High‐Speed Computation and Efficient Storage in 3‐D Gravity and Magnetic Inversion

There is a method which makes regular subdivision of the source region into a set of juxtaposed cuboids and estimation of physical properties of the cuboids using an inversion of potential field to deduce the image of the geological sources. It is currently prevailing in geophysical interpretation, especially in 3-D gravity and magnetic inversion. Nonlinear global methods, such as the Genetic Algorithms, gradually play a leading role in the inversion. This paper shows that there exists an excessive computation that has bottlenecked the effectiveness of nonlinear global methods including the Genetic Algorithms. Several special tricks are proposed to break the choke point of overwhelming computation, one of which is to separate the geometric trellis from formulas. The trellis is invariable during the whole process of inversion, and stored as a table, which would make the following reiterative forward computation as just a simple reading of the table and multiplying it with corresponding properties of the geometric cells. The required huge storage of geometric trellis has been tremendously reduced by a very skill of equivalent storing. The approaches revive the nonlinear methods in their applications to the inversion of gravity and magnetic anomalies for 3-D physical properties.

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