<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">HI Owen,<div><br></div><div>I’m a newbie too, but I ran across the following while learning about FLASH:</div><div><br></div><div>if you have 7 mgd groups, if you look at the “lasslab_hdf5_chk****” “check point” file that is force dumped, it contains ALL FLASH variables, in addition to the ones you requested to be plotted in the “plot_var” statements that are specified in the *.par file you’re using to set up.</div><div><br></div><div>There should be variables named r001, r002, r003, … r00N up to the number of MGD groups N, which are specific radiation energy in each group (ergs/g).</div><div><br></div><div>If you want those at each plot dump, you could declare them in the *.par file as “plt_var” like the other variables. Or you can specify the force dump time intervals by modifying:</div><div><br></div><div><div>### Checkpoint Options ###</div><div>checkpointFileIntervalTime = 1.0</div><div>checkpointFileIntervalStep = 1000</div><div><br></div><div>David Montgomery</div><div><br></div><div><br></div><div><blockquote type="cite"><div>On Jul 11, 2025, at 9:58 AM, Owen Bardeen <owenbardeen@gmail.com> wrote:</div><br class="Apple-interchange-newline"><div><div dir="ltr">Just to provide some more context in case it's helpful:<div><br></div><div>I am using FLASH version 4.7.1, with the LaserSlab module. I have 7 mgd groups, as outlined in my .par file:</div><div>rt_useMGD = .true.<br>rt_mgdNumGroups = 7<br></div><div><br></div><div>It seems to me that FLASH must store information about radiation transfer in each group somewhere. I'm looking in FLASH4.7.1/source/physics/RadTrans/RadTransMain/MGD but it's not obvious to me where it's stored. It would be nice if I could just add it as a variable to flash.par to be included in the output files, but if I have to dig into the Fortran that's fine too. </div><div><br></div><div>If someone could point me in the right direction it would be much appreciated.</div><div><br></div><div>Thank you!</div><div>Owen</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Jul 9, 2025 at 3:30 PM Owen Bardeen <<a href="mailto:owenbardeen@gmail.com" target="_blank">owenbardeen@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Hello all,<div><p>I’m currently working on a simulation involving radiative transport in a hot plasma using the FLASH code (v4.7.1). I’m interested in quantifying the radiative emission, with the capability of comparing radiative emission from different energy groups (0.1-1 eV, 1-10 eV, etc.). </p><p>My question is: what is the best way to determine the total radiative output, as well as from one specific energy bin/group, from FLASH output?</p><p>I’ve generated the necessary Propaceos opacity tables with a dedicated energy group covering just this narrow range. </p><p>If anyone has experience extracting radiative output from individual bands in FLASH, I’d greatly appreciate your guidance.</p><p>Thank you!</p><p>Owen Bardeen</p><p>University of California, San Diego</p></div></div>
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