Metadata-Version: 2.0
Name: empymod
Version: 1.4.4
Summary: Open-source full 3D electromagnetic modeller for 1D VTI media
Home-page: https://empymod.github.io
Author: Dieter Werthmüller
Author-email: dieter@werthmuller.org
License: Apache License V2.0
Download-URL: https://github.com/empymod/empymod/tarball/v1.4.4
Platform: UNKNOWN
Classifier: Development Status :: 5 - Production/Stable
Classifier: License :: OSI Approved :: Apache Software License
Classifier: Programming Language :: Python :: 3.4
Classifier: Programming Language :: Python :: 3.5
Classifier: Programming Language :: Python :: 3.6
Requires-Dist: numpy
Requires-Dist: scipy

empymod
=======

The electromagnetic modeller **empymod** can model electric or magnetic
responses due to a three-dimensional electric or magnetic source in a
layered-earth model with vertical transverse isotropic (VTI)
resistivity, VTI electric permittivity, and VTI magnetic permeability,
from very low frequencies (DC) to very high frequencies (GPR). The
calculation is carried out in the wavenumber-frequency domain, and
various Hankel- and Fourier-transform methods are included to transform
the responses into the space-frequency and space-time domains.

More information
----------------

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

.. code:: bash

    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.

.. code:: bash

    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**

   -  ``tdem`` (**TEM**) Issues that have to be adressed: ramp waveform,
      windowing, loop integration, zero-offset (coincident loop).

      -  in-loop
      -  coincident loop
      -  ...

   -  **Ramp waveform**
   -  **Arbitrary waveform**
   -  Improve the GPR-routine
   -  Load and save functions to easily store and load model information
      (resistivity model, acquisition parameters, and modelling
      parameters) together with the modelling data (using ``pickle`` or
      ``shelve``).

-  **Inversion**: Inversion routines, preferably a selection of
   different ones.

-  **Improve documentation**

   -  Move main part from ``empymod/__init__.py`` to ``docs/*.rst``
   -  Add actual equations, instead of only references to them
   -  Add general EM introduction and derivation
   -  Add a few simple example of its usage including figures
   -  Add more explanations regarding the different transforms

-  Additional (semi-)analytical functions (where possible)

   -  Complete full-space (electric and magnetic source and receiver);
      space-time domain
   -  Extend diffusive half-space solution to magnetic sources and
      receivers; space-frequency and space-time domains
   -  Complete half-space

-  Fourier transform

   -  Change ``fft`` to use discrete sine/cosine transforms instead, as
      all other Fourier transforms
   -  If previous step is successful, clean up the internal decisions
      (``utils.check_time``) when to use sine/cosine transform (not
      consistent at the moment, some choice only exists with ``ffht``
      impulse responses, ``fqwe`` and ``fftlog`` use sine for impulse,
      and all three use sine for step-on responses and cosine for
      step-off responses)

-  Hankel transform

   -  Add the ``fht``-module from FFTLog for the Hankel transform.

-  Module to design digital filters

   -  **Hankel transform** (almost ready)
   -  Extend to Fourier transform

-  Extend examples (example-notebooks)

   -  Add different methods (e.g. DC)
   -  Reproduce published results

-  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 (more relevant if once an inversion is
   implemented).

-  Move empymod from channel 'prisae' to 'conda-forge' (pros/cons?).

Citation
--------

If you publish results for which you used empymod, please give credit by
citing this article:

    Werthmüller, D., 2017, An open-source full 3D electromagnetic
    modeler for 1D VTI media in Python: empymod: Geophysics, 82,
    WB9-WB19; DOI:
    `10.1190/geo2016-0626.1 <http://doi.org/10.1190/geo2016-0626.1>`__.

Also consider citing 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 <http://doi.org/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 <http://doi.org/10.1190/geo2011-0237.1>`__.

All releases have a Zenodo-DOI, provided on the
`release-page <https://github.com/empymod/empymod/releases>`__.

Notice
------

This product includes software that was initially (till 01/2017)
developed at *The Mexican Institute of Petroleum IMP* (`Instituto
Mexicano del Petróleo <http://www.gob.mx/imp>`__). The project was
funded through *The Mexican National Council of Science and Technology*
(`Consejo Nacional de Ciencia y Tecnología <http://www.conacyt.mx>`__).
Since 02/2017 it is a personal effort, and new contributors are welcome!

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.


