Can someone either point me to an online/free MATLAB compiler/interpreter or explain what happens in this MATLAB code?

Question

I apologize in advance for this question. I don't like "explain this code" questions, but I can't find any documentation about my specific example.

Background
My issue is this. I am trying to translate some MATLAB code to C#, but I am at the same time having to learn MATLAB. I do not work with anyone that knows MATLAB code, I have no access to MATLAB, so I can't test any of the code, and I can't find any documentation on the following question. So...

Question(s)

1. Is there a free online/desktop MATLAB compiler/interpreter somewhere that I can use to test out MATLAB code?

   ...or...

2. Is there someone that can explain the following code snippet:

   someVar.member1=myValue1;
   someVar.member2=myValue2;
   if (myCondition)
       for i=1:myTotal
           someVar(i).member3=myValue3;
       end;
   end;
   

   Does this make someVar into an array? Do I lose member1 and member2 or does it save what I have set somehow?

Rains

You can try this on: gnu.org/software/octave its matlab clone and free to use. Most of matlab code work here. – Backpack

This and this are two "okay" online Octave terminals. Note that both do not support the entire variety of MATLAB's built-in commands. – Kick

For you first question, you could try MATLAB Online: matlab.mathworks.com – Kapp

Answer 1

Re: 1 - There is the excellent Matlab Documentation, including video tutorials, which will help you understand Matlab. This is much more useful than a compiler, since you'll learn what the code intended, so that you can re-write it in a fashion that is appropriate for C#, rather than trying to copy Matlab-optimized syntax.

However, to test-run Matlab code, there is Octave which provides most of the functionality of core Matlab, but may not support toolbox functions (additional modules of Matlab that you pay for extra).

Re: 2 - Here's what the code does

Instantiate a structure array someVar (Matlab doesn't need declaring variables beforehand) with a field member; assign it to myValue1

someVar.member1=myValue1;

Create an additional field member2, set it to myValue2

someVar.member2=myValue2;

If the condition is true, loop myTotal times, and set the field member3 of all i elements of someVar to myValue3. Thus, someVar goes from a 1-by-1 structure array to a 1-by-myTotal structure array. someVar(1).member1 remains myValue1, while someVar(i).member1 are initialized to empty ([]).

if (myCondition)
    for i=1:myTotal
        someVar(i).member3=myValue3;
    end;
end;

/aside: This loop is a rather inefficient way to define the structure. So there may not be much Matlab-optimized syntax in the code you need to translate.

Macaw

Definitely inefficient. Not fun code to translate. Thanks for the link and the explanation. – Rains

@MikeWebb: There are also Matlab blogs, particularly Loren's, that talk about some interesting/curious aspects of Matlab. Also, there's us here, or the folks over at Matlab Answers, who're always glad to help you understand code (unless it makes my eyes bleed. I don't like when my eyes bleed). – Macaw

Answer 2

I've written a free online interface for MATLAB/Octave that runs scripts and also has a live prompt where you can type commands. You can also save your scripts between sessions. Check it out at octave-online.net.

Connolly

Answer 3

1. You can try Octave, which is free and pretty compatible with MATLAB.

2. At the end of this snippet (assuming myCondition is true), someVar will be a vector with length myTotal (i.e. an array of size 1 by myTotal). Each element of the vector will be a structure with three fields member1, member2 and member3. The first element of the vector will have values for all three fields; the remaining ones will have values only for member3, and will have the empty array as values for member1 and member2. If myCondition is false, you'll have single structure with two fields member1 and member2.

Hope that helps!

Veterinarian

Thanks for the explanation and the suggestion for Octave. I will check it out. – Rains

Answer 4

Try this website:
http://www.compileonline.com/execute_matlab_online.php
It has a Matlab compiler as well as many other languages such as Perl, Python, Java, C, etc.

Basrhin

This is an Octave compiler, not a Matlab compiler. They are not 100% compatible – Wildermuth

Answer 5

I just want to reiterate one of the suggested choice: anycodex.com in a previous answer, because it wasn't mentioned that it's an actual online MATLAB interpreter, which is really nice. I was suspicious at first, thinking that it was just another one powered by Octave, but after using ver command it seems to show that it uses MATLAB Version: 7.14.0.739 (R2012a) as seen here with its installed products:

--------------------------------------------------------------------------------------------------
MATLAB Version: 7.14.0.739 (R2012a)
MATLAB License Number: 161052
Operating System: Linux 3.5.0-23-generic #35~precise1-Ubuntu SMP Fri Jan 25 17:15:33 UTC 2013 i686
Java Version: Java 1.6.0_17-b04 with Sun Microsystems Inc. Java HotSpot(TM) Client VM mixed mode
--------------------------------------------------------------------------------------------------
MATLAB                                                Version 7.14       (R2012a)
Simulink                                              Version 7.9        (R2012a)
Aerospace Blockset                                    Version 3.9        (R2012a)
Aerospace Toolbox                                     Version 2.9        (R2012a)
Bioinformatics Toolbox                                Version 4.1        (R2012a)
Communications System Toolbox                         Version 5.2        (R2012a)
Computer Vision System Toolbox                        Version 5.0        (R2012a)
Control System Toolbox                                Version 9.3        (R2012a)
Curve Fitting Toolbox                                 Version 3.2.1      (R2012a)
DO Qualification Kit                                  Version 1.6        (R2012a)
DSP System Toolbox                                    Version 8.2        (R2012a)
Database Toolbox                                      Version 3.11       (R2012a)
Datafeed Toolbox                                      Version 4.3        (R2012a)
Econometrics Toolbox                                  Version 2.1        (R2012a)
Embedded Coder                                        Version 6.2        (R2012a)
Filter Design HDL Coder                               Version 2.9.1      (R2012a)
Financial Derivatives Toolbox                         Version 5.9        (R2012a)
Financial Toolbox                                     Version 4.2        (R2012a)
Fixed-Income Toolbox                                  Version 2.3        (R2012a)
Fixed-Point Toolbox                                   Version 3.5        (R2012a)
Fuzzy Logic Toolbox                                   Version 2.2.15     (R2012a)
Global Optimization Toolbox                           Version 3.2.1      (R2012a)
HDL Coder                                             Version 3.0        (R2012a)
HDL Verifier                                          Version 4.0        (R2012a)
IEC Certification Kit                                 Version 2.1        (R2012a)
Image Acquisition Toolbox                             Version 4.3        (R2012a)
Image Processing Toolbox                              Version 8.0        (R2012a)
Instrument Control Toolbox                            Version 3.1        (R2012a)
MATLAB Builder JA                                     Version 2.2.4      (R2012a)
MATLAB Coder                                          Version 2.2        (R2012a)
MATLAB Compiler                                       Version 4.17       (R2012a)
MATLAB Distributed Computing Server                   Version 6.0        (R2012a)
MATLAB Report Generator                               Version 3.12       (R2012a)
Mapping Toolbox                                       Version 3.5        (R2012a)
Model Predictive Control Toolbox                      Version 4.1        (R2012a)
Neural Network Toolbox                                Version 7.0.3      (R2012a)
Optimization Toolbox                                  Version 6.2        (R2012a)
Parallel Computing Toolbox                            Version 6.0        (R2012a)
Partial Differential Equation Toolbox                 Version 1.0.20     (R2012a)
Phased Array System Toolbox                           Version 1.2        (R2012a)
RF Toolbox                                            Version 2.10       (R2012a)
Robust Control Toolbox                                Version 4.1        (R2012a)
Signal Processing Toolbox                             Version 6.17       (R2012a)
SimBiology                                            Version 4.1        (R2012a)
SimDriveline                                          Version 2.2        (R2012a)
SimElectronics                                        Version 2.1        (R2012a)
SimEvents                                             Version 4.1        (R2012a)
SimHydraulics                                         Version 1.10.1     (R2012a)
SimMechanics                                          Version 4.0        (R2012a)
SimPowerSystems                                       Version 5.6        (R2012a)
SimRF                                                 Version 3.2        (R2012a)
Simscape                                              Version 3.7        (R2012a)
Simulink 3D Animation                                 Version 6.1        (R2012a)
Simulink Code Inspector                               Version 1.1        (R2012a)
Simulink Coder                                        Version 8.2        (R2012a)
Simulink Control Design                               Version 3.5        (R2012a)
Simulink Design Optimization                          Version 2.1        (R2012a)
Simulink Design Verifier                              Version 2.2        (R2012a)
Simulink Fixed Point                                  Version 7.1        (R2012a)
Simulink Report Generator                             Version 3.12       (R2012a)
Simulink Verification and Validation                  Version 3.3        (R2012a)
Stateflow                                             Version 7.9        (R2012a)
Statistics Toolbox                                    Version 8.0        (R2012a)
Symbolic Math Toolbox                                 Version 5.8        (R2012a)
System Identification Toolbox                         Version 8.0        (R2012a)
SystemTest                                            Version 2.6.3      (R2012a)
Wavelet Toolbox                                       Version 4.9        (R2012a)

Very nice find indeed. Cheers.

Flotsam

Link redirects to a porn site. – Rocambole