Hi people, today there is a very interesting post on a matlab central's blog. it describes how you can open a dialog to choose a file from the command line, and use it in some scripts.

the video is here.

enjoy!

## Wednesday, February 27, 2008

### open dialog to "open file" in matlab

Posted by otmezger at 8:20 AM 0 comments Links to this post

Labels: matlab

## Thursday, February 21, 2008

### calculate min/max in matlab excluding the zeros

the problem is how to calculate the minimum of a vector excluding the zeros?

here is an example how to do that:

Posted by otmezger at 10:06 AM 0 comments Links to this post

Labels: matlab

### about logical indexing

Today, M-Lint was telling me that "logical indexing is usually faster than FIND".

I didn't knew what logical indexing means. a short google search and i found this out:

if you want to perform the following operation:

you can optimize it just by omitting the find command just like this:

. Matlab is just capable to handle the "logical indexing" which means the indexes of the vector that match the conditions.

Posted by otmezger at 8:17 AM 5 comments Links to this post

Labels: m-lint, matlab, speeding up code

## Tuesday, February 19, 2008

### how to turn a matrix into a single vector with matlab

hi, if you are trying to transform a matrix into a single vector you sould't use if's.

there is a very easy way to do that.

if your matrix a = [1 2 3; 4 5 6], the command b=a(:) will generate a matrix b that looks like this: [1 4 2 5 3 6]'

Posted by otmezger at 11:44 AM 0 comments Links to this post

Labels: matlab

## Tuesday, February 12, 2008

### use profiler to improve code

there is a very cool application in matlab to help you improve the code. it is called "profiler".

let me give you an example. If you have a script named "name_of_script.m", you can enter the following commands to check it:

at the end, you'll get a new windows, where you can find which section of the script is the bottleneck.

happy coding!

Posted by otmezger at 12:54 PM 0 comments Links to this post

Labels: matlab, speeding up code

### improving matlab code to run faster

improve matlab code to run faster... that's the question. i found a very cool document on the web. you can find it here.

Posted by otmezger at 11:59 AM 0 comments Links to this post

Labels: matlab-tutorials

### List of Matlab tutorials and Howtos

Great list of matlab tutorials and howtos.

you can find it here

Posted by otmezger at 10:30 AM 0 comments Links to this post

Labels: matlab, matlab-tutorials

## Saturday, February 9, 2008

### function in matlab to convert 1/4-h vectors to 1-h vector

sometime i have to handle with large data vectors, which are time measurements. One value each 15 Min.

For the analysis, i can use 1 value per hour. to convert the vectors i use the following function:

function DATout = convert_15min_1h(DATin)

size_15min=length(DATin);

size_1h=size_15min/4;

DATout=zeros(size_1h,1);

for i=1:1:size_1h

von=(i-1)*4+1;

bis=(i)*4;

DATout(i)=sum(DATin(von:bis))/4;

end

Posted by otmezger at 9:08 AM 0 comments Links to this post

Labels: matlab

## Friday, February 8, 2008

### Zeilenabstand in LaTeX

um in LaTeX den Zeilenabstand zu ändern, z.b. von 1,5 auf 1,0 oder sogar 1,25, benutzt man diesen Kommando im prämble:

Posted by otmezger at 4:18 PM 0 comments Links to this post

Labels: latex