Basic Waveform inversion
This software release includes a demonstration of the parallel waveform inversion framework in Matlab that has been developed at SLIM.
Author: Tristan van Leeuwen Date : May, 2012
Contents
Downloading & Dependencies
The code can be found in the SLIM sofware release under /applications/WaveformInversion/2DBasic.
The code has been tested with Matlab R2012b and requires the Parallel Computing Toolbox.
This code uses the following packages, also found in the tools part of the SLIM software release.
- utilities/SPOT - object oriented framework for matrix-free linear algebra.
- utilities/pSPOT - parallel extension of SPOT.
- algorithms/2DFreqModeling - 2D constant-density acoustic modeling
- operators/misc - Misc. operators such as interpolation, smoothing and splines
- functions/misc - Misc. functions.
Running & Parallelism
All the examples and results are produced by the scripts found in this software release under applications/WaveformInversion/2DBasic/. Start matlab from that directory or run startup in that directory to add the appropriate paths.
To run the scripts follow the instrictions in the README file enclosed with the code. The scripts can be run in serial mode but parallel mode is advised.
Read more about SLIM's approach to parallel computing in Matlab.
Functions
The functions specific to this package can be found in the mbin directory.
- twonorms - the two-norm and its derivative.
- Jls - least-squares residual and gradient for given model and observed data.
- mylbfgs - standard L-BFGS with Wolfe linesearch
More detailed descriptions and some basic tests are described here.
Examples and results
A script to reproduce the famous Camembert example [1] can be found in the scripts directory. The results are shown here.
References
[1] O. Gauthier, J. Virieux, and A. Tarantola. Two-dimensional nonlinear inversion of seismic waveforms: Numerical results. Geophysics 51, 1387-1403 (1986)