Problem with mex file!

Question

Matteo 2013-6-6

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此问题的直接链接

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Hello there, I'm writing some codes in matlab that calls some mex subroutines. I don't know why, I have a problem with one of these mex subroutines: MATLAB is working well when I call it with 7 inputs, but it is crashing, as I add an eighth variable as imput.

This is the main code:

#include<stdio.h>
#include<stdlib.h>
#include <math.h>
#include<time.h>
#include <unistd.h>
#include <mex.h>
#include <matrix.h>
void rejectsam(double *y, double *p, double *r, double *w, double *ww, double *mx, double *cv, double *c2v, double *u, double *xx) { 
  int j,t,h, flag, count, m, m2;
  double meanz[2][1]={},sigmz[2][2]={}, meanz2[6][1]={},sigmz2[6][6]={}, Ycat[76672]={}, Ycat2[76672]={}, aux2[2][1]={}, aux[6][1]={}, aux3[3][1]={},aux3b[3][1]={}, L2[2][2]={}, L6[6][6]={},Z[8][76672]={}, omegai[9][9]={},
    beta[9]={}, Ycont[76672]={},meanb[2][1]={}, sigmab[2][2]={}, meany12, vary12, mis[76672]={}, invaux[3][3]={}, invomega[3][3]={}, omega0238[6][3]={}, omega0238t[3][6]={}, interm[6][3]={}, interm2[6][6]={}, cov[76672], cov2[76672];    
  memcpy(&omegai, y, sizeof(omegai));
  memcpy(&beta, p, sizeof(beta));
  memcpy(&Ycont, r, sizeof(Ycont));
  memcpy(&Ycat, w, sizeof(Ycat));
  memcpy(&Ycat2, ww, sizeof(Ycat2));
  memcpy(&mis, mx, sizeof(mis));
  memcpy(&cov, cv, sizeof(cov));
  memcpy(&cov2, c2v, sizeof(cov2));
  for (j=0;j<3;j++) {
    for (t=0;t<3;t++) invaux[t][j]=omegai[t][j];
    }
  for (j=0;j<2;j++) {
    sigmab[j][j]=1;
    meanb[j][0]=beta[j+1];
    }
/*here I don't copy some stuff that doesn't matter because it still crash if I put them as comment*/
memcpy(u, &Z, sizeof(Z));
memcpy(xx, &Ycont, sizeof(Ycont));
printf("%f %f %f %f\n",omegai[0][0], cov[0], beta[2], cov2[20000]);
}
void mexFunction( int nlhs, mxArray *plhs[],
                  int nrhs, const mxArray *prhs[])
{
  double *y,*u, *p, *w, *r, *mx, *xx, *ww, *cv, *c2v;
    /*  check for proper number of arguments */
    /* NOTE: You do not need an else statement when using mexErrMsgIdAndTxt
       within an if statement, because it will never get to the else
       statement if mexErrMsgIdAndTxt is executed. (mexErrMsgIdAndTxt breaks you out of
       the MEX-file) */
    if(nrhs!=8) 
      mexErrMsgIdAndTxt( "MATLAB:xtimesy:invalidNumInputs",
              "Eight inputs required.");
    if(nlhs!=2) 
      mexErrMsgIdAndTxt( "MATLAB:xtimesy:invalidNumOutputs",
              "Two output required.");
    /*  create a pointer to the input matrix y */
y = mxGetPr(prhs[0]);
   /*  create a pointer to the input matrix p*/
p = mxGetPr(prhs[1]);
    /*  create a pointer to the input matrix r */
r = mxGetPr(prhs[2]);
     /*  create a pointer to the input matrix w */
w = mxGetPr(prhs[3]);
    /*  create a pointer to the input matrix ww */
ww = mxGetPr(prhs[4]);
  /*  create a pointer to the input matrix mx */
mx = mxGetPr(prhs[5]);
/*  create a pointer to the input matrix cv */
cv = mxGetPr(prhs[6]);
/*  create a pointer to the input matrix c2v */
c2v = mxGetPr(prhs[7]);
   /*  set the output pointer to the output matrix */
plhs[0] = mxCreateDoubleMatrix( 8, 76672, mxREAL);
    /*  create a C pointer to a copy of the output matrix */
u = mxGetPr(plhs[0]);
/*  set the output pointer to the output matrix */
plhs[1] = mxCreateDoubleMatrix( 1, 76672, mxREAL);
    /*  create a C pointer to a copy of the output matrix */
xx = mxGetPr(plhs[1]);
    /*  call the C subroutine */
rejectsam(y,p,r,w,ww,mx,cv,c2v,u,xx);
}

It all works perfectly until I add the variable c2v, which I'm sure is a 76672 doubles vector. It is 3 days that I'm trying to sort it out, the only thing I can imagine is that maybe there is some limit in the number of inputs I can pass to a mex function... In the last line of the main program, if I didn't put between the variables to print cov2, then the program works, so it seems that it crashes only when I consider this variable... Do you have any idea? Thanks in advance! Ps: when I say "crashes" I mean that Matlab window just closes without any message or so, I just have to re-launch Matlab...

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Jan 2013-6-6

编辑：Jan 2013-6-6

There is no magic limit for the number of inputs.

Could you please specify where the function crashes?

Your methods to copy the values could be simplified, when you use the count j for bother sides, or even better, call memcpy instead of the loops.

Matteo 2013-6-6

编辑：Matteo 2013-6-6

在 MATLAB Online 中打开

The function crash as soon as I do something with the new variable "cov2". In the case of the code posted above, it happens when I call

printf("%f %f %f %f\n",omegai[0][0], cov[0], beta[20000], cov2[20000]);

Thank you for the memcpy suggestion, I didn't know that.

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Answer 1

Friedrich 2013-6-6

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/78201-problem-with-mex-file#answer_87904

Hi,

have you tried debugging your MEX?

http://www.mathworks.com/help/matlab/matlab_external/debugging-c-c-language-mex-files.html

This way you can figure out the line which makes it crash and then most likely the reason of the crash.

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Friedrich 2013-6-11

编辑：Friedrich 2013-6-11

在 MATLAB Online 中打开

I think you always need to start MATLAB from the terminal in which you run ulimit -s unlimited. So open a Shell, run ulimit ..., start MATLAB from that shell, recompile the mex, run the mex. At least this way it works for me.

I also changed the rectsam routine a bit in order to be sure to get the correct adress for the memcpy (i dont trust compilers that much ;))

void rejectsam(double *y, double *p, double *r, double *w, double *ww, double *mx, double *cv, double *c2v, double *u, double *xx) { 
   int j,t,h, flag, count, m, m2,test;
   double meanz[2][1],sigmz[2][2],
          meanz2[6][1],sigmz2[6][6],
          Ycat[76672], Ycat2[76672],
          aux2[2][1], aux[6][1],
          aux3[3][1],aux3b[3][1],
          L2[2][2], L6[6][6],
          Z[8][76672], omegai[9][9],
          beta[9], Ycont[76672],
          meanb[2][1], sigmab[2][2],
          meany12, vary12, mis[76672],
          invaux[3][3], invomega[3][3],
          omega0238[6][3], omega0238t[3][6],
          interm[6][3], interm2[6][6],
          cov[76672], cov2[76672];
      mexPrintf("start \n");
      memcpy(&(omegai[0][0]), y, sizeof(omegai));
      mexPrintf("1 \n");
    memcpy(&(beta[0]), p, sizeof(beta));
      mexPrintf("2 \n");
    memcpy(&(Ycont[0]), r, sizeof(Ycont));
      mexPrintf("3 \n");
    memcpy(&(Ycat[0]), w, sizeof(Ycat));
      mexPrintf("4 \n");
    memcpy(&(Ycat2[0]), ww, sizeof(Ycat2));
      mexPrintf("5 \n");
    memcpy(&(mis[0]), mx, sizeof(mis));
      mexPrintf("6 \n");
    memcpy(&(cov[0]), cv, sizeof(cov));
      mexPrintf("7 \n");
    memcpy(&(cov2[0]), &(c2v[0]), sizeof(cov2));*/
      mexPrintf("loops %i\n",cov2[76671]);
    for (j=0;j<3;j++)
      {
      for (t=0;t<3;t++)
              invaux[t][j]=omegai[t][j];
      }
    for (j=0;j<2;j++)
      {
      sigmab[j][j]=1;
      meanb[j][0]=beta[j+1];
      }
      mexPrintf("copy \n");
memcpy(&(u[0]), &(Z[0][0]), sizeof(Z));
memcpy(&(xx[0]), &(Ycont[0]), sizeof(Ycont));
mexPrintf("done \n");
}

Matteo 2013-6-11

Yeah!!!! It works fine!!! Thank you sooo much Friedrich! I cannot really tell you how am I grateful! When you go to sleep this evening you can think that you did your good deed for today! :D

Friedrich 2013-6-11

Yay. great. I guess I will have a few beer to celebrate that tough one^^

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