Frequency-domain waveform seismic tomography includes modeling of wave propagation and full waveform inversion of correcting the initial velocity model. In the forward modeling, we use direct solution based on sparse ...Frequency-domain waveform seismic tomography includes modeling of wave propagation and full waveform inversion of correcting the initial velocity model. In the forward modeling, we use direct solution based on sparse matrix factorization, combined with nine-point finite-difference for the linear system of equations. In the waveform inversion, we use preconditioned gradient method where the preconditioner is provided by the diagonal of the approximate Hessian matrix. We successfully applied waveform inversion method from low to high frequency in two sets of Marmousi data. One is the data set generated by frequencydomain finite-difference modeling, and the other is the original Marmousi shots data set. The former result is very close to the true velocity model. In the original shots data set inversion, we replace the prior source with estimated source; the result is also acceptable, and consistent with the true model.展开更多
岩土工程规模大,加上岩土介质复杂的特性,使得当前有限元数值模拟在时间和精确度上很难达到工程要求。研究了在普通 PC 机群上实现的大规模并行有限元方法,以更好地发挥有限元在岩土工程中的应用。组建了Windows 下 PC 机群并行系统。...岩土工程规模大,加上岩土介质复杂的特性,使得当前有限元数值模拟在时间和精确度上很难达到工程要求。研究了在普通 PC 机群上实现的大规模并行有限元方法,以更好地发挥有限元在岩土工程中的应用。组建了Windows 下 PC 机群并行系统。采用“分而治之”的并行策略实现有限元并行,并实现了存储局部化。采用基于区域分解预处理技术的并行共轭梯度法来实现方程组的求解。集成以上方法,用 C++开发了并行有限元程序ParallelGeoFEM。对水布垭地下厂房进行了三维有限元并行模拟,得到了较好的加速比。结果表明,基于区域分解的并行有限元方法可以实现岩土工程大规模快速精细的模拟。展开更多
基金Supported by the National Natural Science Foundation of China (69983005)
文摘Frequency-domain waveform seismic tomography includes modeling of wave propagation and full waveform inversion of correcting the initial velocity model. In the forward modeling, we use direct solution based on sparse matrix factorization, combined with nine-point finite-difference for the linear system of equations. In the waveform inversion, we use preconditioned gradient method where the preconditioner is provided by the diagonal of the approximate Hessian matrix. We successfully applied waveform inversion method from low to high frequency in two sets of Marmousi data. One is the data set generated by frequencydomain finite-difference modeling, and the other is the original Marmousi shots data set. The former result is very close to the true velocity model. In the original shots data set inversion, we replace the prior source with estimated source; the result is also acceptable, and consistent with the true model.
文摘岩土工程规模大,加上岩土介质复杂的特性,使得当前有限元数值模拟在时间和精确度上很难达到工程要求。研究了在普通 PC 机群上实现的大规模并行有限元方法,以更好地发挥有限元在岩土工程中的应用。组建了Windows 下 PC 机群并行系统。采用“分而治之”的并行策略实现有限元并行,并实现了存储局部化。采用基于区域分解预处理技术的并行共轭梯度法来实现方程组的求解。集成以上方法,用 C++开发了并行有限元程序ParallelGeoFEM。对水布垭地下厂房进行了三维有限元并行模拟,得到了较好的加速比。结果表明,基于区域分解的并行有限元方法可以实现岩土工程大规模快速精细的模拟。
