3+1 Variables

The variables provided by ADMBase are:

• The 3-metric tensor, $g_{ij}$

  gxx, gxy, gxz,gyy, gyz,gzz

• The extrinsic curvature tensor, $K_{ij}$

  kxx, kxy, kxz,kyy,kyz,kzz

• The lapse function, $\alpha$

  alp

• The (optional) shift vector $\beta^i$

  betax, betay,betaz

By default the metric and extrinsic curvature tensors are assumed to be physical, however these semantics can be changed by use of the metric_type parameter. ADMBase provides the default value of physical, however another thorn can extend this parameter, for example to specify that the variables gxx etc actually refer to the conformal 3-metric.