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  • Why does derivative trading position always require C++ knowledge?

    - by Jeffrey
    I’ve never worked in trading environment before and I was curious to see that few of the trading houses seem to use C# but most of them do heavily rely on C++. Why is it? Is it because C++ is better performance wise? Is it because of legacy code base? Is it because cross platform issue? What about dynamic languages (ruby, python)? Are they too slow for this kind of work in terms of performance? Updated: If realibility and performance are important would "Erlang" be the "next big thing" in trading platform?

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  • JPA hibernate OneToOne mapping

    - by Stupidfrog
    enviroment: hibernate 4.1.6.final spring 3.1.2.release spring jpa 1.1.0.release postgresql 9.1-901-1.jdbc4 there is 2 table public A { private Long id; private Long name; } public B { private Long id; private Long table_a_id; } the A.id and B.id is sequential, unique , but no related.(means they are separately id for their own table). how to do mapping? i have tried some method, however the result is not i wanted, because it bind wrong. for example: public A { .... @OneToOne @JoinColumn(name = "id") private B table_b } public B { ... @JsonIgnore @OneToOne(mappedBy = "table_b") private A table_a; } when i query A the result is { "id":5, "table_b":{ "id":5, "table_a_id":4 } } obviously the data join by using their id but not joining using table_a_id. what i expect is { "id":4, "table_b":{ "id":5, "table_a_id":4 } } so can somebody teach me that, how to map this 2 table by using table b table_a_id(foregin key)

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  • How to display how many times each records in a table used by other table

    - by Fredy
    I have a problem with my query, below are two tables that tbl_tag and tbl_tag_usedby. I want to show how much of each record in tbl_tag used by record in tbl_tag_usedby. Here is a query that I use: SELECT t.*, COUNT(u.tagid) AS totale FROM tbl_tag t LEFT JOIN tbl_tag_usedby u ON u.tagid = t.id AND t.status =1 GROUP BY u.tagid and the results are as below: In this case the record id from 2 to 6 do not appear in the query results, I want record id from 2 to 6 are also shown and on the field "totale" its value is 0. Can anyone help me?

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  • What grid distributed computing frameworks are currently favoured for trading systems

    - by Rich
    There seems to a quite a few grid computing frameworks out there, but which ones are actually being used to any great extent by the investment banks for purposes of low latency distributing calculation? I'd be interested to hear answers covering both windows,Linux and cross platform. Also, what RPC mechanisms seem to be favoured most? I've heard that for reason of low latency and speed, the calculations themselves are quite often written in C++/C as calculations running on VMs are several orders of magnitude slower than native code. Does this seem to be a common scenario in practice? e.g distributed .NET grid framework running calculations written in native c++/c?

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  • Browser based online game question

    - by Emre
    I am developing a small browser based game in asp.net. Think of a game room which has a capaticy of 22 players and players join the room by clicking a button. ( I am saving the number of players in the room in database) I need to call a method when the number of players in the room is 22. The problem is I don't know how to control the number of players in the room. I mean I think like there need to be a bacground code which has to run all the time at the server and that code controls the number and call the function. It's my first web project(school project) and I hope you all can help me.

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  • Add all lines multiplied by another line in another table

    - by russell
    Hi, I hope I can explain this good enough. I have 3 tables. wo_parts, workorders and part2vendor. I am trying to get the cost price of all parts sold in a month. I have this script. $scoreCostQuery = "SELECT SUM(part2vendor.cost*wo_parts.qty) as total_score FROM part2vendor INNER JOIN wo_parts ON (wo_parts.pn=part2vendor.pn) WHERE workorder=$workorder"; What I am trying to do is each part is in wo_parts (under partnumber [pn]). The cost of that item is in part2vendor (under part number[pn]). I need each part price in part2vendor to be multiplied by the quantity sold in wo_parts. The way all 3 tie up is workorders.ident=wo_parts.workorder and part2vendor.pn=wo_parts.pn. I hope someone can assist. The above script does not give me the same total as when added by calculator.

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  • holding session state with zend framework in iframe?

    - by princyp
    I have a php site optimized for iphone, its currently running inside of an iframe in a uiwebview objective c wrapper. Everything currently works except for the sessions inside of the iframe, Im assuming this is due to the cross domain issue with iframes and sessions? my solution is to save the sessions to the db. Is this the best solution? Will this even solve my problem? should I use memcache instead? are there any good tutorials for doing this? I havent been able to find an easy to implement solution for saving the session data, im a bit confused by the bootstrap.php and I keep getting this error when I try to add session saving: 'no adapter found for Zend_Session_SaveHandler_DbTable' any help would be greatly appreciated, thank you

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  • ActiveX doesn't show up in Browser

    - by Boller
    Hi, i'm trying to put an activeX object on an asp-webpage. it already worked good a week ago, but now the object isn't showing up anymore. already made a little asp testing-project....just an asp-page and a activex control, containing a button and a label. but when i call up the page in the browser, there is only a white area with a little icon in the upper left corner, showing a red dot, a green triangle and a blue rectangle.... what does that mean? object not found? object blocked by IE? or what exactly does this icon stand for? i always thoght that an missing object is represented by an empty area with a little red cross in it. =/

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  • Problem with SQLite executemany

    - by Strider1066
    I can't find my error in the following code. When it is run a type error is given for line: cur.executemany(sql % itr.next()) = 'function takes exactly 2 arguments (1 given), import sqlite3 con = sqlite3.connect('test.sqlite') cur = con.cursor() cur.execute("create table IF NOT EXISTS fred (dat)") def newSave(className, fields, objData): sets = [] itr = iter(objData) if len(fields) == 1: sets.append( ':' + fields[0]) else: for name in fields: sets.append( ':' + name) if len(sets)== 1: colNames = sets[0] else: colNames = ', '.join(sets) sql = " '''insert into %s (%s) values(%%s)'''," % (className, colNames) print itr.next() cur.executemany(sql % itr.next()) con.commit() if __name__=='__main__': newSave('fred', ['dat'], [{'dat':1}, {'dat':2}, { 'dat':3}, {'dat':4}]) I would appreciate your thoughts.

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  • Best Practice: Accessing radio button group

    - by seth
    Looking for the best, standards compliant, cross browser compatible, forwards compatible way to access a group of radio buttons in the DOM (this is closely related to my other most recent post...), without the use of any external libraries. <input type="radio" value="1" name="myRadios" />One<br /> <input type="radio" value="2" name="myRadios" />Two<br /> I've read conflicting information on getElementsByName(), which seems like the proper way to do this, but I'm unclear if this is a standards compliant, forwards compatible solution. Perhaps there is a better way?

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  • Is is possible to parse a web page from the client side for a large number of words and if so, how?

    - by Technoh
    I have a list of keywords, about 25,000 of them. I would like people who add a certain < script tag on their web page to have these keywords transformed into links. What would be the best way to go and achieve this? I have tried the simple javascript approach (an array with lots of elements and regexping/replacing each) and it obviously slows down the browser. I could always process the content server-side if there was a way, from the client, to send the page's content to a cross-domain server script (I'm partial to PHP but it could be anything) but I don't know of any way to do this. Any other working solution is also welcome.

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  • Python CSV file processing

    - by kingwarchief
    I just got introduced to python, the first language I get to learn, and I have this question below: I have an excel based CSV file with two columns (or rows, Pythonically) that I am working on. What I need to do is to perform some operations so that I can compare the two data entries in each 'row'. To be more precise, one column has constant numbers all the way down, whereas the other column varies. So I need to count the number of times the varying column data entry values crosses the constant value on the other column. For example: Varying Column; Constant Column 24 25 26 25 crosses 27 25 26 25 25.5 25 23 25 crossed 26 25 crossed So in this case the number of times there is a cross

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  • Dynamic order by without using dynamic sql ?

    - by Rohit
    I have the following stored procedure which can be sorted ascending and descending on TemplateName,CreatedOn and UploadedBy. The following SP when runs doesnot sort records.if i replace 2,3,4 by columnname, i got an error message "Conversion failed when converting the nvarchar value 'Test Template' to data type int.".Please suggest how to achieve sorting. CREATE PROCEDURE [dbo].[usp_SEL_GetRenderingTemplate] ( @facilityID INT, @sortOrder VARCHAR(5), @sortExpression VARCHAR(100), @errorCode INT OUTPUT ) AS BEGIN SET NOCOUNT ON ; BEGIN TRY SET @sortOrder = CASE @sortOrder WHEN 'Ascending' THEN 'ASC' WHEN 'Descending' THEN 'DESC' ELSE 'ASC' END SELECT TemplateID, TemplateName, CreatedOn, ( [user].LastName + ' ' + [user].FirstName ) AS UploadedBy FROM Templates INNER JOIN [user] ON [user].UserID = Templates.CreatedBy WHERE facilityid = @facilityID ORDER BY CASE WHEN @sortExpression = 'TemplateName' AND @sortOrder = 'ASC' THEN 2 WHEN @sortExpression = 'CreatedOn' AND @sortOrder = 'ASC' THEN 3 WHEN @sortExpression = 'UploadedBy' AND @sortOrder = 'ASC' THEN 4 END ASC, CASE WHEN @sortExpression = 'TemplateName' AND @sortOrder = 'DESC' THEN 2 WHEN @sortExpression = 'CreatedOn' AND @sortOrder = 'DESC' THEN 3 WHEN @sortExpression = 'UploadedBy' AND @sortOrder = 'DESC' THEN 4 END DESC SET @errorCode = 0 END TRY BEGIN CATCH SET @errorCode = -1 DECLARE @errorMsg AS VARCHAR(MAX) DECLARE @utcDate AS DATETIME SET @errorMsg = CAST(ERROR_MESSAGE() AS VARCHAR(MAX)) SET @utcDate = CAST(GETUTCDATE() AS DATETIME) EXEC usp_INS_LogException 'usp_SEL_GetFacilityWorkTypeList', @errorMsg, @utcDate END CATCH END

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  • C/C++ GUI framework to create distinctive window style

    - by genesys
    Hi! Can someone please tell me a GUI framework (for Windows. doesn't need to be cross platform) that allows me to specify the design of the UI elements very precisely? For example, the Windows and UI elements of Adobe products look different than other Windows applications. I'm looking for a framework that would allow me to create a GUI in that style - or any other style I invent, from the shape of the window, to the visual appearance of any scrollbar, button minimize/maximize buttons and so on. any recommendations? Thanks!

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  • How can I implement "real time" messaging on Google AppEngine?

    - by Freed
    I'm creating a web application on Google AppEngine where I want the user to be notified a quickly as possible after certain events occour. The problem is similar to say a chat server in that I need something happening on one connection (someone is writing a message in a chat room) to propagate to a number of other connections (other people in that chat room gets the message). To get speedy updates from the server to the client I'm planning on using long polling with XmlHttpRequest, hoping that AppEngine won't interfere other than possibly restriing the timeout. The real problem however is efficient notification between connections on AppEngine. Is there any support for this type of cross connection notification on AppEngine that does not involve busy-waiting? The only tools I can think of to do this at all is either using the data storage (slow) or memcache (unreliable), and none of them would let me avoid busy-waiting. Note: I know about XMPP support on AppEngine. It's related, but I want a browser based solution, sending messages to the users by XMPP is not an option.

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  • How to save the world from your computer?

    - by Francisco Garcia
    Sometimes I miss the "help other people" factor within computer related careers. Sure that out there I could find many great projects improving society, but that is not common. However there are little things that we all can do to make this a better place beyond trying to erradicate annoynig stuff such as Visual Basic. You could join a cloud computing network such as World Community Grid to fight cancer. Write a charityware application such as Vim, improve an office IT infrastructure to support telecommuting and reduce CO2 emissions, use an ebook reader for saving paper... what else would you? which projects do you think can have an impact?

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  • How to split movie and play parts to look as a whole?

    - by luksow
    I'm writing software which is demonstraiting video on demand service. One of the feature is something similiar to IIS Smooth Streaming - I want to adjust quality to the bandwith of the client. My idea is, to split single movie into many, let's say - 2 seconds parts, in different qualities and then send it to the client and play them. The point is that for example first part can be in very high quality, and second in really poor (if the bandwith seems to be poor). The question is - do you know any software that allows me to cut movies precisly? For example ffmpeg splits movies in a way that join is visible and really annoying (seconds are the measure of precision). I use qt + phonon as a player if it matters. Or maybe you know any better way to provide such feature, without splitting movie into parts?

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  • CakePHP: Using two tables for a single model

    - by mwaterous
    I'm just picking up development in CakePHP right now so forgive me if this seems obvious; it did to me when I first read about has, belongsTo, hasMany, etc. The problem is I would like to associate two tables with a single model, and was wondering if there was a way to configure this so that when CakePHP did it's queries it automatically performed a join on the two tables. I don't want to create a separate model for the second table as it is merely a meta information table - the master table will contain the primary information required, the meta table will be populated with secondary information that is not required and therefore may or may not be set for every row of the master table.

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  • Project Euler #163 understanding

    - by Paul
    I spent quite a long time searching for a solution to this problem. I drew tons of cross-hatched triangles, counted the triangles in simple cases, and searched for some sort of pattern. Unfortunately, I hit the wall. I'm pretty sure my programming/math skills did not meet the prereq for this problem. So I found a solution online in order to gain access to the forums. I didn't understand most of the methods at all, and some just seemed too complicated. Can anyone give me an understanding of this problem? One of the methods, found here: http://www.math.uni-bielefeld.de/~sillke/SEQUENCES/grid-triangles (Problem C) allowed for a single function to be used. How did they come up with that solution? At this point, I'd really just like to understand some of the concepts behind this interesting problem. I know looking up the solution was not part of the Euler spirit, but I'm fairly sure I would not have solved this problem anyhow.

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  • MySQL : delete from table that is used in the where clause

    - by Eric
    I am writing a small script to synchronize 2 MySQL tables ( t1 to be 'mirrored' to t2 ) In a step I would like to delete rows inside t2 that has been delete in t1 with the same id. I tried this query : delete from t2 where t2.id in ( select t2.id left join t1 on (t1.id=t2.id) where t1.id is null ) But Mysql forbid me to use t2 in the same time in the delete and in the select (sound logical by the way) Of course, I can split the query into 2 queries : first select IDs, then delete rows with these IDs. My question : do you have a cleaner way to delete row from t2 that does not exist anymore in t1 ? with one query only ?

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  • Is it hard problem?

    - by Lukasz Lew
    I can't solve it: You are given 8 integers: A, B, C representing a line on a plane with equation A*x + B*y = C a, b, c representing another line x, y representing a point on a plane The two lines are not parallel therefore divide plane into 4 pieces. Point (x, y) lies inside of one these pieces. Problem: Write a fast algorithm that will find a point with integer coordinates in the same piece as (x,y) that is closest to the cross point of the two given lines. Note: This is not a homework, this is old Euler-type task that I have absolutely no idea how to approach.

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  • Deleting an element from an array in perl

    - by Flamewires
    Hey I'm wondering how i can get this code to work, basically i want to keep the lines of $filename as long as they contain the $user in the path. Sry, perl noob. open STDERR, ">/dev/null"; $filename=`find -H /home | grep $file`; @filenames = split(/\n/, $filename); for $i (@filenames) { if ($i =~ m/$user/) { #keep results } else { delete $i; # does not work. } } $filename = join ("\n", @filenames); close STDERR; I know you can delete like delete $array[index] but I don't have an index with this kind of loop that I know of.

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  • Denormalize for Simplicity: Ungood idea?

    - by yar
    After reading this question, I've learned that denormalization is not a solution for simplicity. What about this case? I have news-articles which have a list of sites-article-will-be-published-to. The latter can be expressed in normalized fashion either by table and a many-to-many relationship (via a cross-table, I think). But the simple solution is to just throw a bunch of booleans for the sites-article-will-be-published-to. Assuming the sites are: small in number will not change over time have no fields themselves, except a name Is this still a terrible idea? The many-to-many relationship seems somewhat cumbersome, but I've done it before in cases like this (and it seemed cumbersome). Note: I'm doing this in Rails, where it's not that painful.

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  • Why doesn't Perl threading work when I call readdir beforehand?

    - by Kevin
    Whenever I call readdir before I create a thread, I get an error that looks like this: perl(2820,0x7fff70c33ca0) malloc: * error for object 0x10082e600: pointer being freed was not allocated * set a breakpoint in malloc_error_break to debug Abort trap What's strange is that it happens when I call readdir before I create a thread (i.e. readdir is not called in any concurrent code). I don't even use the results from readdir, just making the call to it seems to screw things up. When I get rid of it, things seem to work fine. Some example code is below: opendir(DIR, $someDir); my @allFiles = readdir(DIR); close(DIR); my $thread = threads-create(\&sub1); $thread-join(); sub sub1 { print "in thread\n" }

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  • Windows Services -- High availability scenarios and design approach

    - by Vadi
    Let's say I have a standalone windows service running in a windows server machine. How to make sure it is highly available? 1). What are all the design level guidelines that you can propose? 2). How to make it highly available like primary/secondary, eg., the clustering solutions currently available in the market 3). How to deal with cross-cutting concerns in case any fail-over scenarios If any other you can think of please add it here .. Note: The question is only related to windows and windows services, please try to obey this rule :)

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