empymod 1.4.0

More information

For information regarding installation, requirements, documentation, examples, contributing and so on: empymod.github.io.

Installation from source

You can clone or download the latest version from GitHub and either add the path to empymod to your python-path variable, or install it in your python distribution via:

python setup.py install

Testing

The modeller comes with a test suite using pytest. If you want to run the tests, just install pytest and run it within the empymod-top-directory.

pytest

Pytest will find the tests, which are located in the tests-folder. It should run all tests successfully. Please let me know if not!

Note that installations of empymod via conda or pip do not have the test-suite included. To run the test-suite you must download empymod from GitHub.

Roadmap

A collection of ideas of what could be added or improved in empymod. Please get in touch if you would like to tackle one of these problems!

• Additional modelling routines:

  • Ramp waveform

  • Arbitrary waveform

  • TEM (in-loop, coincident loop, …): the problems to tackle are mainly zero-offset, loop integration, and windowing.

  • Improve the GPR-routine

  • Load and save functions to store and load model information (resistivity model, acquisition parameters, and modelling parameters) together with the modelling data.

• Additional analytical functions (semi-analytical); if possible

  • Complete fullspace (el./mag. src/rec); space-time domain

  • Extend diffusive halfspace solution to magnetic sources and receivers; space-frequency and space-time domains

  • Complete halfspace

• Extend ``fQWE`` and ``fftlog`` to use cosine: At the moment, fqwe and fftlog are implemented with the sine-transform. It would not be too much work to make them flexible to handle sine- and cosine-transforms. Having this flexibility we could calculate the step-off response with the cosine versions of fftlog, fqwe, and ffht instead of subtracting the step-on from the DC value. (Check how it works with fft!)

• Module to design digital filters

  • Hankel transform (almost ready)

  • Extend to Fourier transform

• Inversion: Inversion routines, preferably a selection of different ones.

• Improve documentation

  • Add actual equations, instead of only references to them.

• Extend examples (example-notebooks); reproduce published results

  • Clean-up!

  • Move comparing.ipynb to tests-functions

  • Schlumberger, Wenner

  • CSEM

  • MTEM

  • DC

  • TEM

  • GPR

  • EM31

  • …

• A cython, numba, or pure C/C++ implementation of the kernel and the transform modules. Maybe not worth it, as it may improve speed, but decrease accessibility. Both at the same time would be nice. A fast C/C++-version for calculations (inversions), and a Python-version to tinker with for interested folks. (Probably combined with default parallelisation, removing the numexpr variant.)

• Abstraction of the code.

• GUI.

• Add a benchmark suite, e.g. http://asv.readthedocs.io, in addition to the testing suite.

• Add some clever checks, e.g. as in Key (2012): abort loops if the field is strongly attenuated.

Citation

I am in the process of publishing an article in Geophysics regarding empymod, and I will put the info here once it is a reality. If you publish results for which you used empymod, please consider citing this article. Meanwhile, you could cite the Geophysical Tutorial:

Werthmüller, D., 2017, Getting started with controlled-source electromagnetic 1D modeling: The Leading Edge, 36, 352-355; DOI: 10.1190/tle36040352.1.

Also consider citing the two articles given below, Hunziker et al. (2015) and Key (2012), without which empymod would not exist:

Hunziker, J., J. Thorbecke, and E. Slob, 2015, The electromagnetic response in a layered vertical transverse isotropic medium: A new look at an old problem: Geophysics, 80, F1-F18; DOI: 10.1190/geo2013-0411.1.

Key, K., 2012, Is the fast Hankel transform faster than quadrature?: Geophysics, 77, F21-F30; DOI: 10.1190/GEO2011-0237.1.

All releases have additionally a Zenodo-DOI, provided on the release-page.

Notice

This product includes software that was initially (till 01/2017) developed at The Mexican Institute of Petroleum IMP (Instituto Mexicano del Petróleo). The project was funded through The Mexican National Council of Science and Technology (Consejo Nacional de Ciencia y Tecnología).

License

Copyright 2016-2017 Dieter Werthmüller

Licensed under the Apache License, Version 2.0 (the “License”); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

See the LICENSE-file in the root directory for a full reprint of the Apache License.