Three-dimensional gravity and gravity tensor rapid forward modeling optimization method and system

The invention discloses a rapid forward modeling optimization method and system for three-dimensional gravity and gravity tensor, and the method comprises the steps: dividing an underground three-dimensional space into a plurality of layers of horizontal layered media, and constructing a discrete model of the underground space and an observation point; calculating a gravity and gravity tensor forward modeling coefficient matrix and a coefficient frequency spectrum matrix according to model subdivision, calculating a gravity value and a gravity tensor value of each depth layer corresponding to the density model by adopting a fast algorithm according to the coefficient frequency spectrum matrix, and superposing the forward modeling values of each layer to obtain gravity forward modeling anomaly of the density model. Furthermore, according to odd-even characteristics of real number sequence fast Fourier transform, under the condition that fast calculation efficiency is guaranteed, space complexity of a forward m