About Aegis Geophysics

Aegis Geophysics is a consultancy specialising in forward and inverse modelling of airborne, ground and downhole electromagnetic survey data for minerals and groundwater exploration.

Forward modelling is an effective means to aid understanding of the interaction of a survey system with a target.

Inverse modelling is a useful lense through which to interpret field data.

Aegis Geophysics offers expert instruction in the use of the P223 codes.  However, we prefer to use and develop more modern alternatives.

Aegis Geophysics is owned by Dr David Annetts.

Modernisation of the P223 codes

The P223 codes were developed by CSIRO with industry assistance over the course of several AMIRA projects.  They were placed into the public domain in 2008.

Although the original codes are reasonably robust, they are very much of a time and this limits the degree to which they can be effectively maintained and developed.

Aegis Geophysics has taken the initiative and commenced their modernisation. Because this requires rewriting rather than translation, the modernisation process will not be a short one.

Results (left) suggest that rewriting codes in Julia using structured programming techniques and modern data structures is effective. A comparison of run times between a modern F90 code and the current version of lyr.jl suggests that the Julia version is nearly 50% faster than the F90 code and has lower runtime variability.

The rewritten code is more versatile, robust, efficient and accurate than the original. The code is considerably simpler and therefore will be easier to maintain and extend. Other advantages of the rewritten code are summarised here.

Please contact Aegis Geophysics for further details about the motivation behind the process as well as what has been done so far.