Call "log" functions from c# through COM failed with exceptions.

I am simply testing executing matlab functions through C# by the following,

 var matlab = new MLApp.MLApp();
 var n = new int[10000000];
 var r = new Random();
 for (int i = 0; i < 10000000; ++i)
     n[i] = r.Next(1, 1000000);
 var t = DateTime.Now;
 for (int i = 0; i < 10000000; ++i)
 {
     object result = null;
     matlab.Feval("log2", 1, out result, n[i]);
 }
 Console.WriteLine((DateTime.Now - t).TotalSeconds);

This fails with exceptions: Exception thrown: 'System.Reflection.TargetInvocationException' in mscorlib.dll Exception thrown: 'System.Runtime.InteropServices.COMException' in mscorlib.dll

However, if you test another function "randsample", it will work.

 var matlab = new MLApp.MLApp();
 var n = 1000;
 var t = DateTime.Now;
 for (int k = 0; k < 1000; ++k)
 {
     object result = null;
     matlab.Feval("randsample", 1, out result, n, k);
 }
 Console.WriteLine((DateTime.Now - t).TotalSeconds);

Both are buidin math functions. I don't know why one works but the other does not. Any help is appreciated! Thanks!

Answer 1

[Harsh]

Make sure the correct reference to mlapp.tlb is added in Visual Studio or any other IDE you are using. Also make sure that MATLAB is registered as a COM server. You can read more here:

https://www.mathworks.com/matlabcentral/answers/101093-why-am-i-getting-an-error-when-adding-a-reference-to-matlab-type-library-in-my-visual-studio-project

Additionally make sure you are passing the correct number of input and output arguments.

The following resources may also be useful:

https://www.mathworks.com/help/matlab/call-matlab-com-automation-server.html

https://www.mathworks.com/help/matlab/matlab_external/call-matlab-function-from-a-c-client.html

https://www.mathworks.com/help/matlab/matlab_external/call-matlab-function-from-c-client.html

If the issue persists, please contact MathWorks Technical Support here: https://www.mathworks.com/support/contact_us/

Please be sure to provide a detailed description of the issue and attach any relevant files / code / examples required to investigate the issue.