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
Related
I am looking for a workaround for the following problem:
Create a script foo.m containing fun = #(x)(x*x)
Run foo. This creates the variable fun.
Delete foo.m
Try running fun(2).
In recent versions of MATLAB (I am using R2019b) this results in an error:
Previously accessible file "foo.m" is now inaccessible.
Somehow, the anonymous function is tied to the file in which it was defined.
Is it possible to somehow "detach" it so that it would continue working even after the file was deleted?
For those curious why I need this, it is for fixing MATLink, the Mathematica/MATLAB interface, for recent versions of MATLAB.
You can use func2str and str2func to construct a new function handle that will work:
more_fun = str2func(func2str(fun));
more_fun(2)
Note that after this, fun can still not be found, but you can also assign to fun directly to make it accessible again.
Edit: just found a (documented) limitation: if the anonymous function uses outside variables, this method will not work, because
Function handles created using str2func do not have access to variables outside of their local workspace or to nested functions. If your function handle contains these variables or functions, MATLAB® throws an error when you invoke the handle.
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
I am having a problem with the findpeaks function, this function is in the signal processing toolbox and also the program has another version of it (user defined function). I need to call the on in the signal processing toolbox not the user defined one, also I can't rename the user defined function for many reasons. Can anyone help me in calling the toolbox function.
The precedence order used by MATLAB is described in their help pages. It states that functions in the current folder (9.) are preferred over functions elsewhere in the path (10.). Then, the first appearance of the function in the path is chosen. This allows for a number of possible solutions:
1. cd to folder
A very simple method is simply to change the current workspace directory to the folder of the function you need to call, i.e. cd either to the place where your user-defined function is, or cd to the toolbox path. Note: This is rather inelegant, but probably sometimes the simplest solution.
2. Reorder path
As mentioned, MATLAB choses the first occurence of the function in the path. You can thus re-sort the path variable, so the folder where your user-defined function is, appears last. The path variable can be viewed and manipulated using the path function. Note: Then you can only call the toolbox function. Otherwise you'd have to resort the path again.
3. Function handles
If you need to be able to call both functions, it can be useful to create a function handle for both versions. For that, you have to cd into the folders where the functions are defined and create a new handle there:
cd('path/to/userdefined/function')
userFindPeaks = #findpeaks;
cd('path/to/MATLAB/installation/toolbox/signal/signal')
toolboxFindPeaks = #findpeaks;
You can then call the functions using feval.
Of course, as Adriaan mentions in the comments, it is best not to use the names of already defined functions for your own functions or for variable names.
I just came here looking for the same thing... I ended up using builtin.
https://uk.mathworks.com/help/matlab/ref/builtin.html
[y1,...,yn] = builtin(function,x1,...,xn)
#arr_sea actually posted a link in one of the folded comments which uses this function in a different context.
So I have been trying to call a button callback function in test_gui.m function in non-gui m file say test2.m.
But I fail all the time. I tried using findall or findobj but still I get a problem. could you tell me if there is anything I have to do?
You cannot access any functions in an m file except for the function by which the file is named.
For example, you have an m file named func.m which contains functions func(), helper_func1(), and helper_func2(); only func() will be available to any code outside of that file. See http://www.mathworks.com/help/matlab/ref/function.html: "Local functions are only available to other functions within the same file."
What you want is to create a new file named helper_func1.m containing helper_func1() and then call that function from test2.m as well as inside test_gui.m.
I am using Matlab R2013a and I am trying to use the 'who' function within a function to retrieve a list of variables that begin with a name.
Let's say I have a list of variable in my workspace as follows:
a = 1
a_2 = 2
a_3 = 3
when I run this:
who('a*');
it works fine.
But when I run the same thing inside a function like this:
function someFunction()
who('a*');
end
or
function someFunction()
disp(who('a*'));
end
It doesn't. No error, just no output.
If I had saved those variables in a Matlab file called
myVariables.mat
and run this within the same function like so:
function someFunction()
who('a*','myVariables');
end
It still doesn't work.
I can understand why the first might not work because of scope, but specifying the file to run the 'who' function on should work... what am I missing?
Any help would be appreciated.
Regards
Diaa
As mentioned by #Daniel, the workspace of a function is separate from the base workspace. There are two ways you could use who inside a m-file to inspect the base workspace:
Use a script instead of a function (i.e. omit the function- line; launch the script by its file name as you do with a function): A script shares the base workspace, and thus, who will be able to see all your variables.
Use evalin: evalin('base','who')
You are trying to access variables within a function. Only the input arguments and global variables are visible within a function. You have to do something like:
function someFunction(a1,a2)
who('a*');
end
If you are really trying to use dynamic variable names, I would strongly recommend to change your design.