Hi Sam,

your transpose fix DOES change things and it indeed may working now. 
Here is the first images I got for comparison.
I am going to make a few more pictures to see if things are all good.
Thanks very much,

On Jan 8, 2013, at 11:25 AM, Sam Skillman wrote:

Hi Renyue,

I have actually seen this on one other system but I could never reproduce it. Could you tell me the version of yt you are using? If you run "yt instinfo" it should tell you. I haven't seen this bug for the last few months so I thought it was gone.  

Additionally, can you try the following at the end of your script:


write_bitmap(im, 'test2.png', transpose=False)

I think there may have been something wrong with the transposing of the image for a short time period a few months ago.  I have very sporadic and unreliable internet at AAS but I'll try to respond as quickly as possible.

Sorry for the trouble,


On Jan 7, 2013 10:11 AM, "Renyue Cen" <cen@astro.princeton.edu> wrote:

I did some simple volume rendering with the following script:

    volume2 = AMRKDTree(pf, fields=["Dark_Matter_Density"],
                no_ghost=False, tree_type="domain",
                le=c-0.5*WW, re=c+0.5*WW)
    cam = pf.h.camera(c, L, W, N, tf, volume=volume2, no_ghost=False,
                north_vector=L, steady_north=True)
    cam.snapshot(fn="%s_iso-DMdensity-%3.3d.png" % (filenameTHIS, j))

I got rather strange results in that the pictures look symmetric, which I am pretty
sure can not be true.
I attach the obtained plot.
Note that I am using KD tree and using 32 cores. 

Your help at your earliest convenience is appreciated.