drwbia's profile - activity

B = function('B')(X,rh)

d_Ph_X = function('d_Ph_X')(X,rh,ph)

d_Ph_rh = function('d_Ph_rh')(X,rh,ph)

d_Ph_ph = function('d_Ph_ph')(X,rh,ph)

P = function('P')(t)

g = M.metric()

g[0,0] = (-1+B2* ((P+d_Ph_X/B2)2 +(d_Ph_rh/B2)2 +((1/rhd_Ph_ph/B2)*2 ))).simplify_full()

g[1,1] = (B**2).simplify_full()

g[2,2] = (B**2).simplify_full()

g[3,3] = (rh2*B2).simplify_full()

g[0,1] = (B2*(P+d_Ph_X/B2)).simplify_full()

g[0,2] = (B2*( d_Ph_rh/B2)).simplify_full

g[0,2] = (B2*( d_Ph_rh/B2)).simplify_full()

g[0,3] = (B2*( d_Ph_ph/B2)).simplify_full()

g.display()

g.christoffel_symbols_display()

@eric_g --> I installed it via conda

conda install mamba -c conda-forge # installs mamba

mamba create -n sage sage -c conda-forge # replaces "conda create..."

indeed you're right about the converting process that i should follow, thx I just found out that doing what you said indeed enabled the computation on my computer. without any modification of the memory available for sage. However a rather small modification of this metric does not work even with simplify_full, whereas it does with sage 8.9 (yielding "unreasonably" long expressions ^^)

thx a lot for your time/insight! actually it did not work on my computer with sage 9.1 and it did work on the 1st attempt with sage 8.9, something really is different with 9.1 i guess... by the way using sage 8.9 also enabled me to retrieve all my .sws which were completely impossible to load on sage 9.1... life is strange sometimes ;) --> i now am a happy sage 8.9 user

In a Sage 9.1 Jupyter notebook I tried the following SageManifolds commands

M = Manifold(4, 'M', structure='Lorentzian')

Mani.<t,X,rh,ph> = M.chart(r"t X:(-oo,+oo) rh:(0,+oo):\rho ph:(0,2*pi):\phi")

B = function('B')(X,rh,ph)
d_Ph_X = function('d_Ph_X')(X,rh,ph)
d_Ph_rh = function('d_Ph_rh')(X,rh,ph)
d_Ph_ph = function('d_Ph_ph')(X,rh,ph)

g = M.metric()

g[0,0] = (-1+B**2*  ((d_Ph_X/B**2)**2 +(d_Ph_rh/B**2)**2 +((1/rh*d_Ph_ph/B**2)**2     )))

g[1,1] = B**2
g[2,2] = B**2
g[3,3] = rh**2*B**2

g[0,1] = B**2*(d_Ph_X/B**2)
g[0,2] = B**2*( d_Ph_rh/B**2)
g[0,3] = B**2*( d_Ph_ph/B**2)

g.christoffel_symbols_display()

The last line makes the notebook overflow... i really don't understand why.

the computation, even if it is rather tedious, seems straightforward to me...

Any idea? Any help would be greatly appreciated.