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HongXinHUANG 《中国化学快报》2004,15(4):501-504
In this paper we proposed a novel exact fixed-node quantum Monte Carlo (EFNQMC)algorithm,which is a self-optimizing and self-improving procedure,In contrast to the previous EFNQMC method,the trial function is optimized synchronistically in the diffusion procedure,but not before the beginning of EFNQMC computation.In order to optimize the trial function,the improved steepest descent technique is used,in which the step size is automatically adjustable.The procedure is quasi-Newton and converges super linearly.We also use a novel trial function,which has correct electron-electron and electron-nucleus cusp conditions.The novel EFNQMC algorithm and the novel trial function are employed to calculate the energies of 1^1A1 state of CH2,^1Ag state of C8 and the ground-states of H2,LiH,Li2,H2O,respectively.The test results show that both the novel algorithm and the trial function proposed in the present paper are very excellent. 相似文献
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提出剩余函数量子Monte Carlo的一个新算法,这是一个自优化和自改善的过程.与以前的算法相比,本算法中的试探函数的优化是在剩余函数方法中同步进行的,而不是在变分Monte Carlo计算之前.为了优化试探函数,使用一种改进了的速降法,这是一个步长能够自动调节,超线性收敛的优化技术.在这个算法中,还使用了一种新的相关函数,它满足电子与电子以及电子与核奇点条件.此方法已被用于计算H2、LiH、Li2、H2O分子的基态以及CH2的X 3B1态、1 1A1态和2 1A1态的能量值. 相似文献
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Łukasz Stettner 《Applied Mathematics and Optimization》1993,27(2):161-177
We control a discrete-time uniformly ergodic system, which depends on an unknown parameter 0 A, a compact set. Our purpose is to minimize the long-run average-cost functional. We estimate the unknown parameter using the biased maximum likelihood estimator and apply the control which is almost optimal for the value of estimation. This way we construct strategies such that the value of the cost functional can be arbitrarily close to the optimal value obtained for 0. 相似文献
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