利用ICCG迭代技术加快电阻率三维正演计算

一般而言，有限差分法求解点源三维地电场正问题所形成的大型稀疏线性方程组Ａｘ＝ｂ，直接解法的计算效率极低。本文从系数矩阵Ａ的不完全Ｃｈｏｌｅｓｋｙ分解及矩阵特征值的特点等角度，说明了不完全Ｃｈｏｌｅｓｋｙ共轭梯度（ＩＣＣＧ）迭代技术可大大提高电阻率三维正演速度的内在原因。结合矩阵Ａ的稀疏存储模式，使得内存需求也大大减少。

3-D RESISTIVITY FORWARD CALCULATION ACCELERATEDBY ICCG ITERATION TECHNIQUE

For the large sparse linear equations: A x=b, which are formed from the finite difference method used to solve the 3D forward problem of geoelectrical field,in general,the computational efficiency with direct method is quite slow.In this paper,from the view point of the characteristics of the incomplete Cholesky decomposition of matrixX A and its eigenvalue,the internal cause of greatly increased 3D resistivity forward speed using the incomplete Cholesky conjugate gradient (ICCG) iteration technique is explained .Introducing the rowindexed sparse storage mode to store matrix A, the internal storage demand is greatly decreased.