Hi Yosef,
I believe the code was reorganised in carpet and this needed the algorithm to change in a way that meant numerical results would change. I can't check right now, but this should have been mentioned in the announcement of the new version of carpet as well as the ET release notes.
--
Ian Hinder
ian.hinder@aei.mpg.de
----- Original message -----
> While trying to understand why the results from a BBH run
> differed when using the 2011_05 and 2011_10 version of ET
> I noticed that the two versions gave different results on every
> other point of the buffer region (in a 2 level run) on the 2nd
> time level.
>
> I reran the test using McLachlan and I found a similar
> behavior, but for fewer points (here, only 3, rather
> than 8) and only the innermost points.
>
>
> diff -w -u ~/ET/Old/Cactus/test/mc/gxx.x.asc ~/ET/Develop/Cactus/test/mc
> | grep "^[+-]2"
> -2 0 0 0 0 26 8 8 0.1 1.8 0 0 5.86163790879802
> +2 0 0 0 0 26 8 8 0.1 1.8 0 0 5.86163790879801
> -2 0 1 0 0 26 8 8 0.1 1.8 0 0 5.86163790879802
> +2 0 1 0 0 26 8 8 0.1 1.8 0 0 5.86163790879801
> -2 0 1 0 0 59 8 8 0.1 5.1 0 0 2.06954055131151
> +2 0 1 0 0 59 8 8 0.1 5.1 0 0 2.06940807802512
> -2 0 1 0 0 61 8 8 0.1 5.3 0 0 2.01672019300839
> +2 0 1 0 0 61 8 8 0.1 5.3 0 0 2.01674238678588
> -2 0 1 0 0 63 8 8 0.1 5.5 0 0 1.96875965038995
> +2 0 1 0 0 63 8 8 0.1 5.5 0 0 1.96875664800624
>
>
>
> One of the major differences between these two versions of ET is the
> switch from the git to hg version of carpet.
>
> Here is the full parfile that I used.
>
> #==============================================================================
>
> ActiveThorns = "admanalysis admbase admcoupling admmacros coordgauge
> spacemask StaticConformal boundary time cartgrid3d ioutil iobasic
> nanchecker CoordBase aeilocalinterp Slab SphericalSurface LocalReduce
> MoL Carpet CarpetInterp CarpetIOASCII CarpetLib CarpetReduce CarpetSlab
> CarpetRegrid2 SphericalSurface CarpetIOHDF5 CarpetIOScalar InitBase
> SymBase LoopControl GSL ReflectionSymmetry"
>
>
> ActiveThorns = "TimerReport"
>
> TimerReport::out_every = 512
> TimerReport::out_filename = "TimerReport"
> Carpet::output_timers_every = 512
> #------------------------------------------------------------------------------
>
> # Run parameters
> #------------------------------------------------------------------------------
>
> # Grid
>
> mol::ode_method = "RK4"
> mol::mol_intermediate_steps = 4
> mol::mol_num_scratch_levels = 1
>
>
>
> CoordBase::domainsize = "minmax"
> CoordBase::xmin = 0
> CoordBase::ymin = 0
> CoordBase::zmin = 0
> CoordBase::xmax = 10
> CoordBase::ymax = 10
> CoordBase::zmax = 10
> CoordBase::spacing = "numcells"
> CoordBase::ncells_x = 50
> CoordBase::ncells_y = 50
> CoordBase::ncells_z = 50
> CartGrid3D::type = "coordbase"
> CartGrid3D::domain = "full"
> CartGrid3D::bitant_plane = "xy"
> CartGrid3D::avoid_originx = no
> CartGrid3D::avoid_originy = no
> CartGrid3D::avoid_originz = no
>
> CoordBase::boundary_size_x_lower = 4
> CoordBase::boundary_size_y_lower = 4
> CoordBase::boundary_size_z_lower = 4
> CoordBase::boundary_shiftout_x_lower = 1
> CoordBase::boundary_shiftout_y_lower = 1
> CoordBase::boundary_shiftout_z_lower = 1
>
> CoordBase::boundary_size_x_upper = 4
> CoordBase::boundary_size_y_upper = 4
> CoordBase::boundary_size_z_upper = 4
>
> ReflectionSymmetry::reflection_x = yes
> ReflectionSymmetry::reflection_y = yes
> ReflectionSymmetry::reflection_z = yes
> ReflectionSymmetry::avoid_origin_x = no
> ReflectionSymmetry::avoid_origin_y = no
> ReflectionSymmetry::avoid_origin_z = no
>
>
>
> driver::ghost_size = 4
>
> #-----------------------------------------------------------