Hi Yuan,

I do something like this:

def _velocity_los(field, data):
    vel_axis = data.get_field_parameter("axis")
    if iterable(vel_axis):
        ret = data[ftype, "velocity_x"]*vel_axis[0] + \
              data[ftype, "velocity_y"]*vel_axis[1] + \
              data[ftype, "velocity_z"]*vel_axis[2]
    elif vel_axis > 2:
        raise NeedsParameter(["axis"])
    else:
        ret = data[ftype, "velocity_%s" % ({0: "x", 1: "y", 2: "z"}[vel_axis])]
    return ret

ds.add_field(("gas", "velocity_los"), function=_velocity_los, units="cm/s”)

and then you set a field parameter, e.g.:

sp = ds.sphere(“c”, (1.0, “Mpc”)
sp.set_field_parameter(“axis”, np.array([0.1, -0.2, 0.3]))

On Jul 1, 2019, at 4:46 PM, Yuan Li <yuan.astro@gmail.com> wrote:

Thank you, Suoqing and Nathan!

While I am on it... is there a good way of getting weighted average off-axis velocity? I guess I can do x, y and z separately and then add them up, but that feels silly.

Yuan

On Mon, Jul 1, 2019 at 1:43 PM Nathan Goldbaum <nathan12343@gmail.com> wrote:
Yes, that is the image you want in the end.

No need to report the issue, I guess we're overdue for a new yt release :)

On Mon, Jul 1, 2019 at 4:35 PM Ji, Suoqing <suoqing@caltech.edu> wrote:
This bug has already been fixed in the dev version by Bili: https://github.com/yt-project/yt/pull/2239

Best wishes,
—
Suoqing Ji
Sherman Fairchild Fellow
TAPIR & Walter Burke Institute for Theoretical Physics
California Institute of Technology
http://www.tapir.caltech.edu/~suoqing

On Jul 1, 2019, at 1:17 PM, Yuan Li <yuan.astro@gmail.com> wrote:

Hi Nathan,

Thank you! I am using the latest version of yt.

Just want to confirm -- if I use off_axis_projection, e.g. if I have 
>>> image=yt.off_axis_projection(data_source=ds........)
then is image basically the frb that I wanted to get from OffAxisProjectionPlot? 

Thanks!
Yuan

On Mon, Jul 1, 2019 at 1:10 PM Nathan <nathan.goldbaum@gmail.com> wrote:
Hi Yuan,

What yt version are you using? If it's something older than yt 3.5.1 can you try updating? If it is yt 3.5.1 then this is a bug and should be fixed. Please report it as such on GitHub so it doesn't get lost.

A workaround would be to use the off_axis_projection interface directly:


On Mon, Jul 1, 2019 at 3:57 PM Yuan Li <yuan.astro@gmail.com> wrote:
Hello,

I am trying to get an array out of an off axis projection with a chosen resolution.
This is what I have:
plot = yt.OffAxisProjectionPlot(ds, [1, 1, 1], 'density')
plot.set_buff_size(1600)
image = plot.frb[“gas”, “density”]

According to Nathan's email to Stephanie last year,
"image will be a 1600x1600 2D ndarray containing an image of the density field."

However, it is not working for me. image is still 800x800.
I do see this message:
yt : [INFO     ] 2019-07-01 15:51:04,868 Making a fixed resolution buffer of (('gas', 'density')) 1600 by 1600
so it seems that yt is making a FRB with the desired resolution, but how do I get the array?

Thanks!
Yuan
_______________________________________________
yt-users mailing list -- yt-users@python.org
To unsubscribe send an email to yt-users-leave@python.org
_______________________________________________
yt-users mailing list -- yt-users@python.org
To unsubscribe send an email to yt-users-leave@python.org
_______________________________________________
yt-users mailing list -- yt-users@python.org
To unsubscribe send an email to yt-users-leave@python.org

_______________________________________________
yt-users mailing list -- yt-users@python.org
To unsubscribe send an email to yt-users-leave@python.org
_______________________________________________
yt-users mailing list -- yt-users@python.org
To unsubscribe send an email to yt-users-leave@python.org
_______________________________________________
yt-users mailing list -- yt-users@python.org
To unsubscribe send an email to yt-users-leave@python.org