ALGEBRAIC MULTIGRID METHOD FOR 3D DC RESISTIVITY MODELLING

Multigrid method is of high numerical efficiency in solving linear equations arisen from boundary value problem of partial differential equation (PDE). The usual geometrical multigrid has some defects which restrict its application in PDE with jumping coefficient. In this paper, algebraic multigrid (AMG) method is used to solve finite difference linear equations which are derived from 3D DC resistivity modelling. We solve the secondary potential to remove the singularity of the primary potential caused by source current, resulting in an accurate 3D resistivity modelling. Two models with high conductivity contrast are used to demonstrate convergence and efficiency of the AMG method. Our results show that AMG methods are very efficient and robust in comparison with incomplete cholesky conjugate gradient (ICCG) methods. Moreover, the AMC, method becomes more efficient as the number of 3D grid nodes increases.