Copyright | (c) 2019 Tobias Reinhart and Nils Alex |
---|---|
License | MIT |
Maintainer | tobi.reinhart@fau.de, nils.alex@fau.de |
Safe Haskell | None |
Language | Haskell2010 |
This module provides the Schwarzschild metric as an example for a tensor with symbolic values as well as functions to calculate Christoffel symbols, Ricci tensors and Einstein tensors from metric tensors with symbolic values.
Synopsis
- schwarzschildS :: STTens 0 2 SSymbolic
- schwarzschildS' :: STTens 2 0 SSymbolic
- christoffelS :: STTens 0 2 SSymbolic -> STTens 2 0 SSymbolic -> STTens 1 2 SSymbolic
- ricciS :: STTens 0 2 SSymbolic -> STTens 2 0 SSymbolic -> STTens 0 2 SSymbolic
- einsteinS :: STTens 0 2 SSymbolic -> STTens 2 0 SSymbolic -> STTens 0 2 SSymbolic
Documentation
schwarzschildS :: STTens 0 2 SSymbolic Source #
Schwarzschild metric \( g = (1-\frac{r_\text{s}}{r})\,\mathrm dt\otimes\mathrm dt - \frac{1}{1-\frac{r_\text{s}}{r}}\,\mathrm dr\otimes \mathrm dr - r^2\,\mathrm d\theta\otimes \mathrm d\theta - r^2\sin^2\theta\,\mathrm d\phi\otimes \mathrm d\phi \).
schwarzschildS' :: STTens 2 0 SSymbolic Source #
Inverse Schwarzschild metric \( g = \frac{1}{1-\frac{r_\text{s}}{r}}\,\partial_t \otimes \partial_t - (1-\frac{r_\text{s}}{r})\,\partial_r \otimes \partial_r - \frac{1}{r^2}\,\partial_\theta \otimes \partial_\theta - \frac{1}{r^2\sin^2\theta}\,\partial_\phi \otimes \partial_\phi \).
christoffelS :: STTens 0 2 SSymbolic -> STTens 2 0 SSymbolic -> STTens 1 2 SSymbolic Source #
Christoffel symbols of any symbolic metric.
ricciS :: STTens 0 2 SSymbolic -> STTens 2 0 SSymbolic -> STTens 0 2 SSymbolic Source #
Ricci tensor of any symbolic metric.
einsteinS :: STTens 0 2 SSymbolic -> STTens 2 0 SSymbolic -> STTens 0 2 SSymbolic Source #
Einstein tensor of any symbolic metric. The components evaluate to zero:
>>>
let g = schwarzschildS
>>>
let g' = schwarzschildS'
>>>
let e = einsteinS g g'
>>>
print e
ZeroTensor -- modulo symbolic simplification, which is not implemented yet.