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Articles indexed in June 2010

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  • What technical skills needed for algorithmic trading, HFT, etc?

    - by alchemical
    I'm interested in getting into developing trading systems, black box, HFT, etc. My primary experience is with C# and .Net (7 years). I've also done some sockets programming. I have some experience in finance working on analysis applications (2 years). My goal is to move into developing automated trading systems for a hedge fund, bank, etc. Is there any way to learn the skills needed for this without somehow getting the job first? I've looked at the open source tradelink, IB interactive brokerage, etc. I'm playing around with this framework, and may hook it up and do some paper trading. However, I'm not sure if this has much relationship with how a well-funded entity would be conducting a high-level automated trading operation. I.e. would the tools and frameworks they prefer be a totally different skill-set? Also wondering if I need to learn C++ and/or Java for these types of apps.

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  • JQuery each loop problem

    - by bhefny
    Hello, I have the following code <div> <a href="#" class="clickMe">test</a> <ul> <li class="action_li">1</li> <li class="action_li">2</li> </ul></div> <div> <a href="#" class="clickMe">test</a> <ul> <li class="action_li">3</li> <li class="action_li">4</li> </ul> and I want to loop on all the <li> that are enclosed with the same <div> as the clicked <a> $("a.clickMe").live("click", function(eve){ eve.preventDefault(); $('.action_li').each(function(index) { console.debug(this); }); }); but of course this will get me all the 4 <li> not the two enclosed so I want to have something that starts with $(this) and ends with .each()

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  • How to triage this MySQL duplicate entry error after running Rails migration?

    - by keruilin
    I get the following error when I try to run this migration: == AddUniquenessConstraintOnAwards: migrating ================================ -- add_index(:awards, [:badge_id, :game_week_id], {:unique=>true, :name=>:game_badge_index}) rake aborted! An error has occurred, all later migrations canceled: Mysql::Error: Duplicate entry '35-8192' for key 'game_badge_index': CREATE UNIQUE INDEX `game_badge_index` ON `awards` (`badge_id`, `game_week_id`) Has anyone encountered? What's the error telling me? How did you troubleshoot it and ultimately fix it?

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  • SQL - Getting Most Recent Date From Multiple Columns

    - by ScottSEA
    Assume a rowset containing the following EntryID Name DateModified DateDeleted ----------------------------------------------- 1 Name1 1/2/2003 NULL 2 Name1 1/3/2005 1/5/2008 3 Name1 1/3/2006 NULL 4 Name1 NULL NULL 5 Name1 3/5/2008 NULL I need to return the largest (i.e. most recent) non-null date from DateModified and DateDeleted, in this case 3/5/2008.

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  • NullPointerException when trying to connect to web service using kSoap method Android

    - by benjamin schultz
    My web service should be returning an integer, but every time i run the code i get the NullPointerException error. Any ideas or help would be very appreciated Here's my code: public class CGCountTest extends Activity { TextView testTV; private static final String NAMESPACE = "http://passport-america.com/webservices/"; private static final String URL = "http://localhost:11746/Service1.asmx"; private static final String SOAP_ACTION = "http://www.passport-america.com/webservices/getCGCount"; private static final String METHOD_NAME = "getCGCount"; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.soap_test); SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME); SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11); envelope.dotNet = true; envelope.setOutputSoapObject(request); HttpTransportSE androidHttpTransport = new HttpTransportSE(URL); try { androidHttpTransport.call(SOAP_ACTION, envelope); java.lang.Integer result = (Integer)envelope.getResponse(); TextView testTV = (TextView)findViewById(R.id.testTV); result.toString(); testTV.setText(result); } catch(Exception e) { testTV.setText(e.getMessage()); } } here's the logcat 06-02 15:13:36.557: WARN/dalvikvm(326): threadid=3: thread exiting with uncaught exception (group=0x4001aa28) 06-02 15:13:36.557: ERROR/AndroidRuntime(326): Uncaught handler: thread main exiting due to uncaught exception 06-02 15:13:36.876: ERROR/AndroidRuntime(326): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.pa.passammain/com.pa.passammain.CGCountTest}: java.lang.NullPointerException 06-02 15:13:36.876: ERROR/AndroidRuntime(326): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2401) 06-02 15:13:36.876: ERROR/AndroidRuntime(326): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2417) 06-02 15:13:36.876: ERROR/AndroidRuntime(326): at android.app.ActivityThread.access$2100(ActivityThread.java:116) 06-02 15:13:36.876: ERROR/AndroidRuntime(326): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794) 06-02 15:13:36.876: ERROR/AndroidRuntime(326): at android.os.Handler.dispatchMessage(Handler.java:99) 06-02 15:13:36.876: ERROR/AndroidRuntime(326): at android.os.Looper.loop(Looper.java:123) 06-02 15:13:36.876: ERROR/AndroidRuntime(326): at android.app.ActivityThread.main(ActivityThread.java:4203) 06-02 15:13:36.876: ERROR/AndroidRuntime(326): at java.lang.reflect.Method.invokeNative(Native Method) 06-02 15:13:36.876: ERROR/AndroidRuntime(326): at java.lang.reflect.Method.invoke(Method.java:521) 06-02 15:13:36.876: ERROR/AndroidRuntime(326): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791) 06-02 15:13:36.876: ERROR/AndroidRuntime(326): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:549) 06-02 15:13:36.876: ERROR/AndroidRuntime(326): at dalvik.system.NativeStart.main(Native Method) 06-02 15:13:36.876: ERROR/AndroidRuntime(326): Caused by: java.lang.NullPointerException 06-02 15:13:36.876: ERROR/AndroidRuntime(326): at com.pa.passammain.CGCountTest.onCreate(CGCountTest.java:46) 06-02 15:13:36.876: ERROR/AndroidRuntime(326): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1123) 06-02 15:13:36.876: ERROR/AndroidRuntime(326): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2364) 06-02 15:13:36.876: ERROR/AndroidRuntime(326): ... 11 more i think my url string may be the problem, but i've tried using my ip with no luck

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  • Factory Method Using Is/As Operator

    - by Swim
    I have factory that looks something like the following snippet. Foo is a wrapper class for Bar and in most cases (but not all), there is a 1:1 mapping. As a rule, Bar cannot know anything about Foo, yet Foo takes an instance of Bar. Is there a better/cleaner approach to doing this? public Foo Make( Bar obj ) { if( obj is Bar1 ) return new Foo1( obj as Bar1 ); if( obj is Bar2 ) return new Foo2( obj as Bar2 ); if( obj is Bar3 ) return new Foo3( obj as Bar3 ); if( obj is Bar4 ) return new Foo3( obj as Bar4 ); // same wrapper as Bar3 throw new ArgumentException(); } At first glance, this question might look like a duplicate (maybe it is), but I haven't seen one exactly like it. Here is one that is close, but not quite: http://stackoverflow.com/questions/242097/factory-based-on-typeof-or-is-a

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  • jQuery tools modal overlay display problem in IE6-8

    - by Michael Stone
    I'm trying to enable the overlay to be modal. It works perfectly fine in FireFox, but the window object is behind the mask when it becomes modal. This prevents any interaction with it and the page is actually useless. I've tried debugging this for a while and can't figure it out. Here is a link to the example on their site: http://flowplayer.org/tools/demos/overlay/modal-dialog.html $.fn.cfwindow = function(btnEvent,modal,draggable){ //error checking if(btnEvent == ""){ alert('Error in window :\n Please provide an id that instantiates the window. '); } if(!modal && !draggable){ $('#'+btnEvent+'[rel]').overlay(); $('#content_overlay').css('cursor','default'); } if(!modal && draggable){ $('#'+btnEvent+'[rel]').overlay(); $('#content_overlay').css('cursor','move'); $('#custom').draggable(); } if(modal){ $('#'+btnEvent+'[rel]').overlay({ // some mask tweaks suitable for modal dialogs mask: { color: '#646464', loadSpeed: 200, opacity: 0.6 }, closeOnClick: false }); $('#content_overlay').css('cursor','default'); //$('#custom').addClass('modal'); } }; That's what I'm referencing when I call through: <script type="text/javascript"> $(document).ready(function(){ $(document).pngFix(); var modal = <cfoutput>#attributes.modal#; var drag = #attributes.draggable#; var btn = '#attributes.selector#'; var src = '#attributes.source#'; var wid = '#attributes.width#'; $('##custom').width(parseInt(wid)); $('div##load_content').load(src); $('##custom').cfwindow(btn,modal,drag,wid); }); </script> CSS for the modal: <style type="text/css"> .modal { display:none; text-align:left; background-color:#FFFFFF; -moz-border-radius:6px; -webkit-border-radius:6px; } </style> Exclude the and the additional pound signs, IE. "##". Screen shot of the problem: http://twitpic.com/1tak06 Note: IE6 and IE8 have the same problem. Any help would be appreciated.

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  • VS2008 -> VS2010 leads to cryptic STL errors

    - by Jakobud
    The following C++ library was successfully compiled in VS2008 http://sourceforge.net/projects/xmlrpcc4win/files/xmlrpcc4win/XmlRpcC4Win1.0.8.zip/download When I open it in VS2010, it goes through the conversion wizard process without any errors. Now, when I attempt to compile it in VS2010, I get some weird STL errors like these: 1>TimXmlRpc.cpp(1018): error C2039: 'back_insert_iterator' : is not a member of 'std' 1>TimXmlRpc.cpp(1018): error C2065: 'back_insert_iterator' : undeclared identifier 1>TimXmlRpc.cpp(1018): error C2275: 'XmlRpcValue::BinaryData' : illegal use of this type as an expression 1>TimXmlRpc.cpp(1018): error C2065: 'ins' : undeclared identifier 1>TimXmlRpc.cpp(1018): error C2039: 'back_inserter' : is not a member of 'std' 1>TimXmlRpc.cpp(1018): error C3861: 'back_inserter': identifier not found 1>TimXmlRpc.cpp(1019): error C2065: 'ins' : undeclared identifier 1>TimXmlRpc.cpp(1031): error C2039: 'back_insert_iterator' : is not a member of 'std' 1>TimXmlRpc.cpp(1031): error C2065: 'back_insert_iterator' : undeclared identifier 1>TimXmlRpc.cpp(1031): error C2275: 'std::vector<_Ty>' : illegal use of this type as an expression 1> with 1> [ 1> _Ty=char 1> ] 1>TimXmlRpc.cpp(1031): error C2065: 'ins' : undeclared identifier 1>TimXmlRpc.cpp(1031): error C2039: 'back_inserter' : is not a member of 'std' 1>TimXmlRpc.cpp(1031): error C3861: 'back_inserter': identifier not found 1>TimXmlRpc.cpp(1032): error C2065: 'ins' : undeclared identifier I'm not sure what to make of some of these. For instance, back_insert_iterator is in fact a member of std, but VS doesn't seem to think it is. How do I fix errors like these? They just don't seem to make much sense so I'm not sure where to begin. Perhaps its something in my project settings? For example, here is line 1018, which gives the std error: std::back_insert_iterator<BinaryData> ins = std::back_inserter(*(u.asBinary)); If anyone could give me some direction I'd appreciate it. I'm new enough to C++ that I'm having a tough time figuring out this one.

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  • Which is the best pick?

    - by Daniel
    Hi, considering I have experience with Java SE: which language should I learn(and is best for that purpose) in order to build web applications some day with it? I have been contemplating PHP and Java EE. The latter does indeed seems as an obvious choice given my Java SE knowledge. But how does it fares in comparison with PHP and how good is it for the aforementioned purpose? If there is a better language for this purpose, feel free to recommend it. Thank you.

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  • PHP database simulation

    - by Emdiesse
    I have a PHP script that works by calling items from a database based upon the time they were placed in there and it deletes them if they are older than 5 minutes. Basically, I want to now simulate what would happen if this database was being updated regularly. So I was considering sticking in some code that loads an XML file then goes through and parses that into the database based upon the time data located within a node of the xml data... but the problem there is I want it to continually loop through an enter this data so it'll never actually run the other processes So I was thinking of having another PHP script do that that could do this independantly of the php script that is going to display this data... In theory: I am looking to have a button that I can press and it will then run some php code to load up an XML file from a directory on my web server and then iterate though the data sending the data, to a database, based upon the time within a node in the PHP script and when the script was first called So back to my page that displayed the data... if I continually hit refresh it will contain different results each time because data is being added by the other process and this php script removes the older data when it is refreshed Any information on this? Is there a way I can silently, and safely, run a php script without it being loaded into a browser... like a thread!?

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  • How can I find out a servlet's URL?

    - by Geo
    Let's say I have this in my web.xml: <servlet> <description></description> <display-name>MainServ</display-name> <servlet-name>MainServ</servlet-name> <servlet-class>MainServ</servlet-class> </servlet> <servlet-mapping> <servlet-name>MainServ</servlet-name> <url-pattern>/MainServ</url-pattern> </servlet-mapping> Imagine I'm in that servlet's doGet method. Is there anyway of getting at the /MainServ value?

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  • How to add parameters to a HTTP GET request in Android?

    - by groomsy
    I have a HTTP GET request that I am attempting to send. I tried adding the parameters to this request by first creating a BasicHttpParams object and adding the parameters to that object, then calling setParams( basicHttpParms ) on my HttpGet object. This method fails. But if I manually add my parameters to my URL (i.e. append '?param1=value1&param2=value2') it succeeds. I know I'm missing something here and any help would be greatly appreciated. Thanks in advance, groomsy

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  • Protecting from crashes (beyond bounds) with [object objectAtIndex:]

    - by Tom
    Hi! I'd like to know if there's a way to verify if an index exists before getting it. So it'd be way to protect my code against: *** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[NSCFArray objectAtIndex:]: index (2) beyond bounds (0)' Like in PHP you can do: isset($object[10]); and it'll return true if it exists. Is there such a method in Objective-C/Cocoa? Thanks!

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  • How to store and locate multiple interface types within a Delphi TInterfaceList

    - by Brian Frost
    Hi, I'm storing small interfaces from a range of objects into a single TInterfaceList 'store' with the intention of offering list of specific interface types to the end user, so each interface will expose a 'GetName' function but all other methods are unique to that interface type. For example here are two interfaces: IBase = interface //---------------------------------------- function GetName : string; //---------------------------------------- end; IMeasureTemperature = interface(IBase) //------------------------------------ function MeasureTemperature : double; //---------------------------------------- end; IMeasureHumidity = interface(IBase) //---------------------------------------- function MeasureHumidity: double; //---------------------------------------- end; I put several of these interfaces into a single TInterfaceList and then I'd like to scan the list for a specific interface type (e.g. 'IMeasureTemperature') building another list of pointers to the objects exporting those interfaces. I wish to make no assumptions about the locations of those objects, some may export more than one type of interface. I know I could do this with a class hierarchy using something like: If FList[I] is TMeasureTemperature then .. but I'd like to do something simliar with an interface type, Is this possible?

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  • Can i have a negative value as constant expression in Scala?

    - by Klinke
    I have an Java-Annotation that return a double value: @Retention(RetentionPolicy.RUNTIME) @Target(ElementType.FIELD) public @interface DoubleValue { double value(); } When i try to attach the annotation to a field in a scala class and the value is negativ like here: class Test { @DoubleValue(-0.05) var a = _ } i get an compiler error with the message: "annotation argument needs to be a constant; found: 0.05.unary_-". I understood that i need a numerical literal and i looked into the Scala Language Specification and it seems, that the - sign is only used for the exponent but not for the mantissa. Does someone has an idea how i can have a negative value as runtime information using annotations? Thanks, Klinke

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  • Intel Unveils 50-Core Supercomputing Processor

    <b>Hardware Central:</b> "Intel has announced a new multi-core processor, and the fact that it was introduced at the International Supercomputing Conference (ISC) instead of the consumer-oriented Computex show taking place at the same time should be an indication of its target market."

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  • SQL Merge Replication - Filter Sets

    - by Refracted Paladin
    I have a "working" Replication Set in SQL 2005 that we use in house to our users at remote branches on SQL Express 2005. I want to apply a filter to our biggest Set to help minimize the bandwidth impact. What I am asking is what considerations do I need to take into account before throwing a filter on there. Will it cause any issues I should be aware of? Does it affect compression adversely. Will everyone need to reinitialize after applying it? Any heads up or insight would be appreciated. Thanks,

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  • Will modules installed by insmod command persist after rebooting?

    - by apache
    There is how the book I'm reading describe the insmod utility: The program loads the module code and data into the kernel, which, in turn, performs a function similar to that of ld, in that it links any unresolved symbol in the module to the symbol table of the kernel. Unlike the linker, however, the kernel doesn’t modify the module’s disk file, but rather an in-memory copy. It looks like it won't persist since it's in-memory, but I'm not sure.

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