The key of the tomography lies in solving the equation group whose coefficient matrix is a large sparse one, and the LSQR algorithm is used here. This algorithm has many advantages that other iterative methods don't have. The calculation instance has proved that the results of the LSQR method are clear and reliable, and hence it has been widely used.d:\PDF\.pdfd:\PDF\.pdf
杨薇, 刘四新, 冯彦谦. 跨孔层析成像LSQR算法研究[J]. 物探与化探, 2008, 32(2): 199-202.
YANG Wei, LIU Si-xin, FENG Yan-qian. A STUDY OF THE LSQR ALGORITHM FOR CROSS-HOLE TOMOGRAPHY. Geophysical and Geochemical Exploration, 2008, 32(2): 199-202.