mathmatics_of_computer

FFT快速傅里叶变换，用于数字信号处理，大大提高了运行速度，节省内存开销。C语言实现(FFT fast Fourier transform for digital signal processing, greatly improving the speed and save memory overhead. C language)

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: )

这些代码可以用于产生一系列随机数，可以根据需要使用。(These codes can be used to generate a series of random numbers may be used as needed.)

多目标遗传算法，求得pareto最优解集，可以用于各种工程的数学计算(Multi-objective genetic algorithm, pareto optimal solution set is obtained, can be used for a variety of engineering mathematics)

PMV，的热舒适指标计算程序VB编码，可供参考(PMV, thermal comfort index calculation program VB code, for reference)

一个通过高斯正反算公式计算高斯投影后投影平面的二维坐标，也可通过坐标反算大地经纬度。提供54系，西安80系，WGS-84系和CGCS2000系四种椭球参数。(A positive and negative Gaussian Formulas to calculate the two-dimensional coordinates of the Gauss projection projection plane can also be computed from coordinates latitude and longitude of the earth. 54 Department of the the Xi' an 80 series, WGS-84 system and CGCS2000 Department of four oval ball parameters.)

有限元n维实体材料单元，仅供科研用途，拒绝商业使用(N-dimensional finite element solid material element, for scientific purposes, refusing commercial use)

根据物理学的毕奥-萨法尔定理，计算环形线圈周围电磁场的强度。。(According to physics, Biot- Safar theorem, calculate the intensity of electromagnetic field around the circular coil. .)

说明：  LDL分解。作为矩阵方程数值解法最基础的矩阵分解算法，LDL算法可以高效分解对称矩阵。(LDL decomposition. Numerical Solution of matrix equation as the most basic matrix factorization algorithm, LDL decomposition algorithm can be efficient symmetric matrix.)

说明：  LM算法的c语言实现 拟合的函数为gauss函数(Levenberg-Marquardt Method)