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I recently dug out some old half finished work about using DTrace to study numerical algorithms complexity and thought that it would make a nice post. Although the technique of tracing function calls to identify an algorithm complexity class empirically is not new, I've never seen it done using DTrace. In this entry I show how, by using DTrace, to analyze algorithms written using MPFR (or GMP). I also included an example application for a simple well-known algorithm acting as a proof of concept. After all, a blog post about numerical computing without some graphs would be a shame.

I would like to invite everyone to read this great forum post by Dennis Clarke the CEO of Blastwave.org on the OpenSolaris mailing list.

Message by Dennis Clarke about the status of the primary mirror and the future of Blastwave.org

From all the open source softwares in existence I do not think that any single one gathers as much “How to build X on Y” articles than GCC. When considering some of the intricacies of Solaris it's not surprising to see that Solaris gets his fair share of those articles. I however came to the conclusion that one more was needed, for a few reasons that I would like to explain before moving on. First, nearly all of the blogs and articles I read on the subject were very good, but they are not aimed at beginners.

OpenSolaris is my primary desktop operating system since the first official release 2008.05. Since then I get a lot of funny, horrified or sarcastic comments about my choice of OS. Those comments or naive questions can generally be resumed by one of the following sentences :

1. Wow! Which version of Windows is that? (90% of the remarks)
2. Oh you are using a Mac! (A small subset of the population of remark 1 falls here)
3. Why don't you use Linux? (98% of the people at the GSOC mentor summit)
   

Plenty of information is available for setting up an AMP stack on different flavours of Linux and even MS Windows. Some good quality guides are also available from Sun for setting up the Sun AMP stack on Solaris and OpenSolaris. This blog entry, presents a simple step-by-step guide on how to install and setup a high performance AMP stack from Blastwave.org.

Quite a while ago I tried installing Solaris 9 in VirtualBox 2.1.4, which sadly failed miserably. A quick look at the bug database shown that there was some known issues with Solaris 9 and that at that time it was impossible to make it work under VirtualBox. A bit sad since virtual machines are a great way to test and develop for many legacy operating systems at the same time. But things have changed! A recent comment on the bug report in question asked if Solaris 9 was working with VBox 3.0.6.

I found myself having to test some OpenMPI code recently, and needed a small cluster for the task. Performance wasn't really an issue for those tests since only the correctness of the code was important. Generally, in those situations where I need to test something quickly in an isolated environment I use VirtualBox or a Solaris zone. So I thought, why not here also.