CODEWITHSUNDEEP
c#.netmatlab
cs0815
cs0815

Reputation: 17388

invoke matlab several times from .net

It seems to be impossible to invoke matlab several times:

[STAThread]
static void Main(string[] args)
{
    IList<DTO> LotsOfWork = new List<DTO>();
    // create some work
    for(int c = 0; c < 10; c++)
    {
    LotsOfWork.Add(new DTO(){ Id = c, Parameter1 = c, Parameter2 = c });
    }

    // deal with work
    foreach (DTO DTO in LotsOfWork)
    {
    MLApp.MLApp matlab = new MLApp.MLApp();
    object result;

    matlab.Execute("clear;");
    matlab.PutWorkspaceData("a", "base", DTO.Parameter1);
    matlab.PutWorkspaceData("b", "base", DTO.Parameter2);
    matlab.Execute("result = a + b;");
    matlab.GetWorkspaceData("result", "base", out result);
    }
}

public class DTO
{
    public int Id { get; set; }
    public double Parameter1 { get; set; }
    public double Parameter2 { get; set; }
    public string Result { get; set; }
}

The second loop iteration throws an exception:

at System.RuntimeType.ForwardCallToInvokeMember(String memberName, BindingFlags flags, Object target, Int32[] aWrapperTypes, MessageData& msgData)
at MLApp.DIMLApp.GetWorkspaceData(String Name, String Workspace, Object& pdata)
at Sandbox.Program.Main(String[] args) in C:\Bla\Program.cs:line 53
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()

I am also wondering whether it is possible to run something like this 'threaded' (i.e. spawn off a thread for each DTO object). Thanks.

Upvotes: 0

Views: 813

Answers (1)

cs0815
cs0815

Reputation: 17388

Solution. Replace:

object result;

with:

object result = null;

This is Mathworks reponse:

This error is caused by the fact that GetWorkspaceData expect an empty VARIANT as output parameter but after running the loop once, result has actually become a double with value 0.0. So you would need to change your loop into:

foreach (DTO DTO in LotsOfWork)
{

    object result = null; //Initialize as null

    matlab.Execute("clear;");
    matlab.PutWorkspaceData("a", "base", DTO.Parameter1);
    matlab.PutWorkspaceData("b", "base", DTO.Parameter2);
    matlab.Execute("result = a + b;");
    matlab.GetWorkspaceData("result", "base", out result);
}

Upvotes: 2

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