CPPsimplex

自己写了一个二维Euler方程的间断有限元程序 上次发了一个三角形单元的程序 因为不是曲边单元 所以在圆柱后面容易形成涡 现在把程序改为曲边四边形单元了 没有涡出现 单元是8节点四边形单元 节点编号顺序是 1 5 2 6 3 7 4 8 也就是四个角点依次 是1 2 3 4 然后是边的中点编号 5 6 7 8. 时间推进采用 Runge-Kutta 方法 数值通量采用全局Lax-Friedrichs通量 仍然不能捕捉激波 因为没有做重构或者加人工粘性 等这个做出来了 再发一次。 程序没有进行优化 比如说内存的消耗没有优化 比如直边单元的边界积分仍然采 用了曲边的积分方法 增加了计算量 比如面积分、线积分都是采用的是Gauss- Legendre-Lobatto积分 积分精度会比一般的Gauss-Legendre积分精度低一阶 等 等问题。 二维的 纯属交流性质 就没有考虑这些问题 ^_^ 如果物面全部是直边 那么只要改变一个参数N 就可以获得不同的计算精度 且具 有谱精度 因为单元的节点是Gauss-Legendre-Lobatto积分点。 其实就是谱元法 （物面是曲边的情况我不清楚是不是也可以通过提高基函数的阶数 也就是增加N 来提高计算精度）(Wrote a two-dimensional Euler equations with discontinuous finite element program Last made ​ ​ a triangular element of the program, not curved edge unit is so easy to form a vortex in the cylinder behind the Program to curved edge quadrilateral element vortices appear Unit is the order of 8-node quadrilateral element node number is 15,263,748 which is the four corners of the points in turn Is 1234 and then the side of the midpoint of the number 5678. Time promote the use of Runge-Kutta method Numerical flux of the overall situation of Lax-Friedrichs, flux Still can not capture the shock wave did not do the reconstruction or artificial viscosity do it Zaifayici. The program is not optimized for example, memory consumption is not optimized such as straight-edge boundary integral of the unit is still mining Integral method to increase the amount of computation such as surface integral with a curved edge, the line integral using the Gauss- The Legendr)

说明：  用LBM代码编写的由于温差而产生的自然对流小程序(As with the LBM code written in natural convection resulting from temperature applet)

用来画多输入多输出系统的格式带，输入是矩阵形式(draw gershgorin)

计算机流体理论方面的文献，动网格的划分和计算(Literature, of the theory of computational fluid dynamic division and calculation of the grid)

吉尔算法积分一阶微分方程组初值问题的C语言描述，包括主函数、计算微分方程组中各方程右端函数值的函数程序、计算雅克比矩阵的函数程序、矩阵求逆程序等。(GEAR algorithm integral first order differential equations initial value problem of the C language description, including the main function to calculate the differential equations in the equation right function value function procedures, functions Jacobian matrix calculation procedures, matrix inversion procedures.)

说明：  用刷选法求出100之内的素数。并输出数有多少个。(100 prime number is calculated by the method of selection. And the output count how many.)

极小 算法（Min-Min）、极大极小算法(Max-Min)、最大时间跨度算法（Max-Int）三种典型的映射算法的算法原理以及计算程序(Minimal algorithm (Min-Min), max-min algorithm (Max-Min), maximum time-span algorithm (Max-Int) three typical mapping algorithm and the algorithm of the calculation program)

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).)

利用Lax-wendroff两步差分格式求解一维激波管问题Fortran语言(Use a two-step Lax-wendroff Difference Scheme for Solving the one-dimensional shock tube problem Fortran language)

求解一维热传导方程，格式包括FTCS、BTCS、CNCS三种差分格式(solve one dimension heat transfer equation. )