Thank you for your response. I haven't actually tried the example, as my expression is much more complex. However, let's say I want to take the covariant derivative of the following vector with respect to the Schwarzschild metric: (1-M/r)dt^2. How would one construct that to take a covariant derivative?
On Monday, May 30, 2016 at 4:38:48 PM UTC-4, Eric Gourgoulhon wrote: > > Hi, > > Le lundi 30 mai 2016 17:31:14 UTC+2, Zach Elgood a écrit : >> >> Hello again, >> Thank you very much for the previous help. Some of the research I do >> involves using actions to calculate things like the Euler Lagrange >> equations. I was wondering if this is possible to do in Sage. >> > > To my knowledge, no variational calculus is implemented in Sage yet. But > this would be a nice project! > > >> For example, if I had the Lagrangian >> >> Nabla_mu(phi) Nabla^mu (phi)-m^2*phi^2 >> >> how would I go about constructing one? I tried simply defining it, but I >> keep getting the attribute 'sage.symbolic.expression.Expression' object >> has no attribute '_domain' when I try and take the covariant derivative >> of it. >> > > A reason could be that phi has not been defined as a scalar field (i.e. as > phi = M.scalar_field(...)), but merely as a symbolic expression. Is it the > case? > > Best wishes, > > Eric. > -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
