Add new grid functions for dtlapse and dtbetax, dtbetay, and dtbetaz.

Also add several state variables so that codes can determine whether
these variables have storage; storage is off by default for backwards
compatibility.  This is similar to the way in which the shift vector
is handled, which also has no storage by default.

This is necessary since the ADMBase variables store currently the
3-metric, lapse, shift, and extrinsic curvature.  They do not store
the time derivatives of lapse and shift, which makes it impossible to
calculate the time derivative of the 4-metric from the ADMBase
variables.  This is a shortcoming, since almost all current evolution
systems require these, including common BSSN gauge conditions and
harmonic evolution schemes.  (In many cases, initial data assume that
these additional time derivatives are zero to get around this issue.)


git-svn-id: http://svn.einsteintoolkit.org/cactus/EinsteinBase/ADMBase/trunk@40 d576a68a-b34a-40ae-82fc-004fa1a9d16f

0 files changed, 0 insertions, 0 deletions