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  • Starting a career in quantitative finance

    - by Vitor Braga
    I've been reading John Hull book (Options, Futures and Other Derivatives) mostly on curiosity. I've read other books about financial markets in the past (like Elder's Trading for Living and the novel Reminiscences of a Stock Operator). But I'm really hooked by the John Hull book. My background is mostly scientific computing: number crunching, visualization and image processing. Mostly in C++, with some C, Fortran, Python, Ruby here and there. I've been thinking on moving on to quantitative finance - I'd like to do that. What would be the best way to start? Any tips?

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  • Materialized View does not import properly when importing a db for a second time in another schema [closed]

    - by marinus
    When I import a database with materialized view mv_mt in just one schema there are no errors. create materialized view mv_mt refresh complete next trunc( sysdate ) + 1 as SELECT sysdate, media_type.* from media_type; But when I try to import the same database to a copy in another schema in the same tablespace I get the following errors: IMP-00017: following statement failed with ORACLE error 1: "BEGIN DBMS_JOB.ISUBMIT(JOB=>438,WHAT=>'dbms_refresh.refresh(''"ALEXANDRA"" "."MV_MT"'');',NEXT_DATE=>TO_DATE('2012-07-02:14:22:36','YYYY-MM-DD:HH24:MI:" "SS'),INTERVAL=>'sysdate + 1 / 24 / 60 / 6 ',NO_PARSE=>TRUE); END;" IMP-00003: ORACLE error 1 encountered ORA-00001: unique constraint (SYS.I_JOB_JOB) violated ORA-06512: at "SYS.DBMS_JOB", line 100 ORA-06512: at line 1 IMP-00017: following statement failed with ORACLE error 23421: "BEGIN dbms_refresh.make('"ALEXANDRA"."MV_MT"',list=>null,next_date=>null," "interval=>null,implicit_destroy=>TRUE,lax=>FALSE,job=>438,rollback_seg=>NUL" "L,push_deferred_rpc=>TRUE,refresh_after_errors=>FALSE,purge_option => 1,par" "allelism => 0,heap_size => 0); END;" IMP-00003: ORACLE error 23421 encountered ORA-23421: job number 438 is not a job in the job queue ORA-06512: at "SYS.DBMS_SYS_ERROR", line 86 ORA-06512: at "SYS.DBMS_IJOB", line 793 ORA-06512: at "SYS.DBMS_REFRESH", line 86 ORA-06512: at "SYS.DBMS_REFRESH", line 62 ORA-06512: at line 1 IMP-00017: following statement failed with ORACLE error 23410: "BEGIN dbms_refresh.add(name=>'"ALEXANDRA"."MV_MT"',list=>'"ALEXANDRA"."MV" "_MT"',siteid=>0,export_db=>'ORCL01'); END;" IMP-00003: ORACLE error 23410 encountered ORA-23410: materialized view "ALEXANDRA"."MV_MT" is already in a refresh group ORA-06512: at "SYS.DBMS_SYS_ERROR", line 95 ORA-06512: at "SYS.DBMS_IREFRESH", line 484 ORA-06512: at "SYS.DBMS_REFRESH", line 140 ORA-06512: at "SYS.DBMS_REFRESH", line 125 ORA-06512: at line 1 Anyone any ideas?

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  • May I use full-texted feed for my News Reader app?

    - by Mahdi Ghiasi
    I'm creating a news reader app. (Users will choose sources, but not the exact feed addresses. for example, they can choose Gizmodo but they will not see the exact url of Gizmodo's feed) Some of sources are giving partial feeds, and user must go to their website to read the complete article. My question is, May I make a fulltext version of their feed (for example, using this service) and use it instead of their feed in my News reader categories? Am I legally/ethically allowed to do this? What about using some other service like Readability? (Readability gives HTML page instead of feed as input, but anyway, output will be clean article without any advertises or such) Please note that some of these partial feeds may have some advertises inside, but the fulltext feed generators usually remove that advertises.

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  • IL and case-sensitivity

    - by Ali .NET
    Quoted from A Brief Introduction To IL code, CLR, CTS, CLS and JIT In .NET CLS stands for Common Language Specifications. It is a subset of CTS. CLS is a set of rules or guidelines which if followed ensures that code written in one .NET language can be used by another .NET language. For example one rule is that we cannot have member functions with same name with case difference only i.e we should not have add() and Add(). This may work in C# because it is case-sensitive but if try to use that C# code in VB.NET, it is not possible because VB.NET is not case-sensitive. Based on above text I want to confirm two points here: Does the case-sensitivity of IL is a condition for member functions only, and not for member properties? Is it true that C# wouldn't be inter-operable with VB.NET if it didn't take care of the case sensitivity?

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  • Revision Methodology for Developer Post as Entry Level

    - by Demla Pawan
    I had revised all basic concepts of my computer science ciriculum like: Core Java(basics),SQL(basics),C++(basics),XHTML,PHP(basics),Datastructures(basics) and what I need to do,and How to do, as their may be fault in my preparation methods for revision session's, So can Anybody suggest Methodology to revise those technical things,to which you are not in touch at present, but you can write basic programs or have used 1-2 years ago. And also can U suggest some Quick revision links on Net for various technologies mentioned above.

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  • Render Ruby object to interactive html

    - by AvImd
    I am developing a tool that discovers network services enabled on host and writes short summary on them like this: init,1 +-- login,1560 -- +-- bash,1629 +-- nc,12137 -lup 50505 { :net = [ [0] "*:50505 IPv4 UDP " ], :fds = [ [0] "/root (cwd)", [1] "/", [2] "/bin/nc.traditional", [3] "/xochikit/ld_poison.so (stat: No such file or directory)", [4] "/dev/tty2", [5] "*:50505" ] } It proved to be very nice formatted and useful for quick discovery thanks to colors provided by the awesome_print gem. However, its output is just a text. One issue is that if I want to share it, I lose colors. I'd also like to fold and unfold parts of objects, quickly jump to specific processes and what not? Adding comments, for example. Thus I want something web-based. What is the best approach to implement features like these? I haven't worked with web interfaces before and I don't have much experience with Ruby.

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  • C++ difference between "char *" and "char * = new char[]"

    - by nashmaniac
    So, if I want to declare an array of characters I can go this way char a[2]; char * a ; char * a = new char[2]; Ignoring the first declaration, the other two use pointers. As far as I know the third declaration is stored in heap and is freed using the delete operator . does the second declaration also hold the array in heap ? Does it mean that if something is stored in heap and not freed can be used anywhere in a file like a variable with file linkage ? I tried both third and second declaration in one function and then using the variable in another but it didn't work, why ? Are there any other differences between the second and third declarations ?

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  • Why can't we capture the design of software more effectively?

    - by Ira Baxter
    As engineers, we all "design" artifacts (buildings, programs, circuits, molecules...). That's an activity (design-the-verb) that produces some kind of result (design-the-noun). I think we all agree that design-the-noun is a different entity than the artifact itself. A key activity in the software business (indeed, in any business where the resulting product artifact needs to be enhanced) is to understand the "design (the-noun)". Yet we seem, as a community, to be pretty much complete failures at recording it, as evidenced by the amount of effort people put into rediscovering facts about their code base. Ask somebody to show you the design of their code and see what you get. I think of a design for software as having: An explicit specification for what the software is supposed to do and how well it does it An explicit version of the code (this part is easy, everybody has it) An explanation for how each part of the code serves to achieve the specification A rationale as to why the code is the way it is (e.g., why a particualr choice rather than another) What is NOT a design is a particular perspective on the code. For example [not to pick specifically on] UML diagrams are not designs. Rather, they are properties you can derive from the code, or arguably, properties you wish you could derive from the code. But as a general rule, you can't derive the code from UML. Why is it that after 50+ years of building software, why don't we have regular ways to express this? My personal opinion is that we don't have good ways to express this. Even if we do, most of the community seems so focused on getting "code" that design-the-noun gets lost anyway. (IMHO, until design becomes the purpose of engineering, with the artifact extracted from the design, we're not going to get around this). What have you seen as means for recording designs (in the sense I have described it)? Explicit references to papers would be good. Why do you think specific and general means have not been succesful? How can we change this?

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  • What are the canonical problem sets or problem domains for the different types of languages?

    - by SnOrfus
    I'm just wondering what some of the canonical problem sets are for certain types of languages? ie. Fill in the blanks: __ is the perfect language to use for solving __. The question was arrived at reading or hearing people say statements like such and such module in our codebase would be much easier to implement using a functional language. Fee free to include examples that would seem obvious to you.

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  • Bitbucket and a small development house

    - by Marlon
    I am in the process of finally rolling Mercurial as our version control system at work. This is a huge deal for everyone as, shockingly, they have never used a VCS. After months of putting the bug in management's ears, they finally saw the light and now realise how much better it is than working with a network of shared folders! In the process of rolling this out, I am thinking of different strategies to manage our stuff and I am leaning towards using Bitbucket as our "central" repository. The projects in Bitbucket will solely be private projects and everyone will push and pull from there. I am open to different suggestions, but has anyone got a similar setup? If so, what caveats have you encountered?

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  • TDD - Outside In vs Inside Out

    - by Songo
    What is the difference between building an application Outside In vs building it Inside Out using TDD? These are the books I read about TDD and unit testing: Test Driven Development: By Example Test-Driven Development: A Practical Guide: A Practical Guide Real-World Solutions for Developing High-Quality PHP Frameworks and Applications Test-Driven Development in Microsoft .NET xUnit Test Patterns: Refactoring Test Code The Art of Unit Testing: With Examples in .Net Growing Object-Oriented Software, Guided by Tests---This one was really hard to understand since JAVA isn't my primary language :) Almost all of them explained TDD basics and unit testing in general, but with little mention of the different ways the application can be constructed. Another thing I noticed is that most of these books (if not all) ignore the design phase when writing the application. They focus more on writing the test cases quickly and letting the design emerge by itself. However, I came across a paragraph in xUnit Test Patterns that discussed the ways people approach TDD. There are 2 schools out there Outside In vs Inside Out. Sadly the book doesn't elaborate more on this point. I wish to know what is the main difference between these 2 cases. When should I use each one of them? To a TDD beginner which one is easier to grasp? What is the drawbacks of each method? Is there any materials out there that discuss this topic specifically?

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  • Can I use a project code which has New BSD license but uses a GPL license library?

    - by Alok Kulkarni
    I want to use the ICSOpenVpn project source code in my commercial application. If we see the ICSOpenVpn project, it states that its license is New BSD but the libopenvpn.so library it uses is under GNU GPLv2 license. As per FAQ for version 2 of GNU GPL "If a library is released under the GPL (not the LGPL), does that mean that any program which uses it has to be under the GPL?" The answer says: "Yes, because the program as it is actually run includes the library." Also, how could ICSOpenVpn change the license to New BSD?

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  • Books or help on OO Analysis

    - by Pat
    I have this course where we learn about the domain model, use cases, contracts and eventually leap into class diagrams and sequence diagrams to define good software classes. I just had an exam and I got trashed, but part of the reason is we barely have any practical material, I spent at least two good months without drawing a single class diagram by myself from a case study. I'm not here to blame the system or the class I'm in, I'm just wondering if people have some exercise-style books that either provide domain models with glossaries, system sequence diagrams and ask you to use GRASP to make software classes? I could really use some alone-time practicing going from analysis to conception of software entities. I'm almost done with Larman's book called "Applying UML and Patterns An Introduction to Object-Oriented Analysis and Design and Iterative Development, Third Edition". It's a good book, but I'm not doing anything by myself since it doesn't come with exercises. Thanks.

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  • Caching strategies for entities and collections

    - by Rob West
    We currently have an application framework in which we automatically cache both entities and collections of entities at the business layer (using .NET cache). So the method GetWidget(int id) checks the cache using a key GetWidget_Id_{0} before hitting the database, and the method GetWidgetsByStatusId(int statusId) checks the cache using GetWidgets_Collections_ByStatusId_{0}. If the objects are not in the cache they are retrieved from the database and added to the cache. This approach is obviously quick for read scenarios, and as a blanket approach is quick for us to implement, but requires large numbers of cache keys to be purged when CRUD operations are carried out on entities. Obviously as additional methods are added this impacts performance and the benefits of caching diminish. I'm interested in alternative approaches to handling caching of collections. I know that NHibernate caches a list of the identifiers in the collection rather than the actual entities. Is this an approach other people have tried - what are the pros and cons? In particular I am looking for options that optimise performance and can be implemented automatically through boilerplate generated code (we have our own code generation tool). I know some people will say that caching needs to be done by hand each time to meet the needs of the specific situation but I am looking for something that will get us most of the way automatically.

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  • Session state provider and atomic operations

    - by vtortola
    Hi, I've been thinking about this and it is blowing my mind... How does a session state provider properly works internally? I mean, I tried to write a custom session state provider based on Azure Tables or Blobs, but quickly I realized that because there is no way to ensure an atomic operation or establish a lock, race conditions are suitable to happen when several web servers do operation on that shared information. I know that there is a SQL Server Session State Provider (SQLS-SSP) and people is happy with it, so I guess that it's using some kind of transaction isolation level in order to accomplish some degree of concurrent safety, like checking is the data is lock (a simple column), locking it if not and returning the data in an atomic operation, but is that so? what does happen if the data is lock? does it returns an error? block the call for a while? returns it in read-only fashion? Cloud computing paradigms could be somehow new, but webfarms have been here for a while, so as I'm pretty new on it... do you recommend any good lecture about the topic? Thanks.

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  • How to send credentials to linkedIn website and get oauth_verifier without signing in again [closed]

    - by akash kumar
    I am facing a problem sending credentials to another website so that I can login the user (automatically, not clicked on sign in here) and get an oauth_verifier value. I want to send the email address and the password through a form (submit button) from my website (e.g. a Liferay portal) to another website (e.g. LinkedIn), so that it automatically returns an oauth_verifier to my website. That means I don't want the user of my website to submit his email and password to LinkedIn again. My goal is to take the email and password of the user in my website and show the user his LinkedIn connection, message, job posting (again, in my website, not LinkedIn). I dont want the user redirected to the LinkedIn website to sign in there and then come back to my website. I have taken a consumer key and a secret key from LinkedIn for my web aplication. I am using the LinkedIn API and getting oauth_verifier for access token but in order to login, I have to take user to LinkedIn to sign in, while I want it to happen in the backend.

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  • Developing professionally for both iOS, Android, web - an insight

    - by Scott Roberts
    This is not really a question on how to develop for both, I know various cross platform ways and so on. But I more want to know from developer standpoint how hard it is to basically develop iOS, Android and web apps? I am currently in my first job as a mobile/web developer. I have already developed my first iPhone/iPad app and now I have to develop the app for android because the web version I tried just didn't perform as well as needed and web databases just did not seem to make the cut. But I am not sure it's possible to be good at developing all 3 in terms of remembering all the api's etc. I wouldn't say I have an issue with the programming languages just how to use the api's for the various platforms. Also, all the other languages I look at, in my spare time, just feel like I am spreading myself to thin. Is it feasible for one person to be developing ios, android and web apps? Should I think about reducing it to iOS and web based apps? I develop everything by myself, so I have no one to discuss what the best solutions are for everything and I am just trying to workout as I go along. So any cross platform developers out there? Do companies have different teams for different platforms? Any insight would just help me get my head together. Hopefully this question makes sense.

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  • eBook editions of programming books

    - by Jon Hopkins
    (I'll get my justification for why this is on topic in early: programming books tend to have fairly specific formatting needs - code samples, tables, images and graphs - which are not common to all book types and are not necessarily well handled by eBook readers. Similarly they're used in different ways - you often dip in and out rather than read cover to cover.) I've just noticed that Don't Make Me Think by Steve Krug is available as an eBook edition for the Kindle (and presumably also for other readers) which set me thinking. There are certain advantages to eBook readers for tech books - primarily that you can carry a massive library of what would be heavy physical books around very easily. The downside is that certain eBook readers allegedly aren't particularly well equipped to cope with tables, code samples and so on and a book like Don't Make Me Think presumably makes extensive use of these sorts of things. So, the question, what are your experiences of reading and using programming books on an eBook reader and would you recommend it? I'm specifically interested in the latest generation Kindle but happy to hear about all devices - might be useful to state which one you use in the answer.

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  • I want to build a Virtual Machine, are there any good references?

    - by Michael Stum
    I'm looking to build a Virtual Machine as a platform independent way to run some game code (essentially scripting). The Virtual Machines that I'm aware of in games are rather old: Infocom's Z-Machine, LucasArts' SCUMM, id Software's Quake 3. As a .net Developer, I'm familiar with the CLR and looked into the CIL Instructions to get an overview of what you actually implement on a VM Level (vs. the language level). I've also dabbled a bit in 6502 Assembler during the last year. The thing is, now that I want¹ to implement one, I need to dig a bit deeper. I know that there are stack based and register based VMs, but I don't really know which one is better at what and if there are more or hybrid approaches. I need to deal with memory management, decide which low level types are part of the VM and need to understand why stuff like ldstr works the way it does. My only reference book (apart from the Z-Machine stuff) is the CLI Annotated Standard, but I wonder if there is a better, more general/fundamental lecture for VMs? Basically something like the Dragon Book, but for VMs? I'm aware of Donald Knuth's Art of Computer Programming which uses a register-based VM, but I'm not sure how applicable that series still is, especially since it's still unfinished? Clarification: The goal is to build a specialized VM. For example, Infocom's Z-Machine contains OpCodes for setting the Background Color or playing a sound. So I need to figure out how much goes into the VM as OpCodes vs. the compiler that takes a script (language TBD) and generates the bytecode from it, but for that I need to understand what I'm really doing. ¹ I know, modern technology would allow me to just interpret a high level scripting language on the fly. But where is the fun in that? :) It's also a bit hard to google because Virtual Machines is nowadays often associated with VMWare-type OS Virtualization...

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  • How to know which fields of a record are updated in saving the edit? [closed]

    - by Luiz Maffort
    I'm recording in a log table all that is changed in a given table, so this need to know when for example the User to change the status from active to inactive. With this information I will write in my log table information of which record was changed, by whom and what was the value of old and new. If I instantiate an object before: db.Entry(chamados).State = EntityState.Modified; I can even compare, but this error appears at runtime. *An object with the same key already exists in the ObjectStateManager. The ObjectStateManager cannot track multiple objects with the same key. * Podem me ajudar por favor?

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  • Finding co-maintainers for open source projects

    - by Mike Samuel
    I have a number of open-source projects that have gotten some significant usage and would like to find co-maintainers so that I am not a bottleneck when it comes to maintenance and support requests and to get other perspectives on how the project should evolve. Where should I look for co-maintainers, what should I look for in a co-maintainer, and how should I go about bringing them up to speed on the code and maintainer responsibilities?

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  • How to avoid code duplication for a system which has logic that may change year wise?

    - by aravind
    What would be the way to design a system which has logic that may change year wise? There is an application which conducts online exams. There are five questions for a particular subject. The questions may (or may not) change year wise. As per my current design, the questions in database are stored year wise. There are some year specific code logic as well. In order to enable the application for another year, the year specific database records and code will be copied or duplicated. How to avoid this code duplication?

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  • How and why are operating systems bootable from a USB?

    - by user114638
    I'm told to install ubuntu on my laptop for work in order to learn shell scripting. I've read the best way is to install ubuntu on a USB stick and partition my HDD. I'm curious how an OS is bootable from a USB stick? Is it literally just a small interface that can be put anywhere? This reminds me of a time I downloaded a game onto my USB stick, when I brought it to my friends house he told me it will run slow if I don't install it and only run it from the usb, is this different from running ubuntu from a usb? Will ubuntu be slow?

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  • Should my colleagues review each others code from source control system?

    - by Daniel Excinsky
    Hi everybody. So that's my story: one of my colleagues uses to review all the code, hosted to revision system. I'm not speaking about adequate review of changes in parts that he belongs to. He watches the code file to file, line to line. Every new file and every modified. I feel just like being spied on! My guess is that if code was already hosted to control system, you should trust it as workable at least. My question is, maybe I'm just too paranoiac and practice of reviewing each others code is good? P.S: We're team of only three developers, and I fear that if there will be more of us, colleague just won't have time to review all the the code we'll write.

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  • Any valid reason to Nest Master Pages in ASP.Net rather than Inherit?

    - by James P. Wright
    Currently in a debate at work and I cannot fathom why someone would intentionally avoid Inheritance with Master Pages. For reference here is the project setup: BaseProject MainMasterPage SomeEvent SiteProject SiteMasterPage nested MainMasterPage OtherSiteProject MainMasterPage (from BaseProject) The debate came up because some code in BaseProject needs to know about "SomeEvent". With the setup above, the code in BaseProject needs to call this.Master.Master. That same code in BaseProject also applies to OtherSiteProject which is just accessed as this.Master. SiteMasterPage has no code differences, only HTML differences. If SiteMasterPage Inherits MainMasterPage rather than Nests it, then all code is valid as this.Master. Can anyone think of a reason why to use a Nested Master Page here instead of an Inherited one?

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