This program solves the equation on the interval (0,1) plus boundary conditions of Dirichlet or Neumann type with the finite elemnt method. Linear and quadratic finite elemnst are included. In the case were an exact solution is given the L2-Error,

线性和二次型时频表示（傅里叶变换和Cohen类、Affine类时频分布）-Linear and quadratic time-frequency representation (Fourier transform, and Cohen, the Affine class of time-frequency distribution)

程序均用matlab编写 ch ex 的文件是信号与系统频谱密度函数或者时移特性的展示 Advanced_Mathematica_picture_zoom是利用二次线性内插值法对彩色图片进行任意倍数的放大 每个程序都含有详细的注释-Programs are written in matlab chex file is spectrum density of signal and system function or moving features of the display