Transfer struct from Matlab to C + +

I use the library from r2011b stand Matlab to C + +, because there will be where my application will not be installed Matlab. I have a problem with the fact that I need to create a complex subject, and this takes more time, I can not afford to rebuild it every time.

This array is created in Matlab as a struct, I write it to a file "filename.mat" and then open it with matOpen("filename.mat", "r") But the object is empty or not read correctly. One of its fields is an array. When I try to use an object in the library, I get the error:" Attempt to reference field of non-structure array ".

Is there a solution to this problem?

[José-Luis]

Could you post some minimum working example?

[Alexmyak]

  #include "stdafx.h"
  #include "sfam.h"
  #include "mclmcrrt.h"
  #include "stdio.h"
  #include <stdlib.h>
  #include <iostream>
  int _tmain(int argc, _TCHAR* argv[])
  {
    mclInitializeApplication(NULL, 0);
    sfamInitialize();        
    // //reading network
    MATFile* netfile =  matOpen("newstruct.mat", "r");   
    mxArray* net = matGetVariable(netfile, "tnet");
    // //reading data
    MATFile* netdatafile =  matOpen("minidata.mat", "r");   
    mxArray* data = matGetVariable(netdatafile, "minidata");    
    mwArray res;
    mwArray debug;    
    mwArray mwnet = mwArray(net);
    mwArray mwdata = mwArray(data);
    classify(1,res, mwdata, mwnet  ,debug);
    matClose(netfile);
    matClose(netdatafile);
    sfamTerminate();
    mclTerminateApplication();
    return 0;
  }

Answer 1

[Alexmyak]

I was able to load up the structure, and the data, the code has changed as follows:
                  #include "stdafx.h"
                  #include "sfam.h"
                  #include "mclmcrrt.h"
                  #include "stdio.h"
                  #include <stdlib.h>
                  #include <iostream>
                  int _tmain(int argc, _TCHAR* argv[])
                  {    
                    mclInitializeApplication(NULL, 0);
                    sfamInitialize();        
                    
                    // //reading network
                    MATFile* netfile =  matOpen("D:\\newstruct.mat", "r");  
                    mxArray* net = matGetVariable(netfile, "tnet");
                    
                    std::cout << "2" << std::endl;
                    bool isNetStruct = mxIsStruct(net);
                    std::cout << isNetStruct << std::endl;    
                    
                    // //reading data
                    MATFile* datafile =  matOpen("D:\\data.mat", "r");       
                    mxArray* data = matGetVariable(datafile, "minidata");
                    
                    // //reading labels
                    MATFile* labelsfile =  matOpen("D:\\labels.mat", "r");   
                    mxArray* labels = matGetVariable(labelsfile, "minilabels");                  
                    
                    mxArray *plhs[1];    
                    plhs[0] = NULL;  
                    mxArray *prhs[3];
                    prhs[0] = data;
                    prhs[1] = net;
                    prhs[2] = NULL;
                    mlxClassify(1, plhs, 3, prhs);    
                    matClose(netfile);
                    matClose(datafile);
                    matClose(labelsfile);
                    sfamTerminate();
                    mclTerminateApplication();
                    return 0;
                  }
Now I call a function, not of mwArray, but from mxArray. But I have a problem in the 34 line. The program just hangs, without issuing any messages.

[José-Luis]

Which one is line 34? All I can see is that you're passing a NULL pointer (plhs) to mlxClassify. That is, excuse the pun, pointless.

[Alexmyak]

Thank you! I solve  my problem was indeed an error in the fact that I did not initialize starting output parameters (rlhs). This is the last option, the working code can be useful to someone:

  #include "stdafx.h"
  #include "sfam.h"
  #include "mclmcrrt.h"
  #include "stdio.h"
  #include <stdlib.h>
  #include <iostream>
  int _tmain(int argc, _TCHAR* argv[])
  {    
    mclInitializeApplication(NULL, 0);
    sfamInitialize();        
    
    // //reading network
    MATFile* netfile =  matOpen("D:\\newstruct.mat", "r");  
    mxArray* net = matGetVariable(netfile, "tnet");
        
    bool isNetStruct = mxIsStruct(net);    
    
    // //reading data
    MATFile* datafile =  matOpen("D:\\data.mat", "r");       
    mxArray* data = matGetVariable(datafile, "minidata");
    
    // //reading labels
    MATFile* labelsfile =  matOpen("D:\\labels.mat", "r");   
    mxArray* labels = matGetVariable(labelsfile, "minilabels");                  
    mxArray* res = mxCreateDoubleMatrix(1, 1, mxREAL);
    mxArray* debug = mxCreateDoubleMatrix(1, 1, mxREAL);
    mxArray* plhs[1];    
    plhs[0] = res;  
    mxArray *prhs[3];
    prhs[0] = data;
    prhs[1] = net;
    prhs[2] = debug;
    
    mlxClassify(1, plhs, 3, prhs);    
    double* dRes = mxGetPr(plhs[0]);
    for(int i = 0; i < 3;i++){
    std::cout << dRes[i] << std::endl;
    }    
    matClose(netfile);
    matClose(datafile);
    matClose(labelsfile);
    sfamTerminate();
    mclTerminateApplication();
    return 0;
  }

Answer 2

[alan wang]

how's your mlxClassify implemented?