MATLAB Answers

Get variables from my Matlab workspace

17 views (last 30 days)
I am using C mex S-function to Generate a Simulink Block called sFct_Dyn_Block by the following mex file:
mex -D__SIM_MODE__ src_Dyn_Block\sFct_Dyn_Block.c src_Dyn_Block\Dyn_Block.c src_Dyn_Block\hyd_dyn.c src_Dyn_Block\hst.c
The sequence of my code:
  1. I run a matlab file called input_users.m to collect some user inputs
  2. the user inputs are now in matlab workspace
  3. when I run my mex class I need to pass these variables some how from matlab workspace to my hyd_dyn.c class
  4. finally when I run my simulink model the output of sFct_Dyn_Block should change every time according to the userinputs
I can't pass the userinput variables from matlab workspace to my hyd_dyn.c class, I tried everything for 4 days but nothing workout.
I appreciate any help !!

  3 Comments

Ajith Thomas
Ajith Thomas on 29 Oct 2019
how i can define simulink variables through m-script?
Ajith Thomas
Ajith Thomas on 4 Nov 2019
Thanks for your valuable feedback. Its working!!!!!!

Sign in to comment.

Accepted Answer

Thomas Satterly
Thomas Satterly on 28 Oct 2019
You should be using either inports or parameters to pass data from Matlab to you Simulink block. The "From Workspace" block works easily enough (you can just type in the name of your workspace variable). S-function parameters can be set in the Block Parameters window of the S-function block (double click on the block) and require a little more C code to set up properly, but is still easy enough. Does your S-function currently use any inputs?

  3 Comments

Moataz Aly
Moataz Aly on 28 Oct 2019
yes S-function had a signal input, I got what you mean but I think It will be more complicated than getting the variable directly from my S-function for example
const mxArray *array_ptr;
double *temperature;
array_ptr = mexGetVariable("base", "hyd_kannal_daten");
if (array_ptr == NULL){
mexPrintf("Could not get the variable named hyd_kannal_daten from matlab Workspace.\n");}
temperature = mxGetPr(array_ptr);
mexPrintf("Value of user choice [hyd_kannal_daten]=%f\n", temperature[0]);
Thomas Satterly
Thomas Satterly on 28 Oct 2019
I think you want to reference the workspace "caller" instead of base, as I beleive the "base" workspace references the Simulink model workspace, wheras the caller would be the Matlab command line
Moataz Aly
Moataz Aly on 29 Oct 2019
It should be something like this !
const mxArray *array_ptr;
double *hyd_kannal_daten;
array_ptr = mexGetVariable("base", "hyd_kannal_daten");
if (array_ptr == NULL){
mexPrintf("Could not get the variable named hyd_kannal_daten from matlab Workspace.\n");}
hyd_kannal_daten = mxGetPr(array_ptr);
The function returns a pointer to the first mxDouble element of the real part of the data.
mexPrintf("Value of user choice [hyd_kannal_daten]=%f\n", hyd_kannal_daten[0]);
I think this should be the logic required, Thanks for your help !!

Sign in to comment.

More Answers (0)

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by