# Set your own settings for your simulations¶

The input of stellacode is a config file with INI text-structure. This file contain all the numerical parameters and a link to the surfaces files and the bnorm file.

## the config file¶

```
[geometry]
np = 3 # The number of discrete symmetry needed to obtain the full torus
ntheta_plasma = 64 # nb of toroidal points of the plasma used numerically (on one section)
ntheta_coil = 64 # nb of toroidal points of the CWS used numerically (on one section)
nzeta_plasma = 64 # nb of poloidal points of the plasma used numerically
nzeta_coil = 64 # nb of poloidal points of the plasma used numerically
mpol_coil = 12 # higher order of the Fourier harmonics in the toroidal(?) direction
ntor_coil = 12 # higher order of the Fourier harmonics in the poloidal(?) direction
path_plasma = data/li383/plasma_surf.txt
path_cws = data/li383/cws.txt
[other]
path_bnorm = data/li383/bnorm.txt
net_poloidal_current_amperes = 11884578.094260072
net_toroidal_current_amperes = 0.
curpol = 4.9782004309255496 # an unknown constant in front of bnorm...
path_output = with_curv # output folder
lamb = 2.5e-16 # lambda used in EM cost for the Tychonov regularization
dask = True # Do not change
cupy = False # Do not change
[dask_parameters] # chunk for dask, do not modify if you do not know what you are doing
chunk_theta_coil=32
chunk_zeta_coil=32
chunk_theta_plasma=32
chunk_zeta_plasma=32
chunk_theta=17
[optimization_parameters] # The important section ;-)
freq_save=100 #
max_iter=2000 # number of iteration of the optimization algorithm (lower than the number of cost call)
d_min=True # penalize low distance to plasma
d_min_hard = 0.18 # wall
d_min_soft= 0.20 # beginning of the penalization
d_min_penalization=1000 # constant factor, a priori not very useful
perim=True # penalization of the perimeter
perim_c0=56 # beginning of the penalization
perim_c1=60 # wall
curvature=True # penalization of the inverse of the curvature radii
curvature_c0=13 # beginning of the penalization
curvature_c1=15 # beginning of wall
```

- Note that the unit of the different quantities are
Ampere (A) for the currents

unknown for curpol…

metter (m) for the distance to the plasma

metter square (m^2) for the perimeter

inverse of the metter (m^-1) for the curvature (i.e. principal curvatures)

## the surface files¶

The surface files have the form :

```
0 0 1.3278E+00 0.0000E+00
0 1 4.2527E-03 -2.4153E-02
0 2 4.6118E-05 -9.3831E-03
0 3 7.1383E-03 3.4517E-03
0 4 5.0157E-03 2.3650E-03
0 5 1.6390E-03 9.4419E-04
0 6 -2.4003E-04 -9.4647E-04
0 7 -1.2541E-04 1.8339E-04
```

where for each row we have

```
m n Rmn Zmn
```

## the bnorm file¶

the bnorm file has a similar structure

```
0 -24 1.7668311833075789E-11
```

where for each row we have

```
m n Bmn
```