Numerical Linear Algebra Packages on Linux

As a control engineer, I am always needing to use some numerical linear algebra software, usually Matlab or GNU Octave, but now that I have to write some C code using MPI for solving some linear algebra problems.
There are some software packages for that so.

Jochen Voss has a nice tutorial on BLAS and LAPACK at http://seehuhn.de/pages/linear

I was also googling around looking for something on sparse matrix with C. I've found this thread at a forum:
http://forums.aspfree.com/programming-help-33/c-initializing-a-sparse-matrix-236415.html

Comments

More trickery with gnuplot dumb terminal

In my post " Plotting memory usage on console " the chart doesn't pan the data. Now, using a named pipe, the effect got a little bit nicer. First, we have to run the memUsage.sh script to get a file filled with memory usage info: ./memUsage.sh > memUsage.dat & Then we have to create a named pipe: mkfifo pipe Now we have to run another process to tail only the last 64 lines from the memUsage.dat while [ 1 ]; do tail -64 memUsage.dat> pipe; done & And now we just have to plot the data from the pipe: watch -n 1 'gnuplot -e "set terminal dumb;p \"pipe\" with lines"' And that is it!

Replace transparency in PNG images with white background (for lots of files...)

I had to remove transparency from a PNG image file from the command line... and stack overflow came into my help[1]... But I needed it for lots of files... then, adding a "while read line" did the job: ls -1 *.png | cut -d . -f 1 | while read line; do convert -flatten $line.png flatten/$line.png ; done; [1] Replace transparency in PNG images with white background https://stackoverflow.com/questions/2322750/replace-transparency-in-png-images-with-white-background

Pettry rendered LaTeX equations using PHP

When I was writing a simple scientific webapp, during my undergrads studies, I needed to generate some equations to be shown by the app. I was already familiar with LaTeX equation formatting syntax, so I decided to use this nice peace of software. So, after "googling" a little, I found the imgtex , written by Koji Nakamaru , which is a fast CGI script, written in perl. What I did, was port it to PHP. To run it, you must have a LaTeX distribution and the dvipng software both installed on the same machine which you will run the PHP script. Here is the PHP code: To use this code, you just have to pass the LaTeX commands through GET to the PHP. For example, adding the following string to your URL: http://localhost/imgtex.php?res=300&cmd=x=\frac{-b\pm\sqrt{-4ac}}{2a} The res variable sets the resolution for the generated image and the cmd specifies the LaTeX command. This way, the above URL will produce the following image:

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