MATLAB and C++ Automatic coupling

Hi support,

I would like to develop an automatic coupling between C++ and MATLAB .

In simple Word:

• - Import in C++ the data from a .mat file
• - Run the simulation in C++
• - Export the results back in a .mat file

Based on the above details of my case, could you advise me for a way to start with?

Please let me know if you require any further clarifications.

Thank you for your continuous support.

Yahia Alabbasi B.C.Eng (Hons) Research Assistant- Qatar University-Department of Civil and Architectural Engineering

Answer 1

[Madheswaran]

Hi Yahia,

You can achieve automatic coupling between C++ and MATLAB using the MAT-File API to read and write MAT files directly from C/C++. Here is a simple workflow you can follow:

// Read data from input MAT file
#include "mat.h"

MATFile *input_file = matOpen("data_input.mat", "r");
if (input_file == NULL) {
    printf("Error opening input file\n");
    return -1;
}

mxArray *data_array = matGetVariable(input_file, "data_array");
if (data_array == NULL) {
    printf("Error reading variable\n");
    matClose(input_file);
    return -1;
}
matClose(input_file);

// ...Your simulation/processing work goes here...

// Save processed data to data_output.mat
MATFile *output_file = matOpen("data_output.mat", "w");
if (output_file == NULL) {
    printf("Error creating output file\n");
    mxDestroyArray(data_array);
    return -1;
}

int status = matPutVariable(output_file, "data_array", data_array);
if (status != 0) {
    printf("Error writing variable\n");
}

matClose(output_file);
mxDestroyArray(data_array);

Please note that the MAT-File API has limited class support, as it doesn't accommodate MATLAB objects from user-defined classes, and it lacks thread safety, meaning its functions can only be used on a single thread at a time to avoid issues, as mentioned here: https://mathworks.com/help/matlab/matlab_external/custom-applications-to-read-and-write-mat-files.html

If you need to work with user-defined classes, you can explore the MATLAB Engine API for C++. The Engine API allows you to start MATLAB sessions, call MATLAB functions directly, handle user-defined classes, and execute MATLAB commands from within your C++ application.

For more detailed information, please refer to the following documentations:

1. https://mathworks.com/help/matlab/matlab-c-api-to-read-mat-file-data.
2. https://mathworks.com/help/matlab/cc-mx-matrix-library.
3. https://mathworks.com/help/matlab/matlab_external/creating-a-mat-file-in-c.html

Hope this helps!