SetBasisChange

[Sebastian Szybka]

Hi,

The minimal (non)working example:

Needs["xAct`xCoba`"]
DefManifold[M, 2, IndexRange[a, d]]
DefChart[S, M, {0, 1}, {t[], r[]}]
DefScalarFunction[f]
bc = {{f[r[]], 0}, {0, f[r[]]}}
DefBasis[T, TangentM, {0, 1}, BasisColor -> Blue]
BC = CTensor[bc, {-T, S}]

Now, the command:

SetBasisChange[BC]

gives an error

WeightOf::error: WeightOf is generically undefined on scalar functions.
Throw::nocatch: Uncaught Throw[Null] returned to top level.

which vanishes if I substitute f[r]

SetBasisChange[BC /. f -> Function[r, Exp[r]]]

The metric functions that I use in my calculations are very complicated and I don't want to substitute them at this step. How to achieve this?

Best wishes,

Sebastian

PS
I am using the most recent version of xAct: {2018,2,28}.

[Alfonso Jacinto García Parrado Gómez Lobo]

Hi Sebastian,

as a workaround, I would suggest adding the following to your code:

WeightOf@f[r[]] ^= 0;


Alfonso.

---

From: xa...@googlegroups.com [xa...@googlegroups.com] on behalf of Sebastian Szybka [sebastia...@gmail.com]
Sent: Friday, May 04, 2018 6:56 PM
To: xAct Tensor Computer Algebra
Subject: [xAct: 2204] SetBasisChange

--
You received this message because you are subscribed to the Google Groups "xAct Tensor Computer Algebra" group.
To unsubscribe from this group and stop receiving emails from it, send an email to xact+uns...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[Sebastian Szybka]

Thank you. It solves the problem.

S.