How can I use multiple output arguments from a compiled .NET assembly in Visual Basic?

I have built a .NET assembly of the following MATLAB function:

function [a,b] = TwoOutputs()
[a, b] = eig([1 2;3 4]);

I would like to retrieve 'a' and 'b' in a Visual Basic project.

Answer 1

[MathWorks Support Team]

One of the ways of retrieving multiple output arguments in VB, is by collecting the output in an instance of MWArray, and then creating separate instances of MWNumericArray(s), or equivalent types.

The example below shows how to use the two output arguments of the function described above:

Dim myObj As TwoOutputCompClass = New TwoOutputCompClass()
' Invoke the appropriate constructor for MWArray by explicitly specifying the number of output arguments
Dim argsOut() As MWArray = myObj.TwoOutputs(2)

Dim resultArray1 As MWNumericArray = New MWNumericArray(MWArrayComplexity.Real, MWNumericType.Double, argsOut(0).NumberOfElements)
Dim resultArray2 As MWNumericArray = New MWNumericArray(MWArrayComplexity.Real, MWNumericType.Double, argsOut(1).NumberOfElements)

Dim idx As Integer = Nothing

For idx = 1 To argsOut(0).NumberOfElements
      resultArray1(idx) = (CType(argsOut(0), MWNumericArray))(idx)
      resultArray2(idx) = (CType(argsOut(1), MWNumericArray))(idx)
Next idx

Console.WriteLine("EigVal: {0}", resultArray1)
Console.WriteLine("EigVec: {0}", resultArray2)

For another detailed example, please see the "Spectral Analysis Example" here:

https://www.mathworks.com/help/dsp/ug/high-resolution-spectral-analysis-in-matlab.html