Matlab API reading .mat file from c++, using STL container

Question

I have to read some .mat data files from c++, I read through the documentation, but I would like to know how to handle the data in a clean and elegant way, e.g. using std:ve

Answer 1

Here is an example of using the MAT-API:

test_mat.cpp

#include "mat.h"
#include 
#include 

void matread(const char *file, std::vector& v)
{
    // open MAT-file
    MATFile *pmat = matOpen(file, "r");
    if (pmat == NULL) return;

    // extract the specified variable
    mxArray *arr = matGetVariable(pmat, "LocalDouble");
    if (arr != NULL && mxIsDouble(arr) && !mxIsEmpty(arr)) {
        // copy data
        mwSize num = mxGetNumberOfElements(arr);
        double *pr = mxGetPr(arr);
        if (pr != NULL) {
            v.reserve(num); //is faster than resize :-)
            v.assign(pr, pr+num);
        }
    }

    // cleanup
    mxDestroyArray(arr);
    matClose(pmat);
}

int main()
{
    std::vector v;
    matread("data.mat", v);
    for (size_t i=0; i

First we build the standalone program, and create some test data as a MAT-file:

>> mex -client engine -largeArrayDims test_mat.cpp

>> LocalDouble = magic(4)
LocalDouble =
    16     2     3    13
     5    11    10     8
     9     7     6    12
     4    14    15     1

>> save data.mat LocalDouble

Now we run the program:

C:\> test_mat.exe
16 
5 
9 
4 
2 
11 
7 
14 
3 
10 
6 
15 
13 
8 
12 
1