Plot x-axis and y-axis with mexCallmatlab

Hello,

In my S-function written in C I use the function mexCallmatlab to plot the content of an array and it works as I want:

   real_T Gain[205];

   // Some code to fill the array Gain

   // convert array to mxArray
    mxArray* x_ptr_gain; // Pointer 
    x_ptr_gain = mxCreateDoubleMatrix(1, 205, mxREAL);
    memcpy(mxGetPr(x_ptr_gain), Gain, sizeof(double)*205);
    mexCallMATLAB(0,NULL,1,&x_ptr_gain,"plot");

Matlab plots on the y-axis the content of my array and on the x-axis the vector number 1,2…205.

Now I would like to have on the x-axis the content of an other vector freq, which has of course the same size than Gain:

   real_T freq[205];

What do I have to change to get want I want? I tried a few things, but as I am not very sure how all these structures work, I may have done mistakes and giving me the solution would be really nice :)

Thanks.

Answer 1

[Kaustubha Govind]

You need to use the plot(x,y) form of PLOT:

   // Copy freq into an mxArray x_ptr_freq
   mxArray* x_ptr_freq = mxCreateDoubleMatrix(1, 205, mxREAL);
   memcpy(mxGetPr(x_ptr_freq), freq, sizeof(double)*205);
   ...
   mxArray *prhs[2] = {x_ptr_freq, x_ptr_gain};
   mexCallMATLAB(0,NULL,2,prhs,"plot");
   ...
   // Cleanup
   mxDestroyArray(x_ptr_freq);
   mxDestroyArray(x_ptr_gain);