Unsderstanding the tekigoSolution object

What is it?

A tekigoSolution object is an unstructured mesh, plus fields on the mesh. This object is an interface to an actual set of three files stored on your hard drive. Theses files are usually:

Results/
├── tekigo_init.mesh.h5
├── tekigo_init.sol.h5
└── tekigo_init.sol.xmf

Therefore, if you add a field new_field in a python interactive script using tekigoSolution, the files on the disc .sol.h5 and .sol.xmf are immediately updated. Reloading the solution from your fieldviewer (Paraview, Ensight, Tecplot) will make this new_field appear.

Creation

Create your object as follows:

from tekigo import TekigoSolution

tekigo_sol = TekigoSolution(
    mesh='../../GILGAMESH/trapvtx/trappedvtx.mesh.h5',
    solution='combu.init.h5',
    out_dir='./Results')

In the log file, and the standard input, the object will react like this:

======= Creating TekigoSolution handler... =========


   Inital mesh:
   Number of nodes     34684
   Number of cells     177563
   Minimal edge size   1.08462e-03

 The following Quantities of Interest can be loaded: 
 - /Additionals/pressure
 - /Additionals/temperature
 - /GaseousPhase/rho
 - /GaseousPhase/rhoE
 - /GaseousPhase/rhou
 - /GaseousPhase/rhov
 - /GaseousPhase/rhow
 - /Mesh/coord_x
 - /Mesh/coord_y
 - /Mesh/coord_z
 - /Mesh/init_edge
 - /Mesh/volume
 - /RhoSpecies/CO
 - /RhoSpecies/CO2
 - /RhoSpecies/H2O
 - /RhoSpecies/KERO_LUCHE
 - /RhoSpecies/N2
 - /RhoSpecies/O2

The role of the initial solution?

The initial solution is highly recommended, because at the end of the day you want to run a simulation. If you provide the solution at the very end of the process, the new mesh, old mesh and solution must be loaded in memory for an interpolation. This step is often very heavy for adapted large meshes.

One can easily skip this unecessary loading time by providing the solution at the debinning of the process. Indeed, the mesh adaptation require new mesh, old mesh and at least a metric. Most of the I/O is eventually done in this first step anyway.

But if you reallllly do not want to provide a solution, set it to, None.

Skip additionals

The additionals fields can make the solution very heavy. You can skip them with: TekigoSolution(..., additionals=False).

Loading a field

You can load any field by name into the tekigo solution as follows.

x_coor = tekigo_sol.load_qoi('/Mesh/coord_x')

The resulting output is a numpy array with the shape of the mesh.

Adding a field from a numpy array

You can add a field anytime in the object:

 tekigo_sol.add_field_to_solmesh("foo", foo_array)

This is adding the field /Adapt/foo in the solution.

The group destination is by default Adapt but can be overidden, i.e. for /Custom/foo use:

 tekigo_sol.add_field_to_solmesh("foo", foo_array, group='Custom")

Adding a field from an HDF5 solution

Fields can be loaded from an existing solution file with:

tekigo_sol.add_fields_from_solution('combu.init.h5', "RhoSpecies", ["CO","CO2"])

Note this works for any number of solutions , instantaneous or averages. You can therefore mix fields coming from various files with this.

Setting the metric for adaptation

As the only objective of tekigo is mesh adaptation, the method .evaluate_metric() is adding two fields:

/Adapt/target_edge is the estimated edge size after adaptation. This quantity is used for example as the input for the parallel adpation tool TreeAdapt.
/Adapt/metric is the ratio of the edge final size /Adapt/target_edge, over the initial size /Mesh/init_edge. This quantity is used for example as the input for the parallel adpation tool pyHip.

When called this method also gives some global information on the current adpatation metric:

======= Evaluate metric w.r. to solution =========


   Field Custom metric : 0.5000, 1.0000

   Forecast mesh:
   Number of nodes     36315
   Number of cells     185912
   Minimal edge size   9.44140e-04

The gather scatter method()

The .gatherscatter() method returns an object to apply some advanced connectivity-based operations (closure, smoothing). Read more in the how-tos.