Visual Servoing Platform  version 3.6.1 under development (2024-09-09)
tutorial-matlab.cpp

Tutorial using ViSP and MATLAB Determine column-wise sum of ViSP matrix using MATLAB Engine

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <engine.h>
#include <matrix.h>
#include <visp3/core/vpConfig.h>
#include <visp3/core/vpMatrix.h>
int main()
{
#ifdef ENABLE_VISP_NAMESPACE
using namespace VISP_NAMESPACE_NAME;
#endif
// ViSP matrix containing input data
vpMatrix x(3, 3, 0);
x[0][0] = 1;
x[0][1] = 2;
x[0][2] = 3;
x[1][0] = 4;
x[1][1] = 5;
x[1][2] = 6;
x[2][0] = 7;
x[2][1] = 8;
x[2][2] = 9;
int xCols = x.getCols();
int xRows = x.getRows();
// MATLAB Engine
Engine *ep;
// MATLAB array to store input data to MATLAB
mxArray *T = mxCreateDoubleMatrix(xRows, xCols, mxREAL);
// MATLAB array to store output data from MATLAB
mxArray *D = nullptr;
// Temporary variable to hold Output data
double res[3];
int resCols = 3;
// Display input data to the user
std::cout << "ViSP Input Matrix:" << std::endl;
for (size_t i = 0; i < xRows; i++) {
for (size_t j = 0; j < xCols; j++)
std::cout << x.data[i * xCols + j] << " ";
std::cout << std::endl;
}
// Start a MATLAB Engine process using engOpen
if (!(ep = engOpen(""))) {
fprintf(stderr, "\nCan't start MATLAB engine\n");
return EXIT_FAILURE;
}
// Copy the contents of ViSP matrix to the MATLAB matrix variable T
memcpy((void *)mxGetPr(T), (void *)x.data, xRows * xCols * sizeof(double));
// Place the variable T into the MATLAB workspace
engPutVariable(ep, "Tm", T);
// Determine the sum of each column of input matrix x
// ViSP matrix is row-major and MATLAB matrix is column-major, so transpose the matrix T before evaluation
engEvalString(ep, "Dm = sum(Tm');");
// Get the variable D from the MATLAB workspace
D = engGetVariable(ep, "Dm");
// Copy the contents of MATLAB variable D to local variable res
memcpy((void *)res, (void *)mxGetPr(D), sizeof(res));
// Display output data to the user
std::cout << std::endl << "MATLAB Output Matrix (Column-wise sum):" << std::endl;
for (size_t i = 0; i < resCols; i++)
std::cout << res[i] << " ";
std::cout << std::endl;
// Wait until user exits
fgetc(stdin);
// Free memory, close MATLAB Engine and Exit
mxDestroyArray(T);
mxDestroyArray(D);
engEvalString(ep, "close;");
engClose(ep);
return EXIT_SUCCESS;
}
unsigned int getCols() const
Definition: vpArray2D.h:337
Type * data
Address of the first element of the data array.
Definition: vpArray2D.h:148
unsigned int getRows() const
Definition: vpArray2D.h:347
Implementation of a matrix and operations on matrices.
Definition: vpMatrix.h:169