# Tachyon in SageMathCloud

I'm new to Sage and only beginner experience in python, so there may be something obvious I'm missing.

I'm trying to create, initially, some plots using Tachyon in SMC. I cut and pasted Niles Johnson's code at this question, namely

sage: f = lambda t: (t,t^2,t^3)
sage: t = Tachyon(camera_center=(5,0,4))
sage: t.texture('t')
sage: t.light((-20,-20,40), 0.2, (1,1,1))
sage: t.parametric_plot(f,-5,5,'t',min_depth=6)
sage: t.show(verbose=True)


and I get the following error

tachyon /projects/6e9b9fc6-5d3c-4c2a-a57f-b5fe78a365fd/.sage/temp/compute2dc1/22136/tmp_Iy4Cih.dat  -format PNG  -o /projects/6e9b9fc6-5d3c-4c2a-a57f-b5fe78a365fd/.sage/temp/compute2dc1/22136/tmp_weeBQD.png   ; rm -f "/projects/6e9b9fc6-5d3c-4c2a-a57f-b5fe78a365fd/.sage/temp/compute2dc1/22136/tmp_Iy4Cih.dat"
Error in lines 6-6
Traceback (most recent call last):
File "/projects/6e9b9fc6-5d3c-4c2a-a57f-b5fe78a365fd/.sagemathcloud/sage_server.py", line 864, in execute
exec compile(block+'\n', '', 'single') in namespace, locals
File "", line 1, in <module>
File "/usr/local/sage/sage-6.3.beta6/local/lib/python2.7/site-packages/sage/plot/plot3d/tachyon.py", line 339, in show
os.system('%s %s 2>/dev/null 1>/dev/null &'%(sage.misc.viewer.png_viewer(), filename))
NameError: global name 'sage' is not defined


What should I do? It doesn't seem related to anything in the code used.

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It works on a classical (local) installation, so the pb might come from the cloud.

( 2014-11-03 10:17:17 +0200 )edit

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You're hitting a bug in sage-6.3 (the bug has nothing to do with SageMathCloud). It's evidently fixed in sage-6.4, but even then, I don't think that way of viewing a tachyon plot would work in SMC. In any case, here's how to do this in SMC, which works now:

f = lambda t: (t,t^2,t^3)
t = Tachyon(camera_center=(5,0,4))
t.texture('t')
t.light((-20,-20,40), 0.2, (1,1,1))
t.parametric_plot(f,-5,5,'t',min_depth=6)
t.save('a.png')
salvus.file('a.png')


Here's a worksheet illustrating make the 3d plot you want to make, using the regular interactive 3d viewer and also tachyon:

https://cloud.sagemath.com/projects/4...

more

I'd upvote, but I've not got the required karma. Virtual +1 from me, then.

( 2014-11-03 23:53:21 +0200 )edit