[yt-users] log scale issues when zero.....

[Matthew Turk]

Hi Libby,

I guess I don't really know what kind of behavior you'd like?  If yous
et the zlim manually, it should still work; what should it be set to,
on a log scale, if everything is zero?

-Matt

On Mon, Feb 28, 2011 at 11:02 AM, Elizabeth Harper-Clark
<h-clark at astro.utoronto.ca> wrote:
> Hi guys,
>
> one more thing. I want to calculate the radiation pressure force, and when
> there is some then plot it with a log scale. However if I set:
>
> def _ConvertAccel(data):
>     return data.convert("Length") / (data.convert("Time"))**2.0
> def _RadiationAccelerationMagnitude(field, data):
>     return ( (data["RadAccel1"])**2.0 + \
>              (data["RadAccel2"])**2.0 + \
>              (data["RadAccel3"])**2.0 )**(1.0/2.0)
> add_field("RadiationAccelerationMagnitude",
> function=_RadiationAccelerationMagnitude,
> take_log=True,convert_function=_ConvertAccel, units=r"\rm{cm}/\rm{s}^{2}")
> def _RadiationForceMagnitude(field, data):
>     return ( data["RadiationAccelerationMagnitude"] * data["Density"] *
> data["CellVolume"])
> add_field("RadiationForceMagnitude", function=_RadiationForceMagnitude,
> take_log=True, units=r"\rm{dynes}")
>
>
> before the stars switch on when the radiation acceleration baryon fields are
> all 0.0 everywhere I get the following error:
>
>
> Traceback (most recent call last):
>   File "MultiPlotProj.py", line 65, in <module>
>     s = pc.add_projection("RadiationForceMagnitude", ax,
> weight_field="Density", figure=fig, axes=axes[0][3], use_colorbar=False)
>   File "/home/h-clark/YT/src/yt-hg/yt/visualization/plot_collection.py",
> line 742, in add_projection
>     size=fig_size, periodic=periodic))
>   File "/home/h-clark/YT/src/yt-hg/yt/visualization/plot_types.py", line
> 310, in __init__
>     self.__init_temp_image(use_colorbar)
>   File "/home/h-clark/YT/src/yt-hg/yt/visualization/plot_types.py", line
> 347, in __init_temp_image
>     self.set_width(1,'unitary')
>   File "/home/h-clark/YT/src/yt-hg/yt/visualization/plot_types.py", line
> 436, in set_width
>     self._refresh_display_width()
>   File "/home/h-clark/YT/src/yt-hg/yt/visualization/plot_types.py", line
> 454, in _refresh_display_width
>     self._redraw_image()
>   File "/home/h-clark/YT/src/yt-hg/yt/visualization/plot_types.py", line
> 384, in _redraw_image
>     newmin = na.nanmin(buff[bI])
>   File
> "/home/h-clark/YT/lib/python2.6/site-packages/numpy/lib/function_base.py",
> line 1494, in nanmin
>     return _nanop(np.min, np.inf, a, axis)
>   File
> "/home/h-clark/YT/lib/python2.6/site-packages/numpy/lib/function_base.py",
> line 1355, in _nanop
>     res = op(y, axis=axis)
>   File
> "/home/h-clark/YT/lib/python2.6/site-packages/numpy/core/fromnumeric.py",
> line 1829, in amin
>     return amin(axis, out)
> ValueError: zero-size array to ufunc.reduce without identity
>
>
> Is there a way to set it so I get a log scale when plotting projections that
> does not break when the fields are all zero?
>
> Many thanks,
>
> Libby
>
>
>
> --
> Elizabeth Harper-Clark MA MSci
> PhD Candidate, Canadian Institute for Theoretical Astrophysics, UofT
> Sciences and Engineering Coordinator, Teaching Assistants' Training Program,
> UofT
>
> www.astro.utoronto.ca/~h-clark
> h-clark at cita.utoronto.ca
> Astronomy office phone: +1-416-978-5759
>
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