random

己知一些离散的点，使用matlab利用最小二乘法拟合(Had a number of discrete points, with linear least squares fitting)

说明：  使用fortran编写的无网格（光滑质点流体动力学）SPH算法(using FORTRAN prepared by the non-grid (smooth particle hydrodynamics) SPH algorithm)

用三元组表为结构，实现稀疏矩阵的加法并输出。(Achieve sparse matrix addition)

多重网格方法求解矩形边界条件下泊松方程，偏微分方程数值求解(use multigrid method to solve poisson equation in rectangular domain)

使用BP神经网络预测农产品的需求，论文在知网上应该就一篇。(Using neural network to predict the demand of agricultural products)

采用 Lax-Wendroff算法计算非粘Bergers方程(nonviscous Burgers equation, Lax-Wendroff method.)

C-N解偏微分方程的程序。解的是定步长的抛物型偏微分方程： du/dx - a * d2u/dx2 = 0 在程序中可以更改 a 的值以实现不同系数的解。在循环中改变 a 的值以实现变系数. 该说明在压缩包是也有(CN solution of partial differential equations procedures. Solution is scheduled to step parabolic partial differential equation: du/dx- a* d2u/dx2 = 0 in the procedure can be changed in order to realize the value of a different coefficient of the solution. Change in the cycle in order to realize the value of a variable coefficient. The note in the compressed packet is also)

说明：  四级四阶龙格库塔格式，求解微分方程的好算法。(Four fourth-order Runge-Kutta format, a good algorithm for solving differential equations.)

A finite element fortran code for 2-D truss

转载：众所周知有限元解决振动问题的能力还是有限的, 比如做齿轮啮合过程的动力学模拟就要同时涉及到接触和动力反映两个主要方面. 目前处理此类问题最成熟的软件当属MSC.ADAMS, 但ADAMS也只能在模拟过程中做到弹性与刚性接触而已! 据我所知, 已不止两位研究生试图用LS-DYNA来做此类模拟, 他们忽略了(或没搞清楚) LS-DYNA只能处理瞬态问题, 而对于该过程的模拟也是无能为力的!!! 结果是浪费了大量的时间, 甚至机会. 这本应是导师的责任, 但许多高龄导师对现代软件的不熟悉也是....那么此类问题的具体解决方案在哪里? Vibration Simulation Using Matlab and ANSYS 给出了答案. 掌握书中的内容意义非同小可! 这对于要从事CAE工作的将会受益(起码在今后20年内).随着我国经济的高速发展 解决资本积累必将是要遇到的问题, 工程(设备)维护, 系统监测也将(象发达国家)成为CAE非常重要的部分. 早早入手就能使你立于不败之地!(This book has three main purposes. The first purpose is to cc..-ct in one document the various methods of constructing and representing dynamic mechanical models. The second purpose is to help the reader develop a strong understanding of the modal analysis technique, where the total response of a system can be constructed by combinations of individual modes of vibration. The third purpose is to show how to take the results of large finite element models and reduce the size of the model (model reduction), extracting lower order state space models for use in MATLAB.)