[yt-dev] Projection wipes grids

[Elizabeth Tasker]

Hi,

I'm using a code which creates a new field by assigning values to
individual cells.

If --in the middle of the script-- I create a projected image, the new
field gets wiped.

This script demonstrates the problem:

http://paste.yt-project.org/show/2517/

Here, the code loops over two objects, and gives their neighbouring
cells values in the new field and creates an extracted region from
those cells.

When the second object is called, the code reassigns its cells to
object one and creates a new extracted region of object one's cells.

If line 53 is not called (p = pc.add_projection("Density", 2)), this
is fine. Both objects initially have 26 cells and then object one gets
52 cells.

If the projection is created, the code forgets about the cells it
assigned to object 1 in the first loop and object 1 ends up with only
object 2's cells.


This isn't a huge problem for me, since I can just ensure I never call
a projection during my script.

But.... I am liable to forget and clobber my data at a later point! Is
it easy to somehow bank the new field so it's not destroyed during a
projection? (If not, no worries.)

(Matt, I know we previously discussed how projection didn't know about
the new field. Possibly, this is a logical consequence from that and
if so, I'm sorry to repeat the question!)

Elizabeth