Posts Tagged ‘GADGET’

More Images & a New MakeGalaxy Code

Sunday, February 5th, 2012

I have had some more time to struggle with practice using Sunrise now. I’ve managed to sucessfully run the radiative transfer on several GADGET-2 snapshots of merging systems. This required me to make a minor edit to the code.  There was a seemingly arbitrary speed limit in the code which caused it to exit if any particles moved faster than 1000 km/s. I had to increase the speed limit in order to prevent the code from exiting.  I’ve contacted Patrik to see if there was a technical reason for the 1000 km/s speed limit. I wouldn’t want to break anything.  The code has now been recompiled with CUDA support.  The CUDA version runs noticeably faster, as expected.

In other news, T.J. Cox just made the MakeGalaxy code public on Bitbucket. Someone has uploaded a new flexible version of CombineGalaxies to Bitbucket as well. To download the Mercurial repositories use: (more…)

First Simulations

Tuesday, November 8th, 2011
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…)

Paper in preparation, P-GADGET-2, & Git

Monday, February 21st, 2011
Last week I finally obtained a copy of the full-physics version of GADGET-2.  According to Desika Narayanan, it’s a version which has been verified to work with Sunrise. Once I’m no longer busy with other things, I’ll start working with it. I have almost finished writing a cycle 19 HST theory proposal. The deadline is in a few days. I’m in the early stages of working on a paper describing my qualifier project.  After reading through the literature from the last 34 years and thinking about the deficiencies in my project as it stands, I’ve decided to further modify the code to include several more features.  Yesterday I wrote an energy tracking function and I’ve begun writing a density profile plotter.  I’ve also improved the performance of the code somewhat.  Functions for plotting the line-of-sight velocity distribution and for computing the skewness of the distribution will be added shortly.  I may also try writing a hierarchical time-stepping scheme to improve performance further. I’ve decided to maintain the qualifier code using a revision control system.  I’ve used Subversion for projects in the past, but Mercurial and Git seemed to be much better options.  I ultimately decided to use Git. Git Tutorial,  Git Manual Git should also come in handy when collaborating on LaTeX documents.