迭代计算

Based on the Saint-venant equations describing the channel flow movement, the nonlinear algebraic equations derived by the use of Preissmann weighted implicit four-point scheme are solved with the Netwon-Raphson method. A combined Gauss main-element elimination method with compress-storage technique is proposed. The relaxation iterative method for solving branch river networks is extended, which can turn the problem of any complex river networks into the problem of a series of single rivers. The coupling of hydraulic model with water quality model is built up. The combined model was applied to a large complicated river networks with numerical hydraulic structure which influenced by strong tide, storm and heave rain. Visualization of computational results is realized by means of MapInfo, which displays the computational results in fast, convenient and accurate way.

水力模型以描述河道洪水波运动的Saint-Venant方程组为基础，用Newton-Raphson方法直接求解按Preissmann加权四点格式进行离散所得的非线性代数方程组，提出了压缩存贮形式的Gauss列主元消去法并对数值解的收敛性进行了讨论；将支流流量的松弛迭代方法从树状河系推广到了环状河网，使任意复杂河网水力计算的问题都可化为一系列的单一河道的水力计算问题；建立了水力模型与水质模型的联接，初步应用于既有洪水、暴雨、强潮等综合影响，又存在多种水工建筑物及水力调度问题的大型复杂河网中的非恒定流水力、水质计算问题；利用MapInfo对计算结果的可视化进行了研究，有利于决策者快速、方便、准确地作出决策。

In the computation of aerodynamic forces, the present work is based on the work of Morino et al., but the following aspects are improved:(1) In computing the steady transonic aerodynamic load, the steady transonic nonlinear integral equation is solved by relaxation-iteration method in this thesis, instead of solving the time dependent transonic nonlinear integral equation, so that the computing time is saved greatly;(2) The influence coeifficients represented by volume integral are transformed to surface integral by using the Gaussian Theorem, so the analytical form of these coeifficients can be obtained and this leads to be more convenient to analyse and compile computer program;(3) The shock capturing method is used in every time step in present work, no shock moving term is added in the integral equation, so that it is more convenient and simpler to treat.

在气动力计算方面，本文基于Morino等人的工作，作了如下几方面的改进：（1）在计算定常跨音速流场（作为非定常绕流计算的初场）时，本文采用松驰迭代法直接求解跨音速定常非线性积分方程，而不是采用时间相关法求解非定常非线性积分方程，这样大大节省了计算机时；（2）将以体积分形式出现的影响系数化为面积分，并获得解析公式，这样便于分析和编写程序；（3）对运动的激波，本文通过在每一个时间步长上采用激波捕捉法而得到，而不是在积分方程中附加激波运动项，因而处理起来简单方便得多。

Establish the steady-state and transient model using the three hydrodynamics equations (Continuity equation, Momentum equation and Energy equation). By comparing different state equation, it selects the BWRS state equation which is considered the most accurate state equation in current natural gas measurement. It calculates compression factor, density and other Thermal parameters based on BWRS state equation. In Numerical solution of the steady-state and transient model, compression factor, friction coefficient and all the other Thermal parameters are recalculated in each small time step to reduce the numerical calculation error.

在稳态模型的建立上，利用流体力学三大方程(连续性方程、运动方程和能量方程)，通过比较不同的状态方程选用了目前被认为最精确的用于天然气计量的BWRS状态方程，并以此方程为基础进行压缩因子、密度等热物性参数的计算；在稳态模型的求解上，选用容易计算，精度较高的标准型龙格—库塔(Runge-Kutta)法进行数值求解，并且在迭代过程的每一小步都重新计算燃气的压缩因子，摩阻系数等所有的计算参数，以减少数值计算的误差。

Some new method is presented in this paper: A. An Integrated parameters computation method to analysis asynchronous operation of the turbine generator is given, including the equivalence of short circuit and open circuit of field windings, deducing boundary condition of 〓 method and computing frequency parameters. B. A new memory structure for sparse complex matrix and a PCCG method based on it are introduced to save memory and computation time. C. An equivalent method of vacuum is presented, and effectively eliminate the effect of corner point and accelerate convergence of PCCG method. D. Coupling the computation of electromagnetic and temperature field is discussed and model for computing temperature field of the turbine generator rotor at asynchronous operation is built.

文中提出了以下新方法：(1)在失磁异步运行转子三维涡流场计算中提出了完整的参数计算方法，其中包括励磁绕组开、短路的等效，〓法边界条件的推导及频率参数的计算方法；(2)提出了铁心内空气域的等效方法，有效地解决了开槽引起的角点奇异问题，并提高了方程组的迭代收敛速度；(3)在〓法有限元模型中，创立了一种能节约内存、提高计算速度的压缩存储矩阵格式，并建立了基于该格式的方程组解法；(4)提出了涡流电磁场和温度场两种不同场计算的合理结合方法，建立了转子三维稳态和时变温度场的有限元计算模型。

How to calculate precisely the circumstance function matrix for the gimbaled system is lucubrated. The method of using exterior data and the method of calculating iteratively are put forward. The simulation result shows that two methods can increase the calculating accuracy of the circumstance function matrix.

讨论了平台式系统环境函数矩阵的精确计算问题，提出了利用外测数据与应用迭代技术精确计算环境函数矩阵的方法，仿真计算表明，这两种方法能够有效提高环境函数的计算精度。

Using three dimensional inharmonic element and the modified subspace iteration scheme for calculating dynamic characteristic of the shear wall, and using plane stress element and Newmark and Newton-Raphson method for calculation of seismic behaviors of shear wall under earthquake loads.

采用三维非协调实体元及改进子空间迭代方法计算剪力墙的特征对；采用平面应力单元并利用Newmark法与Newton-Raphson法相结合的方法计算剪力墙在地震荷载下的地震反应，并用FORTRAN77（F90）语言编制了相应的计算程序和前后处理程序，经计算验证程序是有效的。

Rather than storing the end iterator, we must recompute it after each insertion

为了避免存储 end 迭代器，可以在每次做完插入运算后重新计算 end 迭代器值

The solution of the optimal 3-impulse rendezvous is a multi-variable iteration process. For the 3-impulse rendezvous with terminal coastings, the symmetry characteristic of optimal 4-impulse rendezvous was applied to reduce the number of the iteration variables to save the calculation consumption.

三脉冲最优解的求解采用多变量迭代的方法；对于存在端点滑行段的三脉冲最优解的求解，利用四脉冲最优解的对称性，减少迭代变量的数量，降低了计算量。

In order to analyze strength and vibration of impellers using finite element method, pre-processing and post-processing are necessary.

对于由于降阶得到的Hermite矩阵的特征值计算，提出了一种改进的子空间迭代方法，并推导了相应的广义雅可比方法的迭代公式。

An effective algorithm is proposed, which is based on hard-decision for some specially received symbols far away from normal symbols on the constellation. Then according to the distance between received symbols and decoded symbols, the pseudo Log-Likelihood-Ratio is calculated, and taken as the pseudo initialization information for the next iteration.

该算法首先对接收符号星座图中特别奇异点进行硬判决&校正&，然后利用接收符号和译码判决符号在星座图中的距离，在每次迭代前计算符号的伪似然比，作为下次迭代的伪初始信息。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。