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Tékigô

About

Tékigô is a python helper tool for static mesh adaptation. It eases the creation of metrics, and store them in a file. The online documentation is available on the internal Cerfacs forge (Credentials needed). Soon the package will be updated on pypi with documentation on readthedocs.

There is a built-in adaptation step done with HIP mesh handler developed at CERFACS. It is suited for unstructured grids and particularly useful for CFD.

Note : for now, Tekigo handle AVBP mesh and solution format. However contact us for extendion to others format, it should not be a big deal…

Installation

please install first pyHIP :

pip install pyhip

While we a refurbishing this new version 1.0, it will not be released on PyPI before we reach a stable version. Therefore, please, use tekigo from the sources:

git clone git@gitlab.com:cerfacs/tekigo.git

followed in the tekigo/ parent directory by:

 python setup.py install

If possible add pyavbpto your environement. This is not compulsory, but needed to create the xmffile from you ionitial mesh and solution. Learn more about COOP virtual environements in this blog post on COOP venvs

Basic usage:

Tekigo is used via python scripts, to do the following steps

  1. create a TekigoSolution, i.e. a mesh + solution with some additional fields (coordinates , volume at node).

  2. Load from this TekigoSolution some Quantities of Interests.

  3. Build a metric from these Quantities of Interests, using numpyformalism -and if neededsome tekigo utilities-.

  4. Evaluate the metric, i.e. forecast the future mesh : how many cells are we going to get?, what the fields will look like in the end?

  5. If asked, perform a HIP/MMG adaptation

The script reads:

import numpy as np
from tekigo import (TekigoSolution, adaptation_pyhip)

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


x_coor = tekigo_sol.load_qoi('/Mesh/coord_x')
metric_field = np.where(x_coor<0.1,1,0.7)

tekigo_sol.evaluate_metric(metric_field)

adaptation_pyhip(tekigo_sol, edge_low=1.e-3)

See tutorials for more in-depth description of scripts. No magic exxecution for the moment, create your python script and run it with

python my_tekigo_script.py

Performances

Tekigo’s adaptation_pyhip() through HIP/MMG, is sequential : do not aim for final meshes above 150M Tetrahedrons.. Around 200 MCells, you will reach the limits of a sequential mesh adapter. For larger cases, just use tekigo without the adaptation_pyhip() step, pass the solution to TreeAdapt. For the record, TreeAdapt needs the final edge lenght (field target_edge), not the metric(field metric).

Acknowledgements

Tekigo is the result of many discussions and developments of different contributors within the COOP team of CERFACS.

Tekigo is a service created in the COEC Center Of Excellence, funded by the European community.

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