Tag Archives: matlab

Matlab compiler installation. If you have trouble after installation of Microsoft Windows SDK 7.1

Solution for the Matlab compiler installation. If you have trouble after installation of Microsoft Windows SDK 7.1

Today I am writing a tip to solve a Matlab compiler setup problem. 

If you want to use MEX or any Matlab compiling technology, you need a compiler. Windows does not have a default compiler. So you have to install. If you don’t have any compiler, you would see the below message.

>> mex -setup

Welcome to mex -setup. This utility will help you set up 
a default compiler. For a list of supported compilers, see 
http://www.mathworks.com/support/compilers/R2013a/win64.html 

Please choose your compiler for building MEX-files: 

Would you like mex to locate installed compilers [y]/n? y

No supported SDK or compiler was found on this computer. 
For a list of supported compilers, see 
http://www.mathworks.com/support/compilers/R2013a/win64.html 

Error using mex (line 206)
Unable to complete successfully.

If you follow the link, you can install “Microsoft Windows SDK 7.1″

BUT, IMPORTANT, if you don’t have “.NET Framework 4.0,” you cannot install the compiler. As shown in the below figure, you MUST install .NET Framework 4.0 for installation of the windows compiler.

Matlab compiler problem, if you have trouble after the installation of Microsoft Windows SDK 7.1

Matlab compiler problem, if you have trouble after the installation of Microsoft Windows SDK 7.1

Then, I wish this post can help to solve your problem.

Thank you.

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I am Youngmok Yun, and writing about robotics theories and my research.

My main site is http://youngmok.com, and Korean ver. is  http://yunyoungmok.tistory.com.

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Parallel computation with Matlab, SPMD. Explanation with simple example code

Today I’d like to introduce a parallel computation skill in Matlab.

I also heard that the use of parallel computation in Matlab is very easy. But it was better than my expectation. Wonderful!! Smile

You need to know the usage of SPMD. It is pretty easy.

First let’s the code, you can also download this file in the attachment, click <here>.
parallel_computation_spmd

 

The result is the below

Starting matlabpool using the ‘local’ configuration … connected to 4 labs.
Elapsed time is 120.482356 seconds.
Sending a stop signal to all the labs … stopped.
Elapsed time is 167.796932 seconds.

Because, I did many other works in the calculation time, Its result is not very fast, The slowest CPU core determined the final computation time. But its performance is really good if you have more than 4 multi cpu cores.

I wish this post can help your understanding about the use of SPMD in Matlab.

if you have any question, please leave me a comment below.

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I am Youngmok Yun, and writing about robotics theories and my research.

My main site is http://youngmok.com, and Korean ver. is  http://yunyoungmok.tistory.com.

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Phase plane analysis and Matlab code toolbox

Phase plain analysis is a useful visualization tool to understand the characteristics of systems including not only linear system but also nonlinear system. For example, we can determine stability of the system from this phase plane analysis.

The attachment file <here> is Matlab toolbox to draw phase plain. The attached file includes a simple demo and the below is the result. You can draw phase plane, magnify where you are interest recursively. You can see how to use the Matlab code in the following Youtube video.

demo_phase_plane

    

How to draw?

Given,

\dot{x}_1=f_1(x_1,x_2)

\dot{x}_2=f_2(x_1,x_2)

we can find the below equation

\frac{dx_2}{dx_1}=\frac{f_2(x_1,x_2)}{f_1(x_1,x_2)}

From \frac{dx_2}{dx_1}, we can find the direction of the phase change at the point of (x_1, x_2).

 

Advantage:

  1. It is an exact method. We can see the change of system’s state including transient response.
  2. Simple graphical method. It is very intuitive and easy to understand its characteristics.

Limit:

  1. Limited to the 2nd order system. It is expandable, but hard to visualize. 

Reference

1. Lecture of Prof. Fernadez in Mech. Eng, The Univ. of Texas at Austin.