Leesa Brieger

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The geophysics group at CRS4 has long developed echo reconstruction codes in HPF on distributed-memory machines. Now, however, with the arrival of shared-memory machines and their native OpenMP compilers, the transfer to OpenMP would seem to present the logical next step in our code development strategy. Recent experience with porting one of our important(More)
Echo-reconstruction techniques for non-intrusive imaging have wide application, from subsurface and underwater imaging to medical and industrial diagnostics. The techniques are based on experiments in which a collection of short acoustic or electromagnetic impulses, emitted at the surface, illuminate a certain volume and are backscattered by inhomogeneities(More)
Parallel preconditioners are considered for improving the convergence rate of the conjugate gradient method for solving sparse symmetric positive deenite systems generated by nite element models of subsurface ow. The diiculties of adapting eeective sequential preconditioners to the parallel environment are illustrated by our treatment of incomplete Cholesky(More)
Comparative studies of methods of reverse time migration (RTM) show that spectral methods for calculating the Laplacian impose the least stringent demands on discretization stepsize; thus with spectral methods, the grid reenements often required by other methods can be avoided. Implemented with absorbing boundary conditions , which are energy-tuned to give(More)
The data-parallel programming paradigm emerges as the natural choice for a large class of scientiic applications. One of its most signiicant features consists in hiding the details of the communications and synchronizations among processors, leaving them to the compiler. The advent of the new standard data-parallel language, High Performance Fortran (HPF),(More)
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