControl: "", but I'm just guessing. If anyone can help this newbie out, I would be very appreciative. Explicit instructions are always appreciated.

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  • How to Get All the Windows 8 Editions on One Install Disk

    - by Taylor Gibb
    There are a lot of different versions of Windows, but you probably didn’t know that short of the Enterprise edition, the disc or image that you own contains all versions for that architecture. Read on to see how we can use them to make a universal Windows 8 install disc. Things You Will Need A x86 Version of Windows 8 A x64 Version of Windows 8 A x86 Version of Windows 8 Enterprise A x64 Version of Windows 8 Enterprise A Windows 8 PC Note: While we will use all the images above you don’t really need the Enterprise Edition. You could always leave out parts of the tutorial if you know what you are doing, if you are not comfortable with that and still want to follow through you could always grab the Enterprise evaluation images that are available for free to the public, on MSDN. Getting Started To get started you will need to Download the Windows 8 ADK from Microsoft. Once downloaded go ahead and install it, you will only need the Deployment tools so be sure to uncheck the rest of the options. Lastly you will also need to create the following folder structure on the root of your C:\ drive to make things a bit easier. C:\Windows8Root C:\Windows8Root\x86 C:\Windows8Root\x64 C:\Windows8Root\Enterprisex86 C:\Windows8Root\Enterprisex64 C:\Windows8Root\Temp C:\Windows8Root\Final OK lets get started. Making The Image The first thing we need to do is create a base image, so mount the x86 version of Windows 8 and copy its files to: C:\Windows8Root\Final Now move the install.wim file from: C:\Windows8Root\Final\sources To: C:\Windows8Root\x86 Next go ahead and copy the install.wim file from the other 3 images, Windows 8 x64, Windows 8 Enterprise x86 and Windows 8 Enterprise x64 to the respective folders in Windows8Root, the install.wim file can be located at: D:\sources\install.wim Note: The above assumes that the images are always mounted at drive D. Remember that each install.wim is different so don’t copy them to the wrong directories or the rest of the tutorial wont work. Next switch to the Metro Start Screen and open the Deployment and Imaging Tools Environment. Note: If you are not a local administrator on your PC, you will need to right-click on it and choose to run it as an administrator. Now run the following commands: Dism /Export-Image /SourceImageFile:c:\Windows8Root\x86\install.wim /SourceIndex:2 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8″ /compress:maximum Dism /Export-Image /SourceImageFile:c:\Windows8Root\x86\install.wim /SourceIndex:1 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8 Pro” /compress:maximum Dism /Export-Image /SourceImageFile:c:\Windows8Root\x86\install.wim /SourceIndex:1 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8 Pro with Media Center” /compress:maximum Dism /Export-Image /SourceImageFile:c:\Windows8Root\Enterprisex86\install.wim /SourceIndex:1 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8 Enterprise” /compress:maximum Dism /Export-Image /SourceImageFile:c:\Windows8Root\x64\install.wim /SourceIndex:2 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8″ /compress:maximum Dism /Export-Image /SourceImageFile:c:\Windows8Root\x64\install.wim /SourceIndex:1 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8 Pro” /compress:maximum Dism /Export-Image /SourceImageFile:c:\Windows8Root\x64\install.wim /SourceIndex:1 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8 Pro with Media Center” /compress:maximum Dism /Export-Image /SourceImageFile:c:\Windows8Root\Enterprisex64\install.wim /SourceIndex:1 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8 Enterprise” /compress:maximum Next navigate to: C:\Windows8Root\sources\ And create a new text file. You will need to call it: EI.cfg Then edit it to look like the following: The last thing we need to do is work some magic to get Windows Media Center added to the WMC editions of Windows 8. For that I have written a little script to make it easier for everybody, you can grab it here. Once you have downloaded it extract it. In order to use it right-click in the bottom left hand corner of the screen, and open an elevated command prompt. Then go ahead and paste the following into the command prompt window. powershell.exe -ExecutionPolicy Unrestricted -File C:\Users\Taylor\Documents\HTGWindows8Converter.ps1 Note: You will need to replace the path to the script, another thing to note is that if the path you replace it with has spaces you will need to enclose the path in quotes. The script should kick off straight away and has some progress bars you can watch while it does its thing. Half way through another Window will pop open, which will start creating your final ISO image. When its complete, close the command prompt and you should have an ISO image on the root of your C drive called: HTGWindows8.iso That’s all there is to it. 7 Ways To Free Up Hard Disk Space On Windows HTG Explains: How System Restore Works in Windows HTG Explains: How Antivirus Software Works

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  • iPhone zoom to userLocation

    - by Taylor Satula
    Hi, I need help making my iPhone app zoom to the users current location. I have seen this answered before on StackOverflow ( http://stackoverflow.com/questions/2423236/zoom-on-userlocation )but I have no idea what I am doing when it comes to iPhone development (I make websites not iPhone apps). I need it explained extremely simply, down to where the code snippets go starting from a blank project. Any help is very much appreciated. -- Taylor

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  • Cut Caseload Costs, Speed Service Delivery For Social Services

    - by michael.seback
    Lower Caseload Costs, Speedier Service Delivery with New Oracle Social Services Solution Oracle has just introduced a new solution for social services agencies that's designed to help case workers address the challenges of rising workloads and growing demands by citizens for additional services. In the past, IT departments developed custom software in an effort to meet program outcomes. "Because this capability is out of the box with the Oracle solution, there's less complexity for organizations and an overall lower total cost of ownership," says Kimberly Ellison-Taylor, Oracle's executive director of health and human services. "Self service brings costs down to just pennies per interaction and makes it possible for clients to receive government services more quickly," Ellison-Taylor says. read more

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  • Thank You For Visiting Us At Oracle OpenWorld And JavaOne

    - by Brandye Barrington
    Thanks to everyone who visited us at the Oracle OpenWorld and JavaOne conferences last week. We always enjoy putting faces with names and meeting those of you who are certified or are interested in Certification. Personally, I spent my week on sunny Taylor street at the Java Certification Zone in Taylor Street Cafe.  I talked to over 100 people last week about certification and handed out over 65 ribbons. The Oracle Certification Lounge at OpenWorld, at Moscone South enjoyed more than 200 visitors over the week. Both locations offered scheduled speakers and available experts, in addition to answers to all of your certification questions and account help when needed. We look forward to this opportunity every year to connect with you face to face. If you didn't make it out this year, we hope to see you next year - perhaps we will be so lucky as to enjoy another unseasonably warm week in San Francisco! Stay tuned to our blog for some customer success stories that we were able to record last week.

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  • Maven 3 - duplicate declaration of version

    - by Taylor Leese
    I just upgraded to m2eclipse version 0.10 which includes an embedded Maven 3 and I'm now getting the following error when trying to run a build. I've already set Maven-Installations to my Maven 2 installation, but it had no effect. How do I resolve this? [INFO] Scanning for projects... [ERROR] The build could not read 1 project -> [Help 1] [ERROR] The project com.stuff:sutff-web:0.0.1-SNAPSHOT (C:\development\taylor\stuff\pom.xml) has 1 error [ERROR] 'dependencies.dependency.(groupId:artifactId:type:classifier)' must be unique: com.google.appengine:appengine-api-labs:jar -> duplicate declaration of version ${gae.version} [ERROR] [ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch. [ERROR] Re-run Maven using the -X switch to enable full debug logging. [ERROR] [ERROR] For more information about the errors and possible solutions, please read the following articles: [ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/ProjectBuildingException

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  • How to get the Blur event to fire for the document on the iPhone?

    - by Ian Storm Taylor
    Does anyone know how to get the blur event to fire on the document for the iPhone? I'm trying to get it to fire either when a user changes windows in Safari, or when they open their bookmarks or when they decide to add the page to their homescreen. But none of these are firing it. Here's my code: $(document).blur( function () { document.title = "Ian Taylor"; }); I've tried "document", "window", "'body'". Nothing seems to work.

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  • Runge-Kutta (RK4) integration for game physics

    - by Kai
    Gaffer on Games has a great article about using RK4 integration for better game physics. The implementation is straightforward but the math behind it confuses me. I understand derivatives and integrals on a conceptual level but I haven't manipulated equations in a long time. Here's the brunt of Gaffer's implementation: void integrate(State &state, float t, float dt) { Derivative a = evaluate(state, t, 0.0f, Derivative()); Derivative b = evaluate(state, t+dt*0.5f, dt*0.5f, a); Derivative c = evaluate(state, t+dt*0.5f, dt*0.5f, b); Derivative d = evaluate(state, t+dt, dt, c); const float dxdt = 1.0f/6.0f * (a.dx + 2.0f*(b.dx + c.dx) + d.dx); const float dvdt = 1.0f/6.0f * (a.dv + 2.0f*(b.dv + c.dv) + d.dv) state.x = state.x + dxdt * dt; state.v = state.v + dvdt * dt; } Can anybody explain in simple terms how RK4 works? Specifically, why are we averaging the derivatives at 0.0f, 0.5f, 0.5f, and 1.0f? How is averaging derivatives up to the 4th order different from doing a simple euler integration with a smaller timestep? After reading the accepted answer below, and several other articles, I have a grasp on how RK4 works. To answer my own questions: Can anybody explain in simple terms how RK4 works? RK4 takes advantage of the fact that we can get a much better approximation of a function if we use its higher-order derivatives rather than just the first or second derivative. That's why the Taylor series converges much faster than Euler approximations. (take a look at the animation on the right side of that page) Specifically, why are we averaging the derivatives at 0.0f, 0.5f, 0.5f, and 1.0f? The Runge-Kutta method is an approximation of a function that samples derivatives of several points within a timestep, unlike the Taylor series which only samples derivatives of a single point. After sampling these derivatives we need to know how to weigh each sample to get the closest approximation possible. An easy way to do this is to pick constants that coincide with the Taylor series, which is how the constants of a Runge-Kutta equation are determined. This article made it clearer for me: http://web.mit.edu/10.001/Web/Course%5FNotes/Differential%5FEquations%5FNotes/node5.html. Notice how (15) is the Taylor series expansion while (17) is the Runge-Kutta derivation. How is averaging derivatives up to the 4th order different from doing a simple euler integration with a smaller timestep? Mathematically it converges much faster than doing many Euler approximations. Of course, with enough Euler approximations we can gain equal accuracy to RK4, but the computational power needed doesn't justify using Euler.

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  • Errors not being redirected to an Http handler if redirectMode="ResponseRewrite"

    - by Luk
    I see similar questions, but it looks like there were due to an unrelated issue. in 3.5, I have a custom error handler that logs errors and redirects users. My web.config is set up as such: <httpHandlers> <add path="error.ashx" type="MySite.Tools.WebErrorLogger, MySite.Tools" verb="*"/> </httpHandlers> <customErrors mode="On" defaultRedirect="error.ashx" redirectMode="ResponseRewrite"> </customErrors> When redirectMode is set to "ResponseRedirect", everything works fine (but Server.GetLastError() being null but that seems to be intended) However, when using ResponseRewrite, my handler is not called and I see ASP.Net default error pages. Any idea on how I could do this? (I unfortunately can't use either an aspx page or do my error handling in global.asax due to other constraints)

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  • Grails + GAE - Issue using app.servlet.version=2.5

    - by Taylor L
    Updating the servlet version in application.properties to 2.5 has no affect on the generated web.xml. The generated web.xml is still version 2.4. app.servlet.version=2.5 Also, if I try to execute "run-app" I get the exception below: Running Grails application.. Starting AppEngine generated indices thread. Starting reload monitor thread. [java] Jan 26, 2010 5:27:05 AM com.google.apphosting.utils.jetty.JettyLogger warn [java] WARNING: Failed startup of context com.google.apphosting.utils.jetty.DevAppEngineWebAppContext@4178460d{/,C:\Users\Taylor Leese\workspace\test-gae\web-app} [java] java.lang.IllegalStateException: No such servlet: grails [java] at org.mortbay.jetty.servlet.ServletHandler.updateMappings(ServletHandler.java:953) [java] at org.mortbay.jetty.servlet.ServletHandler.setServletMappings(ServletHandler.java:1037) [java] at org.mortbay.jetty.webapp.WebXmlConfiguration.initialize(WebXmlConfiguration.java:305) [java] at org.mortbay.jetty.webapp.WebXmlConfiguration.configure(WebXmlConfiguration.java:222) [java] at org.mortbay.jetty.webapp.WebXmlConfiguration.configureWebApp(WebXmlConfiguration.java:180) [java] at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1215) [java] at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:500) [java] at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:448) [java] at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:40) [java] at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:117) [java] at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:40) [java] at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:117) [java] at org.mortbay.jetty.Server.doStart(Server.java:217) [java] at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:40) [java] at com.google.appengine.tools.development.JettyContainerService.startContainer(JettyContainerService.java:188) [java] at com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:120) [java] at com.google.appengine.tools.development.DevAppServerImpl.start(DevAppServerImpl.java:217) [java] at com.google.appengine.tools.development.DevAppServerMain$StartAction.apply(DevAppServerMain.java:162) [java] at com.google.appengine.tools.util.Parser$ParseResult.applyArgs(Parser.java:48) [java] at com.google.appengine.tools.development.DevAppServerMain.<init>(DevAppServerMain.java:113) [java] at com.google.appengine.tools.development.DevAppServerMain.main(DevAppServerMain.java:89) [java] The server is running at http://localhost:8080/ Any ideas how to resolve these issues?

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  • Using JCA Adapter with OSB 11.1.1.3

    - by James Taylor
    In OSB 10g to use the JCA adapters you were required to use JDeveloper to create the necessary WSDLs and XSDs etc using the associated adapter wizard. These files were imported into Oracle Workshop (Eclipse) and used to create the business service as you would any other web service. In 11g unfortunately JDeveloper is still required. The process has changed slightly as described below. As an example I have used the JCA DB adapter as an example. Start JDeveloper 11.1.1.3 Create a new SOA Application Create a new SOA Project and call it DBAdapters. Choose the Empty Composite Template Drag a Database Adapter Component to the External References panel on the composite. Provide a service name. Create a new database connection, or use an existing one Take note of the JNDI Name, e.g. eis/DB/MyConnection This will be used to configure the DB connection in the WebLogic Console. In my example I use a stored procedure, but you can use what ever operation you require. Please refer to the following link for other options: User's Guide for Technology Adapters Select a schema and stored procedure Once the procedure has been selected, accept the defaults and finish. Startup your OEPE version of Eclipse. Create a new Oracle Service Bus Configuration Project (you can use an existing project if you have one) Create a new Oracle Service Bus Project in the configuration project created above. Instead of importing the WSDL and XSD files you import the jca file created in JDeveloper. In Eclipse right click the Oracle Service Bus Project and select Import –> Import    Choose File System Browse to the directory where JDeveloper stores its project Select the jca, wsdl, and xsd files based on the service you created in step 5. Also check the ‘Create selected folders only’ radio button. When you import you may have a little red x indicating the files are invalid. This is due to the location of the files. Open the invalid files and fix the path in relation to where you store your files in the OSB project.   Once you have the files all valid, Right-Click the jca file and select Oracle Service Bus –> Generate Service. This will create a new Business Service. In the WebLogic Console configure the JNDI name defined in step 7. You can now deploy your project and test

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  • Will it be possible to use a non-pae kernel in 12.10

    - by Roland Taylor
    I know that Ubuntu +1 questions are frowned upon, but this I believe is a fair exception. Currently I have 2 systems running Ubuntu 12.10, and one of them has a Pentium M that doesn't support PAE (strange I know, but true). This has meant in the past that I had to rely on a custom iso to install Ubuntu a similar system,and so this time I went with Xubuntu 12.04. My question is 2 fold, but really one question: Is it/will it be possible to install a non-pae version of the 12.10 kernel from the standard repositories? If no, how can I get such a kernel? (Is there a PPA with such a kernel available?). NB: Before anyone suggests that I just install this package: http://packages.ubuntu.com/quantal/linux-image-generic, please note that this comes with PAE enabled. P.S. Yes, I have Googled. I haven't found the answer.

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  • Ubuntu Installation Help for an IBM R31 Thinkpad

    - by David Taylor
    I recently acquired an old IBM R31 Thinkpad, and I'd figure I'd install Lubuntu on it. I've followed the quick steps for USB installation on the help wiki page, but I can't seem to get it to boot from my formatted flash drive. I've checked the boot priority on the BIOS page, but the option to boot from USB doesn't even seem to be there. The only bootable options are legacy and USB floppy drives. The CD drive is shot, so I can't install from there either. Do I have any other options for installation without having to pay for a floppy drive or a replacement CD drive? The wiki pages mentions something about installation from within Windows. Would it be possible to remove Windows using this option, or would it just create a partition? Thanks

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