Disclaimer: I'm not a professional simulink/matlab programmer
If I've opened simulink and created a model, then i want to save it from the commandline in matlab. The save_system works, but I also want to specify a filename, for this i need to use save_system(sys, newsysname.slx)
I can't seem to find a function to get sys. How can I get the same sys as save_system() uses?
Use gcs to get the current system or bdroot to get the top-level of the model. find_system may also be useful.
Related
Fairly simply question, but I cannot find an answer via Google or on Stack.
I have a use-case where it would be highly-preferable to simply read a .m MATLAB script from a URL.
How should I do this correctly?
<disclaimer>
Clearly only do this with files you have complete control of (and/or find a solution with better validation). This is a "dangerous" method as there is no check that you're not about to run a file which, for example, copies your entire harddrive to Bob's computer before corrupting it all. Bob and Alice might be spending the whole evening laughing at your embarrassing holiday photos.
Treat this more as a proof of concept than a how-to, it addresses your problem but by no means should be used in production code.
</disclaimer>
You'll need to use eval to evaluate code. Every time I mention eval I feel compelled to point out it's not recommended, in particular in this case because you could be evaluating whatever random code is living in that file on the web! In this case your only alternative is to save the file locally and call run.
Then you can use
eval(urlread('http://myscript.m'))
or, since urlread is not recommended (from the docs), you can use webread and specify that the output should be text in the options
eval(webread('http://myscript.m', weboptions('ContentType', 'text')))
Using webread appears to be really slow, not sure why when it's the recommended function. In light of this, urlread might be preferable.
There is a note in the webread docs which suggests you wouldn't even need to specify the weboptions
If a web service returns a MATLAB® file with a .m extension, the function returns its content as a character vector.
Although you suggested that webread returned a uint8 variable which didn't work.
If you'd like to save a file from a URL then run it, you can use websave and str2func like so:
fcnName = 'newscript'; % Name for the function/script file
websave([fcnName '.m'], 'http://myscript.m'); % Download and save it
fcn = str2func(fcnName); % Create function handle
fcn(); % Evaluate function/script
It should of course go without saying that you want to be really sure you can trust the source of the file, otherwise you're gonna have a bad time.
I am running Simulink using FastRestart, as I need to start and stop the simulation multiple times changing parameters. When I run Simulink from the main script, there are no problems. However, as soon as I make the script a function so that I can run it for different input data, I get an error that is clearly related to Simulink not seeing the Matlab workspace within the function.
To be more precise, say sfile is my Simulink file, then I run the following lines AFTER having initialized all variables I need in structures in Matlab:
load_system(sfile);
set_param(sfile,'FastRestart','on');
set_param(sfile,'SaveFinalState','on');
set_param(sfile,'SaveCompleteFinalSimState','on');
set_param(sfile,'SimulationCommand','update');
At the last line, I get the error that Simulink does not recognize mdl.tStep (which is the time step), as mdl is not a recognized structure. In fact, it is and if I run Simulink from the main script everything is fine.
Now, in the past, I would have used
options = simset('SrcWorkspace','current');
However, an expert I know has advised me against simset (as it may get deprecated in the future) and encouraged me to use set_param instead. I have
looked up the options for set_param on-line, but I could not find the setting for the Matlab workspace.
Any help would be greatly appreciated. Thank you in advance!
In many instances it is better to use the Model Workspace rather than the Base Workspace:
hws = get_param(model, 'modelworkspace');
hws.assignin('mdl',mdl);
At least be aware that this option exists.
A solution to your problem might be to use the assignin-function to all the variable whose value you want to pass to simulink in your matlab base workspace. To do so just use
assignin('base','mdl',mdl)
Having the variable in your base workspace should allow simulink to see it.
I'm using a MATLAB function block within a Simulink model. I build this model and run it on a dspace system with 1 kHz. To evaluate my experiment I need the data (20x20 double array) that is calculated in my MATLAB function block. Is it possible to export the data to the base workspace?
To read a variable from your system, the easiest way to do so is using ControlDesk. Create a project and download/start your experiment using ControlDesk, then it is automatically aware of the running application and can read the variable. You now have to configure a Measurement (or Capture in old versions) and export the results to MAT. You can find detailed instructions in the documentation from dSPACE, called HelpDesk.
Alternatively you can use the XIL-API or HIL-API to automate the above steps.
I have a Simulink model, the purpose of which is automated code generation.
My model uses S-functions (developed by another party), which has hard-coded assumptions about the path. For instance, several external data files are needed, which are referenced in the S-function via a relative path like ..\Bin\data\datafile.bin. This makes it necessary to set MATLAB's current working directory to a specific path before the model can be run.
I can automatically check and set the correct path via model callback functions. However, all model callback functions only seem to be related to the simulation process, not the build process. That means that I can run the model irrespective of what directory I'm in, but when I try to build the model, it always fails unless I manually navigate MATLAB back to the correct directory.
Needless to say, that's quite annoying. So I was wondering if there is something like a "preBuildFcn" callback fnuction, a function that is run before starting the build process? Any other solution (that does not involve modifying the S-function) is also very welcome.
There are plenty of hooks into the build process of Simulink / Embedded Coder ('entry', 'before_tlc', 'after_tlc', 'before_make', 'after_make', 'exit', and 'error'). I assume you want an 'entry' hook.
All you need to do is write an M-function with the name your_system_target_file name_make_rtw_hook, as explained in the documentation Customize Build Process with STF_make_rtw_hook File.
In case you can't open the online documentation (login required), here is the path to the HTML in your MATLAB installation: MATLAB root\help\rtw\ug\customizing-the-target-build-process-with-the-stf-make-rtw-hook-file.html
I am not sure whether building simulink models is sufficiently similar to building regular MATLAB programs, but here is what I used in the past:
Set up the project manually
Build the project programmatically
The program that is used to build the project should be able to set the path or do other custom things.
I am new to using GUIDE and using GUIs in Matlab.
I am running a script in Matlab that will accept initial inputs from the user and then proceed to open up a GUI (created with GUIDE) which will accept further inputs from the user. However, I cannot figure out a way to transfer variables and data between my script and my GUI. I am aware that script variables/data and GUI variables/data are saved in different workspaces; I just need some simple way to communicate between the two.
Thanks.
A simple way would be to use setappdata and getappdata in order to store your variables/input/whatever so that it's accessible from wherever you want.
Let's say you delcare some variable in your script that you want to retrieve in your GUI:
A = rand(100,100);
Then using setappdata like the following:
setappdata(0,'VariableName',A);
will store the data in the root directory (the 0 as the 1st input), meaning that using getappdata like this in the GUI:
A_in_GUI = getappdata(0,'VariableName');
will allow you to retrieve the value from your GUI, or from any other script as long as you use the correct variable names of course. Notice that you can use a handle to some figure/GUI where you could save your data, like this;
setappdata(handles.Something,'VariableName','A);
but if you close the figure, for instance, you might not be able to retrieve your variable.
As Tyler pointed out, a nice way to share data between different callbacks inside your GUI is to use its handles structure. More info here.
Final Note:
If you don't want to spend your time sharing many variables between scripts and GUIs, you can store all of your variables in a single large structure and use setappdata/getappdata only on this structure, which will keep all your variables updated.
For instance, you can write something like this in the script:
Variables_Structure.MyFavoriteNumber = pi;
Variables_Structure.MyFavoriteSport = 'ice hockey';
setappdata(0,'MyVariables',Variables_Structure);
and then getappdata in the GUI in which you want to use the variables:
Variables_in_GUI = getappdata(0,'MyVariables');