big-intger-plus-minus-multiply

Orthogonal Polynomials Approximation 数值分析，计算正交基多项式的系数 (Given a function f and a set of m >0 distinct points . You are supposed to write a function to approximate f by an orthogonal polynomial using the exact function values at the given m points with a weight assigned to each point . The total error must be no larger than a given tolerance. Format of function int OPA( double (*f)(double t), int m, double x[], double w[], double c[], double*eps ) where the function pointer double (*f)(double t) defines the function f int m is the number of points double x[] contains points double w[] contains the values of a weight function at the given points x[] double c[] contains the coefficients of the approximation polynomial double*eps is passed into the function as the tolerance for the error, and is supposed to be returned as the value of error. The function OPA is supposed to return the degree of the approximation polynomial. Note: a constant Max_n is defined so that if the total error is still not small enough when n = Ma)

严格的衍射积分计算，实现光栅结构透过反射场2维分布的严格解计算，利用散射积分对耦合模方程进行严格计算解 衍射，光栅，场，二维，积分，散射矩阵，耦合模理论(Strict calculation of the diffraction integral, the grating structure is realized through the rigorous solution of the 2 dimensional distribution of the reflection field. Diffraction, grating, field, two-dimensional, integral, scattering matrix, coupled mode theory)

超级好用的书，面试必备，包括常用的算法介绍，面试题目等等(Super easy to book, interview essential, including the commonly used algorithm is introduced, interview questions, etc.)

说明：  用FORTRAN语言实现二维欧拉方程的求解，采用二阶MUSCL迎风格式()

汪德灌教授那本 计算水力学书后的 perisiman 隐式差分法源代码的 c++版本，我是在fortran代码中改过来的，书中的fortran代码有错误， 请较高人才得以突破 这个东西应该比较有用的吧， 尤其对刚接触这方面知识的 注释很详细哦 而且有输入文件(Professor Wang Deguan that the calculation of hydraulics perisiman after the implicit difference method source code c++ Version, I was changed from fortran code, and the book fortran code error, please talents to break with this higher things you should be more useful, especially for刚接触this regard very detailed knowledge of the Notes and the input file Oh)

糊涂先生给他的五个朋友写信，他写了五封信，但是当他的朋友收到信后，都告诉他：“你的信寄错了”。那么请你计算一下：出现这种情况的概率有多少？（假设糊涂先生是随机地往信封里装信的），你能不能把所有的情况都列出来呢(Mr. foolish to write him five friends, he wrote five letters, but when his friend received a letter, told him: )

计算复序列的分裂基快速傅里叶变换，分裂基快速算法是将基2和基4分解组合而成。在基2M类快速算法中，分裂基算法具有最少的运算量，且仍保留结构规则、原位计算等优点。(Calculate complex sequence of split radix fast Fourier transform, fast algorithm is to split the base base 2 and base 4 decomposition combination. 2M fast algorithm in the base class, the split-based algorithm has the least amount of computation and structural rules remain in situ calculation and so on.)

说明：  在进行激光熔覆或者焊接时可用到的移动热源命令流(Command flow of moving heat source available during laser cladding or welding)

数值计算实例，主要有LU分解，龙格库塔法，高斯分解法，欧拉法，曲线拟合，曲线插值(Numerical example)

四阶龙格库塔法 数值计算 C++源码 可直接运行(Fourth-order Runge-Kutta numerical method C++ source code can be run directly)