MatLab Automation Server Functions and Properties Feval("load", ...)

I am having problems loading a Matlab workspace in VBA - the error I get is that the call to load cannot find "MatLab.mat" which makes no sense as I have provided the filename "reduce_to_common_factors.mat".

Here is my code down to the line which fails:

{Dim m_MatlabApp As Object

    Set m_MatlabApp = CreateObject("Matlab.Application")

    Dim wkbk As Workbook
    Dim wksht As Worksheet
    Dim ndim As Integer: ndim = 30
    Dim itsdim As Variant

    ReDim rho_matrix(1 To ndim, 1 To ndim) As Double
    ReDim output(1 To ndim, 1 To ndim) As Double
    ReDim my_output_real(1 To ndim, 1 To ndim) As Double, my_output_imag(1 To ndim, 1 To ndim) As Double
    Dim image() As Double, my_bool As Boolean, Result As String

    Set wkbk = Workbooks("Evaluate_LPI_Swap_30y_With_Smile.xlsx")
    Set wksht = wkbk.Worksheets("Modelling_LPI")

    Dim cnt_row As Integer, cnt_col As Integer, retVal As Variant
    wksht.Activate

    'Load the Excel correlation matrix into a double array
    For cnt_row = 1 To ndim
        For cnt_col = 1 To ndim
            rho_matrix(cnt_row, cnt_col) = wksht.Cells(5 + cnt_row, 4 + cnt_col).Value
            output(cnt_row, cnt_col) = 0
        Next cnt_col
    Next cnt_row

    'update the workspace variables in MatLab
    Result = m_MatlabApp.Execute("cd Q:\Team\Russell_Bickerton\MatLab\Data")
    retVal = m_MatlabApp.Feval("load", 0, "reduce_to_common_factors.mat")}

The help topic for this function call is MatLAB, Functions, External Interfaces, MATLAB COM Automation Server Support, MatLAB Automation Server Functions and Properties.

Answer 1

[Friedrich]

Hi,

with respect to the IDL signature:

HRESULT Feval([in] BSTR functionname, [in] long nargout, 
[out] VARIANT* result, [in, optional] VARIANT arg1, arg2, ...)

I guess this

m_MatlabApp.Feval("load", 0, "reduce_to_common_factors.mat")}

needs to be

 m_MatlabApp.Feval("load", 0, Nothing, "reduce_to_common_factors.mat")}

Or maybe instead of Nothing use vbNull. Not sure what you need exactly.