Users wanting to use SDPM for standard computations, or interface it with external software should use one of the available APIs or write their own. The following APIs are available:
* Core
* OMFlut
_Note_ the different APIs automate the creation of the mesh, the problem and the solvers, and provide methods for performing specific tasks. These APIs are available under [api](https://gitlab.uliege.be/am-dept/sdpm/blob/master/sdpm/api) and share a common base: [core](https://gitlab.uliege.be/am-dept/sdpm/blob/master/sdpm/api/core.py).
### Core
The [core](https://gitlab.uliege.be/am-dept/sdpm/blob/master/sdpm/api/core.py) API is the common base of all APIs. It simply consists in a `init_sdpm` method which will return all the C++ objects wrapped in python required to run SDPM. If a new API is created, it should initialize itself by calling this method.
SDPM is initialized by using a dictionary of parameters, and the type of scenario and task. The different parameters are listed hereunder:
```python
cfg={
# Model (geometry or mesh)
'File':str,# input Gmsh file
'Pars':dict,# parameters for Gmsh file (optional)
# Markers
'Wing':str,# name of the marker defining the lifting body (wing)
'Te':str,# name of the marker defining the trailing edge of the lifting body
# Freestream
'Mach':float,# Mach number (optional)
'AoA':float,# angle of attack (optional)
'AoS':float,# angle of side slip (optional)
# Unsteady motion
'Num_wake_div':int,# number of cells per chord length in the wake
'Frequencies':array[float],# list of reduced frequencies
'Modes':str,# input file containing the modes (optional)
'Num_modes':int,# number of modes
# Transonic correction
'Transonic_pressure_grad':str,# input file containing the pressure derivative (optional)
# Geometry
'Symmetry':bool,# whether only half (symmetric) model is provided
's_ref':float,# reference surface area
'c_ref':float,# reference chord length
'x_ref':float,# reference point for moment computation (x)
'y_ref':float,# reference point for moment computation (y)
'z_ref':float# reference point for moment computation (z)
}
```
Once the parameters have been defined, SDPM can simply be initialized by calling,
```python
fromsdpm.api.coreimportinit_sdpm
_sdpm=init_sdpm(cfg,use_ad=False)
```
where `use_ad` indicates whether the adjoint sovler must be instantiated or not. `_sdpm` is a dictionary containing the following objects (named after their key):
*`n_f` is the number of reference reduced frequencies
*`n_m` is the number of modes
*`msh` is the mesh
*`wrt` is the utility to write mesh/results on disk
*`pbl` is the formulation of the problem
*`bdy` is the body of interest
*`sol` is the direct solver
*`adj` is the adjoint solver
### OMFlut
SDPM has been interfaced with [OMFlut](https://gitlab.uliege.be/am-dept/omflut), which is built on top of [OpenMDAO](https://openmdao.org/), in order to calculate flutter. SDPM must be initialized inside an OpenMDAO group using a builder which will latter be reused by OMFlut.
