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SpECTRE
v2026.06.09.01
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Computes and returns spacetime quantities of interest. More...
#include <HarmonicSchwarzschild.hpp>
Computes and returns spacetime quantities of interest.
| tnsr::i< DataType, 3, Frame > gr::Solutions::HarmonicSchwarzschild::IntermediateVars< DataType, Frame >::get_var | ( | const IntermediateComputer< DataType, Frame > & | computer, |
| DerivLapse< DataType, Frame > | ) |
Computes and returns the spatial derivative of the lapse.
Computed as
\begin{align} \partial_i \alpha &= -\frac{1}{2} \gamma_{rr}^{-3/2} \partial_r \gamma_{rr} \frac{X_i}{r} \end{align}
where \(r\) is the radius defined by internal_tags::r, \(\gamma_{rr}\) is defined by internal_tags::spatial_metric_rr, its derivative \(\partial_r \gamma_{rr}\) is defined by internal_tags::d_spatial_metric_rr, and \(X_j = X^i \delta_{ij}\) where \(X^i\) is defined by internal_tags::x_minus_center.