The first paper to result from research described in this web log has been published in The Astrophysical Journal. The paper is “The Evolution of Stellar Velocity Dispersion During Dissipationless Galaxy Mergers”     Links to the paper: Official DOI   |   ADS   |   ArXiv.org

After spending quite a bit of time moving to a new apartment (cleaning, packing, moving, more cleaning, and unpacking), I have had time to try using Patrik Jonsson’s Sunrise code.  The instructions on the Sunrise wiki were quite helpful. I ran into very few problems in the process. The biggest “problem” was a minor bug that took two minutes or so to figure out; the code requires the environment variable HOST to be defined. The code tries to handle the possibility that the name of the host computer is stored in the variable HOSTNAME (the default situation in Ubuntu), but there’s a problem with the implementation: (more…)

I have finally managed to compile the latest (default) version of Sunrise! I had to tinker with it periodically over the course of a few days, but I finally managed to do it.  The current version of the code in the Mercurial repository has evidently been designed to compile only with Arepo support, but I do not have Arepo and I will not be using Arepo for my project.  It seems that compiling the code without Arepo is planned, but not fully implemented in the current version.  There are several errors that occur when Arepo is absent.  In order to get the code to compile, I had to extensively edit the pre-processor directives.

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Several months have passed since I last wrote a research log entry.  I should probably write these a bit more frequently.  Much has happened since the previous entry!

• My HST Cycle 19 Theory proposal was accepted and all of requested funding has been provided!
• I became the first physics graduate student at UCR to be an instructor for a course (rather than just a teaching assistant). I taught Physics 40A during the summer session.
• I got married!
• I finished writing my first paper.  The paper is still being reviewed as I write this, so it’s technically not finished because it hasn’t been revised, resubmitted, and accepted for publication yet.
• I compiled P-GADGET-2 and ran several small simulations on Crunch.
• I’ve written a code in C++ to read, analyze, manipulate, and output GADGET-2 snapshot files. The code is very basic at the moment, but it should be mostly finished in a few months. I’ll use this code for the non-Sunrise component of my thesis project. I plan to write another research log entry describing the first application of the code: quadratic spline interpolation of snapshot files for purposes of making animations.
• I’ve built a GADGET-aware version of IFrIT.  This was somewhat more time-consuming than it should have been since there were no explicit instructions on how to build the GADGET plugin into IFrIT. I also managed to get SPLASH to read and analyze / visualize my GADGET-2 snapshots.  I still haven’t managed to get Splotch to read my snapshot format though…I’m going to move on to working with Sunrise now.  I’ve heard that successfully building Sunrise takes some effort.
• I’ve started reviewing the core of theoretical physics and I’ve finally started learning some elementary particle physics / quantum field theory. (more…)

Dr. Gillian Wilson, one of my thesis committee members, was kind enough to provide me with funding to build a workstation for my project. I needed a fast shared memory machine with at least 32 GB of RAM in order to run Sunrise efficiently. After configuring several systems on the HP, Dell, Apple, and other websites, I discovered that it would be considerably more cost-effective if I designed and built the machine myself. Ideally, I would have built a system consisting of 2 or 4 of Intel’s latest Xeon processors and an Nvidia Tesla c2050 card, but I tried to keep the price as low as possible for the level of performance necessary.  I eventually obtained the following combination of components:

Motherboard:	Asus KGPE-D16 Dual Socket G34 AMD SR5690 SSI EEB 3.61
Processors:	2x AMD Opteron 6172 Magny-Cours 2.1 GHz  (24 cores total)
Memory:	16x 4 GB DDR3 1333 unregistered DRAM (64 GB total)
Graphics:	EVGA Nvidia GeForce GTX 580 (containing 512 CUDA cores and 1.5 GB GDDR5 )
System disk:	64 GB Crucial RealSSD C300
Data disks:	2x 1.0 TB Western Digital Caviar Black WD1002FAEX
Chassis:	Intel 5U Server Chassis SC5650WSNA, with 1000W PSU

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