[yt-users] Ray casting in simple volume rendering

[Matthew Turk]

Hi Nick,

Okay, so to debug this, we're going to have to figure out some things
about the simulation.  Can you insert these lines, below the line that
starts with "new_field =" around line 444 of
/Users/earln/yt-i386/src/yt-trunk-svn/yt/lagos/BaseGridType.py:

print new_field.shape, self.ActiveDimensions, self.Level, cf.shape,
print cg.ActiveDimensions, cg.left_edge, self.LeftEdge

and then reply to me, off-list, with the responses?  Once we've
figured it out, I'll report back to the list with a final update.  My
guess is that there's something in the machinery that generates ghost
zones that is getting confused and ends up returning an array that is
of shape one less or one more than it should be in one of the
dimensions.

Thanks,

Matt


On Wed, Mar 31, 2010 at 10:48 AM, Nicholas M. Earl <earlnich at msu.edu> wrote:
> Hey Matt,
>
> Yeah, it's 3d data.
>
> Nick
>
> On Mar 31, 2010, at 12:58 PM, Matthew Turk wrote:
>
>> Hi Nick,
>>
>> Are you using 3D data?
>>
>> -Matt
>>
>> On Wed, Mar 31, 2010 at 9:55 AM, Nicholas Earl <earlnich at msu.edu> wrote:
>>>
>>> This all sounds exciting, and I'm definitely making headway in terms of
>>> progress on the screen, but I keep getting hung up at a ValueError: shape
>>> mismatch: objects cannot be broadcast to a single shape after this line:
>>>
>>>    vcd = grid.get_vertex_centered_data(field).astype('float64')
>>>  File "/Users/earln/yt-i386/src/yt-trunk-svn/yt/lagos/BaseGridType.py",
>>> line 445, in get_vertex_centered_data
>>>    na.add(new_field, cf[1: ,1: ,1: ], new_field)
>>>
>>> Not quite sure wherein this would lie. Any possible ideas?
>>>
>>> Thanks!
>>> Nick
>>>
>>> On Tue, Mar 30, 2010 at 2:20 PM, Matthew Turk <matthewturk at gmail.com>
>>> wrote:
>>>>
>>>> Hi Nicholas,
>>>>
>>>> Yup, the cookbook applies to 1.6, but we've changed things a bit in
>>>> the trunk so as to enable parallel volume rendering -- and to make
>>>> some things nicer.  For instance, you can now sample colormaps,
>>>> automatically add layers, etc etc.  We're also just about ready to
>>>> roll out multivariate volume rendering, including planck functions and
>>>> scattering.
>>>>
>>>> Anyway, I'm sorry that it's not working right now for you!  To use the
>>>> script, we just need to get rid of direct_ray_cast, which we can
>>>> replace with:
>>>>
>>>> vp = pf.h.volume_rendering(L, W, c, Nvec, tf)
>>>> vp.ray_cast()
>>>>
>>>> At this point, we can get the image as vp.image:
>>>>
>>>> to_plot = na.clip(vp.image, vp.image.min(), 0.8 * vp.image.max())
>>>> to_plot = (to_plot - to_plot.min()) / (to_plot.max() - to_plot.min())
>>>>
>>>> (we still have to normalize, unfortunately -- we're working on that
>>>> for the future.)
>>>>
>>>> And we now also provide a saving function:
>>>>
>>>> vr.plot_rgb(to_plot, "%s" % pf)
>>>>
>>>> I've uploaded a new version of the cookbook recipe here:
>>>>
>>>> http://paste.enzotools.org/show/404/
>>>>
>>>> which you can download with "yt_lodgeit.py --download=404".  One thing
>>>> you might consider is that sometimes it's easier to just
>>>> "add_layers(N)" on the transfer function, optionally supplying the
>>>> name of a colormap (defaults to gist_stern) so that yt will add onion
>>>> layers to your image at even intervals.  I've uploaded an example of
>>>> that here:
>>>>
>>>> http://paste.enzotools.org/show/405/
>>>>
>>>> Anyway, sorry for the trouble, but I hope that the annoyance is worth
>>>> the new advantages!
>>>>
>>>> -Matt
>>>>
>>>> On Tue, Mar 30, 2010 at 11:07 AM, Nicholas M. Earl <earlnich at msu.edu>
>>>> wrote:
>>>>>
>>>>> Hey again YT community,
>>>>>
>>>>> I was hoping to get some heading on using the simple volume rending
>>>>> script
>>>>> that is written up in the YT cookbook, but it seems that
>>>>> direct_ray_casting
>>>>> isn't a part of yt extensions anymore? Is there something to substitute
>>>>> this? I see that in the software sample script, there is a referencing
>>>>> of
>>>>> VolumeRendering, can I use this?
>>>>>
>>>>> Thanks for your time and effort!
>>>>> Nicholas Earl
>>>>> _______________________________________________
>>>>> yt-users mailing list
>>>>> yt-users at lists.spacepope.org
>>>>> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
>>>>>
>>>> _______________________________________________
>>>> yt-users mailing list
>>>> yt-users at lists.spacepope.org
>>>> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
>>>>
>>>
>>>
>>> _______________________________________________
>>> yt-users mailing list
>>> yt-users at lists.spacepope.org
>>> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
>>>
>>>
>> _______________________________________________
>> yt-users mailing list
>> yt-users at lists.spacepope.org
>> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
>>
>
> _______________________________________________
> yt-users mailing list
> yt-users at lists.spacepope.org
> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
>