Hi Matt, I think this script explains what I mean. When I run it, I get: /1/home/taskere/yt/yt/data_objects/field_info_container.py in __call__(self, data) 357 doesnt_have.append(p) 358 if len(doesnt_have) > 0: --> 359 raise NeedsParameter(doesnt_have) 360 return True 361 NeedsParameter: (['height_vector']) As a side note, I think 'ray' sets its own value for the field parameter, "center", making it the start of the ray. If that's true, does it have problems for calling radius? e.g. ray["Radius"] where radius would need to be the center of the object, not necessarily the start of the ray? (This particular issue wouldn't affect me, but I thought it might bite someone later). Elizabeth Matthew Turk wrote:

Hi Elizabeth,

Could you elaborate on what you mean, and provide an example script?

Thanks,

-Matt

On Aug 10, 2011 7:22 AM, "Elizabeth Tasker" <taskere@mcmaster.ca <mailto:taskere@mcmaster.ca>> wrote:

...

Hi,

I'm having problems passing parameters to a ray object. I'm trying:

ray1 = pf.h.ray( com[c], com[nearestcore], field_parameters = {'height_vector':na.array([0,0,1]), 'center':dd.center}) Omega0 = ray1["Omega"]

and I also tried out:

ray1.set_field_parameter("height_vector", na.array([0,0,1])) ray1.set_field_parameter("center", dd.center)

But it can't recognise them.

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Hi Sam, Thank you -- my test script now works fine but I've managed to break my longer one so completely it's become impossible to test anything. Oops. However, I think when I tried the method below originally, I put the set_field_parameters in the wrong place, which would explain why they didn't work. Thanks loads for the example. Elizabeth Sam Skillman wrote:

Hi Elizabeth,

So the problem is that when you add_field and ask to validate the height_vector, it doesn't exist yet. I believe you can get the desired behavior with:

from yt.mods import *

def _RayTest(field, data):

center = data.get_field_parameter("center") h_vec = na.array(data.get_field_parameter("height_vector"))

print "center :", center, "h_vec: ", h_vec

return data["Density"]

add_field("RayTest", function=_RayTest)

# Grab data fn = "GravPotential/DD0301/GT_BTAccel_256AMR4_PeHeat_sf5_SNe_0301" pf = load(fn) ray1 = pf.h.ray((2.0, 2.0 ,2.0), (12.0, 12.0, 12.0)) ray1.set_field_parameter('height_vector',na.array([0.,0.,1.])) ray1.set_field_parameter('center',[0.5]*3) ray1["RayTest"]

When I run this I get: center : [0.5, 0.5, 0.5] h_vec: [ 0. 0. 1.]

I'm not sure what dd was in your dd.center since dd wasn't defined in that script, but you should be able to set center to whatever you want here. I also changed density to Density.

Best, Sam

On Wed, Aug 10, 2011 at 9:36 AM, Elizabeth Tasker <taskere@mcmaster.ca <mailto:taskere@mcmaster.ca>> wrote:

Hi Matt,

I think this script explains what I mean. When I run it, I get:

/1/home/taskere/yt/yt/data_objects/field_info_container.py in __call__(self, data) 357 doesnt_have.append(p) 358 if len(doesnt_have) > 0: --> 359 raise NeedsParameter(doesnt_have) 360 return True 361

NeedsParameter: (['height_vector'])

As a side note, I think 'ray' sets its own value for the field parameter, "center", making it the start of the ray. If that's true, does it have problems for calling radius? e.g.

ray["Radius"]

where radius would need to be the center of the object, not necessarily the start of the ray? (This particular issue wouldn't affect me, but I thought it might bite someone later).

Elizabeth

Matthew Turk wrote:

Hi Elizabeth,

Could you elaborate on what you mean, and provide an example script?

Thanks,

-Matt

On Aug 10, 2011 7:22 AM, "Elizabeth Tasker" <taskere@mcmaster.ca <mailto:taskere@mcmaster.ca> <mailto:taskere@mcmaster.ca <mailto:taskere@mcmaster.ca>>> wrote: > Hi, > > I'm having problems passing parameters to a ray object. I'm trying: > > ray1 = pf.h.ray( com[c], com[nearestcore], field_parameters = > {'height_vector':na.array([0,0,1]), 'center':dd.center}) > Omega0 = ray1["Omega"] > > and I also tried out: > > ray1.set_field_parameter("height_vector", na.array([0,0,1])) > ray1.set_field_parameter("center", dd.center) > > But it can't recognise them. > > Elizabeth > _______________________________________________ > yt-users mailing list > yt-users@lists.spacepope.org <mailto:yt-users@lists.spacepope.org> <mailto:yt-users@lists.spacepope.org <mailto:yt-users@lists.spacepope.org>>

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