[yt-users] Clearing a derived field from all grids

[Elizabeth Tasker]

Problem solved! Thank you!!

Elizabeth

On 13 December 2011 21:03, Matthew Turk <matthewturk at gmail.com> wrote:
> Hi Elizabeth,
>
> On Tue, Dec 13, 2011 at 4:14 AM, Elizabeth Tasker
> <tasker at astro1.sci.hokudai.ac.jp> wrote:
>> Hi Matt,
>>
>> Sorry, this is still a problem for my set-up.
>>
>> The issue is that EffectivePotential is only created on some grids,
>> not all of them, so if I do:
>>
>> for g in pf.h.grids: del g[field_name]
>>
>> it freaks out when it can't find the field.
>>
>> But, I don't want to delete the grids as I go, because then I end up
>> calculating EffectivePotential a ridiculous number of times.
>>
>> Yet, if I don't clear it as we go through that c loop, my results get
>> screwed up.
>>
>> So what I need is:
>>
>> for c in (nclouds):
>>
>>    grids, cis = kd.locate_neighbors_from_position(position)
>>     for  n in range(26):
>>           phi = grids[n]["EffectivePotential"][cis[n]]
>>
>>    << clear all the grids that have EffectivePotential on them before
>> c increments and it needs to be recalculated>>
>>
>>
>> Is it possible to hack yt so that
>>
>> for g in pf.h.grids: del g[field_name]
>>
>> just chills out and moves on if it can't find the field_name? Or do a
>> (if this field exists, delete grid) line?
>>
>
> No hacking needed.  Grids have a "has_key" function.
>
> for g in pf.h.grids:
>    if g.has_key(field_name): del g[field_name]
>
> -Matt
>
>>
>> Elizabeth
>>
>>
>>
>> On 13 December 2011 12:14, Matthew Turk <matthewturk at gmail.com> wrote:
>>> Hi Elizabeth,
>>>
>>> Yes, sorry, I misread 'ng'.  I'll be more explicit -- if you have a
>>> GridPatch object, you can do "del grid[field_name]" and it will remove
>>> it.  One thing you can do is iterate over the grids, as you note, like
>>> this:
>>>
>>> for g in pf.h.grids: del g[field_name]
>>>
>>> Good luck.
>>>
>>> -Matt
>>>
>>> On Mon, Dec 12, 2011 at 8:58 PM, Elizabeth Tasker
>>> <tasker at astro1.sci.hokudai.ac.jp> wrote:
>>>> Hi Matt,
>>>>
>>>> Unfortunately, that doesn't work.
>>>>
>>>> I can do:
>>>>
>>>> del ng[n][fieldname]
>>>>
>>>> But then I'd have to recreate the field afresh for each grid (very
>>>> slow), as opposed to just when I rerun the whole loop again:
>>>>
>>>> for c in (nclouds):
>>>>  grids, cis = kd.locate_neighbors_from_position(position)
>>>>  for  n in range(26):
>>>>    phi = grids[n]["EffectivePotential"][cis[n]]
>>>>     del grids[n]["EffectivePotential"]
>>>>
>>>> I really want to delete every c-loop, not every n loop.
>>>>
>>>> Possibly the best way is to loop over the n loop again and delete the
>>>> grids afterwards:
>>>>
>>>> for n in range(26):
>>>> del grids[n]["EffectivePotential"]
>>>>
>>>> Which is fine, I was just checking if there was a neater way!
>>>>
>>>> Elizabeth
>>>>
>>>>
>>>> On 12 December 2011 20:18, Matthew Turk <matthewturk at gmail.com> wrote:
>>>>> Hi Elizabeth,
>>>>>
>>>>> You can do:
>>>>>
>>>>> del ng[fieldname]
>>>>>
>>>>> -Matt
>>>>>
>>>>> On Dec 12, 2011 5:45 AM, "Elizabeth Tasker"
>>>>> <tasker at astro1.sci.hokudai.ac.jp> wrote:
>>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> Is there a way of deleting a single derived field from all grids?
>>>>>>
>>>>>> I seem to be having a problem with my derived field not being
>>>>>> re-calculated for every element in a loop (it needs to be). Therefore,
>>>>>> if I run the complete loop, I get an incorrect result for some of the
>>>>>> elements which are totally fine if I tell the code to just calculate
>>>>>> that element in a single sweep.
>>>>>>
>>>>>> I've tried deleting the individual elements that use that variable,
>>>>>> but it doesn't seem to be enough, e.g.
>>>>>>
>>>>>> ng, nc = kd.locate_neighbors_from_position(nposn)
>>>>>> .
>>>>>> .
>>>>>> .
>>>>>> del ng
>>>>>>
>>>>>>
>>>>>> Elizabeth
>>>>>> _______________________________________________
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>>>>>> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
>>>>>
>>>>>
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