This library performs two-dimensional modeling and inversion of seismic data using fourth-order summation-by-parts finite-difference operators on a regular cartesian grid. Four main configurations are available: acoustic (variable density), elastic isotropic, elastic VTI, and isotropic acoustic-elastic coupled medium with a flat interface. Auxiliary programs are also provided such as wavelet generation, spectra computation, B-spline smoothing etc ...
Key features include:
- incorporated linear and non-linear solvers (including non-linear CG and l-BFGS)
- many practical options for full-waveform inversion (FWI)
- auxiliary programs such as wavelet generation, spectra computation, B-spline smoothing etc ...
- MPI support for parallelization over shots
- GPU acceleration with CUDA (currently for the elastic isotropic and VTI configurations only)
Start by cloning the current repository
git clone https://github.com/nmbader/fwi2d.git
cd fwi2d
Build the docker image (it should take a few minutes)
docker build -f Dockerfile -t fwi2d .
Run a container
docker run -it -p 8080:8080 fwi2d
By default a bash shell will be opened at /home inside the container. Run jupyter notebook from within the container
jupyter notebook --ip 0.0.0.0 --port 8080 --no-browser --allow-root &
Open the browser at localhost:8080/ and use the printed token above to authenticate.
The image will build the fwi2d library in single precision with CUDA disabled.
The fwi2d library is written almost entirely in C++ and CUDA and has been built on Linux environments (centos 7) using CMAKE. The FFTW3 library is required. A portion of the code is compiled using ISPC which needs to be installed a priori. Downloading the binary directly from here should suffice. Moreover, Python and Jupyter are only required for data format conversion and examples generation.
Start by downloading ISPC binary (or building it from source code) and copying it to the desired location path_to_ispc_binary
# for Linux 64 bit
wget https://github.com/ispc/ispc/releases/download/v1.17.0/ispc-v1.17.0-linux.tar.gz
tar -xvf ispc-v1.17.0-linux.tar.gz
cp ispc-v1.17.0-linux/bin/ispc path_to_ispc_binary/ispc
Then clone and install the main fwi2d library
# get the code
git clone https://github.com/nmbader/fwi2d.git
cd fwi2d
# create subdirectories
mkdir build local
# Build the external SEPlib library needed for the IO
cd external/SEP
bash ./buildit.sh
# When it is done, build the main library
cd ../../build
cmake -DCMAKE_INSTALL_PREFIX=../local -DISPC_PATH=path_to_ispc_binary/ispc ../
make -j12
make install
# clean up the build directory
rm -rf *
By default, the fwi2d library is built in single precision. For double precision, add the flag -DENABLE_DOUBLE_PRECISION=1
to the cmake command.
All executables (and python scripts) will be installed into the subdirectory fwi2d/local/bin. It will be more convenient to add this path to the environment variable PATH in order to run the examples seeminglessly.
If the host machine has CUDA enabled, add the flag -DENABLE_CUDA=1. In this case, the wave propagation and inversion executables will expect an available GPU device. It is recommended to install the CUDA enabled code in a separate location (e.g. fwi2d/local_gpu) so that the CPU-only code can still be used.
MPI is also available for parallelization over seismic sources. If CMAKE cannot locate an MPI installation automatically, add the corresponding path manually by setting the flag -DCMAKE_PREFIX_PATH=path_to_mpi_directory. Otherwise, MPI will be deactivated.
By default, the main executables read and write data in SEPlib format (with little-endian binaries). Alternatively, native binary format is also accepted provided that a description file is built. A C++ executable is provided to convert between these two formats. Moreover, a python script is provided to convert to/from SEPlib from/to numpy, and a python class to write and read directly from python to SEPlib.
Refer to the examples for simple modeling and inversion tests.