Using Feval from C# - handling returned struct

Using the sample code on the website I can call a simple function successfully, but where the returned type is a struct, all I get back is a null, but with no error.

Sample function:

function out = myfunc(y)

out.mean = mean(y); % mean

out.median = median(y); % median

out.std = std(y); % standard deviation

end

My C# code:

static void Main(string[] args)
        {
            MLApp.MLApp matlab = new MLApp.MLApp();

              matlab.Execute(@"cd c:\BF_hctsa\Operations");

              object result = null;

              System.Array input = new double[10];
              for (int i = 0; i < 10; i++)
              {
                  input.SetValue(1.0, i);
              }

              matlab.Feval("myfunc", 1, out result, input);

              object[] res = result as object[];

              Console.WriteLine(res[0]);
              Console.ReadLine();
          }

Answer 1

[Preethi Ayyamperumal]

MATLAB does not support the following COM interface types:

• Structure
• Sparse array
• Multidimensional SAFEARRAYs (greater than two dimensions)
• Write-only properties

The workaround is to return fields of the desired struct from the MATLAB function when using Feval. Please refer to the updated code below:

MATLAB Code:

function [out.mean,out.median,out.std] = myfunc(y)
out.mean = mean(y); % mean
out.median = median(y); % median
out.std = std(y); % standard deviation
end

C# code

static void Main(string[] args)
  {
  MLApp.MLApp matlab = new MLApp.MLApp();
  matlab.Execute(@"cd c:\BF_hctsa\Operations");
  object result = null;
  System.Array input = new double[10];
  for (int i = 0; i < 10; i++)
      input.SetValue(1.0, i);
  matlab.Feval("myfunc", 3, out result, input);
  object[] res = result as object[];
  Console.WriteLine(res[0]);
  Console.WriteLine(res[1]);
  Console.WriteLine(res[2]);
  Console.ReadLine();
 }

[javid akhavan]

How do you read the output? I mean I nead to work with the data in res[0] or others, but since they are "objects" I can't use them.

Consider res[0] is soppused to be an Integer

and i want to compare it to 1,

I wrote

if (res[0] == 1)

....

but it wouldn't work