[Users] reduction in carpet + mismatched declaration in ML_ADMQuantities

[Hee Il Kim]

Hi,

Still I'm confused with the carpet reduction. The basic reduction method in
Christian's code was same with mine. But I thought what I did before should
be improved. First of all my expression "integration over only the coarsest
level" is very inaccurate. Anyway let me ask again.

What people do in reduction of , e.g. "Mass = Integration of density *
volume_measure" is;

------  Method I --------
* In local mode at mol_pseudoevolution or poststep
define Integrand = density      ! note it's not "density * volume_measure"

* In global mode at analysis
CCTK_Reduce(Integrand --> Mass_temp)
Mass = Mass_temp * product(cctk_delta_space)
------------------------------

Why do people define "integrand = density" not as "density *
volume_measure"? However, if i do take the latter, then I get very weird
result, so people might have not taken that. To my understanding, the above
Method I will produce;

Result I: Mass = (Sum_reflev=0 of capret weighted density(i,j,k) * dV_0) +
(Sum_reflev=1 of carpet weighted density(i,j,k) * dV_0) + ...

But what I wanted (expected) to get by defining integrand = density *
volume_measure" is more accurate one;

Result II: Mass = (Sum_reflev=0 of carpet weighted density(i,j,k) * dV_0) +
(Sum_reflev=1 of carpet weighted density(i,j,k) * 1/8 * dV_0) + ...

What is the above Method I doing for? Result I or Result II, or something
else?
The new reduction API mentioned in the reference manual is still
underdevelopment?

Thanks in advance,

Hee Il



2011/1/6 Hee Il Kim <heeilkim at gmail.com>

> Christian, thanks so much !
>
> Your code seems to contain everything I wanted to calculate.
>
> There's one minor mismatched declaration in ML_ADMQuantities which should
> be fixed anyhow.
>
> ####
>
> [khi at zenith src]$ diff ML_ADMQuantities.c.ori ML_ADMQuantities.c
> 56c56
> <   const char *groups[] =
> {"grid::coordinates","Grid::coordinates","McLachlan::ML_curv","McLachlan::ML_Gamma","McLachlan::ML_lapse","McLachlan::ML_log_confac","McLachlan::ML_metric","McLachlan::ML_shift","McLachlan::ML_trace_curv","ML_ADMQuantities::ML_Jadm","ML_ADMQuantities::ML_Madm"};
> ---
> >   const char *groups[] =
> {"grid::coordinates","Grid::coordinates","ML_BSSN::ML_curv","ML_BSSN::ML_Gamma","ML_BSSN::ML_lapse","ML_BSSN::ML_log_confac","ML_BSSN::ML_metric","ML_BSSN::ML_shift","ML_BSSN::ML_trace_curv","ML_ADMQuantities::ML_Jadm","ML_ADMQuantities::ML_Madm"};
>
> ####
>
> Thanks again,
>
> Hee Il
>
> 2011/1/5 Christian D. Ott <cott at tapir.caltech.edu>
>
>>
>> Dear Hee Il,
>>
>> I agree that getting this right is tricky. You must set up your grid
>> functions that you want to reduce in MoL_PseudoEvolution in local
>> mode, then do the reduction in CCTK_Analysis in global mode.
>>
>> I am attaching a Thorn called ZelmaniAnalysis that I use for the
>> kinds of things you want. The reduction works with Carpet.
>>
>> Best,
>>
>>  - Christian
>>
>>
>>
>> On Wed, Jan 05, 2011 at 09:18:21PM +0900, Hee Il Kim wrote:
>> > Hi,
>> >
>> > Belated Happy New Year !
>> >
>> > I am writing a simple code for the calculation of ADM mass and angular
>> > momentum by using ML_ADMQuantities. As you know,  it requires reduction
>> > procedure for the summation of the integrand, e.g., density * volume
>> > measure. I've tried various reduction APIs including old deprecated one,
>> but
>> > I could only succeed in the integration only over the coarsest grid
>> level,
>> > which was not accurate.
>> >
>> > If I use the new reduction API in the reference manual of Cactus,
>> > CCTK_ReduceGridArrays;
>> >
>> > CCTK_ReduceGridArrays(const cGH *GH,
>> > int dest_processor,
>> > int local_reduce_handle,
>> > int param_table_handle,
>> > int N_input_arrays,
>> > const CCTK_INT input_array_variable_indices[],
>> > int M_output_values,
>> > const CCTK_INT output_value_type_codes[],
>> > void* const output_values[]);
>> >
>> > , I encounter the following error
>> > ....
>> > WARNING[L3,P0] (Cactus): CCTK_ReduceGridArrays: no grid array reduction
>> > registered
>> > WARNING level 0 in thorn ML_Analysis processor 0 host compute-0-5.local
>> >   (line 159 of Evaluate_ADMQuantities.F90):
>> >   -> Failed to integrate J_z
>> >
>> > Param_table_handle is not clear to me but it seems not causing the
>> problem.
>> > The reduction operators are registered by CactusBase/LocalReduce.
>> >
>> > Could you let me know which reduction function I have to use for this
>> > calculation? I mean the integration over the whole grid levels. Should I
>> do
>> > loop over refinenment levels;
>> > ...
>> > do loop over reflev
>> >   call CCTK_Reduce
>> > enddo
>> > ...
>> >
>> > Thanks in advance,
>> >
>> > Hee Il
>>
>> > _______________________________________________
>> > Users mailing list
>> > Users at einsteintoolkit.org
>> > http://lists.einsteintoolkit.org/mailman/listinfo/users
>>
>>
>
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