查询词典 truncation error

In the PFD, both the differentials and non-differential terms in the differential equation are discretized, and the coefficients of the power series are determined by means of eliminating the truncation error of the corresponding modified scheme, then the high accurate difference scheme is obtained.

摄动有限差分方法在微分方程的差分近似中，离散微商项的同时，也离散非微商项，把非微商项摄动展开成网格步长△x的幂级数，并通过提高差分格式相应修正微分方程误差阶的方法求出摄动幂级数系数，从而获得高精度差分格式。

Based on Crank-Nicoson's technique, and a new approach for the numerical simulation of the model is raised. The truncation error of the one step difference method reaches O (△t^2+△x^2) and of quite good stability condition.

基于Coriolis加速度和Lagrangian应力公式，利用Newton第二定律导出轴向加速度运动弦线横向振动的动力学模型；通过线性变换将方程化为一阶无量纲的非线性微分方程组；并利用Crank-Nicoson的中点离散技巧，给出运动方程的单步二阶差分方法；算法把对运动方程和本构方程分别离散，使之可以用于不同本构的运动弦线的数值仿真。

Both upper bound formula and lower bound formula of the global truncation error of Euler method have been derived theoretically.After making certain approximat e processing,the derived upper formula changes into current upper bound formula.

从理论上推导出了欧拉方法的整体截断误差的上限公式和下限公式，作一定的近似后，得到的整体截断误差上限公式就变为现用的整体截断误差上限公式。

Three-dimension parabolic equation ; high precision ; explicit difference scheme ; truncation error

三维抛物型方程；高精度；显式差分格式；截断误差

Automatic differentiation and implicit function differentiation rule were used to calculate the precise absolute and relative sensitivity coefficients, with no truncation error introduced.

提出一种基于自动微分和隐函数求导法则的精馏塔优化计算灵敏度分析方法，可以求出精确的、无截断误差的灵敏度系数，以反映精馏塔模型中各种不确定因素变化所引起的改变和影响。

A direct evidence for intermittency induced by truncation error is provided in the paper.

一个截断误差诱导阵发混沌的直接证据。

The instrument simultaneously sample for three phase voltage and current. Rotary photoelectric coding switch and LCD are used for human-computer interaction. it makes the interface compact and efficient. Utilizing the function of positive and negative edge trigger of the programmable counter array unit in MPU, signal zero-cross is captured for the phase detected based on double way. The software synchronism sampling method based on real-time parameter self-optimizing minishes period truncation error, and the measurement accuracy is improved. The digitization power measure imports traditional two-unit and three-unit methods and expands application range of the instrument. The capacity is discriminated by soft ware table-look-up on the load loss. The value of a quantity is converted to the value when reference temperature (75 ℃) from test temperature.

该仪器具有以下特点：仪器对三相电压电流同时采样；基于旋转式光电编码器和液晶显示屏的人机交互界面简洁而高效；可编程计数器阵列PCA"捕获"信号的过零点用于双向过零平均鉴相，得到准确的相位差和周期；基于实时参数自寻优的软件同步采样，有效地减小了周期截断误差，提高了测量准确度；数字化功率测量引入了传统的二表法和三表法，扩展了仪器的使用范围；实际容量根据负载损耗用软件查表的方法来判别；测量值已从试验温度折算到了参考温度(75℃)时的值。

Introduced the mathematics theories foundation of the symplectic schemes, include the commonly established methods for construction symplectic schemes, which are symplectic Runge- Kutta method, symplectic propagation techniques and generating function method. A minimization of the truncation error-function and optimal Courant-Friedrichs-Levy number schemes are well established using sympletic propagation techniques.

介绍了辛算法的数学理论基础，包括辛算法常见的构造方法：辛Runge-Kutta法，辛传播子技术及生成函数法，利用辛传播子技术结合误差最小化及稳定性Courant-Fredrichs-Lewy条件数最大化的两种优化方案，构造了新的传播子系数；(2)。

By comparison with some traditional differentiation methods, such as divided differences, by-hand coding and symbolic differentiation, AD is characterized by a lot of virtues, e.g., truncation error free, less running cost and less human labor required.

比起传统意义上的计算微分方法来，自动微分具有计算精度高、计算代价小及投入人力少等优点。

This paper proposed a method to estimate and compensate the differential truncation error using tracking and telemeted data.

如何辨识和估计观测数据包含的各种误差，理论和实际均做了大量讨论，建立了诸多比较实用的方法[2～4]。

Chrysanthemum of 10 thousand birthday is lax to edaphic requirement, with the arenaceous qualitative loam with fecund, good drainage had better.

万寿菊对土壤要求不严，以肥沃。排水良好的砂质壤土为好。

He unstepped the mast and furled the sail and tied it.

他拔下桅杆，把帆卷起，系住。