Creating movies from multiple jpg picture files

In my research, I produced a number of figures of time sequences. And I wanted to create a movie from this multiple jpg files. I use mencoder to do this, to install type:
sudo apt-get install mencoder (if you are using debian based such as ubuntu)
Then to create the avi file, simply type:

mencoder mf://@list.txt -mf fps=5:type=jpg [...]

Why the sky is blue

If you don’t know why the sky is blue, you may want to read up this article:
Blue Sky
It is interesting and shows some physics of absorption and emission of light in day to day things you can see.

Changing background and front color in plplot library

The default background color in plplot library is black while the frontcolor is red. To do this, use plscolbg and plcol0 function. The code in fortran is:

call plscolbg(255,255,255)
call plinit()
call plcol0(8)

Remember that plscolbg must be called before plinit. The above code change the background color to white (rgb=255,255,255) and the front color to brown (8, refer [...]

Kubuntu 9.10 is shining

I have been using Ubuntu 9.04 since it just works. The previous version of Kubuntu is pretty difficult to use. When using ubuntu, everything just works, I can watch video streaming, plugin downloaded autmatically, etc, etc.
So recently I have upgraded to 9.10, and I am so impressed with KDE 4. At least now the [...]

Obtaining clock time using Fortran

to get the current time in Fortran, we can use “system_clock” built-in function. To do this, take a look at the code below.

integer::count_0,count_rate,count_max, walltime, tstart,tend
call system_clock(count_0,count_rate,count_max)
tstart=count_0/count_rate
write(*,*) ‘begin (system_clock)’,tstart

To find out how long your program has run, add a similar line and save the time to, for example “t_end” variable, and get the difference. It will [...]

Debugging OpenMP fortran code

As the code becomes parallel, the complexity increases. One of the common problem in parallel code is data race. To debug this problem, I encounter that Intel’s Thread Checker to be a good software. You can download from the Intel’s website for evaluation. I found about this when I read this article
When I run [...]

VTK error reading ascii data! when writing using Fortran

I write a fortran code and save the data in VTK legacy format with structured points. However, for certain data somehow Paraview and Mayavi are unable to read the VTK file. It gives a “Generic Warning”, and says that
Error reading ascii data!
After days of debugging, it turns out that the cause is my precision, I [...]

How to embed fonts when using pdflatex and gnuplot

IEEE require that PDF documents are created with embedded fonts. To do this, run

$ updmap –setoption pdftexDownloadBase14 true

And then run pdflatex again. To check whether it is embedded, run pdffonts on to the newly created pdf. You will see something like this.

$ pdffonts draft_isic2009_1.pdf
name [...]

Installing Octave 3.2.3 in Kubuntu Hardy

Octave has released a major version 3.2 and now the latest bug fix release is 3.2.3. I decided to install it. What I did was to download the tarball from www.octave.org and then unzip it. After that, I run the configure:

./configure –prefix=$HOME/Programs/Octave-3.2.3

where the prefix defines the location where to install the new version of octave. [...]

Debugger for Fortran in Linux

I have been trying to search for a good debugger for Fortran code in Linux. But it is very hard to find. I know that GDB is supposed to be able to do it. But when I debug Fortran 95 code compiled using GFortran, I simply don’t know how to display the dynamic size array. [...]