[yt-users] yt-3.0 : derived fields in python notebooks

[Elizabeth Tasker]

Hooray! Thank you.

On 14 November 2014 23:14, Britton Smith <brittonsmith at gmail.com> wrote:

> Hi Elizabeth,
>
> I don't know whether that syntax works anymore, but the following should:
> have your field function without the @derived_field decorator, and then,
> after ds = yt.load(...), do ds.add_field("thermalenergy", function=...,
> units=...)
>
> Britton
>
>
> On Fri, Nov 14, 2014 at 11:33 AM, Elizabeth Tasker <
> tasker at astro1.sci.hokudai.ac.jp> wrote:
>
>> Hi,
>>
>> I'm hitting a problem with deriving a field within a python notebook with
>> yt 3.0. I'm following:
>>
>>
>> http://yt-project.org/docs/3.0/quickstart/derived_fields_and_profiles.html
>>
>> and have:
>>
>> @derived_field(name = "thermenergy", units = "g * cm**2/s**2")
>> def _thermenergy(field, data):
>>     return data[("gas", "cell_mass")]*data[("gas", "thermal_energy")]
>>
>>
>> but I get:
>>
>> TypeError                                 Traceback (most recent call
>> last)
>> <ipython-input-30-55b30d60c209> in <module>()
>> ----> 1 @derived_field(name = "thermenergy", units = "g * cm**2/s**2")
>>       2 def _thermenergy(field, data):
>>       3     return data[("gas", "cell_mass")]*data[("gas",
>> "thermal_energy")]
>>       4
>>       5 yt.add_field("thermenergy", function=_thermenergy,
>> units="gcm**2/s**2")
>>
>> TypeError: 'NoneType' object is not callable
>>
>>
>> I don't get an error if I do:
>>
>> def _thermenergy(field, data):
>>     return data[("gas", "cell_mass")]*data[("gas", "thermal_energy")]
>>
>> yt.add_field("thermenergy", function=_thermenergy, units="gcm**2/s**2")
>>
>> but nor can I use the field:
>>
>> ds = yt.load("DD0002/sbcool_0002")
>> dd = ds.all_data()
>> dd["thermenergy"]
>>
>>
>> YTFieldNotFound                           Traceback (most recent call
>> last)
>> <ipython-input-33-c293394ac99f> in <module>()
>>       1 ds = yt.load("DD0002/sbcool_0002")
>>       2 dd = ds.all_data()
>> ----> 3 dd["thermenergy"]
>>
>>
>> ... what did I do wrong?
>>
>> Elizabeth
>>
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>>
>
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