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  • Run serveral daemon using python

    - by ylc
    I noticed that serveral daemon invoked python seperately. For example, I have both wicd and ibus daemon running on my machine. Instead of launching a single instance of python, the daemons run with two python instance at the same time in htop: /usr/bin/python2 -O /usr/share/wicd/daemon/monitor.py python2 /usr/share/ibus/ui/gtk/main.py Is it a waste of doing that? If yes, how can I improve this? If no, why avoid putting all daemons run on a single python instance?

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  • How to configure Amazon Security Groups to achieve multi-tier architecture?

    - by ks78
    What is the preferred way to configure Amazon Security Groups to achieve a multi-tier architecture? Each of my instances has its own Security Group, which I only want to use for rules specific to an instance. I'd like to keep any rules which apply to multiple instances in a separate Security Group, which can then be assigned to instance Security Groups as necessary. As an example, I've setup a group called "admin", which allows administrative access from my IP. I added the "admin" group as the source to each of my instance security groups. However, I still can't access the instances from my IP without adding the rules directly to the instance's group. Am I missing something? Although it seems a multi-tier security architecture should be possible, it doesn't seem to be working.

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  • Connection String Incorrectly Formatted [migrated]

    - by Randy E
    I'm running into some issues. Every time I launch into debug mode and hit the "Create User" button, I'm getting an exception being thrown that is due to the Connection String either being in the wrong syntax or just wrong. Using Visual Studio 2010, project is .NET 3.5 with SQL 2008 Express. This is just a personal project that I'm testing some other things with, I know this generally isn't the recommended format but for a personal small project, I don't see the point in doing it any other way. The things I'm testing actually work :) Data Source=.\SQLEXPRESS;AttachDbFilename=|Data Directory|ASPAppDatabase.mdf;Integrated Security=True;User Instance=True That doesn't work. Data Source=.\SQLEXPRESS;AttachDbFilename="|Data Directory|ASPAppDatabase.mdf";Integrated Security=True;User Instance=True Neither does that. Data Source=.\SQLEXPRESS;AttachDbFilename='|Data Directory|ASPAppDatabase.mdf';Integrated Security=True;User Instance=True And again, neither does that :/ However, rather than using "|Data directory| if I use the full path to the local DB file it works just fine and no exception is thrown, and I can read and write as I need. And just to cover all my bases, here is the button click event that creates the User. protected void btnAddUser_Click(object sender, EventArgs e) { Membership.CreateUser(txtUserName.Text, txtPassword.Text); btnLogin_Click(sender, e); } So, what am I missing in regards to the |Data Directory|? Here is an example of the above not working correctly..taken directly from web.config. <add name="ASPAppDatabaseConnection" connectionString='Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|ASPAppDatabase.mdf;Integrated Security=True;User Instance=True'/>

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  • Error running Solr

    - by Jon H
    I'm trying to install Apache Solr for Plone, via collective.solr. I've followed the instructions above, and extended my buildout with: [buildout] extends = buildout.cfg https://github.com/Jarn/collective.solr/raw/master/buildout/solr.cfg [instance] eggs += collective.solr bin/buildout runs fine, however, when I try bin/solr-instance fg I get the following error: Traceback (most recent call last): File "bin/solr-instance", line 114, in <module> start(False) File "bin/solr-instance", line 43, in start stdout=logfp, stderr=logfp).pid File "/usr/lib/python2.6/subprocess.py", line 633, in __init__ errread, errwrite) File "/usr/lib/python2.6/subprocess.py", line 1139, in _execute_child raise child_exception OSError: [Errno 2] No such file or directory Graceful stop What am I missing / doing wrong?

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  • Unable to SSH to a virtualbox Redhat

    - by Rajat
    I am using a MAC and using virtualbox to start a Redhat instance. The instance is started with two adapters (first being NAT, and second being host-only-adapter). The problem is that I am unable to SSH from my Mac to the virtualbox instance using the IP (I am able to ping the IP, though). I checked in the iptables and SSH is allowed (port 22), and sshd daemon is also running. Anything I am missing?

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  • How to Architect a system on AWS for scaling (with a MySQL back-end)

    - by Edan Maor
    I'm trying to understand how to architect an Amazon Web Services application. As I understand it, the whole point of using something like AWS is to make the eventual scaling easier, so I'm trying to understand how to do that. I have an instance, running off of EBS (EBS-based instance, not a regular instance). My application (a Django app) uses MySQL as a back-end. So the question is, where am I supposed to install the MySQL? Do I install it on the same instance? In which case, as far as I can tell, I can't simply create more server instances from that image. Or am I supposed to simply spin up another server as a DB server, and run off of that? Thanks for any help!

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  • MS SQL server: Single or multiple instances?

    - by Hugo Riley
    How costly (CPU or memory wise) is it to have multiple instances of SQL server 2005 instead of only one instance with prefixed databases? A company have three application providers. They each will install one application and they each require two or three databases. Should they all use the same instance or should every provider use it's own named instance? Is there any strong reason for one or other setup?

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  • Separation of memory oriented process and CPU oriented process

    - by Jeevan Dongre
    I am develops guy working for an e-commerce company I am running my e-commerce application built using ruby on rails spree commerce. I am presently running 2 medium instances in the production. One is a high memory instance which has 3.8 RAM and single Core CPU and another one is high CPU instance which has Dual Core CPU. Basically AWS calls it has m1.medium and c1.medium instance respectively. My question is it possible to separate the processes according the cpu intense and memory intense? So that all the cpu intense process can be made run in high cpu instance and all the memory intense process can be made to run in the high memory instances. Is any tool available to identify those process. Kindly give me some heads up. Thank you

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  • Integrating Amazon EC2 in Java via NetBeans IDE

    - by Geertjan
    Next, having looked at Amazon Associates services and Amazon S3, let's take a look at Amazon EC2, the elastic compute cloud which provides remote computing services. I started by launching an instance of Ubuntu Server 14.04 on Amazon EC2, which looks a bit like this in the on-line AWS Management Console, though I whitened out most of the details: Now that I have at least one running instance available on Amazon EC2, it makes sense to use the services that are integrated into NetBeans IDE:  I created a new application with one class, named "AmazonEC2Demo". Then I dragged the "describeInstances" service that you see above, with the mouse, into the class. Then the IDE automatically created all the other files you see below, i.e., 4 Java classes and one properties file: In the properties file, register the access ID and secret keys. These are read by the other generated Java classes. Signing and authentication are done automatically by the code that is generated, i.e., there's nothing generic you need to do and you can immediately begin working on your domain-specific code. Finally, you're now able to rewrite the code in "AmazonEC2Demo" to connect to Amazon EC2 and obtain information about your running instance: public class AmazonEC2Demo { public static void main(String[] args) { String instanceId1 = "i-something"; RestResponse result; try { result = AmazonEC2Service.describeInstances(instanceId1); System.out.println(result.getDataAsString()); } catch (IOException ex) { Logger.getLogger(AmazonEC2Demo.class.getName()).log(Level.SEVERE, null, ex); } } } From the above, you'll receive a chunk of XML with data about the running instance, it's name, status, dates, etc. In other words, you're now ready to integrate Amazon EC2 features directly into the applications you're writing, without very much work to get started. Within about 5 minutes, you're working on your business logic, rather than on the generic code that anyone needs when integrating with Amazon EC2.

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  • VPC SSH port forward into private subnet

    - by CP510
    Ok, so I've been racking my brain for DAYS on this dilema. I have a VPC setup with a public subnet, and a private subnet. The NAT is in place of course. I can connect from SSH into a instance in the public subnet, as well as the NAT. I can even ssh connect to the private instance from the public instance. I changed the SSHD configuration on the private instance to accept both port 22 and an arbitrary port number 1300. That works fine. But I need to set it up so that I can connect to the private instance directly using the 1300 port number, ie. ssh -i keyfile.pem [email protected] -p 1300 and 1.2.3.4 should route it to the internal server 10.10.10.10. Now I heard iptables is the job for this, so I went ahead and researched and played around with some routing with that. These are the rules I have setup on the public instance (not the NAT). I didn't want to use the NAT for this since AWS apperantly pre-configures the NAT instances when you set them up and I heard using iptables can mess that up. *filter :INPUT ACCEPT [129:12186] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [84:10472] -A INPUT -i lo -j ACCEPT -A INPUT -i eth0 -p tcp -m state --state NEW -m tcp --dport 1300 -j ACCEPT -A INPUT -d 10.10.10.10/32 -p tcp -m limit --limit 5/min -j LOG --log-prefix "SSH Dropped: " -A FORWARD -d 10.10.10.10/32 -p tcp -m tcp --dport 1300 -j ACCEPT -A OUTPUT -o lo -j ACCEPT COMMIT # Completed on Wed Apr 17 04:19:29 2013 # Generated by iptables-save v1.4.12 on Wed Apr 17 04:19:29 2013 *nat :PREROUTING ACCEPT [2:104] :INPUT ACCEPT [2:104] :OUTPUT ACCEPT [6:681] :POSTROUTING ACCEPT [7:745] -A PREROUTING -i eth0 -p tcp -m tcp --dport 1300 -j DNAT --to-destination 10.10.10.10:1300 -A POSTROUTING -p tcp -m tcp --dport 1300 -j MASQUERADE COMMIT So when I try this from home. It just times out. No connection refused messages or anything. And I can't seem to find any log messages about dropped packets. My security groups and ACL settings allow communications on these ports in both directions in both subnets and on the NAT. I'm at a loss. What am I doing wrong?

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  • Repairing a TFS 2005 install or starting anew.

    - by Johan Buret
    Following : Installing Team Foundation Server on a shared database instance We did use a shared database instance setup for TFS 2005, and that was not a good idea, because of the Reporting Service dependency. The reporting instance on the server gives error code 404. What works now Basic source code control. We're able to check in and out source code. What doesn't work : Everything else, including : Opening and creating new team projects. Build automation. Internal bug tracking. Goal setup Having a fully working TFS install, and keeping the history. 1) A full install of TFS 2005 on the same server, but within its own database and reporting instance. 2) Using another server might be an option, but it's really not prefered Downtime should be minimum, my colleagues needs to be able to work on the source Readings I've read the MSDN page about moving/restoring TFS 2005, but I'm still unsure about what to do. Thanks in advance for help

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  • Amazon EC2 open ports for security groups present in other accounts

    - by rahul
    Hi, Assume, I am having 2 ec2 accounts (say A and B), both have different list of security groups. Now I want to open a particular port (say 80) for an instance running in account A, to account B. ie, I want to only allow account B instances, to access account A's 80 port. Could any one update me, is there a way to do this.?? Additionally, may I access account A's instance from account B's instance by using its private ip address/host name ?? Thanks in Advance,

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  • pointers to member functions in an event dispatcher

    - by derivative
    For the past few days I've been trying to come up with a robust event handling system for the game (using a component based entity system, C++, OpenGL) I've been toying with. class EventDispatcher { typedef void (*CallbackFunction)(Event* event); typedef std::unordered_map<TypeInfo, std::list<CallbackFunction>, hash_TypeInfo > TypeCallbacksMap; EventQueue* global_queue_; TypeCallbacksMap callbacks_; ... } global_queue_ is a pointer to a wrapper EventQueue of std::queue<Event*> where Event is a pure virtual class. For every type of event I want to handle, I create a new derived class of Event, e.g. SetPositionEvent. TypeInfo is a wrapper on type_info. When I initialize my data, I bind functions to events in an unordered_map using TypeInfo(typeid(Event)) as the key that corresponds to a std::list of function pointers. When an event is dispatched, I iterate over the list calling the functions on that event. Those functions then static_cast the event pointer to the actual event type, so the event dispatcher needs to know very little. The actual functions that are being bound are functions for my component managers. For instance, SetPositionEvent would be handled by void PositionManager::HandleSetPositionEvent(Event* event) { SetPositionEvent* s_p_event = static_cast<SetPositionEvent*>(event); ... } The problem I'm running into is that to store a pointer to this function, it has to be static (or so everything leads me to believe.) In a perfect world, I want to store pointers member functions of a component manager that is defined in a script or whatever. It looks like I can store the instance of the component manager as well, but the typedef for this function is no longer simple and I can't find an example of how to do it. Is there a way to store a pointer to a member function of a class (along with a class instance, or, I guess a pointer to a class instance)? Is there an easier way to address this problem?

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  • What's better for deploying a website + DB on EC2: 2 small VM or a large one?

    - by devguy
    I'm planning the deployment of a mid-sized website with a SQL Server Standard DB. I've chosen Amazon EC2 to deploy it. I now have to choose between these 2 options: 1) get 2 small instances (1 core each, 1.7 GB of ram each): one for the IIS front-end, one for running the DB. Note: these "small instances" can only run the 32-bit version of Win2008 Server 2) a single large instance (4 cores, 7.5 gb of ram) where I'd install both IIS and the SQL Server. Note: this large instance can only run the 64-bit version of Win2008 Server What's better in terms on performance, scalability, ease of management (launch up a new instance while I backup the principal instance) etc. All suggestions and points of view are welcome!

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  • Pass User Data to AWS client

    - by bearrito
    Has anyone successful passed user data to the AWS CLI ? I have tried various incantations of the following but it does not work. Docs say string must be base64 encoded : http://docs.aws.amazon.com/cli/latest/reference/ec2/run-instances.html The instance logs never indicate the script is executed and chef is installed. aws ec2 run-instances --image-id ami-a73264ce --count 1 --instance-type t1.micro --key-name scrubbed --iam-instance-profile Arn=arn:aws:iam::scrubbed:instance-profile/scrubbed --user-data $(base64 chef_user_data.sh --wrap=0) chef_user_data.sh #!/bin/bash curl -L https://www.opscode.com/chef/install.sh | sudo bash

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  • Windows Server 2003 Is there a limit on number of TCP connections per process?

    - by aceinthehole
    We are running into issues with BizTalk host instance intermittently going down. One of the things that we are worried about is the number of FTP connections a single host instance is making which could easily reach into the hundreds perhaps sometimes thousands, depending on traffic. My question is Windows Server 2003 Is there a limit on number of TCP connections per process? If so would putting each application in it's own host instance potentially solve the problem.

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  • Advice for an EC2 Architecture and Deployment Strategy

    - by Mark
    My company is currently migrating several websites and PHP web applications (standard LAMP stack) from three in-house servers to Amazon EC2. Because we had only three servers, we clustered several low-traffic websites with perhaps one high-traffic web application, and served them from the same server. The server admin has pretty much copied the previous architecture wholesale onto the EC2 instances, simply upping the instance size to account for the highest traffic client that occupies that particular instance. This architecture might be okay if it wasn't for deployment. Any time one of these sites/apps changes, it means redeploying the entire instance, along with the 30 sites/apps it hosts, instead of just updating one. How can we architect our cloud in a more modular fashion? Should each app get its own appropriately-sized instance? What is the best strategy for deployment in this type of situation?

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  • Ubuntu package question

    - by Industrial
    Hi everyone, I run Ubuntu, and If i type the following in a terminal, I start a new instance of memcached, right? # memcached -vv How can I target the the current instance of memcached in terminal? It would help me to see the very-verbose mode on my already running instance. Thanks

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  • getting database connectivity issue from only one part of my ASP.net project?

    - by Greg
    Hi, Something weird has started happening to my project with Dynamic Data. Suddenly I am now getting connection errors when going to the DD navigation pages, but things work fine on the default DD main page, and also other MVC pages I've added in myself work fine to the database. Any ideas? So in summary if I go to the following web pages: custom URL for my custom controller - this works fine, including getting database data main DD page from root URL - this works fine click on a link to a table maintenance page from the main DD page - GET DATABASE CONNECTIVITY ERROR Some items: * I'm using SQL Server Express 2008 * Doesn't seem to be any debug/error info in VS2010 at all I can see * Web config entry: <add name="Model1Container" connectionString="metadata=res://*/Model1.csdl|res://*/Model1.ssdl|res://*/Model1.msl;provider=System.Data.SqlClient;provider connection string=&quot;Data Source=GREG\SQLEXPRESS_2008;Initial Catalog=greg_development;Integrated Security=True;MultipleActiveResultSets=True&quot;" providerName="System.Data.EntityClient"/> Error: Server Error in '/' Application. A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified) Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Data.SqlClient.SqlException: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified) Source Error: Line 39: DropDownList1.Items.Add(new ListItem("[Not Set]", NullValueString)); Line 40: } Line 41: PopulateListControl(DropDownList1); Line 42: // Set the initial value if there is one Line 43: string initialValue = DefaultValue; Source File: U:\My Dropbox\source\ToplogyLibrary\Topology_Web_Dynamic\DynamicData\Filters\ForeignKey.ascx.cs Line: 41 Stack Trace: [SqlException (0x80131904): A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)] System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection) +5009598 System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning() +234 System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity) +341 System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, Boolean ignoreSniOpenTimeout, TimeoutTimer timeout, SqlConnection owningObject) +129 System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(ServerInfo serverInfo, String newPassword, Boolean redirectedUserInstance, SqlConnection owningObject, SqlConnectionString connectionOptions, TimeoutTimer timeout) +239 System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(SqlConnection owningObject, TimeoutTimer timeout, SqlConnectionString connectionOptions, String newPassword, Boolean redirectedUserInstance) +195 System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, Object providerInfo, String newPassword, SqlConnection owningObject, Boolean redirectedUserInstance) +232 System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection) +185 System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnection owningConnection, DbConnectionPool pool, DbConnectionOptions options) +33 System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject) +524 System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject) +66 System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject) +479 System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection) +108 System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory) +126 System.Data.SqlClient.SqlConnection.Open() +125 System.Data.EntityClient.EntityConnection.OpenStoreConnectionIf(Boolean openCondition, DbConnection storeConnectionToOpen, DbConnection originalConnection, String exceptionCode, String attemptedOperation, Boolean& closeStoreConnectionOnFailure) +52 [EntityException: The underlying provider failed on Open.] System.Data.EntityClient.EntityConnection.OpenStoreConnectionIf(Boolean openCondition, DbConnection storeConnectionToOpen, DbConnection originalConnection, String exceptionCode, String attemptedOperation, Boolean& closeStoreConnectionOnFailure) +161 System.Data.EntityClient.EntityConnection.Open() +98 System.Data.Objects.ObjectContext.EnsureConnection() +81 System.Data.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption) +46 System.Data.Objects.ObjectQuery`1.System.Collections.Generic.IEnumerable<T>.GetEnumerator() +44 System.Data.Objects.ObjectQuery`1.GetEnumeratorInternal() +36 System.Data.Objects.ObjectQuery.System.Collections.IEnumerable.GetEnumerator() +10 System.Web.DynamicData.Misc.FillListItemCollection(IMetaTable table, ListItemCollection listItemCollection) +50 System.Web.DynamicData.QueryableFilterUserControl.PopulateListControl(ListControl listControl) +85 Topology_Web_Dynamic.ForeignKeyFilter.Page_Init(Object sender, EventArgs e) in U:\My Dropbox\source\ToplogyLibrary\Topology_Web_Dynamic\DynamicData\Filters\ForeignKey.ascx.cs:41 System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +14 System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +35 System.Web.UI.Control.OnInit(EventArgs e) +91 System.Web.UI.UserControl.OnInit(EventArgs e) +83 System.Web.UI.Control.InitRecursive(Control namingContainer) +140 System.Web.UI.Control.AddedControl(Control control, Int32 index) +197 System.Web.UI.ControlCollection.Add(Control child) +79 System.Web.DynamicData.DynamicFilter.EnsureInit(IQueryableDataSource dataSource) +200 System.Web.DynamicData.QueryableFilterRepeater.<Page_InitComplete>b__1(DynamicFilter f) +11 System.Collections.Generic.List`1.ForEach(Action`1 action) +145 System.Web.DynamicData.QueryableFilterRepeater.Page_InitComplete(Object sender, EventArgs e) +607 System.EventHandler.Invoke(Object sender, EventArgs e) +0 System.Web.UI.Page.OnInitComplete(EventArgs e) +8871862 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +604 Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.1

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  • Compile time Meta-programming, with string literals.

    - by Hassan Syed
    I'm writing some code which could really do with some simple compile time metaprogramming. It is common practise to use empty-struct tags as compile time symbols. I need to decorate the tags with some run-time config elements. static variables seem the only way to go (to enable meta-programming), however static variables require global declarations. to side step this Scott Myers suggestion (from the third edition of Effective C++), about sequencing the initialization of static variables by declaring them inside a function instead of as class variables, came to mind. So I came up with the following code, my hypothesis is that it will let me have a compile-time symbols with string literals use-able at runtime. I'm not missing anything I hope. template<class Instance> class TheBestThing { public: void set_name(const char * name_in) { get_name() = std::string(name_in); } void set_fs_location(const char * fs_location_in) { get_fs_location() = std::string(fs_location_in); } std::string & get_fs_location() { static std::string fs_location; return fs_location; } std::string & get_name() { static std::string name; return name; } }; struct tag {}; int main() { TheBestThing<tag> x; x.set_name("xyz"); x.set_fs_location("/etc/lala"); ImportantObject<x> SinceSlicedBread; }

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  • Java Memory Model: reordering and concurrent locks

    - by Steffen Heil
    Hi The java meomry model mandates that synchronize blocks that synchronize on the same monitor enforce a before-after-realtion on the variables modified within those blocks. Example: // in thread A synchronized( lock ) { x = true; } // in thread B synchronized( lock ) { System.out.println( x ); } In this case it is garanteed that thread B will see x==true as long as thread A already passed that synchronized-block. Now I am in the process to rewrite lots of code to use the more flexible (and said to be faster) locks in java.util.concurrent, especially the ReentrantReadWriteLock. So the example looks like this: // in thread A synchronized( lock ) { lock.writeLock().lock(); x = true; lock.writeLock().unlock(); } // in thread B synchronized( lock ) { lock.readLock().lock(); System.out.println( x ); lock.readLock().unlock(); } However, I have not seen any hints within the memory model specification that such locks also imply the nessessary ordering. Looking into the implementation it seems to rely on the access to volatile variables inside AbstractQueuedSynchronizer (for the sun implementation at least). However this is not part of any specification and moreover access to non-volatile variables is not really condsidered covered by the memory barrier given by these variables, is it? So, here are my questions: Is it safe to assume the same ordering as with the "old" synchronized blocks? Is this documented somewhere? Is accessing any volatile variable a memory barrier for any other variable? Regards, Steffen

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  • How to implement Excel Solver functionality in C#?

    - by Vic
    Hi, I have an application in C#, I need to do some optimization calculations, like Excel Solver Add-in does, one option is certainly to write my own solver implementation, but I'm kind of short of time, so I'm looking into libraries that already exist that can help me with this. I've been trying the Microsoft Solver Foundation, which seems pretty neat and cool, the problem is that it doesn't seem to work with the kind of calculations that I need to do. At the end of this question I'm adding the information about the calculations I need to perform and optimize. So basically my question is if any of you know of any other library that I can use for this purpose, or any tutorial that can help to do my own solver, or any idea that gives me a lead to solve this issue. Thanks. Additional Info: This is the data I need to calculate: I have 7 variables, lets call them var1, var2,...,var7 The constraints for these variables are: All of them need to be 0 <= varn <= 0.5 (where n is the number of the variable) The sum of all the variables should be equal to 1 The objective is to maximize the target formula, which in Excel looks like this: (MMULT(TRANSPOSE(L26:L32),M14:M20)) / (SQRT(MMULT(MMULT(TRANSPOSE(L26:L32),M4:S10),L26:L32))) The range that you see in this formula, L26:L32, is actually the range with the variables from above, var1, var2,..., varn. M14:M20 and M4:S10 are ranges with data that I get from different sources, there are more likely decimal values. As I said before, I was using Microsoft Solver Foundation, I modeled pretty much everything with it, I created functions that handle the operations of the target formula, but when I tried to solve the model it always fail, I think it is because of the complexity of the operations. In any case, I just wanted to show these data so you can have an idea about the kind of calculations that I need to implement.

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  • Drop Down Box and other stuff in ASP.NET with VB.NET (VS 2008)

    - by typoknig
    Hi all, I am trying to polish up a program a program that I have converted from a Windows Form in to an ASP.NET Web Application. I have several questions: 1.) I have a drop down box where users can select their variables, but users can also enter their variables manually into various text fields. What I want is for the drop down box to show a string like "Choose Variables" when ever the user enters their variables manually. I want this to happen without having to reload the page. 2.) In the Windows Form version of this application I had a RichTextBox that populated with data (line by line) after a calculation was made. I used "AppendText" in my Windows Form, but that is not available in ASP.NET, and neither is the RichTextBox. I am open to suggestions here, I tried to use just a text box but that isn't working right. 3.) In my Windows Form application I was using "KeyPress" events to prevent incorrect characters from being entered into the text fields. My code for these events looked similar to this: Private Sub TextBox_KeyPress(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox.KeyPress If (e.KeyChar < "0" OrElse e.KeyChar > "9") AndAlso e.KeyChar <> ControlChars.Back AndAlso e.KeyChar <> "." Then e.Handled = True End If End Sub How can I make this work again... also without reloading the page. 4.) This is not a major issue, but I would like all of the text to be selected when the cursor enters a field. In my Windows Form application I used "SelectAll", but again, that is not available in ASP.NET Thanks in advanced.

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  • Javascript scope chain

    - by Geromey
    Hi, I am trying to optimize my program. I think I understand the basics of closure. I am confused about the scope chain though. I know that in general you want a low scope (to access variables quickly). Say I have the following object: var my_object = (function(){ //private variables var a_private = 0; return{ //public //public variables a_public : 1, //public methods some_public : function(){ debugger; alert(this.a_public); alert(a_private); }; }; })(); My understanding is that if I am in the some_public method I can access the private variables faster than the public ones. Is this correct? My confusion comes with the scope level of this. When the code is stopped at debugger, firebug shows the public variable inside the this keyword. The this word is not inside a scope level. How fast is accessing this? Right now I am storing any this.properties as another local variable to avoid accessing it multiple times. Thanks very much!

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  • How to set up django-admin.py on windos vista?

    - by shin
    I manage to install Django after some struggles by using setup.py install on Windows Vista Now I tried to use django-admin.py but it is not working. According to this document, http://docs.djangoproject.com/en/dev/ref/django-admin/ The django-admin.py script should be on your system path if you installed Django via its setup.py utility. If it’s not on your path, ... For Windows users, who do not have symlinking functionality available, you can copy django-admin.py to a location on your existing path or edit the PATH settings (under Settings - Control Panel - System - Advanced - Environment...) to point to its installed location. I checked ComputerpropertiesEnvironment Variables, but path to django-admin.py is not in anywhere. So I added C:\Python25\Lib\site-packages\django\bin which is the folder of django-admin.py in User variables for shin Variable PATH, Value C:\Program Files\Google\google_appengine\;C:\Python25\Lib\site-packages\django\bin\ Am I supposed to add to System variables?? But it still does not work. Could anyone tell me how to add the Path in Environment Variables please? Thanks in advance.

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