New issue 832: In Enzo data 'dynamical_time' field returns inconsistent results https://bitbucket.org/yt_analysis/yt/issue/832/in-enzo-data-dynamical_time-f...
For Enzo datasets, using the field name 'dynamical_time' instead of the full field ('all', 'dynamical_time'), ('io', 'dynamical_time'), or ('gas', dynamical_time') produces inconsistent results. As far as I can tell, this is because it is the only field that is defined with the same name for both particles and gas. Depending on which fields have been called previously, the field returned by 'dynamical_time' may be either one or the other. I haven't been able to figure out a clear pattern for when each is returned.
The attached example.py should help illustrate what I mean as long as you have an Enzo dataset to give it. When I run this, using 'density' vs 'Density' produces consistently different results, while the first use of 'cooling_time' is different than subsequent calls.