<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">This was my original message to Joshua, but I wasn’t able to get it through to FLASH-USERS until today. I’m including it for posterity.</div><div class=""><br class=""></div><div class="">Hi Joshua,</div><div class=""><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div class=""><br class=""></div><div class="">First, based on what you posted from the Config and flash.par, you should have the particles inside the checkpoint files and the particle files. The reason you’re having trouble finding the particles in the files is because the way they are stored is not quite as obvious as is the case with the grid-based variables. </div><div class=""><br class=""></div><div class="">The particle data is stored in a HDF5 dataset called “tracer particles” at the top level of the HDF5 file. It is a two-dimensional array of double-precision floats in the shape of (number_of_particles, number_of_particle_attributes). The order of the attributes along that second axis can be found in the top-level dataset “particle names” in the same file. </div><div class=""><br class=""></div><div class="">Because things are laid out in this way, I would recommend trying to look at the particle data in yt, as it knows a bit more about the structure of FLASH files than VisIt does. </div><div class=""><br class=""></div><div class="">To load up a checkpoint file in yt, you can do it like this (these instructions are assuming yt version 3.0 or higher):</div><div class=""><br class=""></div><div class="">import yt</div><div class=""><br class=""></div><div class="">ds = yt.load(“name_of_my_checkpoint_file”)</div><div class=""><br class=""></div><div class="">Or, if you have a particle file that was dumped at the same time as a plot file, then you can do it this way:</div><div class=""><br class=""></div><div class="">ds = yt.load(“name_of_my_plotfile”, particle_filename=“name_of_my_particle_file”)</div><div class=""><br class=""></div><div class="">Then, you can look at the raw particle positions from the entire dataset by doing this:</div><div class=""><br class=""></div><div class="">dd = ds.all_data()</div><div class="">print dd[“particle_position_x”]</div><div class=""><div class="">print dd[“particle_position_y”]</div></div><div class=""><div class="">print dd[“particle_position_z”]</div></div><div class=""><br class=""></div><div class="">or the velocities:</div><div class=""><br class=""></div><div class=""><div class="">print dd[“particle_velocity_x”]</div><div class="">print dd[“particle_velocity_y”]</div><div class="">print dd[“particle_velocity_z”]</div></div><div class=""><br class=""></div><div class="">If you want to plot the positions, you can plot them over a slice of a grid variable such as “dens” like this:</div><div class=""><br class=""></div><div class="">slc = yt.SlicePlot(ds, “z”, “dens”) # Sliced along the “z” axis through the center of the domain</div><div class="">slc.annotate_particles(width) # for this you should replace width with the width of the slab you want</div><div class="">slc.save()</div><div class=""><br class=""></div><div class="">which will write a plot to disk. </div><div class=""><br class=""></div><div class="">For more information, check out the yt docs: <a href="http://yt-project.org/doc" class="">http://yt-project.org/doc</a></div><div class=""><br class=""></div><div class="">Any other questions, don’t hesitate to write back. </div><div class=""><br class=""></div><div class="">Best,</div><div class=""><br class=""></div><div class="">John Z</div></div></div></body></html>