[Users] Poisson equation

Taishi Ikeda taishi.ikeda at tecnico.ulisboa.pt
Thu Oct 15 05:15:28 CDT 2020


Dear all
Hello, I’m a user of EinsteinToolkit.
Now, I’m trying to solve Poisson's equation using ctthorn as initial data before time evolution on EinsteinToolkit.
The boundary condition is 1/r.

I already implemented my thorns for the source term of the equation,
and solved the equation using "CT_MutiLevel”.
I checked if the final solution is good solution of the original equation, but
it is not good solution.
I changed the resolution, but it is not improved.

So, I may misunderstand how to use CT_MutiLevel thorns, and I have questions relate to "CT_MutiLevel" :
1)
In order to understand correct behavior, 
I want to try test simulation using poisson.par, which is one of the example parameter file.

But, it does not work.
The output told me the grid structure is inconsistent,
and I also try another example, but it also has same error.
Are there other available par file for CT_MutiLevel ?

2)
To solve the elliptic equation with 1/r boundary condition, is CT_MutiLevel the best way ?
If there are another thorn to solve elliptic equation in EinsteinToolkit, please tell me.
Since I want to use Carpet, the thorn should be compatible with Carpet.

3)
After solving elliptic equation, I want to solve time evolution.
Since CT_MutiLevel is a solver using MultiGrid method, we must prepare several Carpet grids on whole domain.
But, is it consist with time evolution ?
If there is an example par file, let me know.

Best regard.
Taishi.

************************************
Taishi Ikeda
Physics Department
Sapienza University of Rome (Italy)
taishi.ikeda at uniroma1.it
************************************

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