Numerical Approximation of Adjoint Blasius Equation Using MATLAB

在Volterra的封闭系统中，人口增长模型的无量纲形式为 k(du/dt) = u - u^2 - u ∫_0^t u(x) dx。该GUI允许用户输入初始总体 u0、无量纲常数 k、最终时间 Tmax 和网格点数 M。通过单击适当的按钮，用户可以使用各种数值方法生成图。 \"毒性项\" 是积分 ∫_0^t u(x) dx。面板“毒性术语的梯形规则”和“毒性术语的辛普森规则”首先对毒性术语应用正交规则，然后使用指定的数值方法求解所得系统。有关更多信息，请参阅 (1)。有关问题的全面分析，请参阅： 1. Kevin G. TeBeest，Volterra*人口模型的数值和解析解，SIAM Rev. 39 (1997)，第1期。3, 484-493。 2. RD Small，《封闭系统中的人口增长》，SIAM评论25（1983），第1期。1, 93-95。

本书提供了用Matlab进行数值计算的丰富资料，内容可读性、知识性和实用性都非常强。

This method can solve various partial differential equations and represents the latest numerical solution techniques. It is based on MATLAB programming, making it easier to understand and implement. By utilizing MATLAB, complex mathematical models become more accessible and the process of solving PDEs is streamlined for better clarity and efficiency.

泊松方程的数值解（二维情况）采用有限差分法进行求解。

本程序介绍了应用最为广泛的椭圆型、双曲型、抛物型偏微分方程的数值解法，并详细编程实现了每种方程的多种常见数值解法。附件中使用MATLAB编程来实现这些算法。

This program was developed based on personal needs and allows for numerical integration of multiple x-values and their corresponding function values using Simpson's 1/3 Rule, Trapezoidal Rule, and the Composite Trapezoidal Rule. The only input required from the user is in lines 2 and 3, where they must insert their data points. For example:?ta Input: x = [1,2,3]; y = [2,2,3];This method is much faster than using an online calculator, where you have to wait a few seconds to see the result. :)

插值动画：本项目探讨了动画多项式近似的递增顺序，提升动画表现力。当前版本的剪辑可观看：点击这里

数值方法(MATLAB版)(第四版)中文版.pdf

3.2 Genetic Operators (1) Crossover Operator The crossover operator randomly pairs individuals from the parent population for crossover operations, generating ( m ) offspring individuals to form the next generation. Two types of crossover are employed: single-point crossover and two-point crossover. Given two individuals for crossover ( P = {p_1, p_2, p_3, \dots, p_n} ) and ( Q = {q_1, q_2, q_3, \dots, q_n} ), a random crossover point ( b_1 ) is chosen from the range [1, n] for single-point crossover. The elements before ( b_1 ) in ( P ) are copied to offspring individual ( \text{new Individual1} ), while the remaining elements are copied from ( Q ). Similarly, a second offspring ( \text{new Individual2} ) is generated by swapping the roles of ( P ) and ( Q ). In two-point crossover, two random crossover points ( b_1 ) and ( b_2 ) are chosen, and the elements between ( b_1 ) and ( b_2 ) in ( P ) are copied to the offspring, with the remaining elements taken from ( Q ). (2) Mutation Operator After the crossover operation, two mutation operators are applied to the offspring individuals. The first is rotation mutation, where a random position ( \text{bit} ) is chosen, and with probability ( p_m1 ), the portion of the individual after ( \text{bit} ) is rotated. The second is position mutation, with a smaller probability ( p_m2 ), two integers ( \text{bit1} ) and ( \text{bit2} ) are randomly chosen from the range [1, n], and the corresponding parts of the individual are swapped. (3) Selection Operator The fitness of the mutated offspring individuals is evaluated using the lowest level line method. The parent and offspring individuals are ranked by their fitness in descending order, and the top ( m ) individuals are selected as the next generation's parents. 3.3 Termination Criteria The steps in sections 3.2(1), 3.2(2), and 3.2(3) are repeated until the fitness of the best solution meets the required threshold or the pre-defined number of generations is reached. At this point, the optimal solution is output. 4. Case Study To test the performance of the algorithm, two cases from literature [3] are solved. In Case 1, a large rectangle of size ( 15 \times 40 ) is divided into 25 smaller rectangles. Based on the lowest level line method, the corresponding coding sequence is ( \text{Opt} = {1, -9, 11, -15, 17, -24, -25, -10, -14, -22, -23, -2, -3, -5, 18, 7, -8, -12, 19, -20, 21, 6, 13, 4} ). The width is set at 40, and height considerations follow suit for the genetic algorithm implementation.