Recently, someone asked us some questions by email. I thought that the questions would be interesting to a wider Matlab programming audience, so I decided to post them here. The questions relate to GUIDE, arrays, and Matlab speed.

Here is the original email:

1st, is the coding for the function of all GUIDE tool linking? For

instance, the coding wrote in pushbutton_callback is connected with coding

wrote in pushbutton1_callback. Is that possible? Or I have to write in

separate .m file, each .m file consists of each function?

2nd, I want to display multiple images in uipanel as you can see in my

coding. So, is it possible to use subplot in uipanel?

3rd, I am totally new in Matlab, so basically immitate source code from

FileExchange or Matlab blogs. There are few errors quite often occurred

and I still can’t clear my doubt thru wiki/google.

For example 1: Attempted to access cell(2,1); index out of bounds because

size(cell)=[1,22]. for preallocate the database.

For example 2: ??? Undefined function or variable ‘Nfile. What does it

means? As I had “defined” it as Nfiles = numel(fnam); Is it something

wrong with my concept?

4th, I found that when run more often .m file, more slower the

performance. Is this the software problem or my computer problem?

Here are my answers to her questions:

* *1. You should be able to declare the callback function when you create

the pushbutton. Therefore, you should be able to use the same callback

function for different pushbuttons. If you want the pushbuttons to do

different tasks but use the same function, you could put a parameter in

your function call that specifies which task you want the function to

perform. You would then put a “switch” statement into your function to

use the parameter.

2. You should be able to use subplot in the UI panel.

3. I am not sure about your errors, because I can’t see your code.

However, I have some ideas about what might be wrong. Matlab uses arrays

for everything. The first index in an array specifies the row, and the

second index specifies the column. If you wanted row 4 and column 7 from

array A, you would type A(4,7). For the first error, it looks like you

are trying to access a location in the cell array that doesn’t exist. If

an array A is 1×22, then you can’t access location A(2,1), because that

array has only one row, and the location that you want is in the second

row. Additionally, be careful not to give any of your variables the name

of a data type or function. If you name a variable “cell”, which is data

type, then you may get strange effects in your code. For the second

error, it seems like you just have a typo. You are trying to use Nfile,

but you had already created a variable named Nfiles.

4. If I understand you correctly, Matlab on your computer runs more

slowly after you have opened it and run several m-files. You should make

sure that you clear your Matlab workspace with the “clear” command after

you run a script. Try to get rid of all the variables that you don’t need

to use, as they can slow down Matlab. If Matlab still runs slow, then try

to restart Matlab. If that doesn’t fix the problem, then try to restart

your computer.

Hello,

Could you please tell me how to read a matlab struct into java using jmatio library.There are no examples online and the documentation is very confusing.

Thank you

Hello,

Could you please tell me how to read a maylab truct from java using jmatio library there are no examples of this online and the jmatio documentation is very confusing.

Thank you

hello

My English is not good

my question is:

with this data,3. X=[1 1 2 3 4 4 4 4; 0 2 0 4 1 4 -1];

Linear Perceptron algorithm written for them and best of show

do and iteration with c=3 ,c=1, c=0.1

batch perceptron with this c.

tnx

How do I increase the font size in the Command Window? I increased the font size

in my XP display but it does not help. Thank you

Alfred

Dear Matlab Geeks and Matlab Users,

I trust you are well and all is good. I would like to know if the Matlab Community can assist me in the following problem I encounter when trying to run my simulation.

I am using Matlab to run a scientific model over South Africa using GNSS network, and this involves MATLAB GUI’s. Below is the errors I encounter.

??? Error using —-> checkgrid

LatIntersect () – Internal parameter exceeds bounds

Error in –> initgrid at 23

[Grid.Voxel, Grid.Dim] = checkgrid ( Grid );

Error in –> @(hObject,eventdata)gmagic(‘Process_Callback,’ hObject,eventdata,guidata(hObject))

??? Error while evaluating uicontrol Callback

There is other m – files that works together to give the GUI. If anyone can be of any assistance it will be highly appreciated.

I Thank You in advance for the above.

Kindest Regards,

Tino

I would be interested in your over rated/underrated analysis using the last AP vote list just BEFORE the bowl season. After the bowl season, I believe there is much more rigging of votes by area of the country to raise or lower teams. (e.g. Texas and southern voters will raise Big12/SEC schools on final ballots, and lower out of school teams even when they win). Plus there is some forced voting built into the final AP vote which might not necesarily reflect what people really think (i.e. see LSU national champions with 2 losses).

how about interp2? =)