diff options
-rw-r--r-- | m/McLachlan_BSSN.m | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/m/McLachlan_BSSN.m b/m/McLachlan_BSSN.m index ae5ae80..e2adac1 100644 --- a/m/McLachlan_BSSN.m +++ b/m/McLachlan_BSSN.m @@ -864,6 +864,12 @@ enforceCalc = Shorthands -> {detgt, gtu[ua,ub], trAt}, Equations -> { + (* Enforcing the constraints needs to be a projection, because it + is applied in MoL_PostStep and may thus be applied multiple + times, not only during time evolution. Therefore detgt has to + be calculated correctly, without assuming that det gt_ij = 1, + which is not always the case (since we don't enforce it). On + the other hand, this may not be so important... *) detgt -> 1 (* detgtExpr *), gtu[ua,ub] -> 1/detgt detgtExpr MatrixInverse [gt[ua,ub]], |