Search Results

Search found 9094 results on 364 pages for 'dynamic entities'.

Page 138/364 | < Previous Page | 134 135 136 137 138 139 140 141 142 143 144 145  | Next Page >

  • How could you parallelise a 2D boids simulation

    - by Sycren
    How could you program a 2D boids simulation in such a way that it could use processing power from different sources (clusters, gpu). In the above example, the non-coloured particles move around until they cluster (yellow) and stop moving. The problem is that all the entities could potentially interact with each other although an entity in the top left is unlikely to interact with one in the bottom right. If the domain was split into different segments, it may speed the whole thing up, But if an entity wanted to cross into another segment there may be problems. At the moment this simulation works with 5000 entities with a good frame rate, I would like to try this with millions if possible. Would it be possible to use quad trees to further optimise this? Any other suggestions?

    Read the article

  • Cisco ASA (Client VPN) to LAN - through second VPN to second LAN

    - by user50855
    We have 2 site that is linked by an IPSEC VPN to remote Cisco ASAs: Site 1 1.5Mb T1 Connection Cisco(1) 2841 Site 2 1.5Mb T1 Connection Cisco 2841 In addition: Site 1 has a 2nd WAN 3Mb bonded T1 Connection Cisco 5510 that connects to same LAN as Cisco(1) 2841. Basically, Remote Access (VPN) users connecting through Cisco ASA 5510 needs access to a service at the end of Site 2. This is due to the way the service is sold - Cisco 2841 routers are not under our management and it is setup to allow connection from local LAN VLAN 1 IP address 10.20.0.0/24. My idea is to have all traffic from Remote Users through Cisco ASA destined for Site 2 to go via the VPN between Site 1 and Site 2. The end result being all traffic that hits Site 2 has come via Site 1. I'm struggling to find a great deal of information on how this is setup. So, firstly, can anyone confirm that what I'm trying to achieve is possible? Secondly, can anyone help me to correct the configuration bellow or point me in the direction of an example of such a configuration? Many Thanks. interface Ethernet0/0 nameif outside security-level 0 ip address 7.7.7.19 255.255.255.240 interface Ethernet0/1 nameif inside security-level 100 ip address 10.20.0.249 255.255.255.0 object-group network group-inside-vpnclient description All inside networks accessible to vpn clients network-object 10.20.0.0 255.255.255.0 network-object 10.20.1.0 255.255.255.0 object-group network group-adp-network description ADP IP Address or network accessible to vpn clients network-object 207.207.207.173 255.255.255.255 access-list outside_access_in extended permit icmp any any echo-reply access-list outside_access_in extended permit icmp any any source-quench access-list outside_access_in extended permit icmp any any unreachable access-list outside_access_in extended permit icmp any any time-exceeded access-list outside_access_in extended permit tcp any host 7.7.7.20 eq smtp access-list outside_access_in extended permit tcp any host 7.7.7.20 eq https access-list outside_access_in extended permit tcp any host 7.7.7.20 eq pop3 access-list outside_access_in extended permit tcp any host 7.7.7.20 eq www access-list outside_access_in extended permit tcp any host 7.7.7.21 eq www access-list outside_access_in extended permit tcp any host 7.7.7.21 eq https access-list outside_access_in extended permit tcp any host 7.7.7.21 eq 5721 access-list acl-vpnclient extended permit ip object-group group-inside-vpnclient any access-list acl-vpnclient extended permit ip object-group group-inside-vpnclient object-group group-adp-network access-list acl-vpnclient extended permit ip object-group group-adp-network object-group group-inside-vpnclient access-list PinesFLVPNTunnel_splitTunnelAcl standard permit 10.20.0.0 255.255.255.0 access-list inside_nat0_outbound_1 extended permit ip 10.20.0.0 255.255.255.0 10.20.1.0 255.255.255.0 access-list inside_nat0_outbound_1 extended permit ip 10.20.0.0 255.255.255.0 host 207.207.207.173 access-list inside_nat0_outbound_1 extended permit ip 10.20.1.0 255.255.255.0 host 207.207.207.173 ip local pool VPNPool 10.20.1.100-10.20.1.200 mask 255.255.255.0 route outside 0.0.0.0 0.0.0.0 7.7.7.17 1 route inside 207.207.207.173 255.255.255.255 10.20.0.3 1 crypto ipsec transform-set ESP-3DES-SHA esp-3des esp-sha-hmac crypto ipsec security-association lifetime seconds 28800 crypto ipsec security-association lifetime kilobytes 4608000 crypto dynamic-map outside_dyn_map 20 set transform-set ESP-3DES-SHA crypto dynamic-map outside_dyn_map 20 set security-association lifetime seconds 288000 crypto dynamic-map outside_dyn_map 20 set security-association lifetime kilobytes 4608000 crypto dynamic-map outside_dyn_map 20 set reverse-route crypto map outside_map 20 ipsec-isakmp dynamic outside_dyn_map crypto map outside_map interface outside crypto map outside_dyn_map 20 match address acl-vpnclient crypto map outside_dyn_map 20 set security-association lifetime seconds 28800 crypto map outside_dyn_map 20 set security-association lifetime kilobytes 4608000 crypto isakmp identity address crypto isakmp enable outside crypto isakmp policy 20 authentication pre-share encryption 3des hash sha group 2 lifetime 86400 group-policy YeahRightflVPNTunnel internal group-policy YeahRightflVPNTunnel attributes wins-server value 10.20.0.9 dns-server value 10.20.0.9 vpn-tunnel-protocol IPSec password-storage disable pfs disable split-tunnel-policy tunnelspecified split-tunnel-network-list value acl-vpnclient default-domain value YeahRight.com group-policy YeahRightFLVPNTunnel internal group-policy YeahRightFLVPNTunnel attributes wins-server value 10.20.0.9 dns-server value 10.20.0.9 10.20.0.7 vpn-tunnel-protocol IPSec split-tunnel-policy tunnelspecified split-tunnel-network-list value YeahRightFLVPNTunnel_splitTunnelAcl default-domain value yeahright.com tunnel-group YeahRightFLVPN type remote-access tunnel-group YeahRightFLVPN general-attributes address-pool VPNPool tunnel-group YeahRightFLVPNTunnel type remote-access tunnel-group YeahRightFLVPNTunnel general-attributes address-pool VPNPool authentication-server-group WinRadius default-group-policy YeahRightFLVPNTunnel tunnel-group YeahRightFLVPNTunnel ipsec-attributes pre-shared-key *

    Read the article

  • C# 4.0: COM Interop Improvements

    - by Paulo Morgado
    Dynamic resolution as well as named and optional arguments greatly improve the experience of interoperating with COM APIs such as Office Automation Primary Interop Assemblies (PIAs). But, in order to alleviate even more COM Interop development, a few COM-specific features were also added to C# 4.0. Ommiting ref Because of a different programming model, many COM APIs contain a lot of reference parameters. These parameters are typically not meant to mutate a passed-in argument, but are simply another way of passing value parameters. Specifically for COM methods, the compiler allows to declare the method call passing the arguments by value and will automatically generate the necessary temporary variables to hold the values in order to pass them by reference and will discard their values after the call returns. From the point of view of the programmer, the arguments are being passed by value. This method call: object fileName = "Test.docx"; object missing = Missing.Value; document.SaveAs(ref fileName, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing); can now be written like this: document.SaveAs("Test.docx", Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value); And because all parameters that are receiving the Missing.Value value have that value as its default value, the declaration of the method call can even be reduced to this: document.SaveAs("Test.docx"); Dynamic Import Many COM methods accept and return variant types, which are represented in the PIAs as object. In the vast majority of cases, a programmer calling these methods already knows the static type of a returned object form the context of the call, but has to explicitly perform a cast on the returned values to make use of that knowledge. These casts are so common that they constitute a major nuisance. To make the developer’s life easier, it is now possible to import the COM APIs in such a way that variants are instead represented using the type dynamic which means that COM signatures have now occurrences of dynamic instead of object. This means that members of a returned object can now be easily accessed or assigned into a strongly typed variable without having to cast. Instead of this code: ((Excel.Range)(excel.Cells[1, 1])).Value2 = "Hello World!"; this code can now be used: excel.Cells[1, 1] = "Hello World!"; And instead of this: Excel.Range range = (Excel.Range)(excel.Cells[1, 1]); this can be used: Excel.Range range = excel.Cells[1, 1]; Indexed And Default Properties A few COM interface features are still not available in C#. On the top of the list are indexed properties and default properties. As mentioned above, these will be possible if the COM interface is accessed dynamically, but will not be recognized by statically typed C# code. No PIAs – Type Equivalence And Type Embedding For assemblies indentified with PrimaryInteropAssemblyAttribute, the compiler will create equivalent types (interfaces, structs, enumerations and delegates) and embed them in the generated assembly. To reduce the final size of the generated assembly, only the used types and their used members will be generated and embedded. Although this makes development and deployment of applications using the COM components easier because there’s no need to deploy the PIAs, COM component developers are still required to build the PIAs.

    Read the article

  • The Evolution Of C#

    - by Paulo Morgado
    The first release of C# (C# 1.0) was all about building a new language for managed code that appealed, mostly, to C++ and Java programmers. The second release (C# 2.0) was mostly about adding what wasn’t time to built into the 1.0 release. The main feature for this release was Generics. The third release (C# 3.0) was all about reducing the impedance mismatch between general purpose programming languages and databases. To achieve this goal, several functional programming features were added to the language and LINQ was born. Going forward, new trends are showing up in the industry and modern programming languages need to be more: Declarative With imperative languages, although having the eye on the what, programs need to focus on the how. This leads to over specification of the solution to the problem in hand, making next to impossible to the execution engine to be smart about the execution of the program and optimize it to run it more efficiently (given the hardware available, for example). Declarative languages, on the other hand, focus only on the what and leave the how to the execution engine. LINQ made C# more declarative by using higher level constructs like orderby and group by that give the execution engine a much better chance of optimizing the execution (by parallelizing it, for example). Concurrent Concurrency is hard and needs to be thought about and it’s very hard to shoehorn it into a programming language. Parallel.For (from the parallel extensions) looks like a parallel for because enough expressiveness has been built into C# 3.0 to allow this without having to commit to specific language syntax. Dynamic There was been lots of debate on which ones are the better programming languages: static or dynamic. The fact is that both have good qualities and users of both types of languages want to have it all. All these trends require a paradigm switch. C# is, in many ways, already a multi-paradigm language. It’s still very object oriented (class oriented as some might say) but it can be argued that C# 3.0 has become a functional programming language because it has all the cornerstones of what a functional programming language needs. Moving forward, will have even more. Besides the influence of these trends, there was a decision of co-evolution of the C# and Visual Basic programming languages. Since its inception, there was been some effort to position C# and Visual Basic against each other and to try to explain what should be done with each language or what kind of programmers use one or the other. Each language should be chosen based on the past experience and familiarity of the developer/team/project/company and not by particular features. In the past, every time a feature was added to one language, the users of the other wanted that feature too. Going forward, when a feature is added to one language, the other will work hard to add the same feature. This doesn’t mean that XML literals will be added to C# (because almost the same can be achieved with LINQ To XML), but Visual Basic will have auto-implemented properties. Most of these features require or are built on top of features of the .NET Framework and, the focus for C# 4.0 was on dynamic programming. Not just dynamic types but being able to talk with anything that isn’t a .NET class. Also introduced in C# 4.0 is co-variance and contra-variance for generic interfaces and delegates. Stay tuned for more on the new C# 4.0 features.

    Read the article

  • Creating Entity as an aggregation

    - by Jamie Dixon
    I recently asked about how to separate entities from their behaviour and the main answer linked to this article: http://cowboyprogramming.com/2007/01/05/evolve-your-heirachy/ The ultimate concept written about here is that of: OBJECT AS A PURE AGGREGATION. I'm wondering how I might go about creating game entities as pure aggregation using C#. I've not quite grasped the concept of how this might work yet. (Perhaps the entity is an array of objects implementing a certain interface or base type?) My current thinking still involves having a concrete class for each entity type that then implements the relevant interfaces (IMoveable, ICollectable, ISpeakable etc). How can I go about creating an entity purely as an aggregation without having any concrete type for that entity?

    Read the article

  • Entity Framework Batch Update and Future Queries

    - by pwelter34
    Entity Framework Extended Library A library the extends the functionality of Entity Framework. Features Batch Update and Delete Future Queries Audit Log Project Package and Source NuGet Package PM> Install-Package EntityFramework.Extended NuGet: http://nuget.org/List/Packages/EntityFramework.Extended Source: http://github.com/loresoft/EntityFramework.Extended Batch Update and Delete A current limitations of the Entity Framework is that in order to update or delete an entity you have to first retrieve it into memory. Now in most scenarios this is just fine. There are however some senerios where performance would suffer. Also, for single deletes, the object must be retrieved before it can be deleted requiring two calls to the database. Batch update and delete eliminates the need to retrieve and load an entity before modifying it. Deleting //delete all users where FirstName matches context.Users.Delete(u => u.FirstName == "firstname"); Update //update all tasks with status of 1 to status of 2 context.Tasks.Update( t => t.StatusId == 1, t => new Task {StatusId = 2}); //example of using an IQueryable as the filter for the update var users = context.Users .Where(u => u.FirstName == "firstname"); context.Users.Update( users, u => new User {FirstName = "newfirstname"}); Future Queries Build up a list of queries for the data that you need and the first time any of the results are accessed, all the data will retrieved in one round trip to the database server. Reducing the number of trips to the database is a great. Using this feature is as simple as appending .Future() to the end of your queries. To use the Future Queries, make sure to import the EntityFramework.Extensions namespace. Future queries are created with the following extension methods... Future() FutureFirstOrDefault() FutureCount() Sample // build up queries var q1 = db.Users .Where(t => t.EmailAddress == "[email protected]") .Future(); var q2 = db.Tasks .Where(t => t.Summary == "Test") .Future(); // this triggers the loading of all the future queries var users = q1.ToList(); In the example above, there are 2 queries built up, as soon as one of the queries is enumerated, it triggers the batch load of both queries. // base query var q = db.Tasks.Where(t => t.Priority == 2); // get total count var q1 = q.FutureCount(); // get page var q2 = q.Skip(pageIndex).Take(pageSize).Future(); // triggers execute as a batch int total = q1.Value; var tasks = q2.ToList(); In this example, we have a common senerio where you want to page a list of tasks. In order for the GUI to setup the paging control, you need a total count. With Future, we can batch together the queries to get all the data in one database call. Future queries work by creating the appropriate IFutureQuery object that keeps the IQuerable. The IFutureQuery object is then stored in IFutureContext.FutureQueries list. Then, when one of the IFutureQuery objects is enumerated, it calls back to IFutureContext.ExecuteFutureQueries() via the LoadAction delegate. ExecuteFutureQueries builds a batch query from all the stored IFutureQuery objects. Finally, all the IFutureQuery objects are updated with the results from the query. Audit Log The Audit Log feature will capture the changes to entities anytime they are submitted to the database. The Audit Log captures only the entities that are changed and only the properties on those entities that were changed. The before and after values are recorded. AuditLogger.LastAudit is where this information is held and there is a ToXml() method that makes it easy to turn the AuditLog into xml for easy storage. The AuditLog can be customized via attributes on the entities or via a Fluent Configuration API. Fluent Configuration // config audit when your application is starting up... var auditConfiguration = AuditConfiguration.Default; auditConfiguration.IncludeRelationships = true; auditConfiguration.LoadRelationships = true; auditConfiguration.DefaultAuditable = true; // customize the audit for Task entity auditConfiguration.IsAuditable<Task>() .NotAudited(t => t.TaskExtended) .FormatWith(t => t.Status, v => FormatStatus(v)); // set the display member when status is a foreign key auditConfiguration.IsAuditable<Status>() .DisplayMember(t => t.Name); Create an Audit Log var db = new TrackerContext(); var audit = db.BeginAudit(); // make some updates ... db.SaveChanges(); var log = audit.LastLog;

    Read the article

  • Adding Attributes to Generated Classes

    ASP.NET MVC 2 adds support for data annotations, implemented via attributes on your model classes.  Depending on your design, you may be using an OR/M tool like Entity Framework or LINQ-to-SQL to generate your entity classes, and you may further be using these entities directly as your Model.  This is fairly common, and alleviates the need to do mapping between POCO domain objects and such entities (though there are certainly pros and cons to using such entities directly). As an example, the current version of the NerdDinner application (available on CodePlex at nerddinner.codeplex.com) uses Entity Framework for its model.  Thus, there is a NerdDinner.edmx file in the project, and a generated NerdDinner.Models.Dinner class.  Fortunately, these generated classes are marked as partial, so you can extend their behavior via your own partial class in a separate file.  However, if for instance the generated Dinner class has a property Title of type string, you cant then add your own Title of type string for the purpose of adding data annotations to it, like this: public partial class Dinner { [Required] public string Title { get;set; } } This will result in a compilation error, because the generated Dinner class already contains a definition of Title.  How then can we add attributes to this generated code?  Do we need to go into the T4 template and add a special case that says if were generated a Dinner class and it has a Title property, add this attribute?  Ick. MetadataType to the Rescue The MetadataType attribute can be used to define a type which contains attributes (metadata) for a given class.  It is applied to the class you want to add metadata to (Dinner), and it refers to a totally separate class to which youre free to add whatever methods and properties you like.  Using this attribute, our partial Dinner class might look like this: [MetadataType(typeof(Dinner_Validation))] public partial class Dinner {}   public class Dinner_Validation { [Required] public string Title { get; set; } } In this case the Dinner_Validation class is public, but if you were concerned about muddying your API with such classes, it could instead have been created as a private class within Dinner.  Having the validation attributes specified in their own class (with no other responsibilities) complies with the Single Responsibility Principle and makes it easy for you to test that the validation rules you expect are in place via these annotations/attributes. Thanks to Julie Lerman for her help with this.  Right after she showed me how to do this, I realized it was also already being done in the project I was working on. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

    Read the article

  • Cooperator Framework

    - by csharp-source.net
    Cooperator Framework is a base class library for high performance Object Relational Mapping (ORM), and a code generation tool that aids agile application development for Microsoft .Net Framework 2.0/3.0. The main features are: * Use business entities. * Full typed Model (Data Layer and Entities) * Maintain persistence across the layers by passing specific types( .net 2.0/3.0 generics) * Business objects can bind to controls in Windows Forms and Web Forms taking advantage of data binding of Visual Studio 2005. * Supports any Primary Key defined on tables, with no need to modify it or to create a unique field. * Uses stored procedures for data access. * Supports concurrency. * Generates code both for stored procedures and projects in C# or Visual Basic. * Maintains the model in a repository, which can be modified in any stage of the development cycle, regenerating the model on demand.

    Read the article

  • Code Reuse is (Damn) Hard

    - by James Michael Hare
    Being a development team lead, the task of interviewing new candidates was part of my job.  Like any typical interview, we started with some easy questions to get them warmed up and help calm their nerves before hitting the hard stuff. One of those easier questions was almost always: “Name some benefits of object-oriented development.”  Nearly every time, the candidate would chime in with a plethora of canned answers which typically included: “it helps ease code reuse.”  Of course, this is a gross oversimplification.  Tools only ease reuse, its developers that ultimately can cause code to be reusable or not, regardless of the language or methodology. But it did get me thinking…  we always used to say that as part of our mantra as to why Object-Oriented Programming was so great.  With polymorphism, inheritance, encapsulation, etc. we in essence set up the concepts to help facilitate reuse as much as possible.  And yes, as a developer now of many years, I unquestionably held that belief for ages before it really struck me how my views on reuse have jaded over the years.  In fact, in many ways Agile rightly eschews reuse as taking a backseat to developing what's needed for the here and now.  It used to be I was in complete opposition to that view, but more and more I've come to see the logic in it.  Too many times I've seen developers (myself included) get lost in design paralysis trying to come up with the perfect abstraction that would stand all time.  Nearly without fail, all of these pieces of code become obsolete in a matter of months or years. It’s not that I don’t like reuse – it’s just that reuse is hard.  In fact, reuse is DAMN hard.  Many times it is just a distraction that eats up architect and developer time, and worse yet can be counter-productive and force wrong decisions.  Now don’t get me wrong, I love the idea of reusable code when it makes sense.  These are in the few cases where you are designing something that is inherently reusable.  The problem is, most business-class code is inherently unfit for reuse! Furthermore, the code that is reusable will often fail to be reused if you don’t have the proper framework in place for effective reuse that includes standardized versioning, building, releasing, and documenting the components.  That should always be standard across the board when promoting reusable code.  All of this is hard, and it should only be done when you have code that is truly reusable or you will be exerting a large amount of development effort for very little bang for your buck. But my goal here is not to get into how to reuse (that is a topic unto itself) but what should be reused.  First, let’s look at an extension method.  There’s many times where I want to kick off a thread to handle a task, then when I want to reign that thread in of course I want to do a Join on it.  But what if I only want to wait a limited amount of time and then Abort?  Well, I could of course write that logic out by hand each time, but it seemed like a great extension method: 1: public static class ThreadExtensions 2: { 3: public static bool JoinOrAbort(this Thread thread, TimeSpan timeToWait) 4: { 5: bool isJoined = false; 6:  7: if (thread != null) 8: { 9: isJoined = thread.Join(timeToWait); 10:  11: if (!isJoined) 12: { 13: thread.Abort(); 14: } 15: } 16: return isJoined; 17: } 18: } 19:  When I look at this code, I can immediately see things that jump out at me as reasons why this code is very reusable.  Some of them are standard OO principles, and some are kind-of home grown litmus tests: Single Responsibility Principle (SRP) – The only reason this extension method need change is if the Thread class itself changes (one responsibility). Stable Dependencies Principle (SDP) – This method only depends on classes that are more stable than it is (System.Threading.Thread), and in itself is very stable, hence other classes may safely depend on it. It is also not dependent on any business domain, and thus isn't subject to changes as the business itself changes. Open-Closed Principle (OCP) – This class is inherently closed to change. Small and Stable Problem Domain – This method only cares about System.Threading.Thread. All-or-None Usage – A user of a reusable class should want the functionality of that class, not parts of that functionality.  That’s not to say they most use every method, but they shouldn’t be using a method just to get half of its result. Cost of Reuse vs. Cost to Recreate – since this class is highly stable and minimally complex, we can offer it up for reuse very cheaply by promoting it as “ready-to-go” and already unit tested (important!) and available through a standard release cycle (very important!). Okay, all seems good there, now lets look at an entity and DAO.  I don’t know about you all, but there have been times I’ve been in organizations that get the grand idea that all DAOs and entities should be standardized and shared.  While this may work for small or static organizations, it’s near ludicrous for anything large or volatile. 1: namespace Shared.Entities 2: { 3: public class Account 4: { 5: public int Id { get; set; } 6:  7: public string Name { get; set; } 8:  9: public Address HomeAddress { get; set; } 10:  11: public int Age { get; set;} 12:  13: public DateTime LastUsed { get; set; } 14:  15: // etc, etc, etc... 16: } 17: } 18:  19: ... 20:  21: namespace Shared.DataAccess 22: { 23: public class AccountDao 24: { 25: public Account FindAccount(int id) 26: { 27: // dao logic to query and return account 28: } 29:  30: ... 31:  32: } 33: } Now to be fair, I’m not saying there doesn’t exist an organization where some entites may be extremely static and unchanging.  But at best such entities and DAOs will be problematic cases of reuse.  Let’s examine those same tests: Single Responsibility Principle (SRP) – The reasons to change for these classes will be strongly dependent on what the definition of the account is which can change over time and may have multiple influences depending on the number of systems an account can cover. Stable Dependencies Principle (SDP) – This method depends on the data model beneath itself which also is largely dependent on the business definition of an account which can be very inherently unstable. Open-Closed Principle (OCP) – This class is not really closed for modification.  Every time the account definition may change, you’d need to modify this class. Small and Stable Problem Domain – The definition of an account is inherently unstable and in fact may be very large.  What if you are designing a system that aggregates account information from several sources? All-or-None Usage – What if your view of the account encompasses data from 3 different sources but you only care about one of those sources or one piece of data?  Should you have to take the hit of looking up all the other data?  On the other hand, should you have ten different methods returning portions of data in chunks people tend to ask for?  Neither is really a great solution. Cost of Reuse vs. Cost to Recreate – DAOs are really trivial to rewrite, and unless your definition of an account is EXTREMELY stable, the cost to promote, support, and release a reusable account entity and DAO are usually far higher than the cost to recreate as needed. It’s no accident that my case for reuse was a utility class and my case for non-reuse was an entity/DAO.  In general, the smaller and more stable an abstraction is, the higher its level of reuse.  When I became the lead of the Shared Components Committee at my workplace, one of the original goals we looked at satisfying was to find (or create), version, release, and promote a shared library of common utility classes, frameworks, and data access objects.  Now, of course, many of you will point to nHibernate and Entity for the latter, but we were looking at larger, macro collections of data that span multiple data sources of varying types (databases, web services, etc). As we got deeper and deeper in the details of how to manage and release these items, it quickly became apparent that while the case for reuse was typically a slam dunk for utilities and frameworks, the data access objects just didn’t “smell” right.  We ended up having session after session of design meetings to try and find the right way to share these data access components. When someone asked me why it was taking so long to iron out the shared entities, my response was quite simple, “Reuse is hard...”  And that’s when I realized, that while reuse is an awesome goal and we should strive to make code maintainable, often times you end up creating far more work for yourself than necessary by trying to force code to be reusable that inherently isn’t. Think about classes the times you’ve worked in a company where in the design session people fight over the best way to implement a class to make it maximally reusable, extensible, and any other buzzwordable.  Then think about how quickly that design became obsolete.  Many times I set out to do a project and think, “yes, this is the best design, I can extend it easily!” only to find out the business requirements change COMPLETELY in such a way that the design is rendered invalid.  Code, in general, tends to rust and age over time.  As such, writing reusable code can often be difficult and many times ends up being a futile exercise and worse yet, sometimes makes the code harder to maintain because it obfuscates the design in the name of extensibility or reusability. So what do I think are reusable components? Generic Utility classes – these tend to be small classes that assist in a task and have no business context whatsoever. Implementation Abstraction Frameworks – home-grown frameworks that try to isolate changes to third party products you may be depending on (like writing a messaging abstraction layer for publishing/subscribing that is independent of whether you use JMS, MSMQ, etc). Simplification and Uniformity Frameworks – To some extent this is similar to an abstraction framework, but there may be one chosen provider but a development shop mandate to perform certain complex items in a certain way.  Or, perhaps to simplify and dumb-down a complex task for the average developer (such as implementing a particular development-shop’s method of encryption). And what are less reusable? Application and Business Layers – tend to fluctuate a lot as requirements change and new features are added, so tend to be an unstable dependency.  May be reused across applications but also very volatile. Entities and Data Access Layers – these tend to be tuned to the scope of the application, so reusing them can be hard unless the abstract is very stable. So what’s the big lesson?  Reuse is hard.  In fact it’s damn hard.  And much of the time I’m not convinced we should focus too hard on it. If you’re designing a utility or framework, then by all means design it for reuse.  But you most also really set down a good versioning, release, and documentation process to maximize your chances.  For anything else, design it to be maintainable and extendable, but don’t waste the effort on reusability for something that most likely will be obsolete in a year or two anyway.

    Read the article

  • What are graphs in laymen's terms

    - by Justin984
    What are graphs, in computer science, and what are they used for? In laymen's terms preferably. I have read the definition on Wikipedia: In computer science, a graph is an abstract data type that is meant to implement the graph and hypergraph concepts from mathematics. A graph data structure consists of a finite (and possibly mutable) set of ordered pairs, called edges or arcs, of certain entities called nodes or vertices. As in mathematics, an edge (x,y) is said to point or go from x to y. The nodes may be part of the graph structure, or may be external entities represented by integer indices or references. but I'm looking for a less formal, easier to understand definition.

    Read the article

  • Scripting for a C#, multiplayer game

    - by Vaughan Hilts
    I have a multiplayer game written in C# and we've recently been creating a lot of content but have been looking for a way to give our entities customization logic that the designers can hook into. I took a look at this post. With something like this in mind (using C# as a scripting language); I have a few questions. 1) Would one embed the script itself in the entity object before persisting to it to the disk? Is this okay? 2) Would I compile once per scripting then - this seems like a lot of overhead to store all these compiled Assemblies to execute. Any general advice on how to do thigns is welcome, too. These entities are generated on the fly inside the editor and could be composed of a lot of different things.

    Read the article

  • How can I test if my rotated rectangle intersects a corner?

    - by Raven Dreamer
    I have a square, tile-based collision map. To check if one of my (square) entities is colliding, I get the vertices of the 4 corners, and test those 4 points against my collision map. If none of those points are intersecting, I know I'm good to move to the new position. I'd like to allow entities to rotate. I can still calculate the 4 corners of the square, but once you factor in rotation, those 4 corners alone don't seem to be enough information to determine if the entity is trying to move to a valid state. For example: In the picture below, black is unwalkable terrain, and red is the player's hitbox. The left scenario is allowed because the 4 corners of the red square are not in the black terrain. The right scenario would also be (incorrectly) allowed, because the player, cleverly turned at a 45* angle, has its corners in valid spaces, even if it is (quite literally) cutting the corner. How can I detect scenarios similar to the situation on the right?

    Read the article

  • Where do service implementations fit into the Microsoft Application Architecture guidelines?

    - by tuespetre
    The guidelines discuss the service layer with its service interfaces and data/message/fault contracts. They also discuss the business layer with its logic/workflow components and entities as well as the 'optional' application facade. What is unclear still to me after studying this guide is where the implementations of the service interfaces belong. Does the application facade in the business layer implement these interfaces, or does a separate 'service facade' exist to make calls to the business layer and it's facade/raw components? (With the former, there would be less seemingly trivial calls to yet another layer, though with the latter I could see how the service layer could remove the concerns of translating business entities to data contracts from the business layer.)

    Read the article

  • Software Architecture and MEF composition location

    - by Leonardo
    Introduction My software (a bunch of webapi's) consist of 4 projects: Core, FrontWebApi, Library and Administration. Library is a code library project that consists of only interfaces and enumerators. All my classes in other projects inherit from at least one interface, and this interface is in the library. Generally speaking, my interfaces define either Entities, Repositories or Controllers. This project references no other project or any special dlls... just the regular .Net stuff... Core is a class-library project where concrete implementation of Entities and Repositories. In some cases i have more than 1 implementation for a Repository (ex: one for azure table storage and one for regular Sql). This project handles the intelligence (business rules mostly) and persistence, and it references only the Library. FrontWebApi is a ASP.NET MVC 4 WebApi project that implements the controllers interfaces to handle web-requests (from a mobile native app)... It references the Core and the Library. Administration is a code-library project that represents a "optional-module", meaning: if it is present, it provides extra-features (such as Access Control Lists) to the application, but if its not, no problem. Administration is also only referencing the Library and implementing concrete classes of a few interfaces such as "IAccessControlEntry"... I intend to make this available with a "setup" that will create any required database table or anything like that. But it is important to notice that the Core has no reference to this project... Development Now, in order to have a decoupled code I decide to use IoC and because this is a small project, I decided to do it using MEF, specially because of its advertised "composition" capabilities. I arranged all the imports/exports and constructors and everything, but something is quite not perfect in my "mental-visualisation": Main Question Where should I "Compose" the objects? I mean: Technically, the only place where real implementation access is required is in the Repositories, because in order to retrieve data from wherever, entities instances will be necessary, and in all other places. The repositories could also provide a public "GetCleanInstanceOf()" right? Then all other places will be just fine working with the interfaces instead of concrete classes... Secondary Question Should "Administration" implement the concrete object for "IAccessControlGeneralRepository" or the Core should?

    Read the article

  • Has this server been compromised?

    - by Griffo
    A friend is running a VPS (CentOS) His business partner was the sysadmin but has left him high and dry to look after the system. So, I've been asked to help out in fixing an apparent spam problem. His IP address got blacklisted for unsolicited mail. I'm not sure where to look for a problem, but I started with netstat to see what open connections were running. It looks to me like he has remote hosts connected to his SMTP server. Here's the output: Active Internet connections (w/o servers) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 78.153.208.195:imap 86-40-60-183-dynamic.:10029 ESTABLISHED tcp 0 0 78.153.208.195:imap 86-40-60-183-dynamic.:10010 ESTABLISHED tcp 0 1 78.153.208.195:35563 news.avanport.pt:smtp SYN_SENT tcp 0 0 78.153.208.195:35559 vip-us-br-mx.terra.com:smtp TIME_WAIT tcp 0 0 78.153.208.195:35560 vip-us-br-mx.terra.com:smtp TIME_WAIT tcp 1 1 78.153.208.195:imaps 86-40-60-183-dynamic.:11647 CLOSING tcp 1 1 78.153.208.195:imaps 86-40-60-183-dynamic.:11645 CLOSING tcp 0 0 78.153.208.195:35562 mx.a.locaweb.com.br:smtp TIME_WAIT tcp 0 0 78.153.208.195:35561 mx.a.locaweb.com.br:smtp TIME_WAIT tcp 0 0 78.153.208.195:imap 86-41-8-64-dynamic.b-:49446 ESTABLISHED Does this indicate that his server may be acting as an open relay? Mail should only be outgoing from localhost. Apologies for my lack of knowledge but I don't work on linux in my day job. EDIT: Here's some output from /var/log/maillog which looks like it may be the result of spam. If it appears to be the case to others, where should I look next to investigate a root cause? I put the server IP through www.checkor.com and it came back clean. Jun 29 00:02:13 vps-1001108-595 qmail: 1309302133.721674 status: local 0/10 remote 9/20 Jun 29 00:02:13 vps-1001108-595 qmail: 1309302133.886182 delivery 74116: deferral: 200.147.36.15_does_not_like_recipient./Remote_host_said:_450_4.7.1_Client_host_rejected:_cannot_find_your_hostname,_[78.153.208.195]/Giving_up_on_200.147.36.15./ Jun 29 00:02:13 vps-1001108-595 qmail: 1309302133.886255 status: local 0/10 remote 8/20 Jun 29 00:02:13 vps-1001108-595 qmail: 1309302133.898266 delivery 74115: deferral: 187.31.0.11_does_not_like_recipient./Remote_host_said:_450_4.7.1_Client_host_rejected:_cannot_find_your_hostname,_[78.153.208.195]/Giving_up_on_187.31.0.11./ Jun 29 00:02:13 vps-1001108-595 qmail: 1309302133.898327 status: local 0/10 remote 7/20 Jun 29 00:02:14 vps-1001108-595 qmail: 1309302134.137833 delivery 74111: deferral: Sorry,_I_wasn't_able_to_establish_an_SMTP_connection._(#4.4.1)/ Jun 29 00:02:14 vps-1001108-595 qmail: 1309302134.137914 status: local 0/10 remote 6/20 Jun 29 00:02:19 vps-1001108-595 qmail: 1309302139.903536 delivery 74000: failure: 209.85.143.27_failed_after_I_sent_the_message./Remote_host_said:_550-5.7.1_[78.153.208.195_______1]_Our_system_has_detected_an_unusual_rate_of/550-5.7.1_unsolicited_mail_originating_from_your_IP_address._To_protect_our/550-5.7.1_users_from_spam,_mail_sent_from_your_IP_address_has_been_blocked./550-5.7.1_Please_visit_http://www.google.com/mail/help/bulk_mail.html_to_review/550_5.7.1_our_Bulk_Email_Senders_Guidelines._e25si1385223wes.137/ Jun 29 00:02:19 vps-1001108-595 qmail: 1309302139.903606 status: local 0/10 remote 5/20 Jun 29 00:02:19 vps-1001108-595 qmail-queue-handlers[15501]: Handlers Filter before-queue for qmail started ... EDIT #2 Here's the output of netstat -p with the imap and imaps lines removed. I also removed my own ssh session Active Internet connections (w/o servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 1 78.153.208.195:40076 any-in-2015.1e100.net:smtp SYN_SENT 24096/qmail-remote. tcp 0 1 78.153.208.195:40077 any-in-2015.1e100.net:smtp SYN_SENT 24097/qmail-remote. udp 0 0 78.153.208.195:48515 125.64.11.158:4225 ESTABLISHED 20435/httpd

    Read the article

  • Automatically zoom out the camera to show all players

    - by user36159
    I am building a game in XNA that takes place in a rectangular arena. The game is multiplayer and each player may go where they like within the arena. The camera is a perspective camera that looks directly downwards. The camera should be automatically repositioned based on the game state. Currently, the xy position is a weighted sum of the xy positions of important entities. I would like the camera's z position to be calculated from the xy coordinates so that it zooms out to the point where all important entities are visible. My current approach is to: hw = the greatest x distance from the camera to an important entity hh = the greatest y distance from the camera to an important entity Calculate z = max(hw / tan(FoVx), hh / tan(FoVy)) My code seems to almost work as it should, but the resulting z values are always too low by a factor of about 4. Any ideas?

    Read the article

  • Automatically zoom out the camera to show all players (XNA)

    - by user36159
    I am building a game in XNA that takes place in a rectangular arena. The game is multiplayer and each player may go where they like within the arena. The camera is a persepective camera that looks directly downwards. The camera should be automatically repositioned based on the game state. Currently, the xy position is a weighted sum of the xy positions of important entities. I would like the camera's z position to be calculated from the xy coordinates so that it zooms out to the point where all important entities are visible. My current approach is to: hw = the greatest x distance from the camera to an important entity hh = the greatest y distance from the camera to an important entity Calculate z = max(hw / tan(FoVx), hh / tan(FoVy)) My code seems to almost work as it should, but the resulting z values are always too low by a factor of about 4. Any ideas?

    Read the article

  • What are some high quality Enterprise Architecture conferences or training programs?

    - by Stimy
    I am looking for a conference or training which will give me a broad exposure to enterprise level software architecture. I've been with the same company for 10 years and we've grown to the size where we really need to lay out a framework for the applications which support our company's business. The organic growth over the last 10 years has left us with a tightly coupled and fairly messy set of applications. We need to do a better job at componentizing our business entities and have more rigorous control on the interfaces between those entities and our business processes. I'm looking to get a broad, yet practical exposure on design patterns to support that architecture (SOA, messaging, ESB's etc). I'm hoping to gain insight from folks who have direct experience with implementing or working with what would be considered an enterprise class architecture.

    Read the article

  • .Net Application & Database Modularity/Reuse

    - by Martaver
    I'm looking for some guidance on how to architect an app with regards to modularity, separation of concerns and re-usability. I'm working on an application (ASP.Net, C#) that has distinctly generic chunks of functionality, that I'd love to be able to lift out, all layers, into re-usable components. This means the module handles the database schema, data access, API, everything so that the next time I want to use it I can just register the module and hook into it. Developing modules of re-usable functionality is a no-brainer, but what is really confusing me is what to do when it comes to handling a core re-usable database schema that serves the module's functionality. In an ideal world, I would register a module and it would ensure that the associated database schema exists in the DB. I would code on the assumption that the tables exist, calling the module's functionality through the DLL, agnostic of the database layer. Kind of like Enterprise Library's Caching/Logging Application Block, which can create a DB schema in the target DB to use as a data store. My Questions is: What do you think is the best way to achieve this, firstly, in terms design architecture, and secondly solution structure. What patterns/frameworks do you know that exist & support this kind of thing? My thoughts so far: I mostly use Entity Framework and SQL Server DB Projects. I thought about a 'black box' approach to modules of functionality. I could use use a code-first approach in EF4, and use the ObjectContext to create a database when the module is initialized. However this means that all of the entities that my module encapsulates would be disconnected from the rest of the application because they belonged to an abstracted ObjectContext. Further - Creating appropriate indexes and references between domain entities and the module's entities would be impossible to do practically. I've thought of adopting Enterprise Library and creating my own Application Blocks. I'm not sure how this would play nice with Entity Framework (if at all) though. I like the idea of building on proven patterns & practices to encapsulate established, reusable functionality. I thought of abandoning Entity Framework for the Module, and just creating a separate DB schema for the module with its own set of stored procedures & ADO.Net. Then deploying the script at run-time if interrogation shows that it doesn't exist. But once again, for application developing outside of the application, I would want to use Entity Framework and I would have to use the module separately, disconnected from the domain ObjectContext. Has anyone had experience developing these sorts of full-stack modules? What advice can you offer? Am I biting off more than I can chew?

    Read the article

  • How granular should a command be in a CQ[R]S model?

    - by Aaronaught
    I'm considering a project to migrate part of our WCF-based SOA over to a service bus model (probably nServiceBus) and using some basic pub-sub to achieve Command-Query Separation. I'm not new to SOA, or even to service bus models, but I confess that until recently my concept of "separation" was limited to run-of-the-mill database mirroring and replication. Still, I'm attracted to the idea because it seems to provide all the benefits of an eventually-consistent system while sidestepping many of the obvious drawbacks (most notably the lack of proper transactional support). I've read a lot on the subject from Udi Dahan who is basically the guru on ESB architectures (at least in the Microsoft world), but one thing he says really puzzles me: As we get larger entities with more fields on them, we also get more actors working with those same entities, and the higher the likelihood that something will touch some attribute of them at any given time, increasing the number of concurrency conflicts. [...] A core element of CQRS is rethinking the design of the user interface to enable us to capture our users’ intent such that making a customer preferred is a different unit of work for the user than indicating that the customer has moved or that they’ve gotten married. Using an Excel-like UI for data changes doesn’t capture intent, as we saw above. -- Udi Dahan, Clarified CQRS From the perspective described in the quotation, it's hard to argue with that logic. But it seems to go against the grain with respect to SOAs. An SOA (and really services in general) are supposed to deal with coarse-grained messages so as to minimize network chatter - among many other benefits. I realize that network chatter is less of an issue when you've got highly-distributed systems with good message queuing and none of the baggage of RPC, but it doesn't seem wise to dismiss the issue entirely. Udi almost seems to be saying that every attribute change (i.e. field update) ought to be its own command, which is hard to imagine in the context of one user potentially updating hundreds or thousands of combined entities and attributes as it often is with a traditional web service. One batch update in SQL Server may take a fraction of a second given a good highly-parameterized query, table-valued parameter or bulk insert to a staging table; processing all of these updates one at a time is slow, slow, slow, and OLTP database hardware is the most expensive of all to scale up/out. Is there some way to reconcile these competing concerns? Am I thinking about it the wrong way? Does this problem have a well-known solution in the CQS/ESB world? If not, then how does one decide what the "right level" of granularity in a Command should be? Is there some "standard" one can use as a starting point - sort of like 3NF in databases - and only deviate when careful profiling suggests a potentially significant performance benefit? Or is this possibly one of those things that, despite several strong opinions being expressed by various experts, is really just a matter of opinion?

    Read the article

  • Seven Accounting Changes for 2010

    - by Theresa Hickman
    I read a very interesting article called Seven Accounting Changes That Will Affect Your 2010 Annual Report from SmartPros that nicely summarized how 2010 annual financial statements will be impacted.  Here’s a Reader’s Digest version of the changes: 1.  Changes to revenue recognition if you sell bundled products with multiple deliverables: Old Rule: You needed to objectively establish the “fair value” of each bundled item. So if you sold a dishwasher plus installation and could not establish the fair value of the installation, you might have to delay recognizing revenue of the dishwasher days or weeks later until it was installed. New Rule (ASU 2009-13): “Objective” proof of each service or good is no longer required; you can simply estimate the selling price of the installation and warranty. So the dishwasher vendor can recognize the dishwasher revenue immediately at the point of sale without waiting a few weeks for the installation. Then they can recognize the estimated value of the installation after it is complete. 2.  Changes to revenue recognition for devices with embedded software: Old Rule: Hardware devices with embedded software, such as the iPhone, had to follow stringent software revrec rules. This forced Apple to recognize iPhone revenues over two years, the period of time that software updates were provided. New Rule (ASU 2009-14): Software revrec rules no longer apply to these devices with embedded software; these devices can now follow ASU 2009-13. This allows vendors, such as Apple, to recognize revenue sooner. 3.  Fair value disclosures: Companies (both public and private) now need to spend extra time gathering, summarizing, and disclosing information about items measured at fair value, such as significant transfers in and out of Level 1(quoted market price), Level 2 (valuation based on observable markets), and Level 3 (valuations based on internal information). 4.  Consolidation of variable interest entities (a.k.a special purpose entities): Consolidation rules for variable interest entities now require a qualitative, not quantitative, analysis to determine the primary beneficiary. Instead of simply looking at the percentage of voting interests, the primary beneficiary could have less than the majority interests as long as it has the power to direct the activities and absorb any losses.  5.  XBRL: Starting in June 2011, all U.S. public companies are required to file financial statements to the SEC using XBRL. Note: Oracle supports XBRL reporting. 6.  Non-GAAP financial disclosures: Companies that report non-GAAP measures of performance, such as EBITDA in SEC filings, have more flexibility.  The new interpretations can be found here: http://www.sec.gov/divisions/corpfin/guidance/nongaapinterp.htm.  7.  Loss contingencies disclosures: Companies should expect additional scrutiny of their loss disclosures, such as those from litigation losses, in their annual financial statements. The SEC wants more disclosures about loss contingencies sooner instead of after the cases are settled.

    Read the article

  • How far should an entity take care of its properties values by itself?

    - by Kharlos Dominguez
    Let's consider the following example of a class, which is an entity that I'm using through Entity Framework. - InvoiceHeader - BilledAmount (property, decimal) - PaidAmount (property, decimal) - Balance (property, decimal) I'm trying to find the best approach to keep Balance updated, based on the values of the two other properties (BilledAmount and PaidAmount). I'm torn between two practices here: Updating the balance amount every time BilledAmount and PaidAmount are updated (through their setters) Having a UpdateBalance() method that the callers would run on the object when appropriate. I am aware that I can just calculate the Balance in its getter. However, it isn't really possible because this is an entity field that needs to be saved back to the database, where it has an actual column, and where the calculated amount should be persisted to. My other worry about the automatically updating approach is that the calculated values might be a little bit different from what was originally saved to the database, due to rounding values (an older version of the software, was using floats, but now decimals). So, loading, let's say 2000 entities from the database could change their status and make the ORM believe that they have changed and be persisted back to the database the next time the SaveChanges() method is called on the context. It would trigger a mass of updates that I am not really interested in, or could cause problems, if the calculation methods changed (the entities fetched would lose their old values to be replaced by freshly recalculated ones, simply by being loaded). Then, let's take the example even further. Each invoice has some related invoice details, which also have BilledAmount, PaidAmount and Balance (I'm simplifying my actual business case for the sake of the example, so let's assume the customer can pay each item of the invoice separately rather than as a whole). If we consider the entity should take care of itself, any change of the child details should cause the Invoice totals to change as well. In a fully automated approach, a simple implementation would be looping through each detail of the invoice to recalculate the header totals, every time one the property changes. It probably would be fine for just a record, but if a lot of entities were fetched at once, it could create a significant overhead, as it would perform this process every time a new invoice detail record is fetched. Possibly worse, if the details are not already loaded, it could cause the ORM to lazy-load them, just to recalculate the balances. So far, I went with the Update() method-way, mainly for the reasons I explained above, but I wonder if it was right. I'm noticing I have to keep calling these methods quite often and at different places in my code and it is potential source of bugs. It also has a detrimental effect on data-binding because when the properties of the detail or header changes, the other properties are left out of date and the method has no way to be called. What is the recommended approach in this case?

    Read the article

  • Increasing efficiency of N-Body gravity simulation

    - by Postman
    I'm making a space exploration type game, it will have many planets and other objects that will all have realistic gravity. I currently have a system in place that works, but if the number of planets goes above 70, the FPS decreases an practically exponential rates. I'm making it in C# and XNA. My guess is that I should be able to do gravity calculations between 100 objects without this kind of strain, so clearly my method is not as efficient as it should be. I have two files, Gravity.cs and EntityEngine.cs. Gravity manages JUST the gravity calculations, EntityEngine creates an instance of Gravity and runs it, along with other entity related methods. EntityEngine.cs public void Update() { foreach (KeyValuePair<string, Entity> e in Entities) { e.Value.Update(); } gravity.Update(); } (Only relevant piece of code from EntityEngine, self explanatory. When an instance of Gravity is made in entityEngine, it passes itself (this) into it, so that gravity can have access to entityEngine.Entities (a dictionary of all planet objects)) Gravity.cs namespace ExplorationEngine { public class Gravity { private EntityEngine entityEngine; private Vector2 Force; private Vector2 VecForce; private float distance; private float mult; public Gravity(EntityEngine e) { entityEngine = e; } public void Update() { //First loop foreach (KeyValuePair<string, Entity> e in entityEngine.Entities) { //Reset the force vector Force = new Vector2(); //Second loop foreach (KeyValuePair<string, Entity> e2 in entityEngine.Entities) { //Make sure the second value is not the current value from the first loop if (e2.Value != e.Value ) { //Find the distance between the two objects. Because Fg = G * ((M1 * M2) / r^2), using Vector2.Distance() and then squaring it //is pointless and inefficient because distance uses a sqrt, squaring the result simple cancels that sqrt. distance = Vector2.DistanceSquared(e2.Value.Position, e.Value.Position); //This makes sure that two planets do not attract eachother if they are touching, completely unnecessary when I add collision, //For now it just makes it so that the planets are not glitchy, performance is not significantly improved by removing this IF if (Math.Sqrt(distance) > (e.Value.Texture.Width / 2 + e2.Value.Texture.Width / 2)) { //Calculate the magnitude of Fg (I'm using my own gravitational constant (G) for the sake of time (I know it's 1 at the moment, but I've been changing it) mult = 1.0f * ((e.Value.Mass * e2.Value.Mass) / distance); //Calculate the direction of the force, simply subtracting the positions and normalizing works, this fixes diagonal vectors //from having a larger value, and basically makes VecForce a direction. VecForce = e2.Value.Position - e.Value.Position; VecForce.Normalize(); //Add the vector for each planet in the second loop to a force var. Force = Vector2.Add(Force, VecForce * mult); //I have tried Force += VecForce * mult, and have not noticed much of an increase in speed. } } } //Add that force to the first loop's planet's position (later on I'll instead add to acceleration, to account for inertia) e.Value.Position += Force; } } } } I have used various tips (about gravity optimizing, not threading) from THIS question (that I made yesterday). I've made this gravity method (Gravity.Update) as efficient as I know how to make it. This O(N^2) algorithm still seems to be eating up all of my CPU power though. Here is a LINK (google drive, go to File download, keep .Exe with the content folder, you will need XNA Framework 4.0 Redist. if you don't already have it) to the current version of my game. Left click makes a planet, right click removes the last planet. Mouse moves the camera, scroll wheel zooms in and out. Watch the FPS and Planet Count to see what I mean about performance issues past 70 planets. (ALL 70 planets must be moving, I've had 100 stationary planets and only 5 or so moving ones while still having 300 fps, the issue arises when 70+ are moving around) After 70 planets are made, performance tanks exponentially. With < 70 planets, I get 330 fps (I have it capped at 300). At 90 planets, the FPS is about 2, more than that and it sticks around at 0 FPS. Strangely enough, when all planets are stationary, the FPS climbs back up to around 300, but as soon as something moves, it goes right back down to what it was, I have no systems in place to make this happen, it just does. I considered multithreading, but that previous question I asked taught me a thing or two, and I see now that that's not a viable option. I've also thought maybe I could do the calculations on my GPU instead, though I don't think it should be necessary. I also do not know how to do this, it is not a simple concept and I want to avoid it unless someone knows a really noob friendly simple way to do it that will work for an n-body gravity calculation. (I have an NVidia gtx 660) Lastly I've considered using a quadtree type system. (Barnes Hut simulation) I've been told (in the previous question) that this is a good method that is commonly used, and it seems logical and straightforward, however the implementation is way over my head and I haven't found a good tutorial for C# yet that explains it in a way I can understand, or uses code I can eventually figure out. So my question is this: How can I make my gravity method more efficient, allowing me to use more than 100 objects (I can render 1000 planets with constant 300+ FPS without gravity calculations), and if I can't do much to improve performance (including some kind of quadtree system), could I use my GPU to do the calculations?

    Read the article

  • Retrieve data from an ASP.Net application using ADO.Net 2.0 connected model

    - by nikolaosk
    I have been teaching Entity Framework,LINQ to SQL,LINQ to objects,LINQ to XML for some time now. I am huge fan of LINQ to Entities and I am using Entity Framework as my main data access technology. Entity framework is in the second version right now and I can accomplish most of the things I need. I am sure the guys in the ADO.Net team will implement many more features in the future. I am a strong believer that you cannot really understand the benefits of LINQ to SQL or LINQ to Entities unless you...(read more)

    Read the article

  • Cost of Web Server that hosted and delivered text only

    - by slandau
    We are developing an application that needs a web server to interact with the two (or more) entities involved. They will not ever see anything on the web, but the server is required for the transfer of data between them. It's sort of a holding point. Now, the only thing the server is going to be holding is textual data. The two entities are going to be doing the work with the data. I was wondering what the cost of this type of server would be. Since it would be JUST a database with no front end, would it make sense to employ a service through Amazon or Google that just holds data for me to access instead of buying a server and making my own database? The amount of data can grow very large however it's only text, and all data over a day old will be deleted for the most part every day. Thanks!

    Read the article

< Previous Page | 134 135 136 137 138 139 140 141 142 143 144 145  | Next Page >