Ask Your Question
0

Problem with Metric Tensor coordinate change.

asked 2021-07-04 22:32:34 +0100

AlanTStafford gravatar image

I define a M manifold with three charts, I then define a metric on one of the charts MH. I then want to see the metric components in one of the other charts BL. I have defined differential maps between the charts.

gMann(MH) works and I can display the components but,

gMann(BL) gives the error:

ValueError: the provided domain is not a subset of the field's domain

print(subdomain,self._restrictions) gives 'Open subset MBL of the 4-dimensional Lorentzian manifold M {}' .

How do I make this work please? I will post the code in comments below.

edit retag flag offensive close merge delete

Comments

Link to code at my website. The problem surfaces in cell 6. The function definitions between cell two and six can be ignored.

http://alan.atstafford.co.uk/BlackHol...

AlanTStafford gravatar imageAlanTStafford ( 2021-07-04 22:38:50 +0100 )edit

1 Answer

Sort by ยป oldest newest most voted
1

answered 2021-07-05 17:07:44 +0100

eric_g gravatar image

You should define the transition maps via the method transition map of charts and not as a differentiable map, i.e. replace

to_MH_from_BL = M.diff_map(MMH, {(BL, MH): ...})

by

to_MH_from_BL = BL.transition_map(MH, ...)

and then use

show(gMann.display(BL.restrict(MMH.intersection(MBL))))

instead of show(gMann.display(BL) since gMann is not defined on BL's domain, as said in the error message.

edit flag offensive delete link more

Comments

Thank you, answer accepted. I was nearly there trying restrict but hadn't got to using an intersection. I have the maps the wrong way round in the code. The ones I am using are.

`

to_MH_from_BL = BL.transition_map(MH,  [       t, 
                                               r, 
                                               cos(th), 
                                               phi
                                           ])

to_BL_from_MH = MH.transition_map(BL,      [   t,
                                               x,
                                               arccos(y),
                                               phi
                                           ])

`

AlanTStafford gravatar imageAlanTStafford ( 2021-07-05 17:41:35 +0100 )edit

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

Question Tools

1 follower

Stats

Asked: 2021-07-04 22:32:34 +0100

Seen: 289 times

Last updated: Jul 05 '21