diff options
| author | cott <cott@otto.(none)> | 2008-10-08 08:38:09 -0700 |
|---|---|---|
| committer | cott <cott@otto.(none)> | 2008-10-08 08:38:09 -0700 |
| commit | c73e059d6c07eabf7b728b8588f50d98c6371338 (patch) | |
| tree | 9f82cda5f58678ae5e7104e2f046c93c645f5f61 /Carpet/CarpetLib/src/prolongate_3d_real8_eno.F90 | |
| parent | f091cf09cc7b6dbc8284915a6b093a0a9f82e646 (diff) | |
* add additional check to eno1d: We want to interpolate
quadratically only if the sign of the curvature of the
interpolating polynomial does not change.
* add a few more comments / explanations.
Diffstat (limited to 'Carpet/CarpetLib/src/prolongate_3d_real8_eno.F90')
| -rw-r--r-- | Carpet/CarpetLib/src/prolongate_3d_real8_eno.F90 | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/Carpet/CarpetLib/src/prolongate_3d_real8_eno.F90 b/Carpet/CarpetLib/src/prolongate_3d_real8_eno.F90 index b29b21580..4b5be092e 100644 --- a/Carpet/CarpetLib/src/prolongate_3d_real8_eno.F90 +++ b/Carpet/CarpetLib/src/prolongate_3d_real8_eno.F90 @@ -40,6 +40,8 @@ function eno1d(q) CCTK_REAL8 :: diffleft, diffright !!$ Directly find the second undivided differences +!!$ We need to pick between discrete values at +!!$ 1 2 3 4 for the interpolation between 2 and 3. diffleft = q(1) + q(3) - two * q(2) diffright = q(2) + q(4) - two * q(3) @@ -58,9 +60,15 @@ function eno1d(q) end if -!!$ Check that the quadratic is reasonable +!!$ Check that the quadratic is reasonable: +!!$ Check 1: interpolated value between +!!$ values at interpolation points +!!$ Check 2: sign of the curvature of the interpolating +!!$ polynomial does not change. - if ( (eno1d-q(2)) * (q(3)-eno1d) .lt. zero ) then + if ( ((eno1d-q(2)) * (q(3)-eno1d) .lt. zero) & + .or. & + (diffleft*diffright .le. zero) ) then !!$ Not reasonable. Linear interpolation |