Hi all, I’m trying to load a cosmological snapshot from a Changa simulation (which I believe is in the tipsy format). Yt seems to find some of the cosmological parameters but not all of them (not the hubble constant), which messes up the units. See below. There is some discussion of cosmology parameters and tipsy format in the docs, but I did not understand it. Can anyone with experience loading this format give me some pointers? Thanks Christine In [1]: pf = load('agora_1e11q_l13.000400') yt : [INFO ] 2016-11-03 15:17:47,253 Parameters: current_time = 1.61048087203e+23 s yt : [INFO ] 2016-11-03 15:17:47,253 Parameters: domain_dimensions = [2 2 2] yt : [INFO ] 2016-11-03 15:17:47,254 Parameters: domain_left_edge = [-0.5 -0.5 -0.5] yt : [INFO ] 2016-11-03 15:17:47,255 Parameters: domain_right_edge = [ 0.5 0.5 0.5] yt : [INFO ] 2016-11-03 15:17:47,256 Parameters: cosmological_simulation = 1.0 yt : [INFO ] 2016-11-03 15:17:47,256 Parameters: current_redshift = -1.48991929905e-13 yt : [INFO ] 2016-11-03 15:17:47,256 Parameters: omega_lambda = 0.728 yt : [INFO ] 2016-11-03 15:17:47,256 Parameters: omega_matter = 0.272 yt : [INFO ] 2016-11-03 15:17:47,256 Parameters: hubble_constant = 1.89812815754e-06
Hi Christine, There are some assumptions made by yt when loading data from gasoline or changa about whether a simulation is run with comoving coordinates or physical ones. I developed the tipsy frontend mostly working from gasoline outputs, but it should work for changa too (in other words, I think you may have found a bug). Would you be able to upload the parameter file you are using for this? Judging from your file name, I assume you are running one of the agora cosmological runs? Ben On Thu, Nov 3, 2016 at 8:35 PM, Christine Simpson <christine.simpson@gmail.com> wrote:
Hi all,
I’m trying to load a cosmological snapshot from a Changa simulation (which I believe is in the tipsy format). Yt seems to find some of the cosmological parameters but not all of them (not the hubble constant), which messes up the units. See below. There is some discussion of cosmology parameters and tipsy format in the docs, but I did not understand it. Can anyone with experience loading this format give me some pointers?
Thanks Christine
In [1]: pf = load('agora_1e11q_l13.000400') yt : [INFO ] 2016-11-03 15:17:47,253 Parameters: current_time = 1.61048087203e+23 s yt : [INFO ] 2016-11-03 15:17:47,253 Parameters: domain_dimensions = [2 2 2] yt : [INFO ] 2016-11-03 15:17:47,254 Parameters: domain_left_edge = [-0.5 -0.5 -0.5] yt : [INFO ] 2016-11-03 15:17:47,255 Parameters: domain_right_edge = [ 0.5 0.5 0.5] yt : [INFO ] 2016-11-03 15:17:47,256 Parameters: cosmological_simulation = 1.0 yt : [INFO ] 2016-11-03 15:17:47,256 Parameters: current_redshift = -1.48991929905e-13 yt : [INFO ] 2016-11-03 15:17:47,256 Parameters: omega_lambda = 0.728 yt : [INFO ] 2016-11-03 15:17:47,256 Parameters: omega_matter = 0.272 yt : [INFO ] 2016-11-03 15:17:47,256 Parameters: hubble_constant = 1.89812815754e-06
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Hi Christine, You can load tipsy data with specified cosmological parameters like this: cosmology_parameters = {'current_redshift': 0.0, 'omega_lambda': 0.728, 'omega_matter': 0.272, 'hubble_constant': 0.702} ds = yt.load(tipsy_filename, cosmology_parameters=cosmology_parameters) (in general the load function can take any of the keyword arguments accepted by the TipsyDataset class defined in yt/frontends/tipsy/data_structures.py) You're right that the docs should state this explicitly. I've issued a pull request to update the docs here: https://bitbucket.org/yt_analysis/yt/pull-requests/2431 -Nathan On Thu, Nov 3, 2016 at 11:02 PM, B.W. Keller <kellerbw@mcmaster.ca> wrote:
Hi Christine,
There are some assumptions made by yt when loading data from gasoline or changa about whether a simulation is run with comoving coordinates or physical ones. I developed the tipsy frontend mostly working from gasoline outputs, but it should work for changa too (in other words, I think you may have found a bug). Would you be able to upload the parameter file you are using for this? Judging from your file name, I assume you are running one of the agora cosmological runs?
Ben
On Thu, Nov 3, 2016 at 8:35 PM, Christine Simpson <christine.simpson@gmail.com> wrote:
Hi all,
I’m trying to load a cosmological snapshot from a Changa simulation (which I believe is in the tipsy format). Yt seems to find some of the cosmological parameters but not all of them (not the hubble constant), which messes up the units. See below. There is some discussion of cosmology parameters and tipsy format in the docs, but I did not understand it. Can anyone with experience loading this format give me some pointers?
Thanks Christine
In [1]: pf = load('agora_1e11q_l13.000400') yt : [INFO ] 2016-11-03 15:17:47,253 Parameters: current_time = 1.61048087203e+23 s yt : [INFO ] 2016-11-03 15:17:47,253 Parameters: domain_dimensions = [2 2 2] yt : [INFO ] 2016-11-03 15:17:47,254 Parameters: domain_left_edge = [-0.5 -0.5 -0.5] yt : [INFO ] 2016-11-03 15:17:47,255 Parameters: domain_right_edge = [ 0.5 0.5 0.5] yt : [INFO ] 2016-11-03 15:17:47,256 Parameters: cosmological_simulation = 1.0 yt : [INFO ] 2016-11-03 15:17:47,256 Parameters: current_redshift = -1.48991929905e-13 yt : [INFO ] 2016-11-03 15:17:47,256 Parameters: omega_lambda = 0.728 yt : [INFO ] 2016-11-03 15:17:47,256 Parameters: omega_matter = 0.272 yt : [INFO ] 2016-11-03 15:17:47,256 Parameters: hubble_constant = 1.89812815754e-06
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participants (3)
-
B.W. Keller -
Christine Simpson -
Nathan Goldbaum