zhuanzhi

Compute isotherms in quad

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. )

矩量法实例 计算细导线的雷达散射截面，PPT资料(Instance of the method of moments to calculate the radar cross section of thin wire)

sorting different kind of arrays

说明：  将GNSS RINEX数据转换为电离层总电子含量(GTEX格式)(Convert GNSS RINEX data to Ionospheric Total Electron Content (GTEX format))

％ SSOR预处理的共轭梯度法求解方程Ax=b ％ 输入参数说明 ％ A 正定矩阵[n*n] ％ b 右边向量 ％ omega SSOR预处理参数(0--2) ％ Times 迭代次数 ％ errtol 给定误差终止条件 ％ ％输出参数 ％ NewX 方程Ax=b的x近似解 ％ avgerr 求解的当前平均绝对误差( SSOR preconditioning conjugate gradient method for solving equations Ax = b the input parameter descriptions A positive definite matrix [n* n] b right side vector omega SSOR preconditioning parameters (0- 2) Times iterations errtol termination of a given error condition NewX output parameter equation Ax = b of x approximate solution to solve the current avgerr average absolute error)

二阶非线性耦合波方程组的计算 The calculation of the second-order nonlinear coupled wave equations(The calculation of the second-order nonlinear coupled wave equations)

说明：  一维波动方程的间断有限元计算，包括网格的划分，数值积分的计算等。(Discontinuous finite element method for one-dimensional wave equation, including mesh division, numerical integration calculation and so on.)

test1.txt 第一列为时间t，0.001s为步长；第二列为系统的输入信号；第三列为系统的输出信号。 signal_analyzer.m首先将test1.txt 的数据读入workspace，然后进行FFT，分析出两信号的频率，输出对于输入的幅值衰减（db），输出对输入的相位差。(test1.txt the first time as t, 0.001s for the step the second as the system input signal the third as the system output signal. signal_analyzer.m first test1.txt data read workspace, and then proceed to FFT, analysis of the two signals in the frequency, the output for input amplitude attenuation (db), the output of the input phase difference.)

本程序实现利用高斯全选主元法解矩阵方程，即高斯-约旦法解方程(This program Gaussian Select the primary element method for solving matrix equation, that Gauss- Jordan method of solving equations)