  This paper contributes an open source software - SMIwiz, which integrates
seismic modelling, reverse time migration (RTM), and full waveform inversion
(FWI) into a unified computer implementation. SMIwiz has the machinery to do
both 2D and 3D simulation in a consistent manner. The package features a number
of computational recipes for efficient calculation of imaging condition and
inversion gradient: a dynmaic evolving computing box to limit the simulation
cube and a well-designed wavefield reconstruction strategy to reduce the memory
consumption when dealing with 3D problems. The modelling in SMIwiz runs
independently: each shot corresponds to one processor in a bijective manner to
maximize the scalability. A batchwise job scheduling strategy is designed to
handle large 3D imaging tasks on computer with limited number of cores. The
viability of SMIwiz is demonstrated by a number of applications on benchmark
models.
