Motivation
MATLAB is an excellent tool for scientific computing.
It can be used either as installed desktop or MATLAB online versions.
MATLAB is offered as a coursework in most of the universities. It can be Introduction to MATLAB programming or simulation tool for signal/image processing ,operations research or differential equations to name a few courses.
The visually impaired students use screen readers (like JAWS, and NVDA) to operate the computer.
The MATLAB online is fully accessible, but some recent versions of MATLAB desktop are inaccessible to screen readers.
Doing coursework assignments on online version may not be a good idea, so making the desktop version accessible is a necessity.
the cost effective method is operating MATLAB via the windows command line option.
So in this blog post, running MATLAB through windows command line(CMD) is explained.
This will help the screen reader users confidently take the course works with MATLAB.
The visually impaired are encouraged to ask their doubts regarding MATLAB.
THE readers of this blog especially Screen reader users are encouraged to discuss the problems they try to solve with MATLAB. i tested all the codes presented in this blog, with NVDA, JAWS and Narrator.
you can have a look at my MATLAB central file exchange page.
https://www.mathworks.com/matlabcentral/profile/authors/1281371
i usually publish my code after I tested it
So If you have a problem to solve, present a similar problem to me through the comments section.
I will try in such a way that the concept can be learned with MATLAB. thanks for reading. All the best !!!.
1. Introduction
MATLAB renowned for its numerical computation and visualization capabilities, can seamlessly interact with the Microsoft Windows command line (CMD).
This integration allows you to leverage the power of both environments, executing system-level commands from within MATLAB scripts and automating tasks by combining MATLAB functionality with CMD scripts (known as batch files with extention .bat).
This synergy enhances workflow efficiency and expands MATLAB's application beyond its inherent capabilities.
whenever you come across uppercase `MATLAB` word means that it denotes the MATLAB application .
The lower case `matlab` is the command used to run MATLAB application on windows. So always use left and right arrow keys in your screen reader to confirm the case or symbol.
(the graph ` symbol is used in this blog post to indicate commands and path notations, so ignore the graph symbol and use the command inside.).
In this blog post we are going to run a `matlab` script named main.m.
the program and command window outputs are written as text or csv files.
MATLAB program code: main.m
```
%this code writes a data contained in a cell array and saving graph in .png and .jpeg formats.
%it is better to format the output results as a cell array which can contain many data formats.
clear;
clc;
data={'salo',44,'m',1000;'lyla',8,'f',0};
%writing the results to a csv file
fileID = fopen('r1.csv', 'w');
if fileID == -1
error('Could not open file for writing.');
end
% Write header row
fprintf(fileID, 'number,name,age,sex,income\n'); % Comma separated
% Write data rows
for i = 1:2
fprintf(fileID, '%d,%s,%d,%s,%d\n', i, cell2mat(data(i,1)),cell2mat(data(i,2)),cell2mat(data(i,3)), cell2mat(data(i,4)));
end
fclose(fileID);
disp('Data written to r1.csv');
%plotting a sine wave and saving it
figure(1)
x=0:.1:2*pi;
y=sin(x);
title('sine wave')
xlabel('x axis');
ylabel('y axis');
plot(x,y)
grid on; % Adds a grid to the plot (optional)
% --- Save the plot as a PNG file ---
filename_png = 'sine_wave.png'; % Name of the PNG file
saveas(gcf, filename_png); % gcf = Get Current Figure
% --- Save the plot as a JPEG (or JPG) file ---
filename_jpeg = 'sine_wave.jpeg'; % Name of the JPEG file
saveas(gcf, filename_jpeg); % Or you can use 'sine_wave.jpg'
disp('figures written as png and jpeg formats. ');
```
2. Methods of using MATLAB with windows CMD
2.1. running MATLAB in batch mode:
Running MATLAB in batch mode means ,the program runs only in the backround. suitable for non interactive scripts. Of course interaction is possible if the script is written as a function file.
the syntax is
`matlab -batch main -logfile log.txt`
explanation:
the first lowercase `matlab` means matlab command.
`-batch` means the program runs only in the backround, not visible. The command window/error messages written to logfile named log.txt.
main the script file is written without extention.
`-logfile log.txt` means the program outputs written as a log.txt. you can change the log.txt to any name you prefer.
2.2.Using `matlab -r`
the Most Reliable method is the matlab followed by `-r` ) ) followed by a string containing the script name and exit command.
This is the most straightforward and generally preferred method.
```batch
```
matlab -r \"run('main.m'); exit;\" -logfile log.txt
```
use your screen reader left and right arrow keys to familiarize with the above command.
the commands have following parts
`matlab` the matlab command
`-r` indicator to run the script.
\"run('main.m');exit;\'
You can replace main.m with your script name.
if your script name is main1.m, then the command you should use on windows cmd is...
`matlab -r \"run('main1.m'); exit;\" -logfile log.txt`
-logfile log.txt : the output of command window with errror messages(if any) are written to log.txt. you can change log.txt to any name.
Explanation
matlab : This invokes the MATLAB executable.
-r: This (minus sign followed by r) is the \"run\" option. It tells MATLAB to execute the string that follows as a MATLAB command.
\"run('main.m'); exit;\" : This is the MATLAB command string.
`run('main.m')`: Executes the MATLAB script named `main.m` in your default folder.
Make sure to replace `main.m` with the actual filename.
If the script is not in the current directory, you have to specify the full path of the file.
Example
If the path of the file main.m is
`c:\\folder1\\folder2\\main.m`
them the run command should be
`run('c:\\folder1\\folder2\\main.m')`
exit; : This is crucial! It tells MATLAB to close after the script finishes executing. Without `exit`, MATLAB will remain open in the command window, waiting for further commands, and you won't see the command prompt return.
If the script needs some input then the MATLAB command window will not exit. You have to type the input at the open MATLAB command window and press enter key.
3. Example (assuming main.m is in your current directory):
```batch
matlab -r \"run('main.m');exit;\"
(if `main.m` is in `C:\\folder1\\folder2`
```batch
`matlab -r \"run('C:\\folder1\\folder2\\main.m'); exit;\" -logfile log.txt`
``
Advantages:
Reliable and consistent output.
Handles most MATLAB scripts correctly.
This can handle interactive scripts also. But visually impaired people needs more attention because the MATLAB command window will not be read by the screen reader..
The `exit;` command ensures MATLAB closes cleanly.
Disadvantages:
The command string can become long if your script path is lengthy,
or if you want to pass arguments to your script (see below).
If your MATLAB script needs input arguments, you can pass them within the `-r` option.
```batch
matlab -r \"main(arg1, arg2); exit;\"
Example:
Suppose `main.m` is defined as:
```matlab
function result=main(a, b)
result = a + b;
disp(['The sum of ' num2str(a) ' and ' num2str(b) ' is ' num2str(result)]);
end
Then, you can execute it from the command line like this:
```batch
matlab -r \"my_script(5, 3); exit;\"
or using batch mode
matlab -batch main(3,4)
This will output:
The sum of 5 and 3 is 8
```
3. Using a batch script to simplify complex commands
Create a batch file (.bat) to avoid typing long commands repeatedly.
windows batch file auto.bat
```
@echo off
matlab -r \"run('main.m'); exit;\" -logfile log.txt
```
Save this as, say, `auto.bat` in the same folder of main.m, then just type `
If you type auto.bat in the CMD the main.m script will be executed.
4. Using a Callback Function for Output (More Advanced, for Specific Cases)
If your MATLAB script generates output using functions like `fprintf` or `disp`, the above methods should work fine. However, if you have more complex output requirements or are using graphics, you might need to consider more advanced techniques.
Redirecting Output in MATLAB Script: You can use `diary` command within your script.
```matlab
diary output.txt % Start recording output to output.txt
% Your MATLAB code here
diary off % Stop recording
```
Then, in the command window:
```batch
matlab -r \"run('your_script_name.m'); exit;\"
diary command is an alternat method to -logfile method. diary is within the script whereas -logfile used in the CMD.
5. Error Handling:
If your MATLAB script encounters an error, the command window might not show the complete error message. To get more detailed error information, consider these options:
Use `try...catch` blocks in your MATLAB script to handle potential errors and display more informative messages.
Redirect the standard error stream to a file:
```batch
matlab -r \"run('main.m'); exit;\" > error.txt
```
this is another alternate method todiary and logfile methods.
This will save any error messages to the `error.txt` file.
Displaying Figures:
If your MATLAB script creates figures, they will notbe displayed in the command window. They will appear in separate figure windows. If you need to save the figures, you can use the `saveas` command in your MATLAB script:
the main.m already having the code to save figures.
```matlab
figure(1);
plot(1:10);
saveas(gcf, 'my_plot.png', 'png'); % Save as PNG
```
Conclusion.
The batch mode is good for simple non interactive scripts. It is faster.
The `-r` option is generally the most reliable and recommended method for running MATLAB scripts from the command window and displaying the output. Remember to include `exit;` to ensure MATLAB closes properly.
Pay close attention to file paths and potential errors. ],
Discussions are welcome!!!. I published the powerflow solution by Halomorphic embedding (including PV) in my file exchange. Next post I will explain that. ),
As my sight becomes poor, I am using MATLAB with screen reader.
I published powerflow solution by Halomorphic embedding (including PV) IN THE FILE EXCHANGE. Next post I will discuss that code.
I explained how I used MATLAB to develop the script.
I will explain the script in my next post.
https://www. hmathworks.com/matlabcentral/fileexchange/180504-power-flow-solution-by-halomorphic-embedding-including-pv?s_tid=prof_contriblnk
I am trying my best to make MATLAB easier for the screen reader users like me.
Thank you.
RMS Danaraj
