An efficient parabolic equation solution based on the method of undetermined coefficients

An implementation of the self-starter based on the method of undetermined c oefficients is described and tested. For many problems, this parabolic equa tion technique for solving short range propagation problems provides an eff iciency gain of an order of magnitude or more over the finite difference so lution. With this forward model, it is possible to solve geoacoustic invers e problems in seconds on the current generation of desktop computers. The a pproach can be implemented for the inverse problem so that efficiency is es sentially independent of the depth of the water column. [S0001-4966(99)0261 0-7].