I am using functions from a MATLAB package ("EEGLAB"). One of the functions I'm using ("pop_selectcomp") creates a GUI. However, when I try to interact with the GUI, an error results: an expected variable (In this case "EEG", a data structure) is not defined. That's odd, because pop_selectcomp has EEG as an input. I discovered that declaring global EEG anywhere in the function stack above my call to pop_selectcomp makes EEG available to it again. This is the structure of my function stack.
Main Script
data import function loads variable "EEG"
function to process data
function call to pop_selectcomp
So declaring EEG as a global in the main script or the data processing function fixes the problem.
My interpretation is that when pop_selectcomp creates its GUI window, it's being created outside of my function stack in the main workspace or something like that. So, the EEG variable is only available to it if it's been declared global above the function call. I'm not very familiar with Matlab figures and GUIs, but I guess that normally pop_selectcomps doesn't have this problem because it's not called as a sub-function.
Is there any better way to make this work? Can I somehow point pop_selectcomps' GUI at the correct sub-workspace where it will find the variables it needs? I can modify pop_selectcomps if I have to, although that would be messier. The function can be found here:
https://sccn.ucsd.edu/svn/software/eeglab/functions/popfunc/pop_selectcomps.m
Related
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 am now using Matlab GUI and have problem during accessing return values from a function which is set by set().
Situation:
I set the windowMotionFcn as below:
set(gcf,'WindowButtonMotionFcn',#test);
Function 'test' can return 2 variables (named as var1 and var2).But I dont know how to store them...
I have searched in the Internet and could not find any way.
How should I write?
Thank you for your help and kind attention.
I think that what you want to do is to return a value from the callback function. And regarding returning a value from a callback I am not sure that is possible. I found an old article from matlab newsreader. I think your problem could be similar.
However, if you have a matlab GUIDE GUI, there is a way to return a value from a gui. It is described in a matlab tutorial in matlab central: advanced-getting-an-output-from-a-guide-gui. What you must do is to modify your CloseRequestFcn and your OutputFcn.
Another way, which should work is using global variables. A global varable exist in the global workspace. That means that it can be seen and accessed by every function in matlab. Global variables are in most cases not recommended, but if no other solution exists they may be necessary. Just make sure to document them, so that the next person to take over your code knows that they are there. Also make sure to select a good name for the globals, like gblMyVar so there can be no confusion that the variable is global.
I'm learning MatLab & hit a roadblock.
I have an interface.fig file with interface.m which is acting as my 'main' GUI window. From there another file; bright.m is called.
The file bright needs to update global variables in the main file as well as call functions, I have worked out the global variables out but cannot call functions.
Tried everything, looked at doing things like:
reDisplay();
evalin('base','reDisplay()');
interface.reDisplay();
interface>reDisplay();
But had no luck.
Only the first function in an M file is callable from outside of that file. If you want your functions to be globally accessible then you need to save them in independent files.
If you need state to be globally accessible between these functions pass them as arguments or consider using an Object Oriented approach to solving your problem.
If a function in Matlab is defined inside an m-file with file name different than function name - then there is no way of calling this function from outside its m-file.
In order for your reDisplay function to be visible to bright.m, you should have this function in its own m-file called reDisplay.m
I have a MATLAB GUI that loads to aid in visually pre-processing data. Essentially it prompts the user to adjust the data range, reduce number of data points, etc... all while providing an updated graph. Upon completion of this work, I want to be able to close out the GUI and pass variables from the GUI to another MATLAB function that does the data analysis. I have found lots of information on how to pass information from a function TO and GUI, but not the other way around.
Any help would be greatly appreciated.
Global variables can cause hard to find bugs. The best solution for your problem (where you want to pass the data directly to another function on close) might be to call the analysis function from the Figure Close Request Function. When the figure your GUI is running in is told to close, it will run the code in this function, which can call your analysis function and have access to the GUI's data.
Matlab GUIs are functions: the code exists in a .m file just like other functions. Like regular functions, they can have return values. You can get as fancy as you want messing with the varargout system, or you can simply return a value, structure, or cell array containing whatever you want. Open up the m-file and edit it to return what you want it to.
Note: If you require special processing when the figure is being closed to generate the appropriate return value, you can reimplement the closeRequestFcn as you see fit.
The easy way: you declare as global variable, where variable stores the data that you want to carry from the GUI to the main MATLAB workspace. Then, you also declare the same global variable on the command window. Hereinafter, variable to be accesible from both scopes, the GUI and the main workspace.
You could also use save or any other alternatives as csvwrite or dlmwrite to store the data into a file, but this doesn't seem to be your case.
I have an object-oriented MATLAB app that needs a GUI, and I'd like to use GUIDE for the layout (at least). I've tried the manual way, and doing the control positioning is just too painful.
I've noticed that GUIDE is very much procedurally-oriented; it generates M-files that assume they are run from the path and aren't associated with any classes or objects.
Has anyone had experience trying to use GUIDE in an object-oriented way? If it's straightforward, I'd like to do automatic code generation as well, but I'm willing to let GUIDE just generate the .fig file and write the code myself.
When you create a gui with guide, for every button/textbox/graph etc. you put on the pane, it automatically generates the shells for the necessary callbacks, so all you have to do is fill in the code. If you change the name of the widgets (their "tags") or add or delete them, it updates your m-file for you, which is handy.
You can associate your gui with objects; the autogenerated m-file has a function outline that looks like this
function YourGUIName_OpeningFcn(hObject, eventdata, handles, varargin)
you can require that someone pass your gui an object or objects through the varargin. The canonical matlab way to do this is to pass parameter name/value pairs, so the call from the command line would look like
YourGuiName('importantobject', object1);
but you could also (especially if there is just one unique argument) assume varargin{1} is a specific parameter, varargin{2} is a second, and so on
In this case, the call from the command line would be
YourGuiName(object1);
In your openingfcn, you would then add a line like
if (length(varargin) < 1) || ~isa(varargin{1}, 'importantObjectType')
error ('you must pass an importantobject to YourGuiName, see help');
end
myimportantobject = varargin{1}
You now have a choice to make. The canonically correct way to store data in your gui is to put it in the handles structure and then store it with guidata, as in
handles.myobject = varargin{1};
guidata(hObject, handles); %this is just boilerplate
The boilerplate is necessary because, despite its name, handles does not subclass Handle, and is passed by value, not reference. the guidata command sticks handles somewhere associated with the gui figure so you can get it in subsequent callbacks.
The problem with this approach is that when you put a large object in handles, it makes the guidata command take forever. This is true even though MATLAB is not supposed to copy data when passing by value unless absolutely necessary, and it is even true if your object is a Handle, which takes like 4 bytes to pass back and forth. Don't ask me why, but I suspect it has something to do with memory management & garbage collection.
If your gui is taking a while to execute commands, and you use profile and see it hanging on the guidata command, you should just declare your object to be a global and deal with it that way
global YOURGUI_object; %it's not my fault; blame MATLAB
YOURGUI_object = varargin{1};
Then you can just have all your callbacks execute whatever method of YOURGUI_object they need.
Good luck.