polyfit

提供函数能进行1维2维的FFT，输入输出的序列长度应为2的整数次方倍(Provides functions can be one-dimensional two-dimensional FFT, sequence length input and output should be an integer power of 2 times)

说明：  邓肯张在ansys中的二次开发，适合于土体有限元分析(second development of duncan-zhang in ansys,it s be used to ansys)

说明：  一维黎曼问题，一维问题，即激波管问题，是一个典型的一维可压缩无黏气体动力学问题，并有 解析解。对它采用二阶精度两步差分格式进行数值求解。(Riemann problem, One dimensional problem, the shock tube problem, is a typical one-dimensional compressible non viscous gas dynamic problem with analytic solutions. It is solved numerically by two order two step difference scheme.)

若矩阵A中的某一元素A[i，j]是第i行中的最小值，而又是第j列中的最大值，则称A[i，j]为矩阵A中的一个鞍点。请写出一个可确定此鞍点位置的算法（如果这个鞍点存在）。(If the matrix A, an element A [i, j] is the minimum value in the i-th row, but is the maximum value of the j-th column, then A [i, j] for the matrix A is a saddle point. Please write a algorithm to determine the position of saddle point (saddle point exists).)

C 语言，模拟流体相平衡过程，得到混合气体平衡态以后的工况参数(C language to simulate fluid phase equilibrium process, to obtain a mixed gas equilibrium after working parameters)

渗流计算，渗流浸润线的计算，溢出点高程的确定(seepage computation)

平常练习的一些程序，比较基础，包括求斐波那契数、完数等等(Some of the usual practice procedures, more infrastructure, including seeking Fibonacci numbers, number, etc. End)

实现扫雷功能,基于c语言实现的，能够控制输入矩阵的大小(Implement demining capabilities, based on the c language, able to control the size of the input matrix)

最小二乘法拟合进行n次多项式拟合，N用来控制拟合的次数，例如N=5时进行4次多项式拟合，还回的是拟合系数(Least squares fit polynomial n times, N is used to fit the number of control, e.g., N = 5 When quartic polynomial fitting, further back are fitting coefficients)

对于水轮机阀门开启、关闭的一瞬间，对于钢管有比较大的水击。该程序计算出了相对最大的水击压力。(For turbine valves opened, the closure of the moment, for a relatively large pipe water hammer. The program calculated the maximum relative pressure of water hammer.)