Distributed Hadoop and HBase installation - Fedora Linux
In this post I will describe how to get started with the latest versions of hadoop and hbase describing all the step to obtain a working hadoop installation. The steps described here can be easily used to perform a working installation on a large cluster (even tough it can requires additional steps as shared filesystem for instance).
This article present a CUDA parallel code for the generation of the famous Julia Set. Informally a point of the complex plane belongs to the set if given a function f(z) the serie does not tend to infinity. Different function and different initial condition give raise eventually to fractals. One of the most famous serie is (the one that generated the video below).
Some nice picture may be obtained with the following initial conditions:
# dentrite fractal
# douady's rabbit fractal
# san marco fractal
# siegel disk fractal
# NEAT cauliflower thingy
Here a video, showing a sequence of picture generated using different initial conditions. A nice example of how math and computer science can produce art!
CUDA Julia set code
The code is such that it is very easy to change the function and the initial condition (just edit the device function functor).
The code above are the GPU instructions that are devoted to the computation of a single set. The kernel computeJulia() is executed on DIMX*DIMY (the dimension of the image) threads that indipendently compute the evolveComplexPoint() function on the converted to complex corrensponding pixel indices, the viewport (each threads compute a single pixel that has integer coordinates). The evolveComplexPoint() take care of checking how fast che point diverges.
The code is available here on github. It generates a number of png tha can be then merged in a video (as the one I present here) using a command line tool as ffmpeg.
In order to compile and run it need the CUDA SDK,a CUDA capable device and libpng installed on your system.
To compile and/or generate the video simply hit:
Linux Kernel especially in the past years was plenty of different and replicated implementation of generic data structures such as linked lists, stacks and queues. Kernel's developers decided to provide a unique set of API for using these kind of software machineries. We will briefly look in this article at the list.h file (in the linux source tree under /usr/src/linux-headers-`uname -r`/include/)that provides macros and function for utilizing a doubly linked circular list. It is a very smart written piece of code that is worth to take a look at as it is an opportunity to improve C programming skills and at the same time to see an "unconventional" implementation for a common data structure.
From canonical list to Linux kernel linked list
The canonical implementation of a C's linked list consists of a structure and two (for a doubly linked) recursive pointer fields to the structure itself. The links to the previous and subsequent element of the list.
struct point2DNode* prev, next;
Finally at my Departement we succesfully converted an unsed Apple xserve cluster to a full functional Linux/Debian machine.
The cluster is make up of eleven node connected by Myrinet 10G low latency network and each node is a composed by a dual 4x cores Intel Xeon 2.8 Ghz Harpertown with 10Gb of DDR2 for a total of 88 cores. It is a quite old and small machine and hence was unused. We thought that it could have been useful if well re-configured as an ad-hoc machine for small sized scientific computation session, as developing and testing platform of parallel application or for training of undergraduate students that can experience directly with a real parallel machine. So we decided to cast a new light on it by configuring it as a Debian cluster (according to google just few people did it).