Tomofast-x v.2.0

A parallel inversion code for 3D geophysical potential field data, supporting joint and constrained inversion.
Authors: Vitaliy Ogarko, Jeremie Giraud, Roland Martin, Kim Frankcombe, Taige Liu

Tomofast-x is a powerful 3D parallel inversion platform designed for single-domain or joint inversion of gravity and magnetic data. It also supports the inversion of gravity gradiometry data (FTG) and can handle multiple-component magnetic data. The platform is capable of inverting for the magnetization vector, including remanence, while incorporating petrophysical constraints.

Optimized for both shared and distributed memory systems, Tomofast-x can run in parallel on desktops and supercomputers, ensuring scalability across different computing environments. It also features parallel wavelet compression of the sensitivity kernel, reducing memory usage and enhancing performance. Furthermore, Tomofast-x supports the inversion of models with arbitrary surface topography, making it highly versatile for various geological scenarios.

Citing Tomofast-x

If you use the code (or any of its components), please cite the following two papers, which provide detailed explanations of Tomofast-x's geophysical calculations and examples of its application:

• V. Ogarko, K. Frankcombe, T. Liu, J. Giraud, R. Martin, and M. Jessell (2024), "Tomofast-x 2.0: an open-source parallel code for inversion of potential field data with topography using wavelet compression", Geosci. Model Dev., 17, 2325–2345, https://doi.org/10.5194/gmd-17-2325-2024

• J. Giraud, V. Ogarko, R. Martin, M. Jessell, and M. Lindsay (2021), "Structural, petrophysical, and geological constraints in potential field inversion using the Tomofast-x v1.0 open-source code", Geosci. Model Dev., 14, 6681–6709, https://doi.org/10.5194/gmd-14-6681-2021

Compiling and running

To compile the code you need: GCC or Intel compiler, and the MPI library (such as OpenMPI).

The Makefile is located in the root folder and is used to compile Tomofast-x. Compilation is a required step before running inversions. To compile the code, navigate to the code directory and run the following command:

make

To run the code with your parameter file:

mpirun -np <Number-of-cores> ./tomofastx -j <Parfile path>

To run unit tests (serial and parallel):

./runtests.sh
mpirun -np 3 ./runtests.sh

Running the examples

The input data is contained in the folder data.
The input parameter file (Parfile) which contains all the parameters of the inversion, is stored in the folder: parfiles.
The output data is stored in the folder output. The full output folder path is specified in the Parfile parameter global.outputFolderPath.

To run the test example:

./tomofastx -j ./parfiles/Parfile_mansf_slice.txt

If the code runs successfully you will see in the end of the screen log the messages "Writing the full model...", and "THE END". To visualize the final model, open in Paraview the file Paraview/grav_final_model3D_full.vtk, located in the output folder. For details on other output files, see the User Manual in the docs folder.

Publications using the code

• V. Ogarko, K. Frankcombe, T. Liu, J. Giraud, R. Martin, and M. Jessell (2024), "Tomofast-x 2.0: an open-source parallel code for inversion of potential field data with topography using wavelet compression", Geosci. Model Dev., 17, 2325–2345, https://doi.org/10.5194/gmd-17-2325-2024

• J. Giraud, H. Seillé, M. Lindsay, G. Visser, V. Ogarko, and M. Jessell (2023), "Utilisation of probabilistic magnetotelluric modelling to constrain magnetic data inversion: proof-of-concept and field application", Solid Earth, 14, 43–68, https://doi.org/10.5194/se-14-43-2023

• J. Giraud, V. Ogarko, R. Martin, M. Jessell, and M. Lindsay (2021), "Structural, petrophysical, and geological constraints in potential field inversion using the Tomofast-x v1.0 open-source code", Geosci. Model Dev., 14, 6681–6709, https://doi.org/10.5194/gmd-14-6681-2021

• V. Ogarko, J. Giraud, R. Martin, and M. Jessell (2021), "Disjoint interval bound constraints using the alternating direction method of multipliers for geologically constrained inversion: Application to gravity data", GEOPHYSICS 86: G1-G11, https://doi.org/10.1190/geo2019-0633.1

• R. Martin, J. Giraud, V. Ogarko, S. Chevrot, S. Beller, P. Gégout, M. Jessell (2021), "Three-dimensional gravity anomaly data inversion in the Pyrenees using compressional seismic velocity model as structural similarity constraints", Geophysical Journal International 225(2): 1063–1085, https://doi.org/10.1093/gji/ggaa414

• M. Rashidifard, J. Giraud, M. Lindsay, M. Jessell, and V. Ogarko (2021), "Constraining 3D geometric gravity inversion with a 2D reflection seismic profile using a generalized level set approach: application to the eastern Yilgarn Craton", Solid Earth, 12, 2387–2406, https://doi.org/10.5194/se-12-2387-2021

• J. Giraud, M. Lindsay, M. Jessell, and V. Ogarko (2020), "Towards plausible lithological classification from geophysical inversion: honouring geological principles in subsurface imaging", Solid Earth, 11: 419–436, https://doi.org/10.5194/se-11-419-2020

• J. Giraud, M. Lindsay, V. Ogarko, M. Jessell, R. Martin, and E. Pakyuz-Charrier (2019), "Integration of geoscientific uncertainty into geophysical inversion by means of local gradient regularization", Solid Earth, 10: 193–210, https://doi.org/10.5194/se-10-193-2019

• J. Giraud, V. Ogarko, M. Lindsay, E. Pakyuz-Charrier, M. Jessell, R. Martin (2019), "Sensitivity of constrained joint inversions to geological and petrophysical input data uncertainties with posterior geological analysis", Geophysical Journal International, 218(1): 666–688, https://doi.org/10.1093/gji/ggz152

• R. Martin, V. Ogarko, D. Komatitsch, M. Jessell (2018), "Parallel three-dimensional electrical capacitance data imaging using a nonlinear inversion algorithm and Lp norm-based model regularization", Measurement, 128: 428-445, https://doi.org/10.1016/j.measurement.2018.05.099

Authors and contacts

Vitaliy Ogarko, Jeremie Giraud, Roland Martin, Kim Frankcombe, Taige Liu

For questions, contact Vitaliy Ogarko via [email protected]

License

Tomofast-x code is licensed under the MIT license. We request users to acknowledge the usage of Tomofast-x and to cite the relevant work.

Acknowledgments

The authors acknowledge Mark Jessell, Mark Lindsay, Dimitri Komatitsch, Kim Frankcombe, and Taige Liu.