]*>","")" /> 辛几何算法在射线追踪中的应用

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辛几何算法在射线追踪中的应用

陈景波,秦孟兆   

  1. 中国科学院数学与系统科学研究院计算数学与科学工程计算研究所;中国科学院数学与系统科学研究院计算数学与科学工程计算研究所
  • 出版日期:2000-04-20 发布日期:2000-04-20

陈景波,秦孟兆. 辛几何算法在射线追踪中的应用[J]. 数值计算与计算机应用, 2000, 21(4): 255-265.

RAY TRACING BY SYMPLECTIC ALGORITHM

  1. Chen Jing-bo; Qin Meng-zhao (Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and Systems Sciences Chinese Academy of Sciences)
  • Online:2000-04-20 Published:2000-04-20
Ray tracing is a basic aspect in tomography. To solve the caustic problem in inhomogeneous media using Maslov asymptotic theory, we need to calculate the position and slowness vector at every point. Therefore, ray tracing must rely on the ray equations in Hamiltonian form. In this paper, fourth order symplectic scheme and nonsymplectic Runge-Kutta scheme are compared in ray tracing for sinusoidal velocity model. The result indicates that ray paths obtained by two schemes are almost the same. But on keeping Hamilton quantities, the symplectic scheme is far better than the Runge-Kutta scheme. On computing travel time for Htamiltonian system with T parameter, we use trapezoid formula for numerical integration. The result coincides with that obtained using Hamiltonian system with t parameter.
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