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21位水仙花数的寻找，里面用到了大数乘法等细节上的东西。(find the 21 digits narcissus.)

matlab的时频分析工具箱，含全部工具箱程序(Matlab time-frequency analysis toolbox, including all toolbox programs)

说明：  借助python3计算偏微分方程组，并作出相应图形，代码简单易懂，方便修改(Calculate partial differential equations)

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说明：  用混合同余法生成两组伪随机数，利用投针试验求圆周率。软件：matlab。(Two groups of pseudo-random numbers are generated by the method of mixed congruence, and the circularity is calculated by the test of inserting needle. Software: MATLAB.)

本程序在matlab中运行。 Generate_SystemMatrix是一个计算OSEM，MLEM迭代图像算法中系统矩阵的函数，其用法Generate_SystemMatrix（pixel），为所要重建图像的大小，一般为64,128,256，pixel也大运算越慢。 里面的diedai-test文件是一个简单的MLEM重建算法，其中要加载SystemMatrix矩阵就是Generate_SystemMatrix(128)的结果，注意如果要运行diedai-test，生成的系统矩阵名要保存为SystemMatrix，否则出错。 testsino是一个正弦图实例，就是MLEM算法中的投影矩阵，机算是数据。(This program is run in matlab. The Generate_SystemMatrix is ​ ​ a calculation of the OSEM, a function of the system matrix MLEM iterative image algorithm, its use Generate_SystemMatrix (pixel) to rebuild the image size, usually 64,128,256, pixel also large computing slower. Inside diedai-test file is a simple MLEM reconstruction algorithm, which load SystemMatrix matrix is ​ ​ the result of Generate_SystemMatrix (128), pay attention to if you want to to run diedai-test, the generated system matrix is ​ ​ saved as SystemMatrix, otherwise an error. testsino instance of a sinogram projection matrix MLEM algorithm, machine be regarded as data.)

比较完善的面向对象的有限元程序代码，适用于编写大型程序的学习(typical C++ code for OOFEM)

四分之一圆柱贴体网格的生成，可以调节大小(Fourth cylindrical body-fitted grid generation, you can adjust the size of the)

说明：  Copula and tail dependence

用C语言实现二重积分数值计算，精度较高；并且仿照程序中实现二重积分的思想，可以很容易扩展到三重以上的积分。(Using C language to achieve double integral numerical calculation, high accuracy and follow the procedures realize the idea of double integral, can be easily extended to more than triple the points.)