SMIwiz

SMIwiz is a C/MPI toolbox for acoustic seismic modelling, imaging, and inversion. It uses high-order staggered-grid finite-difference time-domain propagation and includes workflows for forward modelling, RTM, LSRTM, FWI, source estimation, migration deconvolution, and wavefield decomposition.

The repository contains the core solver, a small GTK launcher, reproducible synthetic examples, and reference materials for the published methods.

Scope

SMIwiz currently supports:

• 2D and 3D acoustic modelling on staggered grids
• Isotropic, VTI, and TTI model input paths
• Forward modelling and data generation
• Full waveform inversion (FWI) and gradient evaluation
• Reverse time migration (RTM)
• Data-domain least-squares RTM (LSRTM)
• Source inversion
• Angle-domain common-image-gather (ADCIG) extraction
• Point-spread-function (PSF) Hessian calculation
• Migration deconvolution with PSF-based PCGNR or FFT-Wiener filtering
• Up-going and down-going wavefield separation

Publications

If you use this code in research, cite the relevant paper(s):

• Pengliang Yang, “SMIwiz: An integrated toolbox for multidimensional seismic modelling and imaging”, Computer Physics Communications 295, 109011, 2024. DOI: 10.1016/j.cpc.2023.109011
• Zhengyu Ji and Pengliang Yang, “SMIwiz-2.0: Extended functionalities for wavefield decomposition, linearized and nonlinear inversion”, Computer Physics Communications 309, 109503, 2025. DOI: 10.1016/j.cpc.2025.109503
• Pengliang Yang and Zhengyu Ji, “A comparative study of data- and image-domain LSRTM under velocity-impedance parametrization”, Computers & Geosciences 208, 106091, 2026. DOI: 10.1016/j.cageo.2025.106091

Project talk: https://cassyni.com/events/P4W1QfiGXffuSf6Rv5VzJZ

Repository Layout

• src/: core C implementation and Makefile
• include/: public headers and shared data structures
• bin/: output directory for compiled executables
• doc/: papers and supporting technical references
• GUI/: GTK3 launcher for editing inputpar.txt and running jobs
• run_fwd/: minimal forward-modelling example
• run_fwi2d/: small 2D FWI example in a layered model
• run_marmousi/: 2D Marmousi FWI example
• run_rtm/: 2D RTM example
• run_lsrtm2d/: 2D two-parameter LSRTM example
• run_lsrtm3d/: 3D two-parameter LSRTM example
• run_decon_1par/: one-parameter migration deconvolution workflows
• run_updown/: up/down wavefield separation example
• run_fbrec3d/: 3D wavefield reconstruction example
• run_fwi3d/: 3D FWI example assets and survey generation
• run_fwd_aniso/: anisotropic forward-modelling example
• run_Viking/, run_Viking_85shots/: Viking Graben real-data workflows
• run_rwi_grad/: gradient-generation and related inversion experiments

Requirements

• Linux
• MPI compiler and runtime, typically OpenMPI or MPICH
• FFTW3 development libraries
• make
• Optional: gfortran for helper programs in some example directories
• Optional: GTK3 development packages for the GUI

Build

The main build uses mpicc and expects the FFTW installation prefix through the fftw3 environment variable.

export fftw3=/path/to/fftw3
cd src
make

This creates the solver at bin/SMIwiz.

If your MPI wrapper or FFTW location differs, adjust src/Makefile.

Running the Solver

SMIwiz is launched with MPI and a flat parameter list, usually generated from an inputpar.txt file:

mpirun -n <ranks> ../bin/SMIwiz $(cat inputpar.txt)

Most example directories already contain a run.sh or similarly named script that writes inputpar.txt and starts a job.

Main mode Values

The executable entry point in src/main.c dispatches work by mode=:

• 0: forward modelling
• 1: time-domain FWI
• 2: RTM
• 3: data-domain LSRTM
• 4: FWI gradient building
• 5: source inversion
• 6: ADCIG extraction
• 7: PSF Hessian computation
• 8: iterative migration deconvolution via PSF
• 9: migration deconvolution via FFT-Wiener filtering
• 10: up/down wavefield separation

Common Required Inputs

Most runs need at least:

• grid and time parameters: n1, n2, optional n3, d1, d2, optional d3, nt, dt
• acquisition description: acquifile=...
• model files: vpfile=..., rhofile=...
• source wavelet: stffile=... unless mode=5
• inversion or imaging options depending on the selected mode

Model files are read as binary float arrays with dimensions matching the declared grid size.

Quick Start

1. Build the executable

export fftw3=/path/to/fftw3
cd src
make

2. Run the small 2D FWI example

cd ../run_fwi2d
bash run.sh

That script writes inputpar.txt and launches:

mpirun -n 2 ../bin/SMIwiz $(cat inputpar.txt)

3. Run the 2D RTM example

cd ../run_rtm
bash run_rtm.sh

The RTM example is configured for a larger MPI job in the provided script, so adjust the mpirun -n value if your machine has fewer ranks available.

Example Notes

• run_fwi2d/ is the easiest place to start. It is small, self-contained, and shows the standard inputpar.txt workflow clearly.
• run_marmousi/ and run_fwd_aniso/ are useful for more realistic 2D tests and anisotropic inputs.
• run_decon_1par/ expects a staged workflow: first compute the PSF (mode=7), then run deconvolution with mode=8 or mode=9 depending on method.
• run_fbrec3d/ requires generating acqui.txt locally before running because the full file is too large to keep in the repository.
• run_Viking/ is the real-data workflow. Follow run_Viking/0_readme.txt for its step-by-step process.

GUI

The GTK launcher in GUI/ provides a simple interface for editing inputpar.txt, selecting the run directory, and launching mpirun.

Build and run it with:

cd GUI
make
./gui

See GUI/README.md for the current GUI behavior and requirements.

Reproducibility and Version Notes

A few examples refer to specific historical revisions in their local notes. If you are trying to reproduce figures from a paper exactly, check the run directory for version-specific instructions before changing scripts or parameters.

Contact

Pengliang Yang
Email: ypl.2100@gmail.com

License

This project is distributed under the GPL-3.0 license. See LICENSE.